EP4652869A1

EP4652869A1 - Method of controlling an aerosol generating apparatus

Info

Publication number: EP4652869A1
Application number: EP24177566.7A
Authority: EP
Inventors: designation of the inventor has not yet been filed The
Original assignee: Imperial Tobacco Ltd Great Britain
Current assignee: Imperial Tobacco Group Ltd
Priority date: 2024-05-23
Filing date: 2024-05-23
Publication date: 2025-11-26
Also published as: WO2025242556A1

Abstract

There is provided a computer-implemented method for controlling the operation of an aerosol-generating apparatus (1). The aerosol-generating apparatus comprises: a storage portion (32) for storing an aerosol precursor (6), a piezoelectric transducer (100) for aerosolizing the aerosol precursor (6), wherein an aerosolizing surface of the piezoelectric transducer is in fluid communication with the storage portion (32), a communications interface (16) communicatively connected to the piezoelectric transducer (100), and a processor configured to control one or more operational parameters of the aerosol-generating apparatus (1). The method comprises: receiving, at a user device (82) communicatively connected to the communications interface of the aerosol-generating apparatus, data indicative of the one or more operational parameters; receiving, by a user interface of the user device (82), user input indicative of a desired operating outcome of the aerosol-generating apparatus; generating instructions, based on the received data and the received user input, for causing the aerosol-generating apparatus to adjust at least one of the one or more operational parameters to achieve the desired operating outcome; and transmitting the generated instructions to the communications interface of the aerosol-generating apparatus, wherein the processor is configured to execute the generated instructions to adjust the at least one of the one or more operational parameters to achieve the desired operating outcome.

Description

FIELD

The present disclosure relates to an aerosol generating apparatus.

BACKGROUND

A typical aerosol generating apparatus may comprise a power supply, an aerosol generating unit that is driven by the power supply, an aerosol precursor, which in use is aerosolised by the aerosol generating unit to generate an aerosol, and a delivery system for delivery of the aerosol to a user.
In some cases, the aerosol generating unit may include an ultrasonic generator e.g. a piezoelectric transducer (PET) for generating the aerosol. In use, the surface of the PET will expand and contract as it vibrates.
A PET generates aerosol by causing cavitation to occur within a liquid aerosol precursor that is provided on a surface of the PET. Cavitation refers to the phenomenon where the static pressure of a liquid reduces to below the liquid's vapour pressure, leading to the formation of small vapour filled cavities within the liquid. When the cavities are subsequently subjected to a higher pressure, the cavities collapse resulting in a shock wave that propagates through the liquid. This shock wave induces capillary waves, or ripples, in a surface distal (referred to herein as the upper surface of the liquid) from the PET that may form ligaments to expel droplets from the upper surface. More succinctly, in a thin layer of liquid, the collapsing of the cavities can induce a disturbance in the liquid that causes liquid droplets to be expelled from liquid, thereby forming an aerosol over the surface of the liquid, typically within an aerosolisation chamber.
In the context of a PET for generating the aerosol, when the surface of the PET expands, the liquid on the surface will conform to the expanded surface. When the surface of the PET subsequently contracts, the static pressure in the liquid will fall as it is effectively dragged with the surface with the decrease in static pressure being proportional to the speed of the movement of the PET surface (i.e., the frequency of the vibration). If the frequency and amplitude of vibration of the PET is sufficiently high, cavitation will occur as a result of the contraction.
When the surface of the PET subsequently expands, the static pressure in the liquid will rise as it is effectively compressed by the surface with the increase in static pressure being proportional to the speed of the movement of the PET surface (i.e., the frequency of the vibration). Any cavities in the liquid previously formed may then implode, generating shock waves in the liquid capable of expelling droplets to form an aerosol.
In an aerosol generating apparatus using a PET, a liquid aerosol precursor is typically applied to the PET surface using a wick in fluid communication with a tank. The aerosol generated by cavitation of the liquid aerosol precursor will be drawn from the aerosolisation chamber along an aerosol flow path by suction at a mouthpiece outlet.
Aerosol generating apparatuses that use a PET for generating the aerosol present numerous challenges, including accurately driving the vibrational element and inefficiencies in the requisite circuitry.
In spite of the effort already invested in the development of aerosol generating apparatuses/systems further improvements are desirable.

SUMMARY

In an aspect, the present disclosure provides a computer-implemented method for controlling the operation of an aerosol-generating apparatus. The aerosol-generating apparatus comprises: a storage portion for storing an aerosol precursor; a piezoelectric transducer for aerosolizing the aerosol precursor, wherein an aerosolizing surface of the piezoelectric transducer is in fluid communication with the storage portion; a communications interface communicatively connected to the piezoelectric transducer; and a processor configured to control one or more operational parameters of the aerosol-generating apparatus. The method comprises: receiving, at a user device communicatively connected to the communications interface of the aerosol-generating apparatus, data indicative of the one or more operational parameters; receiving, by a user interface of the user device, user input indicative of a desired operating outcome of the aerosol-generating apparatus; generating instructions, based on the received data and the received user input, for causing the aerosol-generating apparatus to adjust at least one of the one or more operational parameters to achieve the desired operating outcome; and transmitting the generated instructions to the communications interface of the aerosol-generating apparatus, wherein the processor is configured to execute the generated instructions to adjust the at least one of the one or more operational parameters to achieve the desired operating outcome.
Upon application of a current in a first polarity, opposite faces of the piezoelectric crystal of a piezoelectric transducer respond by expanding, or bulging, outwards to define respective convex surfaces. Conversely, upon application of current in a second polarity opposite to the first polarity, the opposite faces of the piezoelectric crystal of the transducer respond by contracting, or drawing, inwards to define respective concave surfaces. In the context of an aerosol-generating apparatus, driving the piezoelectric transducer in the first polarity may ensure that physical contact between the transducer and the received aerosol precursor can be maintained. Maintaining this physical contact may improve the power efficiency of the inducement of cavitation in the aerosol precursor, and therefore may improve the efficiency of the generation of the aerosol. To this end, the driving signal may be a direct current signal to ensure driving of the piezoelectric transducer is carried out in a single polarity.
In some examples, the aerosol precursor may be a liquid aerosol precursor. In other words, the aerosol precursor may be in liquid form. Alternatively, the aerosol precursor may be a gel aerosol precursor - i.e., the aerosol may be in gel form.
In some examples, the present disclosure may be embodied in the form of an application installed on a personal user device of a user of the aerosol generating apparatus. For example, the method may be carried out by execution of an application (and e.g., user interaction with an application programming interface (API)) on a user device such as a mobile phone, laptop, computer, smartwatch, or other suitably programmable device. The user device may be communicatively connectable to the aerosol-generating apparatus by any suitable means including, for example, any suitable form of wireless communication such as Bluetooth, BLE (Bluetooth Low Energy), or Wi-Fi.
The data indicative of the one or more operational parameters may include contemporary operating data obtained from the aerosol-generating apparatus via the communications interface. Such data may include, for example, a power level of a power source (e.g., a battery) of the aerosol generating apparatus, one or more driving parameters associated with the driving of the piezoelectric transducer, an amount of aerosol precursor stored in the storage portion (e.g., a volume of aerosol precursor in a tank, optionally contained within a removable consumable), and/or personal usage statistics indicative of a user's use of that aerosol-generating apparatus.
Additionally or alternatively, the data indicative of the one or more operational parameters may include parameter-metadata. This metadata may include, for example, device metadata indicative of typical operating parameters for a particular make/model of aerosol-generating apparatus; control metadata indicative of a set of one or more operational parameters that can be controllably adjusted for a particular make/model of aerosol-generating apparatus; and/or population usage statistics indicative of an average or typical usage patter of a particular make/model of aerosol-generating apparatus. Makes and/or models of aerosol-generating apparatus may be grouped such that metadata associated with similar aerosol-generating apparatuses all contributed to the parameter-metadata. The parameter-metadata may optionally be stored on the user device and/or may be retrievable from a third party device or third party server - for example as part of an application update and/or a database lookup and retrieval method.
Additionally or alternatively, the data indicative of the one or more operational parameters may include contextual user data, e.g., biometric data. This biometric data may include, for example, a body temperature of the user, a pH and/or quantity of user saliva, user breath rate, composition of user breath, user blood pressure, and/or user heart rate. This biometric data may be used to generate instructions that cause the aerosol generating apparatus to improve the user experience e.g., to operate in a way that is less strenuous for the user, thereby reducing their heart rate/breath rate/blood pressure; or to operate in a way that provides a more desirable aerosol formulation in response to a measured saliva pH.
In some examples, receiving the user input may involve presenting the user, e.g., via a display of the user device, with a user interface (for example, a graphical user interface (GUI)) that provides the user with the option to respond to one or more prompts or to identify/select a desired user experience when using the aerosol-generating apparatus. The desired user experience may be referred to herein interchangeable as a desired operating outcome, a target operating mode, a target operating outcome, or a target user experience.
Generating the instructions may involve, for example, determining, based on the received data, how the one or more operational parameters of the aerosol-generating apparatus need to be adjusted to achieve the desired operating outcome, and generating instructions that cause those determined adjustments to be affected when the instructions are executed.
In some examples, receiving the data indicative of the one or more operational parameters includes one or more of: receiving at least some of the data from the aerosol-generating apparatus via the communications interface, and downloading at least some of the data from an application device or application server.
In some examples, the application device or application server may be maintained by or on behalf of a manufacturer or provider of the aerosol-generating apparatus.
In some examples, the generated instructions may be further suitable for causing the user device to display one or more reminders and/or alerts to the user to prompt the user to adjust their use of the aerosol-generating apparatus.
In other words, while some of the generated instructions may be transmitted to the aerosol-generating apparatus for execution by the processor, others of the generated instructions may be executed on the user device to provide the user with feedback and/or prompts to carry out actions.
In some examples, the one or more reminders and/or alerts may be based on a set of user preferences provided by the user as part of the received user input.
In some examples, the instructions for causing the aerosol-generating apparatus to automatically adjust at least one of the one or more operational parameters in response to a predetermined criterion being satisfied.
In other words, one or more of the generated instructions may be conditional instructions suitable for triggering an automatic response by the aerosol generating apparatus in response to a predetermined condition being satisfied.
For example, the instruction may prompt the aerosol-generating apparatus to modify one of the one or more operational parameters in response to a user's session length (i.e., the duration of time for which the aerosol-generating apparatus is being actively operated) to ensure that the user experience over the course of the session is maintained/improved. In some examples, after a maximum session length threshold has been exceeded, a conditional instruction may cause the aerosol-generating apparatus to disable itself.
In some examples, the method may further comprise: receiving, at the user device, personal usage statistics indicative of a usage pattern of the aerosol-generating apparatus by the user.
In this way, a user device (including e.g., an application installed thereon) may be able to take a particular user's usage patterns into account. This may involve the application learning (e.g., through implementation of an appropriately trained machine learning algorithm trained to identify usage patterns) patterns in the user's usage behaviour of the aerosol-generating apparatus.
In some examples, the personal usage statistics may be received from the aerosol-generating apparatus via the communications interface.
In some examples, the method may further comprise: receiving, at the user device, population usage statistics indicative of an average usage pattern of same or similar aerosol-generating apparatuses across a population of users.
In this way, a user device (including e.g., an application installed thereon) may be able to take an average usage pattern into account. This may involve the application effectively learning (e.g., through implementation of an appropriately trained machine learning algorithm trained to identify usage patterns) patterns in average/typical usage behaviours of the aerosol-generating apparatus.
In some examples, the population usage statistics may be received/downloaded from an application device or application server. This download may be carried out on-demand and/or may be part of a scheduled updated of the application.
In some examples, the generated instructions may cause the processor to adjust a driving signal (defined by one or more driving parameters) used to drive the piezoelectric transducer to as to change one or more of the one or more driving parameters in order to produce the desired operating outcome.
In other words, the instructions may facilitate the dynamic adjustment of the driving parameters used to drive a piezoelectric transducer in order to generate a target, or desired, response of the piezoelectric transducer to the driving signal.
Put another way, the methods described herein provide a mechanism for controllably tuning the driving signal for driving a piezoelectric transducer in order to produce a target, or optimal, response of the piezoelectric transducer, which may be an electrical response or a mechanical response, to the driving signal.
Piezoelectric transducers require a combination of interrelated driving parameters in order to be driven at an optimal efficiency. Each of the driving parameters has an effect on each of the other driving parameters, meaning that tuning a driving signal for driving a piezoelectric transducer in an optimal manner is a complex task as an adjustment to any of the driving parameters will have a knock-on effect on the remaining driving parameters.
In the context of an aerosol generating apparatus, producing a target response in the piezoelectric transducer may result in a target aerosol generation parameter being met, for example, a target aerosol volume or a target aerosol droplet size within the generated aerosol.
By adjusting the driving signal to change one or more of the driving parameters, the driving of the piezoelectric transducer may be adjusted in order to meet or maintain one or more target aerosol generation parameters.
In some examples, the driving parameters comprise: a driving frequency; and a driving duty cycle.
In this way, the driving signal may be adjusted to produce the target response of the piezoelectric transducer by adjusting the driving frequency of the driving signal, the driving duty cycle of the driving signal or a combination of both the driving frequency and the driving duty cycle.
By controllably adjusting, or tuning, the driving frequency at which the driving signal drives the piezoelectric transducer, one or more properties of the aerosol generated by the aerosol generating apparatus may be controllably adjusted - e.g., according to a user's preference, manufacturer/provider's recommendation, and/or regulatory requirement. Adjusting the driving frequency may be particularly suitable for adjusting an average size of droplets of the aerosol precursor entrained in the generated aerosol and/or a distribution of the size of said droplets. The inventors have observed that the frequency of the driving signal is a parameter that directly affects the average size of droplets in the aerosol generated by the aerosol generating apparatuses described herein. In particular, when driving the piezoelectric transducer with a driving signal having a relatively higher driving frequency, a relatively smaller average droplet size is observed. This observation is consistent with the physical mechanism for cavitation described in Kooij et al. Sci. Rep., 9, 6128 (2019), the entirety of which is incorporated herein by reference.
The driving frequency of a piezoelectric transducer has a direct effect on the efficiency of the driving of the piezoelectric transducer. In particular, the most efficient driving point of a given piezoelectric transducer is the resonant frequency of the piezoelectric transducer. Resonant frequencies are understood to be the frequency where a medium, such as a piezoelectric crystal within a piezoelectric transducer, vibrates at the highest amplitude for a given input power.
Thus, in the context of an aerosol generating apparatus, a piezoelectric transducer driven with a driving frequency equal to the resonant frequency of the piezoelectric transducer will produce more aerosol than a piezoelectric transducer driven with a driving frequency not equal to the resonant frequency of the piezoelectric transducer for the same input power.
However, during the lifetime of a piezoelectric transducer, the resonant frequency of said piezoelectric transducer may shift over time. Such a shift in resonant frequency may occur on a short-term scale, for example due to the piezoelectric transducer heating up during a single usage session, and may also occur on a long-term scale, for example where the resting resonance frequency (i.e., the resonance frequency of the piezoelectric transducer when it is not in use) changes over time due to material fatigue.
Accordingly, the received data indicative of the one or more operational parameters may also provide a means of tracking a change in a resonant frequency of a piezoelectric transducer over time such that the generated instructions may be executed to adjust the driving signal used to drive the piezoelectric transducer, and in particular adjust the driving frequency used to drive the piezoelectric transducer, in order to drive the piezoelectric transducer at the changed resonant frequency. In this way, the operation of the aerosol-generating apparatus may be adapted to produce the target response of the piezoelectric transducer to the driving signal even as the optimal driving parameters for a given piezoelectric transducer change over time.
By controllably adjusting, or tuning, the driving duty cycle at which the driving signal drives the piezoelectric transducer, one or more properties of the aerosol generated by the aerosol generating apparatus may be controllably adjusted - e.g., according to a user's preference, manufacturer/provider's recommendation, and/or regulatory requirement. Adjusting the driving duty cycle may be particularly suitable for adjusting an amount of aerosol generated by a piezoelectric transducer.
The duty cycle of a signal is understood to be the fraction of one period in which a signal is active, the period being the time period for a signal to complete an on-off cycle. For example, a driving duty cycle of 50% will have a portion of the period where the driving signal is active, and is being applied to the piezoelectric transducer, and an equal period where the driving signal is inactive, an no signal is being applied to the piezoelectric transducer.
Conventionally, it has been assumed that a higher driving duty cycle would result in a larger amount of aerosol being generated by a piezoelectric transducer. However, the inventors have observed that this is not necessarily the case.
In the example where the driving signal is a direct current signal, the timing at which the direct current signal is turned on and off, i.e., the driving duty cycle, will affect the frequency components present in the driving signal. For example, a duty cycle of 50% may include frequency components that would not be present for a duty cycle of 40%. The reduction of such additional frequency components may prevent, or minimise, destructive interference between the driving frequency and the additional frequency components, thereby leading to an increase in driving efficiency of the piezoelectric transducer.
In particular, the response of the piezoelectric transducer to the driving signal may include partial oscillations of the piezoelectric transducer. If the driving signal is cut off, due to the duty cycle, partway through one of these partial oscillations, the resulting frequency components from the partial oscillations may interfere with the driving frequency and reduce the efficiency of the piezoelectric transducer.
Therefore, the duty cycle may be adjusted, or tuned, to turn off the driving signal at a node of one of the oscillations, minimizing or eliminating the additional frequency components.
Therefore, a desired increase in the amount of aerosol being generated may be achieved by either an increase in the driving duty cycle or by a targeted decrease in the driving duty cycle to eliminate destructive frequency components in the driving signal.
Accordingly, the received data indicative of the one or more operational parameters may also provide a means of determining and tracking an optimal driving duty cycle for achieving the target response of the piezoelectric transducer.
The driving frequency and the driving duty cycle are interdependent driving parameters for driving the piezoelectric transducer. Put another way, different driving frequencies may have different optimal driving duty cycles. Accordingly, a change in the driving frequency may require a corresponding change in the driving duty cycle in order to produce the target response of the piezoelectric transducer to the driving signal.
Accordingly, the received data indicative of the one or more operational parameters may also provide a means of determining and tracking an optimal combination (to be encoded in the generated instructions) of driving frequency and driving duty cycle for achieving the target response of the piezoelectric transducer.
In particular, if the resonant frequency of the piezoelectric transducer is tracked as it changes over the piezoelectric transducer's lifetime, the corresponding optimal duty cycle for driving the piezoelectric transducer at the changed resonant frequency may also be tracked.
In some examples, the generated instructions for adjusting the driving signal to change one or more of the driving parameters may include instructions for: varying the driving frequency; measuring a response of the piezoelectric transducer to the variation of the driving frequency; and determining an optimal driving frequency based on a comparison of the response of the piezoelectric transducer to the variation of the driving frequency and the target response of the piezoelectric transducer to the driving signal.
For example, determining the optimal driving frequency may involve identifying one of the resonant frequencies of the piezoelectric transducer by identifying a maximum amplitude in the piezoelectric transducer's response. Identifying the maximum amplitude in the response of the piezoelectric transducer to the driving signal may involve determining a maximum amplitude in the voltage response of the piezoelectric transducer (i.e., the maximum voltage drop across the piezoelectric transducer). Alternatively, identifying the maximum amplitude may involve determining a maximum amplitude in the current response of the piezoelectric transducer (i.e., the maximum current flow through the piezoelectric transducer).
Alternatively, identifying one of the resonant frequencies of the piezoelectric transducer may involve identifying a minimum amplitude in the impedance response of the piezoelectric transducer (i.e., the minimum impedance - as a function of driving frequency - of the piezoelectric transducer). The minimum amplitude in the impedance response of the piezoelectric transducer may be identified by measuring the impedance response of a component connected in series with the piezoelectric transducer in order to minimize the change in behaviour of the piezoelectric transducer as a result of connecting electrical components to the piezoelectric transducer.
Different piezoelectric transducers may have different dimensions and/or be formed from materials having different compositions and/or structures. As such, different piezoelectric transducers may have different resonant frequencies. Further, over time of use, the resonant frequency/frequencies of a piezoelectric transducer may shift as discussed above, for example, as the material degrades, ages or erodes.
As such, it may be beneficial to identify a piezoelectric transducer's resonant frequency (e.g., the fundamental resonant frequency) as the optimal driving frequency, and to track the piezoelectric transducer's resonant frequency over time, to ensure that the piezoelectric transducer is driven, and continues to be driven, with a driving frequency that ensures an efficient generation of aerosol.
In some examples, generated instructions for adjusting the driving signal to change one or more of the driving parameters may include instructions for: varying the driving duty cycle; measuring a response of the piezoelectric transducer to the variation of the driving duty cycle; and determining an optimal driving duty cycle based on the response of the piezoelectric transducer to the variation of the driving duty cycle and the target response of the piezoelectric transducer to the driving signal.
For example, determining the optimal driving duty cycle may involve identifying a duty cycle that produces a maximum amplitude in the piezoelectric transducer's response. Identifying the maximum amplitude in the response of the piezoelectric transducer to the driving signal may involve determining a maximum amplitude in the voltage response of the piezoelectric transducer (i.e., the maximum voltage drop across the piezoelectric transducer). Alternatively, identifying the maximum amplitude may involve determining a maximum amplitude in the current response of the piezoelectric transducer (i.e., the maximum current flow through the piezoelectric transducer).
In some examples, generated instructions for adjusting the driving signal to change one or more of the driving parameters may include instructions for: varying both the driving frequency and the driving duty cycle; measuring a response of the piezoelectric transducer to the variation of the driving frequency and the driving duty cycle; and determining an optimal combination of driving frequency and driving duty cycle based on the response of the piezoelectric transducer to the variation of the driving frequency and the driving duty cycle and the target response of the piezoelectric transducer to the driving signal.
For example, determining the optimal combination of driving frequency and driving duty cycle may comprises the steps for determining the optimal driving frequency, i.e., the resonant frequency, as outlined above, followed by the steps for determining the optimal duty cycle for the determined optimal driving frequency, as outlined above.
In some examples, the driving parameters further comprises a driving power. By controllably adjusting, or tuning, the driving power at which the driving signal drives the piezoelectric transducer, one or more properties of the aerosol generated by the aerosol generating apparatus may be controllably adjusted - e.g., according to a user's preference, manufacturer/provider's recommendation, and/or regulatory requirement. Adjusting the driving power may be particularly suitable for adjusting an amount of aerosol generated by a piezoelectric transducer.
The driving frequency, the driving duty cycle and the driving power are all interdependent driving parameters for driving the piezoelectric transducer. Put another way, different driving frequencies may have different optimal driving duty cycles and different optimal driving powers. Accordingly, a change in the driving frequency may require a corresponding change in the driving duty cycle and/or the driving power in order to produce the target response of the piezoelectric transducer to the driving signal.
Accordingly, the received data indicative of the one or more operational parameters may provide a means of determining and tracking an optimal combination of driving frequency, driving duty cycle and driving power for achieving the target response of the piezoelectric transducer.
In some examples, instructions for adjusting the driving signal to change one or more of the driving parameters may include instructions for: varying the driving frequency, the driving duty cycle and the driving power; measuring a response of the piezoelectric transducer to the variation of the driving frequency, the driving duty cycle and the driving power; and determining an optimal combination of driving frequency, driving duty cycle and driving power based on the response of the piezoelectric transducer to the variation of the driving frequency, the driving duty cycle and the driving power and the target response of the piezoelectric transducer to the driving signal.
For example, determining the optimal combination of driving frequency and driving duty cycle may comprises the steps for determining the optimal driving frequency, i.e., the resonant frequency, as outlined above, followed by the steps for determining the optimal duty cycle for the determined optimal driving frequency, as outlined above.
The optimal driving power for the determined optimal driving frequency and determined optimal driving duty cycle may then be determined. Determining the optimal driving power may involve identifying a driving power that produces a maximum amplitude in the piezoelectric transducer's response. Identifying the maximum amplitude in the response of the piezoelectric transducer to the driving signal may involve determining a maximum amplitude in the voltage response of the piezoelectric transducer (i.e., the maximum voltage drop across the piezoelectric transducer). Alternatively, identifying the maximum amplitude may involve determining a maximum amplitude in the current response of the piezoelectric transducer (i.e., the maximum current flow through the piezoelectric transducer).
In some examples, the aerosol generating apparatus further comprises a memory adapted to store a last known set of optimal driving parameters. In this case, the data received from the aerosol-generating apparatus as part of the methods described herein may include the last known set of optimal driving parameters. The generated instructions may consequently include instructions for varying each of the one or more driving parameters about each of the last known set of optimal driving parameters; measuring a response of the piezoelectric transducer to the variation of each of the driving parameters about the last known set of optimal driving parameters; determining an updated set of optimal driving parameters based on the response of the piezoelectric transducer to the variation of each of the driving parameters; and updating the last known set of optimal driving parameters stored on the memory with the updated set of optimal driving parameters.
In this way, the process of determining the set of optimal driving parameters may begin from a best known starting point of the previous set of optimal driving parameters. In this way, the aerosol-generating apparatus is more likely to arrive at the updated set of optimal driving parameters in a shorter period of time, thereby improving the efficiency of optimising the driving parameters for driving the piezoelectric transducer.
In some examples, the aerosol generating apparatus further comprises an inhalation sensor adapted to sense an inhalation of a user. The received data indicative of the one or more operational parameters may further include inhalation data indicative of inhalation patterns of the user. In some examples, the generated instructions may include a conditional instruction that causes the generation of the driving signal in response to the inhalation of the user. In this way, the device may operate automatically in response to an inhalation by the user without requiring a separate user input.
In some examples, the inhalation of the user occurs over an inhalation period. In such examples, the generated instructions may include instructions for adjusting the driving signal during an adjustment period within the inhalation period. In this way, the device may perform the process of optimising the driving parameters when the piezoelectric transducer is already being driven in response to an inhalation of the user, rather than requiring the user to perform a separate optimization process.
In some examples, the generated instructions may include one or more conditional instructions for adjusting the driving signal in response to each inhalation of the user. In this way, the device may regularly update the optimal set of driving parameters in order to maximise the time that the aerosol generating apparatus is operating in an efficient manner.
In some examples, the data indicative of the one or more operational parameters may include data received from the aerosol-generating apparatus that is indicative of an amount of aerosol precursor that is in contact with the piezoelectric transducer.
In other words, there is provided a means of identifying an amount (including a lack, or absence) of aerosol precursor in contact with the piezoelectric transducer based on the driving parameters for driving the piezoelectric transducer.
For a given piezoelectric transducer, the driving parameters for driving the piezoelectric transducer at an optimal frequency will typically sit within an expected range of driving parameters required to drive the piezoelectric transducer. The expected range of driving parameters may depend on the target response of the piezoelectric transducer as well as the manufacturing parameters and tolerances of the piezoelectric transducer.
The expected parameter range for the driving frequency, i.e., the expected frequency range of the piezoelectric transducer, may also correspond to an expected, or desired, range of frequencies centred on the resonance frequency of the piezoelectric transducer.
An expected parameter range for the driving duty cycle, i.e., the expected duty cycle range of the piezoelectric transducer, may correspond to an expected, or desired, amount of aerosol produced.
Should the aerosol generating apparatus need to adjust one or more of the driving parameters such that the one or more driving parameters would lie outside of the expected range of driving parameters, it may be determined, based on the received data that a problem may be occurring within the aerosol generating apparatus, and in particular that the piezoelectric transducer is not receiving enough liquid aerosol precursor.
If the piezoelectric transducer were to be driven in an attempt to generate aerosol in the absence of sufficient liquid aerosol precursor, a so-called "dry hit" event, the piezoelectric transducer may become damaged and cease to function correctly. By identifying a dry hit by recognising the need to adjust one or more of the driving parameters such that the one or more driving parameters would lie outside of the expected range of driving parameters, the aerosol generating apparatus may prevent the piezoelectric transducer from being driven, thereby preventing damage to the piezoelectric transducer.
In some examples, the generated instructions may include a conditional instruction for disabling the aerosol-generating apparatus in response to the identification of a dry hit event.
In some examples, the generated instructions may include instructions for determining whether the driving signal can be adjusted to produce the target response of the piezoelectric transducer to the driving signal that include instructions for: varying the driving frequency within an expected frequency range; measuring a response of the piezoelectric transducer to the variation of the driving frequency within the expected frequency range; comparing the measured response of the piezoelectric transducer to the target response of the piezoelectric transducer; and determining whether the driving signal can be adjusted to produce the target response of the piezoelectric transducer by changing the driving frequency within the expected frequency range.
For example, determining an optimal driving frequency may involve identifying one of the resonant frequencies of the piezoelectric transducer by identifying a maximum amplitude in the piezoelectric transducer's response. Identifying the maximum amplitude in the response of the piezoelectric transducer to the driving signal may involve determining a maximum amplitude in the voltage response of the piezoelectric transducer (i.e., the maximum voltage drop across the piezoelectric transducer). Alternatively, identifying the maximum amplitude may involve determining a maximum amplitude in the current response of the piezoelectric transducer (i.e., the maximum current flow through the piezoelectric transducer).
Alternatively, identifying one of the resonant frequencies of the piezoelectric transducer may involve identifying a minimum amplitude in the impedance response of the piezoelectric transducer (i.e., the minimum impedance - as a function of driving frequency - of the piezoelectric transducer). The minimum amplitude in the impedance response of the piezoelectric transducer may be identified by measuring the impedance response of a component connected in series with the piezoelectric transducer in order to minimize the change in behaviour of the piezoelectric transducer as a result of connecting electrical components to the piezoelectric transducer.
The maximum amplitude in the piezoelectric transducer's response, or the minimum amplitude in the impedance response of the piezoelectric transducer, may be the target response of the piezoelectric transducer to the driving signal.
If the variation of the driving frequency within the expected frequency range does not yield the target response of the piezoelectric transducer to the driving signal, it may be determined that the driving signal cannot be adjusted to produce the target response of the piezoelectric transducer and so it may be determined that insufficient aerosol precursor is in contact with the piezoelectric transducer.
In some examples, instructions for determining whether the driving signal can be adjusted to produce the target response of the piezoelectric transducer to the driving signal may include instructions for: varying the driving duty cycle within an expected duty cycle range; measuring a response of the piezoelectric transducer to the variation of the driving duty cycle within the expected duty cycle range; comparing the measured response of the piezoelectric transducer to the target response of the piezoelectric transducer; and determining whether the driving signal can be adjusted to produce the target response of the piezoelectric transducer by changing the driving duty cycle within the expected duty cycle range.
For example, determining the optimal driving duty cycle may involve identifying a duty cycle that produces a maximum amplitude in the piezoelectric transducer's response. Identifying the maximum amplitude in the response of the piezoelectric transducer to the driving signal may involve determining a maximum amplitude in the voltage response of the piezoelectric transducer (i.e., the maximum voltage drop across the piezoelectric transducer). Alternatively, identifying the maximum amplitude may involve determining a maximum amplitude in the current response of the piezoelectric transducer (i.e., the maximum current flow through the piezoelectric transducer).
The maximum amplitude in the piezoelectric transducer's response may be the target response of the piezoelectric transducer to the driving signal.
If the variation of the driving duty cycle within the expected duty cycle range does not yield the target response of the piezoelectric transducer to the driving signal, it may be determined that the driving signal cannot be adjusted to produce the target response of the piezoelectric transducer and so it may be determined that insufficient aerosol precursor is in contact with the piezoelectric transducer.
In some examples, instructions for determining whether the driving signal can be adjusted to produce the target response of the piezoelectric transducer to the driving signal may include instructions for: varying both the driving frequency and the driving duty cycle within an expected frequency range and within an expected duty cycle range, respectively; measuring a response of the piezoelectric transducer to the variation of the driving frequency and the driving duty cycle; comparing the measured response of the piezoelectric transducer to the target response of the piezoelectric transducer; and determining whether the driving signal can be adjusted to produce the target response of the piezoelectric transducer by changing the driving frequency within the expected frequency range and/or by changing the driving duty cycle within the expected duty cycle range.
For example, determining whether the driving frequency can be adjusted within the expected frequency range and driving duty cycle can be adjusted within the expected duty cycle range to produce the target response of the piezoelectric transducer may comprise the steps for determining whether the driving signal can be adjusted to produce the target response of the piezoelectric transducer by changing the driving frequency, as outlined above, followed by the steps for determining whether the driving signal can be adjusted to produce the target response of the piezoelectric transducer by changing the driving duty cycle, as outlined above.
For example, determining whether the driving frequency can be adjusted within the expected frequency range and driving duty cycle can be adjusted within the expected duty cycle range to produce the target response of the piezoelectric transducer may comprise the steps for determining whether the driving signal can be adjusted to produce the target response of the piezoelectric transducer by changing the driving frequency, as outlined above, followed by the steps for determining whether the driving signal can be adjusted to produce the target response of the piezoelectric transducer by changing the driving duty cycle, as outlined above. The aerosol generating apparatus may then determine whether the driving power can be adjusted within the expected power range to produce the target response of the piezoelectric transducer.
In some examples, generated instructions may be suitable for determining whether the driving signal can be adjusted to produce the target response of the piezoelectric transducer to the driving signal within the inhalation period. In this way, the process of determining whether insufficient aerosol precursor is in contact with a piezoelectric transducer may be performed before the piezoelectric transducer is driven in response to an inhalation of the user, rather than requiring the user to perform a separate checking process but before the piezoelectric transducer is driven in the absence of sufficient aerosol precursor.
In some examples, the generated instructions may be suitable for determining whether the driving signal can be adjusted to produce the target response of the piezoelectric transducer to the driving signal in response to each inhalation of the user. In this way, the device may regularly check that sufficient aerosol precursor is in contact with the piezoelectric transducer in order to minimise the risk of driving the piezoelectric transducer in the absence of aerosol precursor.
In some examples at least some of the received data indicative of the one or more operational parameters is received from a cartridge memory unit installed in a replaceable cartridge of the aerosol generation apparatus. The cartridge memory unit may be adapted to store one or more of: a set of one or more operational parameters of the piezoelectric transducer, and/or an inhalation metric associated with the piezoelectric transducer.
In other words, there is provided a replaceable cartridge with a memory unit for receiving and storing driving parameters for driving the aerosol generating unit in the cartridge.
Put another way, the driving parameters for driving an aerosol generating unit may be stored locally within a memory on the cartridge itself.
By providing an on-cartridge memory unit the present disclosure provides a means of storing the driving parameters for driving and aerosol generating unit in the same, removable, part of the system as the aerosol generating unit itself. In this way, should the replaceable cartridge be separated from a given aerosol generating device and inserted into a different aerosol generating device, the aerosol generating unit can still be driven using the same stored driving parameters in order to maintain consistent aerosol delivery from the replaceable cartridge.
The cartridge memory unit may store a driving frequency of the piezoelectric transducer. By storing the driving frequency, and in particular an optimal driving frequency, locally to the piezoelectric transducer it may be ensured that the piezoelectric transducer is driven at the optimal driving frequency, such as the resonant frequency of the piezoelectric transducer, rather than having to identify the optimal driving frequency of the piezoelectric transducer each time it is driven or provided to a new aerosol generating device.
The cartridge memory unit may further store a tracked change in a resonant frequency of a piezoelectric transducer. This tracked change may be received as part of the data indicative of the one or more operational parameters of the aerosol-generating apparatus.
The cartridge memory unit may further store a driving duty cycle associated with the piezoelectric transducer. By storing the driving duty cycle, and in particular an optimal driving duty cycle, locally to the piezoelectric transducer it may be ensured that the piezoelectric transducer is driven at the optimal driving duty cycle, such as the duty cycle that minimizes or eliminates the additional frequency components in the response of the piezoelectric transducer to the driving signal, rather than having to identify the optimal driving duty cycle of the piezoelectric transducer each time it is driven or provided to a new aerosol generating device.
By storing both the driving frequency and the driving duty cycle locally to the piezoelectric transducer it may be ensured that the piezoelectric transducer is driven at the optimal combination of driving frequency and driving duty cycle, rather than having to identify the optimal combination of driving frequency and driving duty cycle of the piezoelectric transducer each time it is driven or provided to a new aerosol generating device.
The cartridge memory unit may further store a driving power associated with the piezoelectric transducer. By storing the driving power, and in particular an optimal driving power, locally to the piezoelectric transducer it may be ensured that the piezoelectric transducer is driven at the optimal driving power, such as the power that minimizes or eliminates the additional frequency components in the response of the piezoelectric transducer to the driving signal, rather than having to identify the optimal driving power of the piezoelectric transducer each time it is driven or provided to a new aerosol generating device.
By storing the driving frequency, the driving duty cycle and the driving power locally to the piezoelectric transducer it may be ensured that the piezoelectric transducer is driven at the optimal combination of driving frequency, driving duty cycle and driving power, rather than having to identify the optimal combination of driving frequency, driving duty cycle and driving power of the piezoelectric transducer each time it is driven or provided to a new aerosol generating device.
In some examples, a metric of the inhalations a user has performed with a given replaceable cartridge may be stored locally within a memory on the cartridge itself.
The on-cartridge memory unit provides a means of storing the inhalation metrics in the same, removable, part of the system as the components that are directly affected, or depleted, by user inhalations (such as the aerosol generating unit). In this way, should the replaceable cartridge be separated from a given aerosol generating device and inserted into a different aerosol generating device, the metrics associated with inhalations performed using the given replaceable pod can still be utilized by the aerosol generating device to monitor an aspect of the replaceable cartridge accurately. In some examples, the inhalation metric may include one or more of: an inhalation count based on a number of inhalations detected by the sensor and/or a determined aerosol generation efficiency for each inhalation.
By generating the inhalation metric as a combination of inhalation count and aerosol generation efficiency, the device may more accurately determine the consumption of aerosol and aerosol precursor by the user, as opposed to a plain inhalation count. Accordingly, information about the user's consumption may be more accurately derived and the remaining amount of aerosol precursor in the replaceable cartridge may be more accurately tracked.
In some examples, the generated instructions may include a conditional instruction for prompting the user to replace a depleted cartridge and/or disabling the aerosol-generating apparatus in response to the inhalation metric falling below an inhalation metric threshold.
In some examples, the received data indicative of the one or more operating parameters may further include a drive count based on a number of driving signals sent to the piezoelectric transducer. The generated instructions may include instructions for monitoring the driving of the aerosol generating unit to determine a driving period for each driving signal; and generating the drive metric update based on the drive count and the aerosol driving period.
In this way, a more accurate indication of the fatigue of the piezoelectric transducer over time may be generated. For example, if a piezoelectric transducer were to be assumed to be exhausted after 100 two second inhalations, an aerosol generating device monitoring only inhalation count may assume that the piezoelectric transducer is empty after 100 inhalations of any length. However, if each inhalation were to only be one second in duration, then in fact the piezoelectric transducer would not be exhausted and could continue to be used. Alternatively, if each inhalation were to be four seconds in duration, then in fact the piezoelectric transducer would be exhausted after 50 inhalations. Accordingly, by accounting for the driving period, the monitoring of the state of the piezoelectric transducer may be made more accurate.
In some examples, the generated instructions may be suitable for causing the provision of a surface priming signal to drive the piezoelectric transducer so as to expel excess aerosol precursor from the aerosolizing surface of the piezoelectric transducer.
One or more parameters of the aerosol precursor may impact one or more parameters of the aerosol generated by the aerosol generating apparatuses described herein.
The density, viscosity, volume and molecular size of aerosol precursor on the surface of a piezoelectric transducer may each affect the performance (e.g., the vibratory response) of said piezoelectric transducer in terms of the parameters of the generated aerosol. The physical properties of the aerosol precursor that is in physical contact with the surface of the piezoelectric transducer contribute to the overall mechanical/physical structure of the transducer meaning that variations in the density and volume of the aerosol precursor may (slightly) shift the resonance frequency/frequencies of the piezoelectric transducer. Moreover, changes in the volume of aerosol precursor on the surface of the piezoelectric transducer may change the distance that a cavitation shock must propagate through the aerosol precursor to induce filamentation and consequently aerosolization. As such, changes in both the volume and density of the aerosol precursor can alter the parameters of the generated aerosol.
Similarly, changes in the viscosity of the aerosol precursor affect the fluidic properties of the aerosol precursor, in particular the inertial response of the aerosol precursor to the vibrations of the piezoelectric transducer. This consequently influences the extent (and size) of cavitation within the aerosol precursor, and the propagation of the cavitation shock through the aerosol precursor. As such, changes in the viscosity alter the parameters of the generated aerosol.
The molecular size of the aerosol precursor may correlate with the average droplet size in the generated aerosol.
The one or more parameters of the generated aerosol that may be affected by these parameters of the aerosol precursor may include one or more of: an amount of aerosol precursor entrained in the generated aerosol for each puff of the aerosol generating apparatus in use; an average size of the droplets of aerosol precursor entrained in the generated aerosol; and/or a distribution of the size of the droplets of aerosol precursor entrained in the generated aerosol.
Density, viscosity, and molecular size may be considered to be intrinsic properties of the aerosol precursor. As such, modifying the density, viscosity and molecular size of the aerosol precursor may require modifying the composition of the precursor itself.
In contrast, the volume of the aerosol precursor on the surface of the piezoelectric transducer may be considered to be an extrinsic property of the received aerosol precursor. That is, the amount of aerosol precursor on the surface of the piezoelectric transducer (i.e., the volume of the received aerosol precursor) may be controlled by a user of the aerosol generating apparatuses described herein. Aerosol precursor may be received onto the surface of the piezoelectric transducer to increase the volume of aerosol precursor on the surface of the piezoelectric transducer.
However, it is also possible that, during use of an aerosol generating apparatus, excess aerosol precursor may build up on the surface of the piezoelectric transducer. Such an excess an excess may negatively impact the performance of the piezoelectric transducer and consequently the aerosol generating apparatus.
As such, providing a surface priming signal for the purpose of expelling excess aerosol precursor from the surface of the piezoelectric transducer may improve the performance of the piezoelectric transducer and consequently the aerosol generating apparatus.
The surface priming signal may be a signal that, when the piezoelectric transducer is driven in accordance with the surface priming signal, causes the piezoelectric transducer to vibrate with an amplitude that is sufficient to expel a portion (e.g., the excess portion) of the received aerosol precursor from the surface of the piezoelectric transducer. In this way, driving the piezoelectric transducer with the surface priming signal may facilitate control of one or more parameters of the aerosol generated by the piezoelectric transducer, thereby improving the user experience for a user of the aerosol generating apparatuses described herein.
In some examples, driving the piezoelectric transducer to expel excess aerosol precursor from the surface of the piezoelectric transducer may further expel excess aerosol precursor from at least a portion of a wick of the aerosol generating apparatus. The wick may be arranged to convey the aerosol precursor from the tank to the piezoelectric transducer.
In addition to excess aerosol precursor building up on the surface of the piezoelectric transducer, when the aerosol precursor is conveyed to the surface of the piezoelectric transducer from the tank via a wick, excess aerosol precursor may build up in the structure of the wick.
The wick may be formed from any material suitable for wicking aerosol precursor from the tank to the surface of the piezoelectric transducer. For example, the wick may be formed from any suitable fibrous material such as, but not limited to, cotton or bamboo fibres.
Expelling excess aerosol precursor from the wick may, in addition to reducing the volume of received aerosol precursor on the surface of the piezoelectric transducer, reduced the amount of aerosol precursor born in the wick and, consequently, reduce the rate of conveyance of aerosol precursor from the tank to the wick. In other words, expelling excess aerosol precursor from the wick may reduce the rate at which aerosol precursor is added to the surface of the piezoelectric transducer.
In some examples, a power level of the surface priming signal may be greater than a power level of the driving signal.
In this way, the driving signal may be suitable for inducing cavitation and one or more shocks in the received aerosol precursor to thereby generate an aerosol without inducing a bulk expulsion of precursor material from the surface of the piezoelectric transducer. Conversely, the surface priming signal may be configured and delivered with a power level sufficient to drive vibrations (or distortions/displacements) in the surface of the piezoelectric transducer that have a large enough energy and amplitude to expel, in bulk, excess aerosol precursor from the surface of the piezoelectric transducer.
In some examples, the received data indicative of the one or more operational parameters may include data obtained by monitoring, while the aerosol generating apparatus is in use, a build-up of aerosol precursor on the surface of the piezoelectric transducer, and the generated instructions may include a conditional instruction to provide the surface priming signal to drive the piezoelectric transducer in response to the aerosol precursor crossing a predetermined threshold.
In other words, when an amount of aerosol precursor builds up above a predetermined threshold, the conditional instruction may cause the provision of one or more instances of the surface priming signal (e.g., in the form of a boost signal to the driving signal) to expel the excess aerosol precursor from the surface of the piezoelectric transducer so as to maintain a particular (e.g., a preferred or desired) operating condition of the aerosol generating apparatuses described herein.
In this way, the amount of received aerosol precursor may be monitored and controllably maintained to ensure a consistent user experience for a user of the aerosol generating apparatuses described herein.
In some examples, the predetermined threshold may be one or more of: a predetermined volume of aerosol precursor on the surface of the piezoelectric transducer; a predetermined mass of aerosol precursor on the surface of the piezoelectric transducer; a volume of aerosol generated per puff of the aerosol generating apparatus, when in use; and/or a concentration of aerosol generated per puff of the aerosol generating apparatus, when in use.
Both the volume and mass of received aerosol precursor on the surface of the piezoelectric transducer may directly correlate with the amount of received aerosol precursor deposited on the surface of the piezoelectric transducer and, as such, monitoring one or both of the volume and mass of the received aerosol precursor may be a suitable indicator for the amount of build-up of excess aerosol precursor on the surface of the piezoelectric transducer.
Meanwhile, as excess aerosol precursor builds up on the surface of the piezoelectric transducer, the distance that a cavitation shock must propagate through to induce filamentation and consequently aerosolization also increases, thereby reducing the efficiency with which aerosol is generated by the aerosol generating apparatus. As such, a build-up of excess aerosol precursor on the surface of the piezoelectric transducer may reduce one or both of the amount and/or concentration of aerosol generated per puff of the aerosol generating apparatus, when in use. Accordingly, monitoring one or both of the amount and concentration of aerosol generated per puff of the aerosol generating apparatus when in use may be a suitable indicator for the amount of build-up of excess aerosol precursor on the surface of the piezoelectric transducer.
In some examples, the received data indicative of the one or more operational parameters may include data obtained by measuring a response of the piezoelectric transducer to the driving signal; and and/or a profile of the aerosol precursor that is determined based on the measured response of the piezoelectric transducer to the driving signal.
In this context, the providing of the surface priming signal may be useable as part of a wider process where the surface priming signal effectively sets (or calibrates) the aerosol generating apparatus to be in a condition from which a profile of the aerosol precursor may be determined.
Determining a profile of the aerosol precursor may be beneficial in a variety of contexts.
As discussed above, the intrinsic properties of an aerosol precursor such as viscosity, density and/or molecular size may also impact one or more parameters of the aerosol generated by the aerosol generating apparatuses described herein. As such, it may be beneficial to determine a profile of the aerosol precursor from which aerosol is being generated so as to modify one or more operational parameters of the aerosol generating apparatus (e.g., a driving frequency, driving power and/or driving duty cycle of the driving signal) to achieve one or more target parameters of the generated aerosol.
The one or more target parameters of the generated aerosol may include one or more of: an amount of aerosol precursor entrained in the generated aerosol for each puff of the aerosol generating apparatus in use; an average size of the droplets of aerosol precursor entrained in the generated aerosol; and/or a distribution of the size of the droplets of aerosol precursor entrained in the generated aerosol.
Additionally or alternatively, determining the profile of the aerosol precursor may be advantageous for determining if the aerosol precursor contained within the tank is formed from an authorised composition and/or if the tank connected to a body of the aerosol generating apparatus is an authorised tank. For example, if the aerosol precursor and/or the tank originates from an unauthorised (e.g., counterfeit) source, use of the unauthorised aerosol precursor and/or unauthorised tank may lead to one or more of: damage to the aerosol generating apparatus (e.g., due to an unsecure or overloaded electrical connection between the unauthorised tank and the body of the aerosol generating apparatus) and/or damage to a user of the aerosol generating apparatus (e.g., because a counterfeit or illicit composition in an aerosol precursor may negatively impact the health of the user).
As such, it is beneficial to be able to verify that the tank and/or aerosol precursor used in the aerosol generating apparatus is an authorised (and known) aerosol precursor and/or tank.
In some examples, determining the profile of the aerosol precursor may involve comparing the measured response of the piezoelectric transducer with one or more reference responses. Each of the one or more reference responses may correspond to a respective authorised aerosol precursor that is authorised for use with the aerosol generating apparatus. Determining the profile of the aerosol precursor may further involve verifying, based on the comparing the measured response with the one or more reference responses, whether the aerosol precursor is an authorised aerosol precursor.
The one or more reference responses may be stored in a database of responses against which a determined profile may be compared e.g., via a look-up function. The database of stored one or more reference responses may be updated on a regular, continuous or as-needed basis
Updating the database of one or more reference responses may involve receiving a new one or more reference responses to add into the database from a trusted source - e.g., a remote server maintained by a provider/manufacturer of the aerosol generating apparatuses described herein or any of the components thereof. This remote server may be the same or a different server as the one from which data indicative of the one or more operational parameters is received by/downloaded to the user device.
The database of one or more reference responses may be stored either on-board the aerosol generating apparatus e.g., in a memory thereof, or in a remote location such as on a remote device or in a remote server. Further, the operation of determining the profile of the aerosol precursor may be performed locally or remotely with respect to the aerosol-generating apparatus, either with respect to the aerosol generating apparatus or the database of one or more reference responses. In other words, the determining of the profile of the aerosol precursor may be carried out by a processor or control unit of the aerosol generating apparatus, by a computer that is locally connected to the database of one or more reference responses, or by a computer that is remote from both the aerosol generating apparatus and the database. In some examples, determining the profile of the aerosol precursor may be carried out on the user device and may be a precursor to the generation of the instructions.
In some examples, the generated instructions may include an instruction to disable the aerosol generating apparatus if it is determined that the aerosol precursor is not an authorised aerosol precursor.
In this way, damage to the aerosol generating apparatus and/or to the health of a user of the aerosol generating apparatus may be prevented.
In some examples, the generated instructions may include instructions for modifying one or more operational parameters of the aerosol generating apparatus according to stored target operational parameters associated with an authorised aerosol precursor if it is determined that the aerosol precursor is the authorised aerosol precursor.
The stored target operational parameters may be stored in a database separate from or connected to the database of reference responses. In some examples, the stored target operational parameters may be stored in the database of reference responses in any suitable format - e.g., a key-value structure wherein the target operational parameters associated with a given authorised aerosol precursor are stored as the 'value' in the key-value pair, and the profile/identity of said authorised aerosol precursor is stored as the `key' in the key-value pair.
As discussed above, in some examples, the generated instructions may be suitable for adjusting a driving frequency of the driving signal used to drive the piezoelectric transducer form an initial driving frequency to a new driving frequency. The initial driving frequency may be a resonant frequency of the piezoelectric transducer. In some such examples, changing the driving frequency from the initial driving frequency to the new driving frequency may detune the driving frequency off-resonance.
Driving a piezoelectric transducer with a driving signal having a driving frequency that matches a resonant frequency of the piezoelectric transducer improves the efficiency with which vibrations are induced in the piezoelectric transducer. As an example, for a given power input level of a driving signal, the amplitude of the vibratory response of the piezoelectric transducer will exhibit strong peaks when the driving frequency matches one of the resonant frequencies of the piezoelectric transducer with the strongest - that is, the highest amplitude - response being observable for a driving frequency that matches the fundamental (lowest-frequency) resonant frequency of the piezoelectric transducer. In the context of the present disclosure, the set of resonant frequencies of a piezoelectric transducer may be considered to consist of the fundamental resonant frequency and one or more of the harmonic frequencies of the fundamental resonant frequency (i.e., integer multiples of the fundamental resonant frequency). In some examples, a piezoelectric transducer may only exhibit resonant behaviour for odd- order harmonics. In other words, a piezoelectric transducer may only exhibit resonant behaviour for driving frequencies matching the frequency of one of the 3^rd, 5^th, 7^th, 9^th, ..., etc. harmonics.
In some examples, detuning the driving frequency off-resonance may involve adjusting the frequency of the driving signal such that the new driving frequency does not match a resonant frequency of the piezoelectric transducer but does sit within a frequency range that corresponds to a resonance peak in the behavioural response of the piezoelectric transducer. Each resonance peak in the behavioural response may be defined by a quality factor, or Q-factor, indicative of the width of the resonance peak.
The Q-factor may be understood as the ratio between the resonant frequency of the corresponding resonance peak, and the full-width-half-maximum (FWHM) of the resonance peak in frequency space. Accordingly, a larger Q-factor is indicative of a narrower resonance peak, while a smaller Q-factor is conversely indicative of a wider resonance peak. Each resonance peak of the piezoelectric transducer may therefore be understood as being defined, at least in part, by its resonant frequency and its width - whether in terms of a Q-factor or a frequency range.
In some examples the initial frequency may be part of the received data and may be determined by: providing, to the piezoelectric transducer, a scanning signal defined by an electrical signal that scans across a range of frequencies, and identifying the resonant frequency of the piezoelectric transducer based on the response of the piezoelectric transducer to the scanning signal across the range of frequencies.
For example, determining the initial frequency may involve identifying one of the resonant frequencies of the piezoelectric transducer by identifying a maximum amplitude in the piezoelectric transducer's response. Identifying the maximum amplitude may involve determining a maximum amplitude in the voltage response of the piezoelectric transducer (i.e., the maximum voltage drop across the piezoelectric transducer). Alternatively, identifying the maximum amplitude may involve determining a maximum amplitude in the current response of the piezoelectric transducer (i.e., the maximum current flow through the piezoelectric transducer). Alternatively, identifying one of the resonant frequencies of the piezoelectric transducer may involve identifying a minimum amplitude in the impedance response of the piezoelectric transducer (i.e., the minimum impedance - as a function of driving frequency - of the piezoelectric transducer).
In some examples, the initial driving frequency may be a harmonic frequency of the fundamental resonant frequency of the piezoelectric transducer.
As discussed above, in other examples, the initial driving frequency may be the fundamental resonant frequency of the piezoelectric transducer.
In some examples, the initial and/or new driving frequencies may be selected based on one or more parameters of the aerosol precursor and/or one or more target parameters of the generated aerosol.
In other words, the initial driving frequency and/or the new driving frequency may be controllably selected to provide control (e.g., to a user of the aerosol generating apparatus) over the aerosol generated by the aerosol generating apparatus, taking into account effects that one or more properties of the aerosol precursor may have on the one or more parameters of the generated aerosol.
In some examples, the generated instructions may include instructions for adjusting the driving signal so as to modify the one or more parameters of the generated aerosol based on one or more parameters of the aerosol precursor and/or one or more target parameters of the generated aerosol.
The one or more parameters to be adjusted may include the duty cycle. Adjusting the duty cycle of the driving signal facilitates control of capacitive effects (e.g., pseudo-capacitive discharge) that arise from the inherent dielectric properties of the material from which the piezoelectric transducer is formed. For example, by appropriate control/tuning of the duty cycle, these capacitive effects may be limited or even entirely eliminated so as to ensure a more precise control of the vibrations of the piezoelectric transducer, and consequently a more reliable control of the one or more parameters of the generated aerosol.
In particular, by reducing (or even eliminating) the capacitive discharge of the piezoelectric transducer, the vibratory response of the piezoelectric transducer to the driving signal can be controlled such that the oscillations of the piezoelectric transducer include a reduced number of frequency components. In a particular example, control of the duty cycle may be optimised such that the vibratory response of the piezoelectric transducer includes just a single frequency component.
As the size of droplets in the generated aerosol is primarily affected by the frequency of the vibrations of the piezoelectric transducer, controlling the duty cycle may be used to control the number of frequency components in the piezoelectric transducer's vibratory response, and consequently control the distribution of droplet sizes in the generated aerosol.
The one or more parameters to be adjusted may include a power level. nAdjusting the power level of the driving signal facilitates control of the amount of cavitation induced by the piezoelectric transducer in the aerosol precursor located on the surface of the transducer. As such, adjusting the power level of the driving signal may facilitate the control of an amount of aerosol precursor droplets entrained in the generated aerosol. In other words, controllably adjusting the power level of the driving signal facilitates control of the concentration of the generated aerosol.
In some examples, the one or more parameters of the aerosol precursor may include one or more of: a density of the aerosol precursor, a viscosity of the aerosol precursor, a volume of the received aerosol precursor, and/or a molecular size of the aerosol precursor.
In some examples, the one or more target parameters of the generated aerosol may include one or more of: an amount of aerosol precursor entrained in the generated aerosol for each puff of the aerosol generating apparatus in use; an average size of the droplets of aerosol precursor entrained in the generated aerosol; and/or a distribution of the size of the droplets of aerosol precursor entrained in the generated aerosol.
In some examples, the one or more modified parameters of the generated aerosol may include one or more of: an amount of aerosol precursor entrained in the generated aerosol for each puff of the aerosol generating apparatus in use; an average size of the droplets of aerosol precursor entrained in the generated aerosol; and/or a distribution of the size of the droplets of aerosol precursor entrained in the generated aerosol.
In some examples, the driving signal may be a first driving signal that drives the piezoelectric transducer at a first driving frequency to generate an aerosol having a first average droplet size. In such examples, the generated instructions may include instructions to provide, to the piezoelectric transducer, a second driving signal to drive the piezoelectric transducer at a second driving frequency to generate an aerosol having a second average droplet size.
The first and second driving signals may be provided to the piezoelectric transducer concurrently, simultaneously or at least partly simultaneously.
Driving the piezoelectric transducer with two different driving signals each having their respective driving frequency means it may be possible to generate an aerosol with two distinct populations of droplets (in terms of average droplet size). This may facilitate an enhanced user experience for a user of the aerosol generating apparatuses described herein. For example, the first average droplet size may be approximately 5 µm (e.g., between 4 µm and 6 µm). An aerosol comprising droplets of this size may typically be deposited in the mouth of a user so that the user is able to experience a taste sensation associated with the deposition of the droplets on the tongue of the user when they inhale the aerosol generated by the aerosol generating apparatuses herein. Meanwhile, the second average droplet size may be less than 2 µm. An aerosol comprising droplets of this size may typically be deposited in the lungs of a user so that active ingredients within those droplets may be more efficiently absorbed into the user's bloodstream, thereby enhancing the user's experience of using the aerosol generating apparatuses described herein.
In some examples, the first and second driving signals may be respectively different harmonics of the fundamental resonant frequency of the piezoelectric transducer. For the avoidance of doubt, the fundamental resonant frequency may be considered to be the first harmonic of the fundamental resonant frequency.
Driving the piezoelectric transducer with two different driving signals each having their respective driving frequency, it may be possible to generate an aerosol with two distinct populations of droplets (in terms of average droplet size). This may facilitate an enhanced user experience for a user of the aerosol generating apparatuses described herein. For example, the first average droplet size may be approximately 5 µm (e.g., between 4 µm and 6 µm). An aerosol comprising droplets of this size may typically be deposited in the mouth of a user so that the user is able to experience a taste sensation associated with the deposition of the droplets on the tongue of the user when they inhale the aerosol generated by the aerosol generating apparatuses herein. Meanwhile, the second average droplet size may be less than 2 µm. An aerosol comprising droplets of this size may typically be deposited in the lungs of a user so that active ingredients within those droplets may be more efficiently absorbed into the user's bloodstream, thereby enhancing the user's experience of using the aerosol generating apparatuses described herein.
In some examples, the second average droplet size may be smaller than the first average droplet size.
As noted elsewhere, herein, the inventors have observed that the frequency of the driving signal is a parameter that directly affects the average size of droplets in the aerosol generated by the aerosol generating apparatuses described herein.
Accordingly, in some examples, to achieve a second average droplet size that is smaller than the first average droplet size, the second driving frequency may be greater than the first driving frequency. In other words, the second driving frequency may be a higher-order harmonic of the fundamental resonant frequency of the piezoelectric transducer than the first driving frequency.
In some examples, the generated instructions may include instructions for adjusting one or both of the first and second driving frequencies.
In some examples, the initial first and second driving frequencies may be the same frequency (e.g., the fundamental resonant frequency of the piezoelectric transducer) and one or both of the driving frequencies may be adjusted (i.e., detuned) from the fundamental resonant frequency so as to modify one or more parameters of the generated aerosol.
In other examples, the initial first and second driving frequencies may be different frequencies.
By controllably adjusting, or tuning, the first and/or second driving frequency at which the driving signal drives the piezoelectric transducer, one or more properties of the aerosol generated by the aerosol generating apparatus may be controllably adjusted - e.g., according to a user's preference, manufacturer/provider's recommendation, and/or regulatory requirement. Adjusting the driving frequency may be particularly suitable for adjusting an average size of droplets of the aerosol precursor entrained in the generated aerosol and/or a distribution of the size of said droplets.
In examples where one or both of the first and second driving frequencies are adjusted to modify one or more parameters of the generated aerosol, one or more of the initial first driving frequency, new first driving frequency, initial second driving frequency and/or new second driving frequency may be selected based on the one or more parameters of the aerosol precursor and/or the one or more target parameters of the generated aerosol.
In other words, any of the initial and/or new, first and/or second driving frequencies may be controllably selected to provide control (e.g., to a user of the aerosol generating apparatus) over the aerosol generated by the aerosol generating apparatus, taking into account effects that one or more properties of the aerosol precursor may have on the one or more parameters of the generated aerosol.
In some examples, both the first and second driving signals may be direct current signals.
In some examples, the first and second driving signals may share a common, single, polarity.
In some examples, the aerosol generating apparatus further comprises a second tank for storing a second aerosol precursor and a second piezoelectric transducer for generating a second aerosol from the second liquid aerosol precursor. In this case, a second driving signal for driving the second piezoelectric transducer may be generated, wherein the second driving signal is defined by one or more second driving parameters. The generated instructions may include instructions for adjusting the second driving signal to change one or more of the second driving parameters so as to produce a target response of the second piezoelectric transducer to the second driving signal.
As outlined above, the optimal driving parameters, such as the optimal driving frequency (i.e., the resonant frequency) may shift or change over the lifetime of the piezoelectric transducer. For an aerosol generating apparatus comprising more than one piezoelectric transducer, the optimal driving parameters for each piezoelectric transducer may shift or change differently over time, due to variations and tolerances in the manufacturing process. Accordingly, by maintaining an independent set of optimal driving parameters for each of the different piezoelectric transducers of the aerosol generating apparatus, it may be ensured that each piezoelectric transducer is driven as efficiently as possible, thereby improving the efficiency of the aerosol generating apparatus as a whole.
The driving frequencies used for generating the first and second aerosols may be different from each other. In the case where the first liquid aerosol precursor comprises a nicotine formulation and the second liquid aerosol precursor comprises a flavour formulation, the first aerosol may be generated with a higher frequency than the second aerosol, such that the first aerosol has a smaller particle size than the second aerosol. In this way for example, the nicotine containing aerosol may comprise particle sizes suitable for pulmonary penetration, i.e., delivery to the lungs, and the nicotine-free aerosol, i.e., the flavour aerosol, may comprises particle sizes suitable for oral deposition.
In some examples, the generated instructions may be suitable to cause the aerosol-generating apparatus to alternate the activation of only the first piezoelectric transducer and both the first piezoelectric transducer and the second piezoelectric transducer over a series of inhalations of a user of the aerosol generating apparatus.
In other words, the aerosol generating apparatus may be instructed to alternate between generating the first aerosol alone and generating a combination of the first and second aerosols.
Put another way, the aerosol generating apparatus may be instructed to alternate between generating a pure aerosol, i.e., an aerosol comprised of aerosol generated from a single aerosol precursor liquid, such as the first aerosol precursor liquid, and a mixed aerosol, i.e., an aerosol comprises of aerosols generated from multiple different aerosol precursor liquids, such as the first and second aerosol precursor liquids.
In this way, the device may alternate between providing different aerosol compositions to the user over a series of multiple inhalations. By alternating between providing only the first aerosol and both the first and the second aerosol, the user's perception of the aerosol being inhaled, and in particular, the user perception of the second aerosol may be improved.
More specifically, the user perception of the second aerosol may be improved by creating a change in the composition of the aerosol being inhaled between inhalations. For example, if a user takes several inhalations of aerosol containing both the first and the second aerosol, the user may become used to the presence of the second aerosol, and their perception of the second aerosol may decrease. However, by providing an inhalation comprising only the first aerosol, and absent the second aerosol, the subsequent inhalation comprising both the first and the second aerosol will provide the user with a perceived increase in the amount of second aerosol present in the mixture, even if the amount of second aerosol generated either side of the inhalation comprising only the first aerosol remains unchanged.
When referring to perceived changes in the aerosol by the user, it is to be understood that each inhalation comprising both the first aerosol and the second aerosol may be substantially identical, i.e., may comprise the same mixture, or composition, of first and second aerosols. However, when provided in the context of immediately following an inhalation comprising only the first aerosol, the presence of the second aerosol will be more noticeable to the user. Similarly, when provided in the context of an uninterrupted series of inhalations comprising both the first and second aerosols, the presence of the second aerosol will be less noticeable to the user. Therefore, by providing an occasional absence of the second aerosol, the user's perception of the second aerosol will be renewed or refreshed.
In some examples, the first formulation comprises a nicotine formulation. In some examples, the second formulation comprises a flavour formulation. In this way, the device may be adapted to alternate between generating an aerosol containing only nicotine formulation and an aerosol containing a mixture of nicotine formulation and flavour formulation.
As discussed above, in this way the device may be adapted to improve the user perception of the flavour of the second aerosol in the mixed aerosol by providing a change in perceived flavour intensity over a series of inhalations. In this way, the user perception of the flavour may be kept fresh over a longer period of time.
In other words, by providing the user with a change, or modulation, in the flavour profile of the aerosol being inhaled, the user's sensitivity to the flavour may be maintained over a longer period of time. Put another way, modulating the flavour profile of the aerosol being inhaled, by occasionally selectively preventing flavour from being included in an inhalation, the time taken for a user to get used to a flavour may be increased.
In some examples, alternating the activation of only the first piezoelectric transducer and both the first piezoelectric transducer and the second piezoelectric transducer comprises switching from activating both the first piezoelectric transducer and the second piezoelectric transducer to activating only the first aerosol generator and on non-consecutive inhalations of the user of the aerosol generating apparatus.
In this way, the user may be allowed to become used to receiving the mixture of the first and second aerosols over a series of inhalations before the device alternates between generating only the first aerosol and generating both the first and the second aerosol. Thus, the user may be provided with a greater perceived change, or refresh, in the intensity of the second aerosol, e.g., the flavour.
In some examples, alternating the activation of only the first piezoelectric transducer and both the first piezoelectric transducer and the second piezoelectric transducer comprises: activating both the first piezoelectric transducer and the second piezoelectric transducer for one or more inhalations of the user of the aerosol generating apparatus before switching to activating only the first piezoelectric transducer; and activating only the first piezoelectric transducer for a single inhalation of the user of the aerosol generating apparatus before switching to activating both the first piezoelectric transducer and the second piezoelectric transducer.
In this way, the device may be limited to generating an aerosol with only the first aerosol precursor for only a single inhalation before switching to generating an aerosol with both the first and second aerosol precursor. In this way, the number of inhalations without the second aerosol present may be minimized whilst still providing the user with a perceived change, or refresh, in intensity of the second aerosol, e.g., the flavour.
In some examples, alternating the activation of only the first piezoelectric transducer and both the first piezoelectric transducer and the second piezoelectric transducer comprises switching between activating only the first piezoelectric transducer and activating both the first piezoelectric transducer and the second piezoelectric transducer on consecutive inhalations of the user of the aerosol generating aparatus.
In this way, the device may alternate between generating only the first aerosol and generating both the first and the second aerosol with each inhalation of the user. Thus, the user may be provided with a perceived change, or refresh, in intensity of the second aerosol, e.g., the flavour, with every other inhalation.
In some examples, the received data may include an elapsed time since an inhalation last occurred; and the generated instructions may include a conditional instruction to switch to activating both the first piezoelectric transducer and the second piezoelectric transducer for a next inhalation of the user of the aerosol generating apparatus based on the elapsed time.
In this way, the device may be adapted to reset the alternation between activating only the first piezoelectric transducer and activating both the first piezoelectric transducer and the second piezoelectric transducer after a given period of inactivity, i.e., the elapsed time since an inhalation last occurred.
The user's perception of the second aerosol will be naturally refreshed after a period of time following an inhalation. Thus, by switching to activating both the first piezoelectric transducer and the second piezoelectric transducer after a given period of inactivity, the user will be provided with a perceived change in intensity of the second aerosol, e.g., the flavour, naturally. Further, in this way, the device may be prevented from generating only the first aerosol in response to the first inhalation of a user in an inhalation session, thereby preventing the first inhalation of an inhalation session from lacking the second aerosol, which may for example be the flavour.
In some examples, the conditional instruction to switch to activating both the first piezoelectric transducer and the second piezoelectric transducer based on the elapsed time comprises instructions to: determine whether the elapsed time exceeds a predetermined period; if the elapsed time exceeds the predetermined period, switch to activating both the first piezoelectric transducer and the second piezoelectric transducer; and if the elapsed time exceeds the predetermined period, maintain a current activation state of the first and second piezoelectric transducer.
In this way, the device may recognise a new inhalation session, and respond by activating both the first piezoelectric transducer and the second piezoelectric transducer as the user perception of the second aerosol will already be naturally refreshed by virtue of the elapsed time since an inhalation last occurred being sufficiently long.
In some examples, the aerosol generating apparatus further comprises a pressure sensor adapted to sense an inhalation of the user. In some such examples, the received data may include an inhalation signal generated in response to sensing the inhalation of the user, and the generated instructions may include a conditional instruction to activate only the first piezoelectric transducer, or both the first piezoelectric transducer and the second piezoelectric transducer, in response to the inhalation signal. In this way, the device may respond automatically to an inhalation of the user based on the pressure sensor, rather than requiring an additional user input.
In some examples, the generated instructions may include an instruction to adjust a function of the aerosol-generating apparatus. Adjusting a function of the aerosol generating apparatus comprises adjusting a number of inhalations for which both the first piezoelectric transducer and the second piezoelectric transducer are activated before switching to activating only the piezoelectric transducer. In this way, the device may be adapted to alternate between activating only the first piezoelectric transducer or activating both the first piezoelectric transducer and the second piezoelectric transducer according to a user preference.
In some examples, adjusting a function of the aerosol generating apparatus comprises adjusting the predetermined period. In this way, the device may be adapted to alternate between activating only the first piezoelectric transducer or activating both the first piezoelectric transducer and the second piezoelectric transducer according to a user preference.
In some examples, the generated instructions may include one or more instructions for delaying the activation of the first piezoelectric transducer relative to the activation of the second piezoelectric transducer for a first delay period, or vice versa. The instruction may be a conditional instruction such that the delay is triggered in response to an inhalation of a user of the aerosol generating apparatus.
In other words, the aerosol generating apparatus may be adapted to produce the second aerosol for a short period before the first aerosol is produced, during a given inhalation.
Put another way, the aerosol generating apparatus may be adapted to deliver the second aerosol ahead of the first aerosol.
In this way, the device may improve the user perception of the aerosol inhaled by masking one aerosol with another aerosol. In particular, the first aerosol, for example the taste of the first aerosol, may be masked, blocked or covered using the second aerosol by starting to provide the second aerosol to the user before the first aerosol. After the delay period, the first and second aerosols may be delivered to the user simultaneously for the remainder of the inhalation.
In some examples, the first formulation comprises a nicotine formulation. In some examples, the second formulation comprises a flavour formulation. In this way, the device may be adapted to delay generating the first aerosol containing only nicotine formulation for a first delay period, during which the device is generating the second aerosol, which contains the flavour formulation.
Put another way, the device may be adapted to provide the user with a flavoured aerosol ahead of an aerosol containing only nicotine formulation. As discussed above, in this way the device may be adapted to mask the taste of the nicotine formulation by delaying the generation of the first aerosol with respect to the generation of the second aerosol. In this way, the user perception of the combined aerosol, comprising the first and second aerosols, may be improved.
In some examples, prior to generating the instruction encoding the delay between the activations of the first and second piezoelectric transducers, the method may comprise determining an optimal first delay period based on the received data, which may include data indicative of an average inhalation duration of the user.
In this way, the device may adapt to the user's typical inhalation period over time in order to determine an optimal first delay period such that the first aerosol is masked by the second aerosol, but a sufficient amount of first aerosol is also delivered within the user's typical inhalation period. For example, for a user with a shorter average inhalation period, the first delay period may be reduced, and for a user with a longer average inhalation period, the first delay period may be extended.
In some examples, the generated instructions may include instructions that select which of the first and second piezoelectric transducer's activations is delayed with respect to the other. For example, by providing the first aerosol ahead of the second aerosol, the user may be provided with a perceived change in the intensity of the second aerosol, thereby improving the user's perception of the second aerosol.
More specifically, the user perception of the second aerosol may be improved by creating a change in the composition of the aerosol being inhaled between inhalations. For example, if a user takes several inhalations of aerosol with the second aerosol generated before the first aerosol, the user may become used to the presence of the second aerosol, and their perception of the second aerosol may decrease. However, by providing an inhalation where the first aerosol is generated ahead of the second aerosol, the subsequent inhalation where the second aerosol is provided before the first aerosol will provide the user with a perceived increase in the amount of second aerosol present in the mixture.
When provided in the context of immediately following an inhalation where the first aerosol is generated ahead of the second aerosol, in an inhalation where the second aerosol is generated ahead of the first aerosol the presence of the second aerosol will be more noticeable to the user. Similarly, when provided in the context of an uninterrupted series of inhalations where the second aerosol is generated before the first aerosol, the presence of the second aerosol may become less noticeable to the user. Therefore, by providing an occasional inhalation where the first aerosol is generated before the second aerosol, i.e., the generation of the second aerosol is delayed with respect to the first aerosol, the user's perception of the second aerosol will be renewed or refreshed.
In some examples, alternating between the delaying of the activation of the first piezoelectric transducer with respect to the activation of the second piezoelectric transducer and delaying the activation of the second piezoelectric transducer with respect to the activation of the first piezoelectric transducer may be performed on non-consecutive inhalations of the user of the aerosol generating apparatus. In this way, the user may be allowed to become used to receiving the second aerosol ahead of the first aerosol before the device switches to delaying the second aerosol with respect to the first aerosol. Thus, the user may be provided with a greater perceived change, or refresh, in intensity of the second aerosol, e.g., the flavour.
In some examples, the generated instructions may include one or more instructions for modulating the activation of the first piezoelectric transducer and the second piezoelectric transducer over a single inhalation period in response to an inhalation of a user of the aerosol generating apparatus.
In other words, as the user inhales, the aerosol generating apparatus is instructed to modulate the activation of the first and second aerosol generators over the course of the inhalation.
Put another way, the aerosol generating apparatus may be adapted to modulate the generation and delivery of the first and second aerosols over the course of an inhalation.
Modulation of the generation of the first and second aerosols may improve the user perception of the first aerosol and/or the second aerosol on a per inhalation basis as described in further detail in the examples provided below.
Modulating the activation of the first aerosol generator and the second aerosol generator over the single inhalation period may comprise one or more of: alternating an activation state of the first and second aerosol generators over the single inhalation period.
In some examples, modulating the activation of the first aerosol generator and the second aerosol generator over the single inhalation period further comprises delaying the activation state of one of the first and second aerosol generators with respect to another of the first and second aerosol generators over the single inhalation period.
In some examples, the generated instructions include one or more instructions for alternating the activation of the first aerosol generator and the second aerosol generator over a series of inhalations of a user of the aerosol generating apparatus, wherein alternating the activation of the first aerosol generator and the second aerosol generator comprises switching between activating the first/second aerosol generator and activating the second/first aerosol generator on consecutive inhalations.
In other words, the aerosol generating apparatus may be instructed to alternate between generating the first aerosol alone and generating the second aerosol alone or alternate between generating the second aerosol alone and generating the first aerosol alone.
Put another way, the aerosol generating apparatus may be instructed to alternate between generating different pure aerosols, i.e., aerosols generated from a single aerosol precursor.
In this way, the device may alternate between providing different aerosols to the user over a series of multiple inhalations. By alternating between providing only the first aerosol and only the second aerosol, the user's perception of the respective aerosol being inhaled, i.e., the user perception of the first aerosol and the second aerosol, in turn, may be improved.
In some examples, the generated instructions include one or more instructions for adjusting a ratio of an amount of first aerosol generated in response to an inhalation to an amount of second aerosol generated in response to an inhalation based on the strength of the inhalation. Such an instruction may, for example, be a conditional instruction.
In other words, there is provided a means of controlling the concentration of the first aerosol within the combined aerosol, comprising both the first and the second aerosols, provided to the user.
Put another way, there is provided a means of adjusting the dilution of a first aerosol by a second aerosol within a total combined aerosol that is inhaled by the user.
By controlling the ratio of the amount of first aerosol generated to the amount of second aerosol generated based on the strength of the inhalation, the consistency in the amount of a given formulation, such as the first formulation, delivered to the user may be improved.
For example, when a strong inhalation is detected, the concentration of the first aerosol in the delivered mixture of aerosol may be decreased in order to prevent over-delivery of the first aerosol precursor to the user. The concentration of the first aerosol in the delivered mixture of aerosol may be decreased by controlling the aerosol generation unit to generate less first aerosol and/or more second aerosol to make up the mixture of aerosols delivered to the user.
In a further example, when a weak inhalation is detected, the concentration of the first aerosol in the delivered mixture may be increased in order to prevent under-delivery of the first aerosol precursor, for example, in order to achieve a satisfactory level of first aerosol delivery to the user. The concentration of the first aerosol in the delivered mixture of aerosol may be increased by controlling the aerosol generation unit to generate more first aerosol and/or less second aerosol to make up the mixture of aerosols delivered to the user.
The step of determining the strength of the inhalation may be performed during an initial period of an inhalation. The initial period of the inhalation may be less than the total inhalation period, i.e., may be less than the total duration of the inhalation.
In some examples, the first liquid aerosol precursor is a nicotine formulation. In some examples, the second liquid aerosol precursor is: a flavour formulation; or a plain formulation. In this way, the device may actively adjust the concentration of nicotine in the delivered mixture of aerosols based on the inhalation strength of the user.
In this way, the relative strength of an inhalation may be determined in order to adjust the ratio of the first aerosol generated to the second aerosol generated. In particular, the measured inhalation strength may be compared to a threshold value, i.e., an upper inhalation strength threshold, and, if the measured inhalation strength meets or exceeds the upper inhalation strength threshold, the device may determine that the inhalation is relatively strong. When an inhalation is determined to be a strong inhalation, the concentration of the first aerosol in the delivered mixture of aerosol may be decreased in order to prevent over-delivery of the first aerosol, which may comprise a nicotine formulation, to the user.
The upper inhalation strength threshold may be a predetermined threshold set at a predetermined pressure value. Alternatively, the upper inhalation strength threshold may be set to a predetermined deviation from a baseline pressure, for example a percentage increase in pressure. The upper inhalation strength threshold may be adjusted over time based on an average inhalation strength of the user.
In some examples, adjusting the ratio of the amount of first aerosol to the amount of second aerosol generated in response to the inhalation comprises: comparing the strength of the inhalation to a lower inhalation strength threshold; and if the strength of the inhalation is less than or equal to the lower inhalation strength threshold, increasing the ratio of the first aerosol generate to the second aerosol generated.
In this way, the relative strength of an inhalation may be determined in order to adjust the ratio of the first aerosol generated to the second aerosol generated. In particular, the measured inhalation strength may be compared to a threshold value, i.e., the lower inhalation strength threshold, and, if the measured inhalation strength meets or falls below the lower inhalation strength threshold, the device may determine that the inhalation is relatively weak. When an inhalation is determined to be a weak inhalation, the concentration of the first aerosol in the delivered mixture of aerosol may be increased in order to prevent under-delivery of the first aerosol, which may comprise a nicotine formulation, to the user.
The lower inhalation strength threshold may be a predetermined threshold set at a predetermined pressure value. Alternatively, the lower inhalation strength threshold may be set to a predetermined deviation from a baseline pressure, for example a percentage increase in pressure. The lower inhalation strength threshold may be adjusted over time based on an average inhalation strength of the user.
The upper inhalation strength threshold and the lower inhalation strength threshold may form a range within which an average inhalation strength lies. Any inhalation of the user will cause an increase in the measured pressured compared to a baseline pressure measured by the inhalation sensor when no inhalation is occurring. In response to an average strength inhalation, the increase in pressure from the baseline pressure will result in a measured inhalation strength that lies between the upper inhalation strength threshold and the lower inhalation strength threshold. In response to a strong inhalation, the increase in pressure from the baseline pressure will result in a measured inhalation strength that lies at or above the upper inhalation strength threshold. In response to a weak inhalation, the increase in pressure from the baseline pressure will result in a measured inhalation strength that lies at or below the lower inhalation strength threshold.
The measured inhalation strength may be a relative pressure measurement, i.e., a change in sensed pressure from a baseline, such as atmospheric pressure, in response to a user inhalation. Alternatively, the measured inhalation strength may be an absolute pressure measurement.
Adjusting the ratio of the first aerosol generated to the second aerosol generated may be performed by adjusting any one of the driving parameters in the first and second sets of driving parameters of the driving circuits used to drive the first and second piezoelectric transducers, thereby providing multiple different means of adjusting the behaviour of the first and/or second piezoelectric transducer in order to adjust the ratio of the first aerosol generated to the second aerosol generated.
In some examples, decreasing the ratio of the first aerosol generated to the second aerosol generated comprises one or more of: decreasing the first driving duty cycle; decreasing the first driving power; increasing the second driving duty cycle; and increasing the second driving power.
Put another way, decreasing the ratio of the first aerosol generated to the second aerosol generated may be performed by: adjusting one or more of the first set of driving parameters for driving the first piezoelectric transducer to decrease the amount of first aerosol generated; adjusting one or more of the second set of driving parameters for driving the second piezoelectric transducer to increase the amount of second aerosol generated; or a combination of both.
In some examples, increasing the ratio of the first aerosol generated to the second aerosol generated comprises one or more of: increasing the first driving duty cycle; increasing the first driving power; decreasing the second driving duty cycle; and decreasing the second driving power.
Put another way, increasing the ratio of the first aerosol generated to the second aerosol generated may be performed by: adjusting one or more of the first set of driving parameters for driving the first piezoelectric transducer to increase the amount of first aerosol generated; adjusting one or more of the second set of driving parameters for driving the second piezoelectric transducer to decrease the amount of second aerosol generated; or a combination of both.
For example, when a strong inhalation is detected, the first driving power may be decreased in order to decrease the concentration of the first aerosol in the delivered mixture of aerosol in order to prevent over-delivery of the nicotine formulation to the user. Alternatively, or in addition, when a strong inhalation is detected, the second driving power may be increased in order to decrease the concentration of the first aerosol in the delivered mixture of aerosol whilst maintaining a consistent amount of aerosol mixture delivered to the user.
In a further example, when a weak inhalation is detected, the first driving power may be increased in order to increase the concentration of the first aerosol in the delivered mixture of aerosol in order to prevent under-delivery of the nicotine formulation to the user. Alternatively, or in addition, when a weak inhalation is detected, the second driving power may be decreased in order to increase the concentration of the first aerosol in the delivered mixture of aerosol whilst maintaining a consistent amount of aerosol mixture delivered to the user.
In another example, when a strong inhalation is detected, the first driving duty cycle may be decreased in order to decrease the concentration of the first aerosol in the delivered mixture of aerosol in order to prevent over-delivery of the nicotine formulation to the user. Alternatively, or in addition, when a strong inhalation is detected, the second driving duty cycle may be increased in order to decrease the concentration of the first aerosol in the delivered mixture of aerosol whilst maintaining a consistent amount of aerosol mixture delivered to the user.
In a further example, when a weak inhalation is detected, the first driving duty cycle may be increased in order to increase the concentration of the first aerosol in the delivered mixture of aerosol in order to prevent under-delivery of the nicotine formulation to the user. Alternatively, or in addition, when a weak inhalation is detected, the second driving duty cycle may be decreased in order to increase the concentration of the first aerosol in the delivered mixture of aerosol whilst maintaining a consistent amount of aerosol mixture delivered to the user.
In some examples, the aerosol-generating apparatus includes a charging port arranged to receive power from an external power source so as to charge the power supply. The first driving circuit (i.e., the driving circuit arranged to drive the first piezoelectric transducer) is configured, in a driving configuration, to drive the first piezoelectric transducer to generate the first aerosol. The second driving circuit (i.e., the driving circuit arranged to drive the second piezoelectric transducer) is configured, in a driving configuration, to drive the second piezoelectric transducer to generate the second aerosol. The first and/or second driving circuits are controllably switchable, upon execution of correspondingly generated instructions, to switch to a charging configuration. When the first or second driving circuit is in the charging configuration, said driving circuit is configured to transfer power from the charging port to the power supply to charge the power supply.
In some examples, the generated instructions may include an instruction to switch one of the first and second driving circuits to the charging configuration (e.g., from the driving configuration) in response to a determination that an external power source is connected to the charging port.
Operation of the aerosol generating apparatuses described herein may be maintained whilst the apparatus is charged without requiring the mechanical and electrical burden of need a bespoke charging circuit. In other words, the aerosol generating apparatuses as described herein may be beneficial because they do not require the costly/complex addition of bespoke charging circuitry which may be difficult to achieve within the dimensional constraints of the aerosol generating apparatus. Specifically, it allows for an aerosol generating apparatus to be provided that can simultaneously be operated and charged without requiring an unnecessarily large/bulky apparatus to accommodate the required circuitry.
The first driving circuit may be arranged to electrically (and switchably) connect the power supply to the first piezoelectric transducer, the power supply to the charging port, and the first piezoelectric transducer to the charging port.
Similarly, the second driving circuit may be arranged to electrically (and switchably) connect the power supply to the second piezoelectric transducer, the power supply to the charging port, and the second piezoelectric transducer to the charging port.
In some examples, the first and/or second driving circuits may be further controllably switchable, upon execution of correspondingly generated instructions, to switch to an on-charge driving configuration. The switch to the on-charge driving configuration may be in response to a determination that the charging port is receiving power from an external power source such that, in response to said determination, one of the first and second driving circuits may be switched to the charging configuration, and the other of the first and second driving circuits may be switched to the on-charge driving configuration. When the first or second driving circuit is in the on-charge driving configuration, said driving circuit may be configured to transfer power from the charging port to the corresponding piezoelectric transducer so as to generate a corresponding aerosol.
In this way, power for operating the aerosol generating apparatus may be drawn from the external power source such that there is no attempt to drain the power supply of the aerosol generating apparatus while it is being charged.
For example, an aerosol generating apparatus may be used with both the first and second driving circuits in the driving configuration to generate first and second aerosols using the first and second aerosol generation units respectively. In response to an external power source being connected to the charging port of the aerosol generating apparatus, the first driving circuit may be switched from the driving configuration to the charging configuration, and the second driving circuit may (simultaneously or consequently) be switched from the driving configuration to the on-charge driving configuration such that the aerosol generating apparatus is still operable to generate the second aerosol while the power supply is charged. Conversely, in response to an external power source being connected to the charging port of the aerosol generating apparatus, the second driving circuit may be switched from the driving configuration to the charging configuration, and the first driving circuit may (simultaneously or consequently) be switched from the driving configuration to the on-charge driving configuration such that the aerosol-generating apparatus is still operable to generate the first aerosol while the power supply is charged.
The first and/or second driving circuits may, in some examples, be switchable, upon execution of the appropriate instruction, between any of the driving configuration, charging configuration and on-charge driving configuration.
The first piezoelectric transducer may be controllably driven at the first driving frequency through actuation of a first switch of the first driving circuit. The second piezoelectric transducer may be controllably driven at the second driving frequency through actuation of a second switch of the second driving circuit.
In some examples, the first and second driving frequencies may be a common driving frequency. In such examples, it may be possible to embody the first and second switch as a single switch to actuate the delivery of current through the first and second driving circuits synchronously.
In some examples, the first switch may be a MOSFET switch. Additionally or alternatively, in some examples, the second switch may be a MOSFET switch. In some examples, the first and second switches may be driven by a common MOSFET power source. Alternatively, in some examples, the first and second switches may be driven by respectively different MOSFET power sources.
To drive the first and/or second piezoelectric transducer at such high frequencies, requires a similarly fast actuation of the first and/or second switches. Such rapid actuation of switches may be readily achievable using MOSFET switches.
In some examples, the first switch may be connected to a first oscillator or first clock for actuating the first switch at the first driving frequency. Additionally or alternatively, in some examples, the second switch may be connected to a second oscillator or second clock for actuating the second switch at the second driving frequency. In some examples, the first and second oscillator/clock may be a common oscillator/clock. Alternatively, in some examples, the first and second oscillator/clock may be respectively different oscillators/clocks. For example, the first switch may be connected to an oscillator and the second switch may be connected to a clock, or vice versa; or the first and second switch may be respectively connected to first and second oscillators, or to first and second clocks.
In some examples, the power supply may be a rechargeable battery.
In some examples, the received data may include data indicative of whether the charging port is receiving power from an external power source. In some examples, the generated instructions may include a condition instruction to cause said driving circuit to switch from the driving configuration to the charging configuration in response to a determination that the charging port is receiving power from an external power source.
In this way, one of the first and second driving circuits may continue in the driving configuration such that simultaneous operation and charging of the aerosol generating apparatus is achieved.
In some examples, the received user input may be indicative of a user selection of which of the first and second driving circuits to switch to the charging configuration; and transmitting the switching signal to the selected driving circuit.
In this way, the user may choose which of the first and second aerosols they wish to continue receiving during user of the aerosol generating apparatus, while the apparatus is on-charge. For example, in cases where the first aerosol includes a nicotine-containing component and the second aerosol includes a flavouring, the user can select which of flavour and nicotine they wish to inhale during an on-charge operation of the aerosol generating apparatus.
In some examples, the user may be able to provide input to change which of the first and second driving circuits is in an on-charge configuration, and which is in a driving (e.g., in an on-charge driving) configuration such that the user is not constrained to only receive the first aerosol or only receive the second aerosol while the device is on charge, but rather is able to switch between the first and second aerosol as desired or needed.
In some examples, the user input may be received e.g., via a user interaction with an application on their personal device (e.g., a mobile phone).
In some examples, the user input may include one or more preset (or default) user preferences that the method may implement as standard, unless the user provides specific input to override the preset (default) preferences.
In some examples the manufacturer and/or provided of the aerosol generating apparatus may provide the device with a "factory" default such that user input is not necessarily required. In other words, the factory default may provide a default selection that can be overridden, either by a specific user input or by the user providing the one or more preset (default) user preferences.
In another aspect, the present disclosure provides electrical circuitry for an aerosol generating system, the electrical circuitry being arranged to perform any of the methods described herein.
In embodiments, the electrical circuitry is implemented as one or more processors, which are configured to implement the disclosed steps, e.g. as the controller. The processors may execute program code stored on electronic memory and/or may execute logic, e.g. as a logic array, gate array, structured gate array.
As will be apparent from the present disclosure, the methods described herein may be carried out, or implemented, by a computer. The computer may, for example, be a processor installed in the aerosol generating apparatus and configured to operate as a control unit of the aerosol generating apparatus. Alternatively, the computer may, for example, be a remote computer communicatively connectable to the aerosol generating apparatus via a communications interface of the aerosol generating apparatus. Alternatively, the computer may be embodied as a distributed computing environment, including for example, both a control unit installed in the aerosol generating apparatus and a remote computer that is communicatively connectable to the control unit via a communications interface of the aerosol generating apparatus.
Moreover, the acts described herein may be embodied using computer-executable instructions that can be implemented by one or more processors and/or stored on a computer-readable medium or media. The computer-executable instructions can include routines, sub-routines; programs; threads of execution, and/or the like. Still further, results of acts of the methods can be stored in a computer-readable medium, displayed on a display device, and/or the like.
The order of the operations of the methods described herein is exemplary, but the steps may be carried out in any suitable order, or simultaneously where appropriate. Additionally, steps may be added or substituted in, or individual steps may be deleted from any of the methods without departing from the scope of the subject matter described herein. Aspects of any of the examples described above may be combined with aspects of any of the other examples described to form further examples without losing the effect sought.
Various functions described herein can be implemented in hardware, software, or any combination thereof. If implemented in software, the functions can be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media may include, for example, computer-readable storage media. Computer-readable storage media may include volatile or non-volatile, removable or non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. A computer-readable storage media can be any available storage media that may be accessed by a computer. By way of example, and not limitation, such computer-readable storage media may comprise RAM, ROM, EEPROM, flash memory or other memory devices, CD-ROM or other optical disc storage, magnetic disc storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer.
Although illustrated as a local device it will be appreciated that the computing device may be located remotely and accessed via a network or other communication link (for example using a communication interface).
The term 'computer' is used herein to refer to any device with processing capability such that it can execute instructions. Those skilled in the art will realise that such processing capabilities are incorporated into many different devices and therefore the term 'computer' includes PCs, servers, mobile telephones, personal digital assistants and many other devices.
Those skilled in the art will realise that storage devices utilised to store program instructions can be distributed across a network. For example, a remote computer may store an example of the process described as software. A local or terminal computer may access the remote computer and download a part or all of the software to run the program. Alternatively, the local computer may download pieces of the software as needed or execute some software instructions at the local terminal and some at the remote computer (or computer network). Those skilled in the art will also realise that by utilising conventional techniques known to those skilled in the art that all, or a portion of the software instructions may be carried out by a dedicated circuit, such as a DSP, programmable logic array, or the like.
It will be understood that the benefits and advantages described above may relate to one embodiment or may relate to several embodiments. The embodiments are not limited to those that solve any or all the stated problems or those that have any or all of the stated benefits and advantages. Variants should be considered to be included into the scope of the invention.
The present disclosure may provide electrical circuitry and/or a computer program configured to cause an aerosol generating apparatus/system to perform any method or method step disclosed herein. A computer readable medium comprising the computer program is also disclosed.
The preceding summary is provided for purposes of summarizing some examples to provide a basic understanding of aspects of the subject matter described herein. Accordingly, the above-described features should not be construed to narrow the scope or spirit of the subject matter described herein in any way. Moreover, the above and/or proceeding examples may be combined in any suitable combination to provide further examples, except where such a combination is clearly impermissible or expressly avoided. Other features, aspects, and advantages of the subject matter described herein will become apparent from the following text and the accompanying drawings.

BRIEF DESCRIPTION OF THE FIGURES

Aspects, features and advantages of the present disclosure will become apparent from the following description of examples in reference to the appended drawings in which like numerals denote like elements.

Fig. 1 is a block system diagram showing an example aerosol generating apparatus.
Fig. 2 is a block system diagram showing an example implementation of the apparatus of Fig. 1, where the aerosol generating apparatus is configured to generate aerosol from a liquid precursor.
Figs. 3A and 3B are schematic diagrams showing an example implementation of the apparatus of Fig. 2.
Fig. 4 is a block system diagram showing an example system for managing an aerosol generating apparatus.
Fig. 5 shows an example of a circuit for modelling the behaviour of an exemplary piezoelectric transducer.
Fig. 6 shows a portion of an exemplary driving circuit using an H-bridge.
Fig. 7 shows an example of an improved driving circuit for driving a piezoelectric transducer.
Fig. 8 is a block system diagram showing an example aerosol generating apparatus having first and second aerosol generation units.
Fig. 9 shows an example of first and second driving circuits for driving respective piezoelectric transducers.
Figs. 10a to 10c show exemplary configurations of three-way switches suitable for switching the driving circuits of Fig. 9 between charging, driving, and on-charge driving configurations.
Fig. 11 shows a schematic representation of an aerosol generating apparatus according to an aspect of the invention.
Fig. 12 shows a schematic representation of an aerosol generating apparatus according to an aspect of the invention.
Fig. 13 shows an example of an aerosol generating apparatus.
Fig. 14 shows an exemplary frequency response in the current flowing through a piezoelectric transducer.
Fig. 15 shows two exemplary frequency responses in the current flowing through a piezoelectric transducer.
Figs. 16a-16c shows an exemplary voltage response to a driving signal having a duty cycle of 50%, 40% and 25% respectively.
Fig. 17 shows a method for controlling an aerosol generating apparatus.
Fig. 18 shows a method for identifying a resonant frequency of a piezoelectric transducer.
Fig. 19 shows a method of determining instructions for encoding in a control signal of the method of
Fig. 17.
Fig. 20 shows another method for controlling an aerosol generating apparatus.
Fig. 21 shows an exemplary method of controlling an aerosol generating apparatus.
Fig. 22 shows a method of controlling an aerosol generating apparatus.
Fig. 23 shows a method of controlling an aerosol generating apparatus.
Fig. 24 shows a method for controlling an aerosol generating apparatus.
Fig. 25 shows a schematic representation of the driving scheme for two aerosol generating units according to the method shown in Fig. 24.
Fig. 26 shows a method for controlling an aerosol generating apparatus.
Fig. 27 shows a schematic representation of the driving scheme for two aerosol generating units according to the method shown in Fig. 26.
Fig. 28 shows a method for controlling an aerosol generating apparatus.
Fig. 29 shows a schematic representation of the driving scheme for two aerosol generating units according to the method shown in Fig. 28.
Fig. 30 shows a method for controlling an aerosol generating apparatus according to an aspect of the invention.
Fig. 31 shows a schematic representation of the driving scheme for two aerosol generating units according to the method shown in Fig. 30.
Fig. 32 shows a method for controlling the aerosol generating apparatus shown in Fig. 11.
Fig. 33 shows a further method for controlling the aerosol generating apparatus shown in Fig. 11.
Fig. 34 shows a schematic representation of the methods shown in Figs. 32 and 33.
Fig. 35 shows a method for driving a piezoelectric transducer of an aerosol generating apparatus according to an aspect of the invention.
Fig. 36 shows a method for driving a piezoelectric transducer of an aerosol generating apparatus according to an aspect of the invention.
Fig. 37 shows an example of a method for controlling the aerosol generating apparatus of Fig. 13.
Fig. 38 shows an example of a method for controlling the aerosol generating apparatus of Fig. 13.
Fig. 39 shows a further example of a method for controlling the aerosol generating apparatus of Fig. 13.

DETAILED DESCRIPTION OF EMBODIMENTS

Before describing several examples implementing the present disclosure, it is to be understood that the present disclosure is not limited by specific construction details or process steps set forth in the following description and accompanying drawings. Rather, it will be apparent to those skilled in the art having the benefit of the present disclosure that the systems, apparatuses and/or methods described herein could be embodied differently and/or be practiced or carried out in various alternative ways.
Unless otherwise defined herein, scientific and technical terms used in connection with the presently disclosed inventive concept(s) shall have the meanings that are commonly understood by those of ordinary skill in the art, and known techniques and procedures may be performed according to conventional methods well known in the art and as described in various general and more specific references that may be cited and discussed in the present specification.
Any patents, published patent applications, and non-patent publications mentioned in the specification are hereby incorporated by reference in their entirety.
All examples implementing the present disclosure can be made and executed without undue experimentation in light of the present disclosure. While particular examples have been described, it will be apparent to those of skill in the art that variations may be applied to the systems, apparatus, and/or methods and in the steps or in the sequence of steps of the methods described herein without departing from the concept, spirit, and scope of the inventive concept(s). All such similar substitutions and modifications apparent to those skilled in the art are deemed to be within the spirit, scope, and concept of the inventive concept(s) as defined by the appended claims.
The use of the term "a" or "an" in the claims and/or the specification may mean "one," as well as "one or more," "at least one," and "one or more than one." As such, the terms "a," "an," and "the," as well as all singular terms, include plural referents unless the context clearly indicates otherwise. Likewise, plural terms shall include the singular unless otherwise required by context.
The use of the term "or" in the present disclosure (including the claims) is used to mean an inclusive "and/or" unless explicitly indicated to refer to alternatives only or unless the alternatives are mutually exclusive. For example, a condition "A or B" is satisfied by any of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).
As used in this specification and claim(s), the words "comprising, "having," "including," or "containing" (and any forms thereof, such as "comprise" and "comprises," "have" and "has," "includes" and "include," or "contains" and "contain," respectively) are inclusive or open-ended and do not exclude additional, unrecited elements or method steps.
Unless otherwise explicitly stated as incompatible, or the physics or otherwise of the embodiments, examples, or claims prevent such a combination, the features of examples disclosed herein, and of the claims, may be integrated together in any suitable arrangement, especially ones where there is a beneficial effect in doing so. This is not limited to only any specified benefit, and instead may arise from an "ex post facto" benefit. This is to say that the combination of features is not limited by the described forms, particularly the form (e.g. numbering) of example(s), embodiment(s), or dependency of claim(s). Moreover, this also applies to the phrase "in one embodiment," "according to an embodiment," and the like, which are merely a stylistic form of wording and are not to be construed as limiting the following features to a separate embodiment to all other instances of the same or similar wording. This is to say, a reference to 'an,' 'one,' or 'some' embodiment(s) may be a reference to any one or more, and/or all embodiments, or combination(s) thereof, disclosed. Also, similarly, the reference to "the" embodiment may not be limited to the immediately preceding embodiment. Further, all references to one or more embodiments or examples are to be construed as non-limiting to the claims.
The present disclosure may be better understood in view of the following explanations, wherein the terms used that are separated by "or" may be used interchangeably:
As used herein, an "aerosol generating apparatus" (or "electronic(e)-cigarette") may be an apparatus configured to deliver an aerosol to a user for inhalation by the user. The apparatus may additionally/alternatively be referred to as a "smoking substitute apparatus", if it is intended to be used instead of a conventional combustible smoking article. As used herein a combustible "smoking article" may refer to a cigarette, cigar, pipe or other article, that produces smoke (an aerosol comprising solid particulates and gas) via heating above the thermal decomposition temperature (typically by combustion and/or pyrolysis). An aerosol generated by the apparatus may comprise an aerosol with particle sizes of 0.2 - 7 microns, 2-3 microns, or less than 10 microns, or less than 7 microns, or less than 3 microns, or less than 2 microns. This particle size may be achieved by control of one or more of: driving parameters of the ultrasonic generator; flow properties including turbulence and velocity. The generation of aerosol by the aerosol generating apparatus may be controlled by an input device. The input device may be configured to be user-activated, and may for example include or take the form of an actuator (e.g. actuation button) and/or an airflow sensor.
Each occurrence of the aerosol generating apparatus being caused to generate aerosol for a period of time (which may be variable) may be referred to as an "activation" of the aerosol generating apparatus. The aerosol generating apparatus may be arranged to allow an amount of aerosol delivered to a user to be varied per activation (as opposed to delivering a fixed dose of aerosol), e.g. by activating an aerosol generating unit of the apparatus for a variable amount of time, e.g. based on the strength/duration of a draw of a user through a flow path of the apparatus (to replicate an effect of smoking a conventional combustible smoking article).
The aerosol generating apparatus may be portable. As used herein, the term "portable" may refer to the apparatus being for use when held by a user.
As used herein, an "aerosol generating system" may be a system that includes an aerosol generating apparatus and optionally other circuitry/components associated with the function of the apparatus, e.g. one or more external devices and/or one or more external components (here "external" is intended to mean external to the aerosol generating apparatus). As used herein, an "external device" and "external component" may include one or more of a: a charging device, a mobile device (which may be connected to the aerosol generating apparatus, e.g. via a wireless or wired connection); a networked-based computer (e.g. a remote server); a cloud-based computer; any other server system.
An example aerosol generating system may be a system for managing an aerosol generating apparatus. Such a system may include, for example, a mobile device, a network server, as well as the aerosol generating apparatus.
As used herein, an "aerosol" may include a suspension of liquid droplets of precursor. An aerosol may include one or more components of the precursor.
As used herein, a "precursor" may include one or more of a: liquid; gel. The precursor may be processed by an aerosol generating unit of an aerosol generating apparatus to generate an aerosol. The precursor may include one or more of: an active component; a carrier; a flavouring. The active component may include one or more of nicotine; caffeine; a cannabidiol oil; a non-pharmaceutical formulation, e.g. a formulation which is not for treatment of a disease or physiological malfunction of the human body. The active component may be carried by the carrier, which may be a liquid, including propylene glycol and/or glycerine. The term "flavouring" may refer to a component that provides a taste and/or a smell to the user. The flavouring may include one or more of: Ethylvanillin (vanilla); menthol, Isoamyl acetate (banana oil); or other. The precursor may include a carrier; a flavouring.
As used herein, a "storage portion" may be a portion of the apparatus adapted to store the precursor. It may be implemented as fluid-holding reservoir depending on the implementation of the precursor as defined above.
As used herein, a "flow path" may refer to a path or enclosed passageway through an aerosol generating apparatus, e.g. for delivery of an aerosol to a user. The flow path may be arranged to receive aerosol from an aerosol generating unit. When referring to the flow path, upstream and downstream may be defined in respect of a direction of flow in the flow path, e.g. with an outlet being downstream of an inlet.
As used herein, a "delivery system" may be a system operative to deliver an aerosol to a user. The delivery system may include a mouthpiece and a flow path. The delivery system may be at least partly within the aerosol generating component.
As used herein, a "flow" may refer to a flow in a flow path. A flow may include aerosol generated from the precursor. The flow may include air, which may be induced into the flow path via a puff by a user.
As used herein, a "puff" (or "inhale" or "draw") by a user may refer to expansion of lungs and/or oral cavity of a user to create a pressure reduction that induces flow through the flow path.
As used herein, an "aerosol generating unit" may refer to a device configured to generate an aerosol from a precursor. The aerosol generating unit may include a unit to generate an aerosol directly from the precursor (e.g. an atomiser including an ultrasonic system). A plurality of aerosol generating units to generate a plurality of aerosols (for example, from a plurality of different aerosol precursors) may be present in an aerosol generating apparatus.
As used herein, an "ultrasonic generator" may refer to a piezoelectric transducer capable of vibrating at ultrasonic frequencies, i.e., at frequencies greater than 20kHz. In some examples, the piezoelectric transducer may be capable of vibrating at even higher frequencies, e.g., at frequencies of 100 kHz or above, 500 kHz or above, 1 MHz or more, 2 MHz or more, 5 MHz or more, or 10 MHz or more. The piezoelectric transducer may be adapted to vibrate in response to a driving signal, and in particular adapted to vibrate at the frequency of the driving signal. The driving signal may be generated, for example, using direct digital synthesis or any other suitable method.
As used herein, a "piezoelectric transducer" may refer to an ultrasonic transducer comprising a piezoelectric crystal, which generates a mechanical strain internally in response to an electric field. A rapidly changing electric field, such as an ultrasonic frequency driving signal, results in rapidly changing mechanical strain within the piezoelectric crystal causing it to vibrate. The piezoelectric transducer will have an aerosolisation surface from which the aerosol is generated. The aerosolisation surface typically faces into an aerosolisation chamber.
As used herein, an "aerosol generating component" may refer to a component that includes an aerosol precursor. The component may include an aerosol generating unit e.g. it may be arranged as a cartomizer. The component may include a mouthpiece. The component may include an information carrying medium. The component may include a storage portion, e.g. a reservoir or tank, for storage of the aerosol precursor.
With liquid or gel implementations of the aerosol precursor, e.g. an e-liquid, the component may be referred to as a "capsule" or a "pod" or an "e-liquid consumable". In some embodiments, the aerosol precursor component may be affixed to the device body to form the aerosol generating apparatus. In these embodiments, the reservoir/tank may be refillable.
The aerosol generating component e.g. the capsule, pod, or consumable may be for releasable coupling to a device body to form the aerosol generating apparatus.
The device body may comprise a power supply for powering the aerosol generating unit.
As used herein, an "information carrying medium" may include one or more arrangements for storage of information on any suitable medium. Examples include: a computer readable medium; a Radio Frequency Identification (RFID) transponder; codes encoding information, such as optical (e.g. a bar code or QR code) or mechanically read codes (e.g. a configuration of the absence or presents of cutouts to encode a bit, through which pins or a reader may be inserted).
As used herein, "electrical circuitry" may refer to one or more electrical components, examples of which may include: an Application Specific Integrated Circuit (ASIC) or other programmable logic; electronic/electrical componentry (which may include combinations of transistors, resistors, capacitors, inductors etc); one or more processors (e.g., the circuitry structure of the processor); a non-transitory memory (e.g. implemented by one or more memory devices), that may store one or more software or firmware programs; a combinational logic circuit; interconnection of the aforesaid. The electrical circuitry may be located entirely at the apparatus, or distributed between the apparatus and/or on one or more external devices in communication with the apparatus, e.g. as part of a system.
As used herein, a "processing resource" (or "processor" or "controller") may refer to one or more units for processing data, examples of which may include an ASIC, microcontroller, FPGA, microprocessor, digital signal processor (DSP) capability, state machine or other suitable component. A processing resource may be configured to execute a computer program, e.g. which may take the form of machine readable instructions, which may be stored on a non-transitory memory and/or programmable logic. The processing resource may have various arrangements corresponding to those discussed for the circuitry, e.g. on-board and/or off board the apparatus as part of the system. As used herein, any machine executable instructions, or computer readable media, may be configured to cause a disclosed method to be carried out, e.g. by a aerosol generating apparatus or system as disclosed herein, and may therefore be used synonymously with the term method.
As used herein, an "external device" (or "peripheral device") may include one or more electronic components external to an aerosol generating apparatus. Those components may be arranged at the same location as the aerosol generating apparatus or remote from the apparatus. An external device may comprise electronic computer devices including: a smartphone; a PDA; a video game controller; a tablet; a laptop; or other like device.
As used herein, a "computer readable medium/media" (or "memory" or "data storage") may include any medium capable of storing a computer program, and may take the form of any conventional non-transitory memory, for example one or more of: random access memory (RAM); a CD; a hard drive; a solid state drive; a memory card; a DVD. The memory may have various arrangements corresponding to those discussed for the circuitry /processor. The present disclosure includes a computer readable medium configured to cause an apparatus or system disclosed herein to perform a method as disclosed herein.
As used herein, a "communication resource" (or "communication interface") may refer to hardware and/or firmware for electronic information/data transfer. The communication resource may be configured for wired communication ("wired communication resources") or wireless communication ("wireless communication resource"). Wireless communication resources may include hardware to transmit and receive signals by radio and may include various protocol implementations e.g. the 802.11 standard described in the Institute of Electronics Engineers (IEEE) and Bluetooth^™ from the Bluetooth Special Interest Group of Kirkland Wash. Wired communication resources may include; Universal Serial Bus (USB); High-Definition Multimedia Interface (HDMI) or other protocol implementations. The apparatus may include communication resources for wired or wireless communication with an external device.
As used herein, a "network" (or "computer network") may refer to a system for electronic information/data transfer between a plurality of apparatuses/devices. The network may, for example, include one or more networks of any type, which may include: a Public Land Mobile Network (PLMN); a telephone network (e.g. a Public Switched Telephone Network (PSTN) and/or a wireless network); a local area network (LAN); a metropolitan area network (MAN); a wide area network (WAN); an Internet Protocol Multimedia Subsystem (IMS) network; a private network; the Internet; an intranet.
It will be appreciated that any of the disclosed methods (or corresponding apparatuses, programs, data carriers, etc.) may be carried out by either a host or client, depending on the specific implementation (i.e. the disclosed methods/apparatuses are a form of communication(s), and as such, may be carried out from either 'point of view', i.e. in corresponding to each other fashion). Furthermore, it will be understood that the terms "receiving" and "transmitting" encompass "inputting" and "outputting" and are not limited to an RF context of transmitting and receiving electromagnetic (e.g. radio) waves. Therefore, for example, a chip or other device or component for realizing embodiments could generate data for output to another chip, device or component, or have as an input data from another chip, device, or component, and such an output or input could be referred to as "transmit" and "receive" including gerund forms, that is, "transmitting" and "receiving," as well as such "transmitting" and "receiving" within an RF context.
Referring to Fig. 1, an example aerosol generating apparatus 1 includes a power supply 2, for supply of electrical energy. The apparatus 1 includes an aerosol generating unit 4 that is driven by the power supply 2. The power supply 2 may include an electric power supply in the form of a battery and/or an electrical connection to an external power source. The apparatus 1 includes a precursor 6, which in use is aerosolised by the aerosol generating unit 4 to generate an aerosol. The aerosol generating unit 4 includes a piezoelectric transducer (discussed below) configured to induce, by vibration of the piezoelectric transducer i.e. vibration of an aerosolisation surface of the piezoelectric transducer, cavitation in the precursor 6. Collapse of the cavities in the precursor 6 induces a shock that propagates through the liquid precursor 6. This shock disturbs a surface of the liquid precursor 6 that interfaces with air within an aerosolisation chamber of the aerosol generating apparatus 1 (which in turn is in fluid communication with an airflow path within the aerosol generating apparatus). These disturbances take the form of ripples, also known as capillary waves, that form ligaments at the peaks of the ripples/waves, pinch off and expel droplets from the liquid precursor 6 into the airflow path, thereby aerosolising the precursor 6 to generate the aerosol. The apparatus 2 includes a delivery system 8 for delivery of the aerosol to a user.
Electrical circuitry (not shown in figure 1) may be implemented to control the interoperability of the power supply 2 and aerosol generating unit 4.
Fig. 2 shows an implementation of the apparatus 1 of Fig. 1, where the aerosol generating apparatus 1 is configured to generate aerosol from a liquid precursor.
In this example, the apparatus 1 includes a device body 10 and a consumable 30.
In this example, the body 10 includes the power supply 2. The body may additionally include any one or more of electrical circuitry 12, a memory 14, a wireless interface 16, one or more other components 18.
The electrical circuitry 12 may include a processing resource for controlling one or more operations of the body 10 and consumable 30, e.g. based on instructions stored in the memory 14.
The wireless interface 16 may be configured to communicate wirelessly with an external (e.g. mobile) device, e.g. via Bluetooth.
The other component(s) 18 may include one or more user interface devices configured to convey information to a user and/or a charging port, for example (see e.g. Fig. 3).
The consumable 30 includes a storage portion implemented here as a tank 32 which stores the liquid precursor 6 (e.g. e-liquid). The consumable 30 also includes one or more air inlets 36, and a mouthpiece 38. The consumable 30 may include one or more other components 40.
The body 10 and consumable 30 may each include a respective electrical interface (not shown) to provide an electrical connection between one or more components of the body 10 with one or more components of the consumable 30. In this way, electrical power can be supplied to components of the consumable 30, without the consumable 30 needing to have its own power supply.
The piezoelectric transducer 34 of the aerosol generating unit 4 is arranged to be in electrical contact with one or more components of the body 10. For example, the power supply 2 may be configured to provide power to the piezoelectric transducer 34. Additionally or alternatively, the piezoelectric transducer 34 may be in electrical contact/communication with one or more of the electrical circuitry 12, memory 14, wireless interface 16 or one or more of the one or more other components 18 e.g., to receive instructions to adjust an operating parameter of the piezoelectric transducer 34 and/or to transmit data indicative of the operational parameters of the piezoelectric transducer 34.
Moreover, the piezoelectric transducer 34 is arranged to be in fluid communication with the tank 32 e.g. via a wick such that the liquid precursor can be provided to the aerosolisation surface of the piezoelectric transducer 34.
In use, a user may activate the aerosol generating apparatus 1 when inhaling through the mouthpiece 38, i.e. when performing a puff. The puff, performed by the user, may initiate a flow through a flow path in the consumable 30 which extends from the air inlet(s) 36 to the mouthpiece 38 via a region (i.e. an aerosolisation chamber) in proximity to the piezoelectric transducer 34.
Activation of the aerosol generating apparatus 1 may be initiated, for example, by an airflow sensor in the body 10 which detects airflow in the aerosol generating apparatus 1 (e.g. caused by a user inhaling through the mouthpiece), or by actuation of an actuator included in the body 10. Upon activation, the electrical circuitry 12 (e.g. under control of the processing resource) may supply electrical energy from the power supply 2 to the piezoelectric transducer 34 of the aerosol generating unit 4, which may cause the piezoelectric transducer 34 to induce cavitation in the liquid precursor 6 drawn from the tank so as to produce an aerosol which is carried by the flow out of the mouthpiece 38.
In some examples, the consumable may include a wick, wherein a first portion of the wick extends into the tank 32 in order to draw liquid precursor 6 out from the tank 32 and wherein a second portion of the wick is arranged to convey the drawn liquid precursor 6 to the aerosolisation surface piezoelectric transducer 34of the aerosol generating unit 4.
In this example, the delivery system 8 is provided by the above-described flow path and mouthpiece 38.
In variant embodiments (not shown), any one or more of the precursor 6, air inlet(s) 36 and mouthpiece 38, may be included in the body 10. For example, the mouthpiece 36 may be included in the body 10 with the precursor 6 arranged as a separable cartomizer.
Figs. 3A and 3B show an example implementation of the aerosol generating apparatus 1 of Fig. 2. In this example, the consumable 30 is implemented as a capsule/pod, which is shown in Fig. 3A as being physically coupled to the body 10, and is shown in Fig. 3B as being decoupled from the body 10.
In this example, the body 10 and the consumable 30 are configured to be physically coupled together by pushing the consumable 30 into an aperture in a top end 11 the body 10, with the consumable 30 being retained in the aperture via an interference fit.
In other examples (not shown), the body 10 and the consumable 30 could be physically coupled together in other ways, e.g. by screwing one onto the other, through a bayonet fitting, or through a snap engagement mechanism, for example.
The body 10 also includes a charging port (not shown) at a bottom end 13 of the body 10.
The body 10 also includes a user interface device configured to convey information to a user. Here, the user interface device is implemented as a light 15, which may e.g. be configured to illuminate when the apparatus 1 is activated. Other user interface devices are possible, e.g. to convey information haptically or audibly to a user.
In this example, the consumable 30 has an opaque cap 31, a translucent tank 32 and a translucent window 33. When the consumable 30 is physically coupled to the body 10 as shown in Fig. 3A, only the cap 31 and window 33 can be seen, with the tank 32 being obscured from view by the body 10. The body 10 includes a slot 15 to accommodate the window 33. The window 33 is configured to allow the amount of liquid precursor 6 in the tank 32 to be visually assessed, even when the consumable 30 is physically coupled to the body 10.
Fig. 4 shows an example system 80 for managing an aerosol generating apparatus 1, such as those described above with reference to any of Figs. 1-3B.
The system 80 as shown in Fig. 1 includes a mobile device 82, an application server 84, an optional charging station 86, as well as the aerosol generating apparatus 1.
In this example, aerosol generating apparatus 1 is configured to communicate wirelessly, e.g. via Bluetooth^™, with an application (or "app") installed on the mobile device 2, via a wireless interface included in the aerosol generating apparatus 1 and via a wireless interface included in the mobile device 82. The mobile device 82 may be a mobile phone, for example. The application on the mobile phone is configured to communicate with the application server 84, via a network 88. The application server 84 may utilise cloud storage, for example.
The network 88 may include a cellular network and/or the internet.
In other examples, the aerosol generating apparatus 1 may be configured to communicate with the application server 84 via a connection that does not involve the mobile device 82, e.g. via a narrowband internet of things ("NB-loT") or satellite connection. In some examples, the mobile device 82 may be omitted from the system 80.
A skilled person would readily appreciate that the mobile device 82 may be configured to communicate via the network 88 according to various communication channels, preferably a wireless communication channel such as via a cellular network (e.g. according to a standard protocol, such as 3G or 4G) or via a WiFi network.
The app installed on the mobile device 82 and the application server 84 may be configured to assist a user with managing their aerosol generating apparatus 1, based on information communicated between the aerosol generating apparatus 1 and the app, information communicated directly between the aerosol generating apparatus 1 and the application server 84, and/or information communicated between the app and the application server 84.
The charging station 86 (if present) may be configured to charge (and optionally communicate with) the aerosol generating apparatus 1, via a charging port on the aerosol generating apparatus 1. The charging port on the smoking substitute device 10 may be a USB port, for example, which may allow the aerosol generating apparatus 1 to be charged by any USB-compatible device capable of delivering power to the aerosol generating apparatus 1 via a suitable USB cable (in this case the USB-compatible device would be acting as the charging station 86). Alternatively, the charging station could be a docking station specifically configured to dock with the aerosol generating apparatus 1 and charge the aerosol generating apparatus 1via the charging port on the aerosol generating apparatus 1.
Fig. 5 shows an example of a circuit for modelling the behaviour of a piezoelectric transducer 100 at the resonant frequency of the piezoelectric transducer 100. Example circuits for providing a driving signal to the piezoelectric transducer 100 are described below with reference to Figures 6 and 7.
The circuit includes a set of components connected in series with each other between a pair of terminals 110a, 110b, including: an inductor 120; a resistor 130; and an in-series capacitor 140. The set of series components are connected in parallel with an in-parallel capacitor 150. Each of the components of the circuit model different aspects of the electrical and mechanical behaviour of the piezoelectric transducer 100.
The mechanical vibration of the piezoelectric transducer 100 is modelled by the inductive reactance of the inductor 120, when the frequency of the electric signal driving the piezoelectric transducer 100 is at, or near, the resonant frequency of the piezoelectric transducer 100.
Internal losses associated with the operation of the piezoelectric transducer 100, such as mechanical damping and dielectric losses within the piezoelectric crystal of the transducer 100 are modelled by the resistor 130. The resistance value of the resistor 130 is linked to the quality factor (or Q-factor) of the resonance of the piezoelectric transducer 100, which affects the amplitude and the sharpness of the resonance peak in the transducer's 100 frequency response.
Capacitive mechanical and electrical characteristics of the piezoelectric transducer 100 are modelled by the in-series capacitor 140.
Inherent dielectric properties of the material forming the piezoelectric transducer, e.g., due to the structure of the piezoelectric material between electrodes of the transducer 100 are modelled by the in-parallel capacitor 150. This inherent "parallel" capacitance significantly influences the resonance behaviour of the piezoelectric transducer 100, for example, by affecting the total impedance of the circuit at resonance when combined with the inductive and resistive elements (as modelled by the inductor 120 and the resistor 130).
As an example, the circuit of Figure 5 may be suitable for modelling a typical piezoelectric transducer 100 with a resonance frequency of approximately 3 MHz, by providing the inductor 120 with an inductance of 3 µH, the resistor 130 with a resistance of 4 Ω, the in-series capacitor 140 with a capacitance of 938 pF, and the in-parallel capacitor 150 with a capacitance of 1 nF.
Fig. 6 shows a portion of a conventional driving circuit 200 for driving a piezoelectric transducer 100 using an H-bridge. The H-bridge is defined by four switches 210, 220, 230, 240 arranged in an 'H-shaped' arrangement around the piezoelectric transducer 100. In the example shown in Fig. 6, the four switches 210, 220, 230, 240 are each defined by a respective MOSFET. The H-bridge of Fig. 6 is useful for rapidly changing the polarity of a voltage applied to the piezoelectric transducer 100, thereby driving piezoelectric vibrations in the transducer 100.
H-bridge circuits such as the one depicted in Fig. 6 may face challenges in the context of a user device such as the aerosol-generating apparatus 1 described herein.
For example, high-frequency switching of the four (MOSFET) switches 210, 220, 230, 240 may result in significant power and heat dissipation, generating considerable amounts of heat. This heat can degrade component performance over time and shorten the lifespan of the whole H-bridge, including the piezoelectric transducer 100. Moreover, the power dissipation may represent an undesirable inefficiency in the circuit performance of the H-bridge.
There may also be a risk of a latch-up type short-circuit in which one or more parts of the H-bridge circuit become uncontrollably conductive, thereby compromising the circuit's reliability. In the extreme, latch-up can lead to total circuit failure.
Electromagnetic interference may also be a concern when considering the implementation of a H-bridge. The rapid switching inherent in the operation of the four (MOSFET) switches 210, 220, 230, 240 can generate interference that can disrupt the operation of other electronic components/devices in the vicinity of the H-bridge.
Additionally, the operation of the piezoelectric transducer 100 (or indeed any component having an inductive load), can lead to high-voltage spikes in the current flowing through the circuit. Such spikes risk causing severe damage to the transistors used to embody the four MOSFET switches 210, 220, 230, 240 of the H-bridge shown in Fig. 6.
Furthermore, to induce high-frequency (e.g., ultrasonic) vibrations in the piezoelectric transducer 100, very precise and potentially complex timing control of the H-bridge is required. In particular, if both the first and second switches 210, 220, both the first and third switches 210, 230, both the second and fourth switches 220, 240 or both the third and fourth switches 230, 240 are open at the same time, there is a significant risk of shoot-through, or crossover, current that risks damaging the switches as the shoot-through current passes through and reduces the power efficiency of the H-bridge.
Fig. 7 shows an example of an improved driving circuit 300 for driving a piezoelectric transducer 100 using a single (MOSFET) switch 310.
The driving circuit 300 of Fig. 7 comprises a gate power source 320 configured to controllably apply a voltage to the gate of the MOSFET switch 310 to controllably open and close the MOSFET switch 310. The gate power source 320 may be connected to a clock, or may be an oscillator circuit so as to cyclically open and close the MOSFET switch 310 at a selected frequency.
The driving circuit 300 further comprises a driving power source 330 configured to supply power through the driving circuit 300. When the MOSFET switch 310 is closed, the current supplied by the driving power source 300 bypasses the piezoelectric transducer and flows into the source of the MOSFET switch 310 and out from the drain of the MOSFET switch 310 to ground. The driving power source 330 may be the power supply 2 discussed above in relation to Fig. 1.
When the MOSFET switch 310 is open, the current supplied by the driving power source 300 flows through the piezoelectric transducer 100 to ground, thereby inducing vibration in the piezoelectric transducer.
Application of a current to a piezoelectric transducer 100 induces a mechanical response in the transducer 100. Typically, the current applied to the piezoelectric transducer 100 is an alternating current so as to induce oscillatory vibrations in the piezoelectric transducer 100. Upon application of a current in a first polarity, opposite faces of the piezoelectric crystal of the transducer 100 respond by expanding, or bulging, outwards to define respective convex surfaces. Conversely, upon application of current in a second polarity opposite to the first polarity, the opposite faces of the piezoelectric crystal of the transducer 100 respond by contracting, or drawing, inwards to define respective concave surfaces. In the context of an aerosol-generating apparatus 1, it may be advantageous to only drive the piezoelectric transducer 100 in the first polarity so that physical contact between the transducer 100 and the at least some of the liquid precursor 6 can be maintained. Maintaining this physical contact improves the power efficiency of the inducement of cavitation in the liquid precursor 6, and therefore improves the efficiency of the generation of the aerosol. To this end, the driving signal provided by the driving power source 330 is preferably a direct current power source oscillating, at the piezoelectric transducer 100, between a maximum amplitude and a minimum (zero) amplitude with a frequency corresponding to the switching frequency of the MOSFET switch 310.
The driving circuit 300 may further comprise an inductor 350 connected in series with the piezoelectric transducer. The inductor 350 is arranged and configured with an inductance suitable for smoothing the current profile of the signal provided by the driving power source 330 such that the piezoelectric transducer 100 is not subjected to abrupt step-changes in the voltage and current flowing therethrough. This smoothing of the current profile consequently reduces the risk of damage to the piezoelectric transducer by reducing the risk of harmful voltage spikes.
The driving circuit 300 may further comprise one or more resistors 360, 370, 380 configured to limit the current flowing through the driving circuit.
Fig. 8 shows a block system diagram of an example aerosol generating apparatus 1 that includes a power supply 2, for supply of electrical energy. The apparatus 1 includes a first aerosol generating unit 4 that is driven by the power supply 2. The power supply 2 may include an electric power supply in the form of a (rechargeable) battery and/or an electrical connection to an external power source. The apparatus 1 includes a first aerosol precursor 6, which in use is aerosolised by the first aerosol generating unit 4 to generate a first aerosol. The first aerosol generating unit 4 includes a piezoelectric transducer (discussed elsewhere) configured to induce, by vibration of the piezoelectric transducer i.e. vibration of an aerosolisation surface of the piezoelectric transducer, cavitation in the first aerosol precursor 6. Collapse of the cavities in the first aerosol precursor 6 induces a shock that propagates through the first aerosol precursor 6. This shock disturbs a surface of the first aerosol precursor 6 that interfaces with air within an aerosolisation chamber of the aerosol generating apparatus 1 (which in turn is in fluid communication with an airflow path within the aerosol generating apparatus). These disturbances take the form of ripples, also known as capillary waves, that form ligaments at the peaks of the ripples/waves, pinch off and expel droplets from the first aerosol precursor 6 into the airflow path, thereby aerosolising the first aerosol precursor 6 to generate the first aerosol.
The apparatus 1 further includes a second aerosol generation unit 5 that is also driven by the power supply 2. The apparatus further includes a second aerosol precursor 7, which in use is aerosolised by the second aerosol generating unit 5 to generate a second aerosol. The second aerosol generating unit 5 includes a piezoelectric transducer configured to generate second aerosol from the second aerosol precursor 7 in the same manner as the piezoelectric transducer of the first aerosol generation unit 4 is configured to generate the first aerosol from the first aerosol precursor 6.
The apparatus 1 includes a delivery system 8 for delivery of the aerosol to a user.
The apparatus 1 includes a charging port 9 for connecting the power supply 2 to an external power source to charge the power supply 2.
Electrical circuitry (not shown in figure 1) may be implemented to control the interoperability of the power supply 2 and aerosol generating unit 4.
Fig. 9 shows an example of first and second driving circuits 300, 301 for driving respective piezoelectric transducers 100, 101 of the aerosol generating apparatus 1. Each of the first and second driving circuits are, individually, as set out above in relation to Fig. 7.
In other words, the first driving circuit 300 comprises a gate power source 320 operably connected to a MOSFET switch 310. The gate power source 320 may be connected to a clock, or may be an oscillator circuit so as to cyclically open and close the MOSFET switch 310 at a selected (first driving) frequency.
The first driving circuit 300 further comprises a driving power source 330, an inductor 350, and one or more resistors 360, 370, 380.
The first driving circuit 300 further comprises a first three-way switch 395 that is configurable into and between any combination of, or all of: (i) a driving configuration, (ii) a charging configuration, or (iii) an on-charge driving configuration.
When the first three-way switch 395 is in the driving configuration, the first driving circuit 300 is configured such that power is conveyable from the driving power source 330 to the piezoelectric transducer 100.
When the first three-way switch 395 is in the charging configuration, the first driving circuit 300 is configured such that power is conveyable from a charging port 390 to the driving power source 330.
When the first three-way switch 395 is in the on-charge driving configuration, the first driving circuit 300 is configured such that power is conveyable from the charging port 390 to the piezoelectric transducer 100.
The second driving circuit 301 comprises a gate power source 321 operably connected to a MOSFET switch 311. The gate power source 321 may be connected to a clock, or may be an oscillator circuit so as to cyclically open and close the MOSFET switch 311 at a selected (second driving) frequency. As discussed above, in some examples, the first and second gate power source 320, 321 may be either a common gate power source or respectively different power sources.
The second driving circuit 301 further comprises a driving power source 331, an inductor 351, and one or more resistors 361, 371, 381.
The second driving circuit 301 further comprises a second three-way switch 396 that is configurable into any of (i) a driving configuration, (ii) a charging configuration, or (iii) an on-charge driving configuration.
When the second three-way switch 396 is in the driving configuration, the second driving circuit 301 is configured such that power is conveyable from the driving power source 331 to the piezoelectric transducer 101.
When the second three-way switch 396 is in the charging configuration, the second driving circuit 301 is configured such that power is conveyable from the charging port 390 to the driving power source 331.
When the second three-way switch 396 is in the on-charge driving configuration, the second driving circuit 301 is configured such that power is conveyable from the charging port 390 to the piezoelectric transducer 101.
In some implementations, when one of the first and second three-way switches 395, 396 is in the charging configuration, the other may be in the on-charge driving configuration.
Figs. 10a to 10c show exemplary configurations of the first and second three-way switches 395, 396 suitable for switching the driving circuits 300, 301 of Fig. 9 between the driving configuration (Fig. 10a), the charging configuration (Fig. 10b) and the on-charge driving configuration (Fig. 10c).
Referring to Fig. 11 there is provided an aerosol generating apparatus 400 that comprises a first tank 410 containing a first liquid aerosol precursor and a second tank 420 containing a second liquid aerosol precursor. In the example shown in Fig. 11, the first liquid aerosol precursor in the first tank 410 comprises a nicotine formulation and the second liquid aerosol precursor in the second tank 420 comprises a flavour formulation, i.e., a nicotine free formulation.
The aerosol generating apparatus further comprises an aerosol generation unit 430 in fluid communication with the first tank 410 and the second tank 420 such that the first liquid aerosol precursor is communicated from the first tank 410 to the aerosol generation unit 430 and such that the second liquid aerosol precursor is communicated from the second tank 420 to the aerosol generation unit 430.
In the example shown in Fig. 11, the aerosol generation unit 430 comprises a first aerosol generator 431 and a second aerosol generator 432, each of which comprises a piezoelectric transducer 100 and a drive circuit 300 as described above.
The first aerosol generator 431 is in fluid communication with the first tank 410 in order to communicate the first liquid aerosol precursor from the first tank 410to the first aerosol generator 431, and in particular to the aerosolization surface of the piezoelectric transducer of the first aerosol generator 431, for example by way of a wick.
The second aerosol generator 432 is in fluid communication with the second tank 420 in order to communicate the second liquid aerosol precursor from the second tank 420 to the second aerosol generator 432, and in particular to the aerosolization surface of the piezoelectric transducer of the second aerosol generator 432, for example by way of a wick.
The aerosol generation unit 430, and in particular, the first aerosol generator 431 and the second aerosol generator 432 are communicatively linked to a controller 440 adapted to control the activation of the first aerosol generator 431 and the second aerosol generator 432 according to the methods described below. The controller 400 may be embodied as electrical circuitry that is part of the aerosol generating apparatus 400 and/or as electrical circuitry that is distributed more widely over one or more components of the aerosol generating system 80. In particular, the controller 440 is adapted to control the first aerosol generator 431 and the second aerosol generator 432 in order to adjust the ratio of first aerosol to second aerosol within an aerosol mixture generated by the aerosol generation unit 430.
The aerosol generating apparatus 400 comprises an inhalation sensor 450 communicatively linked to the controller and adapted to sense an inhalation of the user. The controller 440 is adapted to activate the first aerosol generator 431 and the second aerosol generator 432 in response to an inhalation of the user sensed by the inhalation sensor 450.
In addition, the inhalation sensor 450 is adapted to determine the strength of a given inhalation of the user. For example, the inhalation sensor 450 may be adapted to sense a relative change in pressure generated by the user inhaling and this relative change in pressure may be used to determine the relative strength of an inhalation compared to an expected change in pressure caused by an average inhalation strength.
The controller 440 is further adapted to a control signal to cause the aerosol generation unit 430 to adjust a ratio of an amount of first aerosol generated in response to the inhalation to an amount of second aerosol generated in response to the inhalation based on the strength of the inhalation as determined by the inhalation sensor 450.
Referring to Fig. 12 there is provided an aerosol generating apparatus 500 that comprises a first aerosol generator 510 for generating a first aerosol from a first formulation and a second aerosol generator 520 for generating a second aerosol from a second formulation, different from the first formulation.
Each of the first aerosol generator 510 and the second aerosol generator 520 comprises a piezoelectric transducer 100 and a drive circuit 300 as described above.
The first aerosol generator 510 is in fluid communication with a first tank containing a first liquid aerosol precursor, which may be a nicotine formulation, in order to communicate the first liquid aerosol precursor from the first tank to the first aerosol generator 510, and in particular to the aerosolization surface of the piezoelectric transducer of the first aerosol generator 510, for example by way of a wick.
The second aerosol generator 520 is in fluid communication with a second tank containing a second liquid aerosol precursor, which may be a flavour formulation, in order to communicate the second liquid aerosol precursor from the second tank to the second aerosol generator 520, and in particular to the aerosolization surface of the piezoelectric transducer of the second aerosol generator 520, for example by way of a wick.
Both the first aerosol generator 510 and the second aerosol generator 520 are communicatively linked to a controller 530 adapted to control the activation of the first aerosol generator 510 and the second aerosol generator 520 according to the methods described below. The controller 530 may, for example, be embodied as electrical circuitry that is part of the aerosol generating apparatus 400 and/or as electrical circuitry that is distributed more widely over one or more components of the aerosol generating system 80.
Optionally, the aerosol generating apparatus 500 comprises an inhalation sensor 540 communicatively linked to the controller and adapted to sense an inhalation of the user. The controller 530 may be adapted to activate the first aerosol generator 510 and the second aerosol generator 520 in response to an inhalation of the user sensed by the inhalation sensor 540. The inhalation sensor may be adapted to measure an inhalations strength of the user, for example as a pressure measurement.
Referring to Fig. 13 there is provided an aerosol generating apparatus 600 that comprises a replaceable cartridge 610 and an aerosol generating device 650 adapted to receive the replaceable cartridge 610.
In the example shown in Fig. 13, the replaceable cartridge 610 comprises a first tank 612 containing a first liquid aerosol precursor and a second tank 614 containing a second liquid aerosol precursor. In the example shown in Fig. 13, the first liquid aerosol precursor in the first tank 612 comprises a nicotine formulation and the second liquid aerosol precursor in the second tank 614 comprises a flavour formulation, i.e., a nicotine free formulation.
The aerosol generating apparatus further comprises an aerosol generation unit 616 in fluid communication with the first tank 612 and the second tank 614 such that the first liquid aerosol precursor is communicated from the first tank 612 to the aerosol generation unit 616 and such that the second liquid aerosol precursor is communicated from the second tank 614 to the aerosol generation unit 616.
In the example shown in Fig. 13, the aerosol generation unit 616 comprises a first aerosol generator 618 and a second aerosol generator 620, each of which comprises a piezoelectric transducer 100 and a drive circuit 300 as described above.
The first aerosol generator 618 is in fluid communication with the first tank 612 in order to communicate the first liquid aerosol precursor from the first tank 612 to the first aerosol generator 618, and in particular to the aerosolization surface of the piezoelectric transducer of the first aerosol generator 618, for example by way of a wick.
The second aerosol generator 620 is in fluid communication with the second tank 614 in order to communicate the second liquid aerosol precursor from the second tank 614 to the second aerosol generator 620, and in particular to the aerosolization surface of the piezoelectric transducer of the second aerosol generator 620, for example by way of a wick.
In the example shown in Fig. 8, the replaceable cartridge further comprises a cartridge memory unit 622 adapted to store a set of driving parameters of the aerosol generating unit 616. In particular, the cartridge memory unit 622 stores a first subset of one or more driving parameters for driving the first aerosol generator 618 and a second subset of one or more driving parameters for driving the second aerosol generator 620.
For driving the piezoelectric transducers of the first 618 and second 620 aerosol generators, the first and second subsets of one or more driving parameters comprise: a driving frequency; a driving duty cycle; and a driving power. The driving frequency for the first aerosol generator 618, i.e., the first driving frequency (for example 3MHz), may be higher than the driving frequency for the second aerosol generator 620, i.e., the second driving frequency (for example 1.5MHz).
In the example shown in Fig. 8, the replaceable cartridge 610 further comprises a cartridge communication unit 624 adapted to wirelessly communicate the set of one or more driving parameters from the cartridge memory unit 622 to a device communication unit 652 on the aerosol generating device 650 for driving the aerosol generating unit.
The aerosol generation unit 616, and in particular, the first aerosol generator 618 and the second aerosol generator 620 are communicatively linked, via a wired connection 653 between the replaceable cartridge 610 and the aerosol generating device 650, to a controller 654 adapted to generate a control signal for causing the drive circuit to drive the aerosol generating unit 646 according to the set of one or more driving parameters received from the replaceable cartridge 610. The controller 654 may, for example, be embodied as electrical circuitry that is part of the aerosol generating apparatus 400 and/or as electrical circuitry that is distributed more widely over one or more components of the aerosol generating system 80.
Fig. 14 shows an exemplary frequency response in the current flowing through a piezoelectric transducer 100. As can be seen in the current response of the piezoelectric transducer 100, depicted in Fig. 14, this particular piezoelectric transducer 100 exhibits a resonant response when a driving signal having a driving frequency of approximately 3 MHz. In other words, the fundamental resonant frequency of piezoelectric transducer 100 is approximately 3 MHz.
Fig. 15 shows two exemplary frequency responses in the current flowing through a piezoelectric transducer 100. As can be seen in the first current response 94 of the piezoelectric transducer 100, depicted in Fig. 8, this particular piezoelectric transducer 100 exhibits a resonant response when a driving signal having a driving frequency of 3 MHz is applied. In other words, the fundamental resonant frequency of piezoelectric transducer 100 is 3 MHz or approximately 3 MHz.
The second current response 96 represents the change in resonant frequency of the same piezoelectric transducer 100, for example after an extended period of use, where the resonant response is now achieved when a driving signal having a driving frequency of 3.25 MHz or approximately 3.25 MHz is applied.
Below, a series of methods of controlling the operation of an aerosol-generating apparatus 1 is described. In the context of these methods, data that is measured and/or obtained from a source may be received by the user device 82 for the purpose of generating instructions for execution by the aerosol-generating apparatus 1. Operations in the methods described below that are carried out by the aerosol-generating apparatus may be carried out in response to execution of correspondingly generated instructions that are generated by an application installed on the user device 82 and subsequently transmitted to the aerosol generating apparatus 1 for execution.
Figs. 16a-16c show how the voltage response of the piezoelectric transducer 100 changes as the duty cycle of the driving signal is adjusted. As discussed above, adjusting the duty cycle of a driving cycle facilitates control of capacitive effects (e.g., pseudo-capacitive discharge that can be seen as the spike in voltage following each peak in Fig. 16a) that arise from the inherent dielectric properties of the material from which the piezoelectric transducer 100 is formed.
Fig. 16a shows that, for a duty cycle of 50%, these capacitive effects are particularly pronounced, while they are significantly mitigated for a duty cycle of 40% (as shown in Fig. 16b), and entirely eliminated for a duty cycle of 25% (as shown in Fig. 16c). It is, therefore, demonstrably possible to controllably adjust the duty cycle across a range of values to balance the impact of inherent dielectric capacitance of the piezoelectric transducer 100 (represented as the post-peak voltage spike in Figs. 16a and 16b) against a reduction in the energy propagated into the aerosol precursor 6 by vibration of the piezoelectric transducer 100 (represented by the area under each peak in Figs. 16a-c).
Fig. 17 shows a method for controlling an aerosol generating apparatus 1.
In a first operation 1000, the method involves determining a resonant frequency (e.g., the fundamental resonant frequency) of the piezoelectric transducer 100. A method for determining the resonant frequency is described below in relation to Fig. 18.
The method of Fig. 17 further comprises, in an operation 1100, providing a driving signal to drive the piezoelectric transducer 100 at an initial driving frequency. The piezoelectric transducer 100 is configured to exhibit a vibratory response to the driving signal in accordance with the initial driving frequency. The driving signal may be provided to the piezoelectric transducer 100 by a control unit of the aerosol generating apparatus 1 and/or by a remote device communicatively connectable to the aerosol generating apparatus 1 (e.g., via a communications interface of the aerosol generating apparatus).
The method further comprises, in an operation 1200, receiving a control signal with instructions for adjusting the driving signal encoded therein. The control signal may be received by a control unit of the aerosol generating apparatus 1 e.g., from a remote device 82 that is communicatively connectable to the control unit (and to the aerosol generating apparatus 1). Alternatively, the control signal may be received by a remote device 82 that is communicatively connectable to the control unit e.g., from a remote server 84 and/or network 88.
The control signal may be generated and/or determined having instructions 1250 for adjusting the driving signal encoded therein. Inputs and methods for determining the instructions 1250 is described below in relation to Fig. 19.
The method further comprises, in an operation 1300, adjusting the driving signal so as to modify one or more parameters of the aerosol generated by the aerosol generating apparatus 1. Adjusting the driving signal may involve one or more of: in an operation 1302, adjusting the driving frequency of the driving signal; in an operation 1304, adjusting the duty cycle of the driving signal; and/or in an operation 1306, adjusting the power level of the driving signal.
Adjusting, or tuning, the driving frequency at which the driving signal drives the piezoelectric transducer 100, allows the controllable adjustment of one or more properties of the aerosol generated by the aerosol generating apparatus 1 - e.g., according to a user's preference, manufacturer/provider's recommendation, and/or regulatory requirement. Adjusting the driving frequency may be particularly suitable for adjusting an average size of droplets of the aerosol precursor 6 entrained in the generated aerosol and/or a distribution of the size of said droplets. The inventors have observed that the frequency of the driving signal is a parameter that directly affects the average size of droplets in the aerosol generated by the aerosol generating apparatuses 1 described herein. In particular, when driving the piezoelectric transducer 100with a driving signal having a relatively higher driving frequency, a relatively smaller average droplet size is observed. This observation is consistent with the physical mechanism for cavitation described in Kooij et al. Sci. Rep., 9, 6128 (2019), the entirety of which is incorporated herein by reference.
Adjusting the duty cycle of the driving signal facilitates control of capacitive effects (e.g., pseudo-capacitive discharge) that arise from the inherent dielectric properties of the material from which the piezoelectric transducer 100 is formed (as can be seen e.g., in the spikes of Figs. 16a and 16b. For example, by appropriate control/tuning of the duty cycle, these capacitive effects may be limited or even entirely eliminated so as to ensure a more precise control of the vibrations of the piezoelectric transducer 100, and consequently a more reliable control of the one or more parameters of the generated aerosol.
In particular, by reducing (or even eliminating) the capacitive discharge of the piezoelectric transducer 100, the vibratory response of the piezoelectric transducer 100 to the driving signal can be controlled such that the oscillations of the piezoelectric transducer 100 include a reduced number of frequency components. In a particular example, control of the duty cycle may be optimised such that the vibratory response of the piezoelectric transducer includes just a single frequency component.
As the size of droplets in the generated aerosol is primarily affected by the frequency of the vibrations of the piezoelectric transducer 100, controlling the duty cycle may be used to control the number of frequency components in the piezoelectric transducer's vibratory response, and consequently control the distribution of droplet sizes in the generated aerosol.
Adjusting the power level of the driving signal facilitates control of the amount of cavitation induced by the piezoelectric transducer 100 in the aerosol precursor 6 located on the surface of the transducer. As such, adjusting the power level of the driving signal may facilitate the control of an amount of aerosol precursor 6 droplets entrained in the generated aerosol. In other words, controllably adjusting the power level of the driving signal facilitates control of the concentration of the generated aerosol.
Fig. 18 shows a method 1000 for identifying a resonant frequency (e.g., the fundamental resonant frequency) of a piezoelectric transducer 100. The method of Fig. 18 may be implemented as the corresponding operation 1000 described above in relation to Fig. 17.
The method 1000 of Fig. 18 comprises, in an operation 1002, providing a scanning signal that scans across a range of frequencies. As with the driving signal, the scanning signal may be provided to the piezoelectric transducer 100 by a control unit of the aerosol generating apparatus 1 and/or by a remote device that is communicatively connectable to the aerosol generating apparatus (e.g., via a communications interface thereof).
The method 1000 further comprises, in an operation 1004, measuring the response (e.g., the current response, the voltage response, or the impedance response) of the piezoelectric transducer 100 across the range of frequencies in the scanning signal. For example, this may involve obtaining measurements of the piezoelectric transducer's 100 response, such as the current response depicted in Fig. 8.
The method 1000 further comprises, in an operation 1006, identifying a resonant peak (e.g., the peak in the graph of Fig. 14) in the response to determine the corresponding resonant frequency (e.g., the fundamental resonant frequency) of the piezoelectric transducer 100.
Fig. 19 shows a method of determining instructions 1250 for encoding in a control signal of the method of Fig. 17. The method of Fig. 19 may be used to obtain the instructions input 1250 depicted and described above in relation to Fig. 17.
The method 1250 comprises, in an operation 1252, determining one or more parameters of the aerosol precursor 6. The one or more parameters of the aerosol precursor 6 may include one or more of: a density of the aerosol precursor 6, a viscosity of the aerosol precursor 6, a volume of the received aerosol precursor 6, and/or a molecular size of the aerosol precursor 6.
The method 1250 further comprises, in an operation 1254, determining one or more operational parameters of the aerosol generating apparatus 1. For example, the one or more operational parameters of the aerosol generating apparatus 1 may include one or more of: the initial driving frequency, an initial duty cycle associated with the driving signal, an initial power level associated with the driving signal and/or the vibratory response of the piezoelectric transducer 100 to the driving signal.
The method 1250 further comprises, in an operation 1256, determining one or more target aerosol parameters that the user/administrator/regulator desires the aerosol generated by the aerosol generating apparatus 1 to possess. The one or more target parameters of the generated aerosol may include one or more of: an amount of aerosol precursor entrained in the generated aerosol for each puff of the aerosol generating apparatus in use; an average size of the droplets of aerosol precursor entrained in the generated aerosol; and/or a distribution of the size of the droplets of aerosol precursor entrained in the generated aerosol.
Based on these (and, optionally, further inputs), the method 1250, in an operation 1258, further comprises determining the instructions to perform the necessary adjustment so as to achieve the one or more target aerosol parameters.
In other words, by providing information related to the parameters of the aerosol precursor 6, the operation of the aerosol generating apparatus 1, and the desired/target aerosol, it is possible to determine what adjustment to the driving signal is necessary to cause the aerosol generating apparatus 1 to generate an aerosol having the one or more target aerosol parameters associated therewith.
Fig. 20 shows another method for controlling an aerosol generating apparatus 1.
The method comprises, in an operation 1000, determining a resonant frequency (e.g., the fundamental resonant frequency) of a piezoelectric transducer. This operation may be implemented, for example, by carrying out the method of Fig. 10, as described above.
The method of Fig. 20 further comprises, in an operation 1010 selecting a first frequency from amongst the harmonic frequencies of the determined resonant frequency (optionally including the first harmonic - i.e., the determined resonant frequency itself).
The method further comprises, in an operation 1110, providing a first driving signal having a first driving frequency that matches the selected first frequency.
The method further comprises, in an operation 1020 selecting a second frequency from amongst the harmonic frequencies of the determined resonant frequency (optionally including the first harmonic - i.e., the determined resonant frequency itself).
The method further comprises, in an operation 1120, providing a second driving signal having a second driving frequency that matches the selected second frequency.
The first and second selected frequencies may be selected based on one or more of: the determined resonant frequency 1000 of the piezoelectric transducer, one or more parameters of the aerosol precursor 1252, and/or one or more target parameters 1254 of the aerosol generated by the aerosol generating apparatus.
In particular, the first and second selected frequencies may be selected two obtain an aerosol, generated by the aerosol generating apparatus 1, that has one or two populations of droplets (in terms of average droplet size). In other words, the first selected frequency may be selected to obtain a generated aerosol having a first average size of droplets of aerosol precursor 6 entrained in the aerosol, while the second selected frequency may be selected to obtain a generated aerosol having a second average size of droplets of aerosol precursor 6 entrained in the aerosol.
Subsequent to the provision of the first and second driving signals in operations 1110 and 1120, one or both of the second driving signals may be adjusted (either concurrently or independently) in accordance with operations 1260, 1210, 1310, 1312, 1314 and 1316 for the first driving signal, and in accordance with operations 1270, 1220, 1320, 1322, 1324 and 1326 for the second driving signal. In the context of Figs. 17 and 20, operations 1260 and 1270 of Fig. 20 correspond with operation 1250 of Fig. 17; operations 1210 and 1220 of Fig. 20 correspond with operation 1200 of Fig. 17; operations 1310 and 1320 of Fig. 20 correspond with operation 1300 of Fig. 17; operations 1312 and 1322 of Fig. 20 correspond with operation 1302 of Fig. 17; operations 1314 and 1324 of Fig. 20 correspond with operation 1304 of Fig. 17; and operations 1316 and 1326 of Fig. 20 correspond with operation 1306 of Fig. 17.
As such, the discussion above in relation to Figs. 17 to 19 is equally applicable to the adjustment of the first and/or second driving signal as set out in the method of Fig. 20.
Fig. 21 shows an exemplary method of controlling an aerosol generating apparatus.
The method comprises, in an operation 1400, determining whether the charging port 9, 390 is receiving power from an external power source.
The method may further comprise, in an operation 1410, receiving input (e.g., from a user via a user interface communicatively connected to a communications interface of the aerosol generating apparatus 1) indicative of which of the first and second driving circuits 300, 301 should be switched to the charging configuration.
The method further comprises, in an operation 1420, transmitting a first switching signal to switch one of the first and second driving circuits 300, 301 (e.g., the driving circuit selected in operation 1410) to the charging configuration.
The method may further comprise, in an operation 1430, transmitting a second switching signal to switch the other of the first and second driving circuits 300, 301 (e.g., the non-selected driving circuit) to the on-charge driving configuration.
Fig. 22 shows a method 1500 of controlling an aerosol generating apparatus, such as the aerosol generating apparatuses 1 described herein.
The method 1500 comprises, in an operation 1510, providing a surface priming signal to drive the piezoelectric transducer 100 to expel excess aerosol precursor from the surface of the piezoelectric transducer 100. In some examples, driving the piezoelectric transducer according to the surface priming signal may further expel excess aerosol precursor from at least a portion of a wick of the aerosol generating apparatus 1. The wick of the aerosol generating apparatus 1 is arranged to convey aerosol precursor 6 from the tank 32 to the piezoelectric transducer 100 for aerosolization according to the methods described herein and in Kooij et al., the entirety of which is incorporated by reference.
The method 1500 further comprises, in an operation 1520, providing a driving signal to drive the piezoelectric transducer 100 so as to generate aerosol from received aerosol precursor received on the surface of the piezoelectric transducer 100.
The method 1500 further comprises, in an operation 1530, monitoring a build-up of aerosol precursor 6 on the surface of the piezoelectric transducer 100. Monitoring the build-up of aerosol precursor 6 on the surface of the piezoelectric transducer 100 may involve monitoring a change in one or more of: a mass of received aerosol precursor 6 on the surface of the piezoelectric transducer 100, a volume of received aerosol precursor 6 on the surface of the piezoelectric transducer 100, a volume of aerosol generated per puff of the aerosol generating apparatus 1, when in use, and/or a concentration of aerosol generated per puff of the aerosol generating apparatus 1, when in use.
The method 1500 further comprises, in an operation 1540, determining whether the build-up of aerosol precursor 6 on the surface of the piezoelectric transducer 100 has crossed (e.g. is greater than) a predetermined threshold.
Crossing the predetermined threshold may involve a mass of received aerosol precursor 6 on the surface of the piezoelectric transducer 100 going above a predetermined mass threshold.
Additionally or alternatively, crossing the predetermined threshold may involve a volume of received aerosol precursor 6 on the surface of the piezoelectric transducer 100 going above a predetermined volume threshold.
Additionally or alternatively, crossing the predetermined threshold may involve a volume of aerosol generated per puff of the aerosol generating apparatus 1 going below a predetermined aerosol volume threshold.
Additionally or alternatively, crossing the predetermined threshold may involve a concentration of aerosol generated per puff of the aerosol generating apparatus going below a predetermined aerosol concentration threshold.
If the threshold(s) is not crossed, then the method may involve repeating the providing of the driving signal and the monitoring of the build-up of aerosol precursor 6 (as in operations 1520 and 1530).
If the threshold(s) is crossed, then the method may involve providing the surface priming signal (as in operation 1510) to expel excess aerosol precursor from the surface of the piezoelectric transducer 100 and, optionally, a portion of the wick.
Fig. 23 shows another method of controlling an aerosol generating apparatus 1.
Fig. 23 may comprise, in an operation 1500, carrying out the method of Fig. 22 to prime the surface of the piezoelectric transducer 100 so that the measurements and determinations described below are properly calibrated.
Fig. 23 comprises, in an operation 1600, measuring a response of the piezoelectric transducer 100 to one or more driving signals across a plurality of driving frequencies, for example by measuring the piezoelectric transducer's 100 response as the driving signal is scanned across a range of frequencies. Measuring the response of the piezoelectric transducer 100 may involve measuring one or more of the piezoelectric transducer's current response, impedance response or voltage response across the plurality or range of frequencies.
Fig. 23 further comprises, in an operation 1700, determining a profile of the aerosol precursor 6.
Determining a profile of the aerosol precursor 6 may involve comparing the measured response of the piezoelectric transducer 100 with one or more reference responses that may, for example, be stored in a database of reference responses - each of the reference responses being associated with an authorised aerosol precursor that is authorised for use with the aerosol generating apparatus 1.
Fig. 23 may further comprise, in an operation 1800, if it is determined that the aerosol precursor 6 is not an authorised aerosol precursor (i.e., is an unauthorised aerosol precursor such as an illicit or counterfeit aerosol precursor) disabling the aerosol generating apparatus 1. This disabling may be carried out to prevent damage to the aerosol generating apparatus and/or to the health of a user of the aerosol generating apparatus.
Fig. 23 may further comprise, in an operation 1900, if is determined that the aerosol precursor 6 is an authorised aerosol precursor, modifying one or more operational parameters of the aerosol generating apparatus according to target operational parameters for the identified authorised aerosol precursor 6. The one or more target operational parameters may, for example, be stored in the database with the one or more reference responses. The one or more operational parameters may include one or more of a driving frequency, a driving duty cycle, and/or a driving power of the driving signal.
Referring to Fig. 24, there is illustrated a method 2000 for controlling an aerosol generating apparatus 500.
In the particular method shown in Fig. 24, the method 2000 is a method for alternating between activating both the first aerosol generator 410 and the second aerosol generator 420 and activating only the first aerosol generator 410 over a series of inhalations of a user of the aerosol generating apparatus.
The method begins in step 2100 by activating both the first aerosol generator 410 and the second aerosol generator 420, for example, in response to an inhalation of the user. In response to a subsequent inhalation of the user, the method progresses to step 2200 by activating only the first aerosol generator 410.
After step 2200, the method returns to step 2100 and continues to alternate between activating both the first aerosol generator 410 and the second aerosol generator 420 and activating only the first aerosol generator 410 in response to the inhalations of the user.
Fig. 24 also shows several optional steps for controlling the aerosol generating apparatus 400, and specifically, for controlling the alternation between activating both the first aerosol generator 410 and the second aerosol generator 420 and activating only the first aerosol generator 410.
The alternation between activating both the first aerosol generator 410 and the second aerosol generator 420 and activating only the first aerosol generator 410 may occur on consecutive inhalations. Put another way, the method may switch between steps 2100 and 2200 with each inhalation of the user.
In the example shown in Fig. 24, the method 2000 further comprises optional step 2120 in which it is checked whether the number of inhalations where both the first aerosol generator 410 and the second aerosol generator 420 are activated has exceed a predetermined number of inhalations.
If the number of inhalations where both the first aerosol generator 410 and the second aerosol generator 420 are activated has not exceed the predetermined number of inhalations, the method returns to step 2100 and both the first aerosol generator 410 and the second aerosol generator 420 are activated in response to the next inhalation of the user.
If the number of inhalations where both the first aerosol generator 410 and the second aerosol generator 420 are activated has exceed the predetermined number of inhalations, the method may then progress to step 2200 where only the first aerosol generator 410 is activated in response to the next inhalation of the user.
In the example shown in Fig. 24, there is no equivalent step to step 2120 during the return from step 2200 to step 2100. Accordingly, the step 2200 of activating only the first aerosol generator 410 only occurs for a single inhalation.
In the example shown in Fig. 24, the method 2000 further comprises optional step 2140 in which it is checked whether an elapsed time since an inhalation last occurred has exceeded a predetermined period.
If the elapsed time since an inhalation last occurred has exceeded the predetermined period, and one inhalation session (or series of inhalations) has stopped and a new inhalation session has effectively begun, the method returns to step 2100 and both the first aerosol generator 410 and the second aerosol generator 420 are activated in response to the next inhalation of the user.
If the elapsed time since an inhalation last occurred has not exceeded the predetermined period, the method may then progress to step 2200 where only the first aerosol generator 410 is activated in response to the next inhalation of the user.
In the example shown in Fig. 24, the method 2000 further comprises optional step 2250 in which it is checked whether a control signal has been received at the aerosol generating apparatus 400, for example from mobile device 82. Step 2250 is outside of the alternating control loop as a control signal may be received at any time. The aerosol generating apparatus 400 may perform step 2250 regularly, for example between each inhalation of the user or at a regular time interval.
If no control signal has been received at the aerosol generating apparatus, the method progresses to step 2260 and the current activation state of the first aerosol generator 410 and the second aerosol generator 420, i.e., the activation states according to step 2100 or 2200, is maintained.
If a control signal has been received at the aerosol generating apparatus, the method either progresses to step 2100 or step 2200 according to the nature of the control signal.
Fig. 25 shows a schematic representation of the driving scheme for the first aerosol generator 410 and the second aerosol generator according to the methods shown in Fig. 24.
Graphs 2300 and 2400 shows the activation states of the first aerosol generator 410 and the second aerosol generator 420 for four inhalations.
In graph 2300, the aerosol generating apparatus 400 alternates between activating both the first aerosol generator 410 and the second aerosol generator 420, as represented by bars 2310 and 2330 which correspond to the first and third inhalations, and activating only the first aerosol generator 410, as represented by bars 2320 and 2340 which correspond to the second and fourth inhalations, on consecutive inhalations.
In graph 2400, the aerosol generating apparatus 400 alternates between activating both the first aerosol generator 410 and the second aerosol generator 420, as represented by bars 2410, 2420 and 2440 which correspond to the first, second and fourth inhalations, and activating only the first aerosol generator 410, as represented by bar 2330 which corresponds to the third inhalation, on nonconsecutive inhalations.
Referring to Fig. 26, there is illustrated a method 2500 for controlling an aerosol generating apparatus 400 according to an aspect of the invention.
In the particular method shown in Fig. 26, the method 2500 is a method for delaying the activation of the first aerosol generator 410 with respect to the activation of the second aerosol generator 420 for a first delay period in response to an inhalation of a user.
The method begins in step 2600 by activating the second aerosol generator 420, for example, in response to an inhalation of the user. During the same inhalation, whilst the second aerosol generator 420 is generating aerosol, the method progresses to step 2650 and waits for a first delay period to elapse.
After the first delay period has elapsed in step 2650, and during the same inhalation, the method progresses to step 2700 by activating the first aerosol generator 410, such that both the first aerosol generator 410 and the second aerosol generator 420 are activated for the remainder of the inhalation.
After the end of the inhalation, the method returns to step 2600 ready for the next inhalation to occur at which point the method 2500 will repeat as outlined above, i.e., by activating the second aerosol generator and then activating the first aerosol generator after a first delay period.
Fig. 26 also shows several optional steps for controlling the aerosol generating apparatus 400, and specifically, for controlling the timing of the activation of the first aerosol generator 410 and the second aerosol generator 420 relative to each other.
In some examples, the aerosol generating apparatus 400 is adapted to alternate the delaying of the activation of the first aerosol generator 410 with respect to the activation of the second aerosol generator 420 for the first delay period with delaying the activation of the second aerosol generator 420 with respect to the activation of the first aerosol generator 410 for a second delay period.
Thus, in the example shown in Fig. 26, the method may alternate between beginning at step 2600 and step 2700.
The alternation between delaying of the activation of the first aerosol generator 410 with respect to the activation of the second aerosol generator 420 for the first delay period with delaying the activation of the second aerosol generator 420 with respect to the activation of the first aerosol generator 410 for a second delay period may occur on consecutive inhalations. Put another way, the method may switch between beginning at steps 2600 and 2700 with each inhalation of the user.
In the example shown in Fig. 26, the method 2500 further comprises optional step 2750 in which a second delay period is introduced between activating the first aerosol generator and activating the second aerosol generator.
In the example shown in Fig. 26, the method 2500 further comprises optional step 2800 in which it is checked whether the number of inhalations where the activation of the first aerosol generator 410 is delayed with respect to the activation of the second aerosol generator 420 (i.e., the number of inhalations where the method has progress from step 2600 to step 2650 and then to step 2700) has exceed a predetermined number of inhalations.
If the number of inhalations where the second aerosol generator 420 is activated before the first aerosol generator 410 has not exceed the predetermined number of inhalations, the method returns to step 2600 and second aerosol generator 420 continues to be activated before the first aerosol generator 410 for the next inhalation of the user.
If the number of inhalations where the second aerosol generator 420 is activated before the first aerosol generator 410 has exceed the predetermined number of inhalations, the method may then progress to step 2700 where the first aerosol generator 410 will be activated before the second aerosol generator 420 for the next inhalation of the user, for example by way of the second delay period in step 2750.
In the example shown in Fig. 26, there is no equivalent step to step 2800 during the return from step 2600 to step 2700. Accordingly, the method running from step 2700 to 2600, via step 2750, (i.e., the delaying of the activation of the second aerosol generator with respect to the first aerosol generator) only occurs for a single inhalation.
In the example shown in Fig. 26, the method 2500 further comprises optional step 2805 in which it is checked whether an elapsed time since an inhalation last occurred has exceeded a predetermined period.
If the elapsed time since an inhalation last occurred has exceeded the predetermined period, and one inhalation session (or series of inhalations) has stopped and a new inhalation session has effectively begun, the method returns to step 2600 and the activation of the first aerosol generator is delayed with respect to the activation of the second aerosol generator in response to the next inhalation of the user.
If the elapsed time since an inhalation last occurred has not exceeded the predetermined period, the method may then progress to step 2700 where the first aerosol generator 410 will be activated before the second aerosol generator 420 for the next inhalation of the user, for example by way of the second delay period in step 2750.
In the example shown in Fig. 26, the method 2500 further comprises the optional step 2810 of measuring the inhalation duration of the user over a series of inhalations. In step 2820, an optimal delay period, which may be the first delay period in step 2650 or the second delay period in step 2750, for delaying the activation of the first/second aerosol generator with respect to the activation of the second/first aerosol generator based on the average inhalation duration of the user.
In the example shown in Fig. 26, the method 2500 further comprises optional step 2840 of measuring the inhalation strength of the user over a series of inhalations, for example by way of inhalation sensor 440. In step 2850, the delay period, which may be the first delay period in step 2650 or the second delay period in step 2750, is adjusted based on the average inhalation strength of the user.
Fig. 27 shows a schematic representation of the driving scheme for two aerosol generating units according to the method shown in Fig. 26.
Graphs 2900 and 2950 shows the activation states of the first aerosol generator 410 and the second aerosol generator 420 for two inhalations.
In graph 2900, the aerosol generating apparatus 400 delays the activation of the first aerosol generator 410 with respect to the activation of the second aerosol generator 420, such that for the first portion of the inhalations only the second aerosol generator 420 is active, as represented by bars 2910 and 2930, and for the second portion of the inhalations both the first aerosol generator 410 and the second aerosol generator 420 are active, as represented by bars 2920 and 2940.
In graph 2950, the aerosol generating apparatus 400 alternates between delaying the activation of the first aerosol generator 410 with respect to the activation of the second aerosol generator 420 in the first inhalation and delaying the activation of the second aerosol generator 420 with respect to the activation of the first aerosol generator 410 in the second inhalation.
In the first inhalation shown in graph 2950, the aerosol generating apparatus 400 delays the activation of the first aerosol generator 410 with respect to the activation of the second aerosol generator 420, such that for the first portion of the inhalation only the second aerosol generator 420 is active, as represented by bar 2960, and for the second portion of the first inhalation both the first aerosol generator 410 and the second aerosol generator 420 are active, as represented by bar 2970.
In the second inhalation shown in graph 2950, the aerosol generating apparatus 400 delays the activation of the second aerosol generator 420 with respect to the activation of the first aerosol generator 410, such that for the first portion of the inhalation only the first aerosol generator 410 is active, as represented by bar 2980, and for the second portion of the second inhalation both the first aerosol generator 410 and the second aerosol generator 420 are active, as represented by bar 2990.
Referring to Fig. 28, there is illustrated a method 3000 for controlling an aerosol generating apparatus 400 according to an aspect of the invention.
In the particular method shown in Fig. 28, the method 3000 is a method for modulating the activation of the first aerosol generator 410 and the second aerosol generator 420 over a single inhalation period of a user of the aerosol generating apparatus. Fig. 28 illustrates two different methods of modulating the activation of the first aerosol generator 410 and the second aerosol generator 420 over a single inhalation period, which are alternating an activation state of the first and second aerosol generators over the single inhalation period and delaying the activation state of one of the first and second aerosol generators with respect to another of the first and second aerosol generators over the single inhalation period.
In the example where modulating the activation of the first aerosol generator 410 and the second aerosol generator 420 comprises alternating an activation state of the first and second aerosol generators over the single inhalation period, the method begins in step 3010 by activating the second aerosol generator 420, for example, in response to an inhalation of the user.
The method may then progress to optional step 3020, where the second aerosol generator 420 is deactivated. Within the same inhalation period, the method progresses to step 3030, where the first aerosol generator 410 is activated. If the second aerosol generator 420 is deactivated in step 3020, then only the first aerosol generator 420 will be activated at step 3030. If the second aerosol generator 420 is not deactivated in step 3020, or step 3020 is not present, then both the first aerosol generator 410 and the second aerosol generator 420 will be activate at step 3030.
In the example where modulating the activation of the first aerosol generator 410 and the second aerosol generator 420 further comprises delaying the activation state of one of the first aerosol generator 410 and second aerosol generator 420 with respect to the other of the first aerosol generator 410 and the second aerosol generator 420, the method may progress to optional step 3050 and wait for a first delay period to elapse.
After the first delay period has elapsed in step 3050, and during the same inhalation, the method progresses to step 3030 by activating the first aerosol generator 410, such that for a period of time within the single inhalation period, neither aerosol generator is active between the activation of the second aerosol generator 420 and the first aerosol generator 410.
The method may then progress to optional step 3040, where the first aerosol generator 410 is deactivated. Still within the same inhalation period, the method may return to step 3010, where the second aerosol generator 420 is activated. If the first aerosol generator 410 is deactivated in step 3040, then only the second aerosol generator 420 will be activated at step 3010. If the first aerosol generator 410 is not deactivated in step 3040, or step 3040 is not present, then both the first aerosol generator 410 and the second aerosol generator 420 will be activate at step 3010.
In the example where modulating the activation of the first aerosol generator 410 and the second aerosol generator 420 further comprises delaying the activation state of one of the first aerosol generator 410 and second aerosol generator 420 with respect to the other of the first aerosol generator 410 and the second aerosol generator 420, the method may progress to optional step 3050 and wait for a second delay period to elapse.
After the second delay period has elapsed in step 3070, and during the same inhalation, the method returns to step 3010 by activating the second aerosol generator 420, such that for a period of time within the single inhalation period, neither aerosol generator is active between the activation of the first aerosol generator 410 and the second aerosol generator 420.
Thus, over a single inhalation period, the aerosol generating apparatus 400 may: alternate the activation of only the first aerosol generator 410 and only the second aerosol generator 420; alternate the activation of only the first aerosol generator 410 and both the first aerosol generator 410 and the second aerosol generator 420; and alternate the activation of only the second aerosol generator 420 and both the first aerosol generator 410 and the second aerosol generator 420.
Fig. 28 also shows several optional steps for controlling the aerosol generating apparatus 400, and specifically, for modulating the activation of the first aerosol generator 410 and the second aerosol generator 420.
In the example shown in Fig. 28, the method 3000 further comprises the optional step 3100 of measuring the inhalation duration of the user over a series of inhalations.
The method may progress to step 3110 where an optimal alternation frequency for alternating between activation states of the first and second aerosol generators is determined based on an average inhalation duration of the user. In step 3120, the aerosol generating apparatus uses the optimal alternation frequency to alternate the activation state of the first and second aerosol generators.
In the example where modulating the activation of the first aerosol generator 410 and the second aerosol generator 420 further comprises delaying the activation state of one of the first aerosol generator 410 and second aerosol generator 420 with respect to the other of the first aerosol generator 410 and the second aerosol generator 420, the method may progress to step 3130 where an optimal delay period is determined based on the average inhalation duration of the user. The optimal delay period may be the first delay period in step 3050 or the second delay period in step 3070, for delaying the activation of the first/second aerosol generator with respect to the activation of the second/first aerosol generator. In step 3140, the aerosol generating apparatus uses the optimal delay period to delay the activation of the first/second aerosol generator with respect to the activation of the second/first aerosol generator.
In the example shown in Fig. 28, the method 3000 further comprises optional step 3200 of measuring the inhalation strength of the user over a series of inhalations, for example by way of inhalation sensor 440.
The method may progress to step 3210 where the aerosol generating apparatus adjusts the alternation frequency for alternating the activation states of the first and second aerosol generators based on the average inhalation strength.
In the example where modulating the activation of the first aerosol generator 410 and the second aerosol generator 420 further comprises delaying the activation state of one of the first aerosol generator 410 and second aerosol generator 420 with respect to the other of the first aerosol generator 410 and the second aerosol generator 420, the method may progress to step 3220 where the aerosol generating apparatus adjusts the first or second delay period based on the average inhalation strength.
Fig. 29 shows a schematic representation of the driving scheme for the first aerosol generator 410 and the second aerosol generator 420 according to the methods shown in Fig. 28.
Graphs 3300 and 3400 shows the activation states of the first aerosol generator 410 and the second aerosol generator 420 for two inhalations.
In graph 3300, the aerosol generating apparatus 400 alternates between activating the second aerosol generator 420, as represented by bars 3310, 3330 and 3350, which correspond to portions of the inhalations, and activating only the first aerosol generator 410, as represented by bars 3320, 3340 and 3360, which correspond to the remaining portions of the inhalations.
In graph 3400, the aerosol generating apparatus 400 delays the activation of the first aerosol generator 410 with respect to the activation of the second aerosol generator 420 between the first activation of the second aerosol generator 420 and the first activation of the first aerosol generator 410.
For the first portion of the inhalation 3405 only the second aerosol generator 420 is active, as represented by bar 3410, followed by a period 3406, i.e., the first delay period, where neither of the first aerosol generator 410 and the second aerosol generator 420 are active. For the remainder of the inhalation 3405, the aerosol generating apparatus 400 alternates between activating the second aerosol generator 420, as represented by bar 3430, and activating only the first aerosol generator 410, as represented by bars 3420 and 3440.
Referring to Fig. 30, there is illustrated a method 3500 for controlling an aerosol generating apparatus 400 according to an aspect of the invention.
In the particular method shown in Fig. 30, the method 3500 is a method for alternating between activating only the second aerosol generator 420 and activating only the first aerosol generator 410 over on consecutive of inhalations of a user of the aerosol generating apparatus.
The method begins in step 3510 by activating the second aerosol generator 420, for example, in response to an inhalation of the user. In response to a subsequent inhalation of the user, the method progresses to step 3520 by activating only the first aerosol generator 410.
After step 3520, the method returns to step 3510 and continues to alternate between activating only the second aerosol generator 420 and activating only the first aerosol generator 410 with each inhalation of the user.
Fig. 30 also shows several optional steps for controlling the aerosol generating apparatus 400, and specifically, for controlling the alternation between activating the second aerosol generator 420 and activating the first aerosol generator 410.
The alternation between activating only the second aerosol generator 420 and activating only the first aerosol generator 410 occurs on consecutive inhalations. Put another way, the method switches between steps 3510 and 3520 with each inhalation of the user.
In the example shown in Fig. 30, the method 3500 further comprises optional step 3530 in which it is checked whether an elapsed time since an inhalation last occurred has exceeded a predetermined period.
If the elapsed time since an inhalation last occurred has exceeded the predetermined period, and one inhalation session (or series of inhalations) has stopped and a new inhalation session has effectively begun, the method returns to step 3510 and the second aerosol generator 420 is activated in response to the next inhalation of the user.
If the elapsed time since an inhalation last occurred has not exceeded the predetermined period, the method may then progress to step 3520 where the first aerosol generator 410 is activated in response to the next inhalation of the user.
In the example shown in Fig. 30, the method 3500 further comprises the optional step 3600 of measuring the inhalation duration of the user over a series of inhalations.
In step 3610, the first average inhalation duration for inhalations when the first aerosol generator 410 is active is determined. In step 3620, the second average inhalation duration for inhalations when the second aerosol generator 420 is active is determined.
In step 3630, the first and second average inhalation durations are compared. If the first average inhalation duration is greater than the second average inhalation duration, the method progresses to step 3640 and the first activation period of the first aerosol generator 410 is reduced. The first activation period is a portion of the first average inhalation time. If the second average inhalation duration is greater than the first average inhalation duration, the method progresses to step 3650 and the second activation period of the second aerosol generator is reduced. The second activation period is a portion of the second average inhalation time.
In the example shown in Fig. 30, the method 3500 further comprises optional step 3700 of measuring the inhalation strength of the user over a series of inhalations.
In step 3610, the first average inhalation strength for inhalations when the first aerosol generator 410 is active is determined. In step 3620, the second average inhalation strength for inhalations when the second aerosol generator 420 is active is determined.
In step 3630, the first and second average inhalation strengths are compared. If the first average inhalation strength is greater than the second average inhalation strength, the method progresses to step 3640 and the first activation period of the first aerosol generator 410 is reduced. The first activation period is a portion of the first average inhalation time. If the second average inhalation strength is greater than the first average inhalation strength, the method progresses to step 3650 and the second activation period of the second aerosol generator is reduced. The second activation period is a portion of the second average inhalation time.
Fig. 31 shows a schematic representation of the driving scheme for the first aerosol generator 410 and the second aerosol generator 420 according to the methods shown in Fig. 30.
Graph 3800 shows the activation states of the first aerosol generator 410 and the second aerosol generator 420 for four inhalations.
In graph 3800, the aerosol generating apparatus 400 alternates between activating only the second aerosol generator 420, as represented by bars 3810 and 3830 which correspond to the first and third inhalations, and activating only the first aerosol generator 410, as represented by bars 3820 and 3840 which correspond to the second and fourth inhalations, on consecutive inhalations.
Referring to Fig. 32, there is provided a method 4000 for controlling the aerosol generating apparatus 400 shown in Fig. 11.
The method 4000 begins in step 4010 by obtaining an inhalation strength of the user. The inhalation strength of the user may be obtained, for example, by way of the inhalation sensor 450 shown in Fig. 11. Step 4010 may occur during an initial period of the total inhalation period. The initial period may be of the order of microseconds in duration, for example the first 10µs of the inhalation.
In step 4020, the ratio of the amount of first aerosol to be generated to the amount of second aerosol to be generated for the remainder of the total inhalation period is adjusted according to the obtained inhalation strength.
After the inhalation has finished, the method 4000 may return to step 4010 in preparation for a subsequent inhalation of the user.
Referring to Fig. 33, there is provided an example method 4100 for adjusting the ratio of the amount of first aerosol to the amount of second aerosol generated in response to the inhalation, i.e., for performing step 4020 of the method shown in Fig. 32.
The method 4100 begins in step 4110 by comparing the obtained inhalation strength (for example, the inhalation strength obtained in step 4010 of the method 4000 in Fig. 32) to an inhalation strength threshold. In particular, the obtained inhalation strength is compared to two inhalation strength thresholds, an upper inhalation strength threshold and a lower inhalation strength threshold.
If the obtained inhalation strength is greater than or equal to the upper inhalation strength threshold, the method progresses to step 4120 and the ratio of the first aerosol generated to the second aerosol generated is decreased.
Step 4120 may be performed according to a number of different operations. For example, where the first aerosol generator 431 and the second aerosol generator comprise piezoelectric transducers, the driving parameters of the piezoelectric transducer of the first aerosol generator 431 may be adjusted to reduce the amount of first aerosol generated in response to the inhalation. For example, the first driving power and/or the first driving duty cycle of the piezoelectric transducer of the first aerosol generator 431 may be reduced in order to reduce the amount of first aerosol generated in response to the inhalation.
Correspondingly, the second driving power and/or the second driving duty cycle of the piezoelectric transducer of the second aerosol generator 432 may be increased in order to increase the amount of second aerosol generated in response to the inhalation in order to make up for the reduction in the amount of first aerosol generated.
Alternatively, the activation of the first aerosol generator 431 may be delayed with respect the activation of the second aerosol generator 432 in order to generate first aerosol for a shorter period of time during the inhalation period.
If the obtained inhalation strength is less than or equal to the lower inhalation strength threshold, the method progresses to step 4130 and the ratio of the first aerosol generated to the second aerosol generated is increased.
Step 4130 may be performed according to a number of different operations. For example, where the first aerosol generator 431 and the second aerosol generator comprise piezoelectric transducers, the driving parameters of the piezoelectric transducer of the first aerosol generator 431 may be adjusted to increase the amount of first aerosol generated in response to the inhalation. For example, the first driving power and/or the first driving duty cycle of the piezoelectric transducer of the first aerosol generator 431 may be increased in order to increase the amount of first aerosol generated in response to the inhalation.
Correspondingly, the second driving power and/or the second driving duty cycle of the piezoelectric transducer of the second aerosol generator 432 may be reduced in order to reduce the amount of second aerosol generated in response to the inhalation in order to make up for the increase in the amount of first aerosol generated.
Alternatively, the activation of the second aerosol generator 431 may be delayed with respect the activation of the first aerosol generator 432 in order to generate second aerosol for a shorter period of time during the inhalation period.
Referring to Fig. 34, there is provided a schematic representation of the method 4000 shown in Fig. 32 and the method 4100 shown in Fig. 33.
In particular, Fig. 34 shows a graph 4200 depicting the relative inhalation strengths of three consecutive inhalations of a user of the aerosol generating apparatus 400. Fig. 34 further shows a graph 4300 depicting the ratio of first aerosol to second aerosol generated in response to each inhalation depicted in graph 4200.
The first inhalation 4210 depicted in graph 4200 has an inhalation strength that lies between the upper inhalation strength threshold 4202 and the lower inhalation strength threshold 4204. The first inhalation 4210 is an example of an average strength inhalation.
Correspondingly, the first inhalation 4301 depicted in graph 4300 shows an even ratio between the first aerosol 4310 and the second aerosol 4320 generated in response to the average strength first inhalation 4210 in graph 4200.
The second inhalation 4220 depicted in graph 4200 has an inhalation strength that is less than the lower inhalation strength threshold 4204. The second inhalation 4220 is an example of a weak inhalation.
Correspondingly, the second inhalation 4302 depicted in graph 4300 shows an increase in the ratio of the first aerosol 4330 to the second aerosol 4340 generated in response to the weak second inhalation 4220 in graph 4200.
The third inhalation 4230 depicted in graph 4200 has an inhalation strength that lies above the upper inhalation strength threshold 4202. The third inhalation 4230 is an example of a strong inhalation.
Correspondingly, the third inhalation 4303 depicted in graph 4300 shows a decrease in the ratio of the first aerosol 4350 to the second aerosol 4360 generated in response to the strong third inhalation 4230 in graph 4200.
Fig. 35 shows a method 4500 for driving a piezoelectric transducer 100 of an aerosol generating apparatus according to an aspect of the invention. The method shown in Fig. 35 may be performed for each piezoelectric transducer 100 of the aerosol generating apparatus.
The method 4500 begins in step 4510 by generating a driving signal for driving the piezoelectric transducer 100 to produce aerosol from the liquid aerosol precursor. The driving signal is generated based on driving parameters 4512 including: driving frequency 4514; driving duty cycle 4516; and driving power 4518.
The method 4500 then progresses to step 4520, in which the driving signal is adjusted to change one or more of the driving parameters 4512 so as to produce a target response of the piezoelectric transducer to the driving signal.
The step of adjusting the driving parameters 4520 may include the sub-steps of varying 4522 the driving frequency, the driving duty cycle and/or the driving power and measuring 4524 the response of the piezoelectric transducer to the variation in each driving parameter.
In sub-step 4526, the optimal set of driving parameters, i.e., the optimal driving frequency, the optimal driving duty cycle and the optimal driving power are determined based on the measured response of the piezoelectric transducer to the variation in each driving parameter.
For example, the optimal driving parameters may include the determined resonant frequency of the piezoelectric transducer, the duty cycle that reduces complex frequency components in the piezoelectric transducer's response to the resonant frequency and the driving power that enables both the resonant frequency and duty cycle to be achieved. In a specific example, the optimal driving frequency may be 3MHz, the optimal duty cycle may be between 30% and 40%, and the optimal driving power may be 7.5 Watts.
The method may then progress to step 4530 where the optimal driving parameters determined in step 4526 are used to update the driving parameters 5412 used to generate the driving signal on the next inhalation of the user. These optimal driving parameters then become the last known set of optimal driving parameters 4540 to be used as a starting point for generating the driving signal on the next inhalation of the user.
The method 4500 shown in Fig. 35 is repeated with each inhalation of the user in order to track and update the optimal driving parameters for a piezoelectric transducer over the lifetime of the piezoelectric transducer.
Fig. 36 shows a method 4600 for driving a piezoelectric transducer 100 of an aerosol generating apparatus according to an aspect of the invention. The method shown in Fig. 36 may be performed for each piezoelectric transducer 100 of the aerosol generating apparatus.
The method 4600 begins in step 4610 by generating a driving signal for driving the piezoelectric transducer 100 to produce aerosol from the liquid aerosol precursor. The driving signal is generated based on driving parameters 4612 including: driving frequency 4614; driving duty cycle 4616; and driving power 4618.
The method 4600 then progresses to step 4620, in which it is determined whether the driving signal can be adjusted to change one or more of the driving parameters 4612 within an expected parameter range so as to produce a target response of the piezoelectric transducer to the driving signal.
The step 4620 of determining whether the driving signal can be adjusted to change one or more of the driving parameters 4612 within an expected parameter range may include the sub-steps of varying 4622 the driving frequency within an expected frequency range, the driving duty cycle within an expected duty cycle range and/or the driving power within an expected power range and measuring 4624 the response of the piezoelectric transducer to the variation in each driving parameter within the respect expected range.
In sub-step 4526, the measured response of the piezoelectric transducer to the variation of the driving parameters within the expected driving parameters ranges is compared to the target piezoelectric transducer response.
The method then progresses to step 4630 where it is determined whether the target piezoelectric transducer response can be produced by varying the driving parameters within the expected driving parameters ranges, for example by checking whether a measured response of the piezoelectric transducer from step 4624 matches the target piezoelectric transducer response.
For example, the optimal driving parameters may include the determined resonant frequency of the piezoelectric transducer, the duty cycle that reduces complex frequency components in the piezoelectric transducer's response to the resonant frequency and the driving power that enables both the resonant frequency and duty cycle to be achieved. The expected parameter ranged may be centred on these optimal driving parameters. In a specific example, the optimal driving frequency may be 3MHz and the expected frequency range may be between 2.9MHz and 3.1MHz, the optimal duty cycle may be 35% and the expected duty cycle range may be between 30% and 40%, and the optimal driving power may be 7.5W.
If the target piezoelectric transducer response cannot be produced by varying the driving parameters within the expected driving parameters ranges, the method progresses to step 4632 where it is determined that insufficient liquid aerosol precursor is in contact with the piezoelectric transducer, i.e., a dry hit condition has been reached. In this case, the piezoelectric transducer may be prevented from being driven until sufficient liquid aerosol precursor has been provided.
If the target piezoelectric transducer response can be produced by varying the driving parameters within the expected driving parameters ranges, the method may progress to step 4634 in which the driving parameters are adjusted to achieve the target piezoelectric transducer response.
The last known set of optimal driving parameters 4640 may be used as a starting point for generating the driving signal on the next inhalation of the user.
The method 4600 shown in Fig. 36 is repeated with each inhalation of the user in order to regularly check that sufficient liquid aerosol precursor is in contact with the piezoelectric transducer.
Fig. 37 shows a method 5000 for driving a piezoelectric transducer 100 of an aerosol generating apparatus according to an aspect of the invention. The method shown in Fig. 37 may be performed for each piezoelectric transducer 100 of the aerosol generating apparatus.
The method 5000 begins in step 5010 by generating a driving signal for driving the piezoelectric transducer 100 to produce aerosol from the liquid aerosol precursor. The driving signal is generated based on the set of one or more driving parameters 5012 stored on the cartridge memory unit including: driving frequency 5014; driving duty cycle 5016; and driving power 5018.
The method 5000 then progresses to step 5020, in which the driving signal is adjusted to change one or more of the driving parameters 5012 so as to produce a target response of the piezoelectric transducer to the driving signal.
The step of adjusting the driving parameters 5020 may include the sub-steps of varying 5022 the driving frequency, the driving duty cycle and/or the driving power and measuring 5024 the response of the piezoelectric transducer to the variation in each driving parameter.
In sub-step 5026, the optimal set of driving parameters, i.e., the optimal driving frequency, the optimal driving duty cycle and the optimal driving power are determined based on the measured response of the piezoelectric transducer to the variation in each driving parameter.
For example, the optimal driving parameters may include the determined resonant frequency of the piezoelectric transducer, the duty cycle that reduces complex frequency components in the piezoelectric transducer's response to the resonant frequency and the driving power that enables both the resonant frequency and duty cycle to be achieved. In a specific example, the optimal driving frequency may be 3MHz, the optimal duty cycle may be between 30% and 40%, and the optimal driving power may be 7.5 Watts.
The method may then progress to step 5030 where the optimal driving parameters determined in step 5026 are used to update the driving parameters 5012 stored on the cartridge memory unit to be used to generate the driving signal on the next inhalation of the user.
The method 4500 shown in Fig. 37 may be repeated with each inhalation of the user in order to track and update the optimal driving parameters for a piezoelectric transducer over the lifetime of the piezoelectric transducer.
Fig. 38 shows a method 5100 for controlling an aerosol generating apparatus according to an aspect of the invention.
The method 5100 begins in step 5110 by generating an inhalation count, for example, by counting the number of activations of the aerosol generating unit in response to an inhalation of the user. Alongside step 5110, an aerosol generation efficiency is determined in step 5120 and then, in step 5130, the inhalation count and the aerosol generation efficiency are combined to generate the inhalation metric.
For example, in step 5140 the response of the piezoelectric transducer to the driving signal is measured and then compared, in step 5150, to the expected response of the piezoelectric transducer to a driving signal having the same driving parameters.
For example, for a single inhalation at 50% aerosol generation efficiency, the inhalation metric may be 0.5. In another example, for a series of three inhalations at an aerosol generation efficiency of 100%, the inhalation metric may be 3.
The method may then progress to step 5160 in which the inhalation metric stored on the cartridge memory unit is updated, for example by communication from the electrical circuitry/controller of the aerosol generating apparatus, by way of the device communication unit.
In step 5170, the updated inhalation metric may then be compared to an inhalation metric threshold, which may be stored on the cartridge memory unit and specified at manufacture. If the updated inhalation metric is less than the inhalation metric threshold, the method progresses to step 5180 where it is determined that the replaceable cartridge is not depleted and may continue to be used. If the updated inhalation metric is greater than or equal to the inhalation metric threshold, the method progresses to step 5190, where it is determined that the replaceable cartridge is depleted and requires replacement.
Fig. 39 shows a method 5200 for controlling an aerosol generating apparatus according to an aspect of the invention.
The method 5200 begins in step 5210 by generating a drive count, for example, by counting the number of activations of the aerosol generating unit in response to an inhalation of the user. Alongside step 5210, a drive period is determined in step 5220 and then, in step 5230, the drive count and the drive period are combined to generate the drive metric.
For example, for a single inhalation lasting two seconds, the drive metric may be 2. In another example, for a series of three inhalations lasting one second each, the inhalation metric may be 3.
The method may then progress to step 5240 in which the drive metric stored on the cartridge memory unit is updated, for example by communication from the electrical circuitry/controller of the aerosol generating apparatus, by way of the device communication unit.
In step 5250, the updated drive metric may then be compared to a drive metric threshold, which may be stored on the cartridge memory unit and specified at manufacture. If the updated drive metric is less than the drive metric threshold, the method progresses to step 5260 where it is determined that the piezoelectric transducer is not exhausted and may continue to be used. If the updated drive metric is greater than or equal to the inhalation metric threshold, the method progresses to step 5270, where it is determined that the piezoelectric transducer is exhausted and can no longer be used.
For the avoidance of doubt any of the operations associated with any of the methods described above in relation to Figs. 17 to 39 may be combined or interleaved in any suitable order except where such a combination or ordering is clearly impossible.

REFERENCES

The entirety of the following documents, which are referenced in the present disclosure, are incorporated by reference into the present disclosure:

Kooij, S., Astefanei, A., Corthals, G.L. et al. Size distributions of droplets produced by ultrasonic nebulizers. Sci Rep 9, 6128 (2019). https://doi.org/10.1038/s41598-019-42599-8

Claims

A computer-implemented method for controlling the operation of an aerosol-generating apparatus (1), wherein the aerosol-generating apparatus comprises:
a storage portion (32) for storing an aerosol precursor (6),

a piezoelectric transducer (100) for aerosolizing the aerosol precursor (6), wherein an aerosolizing surface of the piezoelectric transducer is in fluid communication with the storage portion (32),

a communications interface (16) communicatively connected to the piezoelectric transducer (100), and

a processor configured to control one or more operational parameters of the aerosol-generating apparatus (1),
wherein the method comprises:
receiving, at a user device (82) communicatively connected to the communications interface of the aerosol-generating apparatus, data indicative of the one or more operational parameters;

receiving, by a user interface of the user device (82), user input indicative of a desired operating outcome of the aerosol-generating apparatus;

generating instructions, based on the received data and the received user input, for causing the aerosol-generating apparatus to adjust at least one of the one or more operational parameters to achieve the desired operating outcome; and

transmitting the generated instructions to the communications interface of the aerosol-generating apparatus, wherein the processor is configured to execute the generated instructions to adjust the at least one of the one or more operational parameters to achieve the desired operating outcome.
The computer-implemented method according to claim 1, wherein the receiving the data indicative of the one or more operational parameters includes one or more of:
receiving at least some of the data from the aerosol-generating apparatus (1) via the communications interface (16), and

downloading at least some of the data from an application device or application server (84).
The computer-implemented method according to claim 1 or 2, wherein the generated instructions are further suitable for causing the user device (82) to display one or more reminders and/or alerts to the user to prompt the user to adjust their use of the aerosol-generating apparatus (1).
The computer-implemented method according to claim 3, wherein the one or more reminders and/or alerts are based on a set of user preferences provided by the user as part of the received user input.
The computer-implemented method according to any preceding claim, wherein the instructions are further suitable for causing the aerosol-generating apparatus to automatically adjust at least one of the one or more operational parameters in response to a predetermined criterion being satisfied.
The computer-implemented method according to any preceding claim, further comprising:
receiving, at the user device (82), personal usage statistics indicative of a usage pattern of the aerosol-generating apparatus (1) by the user.
The computer-implemented method according to any preceding claim, further comprising:
receiving, at the user device (82), population usage statistics indicative of an average usage pattern of same or similar aerosol-generating apparatuses (1) across a population of users.
The computer-implemented method according to any preceding claim, wherein the one or more operational parameters include one or more driving parameters of a driving signal useable to drive the piezoelectric transducer (100) to aerosolise the aerosol precursor (6).
The computer-implemented method according to any preceding claim, wherein the received data indicative of the one or more operational parameters includes:
data indicative of an amount of aerosol precursor (6) in contact with an aerosolising surface of the piezoelectric transducer (100); and/or

data indicative of a determination of a profile of the aerosol precursor, wherein the determined profile is determined based on a measured response of the piezoelectric transducer (100) to a driving signal.
The computer-implemented method according to any preceding claim, wherein at least some of the received data indicative of the one or more operational parameters is received from a cartridge memory unit installed in a replaceable cartridge of the aerosol generation apparatus (1), the cartridge memory unit being adapted to store one or more of:
a set of one or more operational parameters of the piezoelectric transducer (100), and/or

an inhalation metric associated with the piezoelectric transducer (100).
The computer-implemented method according to any preceding claim, wherein the piezoelectric transducer is a first piezoelectric transducer (100), the aerosol precursor (6) is a first aerosol precursor, and the aerosol-generating apparatus (1) further comprises a second piezoelectric transducer (101) for aerosolizing a second aerosol precursor (7) stored in the storage portion (32) separately from the first aerosol precursor, wherein an aerosolizing surface of the second piezoelectric transducer is in fluid communication with the storage portion, and
wherein the generated instructions cause the aerosol-generating apparatus to:
alternate between activation of only the first piezoelectric transducer (100) and both the first and second piezoelectric transducers (100, 101) over a series of inhalations of a user of the aerosol-generating apparatus (1); and/or

delay an activation of the first piezoelectric transducer (100) with respect to an activation of the second piezoelectric transducer (101) for a first delay period in response to an inhalation of a user of the aerosol-generating apparatus (1); and/or

modulate an activation of the first piezoelectric transducer (100) and the second piezoelectric transducer (101) over a single inhalation period in response to an inhalation of a user of the aerosol generating apparatus (1), wherein modulating the activation of the first and second piezoelectric transducers over the single inhalation period comprises alternating an activation state of the first and second piezoelectric transducers over the single inhalation period; and/or

alternate the activation of the first piezoelectric transducer (100) and the second piezoelectric transducer (101) over a series of inhalations of a user of the aerosol-generating apparatus (1), wherein alternating the activation of the first and second piezoelectric transducers comprises switching between activating the first piezoelectric transducer and activating the second piezoelectric transducer on consecutive inhalations; and/or

adjust a ratio of an amount of first aerosol generated from the first aerosol precursor to an amount of second aerosol generated from the second aerosol precursor based on a strength of a user's inhalation; and/or

adjust a configuration of a first driving circuit configured to drive the first piezoelectric transducer (100) or a second driving circuit configured to drive the second piezoelectric transducer (100, 101) from a driving configuration to a charging configuration in response to a determination that a charging port (9) of the aerosol generating apparatus is connected to an external power source for charging a power supply (2) of the aerosol-generating apparatus (1).
The computer-implemented method according to any preceding claim, wherein the generated instructions cause the aerosol-generating apparatus to:
provide, to the piezoelectric transducer (100), a surface priming signal to drive the piezoelectric transducer so as to expel excess aerosol precursor from a surface of the piezoelectric transducer; and/or

adjust a driving frequency of a driving signal delivered to the piezoelectric transducer (100) to drive the piezoelectric transducer so as to modify one or more parameters of the aerosol generated by the piezoelectric transducer from the aerosol precursor (6).
The computer-implemented method according to any preceding claim, wherein the generated instructions cause the aerosol-generating apparatus to:
provide, to the piezoelectric transducer (100) a first driving signal to drive the piezoelectric transducer at a first driving frequency to generate an aerosol having a first average droplet size, wherein the first driving frequency is a first selected harmonic of the fundamental resonant frequency of the piezoelectric transducer; and

provide, to the piezoelectric transducer (100), a second driving signal to drive the piezoelectric transducer at a second driving frequency to generate an aerosol having a second average droplet size, wherein the second driving frequency is a second selected harmonic of the fundamental resonant frequency.
A computing device comprising a memory and a processor configured to carry out the method of any preceding claim.
A computer-readable medium comprising instructions that, when executed by a processor, cause the processor to carry out the method of any of claims 1 to 13.