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WO2017163650A1 - Dispositif de détection de matière particulaire - Google Patents

Dispositif de détection de matière particulaire Download PDF

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Publication number
WO2017163650A1
WO2017163650A1 PCT/JP2017/004782 JP2017004782W WO2017163650A1 WO 2017163650 A1 WO2017163650 A1 WO 2017163650A1 JP 2017004782 W JP2017004782 W JP 2017004782W WO 2017163650 A1 WO2017163650 A1 WO 2017163650A1
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WIPO (PCT)
Prior art keywords
particulate matter
temperature
output
sensor
unit
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2017/004782
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English (en)
Japanese (ja)
Inventor
小池　和彦
真宏 山本
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Denso Corp
Original Assignee
Denso Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP2016140655A external-priority patent/JP6492035B2/ja
Application filed by Denso Corp filed Critical Denso Corp
Priority to CN201780019188.6A priority Critical patent/CN108885163B/zh
Priority to US16/086,391 priority patent/US10890517B2/en
Priority to DE112017001492.1T priority patent/DE112017001492T5/de
Publication of WO2017163650A1 publication Critical patent/WO2017163650A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
    • G01N15/06—Investigating concentration of particle suspensions
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
    • G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance

Definitions

  • the present disclosure relates to a particulate matter detection device for detecting the number of particulate matter discharged from an internal combustion engine.
  • the particulate matter detection device includes, for example, an electric resistance type sensor element, applies a voltage to the detection electrode portion provided on the surface of the insulating substrate to form an electrostatic field, and collects particulate matter. The change in the resistance value of the detection electrode portion due to the is detected.
  • the particulate matter detection device can estimate the discharge amount of particulate matter from the output of the sensor element.
  • it has been studied to regulate the discharged particulate matter by the number of particles.
  • Patent Document 1 discloses a sensor control device in which a plurality of electric resistance type PM detection units are arranged and the voltage applied to each PM detection unit is adjusted to have different particle size distributions. Yes. This apparatus detects the PM mass from the sensor output of each PM detection unit, and calculates the number of particles from the PM mass and the average particle mass set for each PM detection unit.
  • the particulate matter discharged together with the exhaust gas is a mixture mainly composed of conductive soot (that is, soot), and the particle shape and chemical composition vary greatly depending on engine operating conditions.
  • the particulate matter contains SOF derived from unburned fuel or engine oil (that is, soluble organic fraction), and the amount of SOF changes depending on the engine combustion state. Therefore, the conductivity of the discharged particulate matter varies depending on the amount of SOF, and the conductivity of the particulate matter also varies depending on the exhaust gas temperature around the sensor element, resulting in variations in sensor output.
  • Such a variation in sensor output occurs even when a plurality of PM detection units are formed in the sensor element as in the device of Patent Document 1, and a problem has been found that the detection accuracy is lowered.
  • An object of the present disclosure is to provide a particulate matter detection device that reduces variations in sensor output due to the amount of SOF contained in particulate matter and ambient temperature, and improves the detection accuracy of the number of particles of the particulate matter. Is.
  • One aspect of the present disclosure is a particulate matter detection device that detects particulate matter contained in a gas to be measured.
  • a detector having a pair of electrodes spaced apart from each other on the surface of the insulating substrate exposed to the gas to be measured and a heater having a heater electrode for heating the detector are collected in the detector.
  • a sensor unit that outputs a signal corresponding to the amount of particulate matter to be collected, and a sensor control unit that detects the number of particles of the collected particulate matter based on the sensor output from the sensor unit.
  • the sensor control unit A collection control unit that electrostatically collects particulate matter by applying a voltage between the pair of electrodes of the detection unit; Electric power is supplied to the heater electrode of the heater section, and the SOF in the particulate matter can be volatilized and the soot is heated and held at a first temperature at which the soot does not burn, or the soot is heated and held at a second temperature at which the soot can burn.
  • An output change rate calculating unit that calculates an output change rate that is a ratio of the second output value to A particle number calculation unit for calculating the number of particles using the average particle diameter of the particulate matter estimated from the calculated output change rate and the mass of the particulate matter estimated from the sensor output; ,
  • the particle number calculation unit is in the particulate matter detection device having temperature correction means for correcting the calculated output change rate based on the temperature of the sensor unit at the second output value.
  • Another aspect of the present disclosure is a particulate matter detection device that detects particulate matter contained in a gas to be measured, the number of particles of particulate matter collected based on a sensor output from the sensor unit.
  • a sensor control unit for detecting The sensor control unit A collection control unit that electrostatically collects particulate matter by applying a voltage between the pair of electrodes of the detection unit; Electric power is supplied to the heater electrode of the heater section, and the SOF in the particulate matter can be volatilized and the soot is heated and held at a first temperature at which the soot does not burn, or the soot is heated and held at a second temperature at which the soot can burn.
  • a heating control unit A first output value that is the sensor output at the first temperature and a second output value that is the maximum sensor output when heating from the first temperature to the second temperature are acquired, and the first output value is obtained.
  • An output change rate calculating unit that calculates an output change rate that is a ratio of the second output value to A particle number calculation unit for calculating the number of particles using the average particle diameter of the particulate matter estimated from the calculated output change rate and the mass of the particulate matter estimated from the sensor output; ,
  • the heating control unit is in a particulate matter detection device having a temperature increase control means for controlling a temperature increase rate when heating from the first temperature to the second temperature.
  • the sensor control unit operates the collection control unit to start electrostatic collection of the particulate matter.
  • the heating control unit is operated to heat to the first temperature, the first output value corresponding to the particulate matter from which SOF has been volatilized, and further heated to the second temperature, so that the particulate just before the soot burns.
  • a second output value corresponding to the substance is obtained. Since the output change rate, which is the ratio between the first output value and the second output value, has a correlation with the average particle size of the collected particulate matter, the average particle size can be estimated from the output change rate.
  • the temperature correction unit is provided in the particle number calculation unit as in the above aspect, and correction is performed using the temperature of the sensor unit. By performing this, the average particle diameter can be estimated with high accuracy.
  • the temperature control effect can be reduced by providing a temperature increase control means in the heating control unit and controlling the temperature increase rate from the first temperature to the second temperature. Also in this case, variation in the output change rate can be suppressed and the average particle diameter can be accurately estimated.
  • the number of particles can be calculated using the average particle diameter and the mass of the particulate matter estimated from the sensor output.
  • FIG. 1 is an enlarged view of a main part showing an example of a particulate matter detection sensor constituting a particulate matter detection device in Embodiment 1.
  • FIG. 2 is an overall perspective view showing a configuration example of a sensor element of the particulate matter detection sensor in Embodiment 1.
  • FIG. 3 is a schematic configuration diagram illustrating an overall configuration of an exhaust gas purification apparatus for an internal combustion engine including the particulate matter detection device according to the first embodiment.
  • FIG. 4 is an enlarged view of a main part showing another example of the particulate matter detection sensor in Embodiment 1.
  • FIG. 1 is an enlarged view of a main part showing an example of a particulate matter detection sensor constituting a particulate matter detection device in Embodiment 1.
  • FIG. 2 is an overall perspective view showing a configuration example of a sensor element of the particulate matter detection sensor in Embodiment 1.
  • FIG. 3 is a schematic configuration diagram illustrating an overall configuration of an exhaust gas purification apparatus for an internal combustion engine
  • FIG. 5 is an overall perspective view showing another configuration example of the sensor element of the particulate matter detection sensor in Embodiment 1.
  • FIG. 6 is a flowchart of particulate matter detection processing executed by the sensor control unit of the particulate matter detection device according to the first embodiment.
  • FIG. 7 is a diagram illustrating a change in temperature of the sensor element with respect to an elapsed time from the start of collection of particulate matter in Embodiment 1.
  • FIG. 8 is a diagram illustrating a preferred range of the first temperature when heating the sensor element in Embodiment 1, and compares the relationship between the first temperature and the output change rate when the SOF ratio in the particulate matter is different. Is a diagram showing FIG.
  • FIG. 9 is a diagram illustrating the relationship between the temperature of the sensor element and the output change rate at the second output value in the first embodiment.
  • FIG. 10 is a diagram illustrating the relationship between the output change rate and the average particle diameter before performing temperature correction in the first embodiment.
  • FIG. 11 is a diagram showing the relationship between the output change rate after temperature correction and the average particle diameter in the first embodiment.
  • FIG. 12 is a flowchart of particulate matter detection processing executed by the sensor control unit of the particulate matter detection device in Embodiment 2.
  • FIG. 13 is a flowchart of particulate matter detection processing executed by the sensor control unit of the particulate matter detection device in Embodiment 3.
  • FIG. 14 is a diagram illustrating the relationship between the rate of temperature increase from the first temperature to the second temperature and the output change rate in the third embodiment.
  • FIG. 15 is a diagram illustrating a relationship between an output change rate after temperature increase control and an average particle diameter in the third embodiment.
  • FIG. 16 is a diagram illustrating the relationship between the number of actually measured particles and the estimated number of particles when there is no temperature increase control in Embodiment 3.
  • FIG. 17 is a diagram showing the relationship between the number of actually measured particles and the estimated number of particles when there is a temperature increase control in Embodiment 3.
  • FIG. 18 is a flowchart of particulate matter detection processing executed by the sensor control unit of the particulate matter detection device according to the fourth embodiment.
  • the particulate matter detection device includes a particulate matter detection sensor 1 as a sensor unit that detects particulate matter contained in the gas G to be measured, and a particulate matter detection sensor 1
  • An electronic control unit (hereinafter referred to as ECU) 4 is provided as a sensor control unit for detecting the number of particles of the particulate matter based on the detection signal.
  • the ECU 4 outputs a control signal to the particulate matter detection sensor 1 to control the collection and detection of the particulate matter.
  • the particulate matter detection sensor 1 includes an electric resistance type sensor element 10 and a protective cover 12 covering the outer periphery thereof.
  • the sensor element 10 is detected by being exposed to the gas G to be measured on the front end side (that is, the lower end side in FIG. 1) with the axial direction of the protective cover 12 as the longitudinal direction X (that is, the vertical direction in FIG. 1).
  • Part 2 is provided.
  • the detection unit 2 can be heated by a heater unit 3 built in the sensor element 10.
  • the protective cover 12 has a cylindrical body shape made of a metal material such as stainless steel, and has a plurality of measured gas flow holes 13 and 14 on the side surface and the front end surface.
  • the gas to be measured is introduced into the protective cover 12 from the gas flow hole 13 to be measured on the side surface facing the detection unit 2, and the gas to be measured on the tip surface along the surface of the detection unit 2 A flow of the gas to be measured G toward the flow hole 14 is formed.
  • the gas to be measured G is, for example, combustion exhaust gas discharged from the internal combustion engine E shown in FIG. 3, and the particulate matter (that is, PM) is soot (that is, soot) that is a conductive component and an organic component.
  • the discharge amount of particulate matter and the state of particles, for example, the particle size and chemical composition vary depending on the operating state of the internal combustion engine E.
  • the internal combustion engine E is, for example, a diesel engine, and a diesel particulate filter (hereinafter referred to as a DPF) 5 serving as a particulate matter collecting unit is disposed in an exhaust gas passage E1 through which exhaust gas flows.
  • a DPF diesel particulate filter
  • the particulate matter detection sensor 1 is disposed downstream of the DPF 5 and is fixedly attached to the wall of the exhaust gas passage E1 so that the tip half is located in the exhaust gas passage E1.
  • the particulate matter detection sensor 1 is connected to the ECU 4 and outputs a detection signal corresponding to the amount of PM in the exhaust gas downstream of the DPF 5 to the ECU 4.
  • the sensor element 10 is formed on a rectangular parallelepiped insulating base 11 and the surface of the insulating base 11 in the longitudinal direction X (that is, the right end in the left-right direction in FIG. 2). It has the detection part 2 and the heater part 3 embed
  • the detection unit 2 includes a pair of electrodes 21 and 22 that are printed in a comb shape on one side surface of the insulating substrate 11 (that is, the upper side surface in FIG. 2 and the left side surface in FIG. 1).
  • the comb-like electrodes 21 and 22 are each composed of a plurality of linear electrodes, and linear electrodes having different polarities are alternately arranged in parallel to constitute a plurality of electrode pairs.
  • the electrodes 21 and 22 are respectively connected to linear lead electrodes 21a and 22a extending from the distal end side of the insulating base 11 to the proximal end side (that is, the left end side in FIG. 2).
  • the heater unit 3 includes a heater electrode 31 disposed on the distal end side of the insulating substrate 11 and lead electrodes 31a and 31b connected to the heater electrode 31 and extending to the proximal end side.
  • the insulative base 11 is constituted by a laminated body of a plurality of insulative sheets made of an insulative ceramic material such as alumina, for example.
  • the heater electrode 31 and the lead electrodes 31a and 31b are printed on the surface of the insulating sheet, and the other insulating sheets are overlapped to form a predetermined rectangular parallelepiped shaped body, which is fired. Thereby, the sensor element 10 which incorporates the heater part 3 can be formed.
  • the electrodes 21 and 22 of the detection unit 2, the lead electrodes 21 a and 22 a, the heater electrode 31 of the heater unit 3, and the lead electrodes 31 a and 31 b are made of a conductive material such as a noble metal, for example, and are predetermined electrodes using screen printing or the like. It can be formed into a shape.
  • the heater part 3 is not embedded in the insulating base
  • the heater unit 3 only needs to be configured to be able to heat the detection unit 2, and can be provided separately from the insulating substrate 11, for example.
  • the sensor element 10 of the particulate matter detection sensor 1 is configured to have a detection unit 2 including a pair of electrodes 21 and 22 having a laminated structure on the distal end surface of the insulating substrate 11. Also good.
  • the sensor element 10 is formed, for example, by firing a laminate in which electrode films to be the electrodes 21 or 22 are alternately arranged between a plurality of insulating sheets to be the insulating base 11. At this time, the edge portions of the electrode films to be the electrodes 21 and 22 are alternately exposed on the front end surface of the insulating substrate 11 to form a plurality of electrode pairs composed of linear electrodes having different polarities.
  • the electrode films to be the electrodes 21 or 22 are connected to lead electrodes (not shown), and are connected to each other on the base end side of the insulating substrate 11.
  • the sensor element 10 having the detection unit 2 having a laminated structure has a distal end surface slightly located at the distal end surface where the detection unit 2 is located than the plurality of gas flow holes 13 to be measured opened on the side surface of the protective cover 12. It is arranged to be located on the side.
  • the configuration of the protective cover 12 is the same as that of the example shown in FIG. 1, and the measured gas G flows into the protective cover 12 from the plurality of measured gas flow holes 13 on the side surface, and the measured gas flow on the front end surface. The gas flows toward the hole 14.
  • the flow of the gas to be measured G does not go directly from the gas to be measured flow hole 13 to the detection unit 2, and the flow of the gas to be measured G introduced into the protective cover 12 is in the vicinity of the front end surface of the sensor element 10.
  • the gas flows toward the gas flow hole 14 to be measured on the front end surface.
  • the heater unit 3 (not shown) is provided, and the heater electrode 31 and its lead electrodes 31a and 31b are embedded in the insulating substrate 11 or printed on the surface of the insulating substrate 11. can do.
  • the detection unit 2 may be disposed on one side surface of the distal end side without being formed on the distal end surface. Also in this case, the configuration in which the insulating films to be the electrodes 21 and 22 are arranged between the insulating sheets to be the insulating base 11 and the thickness of the insulating sheet is the distance between the electrodes 21 and 22 is the same.
  • the ECU 4 controls the operation of the detection unit 2 and the heater unit 3 of the particulate matter detection sensor 1 and controls the operating state of the internal combustion engine E.
  • an exhaust gas temperature sensor 51 is attached and fixed to the wall of the exhaust gas passage E1 in the vicinity of the particulate matter detection sensor 1 so that the exhaust gas temperature downstream of the DPF 5 can be detected.
  • An air flow meter 52 is provided to detect the intake flow rate.
  • a rotation speed sensor 53 for detecting the rotation speed of the internal combustion engine E
  • an accelerator pedal sensor 54 for detecting the operation of the accelerator pedal, and other various detection devices are provided. Detection signals from these various detection devices are input to the ECU 4.
  • the ECU4 is a well-known structure provided with the microcomputer 4A, and is connected to various detection apparatuses via the input / output interface I / F.
  • the microcomputer 4A includes a CPU that performs arithmetic processing, a ROM that stores programs and data, and a RAM.
  • the microcomputer 4A periodically executes the program to control each part of the internal combustion engine E including the particulate matter detection sensor 1. To do.
  • the SOF content of the particulate matter discharged into the exhaust gas passage E1 varies.
  • the resistance value of the particulate matter collected by the detection unit 2 changes. Therefore, even if the collected amount is the same with the same particle diameter, the sensor output is different. . Therefore, in this embodiment, the influence of SOF contained in the particulate matter is eliminated, and further, temperature correction is performed, the particle diameter of the particulate matter is estimated, and the number of particles is calculated.
  • the ECU 4 outputs a control signal to the particulate matter detection sensor 1, deposits the particulate matter on the detection unit 2 of the sensor element 10, and collects the particulate matter to be collected based on the signal from the sensor element 10. To detect. Specifically, as shown in FIG. 1, the ECU 4 applies a predetermined voltage between the pair of electrodes 21 and 22 of the detection unit 2 to form an electrostatic field, and generates particulate matter in the gas G to be measured.
  • a collection control unit 41 that electrostatically collects, a heating control unit 42 that supplies power to the heater electrode 31 of the heater unit 3 and heats it to a predetermined temperature, a sensor output V of the sensor element 10, and a particulate matter And a particle number calculation unit 43 that calculates the number N of particles of the collected particulate matter based on the average particle diameter D.
  • the particulate matter detection sensor 1 captures the particulate matter between the pair of electrodes 21 and 22, and detects an electrical characteristic that varies depending on the amount of the particulate matter.
  • the distance between the pair of electrodes 21 and 22 is set, for example, in the range of 5 to 500 ⁇ m. In general, the detection sensitivity increases as the distance decreases.
  • the heater unit 3 can heat the detection unit 2 to a desired temperature, e.g. volatilize SOF contained in the collected particulate matter, and further burn and remove the soot.
  • the first temperature T1 at which SOF can be volatilized is selected in the range of 200 ° C. or more and 400 ° C. or less
  • the second temperature T2 at which the Soot can be burned and removed is selected in the range of 600 ° C. or more and 1000 ° C. or less.
  • the detection unit 2 is controlled to a desired temperature, and the amount of particulate matter is detected stepwise to vary depending on the operating state. This eliminates the influence of SOF and makes it possible to accurately detect the number of particles of particulate matter mainly composed of conductive soot.
  • the temperature T of the sensor element 10 can be estimated using, for example, the correlation between the change in the heater resistance value of the heater unit 3 and the temperature of the heater electrode 31. In general, the larger the heater resistance value, the larger the amount of heat generated by the heater unit 3 and the higher the temperature of the heater electrode 31.
  • a heater circuit is provided between the lead electrodes 31a and 31b by inserting a measurement circuit (not shown).
  • the temperature T of the sensor element 10 is measured using a previously created map or the like.
  • the map or the like can be stored in a ROM that is a storage area of the ECU 4.
  • the temperature T of the sensor element 10 can be detected or estimated by an arbitrary method, and the particulate matter detection sensor 1 can be provided with a temperature sensor or the like that detects the temperature in the vicinity of the detection unit 2.
  • the particle number calculation unit 43 heats the detection unit 2 with the heater unit 3 and is the first sensor output at the first temperature T1 and the maximum sensor output when heating to the second temperature T2. It has the output change rate calculation part 431 which acquires 2nd output value V2 and calculates output change rate V2 / V1 which is those ratios.
  • the output change rate calculation unit 431 includes temperature correction means for correcting the calculated output change rate V2 / V1. This temperature correction means corrects the output change rate V2 / V1 based on the temperature T of the sensor element 10 at the second output value V2, thereby eliminating the influence of the output change rate V2 / V1 due to the temperature. The substance can be detected with higher accuracy.
  • Such a particulate matter detection device can be used for failure diagnosis of the DPF 5 disposed upstream of the particulate matter detection sensor 1.
  • the DPF 5 is normal, the discharged particulate matter is collected by the DPF 5 and hardly discharged downstream.
  • the particulate matter detection sensor 1 on the downstream side measures the number N of the particulate matter to be discharged. Presence / absence can be determined. At that time, the detection accuracy of the particulate matter detection sensor 1 can be improved and the abnormality can be detected quickly by reducing the detection variation due to the influence of the SOF contained in the particulate matter and the temperature effect at the time of detection. .
  • step S ⁇ b> 1 the particulate matter is collected in the detection unit 2 of the particulate matter detection sensor 1. At the start of collection, it is assumed that the particulate matter is burned and removed in advance by a heat treatment described later, and no particulate matter is deposited on the detection unit 2.
  • step S ⁇ b> 1 is processing as the collection control unit 41 of the ECU 4, and a predetermined voltage set in advance is applied between the pair of electrodes 21 and 22 of the sensor element 10 and introduced into the protective cover 12. Particulate matter is deposited on the detector 2.
  • step S2 the sensor output V from the sensor element 10 is taken in, and it is determined whether or not a predetermined output V0 has been reached.
  • the predetermined output V0 which is a reference output
  • the predetermined output V0 is set in advance in correspondence with, for example, the amount of particulate matter deposited that serves as a threshold for failure diagnosis of the DPF 5, and is a particulate matter detection reference. Is the reference output value. If the sensor output V is less than the predetermined output V0, a negative determination is made in step S2, and the process returns to step S1 to continue electrostatic collection and capture of the sensor output V.
  • step S2 when the sensor output V reaches a predetermined output V0, it is determined that the timing for calculating the number of particles of the particulate matter has been reached, the process proceeds to step S3, and the number of particles of the particulate matter is calculated by the subsequent processing.
  • Steps S3 and S5 are processes as the heating control unit 42 of the ECU 4
  • steps S4 and S6 to S12 are processes as the particle number calculation unit 42 of the ECU 4.
  • step S3 electric power is supplied to the heater unit 3 of the sensor element 10 to heat the detection unit 2, and the temperature is raised to the first temperature T1 at which SOF can be volatilized and soot does not burn.
  • the first temperature T1 is selected at a temperature at which an equivalent output change rate V2 / V1 is obtained regardless of the SOF ratio contained in the particulate matter, that is, in a range of 200 ° C. or more and 400 ° C. or less. (For example, 350 ° C.).
  • the heating control unit 42 starts heating after the time point when the predetermined output V0 is reached, and controls the rate of temperature rise so as to converge to a predetermined first temperature T1.
  • the temperature rising rate it is preferable to keep the temperature rising rate constant until the vicinity of the first temperature T1, and then gradually reduce the temperature rising rate so as to converge to the first temperature T1. Details of the relationship between the SOF ratio and the output change rate V2 / V1 will be described later.
  • step S3 As shown in FIG. 7, as the temperature of the detection unit 2 rises due to the operation of the heater unit 3 and converges to the first temperature T1, the sensor output V also draws a similar curve, and the first temperature T1 at the first temperature T1. It converges to one output value V1. This is because the conductivity increases as the SOF volatilizes due to the temperature rise. Therefore, in step S3, a predetermined time required to reach the first temperature T1 is set in advance, and the process proceeds to step S4 after the predetermined time has elapsed.
  • the predetermined time is a time necessary for heating and holding until the first temperature T1 is reached and the SOF is sufficiently volatilized, and can be arbitrarily set (for example, 60 seconds).
  • step S4 the first output value V1 at the first temperature T1 is captured.
  • step S5 the detection unit 2 is further heated by the heater unit 3 and is raised to the second temperature T2.
  • the second temperature T2 is selected within a temperature range in which the soot can be removed by combustion, that is, in the range of 600 ° C. to 1000 ° C. (for example, 800 ° C.). If the second temperature T2 is less than 600 ° C, the combustion of the soot may be insufficient, and if it exceeds 1000 ° C, the heat resistance of the sensor element 10 is affected.
  • the sensor output V As shown in FIG. 7, as the temperature of the detection unit 2 rises from the first temperature T1 and converges to the second temperature T2, the sensor output V also rises in the same way. Thereafter, the sensor output V decreases. This is because the soot does not burn until the sensor output V reaches the second output value V2, which is the maximum output, from the start of heating to the second temperature T2, and the second output value V2 Since the temperature reaches the temperature at which the soot burns, the sensor output V decreases until the soot is burned and removed.
  • the sensor output V further rises from the first output value V1 during the period from the start of heating to the second temperature T2 to the second output value V2.
  • the second temperature T2 that is higher than the first temperature T1. It is presumed that the crystal structure of the captured particulate matter is changed by being heated to change the crystal structure of the graphite having conductivity.
  • step S5 after reaching the second temperature T2 from the first temperature T1, the process proceeds to step S6 after holding for a predetermined time.
  • the predetermined time is, for example, the time necessary for heating and holding until the temperature rises to the second temperature T2 after the sensor output V reaches the second output value V2 and the particulate matter is burned and removed. Can be set arbitrarily.
  • step S6 the second output value V2 that is the maximum output until the temperature rises to the second temperature T2 is captured, and the process proceeds to step S7, where the temperature T of the sensor element 10 at the second output value V2 is detected. Further, in step S8, the output change rate V2 / V1 is calculated from the first output value V1 and the second output value V2.
  • the SOF when the first temperature T1 is changed for the particulate matter having the same average particle diameter (for example, around 55 nm) and different SOF ratios, the SOF is in the range of 200 ° C. to 400 ° C. Regardless of the ratio, the output change rate V2 / V1 is equivalent. That is, when the first temperature T1 is selected in the range of 200 ° C. to 400 ° C., the SOF is sufficiently volatilized in the process of heating to the first temperature T1, and the first output value V1 in which the influence of the SOF is eliminated is obtained. It is done. 8 indicate the results under the conditions where the engine speed is 1654 rpm, the torque is 24 Nm, and the SOF ratio in PM is 7.7 mass%. Moreover, the point of (square) has shown the result on the conditions from which an engine speed is 2117 rpm, a torque is 83 Nm, and a SOF ratio is 1.3 mass%.
  • the output change rate when the SOF ratio is large (that is, the result of ⁇ ) is higher than the output change rate when the SOF ratio is small (that is, the result of ⁇ ). growing.
  • the first temperature T1 is less than 200 ° C.
  • the first output value V1 changes because the volatilization of the SOF becomes insufficient, and the output change rate V2 / V1 increases as the SOF ratio increases. Is done. Further, if the first temperature T1 exceeds 400 ° C., soot combustion may occur.
  • the output change rate V2 / V1 thus obtained has a correlation with the average particle diameter D of the particulate matter, and if the average particle diameter is the same, the first temperature T1 and the second temperature T2 are set to the same condition. In this case, the output change rate V2 / V1 is the same. This is because the particulate matter having a smaller particle diameter is in an amorphous state with lower conductivity, and the crystal structure changes to graphite in the process of being heated to the second temperature T2, thereby improving conductivity. That is, as the average particle diameter D is smaller, the sensor output V before heating tends to be smaller. On the other hand, the sensor output V after heating becomes almost the same value regardless of the particle diameter. The output change rate V2 / V1 is larger.
  • the average particle diameter D of the particulate matter can be estimated from the output change rate V2 / V1 and used for calculation of the number N of particles.
  • the temperature T of the sensor element 10 at the second output value V2 and the output change rate V2 / V1 vary. There was found.
  • FIG. 9 shows the result of repeatedly measuring the output change rate V2 / V1 under several identical operating conditions (that is, the same average particle diameter) in an operation test using an engine bench.
  • the operating conditions were an engine speed of 2117 rpm, a torque of 83 Nm, and the measurement conditions were a first temperature T1 of 350 ° C. and a second temperature T2 of 800 ° C.
  • the temperature T of the sensor element 10 at the second output value V2 varies in the range of 450 ° C. to 500 ° C., and the output change rate V2 / V1 increases as the temperature T increases.
  • the operating conditions of the internal combustion engine E are the same, there is a slight difference in the temperature around the sensor element 10 and the accumulation state of the particulate matter, which affects the start of combustion of the soot. It is estimated that the electrical conductivity is affected by the temperature, and the second output value V2 changes depending on the combustion start temperature. As a result, in FIG.
  • step S9 the output change rate V2 / V1 is corrected based on the temperature T of the sensor element 10.
  • Step S ⁇ b> 9 is a process as a temperature correction unit of the output change rate calculation unit 431.
  • the temperature T of the sensor element 10 at the second output value V2 and the output change rate V2 / V1 have a substantially positive correlation. Each of them can be checked in advance and stored in the ROM of the microcomputer 4A.
  • step S10 the average output particle size D of the particulate matter is estimated using the corrected output change rate V2 / V1, thereby eliminating the influence of the temperature around the sensor element 10 in the detection of the particulate matter. be able to.
  • step S10 the average particle diameter D of the particulate matter is estimated using the corrected output change rate V2 / V1 and the relationship shown by the solid line in FIG.
  • the vertical axis represents the reciprocal of the average particle diameter D (that is, the median diameter), and the experimental results based on EEPS (Engine Exhaust Particle Sizer) Spectrometer are indicated by a solid line, and the range of ⁇ 10% is indicated by a dotted line. Show.
  • EEPS Engine Exhaust Particle Sizer
  • the points in FIGS. 10 and 11 indicate the relationship between the actual average particle diameter D with respect to the output change rate V2 / V1 before correction in step S9 and the output change rate V2 / V1 after correction in step S9. Is shown. As for a plurality of points in FIG. 10, the relationship between the actual average particle diameter D and the output change rate V2 / V1 is seen to be out of the range of the solid line ⁇ 10%, whereas in FIG. As for a plurality of points, almost all are in the range of solid line ⁇ 10%, and it can be seen that the estimation accuracy of the average particle diameter is improved by the correction.
  • the process proceeds to step S11, and the mass M of the particulate matter collected by the detection unit 2 of the sensor element 10 during the collection period is estimated based on the first output value V1.
  • the first output value V1 is a sensor output V based on the particulate matter mainly composed of Soot, and has a positive correlation with the mass M of the particulate matter.
  • the process proceeds to step S12, and the number N of the particulate matter is calculated by the following formulas 1 and 2 using the estimated mass M of the particulate matter and the average particle diameter D.
  • the specific gravity of the particulate matter ie, PM specific gravity
  • the average volume of the particulate matter ie, the PM average volume
  • the particulate substance is regarded as a sphere and is calculated by the above formula 2.
  • step S111 is provided in place of step S11 in FIG. 6, and steps S1 to S10 are the same as those in FIG.
  • step S111 of FIG. 12 instead of the first output value V1 at the first temperature T1, the mass M of the particulate matter is estimated using the sensor output V when step S2 is positively determined.
  • step S2 of FIG. 12 it is determined whether or not the sensor output V has reached a predetermined output V0 set in advance, and the third output value V3 that is the sensor output V at the time when an affirmative determination is made is collected. It has a substantially positive correlation with the mass M of the particulate matter collected by the detection unit 2 of the sensor element 10 during the period. Therefore, this relationship may be examined in advance and stored in the ROM that is a storage area of the ECU 4 to estimate the mass M.
  • the third output value V3 is an output based on the particulate matter before the SOF is removed, but the influence of the SOF on the mass estimation is small. Or you may make it consider an operating condition in the case of mass estimation.
  • step S12 the number N of particulate matter particles can be calculated in the same manner as in the first embodiment using the mass M of the particulate matter calculated in step S111 and the average particle diameter D.
  • the same reference numerals as those used in the above-described embodiments represent the same components as those in the above-described embodiments unless otherwise indicated.
  • the heating control unit 42 includes a temperature increase control unit that controls a temperature increase rate when heating from the first temperature T1 to the second temperature T2.
  • the heating control unit 42 controls the heating rate to be constant until at least the temperature T of the sensor element 10 corresponding to the second output value V2 is exceeded.
  • the particulate matter detection process executed by the ECU 4 that is the sensor control unit is obtained by changing a part of the procedure of the first embodiment shown in FIG. 6. Specifically, the difference is that step S51 is provided in place of step S5 in FIG. 6 and that the temperature acquisition in step S7 and the temperature correction in step S9 are not performed. Steps S1 to S4 are the same as those in FIG.
  • Step S51 of FIG. 13 the sensor element 10 is heated while temperature increase control is performed using the heating control unit.
  • Step S51 is a process as a temperature increase control means. Specifically, a predetermined temperature increase rate ⁇ is set in advance, and from the first temperature T1 to the vicinity of the second temperature T2 as shown in FIG. Then, the temperature is controlled to be constant. Thereafter, the temperature increase rate is gradually decreased to converge to the second temperature T2. As described above, further heating from the state maintained at the first temperature T1 improves the crystallinity of the particulate matter, the sensor output increases, and when the particulate matter combustion start temperature is reached, the second output value V2 is reached. The sensor output drops at a peak.
  • the temperature T corresponding to the second output value V2 should be the same and the output change rate V2 / V1 should be the same.
  • the temperature T varies.
  • FIG. 14 shows a result of measuring the output change rate V2 / V1 by performing an operation test using an engine bench under the same conditions as in FIG. 9, and increases from the first temperature T1 toward the second temperature T2. The relationship with the rate of temperature rise when the temperature was started (for example, 15 ° C./second to 23 ° C./second) was shown.
  • FIG. 14 shows that the output change rate V2 / V1 tends to increase as the heating rate increases. Therefore, the average particle diameter D of the particulate matter can be estimated by obtaining the relationship with the average particle diameter D for each temperature increase rate based on FIG. For example, as indicated by a dotted line in FIG. 14, the output change rate V2 / V1 and the average when the temperature increase rate is controlled to be 18 ° C./second from the first temperature T1 to the second temperature T2.
  • the relationship with the reciprocal of the particle diameter D (that is, the median diameter) is as shown in FIG. That is, when the temperature rising rate is controlled, all the relationships with the actual average particle diameter D are in the range of solid line ⁇ 10%.
  • the temperature increase rate was not controlled, the same variation as shown in FIG. 10 occurred. Thus, it was confirmed that the temperature T in FIG. 7 was stabilized by suppressing the variation in the combustion start temperature of the Soot by controlling the temperature rising rate.
  • step S51 the temperature is increased at a constant temperature increase rate ⁇ until the soot combustion start temperature is sufficiently exceeded, and then the temperature is increased to the second temperature T2 and held for a predetermined time.
  • step S6 the second output value V2 that is the maximum output until the temperature rises to the second temperature T2 is captured.
  • step S8 the output change rate V2 / V1 is calculated from the first output value V1 and the second output value V2.
  • step S7 shown in FIG. 6, that is, the detection of the temperature T of the sensor element 10 at the second output value V2 and the temperature correction 7 of step S9 based on this temperature T are omitted.
  • step 51 by controlling so as to reach a predetermined constant temperature increase rate ⁇ , stable temperature increase is possible based on the temperature increase characteristic known in advance, and the variation in the combustion start temperature of the Soot is reduced.
  • the temperature T at which the second output value V2 is reached becomes substantially constant. Therefore, the output change rate V2 / V1 obtained in step 8 is substantially the same as that obtained when temperature correction is performed.
  • the average particle diameter D can be estimated from the map corresponding to the output change rate V2 / V1 obtained in Step 8 and the temperature increase rate ⁇ .
  • the mass M of the particulate matter is calculated from the first output value V1 in step S11, and then in step S12, the average particle diameter D calculated in steps S10 and S11 and the mass M of the particulate matter are used.
  • the number N of particulate matter particles can be calculated.
  • FIGS. 16 and 17 show the estimated number of particles N, which is the calculated value of step S12, and the number of measured particles, respectively, when the temperature increase rate control is not performed at step 51 and when the temperature increase rate is controlled. It shows the relationship. As indicated by a dotted line in FIG. 16, when the temperature rising rate is not controlled, the relationship between the estimated particle number N and the actually measured particle number is out of the range of the solid line ⁇ 10%. On the other hand, as shown by the dotted line in FIG. 17, when the temperature rising rate is controlled, the relationship between the estimated number of particles N and the number of measured particles is all within the range of solid line ⁇ 10%. Was confirmed.
  • the mass M of the particulate matter can be estimated based on a value other than the first output value V1.
  • the particulate matter detection process executed by the ECU 4 that is the sensor control unit is obtained by changing a part of the procedure of the third embodiment shown in FIG. Specifically, step S111 in place of step S11 in FIG. 13 is different, and steps S1 to S6, S8, and S10 are the same processing as in FIG.
  • the mass M of the particulate matter is estimated using the sensor output V at the time when step S2 is positively determined instead of the first output value V1 at the first temperature T1.
  • step S2 of FIG. 18 it is determined whether or not the sensor output V has reached a predetermined output V0 that is set in advance, and the third output value V3 that is the sensor output V at the time when an affirmative determination is made is used.
  • the third output value V3 has a substantially positive correlation with the mass M of the particulate matter collected by the detection unit 2 of the sensor element 10 during the collection period. It can be stored in a ROM which is a storage area of the ECU 4.
  • step S12 the number N of particulate matter particles can be calculated in the same manner as in the third embodiment using the mass M of the particulate matter calculated in step S111 and the average particle diameter D.
  • a voltage is applied to the detection unit 2 of the particulate matter detection sensor 1 to collect the particulate matter, and the heater unit 3 is used to collect the first temperature T1 and the second temperature.
  • the heater unit 3 is used to collect the first temperature T1 and the second temperature.
  • the particulate matter detection device of the present disclosure including the particulate matter detection sensor 1 and the ECU 4 is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present disclosure.
  • the protective cover 12 that covers the sensor element 10 of the particulate matter detection sensor 1 has a single cylinder structure, but a double cylinder structure including an inner cylinder and an outer cylinder may be used.
  • the arrangement and number of the gas flow holes 13 and 14 to be measured provided in the protective cover 12 can also be set arbitrarily.
  • the shape and material of each part of the sensor element 10 and the protective cover 12 constituting the particulate matter detection sensor 1 can be appropriately changed.
  • the internal combustion engine E is a diesel engine and the DPF 5 serving as a particulate matter collection unit is disposed.
  • a gasoline particulate filter may be disposed using the internal combustion engine E as a gasoline engine.
  • the present invention is not limited to the combustion exhaust gas of the internal combustion engine E, and can be applied to any gas to be measured as long as it includes a particulate matter.

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Abstract

L'invention concerne un dispositif de détection de matière particulaire qui comporte : une unité de capteur (1) qui comprend une unité de détection (2) ayant une paire d'électrodes (21), (22) et une unité d'élément chauffant (3) ayant une électrode d'élément chauffant (31), et qui émet un signal correspondant à une quantité de matière particulaire ; et une unité de commande de capteur (4) qui détecte un nombre de particules (N) de la matière particulaire. L'unité de commande de capteur comprend : une unité de commande de collecte (41) ; une unité de commande de chauffage (42) qui chauffe l'unité de détection à une première température (T1) à laquelle une fraction organique soluble (SOF) se volatilise, et une seconde température (T2) à laquelle la suie brûle ; une unité de calcul de taux de changement de sortie (431) qui calcule un rapport entre une première valeur de sortie (V1) à la première température et une seconde valeur de sortie (V2) qui est la sortie maximale lorsque l'unité de détection est chauffée à la seconde température ; et une unité de calcul de nombre de particules (43) qui calcule le nombre de particules en estimant une taille de particule moyenne (D) de la matière particulaire à partir d'une valeur obtenue en corrigeant ledit rapport sur la base de la température (T) de l'unité de capteur lorsque la seconde valeur de sortie est délivrée.
PCT/JP2017/004782 2016-03-22 2017-02-09 Dispositif de détection de matière particulaire Ceased WO2017163650A1 (fr)

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CN201780019188.6A CN108885163B (zh) 2016-03-22 2017-02-09 颗粒状物质检测装置
US16/086,391 US10890517B2 (en) 2016-03-22 2017-02-09 Particulate matter detection device
DE112017001492.1T DE112017001492T5 (de) 2016-03-22 2017-02-09 Detektionsvorrichtung für partikuläre Materie

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JP2016140655A JP6492035B2 (ja) 2016-03-22 2016-07-15 粒子状物質検出装置
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WO2018110660A1 (fr) * 2016-12-15 2018-06-21 株式会社Ｓｏｋｅｎ Appareil de détection de matière particulaire
CN109085096A (zh) * 2018-08-28 2018-12-25 天津大学 一种获取燃烧过程中碳烟颗粒破碎特性的装置及方法
US20220357261A1 (en) * 2021-05-07 2022-11-10 Honeywell International Inc. Device for detecting liquid content in an aerosol and method of using the same
US11835432B2 (en) 2020-10-26 2023-12-05 Honeywell International Inc. Fluid composition sensor device and method of using the same
US12111257B2 (en) 2020-08-26 2024-10-08 Honeywell International Inc. Fluid composition sensor device and method of using the same
US12181400B2 (en) 2020-02-14 2024-12-31 Honeywell International Inc. Fluid composition sensor device and method of using the same
US12281976B2 (en) 2021-05-13 2025-04-22 Honeywell International Inc. In situ fluid sampling device and method of using the same
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Publication number Priority date Publication date Assignee Title
WO2018110660A1 (fr) * 2016-12-15 2018-06-21 株式会社Ｓｏｋｅｎ Appareil de détection de matière particulaire
CN109085096A (zh) * 2018-08-28 2018-12-25 天津大学 一种获取燃烧过程中碳烟颗粒破碎特性的装置及方法
US12292362B2 (en) 2019-04-26 2025-05-06 Honeywell International Inc. Flow device and associated method and system
US12181400B2 (en) 2020-02-14 2024-12-31 Honeywell International Inc. Fluid composition sensor device and method of using the same
US12111257B2 (en) 2020-08-26 2024-10-08 Honeywell International Inc. Fluid composition sensor device and method of using the same
US11835432B2 (en) 2020-10-26 2023-12-05 Honeywell International Inc. Fluid composition sensor device and method of using the same
US12209941B2 (en) 2020-10-26 2025-01-28 Honeywell International Inc. Fluid composition sensor device and method of using the same
US20220357261A1 (en) * 2021-05-07 2022-11-10 Honeywell International Inc. Device for detecting liquid content in an aerosol and method of using the same
US12281976B2 (en) 2021-05-13 2025-04-22 Honeywell International Inc. In situ fluid sampling device and method of using the same

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