CN119084119A - Method and apparatus for determining ash loading level in a fuel particulate filter - Google Patents

Abstract

The present disclosure provides a method for determining a load level of ash in a fuel particulate filter, comprising obtaining a current pressure difference across the fuel particulate filter as exhaust gas flows through the fuel particulate filter based on a determination that a park regeneration operation for the fuel particulate filter has been initiated, obtaining a differential pressure threshold associated with a maximum ash load of the fuel particulate filter, and determining a load level of ash in the fuel particulate filter based on the current pressure difference and the differential pressure threshold.

Description

Method and apparatus for determining ash loading level in a fuel particulate filter

Technical Field

The present disclosure relates generally to the field of vehicles, and more particularly to a method and apparatus for determining a loading level of ash in a fuel particulate filter.

Background

Fuel particulate filters (which may include diesel particulate filters (Diesel Particulate Filter, DPF), gasoline particulate filters (Gasoline Particulate Filter, GPF), etc., depending on the application scenario) are important components in the exhaust system of a vehicle that can capture and store soot (e.g., soot particles resulting from insufficient combustion of fuel) in exhaust gas exiting the combustion chamber of an engine to effectively control and reduce the content of particulate pollutants in the exhaust gas. As trapped soot accumulates during engine operation, the filter screen of the fuel particulate filter may become clogged with the trapped soot, resulting in a gradual deterioration of the filtering capacity. In this case, a regeneration operation may be performed to burn the combustible particles remaining therein by raising the temperature inside the fuel particulate filter. After the regeneration operation, some non-combustible substances (called ash) remain in the fuel particulate filter. When the amount of residual ash reaches a certain value, the residual ash needs to be cleaned in time, otherwise, the exhaust emission can not meet the emission standard, or the fuel intake performance of the vehicle can be affected.

Accordingly, there is a need for a method that can determine the ash loading level in a fuel particulate filter in order to clean the residual ash in a timely manner.

Disclosure of Invention

It is desirable to provide a method and apparatus for determining the loading level of ash in a fuel particulate filter that is capable of determining the loading level of ash based on a current pressure differential obtained after a park regeneration operation is performed on the fuel particulate filter to remove combustible particulates while leaving only ash, and a differential pressure threshold associated with a maximum ash loading to enable timely cleaning of the ash.

According to one aspect of the present disclosure, there is provided a method for determining a load level of ash in a fuel particulate filter, comprising obtaining a current pressure differential across the fuel particulate filter as exhaust gas flows through the fuel particulate filter based on a determination that a park regeneration operation for the fuel particulate filter has been initiated, obtaining a differential pressure threshold associated with a maximum ash load of the fuel particulate filter, and determining a load level of ash in the fuel particulate filter based on the current pressure differential and the differential pressure threshold.

According to yet another aspect of the present disclosure, an apparatus for determining a loading level of ash in a fuel particulate filter is provided that includes a memory and a processor. The processor is coupled to the memory and configured to perform the method according to any of the various embodiments of the disclosure.

According to yet another aspect of the present disclosure, there is provided a computer-readable medium storing a computer program comprising instructions that, when executed by a processor, cause the processor to be configured to perform a method according to any of the various embodiments of the present disclosure.

Drawings

Various embodiments of the claimed subject matter will now be described, by way of example, with reference to the accompanying drawings. The use of the same reference symbols in different drawings indicates identical or similar items.

FIG. 1 illustrates a schematic diagram of an example engine system including a fuel particulate filter, according to one embodiment of the invention.

FIG. 2 illustrates an operational flow diagram of a method for determining a loading level of ash in a fuel particulate filter according to an example embodiment of this disclosure.

Fig. 3 shows a block diagram of an apparatus according to an example embodiment of the present disclosure.

Detailed Description

In the following description, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the present disclosure. One skilled in the relevant art will recognize, however, that the disclosure may be practiced without one or more of the specific details, or with alternative methods, components, etc. In some instances, well-known structures, operations are not shown or described in detail to avoid unnecessarily obscuring the present disclosure.

As discussed in the background section, the fuel particulate filter may capture and collect particulate matter in the exhaust gas through a filter mesh such that the exhaust gas ultimately emitted by the vehicle meets emission standards.

FIG. 1 illustrates a schematic diagram of an example engine system 100 including a fuel particulate filter, according to one embodiment of the invention. As shown in fig. 1, fresh air (which may include a small portion of exhaust gas in the case of including an exhaust gas recirculation system) may enter the combustion chamber 102 via an intake duct, and exhaust gas generated after the combustion reaction in the combustion chamber 102 may flow through an oxidation catalyst, a fuel particulate filter 104, or the like via an exhaust duct to undergo purification treatment, and eventually become clean exhaust gas meeting emission standards, and be discharged to the outside of the vehicle.

It should be noted that the configuration of the engine system 100 as shown in fig. 1 is merely exemplary for illustrating the use of the fuel particulate filter 104 in treating exhaust gas, and that any diesel, gasoline, or other type of engine system configuration is within the scope of the present disclosure.

During engine operation, soot particles trapped from the exhaust gas accumulate in the fuel particulate filter 104. When the amount of particulate matter accumulated in the fuel particulate filter 104 reaches a certain limit, a regeneration operation for the fuel particulate filter may be initiated to reduce the amount of particulate matter accumulated. Regeneration operations may generally be classified into passive regeneration and active regeneration based on whether intervention by an Electronic Control Unit (ECU) is required. Active regeneration may be further classified into driving regeneration and parking regeneration for different execution scenarios (whether executed in a driving scenario or a parking scenario). Wherein, the passive regeneration mainly utilizes nitrogen dioxide (NO 2) generated in the oxidation catalyst to react with the soot particles, thereby reducing the amount of the soot particles, and the process does not need the intervention of an ECU, but can be always executed as long as the temperature requirement is met in the running process of the engine. Both the drive and park regenerations are under the control of the ECU and may be performed by post-injection of in-cylinder fuel, resulting in the exhaust gas generating a significant amount of heat as it passes through the oxidation catalyst, further burning the combustible particles in the fuel particulate filter 104. Parking regeneration generally lasts longer (e.g., more than thirty minutes), has a greater amount of in-cylinder injection, and has a higher reaction temperature than driving regeneration. Thus, by performing the parking regeneration operation, combustible particles in the fuel particulate filter 104 can be burned off to the maximum extent, leaving only non-combustible ash. Among other things, ash may originate primarily from fuel additives, lubricating oil additives, component wear, corrosion, and the like.

These residual ashes cannot be purged by the above regeneration operations (including passive regeneration, drive regeneration, parking regeneration), but require off-line cleaning (for example, typically performed in a maintenance/service station) when the amount of ash reaches a limit. Failure to clean up in time can lead to a series of adverse consequences such as failure of exhaust emissions to meet emission standards, affecting the fuel intake performance of the vehicle, or leading to frequent triggering of regeneration operations by the vehicle to shorten the service life of the fuel particulate filter and reduce fuel economy. Thus, there is a need to accurately estimate the ash loading level in a fuel particulate filter to determine whether cleaning is required.

Currently, there are methods that can be used to estimate the volume of ash in a fuel particulate filter. For example, one method may integrate ash mass flow in a fuel particulate filter over time to calculate ash mass, and then divide the calculated ash mass by fuel ash density to estimate the volume of ash. Another approach may utilize an ash volume estimation model (e.g., a model in the form of a curve or look-up table, etc. established for different modes of operation) to estimate ash volume as a function of engine operating time. However, only a rough estimate of the volume of ash in the fuel particulate filter can be obtained by the above method, and information about the level of ash loading in the fuel particulate filter cannot be provided accurately, nor can it be indicated on the basis of this whether cleaning of ash in the fuel particulate filter is required.

To this end, the present disclosure provides a method for determining a loading level of ash in a fuel particulate filter, which is capable of determining the loading level of ash based on a current pressure difference obtained after a park regeneration operation is performed on the fuel particulate filter to remove combustible particles while leaving only ash, and a pressure difference threshold associated with a maximum ash loading, to enable timely cleaning of the ash. The above-described method of the present disclosure will be described in detail with reference to fig. 2.

FIG. 2 illustrates an operational flow diagram of a method for determining a loading level of ash in a fuel particulate filter according to an example embodiment of this disclosure.

In step S202, it may be determined that the parking regeneration operation has started to be performed. As discussed above, by performing the park regeneration operation, combustible particles in the fuel particulate filter can be burned off to the maximum extent, leaving only non-combustible ash. Thus, by determining that the park regeneration operation has been initiated, the effect of combustible particles (rather than just ash) on accurately determining the loading level of ash in the fuel particulate filter may be eliminated.

In one embodiment, it may be determined that the parking regeneration operation has started to be performed based on (e.g., ECU) receiving an operation mode signal indicating to enter the parking regeneration mode.

Further, as discussed above, the park regeneration mode may be associated with a higher in-cylinder fuel injection amount than other regeneration modes (passive regeneration mode, drive regeneration mode). Accordingly, it is also possible to determine that the execution of the parking regeneration operation has been started based on the recognition that the fuel injection amount of the engine reaches the parking regeneration mode fuel amount threshold. The parking regeneration mode oil amount threshold may be a minimum oil injection amount required for the vehicle to perform a parking regeneration operation, which is obtained based on the statistical data, so that it may be determined that the parking regeneration mode has been entered once the actual oil injection amount reaches the threshold.

Alternatively, as discussed above, the park regeneration mode may be associated with a higher reaction temperature than other regeneration modes (passive regeneration mode, drive regeneration mode). For example, the reaction temperature of the passive regeneration mode is typically between 220 ℃ and 400 ℃, the reaction temperature of the driving regeneration mode is typically between 300 ℃ and 500 ℃, and the reaction temperature of the parking regeneration mode is typically higher than 500 ℃. It should be noted that the above temperature intervals are merely exemplary and do not limit the scope of the present disclosure. In fact, for different vehicle types and working conditions, temperature intervals with different values can be included. Accordingly, it may also be determined that the execution of the park regeneration operation has been started based on the recognition that the temperature of the fuel particulate filter reaches the park regeneration mode temperature threshold. The regeneration mode temperature threshold may be a minimum temperature (e.g., 500 ℃) obtained based on statistical data that is required for the vehicle to perform a park regeneration operation, so that it may be determined that the park regeneration mode has been entered once it is monitored that the temperature of the fuel particulate filter reaches the temperature threshold. The temperature of the fuel particulate filter may refer to a temperature measured by a temperature sensor disposed at an inlet thereof (for example, refer to fig. 1, as indicated by a reference "T"), or a temperature measured or calculated at other locations.

In addition, one or more of the above-described operation mode signal, parking regeneration mode oil amount threshold, and parking regeneration mode temperature threshold may also be used in combination to improve the robustness of the operation for determining that the parking regeneration operation has been started to be performed.

In step S204, a current pressure difference generated across the fuel particulate filter as the exhaust gas flows through the fuel particulate filter may be obtained. The current pressure differential may be obtained if certain detection conditions are met, as discussed in detail in the following paragraphs. In general, obtaining the current pressure difference in response to the detection condition being satisfied enables a stable current pressure difference to be obtained when the park regeneration operation is completed, that is, when the combustible particles in the fuel particulate filter are burned out. Thus, the current pressure differential obtained is largely influenced only by the ash and is exclusive of the influence of combustible particles, thereby facilitating a more accurate determination of the ash loading level.

In one embodiment, the detection condition may include identifying that a duration of performing the park regeneration operation exceeds a predetermined duration threshold. In general, a parking regeneration operation requires a longer duration (e.g., more than 30 minutes) to complete, meaning that during the preceding period of time (e.g., the first 25 minutes or other possible values) in the duration, the combustible particles are not burned out, at which time estimating the gray scale loading level may yield inaccurate results. In other words, the detection condition that the duration of the parking regeneration operation exceeds the predetermined duration threshold helps to determine the ash loading level with substantially only ash remaining in the fuel particulate filter, to improve the accuracy of the results obtained by the method.

In addition, detecting the condition may include identifying that the pressure differential across the fuel particulate filter remains stable for a period of time. The pressure differential may be measured by a differential pressure sensor attached to the fuel particulate filter. In the parking regeneration process, as soot particles are gradually combusted, the condition that a filter screen of the fuel particle filter is blocked is relieved, so that the pressure difference value at two sides of the fuel particle filter is gradually reduced and becomes stable. Accordingly, the pressure differential remaining stable for a period of time may correspondingly indicate that the combustible particles in the fuel particulate filter have been burned out. Similarly to the pressure difference, the trend of the flow resistance of the fuel particulate filter may also be used as the above-described detection condition. The flow resistance represents the ratio between the pressure difference of the fuel particle filter and the flow of exhaust gas through the fuel particle filter. The exhaust gas flow may be measured or calculated by an exhaust gas volume/mass flow meter. Thus, the flow resistance remaining stable over a period of time may also indicate that the combustible particles in the fuel particulate filter have been burned out. In one embodiment, it may be inaccurate to determine whether combustible particles have been burned based solely on the pressure difference, considering the fact that different exhaust gas flows and different soot particle loadings may result in the same pressure difference. Thus, the pressure difference and the flow resistance can be combined to make a judgment. That is, it is determined that the above-described detection condition is satisfied when both the pressure difference value and the flow resistance are simultaneously kept stable for a period of time. Furthermore, in one embodiment, the pressure difference and/or the flow resistance may also be combined with the duration of performing the park regeneration operation discussed above as the above-described detection conditions.

Further, in one embodiment, the parking regeneration operation may be ended in advance in response to the above detection condition being satisfied. As discussed above, the above-described detection conditions may be used to indicate that combustible particles in the fuel particulate filter have been burned out. Thus, ending the parking regeneration operation in advance in this case can avoid unnecessarily exposing the fuel particulate filter to high temperatures, resulting in aging or other adverse effects of the fuel particulate filter.

In one embodiment, obtaining the current pressure difference value at step S204 may include directly taking as the current pressure difference value a differential pressure measurement value measured by a differential pressure sensor attached to the fuel particulate filter when the detection condition is satisfied. In another embodiment, obtaining the current pressure difference value at step S204 may include first obtaining a differential pressure measurement value measured by a differential pressure sensor attached to the fuel particulate filter when the detection condition is satisfied, and then compensating for a differential pressure offset value as the current pressure difference value based on the differential pressure measurement value. The differential pressure offset value may be associated with a reference differential pressure measurement value output by the differential pressure sensor in a vehicle powered-down state. In other words, the differential pressure offset value characterizes a reference differential pressure measurement (which may be non-zero) output by the differential pressure sensor when no exhaust gas is flowing through the fuel particulate filter. Thus, by compensating the differential pressure offset value, the measured value drift which may be caused by the aging, sensitivity, error, and other inherent properties of the differential pressure sensor is taken into account, so that the accuracy of the result obtained by the method can be further improved.

In step S206, a pressure differential threshold associated with a maximum ash loading of the fuel particulate filter may be obtained. In other words, the pressure difference threshold corresponds to the value of the pressure difference in the case where the ash loading in the fuel particulate filter has reached a maximum limit value and cleaning is required. In one embodiment, the differential pressure threshold may be determined based on statistical data obtained through laboratory testing or other approaches regarding the loading of ash in the fuel particulate filter and the value of the corresponding differential pressure. Further, the pressure differential threshold may be affected by the type of vehicle (e.g., in particular, the intake and/or exhaust performance of the engine), the operating conditions of the vehicle (e.g., off-road or on-road vehicle, etc.), the type of fuel particulate filter, and the driving mode, among others.

In step S208, a load level of ash in the fuel particulate filter may be determined based on the current pressure differential and the pressure differential threshold. In particular, the closer the current pressure differential is to the differential pressure threshold, the closer the ash loading in the fuel particulate filter is to the maximum ash limit that can be tolerated, and therefore cleaning may be required in time. In one embodiment, the ratio between the current pressure differential and the differential pressure threshold may be calculated by a division operation such that the ratio is indicative of the ash loading level in the fuel particulate filter. If the current pressure difference value reaches or exceeds the differential pressure threshold value, i.e. the ratio between the current pressure difference value and the differential pressure threshold value is greater than or equal to 1, this means that the ash loading in the fuel particulate filter has reached a maximum limit value, requiring timely cleaning. If the current pressure difference has not reached the differential pressure threshold, i.e. the ratio between the current pressure difference and the differential pressure threshold is less than 1 (e.g. the ratio may also be expressed in percentage form, e.g. 50%, or in any other form such as a fraction or fraction), this means that the ash loading in the fuel particulate filter has not reached a maximum limit value, so that the ash accumulation can be continuously monitored in subsequent operations.

Next, a prompt associated with the determined level of ash in the fuel particulate filter may be further generated for prompting a user of the vehicle (e.g., a driver) whether cleaning of ash in the fuel particulate filter is required. Such prompts may be delivered over an in-vehicle bus (e.g., CAN bus) to a dashboard of the vehicle, or to a user interface device such as an on-board display for presentation to a user of the vehicle. The hint information may be generated and presented in any fixed or adjustable policy. In one embodiment, the prompt may be generated and presented upon determining that the current pressure differential meets or exceeds a differential pressure threshold (by calculating that the ratio between the current pressure differential and the differential pressure threshold is greater than or equal to 1) to inform the user that ash in the fuel particulate filter needs to be cleaned in a timely manner. Alternatively, the ratio between the current pressure difference and the differential pressure threshold may be continuously displayed, for example, in percent form (e.g., 20%, 50%, 100%). Or may continuously display the levels of ash loading corresponding to different ranges of ratios (e.g., one level corresponding to a ratio in the range of 0% -20%, a second level corresponding to a ratio in the range of 20% -50%, etc.). In this case, the user of the vehicle can autonomously judge when the ash in the fuel particulate filter needs to be cleaned based on the above-described prompt information.

In one embodiment, generating and presenting the prompt message may take into account a certain fault tolerance margin to improve the robustness of prompting the user for the operation requiring cleaning. Specifically, a count value may be maintained that corresponds to the number of times the ash loading level in the fuel particulate filter meets or exceeds a hint threshold (e.g., the hint threshold may be an 80% ash loading level, or other possible value). In this case, the count value may be incremented by 1 each time it is determined that the ash loading level in the fuel particulate filter meets or exceeds the hint threshold. And the ash in the fuel particulate filter can be prompted to a user of the vehicle through prompt information only when the count value is greater than or equal to N (wherein N is any positive integer). For example, the value of N may be set to 3 such that the user may be prompted that the current ash loading level has reached 80% when the first determination of the loading level of ash meets or exceeds the cue threshold, may be prompted to the user that the current ash loading level has reached 90% when the second determination of the loading level of ash meets or exceeds the cue threshold, and may be prompted to the user that the current ash loading level has reached 100% when the third determination of the loading level of ash meets or exceeds the cue threshold, thus requiring timely cleaning.

In summary, the strategy of generating and presenting a hint associated with a determined ash loading level in a fuel particulate filter may be flexible and is not limiting to the scope of the present disclosure discussion.

Thus, by the operational flow of the method described in connection with fig. 2, the ash loading level may be determined based on the current pressure differential obtained after performing a park regeneration operation on the fuel particulate filter to remove combustible particulates while leaving only ash, and a differential pressure threshold associated with a maximum ash loading to facilitate timely cleaning of the ash.

Fig. 3 illustrates a block diagram of an apparatus 300 according to an example embodiment of the present disclosure. The apparatus 300 may be used to implement the method for determining the ash loading level in a fuel particulate filter discussed above in connection with fig. 2. In one example, the apparatus 300 may include a control unit of a vehicle, such as the ECU discussed above, or the like.

The example apparatus 300 includes a processor 304 coupled to an internal communication bus 302, the processor 304 configured to execute instructions in a memory 306 to implement the method for determining a loading level of ash in a fuel particulate filter described in detail above. Examples of processor 304 may include a Central Processing Unit (CPU), a microcontroller, and so forth. Memory 306 suitable for tangibly embodying computer program instructions and data includes various forms of memory, e.g., EPROM, EEPROM, and flash memory devices, among others. The apparatus 300 may also include an input interface 308 and an output interface 310. Input interface 308 is used to receive input signals and data, including signals from, for example, differential pressure sensors, temperature sensors, flow meters, etc. discussed above. The output interface 310 is used to send output signals and data, for example, to output the prompt information to the dashboard.

The computer program may include instructions executable by a computer for causing the processor 304 of the apparatus 300 to perform the method of the present disclosure for determining a loading level of ash in a fuel particulate filter. The program may be recorded on any data storage medium including a memory. For example, the program may be implemented in digital electronic circuitry, or in computer hardware, firmware, software, or in combinations of them. The process/method steps described in this disclosure may be performed by a programmable processor executing program instructions to perform methods, steps, operations by operating on input data and generating output.

In addition to what is described herein, various modifications may be made to the disclosed embodiments and implementations of the invention without departing from the scope of the disclosed embodiments and implementations. The specification and examples herein are, accordingly, to be regarded in an illustrative rather than a restrictive sense. The scope of the invention should be measured solely by reference to the claims.

Claims (11)

1. A method for determining a loading level of ash in a fuel particulate filter, comprising:

Obtaining a current pressure difference value generated on both sides of the fuel particulate filter when exhaust gas flows through the fuel particulate filter based on a determination that a parking regeneration operation for the fuel particulate filter has been started to be performed;

obtaining a differential pressure threshold associated with a maximum ash loading of the fuel particulate filter, and

A load level of ash in the fuel particulate filter is determined based on the current pressure differential and the pressure differential threshold.

2. The method according to claim 1, wherein:

Obtaining the current pressure difference is performed in response to the detection condition being met, and

The detection conditions include:

Identifying that the duration of performing the park regeneration operation exceeds a predetermined duration threshold, and/or

It is identified that the pressure differential and/or flow resistance of the fuel particulate filter remains stable for a period of time.

3. The method of claim 1, wherein obtaining the current pressure difference value comprises:

obtaining a differential pressure measurement value measured by a differential pressure sensor attached to the fuel particulate filter when the detection condition is satisfied, and

Compensating a differential pressure offset value based on the differential pressure measurement to obtain the current differential pressure value.

4. A method according to claim 3, wherein the differential pressure offset value is associated with a reference differential pressure measurement output by the differential pressure sensor in a vehicle powered down state.

5. The method of claim 1, wherein determining a loading level of ash in the fuel particulate filter based on the current pressure differential and the pressure differential threshold comprises:

A ratio between the current pressure differential and the differential pressure threshold is calculated, wherein the ratio is indicative of a loading level of ash in the fuel particulate filter.

6. The method of claim 5, further comprising:

A prompt associated with the determined level of ash in the fuel particulate filter is generated for prompting a user of the vehicle whether cleaning of ash in the fuel particulate filter is required.

7. The method of claim 6, wherein generating the hint information comprises:

Maintaining a count value corresponding to a number of times a level of ash loading in the fuel particulate filter meets or exceeds a hint threshold, and

And responding to the count value being greater than or equal to N, prompting the user of the vehicle that ash in the fuel particle filter needs to be cleaned through the prompt information, wherein N is a positive integer.

8. The method of claim 1, further comprising determining that the park regeneration operation for the fuel particulate filter has begun to be performed based on one or more of:

receiving an operation mode signal indicating to enter a parking regeneration mode;

identifying that the fuel injection quantity of the engine reaches the fuel quantity threshold of the parking regeneration mode, and

It is identified that the temperature measured at the fuel particulate filter reaches a park regeneration mode temperature threshold.

9. The method according to claim 2, wherein the parking regeneration operation is ended in advance in response to the detection condition being satisfied.

10. An apparatus for determining a loading level of ash in a fuel particulate filter, comprising:

A memory;

A processor coupled to the memory, the processor configured to perform the method of any of claims 1-9.

11. A computer readable medium storing a computer program comprising instructions which, when executed by a processor, cause the processor to be configured to perform the method of any one of claims 1-9.