CN116291824A - Method for diagnosing failure of low trapping efficiency of DPF and related hardware - Google Patents

Abstract

An embodiment of the present invention provides a method for diagnosing a low-capture-efficiency fault of a DPF and related hardware, including: obtaining a differential pressure measurement between the upstream pressure of the DPF and the downstream pressure of the DPF collected by the differential pressure sensor of the DPF when the diagnostic condition is satisfied value; determine the current carbon load of the DPF and the amount of exhaust gas currently emitted by the vehicle, and determine the differential pressure range according to the carbon load and the exhaust gas amount; if the measured differential pressure value is not within the differential pressure range, then Determine the diagnostic correction value according to the differential pressure measurement value and the differential pressure range, and correct the basic diagnostic threshold value according to the diagnostic correction value to obtain a modified diagnostic threshold value; if the differential pressure measurement value is less than the duration of the modified diagnostic threshold value If the time is greater than the preset first time threshold, it is determined that the DPF has a low collection efficiency fault. Therefore, it can still be judged whether a failure with low collection efficiency occurs when a large error occurs in the measured value of the DPF differential pressure sensor.

Description

Diagnosis method and related hardware for low capture efficiency fault of DPF

technical field

The invention relates to the technical field of tail gas treatment, in particular to a method for diagnosing the low collection efficiency fault of a DPF and related hardware.

Background technique

A particulate filter (Diesel Particulate Filter, DPF) is a ceramic filter installed in the exhaust system of a diesel engine. The DPF is used to capture particulate emissions. Its working principle is that the exhaust gas of the engine enters the DPF through the pipe, passes through the densely arranged bag filter inside the DPF, and absorbs the soot particles on the filter made of metal fiber felt. When the adsorption amount of particles reaches a certain level, the burner at the end will automatically ignite and burn, and burn the soot particles adsorbed on it into carbon dioxide (CO ₂ ) and then discharge it.

During the working process of the DPF, particulate matter will be deposited in the filter, resulting in an increase in exhaust back pressure. Generally, a DPF differential pressure sensor is used to monitor the pressure difference between the upstream pressure and the downstream pressure of the DPF to identify the amount of particulate matter trapped in the DPF. . When the pressure difference across the DPF reaches a certain limit, it is considered that too many particles are trapped, and a regeneration request will be triggered to oxidize the trapped particles, so that the DPF can regain the ability to trap particles.

Since the DPF differential pressure sensor works in a high temperature environment for a long time, there will be problems such as the aging of the DPF differential pressure sensor and the accumulation of water in the air intake pipe of the DPF differential pressure sensor, which will cause the measured value of the DPF differential pressure sensor to drift and increase the measurement error. Due to the drift of the measured value of the differential pressure sensor, it brings great difficulty to the diagnosis of the low capture efficiency fault of the DPF, which leads to the fault that should have been alarmed due to the large error of the measured differential pressure during the diagnosis of the low capture efficiency of the DPF. It is determined that there is no fault in the situation, or when the DPF is not faulty, a fault is reported by mistake, which affects the safety of driving and increases the cost of after-sales service.

Contents of the invention

The embodiment of the present invention provides a diagnosis method and related hardware for the low collection efficiency fault of the DPF, which is used to solve the inaccurate diagnosis of the low collection efficiency fault of the DPF when the error of the measured value of the DPF differential pressure sensor increases in the prior art The problem.

An embodiment of the present invention provides a method for diagnosing a low-capturing-efficiency fault of a particle trap DPF, including:

When it is determined that the diagnosis condition is met, obtain a differential pressure measurement value between the DPF upstream pressure and the DPF downstream pressure collected by the DPF differential pressure sensor;

Determine the current carbon load of the DPF and the current exhaust gas volume emitted by the vehicle, and determine the differential pressure range according to the carbon load and the exhaust gas volume;

If the differential pressure measurement value is not within the differential pressure range, a diagnostic correction value is determined according to the differential pressure measurement value and the differential pressure range, and the basic diagnostic threshold is corrected according to the diagnostic correction value to obtain a corrected diagnostic threshold ;

If the duration for which the differential pressure measurement value is less than the corrected diagnosis threshold is longer than a preset first time threshold, it is determined that a low collection efficiency fault occurs in the DPF.

Optionally, the method also includes:

If the differential pressure measurement value is within the differential pressure range, and the duration of the differential pressure measurement value being less than the basic diagnosis threshold is longer than a preset second time threshold, it is determined that a low collection efficiency fault occurs in the DPF.

Optionally, the determination of the current carbon load of the DPF includes:

Periodically determine the carbon load sampling value according to the current engine speed and engine torque;

The current carbon load of the DPF is determined according to the periodically determined sampling values of the carbon load.

Optionally, said determining the amount of exhaust gas currently emitted by the vehicle includes:

determining the intake air flow of the engine according to the intake air temperature of the engine and the intake air pressure of the engine;

The exhaust gas amount is determined according to the intake air flow rate of the engine and the fuel consumption amount of the engine.

Optionally, the determining the current carbon load of the DPF and the current exhaust gas volume emitted by the vehicle, and determining the differential pressure range according to the carbon load and the exhaust gas volume include:

Determine the current carbon load of the DPF and the current exhaust gas volume emitted by the vehicle, and filter the current exhaust gas volume emitted by the vehicle through the PT filter algorithm to obtain the filtered exhaust gas volume;

determining the differential pressure range according to the carbon load and the filtered exhaust gas volume;

Wherein, the time constant of the PT filter algorithm is determined according to the length of the air passage between the supercharger of the engine and the vehicle exhaust after-treatment device, and the longer the air passage length is, the larger the time constant is.

Optionally, the diagnostic conditions include at least one of the following:

Within a preset period of time after the electronic control unit ECU of the vehicle is powered on and started;

During the running of the engine of the vehicle, the temperature in the DPF is greater than the preset temperature threshold, and the current exhaust gas volume emitted by the vehicle is greater than the preset exhaust gas volume threshold.

Optionally, the determining the pressure difference range according to the carbon load and the exhaust gas amount specifically includes:

Using the corresponding relationship between the carbon load, the exhaust gas volume and the differential pressure range, determine the current carbon load of the DPF and the corresponding differential pressure range of the exhaust gas volume currently emitted by the vehicle;

Wherein, the corresponding relationship is established in the following manner:

The following tests are carried out several times, wherein the degree of destruction of the target DPF used in each test is different: the target DPF is subjected to a carbon deposition cycle, and when the current carbon load of the target DPF reaches a calibrated carbon load, Carry out a globally uniform test cycle WHTC on the target DPF, measure the pressure difference between the upstream pressure and the downstream pressure of the target DPF corresponding to different exhaust gas volumes during the WHTC process, and determine the pressure difference according to the measured pressure difference value After that, continue to carry out the carbon deposition cycle on the test DPF, until the WHTC is carried out under all the calibrated carbon loads, and the test ends;

The corresponding relationship is established according to the calibrated carbon load, exhaust gas volume and differential pressure range obtained from each test.

Based on the same inventive concept, the embodiment of the present invention also provides a diagnostic device for low collection efficiency fault of DPF, including:

A measurement module, configured to obtain a differential pressure measurement value between the upstream pressure of the DPF and the downstream pressure of the DPF collected by the differential pressure sensor of the DPF when the diagnostic condition is met;

The differential pressure sensor measurement range determination module is used to determine the current carbon load of the DPF and the current exhaust gas volume emitted by the vehicle, and determine the differential pressure range according to the carbon load and the exhaust gas volume;

DPF low collection efficiency fault diagnosis module, used to determine a diagnostic correction value according to the differential pressure measurement value and the differential pressure range if the differential pressure measurement value is not within the differential pressure range, and to correct the diagnostic value according to the differential pressure measurement value The value is corrected to the basic diagnostic threshold to obtain a modified diagnostic threshold; if the duration of the differential pressure measurement value being less than the modified diagnostic threshold is longer than the preset first time threshold, it is determined that a low collection efficiency fault has occurred in the DPF.

Based on the same inventive concept, an embodiment of the present invention also provides an electronic device, including: a processor and a memory for storing instructions executable by the processor;

Wherein, the processor is configured to execute the instructions, so as to implement the method for diagnosing the low collection efficiency fault of the DPF.

Based on the same inventive concept, an embodiment of the present invention also provides a computer-readable storage medium, the computer-readable storage medium stores a computer program, and the computer program is used to realize the low capture efficiency of the DPF fault diagnosis method.

The beneficial effects of the present invention are as follows:

The method for diagnosing the low-capture-efficiency fault of the DPF and related hardware provided by the embodiments of the present invention are determined according to the current carbon load of the DPF and the amount of exhaust gas currently emitted by the vehicle when diagnosing the low-capture efficiency fault of the DPF. The reasonable numerical range of the current differential pressure measurement value. According to the reasonable numerical range, it is judged whether there is an error increase in the differential pressure measurement value collected by the current DPF differential pressure sensor. If the error increases, it is used to diagnose whether low capture occurs. The efficiency diagnostic threshold is corrected, and the corrected diagnostic threshold is used to judge whether the DPF currently has a low collection efficiency fault. Therefore, it can still be judged whether a low-capturing efficiency fault occurs when there is a large error in the measured value of the DPF differential pressure sensor, avoiding the problem of misreporting or missing faults due to incorrect diagnostic conclusions, and ensuring that fuel vehicles (especially fuel-powered vehicles) Diesel-fueled motor vehicles) driving safety and exhaust emission compliance, and also reduce the cost of after-sales service.

Description of drawings

Fig. 1 is one of the flowcharts of the diagnosis method for the low collection efficiency fault of DPF provided by the embodiment of the present invention;

Fig. 2 is an introduction diagram of the nature of the PT filtering algorithm;

Fig. 3 is a flowchart of the establishment process of the corresponding relationship between the calibrated carbon load, exhaust gas volume and differential pressure range provided by the embodiment of the present invention;

Fig. 4 is the second flow chart of the diagnosis method for the low collection efficiency fault of the DPF provided by the embodiment of the present invention;

Fig. 5 is a structural schematic diagram of a diagnostic device for a low collection efficiency fault of a DPF provided by an embodiment of the present invention;

FIG. 6 is a schematic structural diagram of an electronic device provided by an embodiment of the present invention.

Detailed ways

In order to make the above objects, features and advantages of the present invention more comprehensible, the present invention will be further described below in conjunction with the accompanying drawings and embodiments. Example embodiments may, however, be embodied in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art. The same reference numerals denote the same or similar structures in the drawings, and thus their repeated descriptions will be omitted. The words expressing position and direction described in the present invention are all described by taking the accompanying drawings as an example, but changes can also be made according to needs, and all changes are included in the protection scope of the present invention. The drawings of the present invention are only used to illustrate the relative positional relationship and do not represent the true scale.

It should be noted that in the following description, specific details are set forth in order to fully understand the present invention. However, the present invention can be implemented in many other ways than those described here, and those skilled in the art can make similar extensions without departing from the connotation of the present invention. Accordingly, the present invention is not limited to the specific embodiments disclosed below. The subsequent description of the specification is a preferred implementation mode for implementing the application, but the description is for the purpose of illustrating the general principle of the application, and is not intended to limit the scope of the application. The scope of protection of the present application should be defined by the appended claims.

The method for diagnosing the low collection efficiency fault of the DPF provided by the embodiments of the present invention and related hardware will be described in detail below in conjunction with the accompanying drawings.

An embodiment of the present invention provides a method for diagnosing a low-capture-efficiency fault of a DPF, as shown in FIG. 1 , including:

S100. Determine whether a diagnosis condition is met.

If the result of step S100 is yes, execute step S110; if the result of step S100 is no, continue to wait until the result is yes.

S110. Obtain a differential pressure measurement value between the upstream pressure of the DPF and the downstream pressure of the DPF collected by the differential pressure sensor of the DPF.

S120. Determine the current carbon load of the DPF and the current exhaust gas volume emitted by the vehicle, and determine a differential pressure range according to the carbon load and the exhaust gas volume.

In the specific implementation process, the pressure difference range is an interval with an upper limit and a lower limit value, then the pressure difference range is determined according to the carbon load and the exhaust gas amount, that is, according to the carbon load and the The exhaust gas quantity determines the upper limit and the lower limit of the differential pressure range. Specifically, the current carbon load of the DPF and the current exhaust gas volume emitted by the vehicle can be determined by using the pre-established correspondence between the carbon load, the exhaust gas volume, and the differential pressure range (in the form of a function, a curve, or a mapping table, etc.). Corresponding differential pressure range. Generally, when the carbon load is the same, the greater the exhaust gas volume, the larger the upper limit of the differential pressure range; when the exhaust gas volume is the same, the larger the carbon load, the larger the upper limit of the differential pressure range.

S130. Determine whether the measured pressure difference is within the pressure difference range.

If the result of step S130 is negative, step S140 is executed.

S140. Determine a diagnostic correction value according to the differential pressure measurement value and the differential pressure range, and correct a basic diagnostic threshold value according to the diagnostic correction value to obtain a corrected diagnostic threshold value.

As an optional implementation manner, the process of correcting the basic diagnostic threshold according to the diagnostic correction value to obtain the corrected diagnostic threshold may specifically include:

If the differential pressure measurement value is greater than the differential pressure range (that is, the differential pressure measurement value is greater than the upper limit of the differential pressure range), the basic diagnostic threshold is increased by the diagnostic correction value to obtain the Correction of diagnostic thresholds;

If the differential pressure measurement value is less than the differential pressure range (that is, the differential pressure measurement value is less than the lower limit of the differential pressure range), the basic diagnostic threshold is reduced by the diagnostic correction value to obtain the Revise the diagnostic threshold as described above.

In a specific implementation process, the diagnostic correction value may be the difference between the measured differential pressure value and the upper limit or lower limit of the differential pressure range, when the measured differential pressure is greater than the differential pressure In the range, the difference between the differential pressure measurement value and the upper limit of the differential pressure range is used as the diagnostic correction value, and when the differential pressure measurement value is less than the differential pressure range, the differential pressure measurement value and the lower limit of the differential pressure range are used as the diagnosis correction value. Or the first correction relationship between the difference (including the difference with the upper limit and the difference with the lower limit) and the diagnostic correction value can also be established in advance (for example, the first correction relationship is set as a step function, a linear function, etc. ), determining a corresponding diagnostic correction value according to the first correction relationship. Alternatively, a second correction relationship among the pressure difference measurement value, the upper limit value of the pressure difference range, the lower limit value of the pressure difference range, and the diagnostic correction value is established in advance, and the diagnostic correction value is determined according to the second correction relationship; There may be other feasible implementation manners, which will not be limited too much here.

As another optional implementation manner, the process of correcting the basic diagnostic threshold according to the diagnostic correction value to obtain the corrected diagnostic threshold may specifically include:

The modified diagnostic threshold is obtained by multiplying the diagnostic correction value by the basic diagnostic threshold.

In a specific implementation process, if the differential pressure measurement value is greater than the differential pressure range (that is, the differential pressure measurement value is greater than the upper limit of the differential pressure range), the basic diagnostic threshold value is greater than 1 ; If the differential pressure measurement value is less than the differential pressure range (that is, the differential pressure measurement value is less than the lower limit of the differential pressure range), then the basic diagnosis threshold is a value greater than 0 and less than 1. The diagnostic correction value can be established by pre-establishing the difference (including the difference between the measured differential pressure value and the upper limit value of the differential pressure range, and the difference between the measured differential pressure value and the lower limit value of the differential pressure range. difference) and a third correction relationship between the diagnostic correction value (for example, set the third correction relationship as a step function, a linear function, etc.), and determine the corresponding diagnostic correction value according to the third correction relationship. Alternatively, the diagnostic correction value may also be determined according to the fourth correction relationship by pre-establishing a fourth correction relationship between the pressure difference measurement value, the upper limit value of the pressure difference range, the lower limit value of the pressure difference range, and the diagnosis correction value. Diagnosis correction value; it may also be other feasible implementation manners, which will not be limited too much here.

S150. Determine whether the measured pressure difference is smaller than the corrected diagnosis threshold.

If the result of step S150 is yes, execute step S160; if the result of step S150 is no, return to step S100.

S160. Determine whether the duration during which the measured pressure difference value is less than the corrected diagnosis threshold is greater than a preset first time threshold.

If the result of step S160 is yes, execute step S190; if the result of step S160 is no, return to step S100.

S190. Determine that a low collection efficiency fault occurs in the DPF.

After it is determined that the low capture efficiency failure of the DPF occurs, an alarm can be given to the user through the instrument panel of the vehicle, and the event of the low capture efficiency failure of the DPF can be recorded in the total through the On-Board Diagnostics (OBD). Steps such as forming a control module (Power Control Module, PCM), etc., will not be repeated here.

The method for diagnosing the low capture efficiency fault of the DPF provided by the embodiment of the present invention determines the current pressure according to the current carbon load of the DPF and the current amount of exhaust gas emitted by the vehicle when diagnosing the low capture efficiency fault of the DPF. The reasonable value range of the difference measurement value. According to the reasonable value range, it is judged whether there is an error increase in the pressure difference measurement value collected by the current DPF differential pressure sensor. If the error increases, the diagnosis for diagnosing whether low collection efficiency occurs The threshold value is corrected, and the corrected diagnostic threshold value is used to judge whether the DPF currently has a low collection efficiency fault. Therefore, it can still be judged whether a low-capturing efficiency fault occurs when there is a large error in the measured value of the DPF differential pressure sensor, avoiding the problem of misreporting or missing faults due to incorrect diagnostic conclusions, and ensuring that fuel vehicles (especially fuel-powered vehicles) Diesel-fueled motor vehicles) driving safety and exhaust emission compliance, and also reduce the cost of after-sales service.

Further, when the differential pressure measurement value collected by the DPF differential pressure sensor does not have the problem of obvious error increase, the fault of low collection efficiency of the DPF can be diagnosed through the following steps. That is, the method also includes:

If the result of step S130 is yes, execute step S170.

S170. Determine whether the measured pressure difference is smaller than the basic diagnosis threshold.

If the result of the step S170 is yes, execute the step S180; if the result of the step S170 is no, return to the step S100.

S180. Determine whether the duration during which the differential pressure measurement value is less than the basic diagnosis threshold is greater than a preset second time threshold.

If the result of step S180 is yes, execute step S190; if the result of step S180 is no, return to step S100.

In a specific implementation process, the preset first time threshold and the preset second time threshold may be the same value, or may be different values.

Optionally, the diagnostic conditions include at least one of the following:

(1) Within the preset time period after the electronic control unit (Electronic Control Unit, ECU) of the vehicle is powered on and started.

In a specific implementation process, the preset duration may be set to a shorter duration, such as two to three seconds.

(2) During the running of the engine of the vehicle, the temperature in the DPF is greater than the preset temperature threshold, and the current exhaust gas volume emitted by the vehicle is greater than the preset exhaust gas volume threshold.

By performing a DPF low-capture efficiency fault diagnosis when the vehicle ECU is powered on, the low-capture efficiency fault of the particle trap DPF can be found early when the DPF differential pressure sensor has a large measurement error, so that the vehicle can be avoided hazards arise. The DPF can be effectively monitored by performing the fault diagnosis of the low collection efficiency of the DPF when certain conditions are met during the running of the engine.

Optionally, the current carbon load of the DPF can be specifically determined in the following manner:

Periodically determine the carbon load sampling value according to the current engine speed and the current torque of the engine.

The current carbon load of the DPF is determined according to the periodically determined sampling values of the carbon load. Specifically, the current carbon load of the DPF is obtained by accumulating sampling values of each carbon load after the completion of the last regeneration process.

In the specific implementation process, when the engine torque is constant, the greater the engine speed, the greater the corresponding carbon load sampling value; for any sampling time, when the engine speed is constant, the greater the engine torque, the corresponding carbon load The sampling value is indeed larger.

Optionally, the amount of exhaust gas currently emitted by the vehicle may specifically be determined in the following manner:

The intake air flow of the engine is determined according to the intake air temperature of the engine and the intake air pressure of the engine.

The exhaust gas amount is determined according to the intake air flow rate of the engine and the fuel consumption amount of the engine.

In the specific implementation process, the intake air temperature of the engine and the intake air pressure of the engine can be measured by an intake air temperature sensor and an atmospheric pressure sensor (Barometric Pressure Sensor, BPS) respectively, and the fuel consumption of the engine can be obtained by the ECU using the existing It is calculated by the method and will not be repeated here.

In addition, the amount of exhaust gas currently emitted by the vehicle can also be determined in other ways, which will not be described here. Further, no matter what method is used to determine the amount of exhaust gas currently emitted by the vehicle, since the amount of exhaust gas itself is a continuously changing value, and the determination process will cause delays in obtaining this value, in order to avoid the value of the amount of exhaust gas due to interference from external factors In the event of extreme errors in transient mutations, the determined exhaust gas volume can be filtered before determining the differential pressure range based on the carbon load and exhaust gas volume. For example, a PT filter algorithm may be used to filter the exhaust gas volume. Correspondingly, the step S120, determining the current carbon load of the DPF and the current exhaust gas volume emitted by the vehicle, and determining the differential pressure range according to the carbon load and the exhaust gas volume, specifically includes:

Determine the current carbon load of the DPF and the current exhaust gas volume emitted by the vehicle, and filter the current exhaust gas volume emitted by the vehicle through the PT filter algorithm to obtain the filtered exhaust gas volume;

The differential pressure range is determined according to the carbon load and the filtered exhaust gas volume.

In a specific implementation process, the PT filtering algorithm may include a PT ₁ filtering algorithm, a PT ₂ filtering algorithm, a PT _n filtering algorithm, etc. as shown in FIG. 2 . Among them, K _p is the gain (Proportionality constant), T is the time constant (Time constant), ω ₀ is the angular frequency (Angular frequency), D is the damping coefficient (Damping coefficient), n is the degree of order (Degree of order).

Further, the time constant T of the PT filtering algorithm is determined according to the length of the air passage between the supercharger of the engine and the vehicle exhaust after-treatment device.

Furthermore, the longer the airway length is, the larger the time constant T is. In the specific implementation process, the corresponding relationship between the airway length and the time constant T (such as a monotonically increasing linear function, etc.) can be established in advance, and the time constant T of the PT filter algorithm can be determined through the corresponding relationship.

Optionally, it is used to determine the current carbon load of the DPF and the corresponding relationship between the amount of exhaust gas currently emitted by the vehicle and the pressure difference range, which can be specifically established in the following manner:

Multiple tests were performed, each test using a different degree of damage to the target DPF. In the specific implementation process, multiple target DPFs can be prepared, and the damage levels between the target DPFs are different; one target DPF can also be prepared, and the target DPF is destroyed to a preset degree before each test (for example, each time the target DPF is damaged). The target DPF is processed once to a depth of 1 cm, and the area is a depression of 30% of the area of the rear end surface of the DPF), which is not limited here.

As shown in Figure 3, the following steps are performed sequentially each time a test is performed:

S200 , judging whether all the tests have been completed.

If not all tests are completed, proceed to step S210; if all tests are completed, proceed to step S250.

S210, performing a carbon deposition cycle on the target DPF.

S220 , judging whether the test has passed the World Harmoized Transient Cycle (WHTC) under all the calibrated carbon loads. Wherein, the calibration carbon load is a plurality of preset values.

If this test has not passed the global uniform state test cycle under all the calibrated carbon loads, proceed to step S230; if this test has passed the global uniform state test cycle under all the calibrated carbon loads, then end In this test, return to step S200.

S230. Judging whether the current carbon load of the target DPF reaches a calibrated carbon load.

If the current carbon load of the DPF reaches a calibrated carbon load, proceed to step S240; if the current carbon load of the DPF does not reach a calibrated carbon load, continue the carbon deposition cycle of step S210.

S240. Perform WHTC on the target DPF, measure the pressure difference between the upstream pressure and the downstream pressure of the target DPF corresponding to different exhaust gas amounts during the WHTC, and determine the pressure difference range according to the measured pressure difference. Return to step S210 after step S240 is completed.

S250. Establish the corresponding relationship according to the calibrated carbon load, exhaust gas volume and differential pressure range obtained from each test.

The above solution will be specifically described below with a specific example. Wherein, in this example, the lower limit of the differential pressure range is uniformly set to 0. As shown in Figure 4, it specifically includes the following steps:

S300. Determine whether any of the following conditions is met: ① within a preset time period after the ECU of the vehicle is powered on and started; ② during the running of the engine of the vehicle, the temperature in the DPF is greater than the preset temperature threshold, and the amount of exhaust gas currently emitted by the vehicle greater than the preset exhaust gas volume threshold.

If the result of step S300 is yes, execute step S310; if the result of step S300 is no, continue to wait until the result is yes.

S310. Obtain a differential pressure measurement value between the upstream pressure of the DPF and the downstream pressure of the DPF collected by the differential pressure sensor of the DPF.

S320. Determine the current carbon load of the DPF and the current exhaust gas volume emitted by the vehicle, and determine the upper limit of the pressure difference range according to the carbon load and the exhaust gas volume.

S331. Determine whether the measured pressure difference value is less than zero.

If the result of step S331 is yes, execute step S341; if the result of step S331 is no, execute step S332.

S332. Determine whether the measured pressure difference value is greater than the upper limit value of the pressure difference range.

If the result of step S332 is yes, execute step S342; if the result of step S332 is no, execute step S370.

S341. Subtracting 0 from the differential pressure measurement value to determine a diagnostic correction value, and subtracting the diagnostic correction value from the basic diagnostic threshold to obtain a corrected diagnostic threshold. Execute step S350.

S342. Subtracting the upper limit value of the differential pressure range from the measured pressure difference value to determine a diagnostic correction value, and adding the basic diagnostic threshold value to the diagnostic correction value to obtain a corrected diagnostic threshold value. Execute step S350.

S350. Determine whether the measured pressure difference is smaller than the corrected diagnosis threshold.

If the result of step S350 is yes, execute step S360; if the result of step S350 is no, return to step S300.

S360. Determine whether the duration during which the pressure difference measurement value is less than the corrected diagnosis threshold is greater than a preset time threshold.

If the result of step S360 is yes, execute step S390; if the result of step S360 is no, return to step S300.

S370. Determine whether the measured pressure difference is smaller than the basic diagnosis threshold.

If the result of step S370 is yes, execute step S380; if the result of step S370 is no, return to step S300.

S380. Determine whether the duration during which the measured pressure difference is less than the basic diagnosis threshold is greater than a preset time threshold.

If the result of step S380 is yes, execute step S390; if the result of step S380 is no, return to step S300.

S390. Determine that the DPF has a low collection efficiency fault.

Based on the same inventive concept, the embodiment of the present invention also provides a diagnostic device for the low collection efficiency fault of the DPF, as shown in Figure 5, including:

The measurement module M1 is configured to obtain a pressure difference measurement value between the DPF upstream pressure and the DPF downstream pressure collected by the DPF differential pressure sensor when the diagnosis condition is met;

The differential pressure sensor measurement range determination module M2 is used to determine the current carbon load of the DPF and the current exhaust gas volume emitted by the vehicle, and determine the differential pressure range according to the carbon load and the exhaust gas volume;

DPF low collection efficiency fault diagnosis module M3, configured to determine a diagnostic correction value according to the differential pressure measurement and the differential pressure range if the differential pressure measurement is not within the differential pressure range, and according to the diagnostic The correction value corrects the basic diagnostic threshold to obtain a corrected diagnostic threshold; if the duration of the differential pressure measurement value being less than the corrected diagnostic threshold is greater than a preset first time threshold, it is determined that a low collection efficiency fault has occurred in the DPF.

Optionally, the DPF low collection efficiency fault diagnosis module M3 is also used for:

If the differential pressure measurement value is within the differential pressure range, and the duration of the differential pressure measurement value being less than the basic diagnosis threshold is longer than a preset second time threshold, it is determined that a low collection efficiency fault occurs in the DPF.

Optionally, the determination of the current carbon load of the DPF includes:

Periodically determine the carbon load sampling value according to the current engine speed and engine torque;

The current carbon load of the DPF is determined according to the periodically determined sampling values of the carbon load.

Optionally, said determining the amount of exhaust gas currently emitted by the vehicle includes:

determining the intake air flow of the engine according to the intake air temperature of the engine and the intake air pressure of the engine;

The exhaust gas amount is determined according to the intake air flow rate of the engine and the fuel consumption amount of the engine.

Optionally, the determining the current carbon load of the DPF and the current exhaust gas volume emitted by the vehicle, and determining the differential pressure range according to the carbon load and the exhaust gas volume include:

Determine the current carbon load of the DPF and the current exhaust gas volume emitted by the vehicle, and filter the current exhaust gas volume emitted by the vehicle through the PT filter algorithm to obtain the filtered exhaust gas volume;

determining the differential pressure range according to the carbon load and the filtered exhaust gas volume;

Wherein, the time constant of the PT filter algorithm is determined according to the length of the air passage between the supercharger of the engine and the vehicle exhaust after-treatment device, and the longer the air passage length is, the larger the time constant is.

Optionally, the diagnostic conditions include at least one of the following:

Within a preset period of time after the electronic control unit ECU of the vehicle is powered on and started;

During the running of the engine of the vehicle, the temperature in the DPF is greater than the preset temperature threshold, and the current exhaust gas volume emitted by the vehicle is greater than the preset exhaust gas volume threshold.

Optionally, the determining the pressure difference range according to the carbon load and the exhaust gas amount specifically includes:

Using the corresponding relationship between the carbon load, the exhaust gas volume and the differential pressure range, determine the current carbon load of the DPF and the corresponding differential pressure range of the exhaust gas volume currently emitted by the vehicle;

Wherein, the corresponding relationship is established in the following manner:

The following tests are carried out several times, wherein the degree of destruction of the target DPF used in each test is different: the target DPF is subjected to a carbon deposition cycle, and when the current carbon load of the target DPF reaches a calibrated carbon load, Carry out a globally uniform test cycle WHTC on the target DPF, measure the pressure difference between the upstream pressure and the downstream pressure of the target DPF corresponding to different exhaust gas volumes during the WHTC process, and determine the pressure difference according to the measured pressure difference value After that, continue to carry out the carbon deposition cycle on the test DPF, until the WHTC is carried out under all the calibrated carbon loads, and the test ends;

The corresponding relationship is established according to the calibrated carbon load, exhaust gas volume and differential pressure range obtained from each test.

It should be understood that the above-described embodiment of the diagnosis device for the low capture efficiency fault of the DPF is only illustrative. For example, the division of the modules is only a logical function division, and there may be other in actual implementation. The manner in which multiple modules or components can be combined or can be integrated into another system, or some features can be omitted, or not implemented, for example. Each functional module in the embodiment may be integrated into one processing module, or each module may exist separately physically, or two or more modules may be integrated into one module. The above-mentioned integrated modules can be implemented in the form of hardware or in the form of software function modules. If the integrated modules are realized in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium.

Since the problem-solving principle of the diagnostic device for the low collection efficiency fault of the DPF is basically the same as the diagnosis method for the low collection efficiency fault of the DPF, the diagnostic device for the low collection efficiency fault of the DPF For the implementation, reference may be made to the implementation of the method for diagnosing the low collection efficiency fault of the DPF, which will not be repeated here.

Based on the same inventive concept, an embodiment of the present invention also provides an electronic device, as shown in FIG. 6 , including: a processor 1100 and a memory 1200 for storing instructions executable by the processor 1100; wherein, the processor 1100 is configured to execute the instructions, so as to realize the reliability testing method of the vehicle exhaust after-treatment device.

In the specific implementation process, the device may have relatively large differences due to different configurations or performances, and may include one or more processors 1100, memories 1200, computer-readable storage media 1300, and the memory 1200 and/or computer The readable storage medium 1300 includes one or more application programs 1310 or data 1320 . The memory 1200 and/or the computer-readable storage medium 1300 may also include one or more operating systems 1330, such as Windows, Mac OS, Linux, IOS, Android, Unix, FreeBSD, etc. Wherein, the memory 1200 and the computer-readable storage medium 1300 may be temporary storage or persistent storage. The application program 1310 may include one or more modules (not shown in FIG. 6 ), and each module may include a series of instruction operations. Furthermore, the processor 1100 may be configured to communicate with the computer-readable storage medium 1300, and execute a series of instruction operations in the storage medium 1300 on the device. The device may also include one or more power supplies (not shown in FIG. 6 ); one or more network interfaces 1400, the network interface 1400 including a wired network interface 1410 and/or a wireless network interface 1420; one or more Input and output interface 1430 .

Based on the same inventive concept, an embodiment of the present invention also provides a computer-readable storage medium, the computer-readable storage medium stores a computer program, and the computer program is used to realize the reliable operation of the vehicle exhaust after-treatment device. sexual testing method.

The method for diagnosing the low-capture-efficiency fault of the DPF and related hardware provided by the embodiments of the present invention are determined according to the current carbon load of the DPF and the amount of exhaust gas currently emitted by the vehicle when diagnosing the low-capture efficiency fault of the DPF. The reasonable numerical range of the current differential pressure measurement value. According to the reasonable numerical range, it is judged whether there is an error increase in the differential pressure measurement value collected by the current DPF differential pressure sensor. If the error increases, it is used to diagnose whether low capture occurs. The efficiency diagnostic threshold is corrected, and the corrected diagnostic threshold is used to judge whether the DPF currently has a low collection efficiency fault. Therefore, it can still be judged whether a low-capturing efficiency fault occurs when there is a large error in the measured value of the DPF differential pressure sensor, avoiding the problem of misreporting or missing faults due to incorrect diagnostic conclusions, and ensuring that fuel vehicles (especially fuel-powered vehicles) Diesel-fueled motor vehicles) driving safety and exhaust emission compliance, and also reduce the cost of after-sales service.

Those skilled in the art should understand that the embodiments of the present application may be provided as methods, systems, or computer program products. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to the present application. It should be understood that each procedure and/or block in the flowchart and/or block diagram, and a combination of procedures and/or blocks in the flowchart and/or block diagram can be realized by computer program instructions. These computer program instructions may be provided to a general purpose computer, special purpose computer, embedded processor, or processor of other programmable data processing equipment to produce a machine such that the instructions executed by the processor of the computer or other programmable data processing equipment produce a An apparatus for realizing the functions specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing apparatus to operate in a specific manner, such that the instructions stored in the computer-readable memory produce an article of manufacture comprising instruction means, the instructions The device realizes the function specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions can also be loaded onto a computer or other programmable data processing device, causing a series of operational steps to be performed on the computer or other programmable device to produce a computer-implemented process, thereby The instructions provide steps for implementing the functions specified in the flow chart or blocks of the flowchart and/or the block or blocks of the block diagrams.

Obviously, those skilled in the art can make various changes and modifications to the application without departing from the spirit and scope of the application. In this way, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application is also intended to include these modifications and variations.

Claims (10)

1. A method of diagnosing a failure in low trapping efficiency of a particle trap DPF, comprising:

when the diagnosis condition is determined to be met, acquiring a differential pressure measured value between DPF upstream pressure and DPF downstream pressure acquired by a DPF differential pressure sensor;

determining the current carbon loading of the DPF and the current exhaust gas amount discharged by the vehicle, and determining a differential pressure range according to the carbon loading and the exhaust gas amount;

if the differential pressure measured value is not in the differential pressure range, determining a diagnosis correction value according to the differential pressure measured value and the differential pressure range, and correcting a basic diagnosis threshold value according to the diagnosis correction value to obtain a corrected diagnosis threshold value;

and if the duration that the pressure difference measured value is smaller than the corrected diagnosis threshold value is larger than a preset first time threshold value, determining that the DPF has low trapping efficiency fault.

2. The method of claim 1, wherein the method further comprises:

and if the differential pressure measured value is in the differential pressure range and the duration that the differential pressure measured value is smaller than the basic diagnosis threshold value is larger than a preset second time threshold value, determining that the DPF has low trapping efficiency fault.

3. The method of claim 1, wherein said determining the current carbon loading of the DPF comprises:

periodically determining a carbon load sampling value according to the current rotating speed of the engine and the current torque of the engine;

and determining the current carbon loading of the DPF according to each periodically determined carbon loading sampling value.

4. The method of claim 1, wherein the determining the amount of exhaust currently being emitted by the vehicle comprises:

determining the air inlet flow of an engine according to the air inlet temperature of the engine and the air inlet pressure of the engine;

and determining the exhaust gas amount according to the air inlet flow of the engine and the oil consumption amount of the engine.

5. The method of claim 1 or 4, wherein said determining the current carbon loading of the DPF and the current amount of exhaust gas being emitted by the vehicle, determining a differential pressure range based on said carbon loading and said amount of exhaust gas, comprises:

determining the current carbon loading of the DPF and the current exhaust gas amount of the vehicle, and filtering the current exhaust gas amount of the vehicle through a PT filtering algorithm to obtain the filtered exhaust gas amount;

determining a differential pressure range based on the carbon loading and the amount of filtered exhaust gas;

the time constant of the PT filtering algorithm is determined according to the length of an air passage between a supercharger of the engine and a vehicle tail gas aftertreatment device, and the longer the length of the air passage is, the larger the time constant is.

6. The method of claim 1, wherein the diagnostic conditions include at least one of:

the method comprises the steps that an electronic control unit ECU of the vehicle is powered on and started for a preset time period;

during operation of the engine of the vehicle, the temperature within the DPF is greater than a preset temperature threshold and the amount of exhaust currently emitted by the vehicle is greater than a preset exhaust amount threshold.

7. The method according to claim 1, wherein said determining a differential pressure range from said carbon loading and said amount of exhaust gas, in particular comprises:

determining a differential pressure range corresponding to the current carbon loading of the DPF and the current exhaust gas amount of the vehicle by utilizing the corresponding relation among the carbon loading, the exhaust gas amount and the differential pressure range;

the corresponding relation is established in the following way:

the following tests were performed, wherein the degree of damage treatment of the subject DPF used for each test was different: performing carbon deposition circulation on the target DPF, performing global uniform state test circulation WHTC on the target DPF when the current carbon loading of the target DPF reaches a calibrated carbon loading, measuring differential pressure values between upstream pressure and downstream pressure of the target DPF corresponding to different exhaust gas quantities in the WHTC process, and determining a differential pressure range according to the measured differential pressure values; continuing to perform carbon deposition circulation on the test DPF until the test is finished after WHTC is performed under all the calibrated carbon loading;

and establishing the corresponding relation according to the calibrated carbon loading, the exhaust gas amount and the differential pressure range obtained by each test.

8. A diagnostic device for a failure in low trapping efficiency of a DPF, comprising:

the measuring module is used for acquiring a differential pressure measured value between the DPF upstream pressure and the DPF downstream pressure acquired by the DPF differential pressure sensor when the diagnosis condition is met;

the measuring range determining module of the differential pressure sensor is used for determining the current carbon loading of the DPF and the current exhaust gas amount discharged by the vehicle, and determining the differential pressure range according to the carbon loading and the exhaust gas amount;

the DPF low-trapping efficiency fault diagnosis module is used for determining a diagnosis correction value according to the differential pressure measured value and the differential pressure range if the differential pressure measured value is not in the differential pressure range, and correcting a basic diagnosis threshold value according to the diagnosis correction value to obtain a corrected diagnosis threshold value; and if the duration that the pressure difference measured value is smaller than the corrected diagnosis threshold value is larger than a preset first time threshold value, determining that the DPF has low trapping efficiency fault.

9. An electronic device, comprising: a processor and a memory for storing instructions executable by the processor;

wherein the processor is configured to execute the instructions to implement a method of diagnosing a low trapping efficiency failure of a DPF as recited in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that the computer-readable storage medium stores a computer program for implementing a method of diagnosing a failure in low trapping efficiency of a DPF as set forth in any one of claims 1 to 7.

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