Diagnostic method for low capture efficiency failure of DPF and related hardware

Abstract

An embodiment of the present invention provides a diagnostic method and related hardware for a DPF low trapping efficiency fault. The method includes: obtaining a pressure differential measurement between the DPF upstream pressure and the DPF downstream pressure, as collected by a DPF differential pressure sensor, upon determining that diagnostic conditions are met; determining the current carbon load of the DPF and the current exhaust volume emitted by the vehicle, and determining a pressure differential range based on the carbon load and exhaust volume; determining a diagnostic correction value based on the pressure differential measurement and the pressure differential range if the pressure differential measurement is not within the pressure differential range, and correcting a basic diagnostic threshold based on the diagnostic correction value to obtain a corrected diagnostic threshold; and determining a DPF low trapping efficiency fault if the duration for which the pressure differential measurement is less than the corrected diagnostic threshold exceeds a preset first time threshold. This method enables the determination of a low trapping efficiency fault even when the DPF differential pressure sensor's measurement value exhibits significant errors.

Description

Technical Field

[0001] The present invention relates to the technical field of exhaust gas treatment, and in particular to a method for diagnosing a low capture efficiency fault of a DPF and related hardware. Background Art

[0002] A Diesel Particulate Filter (DPF) is a ceramic filter installed in a diesel engine's exhaust system. It captures particulate matter. Its operating principle is that engine exhaust enters the DPF through a pipeline. It then passes through the densely packed bag filters within the DPF, where soot particles are adsorbed onto a metal fiber felt filter. When the adsorption of particles reaches a certain level, a burner at the rear end automatically ignites, converting the adsorbed soot particles into carbon dioxide (CO2) for expulsion.

[0003] During DPF operation, particulate matter accumulates within the filter, increasing exhaust backpressure. A DPF differential pressure sensor is typically used to monitor the pressure difference between the upstream and downstream pressures of the DPF to identify the amount of particulate matter trapped within the DPF. When the pressure difference across the DPF reaches a certain limit, it is considered excessive particle capture, triggering a regeneration request to oxidize the trapped particles and restore the DPF's ability to capture particles.

[0004] Due to the DPF differential pressure sensor operating in a high-temperature environment for a long time, it may age and accumulate water in the DPF differential pressure sensor's intake pipe, causing the sensor's measured value to drift and increasing measurement errors. This drift in the differential pressure sensor's measured value greatly complicates the diagnosis of low DPF capture efficiency. When diagnosing low DPF capture efficiency, the large error in the measured differential pressure may result in the DPF misdiagnosing a fault when it should be faulty, or misdiagnosing a fault when it is not, affecting driving safety and increasing after-sales service costs. Summary of the Invention

[0005] The embodiment of the present invention provides a method for diagnosing a DPF low capture efficiency fault and related hardware, so as to solve the problem in the prior art that when the measurement error of the DPF differential pressure sensor increases, the DPF low capture efficiency fault diagnosis may be inaccurate.

[0006] An embodiment of the present invention provides a method for diagnosing a low capture efficiency fault of a particulate filter (DPF), comprising:

[0007] When it is determined that the diagnostic condition is met, a pressure difference measurement value between a DPF upstream pressure and a DPF downstream pressure collected by a DPF pressure difference sensor is obtained;

[0008] Determining a current carbon load of the DPF and a current amount of exhaust gas emitted by the vehicle, and determining a pressure differential range based on the carbon load and the exhaust gas amount;

[0009] If the pressure difference measurement value is not within the pressure difference range, determining a diagnosis correction value according to the pressure difference measurement value and the pressure difference range, and correcting the basic diagnosis threshold according to the diagnosis correction value to obtain a corrected diagnosis threshold;

[0010] If the duration of the pressure difference measurement value being less than the modified diagnosis threshold value is greater than a preset first time threshold value, it is determined that a low trapping efficiency fault occurs in the DPF.

[0011] Optionally, the method further includes:

[0012] If the pressure difference measurement value is within the pressure difference range, and the duration of the pressure difference measurement value being less than the basic diagnosis threshold value is greater than a preset second time threshold, it is determined that a low trapping efficiency fault occurs in the DPF.

[0013] Optionally, determining the current carbon load of the DPF includes:

[0014] Periodically determining a carbon load sampling value based on a current engine speed and a current engine torque;

[0015] The current carbon load of the DPF is determined according to each of the carbon load sampling values ​​determined periodically.

[0016] Optionally, determining the amount of exhaust gas currently emitted by the vehicle includes:

[0017] determining an intake air flow rate of the engine based on an intake air temperature of the engine and an intake air pressure of the engine;

[0018] The exhaust gas amount is determined according to an intake air flow rate of the engine and a fuel consumption amount of the engine.

[0019] Optionally, determining a current carbon load of the DPF and a current amount of exhaust gas emitted by the vehicle, and determining a pressure difference range according to the carbon load and the exhaust gas amount, includes:

[0020] Determine the current carbon load of the DPF and the current exhaust gas volume emitted by the vehicle, filter the current exhaust gas volume emitted by the vehicle through the PT filtering algorithm, and obtain the filtered exhaust gas volume;

[0021] determining a differential pressure range based on the carbon loading and the filtered exhaust gas volume;

[0022] The time constant of the PT filtering algorithm is determined according to the length of the airway between the supercharger of the engine and the vehicle exhaust after-treatment device, and the longer the airway length is, the larger the time constant is.

[0023] Optionally, the diagnostic condition includes at least one of the following:

[0024] Within the preset time after the vehicle's electronic control unit ECU is powered on;

[0025] During engine operation of the vehicle, the temperature inside the DPF is greater than a preset temperature threshold, and the amount of exhaust gas currently emitted by the vehicle is greater than a preset exhaust gas amount threshold.

[0026] Optionally, determining the pressure difference range according to the carbon load and the exhaust gas volume specifically includes:

[0027] Using the corresponding relationship between carbon load, exhaust gas volume and pressure differential range, determine the pressure differential range corresponding to the current carbon load of the DPF and the current exhaust gas volume emitted by the vehicle;

[0028] The corresponding relationship is established in the following manner:

[0029] The following test is performed multiple times, wherein the target DPF used in each test has a different degree of damage treatment: the target DPF is subjected to a carbon deposition cycle, and when the current carbon loading of the target DPF reaches a calibrated carbon loading, the target DPF is subjected to a World Harmonized Temperature Test (WHTC) cycle, during which the pressure differential between the upstream and downstream pressures of the target DPF corresponding to different exhaust gas volumes is measured, and a pressure differential range is determined based on the measured pressure differential values; the target DPF is then subjected to carbon deposition cycles again until the WHTC cycle is performed at all calibrated carbon loadings, and the test is terminated.

[0030] The corresponding relationship is established based on the calibrated carbon load, exhaust gas volume and pressure difference range obtained from each test.

[0031] Based on the same inventive concept, an embodiment of the present invention further provides a diagnostic device for a low capture efficiency fault of a DPF, comprising:

[0032] a measuring module, configured to obtain a pressure difference measurement value between a DPF upstream pressure and a DPF downstream pressure acquired by a DPF pressure difference sensor when a diagnostic condition is determined to be met;

[0033] A 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 based on the carbon load and the exhaust gas volume;

[0034] The DPF low capture efficiency fault diagnosis module is configured to determine a diagnostic correction value based on the pressure difference measurement value and the pressure difference range if the pressure difference measurement value is not within the pressure difference range, and to correct the basic diagnostic threshold value based on the diagnostic correction value to obtain a corrected diagnostic threshold value; and to determine that a DPF low capture efficiency fault occurs if the duration for which the pressure difference measurement value is less than the corrected diagnostic threshold value is greater than a preset first time threshold.

[0035] Based on the same inventive concept, an embodiment of the present invention further provides an electronic device, comprising: a processor and a memory for storing instructions executable by the processor;

[0036] The processor is configured to execute the instructions to implement the method for diagnosing a low capture efficiency fault of a DPF.

[0037] Based on the same inventive concept, an embodiment of the present invention further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and the computer program is used to implement the method for diagnosing a low capture efficiency fault of a DPF.

[0038] The beneficial effects of the present invention are as follows:

[0039] The method and related hardware for diagnosing a DPF low capture efficiency fault, provided in an embodiment of the present invention, determine a reasonable range of current differential pressure measurements based on the DPF's current carbon loading and the vehicle's current exhaust emissions during DPF low capture efficiency fault diagnosis. Based on this reasonable range, the method determines whether the differential pressure measurements collected by the DPF differential pressure sensor exhibit an increased error. If so, the diagnostic threshold used to diagnose low capture efficiency is corrected, and the corrected threshold is used to determine whether a DPF low capture efficiency fault has occurred. This method can thus determine whether a low capture efficiency fault has occurred even when the DPF differential pressure sensor's measurement values ​​exhibit a significant error, avoiding false or missed fault reports due to erroneous diagnostic conclusions. This ensures driving safety and exhaust emissions compliance for fuel-powered vehicles (particularly diesel-powered vehicles), while also reducing after-sales service costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 One of the flow charts of the method for diagnosing a low capture efficiency fault of a DPF provided in an embodiment of the present invention;

[0041] Figure 2 This is a diagram introducing the properties of the PT filtering algorithm;

[0042] Figure 3 A flowchart of the process of establishing the correspondence between the calibrated carbon load, the exhaust gas volume, and the pressure difference range provided in an embodiment of the present invention;

[0043] Figure 4 This is a second flow chart of a method for diagnosing a low capture efficiency fault of a DPF provided in an embodiment of the present invention;

[0044] Figure 5 A schematic diagram of the structure of a diagnostic device for a low capture efficiency fault of a DPF provided in an embodiment of the present invention;

[0045] Figure 6 A schematic structural diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0046] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention will be further described below with reference to the accompanying drawings and examples. However, the example embodiments can be implemented in various forms and should not be understood as being limited to the embodiments described herein; on the contrary, these embodiments are provided to make the present invention more comprehensive and complete, and to fully convey the concepts of the example embodiments to those skilled in the art. The same figure marks in the figures represent the same or similar structures, and their repeated descriptions will be omitted. The words expressing position and direction described in the present invention are all explained with reference to the accompanying drawings as examples, but changes can be made as needed, and the changes made are all included in the scope of protection of the present invention. The drawings of the present invention are only used to illustrate the relative position relationship and do not represent the true proportion.

[0047] It should be noted that specific details are set forth in the following description to facilitate a full understanding of the present invention. However, the present invention can be implemented in a variety of ways different from those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below. The subsequent description of the specification is a preferred embodiment of the present application, but the description is for the purpose of illustrating the general principles of the present application and is not intended to limit the scope of the present application. The scope of protection of the present application shall be determined as defined by the appended claims.

[0048] The following describes in detail the method for diagnosing a low capture efficiency fault of a DPF and related hardware provided by an embodiment of the present invention in conjunction with the accompanying drawings.

[0049] The embodiment of the present invention provides a method for diagnosing a low capture efficiency fault of a DPF, such as Figure 1 Shown, including:

[0050] S100: Determine whether a diagnosis condition is met.

[0051] If the result of step S100 is yes, execute step S110; if the result of step S100 is no, continue waiting until the result is yes.

[0052] S110 : Obtain a pressure difference measurement value between a DPF upstream pressure and a DPF downstream pressure collected by a DPF pressure difference sensor.

[0053] S120 : Determine a current carbon load of the DPF and a current amount of exhaust gas emitted by the vehicle, and determine a pressure difference range according to the carbon load and the exhaust gas amount.

[0054] In specific implementations, the pressure differential range is an interval with an upper limit and a lower limit. Therefore, determining the pressure differential range based on the carbon loading and the exhaust gas volume means determining the upper and lower limits of the pressure differential range based on the carbon loading and the exhaust gas volume. Specifically, the pressure differential range corresponding to the current carbon loading of the DPF and the current exhaust gas volume emitted by the vehicle can be determined by utilizing a pre-established correspondence (in the form of a function, curve, or mapping table) between carbon loading, exhaust gas volume, and pressure differential range. Generally, for the same carbon loading, the higher the exhaust gas volume, the higher the upper limit of the pressure differential range; similarly, for the same exhaust gas volume, the higher the carbon loading, the higher the upper limit of the pressure differential range.

[0055] S130: Determine whether the pressure difference measurement value is within the pressure difference range.

[0056] If the result of step S130 is no, step S140 is executed.

[0057] S140 , determining a diagnosis correction value according to the pressure difference measurement value and the pressure difference range, and correcting a basic diagnosis threshold according to the diagnosis correction value to obtain a corrected diagnosis threshold.

[0058] As an optional implementation, the process of correcting the basic diagnostic threshold according to the diagnostic correction value to obtain the corrected diagnostic threshold may specifically include:

[0059] If the pressure difference measurement value is greater than the pressure difference range (i.e., the pressure difference measurement value is greater than the upper limit of the pressure difference range), the basic diagnostic threshold is increased by the diagnostic correction value to obtain the corrected diagnostic threshold;

[0060] If the pressure difference measurement value is less than the pressure difference range (ie, the pressure difference measurement value is less than the lower limit of the pressure difference range), the basic diagnostic threshold is reduced by the diagnostic correction value to obtain the corrected diagnostic threshold.

[0061] In a specific implementation, the diagnostic correction value may be the difference between the pressure differential measurement value and the upper limit or lower limit of the pressure differential range. When the pressure differential measurement value is greater than the pressure differential range, the difference between the pressure differential measurement value and the upper limit of the pressure differential range is used as the diagnostic correction value. When the pressure differential measurement value is less than the pressure differential range, the difference between the pressure differential measurement value and the lower limit of the pressure differential range is used as the diagnostic correction value. Alternatively, a first correction relationship between the difference (including the difference from the upper limit and the difference from the lower limit) and the diagnostic correction value may be pre-established (for example, the first correction relationship may be set to a step function, a linear function, etc.), and the corresponding diagnostic correction value may be determined based on the first correction relationship. Alternatively, a second correction relationship between the pressure differential measurement value, the upper limit of the pressure differential range, the lower limit of the pressure differential range, and the diagnostic correction value may be pre-established, and the diagnostic correction value may be determined based on the second correction relationship. Other feasible implementations are also possible and are not limited in detail here.

[0062] As another optional implementation, the process of correcting the basic diagnostic threshold according to the diagnostic correction value to obtain the corrected diagnostic threshold may specifically include:

[0063] The diagnostic correction value is multiplied by the basic diagnostic threshold to obtain a corrected diagnostic threshold.

[0064] In a specific implementation, if the measured pressure differential value is greater than the pressure differential range (i.e., the measured pressure differential value is greater than the upper limit of the pressure differential range), the basic diagnostic threshold is a value greater than 1; if the measured pressure differential value is less than the pressure differential range (i.e., the measured pressure differential value is less than the lower limit of the pressure differential range), the basic diagnostic threshold is a value greater than 0 but less than 1. The diagnostic correction value can be determined by pre-establishing a third correction relationship (e.g., setting the third correction relationship to a step function, a linear function, etc.) between the differential values ​​(including the difference between the measured pressure differential value and the upper limit of the pressure differential range, and the difference between the measured pressure differential value and the lower limit of the pressure differential range) and the diagnostic correction value, and determining the corresponding diagnostic correction value based on the third correction relationship. Alternatively, the diagnostic correction value can be determined by pre-establishing a fourth correction relationship between the measured pressure differential value, the upper limit of the pressure differential range, the lower limit of the pressure differential range, and the diagnostic correction value, and determining the diagnostic correction value based on the fourth correction relationship. Other feasible implementations are also possible and are not limited herein.

[0065] S150: Determine whether the pressure difference measurement value is less than the corrected diagnosis threshold.

[0066] If the result of step S150 is yes, execute step S160; if the result of step S150 is no, return to step S100.

[0067] S160: Determine whether the duration during which the pressure difference measurement value is less than the modified diagnostic threshold is greater than a preset first time threshold.

[0068] If the result of step S160 is yes, execute step S190; if the result of step S160 is no, return to step S100.

[0069] S190: Determine whether a low capture efficiency fault occurs in the DPF.

[0070] After determining that the DPF has a low capture efficiency failure, other steps may be performed, such as issuing an alarm to the user through the vehicle's dashboard and recording the DPF low capture efficiency failure event in the Power Control Module (PCM) through the On-Board Diagnostics (OBD) system. These steps will not be elaborated here.

[0071] The method for diagnosing a DPF low capture efficiency failure provided by an embodiment of the present invention determines a reasonable range of values ​​for the current differential pressure measurement based on the DPF's current carbon loading and the vehicle's current exhaust emissions during DPF low capture efficiency diagnosis. Based on this reasonable range, it is determined whether the differential pressure measurement value collected by the DPF differential pressure sensor exhibits an increased error. If the error increases, the diagnostic threshold used to diagnose low capture efficiency is corrected, and the corrected diagnostic threshold is used to determine whether the DPF low capture efficiency failure has occurred. This method can thus determine whether a low capture efficiency failure has occurred even when the DPF differential pressure sensor's measurement value exhibits a significant error, avoiding false or missed fault reports due to erroneous diagnostic conclusions. This ensures driving safety and exhaust emissions compliance for fuel-powered vehicles (particularly diesel-powered vehicles), while also reducing after-sales service costs.

[0072] Furthermore, when the differential pressure measurement values ​​collected by the DPF differential pressure sensor do not show a significant increase in error, the diagnosis of the DPF low capture efficiency fault can be performed by the following steps. That is, the method further includes:

[0073] If the result of step S130 is yes, step S170 is executed.

[0074] S170: Determine whether the pressure difference measurement value is less than the basic diagnosis threshold.

[0075] If the result of step S170 is yes, execute step S180; if the result of step S170 is no, return to step S100.

[0076] S180: Determine whether the duration during which the pressure difference measurement value is less than the basic diagnosis threshold is greater than a preset second time threshold.

[0077] If the result of step S180 is yes, execute step S190; if the result of step S180 is no, return to step S100.

[0078] In a specific implementation process, the preset first time threshold and the preset second time threshold can be the same value or different values.

[0079] Optionally, the diagnostic condition includes at least one of the following:

[0080] (1) Within the preset time after the vehicle’s Electronic Control Unit (ECU) is powered on.

[0081] During specific implementation, the preset duration may be set to a shorter duration, such as two to three seconds.

[0082] (2) During the operation of the vehicle's engine, the temperature inside the DPF is greater than a preset temperature threshold, and the amount of exhaust gas currently emitted by the vehicle is greater than a preset exhaust gas threshold.

[0083] By performing a DPF low capture efficiency fault diagnosis when the vehicle ECU is powered on, low DPF capture efficiency faults can be detected early when the DPF differential pressure sensor has a large measurement error, thus avoiding hidden dangers while the vehicle is driving. By performing DPF low capture efficiency fault diagnosis when certain conditions are met during engine operation, the DPF can be effectively monitored.

[0084] Optionally, the current carbon load of the DPF can be determined specifically by the following method:

[0085] The carbon load sampling value is periodically determined according to the current engine speed and the current engine torque.

[0086] The current carbon load of the DPF is determined based on the periodically determined carbon load sampling values. Specifically, the current carbon load of the DPF is obtained by accumulating the carbon load sampling values ​​since the last regeneration process was completed.

[0087] During the specific implementation process, when the engine torque is constant, the greater the engine speed, the larger the corresponding carbon load sampling value; for any sampling time, when the engine speed is constant, the greater the engine torque, the larger the corresponding carbon load sampling value.

[0088] Optionally, the amount of exhaust gas currently emitted by the vehicle can be determined specifically by the following method:

[0089] An intake air flow rate of the engine is determined according to an intake air temperature of the engine and an intake air pressure of the engine.

[0090] The exhaust gas amount is determined according to an intake air flow rate of the engine and a fuel consumption amount of the engine.

[0091] In a specific implementation, the engine intake temperature and the engine intake pressure can be measured by an intake temperature sensor and a barometric pressure sensor (BPS), respectively, and the engine fuel consumption can be calculated by the ECU using existing methods, which will not be repeated here.

[0092] In addition, the amount of exhaust gas currently emitted by the vehicle can also be determined by other means, which will not be elaborated here. Furthermore, no matter how the amount of exhaust gas currently emitted by the vehicle is determined, since the exhaust gas amount itself is a continuously changing value, and the determination process will cause a delay in obtaining the value, in order to avoid extreme errors caused by instantaneous mutations in the value of the exhaust gas amount due to interference from external factors, the determined exhaust gas amount can be filtered before determining the pressure difference range based on the carbon load and the exhaust gas amount. For example, the PT filtering algorithm can be used to filter the exhaust gas amount. Accordingly, the step S120, determining the current carbon load of the DPF and the current exhaust gas emitted by the vehicle, and determining the pressure difference range based on the carbon load and the exhaust gas amount, specifically includes:

[0093] Determine the current carbon load of the DPF and the current exhaust gas volume emitted by the vehicle, filter the current exhaust gas volume emitted by the vehicle using a PT filtering algorithm, and obtain the filtered exhaust gas volume;

[0094] The pressure difference range is determined according to the carbon loading and the amount of filtered exhaust gas.

[0095] In a specific implementation process, the PT filtering algorithm may include: Figure 2 The PT1 filtering algorithm, PT2 filtering algorithm, PT n Filtering algorithm, etc. Among them, is the gain (Proportionality constant), T is the time constant, is the angular frequency, D is the damping coefficient, n is the degree of order.

[0096] Furthermore, the time constant of the PT filtering algorithm is T The length is determined based on the length of the air passage between the supercharger of the engine and the vehicle exhaust after-treatment device.

[0097] Furthermore, the longer the airway length is, the shorter the time constant is. TIn the specific implementation process, the airway length and time constant can be pre-established T The corresponding relationship (such as a monotonically increasing linear function, etc.) is used to calculate the time constant of the PT filtering algorithm. T Make confirmation.

[0098] Optionally, the corresponding relationship between the current carbon load of the DPF and the current exhaust gas volume emitted by the vehicle and the pressure difference range can be established in the following manner:

[0099] Multiple tests are performed, wherein the target DPF used in each test has a different degree of damage. In a specific implementation, multiple target DPFs may be prepared, each with a different degree of damage. Alternatively, a single target DPF may be prepared and subjected to a predetermined degree of damage before each test (e.g., a 1 cm deep indentation with an area of ​​30% of the rear end surface of the DPF may be made each time the target DPF is tested). This is not limited here.

[0100] like Figure 3 As shown, each time a test is performed, the following steps are performed in sequence:

[0101] S200: Determine whether all tests have been completed.

[0102] If all tests are not completed, proceed to step S210; if all tests are completed, proceed to step S250.

[0103] S210 , performing a carbon deposition cycle on the target DPF.

[0104] S220: Determine whether the test has been conducted under all the World Harmoized Transient Cycle (WHTC) at all the calibrated carbon loadings, where the calibrated carbon loadings are multiple preset values.

[0105] If the global uniform state test cycle has not been performed at all calibrated carbon loadings in this test, step S230 is performed; if the global uniform state test cycle has been performed at all calibrated carbon loadings in this test, the test is terminated and the process returns to step S200.

[0106] S230: Determine whether the current carbon load of the target DPF reaches a calibrated carbon load.

[0107] 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 to perform the carbon deposition cycle of step S210 .

[0108] 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 volumes during the WHTC process, and determine the pressure difference range based on the measured pressure difference values. After completing step S240, return to step S210.

[0109] S250: Establish the corresponding relationship according to the calibrated carbon load, exhaust gas volume, and pressure difference range obtained from each test.

[0110] The above solution is described in detail below using a specific example. In this example, the lower limit of the pressure difference range is uniformly set to 0. Figure 4 As shown, the specific steps include:

[0111] S300. Determine whether any of the following conditions is met: ① within a preset time after the vehicle's ECU is powered on; ② during engine operation of the vehicle, the temperature in the DPF is greater than a preset temperature threshold, and the amount of exhaust gas currently emitted by the vehicle is greater than a preset exhaust gas threshold.

[0112] 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.

[0113] S310 : Obtain a pressure difference measurement value between a DPF upstream pressure and a DPF downstream pressure collected by a DPF pressure difference sensor.

[0114] S320: Determine the current carbon load of the DPF and the current exhaust gas volume emitted by the vehicle, and determine an upper limit value of the pressure difference range based on the carbon load and the exhaust gas volume.

[0115] S331. Determine whether the pressure difference measurement value is less than 0.

[0116] If the result of step S331 is yes, execute step S341; if the result of step S331 is no, execute step S332.

[0117] S332: Determine whether the pressure difference measurement value is greater than the upper limit of the pressure difference range.

[0118] If the result of step S332 is yes, execute step S342; if the result of step S332 is no, execute step S370.

[0119] S341 , subtract the pressure difference measurement value from 0 to determine a diagnosis correction value, and subtract the diagnosis correction value from the basic diagnosis threshold to obtain a modified diagnosis threshold. Execute step S350 .

[0120] S342: Subtract the upper limit of the pressure difference range from the pressure difference measurement value to determine a diagnosis correction value, and add the basic diagnosis threshold value to the diagnosis correction value to obtain a modified diagnosis threshold value. Execute step S350.

[0121] S350: Determine whether the pressure difference measurement value is less than the corrected diagnosis threshold.

[0122] If the result of step S350 is yes, execute step S360; if the result of step S350 is no, return to step S300.

[0123] S360: Determine whether the duration during which the pressure difference measurement value is less than the modified diagnostic threshold is greater than a preset time threshold.

[0124] If the result of step S360 is yes, execute step S390; if the result of step S360 is no, return to step S300.

[0125] S370: Determine whether the pressure difference measurement value is less than the basic diagnosis threshold.

[0126] If the result of step S370 is yes, execute step S380; if the result of step S370 is no, return to step S300.

[0127] S380: Determine whether the duration during which the pressure difference measurement value is less than the basic diagnosis threshold is greater than a preset time threshold.

[0128] If the result of step S380 is yes, execute step S390; if the result of step S380 is no, return to step S300.

[0129] S390: Determine whether a low capture efficiency fault occurs in the DPF.

[0130] Based on the same inventive concept, the embodiment of the present invention also provides a diagnostic device for a low capture efficiency failure of a DPF, such as Figure 5 Shown, including:

[0131] The measuring module M1 is used to obtain a pressure difference measurement value between a DPF upstream pressure and a DPF downstream pressure collected by a DPF pressure difference sensor when a diagnostic condition is determined to be met;

[0132] 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 based on the carbon load and the exhaust gas volume;

[0133] The DPF low capture efficiency fault diagnosis module M3 is used to determine a diagnostic correction value based on the pressure difference measurement value and the pressure difference range if the pressure difference measurement value is not within the pressure difference range, and to correct the basic diagnostic threshold value according to the diagnostic correction value to obtain a corrected diagnostic threshold value; if the duration for which the pressure difference measurement value is less than the corrected diagnostic threshold value is greater than a preset first time threshold, it is determined that a DPF low capture efficiency fault occurs.

[0134] Optionally, the DPF low capture efficiency fault diagnosis module M3 is further configured to:

[0135] If the pressure difference measurement value is within the pressure difference range, and the duration of the pressure difference measurement value being less than the basic diagnosis threshold value is greater than a preset second time threshold, it is determined that a low trapping efficiency fault occurs in the DPF.

[0136] Optionally, determining the current carbon load of the DPF includes:

[0137] Periodically determining a carbon load sampling value based on a current engine speed and a current engine torque;

[0138] The current carbon load of the DPF is determined according to each of the carbon load sampling values ​​determined periodically.

[0139] Optionally, determining the amount of exhaust gas currently emitted by the vehicle includes:

[0140] determining an intake air flow rate of the engine based on an intake air temperature of the engine and an intake air pressure of the engine;

[0141] The exhaust gas amount is determined according to an intake air flow rate of the engine and a fuel consumption amount of the engine.

[0142] Optionally, determining a current carbon load of the DPF and a current amount of exhaust gas emitted by the vehicle, and determining a pressure difference range according to the carbon load and the exhaust gas amount, includes:

[0143] Determine the current carbon load of the DPF and the current exhaust gas volume emitted by the vehicle, filter the current exhaust gas volume emitted by the vehicle through the PT filtering algorithm, and obtain the filtered exhaust gas volume;

[0144] determining a differential pressure range based on the carbon loading and the filtered exhaust gas volume;

[0145] The time constant of the PT filtering algorithm is determined according to the length of the airway between the supercharger of the engine and the vehicle exhaust after-treatment device, and the longer the airway length is, the larger the time constant is.

[0146] Optionally, the diagnostic condition includes at least one of the following:

[0147] Within the preset time after the vehicle's electronic control unit ECU is powered on;

[0148] During engine operation of the vehicle, the temperature inside the DPF is greater than a preset temperature threshold, and the amount of exhaust gas currently emitted by the vehicle is greater than a preset exhaust gas amount threshold.

[0149] Optionally, determining the pressure difference range according to the carbon load and the exhaust gas volume specifically includes:

[0150] Using the corresponding relationship between carbon load, exhaust gas volume and pressure differential range, determine the pressure differential range corresponding to the current carbon load of the DPF and the current exhaust gas volume emitted by the vehicle;

[0151] The corresponding relationship is established in the following manner:

[0152] The following test is performed multiple times, wherein the target DPF used in each test has a different degree of damage treatment: the target DPF is subjected to a carbon deposition cycle, and when the current carbon loading of the target DPF reaches a calibrated carbon loading, the target DPF is subjected to a World Harmonized Temperature Test (WHTC) cycle, during which the pressure differential between the upstream and downstream pressures of the target DPF corresponding to different exhaust gas volumes is measured, and a pressure differential range is determined based on the measured pressure differential values; the target DPF is then subjected to carbon deposition cycles again until the WHTC cycle is performed at all calibrated carbon loadings, and the test is terminated.

[0153] The corresponding relationship is established based on the calibrated carbon load, exhaust gas volume and pressure difference range obtained from each test.

[0154] It should be understood that the above-described embodiment of the diagnostic device for a DPF low capture efficiency fault is merely illustrative. For example, the module division is merely a logical functional division. In actual implementation, other division methods may be employed. For example, multiple modules or components may be combined or integrated into another system, or some features may be ignored or not executed. The functional modules in the embodiment may be integrated into a single processing module, or each module may exist physically separately, or two or more modules may be integrated into a single module. The integrated modules may be implemented in either hardware or software functional modules. If the integrated modules are implemented as software functional modules and sold or used as independent products, they may be stored in a computer-readable storage medium.

[0155] Since the principle of solving the problem by the diagnostic device for low capture efficiency failure of DPF is basically consistent with the diagnostic method for low capture efficiency failure of DPF, the implementation of the diagnostic device for low capture efficiency failure of DPF can refer to the implementation of the diagnostic method for low capture efficiency failure of DPF, which will not be repeated here.

[0156] Based on the same inventive concept, an embodiment of the present invention further provides an electronic device, such as Figure 6 As shown, it includes: a processor 1100 and a memory 1200 for storing executable instructions of the processor 1100; wherein, the processor 1100 is configured to execute the instructions to implement the reliability testing method of the vehicle exhaust after-treatment device.

[0157] During specific implementation, the device may have relatively large differences due to different configurations or performances, and may include one or more processors 1100, a memory 1200, and a computer-readable storage medium 1300. The memory 1200 and / or the computer-readable storage medium 1300 may include one or more applications 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. The memory 1200 and the computer-readable storage medium 1300 may be temporary storage or persistent storage. The application 1310 may include one or more modules ( Figure 6 (not shown), 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 ( Figure 6 ); one or more network interfaces 1400, wherein the network interface 1400 includes a wired network interface 1410 and / or a wireless network interface 1420; and one or more input and output interfaces 1430.

[0158] Based on the same inventive concept, an embodiment of the present invention further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and the computer program is used to implement the reliability testing method of the vehicle exhaust after-treatment device.

[0159] The method and related hardware for diagnosing a DPF low capture efficiency fault, provided in an embodiment of the present invention, determine a reasonable range of current differential pressure measurements based on the DPF's current carbon loading and the vehicle's current exhaust emissions during DPF low capture efficiency fault diagnosis. Based on this reasonable range, the method determines whether the differential pressure measurements collected by the DPF differential pressure sensor exhibit an increased error. If so, the diagnostic threshold used to diagnose low capture efficiency is corrected, and the corrected threshold is used to determine whether a DPF low capture efficiency fault has occurred. This method can thus determine whether a low capture efficiency fault has occurred even when the DPF differential pressure sensor's measurement values ​​exhibit a significant error, avoiding false or missed fault reports due to erroneous diagnostic conclusions. This ensures driving safety and exhaust emissions compliance for fuel-powered vehicles (particularly diesel-powered vehicles), while also reducing after-sales service costs.

[0160] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present application may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0161] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0162] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0163] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0164] Obviously, those skilled in the art may make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

Claims

1. A method for diagnosing a low capture efficiency fault of a particulate filter DPF, characterized in that: include: When it is determined that the diagnostic condition is met, a pressure difference measurement value between a DPF upstream pressure and a DPF downstream pressure collected by a DPF pressure difference sensor is obtained; Determining a current carbon load of the DPF and a current amount of exhaust gas emitted by the vehicle, and determining a pressure differential range based on the carbon load and the exhaust gas, including: determining a pressure differential range corresponding to the current carbon load of the DPF and the current amount of exhaust gas emitted by the vehicle using a correspondence between the carbon load, the exhaust gas amount, and the pressure differential range; If the pressure difference measurement value is not within the pressure difference range, determining a diagnosis correction value according to the pressure difference measurement value and the pressure difference range, and correcting the basic diagnosis threshold according to the diagnosis correction value to obtain a corrected diagnosis threshold; If the duration of the pressure difference measurement value being less than the modified diagnostic threshold value is greater than a preset first time threshold value, determining that a low trapping efficiency fault occurs in the DPF; The corresponding relationship is established in the following manner: The following test is performed multiple times, wherein the target DPF used in each test has a different degree of damage treatment: the target DPF is subjected to a carbon deposition cycle, and when the current carbon loading of the target DPF reaches a calibrated carbon loading, the target DPF is subjected to a World Harmonized Temperature Test (WHTC) cycle, during which the pressure differential between the upstream and downstream pressures of the target DPF corresponding to different exhaust gas volumes is measured, and a pressure differential range is determined based on the measured pressure differential values; the target DPF is then subjected to carbon deposition cycles again until the WHTC cycle is performed at all calibrated carbon loadings, and the test is terminated. The corresponding relationship is established based on the calibrated carbon load, exhaust gas volume and pressure difference range obtained from each test.

2. The method according to claim 1, wherein The method further comprises: If the pressure difference measurement value is within the pressure difference range, and the duration of the pressure difference measurement value being less than the basic diagnosis threshold value is greater than a preset second time threshold, it is determined that a low trapping efficiency fault occurs in the DPF.

3. The method according to claim 1, wherein Determining the current carbon load of the DPF includes: Periodically determining a carbon load sampling value based on a current engine speed and a current engine torque; The current carbon load of the DPF is determined according to each of the carbon load sampling values ​​determined periodically.

4. The method according to claim 1, wherein The determining of the amount of exhaust gas currently emitted by the vehicle includes: determining an intake air flow rate of the engine based on an intake air temperature of the engine and an intake air pressure of the engine; The exhaust gas amount is determined according to an intake air flow rate of the engine and a fuel consumption amount of the engine.

5. The method according to claim 1 or 4, wherein: Determining the current carbon load of the DPF and the current exhaust gas volume emitted by the vehicle, and determining the pressure difference range according to the carbon load and the exhaust gas volume, includes: Determine the current carbon load of the DPF and the current exhaust gas volume emitted by the vehicle, filter the current exhaust gas volume emitted by the vehicle using a PT filtering algorithm, and obtain the filtered exhaust gas volume; determining a pressure differential range based on the carbon loading and the filtered exhaust gas volume; The time constant of the PT filtering algorithm is determined according to the length of the airway between the supercharger of the engine and the vehicle exhaust after-treatment device, and the longer the airway length is, the larger the time constant is.

6. The method according to claim 1, wherein The diagnostic conditions include at least one of the following: Within the preset time after the vehicle's electronic control unit ECU is powered on; During engine operation of the vehicle, the temperature inside the DPF is greater than a preset temperature threshold, and the amount of exhaust gas currently emitted by the vehicle is greater than a preset exhaust gas amount threshold.

7. A diagnostic device for low capture efficiency failure of DPF, characterized in that: The diagnostic device is used to implement the diagnostic method for a low trapping efficiency fault of a particulate trap DPF according to any one of claims 1 to 6; the diagnostic device comprises: a measurement module, configured to obtain a pressure difference measurement value between a DPF upstream pressure and a DPF downstream pressure acquired by a DPF pressure difference sensor when a diagnostic condition is determined to be met; A 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 based on the carbon load and the exhaust gas volume, including: using the corresponding relationship between the carbon load, the exhaust gas volume and the differential pressure range to determine the differential pressure range corresponding to the current carbon load of the DPF and the current exhaust gas volume emitted by the vehicle; a DPF low trapping efficiency fault diagnosis module configured to, if the pressure differential measurement value is not within the pressure differential range, determine a diagnosis correction value based on the pressure differential measurement value and the pressure differential range, and correct a basic diagnosis threshold value based on the diagnosis correction value to obtain a corrected diagnosis threshold value; and determine that a DPF low trapping efficiency fault occurs if the duration for which the pressure differential measurement value is less than the corrected diagnosis threshold value is greater than a preset first time threshold; The corresponding relationship is established in the following manner: The following test is performed multiple times, wherein the target DPF used in each test has a different degree of damage treatment: the target DPF is subjected to a carbon deposition cycle, and when the current carbon loading of the target DPF reaches a calibrated carbon loading, the target DPF is subjected to a World Harmonized Temperature Test (WHTC) cycle, during which the pressure differential between the upstream and downstream pressures of the target DPF corresponding to different exhaust gas volumes is measured, and a pressure differential range is determined based on the measured pressure differential values; the target DPF is then subjected to carbon deposition cycles again until the WHTC cycle is performed at all calibrated carbon loadings, and the test is terminated. The corresponding relationship is established based on the calibrated carbon load, exhaust gas volume and pressure difference range obtained from each test.

8. An electronic device, characterized in that: include: a processor and a memory for storing instructions executable by the processor; The processor is configured to execute the instructions to implement the method for diagnosing a low trapping efficiency fault of a particulate trap (DPF) according to any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, and the computer program is used to implement the method for diagnosing a low trapping efficiency fault of a particulate trap DPF according to any one of claims 1 to 6.

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