Abnormality diagnosis method for engine system

Abstract

The application provides an abnormality diagnosis method applied to an engine system, and belongs to the technical field of engine control. The abnormality diagnosis method applied to the engine system comprises the following steps: for each engine operating parameter, a first-order low-pass filtering is performed by using a corresponding filtering coefficient to obtain a corresponding filtering value; in response to the engine operating parameter and the filtering value, it is determined that the engine working condition is a steady state condition, then a filtering value of an EGR valve outlet pressure in a first preset number of sampling periods is preprocessed to obtain an outlet pressure array; the outlet pressure array at least comprises one of a maximum value array, a minimum value array and a mean value array; according to the stability of the speed change rate, whether the outlet pressure signal is faulty is determined by using the number of times that the difference between adjacent elements of the outlet pressure array is greater than a dynamic numerical threshold value; and the dynamic numerical threshold value is determined according to the engine operating parameter.

Description

Technical Field

[0001] This invention relates to the field of engine control technology, and in particular to a method for diagnosing anomalies in engine systems. Background Technology

[0002] Exhaust gas recirculation (EGR) draws exhaust gases from the exhaust system and introduces them into the intake system. Studies have shown that EGR systems have certain advantages in improving emissions, reducing fuel consumption, and improving anti-knock capabilities.

[0003] The gas pressure on both sides (inlet and outlet) of the EGR valve is a crucial input for EGR rate control, determining the accuracy of exhaust gas flow estimation and EGR valve opening control, thus affecting the precision of the EGR rate. Therefore, it is necessary to promptly check whether the EGR valve outlet gas pressure signal is normal to avoid affecting EGR rate control and causing adverse effects on engine performance. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art and proposes an anomaly diagnosis method for engine systems.

[0005] In a first aspect, embodiments of the present invention provide a method for anomaly diagnosis applied to an engine system, comprising:

[0006] For each engine operating parameter, a first-order low-pass filter is performed using the corresponding filter coefficient to obtain the corresponding filter value. The engine operating parameters include at least engine speed parameters and engine-related parameters. The filter coefficient for each engine-related parameter is determined based on the stability of the engine speed parameters. The engine speed parameters include engine speed and rate of change of engine speed. The engine-related parameters include at least the EGR valve outlet pressure.

[0007] In response to determining that the engine operating condition is a steady-state condition using engine operating parameters and filter values, the filter values ​​of the EGR valve outlet pressure within a first preset number of sampling periods are preprocessed to obtain an outlet pressure array; the outlet pressure array includes at least one of a maximum value array, a minimum value array, and a mean value array;

[0008] Based on the stability of the speed change rate, the number of times the difference between adjacent elements of the outlet pressure array exceeds the dynamic value threshold is used to determine whether the outlet pressure signal is faulty; the dynamic value threshold is determined based on the engine operating parameters.

[0009] According to an embodiment of the present invention, the engine-related parameters include at least one of the following: intake air density into the cylinder, throttle opening, mixing valve opening, EGR valve opening, EGR valve inlet pressure, and EGR valve outlet pressure; the method for calculating the filter coefficients corresponding to the engine-related parameters includes:

[0010] Determine whether the engine speed parameters are in a stable state;

[0011] If the engine speed parameters are stable, the current filter coefficient is calculated based on the preset calibration filter coefficient and the engine speed; the calibration filter coefficient is obtained by bench testing the engine at the preset speed.

[0012] If the engine speed parameters are unstable, the current filter coefficient is calculated based on the preset self-learning coefficient.

[0013] According to an embodiment of the present invention, the filtered values ​​of the EGR valve outlet pressure within a first preset number of sampling periods are preprocessed to obtain an outlet pressure array, and the process further includes:

[0014] Using engine operating parameters and filter values, the engine operating condition is determined, specifically including:

[0015] By using engine operating parameters and the difference between engine operating parameters and corresponding filter values, it can be determined whether the engine meets the signal stability conditions.

[0016] In response to the engine signal stabilization condition, the target EGR rate remains unchanged, and it is determined whether the engine meets the EGR valve gas stabilization condition.

[0017] In response to the engine meeting the EGR valve gas stability condition, the control target EGR valve opening remains unchanged, and it is determined whether the engine meets the EGR valve opening stability condition.

[0018] If the engine meets the EGR valve opening stability condition, then the engine operating condition is determined to be a steady-state condition.

[0019] According to an embodiment of the present invention, controlling the target EGR valve opening to remain constant and determining whether the engine meets the EGR valve opening stability condition includes:

[0020] Read the first average value of the target EGR valve opening within a first preset time period;

[0021] The target EGR valve opening is kept constant at the first average value.

[0022] Using the EGR valve opening degree and its filtered value, determine whether the EGR valve opening degree is stable within the second preset time period;

[0023] If so, the engine is determined to meet the EGR valve opening stability condition;

[0024] If not, the engine is determined not to meet the EGR valve opening stability condition, and the outlet pressure signal stability check is terminated.

[0025] According to an embodiment of the present invention, a method for obtaining a second preset time includes:

[0026] In response to the EGR valve opening being 0, the second preset time is the time required for the calibrated fresh air to flow from the mixing valve outlet to the booster inlet;

[0027] In response to an EGR valve opening greater than 0, the second preset time is the time required for exhaust gas to flow from the gasoline particulate filter outlet to the mixing valve outlet at the current EGR valve opening, as determined by calibration.

[0028] According to an embodiment of the present invention, the filtered values ​​of the EGR valve outlet pressure within a first preset number of sampling periods are preprocessed to obtain an outlet pressure array, including:

[0029] Read the maximum and minimum values ​​of the filtered values ​​of the EGR valve outlet pressure within a first preset number of sampling periods to obtain a first maximum value array and a first minimum value array;

[0030] Remove the first second preset number of elements from the first maximum value array and the first minimum value array, and remove the maximum value and the corresponding minimum value that are 0 to obtain the second maximum value array and the second minimum value array;

[0031] Divide the data into a second maximum value array and a second minimum value array according to the third preset quantity, obtain the maximum value interval and the minimum value interval of the third preset quantity, calculate the average value of each interval, remove the average value of the maximum value and the corresponding average value of the minimum value that are 0, and obtain the final maximum value array and the final minimum value array.

[0032] The mean array is obtained by averaging the corresponding elements of the final maximum value array and the final minimum value array.

[0033] According to an embodiment of the present invention, a method for obtaining a second preset quantity includes:

[0034] Based on the filtered value of the rotational speed, the second preset quantity is obtained by querying the first calibration table; the first calibration table records the mapping relationship between the range of filtered values ​​of rotational speed and the second preset quantity.

[0035] According to an embodiment of the present invention, based on the stability of the rotational speed change rate, the method determines whether a fault has occurred in the outlet pressure signal by utilizing the number of times the difference between adjacent elements of the outlet pressure array exceeds a dynamic numerical threshold, including:

[0036] Using the rate of change of rotational speed and the filtered value of the rate of change of rotational speed, it is determined whether the rate of change of rotational speed is stable within a third preset time period;

[0037] If the speed change rate is unstable within the third preset time, the judgment is made based on the mean array in the outlet pressure array. The number of times the absolute value of the difference between adjacent elements in the mean array is greater than the first dynamic threshold is counted. When the first count exceeds the first fault count threshold, the outlet pressure signal is determined to be faulty.

[0038] If the speed change rate is stable within the third preset time, the judgment is made based on the maximum value array and minimum value array in the outlet pressure array. The number of times the absolute value of the difference between adjacent elements in the maximum value array is greater than the second dynamic threshold, the number of times the absolute value of the difference between adjacent elements in the minimum value array is greater than the third dynamic threshold, and the number of times the absolute value of the difference between the corresponding elements of the maximum and minimum value arrays is greater than the fourth dynamic threshold are counted. When the second, third, or fourth count exceeds the second fault count threshold, the outlet pressure signal is determined to be faulty.

[0039] The first dynamic threshold, the second dynamic threshold, the third dynamic threshold, and the fourth dynamic threshold are determined at least based on the target EGR rate, the filtered value of the rotational speed, the target EGR valve opening, the EGR valve inlet temperature, the EGR valve inlet pressure, and the filtered value of the EGR valve inlet pressure.

[0040] The first fault count threshold and the second fault count threshold are determined at least based on the ratio of the fresh air intake flow rate into the cylinder to the pressure at the outlet and inlet of the mixing valve.

[0041] According to an embodiment of the present invention, the method for calculating the first dynamic threshold, the second dynamic threshold, the third dynamic threshold, and the fourth dynamic threshold includes:

[0042] The first dynamic threshold is obtained based on the first preset default threshold, the minimum absolute value of the difference between adjacent elements of the mean array, the first correction factor, and the second correction factor.

[0043] The second dynamic threshold is obtained based on the second preset default threshold, the minimum absolute value of the difference between adjacent elements of the maximum value array, the third correction factor, and the fourth correction factor;

[0044] The third dynamic threshold is obtained based on the second preset default threshold, the minimum value of the absolute value of the difference between adjacent elements of the minimum value array, the third correction factor, and the fourth correction factor.

[0045] The fourth dynamic threshold is obtained based on the second preset default threshold, the minimum value of the absolute value of the difference between the corresponding elements of the maximum and minimum value arrays, the third correction factor, and the fourth correction factor.

[0046] The first correction factor is calculated using a first preset value, a target EGR rate, and a calibration value; the second correction factor is calculated using a second preset value, an EGR valve inlet temperature, an EGR valve inlet pressure, and a filtered value of the EGR valve inlet pressure; the third correction factor is calculated using a third preset value, a target EGR rate, and a calibration value; and the fourth correction factor is calculated using a fourth preset value, an EGR valve inlet temperature, an EGR valve inlet pressure, and a filtered value of the EGR valve inlet pressure.

[0047] The calibration values ​​are obtained by querying a preset second calibration table; the second calibration table stores the corresponding calibration values, indexed by the filtered value of the rotational speed and the target EGR valve opening.

[0048] According to an embodiment of the present invention, the method for calculating the first fault count threshold and the second fault count includes:

[0049] Obtain the first ratio of the average absolute value of the fresh air intake flow rate entering the cylinder under the condition of signal stability to the preset flow rate;

[0050] Obtain a second ratio between the average value of the mixing valve outlet pressure and the average value of the mixing valve inlet pressure under the condition of signal stability.

[0051] The calculation steps for the first fault count threshold are as follows: the first base value is obtained by inputting the first ratio into the third or fourth calibration table; the second base value is obtained by inputting the second ratio into the fifth or sixth calibration table; the first base value and the second base value are multiplied together and rounded to determine the first fault count threshold.

[0052] The third calibration table is used when the EGR valve is closed, and stores the corresponding first basic value indexed by the first ratio; the fifth calibration table is used when the EGR valve is closed, and stores the corresponding second basic value indexed by the second ratio; the fourth calibration table is used when the EGR valve is not closed, and stores the corresponding first basic value indexed by the first ratio; the sixth calibration table is used when the EGR valve is not closed, and stores the corresponding second basic value indexed by the second ratio.

[0053] The calculation steps for the second fault count threshold are as follows: the third base value is obtained by inputting the first ratio into the seventh or eighth calibration table; the fourth base value is obtained by inputting the second ratio into the ninth or tenth calibration table; the third base value and the fourth base value are multiplied together and rounded to determine the second fault count threshold.

[0054] The seventh calibration table is used when the EGR valve is closed, and stores the corresponding third basic value indexed by the first ratio; the ninth calibration table is used when the EGR valve is closed, and stores the corresponding fourth basic value indexed by the second ratio; the eighth calibration table is used when the EGR valve is not closed, and stores the corresponding third basic value indexed by the first ratio; the tenth calibration table is used when the EGR valve is not closed, and stores the corresponding fourth basic value indexed by the second ratio.

[0055] A second aspect of the present invention provides an anomaly diagnosis system for an engine system, which can be used to implement the above-described anomaly diagnosis method for an engine system, comprising:

[0056] The parameter filtering module is used to perform first-order low-pass filtering on each engine operating parameter using the corresponding filtering coefficients to obtain the corresponding filtered value. The engine operating parameters include at least engine speed parameters and engine-related parameters. The filtering coefficients for each engine-related parameter are determined based on the stability of the engine speed parameters. The engine speed parameters include engine speed and rate of change of engine speed. The engine-related parameters include at least the EGR valve outlet pressure.

[0057] The operating condition judgment module is used to determine that the engine operating condition is a steady state by using engine operating parameters and filter values. Then, it preprocesses the filter values ​​of the EGR valve outlet pressure within a first preset number of sampling periods to obtain an outlet pressure array. The outlet pressure array includes at least one of a maximum value array, a minimum value array, and a mean value array.

[0058] The stability check module is used to determine whether the outlet pressure signal is faulty by measuring the number of times the difference between adjacent elements of the outlet pressure array is greater than the dynamic value threshold, based on the stability of the speed change rate. The dynamic value threshold is determined based on the engine operating parameters.

[0059] A third aspect of the present invention provides an electronic device comprising: one or more processors; and a memory for storing one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors perform the above-described anomaly diagnosis method applied to an engine system.

[0060] A fourth aspect of the present invention also provides a computer-readable storage medium having executable instructions stored thereon, which, when executed by a processor, cause the processor to perform the above-described anomaly diagnosis method applied to an engine system.

[0061] The abnormal diagnosis method for engine systems provided by this invention introduces operating condition-based filter coefficient adjustment, strict steady-state judgment, and dynamic threshold decision, which achieves high reliability and high accuracy in verifying the stability of the EGR outlet pressure signal. This effectively avoids misjudgment under transient operating conditions or normal sensor fluctuations, and provides a guarantee for the precise control of the EGR rate. Attached Figure Description

[0062] Figure 1 This is a schematic diagram of the engine system involved in the technical solution disclosed herein;

[0063] Figure 2 This is a flowchart illustrating an anomaly diagnosis method for an engine system provided in an embodiment of the present invention.

[0064] Figure 3 A flowchart of another anomaly diagnosis method applied to an engine system provided in this disclosure embodiment;

[0065] Figure 4 A structural block diagram of an anomaly diagnosis system for an engine system provided in an embodiment of the present invention;

[0066] Figure 5 This is a structural block diagram of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0067] To enable those skilled in the art to better understand the technical solutions of the present invention, exemplary embodiments of the present invention are described below in conjunction with the accompanying drawings, including various details of the embodiments of the present invention to aid understanding. These should be considered merely exemplary. Therefore, those skilled in the art should recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present invention. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description.

[0068] Where there is no conflict, the various embodiments of the present invention and the features thereof may be combined with each other.

[0069] As used herein, the term “and / or” includes any and all combinations of one or more related enumerated entries.

[0070] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, the singular forms “a” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that when the terms “comprising” and / or “made of” are used in this specification, the presence of the stated feature, integral, step, operation, element, and / or component is specified, but the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or groups thereof is not excluded. Terms such as “connected” or “linked” are not limited to physical or mechanical connections but can include electrical connections, whether direct or indirect.

[0071] Unless otherwise specified, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art. It will also be understood that terms such as those defined in commonly used dictionaries should be interpreted as having the meaning consistent with their meaning in the context of the relevant art and the invention, and will not be interpreted as having an idealized or overly formal meaning unless expressly so defined herein.

[0072] In the technical solution of this invention, the collection, storage, use, processing, transmission, provision, and disclosure of user personal information all comply with relevant laws and regulations and do not violate public order and good morals. The use of user data in this technical solution follows relevant national laws and regulations (e.g., the "Information Security Technology - Personal Information Security Specification"). For example: appropriate measures are taken for personal information access control; restrictions are imposed on the display of personal information; the purpose of using personal information does not exceed the scope of direct or reasonable association; and explicit identity targeting is eliminated when using personal information to avoid precisely locating a specific individual.

[0073] Figure 1 This is a schematic diagram of the engine system involved in the technical solution disclosed herein. Figure 1As shown, an engine system generally includes an air filter 1; a mixing valve 2 connected to the air filter, configured to regulate the pressure at the outlet of the EGR valve 10, increasing the pressure difference across the EGR valve 10, with two airflow passages extending from the mixing valve 2; a compressor 3 connected to one of the airflow passages of the mixing valve 2; a throttle valve 4 connected to the compressor 3, wherein the throttle valve 4 has a boost temperature and pressure sensor at its inlet and an intake air temperature and pressure sensor at its outlet, and the throttle valve 4 body has a position sensor and an actuator; an engine 5 connected to the throttle valve 4, configured to compress fresh air for boosting; and a turbine 6 connected to the engine 5, configured to control the opening of the exhaust bypass valve. The following components are connected to the turbine 6: a catalyst 7; a particulate filter 8; an EGR cooler 9 installed on another airflow path of the mixing valve 2, configured to receive and cool the exhaust gas output from the particulate filter 8 to increase the exhaust gas flow rate; an EGR valve 10 connected at one end to the EGR cooler 9 and at the other end to the mixing valve 2, configured to control the exhaust gas flow rate entering the cylinder; a temperature sensor 11 installed between the EGR valve 10 and the EGR cooler 9, configured to detect the exhaust gas temperature entering the EGR valve 10; and a differential pressure sensor 12 connected to the EGR valve 10, configured to detect the pressure at the inlet and outlet of the EGR valve 10.

[0074] The gas pressure on both sides (inlet and outlet) of the EGR valve is a crucial input for EGR rate control, determining the accuracy of exhaust gas flow estimation and EGR valve opening control, thus affecting the precision of the EGR rate. Therefore, it is necessary to promptly check whether the EGR valve outlet gas pressure signal is normal to avoid affecting EGR rate control and causing adverse effects on engine performance.

[0075] To address at least one of the technical problems existing in the aforementioned related technologies, the present invention mainly focuses on strictly controlling the verification operating conditions and verifying the differences in the performance of the maximum and minimum values ​​under different cycles to determine whether an outlet pressure stability failure has occurred, so as to avoid affecting the EGR rate control accuracy in a timely manner.

[0076] This invention provides an anomaly diagnosis method for engine systems that improves the accuracy of verification. Figure 2 This is a flowchart illustrating an anomaly diagnosis method for an engine system provided by an embodiment of the present invention, as shown below. Figure 2 As shown, this embodiment of the invention provides an anomaly diagnosis method applied to an engine system, including:

[0077] S1. For each engine operating parameter, perform a first-order low-pass filter using the corresponding filter coefficient to obtain the corresponding filter value; wherein, the engine operating parameters include at least engine speed parameters and engine-related parameters; the filter coefficient corresponding to each engine-related parameter is determined based on the stability of the engine speed parameters; the engine speed parameters include speed and speed change rate; the engine-related parameters include at least the EGR valve outlet pressure.

[0078] The filter coefficients are dynamically adjusted according to the stability of the speed parameters, realizing adaptive optimization of filtering: when the speed is stable, the calibrated filter coefficients are normalized according to the speed to improve the accuracy of signal filtering; when the speed is unstable, the preset default coefficients are used to effectively filter out high-frequency noise in the parameter signal and retain the true signal change trend.

[0079] S2, in response to determining that the engine operating condition is a steady state by using engine operating parameters and filter values, preprocess the filter values ​​of the EGR valve outlet pressure within a first preset number of sampling periods to obtain an outlet pressure array; the outlet pressure array includes at least one of a maximum value array, a minimum value array, and a mean value array.

[0080] By using steady-state operating conditions as a prerequisite for pressure signal verification, the normal fluctuations in pressure signals caused by dynamic changes in engine operating conditions (such as sudden changes in engine speed, sudden changes in throttle opening, and EGR valve switching status) are eliminated. This solves the problem of misjudgment of faults caused by failure to distinguish operating conditions, and greatly improves the accuracy and reliability of pressure signal verification.

[0081] S3, based on the stability of the speed change rate, determines whether the outlet pressure signal is faulty by using the number of times the difference between adjacent elements of the outlet pressure array is greater than the dynamic value threshold; the dynamic value threshold is determined based on the engine operating parameters.

[0082] Specifically, different diagnostic rules are employed based on the stability of the engine speed change rate, achieving full coverage verification of pressure signals under both dynamic and steady-state engine operating conditions: when the engine speed change rate is unstable, the pressure signal fluctuation pattern differs from that in steady-state conditions, and using a mean array for diagnosis better reflects the signal characteristics; when the engine speed change rate is stable, the engine is in a strictly steady-state condition, and using a maximum and minimum value array for diagnosis can more accurately capture abnormal fluctuations in the pressure signal. Simultaneously, the dynamic numerical threshold is determined based on real-time engine parameters, avoiding the insufficient adaptability of fixed thresholds under different operating conditions, further improving the accuracy of the verification.

[0083] Based on the above embodiments, the engine-related parameters include at least one of the following: intake air density into the cylinder, throttle opening, mixing valve opening, EGR valve opening, EGR valve inlet pressure, and EGR valve outlet pressure; the calculation method for the filter coefficient corresponding to the engine-related parameters includes: determining whether the engine speed parameter is in a stable state; if the engine speed parameter is in a stable state, calculating the current filter coefficient based on a preset calibration filter coefficient and the engine speed; the calibration filter coefficient is obtained by bench testing an engine at a preset speed; if the engine speed parameter is in an unstable state, calculating the current filter coefficient based on a preset self-learning coefficient.

[0084] First, for the engine speed n and the rate of change of engine speed dn (which is obtained by dividing the difference between the engine speed n in the current sampling period and the engine speed in the previous sampling period by the sampling period), we can calculate the engine speed n and the rate of change of engine speed dn. ), Fresh air intake density into the cylinder Throttle opening Mixing valve opening EGR valve opening GPF export pressure EGR valve inlet gas pressure (referred to as EGR valve inlet pressure) And the EGR valve outlet gas pressure (referred to as EGR valve outlet pressure). The filtering process uses the same formula, where X can be the engine speed. Engine speed change rate Fresh air intake density entering the cylinder and throttle opening Mixing valve opening EGR valve opening GPF export pressure EGR valve inlet pressure and EGR valve outlet pressure Any one of them.

[0085] ,

[0086] in, Let X be the value of the Nth sampling period. The value of X after first-order low-pass filtering. The filtered X value is the value of the Nth sampling period. The filtered X value is the value after filtering in the (N-1)th sampling period, where N = 1, 2, 3, ... Equal to the 0th sampling period Sampling period In this example, it took 10ms. The filter coefficients are obtained as follows:

[0087] (1) Filtering coefficients for engine speed n The method for obtaining it is as follows: Default coefficient Take 0.05.

[0088] Furthermore, in The conditions are met continuously for a preset time. This indicates that the engine speed is in a stable state (with minimal speed fluctuations). The threshold coefficient is also included. In this example, we use 0.05. This example takes 0.1s.

[0089] (2) Filtering coefficient of engine speed change rate dn The method for obtaining it is as follows:

[0090] Default coefficient Take 0.05. The filter coefficients are learned correction coefficients, with an initial value of 0, which are continuously learned and updated, and can be saved after the vehicle is powered off.

[0091] Optionally, Adaptive online learning based on model reference. The ECU has a built-in reference model to predict the ideal characteristics of the filtered signal for the rate of change of engine speed (dn) under steady-state operating conditions. During actual operation, the system continuously compares the deviation between the filtered actual signal and the model's prediction. If a persistent and significant deviation is detected, the system will adjust online and slowly. This changes the actual effective filter coefficients. This allows the filtering effect to converge towards the ideal state. (Learned) The value will be saved for use on the next power-on, thus enabling long-term parameter adaptation and experience accumulation.

[0092] Optionally, This method, based on statistical characteristics, involves operating condition calibration and offline mapping. It is primarily performed during engine bench or vehicle calibration. Raw signal data of the filter (dn) is collected under numerous different typical steady-state operating conditions (e.g., different speeds and load combinations). By analyzing the statistical characteristics of the signal (e.g., standard deviation) and conducting repeated tests, a filter that optimizes the filtering effect is calibrated for each operating condition. Then, the corresponding value for each operating condition point is derived. Value. During actual vehicle operation, the ECU retrieves the corresponding value from a table based on real-time operating conditions. value.

[0093] Furthermore, in The conditions are met continuously for a preset time. This indicates that the engine speed change rate is in a stable state (the speed change rate fluctuates little). The threshold coefficient is also included. In this example, we use 0.05. This example takes 0.1s.

[0094] (3) Intake density of fresh air entering the cylinder Filter coefficients The method for obtaining it is as follows:

[0095] (3.1) If both the engine speed and the rate of change of engine speed are in a steady state, then:

[0096] This example The calibration speed is 1000 rpm. The purpose of this setting is for normalization; at different engine speeds, no special calibration is needed, only calibration of the 4-cylinder engine and the engine at 1000 rpm. This eliminates the need for individual bench calibration tests at every RPM, significantly reducing the workload and time cost of engine calibration, thereby reducing calibration testing work. The default coefficient for the fresh air intake density entering the cylinder is 1; in this example, it is set to 0.02.

[0097] (3.2) In other cases, , The default coefficient for the fresh air intake density entering the cylinder is two; in this example, it is set to 0.02.

[0098] (4) Throttle opening Filter coefficients The method for obtaining it is as follows:

[0099] (4.1) If both the engine speed and the rate of change of engine speed are in a steady state, then:

[0100] This example The calibration speed is 1000 rpm. The purpose of this setting, as mentioned above, is for normalization processing. Throttle opening The default coefficient is 1; in this example, it is set to 0.02.

[0101] (4.2) In other cases, , Throttle opening The default coefficient is two; in this example, it is set to 0.02.

[0102] (5) Mixing valve opening Filter coefficients The method for obtaining it is as follows:

[0103] (5.1) If both the engine speed and the rate of change of engine speed are in a steady state, then:

[0104] This example The calibration speed is 1000 rpm. The purpose of this setting, as mentioned above, is for normalization processing. For the opening degree of the mixing valve The default coefficient is 1; in this example, it is set to 0.02.

[0105] (5.2) In other cases, , For the opening degree of the mixing valve The default coefficient is two; in this example, it is set to 0.02.

[0106] (6) EGR valve opening Filter coefficients The method for obtaining it is as follows:

[0107] (6.1) If both the engine speed and the rate of change of engine speed are in a steady state, then:

[0108] This example The calibration speed is 1000 rpm. The purpose of this setting, as mentioned above, is for normalization processing. EGR valve opening The default coefficient is 1; in this example, it is set to 0.02.

[0109] (6.2) In other cases, , EGR valve opening The default coefficient is two; in this example, it is set to 0.02.

[0110] (7) EGR valve inlet pressure Filter coefficients The method for obtaining it is as follows:

[0111] (7.1) If both the engine speed and the rate of change of engine speed are in a steady state, then:

[0112] This example The calibration speed is 1000 rpm. The purpose of this setting, as mentioned above, is for normalization processing. The default coefficient for the EGR valve inlet pressure is 1; in this example, it is set to 0.2.

[0113] (7.2) Other situations, The default inlet pressure coefficient for the EGR valve is two. Take 0.2. The filtering coefficient should not be less than the filtering coefficient of engine speed, engine speed change rate, fresh air intake density entering the cylinder, throttle opening, and mixing valve opening. This is because engine speed, engine speed change rate, fresh air intake density entering the cylinder, throttle opening, and mixing valve opening are used as conditions for checking EGR pressure. These conditions require stable operating conditions, so it is necessary to ensure that the EGR pressure is in a stable state. Therefore, the filtering coefficient should be relatively small. However, the filtering coefficient of the EGR valve inlet pressure should not be too small, otherwise it may lead to an incorrect evaluation of whether the EGR pressure is normal.

[0114] (8) EGR valve outlet pressure Filter coefficients The method for obtaining it is as follows:

[0115] (8.1) If both the engine speed and the rate of change of engine speed are in a steady state, then:

[0116] This example The calibration speed is 1000 rpm. The purpose of this setting, as mentioned above, is for normalization processing. The default coefficient for the EGR valve outlet pressure is 1; in this example, it is set to 0.2.

[0117] (8.2) Other situations, The default inlet pressure coefficient for the EGR valve is two. Take 0.2. The filtering coefficient should not be less than the engine speed, the rate of change of engine speed, the intake density of fresh air entering the cylinder, the throttle opening, and the mixing valve opening, for the same reasons as above.

[0118] It should be noted that the method for obtaining the calibration filter coefficient through bench testing is as follows: Under a preset reference operating condition (such as engine speed stable at 1000 rpm, specific load), the original signal of the target parameter (such as intake air density) is collected. By analyzing the noise characteristics and dynamic response requirements of the signal, the filter coefficient in the first-order low-pass filter formula is repeatedly adjusted and tested until the filtered signal can achieve the best balance between effectively filtering out high-frequency noise and not excessively delaying the real change. The filter coefficient finally determined at this time is the calibration filter coefficient under the reference speed.

[0119] Through the embodiments of the present invention, the calculation method for dynamically switching the filter coefficient based on the stable state of the engine speed parameters enables the filtering process to adapt to different engine operating states:

[0120] When the engine speed is stable, the calibrated filter coefficients obtained from bench tests are used for normalization calculations. This fully utilizes the precise data from bench tests to ensure that the filter coefficients achieve an optimal balance between signal smoothness and response delay at different engine speeds, effectively filtering out high-frequency noise and preserving true parameter changes. When the engine speed is unstable, self-learning coefficients are used to calculate the filter coefficients. These self-learning coefficients continuously optimize based on the actual engine operating conditions, avoiding the problem of poor filtering performance under dynamic conditions with fixed coefficients, while also ensuring the basic effectiveness of the filter.

[0121] Based on the above embodiments, the filtered values ​​of the EGR valve outlet pressure within a first preset number of sampling periods are preprocessed to obtain an outlet pressure array. Prior to this, the process further includes: using engine operating parameters and the filtered values ​​to determine the engine operating condition. Specifically, this includes: using the engine operating parameters and the difference between the engine operating parameters and the corresponding filtered values ​​to determine whether the engine meets the signal stability condition; responding to the engine signal stability condition, controlling the target EGR rate unchanged, and determining whether the engine meets the EGR valve gas stability condition; responding to the engine meeting the EGR valve gas stability condition, controlling the target EGR valve opening unchanged, and determining whether the engine meets the EGR valve opening stability condition; responding to the engine meeting the EGR valve opening stability condition, determining the engine operating condition as a steady-state condition.

[0122] The signal stability conditions specifically include:

[0123] (1) The engine is running.

[0124] (2) The engine speed is within a certain range, in this example it is between 600rpm and 5900rpm, and the engine speed enters a stable state after entering the EGR system pressure check.

[0125] (3) The intake density of fresh air entering the cylinder is within a certain range. In this example, it is between 200 mgpl and 3000 mgpl, and the intake density after the pressure check of the EGR system enters a stable state.

[0126] Specifically, in The conditions are met continuously for a preset time. This indicates that the intake air density is in a stable state (with minimal fluctuations). The threshold coefficient is also included. In this example, we use 0.05. This example takes 0.1s.

[0127] (4) Throttle opening It has entered a stable state.

[0128] Specifically, in The conditions are met continuously for a preset time. This indicates that the throttle opening is in a stable state (throttle fluctuation is small). The threshold coefficient is also mentioned. In this example, the value is 0.01. This example takes 0.1s.

[0129] (5) The boost control closed loop state remains unchanged. That is, if the boost control closed loop state has been entered, the boost control closed loop state must be maintained; if the closed loop state has not been entered, the boost control closed loop state should not be entered.

[0130] (6) Target air-fuel ratio fluctuation, that is, the difference between the target air-fuel ratios of two adjacent sampling periods, is within a certain range, and in this example it is taken as ±0.1.

[0131] (7) The difference between the target air-fuel ratio and the actual air-fuel ratio fluctuates, that is, the difference between the target air-fuel ratio and the actual air-fuel ratio in two adjacent sampling periods. Within a certain range, this example takes ±0.1.

[0132] (8) The actual air-fuel ratio fluctuation, that is, the difference between the actual air-fuel ratios of two adjacent sampling periods, is within a certain range. In this example, it is taken as ±0.1.

[0133] (9) The engine coolant temperature is within a certain range (0℃ to 100℃ in this example), and the engine coolant temperature fluctuation after entering the EGR system pressure check is small, that is, the difference between the engine coolant temperatures of two adjacent sampling periods is small. In this example, ±2℃ is taken.

[0134] (10) The intake temperature is within a certain range (30℃ to 80℃ in this example), and the intake temperature fluctuation after entering the EGR system pressure check is small, that is, the difference between the intake temperatures of two adjacent sampling cycles is small. In this example, it is ±1.5℃.

[0135] (11) Ignition angle efficiency fluctuation, that is, the difference between the ignition angle efficiency of two adjacent sampling periods is small. In this example, it is ±0.1.

[0136] (12) No detonation occurred and no premature combustion occurred.

[0137] (13) The engine did not experience fuel cut-off.

[0138] (14) Both the oxygen sensor before the catalyst and the oxygen sensor after the catalyst have been activated by heating.

[0139] (15) Atmospheric pressure fluctuation, that is, the difference in atmospheric pressure between two adjacent sampling periods is small. In this example, it is ±0.5 kPa.

[0140] (16) No fire malfunction occurred.

[0141] (17) No EGR system pressure signal fault was detected during this vehicle driving cycle.

[0142] After all the above conditions are met for more than the preset signal stability judgment time (5 seconds in this example), the EGR valve gas stability condition is checked. The EGR valve gas stability condition specifically includes:

[0143] (1) Mixing valve opening Reaching a stable state:

[0144] exist The conditions are met continuously for a preset time. This indicates that the mixing valve opening is in a stable state (the mixing valve fluctuation is small). The threshold coefficient is also mentioned. In this example, the value is 0.01. This example takes 0.1s.

[0145] (2) Actively control the target EGR rate Fixed and unchanging.

[0146] (3) The EGR valve opening is in a stable state:

[0147] exist The conditions are met continuously for a preset time. This indicates that the EGR valve opening is in a stable state (the EGR valve fluctuation is small). The threshold coefficient is also mentioned. In this example, the value is 0.01. This example takes 0.1s.

[0148] (4) The inlet pressure fluctuation of the EGR valve is small. That is, it satisfies:

[0149] exist The conditions are met continuously for a preset time. This indicates that the EGR valve inlet pressure is in a stable state. The threshold coefficient is also mentioned. In this example, the value is 0.01. This example takes 0.05s.

[0150] (5) The EGR valve inlet temperature fluctuates, that is, the difference between the EGR valve inlet temperature in two adjacent sampling periods is small. In this example, it is ±3℃.

[0151] (6) No EGR valve inlet pressure sensor circuit failure occurred, including any circuit failure such as open circuit or short circuit.

[0152] (7) No EGR valve outlet pressure sensor circuit failure occurred, including any circuit failure such as open circuit or short circuit.

[0153] After all the above EGR valve gas stability conditions have been met for more than the preset signal stability judgment time (0.5s in this example), the EGR valve opening stability condition is checked. The EGR valve opening stability conditions specifically include:

[0154] The EGR valve opening stability conditions specifically include:

[0155] After all the gas stability conditions of the EGR valve are met, the average value within t1 (i.e., the first preset time period) is read. t1 time Where C1 is 0.2s, This represents the average engine speed after filtering during the minimum process. The target EGR valve opening is forcibly fixed at [value]. The system remains fixed and is maintained at t2 (i.e., the second preset time). If the EGR valve opening is not stable within t2 (the determination of whether the EGR valve opening is stable is as described above), the diagnosis is terminated. If the EGR valve opening is stable within t2, the EGR valve opening stability condition is met.

[0156] The t2 value precisely covers the gas flow delay time, ensuring sufficient time for obtaining reliable signal data to verify the opening stability, avoiding misjudgments due to insufficient time, while also preventing excessive time from increasing the computational load on the engine control system. The t2 value is obtained as follows:

[0157] (1) If the EGR valve is closed, then t2 is the time it takes for fresh air to flow from the outlet of the mixing valve to the inlet of the turbocharger. It is obtained by bench calibration. Bench calibration can fix the engine speed and the intake density of fresh air entering the cylinder, and close the EGR valve. The average time it takes for fresh air to flow from the outlet of the mixing valve to the inlet of the turbocharger is obtained by debugging various data sampling.

[0158] (2) If the EGR valve is not closed, then t2 is the time it takes for the exhaust gas to flow from the outlet of the GPF gasoline particulate filter to the outlet of the mixing valve. It is obtained by bench calibration. Bench calibration can fix the engine speed and the intake density of fresh air entering the cylinder, as well as fix different EGR valve openings. The average time it takes for the exhaust gas to flow from the GPF outlet to the outlet of the mixing valve is obtained by debugging various data sampling.

[0159] Through the embodiments of the present invention Figure 3 A flowchart of another anomaly diagnosis method applied to an engine system provided in this disclosure embodiment is shown below. Figure 3As shown, a three-tiered judgment system—signal stability condition, EGR valve gas stability condition, and EGR valve opening stability condition—gradually focuses on the core operating parameters of the EGR system, narrowing down from overall engine operating condition stability to the local operating state stability of the EGR valve. This ensures the rigor of the steady-state condition judgment, allowing the final judgment to accurately reflect the stable operating state of the EGR system. The signal stability condition covers 17 core parameters, including engine speed, intake air density, valve opening, air-fuel ratio, temperature, pressure, and fault status. Comprehensive verification is performed from multiple dimensions, including engine operating status, parameter range, parameter fluctuations, and fault diagnosis, ensuring the engine is in a stable operating state. In the second and third levels of condition judgment, the target EGR rate and target EGR valve opening are actively and strictly controlled to remain constant, eliminating normal fluctuations in the outlet pressure signal caused by the EGR system actively changing the valve opening to adjust the EGR rate. Existing technologies do not strictly control the EGR rate and valve opening, leading to pressure signal fluctuations during the system's active adjustment process being included in the verification scope, which can easily cause misjudgments.

[0160] The EGR outlet pressure stability check can only be performed after all signal stability conditions, EGR valve gas stability conditions, and EGR valve opening stability conditions are simultaneously met. If any of these conditions are not met, or if any of them suddenly become unmet during the EGR outlet pressure stability check, the EGR outlet pressure stability check will be stopped, and this will be indicated as a fault not being detected.

[0161] Based on the above embodiments, the filtered values ​​of the EGR valve outlet pressure within a first preset number of sampling periods are preprocessed to obtain an outlet pressure array, including: reading the maximum and minimum values ​​of the filtered values ​​of the EGR valve outlet pressure within a first preset number of sampling periods to obtain a first maximum value array and a first minimum value array; removing the first second preset number of elements from the first maximum value array and the first minimum value array, removing the maximum value and the corresponding minimum value that are 0, to obtain a second maximum value array and a second minimum value array; dividing the second maximum value array and the second minimum value array according to a third preset number to obtain a third preset number of maximum value intervals and a third preset number of minimum value intervals, calculating the average value of each interval, removing the average value of the maximum value and the corresponding average value of the minimum value that are 0, to obtain a final maximum value array and a final minimum value array; and averaging the corresponding elements of the final maximum value array and the final minimum value array to obtain a mean value array.

[0162] In this embodiment, the filtered EGR outlet pressure is read within the sampling period. The maximum and minimum values ​​are recorded as [pmax0, pmax1, ...] and [pmin0, pmin1, ...], respectively, where pmax0 is the first sampling period after all minimum values ​​and the EGR valve gas stability condition and EGR valve opening stability condition are met (sampling period interval). The maximum value of the EGR outlet pressure read, pmax1 is the second sampling period after all minimum values ​​and the EGR valve gas stability condition and EGR valve opening stability condition are met (sampling period interval). The maximum value of the EGR outlet pressure read is used, and so on. Where pmin0 is the first sampling period after all minimum values ​​and the EGR valve gas stability condition and EGR valve opening stability condition are met (sampling period interval). The minimum value of the EGR outlet pressure read, pmin1 is the second sampling period after all minimum values ​​and the EGR valve gas stability condition and EGR valve opening stability condition are met (sampling period interval). The minimum value of the EGR outlet pressure read, and so on.

[0163] First, the maximum and minimum values ​​of the first M (second preset number) sampling periods need to be removed to avoid signal instability in the early stages of stable inspection conditions, which could affect the accuracy of pressure signal inspection. Table 1 schematically shows the lookup table for M (first calibration table). The first row represents the average value of the engine speed filter value under stable signal conditions. The method for obtaining M is to look up the table and finally take the larger value, but not exceeding the maximum and minimum values ​​in the table. That is, if the average value of the engine speed filter value in the minimum value is greater than 1000 rpm but less than 1400 rpm, then M is 5; if the average value of the engine speed filter value in the minimum value is not greater than 600 rpm, then M is 2; if the average value of the engine speed filter value in the minimum value is greater than 5700 rpm, then M is 12.

[0164] Table 1

[0165]

[0166] After removing the maximum and minimum values ​​from M sampling periods, the average of the maximum and minimum values ​​in M1 is calculated according to the interval division M1 (50 in this example), forming a maximum value array [pmaxAvg0, pmaxAvg1,…] and a minimum value array [pminAvg0, pmaxAvg1,…]. In particular, if any element pmaxAvgQ (Q=0,1,2,3…) in the maximum value array or any original pmaxAvgR (R=0,1,2,3…) in the maximum value array is equal to 0, then the maximum and minimum values ​​corresponding to element Q, as well as the maximum and minimum values ​​corresponding to element R, are removed, and a new array is formed. The stability of the outlet pressure signal is checked on the new array.

[0167] Through embodiments of the present invention, by removing the first M initial unstable elements and invalid elements with values ​​of 0, the interference of abnormal data on the array is eliminated, ensuring the validity and reliability of the array data. Dividing the array into intervals according to M1 and calculating the interval average effectively smooths out random small fluctuations in the pressure signal. After smoothing, the array data can be more focused on significant fluctuations caused by faults. Simultaneously, three types of outlet pressure arrays—maximum value array, minimum value array, and mean value array—are constructed to reflect the upper limit fluctuation, lower limit fluctuation, and average level fluctuation of the pressure signal, respectively.

[0168] Based on the above embodiments, according to the stability of the rotational speed change rate, the number of times the difference between adjacent elements in the outlet pressure array is greater than a dynamic value threshold is used to determine whether the outlet pressure signal has a fault. This includes: using the rotational speed change rate and its filtered value to determine whether the rotational speed change rate is stable within a third preset time period; if the rotational speed change rate is unstable within the third preset time period, the determination is made based on the mean array in the outlet pressure array, counting the number of times the absolute value of the difference between adjacent elements in the mean array is greater than a first dynamic threshold, and determining that the outlet pressure signal has a fault when the first count exceeds a first fault counting threshold; if the rotational speed change rate is stable within the third preset time period, the determination is made based on the maximum value array and the minimum value array in the outlet pressure array, counting the number of times the absolute value of the difference between adjacent elements in the maximum value array is greater than a second dynamic threshold, the number of times the absolute value of the difference between adjacent elements in the minimum value array is greater than a third dynamic threshold, and the number of times the absolute value of the difference between the corresponding elements of the maximum and minimum value arrays is greater than a fourth dynamic threshold, and determining that the outlet pressure signal has a fault when the second, third, or fourth count exceeds a second fault counting threshold.

[0169] The first dynamic threshold, the second dynamic threshold, the third dynamic threshold, and the fourth dynamic threshold are determined at least based on the target EGR rate, the filtered value of the rotational speed, the target EGR valve opening, the EGR valve inlet temperature, the EGR valve inlet pressure, and the filtered value of the EGR valve inlet pressure; the first fault count threshold and the second fault count threshold are determined at least based on the ratio of the fresh air intake flow rate entering the cylinder to the pressure at the outlet and inlet of the mixing valve.

[0170] Based on the above embodiments, the calculation methods for the first dynamic threshold, the second dynamic threshold, the third dynamic threshold, and the fourth dynamic threshold include: obtaining the first dynamic threshold based on a first preset default threshold, the minimum absolute value of the difference between adjacent elements in the mean array, a first correction factor, and a second correction factor; obtaining the second dynamic threshold based on the second preset default threshold, the minimum absolute value of the difference between adjacent elements in the maximum value array, a third correction factor, and a fourth correction factor; obtaining the third dynamic threshold based on the second preset default threshold, the minimum absolute value of the difference between adjacent elements in the minimum value array, a third correction factor, and a fourth correction factor; and obtaining the third dynamic threshold based on the second preset default threshold, the minimum absolute value of the difference between corresponding elements in the maximum and minimum value arrays, a third correction factor, and a fourth correction factor. The fourth dynamic threshold is obtained by combining the first and fourth correction factors. The first correction factor is calculated using a first preset value, the target EGR rate, and a calibration value. The second correction factor is calculated using a second preset value, the EGR valve inlet temperature, the EGR valve inlet pressure, and a filtered value of the EGR valve inlet pressure. The third correction factor is calculated using a third preset value, the target EGR rate, and a calibration value. The fourth correction factor is calculated using a fourth preset value, the EGR valve inlet temperature, the EGR valve inlet pressure, and a filtered value of the EGR valve inlet pressure. The calibration value is obtained by querying a preset second calibration table. The second calibration table stores the corresponding calibration values, indexed by the filtered value of the rotational speed and the target EGR valve opening.

[0171] (1) If the rate of change of engine speed is not in a stable state. Take the maximum value and minimum value of each element position of the maximum value array [pmaxAvg0,pmaxAvg1,...] and the minimum value array [pminAvg0,pmaxAvg1,...] and average them again to form [pAvg0,pAvg1,...].

[0172] The element i = 0, 1, 2, 3… If the above formula is satisfied more than a preset number of times - CNT1, it indicates that the stability of the outlet pressure signal has been checked and a fault has been detected; otherwise, it indicates that no fault has occurred.

[0173]

[0174] The default threshold is set to 0.1 in this example. The target EGR rate is the gas stability condition for the EGR valve. The average value of the target EGR valve opening over time t1 is given by the EGR valve opening stability condition. This represents the average value of the filtered engine speed under stable signal conditions. This represents the average inlet temperature of the EGR valve under stable signal conditions. The default EGR valve inlet temperature is 550℃ in this example. The default speed is 1000 rpm in this example. The actual EGR valve inlet pressure within the M1 sampling interval corresponding to element i; The filtered value of the actual EGR valve inlet pressure within the M1 sampling interval corresponding to element i.

[0175] It is the first correction factor.

[0176] This is the second correction factor.

[0177] For element i, within the M1 sampling interval Maximum value.

[0178] , The values ​​were 0.03 and 0.045 respectively, in different... Rotation speed The EGR valve opening is obtained based on the fitting data from both faulty and non-faulty pressure sensors. (Preset)

[0179] Where the correction coefficient and , Based on the results determined by faulty and non-faulty pressure sensors, and benchmarked against both faulty and non-faulty pressure sensors, the three-standard-deviation principle is used to determine the... , , and correction factor, where , The values ​​are 0.03 and 0.045 respectively.

[0180] (2) If the rate of change of engine speed is in a steady state

[0181] The maximum value array [pmaxAvg0, pmaxAvg1, ...] and the minimum value array [pminAvg0, pmaxAvg1, ...] are if the following conditions are met:

[0182] The number of times i=0,1,2,3… exceeds the preset number of times CNT2.

[0183] or, The number of times i=0,1,2,3… exceeds the preset number of times CNT2.

[0184] or, The number of times i=0,1,2,3… exceeds the preset number of times CNT2.

[0185]

[0186] The default threshold is set to 0.1 in this example. The target EGR rate is the gas stability condition for the EGR valve. The average value of the target EGR valve opening over time t1 is given by the EGR valve opening stability condition. This represents the average value of the filtered engine speed under stable signal conditions. This represents the average inlet temperature of the EGR valve under stable signal conditions. The default EGR valve inlet temperature is 550℃ in this example. The default speed is 1000 rpm in this example. The actual EGR valve inlet pressure within the M1 sampling interval corresponding to element i; The filtered value of the actual EGR valve inlet pressure within the M1 sampling interval corresponding to element i; For element i, within the M1 sampling interval Maximum value.

[0187] Where the correction coefficient and , Based on the results determined by faulty and non-faulty pressure sensors, and benchmarked against both faulty and non-faulty pressure sensors, the three-standard-deviation principle is used to determine the... , , and correction factor, where , The values ​​are 0.025 and 0.042 respectively.

[0188] Through embodiments of this invention, differentiated pressure signal stability diagnosis is performed for two states: stable and unstable speed change rate. When the speed change rate is unstable, a single-dimensional judgment using a mean array is employed, closely reflecting the characteristics of average pressure signal fluctuations under slight dynamic engine operating conditions. When the speed change rate is stable, a multi-dimensional judgment using maximum and minimum value arrays is employed, accurately capturing abnormal fluctuations in pressure signal extreme values ​​under strictly steady-state operating conditions. This achieves high adaptability for pressure signal diagnosis under different engine operating conditions, enabling more sensitive and accurate identification of small and continuous abnormal fluctuations in the pressure signal. The dynamic threshold is adapted to the actual operating conditions of the engine and EGR system, avoiding judgment deviations caused by thresholds. Furthermore, the calibration value is obtained by querying a calibration table indexed by the speed filter value and the target EGR valve opening, allowing the correction factor value to better reflect the system operating characteristics under different speeds and different EGR valve openings.

[0189] Based on the above embodiments, the calculation method for the first fault count threshold and the second fault count includes: obtaining a first ratio of the absolute value of the average fresh air intake flow rate entering the cylinder under stable signal conditions to a preset flow rate; obtaining a second ratio of the average value of the mixing valve outlet pressure to the average value of the mixing valve inlet pressure under stable signal conditions; the calculation steps for the first fault count threshold are: obtaining a first base value by inputting the first ratio into a third calibration table or a fourth calibration table; obtaining a second base value by inputting the second ratio into a fifth calibration table or a sixth calibration table; multiplying the first base value and the second base value and rounding to determine the first fault count threshold; wherein, the third calibration table is used when the EGR valve is closed, and stores the corresponding first base value with the first ratio as an index; the fifth calibration table is used when the EGR valve is closed, and stores the corresponding second base value with the second ratio as an index; the fourth calibration table is used when the EGR valve is not closed. The first calibration table stores the corresponding first basic value using the first ratio as an index; the sixth calibration table, used when the EGR valve is not closed, stores the corresponding second basic value using the second ratio as an index; the calculation steps for the second fault count threshold are as follows: by inputting the first ratio into the seventh or eighth calibration table, a third basic value is obtained; by inputting the second ratio into the ninth or tenth calibration table, a fourth basic value is obtained; the third basic value and the fourth basic value are multiplied together and rounded to determine the second fault count threshold; wherein, the seventh calibration table, used when the EGR valve is closed, stores the corresponding third basic value using the first ratio as an index; the ninth calibration table, used when the EGR valve is closed, stores the corresponding fourth basic value using the second ratio as an index; the eighth calibration table, used when the EGR valve is not closed, stores the corresponding third basic value using the first ratio as an index; the tenth calibration table, used when the EGR valve is not closed, stores the corresponding fourth basic value using the second ratio as an index.

[0190] The first fault count threshold, CNT1, is obtained as follows:

[0191] (1) If the EGR valve is closed, the absolute value of the average fresh air intake flow rate into the cylinder is based on the signal stability condition. With default traffic (This example uses a ratio of 10 g / s) And the correction factor determined by the ratio of the average outlet pressure of the mixing valve to the average inlet pressure of the mixing valve under stable signal conditions. The decision is made jointly, whereby the average outlet pressure of the mixing valve under signal stability conditions represents the outlet pressure of the mixing valve obtained when checking whether the signal stability conditions are met. Once the signal stability conditions are verified, the average outlet pressure of the mixing valve during the verification process is calculated and stored, i.e., CNT1 = V1. The values ​​are rounded to the nearest integer. The larger the absolute value of the intake airflow, the greater the potential flow disturbance in the exhaust system. Therefore, the larger the threshold coefficient CNT1 = V1, the more likely the flow disturbance will have to cause problems. The calibration tables are shown in Tables 2 and 3.

[0192] Table 2

[0193]

[0194] The higher the pressure ratio of the mixing valve, the worse the throttling effect of the mixing valve, and the greater the gas flow disturbance may be. This can easily cause disturbances in the EGR valve outlet pressure, leading to a decrease in the accuracy of signal verification. To avoid such problems, it is necessary to increase the threshold number of times.

[0195] Table 3

[0196]

[0197] (2) If the EGR valve is not closed, the absolute value of the average fresh air intake flow rate into the cylinder is based on the signal stability condition. With default traffic (In this example, 10 g / s is used) The correction factor is determined by the ratio of the average outlet pressure of the mixing valve to the average inlet pressure of the mixing valve under stable signal conditions. It is jointly determined that CNT1=V2 is The result is obtained by rounding to the nearest integer, CNT1 = V2 (V2 is not less than V1). The larger the absolute value of the intake airflow, the greater the potential flow disturbance in the exhaust system; therefore, the larger the threshold coefficient 2 should be to avoid the impact of flow disturbance. The calibration tables are shown in Tables 4 and 5.

[0198] Table 4

[0199]

[0200] The higher the pressure ratio of the mixing valve, the worse the throttling effect of the mixing valve, and the greater the gas flow disturbance may be. This can easily cause disturbances in the EGR valve outlet pressure, leading to a decrease in the accuracy of signal verification. To avoid such problems, it is necessary to increase the threshold number of times.

[0201] Table 5

[0202]

[0203] The second fault count threshold CNT2 is obtained as follows:

[0204] (1) If the EGR valve is closed, the absolute value of the average fresh air intake flow rate into the cylinder is based on the signal stability condition. With default traffic (This example uses a ratio of 10 g / s) And the correction factor determined by the ratio of the average outlet pressure of the mixing valve to the average inlet pressure of the mixing valve under stable signal conditions. It is jointly determined that CNT2 = V3 (V3 is not greater than V1). The values ​​are rounded to the nearest integer. The larger the absolute value of the intake airflow, the greater the potential flow disturbance in the exhaust system. Therefore, the larger the threshold coefficient (CNT2 = V3) should be to avoid the impact of flow disturbance. The calibration tables are shown in Tables 6 and 7.

[0205] Table 6

[0206]

[0207] The higher the pressure ratio of the mixing valve, the worse the throttling effect of the mixing valve, and the greater the gas flow disturbance may be. This can easily cause disturbances in the EGR valve outlet pressure, leading to a decrease in the accuracy of signal verification. To avoid such problems, it is necessary to increase the threshold number of times.

[0208] Table 7

[0209]

[0210] (2) If the EGR valve is not closed, the absolute value of the average fresh air intake flow rate into the cylinder is based on the signal stability condition. With default traffic (In this example, 10 g / s is used) The correction factor is determined by the ratio of the average outlet pressure of the mixing valve to the average inlet pressure of the mixing valve under stable signal conditions. It is jointly determined that CNT2=V4 is The result is obtained by rounding to the nearest integer, CNT2 = V4 (V4 is not less than V3). The larger the absolute value of the intake airflow, the greater the potential flow disturbance in the exhaust system; therefore, the larger the threshold coefficient 2 should be to avoid the impact of flow disturbance. The calibration tables are shown in Tables 8 and 9.

[0211] Table 8

[0212]

[0213] The higher the pressure ratio of the mixing valve, the worse the throttling effect of the mixing valve, and the greater the gas flow disturbance may be. This can easily cause disturbances in the EGR valve outlet pressure, leading to a decrease in the accuracy of signal verification. To avoid such problems, it is necessary to increase the threshold number of times.

[0214] Table 9

[0215]

[0216] If the signal stability condition is not met when the EGR valve switches between closed and open states, then the pressure signal verification will be terminated.

[0217] Through the embodiments of this disclosure, the fault counting threshold can simultaneously respond to gas flow disturbances caused by changes in engine intake airflow and the throttling effect of the mixing valve. The higher the intake airflow and the higher the mixing valve pressure ratio, the higher the threshold will be. This effectively avoids the problem of normal pressure signal fluctuations caused by exhaust system flow disturbances and poor mixing valve throttling effect being misjudged as faults, and achieves dynamic adaptive optimization of the fault counting threshold. At the same time, dedicated calibration tables are configured for the two states of EGR valve closed and open, so that the threshold calculation can accurately match the gas flow characteristics of the EGR system under different operating conditions. When the EGR valve is not closed, the threshold is not less than that in the closed state, which is close to the actual operating condition where the pressure signal fluctuates more during exhaust gas recirculation.

[0218] Figure 4 A structural block diagram of an abnormality diagnosis system for an engine system provided in an embodiment of the present invention is shown below. Figure 4 As shown, a second aspect of the present invention provides an anomaly diagnosis system for an engine system, which can be used to implement the above-described anomaly diagnosis method for an engine system, including:

[0219] The parameter filtering module is used to perform first-order low-pass filtering on each engine operating parameter using the corresponding filtering coefficients to obtain the corresponding filtered value. The engine operating parameters include at least engine speed parameters and engine-related parameters. The filtering coefficients for each engine-related parameter are determined based on the stability of the engine speed parameters. The engine speed parameters include engine speed and rate of change of engine speed. The engine-related parameters include at least the EGR valve outlet pressure.

[0220] The operating condition judgment module is used to determine that the engine operating condition is a steady state by using engine operating parameters and filter values. Then, it preprocesses the filter values ​​of the EGR valve outlet pressure within a first preset number of sampling periods to obtain an outlet pressure array. The outlet pressure array includes at least one of a maximum value array, a minimum value array, and a mean value array.

[0221] The stability check module is used to determine whether the outlet pressure signal is faulty by measuring the number of times the difference between adjacent elements of the outlet pressure array is greater than the dynamic value threshold, based on the stability of the speed change rate. The dynamic value threshold is determined based on the engine operating parameters.

[0222] Based on the same inventive concept, embodiments of the present invention also provide an electronic device. Figure 5 This is a structural block diagram of an electronic device provided in an embodiment of the present invention. Figure 5 As shown, an embodiment of the present invention provides an electronic device including: one or more processors 101, a memory 102, and one or more I / O interfaces 103. The memory 102 stores one or more programs, which, when executed by the one or more processors, cause the one or more processors to implement any of the abnormal diagnosis methods applied to an engine system as described in the above embodiments; the one or more I / O interfaces 103 are connected between the processor and the memory, configured to enable information interaction between the processor and the memory.

[0223] The processor 101 is a device with data processing capabilities, including but not limited to a central processing unit (CPU); the memory 102 is a device with data storage capabilities, including but not limited to random access memory (RAM, more specifically SDRAM, DDR, etc.), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), and flash memory (FLASH); the I / O interface (read / write interface) 103 is connected between the processor 101 and the memory 102, and can realize information interaction between the processor 101 and the memory 102, including but not limited to a data bus (Bus).

[0224] In some embodiments, the processor 101, memory 102, and I / O interface 103 are interconnected via bus 104, and thus connected to other components of the computing device.

[0225] In some embodiments, the one or more processors 101 include a field-programmable gate array.

[0226] This invention also provides a computer-readable medium. The computer-readable medium stores a computer program, which, when executed by a processor, implements the steps of any of the anomaly diagnosis methods applied to an engine system as described in the above embodiments. The computer-readable storage medium may be volatile or non-volatile.

[0227] This invention also provides a computer program product, including computer-readable code, or a non-volatile computer-readable storage medium carrying computer-readable code. When the computer-readable code is run in the processor of an electronic device, the processor in the electronic device executes the above-described anomaly diagnosis method applied to an engine system.

[0228] Those skilled in the art will understand that all or some of the steps, systems, and apparatuses disclosed above, and their functional modules / units, can be implemented as software, firmware, hardware, or suitable combinations thereof. In hardware implementations, the division between functional modules / units mentioned above does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed collaboratively by several physical components. Some or all physical components may be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit (ASIC). Such software can be distributed on a computer-readable storage medium, which may include computer storage media (or non-transitory media) and communication media (or transient media).

[0229] As is known to those skilled in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information, such as computer-readable program instructions, data structures, program modules, or other data. Computer storage media includes, but is not limited to, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), static random access memory (SRAM), flash memory or other memory technologies, portable compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and is accessible to a computer. Furthermore, it is known to those skilled in the art that communication media typically contain computer-readable program instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0230] The computer-readable program instructions described herein can be downloaded from computer-readable storage media to various computing / processing devices, or downloaded via a network, such as the Internet, local area network, wide area network, and / or wireless network, to an external computer or external storage device. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards them to the computer-readable storage media in the respective computing / processing device.

[0231] The computer program instructions used to perform the operations of this invention may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, etc., and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The computer-readable program instructions may be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, electronic circuitry, such as programmable logic circuitry, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), is personalized by utilizing state information from the computer-readable program instructions. This electronic circuitry can execute the computer-readable program instructions to implement various aspects of the invention.

[0232] The computer program product described herein can be implemented specifically through hardware, software, or a combination thereof. In one alternative embodiment, the computer program product is specifically embodied in a computer storage medium; in another alternative embodiment, the computer program product is specifically embodied in a software product, such as a software development kit (SDK), etc.

[0233] Various aspects of the present invention are described herein with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer-readable program instructions.

[0234] These computer-readable program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to produce a machine such that, when executed by the processor of the computer or other programmable data processing apparatus, they create means for implementing the functions / actions specified in one or more blocks of the flowchart and / or block diagram. These computer-readable program instructions can also be stored in a computer-readable storage medium that causes a computer, programmable data processing apparatus, and / or other device to operate in a particular manner; thus, the computer-readable medium storing the instructions comprises an article of manufacture that includes instructions for implementing aspects of the functions / actions specified in one or more blocks of the flowchart and / or block diagram.

[0235] Computer-readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable data processing apparatus, or other device to produce a computer-implemented process, thereby causing the instructions executed on the computer, other programmable data processing apparatus, or other device to perform the functions / actions specified in one or more boxes of a flowchart and / or block diagram.

[0236] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of an instruction, which contains one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions marked in the blocks may occur in a different order than those shown in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, may be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0237] Example embodiments have been disclosed herein, and while specific terminology has been used, it is for illustrative purposes only and should be construed as such, and is not intended to be limiting. In some instances, it will be apparent to those skilled in the art that features, characteristics, and / or elements described in conjunction with particular embodiments may be used alone, or in combination with features, characteristics, and / or elements described in conjunction with other embodiments, unless otherwise expressly indicated. Therefore, those skilled in the art will understand that various changes in form and detail may be made without departing from the scope of the invention as set forth in the appended claims.

Claims

1. A method for diagnosing anomalies in an engine system, characterized in that, include: For each engine operating parameter, a first-order low-pass filter is performed using the corresponding filter coefficient to obtain the corresponding filter value; wherein, the engine operating parameters include at least engine speed parameters and engine-related parameters; the filter coefficient corresponding to each engine-related parameter is determined based on the stability of the engine speed parameters; the engine speed parameters include engine speed and rate of change of engine speed; the engine-related parameters include at least the EGR valve outlet pressure; In response to determining that the engine operating condition is a steady-state condition using the engine operating parameters and the filtered value, the filtered value of the EGR valve outlet pressure within a first preset number of sampling periods is preprocessed to obtain an outlet pressure array; the outlet pressure array includes at least one of a maximum value array, a minimum value array, and a mean value array; Based on the stability of the speed change rate, the number of times the difference between adjacent elements of the outlet pressure array exceeds a dynamic value threshold is used to determine whether the outlet pressure signal is faulty; the dynamic value threshold is determined based on the engine operating parameters.

2. The method according to claim 1, wherein, The engine-related parameters include at least one of the following: intake air density into the cylinder, throttle opening, mixing valve opening, EGR valve opening, EGR valve inlet pressure, and EGR valve outlet pressure; the calculation method for the filter coefficients corresponding to the engine-related parameters includes: Determine whether the engine speed parameters are in a stable state; If the engine speed parameters are stable, the current filter coefficient is calculated based on the preset calibration filter coefficient and the engine speed; the calibration filter coefficient is obtained by bench testing an engine at the preset speed. If the engine speed parameters are unstable, the current filter coefficient is calculated based on the preset self-learning coefficient.

3. The method according to claim 1, wherein, The process of preprocessing the filtered values ​​of the EGR valve outlet pressure within a first preset number of sampling periods to obtain an outlet pressure array includes, prior to: Using the engine operating parameters and the filter value, the engine operating condition is determined, specifically including: By using engine operating parameters and the difference between engine operating parameters and corresponding filter values, it can be determined whether the engine meets the signal stability conditions. In response to the engine signal stabilization condition, the target EGR rate remains unchanged, and it is determined whether the engine meets the EGR valve gas stabilization condition. In response to the engine meeting the EGR valve gas stability condition, the control target EGR valve opening remains unchanged, and it is determined whether the engine meets the EGR valve opening stability condition. If the engine meets the EGR valve opening stability condition, then the engine operating condition is determined to be a steady-state condition.

4. The method according to claim 3, wherein, The control target EGR valve opening is kept constant. The determination of whether the engine meets the EGR valve opening stability condition includes: Read the first average value of the target EGR valve opening within a first preset time period; The target EGR valve opening is kept constant at the first average value. Using the EGR valve opening degree and its filtered value, determine whether the EGR valve opening degree is stable within the second preset time period; If so, the engine is determined to meet the EGR valve opening stability condition; If not, the engine is determined not to meet the EGR valve opening stability condition, and the outlet pressure signal stability check is terminated.

5. The method according to claim 4, wherein, The method for obtaining the second preset time includes: In response to the EGR valve opening being 0, the second preset time is the time required for the calibrated fresh air to flow from the mixing valve outlet to the booster inlet; In response to an EGR valve opening greater than 0, the second preset time is the time required for exhaust gas to flow from the gasoline particulate filter outlet to the mixing valve outlet at the current EGR valve opening, as determined by calibration.

6. The method according to claim 1, wherein, The filtered values ​​of the EGR valve outlet pressure within a first preset number of sampling periods are preprocessed to obtain an outlet pressure array, including: Read the maximum and minimum values ​​of the filtered values ​​of the EGR valve outlet pressure within a first preset number of sampling periods to obtain a first maximum value array and a first minimum value array; Remove the first second preset number of elements from the first maximum value array and the first minimum value array, and remove the maximum value and the corresponding minimum value that are 0 to obtain the second maximum value array and the second minimum value array; Divide the data into a second maximum value array and a second minimum value array according to the third preset quantity, obtain the maximum value interval and the minimum value interval of the third preset quantity, calculate the average value of each interval, remove the average value of the maximum value and the corresponding average value of the minimum value that are 0, and obtain the final maximum value array and the final minimum value array. The mean array is obtained by averaging the corresponding elements of the final maximum value array and the final minimum value array.

7. The method according to claim 6, wherein, The method for obtaining the second preset quantity includes: Based on the filtered value of the rotational speed, the second preset quantity is obtained by querying the first calibration table; the first calibration table records the mapping relationship between the range of filtered values ​​of rotational speed and the second preset quantity.

8. The method according to claim 1, wherein, The step of determining whether the outlet pressure signal is faulty based on the stability of the rotational speed change rate and the number of times the difference between adjacent elements of the outlet pressure array exceeds a dynamic numerical threshold includes: Using the rate of change of rotational speed and the filtered value of the rate of change of rotational speed, it is determined whether the rate of change of rotational speed is stable within a third preset time period; If the rotational speed change rate is unstable within a third preset time period, a judgment is made based on the mean array in the outlet pressure array. The number of times the absolute value of the difference between adjacent elements in the mean array is greater than the first dynamic threshold is counted. When the first number exceeds the first fault count threshold, the outlet pressure signal is determined to be faulty. If the rotational speed change rate is stable within a third preset time period, then a judgment is made based on the maximum value array and minimum value array in the outlet pressure array. The number of times the absolute value of the difference between adjacent elements in the maximum value array is greater than the second dynamic threshold, the number of times the absolute value of the difference between adjacent elements in the minimum value array is greater than the third dynamic threshold, and the number of times the absolute value of the difference between the corresponding elements of the maximum and minimum value arrays is greater than the fourth dynamic threshold are counted. When the second, third, or fourth count exceeds the second fault count threshold, it is determined that the outlet pressure signal has a fault. The first dynamic threshold, the second dynamic threshold, the third dynamic threshold, and the fourth dynamic threshold are determined at least based on the target EGR rate, the filtered value of the rotational speed, the target EGR valve opening, the EGR valve inlet temperature, the EGR valve inlet pressure, and the filtered value of the EGR valve inlet pressure. The first fault count threshold and the second fault count threshold are determined at least based on the ratio of the fresh air intake flow rate into the cylinder to the pressure at the outlet and inlet of the mixing valve.

9. The method according to claim 8, wherein, The calculation methods for the first dynamic threshold, the second dynamic threshold, the third dynamic threshold, and the fourth dynamic threshold include: The first dynamic threshold is obtained based on the first preset default threshold, the minimum absolute value of the difference between adjacent elements of the mean array, the first correction factor, and the second correction factor. The second dynamic threshold is obtained based on the second preset default threshold, the minimum absolute value of the difference between adjacent elements of the maximum value array, the third correction factor, and the fourth correction factor; The third dynamic threshold is obtained based on the second preset default threshold, the minimum value of the absolute value of the difference between adjacent elements in the minimum value array, the third correction factor, and the fourth correction factor; The fourth dynamic threshold is obtained based on the second preset default threshold, the minimum value of the absolute value of the difference between the corresponding elements of the maximum and minimum value arrays, the third correction factor, and the fourth correction factor; The first correction factor is calculated using a first preset value, a target EGR rate, and a calibration value; the second correction factor is calculated using a second preset value, an EGR valve inlet temperature, an EGR valve inlet pressure, and a filtered value of the EGR valve inlet pressure; the third correction factor is calculated using a third preset value, a target EGR rate, and a calibration value; and the fourth correction factor is calculated using a fourth preset value, an EGR valve inlet temperature, an EGR valve inlet pressure, and a filtered value of the EGR valve inlet pressure. The calibration value is obtained by querying a preset second calibration table; the second calibration table stores the corresponding calibration values, indexed by the filtered value of the rotational speed and the target EGR valve opening.

10. The method according to claim 8, wherein, The calculation methods for the first fault count threshold and the second fault count include: Obtain the first ratio of the average absolute value of the fresh air intake flow rate entering the cylinder under the condition of signal stability to the preset flow rate; Obtain a second ratio between the average value of the mixing valve outlet pressure and the average value of the mixing valve inlet pressure under the condition of signal stability. The calculation steps for the first fault count threshold are as follows: by inputting the first ratio into the third or fourth calibration table, a first base value is obtained; by inputting the second ratio into the fifth or sixth calibration table, a second base value is obtained; the first base value and the second base value are multiplied and rounded to determine the first fault count threshold. Specifically, the third calibration table stores the corresponding first basic value using the first ratio as an index when the EGR valve is closed; the fifth calibration table stores the corresponding second basic value using the second ratio as an index when the EGR valve is closed; the fourth calibration table stores the corresponding first basic value using the first ratio as an index when the EGR valve is not closed; and the sixth calibration table stores the corresponding second basic value using the second ratio as an index when the EGR valve is not closed. The calculation steps for the second fault count threshold are as follows: by inputting the first ratio into the seventh or eighth calibration table, a third base value is obtained; by inputting the second ratio into the ninth or tenth calibration table, a fourth base value is obtained; the third base value and the fourth base value are multiplied together and rounded to determine the second fault count threshold. Specifically, the seventh calibration table stores the corresponding third basic value using the first ratio as an index when the EGR valve is closed; the ninth calibration table stores the corresponding fourth basic value using the second ratio as an index when the EGR valve is closed; the eighth calibration table stores the corresponding third basic value using the first ratio as an index when the EGR valve is not closed; and the tenth calibration table stores the corresponding fourth basic value using the second ratio as an index when the EGR valve is not closed.

11. An anomaly diagnosis system applied to an engine system, characterized in that, Capable of implementing the method of claim 1, comprising: The parameter filtering module is used to perform first-order low-pass filtering on each engine operating parameter using corresponding filtering coefficients to obtain the corresponding filtered value. The engine operating parameters include at least engine speed parameters and engine-related parameters. The filtering coefficient for each engine-related parameter is determined based on the stability of the engine speed parameters. The engine speed parameters include engine speed and rate of change of engine speed. The engine-related parameters include at least the EGR valve outlet pressure. The operating condition judgment module is used to, in response to determining that the engine operating condition is a steady-state condition using the engine operating parameters and the filtered value, preprocess the filtered value of the EGR valve outlet pressure within a first preset number of sampling periods to obtain an outlet pressure array; the outlet pressure array includes at least one of a maximum value array, a minimum value array, and a mean value array; The stability check module is used to determine whether the outlet pressure signal is faulty based on the stability of the speed change rate and the number of times the difference between adjacent elements of the outlet pressure array is greater than a dynamic value threshold; the dynamic value threshold is determined based on the engine operating parameters.

12. An electronic device, characterized in that, include: One or more processors; Memory, used to store one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement the method as described in claim 1.

13. A computer-readable medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method as described in claim 1.

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