Fault Diagnosis Method for Slow Response of Actuator

Abstract

The present invention relates to a fault diagnosis method for slow response of an actuator, comprising the steps of: parameter initialization; obtaining slow response fault monitoring enabling conditions; if all conditions are met, the fault monitoring is placed in an enabled state; the cumulative value of the slow response activation time is compared with a set time period threshold; the average value of the slow response error characteristic variable value is calculated; the average value of the slow response error characteristic variable value is compared with the average value threshold of the slow response error characteristic variable value; the cumulative value of the number of times of slow response exceeding the limit value is compared with the number threshold; if it is not less than, reporting that a slow response fault has been detected; otherwise, resetting the slow response activation time and the cumulative value of the slow response error characteristic variable value to 0. The present invention is clearly distinguished from other failure modes of the actuator, and further improves the accuracy of the slow response diagnosis of the actuator compared with the prior art; and eliminates the possibility of false alarms.

Description

Technical Field

[0001] The invention relates to the field of electronic control technology, and in particular to a fault diagnosis method for slow actuator response. Background Art

[0002] In order to meet the mandatory gas emission regulations and future requirements for reducing fuel consumption, it is particularly important to monitor diesel engines from all angles. Accurate monitoring of air system-related actuators is an important way to prevent excessive emissions and improve combustion performance. The Emission Limits and Measurement Methods for Pollutants from Heavy-Duty Diesel Vehicles (China Phase VI) GB 17691-2018 has clearly stipulated that the slow response of EGR actuators should be monitored.

[0003] After searching, the closest prior art to the present invention is the Chinese invention application with patent number CN202011375809.4, entitled “Detection method and system for response state of electronically controlled actuator of engine”, which discloses the following technical features:

[0004] 1. The detection method comprises the steps of: obtaining the processed demand execution opening according to the demand actuator opening through signal filtering processing; detecting the actual opening of the actuator; when the actual opening of the actuator is less than the demand actuator opening, monitoring the size of the actual opening of the actuator and the processed demand execution opening; when the actual opening of the actuator is always greater than or equal to the processed demand execution opening, determining that the actuator responds normally; when the actual opening of the actuator is less than the processed demand execution opening, the actuator is in a slow response state; accumulating the time when the actuator is in the slow response state, when the time when the actuator is in the slow response state is greater than or equal to the threshold time, determining that the actuator responds slowly.

[0005] 2. According to the demand actuator opening, after signal filtering processing, before obtaining the processed demand execution opening, it also includes: detecting the engine operating condition; when the engine operating condition meets the engine condition threshold, after detecting the demand actuator opening signal and delaying for a certain time, starting to accumulate the total execution time of the actuator.

[0006] 3. When the time when the actuator is in the slow response state is greater than or equal to the threshold time, the actuator responds slowly, specifically including: obtaining the slow response time ratio according to the time when the actuator is in the slow response state and the total execution time; when the slow response time ratio is greater than or equal to the threshold value, the actuator responds slowly.

[0007] 4. The detection system also includes: a signal filtering module: used to obtain the processed demand execution opening according to the demand actuator opening through signal filtering processing; an actuator opening detection module: used to detect the actual opening of the actuator; an actuator opening comparison module: used to monitor the size of the actual actuator opening and the processed demand execution opening when the actual actuator opening is smaller than the demand actuator opening; a first judgment module: used to judge that the actuator response is normal when the actual actuator opening is always greater than or equal to the processed demand execution opening; a second judgment module: used to judge that the actuator is in a slow response state when the actual actuator opening is smaller than the processed demand execution opening; the time when the actuator is in the slow response state is accumulated, and when the time when the actuator is in the slow response state is greater than or equal to the threshold time, the actuator is judged to be responding slowly.

[0008] The defects of the prior art are:

[0009] Since the accuracy of the slow response reported by the diagnostic strategy in the technical solution of the above-mentioned prior art is actually not high in terms of fault tolerance, it is very easy to generate false alarms when the actuator has a stuck fault, which is unacceptable. Summary of the invention

[0010] In view of the above problems, the present invention provides a fault diagnosis method for slow actuator response, which aims to clearly distinguish it from other failure modes of the actuator and further improve the accuracy of diagnosis of slow actuator response compared with the prior art, thereby eliminating the possibility of false alarms.

[0011] To solve the above problems, the technical solution provided by the present invention is:

[0012] A method for diagnosing a slow actuator response fault comprises the following steps:

[0013] S100. Start slow response fault monitoring; then perform parameter initialization operation;

[0014] S200. Obtaining the slow response fault monitoring enabling condition;

[0015] S300. Determine whether all the conditions for enabling the slow response fault monitoring are met, and then perform the following operations according to the determination result:

[0016] If the slow response fault monitoring enabling conditions are all met, execute S400;

[0017] If the slow response fault monitoring enabling conditions are not all met, execute S500;

[0018] S400. Enable fault monitoring; then execute S600;

[0019] S500. The fault monitoring is set to a disabled state; then returns and re-executes S200;

[0020] S600. Compare the accumulated value of the slow response activation time with the manually preset time period threshold; then perform the following operations based on the comparison result:

[0021] If the accumulated value of the slow response activation time is greater than the set time period threshold, execute S700;

[0022] If the accumulated value of the slow response activation time is not greater than the set time period threshold, it is determined again whether the slow response fault monitoring enabling conditions are all met, and then the following operations are performed according to the determination result:

[0023] If the slow response fault monitoring enabling conditions are all met, return to and re-execute S400;

[0024] If the slow response fault monitoring enabling conditions are not all met, return to and re-execute S500; S700. Calculate the average value of the slow response error characteristic variable value;

[0025] S800. Compare the average value of the slow response error characteristic variable value with the manually preset average value threshold of the slow response error characteristic variable value; then perform the following operations according to the comparison result:

[0026] If the average value of the slow response error characteristic variable value is not less than the average value threshold of the slow response error characteristic variable value, the cumulative value of the slow response exceeding limit value times is incremented by 1; then S900 is executed;

[0027] If the average value of the slow response error characteristic variable value is less than the average value threshold of the slow response error characteristic variable value, the accumulated value of the slow response exceeding limit value times is reset to 0; then S900 is executed;

[0028] S900. Compare the cumulative value of the number of times the slow response exceeds the limit value with the manually preset number threshold; then perform the following operations based on the comparison result:

[0029] If the cumulative value of the number of times the slow response exceeds the limit value is not less than the number threshold, execute S1000;

[0030] If the cumulative value of the number of times the slow response exceeds the limit value is less than the number threshold, executing S1100;

[0031] S1000. Report that a slow response fault has been detected; then end the fault diagnosis process;

[0032] S1100. Reset the accumulated value of the slow response activation time to 0; and at the same time reset the accumulated value of the slow response error characteristic variable value to 0; and then return to and execute S200 again.

[0033] Preferably, the parameter initialization operation in S100 specifically includes the following steps:

[0034] S110. Initialize the accumulated value of the slow response activation time to 0;

[0035] S120. Initialize the accumulated value of the slow response error characteristic variable value to 0;

[0036] S130. Initialize the accumulated value of the number of times the slow response exceeds the limit value to 0.

[0037] Preferably, the slow response fault monitoring enabling condition in S300 specifically includes the following contents:

[0038] The engine operating condition meets the preset conditions, including: the engine speed is within the manually preset normal speed range, and the engine load is within the manually preset normal load range;

[0039] There are no other faults in the actuator, including no electrical faults;

[0040] The actuator's required opening position change rate exceeds the manually preset opening position change rate threshold;

[0041] The deviation between the actuator's required opening and the actuator's actual opening exceeds the manually preset opening deviation threshold.

[0042] Preferably, after the fault monitoring is set to an enabled state in S400, the following steps are further included:

[0043] S410. The slow response activation time starts to accumulate, and is expressed as follows:

[0044] Ta=Ta+T

[0045] Wherein: T is the slow response activation time, in seconds; Ta is the cumulative value of the slow response activation time, in seconds;

[0046] S420. Start accumulating the slow response error characteristic variable value, expressed as follows:

[0047] Sa=Sa+S

[0048] Wherein: S is the slow response error characteristic variable value, in %, and Sa is the cumulative value of the slow response error characteristic variable value, in %.

[0049] Preferably, the slow response error characteristic variable value is expressed as follows:

[0050]

[0051] Where: P dem is the required opening of the actuator, in %; P act is the actual opening of the actuator, in %; D p is the change rate of the actuator's required opening position, in %.

[0052] Preferably, after the fault monitoring is set to a disabled state in S500 and before returning to and re-executing S200, the following steps are further included:

[0053] S510. Pause the corresponding accumulation process of the slow response activation time, and store the current accumulated value of the slow response activation time;

[0054] S520. Pause the corresponding accumulation process of the slow response error characteristic variable value, and store the current accumulated value of the slow response error characteristic variable value.

[0055] Preferably, the average value of the slow response error characteristic variable value calculated in S700 is expressed as follows:

[0056]

[0057] Where: S avg is the average value of the slow response error characteristic variable.

[0058] Preferably, in S300, the transient state of the actuator is determined by the relationship between the required opening position change rate of the actuator and the set opening position change rate threshold. Specifically:

[0059] If the required opening position change rate of the actuator is greater than the set opening position change rate threshold in the opening direction, it is determined that the actuator is in a transient state in the opening direction;

[0060] If the required opening position change rate of the actuator is less than the set opening position change rate threshold in the closing direction, it is determined that the actuator is in a transient state in the closing direction.

[0061] Preferably, in S300, the direction of the actuator is determined by the relationship between the deviation between the required opening of the actuator and the actual opening of the actuator and the set opening deviation threshold. Specifically:

[0062] If the deviation between the required opening of the actuator and the actual opening of the actuator is greater than the set opening deviation threshold of the opening direction, it is determined that the actuator is in the opening direction;

[0063] If the deviation between the actuator required opening and the actuator actual opening is smaller than the set opening deviation threshold of the closing direction, it is determined that the actuator is in the closing direction.

[0064] Preferably, in S1000, it is reported that a slow response fault has been detected, and the transient state of the actuator and the direction of the actuator are also returned.

[0065] Compared with the prior art, the present invention has the following advantages:

[0066] 1. Due to the definition of the transient diagnostic window for slow actuator response and the application of the error characteristic variable value when the transient diagnostic window is opened, the present invention can clearly distinguish the actuator from other failure modes, and further improve the accuracy of the actuator slow response diagnosis compared with the prior art;

[0067] 2. Since the present invention determines whether the diagnostic window is activated based on the rate of change of the actuator's required opening, and also calculates the slow response error characteristic variable value based on the actuator's required opening, the actuator's actual opening, and the rate of change of the actuator's required opening, and when the diagnostic window is activated, the activation time is accumulated, and the slow response error characteristic variable value is accumulated. Only when the accumulated activation time reaches the preset time threshold, it is determined whether the accumulated response slow error characteristic variable value exceeds the preset error threshold. If it exceeds, it is determined to be an actuator slow response fault, thereby eliminating the possibility of false alarms. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Figure 1 It is a schematic diagram of the actuator slow response fault monitoring process according to a specific embodiment of the present invention;

[0069] Figure 2 It is a schematic diagram of calculating the valve slow response error characteristic variable value according to a specific embodiment of the present invention. DETAILED DESCRIPTION

[0070] The present invention is further explained below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, various equivalent forms of modifications to the present invention by those skilled in the art all fall within the scope defined by the claims attached to this application.

[0071] like Figure 1 As shown, a fault diagnosis method for slow actuator response includes the following steps:

[0072] S100. Start slow response fault monitoring; then perform parameter initialization operation.

[0073] In this specific embodiment, the parameter initialization operation in S100 specifically includes the following steps:

[0074] S110. Initialize the accumulated value of the slow response activation time to 0.

[0075] S120. Initialize the accumulated value of the slow response error characteristic variable value to 0.

[0076] S130. Initialize the accumulated value of the number of times the slow response exceeds the limit value to 0.

[0077] It should be noted that the function of S100 is to respond to the start of slow fault monitoring and initialize the parameters that need to be calculated.

[0078] S200. Obtain the slow response fault monitoring enabling condition.

[0079] S300. Determine whether all the conditions for enabling the slow response fault monitoring are met, and then perform the following operations according to the determination result:

[0080] If all the slow response fault monitoring enabling conditions are met, S400 is executed.

[0081] If the slow response fault monitoring enabling conditions are not all met, S500 is executed.

[0082] It should be noted that after obtaining the slow response fault monitoring enabling conditions, the fault monitoring enabling judgment is performed; only when all the above slow response fault monitoring enabling conditions are met, the fault monitoring is set to the enabled state.

[0083] In this specific embodiment, the slow response fault monitoring enabling condition in S300 specifically includes the following:

[0084] The engine operating condition meets the preset conditions, including: the engine speed is within a manually preset normal speed range, and the engine load is within a manually preset normal load range.

[0085] There are no other faults with the actuator, including no electrical faults.

[0086] The actuator's required opening position change rate exceeds the manually preset opening position change rate threshold.

[0087] The deviation between the actuator's required opening and the actuator's actual opening exceeds the manually preset opening deviation threshold.

[0088] In this specific embodiment, in S300, the transient state of the actuator is determined by the relationship between the actuator required opening position change rate and the set opening position change rate threshold. Specifically:

[0089] If the actuator required opening position change rate is greater than the set opening position change rate threshold in the opening direction, it is determined that the actuator is in a transient state in the opening direction.

[0090] If the actuator required opening position change rate is less than the set opening position change rate threshold in the closing direction, it is determined that the actuator is in a transient state in the closing direction.

[0091] It should be noted that the actuator required opening position change rate refers to the current actuator required opening minus the previous actuator required opening, divided by the required time.

[0092] In this specific embodiment, S300 also determines the direction of the actuator by the relationship between the deviation between the actuator required opening and the actual actuator opening and the set opening deviation threshold. Specifically,

[0093] If the deviation between the actuator required opening and the actuator actual opening is greater than the set opening deviation threshold of the opening direction, it is determined that the actuator is in the opening direction.

[0094] If the deviation between the actuator required opening and the actuator actual opening is less than the set opening deviation threshold in the closing direction, it is determined that the actuator is in the closing direction.

[0095] S400. Enable fault monitoring; then execute S600.

[0096] In this specific embodiment, after the fault monitoring is set to an enabled state in S400, the following steps are also included:

[0097] S410. Start accumulating the slow response activation time, expressed as follows:

[0098] Ta=Ta+T(1)

[0099] Where: T is the slow response activation time, in seconds; Ta is the cumulative value of the slow response activation time T, in seconds.

[0100] S420. Start accumulating the slow response error characteristic variable value, expressed as follows:

[0101] Sa=Sa+S(2)

[0102] Wherein: S is the slow response error characteristic variable value, unit is %; Sa is the cumulative value of the slow response error characteristic variable value S, unit is %.

[0103] In this specific embodiment, the slow response error characteristic variable value is expressed as follows:

[0104]

[0105] Where: P dem is the required opening of the actuator, in %; P act is the actual opening of the actuator, in %; D pThe required opening position change rate of the actuator, in %.

[0106] It should be noted that if Figure 2 As shown, the calculation principle of the slow response error characteristic variable value is as follows:

[0107] Figure 2 In the figure, the horizontal axis represents time, the vertical axis represents the valve opening, the blue curve represents the required valve opening, and the pink curve represents the actual valve opening.

[0108] At time T', the required valve opening is at point A, and the slope of the required valve opening is ff', assumed to be df; the actual valve opening is point B'.

[0109] The valve opening process is divided into many small time periods. From point C to point A, it represents a unit time dt, that is, CB. Then the cumulative area of ​​the valve opening requirement within the time dt can be represented as the area S of the triangle ΔABC. dem , expressed by formula (4):

[0110]

[0111] because So the area of ​​ΔABC is S dem It can be further expressed as formula (5):

[0112]

[0113] At time T', the deviation between the required valve opening and the actual valve opening is AB'; obviously, the larger the deviation, the smaller the area S of the triangle ΔAB'C'. act The larger the value, the greater the value. This is because according to formula (6):

[0114]

[0115] Therefore, the area of ​​triangle ΔAB'C' is S act It can be further expressed as formula (7):

[0116]

[0117] It should be further explained that, in the above description, the physical meaning of dt is a unit time representing the change of valve opening; and the physical meaning of df is the change slope of the valve demand opening.

[0118] S500. Set fault monitoring to a disabled state; then return and re-execute S200.

[0119] In this specific embodiment, after the fault monitoring is set to a disabled state in S500 and after returning to and re-executing S200, the following steps are further included:

[0120] S510. Pause the corresponding accumulation process of the slow response activation time, and store the current accumulated value of the slow response activation time.

[0121] S520. Pause the accumulation process of the corresponding slow response error characteristic variable value, and store the current accumulated value of the slow response error characteristic variable value.

[0122] It should be noted that the meaning of S510~S520 is: if the slow response fault monitoring enabling condition set at S200 is not met, the accumulation process of the slow response activation time T is suspended, and the current accumulated value Ta of the slow response activation time is stored; at the same time, the accumulation process of the corresponding slow response error characteristic variable value S is suspended, and the current accumulated value Sa of the slow response error characteristic variable value is stored; then return to S200 to judge the slow response fault monitoring enabling condition; if the slow response fault monitoring enabling condition is met, then based on the accumulated value of the slow response activation time and the accumulated value of the slow response error characteristic variable value stored last time, continue to accumulate the accumulated value of the slow response activation time and the accumulated value of the slow response error characteristic variable value.

[0123] S600. Compare the accumulated value of the slow response activation time with the manually preset time period threshold; then perform the following operations based on the comparison result:

[0124] If the accumulated value of the slow response activation time is greater than the set time period threshold, S700 is executed.

[0125] If the accumulated value of the slow response activation time is not greater than the set time period threshold, it is determined again whether all the conditions for enabling the slow response fault monitoring are met, and then the following operations are performed according to the determination result:

[0126] If all the conditions for enabling the slow response fault monitoring are met, the process returns to and re-executes S400 .

[0127] If the slow response fault monitoring enabling conditions are not all met, the process returns to and re-executes S500 .

[0128] S700. Calculate the average value of the slow response error characteristic variable value.

[0129] In this specific embodiment, the average value of the slow response error characteristic variable value calculated in S700 is expressed as follows:

[0130]

[0131] Where: S avg is the average value of the slow response error characteristic variable.

[0132] S800. Compare the average value of the slow response error characteristic variable value with the manually preset average value threshold of the slow response error characteristic variable value; then perform the following operations according to the comparison result:

[0133] If the average value of the slow response error characteristic variable value is not less than the average value threshold of the slow response error characteristic variable value, the accumulated value of the number of slow response exceeding limit value is increased by 1; and then S900 is executed.

[0134] If the average value of the slow response error characteristic variable value is less than the average value threshold of the slow response error characteristic variable value, the accumulated value of the slow response limit value times is reset to 0; and then S900 is executed.

[0135] S900. Compare the cumulative value of the number of times the slow response exceeds the limit with the manually preset number threshold N max Compare; then perform the following operations based on the comparison results:

[0136] If the cumulative value of the number of times the slow response exceeds the limit value is not less than the number threshold, S1000 is executed.

[0137] If the cumulative value of the number of times the slow response exceeds the limit value is less than the number threshold, S1100 is executed.

[0138] It should be noted that S600 to S900 are the process of determining whether a slow response fault occurs. The physical meaning is:

[0139] When the accumulated value of slow response activation time Ta is greater than the set time period threshold t 1 t1, then calculate the average value S of the slow response error characteristic variable value avg ; if S avg The average value threshold S greater than or equal to the slow response error characteristic variable value min , then the cumulative value of the number of times the slow response exceeds the limit value is added by 1, expressed as follows:

[0140] N=N+1 (9)

[0141] If S avg The average value threshold S of the characteristic variable value of the slow response error is less than min , then the cumulative value N of the number of times the slow response exceeds the limit value is reset to 0, expressed as follows:

[0142] N=0 (10)

[0143] S1000. Report that a slow response fault has been detected; then end the fault diagnosis process.

[0144] In this specific embodiment, S1000 reports that a slow response fault has been detected, and also returns whether the actuator responds slowly in the opening direction or the closing direction.

[0145] S1100. Reset the accumulated value of the slow response activation time to 0; and at the same time reset the accumulated value of the slow response error characteristic variable value to 0; and then return to and execute S200 again.

[0146] It should be noted that the role of S1100 is to provide a backup for the process. That is, if the reporting conditions of S1000 are not met at this time, the fault diagnosis process will continue, namely:

[0147] If the cumulative number of times the slow response exceeds the limit value N is less than the number threshold N max , the accumulated value Ta of the slow response activation time is reset, and at the same time the accumulated value Sa of the slow response error characteristic variable value is reset, and then the process returns to S200 for a new round of monitoring calculation.

[0148] If the cumulative number of times the response is slow exceeding the limit value N is greater than the number threshold N max , that is, continuous N max The first time S avg The average value threshold S greater than or equal to the slow response error characteristic variable value min , a slow response fault is reported.

[0149] It should be further explained that here, the result in S300 can also be combined to judge and output whether the actuator is slow to respond in the opening direction or slow to respond in the closing direction.

[0150] In the above detailed description, various features are grouped together in a single embodiment to simplify the disclosure. This method of disclosure should not be interpreted as reflecting an intention that the embodiments of the claimed subject matter require more features than are clearly stated in each claim. On the contrary, as reflected in the appended claims, the invention is in a state of having less than all the features of the disclosed individual embodiments. Therefore, the appended claims are hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate preferred embodiment of the invention.

[0151] The disclosed embodiments are described above to enable any person skilled in the art to implement or use the present invention. Various modifications of these embodiments are obvious to those skilled in the art, and the general principles defined herein may also be applied to other embodiments without departing from the spirit and scope of the present disclosure. Therefore, the present disclosure is not limited to the embodiments given herein, but is consistent with the broadest scope of the principles and novel features disclosed in this application.

[0152] The above description includes examples of one or more embodiments. Of course, it is not possible to describe all possible combinations of components or methods for the purpose of describing the above embodiments, but it should be recognized by those skilled in the art that the various embodiments may be further combined and arranged. Therefore, the embodiments described herein are intended to cover all such changes, modifications and variations that fall within the scope of protection of the appended claims. In addition, with respect to the term "comprising" used in the specification or claims, the word is covered in a manner similar to the term "including", just as "including," is explained as a transitional word in the claims. In addition, any term "or" used in the specification of the claims is intended to mean "non-exclusive or".

[0153] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A fault diagnosis method for slow actuator response, characterized in that: The following steps are involved: S100. Start slow response fault monitoring; then perform parameter initialization operation; S200. Obtaining the slow response fault monitoring enabling condition; S300. Determine whether all the conditions for enabling the slow response fault monitoring are met, and then perform the following operations according to the determination result: If the slow response fault monitoring enabling conditions are all met, execute S400; If the slow response fault monitoring enabling conditions are not all met, execute S500; S400. Enable fault monitoring; then execute S600; S500. The fault monitoring is set to a disabled state; then returns and re-executes S200; S600. Compare the accumulated value of the slow response activation time with the manually preset time period threshold; then perform the following operations based on the comparison result: If the accumulated value of the slow response activation time is greater than the set time period threshold, execute S700; If the accumulated value of the slow response activation time is not greater than the set time period threshold, it is determined again whether all the slow response fault monitoring enabling conditions are met, and then the following operations are performed according to the determination result: If the slow response fault monitoring enabling conditions are all met, return to and re-execute S400; If the slow response fault monitoring enabling conditions are not all met, return to and re-execute S500; S700. Calculate the average value of the slow response error characteristic variable value; S800. Compare the average value of the slow response error characteristic variable value with the manually preset average value threshold of the slow response error characteristic variable value; then perform the following operations according to the comparison result: If the average value of the slow response error characteristic variable value is not less than the average value threshold of the slow response error characteristic variable value, the cumulative value of the slow response exceeding limit value times is incremented by 1; then S900 is executed; If the average value of the slow response error characteristic variable value is less than the average value threshold of the slow response error characteristic variable value, the accumulated value of the slow response exceeding limit value times is reset to 0; then S900 is executed; S900. Compare the cumulative value of the number of times the slow response exceeds the limit value with the manually preset number threshold; then perform the following operations based on the comparison result: If the cumulative value of the number of times the slow response exceeds the limit value is not less than the number threshold, execute S1000; If the cumulative value of the number of times the slow response exceeds the limit value is less than the number threshold, executing S1100; S1000. Report that a slow response fault has been detected; then end the fault diagnosis process; S1100. Reset the cumulative value of the slow response activation time to 0; reset the cumulative value of the slow response error characteristic variable value to 0; then return to and execute S200 again; The parameter initialization operation in S100 specifically includes the following steps: S110. Initialize the accumulated value of the slow response activation time to 0; S120. Initialize the accumulated value of the slow response error characteristic variable value to 0; S130. Initialize the accumulated value of the number of times the slow response exceeds the limit value to 0; The slow response fault monitoring enabling conditions described in S300 specifically include the following: The engine operating condition meets the preset conditions, including: the engine speed is within the manually preset normal speed range, and the engine load is within the manually preset normal load range; There are no other faults in the actuator, including no electrical faults; The actuator's required opening position change rate exceeds the manually preset opening position change rate threshold; The deviation between the actuator's required opening and the actuator's actual opening exceeds the manually preset opening deviation threshold; After enabling fault monitoring in S400, the following steps are also included: S410. The slow response activation time starts to accumulate, and is expressed as follows: Ta=Ta+T Wherein: T is the slow response activation time, in seconds; Ta is the cumulative value of the slow response activation time, in seconds; S420. Start accumulating the slow response error characteristic variable value, expressed as follows: Sa=Sa+S Wherein: S is the slow response error characteristic variable value, in %; Sa is the cumulative value of the slow response error characteristic variable value, in %; The slow response error characteristic variable value is expressed as follows: Where: P dem is the required opening of the actuator, in %; P act is the actual opening of the actuator, in %; D p is the required opening position change rate of the actuator, in %; After the fault monitoring is set to a disabled state in S500 and then returns to and re-executes S200, the following steps are also included: S510. Pause the corresponding accumulation process of the slow response activation time, and store the current accumulated value of the slow response activation time; S520. Pause the corresponding accumulation process of the slow response error characteristic variable value, and store the current accumulated value of the slow response error characteristic variable value; The average value of the slow response error characteristic variable value calculated in S700 is expressed as follows: Where: S avg is the average value of the slow response error characteristic variable value; In S300, the transient state of the actuator is determined by the relationship between the actuator required opening position change rate and the set opening position change rate threshold. Specifically: If the required opening position change rate of the actuator is greater than the set opening position change rate threshold in the opening direction, it is determined that the actuator is in a transient state in the opening direction; If the required opening position change rate of the actuator is less than the set opening position change rate threshold in the closing direction, it is determined that the actuator is in a transient state in the closing direction; In S300, the direction of the actuator is determined by the relationship between the deviation between the required opening of the actuator and the actual opening of the actuator and the set opening deviation threshold. Specifically: If the deviation between the required opening of the actuator and the actual opening of the actuator is greater than the set opening deviation threshold of the opening direction, it is determined that the actuator is in the opening direction; If the deviation between the required opening of the actuator and the actual opening of the actuator is less than the set opening deviation threshold of the closing direction, it is determined that the actuator is in the closing direction; S1000 reports that a slow response fault has been detected, and also returns the transient state of the actuator and the direction of the actuator.

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