An engine fault diagnosis method, device, medium and vehicle

Abstract

The present application belongs to the technical field of automobile control, and particularly relates to an engine fault diagnosis method, device, medium and vehicle. For the vehicle type with single operation condition of engine VVT system such as extended-range electric vehicle or plug-in hybrid vehicle, the engine fault diagnosis can be completed by comparing the VVT actual opening degree and the VVT target opening degree by mathematical means, which overcomes the technical prejudice that the VVT actual opening degree needs to jump in the large, medium and small three intervals respectively before the fault diagnosis of the existing fuel vehicle, and has the significant advantages of simplicity, high efficiency and accuracy. The present application judges whether the engine VVT has a rationality fault when the VVT target opening degree value changes, and also solves the technical problem that the VVT target opening degree and the VVT actual opening degree deviation continuously exceed the threshold value in the prior art, which can trigger the VVT rationality fault judgment, thereby leading to poor diagnosis sensitivity.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of automobile control, and particularly relates to an engine fault diagnosis method, device, medium and vehicle. BACKGROUND

[0002] In recent years, range extend electric vehicles (REEV) have been valued by many domestic automobile manufacturers. Due to the advantages of being able to use oil and electricity and having no range anxiety, REEVs have also been favored by more and more consumers. For example, the REEV models such as Ideal ONE, HiPhi M5 and Changan Deep Blue SL03 have good market performance.

[0003] In order to better save energy and reduce emissions, the engines of REEVs are basically equipped with VVT (Variable Valve Timing) variable valve timing technology. Usually in the engine bench calibration stage, engineers will comprehensively select the best VVT target opening according to the pollutant emission results, fuel consumption and other indicators. In the actual driving process of the vehicle, whether the VVT actual opening can closely follow the VVT target opening seriously affects the performance of the vehicle such as emission and fuel consumption. Therefore, the CN6 regulation puts forward clear requirements for the detection of the VVT system of the gasoline engine, and requires that the OBD system of the vehicle can timely diagnose two rationality faults of VVT target error and response delay. The VVT target error fault detection is whether the VVT can achieve the required valve timing of the system. If the VVT actual opening cannot always reach the target opening, the fault is reported. The VVT response delay fault detection is whether the VVT can achieve the required valve timing of the system within a specified time. If the VVT is slow and cannot reach the target opening within the specified time, the fault is reported. In addition, in order to ensure that the rationality diagnosis of VVT target error and response delay can be timely and effectively performed, the CN6 regulation also clearly stipulates that the VVT related rationality diagnosis must be completed in the WLTC emission cycle, and the REEV model must also meet this requirement.

[0004] The current commonly used VVT rationality fault diagnosis strategy is: when the VVT system actually exists rationality fault, if the deviation of VVT target opening degree and actual opening degree continuously exceeds the threshold value, the system monitors the measured value of VVT within the calibration period T1, if the maximum value of the measured value of VVT does not reach the calibration threshold value, the pre-fault flag opening degree is obtained, and then the pre-fault is target error or response delay fault by analyzing the size of the actual opening degree of VVT within the calibration period T2; when the VVT system is fault-free, the system detects the actual opening degree of VVT, if the actual opening degree of VVT can run to the large, medium and small three intervals, and the residence time in each interval is greater than the sum of the above calibration periods T1 and T2, the counter is added by 1, when the counter exceeds the calibration threshold value, the VVT rationality fault-free diagnosis is completed, that is, it is needed to judge whether the actual opening degree of VVT can reach the target opening degree in the three intervals.

[0005] The current commonly used VVT rationality fault diagnosis strategy is directly applied to the extended range or plug-in hybrid vehicle with single operation condition, and the deficiency is that the VVT system of the extended range or plug-in hybrid vehicle has single operation condition, and the engine speed fluctuation condition is less, such as shown in Figure 4 and Figure 5 It can be seen that the VVT opening degree limit of the REEV vehicle is either stationary at the lock position or fluctuates slightly in the large opening degree area, and the corresponding VVT target / actual opening degree also does not frequently jump in the large, medium and small three intervals, so that the VVT rationality fault cannot be diagnosed in time. SUMMARY

[0006] The engine fault diagnosis method for engine VVT fault diagnosis of extended range electric vehicle or plug-in hybrid vehicle, comprising a first information acquisition step and a second fault judgment step, wherein,

[0007] The first information acquisition step acquires, scans or exchanges the VVT actual opening degree and the VVT target opening degree;

[0008] The first information acquisition step acquires, scans or exchanges the VVT actual opening degree and the VVT target opening degree;

[0009] The second fault judgment step, when the engine VVT exists rationality fault, compares the VVT actual opening degree and the VVT target opening degree by mathematical means, and judges whether the engine VVT state is response delay fault or target error fault.

[0010] The embodiment has the advantages that for a vehicle model with a single VVT system operating condition, engine fault diagnosis can be completed by comparing the VVT actual opening degree and the VVT target opening degree by using mathematical means, the technical prejudice that the VVT actual opening degree needs to jump in the large, medium and small three intervals to complete fault diagnosis is overcome, and the method has the advantages of simplicity, high efficiency and accuracy.

[0011] Further, the method further comprises a third comprehensive decision step of diagnosing the final state of the engine VVT in combination with more than three times of judgments completed by the second fault judgment step within a preset time.

[0012] The embodiment has the advantages that although the VVT actual opening degree and the VVT target opening degree comparison limit is either stationary at the lock position or moves to the large opening degree region with small amplitude fluctuation when the engine operating condition is single, there is a certain probability of special cases, and simple mathematical comparison may cause misdiagnosis when the VVT actual opening degree and the VVT target opening degree are in the large and medium intervals; therefore, the comprehensive decision can effectively solve the technical problem of misdiagnosis in special cases, and the technical problem is found by using mathematical comparison judgment and a large number of experiments and observations.

[0013] Further, the method further comprises a diagnosis triggering step of judging whether the engine VVT has a rationality fault according to the VVT actual opening degree and the VVT target opening degree obtained, scanned or exchanged by the first information acquisition step when the VVT target opening degree value changes.

[0014] Specifically, the specific method for judging whether the engine VVT has a rationality fault is as follows:

[0015] When the absolute value of the difference between the VVT target opening degree value and the VVT lock position is greater than the first threshold value, the absolute value of the deviation value of the VVT actual opening degree and the VVT target opening degree in the time period is integrated, and the average deviation value of the integral in a unit time period is calculated; if the average deviation value of the unit time period is greater than the second threshold value, it is judged that the engine VVT state has a rationality fault; otherwise, it is judged that the engine VVT state does not have a rationality fault.

[0016] The embodiment has the advantages that when the VVT system actually has a rationality fault, the traditional judgment mode is that the VVT target opening 120 and the VVT actual opening 120 deviation continuously exceeds the threshold value, and the VVT rationality fault judgment is triggered, if the VVT target opening 120 and the VVT actual opening 120 deviation is temporarily less than the calibration threshold value in the middle, the current diagnosis is exited, and the current diagnosis triggering strategy is not conducive to timely and rapid fault reporting. The present application immediately diagnoses the VVT system when the VVT target opening changes, and the sensitivity of triggering diagnosis can be adjusted by adjusting the length of the unit time, the size of the first threshold value and the second threshold value. It solves the technical problems of poor diagnosis sensitivity caused by the fact that the VVT target opening and the VVT actual opening deviation continuously exceeds the threshold value, and the VVT rationality fault judgment is triggered.

[0017] Specifically, in the second fault judgment step, whether the engine VVT state is a response delay fault or a target error fault is judged, and the specific method is:

[0018] If the average deviation value is greater than the second threshold value and less than the third threshold value, it is judged that the engine VVT state is a response delay fault;

[0019] If the average deviation value is greater than the third threshold value, it is judged that the engine VVT state is a target error fault.

[0020] Specifically, in the third comprehensive decision step, the final state of the engine VVT is diagnosed, and the specific method is:

[0021] If the number of times that the engine VVT state is judged to be a response delay fault or a target error fault in the second fault judgment step within the preset time exceeds the diagnosis preset value, it is diagnosed that the final state of the engine VVT is a response delay fault or a target error fault;

[0022] If the engine is turned off during the process of the second fault judgment step or the third comprehensive decision step, the current fault diagnosis is interrupted.

[0023] Specifically, the specific method for judging whether the engine VVT has a rationality fault is:

[0024] The deviation of the VVT actual opening and the VVT target opening is calculated, and if the integral of the deviation is greater than the second threshold value within the preset time period, it is judged that the engine VVT state has a rationality fault; otherwise, it is judged that the engine VVT state does not have a rationality fault.

[0025] Specifically, in the second fault judgment step, whether the engine VVT state is a response delay fault or a target error fault is judged, and the specific method is:

[0026] If the number of times that the VVT actual opening degree is derived is less than the third threshold value, it is determined that the engine VVT state is a response delay fault; otherwise, it is determined that the engine VVT state is a target error fault.

[0027] The application further discloses an engine fault diagnosis device for engine VVT fault diagnosis of a range-extended electric vehicle or a plug-in hybrid vehicle, comprising a first information acquisition unit and a second fault judgment unit.

[0028] The first information acquisition unit acquires, scans or exchanges the VVT actual opening degree and the VVT target opening degree.

[0029] The second fault judgment unit compares the VVT actual opening degree and the VVT target opening degree by mathematical means when the engine VVT has a rationality fault, and determines whether the engine VVT state is a response delay fault or a target error fault.

[0030] Further, the third comprehensive decision unit is further included, which diagnoses the final state of the engine VVT in combination with more than three times of judgments completed by the second fault judgment unit within a preset time.

[0031] Further, the diagnosis triggering unit is further included, which determines whether the engine VVT has a rationality fault according to the VVT actual opening degree and the VVT target opening degree acquired, scanned or exchanged by the first information acquisition unit when the VVT target opening degree value changes.

[0032] Specifically, the diagnosis triggering unit integrates the absolute value of the deviation value of the VVT actual opening degree and the VVT target opening degree within the time period when the absolute value of the difference between the VVT target opening degree value and the VVT locking position is greater than the first threshold value, and then calculates the average deviation value of the integral in a unit time period; if the average deviation value of the unit time period is greater than the second threshold value, it is determined that the engine VVT state has a rationality fault, and the engine VVT state is determined by the second fault judgment unit; otherwise, it is determined that the engine VVT state does not have a rationality fault.

[0033] Specifically, the second fault judgment unit determines that the engine VVT state is a response delay fault when the average deviation value is greater than the second threshold value and less than the third threshold value, and determines that the engine VVT state is a target error fault when the average deviation value is greater than the third threshold value.

[0034] Specifically, within the preset time, if the number of times that the second fault judgment unit determines that the engine VVT state is a response delay fault or a target error fault exceeds a diagnosis preset value, the third comprehensive decision unit diagnoses that the final state of the engine VVT is a response delay fault or a target error fault.

[0035] Specifically, the second fault judging unit calculates the deviation of the VVT actual opening degree and the VVT target opening degree, and if the integral of the deviation is greater than a second threshold value within a preset time period, it is determined that the engine VVT state has a rationality fault; otherwise, it is determined that the engine VVT state does not have a rationality fault.

[0036] Specifically, the VVT actual opening degree is derived several times within a preset time period from the starting point of the change of the VVT target opening degree, and if the number of times of derivation of the VVT actual opening degree is less than a third threshold value, the second fault judging unit determines that the engine VVT state is a response delay fault; otherwise, the second fault judging unit determines that the engine VVT state is a target error fault.

[0037] Similarly, the application also discloses a computer storage medium storing a plurality of computer programs, and a processor can execute the computer programs to implement any of the above engine fault diagnosis methods.

[0038] Similarly, the application also discloses a vehicle comprising any of the above engine fault diagnosis devices; and / or any of the above computer storage media; the vehicle also comprises a range-extending vehicle VVT engine or a plug-in hybrid vehicle VVT engine.

[0039] It should be noted that the terms "first", "second", and the like similar terms used in the present application are only used to describe the elements in the technical solutions, and do not constitute a limitation on the technical solutions, nor can they be understood as an indication or suggestion of the importance of the corresponding elements; the elements with "first", "second", and the like similar terms represent at least one in the corresponding technical solution. BRIEF DESCRIPTION OF DRAWINGS

[0040] In order to more clearly illustrate the technical solutions of the application, facilitate further understanding of the technical effects, technical features and purposes of the application, the application will be described in detail below in conjunction with the drawings, which constitute an essential part of the specification and together with the embodiments of the application serve to illustrate the technical solutions of the application, but do not constitute a limitation on the application.

[0041] The same reference numerals in the drawings represent the same components, specifically:

[0042] Figure 1 The flowchart of Example 1.

[0043] Figure 2 The flowchart of the engine fault diagnosis method.

[0044] Figure 3 The structural diagram of the engine fault diagnosis device.

[0045] Figure 4 The VVT working condition operation comparison chart for REEV vehicle and pure internal combustion engine vehicle.

[0046] Figure 5 The VVT system of REEV vehicle in three states, VVT target opening and VVT actual opening comparison chart.

[0047] Wherein:

[0048] 100, the first information acquisition step

[0049] 110, VVT actual opening;

[0050] 120, VVT target opening;

[0051] 150, diagnosis triggering step;

[0052] 160, the first threshold value;

[0053] 170, the second threshold value;

[0054] 180, the third threshold value;

[0055] 200, the second fault judgment step;

[0056] 210, engine VVT state;

[0057] 300, the third comprehensive decision step;

[0058] 310, engine VVT final state;

[0059] 320, diagnosis preset value;

[0060] 600, engine fault diagnosis device;

[0061] 610, the first information acquisition unit;

[0062] 615, diagnosis triggering unit;

[0063] 620, the second fault judgment unit;

[0064] 630, the third comprehensive decision unit. DETAILED DESCRIPTION

[0065] The present application will be further described below in conjunction with the drawings and examples. Of course, the following description of specific examples is only to explain the technical solutions of the present application, and is not a limitation of the present application. In addition, the parts expressed in the examples or the drawings are only examples of the relevant parts of the present application, and not the whole of the present application.

[0066] Example 1:

[0067] AsFigure 1 As shown in the figure, an engine fault diagnosis method is used for engine VVT fault diagnosis of extended-range electric vehicles or plug-in hybrid vehicles, and the specific steps are as follows:

[0068] S1, a first information acquisition step 100;

[0069] The VVT actual opening degree 110 and the VVT target opening degree 120 are acquired, scanned or exchanged; in this step, the acquisition method can be through data interaction with the ECU, or the VVT target opening degree 120 can be obtained by calculation, the VVT actual opening degree 110 can be obtained by sensor measurement, or any other method that can obtain the actual opening degree 110 and the VVT target opening degree 120.

[0070] S2, a diagnosis triggering step 150;

[0071] According to the VVT actual opening degree 110 and the VVT target opening degree 120 acquired, scanned or exchanged in the first information acquisition step 100, when the VVT actual opening degree 110 value changes, it is judged whether the engine VVT has a rationality fault.

[0072] Specifically, when the absolute value of the difference between the VVT target opening degree 120 value and the VVT lock position is greater than the first threshold value 160, the absolute value of the deviation between the VVT actual opening degree 110 and the VVT target opening degree 120 in this time period is integrated, and the average deviation value of the integral in the unit time period is calculated; if the average deviation value of the unit time period is greater than the second threshold value 170, it is judged that the engine VVT state 210 has a rationality fault, and the second fault judgment step 200 is started; otherwise, it is judged that the engine VVT state 210 does not have a rationality fault, and the second fault judgment step 200 is not started.

[0073] In this step, when the VVT target opening degree changes, the deviation value calculation and the judgment of whether there is a rationality fault are started, and other methods can also be used to judge whether there is a rationality fault.

[0074] S3, a second fault judgment step 200;

[0075] When the engine VVT has a rationality fault, the VVT actual opening degree 110 and the VVT target opening degree 120 are compared by mathematical means to judge whether the engine VVT state 210 is a response delay fault or a target error fault.

[0076] Specifically, if the average deviation value is greater than the second threshold value 170 and less than the third threshold value 180, it is judged that the engine VVT state 210 is a response delay fault; if the average deviation value is greater than the third threshold value 180, it is judged that the engine VVT state 210 is a target error fault.

[0077] In this step, the fault type is distinguished by comparing the average deviation value with two preset threshold values, and other mathematical parameters can also be used for comparison and distinction.

[0078] S4, third comprehensive decision step 300;

[0079] In combination with more than three times of judgment completed by the second fault judgment step 200 within the preset time, the engine VVT final state 310 is diagnosed.

[0080] Specifically, if the number of times that the engine VVT state 210 is judged by the second fault judgment step 200 within the preset time to be a response delay fault or a target error fault exceeds the diagnosis preset value 320, the engine VVT final state 310 is diagnosed to be a response delay fault or a target error fault; if the engine is turned off during the second fault judgment step 200 or the third comprehensive decision step 300, the current fault diagnosis is interrupted.

[0081] In this step, the engine VVT final state diagnosis is given by using a repeated and comprehensive judgment method, and other methods combined with the last judgment of the second fault judgment step 200 can also be used, such as scoring each judgment of the second fault judgment step 200 and giving the engine VVT final state diagnosis after comprehensively scoring all scores.

[0082] Embodiment 2:

[0083] As shown in Figure 2 An engine fault diagnosis method, the specific steps are as follows:

[0084] S1, first information acquisition step 100;

[0085] S2, diagnosis triggering step 150;

[0086] Specifically, the specific method for judging whether the engine VVT has a rationality fault is as follows:

[0087] Let h(x) = |f(x) - g(x)|, where f(x) represents the actual opening degree of VVT, g(x) represents the target opening degree of VVT, and h(x) represents the absolute value of the difference between f(x) and g(x).

[0088] Within a preset time period t, if In the formula, θ2 is the second threshold value 170, then it is judged that the engine VVT state has a rationality fault, and the second fault judgment step 200 is started; otherwise, the second fault judgment step 200 is not started.

[0089] This step gives another implementation of the diagnosis triggering step 150, and of course the diagnosis triggering step 150 can also be implemented in other ways.

[0090] S3, second fault judgment step 200;

[0091] Specifically, in the second fault diagnosis step 200, the engine VVT ​​status 210 is determined to be either a slow response fault or a target error fault. The specific method is as follows:

[0092] Within a preset time period starting from a 120° change in the VVT ​​target opening, the preset time period t is divided into several time segments t′. n In time segment t′ n Calculate f′(x) for each time segment, and count the number of time segments where f′(x) ≠ 0 as a times, and the number of time segments where f′(x) = 0 as b times; if If θ3 is the third threshold 180, then the engine VVT ​​state 210 is determined to be a slow response fault; otherwise, the engine VVT ​​state 210 is determined to be a target error fault.

[0093] This step provides another implementation of the second fault determination step 200. Of course, the second fault determination step 200 can also be implemented in other ways.

[0094] S4, Third Comprehensive Decision-Making Step 300.

[0095] Example 3:

[0096] like Figure 3 As shown, an engine fault diagnosis device 600 is used for VVT fault diagnosis of engines in range-extended electric vehicles or plug-in hybrid electric vehicles. It includes a first information acquisition unit 610, a diagnosis trigger unit 615, a second fault judgment unit 620, and a third comprehensive decision unit 630. In this embodiment, the output terminal of the first information acquisition unit 610 is electrically connected to the diagnosis trigger unit 615, the diagnosis trigger unit 615 is electrically connected to the second fault judgment unit 620, and the second fault judgment unit 620 is electrically connected to the third comprehensive decision unit 630.

[0097] Furthermore, the first information acquisition unit 610 acquires, scans, or exchanges the actual VVT opening 110 and the target VVT opening 120;

[0098] In this embodiment, the first information acquisition unit sends the actual VVT opening 110 and the target VVT opening 120 to the diagnostic trigger unit 615, or it can directly send the actual VVT opening 110 and the target VVT opening 120 to the second fault judgment unit 620. The first information acquisition unit 610 can be a sensor, ECU, data interaction module, or other electronic structure that can obtain the actual VVT opening 110 and the target VVT opening 120. The first information acquisition unit 610 can be set locally in the vehicle, or it can be set on a cloud server or mobile terminal.

[0099] Further, the diagnosis triggering unit 615 judges whether the engine VVT state 210 has a rationality fault according to the VVT actual opening degree 110 and the VVT target opening degree 120 acquired, scanned or exchanged by the first information acquiring unit 610 when the VVT target opening degree 120 value changes.

[0100] Specifically, the diagnosis triggering unit 615 integrates the absolute value of the deviation value of the VVT actual opening degree 110 and the VVT target opening degree 120 in the time period when the absolute value of the difference value between the VVT target opening degree 120 value and the VVT lock position is greater than the first threshold 160, and then calculates the average deviation value of the integral in the unit time period; if the average deviation value of the unit time period is greater than the second threshold 170, it is judged that the engine VVT state 210 has a rationality fault, and the engine VVT state 210 is judged by the second fault judging unit 620; otherwise, it is judged that the engine VVT state 210 does not have a rationality fault.

[0101] As an alternative means of this embodiment, let f(x) represent the VVT actual opening degree, g(x) represent the VVT target opening degree, and h(x) = |f(x)-g(x)|; in a preset time period t, if In the formula, θ2 is the second threshold 170, and the diagnosis triggering unit 615 judges that the engine VVT state 210 has a rationality fault, which needs to be judged by the second fault judging unit 620; otherwise, the diagnosis triggering unit 615 judges that the engine VVT state 210 does not have a rationality fault.

[0102] In this embodiment, after the diagnosis triggering unit 615 judges whether the VVT system has a rationality fault according to the VVT target opening degree 120 and the VVT actual opening degree 110, the diagnosis triggering unit 615 sends the judgment result to the second fault judging unit 620 to further judge the fault type; of course, it is also possible not to judge through the diagnosis triggering unit 615, but to directly judge the fault type or no rationality fault through the second fault judging unit 620. The diagnosis triggering unit 615 can be a processor configured separately in the car, or the program can be directly written into the ECU, or it can be designed on the cloud or mobile terminal.

[0103] Further, when the engine VVT has a rationality fault, the second fault judging unit 620 compares the VVT actual opening degree 110 and the VVT target opening degree 120 by mathematical means to judge whether the engine VVT state 210 is a response delay fault or a target error fault.

[0104] Specifically, the second fault judgment unit 620 determines that the engine VVT ​​state 210 is a slow response fault when the average deviation value is greater than the second threshold 170 and less than the third threshold 180; and determines that the engine VVT ​​state 210 is a target error fault when the average deviation value is greater than the third threshold 180.

[0105] As an alternative to this embodiment, within a preset time period starting from the change in the VVT ​​target opening, the preset time period t is divided into several time segments t′. n In time segment t′ n Calculate f′(x) for each time segment, and count the number of time segments where f′(x) ≠ 0 as a times, and the number of time segments where f′(x) = 0 as b times; if Where θ3 is the third threshold 180, the second fault judgment unit 620 judges the engine VVT ​​state 210 as a slow response fault; otherwise, the second fault judgment unit 620 judges the engine VVT ​​state 210 as a target error fault.

[0106] In this embodiment, the second fault judgment unit 620 receives information sent by the diagnostic trigger unit 615 to further determine the fault type. The second fault judgment unit 620 can also directly receive information sent by the first information acquisition unit 610 to directly determine the fault type or whether there is no reasonable fault. In this embodiment, after making a judgment, the second fault judgment unit 620 sends the judgment result to the third comprehensive decision unit 630. Alternatively, the judgment made by the second fault judgment unit 620 can be directly used as the final diagnosis. The second fault judgment unit 620 can be a separately configured processor locally in the vehicle, or the program can be directly written into the EUC (Electronic Control Unit), or it can be designed to be located in the cloud or on a mobile terminal.

[0107] Furthermore, the engine fault diagnosis device 600 also includes a third integrated decision unit 630, which, in conjunction with the three or more judgments made by the second fault judgment unit 620 within a preset time, diagnoses the final state 310 of the engine VVT.

[0108] Specifically, within a preset time period, if the second fault judgment unit 620 determines that the engine VVT ​​state 210 is a slow response fault or a target error fault more than the number of times it determines that the engine VVT ​​state 210 is a slow response fault or a target error fault, the third comprehensive decision unit 630 diagnoses that the final state 310 of the engine VVT ​​is a slow response fault or a target error fault.

[0109] In this embodiment, the third integrated decision unit 630 can be a processor configured locally in the vehicle, or the program can be written directly into the EUC, or it can be designed to be on the cloud or a mobile terminal.

[0110] Similarly, a computer storage medium stores a plurality of computer programs, and a processor can execute the computer programs to implement the engine fault diagnosis method of any one of the above.

[0111] Similarly, a vehicle includes the above engine fault diagnosis device; and / or the above computer storage medium; the vehicle also includes a range-extending vehicle VVT engine or a plug-in hybrid vehicle VVT engine; the vehicle can also include other single operating condition VVT engines.

[0112] It should be noted that the above embodiments are only for more clearly illustrating the technical solutions of the present application, and those skilled in the art can understand that the embodiments of the present application are not limited to the above content, and the obvious changes, replacements or substitutions based on the above content do not exceed the scope of the technical solutions of the present application; other embodiments also fall within the scope of the present application without departing from the concept of the present application.

Claims

1. An engine failure diagnosis method characterized by comprising: The application discloses an engine VVT fault diagnosis method for a range-extended electric vehicle or a plug-in hybrid vehicle, which comprises a first information acquisition step (100) and a second fault judgment step (200). The first information acquisition step (100) is used for acquiring, scanning or exchanging a VVT actual opening degree (110) and a VVT target opening degree (120). The second fault judgment step (200) is used for comparing the VVT actual opening degree (110) and the VVT target opening degree (120) by means of mathematics when a rationality fault exists in the engine VVT, and judging whether the engine VVT state (210) is a response delay fault or a target error fault. The method further comprises a diagnosis triggering step (150) which is used for judging whether a rationality fault exists in the engine VVT according to the VVT actual opening degree (110) and the VVT target opening degree (120) acquired, scanned or exchanged by the first information acquisition step (100) and judging whether the VVT target opening degree (120) value changes. The specific method for judging whether a rationality fault exists in the engine VVT is as follows: when the absolute value of the difference between the VVT target opening degree (120) value and a VVT locking position is greater than a first threshold value (160), the absolute value of the deviation value of the VVT actual opening degree (110) and the VVT target opening degree (120) is integrated, and then the average deviation value of the integral in a unit time period is calculated; if the average deviation value in the unit time period is greater than a second threshold value (170), it is judged that the engine VVT state (210) has the rationality fault; otherwise, it is judged that the engine VVT state (210) does not have the rationality fault. The method further comprises a third comprehensive decision step (300) which is used for diagnosing a final engine VVT state (310) in combination with more than three times of judgment completed by the second fault judgment step (200) in a preset time.

2. The engine failure diagnosis method according to claim 1, characterized by, In the second fault judgment step, the specific method for judging whether the engine VVT state (210) is a response delay fault or a target error fault is as follows: if the average deviation value is greater than the second threshold value (170) and smaller than a third threshold value (180), it is judged that the engine VVT state (210) is the response delay fault; if the average deviation value is greater than the third threshold value (180), it is judged that the engine VVT state (210) is the target error fault.

3. The engine failure diagnostic method according to claim 1, characterized by, The third comprehensive decision step (300) is used for diagnosing the final engine VVT state (310), and the specific method is as follows: if the number of times that the engine VVT state (210) is judged to be the response delay fault or the target error fault by the second fault judgment step (200) in the preset time exceeds a diagnosis preset value (320), it is diagnosed that the final engine VVT state (310) is the response delay fault or the target error fault; if the engine is turned off in the process of the second fault judgment step (200) or the third comprehensive decision step (300), the present fault diagnosis is interrupted. The specific method for judging whether a rationality fault exists in the engine VVT is as follows: ​ 4. The engine failure diagnostic method of claim 2, wherein ​ ​ ​ 5. The engine failure diagnostic method according to claim 1, characterized by, ​ The deviation of the VVT actual opening degree (110) and the VVT target opening degree (120) is calculated, and if the integral of the deviation is greater than a second threshold value within a preset time period, it is determined that the engine VVT state has a rationality fault; otherwise, it is determined that the engine VVT state does not have a rationality fault.

6. The engine failure diagnostic method according to claim 5, characterized by, In the second fault judgment step (200), whether the engine VVT state (210) is a response delay fault or a target error fault is determined, and the specific method is: Within a preset time period from the start of the change of the VVT target opening degree (120), the VVT actual opening degree (110) is differentiated several times, and if the number of times of differentiation of the VVT actual opening degree (110) is less than a third threshold value (180), it is determined that the engine VVT state (210) is a response delay fault; otherwise, it is determined that the engine VVT state (210) is a target error fault.

7. An engine failure diagnosis apparatus (600) characterized by comprising: The engine VVT fault diagnosis for extended-range electric vehicles or plug-in hybrid vehicles includes a first information acquisition unit (610) and a second fault judgment unit (620), wherein The first information acquisition unit (610) acquires, scans or exchanges the VVT actual opening degree (110) and the VVT target opening degree (120); The second fault judgment unit (620) compares the VVT actual opening degree (110) and the VVT target opening degree (120) by mathematical means when the engine VVT has a rationality fault, and determines whether the engine VVT state (210) is a response delay fault or a target error fault; It also includes a diagnosis triggering unit (615) that determines whether the engine VVT has a rationality fault when the VVT target opening degree (120) value changes based on the VVT actual opening degree (110) and the VVT target opening degree (120) acquired, scanned or exchanged by the first information acquisition unit (610); The diagnosis triggering unit (615) integrates the absolute value of the deviation of the VVT actual opening degree (110) and the VVT target opening degree (120) when the absolute value of the difference between the VVT target opening degree (120) value and the VVT lock position is greater than a first threshold value (160), and then calculates the average deviation value of the integral in a unit time period; if the average deviation value in a unit time period is greater than a second threshold value (170), it is determined that the engine VVT state (210) has a rationality fault, and the engine VVT state (210) is determined by the second fault judgment unit (620); otherwise, it is determined that the engine VVT state (210) does not have a rationality fault.

8. The engine failure diagnosing apparatus (600) according to claim 7, characterized by It also includes a third comprehensive decision unit (630) that diagnoses the final state (310) of the engine VVT by combining more than three times of judgment completed by the second fault judgment unit (620) within a preset time.

9. The engine failure diagnosing apparatus (600) according to claim 7, characterized by The second fault judging unit (620) judges that the engine VVT state (210) is a response delay fault when the average deviation value is greater than the second threshold (170) and less than a third threshold (180), and judges that the engine VVT state (210) is a target error fault when the average deviation value is greater than the third threshold (180).

10. The engine failure diagnosing apparatus (600) according to claim 8, characterized by The third comprehensive decision unit (630) diagnoses that the engine VVT final state (310) is a response delay fault or a target error fault when the second fault judging unit (620) judges that the engine VVT state (210) is a response delay fault or a target error fault more than a diagnostic preset value (320) within a preset time.

11. The engine failure diagnosing apparatus (600) according to claim 7, characterized by The second fault judging unit (620) calculates the deviation of the VVT actual opening (110) and the VVT target opening (120), and judges that the engine VVT state is a reasonable fault when the integral of the deviation is greater than a second threshold within a preset time period, and judges that the engine VVT state is not a reasonable fault otherwise.

12. The engine failure diagnosing apparatus (600) according to claim 11, characterized by The second fault judging unit (620) judges that the engine VVT state (210) is a response delay fault when the number of times that the derivative of the VVT actual opening (110) is 0 is less than a third threshold (180) within a preset time period from the start of the change of the VVT target opening (120), and judges that the engine VVT state (210) is a target error fault otherwise.

13. A computer storage medium, characterized in that The storage medium stores a plurality of computer programs, and the processor can execute the computer programs to implement the engine fault diagnosis method according to any one of claims 1 to 6.

14. A vehicle characterized by comprising: The vehicle further comprises a range extended vehicle VVT engine or a plug-in hybrid vehicle VVT engine. The vehicle further comprises a range extended vehicle VVT engine or a plug-in hybrid vehicle VVT engine.

Images