Evaluation time processing method for misfire diagnosis

Abstract

The invention discloses an evaluation time processing method for misfire diagnosis, and the method comprises the steps: obtaining the operation time of each cylinder of an engine at a crankshaft operation angle as evaluation time, and solving an average value of the evaluation time; determining an evaluation time updating coefficient under the condition that the evaluation time updating optimization processing activation condition is met; determining final evaluation time according to the value of the flag bit and the evaluation time updating coefficient; determining the value of an initial flag bit of the fixed cylinder according to the characteristic coefficient and the self-learning correction coefficient; and determining the final evaluation time according to the value of the initial flag bit, the updated evaluation time updating coefficient and the evaluation time. According to the method provided by the invention, the evaluation time for misfire diagnosis is updated by considering the control deviation of different cylinder combustion systems of the engine after aging, so that the misfire diagnosis precision is improved.

Description

Technical Field

[0001] The invention relates to the technical field of engine control, and in particular to an evaluation time processing method for misfire diagnosis. Background Art

[0002] Engine misfire refers to the failure of the mixture to burn due to lack of ignition, too lean or too rich mixture, low compression stroke pressure or other reasons. Misfire monitoring is one of the difficulties and key points of OBD system diagnosis in the National V and National VI emission regulations for gasoline engines. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide an evaluation time processing method for misfire diagnosis in view of the deficiencies in the prior art. The method updates the evaluation time for misfire diagnosis by considering the control deviation of different cylinder combustion systems of the engine after aging, thereby improving the accuracy of misfire diagnosis.

[0004] To achieve the above object, according to one aspect of the present invention, there is provided an evaluation time processing method for misfire diagnosis, comprising:

[0005] Obtaining the running time of each cylinder of the engine at a crankshaft running angle as the evaluation time, and calculating the average value of the evaluation time of each cylinder of the engine in a number of consecutive sampling cycles;

[0006] When the evaluation time update optimization processing activation conditions are met, a fuel cut-off is requested for all cylinders of the engine. At this time, the engine is in the running process and the vehicle is in the coasting process. The evaluation area is divided according to the engine speed, and the evaluation time update coefficient is determined according to the evaluation area;

[0007] Determine the value of the evaluation time update optimization counter and the initial value of the evaluation time update coefficient according to the evaluation time update coefficient and the evaluation time average value;

[0008] Determine the value of the flag bit according to the value of the evaluation time update optimization counter; determine the updated evaluation time update coefficient according to the value of the flag bit, the initial value of the evaluation time update coefficient and the evaluation time update coefficient;

[0009] The final evaluation time is determined according to the value of the flag bit, the updated evaluation time update coefficient and the evaluation time.

[0010] In the above scheme, the running time of each cylinder of the engine in a crankshaft running angle is obtained as the evaluation time, and the method for obtaining the average evaluation time of each cylinder of the engine in a number of consecutive sampling periods is:

[0011] The crankshaft operation angle section is the crankshaft angle of each cylinder of the engine from 80° after the cylinder compression top dead center to 260° after the corresponding cylinder compression top dead center. The running time of each cylinder of the engine in the crankshaft operation angle section is obtained as the evaluation time. The evaluation time within a number of consecutive sampling periods is T n [0,1,2,3…], where n is the engine cylinder number; the default first value of the evaluation time is 0;

[0012] The average evaluation time of the evaluation time in several consecutive sampling periods is t RawSegmentAvg [0,1,2…], where t RawSegmentAvg [0] is the evaluation time average value of the first cylinder of the engine.

[0013] In the above scheme, the activation conditions of the evaluation time update optimization process include:

[0014] (1) The engine is in running state;

[0015] (2) All cylinders of the engine are in the fuel cut-off state;

[0016] (3) The engine does not directly participate in driving the vehicle;

[0017] (4) The engine does not experience knock or pre-ignition;

[0018] (5) The evaluation time in several consecutive sampling periods is not 0;

[0019] (6) The engine did not malfunction.

[0020] In the above solution, the engine not directly participating in driving the vehicle means that the engine is not connected to the transmission system.

[0021] In the above scheme, the method of dividing the evaluation area according to the engine speed is:

[0022] The engine speed is divided into 10 evaluation areas as follows:

[0023]

[0024] In the above scheme, the method for determining the evaluation time update coefficient according to the evaluation area is:

[0025] Each cylinder of the engine has an evaluation time update coefficient corresponding to each of the 10 evaluation areas; the evaluation time update coefficients of the 10 evaluation areas are r n [0,1,2…,9], where n is the engine cylinder number, which can be saved after the vehicle is powered off, and its initial value is 1.

[0026] In the above scheme, the method for determining the value of the evaluation time update optimization counter and the initial value of the evaluation time update coefficient is:

[0027] If the evaluation time update optimization processing activation condition is not met and the evaluation area changes, at least one of the two conditions is met, and the evaluation time update optimization counter Cnt is set. AdaptCounter Reset to 1 and update the evaluation time coefficient to the initial value r raw [0,1,2...] Reset to the evaluation time update coefficient r stored at power-down n The specific value of the evaluation time update coefficient of the current evaluation area in [0,1,2…,9]; where r raw [0] is the initial value of the evaluation time update coefficient of the first cylinder of the engine, r raw [1] is the initial value of the evaluation time update coefficient for the second cylinder of the engine, and so on;

[0028] If the evaluation time update optimization processing activation condition is not met and the evaluation area changes, the evaluation time update optimization counter Cnt is incremented after each sampling period of the evaluation time. AdaptCounter The value of is increased by 1, where the evaluation time updates the optimization counter Cnt AdaptCounter The default initial value is 0, and the initial value r of the evaluation time update coefficient is accumulated. raw [0,1,2…] as the new initial value of the evaluation time update coefficient; the accumulation method is as follows, taking the first cylinder of the engine as an example, and the other cylinders are similar:

[0029] The evaluation time update coefficient initial value of the first cylinder of the engine where r raw [0](z) is the initial value of the evaluation time update coefficient obtained in the previous sampling cycle, and Avg is the average value of the evaluation time average values ​​of all cylinders.

[0030] In the above scheme, the method for determining the value of the flag bit according to the value of the evaluation time update optimization counter is:

[0031] Determine whether the evaluation time in the current evaluation area has completed the first update. If the first update is not completed, the evaluation time is accumulated in a weighted manner. The purpose of this design is that when the first update is not completed, the learning parameters are not stable, and the weighted approach is more stable and accurate. If the evaluation time in the current evaluation area updates the optimization counter Cnt AdaptCounter The value is not less than the preset value Cnt A1 The number of times Cnt AdaptWeightCounter Greater than the preset number Cnt B1 , indicating that the evaluation time has just completed the first update, and the flag bit bFirstAdaptDone The value is 1; otherwise, the flag bit b FirstAdaptDone The value of is 0; wherein the number Cnt AdaptWeightCounter The value of is obtained by updating the cumulative method, and the updating cumulative method is: the number of times Cnt AdaptWeightCounter The default value is 0, and the optimization counter Cnt is updated at the evaluation time. AdaptCounter After reset, the evaluation time is accumulated again, and the optimization counter Cnt is updated. AdaptCounter Not less than the preset value Cnt A1 After that, the number of times Cnt AdaptWeightCounter The value of is added by 1, that is, the optimization counter Cnt is updated each time the evaluation is performed. AdaptCounter After reset, the evaluation time updates the optimization counter Cnt AdaptCounter Update at most once; the number Cnt AdaptWeightCounter and the flag bit b FirstAdaptDone The default value is 0, and it will be saved after the vehicle is powered off.

[0032] In the above scheme, the method for determining the updated evaluation time update coefficient is:

[0033] In the flag bit b FirstAdaptDone The value of is 0, and the evaluation time updates the optimization counter Cnt AdaptCounter The value is not less than the preset value Cnt A1 Only when the evaluation time update coefficient r is allowed to be updated n [0,1,2…,9]; the updating of the evaluation time update coefficient r n The method for [0,1,2…,9] is:

[0034] Taking the current evaluation area as 0 as an example, the methods for other evaluation areas are similar; update the evaluation time update coefficient r when the current evaluation area is 0 n [0] = k AdaptWeight × raw [n]+(1-k AdaptWeight )×r n [0](z); where r raw [n] is the initial value r of the evaluation time update coefficient raw The value of the n+1th cylinder in [0,1,2…]; where r n [0](z) is the specific value of the evaluation time update coefficient when the evaluation area is 0 in the previous sampling period; where k AdaptWeight is the weighting coefficient; similarly, the updated evaluation time update coefficients of other evaluation areas can be obtained, that is, the updated evaluation time update coefficient r n [0,1,2…,9];

[0035] In the flag bit b FirstAdaptDone When the value of is 1, and the evaluation time updates the optimization counter Cnt AdaptCounter The value is not less than the preset value Cnt A2 Only when the evaluation time update coefficient r is allowed to be updated n [0,1,2…,9], where Cnt A2 Not less than Cnt A1 ; The update of the evaluation time update coefficient r n The method for [0,1,2…,9] is:

[0036] Taking the current evaluation area as 0 as an example, the methods for other evaluation areas are similar; update the evaluation time update coefficient r when the current evaluation area is 0 n [0] = k Adapt × raw [n]+(1-k Adapt )×r n [0](z); where r raw [n] is the initial value r of the evaluation time update coefficient raw The value of the n+1th cylinder in [0,1,2…]; where r n [0](z) is the specific value of the evaluation time update coefficient when the evaluation area is 0 in the previous sampling period; where k Adapt is the weighting coefficient, and k Adapt No more than k AdaptWeight Similarly, the updated evaluation time update coefficients of other evaluation areas can be obtained, which are the updated evaluation time update coefficients r n [0,1,2…,9].

[0037] In the above scheme, the method for determining the final evaluation time is:

[0038] In the flag bit b FirstAdaptDone When the value of is 0, the final evaluation time T n-New is the evaluation time;

[0039] In the flag bit b FirstAdaptDone When the value of is 1, the final evaluation time T n-New It is the product of the evaluation time and the specific value of the updated evaluation time update coefficient in the current evaluation area.

[0040] The present invention provides an evaluation time processing method for misfire diagnosis. The method reads the evaluation time of all cylinders during the engine oil cut-off process, introduces an evaluation method coefficient, and optimizes and updates the final evaluation time for misfire diagnosis, thereby improving the accuracy of misfire diagnosis. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Also, throughout the accompanying drawings, the same reference figures are used to represent the same components. In the drawings:

[0042] Figure 1 The figure is a flow chart of a method for processing evaluation time for misfire diagnosis in an embodiment of the present invention. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0044] It should be understood that the size of the serial numbers of the steps in the embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0045] Example 1

[0046] The present application provides, on the one hand, a method for processing evaluation time for fire diagnosis, referring to Figure 1 ,include:

[0047] S1, obtaining the running time of each cylinder of the engine in a crankshaft running angle as the evaluation time, and calculating the average evaluation time of each cylinder of the engine in a number of consecutive sampling cycles.

[0048] Specifically, in this embodiment, the method for obtaining the running time of each cylinder of the engine in a crankshaft running angle is: a crankshaft running angle is a crankshaft angle of each cylinder of the engine from 80° after the compression top dead center of each cylinder to 260° after the compression top dead center of its corresponding cylinder, and the running time of each cylinder of the engine in this crankshaft running angle is obtained as the evaluation time, then the evaluation time within a number of consecutive sampling periods is T n [0, 1, 2, 3…], where n is the cylinder number; the default initial value of the evaluation time is 0; the evaluation time T n The values ​​of [0, 1, 2, 3…] will be continuously updated; n [0] represents the evaluation time of each cylinder of the engine at the current sampling, T n[1] represents the evaluation time of each cylinder of the engine in the last sampling, and so on. In particular, all sampling in the subsequent steps is that the crankshaft of each cylinder rotates from 80° after the compression top dead center to 260° after the compression top dead center, that is, the crankshaft rotates 180°.

[0049] In this embodiment, the number of engine cylinders is 4, and the evaluation time average value t of each cylinder of the engine in 10 consecutive sampling cycles is calculated. RawSegmentAvg [0,1,2,3], where t RawSegmentAvg [0] is the evaluation time average of the first cylinder of the engine, and so on.

[0050] S2: When the evaluation time update optimization processing activation conditions are met, a fuel cut-off request is made to all cylinders of the engine, an evaluation area is divided according to the engine speed, and an evaluation time update coefficient is determined according to the evaluation area.

[0051] Specifically, in this embodiment, the evaluation time update optimization processing activation conditions include:

[0052] (1) The engine is in operation;

[0053] (2) All cylinders of the engine are in the fuel cut-off state;

[0054] (3) The engine is not directly involved in driving the vehicle, that is, the engine is not connected to the transmission system;

[0055] (4) The engine does not experience knock or pre-ignition;

[0056] (5) The evaluation time in 10 consecutive sampling periods is not 0;

[0057] (6) The engine did not malfunction.

[0058] In this embodiment, the update checking cycle of judging the activation conditions of the evaluation time update optimization process is 10 ms, and the fuel cut-off request for all cylinders of the engine can be made only when the activation conditions of the evaluation time update optimization process are met.

[0059] Specifically, in this embodiment, the evaluation area is divided according to the engine speed, and the method for determining the evaluation time update coefficient according to the evaluation area is:

[0060] The engine speed is divided into 10 evaluation areas as follows:

[0061]

[0062] Each cylinder of the engine has a specific value of the evaluation time update coefficient in each of the 10 evaluation areas. The evaluation time update coefficients of the 10 evaluation areas are r n[0,1,2…,9], where n is the engine cylinder number, which can be saved after the vehicle is powered off, and its initial value is 1. Specifically, if the engine speed is 750 rpm or less, the current evaluation area is 0, if the engine speed is greater than 750 rpm and not less than 1000 rpm, the current evaluation area is 1, and so on.

[0063] S3, determining the value of the evaluation time update optimization counter and the initial value of the evaluation time update coefficient according to the evaluation time update coefficient and the evaluation time average value.

[0064] Specifically, in this embodiment, if the evaluation time update optimization processing activation condition is not met and the evaluation area changes, at least one of the two conditions is met, the evaluation time update optimization counter Cnt is set to AdaptCounter Reset to 1 and update the evaluation time coefficient to the initial value r raw [0,1,2,3] Reset to the evaluation time update coefficient r stored at power-off n The specific value of the evaluation time update coefficient of the current evaluation area in [0,1,2…,9]; where r raw [0] is the initial value of the evaluation time update coefficient of the first cylinder of the engine, r raw [1] is the initial value of the evaluation time update coefficient for the second cylinder of the engine, and so on.

[0065] If the evaluation time update optimization processing activation condition is not met and the evaluation area changes, the evaluation time update optimization counter Cnt is incremented after each sampling period of the evaluation time. AdaptCounter The value of is increased by 1, where the evaluation time updates the optimization counter Cnt AdaptCounter The default initial value is 0, and the initial value r of the cumulative evaluation time update coefficient raw [0,1,2,3] is used as the initial value of the new evaluation time update coefficient; the accumulation method is as follows, taking the first cylinder of the engine as an example, and the other cylinders are similar:

[0066] Initial value of evaluation time update coefficient for engine cylinder 1 where r raw [0](z) is the initial value of the evaluation time update coefficient obtained in the previous sampling period, t RawSegmentAvg [0] is the average evaluation time of the first cylinder of the engine, and Avg is the average evaluation time of all cylinders, that is,

[0067]

[0068] S4, determining the value of the flag bit according to the value of the evaluation time update optimization counter; determining the updated evaluation time update coefficient according to the value of the flag bit, the initial value of the evaluation time update coefficient and the evaluation time update coefficient.

[0069] Specifically, in this embodiment, if the evaluation time in the current evaluation area updates the optimization counter Cnt AdaptCounter The value is not less than the preset value Cnt A1 The number of times Cnt AdaptWeightCounter Greater than the preset number Cnt B1 , indicating that the evaluation time has just completed the first update, and the flag bit b FirstAdaptDone The value is 1; otherwise, the flag bit b FirstAdaptDone The value of is 0; in this embodiment, the preset value Cnt A1 The preset number is 5, Cnt B1 is 3.

[0070] Among them, the number of times Cnt AdaptWeightCounter The value is obtained by updating the cumulative method, and the updating cumulative method is: times Cnt AdaptWeightCounter The default value is 0, and the optimization counter Cnt is updated at the evaluation time. AdaptCounter After reset, the counter Cnt is accumulated again and the evaluation time is updated and optimized. AdaptCounter Not less than the preset value Cnt A1 After, the number of times Cnt AdaptWeightCounter The value of is increased by 1, that is, the optimization counter Cnt is updated every time the evaluation is performed AdaptCounter After reset, the evaluation time updates the optimization counter Cnt AdaptCounter Update at most once; the number of times is Cnt AdaptWeightCounter and flag bit b FirstAdaptDone The default value is 0, and it will be saved after the vehicle is powered off.

[0071] In the flag bit b FirstAdaptDone The value is 0, and the evaluation time updates the optimization counter Cnt AdaptCounter The value is not less than the preset value Cnt A1 Only when the evaluation time update coefficient r is allowed to be updated n [0,1,2…,9]; Update evaluation time update coefficient r n The method for [0,1,2…,9] is:

[0072] Taking the current evaluation area as 0 as an example, the methods for other evaluation areas are similar; update the evaluation time update coefficient r when the current evaluation area is 0 n [0] = k AdaptWeight × raw [n]+(1-k AdaptWeight )×r n [0](z); where r raw [n] is the initial value of the evaluation time update coefficient r raw The value of the n+1th cylinder in [0,1,2,3]; where rn [0](z) is the specific value of the evaluation time update coefficient when the evaluation area is 0 in the previous sampling period (i.e., the evaluation time update coefficient r n When the evaluation area is 0 in [0,1,2,...,9], r n [0]); where k AdaptWeight is the weighting coefficient, which is 0.15 in this example; similarly, the updated evaluation time update coefficients of other evaluation areas can be obtained, that is, the updated evaluation time update coefficient r n [0,1,2…,9].

[0073] In the flag bit b FirstAdaptDone When the value is 1, the evaluation time updates the optimization counter Cnt AdaptCounter The value is not less than the preset value Cnt A2 Only when the evaluation time update coefficient r is allowed to be updated n [0,1,2…,9], where Cnt A2 Not less than Cnt A1 In this embodiment, Cnt A2 =16; Update evaluation time update coefficient r n The method for [0,1,2…,9] is:

[0074] Taking the current evaluation area as 0 as an example, the methods for other evaluation areas are similar; update the evaluation time update coefficient r when the current evaluation area is 0 n [0] = k Adapt × raw [n]+(1-k Adapt )×r n [0](z); where r raw [n] is the initial value of the evaluation time update coefficient r raw The value of the n+1th cylinder in [0,1,2,3]; where r n [0](z) is the specific value of the evaluation time update coefficient when the evaluation area is 0 in the previous sampling period (i.e., the evaluation time update coefficient r n When the evaluation area is 0 in [0,1,2,...,9], r n [0]); where k Adapt is the weighting coefficient, which is 0.005 in this example, and k Adapt No more than k AdaptWeight Similarly, the updated evaluation time update coefficients of other evaluation areas can be obtained, which is the updated evaluation time update coefficient r n [0,1,2…,9].

[0075] S5, determining the final evaluation time according to the value of the flag bit, the updated evaluation time update coefficient and the evaluation time.

[0076] Specifically, in this embodiment, the method for determining the final evaluation time is:

[0077] In the flag bit b FirstAdaptDone When the value is 0, the final evaluation time T n-New is the evaluation time T n [0,1,2,3…];

[0078] In the flag bit b FirstAdaptDone When the value is 1, the final evaluation time T n-New is the evaluation time T n [0,1,2,3…] multiplied by the updated evaluation time update coefficient in the current evaluation area.

[0079] The final evaluation time of each cylinder of the engine is obtained and used for misfire evaluation of each cylinder.

[0080] In summary, the evaluation time processing method for misfire diagnosis provided by the present invention updates the evaluation time for misfire diagnosis by considering the control deviation of different cylinder combustion systems of the engine after aging, thereby improving the accuracy of misfire diagnosis.

[0081] It should be pointed out that, according to the needs of implementation, the various steps described in this application can be divided into more steps, or two or more steps or partial operations of the steps can be combined into a new step to achieve the purpose of the present invention.

[0082] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for evaluating time processing for misfire diagnosis, characterized in that: include: Obtaining the running time of each cylinder of the engine at a crankshaft running angle as the evaluation time, and calculating the average value of the evaluation time of each cylinder of the engine in a number of consecutive sampling cycles; When the evaluation time update optimization processing activation conditions are met, a fuel cut-off is requested for all cylinders of the engine, an evaluation area is divided according to the engine speed, and an evaluation time update coefficient is determined according to the evaluation area; Determine the value of the evaluation time update optimization counter and the initial value of the evaluation time update coefficient according to the evaluation time update coefficient and the evaluation time average value; Determine the value of the flag bit according to the value of the optimization counter updated during the evaluation time; Determine an updated evaluation time update coefficient according to the value of the flag bit, the initial value of the evaluation time update coefficient and the evaluation time update coefficient; The final evaluation time is determined according to the value of the flag bit, the updated evaluation time update coefficient and the evaluation time.

2. The evaluation time processing method for misfire diagnosis according to claim 1, characterized in that: The method of obtaining the running time of each cylinder of the engine at a crankshaft running angle as the evaluation time and obtaining the average value of the evaluation time of each cylinder of the engine in a number of consecutive sampling periods is as follows: The crankshaft operation angle section is the crankshaft angle of each cylinder of the engine from 80° after the cylinder compression top dead center to 260° after the corresponding cylinder compression top dead center. The running time of each cylinder of the engine in the crankshaft operation angle section is obtained as the evaluation time. The evaluation time within a number of consecutive sampling periods is T n [0,1,2,3…], where n is the engine cylinder number; the default first value of the evaluation time is 0; The average evaluation time of the evaluation time in several consecutive sampling periods is t RawSegmentAvg [0,1,2…], where t RawSegmentAvg [0] is the evaluation time average value of the first cylinder of the engine.

3. The evaluation time processing method for misfire diagnosis according to claim 2, characterized in that: The method of dividing the evaluation area according to the engine speed is as follows: The engine speed is divided into the following 10 evaluation areas. When the engine speed is 750rpm, 1000rpm, 1500rpm, 2000rpm, 2500rpm, 3000rpm, 3500rpm, 4000rpm, 4500rpm, and 5000rpm, respectively, the evaluation areas correspond to 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9.

4. The evaluation time processing method for misfire diagnosis according to claim 3, characterized in that: The method for determining the evaluation time update coefficient according to the evaluation area is: Each cylinder of the engine has an evaluation time update coefficient corresponding to each of the 10 evaluation areas; the evaluation time update coefficients of the 10 evaluation areas are r n [0,1,2…,9], where n is the engine cylinder number, which can be saved after the vehicle is powered off, and its initial value is 1.

5. The evaluation time processing method for misfire diagnosis according to claim 4, characterized in that: The method for determining the value of the evaluation time update optimization counter and the initial value of the evaluation time update coefficient is: If the evaluation time update optimization processing activation condition is not met and the evaluation area changes, at least one of the two conditions is met, and the evaluation time update optimization counter Cnt is set. AdaptCounter Reset to 1 and update the evaluation time coefficient to the initial value r raw [0,1,2...] Reset to the evaluation time update coefficient r stored at power-down n The specific value of the evaluation time update coefficient of the current evaluation area in [0,1,2…,9]; where r raw [0] is the initial value of the evaluation time update coefficient of the first cylinder of the engine, r raw [1] is the initial value of the evaluation time update coefficient for the second cylinder of the engine, and so on; If the evaluation time update optimization processing activation condition is not met and the evaluation area changes, the evaluation time update optimization counter Cnt is incremented after each sampling period of the evaluation time. AdaptCounter The value of is increased by 1, where the evaluation time updates the optimization counter Cnt AdaptCounter The default initial value is 0, and the initial value r of the evaluation time update coefficient is accumulated. raw [0,1,2…] as the new initial value of the evaluation time update coefficient; the accumulation method is as follows, taking the first cylinder of the engine as an example, and the other cylinders are similar: The evaluation time update coefficient initial value of the first cylinder of the engine where r raw [0](z) is the initial value of the evaluation time update coefficient obtained in the previous sampling cycle, and Avg is the average value of the evaluation time average values ​​of all cylinders.

6. The evaluation time processing method for misfire diagnosis according to claim 5, characterized in that: The method for determining the value of the flag bit according to the value of the optimization counter updated during the evaluation time is as follows: If the evaluation time in the current evaluation area updates the optimization counter Cnt AdaptCounter The value is not less than the preset value Cnt A1 The number of times Cnt AdaptWeightCounter Greater than the preset number Cnt B1 , indicating that the evaluation time has just completed the first update, and the flag bit b FirstAdaptDone The value of is 1; Otherwise, flag bit b FirstAdaptDone The value of is 0; wherein the evaluation time updates the optimization counter Cnt AdaptCounter The value is not less than the preset value Cnt A1 The number of times Cnt AdaptWeightCounter The value of is obtained by updating the cumulative method, and the updating cumulative method is: the number of times Cnt AdaptWeightCounter The default value is 0, and the optimization counter Cnt is updated at the evaluation time. AdaptCounter After reset, the evaluation time is accumulated again, and the optimization counter Cnt is updated. AdaptCounter Not less than the preset value Cnt A1 After that, the number of times Cnt AdaptWeightCounter The value of is added by 1, that is, the optimization counter Cnt is updated each time the evaluation is performed. AdaptCounter After reset, the evaluation time updates the optimization counter Cnt AdaptCounter Update at most once; the number Cnt AdaptWeightCounter and the flag bit b FirstAdaptDone The default value is 0, and it will be saved after the vehicle is powered off.

7. The evaluation time processing method for misfire diagnosis according to claim 6, characterized in that: The method for determining the updated evaluation time update coefficient is: In the flag bit b FirstAdaptDone The value of is 0, and the evaluation time updates the optimization counter Cnt AdaptCounter The value is not less than the preset value Cnt A1 Only when the evaluation time update coefficient r is allowed to be updated n [0,1,2…,9]; the updating of the evaluation time update coefficient r n The method for [0,1,2…,9] is: Taking the current evaluation area as 0 as an example, the methods for other evaluation areas are similar; update the evaluation time update coefficient r when the current evaluation area is 0 n [0] = k AdaptWeight × raw [n]+(1-k AdaptWeight )×r n [0](z); where r raw [n] is the value of the n+1th cylinder in the initial value rraw[0,1,2…] of the evaluation time update coefficient; n [0](z) is the specific value of the evaluation time update coefficient when the evaluation area is 0 in the previous sampling period; where k AdaptWeight is the weighting coefficient; similarly, the updated evaluation time update coefficients of other evaluation areas can be obtained, that is, the updated evaluation time update coefficient r n [0,1,2…,9]; In the flag bit b FirstAdaptDone When the value of is 1, and the evaluation time updates the optimization counter Cnt AdaptCounter The value is not less than the preset value Cnt A2 Only when the evaluation time update coefficient r is allowed to be updated n [0,1,2…,9], where Cnt A2 Not less than Cnt A1 ; The update of the evaluation time update coefficient r n The method for [0,1,2…,9] is: Taking the current evaluation area as 0 as an example, the methods for other evaluation areas are similar; update the evaluation time update coefficient r when the current evaluation area is 0 n [0] = k Adapt × raw [n]+(1-k Adapt )×r n [0](z); where r raw [n] is the value of the n+1th cylinder in the initial value rraw[0,1,2…] of the evaluation time update coefficient; n [0](z) is the specific value of the evaluation time update coefficient when the evaluation area is 0 in the previous sampling period; where k Adapt is the weighting coefficient, and k Adapt No more than k AdaptWeight Similarly, the updated evaluation time update coefficients of other evaluation areas can be obtained, which is the updated evaluation time update coefficient r n [0,1,2…,9].

8. The evaluation time processing method for misfire diagnosis according to claim 7, characterized in that: The method for determining the final evaluation time is: In the flag bit b FirstAdaptDone When the value of is 0, the final evaluation time T n-New is the evaluation time; In the flag bit b FirstAdaptDone When the value of is 1, the final evaluation time T n-New It is the product of the evaluation time and the specific value of the updated evaluation time update coefficient in the current evaluation area.

9. The method for identifying dynamic fuel cut-off of an engine according to claim 1, characterized in that: The evaluation time update optimization processing activation conditions include: (1) The engine is in running state; (2) All cylinders of the engine are in the fuel cut-off state; (3) The engine does not directly participate in driving the vehicle; (4) The engine does not experience knock or pre-ignition; (5) The evaluation time in several consecutive sampling periods is not 0; (6) The engine did not malfunction.

10. The method for identifying dynamic fuel cut-off of an engine according to claim 9, characterized in that: The engine not directly participating in driving the vehicle means that the engine is not connected to the transmission system.

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