A method, device and medium for multi-dimensional identification of engine combustion failure

Abstract

The present invention discloses a method, device, and medium for multi-dimensionally identifying engine combustion failure. The method includes: when an engine combustion failure judgment enabling condition is met, performing an engine combustion failure judgment: when an activation condition of a first method for identifying engine combustion failure is met, detecting the cylinder number of the combustion failure using the first method; when an activation condition of a second method for identifying engine combustion failure is met, detecting the cylinder number of the combustion failure using the second method; and jointly determining the cylinder number of the combustion failure using the cylinder number detected by the first method and the cylinder number detected by the second method. The present invention improves the accuracy of engine combustion failure judgment by combining different methods to perform engine combustion failure judgment, thereby reminding the driver to perform timely maintenance and inspection to protect the engine.

Description

Technical Field

[0001] The present invention relates to the field of engine control technology, and in particular to a method, device and medium for multi-dimensionally identifying engine combustion failure. Background Art

[0002] If engine combustion failure is not identified in time, it will have adverse consequences on engine power, emissions, and economy. Therefore, it is necessary to diagnose and identify whether the engine has combustion failure, so as to remind the driver to carry out timely maintenance and inspection to protect the engine in time. Summary of the Invention

[0003] The purpose of the present invention is to provide a method, device and medium for multi-dimensionally identifying engine combustion failure, which is used to identify whether the engine has combustion failure from multiple dimensions, thereby reminding the driver to perform timely maintenance and inspection to protect the engine.

[0004] To achieve the above objectives, according to a first aspect of the present invention, a multi-dimensional method for identifying engine combustion failure is provided, the method comprising:

[0005] When the engine combustion failure judgment enabling conditions are met, the engine combustion failure judgment is performed:

[0006] When the activation condition of the first method for identifying engine combustion failure is met, detecting the cylinder number of the combustion failure by the first method for identifying engine combustion failure;

[0007] When the activation condition of the second method for identifying engine combustion failure is met, detecting the cylinder number of the combustion failure by the second method for identifying engine combustion failure;

[0008] The cylinder number detected by the first method for identifying engine combustion failure and the cylinder number detected by the second method for identifying engine combustion failure are used together to determine the cylinder number of the engine combustion failure.

[0009] In the above scheme, the engine combustion failure judgment enabling conditions include:

[0010] (1) Enter the fire diagnosis area specified in the regulations;

[0011] (2) No fuel cut-off request;

[0012] (3) The gear position has not changed, and the first time after the gear position changes is delayed;

[0013] (4) The clutch is in a fully engaged state, and the clutch is delayed for a second time after being fully engaged;

[0014] (5) Non-uneven road surface;

[0015] (6) The water temperature is within the preset range;

[0016] (7) The throttle opening fluctuates within a certain range;

[0017] (8) The engine is in running state;

[0018] When all of the above conditions are met, the engine combustion failure judgment enabling condition is met.

[0019] In the above scheme, the activation condition of the first method for identifying engine combustion failure is determined by the average engine speed and the average engine intake air density; wherein the average engine speed and the average engine intake air density are respectively the average of the engine speed and the engine intake air density during the current sampling period and several previous sampling periods;

[0020] If the activation condition of the first method for identifying engine combustion failure in the current sampling period is not satisfied, the first method for identifying engine combustion failure is not activated;

[0021] If the activation conditions of the first method for identifying engine combustion failure in the current sampling period are met, and the activation conditions of the first method for identifying engine combustion failure in the previous sampling periods are all met, then the first method for identifying engine combustion failure is activated;

[0022] In other cases, the first method of identifying engine combustion failure is not activated;

[0023] The activation conditions of the second method for identifying engine combustion failure are similar.

[0024] In the above solution, the first method for identifying engine combustion failure includes:

[0025] Obtain the operating time of each cylinder of the engine at a specific crankshaft operating angle, and calculate the average operating time of each cylinder of the engine over several consecutive sampling periods;

[0026] Divide the evaluation area according to the engine speed and determine the evaluation time update coefficient of each cylinder of the engine in each evaluation area;

[0027] Determining whether activation conditions for engine combustion failure identification evaluation time update optimization processing are met; if not, maintaining the evaluation time update coefficients of each cylinder of the engine in each evaluation area unchanged; if so, determining the value of the evaluation time update optimization counter, and determining an initial value of the evaluation time update coefficient based on the evaluation time update coefficient and the average value of the operating time;

[0028] Determine the value of the flag bit according to the value of the evaluation time update optimization counter, and 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;

[0029] Determine a final running time according to the value of the flag bit, the updated evaluation time update coefficient, and the running time;

[0030] Calculating an average value of the final operating time of each cylinder of the engine within a plurality of consecutive sampling periods according to the final operating time, and determining a maximum value and a minimum value of the average value of the final operating time;

[0031] determining a value of an initial flag indicating whether combustion of a fixed cylinder has failed according to a maximum value and a minimum value of the final running time average value;

[0032] determining a value of a flag indicating whether combustion of a fixed cylinder has failed according to the value of the initial flag indicating whether combustion of the fixed cylinder has failed;

[0033] According to the value of the flag bit of whether the fixed cylinder combustion fails or not, the value of the final flag bit of whether the fixed cylinder combustion fails or not is determined, and finally the cylinder number of the combustion failure is obtained.

[0034] In the above solution, the specific crankshaft operating angle is the crankshaft angle from 80° after the compression top dead center of each cylinder of the engine to 260° after the compression top dead center of its corresponding cylinder;

[0035] The activation conditions for the updated optimization processing of the engine combustion failure identification evaluation time include:

[0036] (1) The engine is in running state;

[0037] (2) The engine did not experience combustion failure at this time;

[0038] (3) All cylinders of the engine are in the fuel cut-off state;

[0039] (4) The engine does not directly participate in driving the vehicle;

[0040] (5) The engine does not experience knock or pre-ignition;

[0041] (6) The running time of each cylinder of the engine is not zero in several consecutive sampling periods;

[0042] (7) The engine has no malfunction;

[0043] When all the above conditions are met, the activation conditions for the engine combustion failure identification evaluation time update optimization process are met.

[0044] In the above solution, determining the value of the evaluation time update optimization counter and determining the initial value of the evaluation time update coefficient according to the evaluation time update coefficient and the average value of the running time include:

[0045] If any of the following conditions is met, the value of the evaluation time update optimization counter is reset to 1, and the initial value of the evaluation time update coefficient of each cylinder of the engine is reset to the evaluation time update coefficient within the current evaluation area:

[0046] (1) The activation conditions for the engine combustion failure identification evaluation time update optimization process are not met;

[0047] (2) Changes in the current evaluation area;

[0048] If both of the above conditions are not met, the value of the evaluation time update optimization counter is increased by 1 after each sampling period, and the initial value of the evaluation time update coefficient is accumulated at the same time. The accumulation method is as follows:

[0049] For each cylinder of the engine, calculate the quotient of its running time average value and the average of the running time average values ​​of all cylinders of the engine in each sampling period, add the initial value of the evaluation time update coefficient accumulated in the previous sampling period to the reciprocal of the quotient to obtain the initial value of the evaluation time update coefficient accumulated in the current sampling period;

[0050] Determining a flag value according to a value of an evaluation time update optimization counter, and determining an updated evaluation time update coefficient according to the flag value, the evaluation time update coefficient initial value, and the evaluation time update coefficient, including:

[0051] If the value of the evaluation time update optimization counter of the current evaluation area is not less than the preset value Cnt A1 The number of times Cnt AdaptWeightCounter Greater than the preset number Cnt B1 , then the flag value is 1; otherwise the flag value is 0; where, the number of times Cnt AdaptWeightCounter The accumulation method is: after the value of the optimization counter of the evaluation time of the current evaluation area is reset, it is accumulated again. If the value of the optimization counter of the evaluation time of the current evaluation area is not less than the preset value Cnt A1 , then the number Cnt AdaptWeightCounter Add 1; every time the evaluation time of the current evaluation area is updated and the optimization counter value is reset, the number of times Cnt AdaptWeightCounter Accumulate at most once;

[0052] When the flag value is 0 and the value of the evaluation time update optimization counter of the current evaluation area is not less than the preset value Cnt A1, updating the evaluation time update coefficient by calculating, for a cylinder in the current evaluation area, the product of the initial value of the evaluation time update coefficient and the first weighting coefficient, and simultaneously calculating the difference between 1 and the first weighting coefficient and the product of the difference and the evaluation time update coefficient corresponding to the cylinder in the current evaluation area; the sum of the two products is the updated evaluation time update coefficient;

[0053] When the flag value is 1 and the value of the evaluation time update optimization counter of the current evaluation area is not less than the preset value Cnt A2 , updating the evaluation time update coefficient by calculating, for a cylinder in the current evaluation area, the product of the initial value of the evaluation time update coefficient and the second weighting coefficient, and simultaneously calculating the difference between 1 and the second weighting coefficient and the product of the difference and the evaluation time update coefficient corresponding to the cylinder in the current evaluation area, the sum of the two products being the updated evaluation time update coefficient; wherein both the first weighting coefficient and the second weighting coefficient are less than 1, and the second weighting coefficient is not greater than the first weighting coefficient;

[0054] Determining a final running time according to the value of the flag bit, the updated evaluation time update coefficient, and the running time includes:

[0055] When the flag value is 0, the running time of each cylinder of the engine is the final running time;

[0056] When the value of the flag bit is 1, the product of the running time of each cylinder of the engine and the corresponding updated evaluation time update coefficient is the final running time.

[0057] In the above solution, determining the value of the initial flag indicating whether combustion of a fixed cylinder has failed or not based on the maximum and minimum values ​​of the final running time average value includes:

[0058] Determining a characteristic coefficient according to the maximum and minimum values ​​of the final running time average values ​​includes:

[0059] Get the maximum value T of the final running time average value in the current sampling period Max With the minimum value T Min , and calculate the corresponding intermediate value

[0060] Similarly, calculate the intermediate values ​​corresponding to several sampling periods before the current sampling period, and finally calculate the average value of all intermediate values, which is the characteristic coefficient;

[0061] Determining the value of an initial flag indicating whether the fixed cylinder has failed combustion based on the characteristic coefficient and a preset threshold coefficient for determining whether the fixed cylinder has failed combustion includes:

[0062] If 1 plus k AdaptIf the characteristic coefficient of the fixed cylinder is greater than or equal to the preset threshold coefficient for judging whether the fixed cylinder combustion fails, the value of the initial flag bit of whether the fixed cylinder combustion fails is 1, otherwise it is 0;

[0063] Among them, k Adapt is a self-learning correction coefficient. The threshold coefficient used to determine combustion failure in a fixed cylinder is determined by the average engine speed and the average engine intake air density. The average engine speed and the average engine intake air density are the average values ​​of the engine speed and the engine intake air density in the current sampling period and the previous sampling periods, respectively.

[0064] Determining the value of the flag bit indicating whether combustion of the fixed cylinder has failed according to the value of the initial flag bit indicating whether combustion of the fixed cylinder has failed includes:

[0065] On the premise that the value of the initial flag bit of the fixed cylinder combustion failure is 1, if:

[0066] Case 1: Determine the cylinder number whose final running time average is equal to the maximum value;

[0067] Case 2: If a cylinder meets the following conditions, its cylinder number is determined: first, the difference between the maximum value and the average value of the final operating time of the cylinder is calculated, and then the quotient of the difference and the maximum value is calculated. The quotient is greater than zero and less than the preset value X;

[0068] Case 3: The cylinder meeting Case 1 or Case 2 meets the following conditions: First, all running times and all final running times of the cylinder meeting Case 1 or Case 2 within a number of consecutive sampling periods are calculated, and the differences between them and the maximum value are then calculated. The quotient of these differences and the maximum value is within a preset range of -Y to Y, where Y is a preset value.

[0069] The fourth case: at least one cylinder does not meet the first or the second case;

[0070] Case 5: The following situation exists: When the cylinder numbers that meet the first or second conditions are recorded according to the cylinder working order, the number of cylinders that do not meet the first or second conditions between two consecutive cylinder numbers that meet the first or second conditions is not less than 2, and the cylinder number equal to the minimum value is not the next working cylinder number after the cylinder number that meets the first or second conditions;

[0071] If the first case, the second case, the third case, the fourth case, and the fifth case are multiple sampling times Cnt CynOffDelay If both of the above conditions are met, it indicates that the cylinder meeting the first condition or the second condition has combustion failure, and the flag bit b corresponding to whether the cylinder combustion fails or not is set.CynOff Set to 1, otherwise 0;

[0072] Determining the value of the final flag bit of whether the fixed cylinder combustion fails according to the value of the flag bit of whether the fixed cylinder combustion fails, and finally obtaining the cylinder number of the combustion failure, including:

[0073] Actively cut off fuel for the cylinders that meet the first or second conditions, and re-obtain the final average running time T of each cylinder of the engine in the fuel cut-off state n_AvgNew and the maximum value T of the average final running time of each cylinder of the engine in the fuel cut-off state maxNew With the minimum value T minNew ;

[0074] (1) For flag bit b CynOff The value of the cylinder is 1, if and When the fixed cylinder combustion failure of this cylinder is the final flag position, that is, the fuel cut flag position b CynOffFuelCut =b CynOff =1, and the multiple sampling times Cnt CynoffDelay Subtract 1 and save after power off, the self-learning correction coefficient k Adapt Remain unchanged; among them, T n_Avg is the average final operating time of the nth cylinder of the engine, and C1 is the preset value;

[0075] (2) For flag bit b CynOff The value of the cylinder is 1, if and If only one of the following is met, the oil cut-off flag of this cylinder is b CynOffFuelCut =0, the number of multiple sampling times Cnt CynoffDelay Remain unchanged; the self-learning correction coefficient And save it after power off;

[0076] (3) For flag bit b CynOff The value of the cylinder is 1, if and If all of the above are not satisfied, the oil cut-off flag of this cylinder is set to b. CynOffFuelCut =0, the multiple sampling times Cnt CynoffDelay Add 2, the self-learning correction coefficient And save it after power off;

[0077] (4) For flag bit b CynOff The cylinder with a value of 0, if the final running time average value of the cylinder T m_Avg satisfy Then the oil cut-off flag of this cylinder is b CynOffFuelCut =0, the number of multiple sampling times CntCynoffDelay Remain unchanged, the self-learning correction coefficient And save after power off; C2 is the preset value;

[0078] (5) In other cases, the cylinder oil cut-off mark is b CynOffFuelCut =0, the number of multiple sampling times Cnt CynoffDelay and the self-learning correction coefficient k Adapt remain unchanged;

[0079] If the value of the initial flag is 1, the fuel cut flag of the engine cylinder b CynOffFuelCut =1, it means that the cylinder of the engine has a real fuel cut-off, that is, combustion failure.

[0080] In the above scheme, the update method of the preset values ​​X and Y is:

[0081] 1) At the oil cut-off mark position b of the cylinder CynOffFuelCut When it is 1, the preset values ​​X and Y under the corresponding cylinder are updated accordingly. The update method is:

[0082] X=X(z)+0.02

[0083] Y=Y(z)+0.01

[0084] Where X(z) and Y(z) are the preset values ​​X and Y after the last update; the preset values ​​X and Y for other cylinders are not updated;

[0085] 2) At the oil cut-off mark position b of the cylinder CynOffFuelCut When it is 0, the corresponding cylinder b will be accumulated CynOffFuelCut The number of times CNT is 0 is increased by 1 each time. It is updated only once when the active fuel cut-off condition is met. Once CNT is not less than the preset value Z, the following will be done:

[0086] X=X(z)-0.007

[0087] Y=Y(z)-0.005

[0088] After the update is completed, CNT is cleared to 0 until the next active oil cut-off condition is met and the oil cut-off flag bit b of the same cylinder is judged again. CynOffFuelCut Is it 0? If it is 0, then increase the number of times CNT under the corresponding cylinder by 1 again;

[0089] In other cases:

[0090] X=X(z)

[0091] Y = Y(z);

[0092] Active fuel cut-off conditions include:

[0093] 1) The engine combustion failure judgment enabling conditions are met;

[0094] 2) The vehicle speed exceeds the preset value;

[0095] 3) The engine does not experience knock and pre-ignition;

[0096] 4) The exhaust temperature does not exceed the preset protection temperature;

[0097] 5) GPF does not request active regeneration;

[0098] 6) The oxygen storage capacity of the catalyst does not exceed the preset coefficient of its total oxygen storage capacity;

[0099] 7) No failure of fuel injection system related components occurs;

[0100] 8) The difference between the current average engine speed and the average engine speed obtained when determining the threshold coefficient for determining combustion failure in a fixed cylinder is within a preset range;

[0101] 9) The difference between the current average engine intake air density and the average engine intake air density obtained when determining the threshold coefficient for determining combustion failure in a fixed cylinder is within a preset range;

[0102] When all the above conditions are met, the active fuel cut-off condition is met; and only when the active fuel cut-off condition is met, the active fuel cut-off is performed on the cylinder that meets the first condition or the second condition.

[0103] In the above scheme, the second method for identifying engine combustion failure includes:

[0104] Get the running time of each tooth of the engine crankshaft flywheel;

[0105] determining a starting crankshaft angle and tooth length for estimating engine combustion torque, determining an evaluation window for estimating engine combustion torque based on the starting crankshaft angle and tooth length, and obtaining an array of operating times of each tooth within the evaluation window in combination with the operating times of each tooth;

[0106] Filter the running time array of each tooth and output the filtered running time array of each tooth;

[0107] Estimating the engine speed based on the filter running time array of each tooth to obtain an engine speed array;

[0108] estimating the initial torque difference value of each tooth based on the engine speed during the operation of each tooth, and obtaining an array of initial torque difference values;

[0109] Filtering the initial value array of the torque difference of each tooth and outputting the filtered torque difference array of each tooth;

[0110] Calculating a total torque variation within the evaluation window based on the filtered torque difference array of each tooth;

[0111] The cylinder number of the combustion failure is determined according to the total torque change.

[0112] In the above solution, obtaining the running time of each tooth of the engine crankshaft flywheel includes:

[0113] The running time of each tooth refers to the time it takes for the engine flywheel to go from the current tooth to the next tooth when the engine is running; for a missing tooth, the average running time of the teeth before and after the missing tooth is taken as the running time of the missing tooth;

[0114] Determining a starting crankshaft angle and tooth length for estimating engine combustion torque, determining an evaluation window for estimating engine combustion torque based on the starting crankshaft angle and tooth length, and obtaining an array of operating times of each tooth within the evaluation window in combination with the operating time of each tooth, including:

[0115] Starting crankshaft angle phi Start The method for determining phi is: Start =f1(n,rho)+b CatHeat ×f2(n,rho); where b CatHeat The catalyst light-off control is activated. CatHeat is 1, otherwise it is 0; f1(n,rho) and f2(n,rho) are calibration values, which are determined by the engine speed n and the density of fresh air entering the cylinder rho: After the catalyst is ignited, the calibration value f1(n,rho) and the first tooth length Cnt are calibrated ToothArrayLen1 , calibrate the calibration value f2(n,rho) and the second tooth length Cnt during the catalyst light-off process ToothArrayLen2 ,The calibration is determined based on: the difference between the combustion torque when the engine fails to burn and the combustion torque when there is no combustion failure within the evaluation window meets the preset requirements;

[0116] An evaluation window for estimating the engine combustion torque is determined based on the starting crankshaft angle and the tooth length, and the evaluation window and the running time array t of the four consecutive teeth after the evaluation window are obtained by combining the running time of each tooth. ToothTimes [0,1,2,...,Cnt ToothArrayLen +3]; in which, when the catalyst is not in the ignition state or the ignition state is completed, the tooth length Cnt ToothArrayLen =Cnt ToothArrayLen1 ; When the catalyst is ignited, the tooth length Cnt ToothArrayLen =Cnt ToothArrayLen2 ;

[0117] Filter the running time array of each tooth and output the filtered running time array of each tooth, including:

[0118] Calculate the initial value of the filter time t for the running time of each tooth ToothTimesFilterRaw [N]:

[0119] t ToothTimesFilterRaw [N] = r1 × t ToothTimes [N]+r2×t ToothTimes [N-1]+r3×t ToothTimes [N-2]

[0120] Where N is the running time array t ToothTimes [0,1,2,...,Cnt ToothArrayLen +3]; when N=0 or 1, t ToothTimesFilterRaw [0] = t ToothTimes [0], t ToothTimesFilterRaw [1] = t ToothTimes [0]; r1, r2, and r3 are weighting coefficients, the sum of which is 1. The method for determining the weighting coefficients is as follows: the difference between the combustion torque when the engine fails to burn and the combustion torque when there is no combustion failure within the evaluation window meets the preset requirements;

[0121] Determine the filter run time t for each tooth ToothTimesFilter [N] = t ToothTimesFilterRaw [N+2], get the filter running time array t for each tooth ToothTimesFilter [0,1,2,...,Cnt ToothArrayLen +1];

[0122] The engine speed is estimated based on the filter running time array of each tooth to obtain the engine speed array, including:

[0123] Calculating engine speed Where C1 is the coefficient;

[0124] Get the engine speed array n EstRpm [0,1,2,...,Cnt ToothArrayLen +1];

[0125] The initial torque difference value of each tooth is estimated based on the engine speed during the operation of each tooth, and an array of initial torque difference values ​​is obtained, including:

[0126] Calculate the initial value M of the torque difference of each tooth EstTrqErrRaw [N]=C2×[(n EstRpm [N]) 2 -(n EstRpm [N-1]) 2 ]; where C2 is the coefficient;

[0127] Get the torque difference initial value array M EstTrqErrRaw [0,1,2,...,Cnt ToothArrayLen +1];

[0128] Filter the initial value array of the torque difference of each tooth and output the filtered torque difference array of each tooth, including:

[0129] Similar to the running time array filtering, the filtered torque difference array M is obtained EstTrqErr [0,1,2,...,Cnt ToothArrayLen -1].

[0130] In the above solution, the total torque variation within the evaluation window is calculated based on the filtered torque difference array of each tooth, including:

[0131] The filtered torque difference array M EstTrqErr [0,1,2,...,Cnt ToothArrayLen -1] are added together to get the total torque change M TrqDetectDelta ;

[0132] Determining the cylinder number of the combustion failure according to the total torque change includes:

[0133] The total torque change M TrqDetectDelta Filter to obtain the total torque change M after filtering TrqSumMeanNew :

[0134] M TrqSumMeanNew =(1-r TrqWeightMean )×M TrqSumMean (z)+r TrqWeightMean ×M TrqDetectDelta

[0135] Where M T rq S um M ean(z) is the total torque change after filtering in the previous sampling period; r TrqWeightMean is the total torque variation filter coefficient;

[0136] Calculate the initial value S of the torque characteristic value used to evaluate whether the combustion torque is abnormal TrqDetectRaw :

[0137] S TrqDetectRaw =(1-r TrqWeightVar )×S TrqDetectRaw (z)+r TrqWeightVar ×(M TrqDetectDelta -M TrqSumMeanNew ) 2

[0138] Among them, S T rqD etect R aw(z) is the initial value of the torque characteristic value in the previous sampling period; r TrqWeightVar is the initial value filter coefficient of the torque characteristic value, and the calculation method is:

[0139] r TrqWeightVar =(1-k TrqWeightVar )×r TrqWeightVar (z)+k TrqWeightVar ×(r TrqWeightGain ×b TrqDetectErr (z)+r TrqWeightInc )

[0140] Among them, r T rq W eight V ar(z) is the initial value filter coefficient of the torque characteristic value in the previous sampling period; k TrqWeightVar is the update coefficient; r TrqWeightGain is the gain coefficient; r TrqWeightInc is the cumulative coefficient; b TrqDetectErr (z) is the flag indicating whether the engine combustion torque is abnormal in the previous sampling period. If it is abnormal, it is set to 1; if it is not abnormal, it is set to 0;

[0141] The initial value of the torque characteristic value S TrqDetectRaw Filter and obtain the filtered torque characteristic value S TrqDetect :

[0142] S TrqDetect =(1-r TrqWeightVarFilt )×S TrqDetect (z)+r TrqWeightVar ×S TrqDetectRaw

[0143] Among them, S T rq D etect(z) is the total torque change after filtering in the previous sampling period; r TrqWeightVarFilt is the filtering coefficient of the torque characteristic value after filtering;

[0144] Determine the combustion torque abnormality judgment lower limit value M TrqBoundLower :

[0145]

[0146] Among them, k BunndLower is the coefficient of deviation of the lower limit;

[0147] Calculate the torque deviation M used to determine whether the engine combustion torque is abnormal ErrEst :

[0148] M ErrEst=M TrqDetectDelta -M TrqBoundLower

[0149] Determine whether the engine combustion torque is normal:

[0150] If M appears ErrEst <M ErrThresh , then b TrqDetectErr Set to 1, the engine combustion torque is abnormal; otherwise b TrqDetectErr is 0, and the engine combustion torque is normal; ErrThresh is the combustion torque deviation limit;

[0151] Determine the cylinder number where combustion failed:

[0152] If b TrqDetectErr If set to 1, the cylinder number in the power stroke under the corresponding evaluation window is read, indicating that the corresponding cylinder has combustion failure.

[0153] In the above solution, the difference between the combustion torque when the engine fails to burn and the combustion torque when there is no combustion failure within the evaluation window meets the preset requirements, including:

[0154] The difference between the combustion torque when the combustion failure occurs and the combustion torque when there is no combustion failure is divided by the combustion torque when there is no combustion failure to obtain a ratio;

[0155] If the absolute value of the average value of the ratio exceeds the preset ratio threshold, the preset requirement is met.

[0156] In the above solution, the cylinder number detected by the first method for identifying engine combustion failure and the cylinder number detected by the second method for identifying engine combustion failure are used together to determine the cylinder number of the engine combustion failure, including:

[0157] If the cylinder number detected by the first method for identifying engine combustion failure is the same as the cylinder number detected by the second method for identifying engine combustion failure, combustion failure occurs in the corresponding cylinder; and combustion failure fault judgment for the corresponding cylinder will not be performed in subsequent vehicle driving cycles until the diagnostic instrument clears the fault.

[0158] If the first method for identifying engine combustion failure detects the cylinder number of combustion failure, but the second method for identifying engine combustion failure does not detect combustion failure on the same cylinder number, and the number of driving cycles that occur exceeds the preset number A, it is characterized as combustion failure, and the combustion torque deviation limit M of the corresponding cylinder under the second method for identifying engine combustion failure is set to ErrThresh Updated to the first multiple; and in subsequent vehicle driving cycles, the corresponding cylinder combustion failure fault judgment will not be performed until the diagnostic instrument clears the fault and then the combustion failure fault judgment will be performed again;

[0159] If the first method for identifying engine combustion failure detects a cylinder number with combustion failure, but the second method for identifying engine combustion failure does not detect combustion failure in the same cylinder number, and the number of driving cycles in which the combustion failure occurs does not exceed the preset number A, then the combustion failure is indicated as being in a pending state, and the threshold coefficient for determining fixed cylinder combustion failure for the corresponding cylinder under the first method for identifying engine combustion failure is updated to the second multiple, and is updated at most once per driving cycle, and combustion failure fault determination for the corresponding cylinder is still performed in subsequent vehicle driving cycles;

[0160] If the second method for identifying an engine combustion failure detects a cylinder number with combustion failure, but the first method for identifying an engine combustion failure does not detect combustion failure in the same cylinder number, and the number of driving cycles in which combustion failure occurs exceeds a preset number B, then combustion failure is indicated, and the threshold coefficient for determining fixed cylinder combustion failure for the corresponding cylinder under the first method for identifying an engine combustion failure is updated to a third multiple, and combustion failure fault determination for the corresponding cylinder is not performed in subsequent vehicle driving cycles until the diagnostic instrument clears the fault, at which time combustion failure fault determination is performed again;

[0161] If the second method for identifying engine combustion failure detects the cylinder number of combustion failure, but the first method for identifying engine combustion failure does not detect combustion failure on the same cylinder number, and the number of driving cycles that occur does not exceed the preset number B, then the combustion failure is indicated as pending, and the combustion torque deviation limit M of the corresponding cylinder under the second method for identifying engine combustion failure is set to ErrThresh The update is a multiple of four and is updated at most once per driving cycle, and the corresponding cylinder combustion failure fault judgment is still performed in subsequent vehicle driving cycles;

[0162] If the first method for identifying engine combustion failure and the second method for identifying engine combustion failure do not detect the same cylinder number, combustion failure fault judgment is still performed in the subsequent vehicle driving cycle;

[0163] Among them, the preset number B is greater than or equal to the preset number A, the first multiple is greater than the third multiple and greater than 1, and the second multiple is less than the fourth multiple and less than 1.

[0164] According to a second aspect of the present invention, an electronic device is provided, comprising: a storage device for storing executable instructions; a processing device for executing the executable instructions stored in the storage device, to implement the multi-dimensional identification method for determining engine combustion failure as described in any of the above technical solutions.

[0165] According to a third aspect of the present invention, a storage medium is provided, in which a computer program is stored. When the computer program is executed, the method for multi-dimensionally identifying engine combustion failure described in any of the above technical solutions is implemented.

[0166] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0167] The present invention selects different methods to identify and judge engine combustion failure under different working conditions, that is, the cylinder number detected by the first method for identifying engine combustion failure and the cylinder number detected by the second method for identifying engine combustion failure are jointly determined to determine the cylinder number of the engine combustion failure, and if the judgment results are different, the judgment threshold is continuously updated, thereby improving the accuracy of engine combustion failure judgment, thereby reminding the driver to carry out timely maintenance and inspection to protect the engine.

[0168] In addition, in the first method for identifying engine combustion failure, the preset value X in the second case, the preset value Y in the third case, and the self-learning correction coefficient are all updated over time, thereby improving the judgment accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0169] Figure 1 A flowchart of a method for multi-dimensionally identifying engine combustion failure provided by an embodiment of the present invention;

[0170] Figure 2 A flow chart of a first method for identifying engine combustion failure provided by an embodiment of the present invention;

[0171] Figure 3 A flow chart of a second method for identifying engine combustion failure provided by an embodiment of the present invention;

[0172] Figure 4 A schematic structural diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0173] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only intended to illustrate 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 may be combined with each other as long as they do not conflict with each other.

[0174] The embodiment of the present invention provides a multi-dimensional method for identifying engine combustion failure. Figure 1 shown.

[0175] In order to ensure the accuracy of the engine combustion failure judgment method, it needs to be carried out under certain conditions. Determine the enabling conditions of the engine combustion failure judgment method (the enabling condition judgment sampling period in this example is 10ms):

[0176] (1) Enter the fire diagnosis area specified in the regulations;

[0177] (2) No fuel cut-off request;

[0178] (3) The gear position has not changed, and a delay of 0.1s is required after the gear position changes to activate the engine combustion failure judgment method;

[0179] (4) The clutch is in a fully engaged state, and the engine combustion failure judgment method can only be activated after a delay of 1 second after the clutch is engaged;

[0180] (5) Non-uneven road surface;

[0181] (6) The water temperature is within the preset range and is higher than -6°C;

[0182] (7) The throttle opening fluctuation is small during the diagnosis process (the difference between the maximum and minimum throttle openings within 0.1s is less than 15%);

[0183] (8) The engine is in running state.

[0184] When all of the above conditions are met, the engine combustion failure detection enable condition is met. After all of the above conditions have been met for a certain period of time, the engine combustion failure detection can be performed. If the above conditions are not met, the vehicle's operating conditions may cause a false engine combustion failure detection.

[0185] Figure 2 This is the first method for identifying engine combustion failure. As shown in Table 1, it is primarily determined by the average engine speed and the average engine intake air density, primarily tested and verified on an engine test bench through active forced fuel cutoff. The average engine speed and average intake air density are the averages of the current sampling cycle and the previous four, for a total of five sampling cycles, and are therefore updated in real time. The sampling cycle is 180° of crankshaft rotation, and for each cylinder, the crankshaft angle is from 80° after the compression top dead center of each cylinder to 260° after the compression top dead center of its corresponding cylinder. The test verification results of this example are shown in Table 1.

[0186] Table 1 Activation table of the first method for identifying engine combustion failure

[0187]

[0188]

[0189] When the above is equal to 0, it means that the method is not activated; when it is equal to 1 and the first 8 sampling periods are not 0, it means that the method is activated; in other cases, it means that the method is not activated.

[0190] CN202010204064.9 "A gasoline engine misfire monitoring method" proposes to calculate the engine's running time within a certain crankshaft angle range near the compression top dead center of each cylinder and store it in an array. n [0,1,2,3…], where n is the cylinder number. However, as the life cycle of the engine combustion system progresses, the operating time may shift under different cylinders and different operating conditions, resulting in a decrease in the accuracy of combustion failure diagnosis. The present invention uses the operating time (combustion failure identification evaluation time) T n Update processing optimization is carried out to improve the accuracy of combustion failure diagnosis.

[0191] The first method to identify engine combustion failure, such as Figure 2 Shown, including:

[0192] The first step is to calculate the running time T of each cylinder n [0, 1, 2, 3…] and the corresponding cylinder's previous A times (A is 9 in this example), totaling A+1 times (10 times in this example). Since the engine in this example has 4 cylinders, for the sake of convenience, the following examples are all based on a 4-cylinder engine. The method for engines with other cylinder numbers is the same. Based on this, the average running time of each cylinder is formed. RawSegmentAvg [0,1,2,3], for example, t RawSegmentAvg [0] is the average time for the first cylinder, and so on. It is important to note that the default initial value for the first A run times is 0. The run time update cycle (sampling period) is 180° of crankshaft rotation, and each cylinder is from 80° of crankshaft angle after the compression top dead center of each cylinder to 260° after the compression top dead center of its corresponding cylinder.

[0193] The second step involves optimizing the combustion failure identification evaluation time and activating the conditional judgment method. In this example, the conditional judgment update check cycle is 10ms. This process can only be performed when all of the following conditions are met. This occurs primarily when all cylinders of the engine request fuel cutoff. This occurs while the engine is running and the vehicle is coasting. The conditions for this update are:

[0194] (1) The engine is in running state;

[0195] (2) No combustion failure was detected;

[0196] (3) All cylinders of the engine are in the fuel cut-off state;

[0197] (4) The engine is not directly involved in driving the vehicle, that is, the engine is not connected to the transmission system;

[0198] (5) The engine does not experience knock or pre-ignition;

[0199] (6) The running time of each cylinder of the engine in several consecutive sampling periods is not zero, that is, the A+1 running time of each cylinder calculated in the first step is not zero;

[0200] (7) There was no engine failure.

[0201] If all the above conditions are met, proceed to the third step, otherwise the update coefficient r of the combustion failure identification evaluation time is n [0,1,2,...,9] remain unchanged. After entering the third step, the update period (sampling period) in all steps is 180° of crankshaft rotation. For each cylinder, the update period is from 80° after the compression top dead center of each cylinder to 260° after the compression top dead center of its corresponding cylinder.

[0202] The third step is to determine the update array for combustion failure identification evaluation time update optimization. That is, the evaluation time update coefficient is stored in different areas. The area division depends on the engine speed, that is, the storage address of the update coefficient is different at different engine speeds. n [0,1,2,...], which is saved after the vehicle is powered off, and its initial value is 1. Here, r1[0,1,2,...] is the evaluation time update coefficient for cylinder 1. In this example, 10 regions are divided according to engine speed. Therefore, the evaluation time update coefficient for cylinder 1 is r1[0,1,2,...,9], and the same applies to other cylinders. Specifically, in this example, 10 regions are divided according to engine speed, as shown in Table 2.

[0203] Table 2 Evaluation area division table

[0204]

[0205] If the engine speed is 750 rpm or less, the evaluation region is 0; if the engine speed is greater than 750 rpm and less than 1000 rpm, the evaluation region is 1, and so on. It should be noted that in this example, each speed range (i.e., evaluation region) of each cylinder stores an evaluation time update coefficient, and its initial value is 1.

[0206] Step 4: Determine the combustion failure identification evaluation time and update the optimized counter Cnt AdaptCounter and the final evaluation time update coefficient initial value r raw [0,1,2,3].

[0207] If any of the following conditions are met, Cnt AdaptCounterReset to 1 and update the evaluation time coefficient to its initial value r raw [0,1,2,3](where r raw [0] is the initial value of the evaluation time update coefficient of the first cylinder, and so on) is reset to the update coefficient r1[0,1,2,...,9] stored at power-off, which is the same as the update coefficient of the current actual evaluation area:

[0208] (1) The activation conditions for the optimization process of combustion failure identification evaluation time update are not met;

[0209] (2) The evaluation area changes.

[0210] If the above two conditions are not met, Cnt AdaptCounter Add 1 and accumulate the evaluation time to update the initial value r of the coefficient raw [0,1,2,3], the accumulation method is as follows, taking the first cylinder as an example, the other cylinders are the same:

[0211] where r raw [0](z) is the initial value of the cumulative evaluation time update coefficient obtained in the previous sampling period, That is the average running time of all cylinders.

[0212] Step 5: Determine the evaluation time update coefficient r for combustion failure identification evaluation time update optimization n [0,1,2,...,9]. The bit in the evaluation time update coefficient array is stored corresponding to the current evaluation area.

[0213] 1) Determine whether the evaluation time for the current evaluation area has completed its first update. If the first update has not yet been completed, the evaluation time is accumulated using a weighted approach. This design aims to prevent the learning parameters from being unstable when the first update is not completed, making the weighted approach more stable and accurate.

[0214] If the combustion failure identification evaluation time in the current evaluation area is updated, the optimized counter Cnt AdaptCounter Not less than the preset value Cnt A1 (This example takes 5) the number of times Cnt AdaptWeightCounter Greater than the preset number Cnt B1 (3 in this example), the evaluation time is updated for the first time, that is, the flag bit b FirstAdaptDone is 1; otherwise, flag bit b FirstAdaptDone is 0.

[0215] Among them, the number of times Cnt AdaptWeightCounter The update accumulation method is: its default value is 0, in the counter Cnt AdaptCounterAfter reset, re-accumulate and update the optimized counter Cnt AdaptCounter Not less than the preset value Cnt A1 After that, the counter Cnt AdaptWeightCounter Add 1. That is, each time the counter Cnt AdaptCounter After reset, Cnt AdaptCounter Update at most once.

[0216] It should be noted that the number Cnt AdaptWeightCounter and flag bit b FirstAdaptDone It will be saved after the vehicle is powered off, and its default value is 0.

[0217] 2) In flag bit b FirstAdaptDone When it is 0, the counter Cnt optimized for combustion failure identification evaluation time update AdaptCounter Not less than the preset value Cnt A1 Only when the evaluation time update coefficient r is updated is it allowed to update n [0,1,2,...,9]. Otherwise, in the flag bit b FirstAdaptDone When it is 0, the evaluation time update coefficient r is not allowed to be updated n [0,1,2,...,9]. In the flag bit b FirstAdaptDone When it is 0, the counter Cnt optimized for combustion failure identification evaluation time update AdaptCounter Not less than the preset value Cnt A1 When the evaluation time update coefficient r is updated n The update method for [0,1,2,...,9] is:

[0218] Assume that the current evaluation area is 0. If it is in other evaluation areas, the update method is similar. Update the update coefficient r under the current evaluation area n :

[0219] r n [0] = k AdaptWeight ×r raw [n]+(1-k AdaptWeight )×r n [0](z)

[0220] Among them, 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], r n [0](z) is the update coefficient of the evaluation area 0 in the previous sampling period (i.e., the evaluation time update coefficient r n [0,1,2,...,9] when the evaluation area is 0 n [0], the default value for the first time is described above. )k AdaptWeight is the weighting coefficient, which is 0.15 in this example.

[0221] Based on the above rules, it can be determined that if the current evaluation area is in other areas, the update coefficient r n , which forms r n [0,1,2,...,9].

[0222] 3) In the flag bit b FirstAdaptDone When it is 1, the counter Cnt of combustion failure identification evaluation time update optimization AdaptCounter Not less than the preset value Cnt A2 Time (where Cnt A2 Not less than Cnt A1 The main purpose is to make the evaluation time more stable and the update speed can be slower. In this example, 16) is used to allow the evaluation time update coefficient r to be updated. n [0,1,2,...,9]. Otherwise, in the flag bit b FirstAdaptDone When it is 1, the evaluation time update coefficient r is not allowed to be updated n [0,1,2,...,9]. In the flag bit b FirstAdaptDone When it is 1, the counter Cnt of combustion failure identification evaluation time update optimization AdaptCounter Not less than the preset value Cnt A2 When the evaluation time update coefficient r is updated n The update method for [0,1,2,...,9] is:

[0223] Assume that the current evaluation area is 0. If it is in other evaluation areas, the update method is similar. Update the update coefficient r under the current evaluation area n :

[0224] r n [0] = k Adapt ×r raw [n]+(1-k Adapt )×r n [0](z)

[0225] Among them, 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], r n [0](z) is the update coefficient of the evaluation area 0 in the previous sampling period (i.e., the evaluation time update coefficient r n [0,1,2,...,9] is the evaluation area of ​​​​0 when r n [0], the default value for the first time is described above)k Adapt is the weighting coefficient, k Adapt No more than k AdaptWeight , k Adapt In this example, 0.005 is used.

[0226] Based on the above rules, it can be determined that if the current evaluation area is in other areas, the update coefficient r n , which forms r n [0,1,2,...,9].

[0227] The sixth step is to determine the final evaluation time for combustion failure identification.

[0228] 1) In the flag bit b FirstAdaptDone When it is 0, T n [0,1,2,3…] is the final evaluation time T for combustion failure identification n-New [0,1,2,3…];

[0229] 2) In flag bit b FirstAdaptDone When T is 1, n [0,1,2,3…] multiplied by the update coefficient r n [0,1,2,...,9] The value in the current evaluation area is the final evaluation time T for combustion failure identification n-New [0,1,2,3…]. Assuming the evaluation area is 0, the final evaluation time T for combustion failure diagnosis is n-New [0,1,2,3…]=T n [0,1,2,3…]*r n [0], used for combustion failure evaluation of each cylinder.

[0230] The seventh step is to calculate the average operating time of each cylinder within N consecutive time periods (5 in this example), and calculate each cylinder separately to form the average operating time of each cylinder T n_Avg :

[0231]

[0232] Step 8: Find the maximum value of the average running time T Max and the minimum value T Min .

[0233] T Max =max(T 1_Avg , T 2_Avg , T 3_Avg , T 4_Avg )

[0234] T Min =min(T 1_Avg , T 2_Avg , T 3_Avg , T 4_Avg )

[0235] Step 9: Determine the initial flag position b of whether the fixed cylinder combustion fails (continuous oil cutoff) CynOffRaw .

[0236] 1) Determine the characteristic coefficient r used to determine combustion failure in a fixed cylinder CynDetectRaw :Get the current sampling period The average value of the five sampling periods and the four sampling periods before it is the characteristic coefficient r CynDetectRaw .

[0237] 2) If r CynDetectRaw (1+k Adapt )≥r CynDetectOffLim , initial flag bit b C yn O ff R aw is 1; otherwise the initial flag bit b C yn O ff R aw is 0. Where k Adapt It is the self-learning correction coefficient, which will be saved after the vehicle is powered off. Its default initial value is 0; CynDetectOffLim The threshold coefficient for determining combustion failure in a fixed cylinder is determined by the average engine speed and the average engine intake density, where the average engine speed and the average engine intake density are respectively the average values ​​of the current sampling period and the previous four sampling periods, a total of five sampling periods. CynDetectOffLim The details can be obtained from the bench calibration.

[0238] Step 10: Determine whether the fixed cylinder combustion fails or not. CynOff .

[0239] In the initial flag b CynOffRaw If the value is 1, then:

[0240] (1) Read T n_Avg Which cylinder's average operating time is equal to T Max If they are equal, determine the cylinder number;

[0241] (2) If T Max With T n_Avg The difference between the average operating time of the cylinder and divided by T Max The coefficient obtained is greater than 0 but less than the preset value X. X will be saved after the vehicle is powered off and continuously updated. Its default value in this example is 0.08. Determine the cylinder number.

[0242] (3) T corresponding to the cylinder number that meets the first or second situation n [0], T n [1], T n [2], Tn [3], T n [4], T n_New [0], T n_New [1], T n_New [2], T n_New [3], T n_New Any value in [4] and T Max The difference, and divided by T Max The coefficients obtained are all within the preset range ±Y, where Y will be saved after the vehicle is powered off and continuously updated. In this example, Y is 0.08;

[0243] 4) At least one cylinder does not meet the first or the second condition;

[0244] 5) The cylinder numbers that appear in the first or second case are recorded according to the cylinder working order. If there are two cylinder numbers that meet the first or second case consecutively, the number of cylinders that do not meet the first or second case is not less than 2, and the cylinder number T in this case is n_Avg With T Min The cylinder number that is equal is not the next working cylinder number of the cylinder number that appears in the first or second case. For example, suppose the engine is a 4-cylinder engine, and the cylinder working order is 1-3-4-2-1-3-4-2-..., the cylinder numbers that meet the first or second case are cylinder 1 and cylinder 2, and the middle working cylinders are cylinder 3 and cylinder 4, then the T corresponding to cylinder 4 is 4_Avg Not equal to T Min .

[0245] When the above five conditions are met at the same time, and the number of multiple sampling times Cnt CynOffDelay If all of the above five conditions are met, it indicates that the cylinder in the first or second case has combustion failure (or continuous fuel cutoff). CynOff Equal to 1; flag bit b of other cylinders CynOff Equal to 0. Sampling times Cnt CynOffDelay It can be saved after the vehicle is powered off, and its initial default value is 8. Among them, the first case must be met.

[0246] Step 11: Output the final fuel cut-off flag bit b CynOffFuelCut .

[0247] In order to further clarify whether continuous oil cut-off actually occurs, when the following active oil cut-off conditions are met, the oil is actively cut off for the cylinders that meet the first or second conditions at the same time.

[0248] 1) The enabling conditions of the continuous oil cut-off verification method have not been exited and are always met;

[0249] 2) The vehicle speed exceeds a preset value (25 km / h in this example);

[0250] 3) The engine does not experience knock and pre-ignition;

[0251] 4) The exhaust temperature does not exceed the preset protection temperature, which is 950°C in this example;

[0252] 5) GPF does not request active regeneration;

[0253] 6) The oxygen storage capacity of the catalyst as a percentage of its total oxygen storage capacity does not exceed a preset coefficient, which in this example is 0.9;

[0254] 7) No failure of fuel injection system related components occurs;

[0255] 8) The difference between the average engine speed and the average engine speed obtained in step 9 is within a preset range, in this example ±20 rpm, where the average engine speed is the average of the current sampling period and the four sampling periods before it, for a total of five sampling periods;

[0256] 9) The difference between the average engine intake air density and the average intake air density obtained in step 9 is within a preset range, which in this example is ±15 rpm, where the average engine intake air density is the average of the current sampling period and the four sampling periods before it, a total of five sampling periods.

[0257] When all the above conditions are met, the cylinders that meet the first or second conditions are actively cut off from fuel: the new average final operating time T of each cylinder is obtained again according to the above method. n_AvgNew and the maximum value of the final operating time average value T MaxNew and the minimum value T MinNew .

[0258] if:

[0259] 1)b CynOff Under the cylinder with a value equal to 1, and When C1 is set to 0.08 in this example, the corresponding cylinder lower b CynOffFuelCut Equal to b CynOff , which is 1, and the sampling times Cnt CynOffDelay -1, (which is limited to a minimum value of 3) and saved after power off. Adapt Remain unchanged.

[0260] 2)b CynOff Under the cylinder with a value equal to 1, and When at least one of them is not satisfied, the corresponding cylinder b CynOffFuelCut Equal to 0. Set the sampling frequency Cnt CynOffDelay remains unchanged (it is limited to a minimum value of 3), And save the configuration after powering off.

[0261] 3)b CynOff =1 for the cylinder, otherwise, the sampling times Cnt CynOffDelay +2, (which is limited to a maximum value of 15), corresponding to the cylinder b CynOffFuelCut Equal to 0, and And save the configuration after powering off.

[0262] 4)b CynOff Under the cylinder with a value of 0, T m_Avg (Assume that the m cylinder corresponds to b CynOff =0) and the average cylinder operation time T with active oil cut-off n_AvgNew (Assume that the b corresponding to the n cylinder CynOff is 0) meets the following conditions:

[0263] In this example, C2 is set to 0.2, then Corresponding cylinder lower b CynOffFuelCut Equal to 0.

[0264] 5) In other cases, the sampling times Cnt CynOffDelay and self-learning correction coefficient k Adapt All remain unchanged. Corresponding to the cylinder b CynOffFuelCut Equal to 0.

[0265] b CynOffFuelCut A value of 1 indicates that the corresponding cylinder of the engine has experienced a real fuel cut-off.

[0266] The following supplementary explanation is about the update method of the preset value X and the preset range ±Y, as follows:

[0267] 1) Under the corresponding cylinder b CynOffFuelCut When it is 1, the preset value X under the corresponding cylinder and the Y in the preset range ±Y are updated accordingly. The update method is:

[0268] X=X(z)+0.02

[0269] Y=Y(z)+0.01

[0270] Where X(z) and Y(z) are the preset values ​​X and Y after the last update. The preset values ​​X and Y within the preset range ±Y for other cylinders are not updated.

[0271] 2) Under the corresponding cylinder b CynOffFuelCut When it is 0, the corresponding cylinder b will be accumulated CynOffFuelCut The number of times CNT is 0 (the default value of CNT is 0) is increased by 1 each time. It is only updated once when the active fuel cut-off condition is met.

[0272] Once CNT is not less than the preset value Z (8 in this example), the following will be done:

[0273] X=X(z)-0.007

[0274] Y=Y(z)-0.005

[0275] After the update is completed, CNT is cleared to 0 until the next active oil cut-off condition is met and the b value of the same cylinder is determined again. CynOffFuelCut Is it 0? If it is 0, add 1 to the number of times CNT under the corresponding cylinder again.

[0276] In other cases:

[0277] X=X(z)

[0278] Y=Y(z)

[0279] The reason why X and Y increase faster than they decrease is that X and Y only increase when a specific cylinder experiences continuous fuel outages, while they decrease when a specific cylinder does not. When a specific cylinder experiences continuous fuel outages, increasing X and Y is necessary to proactively verify that a fuel outage has occurred. Therefore, increasing the threshold for determining continuous fuel outages during subsequent judgment can expedite the process of determining a continuous fuel outage and, consequently, accelerate identification. However, when a specific cylinder experiences a continuous fuel outage, because this is an proactive verification and continuous fuel outages have not occurred, the threshold for determining a continuous fuel outage needs to be gradually reduced. This reduces the likelihood of a continuous fuel outage occurring in the cylinder. However, to avoid missing the identification of a continuous fuel outage, X and Y decrease more slowly.

[0280] The above completes the entire description of the first method for identifying combustion failure.

[0281] Figure 3 This is the second method for identifying engine combustion failure. As shown in Table 3, it is also mainly determined by the average engine speed and the average engine intake density, and is mainly verified by testing on the engine test bench through active forced fuel cut-off. The average engine speed and average intake density are the average values ​​of the current sampling cycle and the previous four times, a total of five sampling cycles, and are therefore updated in real time. The sampling cycle is 180° of crankshaft rotation, and each cylinder is from 80° of crankshaft angle after the compression top dead center of each cylinder to 260° after the compression top dead center of its corresponding cylinder. The test verification results of this example are shown in Table 3.

[0282] Table 3 Activation table of the second method for identifying engine combustion failure

[0283]

[0284]

[0285] When the above is equal to 0, it means that the method is not activated; when it is equal to 1 and the first 8 sampling periods are not 0, it means that the method is activated; in other cases, it means that the method is not activated.

[0286] The second method to identify engine combustion failure is Figure 3 Shown, including:

[0287] The first step is to read the running time of each tooth of the engine crankshaft flywheel after the above conditions are met. There are 58 teeth plus 2 missing teeth on the flywheel. The running time of each tooth refers to the time it takes for the engine flywheel to go from the current tooth to the next tooth when it is running. The time between the rising edge of the current tooth and the rising edge of the next tooth can be calculated. Note that because there are two missing teeth, the default running time of each tooth is 0, which will cause the running time of a total of 3 teeth (the first tooth before the missing tooth and the second missing teeth) to be 0. However, the tooth running time is an important parameter and will cause misjudgment of the engine combustion torque estimation result. Therefore, it is necessary to optimize the running time of the three teeth and take the running time of the tooth before these three teeth (that is, the second tooth before the missing tooth) and the running time of the first tooth after the second missing tooth as the average value.

[0288] It should be noted that if the falling edge is used, the running time of a total of 3 teeth (the first tooth after the missing tooth, and 2 missing teeth) will be 0.

[0289] The third step is to determine the evaluation window for estimating the engine combustion torque, that is, to determine the starting crankshaft angle and the tooth length Cnt for the engine combustion torque estimation. ToothArrayLen The selection method is to use the diagnostic evaluation window to judge the difference between normal and abnormal engine combustion torque to be the most obvious. The main approach is that the evaluation window includes the engine IMEP reaching the maximum value if the engine is burning normally. Specifically, in this example, the starting crankshaft angle phi Start The method for determining phi is: Start =f1(n,rho)+b CatHeat ×f2(n,rho), where b CatHeat =1, otherwise 0. Considering the catalyst ignition on the starting crankshaft angle phi Start The reason is that the engine ignition angle efficiency is too low during the catalyst ignition process, resulting in too little engine combustion torque. It is necessary to increase the evaluation window to assess whether the engine combustion is normal or not. f1(n,rho) and f2(n,rho) are determined by the engine speed and the density of the fresh air entering the cylinder respectively. The specific parameters are calibrated on the engine test bench. First, after the catalyst ignition is completed, f1(n,rho) and Cnt are calibrated. ToothArrayLen , and then calibrate f2(n,rho) and Cnt during the catalyst light-off processToothArrayLen2 The specific calibration method is determined based on the following: the evaluation window and the torque estimation method described later (determining normal and abnormal engine combustion torque) ensure that the difference between normal and abnormal engine combustion torque is most obvious. If it is not obvious, the calibration can be appropriately adjusted to see if the difference can be optimized. In this embodiment, if the absolute value of the average of the ratios of the difference between the normal and abnormal engine combustion torques divided by the normal combustion torque exceeds 20%, the difference between normal and abnormal engine combustion torques is considered to meet the requirement.

[0290] Starting crankshaft angle phi Start The running time of each tooth within the length of the first tooth to the subsequent contact teeth is represented by array t ToothTimes [0,1,2,...,Cnt ToothArrayLen +3], where array t ToothTimes [0,1,2,...,Cnt ToothArrayLen +3] is the running time of the first tooth, and the Cnt ToothArrayLen +3 is the Cnt ToothArrayLen +4 teeth running time. It should be noted here that the specific calculation of the running time of more than 4 teeth beyond the evaluation window is mainly for use in the subsequent combustion torque estimation filter algorithm.

[0291] The fourth step is to calculate the running time t of each tooth. ToothTimes [0,1,2,...,Cnt ToothArrayLen +3] to filter and output the filter running time t of each tooth ToothTimesFilter [0,1,2,...,Cnt ToothArrayLen +1].

[0292] The main consideration is that the design deviation of the flywheel teeth and the accuracy of the crankshaft position sensor will cause a lot of burr signals to appear during the operation time of each tooth. These burr signals need to be eliminated before estimating the engine combustion torque, thereby improving the accuracy of the combustion torque estimation. At the same time, after the filtering algorithm, only the operation time of the extra two teeth that exceed the evaluation window after filtering needs to be calculated. Among them, when the catalyst is not in the ignition state or the ignition state is completed, Cnt ToothArrayLen =Cnt ToothArrayLen1 ; In the catalyst ignition condition, Cnt ToothArrayLen =Cnt ToothArrayLen2 .

[0293] 1) Set the initial value t of the filter time for calculating the running time of each tooth ToothTimesFilterRaw [N] = r1 × t ToothTimes [N]+r2×t ToothTimes [N-1]+r3×t ToothTimes[N-2]; where N is the array t in ToothTimes [0,1,2,...,Cnt ToothArrayLen +3] in the Nth sequence number. In particular, when N = 0 or 1, t ToothTimesFilterRaw [0] = t ToothTimes [0], t ToothTimesFilterRaw [1] = t ToothTimes [0].

[0294] Where r1, r2, and r3 add up to 1. This determination method, along with the torque estimation method described later (determining normal and abnormal engine combustion torque), maximizes the difference between normal and abnormal engine combustion torque. If it is not obvious, the calibration can be appropriately adjusted to see if the difference can be optimized. In this embodiment, if the absolute value of the average of the ratios of the difference between the normal and abnormal engine combustion torques divided by the normal combustion torque exceeds 20%, the difference between normal and abnormal engine combustion torques is considered to meet the requirement. In this example, the values ​​are 0.1708, 0.8821, and -0.0529, respectively.

[0295] 2) Based on this, N=0,1,2,…, Cnt ToothArrayLen +3 initial filter time, and the final filter running time t ToothTimesFilter [N] = t ToothTimesFilterRaw [N+2], after forming the array, becomes t ToothTimesFilter [0,1,2,...,Cnt ToothArrayLen +1].

[0296] In the fifth step, the engine speed is estimated based on the filtered running time of each tooth.

[0297] in, In this example, C1 is set to 0.000001min / (r*us).

[0298] Based on this, the engine speed array n of each tooth operation process is formed EstRpm [0,1,2,...,Cnt ToothArrayLen +1].

[0299] The sixth step is to estimate the initial value M of the torque difference of each tooth based on the engine speed during the operation of each tooth. EstTrqErrRaw [0,1,2,...,Cnt ToothArrayLen +1], the engine torque difference refers to the difference in engine torque change from the start of the current tooth operation to the end of the next tooth operation. If it is a negative value, the engine torque is increasing, and if it is a positive value, the engine torque is decreasing.

[0300] Among them, M EstTrqErrRaw [N]=C2×[(nEstRpm [N]) 2 -(n EstRpm [N-1]) 2 ], where C2 in this example is 3000Nm / (rpm) 2 .

[0301] Step 7: Initial value M of torque difference of each tooth EstTrqErrRaw [0,1,2,...,Cnt ToothArrayLen +1] to filter and output the filtered torque difference M of each tooth EstTrqErr [0,1,2,...,Cnt ToothArrayLen -1]. The main purpose is to remove the torque signal burrs, thereby improving the accuracy of combustion torque estimation.

[0302] 1) Filter initial value M of the initial value of the torque difference of each tooth EstTrqErrFilter [N] = r1 × M EstTrqErrRaw [N]+r2×M EstTrqErrRaw [N-1]+r2×M EstTrqErrRaw [N-2]. In particular, when N=0 or 1, M EstTrqErrFilter [0] = M EstTrqErrRaw [0],M EstTrqErrFilter [1]=M EstTrqErrRaw [0].

[0303] 2) Based on this, N=0,1,2,…, Cnt ToothArrayLen +3 is the initial value of the filtered torque difference of each tooth, and the final filtered torque difference M EstTrqErr [N]=M EstTrqErrFilter [N+2], after forming the array, becomes M EstTrqErr [0,1,2,...,Cnt ToothArrayLen -1].

[0304] The eighth step is to calculate the total torque variation M within the evaluation window used to estimate the engine combustion torque. TrqDetectDelta , mainly to M EstTrqErr [0,1,2,...,Cnt ToothArrayLen -1] are added. When adding, special attention should be paid to adding the non-negative and negative numbers separately first and then adding the two sums to obtain the final total torque change M. TrqDetectDelta The purpose of this is to ensure the accuracy of the accumulation algorithm. If integers and negative numbers are added, some data precision will be lost during the code operation, resulting in a loss of precision in the calculation results.

[0305] Step 9: Determine whether the engine combustion torque is abnormal.

[0306] 1) Total torque change M TrqDetectDelta Filter to obtain the total torque change M after filtering TrqSumMeanNew :M TrqSumMeanNew =(1-r TrqWeightMean )×M TrqSumMean (z)+r TrqWeightMean ×M TrqDetectDelta ; where M TrqSumMean (z) is the total torque change after filtering in the previous sampling period (especially, its initial default value is 0), and its sampling update period is 180 degrees crankshaft angle, that is, from the starting crankshaft angle phi Start At the beginning, the sampling calculation is performed again after the crankshaft rotates 180 degrees. Among them, the total torque change filter coefficient r TrqWeightMean In this example, the value is 0.05 when the catalyst is activated and 0.1 when the catalyst is not activated.

[0307] 2) Calculate the initial value S of the torque characteristic value used to evaluate whether the combustion torque is abnormal TrqDetectRaw :

[0308] S TrqDetectRaw =(1-r TrqWeightVar )×S TrqDetectRaw (z)+r TrqWeightVar ×(M TrqDetectDelta -M TrqSumMeanNew ) 2

[0309] Among them S TrqDetectRaw (z) is the initial value of the torque characteristic value of the previous sampling period (especially, its first default value is 0), and its sampling update period is defined in the same way as the sampling period described above. TrqWeightVar :

[0310] r TrqWeightVar =(1-k TrqWeightVar )×r TrqWeightVar (z)+k TrqWeightVar ×(r TrqWeightGain ×b TrqDetectErr (z)+r TrqWeightInc )

[0311] Among them, r TrqWeightVar (z) is the initial value filter coefficient of the torque characteristic value in the previous sampling period. Its sampling update period is defined in the same way as the sampling period described above. Its initial default value is 0.15. The update coefficient k TrqWeightVar In this example, the gain coefficient is 0.65 when the catalyst is activated and 0.7 when the catalyst is not activated. TrqWeightGain In this example, the catalyst is activated when it is ignited and the catalyst is not activated when it is ignited. The cumulative coefficient rTrqWeightInc In this example, the value is 0.17 when the catalyst is activated and 0.1 when the catalyst is not activated. TrqDetectErr (z) is the flag indicating whether the engine combustion torque is abnormal in the previous sampling period. If it is abnormal, it is set to 1; if it is not abnormal, it is set to 0.

[0312] 3) Initial value of torque characteristic value S TrqDetectRaw Filter and obtain the filtered torque characteristic value S TrqDetect :

[0313] S TrqDetect =(1-r TrqWeightVarFilt )×S TrqDetect (z)+r TrqWeightVar ×S TrqDetectRaw

[0314] Among them, S TrqDetect (z) is the total torque change after filtering in the previous sampling period (especially, its initial default value is 0), and its sampling update period is defined in the same way as the sampling period described above. TrqWeightVarFilt In this example, the value is 0.3 when the catalyst is activated and 0.15 when the catalyst is not activated.

[0315] 4) Determine the lower limit value M for determining the abnormal combustion torque TrqBoundLower :

[0316]

[0317] where k BunndLower is the lower limit deviation coefficient, k BunndLower In this example, the value is 1.8 when the catalyst is activated and 2.3 when the catalyst is not activated.

[0318] 5) Calculate the torque deviation M used to determine whether the engine combustion torque is abnormal ErrEst :

[0319] M ErrEst =M TrqDetectDelta -M TrqBoundLower

[0320] 6) Determine whether the engine combustion torque is normal.

[0321] If it appears, M ErrEst <M ErrThresh , combustion torque deviation limit M ErrThresh In this example, the speed is -0.8 Nm when the catalyst is activated and -1.2 Nm when the catalyst is not activated. TrqDetectErr Set to 1, the engine combustion torque is abnormal; otherwise b TrqDetectErrIf it is 0, there is no abnormality in the engine combustion torque;

[0322] 7) Determine which cylinder of the engine has failed to burn.

[0323] If b TrqDetectErr If set to 1, it will read which cylinder is in the power stroke under the corresponding average window, indicating that the corresponding cylinder has combustion failure.

[0324] The above completes the entire description of the second method for identifying combustion failure.

[0325] Finally, in the above two combustion failure identification methods, if the following situations occur:

[0326] (1) If the cylinder number of the combustion failure detected by the first method is the same as the cylinder number of the combustion failure detected by the second method, the combustion failure of the corresponding cylinder will be output; and the combustion failure fault judgment of the corresponding cylinder will not be performed in the subsequent vehicle driving cycle until the diagnostic instrument clears the fault.

[0327] (2) If the first method detects a cylinder number with combustion failure, but the second method does not detect combustion failure on the same cylinder number, and the number of driving cycles that occur exceeds the preset number A (2 in this example), it is characterized as a combustion failure, and the M under the cylinder number with combustion failure detected by the second method is set to ErrThresh The value is updated to C times the last update (1.05 in this example). This value is saved after the vehicle is powered off. The next time a combustion failure occurs, the updated value will be used for evaluation. Furthermore, combustion failure diagnosis for the corresponding cylinder will not be performed in subsequent vehicle driving cycles until the diagnostic instrument clears the fault.

[0328] (3) If the first method detects a cylinder number with combustion failure, but the second method does not detect combustion failure on the same cylinder number, and the number of driving cycles that have occurred does not exceed the preset number A, then the combustion failure is in a pending state (the pending state means that the combustion failure has occurred but is not confirmed). The r under the cylinder number detected by the first method for combustion failure is CynDetectOffLim The update is E times the last update (0.992 in this example), and is updated at most once per driving cycle. The corresponding cylinder combustion failure fault is still determined in subsequent vehicle driving cycles.

[0329] (4) If the second method detects a cylinder number with combustion failure, but the first method does not detect combustion failure on the same cylinder number, and the number of driving cycles that occur exceeds the preset number B (B is not less than A, because the first scheme uses active strong control to identify whether combustion failure occurs and conducts multiple active verifications again, and its verification cycle is longer. Therefore, the number of confirmations A for the first method to detect combustion failure is relatively small, but the second method requires more times to confirm, and in this example, 5 is taken), then it indicates combustion failure, and the r under the cylinder number detected by the first method for combustion failure is set to CynDetectOffLim The threshold is updated to D times the value of the last update (D is greater than 1 but not greater than C. This is because the first solution uses active sampling and strong control to identify combustion failure, performing multiple active verifications. The threshold is updated more cautiously, using 1.02 in this example). These thresholds are saved after the vehicle is powered off. The next time a combustion failure occurs, the updated threshold will be used for evaluation. Furthermore, combustion failure fault determination for the corresponding cylinder will not be performed in subsequent vehicle driving cycles until the diagnostic instrument clears the fault.

[0330] (5) If the second method detects a cylinder number with combustion failure, but the first method does not detect combustion failure for the same cylinder number, and the number of driving cycles that occur does not exceed the preset number B, then the combustion failure is marked as pending (pending means that the combustion failure has occurred but is not confirmed). At the same time, the M under the cylinder number detected by the second method for combustion failure is ErrThresh The threshold is updated to F times the value of the last update (F is not greater than E because the first solution uses active strong control sampling to identify whether combustion failure has occurred and performs multiple active verifications. The threshold is updated more cautiously and is set to 0.989 in this example). The threshold is updated at most once per driving cycle and combustion failure fault judgment of the corresponding cylinder is still performed in subsequent vehicle driving cycles.

[0331] (6) If neither the first nor the second method currently detects a combustion failure in the same cylinder, the combustion failure is marked as pending (a pending state means that the combustion failure has occurred but is not confirmed). The corresponding cylinder combustion failure fault determination is still performed in subsequent vehicle driving cycles.

[0332] The above completes the description of the method for multi-dimensionally identifying engine combustion failure.

[0333] An embodiment of the present invention further provides an electronic device, Figure 4This is a schematic diagram of the structure of an electronic device provided by an embodiment of the present invention, such as a smart phone, tablet computer, laptop computer, desktop computer, rack server, blade server, tower server or cabinet server (including an independent server or a server cluster composed of multiple servers), etc. The computer electronic device 20 of this embodiment includes at least but not limited to: a memory 21 and a processor 22 that can be interconnected through a system bus, such as Figure 4 It should be pointed out that Figure 4 The electronic device 20 is shown only with components 21 - 22 , but it is understood that implementing all of the illustrated components is not a requirement, and greater or fewer components may alternatively be implemented.

[0334] In this embodiment, the memory 21 (i.e., a readable storage medium) includes a flash memory, a hard disk, a multimedia card, a card-type memory (e.g., SD or DX memory), a random access memory (RAM), a static random access memory (SRAM), a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), or a programmable read-only memory (PROM). The memory 21 may also be an external storage device of the electronic device 20, such as a plug-in hard disk, a smart memory card (SMC), a secure digital (SD) card, a flash memory card, etc. equipped on the electronic device 20. Of course, the memory 21 may also include both an internal storage unit of the electronic device 20 and an external storage device thereof. In this embodiment, the memory 21 is generally used to store the operating system and various application software installed on the electronic device 20, such as the program code of the method for multi-dimensionally identifying engine combustion failure in the method embodiment. In addition, the memory 21 may also be used to temporarily store various data that has been output or is about to be output.

[0335] In some embodiments, the processor 22 can be a central processing unit (CPU), a controller, a microcontroller, a microprocessor, or other data processing chip. The processor 22 is generally used to control the overall operation of the electronic device 20. In this embodiment, the processor 22 is used to execute program code stored in the memory 21 or process data. For example, the processor 22 executes a device storing program code for a method for multi-dimensionally identifying engine combustion failure, thereby implementing the method for multi-dimensionally identifying engine combustion failure in the method embodiment.

[0336] The present invention also provides a computer-readable storage medium, such as a flash memory, a hard disk, a multimedia card, a card-type memory (e.g., SD or DX memory), a random access memory (RAM), a static random access memory (SRAM), a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), a programmable read-only memory (PROM), a magnetic storage device, a disk, an optical disk, a server, an App store, etc., on which a computer program is stored. When the program is executed by a processor, the corresponding function is implemented. The computer-readable storage medium of this embodiment is used to store program code for a method for multi-dimensionally identifying engine combustion failure. When executed by a processor, the method for multi-dimensionally identifying engine combustion failure of the method embodiment is implemented.

[0337] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0338] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0339] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0340] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0341] In summary, the present invention provides a method, electronic device and storage medium for multi-dimensional identification of engine combustion failure, which selects different methods under different working conditions to perform engine combustion failure torque reduction judgment, that is, the cylinder number detected by the first multi-dimensional method for identifying engine combustion failure and the cylinder number detected by the second multi-dimensional method for identifying engine combustion failure are jointly determined to determine the cylinder number of the engine combustion failure, and if the judgment results are different, the judgment threshold is continuously updated, thereby improving the accuracy of engine combustion failure torque reduction judgment, thereby reminding the driver to perform timely maintenance and inspection, and also protecting the engine in time.

[0342] It should be noted that the size of the serial numbers of the steps in the above 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 this application.

[0343] It should be pointed out that, according to the needs of implementation, the various steps / components described in this application can be split into more steps / components, or two or more steps / components or partial operations of steps / components can be combined into new steps / components to achieve the purpose of the present invention.

[0344] It will be easily understood by those skilled in the art that the above are merely preferred embodiments of the present invention and are 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 scope of protection of the present invention.

Claims

1. A multi-dimensional method for identifying engine combustion failure, characterized in that: The method includes: When the engine combustion failure judgment enabling conditions are met, the engine combustion failure judgment is performed: When the activation condition of the first method for identifying engine combustion failure is met, detecting the cylinder number of the combustion failure by the first method for identifying engine combustion failure; When the activation condition of the second method for identifying engine combustion failure is met, detecting the cylinder number of the combustion failure by the second method for identifying engine combustion failure; The cylinder number detected by the first method for identifying engine combustion failure and the cylinder number detected by the second method for identifying engine combustion failure are used together to determine the cylinder number of the engine combustion failure; Among them, the first method of identifying engine combustion failure includes: Determine the value of an initial flag indicating whether combustion of a fixed cylinder has failed based on the maximum and minimum values ​​of the final running time average value; determining a value of a flag indicating whether combustion of a fixed cylinder has failed according to the value of the initial flag indicating whether combustion of the fixed cylinder has failed; Determining the value of the final flag bit indicating whether the fixed cylinder has failed to burn according to the value of the flag bit indicating whether the fixed cylinder has failed to burn, and finally obtaining the cylinder number of the failed cylinder; The second method of identifying engine combustion failure includes: Calculating a total torque variation in an evaluation window of the engine combustion torque based on the filtered torque difference array of each tooth; The cylinder number of the combustion failure is determined according to the total torque change.

2. The multi-dimensional identification method for engine combustion failure according to claim 1, characterized in that: Engine combustion failure judgment enabling conditions include: (1) Entering the fire diagnosis area specified in the regulations; (2) No request for fuel cut-off; (3) The gear position has not changed, and the first time after the gear position changes is delayed; (4) The clutch is in full engagement and the second time is delayed after the clutch is fully engaged; (5) Non-uneven road surface; (6) The water temperature is within the preset range; (7) The throttle opening fluctuates within a certain range; (8) The engine is in running state; When all of the above conditions are met, the engine combustion failure judgment enabling condition is met.

3. The multi-dimensional identification method for engine combustion failure according to claim 1, characterized in that: The activation condition of the first method for identifying engine combustion failure is determined by the average engine speed and the average engine intake air density; wherein the average engine speed and the average engine intake air density are respectively the average of the engine speed and the engine intake air density in the current sampling period and the previous sampling periods; If the activation condition of the first method for identifying engine combustion failure in the current sampling period is not satisfied, the first method for identifying engine combustion failure is not activated; If the activation conditions of the first method for identifying engine combustion failure in the current sampling period are met, and the activation conditions of the first method for identifying engine combustion failure in the previous sampling periods are all met, then the first method for identifying engine combustion failure is activated; In other cases, the first method of identifying engine combustion failure is not activated; The activation conditions of the second method for identifying engine combustion failure are similar.

4. The multi-dimensional identification method for engine combustion failure according to claim 1, characterized in that: The first method for identifying engine combustion failure also includes: Obtain the operating time of each cylinder of the engine at a specific crankshaft operating angle, and calculate the average operating time of each cylinder of the engine over several consecutive sampling periods; Divide the evaluation area according to the engine speed and determine the evaluation time update coefficient of each cylinder of the engine in each evaluation area; Determining whether activation conditions for engine combustion failure identification evaluation time update optimization processing are met; if not, maintaining the evaluation time update coefficients of each cylinder of the engine in each evaluation area unchanged; if so, determining the value of the evaluation time update optimization counter, and determining an initial value of the evaluation time update coefficient based on the evaluation time update coefficient and the average value of the operating time; Determine the value of the flag bit according to the value of the evaluation time update optimization counter, and 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; Determine a final running time according to the value of the flag bit, the updated evaluation time update coefficient, and the running time; An average value of the final operating time of each cylinder of the engine in a plurality of consecutive sampling periods is calculated according to the final operating time, and a maximum value and a minimum value of the average value of the final operating time are determined.

5. The multi-dimensional identification method for engine combustion failure according to claim 4, characterized in that: The specific crankshaft operating angle section is the crankshaft angle from 80° after the compression top dead center of each cylinder of the engine to 260° after the compression top dead center of its corresponding cylinder; The activation conditions for the updated optimization processing of the engine combustion failure identification evaluation time include: (1) The engine is in running state; (2) The engine did not experience combustion failure at this time; (3) All cylinders of the engine are in the fuel cut-off state; (4) The engine does not directly participate in driving the vehicle; (5) The engine does not experience knock or pre-ignition; (6) The running time of each cylinder of the engine is not zero in several consecutive sampling periods; (7) The engine has no malfunction; When all the above conditions are met, the activation conditions for the engine combustion failure identification evaluation time update optimization process are met.

6. The multi-dimensional identification method for engine combustion failure according to claim 4, characterized in that: Determining a value of an evaluation time update optimization counter, and determining an initial value of an evaluation time update coefficient according to the evaluation time update coefficient and the running time average value, comprising: If any of the following conditions is met, the value of the evaluation time update optimization counter is reset to 1, and the initial value of the evaluation time update coefficient of each cylinder of the engine is reset to the evaluation time update coefficient within the current evaluation area: (1) The activation conditions for the engine combustion failure identification evaluation time update optimization process are not met; (2) The current evaluation area changes; If both of the above conditions are not met, the value of the evaluation time update optimization counter is increased by 1 after each sampling period, and the initial value of the evaluation time update coefficient is accumulated at the same time. The accumulation method is as follows: For each cylinder of the engine, calculate the quotient of its running time average value and the average of the running time average values ​​of all cylinders of the engine in each sampling period, add the initial value of the evaluation time update coefficient accumulated in the previous sampling period to the reciprocal of the quotient to obtain the initial value of the evaluation time update coefficient accumulated in the current sampling period; Determining a flag value according to a value of an evaluation time update optimization counter, and determining an updated evaluation time update coefficient according to the flag value, the evaluation time update coefficient initial value, and the evaluation time update coefficient, including: If the evaluation time of the current evaluation area is updated, the value of the optimization counter is not less than the preset value. Number of times Greater than the preset number of times , then the flag value is 1; otherwise the flag value is 0; where, the number of times The accumulation method is: after the value of the optimization counter of the evaluation time of the current evaluation area is reset, it is accumulated again. If the value of the optimization counter of the evaluation time of the current evaluation area is not less than the preset value, , then the number of times Add 1; every time the evaluation time of the current evaluation area is updated and the optimization counter is reset, the number of times Accumulate at most once; When the flag value is 0 and the value of the evaluation time update optimization counter of the current evaluation area is not less than the preset value , updating the evaluation time update coefficient by calculating, for a cylinder in the current evaluation area, the product of the initial value of the evaluation time update coefficient and the first weighting coefficient, and simultaneously calculating the difference between 1 and the first weighting coefficient and the product of the difference and the evaluation time update coefficient corresponding to the cylinder in the current evaluation area; the sum of the two products is the updated evaluation time update coefficient; When the flag value is 1 and the value of the evaluation time update optimization counter of the current evaluation area is not less than the preset value , updating the evaluation time update coefficient by calculating, for a cylinder in the current evaluation area, the product of the initial value of the evaluation time update coefficient and the second weighting coefficient, and simultaneously calculating the difference between 1 and the second weighting coefficient and the product of the difference and the evaluation time update coefficient corresponding to the cylinder in the current evaluation area, the sum of the two products being the updated evaluation time update coefficient; wherein both the first weighting coefficient and the second weighting coefficient are less than 1, and the second weighting coefficient is not greater than the first weighting coefficient; Determining a final running time according to the value of the flag bit, the updated evaluation time update coefficient, and the running time includes: When the flag value is 0, the running time of each cylinder of the engine is the final running time; When the value of the flag bit is 1, the product of the running time of each cylinder of the engine and the corresponding updated evaluation time update coefficient is the final running time.

7. The multi-dimensional identification method for engine combustion failure according to claim 4, characterized in that: Determining a value of an initial flag indicating whether combustion of a fixed cylinder has failed according to a maximum value and a minimum value of the final running time average value includes: Determining a characteristic coefficient according to the maximum and minimum values ​​of the final running time average values ​​includes: Get the maximum value of the final running time average value in the current sampling period With minimum value , and calculate the corresponding intermediate value ; Similarly, calculate the intermediate values ​​corresponding to several sampling periods before the current sampling period, and finally calculate the average value of all intermediate values, which is the characteristic coefficient; Determining the value of an initial flag indicating whether the fixed cylinder has failed combustion based on the characteristic coefficient and a preset threshold coefficient for determining whether the fixed cylinder has failed combustion includes: If 1 plus If the characteristic coefficient of the fixed cylinder is greater than or equal to the preset threshold coefficient for judging whether the fixed cylinder combustion fails, the value of the initial flag bit of whether the fixed cylinder combustion fails is 1, otherwise it is 0; in, is a self-learning correction coefficient. The threshold coefficient used to determine combustion failure in a fixed cylinder is determined by the average engine speed and the average engine intake air density. The average engine speed and the average engine intake air density are the average values ​​of the engine speed and the engine intake air density in the current sampling period and the previous sampling periods, respectively. Determining the value of the flag bit indicating whether combustion of the fixed cylinder has failed according to the value of the initial flag bit indicating whether combustion of the fixed cylinder has failed includes: On the premise that the value of the initial flag bit of the fixed cylinder combustion failure is 1, if: Case 1: Determine the cylinder number whose final running time average is equal to the maximum value; Case 2: If a cylinder meets the following conditions, its cylinder number is determined: first, the difference between the maximum value and the average value of the final operating time of the cylinder is calculated, and then the quotient of the difference and the maximum value is calculated. The quotient is greater than zero and less than the preset value X; Case 3: The cylinder meeting Case 1 or Case 2 meets the following conditions: First, all running times and all final running times of the cylinder meeting Case 1 or Case 2 within a number of consecutive sampling periods are calculated, and the differences between them and the maximum value are then calculated. The quotient of these differences and the maximum value is within a preset range of -Y to Y, where Y is a preset value. The fourth case: at least one cylinder does not meet the first or the second case; Case 5: The following situation exists: When the cylinder numbers that meet the first or second conditions are recorded according to the cylinder working order, the number of cylinders that do not meet the first or second conditions between two consecutive cylinder numbers that meet the first or second conditions is not less than 2, and the cylinder number equal to the minimum value is not the next working cylinder number after the cylinder number that meets the first or second conditions; If the first case, the second case, the third case, the fourth case, and the fifth case are repeated multiple times If both of the above conditions are met, it indicates that the cylinder that meets the first condition or the second condition has combustion failure, and the flag of whether the corresponding cylinder combustion fails or not is set to Set to 1, otherwise 0; Determining the value of the final flag bit of whether the fixed cylinder combustion fails according to the value of the flag bit of whether the fixed cylinder combustion fails, and finally obtaining the cylinder number of the combustion failure, including: Actively cut off fuel for cylinders that meet the first or second conditions, and re-obtain the final average running time of each cylinder of the engine in the fuel cut-off state T nˍAvgNew The maximum value of the average final running time of each cylinder of the engine in the fuel cut-off state T maxNew With minimum value T minNew ; (1) For the flag bit b CynOff The value of the cylinder is 1, if , ,and When the fixed cylinder combustion failure of this cylinder is the final flag position, that is, the fuel cut flag position b CynOffFuelCut = b CynOff =1, and the number of multiple samplings Cnt CynoffDelay Subtract 1 and save after power off, the self-learning correction coefficient k Adapt Remain unchanged; is the average final running time of the nth cylinder of the engine, C 1 is the default value; (2) For the flag bit b CynOff The value of the cylinder is 1, if , ,and If only one of the following is met, the oil cut-off flag of this cylinder will be b CynOffFuelCut =0, the number of multiple sampling times Cnt CynoffDelay Remain unchanged; the self-learning correction coefficient , and save after power off; (3) For the flag bit b CynOff The value of the cylinder is 1, if , ,and If all of the above are not satisfied, the oil cut-off mark of this cylinder will be b CynOffFuelCut =0, the multiple sampling times Cnt CynoffDelay Add 2, the self-learning correction coefficient , and save after power off; (4) For the flag bit b CynOff The cylinder with a value of 0, if the average final running time of the cylinder satisfy , then the oil cut-off flag of this cylinder b CynOffFuelCut =0, the number of multiple sampling times Cnt CynoffDelay Remain unchanged, the self-learning correction coefficient , and save it after power off; C 2 is the default value; (5) In other cases, the oil cut-off mark of the cylinder b CynOffFuelCut =0, the number of multiple sampling times Cnt CynoffDelay and the self-learning correction coefficient k Adapt remain unchanged; If the value of the initial flag is 1, the fuel cut flag of the engine cylinder b CynOffFuelCut =1, it means that the cylinder of the engine has a real fuel cut-off, that is, combustion failure.

8. The multi-dimensional identification method for engine combustion failure according to claim 7, characterized in that: The update method of the preset values ​​​​X and Y is: 1) At the oil cut-off mark of the cylinder When it is 1, the preset values ​​X and Y under the corresponding cylinder are updated accordingly. The update method is: X=X(z)+0.02 Y=Y(z)+0.01 Where X(z) and Y(z) are the preset values ​​X and Y after the last update; the preset values ​​X and Y for other cylinders are not updated; 2) At the oil cut-off mark of the cylinder When it is 0, the corresponding cylinder The number of times CNT is 0 is increased by 1 each time. It is updated only once when the active fuel cut-off condition is met. Once CNT is not less than the preset value Z, the following will be done: X=X(z)-0.007 Y=Y(z)-0.005 After the update is completed, CNT is cleared to 0 until the next active oil cut-off condition is met and the oil cut-off flag of the same cylinder is judged again. Is it 0? If it is 0, then increase the number of times CNT under the corresponding cylinder by 1 again; In other cases: X=X(z) Y=Y(z); Active fuel cut-off conditions include: 1) The engine combustion failure judgment enabling conditions are met; 2) The vehicle speed exceeds the preset value; 3) The engine does not experience knock and pre-ignition; 4) The exhaust temperature does not exceed the preset protection temperature; 5) GPF does not request active regeneration; 6) The oxygen storage capacity of the catalyst does not exceed the preset coefficient of its total oxygen storage capacity; 7) No failure of fuel injection system related components occurs; 8) The difference between the current average engine speed and the average engine speed obtained when determining the threshold coefficient for determining combustion failure in a fixed cylinder is within a preset range; 9) The difference between the current average engine intake air density and the average engine intake air density obtained when determining the threshold coefficient for determining combustion failure of a fixed cylinder is within a preset range; When all the above conditions are met, the active fuel cut-off condition is met; and only when the active fuel cut-off condition is met, the active fuel cut-off is performed on the cylinder that meets the first condition or the second condition.

9. The multi-dimensional identification method for engine combustion failure according to claim 7, characterized in that: The second method of identifying engine combustion failure includes: Get the running time of each tooth of the engine crankshaft flywheel; determining a starting crankshaft angle and tooth length for estimating engine combustion torque, determining an evaluation window for estimating engine combustion torque based on the starting crankshaft angle and tooth length, and obtaining an array of operating times of each tooth within the evaluation window in combination with the operating times of each tooth; Filter the running time array of each tooth and output the filtered running time array of each tooth; Estimating the engine speed based on the filter running time array of each tooth to obtain an engine speed array; estimating the initial torque difference value of each tooth based on the engine speed during the operation of each tooth, and obtaining an array of initial torque difference values; The initial value array of the torque difference of each tooth is filtered, and the filtered torque difference array of each tooth is output.

10. The multi-dimensional identification method for engine combustion failure according to claim 9, characterized in that: Get the running time of each tooth of the engine crankshaft flywheel, including: The running time of each tooth refers to the time it takes for the engine flywheel to go from the current tooth to the next tooth when the engine is running; for a missing tooth, the average running time of the teeth before and after the missing tooth is taken as the running time of the missing tooth; Determining a starting crankshaft angle and tooth length for estimating engine combustion torque, determining an evaluation window for estimating engine combustion torque based on the starting crankshaft angle and tooth length, and obtaining an array of operating times of each tooth within the evaluation window in combination with the operating time of each tooth, including: Starting crankshaft angle The method to determine is: ;in, The catalyst light-off control is activated. is 1, otherwise 0; and is the calibration value, which is determined by the engine speed n and the density of fresh air entering the cylinder rho Joint decision: After the catalyst is ignited, the calibration value is determined and the length of the first tooth , calibrate the calibration value during the catalyst light-off process and the second tooth length ,The calibration is determined based on: the difference between the combustion torque when the engine fails to burn and the combustion torque when there is no combustion failure within the evaluation window meets the preset requirements; An evaluation window for estimating the engine combustion torque is determined based on the starting crankshaft angle and the tooth length, and the evaluation window and the running time array of the four consecutive teeth after the evaluation window are obtained in combination with the running time of each tooth. ; Among them, when the catalyst is not in the ignition state or the ignition state is completed, the number of teeth is ; When the catalyst is ignited, the number of teeth and length ; Filter the running time array of each tooth and output the filtered running time array of each tooth, including: Calculate the initial value of the filter time for the running time of each tooth : Where N is the running time array When N=0 or 1, , ; 、 and is a weighting coefficient, the sum of the three is 1, and the determination method is: the difference between the combustion torque when the engine combustion fails and the combustion torque when there is no combustion failure in the evaluation window meets the preset requirements; Determine the filter run time for each tooth , get the filter running time array of each tooth ; The engine speed is estimated based on the filter running time array of each tooth to obtain the engine speed array, including: Calculating engine speed ; Where C1 is the coefficient; Get the engine speed array ; The initial torque difference value of each tooth is estimated based on the engine speed during the operation of each tooth, and an array of initial torque difference values ​​is obtained, including: Calculate the initial value of the torque difference of each tooth ; Where C2 is the coefficient; Get the initial value array of torque difference ; Filter the initial value array of the torque difference of each tooth and output the filtered torque difference array of each tooth, including: Similar to the running time array filtering, the filtered torque difference array is obtained .

11. The method for multi-dimensionally identifying engine combustion failure according to claim 10, characterized in that: Calculating the total torque variation within the evaluation window based on the filtered torque difference array of each tooth includes: The filtered torque difference array Add up the numbers in to get the total torque change ; Determining the cylinder number of the combustion failure according to the total torque change includes: Change in total torque Filter to get the total torque change after filtering : Where, is the total torque change after filtering in the previous sampling period; is the total torque variation filter coefficient; Calculate the initial value of the torque characteristic value used to evaluate whether the combustion torque is abnormal : in, is the initial value of the torque characteristic value of the previous sampling period; is the initial value filter coefficient of the torque characteristic value, and the calculation method is: in, is the initial value filter coefficient of the torque characteristic value of the previous sampling period; is the update coefficient; is the gain coefficient; is the cumulative coefficient; The flag indicating whether the engine combustion torque is abnormal in the previous sampling period is 1 if it is abnormal, and 0 if it is not abnormal. Initial value of torque characteristic value Filter to obtain the filtered torque characteristic value : in, is the total torque change after filtering in the previous sampling period; is the filtering coefficient of the torque characteristic value after filtering; Determine the lower limit value for determining combustion torque abnormality : in, is the coefficient of deviation of the lower limit; Calculates torque deviation to determine if engine combustion torque is abnormal : Determine whether the engine combustion torque is normal: If it appears ,but Set to 1, the engine combustion torque is abnormal; otherwise is 0, and the engine combustion torque is normal; is the combustion torque deviation limit; Determine the cylinder number where combustion failed: if If set to 1, the cylinder number in the power stroke under the corresponding evaluation window is read, indicating that the corresponding cylinder has combustion failure.

12. The multi-dimensional identification method for engine combustion failure according to claim 10, characterized in that: The difference between the combustion torque when the engine fails to burn and the combustion torque when there is no combustion failure within the evaluation window meets the preset requirements, including: The difference between the combustion torque when the combustion failure occurs and the combustion torque when there is no combustion failure is divided by the combustion torque when there is no combustion failure to obtain a ratio; If the absolute value of the average value of the ratio exceeds the preset ratio threshold, the preset requirement is met.

13. The multi-dimensional identification method for engine combustion failure according to claim 11, characterized in that: The cylinder number detected by the first method for identifying engine combustion failure and the cylinder number detected by the second method for identifying engine combustion failure are used together to determine the cylinder number of the engine combustion failure, including: If the cylinder number detected by the first method for identifying engine combustion failure is the same as the cylinder number detected by the second method for identifying engine combustion failure, combustion failure occurs in the corresponding cylinder; and combustion failure fault judgment for the corresponding cylinder will not be performed in subsequent vehicle driving cycles until the diagnostic instrument clears the fault. If the first method for identifying engine combustion failure detects the cylinder number of combustion failure, but the second method for identifying engine combustion failure does not detect the same cylinder number of combustion failure, and the number of driving cycles that occur exceeds the preset number A, it indicates that the combustion has failed, and the combustion torque deviation limit of the corresponding cylinder under the second method for identifying engine combustion failure is set to Updated to the first multiple; and in subsequent vehicle driving cycles, the corresponding cylinder combustion failure fault judgment will not be performed until the diagnostic instrument clears the fault and then the combustion failure fault judgment will be performed again; If the first method for identifying engine combustion failure detects a cylinder number with combustion failure, but the second method for identifying engine combustion failure does not detect combustion failure in the same cylinder number, and the number of driving cycles in which the combustion failure occurs does not exceed the preset number A, then the combustion failure is indicated as being in a pending state, and the threshold coefficient for determining fixed cylinder combustion failure for the corresponding cylinder under the first method for identifying engine combustion failure is updated to the second multiple, and is updated at most once per driving cycle, and combustion failure fault determination for the corresponding cylinder is still performed in subsequent vehicle driving cycles; If the second method for identifying an engine combustion failure detects a cylinder number with combustion failure, but the first method for identifying an engine combustion failure does not detect combustion failure in the same cylinder number, and the number of driving cycles in which combustion failure occurs exceeds a preset number B, then combustion failure is indicated, and the threshold coefficient for determining fixed cylinder combustion failure for the corresponding cylinder under the first method for identifying an engine combustion failure is updated to a third multiple, and combustion failure fault determination for the corresponding cylinder is not performed in subsequent vehicle driving cycles until the diagnostic instrument clears the fault, at which time combustion failure fault determination is performed again; If the second method for identifying engine combustion failure detects the cylinder number of combustion failure, but the first method for identifying engine combustion failure does not detect combustion failure on the same cylinder number, and the number of driving cycles that occur does not exceed the preset number B, then the combustion failure is indicated as pending, and the combustion torque deviation limit of the corresponding cylinder under the second method for identifying engine combustion failure is set to The update is a multiple of four and is updated at most once per driving cycle, and the corresponding cylinder combustion failure fault judgment is still performed in subsequent vehicle driving cycles; If the first method for identifying engine combustion failure and the second method for identifying engine combustion failure do not detect the same cylinder number, combustion failure fault judgment is still performed in the subsequent vehicle driving cycle; Among them, the preset number B is greater than or equal to the preset number A, the first multiple is greater than the third multiple and greater than 1, and the second multiple is less than the fourth multiple and less than 1.

14. An electronic device, characterized in that: The electronic device comprises: a storage device for storing executable instructions; A processing device is used to execute the executable instructions stored in the storage device to implement the multi-dimensional identification method for determining engine combustion failure according to any one of claims 1 to 13.

15. A storage medium, characterized in that: The storage medium stores a computer program, and when the computer program is executed, the method for determining a multi-dimensional engine combustion failure according to any one of claims 1 to 13 is implemented.

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