A method for detecting a rationality fault of periodic oscillation of a gpf differential pressure sensor

Abstract

The application discloses a kind of periodic oscillation rationality fault detection methods of GPF differential pressure sensor, the method includes the following steps, obtains vehicle operating parameter, judges whether current is in steady state condition, and meets stability condition;If yes, subsequent step is carried out, if no, repeat this step;GPF inlet pressure original value and GPF outlet pressure original value are obtained;GPF inlet pressure original value and GPF outlet pressure original value are respectively carried out first-order low-pass filtering processing, and GPF inlet pressure filter value and GPF outlet pressure filter value are obtained;According to GPF inlet pressure filter value and GPF outlet pressure filter value at different time, the interval duration between the extreme values of GPF out / inlet pressure filter value at different time is obtained, according to the interval duration between the extreme values of GPF inlet pressure filter value at different time and the interval duration between the extreme values of GPF outlet pressure filter value at different time, whether GPF differential pressure sensor exists periodic oscillation rationality fault is judged.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of GPF differential pressure sensor fault detection, in particular to a reasonable fault detection method for periodic oscillation of a GPF differential pressure sensor. BACKGROUND

[0002] The emission limit value of automobile exhaust pollutants is further strengthened in the national six emission standards. In order to meet the requirements of particulate matter in automobile exhaust, most of the technical routes of the main machine factory are to install a particulate trap in the exhaust system. The particulate trap can capture more than 90% of the number of particles in the automobile exhaust. However, the captured particulate matter will adhere to the filter body of the trap. With the continuous accumulation of particulate matter, the exhaust resistance of the engine will increase. When the particulate trap is seriously clogged, the engine exhaust system back pressure rises, causing the engine power and economy to deteriorate.

[0003] A particulate trap differential pressure sensor will be installed in the gasoline engine particulate trap (GPF) to read the differential pressure of the trap carrier. The collection of differential pressure is an important input for the estimation of the carbon accumulation in the particulate trap, which determines the accuracy of the estimation of the carbon accumulation in the particulate trap, thereby affecting the accuracy of the regeneration control of the particulate trap. Therefore, it is necessary to detect whether the differential pressure sensor fails in time to avoid false estimation of carbon accumulation and regeneration control accuracy.

[0004] The prior art discloses a particulate trap active regeneration hierarchical control method. However, the prior art does not disclose that if the sensor collecting the differential pressure of the particulate trap fails, it may cause the estimation of carbon accumulation to be wrong, resulting in the phenomenon that the driver is panicked by the false alarm that the carbon accumulation is too high, thereby reducing customer satisfaction. It may also cause the particulate trap to be burned out. SUMMARY

[0005] The purpose of the present application is to provide a reasonable fault detection method for periodic oscillation of a GPF differential pressure sensor to timely and accurately detect the reasonable fault of periodic oscillation of the GPF differential pressure sensor.

[0006] To solve the above technical problems, the present application provides a technical scheme: a reasonable fault detection method for periodic oscillation of a GPF differential pressure sensor, which comprises the following steps,

[0007] Obtain the vehicle operating parameters, determine whether the current is in a steady state condition and meets the stability condition, if yes, proceed to the next step, if not, repeat the step;

[0008] Obtain the GPF inlet pressure original value and the GPF outlet pressure original value; the GPF inlet pressure original value and the GPF outlet pressure original value are obtained by measuring the GPF differential pressure sensor;

[0009] The GPF inlet pressure original value and the GPF outlet pressure original value are respectively subjected to first-order low-pass filtering to obtain a GPF inlet pressure filtered value and a GPF outlet pressure filtered value;

[0010] According to the GPF inlet pressure filtered values and the GPF outlet pressure filtered values at different times, interval durations between extreme values of the GPF inlet pressure filtered values at different times and interval durations between extreme values of the GPF outlet pressure filtered values at different times are obtained;

[0011] According to the interval durations between extreme values of the GPF inlet pressure filtered values at different times and the interval durations between extreme values of the GPF outlet pressure filtered values at different times, it is determined whether the GPF differential pressure sensor has a periodic oscillation rationality fault.

[0012] According to the above scheme, the steady-state working condition determination conditions are as follows,

[0013] 1) The engine is in a running state;

[0014] 2) The engine speed is within a certain range; and after the periodic oscillation rationality fault detection of the GPF differential pressure sensor, the engine speed fluctuation is within a certain range;

[0015] 3) The intake density of fresh air entering the cylinder is within a certain range, and after the periodic oscillation rationality fault detection of the GPF differential pressure sensor, the intake density fluctuation of fresh air entering the cylinder is within a certain range;

[0016] 4) The target air-fuel ratio fluctuation is within a certain range;

[0017] 5) The fluctuation of the difference between the target air-fuel ratio and the actual air-fuel ratio is within a certain range;

[0018] 6) The actual air-fuel ratio fluctuation is within a certain range;

[0019] 7) The GPF body temperature fluctuation is within a certain range;

[0020] 8) The engine water temperature is within a certain range, and after the periodic oscillation rationality fault detection of the GPF differential pressure sensor, the engine water temperature fluctuation is within a certain range;

[0021] 9) The intake temperature is within a certain range, and after the periodic oscillation rationality fault detection of the GPF differential pressure sensor, the intake temperature fluctuation is within a certain range;

[0022] 10) The ignition angle efficiency fluctuation is within a certain range;

[0023] 11) No knock occurs, and no pre-ignition occurs;

[0024] 12) engine oil breakage does not occur;

[0025] 13) both the pre-catalyst oxygen sensor and the post-catalyst oxygen sensor have completed heating activation;

[0026] 14) the atmospheric pressure fluctuation amount is within a certain range;

[0027] 15) misfire failure does not occur;

[0028] 16) GPF differential pressure sensor electrical failure does not occur;

[0029] 17) GPF temperature sensor failure does not occur;

[0030] 18) periodic oscillation rationality failure of the GPF differential pressure sensor is not detected in the current vehicle driving cycle;

[0031] When the above conditions are met at the same time, it is determined that the steady state condition is reached.

[0032] According to the above scheme, the stability condition is that the time continuously in the steady state condition exceeds a certain length of time.

[0033] According to the above scheme, the GPF inlet pressure filtering value and the GPF outlet pressure filtering value are obtained as follows, GPFInletFilter (N) = K GPFInlet × [p GPFInlet (N) - p GPFInletFilter (N-1)] + p GPFInletFilter (N-1) GPFOutletFilter (N) = K GPFOutlet × [p GPFOutlet (N) - p GPFOutletFilter (N-1)] + p GPFOutletFilter (N-1)

[0034] In the formula, p GPFInlet (N) is the original value of the GPF inlet pressure in the Nth sampling period, p GPFInletFilter (N) is the filtering value of the GPF inlet pressure in the Nth sampling period, p GPFInletFilter (N-1) is the filtering value of the GPF inlet pressure in the (N-1)th sampling period; p GPFOutlet (N) is the original value of the GPF outlet pressure in the Nth sampling period, p GPFInletFilter (N) is the filtering value of the GPF outlet pressure in the Nth sampling period, p GPFOutletFilter (N-1) is the filtering value of the GPF outlet pressure in the (N-1)th sampling period; N is a positive integer; the sampling period interval is Δt; K GPFInlet is the GPF inlet pressure filtering coefficient, K GPFOutletis the GPF outlet pressure filtering coefficient, and satisfies

[0035]

[0036]

[0037] In the above formula, m is the number of engine cylinders, n is the engine speed, and f1(n) and f2(n) are both calibrated based on the engine speed.

[0038] According to the above scheme, the process of judging whether the GPF differential pressure sensor has a reasonable fault of periodic oscillation is as follows according to the interval time length between the extreme values of the GPF inlet pressure filtering values at different times and the interval time length between the extreme values of the GPF outlet pressure filtering values at different times.

[0039] The time interval between the maximum value of the GPF inlet pressure filtering value of a sampling period and the maximum value of the GPF inlet pressure filtering value of the previous sampling period of the sampling period is recorded as the adjacent maximum value time interval t GPFInletMaxInterval of the GPF inlet pressure filtering value of the sampling period. GPFInletMinInterval ;

[0040] The adjacent maximum value time interval t GPFInletMaxInterval of the GPF inlet pressure filtering value and the adjacent minimum value time interval t GPFInletMinInterval of the GPF inlet pressure filtering value of different sampling periods are used to calculate the average value of the adjacent maximum value time interval t of the GPF inlet pressure filtering value and the average value of the adjacent minimum value time interval t

[0041] If the following condition is met,

[0042]

[0043] it is judged that the GPF differential pressure sensor has a reasonable fault of periodic oscillation, where r MaxDiffLimit is a preset value (in this embodiment, the value is 1.25);

[0044] The time interval between the maximum value of the GPF outlet pressure filtering value of a sampling period and the maximum value of the GPF outlet pressure filtering value of the previous sampling period of the sampling period is recorded as the adjacent maximum value time interval t GPFOutletMaxIntervalThe time interval between the minimum value of the GPF outlet pressure filtered value of a sampling period and the minimum value of the GPF outlet pressure filtered value of the last sampling period of the sampling period is recorded as the GPF outlet pressure filtered value adjacent minimum value time interval t GPFOutletMinInterval ;

[0045] According to the GPF outlet pressure filtered value adjacent maximum value time interval t GPFOutletMaxInterval , the GPF outlet pressure filtered value adjacent minimum value time interval t GPFOutletMinInterval , the GPF outlet pressure filtered value adjacent maximum value time interval average value The GPF outlet pressure filtered value adjacent minimum value time interval

[0046] If the following condition is met,

[0047]

[0048] It is judged that the GPF differential pressure sensor has a reasonable fault of periodic oscillation.

[0049] According to the GPF inlet pressure filtered value adjacent maximum value time interval average value The GPF inlet pressure filtered value adjacent minimum value time interval The GPF inlet pressure oscillation period t GPFInletCycle is obtained, specifically;

[0050]

[0051] According to the GPF outlet pressure filtered value adjacent maximum value time interval average value The GPF outlet pressure filtered value adjacent minimum value time interval The GPF outlet pressure oscillation period t GPFOutletCycle is obtained, specifically;

[0052]

[0053] If the following condition is met;

[0054]

[0055] It is judged that the GPF differential pressure sensor has a reasonable fault of periodic oscillation, wherein f(T GPFBrick , r GPFSoot ) is determined by the GPF body temperature T GPFBrick and the cumulative carbon content coefficient r GPFSoot , and the cumulative carbon content coefficient r GPFSoot is obtained according to the GPF current actual carbon content m_Soot and the GPF carbon load capacity upper limit value m_SootCapacity, specifically r Adpat r is the self-learning correction coefficient. Adpat Its initial value is 0 and it is updated based on self-learning, and is saved after the vehicle is powered off.

[0056] According to the above scheme, the average time interval between adjacent maxima of the GPF inlet pressure filter value is... Average value of adjacent minimum values ​​of GPF inlet pressure filter The specific process of obtaining it is as follows;

[0057] If the time interval between adjacent maxima of the GPF inlet pressure filter value in the current sampling period is t GPFInletMaxInterval Less than a preset value A 11 And the current sampling period t GPFInletMaxInterval t of other sampling periods GPFInletMaxInte rval The time difference is less than a preset value B. 11 Then the current sampling period t will be... GPFInletMaxInterval Remove it so that it does not participate. The calculation of A; where A 11 Related to engine speed n, B 11 For other sampling periods t GPFInletMaxInte rval A certain multiple of the average value; if during the continuous sampling of GPF inlet / outlet pressure, the time interval t between adjacent maxima of the GPF inlet pressure filter value in the current sampling period... GPFInletMaxInterval Less than the preset value A 11 "The cumulative number of occurrences has exceeded the preset number CNT" 11 If so, it can be determined that the GPF differential pressure sensor has a reasonable fault of periodic oscillation;

[0058] If the time interval between adjacent maxima of the GPF inlet pressure filter value in the current sampling period is t GPFInletMaxInterval Greater than a preset value A 21 And the current sampling period t GPFInletMaxInterval t of other sampling periods GPFInletMaxInte rval The time difference is greater than a preset value B. 21 Then the current sampling period t will be... GPFInletMaxInterval Remove it so that it does not participate. The calculation of A; where A 21 Related to engine speed n, B 21 For other sampling periods t GPFInletMaxInte rval A certain multiple of the average value; if during the continuous sampling of GPF inlet / outlet pressure, the time interval t between adjacent maxima of the GPF inlet pressure filter value in the current sampling period... GPFInletMaxInterval Greater than the preset value A 21 "The cumulative number of occurrences has exceeded the preset number CNT" 21If so, it can be determined that the GPF differential pressure sensor has a reasonable fault of periodic oscillation;

[0059] The remaining sampling period t after elimination GPFInletMaxInterval Take the average, and get

[0060] If the time interval t between adjacent minimum values ​​of the GPF inlet pressure filter value in the current sampling period is... GPFInletMinInterval Less than a preset value A 31 And the current sampling period t GPFInletMinInterval t of other sampling periods GPFInletMinInterval The time difference is less than a preset value B. 31 Then the current sampling period t will be... GPFInletMinInterval Remove it so that it does not participate. The calculation of A; where A 31 Related to engine speed n, B 31 For other sampling periods t GPFInletMinInterval A certain multiple of the average value; if during the continuous sampling of GPF inlet / outlet pressure, the time interval t between adjacent maxima of the GPF inlet pressure filter value in the current sampling period... GPFInletMinInterval Less than the preset value A 31 "The cumulative number of occurrences has exceeded the preset number CNT" 31 If so, it can be determined that the GPF differential pressure sensor has a reasonable fault of periodic oscillation;

[0061] If the time interval t between adjacent minimum values ​​of the GPF inlet pressure filter value in the current sampling period is... GPFInletMinInterval Greater than a preset value A 41 And the current sampling period t GPFInletMinInterval t of other sampling periods GPFInletMinInterval The time difference is greater than a preset value B. 41 Then the current sampling period t will be... GPFInletMinInterval Remove it so that it does not participate. The calculation of A; where A 41 Related to engine speed n, B 41 For other sampling periods t GPFInletMinInterval A certain multiple of the average value; if during the continuous sampling of GPF inlet / outlet pressure, the time interval t between adjacent maxima of the GPF inlet pressure filter value in the current sampling period... GPFInletMinInterval Greater than the preset value A 41 "The cumulative number of occurrences has exceeded the preset number CNT" 41 If so, it can be determined that the GPF differential pressure sensor has a reasonable fault of periodic oscillation;

[0062] The remaining sampling period t after elimination GPFInletMinInterval Take the average, and get

[0063] According to the above scheme, the average time interval between adjacent maxima of the GPF outlet pressure filter value is... Average value of adjacent minimum values ​​of GPF outlet pressure filter value The specific process of obtaining it is as follows;

[0064] If the time interval between adjacent maxima of the GPF outlet pressure filter value in the current sampling period is t GPFOutletMaxInterval Less than a preset value A 12 And the current sampling period t GPFOutletMaxInterval t of other sampling periods GPFOutletMaxInterval The time difference is less than a preset value B. 12 Then the current sampling period t will be... GPFOutletMaxInterval Remove it so that it does not participate. The calculation of A; where A 12 Related to engine speed n, B 12 For other sampling periods t GPFOutletMaxInterval A certain multiple of the average value; if during the continuous sampling of GPF inlet / outlet pressure, the time interval t between adjacent maxima of the GPF outlet pressure filter value in the current sampling period... GPFOutletMaxInterval Less than the preset value A 12 "The cumulative number of occurrences has exceeded the preset number CNT" 12 If so, it can be determined that the GPF differential pressure sensor has a reasonable fault of periodic oscillation;

[0065] If the time interval between adjacent maxima of the GPF outlet pressure filter value in the current sampling period is t GPFOutletMaxInterval Greater than a preset value A 22 And the current sampling period t GPFOutletMaxInterval t of other sampling periods GPFOutletMaxInterval The time difference is greater than a preset value B. 22 Then the current sampling period t will be... GPFOutletMaxInterval Remove it so that it does not participate. The calculation of A; where A 22 Related to engine speed n, B 22 For other sampling periods t GPFOutletMaxInterval A certain multiple of the average value; if during the continuous sampling of GPF inlet / outlet pressure, the time interval t between adjacent maxima of the GPF outlet pressure filter value in the current sampling period... GPFOutletMaxInterval Greater than the preset value A 22 "The cumulative number of occurrences has exceeded the preset number CNT" 22 If so, it can be determined that the GPF differential pressure sensor has a reasonable fault of periodic oscillation;

[0066] The remaining sampling period t after eliminationGPFOutletMaxInterval Taking the average value, we get

[0067] If the adjacent minimum time interval t GPFOutletMinInterval of the GPF outlet pressure filtered value of the current sampling period is less than a preset value A 32 , and the time difference between the t GPFOutletMinInterval of the current sampling period and the t GPFOutletMinInterval of other sampling periods is less than a preset value B 32 , then the t GPFOutletMinInterval of the current sampling period is rejected so as not to participate in the calculation of ; wherein A 32 is related to the engine speed n, and B 32 is a certain multiple of the average value of the t GPFOutletMinInterval of other sampling periods; if the number of occurrences of the event "the adjacent maximum time interval t GPFOutletMinInterval of the GPF outlet pressure filtered value of the current sampling period is less than the preset value A 32 " accumulates more than a preset number CNT 32 during the continuous sampling of the GPF outlet / inlet pressure, it is determined that the GPF differential pressure sensor has a reasonable fault of periodic oscillation;

[0068] If the adjacent minimum time interval t GPFOutletMinInterval of the GPF outlet pressure filtered value of the current sampling period is greater than a preset value A 42 , and the time difference between the t GPFOutletMinInterval of the current sampling period and the t GPFInletMinInterval of other sampling periods is greater than a preset value B 42 , then the t GPFOutletMinInterval of the current sampling period is rejected so as not to participate in the calculation of ; wherein A 42 is related to the engine speed n, and B 42 is a certain multiple of the average value of the t GPFOutletMinInterval of other sampling periods; if the number of occurrences of the event "the adjacent maximum time interval t GPFOutletMinInterval of the GPF inlet pressure filtered value of the current sampling period is greater than the preset value A 42 " accumulates more than a preset number CNT 42 during the continuous sampling of the GPF outlet / inlet pressure, it is determined that the GPF differential pressure sensor has a reasonable fault of periodic oscillation;

[0069] Taking the average value of the remaining sampling periods t GPFOutletMinInterval after rejection, we get

[0070] According to the above scheme, the self-learning update process of the self-learning correction coefficient r Adpat is as follows;

[0071] determining whether the current is in the self-learning working condition, if yes, reading the accumulated carbon amount coefficient r at the initial time in the self-learning working condition GPFSootBegin , and obtaining the value of the accumulated carbon amount coefficient r GPFSoot The time length t1 when the value of the accumulated carbon amount coefficient r GPFSootBegin changes to 0;

[0072] According to t1, T GPFBrick , r GPFSootBegin , the self-learning correction coefficient r Adpat is updated.

[0073] According to the above scheme, the self-learning working condition determination condition is specifically as follows,

[0074] a) the engine is in a running state;

[0075] b) the engine speed fluctuation is within a certain range;

[0076] c) the vehicle speed exceeds a certain value;

[0077] d) the accumulated carbon amount coefficient r GPFSoot does not exceed a certain value;

[0078] e) the GPF body temperature is not lower than a certain value;

[0079] f) the intake density fluctuation of fresh air entering the cylinder is within a certain range;

[0080] g) the target air-fuel ratio fluctuation is within a certain range;

[0081] h) the difference between the target air-fuel ratio and the actual air-fuel ratio fluctuation is within a certain range;

[0082] i) the actual air-fuel ratio fluctuation is within a certain range;

[0083] j) the engine water temperature is within a certain range, and after the rationality fault detection of the periodic oscillation entering the GPF differential pressure sensor, the engine water temperature fluctuation is within a certain range;

[0084] k) the intake temperature is within a certain range, and after the rationality fault detection of the periodic oscillation entering the GPF differential pressure sensor, the intake temperature fluctuation is within a certain range;

[0085] l) the ignition angle efficiency fluctuation is within a certain range;

[0086] m) knock does not occur, and pre-ignition does not occur;

[0087] n) the GPF body temperature fluctuation is within a certain range;

[0088] o) Both the oxygen sensor before and after the catalyst have been activated by heating.

[0089] p) Atmospheric pressure fluctuations are within a certain range;

[0090] q) No fire malfunction occurred;

[0091] r) No electrical fault occurred in the GPF differential pressure sensor;

[0092] s) No GPF temperature sensor malfunction occurred;

[0093] t) The absence of a reasonable fault in the periodic oscillation of the GPF differential pressure sensor during this vehicle driving cycle;

[0094] When all of the above conditions are met, the device is determined to be in self-learning mode.

[0095] According to the above scheme, based on t1 and T GPFBrick r GPFSootBegin For the self-learning correction coefficient r Adpat The update process is as follows;

[0096] If t1>t Base ×f1(r GPFSootBegin ,T GPFBrick ), where t Base Based on the time, f1(r) GPFSootBegin ,T GPFBrick According to T GPFBrick r GPFSootBegin The calibration yields r; Adpat The update method is, r Adpat =r Adpat (z)-k1×f1(r GPFS oo tBegin ,T GPFBrick ); where k1 is the first gain coefficient, r Adpat (z) represents the self-learning correction coefficient stored in the last update;

[0097] If t1 <t Base ×f2(r GPFSootBegin ,T GPFBrick ), where f2(r GPFSootBegin ,T GPFBrick According to T GPFBrick r GPFSootBegin The calibration yields r; Adpat The update method is, r Adpat =r Adpat (z)-k2×f2(r GPFSootBegin ,T GPFBrick ); where k2 is the second gain coefficient;

[0098] If t Base ×f2(r GPFSootBegin ,T GPFBrick ) <t1<t Base ×f1(r GPFSootBegin ,T GPFBrick ), then r Adpat The number of times this condition is met remains unchanged; If it exceeds a certain number of times, then r Adpat =r Adpat (z)+k3; where k3 is the third gain coefficient; The count update method is as follows: when the condition is met...

[0099] t Base ×f2(r GPFSootBegin ,T GPFBrick ) <t1<t Base ×f1(r GPFSootBegin ,T GPFBrick The condition is incremented by one, and it is added in each driving cycle. At most one more, when r Adpat After the update Reset to zero.

[0100] The beneficial effects of this invention are: it can make fault judgments in real time based on the fluctuation of GPF pressure signal and update the fault threshold in real time, so as to detect faults in a timely and accurate manner. Attached Figure Description

[0101] Figure 1 This is a flowchart of the rationality fault detection method for the periodic oscillation of the GPF differential pressure sensor according to Embodiment 1 of the present invention. Detailed Implementation

[0102] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0103] Example 1:

[0104] The GPF pressure difference sensor is used to monitor the pressure difference of the gas at the inlet and outlet of the particulate filter carrier, and sensor failure refers to the abnormal working performance of the sensor, which cannot accurately read the pressure difference of the particulate filter carrier. The sensor failure includes electrical faults and rationality faults of the sensor. The electrical faults include open circuit, short circuit and open circuit of the wire harness. The rationality fault refers to the unreasonable signal fault other than the electrical fault.

[0105] The engine exhaust side system structure is sequentially connected with a pre-catalyst oxygen sensor, a catalyst, a post-catalyst oxygen sensor, a GPF, and a sensor for detecting the pressure difference between the inlet and outlet of the GPF. The GPF pressure difference sensor can detect the GPF inlet absolute pressure signal and the GPF outlet absolute pressure signal. The present application detects the failure of the GPF pressure difference sensor and detects its rationality fault. The rationality fault of the present application does not necessarily cover all rationality faults, but only one of them, which is called periodic oscillation rationality fault detection. Since the engine is a non-continuous time injection and ignition of each cylinder, if the pressure sensor signal is normal, it will cause the original pressure signal of the exhaust system to fluctuate periodically. Based on the phenomenon of periodic fluctuation of the original exhaust pressure signal, the GPF pressure difference sensor signal is detected, which is called periodic oscillation rationality fault detection, and the specific detection method is as follows.

[0106] Referring to Figure 1 A periodic oscillation rationality fault detection method for a GPF pressure difference sensor, the method comprising the following steps,

[0107] Obtain the vehicle operating parameters, and determine whether the current is in a steady state condition and meets the stability condition; if yes, proceed to the next step, if not, repeat the step;

[0108] Obtain the GPF inlet pressure original value and the GPF outlet pressure original value; the GPF inlet pressure original value and the GPF outlet pressure original value are measured by the GPF pressure difference sensor;

[0109] The GPF inlet pressure original value and the GPF outlet pressure original value are respectively subjected to first-order low-pass filtering to obtain the GPF inlet pressure filtered value and the GPF outlet pressure filtered value;

[0110] According to the GPF inlet pressure filtered value and the GPF outlet pressure filtered value at different times, the interval time length between the extreme values of the GPF inlet pressure filtered value at different times and the interval time length between the extreme values of the GPF outlet pressure filtered value at different times are obtained;

[0111] According to the interval length between the extreme values of the GPF inlet pressure filtering values at different times and the interval length between the extreme values of the GPF outlet pressure filtering values at different times, the rationality of the periodic oscillation of the GPF differential pressure sensor is judged.

[0112] Further, the steady state working condition judgment condition is specifically as follows,

[0113] 1) the engine is in a running state;

[0114] 2) the engine speed is within a certain range (600 rpm to 5900 rpm in this example); and after the periodic oscillation rationality fault detection of the GPF differential pressure sensor, the engine speed fluctuation is within a certain range (±15 rpm in this example);

[0115] 3) the intake density of fresh air into the cylinder (i.e. load) is within a certain range (200 mgpl to 3000 mgpl in this example), and after the periodic oscillation rationality fault detection of the GPF differential pressure sensor, the intake density fluctuation of fresh air into the cylinder is within a certain range (±20 mgpl in this example);

[0116] 4) the target air-fuel ratio fluctuation is within a certain range (±0.1 in this example);

[0117] 5) the fluctuation of the difference between the target air-fuel ratio and the actual air-fuel ratio is within a certain range (±0.1 in this example);

[0118] 6) the actual air-fuel ratio fluctuation is within a certain range (±0.1 in this example);

[0119] 7) the GPF body temperature fluctuation is within a certain range (±5℃ in this example);

[0120] 8) the engine water temperature is within a certain range (0℃ to 100℃ in this example), and after the periodic oscillation rationality fault detection of the GPF differential pressure sensor, the engine water temperature fluctuation is within a certain range (±2℃ in this example);

[0121] 9) the intake temperature is within a certain range (30℃ to 80℃ in this example), and after the periodic oscillation rationality fault detection of the GPF differential pressure sensor, the intake temperature fluctuation is within a certain range (±1.5℃ in this example);

[0122] 10) the ignition angle efficiency fluctuation is within a certain range (±0.1 in this example);

[0123] 11) no knock occurs, and no pre-ignition occurs;

[0124] 12) no engine oil break occurs;

[0125] 13) both pre-catalytic oxygen sensor and post-catalytic oxygen sensor have completed heating activation;

[0126] 14) atmospheric pressure fluctuation is within a certain range (±0.5kPa in this example);

[0127] 15) misfire fault does not occur;

[0128] 16) GPF differential pressure sensor electrical fault does not occur;

[0129] 17) GPF temperature sensor fault does not occur;

[0130] 18) periodic oscillation rationality fault of GPF differential pressure sensor is not detected in this vehicle driving cycle;

[0131] When the above conditions are met at the same time, it is determined that it is in a steady state working condition.

[0132] Further, the stability condition is that the time of continuously being in a steady state working condition exceeds a certain length of time (5s in this example).

[0133] Further, the GPF inlet pressure filtered value and the GPF outlet pressure filtered value are obtained as follows,

[0134] p GPFInletFilter (N) = K GPFInlet × [p GPFInlet (N) - p GPFInletFilter (N-1)] + p GPFInletFilter (N-1)

[0135] p GPFOutletFilter (N) = K GPFOutlet × [p GPFOutlet (N) - p GPFOutletFilter (N-1)] + p GPFOutletFilter (N-1)

[0136] In the formula, p GPFInlet (N) is the original value of the GPF inlet pressure in the Nth sampling period, p GPFInletFilter (N) is the filtered value of the GPF inlet pressure in the Nth sampling period, p GPFInletFilter (N-1) is the filtered value of the GPF inlet pressure in the (N-1)th sampling period; p GPFOutlet (N) is the original value of the GPF outlet pressure in the Nth sampling period, p GPFInletFilter (N) is the filtered value of the GPF outlet pressure in the Nth sampling period, p GPFOutletFilter (N-1) is the filtered value of the GPF outlet pressure in the (N-1)th sampling period; N is a positive integer; and in particular, p GPFInletFilter(0) is equal to the original value of the GPF inlet pressure at the 0th sampling period p GPFInlet (0), p GPFOutletFilter (0) is equal to the original value of the GPF outlet pressure at the 0th sampling period p GPFOutlet (0); the sampling period interval is Δt (1 ms in this embodiment); K GPFInlet is a GPF inlet pressure filtering coefficient, K GPFOutlet is a GPF outlet pressure filtering coefficient, and satisfies,

[0137]

[0138]

[0139] In the above formula, m is the number of engine cylinders, n is the engine speed, f1(n) and f2(n) are both calibrated based on the engine speed;

[0140] The specific calibration is as follows:

[0141]

[0142] Further, according to the interval length between the extreme values of the GPF inlet pressure filtering values at different times, and the interval length between the extreme values of the GPF outlet pressure filtering values at different times, the process of judging whether the GPF differential pressure sensor has a periodic oscillation reasonable fault is as follows:

[0143] The time interval between the maximum value of the GPF inlet pressure filtering value of a sampling period and the maximum value of the GPF inlet pressure filtering value of the previous sampling period of the sampling period is recorded as the GPF inlet pressure filtering value adjacent maximum value time interval t GPFInletMaxInterval of the sampling period; the time interval between the minimum value of the GPF inlet pressure filtering value of a sampling period and the minimum value of the GPF inlet pressure filtering value of the previous sampling period of the sampling period is recorded as the GPF inlet pressure filtering value adjacent minimum value time interval t GPFInletMinInterval ;

[0144] According to the GPF inlet pressure filtering value adjacent maximum value time interval t GPFInletMaxInterval , the GPF inlet pressure filtering value adjacent minimum value time interval t GPFInletMinInterval of different sampling periods, the GPF inlet pressure filtering value adjacent maximum value time interval average value and the GPF inlet pressure filtering value adjacent minimum value time interval average value

[0145] If,

[0146]

[0147] then the rationality fault of periodic oscillation of the GPF differential pressure sensor is judged, wherein r MaxDiffLimit is a preset value;

[0148] The time interval between the maximum value of the GPF outlet pressure filtered value of a sampling period and the maximum value of the GPF outlet pressure filtered value of the last sampling period of the sampling period is recorded as the GPF outlet pressure filtered value adjacent maximum value time interval t GPFOutletMaxInterval of the sampling period; the time interval between the minimum value of the GPF outlet pressure filtered value of a sampling period and the minimum value of the GPF outlet pressure filtered value of the last sampling period of the sampling period is recorded as the GPF outlet pressure filtered value adjacent minimum value time interval t GPFOutletMinInterval ;

[0149] According to the GPF outlet pressure filtered value adjacent maximum value time interval t GPFOutletMaxInterval , the GPF outlet pressure filtered value adjacent minimum value time interval t GPFOutletMinInterval of different sampling periods, the GPF outlet pressure filtered value adjacent maximum value time interval average value GPF outlet pressure filtered value adjacent minimum value time interval

[0150] If

[0151]

[0152] then the rationality fault of periodic oscillation of the GPF differential pressure sensor is judged;

[0153] According to the GPF inlet pressure filtered value adjacent maximum value time interval average value GPF inlet pressure filtered value adjacent minimum value time interval , the GPF inlet pressure oscillation period t GPFInletCycle is obtained, and specifically;

[0154]

[0155] According to the GPF outlet pressure filtered value adjacent maximum value time interval average value GPF outlet pressure filtered value adjacent minimum value time interval , the GPF outlet pressure oscillation period t GPFOutletCycle is obtained, and specifically;

[0156]

[0157] If

[0158]

[0159] Then it is determined that the GPF differential pressure sensor has a reasonable fault of periodic oscillation, where f(T) GPFBrick ,r GPFSoot The temperature T of the GPF body GPFBrick And cumulative carbon coefficient r GPFSoot Determined jointly; in this embodiment, f(T) GPFBrick ,r GPFSoot The calibration data is as follows:

[0160]

[0161] Cumulative carbon coefficient r GPFSoot This is obtained based on the current actual carbon content m_Soot of the GPF and the upper limit value m_SootCapacity of the GPF carbon loading. (cumulative carbon coefficient r) GPFSoot The calculation method is described in existing technologies CN201710858110.5 "Estimation Method for Cumulative Carbon Content of Diesel Vehicle Particulate Filter" and CN201811574677.0 "A Graded Control Method and Control System for Deceleration Fuel Cut-off Regeneration of Gasoline Engine Particulate Filter"; r Adpat r is the self-learning correction coefficient. Adpat Its initial value is 0 and it is updated based on self-learning, and is saved after the vehicle is powered off.

[0162] Furthermore, the average time interval between adjacent maxima of the GPF inlet pressure filter value. Average value of adjacent minimum values ​​of GPF inlet pressure filter The specific process of obtaining it is as follows;

[0163] If the time interval between adjacent maxima of the GPF inlet pressure filter value in the current sampling period is t GPFInletMaxInterval Less than a preset value A 11 And the current sampling period t GPFInletMaxInterval t of other sampling periods GPFInletMaxInterval The time difference is less than a preset value B. 11 Then the current sampling period t will be... GPFInletMaxInterval Remove it so that it does not participate. The calculation of A; where A 11 Related to engine speed n, B 11 For other sampling periods t GPFInletMaxInterval A certain multiple of the average value (0.8 times in this embodiment); if during the continuous sampling of GPF inlet / outlet pressure, the event "the time interval t between adjacent maxima of the GPF inlet pressure filter value in the current sampling period" occurs. GPFInletMaxInterval Less than the preset value A 11 "The cumulative number of occurrences has exceeded the preset number CNT" 11(In this embodiment, 1000 times are taken), then it is determined that the GPF differential pressure sensor has a reasonable fault of periodic oscillation;

[0164] Where A 11 The calibration process is as follows:

[0165]

[0166] If the time interval between adjacent maxima of the GPF inlet pressure filter value in the current sampling period is t GPFInletMaxInterval Greater than a preset value A 21 And the current sampling period t GPFInletMaxInterval t of other sampling periods GPFIn l etMaxInte rval The time difference is greater than a preset value B. 21 Then the current sampling period t will be... GPFInletMaxInterval Remove it so that it does not participate. The calculation of A; where A 21 Related to engine speed n, B 21 For other sampling periods t GPFInletMaxInte rval A certain multiple of the average value (1.2 times in this embodiment); if during the continuous sampling of GPF inlet / outlet pressure, the event "the time interval t between adjacent maxima of the GPF inlet pressure filter value in the current sampling period" occurs. GPFInletMaxInterval Greater than the preset value A 21 "The cumulative number of occurrences has exceeded the preset number CNT" 21 (In this example, 1000 times) is taken, then it is determined that the GPF differential pressure sensor has a reasonable fault of periodic oscillation;

[0167] Where A 21 The calibration process is as follows:

[0168]

[0169] The remaining sampling period t after elimination GPFInletMaxInterval Take the average, and get

[0170] If the time interval t between adjacent minimum values ​​of the GPF inlet pressure filter value in the current sampling period is... GPFInletMinInterval Less than a preset value A 31 And the current sampling period t GPFInletMinInterval t of other sampling periods GPFInletMinInterval The time difference is less than a preset value B. 31 Then the current sampling period t will be... GPFInletMinInterval Remove it so that it does not participate. The calculation of A; where A 31 Related to engine speed n, B 31 For other sampling periods tGPFInletMinInterval a certain multiple of the average value of t GPFInletMinInterval is less than a preset value A 31 , the number of occurrences of the event "the adjacent maximum value time interval t 31 of the GPF inlet pressure filter value of the current sampling period is greater than a preset value A

[0171] The calibration process of A 31 is as follows:

[0172]

[0173] If the adjacent minimum value time interval t GPFInletMinInterval of the GPF inlet pressure filter value of the current sampling period is greater than a preset value A 41 , and the time difference between t GPFInletMinInterval of the current sampling period and t GPFInletMinInterval of other sampling periods is greater than a preset value B 41 , then t GPFInletMinInterval of the current sampling period is rejected so as not to participate in the calculation of t ; wherein A 41 is related to the engine speed n, and B 41 is a certain multiple of the average value of t GPFInletMinInterval of other sampling periods (1.2 times in this embodiment); if the number of occurrences of the event "the adjacent maximum value time interval t GPFInletMinInterval of the GPF inlet pressure filter value of the current sampling period is greater than a preset value A 41 " accumulates more than a preset number of times CNT 41 (1000 times in this embodiment), it is determined that the GPF differential pressure sensor has a reasonable fault of periodic oscillation;

[0174] The calibration process of A 41 is as follows:

[0175]

[0176] The average value of t GPFInletMinInterval of the remaining sampling periods after rejection is obtained as t

[0177] Further, the average value of the adjacent maximum value time interval of the GPF outlet pressure filter value is t The average value of the adjacent minimum value time interval of the GPF outlet pressure filter value is t The acquisition process is as follows:

[0178] If the time interval t GPFOutletMaxInterval of the adjacent maximum values of the GPF outlet pressure filtered value in the current sampling period is less than a preset value A 12 , and the time difference between t GPFOutletMaxInterval of the current sampling period and t GPFOutletMaxInterval of other sampling periods is less than a preset value B 12 , then t GPFOutletMaxInterval of the current sampling period is rejected so as not to participate in the calculation of the average value of t ; wherein A 12 is related to the engine speed n, and B 12 is a certain multiple (0.8 times in the embodiment) of the average value of t GPFOutletMaxInterval of other sampling periods; if the number of occurrences of the event “the time interval t GPFOutletMaxInterval of the adjacent maximum values of the GPF outlet pressure filtered value in the current sampling period is less than the preset value A 12 ” accumulates more than a preset number CNT 12 (1000 times in the embodiment) in the process of continuous sampling of the GPF outlet / inlet pressure, it is determined that the GPF differential pressure sensor has a reasonable fault of periodic oscillation;

[0179] The calibration process of A 12 is as follows:

[0180]

[0181] If the time interval t GPFOutletMaxInterval of the adjacent maximum values of the GPF outlet pressure filtered value in the current sampling period is greater than a preset value A 22 , and the time difference between t GPFOutletMaxInterval of the current sampling period and t GPFOutletMaxInterval of other sampling periods is greater than a preset value B 22 , then t GPFOutletMaxInterval of the current sampling period is rejected so as not to participate in the calculation of the average value of t ; wherein A 22 is related to the engine speed n, and B 22 is a certain multiple (1.2 times in the embodiment) of the average value of t GPFOutletMaxInterval of other sampling periods; if the number of occurrences of the event “the time interval t GPFOutletMaxInterval of the adjacent maximum values of the GPF outlet pressure filtered value in the current sampling period is greater than the preset value A 22 ” accumulates more than a preset number CNT 22 (1000 times in the embodiment) in the process of continuous sampling of the GPF outlet / inlet pressure, it is determined that the GPF differential pressure sensor has a reasonable fault of periodic oscillation;

[0182] The calibration process of A 22 is as follows:

[0183]

[0184] t GPFOutletMaxInterval

[0185] If the adjacent minimum time interval t GPFOutletMinInterval of the GPF outlet pressure filtered value of the current sampling period is less than a preset value A 32 , and the time difference between the current sampling period t GPFOutletMinInterval and other sampling periods t GPFOutletMinInterval is less than a preset value B 32 , the current sampling period t GPFOutletMinInterval is eliminated so as not to participate in the calculation of the average value of t ; wherein A 32 is related to the engine speed n, and B 32 is a certain multiple (0.8 times in the embodiment) of the average value of t GPFOutletMinInterval of other sampling periods; if the number of times of the event “the adjacent maximum time interval t GPFOutletMinInterval of the GPF outlet pressure filtered value of the current sampling period is less than the preset value A 32 ” exceeds a preset number CNT 32 (1000 times in the embodiment) in the continuous sampling process of the GPF outlet / inlet pressure, it is judged that the GPF pressure difference sensor has a periodic oscillation rationality fault.

[0186] A 32 The calibration process is as follows:

[0187]

[0188] If the adjacent minimum time interval t GPFOutletMinInterval of the GPF outlet pressure filtered value of the current sampling period is greater than a preset value A 42 , and the time difference between the current sampling period t GPFOutletMinInterval and other sampling periods t GPFInletMinInterval is greater than a preset value B 42 , the current sampling period t GPFOutletMinInterval is eliminated so as not to participate in the calculation of the average value of t ; wherein A 42 is related to the engine speed n, and B 42 is a certain multiple (1.2 times in the embodiment) of the average value of t GPFOutletMinInterval of other sampling periods; if the number of times of the event “the adjacent maximum time interval t GPFOutletMinInterval of the GPF inlet pressure filtered value of the current sampling period is greater than the preset value A​42 the number of times of occurrence exceeds a preset number CNT 42 (1000 times in this embodiment), it is determined that the GPF differential pressure sensor has a periodic oscillation rationality fault;

[0189] A 42 The calibration process is as follows:

[0190]

[0191] The remaining sampling periods t GPFOutletMinInterval after the elimination are taken as the average to obtain

[0192] Further, the self-learning correction coefficient r Adpat is updated as follows:

[0193] It is determined whether the current is in the self-learning working condition, and if so, the cumulative carbon content coefficient r GPFSootBegin at the initial time in the self-learning working condition is read, and the value of the cumulative carbon content coefficient r GPFSoot is obtained, which is the time length t1 from when r GPFSootBegin changes to 0.

[0194] The self-learning correction coefficient r GPFBrick is updated according to t1, T GPFSootBegin , and r Adpat .

[0195] Further, the self-learning working condition determination condition is as follows:

[0196] a) the engine is in a running state;

[0197] b) the engine speed fluctuation is within a certain range (±15 rpm in this example);

[0198] c) the vehicle speed exceeds a certain value (70 km / h in this example);

[0199] d) the cumulative carbon content coefficient r GPFSoot does not exceed a certain value (0.1 in this example);

[0200] e) the GPF body temperature is not lower than a certain value (610°C in this example);

[0201] f) the intake density fluctuation of fresh air entering the cylinder is within a certain range (±20 mgpl in this example);

[0202] g) the target air-fuel ratio fluctuation is within a certain range (±0.1 in this example);

[0203] h) the difference between the target air-fuel ratio and the actual air-fuel ratio fluctuation is within a certain range (± 0.1);

[0205] i) the actual air-fuel ratio fluctuation is within a certain range (±0.1 in this example);

[0206] j) the engine water temperature is within a certain range (0-100°C in this example), and after the rationality fault detection of the periodic oscillation of the GPF differential pressure sensor, the engine water temperature fluctuation is within a certain range (±2°C in this example);

[0207] k) the intake air temperature is within a certain range (30-80°C in this example), and after the rationality fault detection of the periodic oscillation of the GPF differential pressure sensor, the intake air temperature fluctuation is within a certain range (±1.5°C in this example);

[0208] l) the ignition angle efficiency fluctuation is within a certain range (±0.1 in this example);

[0209] m) no knock and no pre-ignition;

[0210] n) the GPF body temperature fluctuation is within a certain range (±3°C in this example);

[0211] o) both the pre-catalyst oxygen sensor and the post-catalyst oxygen sensor have completed the heating activation;

[0212] p) the atmospheric pressure fluctuation is within a certain range (±0.5 kPa in this example);

[0213] q) no misfire fault has occurred;

[0214] r) no GPF differential pressure sensor electrical fault has occurred;

[0215] s) no GPF temperature sensor fault has occurred;

[0216] t) no rationality fault of the periodic oscillation of the GPF differential pressure sensor has been detected in this vehicle driving cycle;

[0217] When the above conditions are met at the same time, it is determined that the self-learning working condition is present.

[0218] Further, according to t1, T GPFBrick , r GPFSootBegin The process of updating the self-learning correction coefficient r Adpat is as follows:

[0219] If t1>t Base ×f1(r GPFSootBegin , T GPFBrick(This indicates that if time t1 is too long, the cumulative carbon content coefficient calculated based on the GPF differential pressure sensor will be too large, indicating that the GPF differential pressure signal is overestimated.) Where t... Base The base time (7 seconds in this example, specifically the time when the GPF is functioning without a fault) is r GPFSootBegin =0.1, T GPFBrick = the time it takes for the accumulated carbon content to be reset to zero at 610℃), then r Adpat The update method is, r Adpat =r Adpat (z)-k1×f1(r GPFSootBegin ,T GPFBrick ); where k1 is the first gain coefficient, r Adpat (z) represents the self-learning correction coefficient stored in the last update;

[0220] Where f1(r) GPFSootBegin ,T GPFBrick The calibration results are as follows:

[0221]

[0222] If t1 <t Base ×f2(r GPFSootBegin ,T GPFBrick (This indicates that if time t1 is too short, the cumulative carbon content coefficient calculated based on the GPF differential pressure sensor will be too small, indicating that the GPF differential pressure signal will be underestimated); then r Adpat The update method is, r Adpat =r Adpat (z)-k2×f2(r GPFSootBegin ,T GPFBrick ); where k2 is the second gain coefficient (taken as 0.01 in this example);

[0223] Where f2(r) GPFSootBegin ,T GPFBrick The calibration results are as follows:

[0224]

[0225] If t Base ×f2(r GPFSootBegin ,T GPFBrick ) <t1<t Base ×f1(r GPFSootBegin ,T GPFBrick ), then r Adpat The number of times this condition is met remains unchanged; If the number of times exceeds a certain threshold (15 times in this example), then r Adpat =r Adpat (z)+k3; where k3 is the third gain coefficient (taken as 0.005 in this embodiment); The count updating mode is that when the condition t Base ×f2(r GPFSootBegin ,T GPFBrick ) < t1 < t Base ×f1(r GPFSootBegin ,T GPFBrick ) is met, one is added, and the count is increased by at most one in each driving cycle r Adpat is updated and is cleared.

[0226] Embodiment two:

[0227] The embodiment discloses a computer device, which comprises a memory, a processor and a computer program stored in the memory and executable on the processor, and the processor implements the steps of the rationality fault detection method of the periodic oscillation of the GPF differential pressure sensor in embodiment one when executing the computer program.

[0228] The above merely describes the embodiments of the present application, and does not limit the patent scope of the present application, and any equivalent structure or equivalent flow transformation, or direct or indirect application in other related technical fields, which is made by using the content of the specification and drawings of the present application, is also included in the patent protection scope of the present application.

Claims

1. A periodic oscillation plausibility fault detection method for a particulate filter (GPF) differential pressure sensor, characterized in that: The method comprises the following steps, obtaining the whole vehicle operating parameters, determining whether the current is in a steady state condition and meets the stability condition, if yes, then the subsequent steps are performed, if not, then the step is repeated; obtaining the GPF inlet pressure original value and the GPF outlet pressure original value, wherein the GPF inlet pressure original value and the GPF outlet pressure original value are measured by the particulate filter differential pressure sensor; performing first-order low-pass filtering on the GPF inlet pressure original value and the GPF outlet pressure original value respectively to obtain the GPF inlet pressure filtered value and the GPF outlet pressure filtered value; obtaining the interval time length between the extreme values of the GPF inlet pressure filtered value at different time and the interval time length between the extreme values of the GPF outlet pressure filtered value at different time according to the GPF inlet pressure filtered value at different time and the GPF outlet pressure filtered value at different time; determining whether the particulate filter differential pressure sensor has a reasonable periodic oscillation failure according to the interval time length between the extreme values of the GPF inlet pressure filtered value at different time and the interval time length between the extreme values of the GPF outlet pressure filtered value at different time.

2. The periodic oscillation rationality fault detection method of the particulate filter GPF differential pressure sensor according to claim 1, characterized in that: The steady state condition determination condition is as follows, the engine is in an operating state; the engine speed is within a certain range, and after the detection of the reasonable periodic oscillation failure of the GPF differential pressure sensor, the engine speed fluctuation is within a certain range; the intake density of fresh air entering the cylinder is within a certain range, and after the detection of the reasonable periodic oscillation failure of the GPF differential pressure sensor, the intake density fluctuation of fresh air entering the cylinder is within a certain range; the target air-fuel ratio fluctuation is within a certain range; the difference fluctuation between the target air-fuel ratio and the actual air-fuel ratio is within a certain range; the actual air-fuel ratio fluctuation is within a certain range; the GPF body temperature fluctuation is within a certain range; the engine water temperature is within a certain range, and after the detection of the reasonable periodic oscillation failure of the GPF differential pressure sensor, the engine water temperature fluctuation is within a certain range; the intake temperature is within a certain range, and after the detection of the reasonable periodic oscillation failure of the GPF differential pressure sensor, the intake temperature fluctuation is within a certain range; the ignition angle efficiency fluctuation is within a certain range; no knock and no pre-ignition occur; the engine does not have oil break; the pre-catalyst oxygen sensor and the post-catalyst oxygen sensor have completed heating activation; the atmospheric pressure fluctuation is within a certain range; no misfire failure occurs; no GPF differential pressure sensor electrical failure occurs; no GPF temperature sensor failure occurs; no reasonable periodic oscillation failure of the GPF differential pressure sensor is detected in the current vehicle driving cycle; when the above conditions are met at the same time, it is determined that the steady state condition is met.

3. The periodic oscillation rationality fault detection method of a particulate filter GPF differential pressure sensor according to claim 1, characterized by: The stability condition is that the time continuously in the steady state condition exceeds a certain time length.

4. The periodic oscillation rationality fault detection method of a particulate filter GPF differential pressure sensor according to claim 1, characterized by: The GPF inlet pressure filtered value and the GPF outlet pressure filtered value are obtained as follows, wherein is the GPF inlet pressure raw value of the Nth sampling period, is the GPF inlet pressure filtered value of the Nth sampling period, is the GPF inlet pressure filtered value of the (N-1)th sampling period; is the GPF outlet pressure raw value of the Nth sampling period, is the GPF outlet pressure filtered value of the Nth sampling period, is the GPF outlet pressure filtered value of the (N-1)th sampling period; N is a positive integer; the sampling period interval is ; is the GPF inlet pressure filtered coefficient, is the GPF outlet pressure filtered coefficient, and satisfies In the above formulae, is the number of engine cylinders, is the engine speed, and are each calibrated based on the engine speed.

5. The periodic oscillation rationality fault detection method of the particulate filter GPF differential pressure sensor according to claim 1, characterized in that: The process of judging whether the GPF differential pressure sensor has a periodic oscillation rationality fault according to the interval length between the extreme values of the GPF inlet pressure filtering values at different times and the interval length between the extreme values of the GPF outlet pressure filtering values at different times is as follows: The time interval between the maximum value of the GPF inlet pressure filtered value of a sampling period and the maximum value of the GPF inlet pressure filtered value of the last sampling period of the sampling period is recorded as the GPF inlet pressure filtered value adjacent maximum value time interval of the sampling period The time interval between the minimum value of the GPF inlet pressure filtered value of a sampling period and the minimum value of the GPF inlet pressure filtered value of the last sampling period of the sampling period is recorded as the GPF inlet pressure filtered value adjacent minimum value time interval of the sampling period The time interval between the maximum value of the GPF inlet pressure filtered value of a sampling period and the maximum value of the GPF inlet pressure filtered value of the last sampling period of the sampling period is recorded as the GPF inlet pressure filtered value adjacent maximum value time interval of the sampling period According to the adjacent maximum time interval of the GPF inlet pressure filtering value of different sampling periods , the adjacent minimum time interval of the GPF inlet pressure filtering value , the adjacent maximum time interval average of the GPF inlet pressure filtering value is calculated respectively , the adjacent minimum time interval average of the GPF inlet pressure filtering value ; If the following condition is met, Then the reasonability of the periodic oscillation of the GPF differential pressure sensor is judged, wherein is a preset value; The time interval between the maximum value of the GPF outlet pressure filtered value of a sampling period and the maximum value of the GPF outlet pressure filtered value of the last sampling period of the sampling period is recorded as the GPF outlet pressure filtered value adjacent maximum value time interval of the sampling period The time interval between the minimum value of the GPF outlet pressure filtered value of a sampling period and the minimum value of the GPF outlet pressure filtered value of the last sampling period of the sampling period is recorded as the GPF outlet pressure filtered value adjacent minimum value time interval of the sampling period ​ According to the adjacent maximum time interval of the GPF outlet pressure filtered value of different sampling periods , the adjacent minimum time interval of the GPF outlet pressure filtered value , the adjacent maximum time interval of the GPF outlet pressure filtered value is calculated respectively , the adjacent minimum time interval of the GPF outlet pressure filtered value ; If the following condition is met, It is judged that the GPF differential pressure sensor has a periodic oscillation rationality fault. According to the average value of the time interval of adjacent maximum values of the GPF inlet pressure filtering value , the time interval of adjacent minimum values of the GPF inlet pressure filtering value , the oscillation period of the GPF inlet pressure is obtained , specifically; According to the average value of the time interval of adjacent maximum values of the GPF outlet pressure filtered value According to the time interval of adjacent minimum values of the GPF outlet pressure filtered value Obtain the GPF outlet pressure oscillation period Specifically; If the following condition is met; Then, it is judged that the GPF pressure difference sensor has a periodic oscillation rationality fault, wherein The GPF body temperature And the cumulative carbon content coefficient are determined together, the cumulative carbon content coefficient is obtained according to the current actual carbon content m_Soot of the GPF and the upper limit value m_SootCapacity of the GPF carbon loading, specifically ; The initial value of the self-learning correction coefficient is 0 and is updated according to self-learning, and is saved after the vehicle is powered off.

6. The periodic oscillation rationality fault detection method of a particulate filter GPF differential pressure sensor according to claim 5, characterized in that: GPF inlet pressure filtered value adjacent maximum time interval average GPF inlet pressure filtered value adjacent minimum time interval average The acquisition process is as follows: If the time interval between adjacent maxima of the GPF inlet pressure filter value in the current sampling period is... Less than a preset value And the current sampling period Other sampling periods The time difference is less than a preset value. Then the current sampling period will be Remove it so that it does not participate. The calculation; where Related to engine speed n, For other sampling periods A certain multiple of the average value; If the number of times that the event "the time interval between the adjacent maximum values of the GPF inlet pressure filtering value in the current sampling period is less than the preset value" occurs accumulates more than the preset number of times during the continuous sampling of the GPF outlet / inlet pressure, it is determined that the GPF pressure difference sensor has a reasonable fault of periodic oscillation. ​​​ If the time interval between adjacent maxima of the GPF inlet pressure filter value in the current sampling period is... Greater than a preset value And the current sampling period Other sampling periods The time difference is greater than a preset value Then the current sampling period will be Remove it so that it does not participate. The calculation; where Related to engine speed n, For other sampling periods A certain multiple of the average value; If the number of times that the event "the time interval between the adjacent maximum values of the GPF inlet pressure filtering value in the current sampling period is greater than the preset value" occurs in the process of continuously sampling the GPF outlet / inlet pressure is accumulated to be greater than the preset number of times , it is determined that the GPF pressure difference sensor has a reasonable fault of periodic oscillation. ​​ The remaining sampling periods after the elimination are Taking the average, we get ; If the time interval between adjacent minimum values ​​of the GPF inlet pressure filter value in the current sampling period is... Less than a preset value And the current sampling period Other sampling periods The time difference is less than a preset value. Then the current sampling period will be Remove it so that it does not participate. The calculation; where Related to engine speed n, For other sampling periods A certain multiple of the average value; If the number of times that the event "the adjacent minimum value time interval of the GPF inlet pressure filtering value of the current sampling period is less than the preset value" occurs in the process of continuous sampling of the GPF outlet / inlet pressure is accumulated to be more than the preset number of times , it is determined that the GPF pressure difference sensor has a reasonable fault of periodic oscillation. ​​ If the time interval between adjacent minimum values ​​of the GPF inlet pressure filter value in the current sampling period is... Greater than a preset value And the current sampling period Other sampling periods The time difference is greater than a preset value Then the current sampling period will be Remove it so that it does not participate. The calculation; where Related to engine speed n, For other sampling periods A certain multiple of the average value; If the number of times that the event "the adjacent minimum value time interval of the GPF inlet pressure filtering value of the current sampling period is greater than the preset value" occurs in the process of continuous sampling of the GPF outlet / inlet pressure is accumulated to be greater than the preset number of times , it is determined that the GPF pressure difference sensor has a reasonable fault of periodic oscillation. ​​ The remaining sampling periods after the elimination are Taking the average, we get .

7. The periodic oscillation rationality fault detection method of the particulate filter GPF differential pressure sensor according to claim 5, characterized in that: GPF outlet pressure filtered value adjacent maximum time interval average value GPF outlet pressure filtered value adjacent minimum time interval average value The acquisition process is as follows: If the time interval between adjacent maxima of the GPF outlet pressure filter value in the current sampling period is... Less than a preset value And the current sampling period Other sampling periods The time difference is less than a preset value. Then the current sampling period will be Remove it so that it does not participate. The calculation; where Related to engine speed n, For other sampling periods A certain multiple of the average value; If, during continuous sampling of GPF inlet / outlet pressure, the event "Time interval between adjacent maxima of the GPF outlet pressure filter value in the current sampling period" occurs... Less than the preset value "The cumulative number of occurrences exceeds the preset number" If so, it can be determined that the GPF differential pressure sensor has a reasonable fault of periodic oscillation; If the time interval between adjacent maxima of the GPF outlet pressure filter value in the current sampling period is... Greater than a preset value And the current sampling period Other sampling periods The time difference is greater than a preset value Then the current sampling period will be Remove it so that it does not participate. The calculation; where Related to engine speed n, For other sampling periods A certain multiple of the average value; If the number of times that the event "the time interval between the adjacent maximum values of the GPF outlet pressure filtering value in the current sampling period is greater than the preset value" occurs in the process of continuously sampling the GPF inlet / outlet pressure is accumulated to be greater than the preset number of times , it is determined that the GPF pressure difference sensor has a reasonable fault of periodic oscillation. ​​ The remaining sampling periods after the elimination are Taking the average, we get ; If the time interval between adjacent minimum values ​​of the GPF outlet pressure filter value in the current sampling period is... Less than a preset value And the current sampling period Other sampling periods The time difference is less than a preset value. Then the current sampling period will be Remove it so that it does not participate. The calculation; where Related to engine speed n, For other sampling periods A certain multiple of the average value; If the number of times that the event "the adjacent minimum value time interval of the GPF outlet pressure filtering value of the current sampling period is less than the preset value" occurs in the process of continuous sampling of the GPF inlet / outlet pressure is accumulated to be more than the preset number of times , it is determined that the GPF pressure difference sensor has a reasonable fault of periodic oscillation. ​​ If the time interval between adjacent minimum values ​​of the GPF outlet pressure filter value in the current sampling period is... Greater than a preset value And the current sampling period Other sampling periods The time difference is greater than a preset value Then the current sampling period will be Remove it so that it does not participate. The calculation; where Related to engine speed n, For other sampling periods A certain multiple of the average value; If the number of times that the event "the adjacent minimum value time interval of the GPF inlet pressure filtering value of the current sampling period is greater than the preset value" occurs in the process of continuous sampling of the GPF outlet / inlet pressure is accumulated to be greater than the preset number of times , it is determined that the GPF pressure difference sensor has a reasonable fault of periodic oscillation. ​​ The remaining sampling periods after the elimination are Taking the average, we get .

8. The periodic oscillation rationality fault detection method of the particulate filter GPF differential pressure sensor according to claim 5, characterized in that: Self-learning correction coefficient The self-learning update process is as follows; determining whether the current is in the self-learning working condition, if yes, reading the cumulative carbon amount coefficient at the initial time in the self-learning working condition , and obtaining the value of the cumulative carbon amount coefficient at the time when the value of the cumulative carbon amount coefficient becomes 0 ; According to , , the self-learning correction coefficient is updated.

9. The periodic oscillation rationality fault detection method of a particulate filter GPF differential pressure sensor according to claim 8, characterized in that: The self-learning working condition judgment condition is as follows, a) The engine is in a running state; b) The engine speed fluctuation is within a certain range; c) The vehicle speed exceeds a certain value; d) a carbon build-up coefficient not more than a certain value; e) The GPF body temperature is not lower than a certain value; f) The intake density fluctuation of fresh air entering the cylinder is within a certain range; g) The target air-fuel ratio fluctuation is within a certain range; h) The difference between the target air-fuel ratio and the actual air-fuel ratio fluctuation is within a certain range; i) The actual air-fuel ratio fluctuation is within a certain range; j) The engine water temperature is within a certain range, and the engine water temperature fluctuation is within a certain range after the periodic oscillation rationality fault detection of the GPF differential pressure sensor; k) The intake temperature is within a certain range, and the intake temperature fluctuation is within a certain range after the periodic oscillation rationality fault detection of the GPF differential pressure sensor; l) The ignition angle efficiency fluctuation is within a certain range; m) No knock and no pre-ignition occurs; n) The GPF body temperature fluctuation is within a certain range; o) The catalyst before oxygen sensor and the catalyst after oxygen sensor have completed the heating activation; p) The atmospheric pressure fluctuation is within a certain range; q) No misfire fault occurs; r) No GPF differential pressure sensor electrical fault occurs; s) No GPF temperature sensor fault occurs; t) No periodic oscillation rationality fault of the GPF differential pressure sensor is detected in this vehicle driving cycle; When the above conditions are met at the same time, it is judged that the self-learning working condition is met.

10. The periodic oscillation rationality fault detection method of a particulate filter GPF differential pressure sensor according to claim 8, characterized by: According to , , The process of updating the self-learning correction coefficient is as follows: If wherein is the base time, According to , calibration; then The update mode is ; wherein k1 is the first gain coefficient, is the last updated stored self-learning correction coefficient; If wherein According to , calibration; then The update mode is ; wherein k2 is a second gain coefficient; like ,but The number of times this condition is met remains unchanged; If it exceeds a certain number of times, then Where k3 is the third gain coefficient; The count update method is as follows: when the condition is met... The condition is incremented by one, and in each driving cycle... At most one more, when After the update Reset to zero.

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