A method for improving failure determination of intake pressure control

Abstract

The application discloses a kind of failure judging methods for improving intake pressure control, comprising: using first method, second method respectively to throttle inlet pressure signal is checked, whether throttle inlet pressure signal appears failure is judged;First method is: according to the estimated value and sampling number of the filter engine speed, throttle inlet pressure signal obtained judges whether throttle inlet pressure signal appears failure;Second method is: when throttle inlet pressure stable condition judging condition is satisfied, the average value of throttle inlet pressure in preset time and the average value of throttle outlet pressure are obtained, and whether throttle inlet pressure signal appears failure is judged in combination with self-learning correction coefficient.The method provided by the application can check the rationality of the pressure signal of the pressure sensor before the throttle.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of engine control, and particularly relates to a failure judgment method for improving intake pressure control. BACKGROUND

[0002] Intake pressure is an important parameter of intake system control. Research shows that the control accuracy and responsiveness of intake pressure will affect the vehicle power, drivability and fuel economy. The maximum output power of the engine is proportional to the intake pressure, and the fuel consumption rate decreases with the increase of the intake pressure. When the intake pressure appears abnormal fluctuations (such as abnormality of intake system components, such as intake manifold air leakage, deterioration of throttle performance, deterioration of supercharger performance, abnormality of intake system sensors, etc.), if the post-fluctuation improvement control is not performed in time, it will cause the intake amount control, fuel injection control and torque performance.

[0003] The patent with the application number 202110982953.2 discloses "a throttle flow calculation method, device, equipment and readable storage medium", which estimates the EGR method flow by using the pressure before the throttle (inlet pressure) and the pressure after the throttle (outlet pressure), but does not propose a failure judgment method for improving intake pressure control.

[0004] The patent with the application number 202110518171.3 discloses "a measurement method and device of EGR mass flow and exhaust gas treatment system", which estimates the EGR method flow by using the pressure before the throttle (inlet pressure) and the pressure after the throttle (outlet pressure), but does not propose a failure judgment method for improving intake pressure control. SUMMARY

[0005] The present application solves the technical problem of the prior art and provides a failure judgment method for improving intake pressure control, which can check the rationality of the pressure signal of the pressure sensor before the throttle.

[0006] To achieve the above-mentioned purpose, according to one aspect of the present application, a failure judgment method for improving intake pressure control is provided, comprising:

[0007] The first method and the second method are used to check the throttle inlet pressure signal respectively;

[0008] According to the results of the first method and the second method, it is judged whether the throttle inlet pressure signal appears failure;

[0009] The first method is that the engine speed is filtered to obtain a filtered engine speed.

[0010] reading the throttle inlet pressure signal for a plurality of times in succession, and estimating the throttle inlet pressure signal of the next sampling period from the throttle inlet pressure signal of the current time;

[0011] determining the sampling times for throttle inlet pressure signal checking;

[0012] judging whether the throttle inlet pressure signal is faulty according to the filtered engine speed, the estimated value of the throttle inlet pressure signal and the sampling times;

[0013] the second method is: when the judgment condition of the stable working condition of the throttle inlet pressure is met, obtaining the average value of the throttle inlet pressure and the average value of the throttle outlet pressure within a preset time;

[0014] judging whether the throttle inlet pressure signal is faulty according to the average value of the throttle inlet pressure, the average value of the throttle outlet pressure and the self-learning correction coefficient.

[0015] In the above scheme, in the first method: the calculation method of the filtered engine speed n Filt is as follows: the filtered engine speed n Filt (m) of the current sampling period and the filtered engine speed n Filt (m+1) of the next sampling period and the original real-time engine speed n Raw read by the sensor are related as follows:

[0016] n Filt (m+1)=k×n Raw +(1-k)×n Filt (m);

[0017] wherein m=0, 1, 2…, and in particular, n Filt (0) is 0; k is the filtering coefficient.

[0018] In the above scheme, in the first method: the method for estimating the estimated value of the throttle inlet pressure signal of the next sampling period from the throttle inlet pressure signal of the current time is as follows: the latest continuous N (N is not less than 7) throttle inlet pressure signals are read in real time, and an array [p ThrBfAct (0), p ThrBfAct (1), p ThrBfAct (N-1)…] is formed, wherein p ThrBfAct (0) is the throttle inlet pressure signal read in the current sampling period, p ThrBfAct (N-1) is the throttle inlet pressure signal read in the previous N-1 sampling periods, and the throttle inlet pressure signal p ThrBfAct of the previous k sampling periods is obtained in the same way.(k), k = 0, 1, 2, …, N-1; the estimated value p of the throttle inlet pressure signal estimated in the previous k-1 sampling periods ThrBfAct (k-1)' = p

[0019]

[0020] wherein the estimated value p of the next throttle inlet pressure signal when k = 0 ThrBfAct (k+1)' = p ThrBfAct (1)' = 0 (kPa / s); the rate of change of the throttle inlet pressure signal in the previous k sampling period is: wherein Δp when k = 0 ThrBfAct (k) = Δp ThrBfAct (0) = 0 (kPa / s), p ThrBfAct (k+1)' = p ThrBfAct (1)' = 0 (kPa / s); Δt is the sampling period; t c is the pressure estimation filtering time period.

[0021] In the above scheme, in the first method: the method for determining the sampling number V for throttle inlet pressure signal checking is: according to the filtered engine speed n Filt and the original real-time engine speed n Raw , the value of is calculated; wherein when the value is 0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.28, 0.3, 0.32, the sampling number V corresponds to the values 1, 1, 2, 2, 3, 4, 4, 5, 6, and when the value of is located between any two adjacent numbers in 0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.28, 0.3, 0.32, the sampling number V takes the value of the sampling number V corresponding to the larger number of the two adjacent numbers; wherein the and the sampling number V are compared in the following table:

[0022]

[0023] The larger the value of the filtered engine speed n

[0024] In the above scheme, the method for judging whether the throttle inlet pressure signal is faulty according to the filtered engine speed, the estimated value of the throttle inlet pressure signal, and the sampling number is:

[0025] When the throttle inlet pressure judgment condition is met, obtain the estimated value p of the throttle inlet pressure signal for V consecutive sampling periods of the current period. ThrBfAct (V-1)' and the actual value p of the throttle inlet pressure signal read by the sensor ThrBfAct (V-1);

[0026] When V = 1, if |p ThrBfAct (0)'-p ThrBfAct (0) If the value is greater than the preset value C1, then the throttle inlet pressure signal is judged to have a preliminary fault; otherwise, the throttle inlet pressure signal is judged not to have a preliminary fault. The preset value C1 is 5 × (1 + r Lrn ), r Lrn This is the self-learning correction coefficient for the preset value C1, which has a default value of 0 and can be saved after the vehicle is powered off.

[0027] When V = 2, if |p ThrBfAct (0)'-p ThrBfAct (0)|、|p ThrBfAct (1)'-p ThrBfAct (1) If all values ​​are greater than the preset value C1, it is determined that the throttle inlet pressure signal has a preliminary fault; otherwise, it is determined that the throttle inlet pressure signal has not a preliminary fault.

[0028] When V = 3, if |p ThrBfAct (0)'-p ThrBfAct (0)|、|p ThrBfAct (1)'-p ThrBfAct (1)|、|p ThrBfAct (2)'-p ThrBfAct (2) If all values ​​are greater than the preset value C1, it is determined that the throttle inlet pressure signal has a preliminary fault; otherwise, it is determined that the throttle inlet pressure signal has not a preliminary fault.

[0029] When V = 4, if |p ThrBfAct (0)'-p ThrBfAct (0)|、|p ThrBfAct (1)'-p ThrBfAct (1)|、|p ThrBfAct (2)'-p ThrBfAct (2) |p ThrBfAct (3)'-p ThrBfAct (3) If all values ​​are greater than the preset value C1, it is determined that the throttle inlet pressure signal has a preliminary fault; otherwise, it is determined that the throttle inlet pressure signal has not a preliminary fault.

[0030] When V = 5, if |p ThrBfAct (0)'-p ThrBfAct (0)|、|p ThrBfAct (1)'-pThrBfAct (1)|、|p ThrBfAct (2)'-p ThrBfAct (2) |p ThrBfAct (3)'-p ThrBfAct (3)|、|p ThrBfAct (4)'-p ThrBfAct (4) If all values ​​are greater than the preset value C1, it is determined that the throttle inlet pressure signal has a preliminary fault; otherwise, it is determined that the throttle inlet pressure signal has not a preliminary fault.

[0031] When V = 6, if |p ThrBfAct (0)'-p ThrBfAct (0)|、|p ThrBfAct (1)'-p ThrBfAct (1)|、|p ThrBfAct (2)'-p ThrBfAct (2)|、|p ThrBfAct (3)'-p ThrBfAct (3)|、|p ThrBfAct (4)'-p ThrBfAct (4)|、|p ThrBfAct (5)'-p ThrBfAct (5) If all values ​​are greater than the preset value C1, it is determined that the throttle inlet pressure signal has a preliminary fault; otherwise, it is determined that the throttle inlet pressure signal has not a preliminary fault.

[0032] The self-learning correction coefficient r of the preset value C1 Lrn The update method is as follows: Record the effective number of times (CNT1) the throttle inlet pressure signal did not show a preliminary fault and the invalid number of times (CNT2) the throttle inlet pressure signal showed a preliminary fault under different sampling numbers (V). CNT1 and CNT2 are updated at most once per vehicle driving cycle. If CNT1 ≥ 160 and CNT2 ≤ 10, then r... Lrn =r Lrn (z)-0.005; if CNT1≤10 and CNT2≥160, then r Lrn =r Lrn (z)+0.012; otherwise, r Lrn =r Lrn (z); where r L rn(z) is the self-learning correction coefficient of the previously updated preset value C1;

[0033] When CNT1 + CNT2 > 200, CNT1 = 180, and If the throttle inlet pressure signal is faulty, it is determined that the throttle inlet pressure signal is not faulty; and when the throttle inlet pressure signal is determined to be faulty, CNT1 and CNT2 are cleared to zero, and the counting will start again when the condition is met again.

[0034] In the above scheme, the throttle inlet pressure judgment condition is:

[0035] (1) The actual intake air density of the engine entering the cylinder does not fluctuate beyond the preset value; excessive fluctuation leads to reduced detection accuracy.

[0036] (2) Throttle opening fluctuation does not exceed the preset value; excessive fluctuation leads to reduced detection accuracy.

[0037] (3) The engine running time in this engine driving cycle exceeds the preset time.

[0038] In the above scheme, the second method specifically refers to:

[0039] When the throttle inlet pressure stability condition is met, the average throttle inlet pressure within a preset time t3 is obtained. Average throttle outlet pressure

[0040] like If the throttle inlet pressure signal is faulty, it is determined that the throttle inlet pressure signal is not faulty; otherwise, it is determined that the throttle inlet pressure signal is not faulty.

[0041] In the above scheme, r Adpt This is the self-learning correction factor, with a default value of 0, which can be saved when the vehicle is powered off.

[0042] In the above scheme, the self-learning correction coefficient r Adpt The method for obtaining the value is as follows: Record the number of times (CNT3) the throttle inlet pressure stabilization condition judgment condition is met, and record the number of times (CNT3) the throttle inlet pressure stabilization condition judgment condition is met. The number of times CNT4 is recorded, and the condition for judging stable throttle inlet pressure is satisfied is recorded. The number of times CNT5 is updated, and CNT3, CNT4, and CNT5 are updated at most once in each driving cycle of the vehicle;

[0043] If CNT3≥200, CNT4≥160, and CNT5≤10, then r Adpt =r Adpt (z)-0.01;

[0044] If CNT3 ≥ 200, CNT4 ≤ 10, and CNT5 ≥ 130, then r Adpt =r Adpt (z)+0.015;

[0045] Other cases, r Adpt = r Adpt (z);

[0046] Wherein r Adpt (z) is the last updated self-learning correction coefficient; when CNT3≥200, then the self-learning correction coefficient r Adpt After updating, CNT3, CNT4 and CNT5 are reset to 0 until the next condition is met to start accumulating the count again.

[0047] In the above scheme, the throttle inlet pressure stable working condition judgment condition is:

[0048] (1) the engine is in operation;

[0049] (2) the target intake amount is stable;

[0050] (3) the actual intake pressure at the throttle outlet is stable;

[0051] (4) the engine speed fluctuation does not exceed the preset range;

[0052] (5) the boost actuator opening degree is equal to its full opening degree;

[0053] (6) the throttle opening degree is greater than the preset value;

[0054] (7) the throttle outlet pressure signal has not detected a fault;

[0055] (8) the product of the engine short-term fuel correction and the long-term fuel correction is within the preset range and exceeds the preset time t2.

[0056] In the above scheme, the method for judging the stability of the target intake amount is:

[0057] rho DesFilter (N) = K Rho × [rho DesRaw (N) - rho DesFilter (N-1)] + rho DesFilter (N-1); Wherein, rho DesRaw is the target intake amount, rho DesRaw (N) is the target intake amount of the Nth sampling period, rho DesFilter is the first-order low-pass filtered target intake amount, rho DesFilter (N) is the filtered target intake amount of the Nth sampling period, rho DesFilter (N-1) is the filtered target intake amount of the N-1th sampling period, N = 1, 2, 3…, rho DesFilter(0) is equal to the target intake amount rho at the 0th sampling period DesRaw (0); sampling period interval At; K Rho is a coefficient, and is a preset value: wherein n is the engine speed, k Rho is an air amount filtering coefficient, and is a preset value;

[0058] When |rho DesRaw (N)-rho DesFilter (N)|<min[rho DesRaw (N), rho DesFilter (N)]x r RhoLim and the condition is continuously met for T Rho time, it is indicated that the target intake amount is in a stable state. Wherein r RhoLim is a preset value, and T Rho is a preset value.

[0059] In the above scheme, the method for judging that the actual intake pressure at the throttle valve outlet is stable is:

[0060] p ManFilter (N)=K Man x[p Man (N)-p ManFilter (N-1)]+p ManFilter (N-1); wherein p Man is the intake pressure at the throttle valve outlet, p Man (N) is the intake pressure at the throttle valve outlet at the Nth sampling period, p ManFilter is the first-order low-pass filtered intake pressure at the throttle valve outlet, p ManFilter (N) is the filtered intake pressure at the throttle valve outlet at the Nth sampling period, p ManFilter (N-1) is the filtered intake pressure at the throttle valve outlet at the (N-1)th sampling period, N=1, 2, 3…, and p ManFilter (0) is equal to the intake pressure at the throttle valve outlet at the 0th sampling period p Man (0); the sampling period interval At is a preset value; and K Man is a coefficient, and is a preset value: wherein n is the engine speed, k Man is a filtering coefficient of the intake pressure at the throttle valve outlet, and is a preset value;

[0061] When |p Man (N)-p ManFilter (N)|<min[p Man (N), p ManFilter (N)]x r ManLim and the condition is continuously met for T Man time, it is indicated that the intake pressure is in a stable state; wherein rManLim is a preset value, T Man is a preset value.

[0062] In the above scheme, the method for judging whether the throttle inlet pressure signal is faulty according to the results of the first method and the second method is:

[0063] If the second method judges that the throttle inlet pressure signal is faulty and the first method judges that the throttle inlet pressure signal is not faulty during the current driving cycle, it is finally judged that the throttle inlet pressure signal is not faulty, and the self-learning correction coefficient r of the preset value C1 is updated Lrn = r Lrn (z) + 0.03, the self-learning correction coefficient r is updated Adpt = r Adpt (z) - 0.005.

[0064] If the second method judges that the throttle inlet pressure signal is not faulty and the first method judges that the throttle inlet pressure signal is faulty during the current driving cycle, it is finally judged that the throttle inlet pressure signal is faulty, and the self-learning correction coefficient r of the preset value C1 is updated Lrn = r Lrn (z) - 0.04, the self-learning correction coefficient r is updated Adpt = r Adpt (z) - 0.05.

[0065] If the second method judges that the throttle inlet pressure signal is not faulty and the first method judges that the throttle inlet pressure signal is not faulty during the current driving cycle, it is finally judged that the throttle inlet pressure signal is not faulty, and the self-learning correction coefficient r of the preset value C1 is updated Adpt = r Adpt (z), the self-learning correction coefficient r is updated Lrn = r Lrn (z).

[0066] If the second method judges that the throttle inlet pressure signal is faulty and the first method judges that the throttle inlet pressure signal is faulty during the current driving cycle, it is finally judged that the throttle inlet pressure signal is faulty, and the self-learning correction coefficient r of the preset value C1 is updated Adpt = r Adpt (z), the self-learning correction coefficient r is updated Lrn = r Lrn (z).

[0067] wherein r Adpt (z) is the self-learning correction coefficient updated last time; wherein r Lrn(z) is a self-learning correction coefficient of the preset value C1 of the last update.

[0068] r is updated only based on the two methods as above Adpt , r Lrn The reason is that the first method and the second method are both sampled and estimated during engine operation, and as the engine life cycle progresses, more components may age, and the data offset of their aging is greater than when the engine is stopped. Only consider static data and the performance of the throttle when the engine is stopped. Based on this, only consider the data offset of the first method and the second method; but the second method is also running in a steady state of the engine, and its detection accuracy is also relatively high, so its r Adpt update speed is not as fast as r Lrn .

[0069] Overall, compared with the prior art, the above technical solutions conceived by the present application can achieve the following beneficial effects:

[0070] The present application provides a kind of to improve the failure judgment method of intake pressure control, which checks whether the intake pressure is reasonable by multiple methods, and accurately carries out pressure signal degradation monitoring, while constantly updating parameters in the process of pressure signal degradation monitoring, improve the subsequent pressure signal degradation monitoring identification precision. BRIEF DESCRIPTION OF DRAWINGS

[0071] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are for purposes of illustration only and are not intended to limit the present application thereto. Moreover, the use of the same reference numerals in different figures indicates same or similar components. In the drawings:

[0072] Figure 1 It is a schematic diagram of the intake system of the exhaust turbocharged engine in the embodiment of the present application.

[0073] Figure 2 It is a flowchart of a kind of failure judgment method for improving intake pressure control in the embodiment of the present application. DETAILED DESCRIPTION

[0074] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0075] It should be understood that the sequence number of each step in the embodiment does not imply 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.

[0076] Example 1

[0077] The main components of the intake system of the turbocharged exhaust engine upon which this invention is based include: atmospheric pressure sensor, turbocharger, electronic wastegate, intercooler, pre-throttle temperature and pressure sensor, throttle body, post-throttle intake temperature and pressure sensor, carbon canister solenoid valve, EGR, VVT system, etc. Figure 1 As shown in the diagram. The atmospheric pressure sensor reads atmospheric pressure and is installed on the PCB board of the ECU controller. The turbocharger includes the turbocharger body and a wastegate valve; the boost pressure is controlled by adjusting the opening of the wastegate valve. The electronic pressure relief valve opens to prevent airflow from oscillating within the turbocharger compressor when the engine requests reduced torque, thus improving turbocharger surge, engine life, and NVH (noise, vibration, and harshness). The throttle body temperature and pressure sensor reads the temperature and pressure of the boosted gas before the throttle body. The intercooler is a mechanical component, uncontrolled, located between the turbocharger compressor and the throttle body, cooling the boosted gas. The throttle body intake air temperature and pressure sensor reads the temperature and pressure of the boosted gas before the throttle body. The carbon canister solenoid valve introduces fuel vapor into combustion and prevents it from evaporating into the atmosphere.

[0078] EGR, or Exhaust Gas Recirculation, returns a portion of the exhaust gas from the engine to the intake manifold, where it mixes with fresh air and re-enters the cylinders. VVT is used to adjust the intake (exhaust) volume, valve opening and closing time, and angle to regulate the amount of air entering the cylinders. The throttle inlet pressure signal verification in this invention verifies the validity of the pressure signal from the throttle inlet pressure sensor.

[0079] This application provides a method for improving intake pressure control failure judgment according to one aspect of the present invention, see reference. Figure 2 ,include:

[0080] S1, use the first method and the second method respectively to check the throttle inlet pressure signal.

[0081] Specifically, in this embodiment, the first method is to filter the engine speed to obtain the filtered engine speed;

[0082] Read several consecutive throttle inlet pressure signals, and estimate the value of the throttle inlet pressure signal in the next sampling cycle based on a certain throttle inlet pressure signal;

[0083] Determine the number of samples to be used for throttle inlet pressure signal verification;

[0084] According to the filtered engine speed, the estimated value of the throttle inlet pressure signal and the sampling number, it is judged whether the throttle inlet pressure signal is in failure.

[0085] Specifically, in the first method:

[0086] The filtered engine speed n Filt is obtained The calculation method is that the filtered engine speed n Filt (m+1) of the next sampling period and the original real-time engine speed n Filt (m) of the current sampling period and the original real-time engine speed n Raw read by the sensor establish the following relationship:

[0087] n Filt (m+1) = k x n Raw +(1-k) x n Filt (m);

[0088] Wherein m = 0, 1, 2…, and specifically n Filt (0) is 0; k is the filtering coefficient, and in the present example, k is 0.2.

[0089] The throttle inlet pressure signal is read for several times, and the method for estimating the estimated value of the throttle inlet pressure signal of the next sampling period through the throttle inlet pressure signal is that the latest continuous 9 throttle inlet pressure signals are read in real time, and an array [p ThrBfAct (0), p ThrBfAct (1), p ThrBfAct (N-1)…] is formed, wherein p ThrBfAct (0) is the throttle inlet pressure signal read in the current sampling period, p ThrBfAct (N-1) is the throttle inlet pressure signal read in the previous N-1 sampling periods, and the throttle inlet pressure signal p ThrBfAct (k) of the previous k sampling periods is obtained in the same way, k = 0, 1, 2…, N-1; and the estimated value p ThrBfAct (k-1)' of the throttle inlet pressure signal of the previous k-1 sampling periods is estimated:

[0090]

[0091] Wherein when k = 0, the estimated value p ThrBfAct (k+1)' of the next throttle inlet pressure signal is p ThrBfAct (1)' = 0 (kPa / s); and the change rate of the throttle inlet pressure signal of the previous k sampling periods is: Wherein when k = 0, Δp ThrBfAct (k) = Δp ThrBfAct (0) = 0 (kPa / s), pThrBfAct (k+1)'=p ThrBfAct (1)'=0(kPa / s); Δt is the sampling period, which is 10ms in this example; t c The pressure prediction filtering time period is set to 30ms in this example;

[0092] The method for determining the number of samplings V used for throttle inlet pressure signal verification is as follows: based on the filtered engine speed n Filt And the original real-time engine speed n Raw calculate The value of; among which When the value is 0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.28, 0.3, 0.32, the sampling number V corresponds to the value 1, 1, 2, 2, 3, 4, 4, 5, 6. When the value is between two consecutive numbers in the ranges of 0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.28, 0.3, and 0.32, the sampling count V is taken as the value corresponding to the larger of the two consecutive numbers; where... The table showing the relationship between the sampling number V and the actual sampling number is as follows:

[0093]

[0094] The larger the value, the greater the engine speed fluctuation, and the more pressure signals need to be sampled to determine whether the throttle inlet pressure signal is faulty.

[0095] The method for determining whether there is a fault in the throttle inlet pressure signal based on the estimated value and sampling number of the filtered engine speed and throttle inlet pressure signal is as follows:

[0096] When the throttle inlet pressure judgment condition is met, obtain the estimated value p of the throttle inlet pressure signal for V consecutive sampling periods of the current period. ThrBfAct (V-1)' and the actual value p of the throttle inlet pressure signal read by the sensor ThrBfAct (V-1);

[0097] In this embodiment, the throttle inlet pressure determination condition is:

[0098] (1) The actual intake air density fluctuation of the engine does not exceed the preset value; excessive fluctuation will reduce the detection accuracy; through testing, in this embodiment, the actual intake air density fluctuation of the engine does not exceed ±50mg / l / 10ms.

[0099] (2) Throttle opening fluctuation does not exceed the preset value; excessive fluctuation leads to reduced detection accuracy; through testing and verification, in this embodiment, throttle opening fluctuation does not exceed ±5% / 10ms;

[0100] (3) The engine operating time in this engine driving cycle exceeds the preset time, and the engine driving cycle in this example is 30 minutes.

[0101] The effectiveness can be judged only when the above conditions are met simultaneously:

[0102] When V = 1, if |p ThrBfAct (0)'-p ThrBfAct (0) | is greater than the preset value C1 (the example takes 5 kPa), it is judged that the throttle inlet pressure signal has a preliminary fault, otherwise it is judged that the throttle inlet pressure signal has no preliminary fault; wherein the preset value C1 = 5 x (1 + r Lrn ), r Lrn is the self-learning correction coefficient of the preset value C1, and its default value is 0, which can be saved after the vehicle is powered off;

[0103] When V = 2, if |p ThrBfAct (0)'-p ThrBfAct (0) |, |p ThrBfAct (1)'-p ThrBfAct (1) | are all greater than the preset value C1, it is judged that the throttle inlet pressure signal has a preliminary fault, otherwise it is judged that the throttle inlet pressure signal has no preliminary fault;

[0104] When V = 3, if |p ThrBfAct (0)'-p ThrBfAct (0) |, |p ThrBfAct (1)'-p ThrBfAct (1) |, |p ThrBfAct (2)'-p ThrBfAct (2) | are all greater than the preset value C1, it is judged that the throttle inlet pressure signal has a preliminary fault, otherwise it is judged that the throttle inlet pressure signal has no preliminary fault;

[0105] When V = 4, if |p ThrBfAct (0)'-p ThrBfAct (0) |, |p ThrBfAct (1)'-p ThrBfAct (1) |, |p ThrBfAct (2)'-p ThrBfAct (2) |, |p ThrBfAct (3)'-p ThrBfAct (3) | are all greater than the preset value C1, it is judged that the throttle inlet pressure signal has a preliminary fault, otherwise it is judged that the throttle inlet pressure signal has no preliminary fault;

[0106] When V = 5, if |p ThrBfAct (0)'-p ThrBfAct (0) |, |p ThrBfAct (1)'-pThrBfAct (1)|, |p ThrBfAct (2)'-p ThrBfAct (2)|, |p ThrBfAct (3)'-p ThrBfAct (3)|, |p ThrBfAct (4)'-p ThrBfAct (4)|, |p ThrBfAct (5)'-p ThrBfAct (5)|, |p ThrBfAct (6)'-p ThrBfAct (6)|, |p ThrBfAct (7)'-p ThrBfAct (7)|, |p ThrBfAct (8)'-p ThrBfAct (8)|, |p ThrBfAct (9)'-p ThrBfAct (9)|, |p ThrBfAct (10)'-p ThrBfAct (10)|, |p If all of |p

[0107] If V = 6, if |p ThrBfAct (0)'-p ThrBfAct (0)|, |p ThrBfAct (1)'-p ThrBfAct (1)|, |p ThrBfAct (2)'-p ThrBfAct (2)|, |p ThrBfAct (3)'-p ThrBfAct (3)|, |p ThrBfAct (4)'-p ThrBfAct (4)|, |p ThrBfAct (5)'-p ThrBfAct (5)|, |p If all of |p

[0108] The self-learning correction coefficient r Lrn of the preset value C1 is updated as follows: the effective number CNT1 of times when the throttle inlet pressure signal is judged not to have a preliminary fault and the ineffective number CNT2 of times when the throttle inlet pressure signal is judged to have a preliminary fault are recorded respectively under different sampling numbers V, wherein CNT1 and CNT2 are updated at most once per vehicle driving cycle: if CNT1≥160 and CNT2≤10, then r Lrn (z) = r Lrn (z) - 0.005; if CNT1≤10 and CNT2≥160, then r Lrn (z) = r Lrn (z) + 0.012; otherwise, r Lrn (z) = r Lrn (z); wherein r L rn(z) is the self-learning correction coefficient of the preset value C1 updated last time.

[0109] If CNT1+CNT2>200, CNT1180, and then the throttle inlet pressure signal is judged to have a fault, otherwise the throttle inlet pressure signal is judged not to have a fault; and when the throttle inlet pressure signal is judged to have a fault, CNT1 and CNT2 are cleared, and the counting is restarted when the next condition is met.

[0110] In the embodiment, the second method is:

[0111] When the judgment condition of the steady working condition of the throttle inlet pressure is met, the average value of the throttle inlet pressure and the average value of the throttle outlet pressure in a preset time are obtained.

[0112] According to the average value of the throttle inlet pressure, the average value of the throttle outlet pressure and a self-learning correction coefficient, it is judged whether the throttle inlet pressure signal is faulty.

[0113] Specifically, the second method is specifically:

[0114] When the judgment condition of the steady working condition of the throttle inlet pressure is met, the average value of the throttle inlet pressure in a preset time t3 is obtained and the average value of the throttle outlet pressure

[0115] If , it is judged that the throttle inlet pressure signal is faulty, otherwise it is judged that the throttle inlet pressure signal is not faulty.

[0116] Wherein, the preset time t3 is 2s in the example, and r Adpt is a self-learning correction coefficient, and the default value is 0, which can be saved when the vehicle is powered off.

[0117] The self-learning correction coefficient r Adpt is obtained as follows: record the number CNT3 of times that meet the judgment condition of the steady working condition of the throttle inlet pressure, record the number CNT4 of times that meet the judgment condition of the steady working condition of the throttle inlet pressure , record the number CNT5 of times that meet the judgment condition of the steady working condition of the throttle inlet pressure , and CNT3, CNT4 and CNT5 are updated at most once in each driving cycle of the vehicle.

[0118] If CNT3≥200, CNT4≥160, and CNT5≤10, then r Adpt =r Adpt (z)-0.01.

[0119] If CNT3≥200, CNT4≤10, and CNT5≥130, then r Adpt =r Adpt (z)+0.015.

[0120] In other cases, r Adpt =r Adpt (z).

[0121] Wherein r Adpt(z) is the self-learning correction coefficient of the last update; when CNT3≥200, the self-learning correction coefficient r Adpt After updating, CNT3, CNT4 and CNT5 are reset to 0 until the next condition is met to start accumulating the count again.

[0122] In this embodiment, the judgment condition for the stable working condition of the throttle inlet pressure is:

[0123] (1) the engine is in operation;

[0124] (2) the target intake amount is stable;

[0125] rho DesFilter (N) = K Rho × [rho DesRaw (N) - rho DesFilter (N-1)] + rho DesFilter (N-1); wherein rho DesRaw is the target intake amount, rho DesRaw (N) is the target intake amount of the Nth sampling period, rho DesFilter is the first-order low-pass filtered target intake amount, rho DesFilter (N) is the filtered target intake amount of the Nth sampling period, rho DesFilter (N-1) is the filtered target intake amount of the (N-1)th sampling period, N = 1, 2, 3…, and rho DesFilter (0) is equal to the target intake amount rho DesRaw (0) at the 0th sampling period; the sampling period interval At is 10 ms in this example. K Rho is the coefficient: In this example, k Rho is calibrated at a speed of 1000 rpm, The purpose of such setting is to normalize the processing, without making special calibration at different speeds, only k Rho at 1000 rpm needs to be calibrated, thereby reducing the calibration test work, wherein n is the engine speed, k Rho is the air amount filtering coefficient, which is taken as 0.02 in this example.

[0126] When |rho DesRaw (N) - rho DesFilter (N)| < min[rho DesRaw (N), rho DesFilter (N)] x r RhoLim , the condition is continuously met for T Rho , which indicates that the target intake amount is in a stable state (small air amount fluctuation). In this example, r RhoLim is taken as 0.05, and TRho The 0.4s is taken in this example.

[0127] (3) The actual intake pressure at the throttle outlet is stable;

[0128] p ManFilter (N) = K Man × [p Man (N) - p ManFilter (N-1)] + p ManFilter (N-1); wherein p Man is the intake pressure at the throttle outlet, p Man (N) is the intake pressure at the throttle outlet in the Nth sampling period, p ManFilter is the intake pressure at the throttle outlet after first-order low-pass filtering, p ManFilter (N) is the filtered intake pressure at the throttle outlet in the Nth sampling period, p ManFilter (N-1) is the filtered intake pressure at the throttle outlet in the (N-1)th sampling period, and N = 1, 2, 3, …, p ManFilter (0) is the intake pressure at the throttle outlet in the 0th sampling period p Man (0); the sampling period interval Δt is 10 ms in this example. K Man is a coefficient: The k Man is calibrated at a speed of 1000 rpm in this example, The purpose of such a setting is to normalize the process, without the need for special calibration at different speeds, only the k Man of the 4-cylinder engine and the speed of 1000 rpm needs to be calibrated, thereby reducing the calibration test work), wherein n is the engine speed, k Man is the throttle outlet intake pressure filtering coefficient, which is taken as 0.02 in this example.

[0129] When |p Man (N) - p ManFilter (N)| < min[p Man (N), p ManFilter (N)] x r ManLim , the condition is continuously met for a time T Man , indicating that the intake pressure is in a stable state (with small fluctuations in intake pressure). Wherein r ManLim is taken as 0.05 in this example, and T Man is taken as 0.4s in this example.

[0130] (4) The engine speed fluctuation does not exceed the preset range, which is ±15 rpm in this example;

[0131] (5) The opening degree of the supercharger actuator is equal to its full opening degree, which is the opening degree corresponding to the maximum supercharging capacity of the supercharger;

[0132] (6) Throttle opening is greater than the preset value, which is 95% in this example;

[0133] (7) No fault was detected in the throttle outlet pressure signal;

[0134] (8) The product of the engine's short-term fuel trim and long-term fuel trim is within a preset range (0.97-1.03 in this example) and exceeds a preset time t2 (5s in this example); the acquisition of the short-term fuel trim can be found in the patent "A Short-Term Fuel Trim Control Method and Control System for an Engine" with publication number CN113847155A; the acquisition of the long-term fuel trim can be found in the patent "A Self-Learning Method for Long-Term Fuel Trim of a Gasoline Engine" with publication number CN111412074A. If the product of the engine's short-term fuel trim and long-term fuel trim is small, it indicates that the difference between the requested fuel injection quantity and the actual fuel injection quantity is small, the accuracy of the requested fuel injection quantity calculated based on the intake air volume is high, the accuracy of the engine intake air volume is high, and the signal from the pressure sensor after the throttle valve is accurate.

[0135] S2, determine whether the throttle inlet pressure signal is faulty based on the results of the first method and the second method.

[0136] Specifically, in this embodiment, the method for determining whether the throttle inlet pressure signal is faulty based on the results of the first method and the second method is as follows:

[0137] If, during this driving cycle, the second method determines that the throttle inlet pressure signal is faulty, while the first method determines that the throttle inlet pressure signal is not faulty, then the final determination is that the throttle inlet pressure signal is not faulty, and the self-learning correction coefficient r of the preset value C1 is updated. Lrn =r Lrn (z)+0.03, update the self-learning correction coefficient r Adpt =r Adpt (z)-0.005;

[0138] If, during this driving cycle, the second method determines that the throttle inlet pressure signal is not faulty, but the first method determines that the throttle inlet pressure signal is faulty, then the final determination is that the throttle inlet pressure signal is faulty, and the self-learning correction coefficient r of the preset value C1 is updated. Lrn =r Lrn (z)-0.04, update the self-learning correction coefficient r Adpt =r Adpt (z)-0.05;

[0139] If the second method judges that the throttle inlet pressure signal does not appear fault in the current driving cycle, and the first method judges that the throttle inlet pressure signal does not appear fault, it is finally judged that the throttle inlet pressure signal does not appear fault, and the self-learning correction coefficient r of the preset value C1 is updated Adpt = r Adpt (z), the self-learning correction coefficient r is updated Lrn = r Lrn (z);

[0140] If the second method judges that the throttle inlet pressure signal appears fault in the current driving cycle, and the first method judges that the throttle inlet pressure signal appears fault, it is finally judged that the throttle inlet pressure signal appears fault, and the self-learning correction coefficient r of the preset value C1 is updated Adpt = r Adpt (z), the self-learning correction coefficient r is updated Lrn = r Lrn (z);

[0141] Wherein r Adpt (z) is the last updated self-learning correction coefficient; wherein r Lrn (z) is the last updated self-learning correction coefficient of the preset value C1.

[0142] In summary, the application provides a kind of failure judgment method for improving intake pressure control, which can check the rationality of the pressure signal of the pressure sensor before throttle.

[0143] It should be noted that according to the needs of implementation, each step described in the present application can be split into more steps, or two or more steps or part of the operation can be combined into a new step to achieve the purpose of the present application.

[0144] Those skilled in the art will readily understand that the above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method of improving failure determination of intake air pressure control, characterized by, The method comprises the following steps: checking the throttle inlet pressure signal by using the first method and the second method respectively; judging whether the throttle inlet pressure signal is faulty according to the results of the first method and the second method; the first method is filtering the engine speed to obtain a filtered engine speed; reading the throttle inlet pressure signal for a plurality of times, and estimating the throttle inlet pressure signal in the next sampling period by using the throttle inlet pressure signal at a certain time; determining the sampling times for checking the throttle inlet pressure signal according to the filtered engine speed and the original real-time engine speed; judging whether the throttle inlet pressure signal is faulty according to the sampling times, the estimated value of the throttle inlet pressure signal and the actual value of the throttle inlet pressure signal; the second method is: when the judgment condition of the stable working condition of the throttle inlet pressure is met, obtaining the average value of the throttle inlet pressure and the average value of the throttle outlet pressure in a preset time; judging whether the throttle inlet pressure signal is faulty according to the average value of the throttle inlet pressure, the average value of the throttle outlet pressure and the self-learning correction coefficient.

2. The method of claim 1, wherein In the first method: The filtered engine speed n Filt is calculated as follows: the current sample period wave engine speed n Filt (m) and the filtered engine speed n Filt (m+1) of the next sample period and the raw real-time engine speed n Raw read by the sensor are related as follows: n Filt (m+1) = k x n Raw + (1 - k) x n Filt (m); where m = 0, 1, 2,..., n Filt (0) take 0; k is a filter coefficient.

3. The method of claim 2, wherein the failure determination is made when the pressure difference between the intake air pressure and the target intake air pressure is greater than a predetermined value. In the second method: the specific method for judging whether the throttle inlet pressure signal is faulty is: When the condition of the steady state of the throttle inlet pressure is met, the average value of the throttle inlet pressure in a preset time t3 is obtained and the average value of the throttle outlet pressure If then determine that the throttle inlet pressure signal is malfunctioning, otherwise determine that the throttle inlet pressure signal is not malfunctioning; wherein said r Adpt is a self-learning correction factor, with a default value of 0, which can be saved at vehicle power down.

4. The method of claim 3, wherein the failure determination is made when the pressure difference between the intake air pressure and the target intake air pressure is greater than a predetermined value. The self-learning correction coefficient r Adpt The acquisition method is as follows: record the number CNT3 of times that the throttle inlet pressure stable working condition judgment condition is met, record the number CNT4 of times that the throttle inlet pressure stable working condition judgment condition is met after The acquisition method is as follows: record the number CNT3 of times that the throttle inlet pressure stable working condition judgment condition is met, record the number CNT4 of times that the throttle inlet pressure stable working condition judgment condition is met after The CNT3, CNT4 and CNT5 are each updated at most once per vehicle driving cycle. If CNT3 ≥ 200, CNT4 ≥ 160, and CNT5 ≤ 10, then r Adpt = r Adpt (z) - 0.01; If CNT3 ≥ 200, CNT4 ≤ 10, and CNT5 ≥ 130, then r Adpt = r Adpt (z) + 0.015; In other cases, r Adpt = r Adpt (z); where r Adpt (z) is the self-learning correction coefficient of the last update; when CNT3≥200, then the self-learning correction coefficient r Adpt After updating, CNT3, CNT4 and CNT5 are reset to 0 until the next condition is met and the accumulation counting is restarted.

5. The method of claim 1, wherein the method is characterized by: The judgment condition of the stable working condition of the throttle inlet pressure is: (1) the engine is running; (2) the target intake amount is stable; (3) the actual intake pressure of the throttle outlet is stable; (4) the engine speed fluctuation does not exceed a preset range; (5) the opening degree of the supercharging actuator is equal to its full opening degree; (6) the throttle opening degree is greater than a preset value; (7) the throttle outlet pressure signal is not detected to be faulty; (8) the product of the short-term fuel correction and the long-term fuel correction is within a preset range, and exceeds a preset time.

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