Method for judging abnormality of intake system pressure sensor under steady state operating condition

Abstract

The application discloses a kind of steady-state condition under intake system pressure sensor abnormality judging method, comprising: when throttle inlet pressure steady-state condition judging condition meets, obtaining preset time within throttle inlet pressure average and throttle outlet pressure average;According to the throttle inlet pressure average, the throttle outlet pressure average and self-learning correction coefficient, whether throttle inlet pressure signal appears fault is judged.The method provided by the application can identify whether pressure signal is abnormal under steady-state condition.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of engine control, in particular to a method for judging abnormality of an intake system pressure sensor under a steady state condition. BACKGROUND

[0002] As the core information of intake control, the pressure sensor signal needs to be identified for abnormality under a steady state condition, so as to give an early warning and avoid damage to the engine and personal safety due to abnormal engine control.

[0003] Patent No. 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 method for judging abnormality of an intake system pressure sensor under a steady state condition.

[0004] Patent No. 202110518171.3 discloses a "method and device for measuring 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 method for judging abnormality of an intake system pressure sensor under a steady state condition. SUMMARY

[0005] The present application solves the technical problems of the prior art by providing a method for judging abnormality of an intake system pressure sensor under a steady state condition, which can identify whether the pressure signal is abnormal under a steady state condition, so as to give an early warning and avoid damage to the engine and personal safety due to abnormal engine control.

[0006] To achieve the above-mentioned purpose, according to one aspect of the present application, a method for judging abnormality of an intake system pressure sensor under a steady state condition is provided, comprising:

[0007] When the throttle inlet pressure steady state condition judgment condition is met, the average value of the throttle inlet pressure and the average value of the throttle outlet pressure within a preset time are obtained;

[0008] According to the average value of the throttle inlet pressure, the average value of the throttle outlet pressure and the self-learning correction coefficient, it is judged whether the throttle inlet pressure signal is faulty.

[0009] In the above-mentioned solution, the specific method for judging whether the throttle inlet pressure signal is faulty is:

[0010] When the throttle inlet pressure steady state condition judgment condition is met, the average value of the throttle inlet pressure within a preset time t3 is obtained and the average value of the throttle outlet pressure

[0011] If , it is determined that the throttle inlet pressure signal is faulty, otherwise it is determined that the throttle inlet pressure signal is not faulty.

[0012] In the above scheme, r Adpt is a self-learning correction coefficient, and the default value is 0, which can be saved when the vehicle is powered off.

[0013] In the above scheme, the self-learning correction coefficient r Adpt is obtained as follows: record the number of times CNT3 that meet the throttle inlet pressure stable working condition determination condition, record the number of times CNT4 that meet the throttle inlet pressure stable working condition determination condition , record the number of times CNT5 that meet the throttle inlet pressure stable working condition determination condition , and the CNT3, CNT4, CNT5 are all updated at most once per vehicle driving cycle;

[0014] If CNT3≥200, CNT4≥160, and CNT5≤10, then r Adpt =r Adpt (z)-0.01;

[0015] If CNT3≥200, CNT4≤10, and CNT5≥130, then r Adpt =r Adpt (z)+0.015;

[0016] In other cases, r Adpt =r Adpt (z);

[0017] Where r Adpt (z) is the last updated self-learning correction coefficient; when CNT3≥200, then after updating the self-learning correction coefficient r Adpt , CNT3, CNT4 and CNT5 are all reset to 0 until the next condition is met and the counting starts again.

[0018] In the above scheme, the throttle inlet pressure stable working condition determination condition is:

[0019] (1) The engine is in operation;

[0020] (2) The target intake amount is stable;

[0021] (3) The actual intake pressure at the throttle outlet is stable;

[0022] (4) The engine speed fluctuation does not exceed a preset range;

[0023] (5) The opening degree of the booster actuator is equal to its full opening degree;

[0024] (6) Throttle opening is greater than the preset value;

[0025] (7) No fault was detected in the throttle outlet pressure signal;

[0026] (8) The product of the engine's short-term fuel correction and long-term fuel correction is within the preset range and exceeds the preset time t2.

[0027] In the above scheme, the method for determining that the target intake volume is stable is as follows:

[0028] rho DesFilter (N)=K Rho ×[rho DesRaw (N)-rho DesFilter (N-1)]+rho DesFilter (N-1); where rho DesRaw For the target intake volume, rho DesRaw (N) represents the target intake volume in the Nth sampling period, rho DesFilter The target intake volume after first-order low-pass filtering, rho DesFilter (N) represents the filtered target intake volume in the Nth sampling period, rho DesFilter (N-1) represents the filtered target intake volume for the (N-1)th sampling period, where N = 1, 2, 3, ..., rho DesFilter (0) equals the target intake volume rho at the 0th sampling period. DesRaw (0); Sampling period interval Δt; K Rho Here are the coefficients, and here are the preset values: Where n is the engine speed, k Rho This is the gas volume filtering coefficient, which is a preset value.

[0029] In |rho DesRaw (N)-rho DesFilter (N)| <min[rho DesRaw (N), rho DesFilter (N)]×r RhoLim The condition is met continuously for a time T. Rho This indicates that the target intake volume is in a stable state. Where r... RhoLim T is the preset value. Rho This is the default value.

[0030] In the above scheme, the method for determining whether the actual intake pressure at the throttle outlet is stable is as follows:

[0031] p ManFilter (N)=K Man ×[p Man (N)-pManFilter [(N-1)]+p ManFilter (N-1); where p Man p is the intake pressure at the throttle outlet. Man (N) represents the throttle outlet intake pressure during the Nth sampling period, p ManFilter p is the throttle outlet intake pressure after first-order low-pass filtering. ManFilter (N) represents the filtered throttle outlet intake pressure during the Nth sampling period, p ManFilter (N-1) represents the filtered throttle outlet intake pressure during the (N-1)th sampling period, where N = 1, 2, 3, ..., p ManFilter (0) equals the throttle outlet intake pressure p during the 0th sampling period. Man (0); The sampling period interval Δt is a preset value; K Man Here are the coefficients, and here are the preset values: Where n is the engine speed, k Man This is the throttle valve outlet intake pressure filter coefficient, which is a preset value.

[0032] In |p Man (N)-p ManFilter (N)| <min[p Man (N), p ManFilter (N)]×r ManLim The condition is met continuously for a time T. Man This indicates that the intake pressure is in a stable state; where r ManLim T is the preset value. Man This is the default value.

[0033] In the above scheme, the full opening degree is the opening degree corresponding to the maximum boosting capacity of the turbocharger.

[0034] In the above scheme, the product of the engine's short-term fuel correction and long-term fuel correction is within a preset range and exceeds a preset time t2, wherein the preset range is 0.97-1.03 and the preset time t2 is 5s.

[0035] In the above scheme, the engine speed fluctuation does not exceed a preset range, which is ±15 rpm.

[0036] In the above scheme, the throttle opening is greater than a preset value, and the preset value is 95%.

[0037] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects:

[0038] The application provides a method for judging abnormality of an intake system pressure sensor under a steady state condition. BRIEF DESCRIPTION OF DRAWINGS

[0039] 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 accompanying drawings are included to provide a further understanding of the preferred embodiments and are incorporated into and constitute a part of this specification. It will be appreciated that the same reference numerals are used to refer to like components throughout.

[0040] Figure 1 It is a schematic diagram of the intake system of the exhaust turbocharged engine in the embodiment of the application.

[0041] Figure 2 It is a flowchart of the method for judging abnormality of the intake system pressure sensor under the steady state condition in the embodiment of the application. DETAILED DESCRIPTION

[0042] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and should not be used to 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.

[0043] It should be understood that the size of the serial number of each step in the embodiment does not mean the order of execution, and the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0044] Embodiment 1

[0045] The main components of the exhaust turbocharged engine intake system based on the present application include: atmospheric pressure sensor, supercharger, electronic pressure relief valve, intercooler, throttle valve front temperature pressure sensor, throttle valve, throttle valve rear intake temperature pressure sensor, carbon canister solenoid valve, EGR, VVT system, etc., as shown in Figure 1The atmospheric pressure sensor can read atmospheric pressure, and is installed in a PCB board of the controller ECU. The supercharger includes a supercharger body and a waste gas bypass valve. The waste gas bypass valve is adjusted to control the supercharging pressure. The electronic pressure relief valve is used to open the pressure relief valve to avoid the flow back and forth in the supercharger compressor when the engine has a torque reduction request, to improve the supercharger surge, and to improve the engine life and NVH. The temperature and pressure sensors before the throttle valve can read the temperature and pressure of the supercharged gas before the throttle valve. The intercooler is a mechanical part and is not controlled. The intercooler is located between the supercharger compressor and the throttle valve, and cools the supercharged gas. The temperature and pressure sensors after the throttle valve can read the temperature and pressure of the supercharged gas before the throttle valve. The carbon can electromagnetic valve is used to introduce the fuel vapor into the combustion and prevent the evaporation into the atmosphere.

[0046] EGR, i.e. exhaust gas recirculation, sends part of the exhaust gas of the engine back to the intake manifold, and enters the cylinder again with fresh mixture. VVT is used to adjust the intake (exhaust) amount, valve opening and closing time, angle, and adjust the amount of air entering the cylinder. The throttle valve inlet pressure signal verification in the application is to verify the reasonableness of the pressure signal of the pressure sensor before the throttle valve.

[0047] According to one aspect of the application, a steady-state working condition intake system pressure sensor abnormality judgment method is provided, referring to Figure 2 , comprising:

[0048] When the throttle valve inlet pressure stable working condition judgment condition is met, the average value of the throttle valve inlet pressure in a preset time t3 is obtained and the average value of the throttle valve outlet pressure

[0049] If , it is judged that the throttle valve inlet pressure signal is faulty, otherwise it is judged that the throttle valve inlet pressure signal is not faulty.

[0050] 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.

[0051] The self-learning correction coefficient r Adpt is obtained as follows: record the number CNT3 of times that meet the throttle valve inlet pressure stable working condition judgment condition, record the number CNT4 of times that meet the throttle valve inlet pressure stable working condition judgment condition , record the number CNT5 of times that meet the throttle valve inlet pressure stable working condition judgment condition , and CNT3, CNT4 and CNT5 are updated at most once per driving cycle of the vehicle.

[0052] If CNT3≥200, CNT4≥160, and CNT5≤10, then r Adpt =r Adpt (z)-0.01;

[0053] If CNT3 ≥ 200, CNT4 ≤ 10, and CNT5 ≥ 130, then r Adpt =r Adpt (z)+0.015;

[0054] In other cases, r Adpt =r Adpt (z);

[0055] Where r Adpt (z) represents the self-learning correction coefficient from the last update; when CNT3 ≥ 200, then the self-learning correction coefficient r Adpt After the update is complete, CNT3, CNT4 and CNT5 will all be reset to 0, and the counting will restart when the next condition is met.

[0056] In this embodiment, the condition for determining stable throttle inlet pressure is as follows:

[0057] (1) The engine is running;

[0058] (2) The target air intake volume is stable;

[0059] rho DesFilter (N)=K Rho ×[rho DesRaw (N)-rho DesFilter (N-1)]+rho DesFilter (N-1); where rho DesRaw For the target intake volume, rho DesRaw (N) represents the target intake volume in the Nth sampling period, rho DesFilter The target intake volume after first-order low-pass filtering, rho DesFilter (N) represents the filtered target intake volume in the Nth sampling period, rho DesFilter (N-1) represents the filtered target intake volume for the (N-1)th sampling period, where N = 1, 2, 3, ..., rho DesFilter (0) equals the target intake volume rho at the 0th sampling period. DesRaw (0); Sampling period interval Δt, which is 10ms in this example. K Rho For coefficients: (This example k) Rho The calibration speed is 1000 rpm. The purpose of this setting is for normalization; at different speeds, no special calibration is needed, only k at 1000 rpm.Rho , where n is engine speed, k Rho is air mass filter coefficient, and in this example, k

[0060] In |rho DesRaw (N) - rho DesFilter (N) | < min[rho DesRaw (N), rho DesFilter (N)] x r RhoLim , the condition continuously satisfied for time T Rho , indicates that the target intake air mass is in a stable state (air mass fluctuation is small). In this example, r RhoLim = 0.05, and T Rho = 0.4 s.

[0061] (3) The actual intake air pressure at the throttle outlet is stable;

[0062] p ManFilter (N) = K Man x [p Man (N) - p ManFilter (N-1)] + p ManFilter (N-1); where p Man is the throttle outlet intake air pressure, p Man (N) is the throttle outlet intake air pressure at the Nth sampling period, p ManFilter is the first-order low-pass filtered throttle outlet intake air pressure, p ManFilter (N) is the filtered throttle outlet intake air pressure at the Nth sampling period, p ManFilter (N-1) is the filtered throttle outlet intake air pressure at the (N-1)th sampling period, N = 1, 2, 3,..., and p ManFilter (0) is equal to the throttle outlet intake air pressure p Man (0) at the 0th sampling period. The sampling period interval At is 10 ms in this example. K Man is the coefficient: In this example, k Man is calibrated at 1000 rpm, The purpose of such a setting is to normalize the process, and at different speeds, no special calibration is required, only the 4-cylinder engine and k Man , where n is engine speed, k Man is the throttle outlet intake air pressure filter coefficient, and in this example, k

[0063] In |p Man (N) - p ManFilter (N) | < min[p Man(N), p ManFilter (N)] x r ManLim The condition is continuously met for a time reaching T Man The latter indicates that the intake air pressure is in a stable state (the intake air pressure fluctuates less). Wherein, r ManLim In this example, 0.05 is taken, T Man In this example, 0.4s is taken.

[0064] (4) The engine speed fluctuation does not exceed the preset range, and in this example, ±15 rpm is taken;

[0065] (5) The boost actuator opening degree is equal to its full opening degree, and the full opening degree is the opening degree corresponding to the maximum boost capacity of the supercharger;

[0066] (6) The throttle opening degree is greater than the preset value, and in this example, 95% is taken;

[0067] (7) The throttle outlet pressure signal is not detected to have a fault;

[0068] (8) The product of the engine short-term fuel correction and the long-term fuel correction is within the preset range (in this example, 0.97-1.03), and exceeds the preset time t2 (in this example, 5s); wherein the short-term fuel correction can be obtained from the patent with publication number CN113847155A entitled “Engine Short-term Fuel Correction Control Method and Control System”; the long-term fuel correction can be obtained from the patent with publication number CN111412074A entitled “Self-learning method for long-term fuel correction of gasoline engine”. If the product of the engine short-term fuel correction and the long-term fuel correction is small, it means that the difference between the requested fuel injection amount and the actual fuel injection amount is small, the accuracy of the engine requested fuel injection amount calculated based on the intake air amount is high, the accuracy of the engine intake air amount is high, and the throttle outlet pressure sensor signal is accurate.

[0069] In summary, the method for judging the abnormality of the intake air system pressure sensor under the steady state working condition provided by the present application can identify whether the pressure signal is abnormal under the steady state working condition, thereby providing early warning and avoiding damage to the engine and personal safety due to abnormal engine control.

[0070] It should be noted that, according to the needs of implementation, each step described in this application can be split into more steps, or two or more steps or part of the operations of the steps can be combined into new steps to achieve the purpose of the present application.

[0071] 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, and any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method of determining abnormality of an intake system pressure sensor in a steady state operation, characterized by, Comprise: When the judgment condition of the steady state of the throttle inlet pressure is met, obtain the average value of the throttle inlet pressure and the average value of the throttle outlet pressure within a preset time; According to the average value of the throttle inlet pressure, the average value of the throttle outlet pressure and the self-learning correction coefficient, judge whether the throttle inlet pressure signal is faulty or not; The specific method for judging whether the throttle inlet pressure signal is faulty or not 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 when the vehicle is powered off; 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 number CNT5 of times that the throttle inlet pressure stable working condition judgment condition is met after CNT3, CNT4, CNT5 are all 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.

2. The method according to claim 1, characterized by The judgment condition of the steady state 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 supercharger 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 engine short-term fuel correction and the long-term fuel correction is within a preset range and exceeds a preset time.

3. The method according to claim 2, characterized by, The method for judging that the target intake amount is stable is: rho DesFilter (N) = K Rho × [rho DesRaw (N) - rho DesFilter (N - 1)] + rho DesFilter (N - 1); wherein, rho DesRaw is a target intake air amount, rho DesRaw (N) is a target intake air amount of an Nth sampling period, rho DesFilter is a first-order low-pass filtered target intake air amount, rho DesFilter (N) is a filtered target intake air amount of the Nth sampling period, rho DesFilter (N - 1) is a filtered target intake air amount of an (N - 1)th sampling period, N = 1, 2, 3, …, rho DesFilter (0) is the target intake air amount at the 0th sampling period, rho De s Raw (0); a sampling period interval Δt; K Rho is a coefficient, and is a preset value: wherein n is an engine speed, k Rho is an air amount filter coefficient, and is a preset value; In |rho DesRaw (N)-rho DesFilter (N)|<min[rho DesRaw (N), rho DesFilter (N)]×r RhoLim The condition is continuously satisfied for a time T Rho After which the target intake amount is in a steady state; wherein r RhoLim Is a preset value, and T Rho Is a preset value.

4. The method of claim 2, wherein The method for judging that the actual intake pressure of the throttle outlet is stable is: p ManFilter (N) = K Man × [p Man (N) - p ManFilter (N - 1)] + p ManFilter (N - 1); wherein p Man is the throttle outlet intake air pressure, p Man (N) is the throttle outlet intake air pressure in the Nth sampling period, p ManFilter is the first-order low-pass filtered throttle outlet intake air pressure, p ManFilter (N) is the filtered throttle outlet intake air pressure in the Nth sampling period, p ManFilter (N - 1) is the filtered throttle outlet intake air pressure in the (N - 1)th sampling period, N = 1, 2, 3, …, p ManFilter (0) is the throttle outlet intake air pressure p Man (0) in the 0th sampling period; the sampling period interval Δt is a preset value; K Man is a coefficient, and is a preset value: wherein n is the engine speed, k Man is a throttle outlet intake air pressure filtering coefficient, and is a preset value; In |p Man (N)-p ManFilter (N)|<min[p Man (N), p ManFilter (N)]×r ManLim The condition is continuously met for a time T Man After that, it indicates that the intake pressure is in a steady state; wherein r ManLim is a preset value, and T Man is a preset value.

5. The method of claim 2, wherein The full opening degree is the opening degree corresponding to the maximum supercharging capacity of the supercharger.

6. The method of claim 2, wherein The product of the engine short-term fuel correction and the long-term fuel correction is within a preset range and exceeds a preset time t2, wherein the preset range is 0.97-1.03 and the preset time t2 is 5s.

7. The method of claim 2, wherein The engine speed fluctuation does not exceed a preset range, and the preset range is ±15rpm.

8. The method of claim 1, wherein The throttle opening degree is greater than a preset value, and the preset value is 95%.

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