Intake manifold leak detection and aftertreatment method, apparatus, device, and storage medium

Abstract

The application discloses an air intake manifold leakage detection and post-processing method, device, equipment and storage medium, wherein the method comprises the following steps: determining the pressure difference between the target intake pressure and the actual intake pressure of the engine and the actual intake pressure change rate according to the target intake pressure and the actual intake pressure of the engine; determining the severity level of the air intake manifold leakage according to the pressure difference and the actual intake pressure change rate; and executing corresponding air intake manifold leakage post-processing steps according to the severity level, wherein the air intake manifold leakage post-processing steps are used for controlling the engine speed fluctuation. According to the pressure difference between the target intake pressure and the actual intake pressure and the actual intake pressure change rate, the application judges whether the air intake manifold leaks, executes corresponding post-processing steps according to the severity level of the air intake manifold leakage, avoids the engine speed fluctuation being too large, simultaneously avoids the engine being off or the speed rising too fast, and ensures that the vehicle can limp to a safe position when the air intake manifold leaks.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of engine control, and particularly relates to an intake manifold leakage detection and post-processing method, device, equipment and storage medium. BACKGROUND

[0002] During the driving of the automobile, the intake manifold provides sufficient intake air for each cylinder of the engine. In a direct injection engine, air flows through the intake manifold into the cylinder through the throttle valve, mixes with fuel and burns. In a port injection engine, after the throttle valve is opened, the mixed gas of air and fuel enters the cylinder through the intake manifold and burns in the cylinder. In both direct injection engines and port injection engines, the intake manifold, as one of the most important components of the engine, is a key factor affecting the power and fuel consumption of the engine.

[0003] When the intake manifold leaks, the change in engine intake air volume will cause a sudden change in engine power. Unstable control of engine intake air volume will also cause unstable combustion of the mixed gas in the cylinder, which will further cause engine stall or rapid change in engine speed, endangering driving safety.

[0004] The prior art does not provide a processing method for the leakage of the intake manifold. Patent CN109083756B discloses an engine intake fault detection method and device. The detection method in the patent determines whether the engine has an intake fault by the deviation value of the intake pressure under the current working condition and the preset standard intake pressure. The abnormal condition preset in the method does not include the leakage of the intake manifold, and no post-processing method for abnormal conditions is provided. SUMMARY

[0005] In view of the above defects or improvement needs of the prior art, the purpose of the present application is to provide an intake manifold leakage detection and post-processing method, device, equipment and storage medium.

[0006] To achieve this purpose, the present application adopts the following technical solutions:

[0007] As an aspect of the present application, an intake manifold leakage detection and post-processing method is provided, comprising the following steps:

[0008] According to the target intake pressure of the engine and the actual intake pressure of the engine, the pressure difference between the target intake pressure and the actual intake pressure and the actual intake pressure change rate are determined;

[0009] According to the pressure difference and the actual intake pressure change rate, the severity level of the intake manifold leakage is determined;

[0010] According to the severity level, the corresponding intake manifold leakage post-processing step is executed, and the intake manifold leakage post-processing step is used to control the engine speed fluctuation.

[0011] Intake pressure refers to the gas pressure inside the intake manifold. Target intake pressure refers to the target value of the gas pressure in the intake manifold. The target intake pressure is an important parameter for controlling the target intake volume. Actual intake pressure refers to the actual value of the gas pressure in the intake manifold, which can be detected by sensors.

[0012] Further, the step of determining the severity level of the intake manifold leakage based on the pressure difference and the actual intake pressure change rate includes:

[0013] When the pressure difference is greater than the first pressure difference threshold and the actual intake pressure change rate is less than or equal to the first change threshold, the engine is determined to be in the first state.

[0014] When the cumulative time the engine spends in the first state is greater than a first preset time, the severity level is determined to be Level 1 L1.

[0015] The first differential pressure threshold is:

[0016] A1 = P Dsrd ·k1+c1;

[0017] Where A1 is the first differential pressure threshold, P Dsrd Let k1 be the target intake pressure, k1 be the first differential pressure coefficient, and c1 be the first compensation coefficient.

[0018] Furthermore, the step of performing after-treatment of the intake manifold leak according to the severity level includes:

[0019] When the severity level is Level 1 (L1), the following post-processing steps are performed:

[0020] Self-learning of effective throttle valve area;

[0021] Carbon canister control activation is prohibited;

[0022] The engine fuel cut-off command is prohibited from being triggered, meaning that fuel cut-off is not allowed in any cylinder of the engine.

[0023] Adjust the minimum allowable air volume for engine operation:

[0024] rho Min =k(n, P) Dsrd )·rho MinRaw ;

[0025] Among them, rho Min The minimum allowable gas volume for the modified engine operation, k(n, P) Dsrd ) represents the correction factor determined based on engine speed and target intake pressure, rho MinRaw The minimum air volume allowed for the engine to operate before the correction;

[0026] Correcting engine idle target speed:

[0027] n IdleDsrd ′ = max(n IdleDsrd (T, P Amb ), n IdleDsrdRaw );

[0028] wherein n IdleDsrd ′ is the corrected idle target speed, n IdleDsrd (T, P Amb ) is the idle target speed determined according to engine water temperature and atmospheric pressure, and n IdleDsrdRaw is the idle target speed under normal control.

[0029] Further, the step of determining the severity level of intake manifold leakage according to the pressure difference and the actual intake pressure change rate further comprises:

[0030] determining that the engine is in a second state when the pressure difference is less than a second pressure difference threshold and the actual intake pressure change rate is greater than or equal to a second change threshold;

[0031] determining that the severity level is a second level L2 when the cumulative time of the engine in the second state is greater than a second preset time;

[0032] wherein the second pressure difference threshold is:

[0033] A2 = -(P Dsrd · k2 + c2);

[0034] wherein A2 is the second pressure difference threshold, k2 is a second pressure difference coefficient, and c2 is a second compensation coefficient.

[0035] Further, the step of performing post-processing of intake manifold leakage according to the severity level further comprises:

[0036] when the severity level is the second level L2, performing the following post-processing steps:

[0037] closing the throttle effective area self-learning;

[0038] inhibiting the carbon canister control activation;

[0039] during the engine working cycle, performing cycle fuel cut control on each cylinder of the engine according to the ignition order, wherein the cycle fuel cut control is performed on the cylinder to be ignited in the current working cycle;

[0040] limiting the engine maximum speed, wherein the engine maximum speed is determined according to the throttle opening degree and the atmospheric pressure;

[0041] correcting the target air-fuel ratio:

[0042] AFR = k(n, P Diff ) · AFR Raw ;

[0043] wherein AFR is the corrected target air-fuel ratio, k(n, P Diff ) is a correction coefficient determined according to the engine speed and the pressure difference, AFR Raw is the target air-fuel ratio before correction.

[0044] Further, the step of determining the severity level of the intake manifold leakage according to the pressure difference and the actual intake pressure change rate further comprises:

[0045] determining that the engine is in a third state when the pressure difference is greater than or equal to a third pressure difference threshold and the pressure difference is less than or equal to a first pressure difference threshold;

[0046] determining that the severity level is a third level L3 when the cumulative time of the engine in the third state is greater than a third preset time;

[0047] wherein the third pressure difference threshold is:

[0048] A3 = P Dsrd · k2 + c2;

[0049] wherein A3 is the third pressure difference threshold.

[0050] Further, the step of performing the post-processing of the intake manifold leakage according to the severity level further comprises:

[0051] when the severity level is the third level L3, performing the following post-processing steps:

[0052] closing the throttle effective area self-learning;

[0053] inhibiting the carbon canister control activation;

[0054] limiting the engine maximum speed, wherein the engine maximum speed is determined according to the throttle opening degree and the atmospheric pressure;

[0055] optimizing the idle target speed:

[0056] n IdleDsrd ″ = n IdleDsrdRaw + P DiddFilt · (n IdleAct - n IdleDsrdRaw );

[0057] wherein n IdleDsrd ″ is the optimized idle target speed, P DiddFilt is the filtered value of the pressure difference, and n IdleAct is the engine speed at idle.

[0058] As another aspect of the present application, there is provided an intake manifold leakage detection and post-processing device, comprising:

[0059] a first module configured to determine a pressure difference between a target intake pressure of the engine and an actual intake pressure of the engine and an actual intake pressure change rate based on the target intake pressure and the actual intake pressure of the engine;

[0060] a second module configured to determine a severity level of the intake manifold leakage based on the pressure difference and the actual intake pressure change rate;

[0061] a third module configured to perform a corresponding intake manifold leakage post-processing step based on the severity level.

[0062] As another aspect of the present application, there is provided an electronic device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor implements the steps of the intake manifold leakage detection and post-processing method when executing the computer program.

[0063] As another aspect of the present application, there is provided a computer readable storage medium storing computer instructions, wherein the computer instructions cause the computer to perform the steps of the intake manifold leakage detection and post-processing method.

[0064] The present application has the following beneficial effects: For the intake manifold leakage detection and post-processing method, a pressure difference between a target intake pressure of the engine and an actual intake pressure of the engine and an actual intake pressure change rate are determined based on the target intake pressure and the actual intake pressure of the engine; a severity level of the intake manifold leakage is determined based on the pressure difference and the actual intake pressure change rate; and a corresponding intake manifold leakage post-processing step is performed based on the severity level, wherein the intake manifold leakage post-processing step is configured to control engine speed fluctuation. The present application determines whether the intake manifold leaks based on the pressure difference between the target intake pressure and the actual intake pressure and the actual intake pressure change rate, performs a corresponding post-processing step according to the severity level of the intake manifold leakage, avoids excessive engine speed fluctuation, and avoids engine stalling or rapid speed overshoot, so as to ensure that the vehicle can limp to a safe position when the intake manifold leaks.

[0065] Additional aspects and advantages of the present application will be made apparent by the following description and the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0066] The above and / or additional aspects and advantages of the present application will become apparent and be readily appreciated from the following description, including the accompanying drawings.

[0067] Figure 1 is a flow chart of the intake manifold leakage detection and post-processing method of the present application;

[0068] Figure 2 is a schematic diagram of the intake manifold leakage detection and post-processing device of the present application. DETAILED DESCRIPTION

[0069] The application will be further described below in conjunction with the drawings and embodiments. It should be understood that the specific embodiments described herein are intended to be merely illustrative of the application and not in limitation thereof. It should also be noted that, for the purpose of description, only the parts related to the application are shown in the drawings rather than all the parts.

[0070] In the description of the present application, unless otherwise explicitly specified and limited, the terms "connected", "connected", "fixed" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0071] Those skilled in the art can understand that, unless otherwise specified, the singular forms "a", "an" and "the" used herein also include the plural forms. It should be further understood that the phrase "comprising" used in the specification of the present application means that the features, integers, steps, operations, elements and / or components exist, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0072] Those skilled in the art can understand that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as that generally understood by those skilled in the art to which the present application belongs. It should also be understood that terms such as those defined in general dictionaries should be understood as having meanings consistent with those in the prior art, and unless specifically defined as in the embodiments of the present application, they should not be interpreted in an idealized or overly formal sense.

[0073] The present embodiment provides an intake manifold leakage detection and post-processing method, which is applied to engine intake manifold detection.

[0074] The flow chart of the intake manifold leakage detection and post-processing method provided by the present embodiment is shown in Figure 1 , which includes steps S10-S30.

[0075] S10, determining a pressure difference between the target intake pressure and the actual intake pressure and a rate of change of the actual intake pressure according to the target intake pressure of the engine and the actual intake pressure of the engine.

[0076] The intake pressure refers to the gas pressure in the intake manifold. The target intake pressure refers to a target value of the gas pressure in the intake manifold, and is an important parameter for controlling the target intake amount. The actual intake pressure refers to an actual value of the gas pressure in the intake manifold.

[0077] As a feasible implementation, the target intake pressure is determined according to the engine operating parameters, based on the ideal gas state equation, and by using the Newton-Raphson iteration method.

[0078] Further, in the embodiment, the actual intake pressure of the engine is detected by a pressure sensor at the outlet of the throttle valve.

[0079] The calculation formula of the pressure difference between the target intake pressure and the actual intake pressure is as follows:

[0080] P Diff =P Dsrd -P Act ;

[0081] P Diff , P Dsrd , and P Act .

[0082] It can be understood that when the intake manifold leaks, the more serious the leakage, the closer the actual intake pressure detected by the pressure sensor to the atmospheric pressure.

[0083] S20, determining a severity level of the intake manifold leakage according to the pressure difference and the rate of change of the actual intake pressure.

[0084] S30, performing corresponding post-processing steps for the intake manifold leakage according to the severity level, wherein the post-processing steps for the intake manifold leakage are used to control the engine speed fluctuation.

[0085] In the embodiment, the severity level of the intake manifold leakage is divided into a first level L1, a second level L1, and a third level L1.

[0086] In one embodiment, in each intake manifold leakage detection, it is first determined whether the current situation meets the first level L1 of the severity level, and if so, the post-processing step corresponding to the first level L1 of the severity level is performed.

[0087] Specifically, the step of determining whether the current situation meets the first level L1 of the severity level includes S201-S202.

[0088] S201. When the pressure difference is greater than the first pressure difference threshold and the actual intake pressure change rate is less than or equal to the first change threshold, the engine is determined to be in the first state.

[0089] The first differential pressure threshold is:

[0090] A1 = P Dsrd ·k1+c1;

[0091] Where A1 is the first differential pressure threshold, P Dsrd Let k1 be the target intake pressure, c1 be the first differential pressure coefficient, and c1 be the first compensation coefficient. In this embodiment, the first differential pressure coefficient k1 is determined based on the engine speed and atmospheric pressure. The first compensation coefficient c1 is determined based on the target boost pressure and atmospheric pressure.

[0092] Furthermore, the first pressure difference coefficient k1 is related to the engine speed n and atmospheric pressure P. Amb The relationships are shown in Table 1.

[0093]

[0094] Table 1

[0095] During vehicle operation, atmospheric pressure is detected by a pressure sensor at the throttle outlet. It can be understood that the atmospheric pressure P varies at different altitudes. Amb The values ​​will vary.

[0096] Furthermore, the step of determining the first compensation coefficient c1 based on the target boost pressure and atmospheric pressure includes: when the difference between the target boost pressure and atmospheric pressure is greater than the fourth pressure difference threshold, the value of the first compensation coefficient c1 is -3 kPa; when the difference between the target boost pressure and atmospheric pressure is less than or equal to the fourth pressure difference threshold, the value of the first compensation coefficient c1 is 0 kPa.

[0097] As a feasible implementation method, the target boost pressure is determined based on the target intake pressure. Technicians experimentally determine a fourth pressure difference threshold. In this embodiment, the fourth pressure difference threshold is set to 5 kPa, meaning that: when the difference between the target boost pressure and atmospheric pressure is greater than 5 kPa, the first compensation coefficient c1 is set to -3 kPa; when the difference between the target boost pressure and atmospheric pressure is less than or equal to 5 kPa, the first compensation coefficient c1 is set to 0 kPa.

[0098] In this embodiment, technicians determined the first change threshold through experimental calibration, and the value of the first change threshold is 10 kPa / s.

[0099] S202. When the cumulative time the engine is in the first state is greater than the first preset time, the severity level is determined to be Level 1 L1.

[0100] In this embodiment, the first preset time is 1.2s.

[0101] It is understandable that, based on the calculation formula for the first differential pressure threshold, the first differential pressure threshold A1 is always greater than 0 kPa. Therefore, when the severity level of the intake manifold leakage is Level 1 (L1), the target intake pressure is greater than the actual intake pressure. At this time, the engine's power demand is high, but the actual power response is insufficient and fails to meet the engine's power requirements.

[0102] When the severity level is Level 1 (L1), in order to reduce engine speed fluctuations, prevent engine stalling, and ensure that the vehicle can limp to a safe position, the following post-processing steps should be performed:

[0103] Throttle effective area self-learning is disabled. Throttle effective area self-learning dynamically adjusts the throttle effective area under different operating conditions using a PI control system, thereby improving the stability and accuracy of the engine's intake system. Under steady-state conditions, the throttle state is relatively stable, and the gas flow rates at the throttle inlet and outlet are stable and equal. However, in the case of intake manifold leakage, the gas flow rate at the throttle outlet does not represent the gas flow rate entering the cylinder. Therefore, the throttle effective area determined by throttle effective area self-learning is inaccurate, and deviations in gas flow control can cause unstable power. Therefore, in the case of intake manifold leakage, throttle effective area self-learning is disabled to improve engine stability.

[0104] Activation of the carbon canister control is prohibited. When the exhaust port solenoid valve of the carbon canister opens, the fuel adsorbed in the carbon canister is desorbed under the negative pressure of the engine and drawn into the engine for combustion. This process exacerbates engine vibration. Therefore, to improve engine stability, activation of the carbon canister control should be prohibited when there is an intake manifold leak.

[0105] Engine fuel cut-off command triggering is prohibited. When the fuel cut-off command is triggered, the engine will interrupt fuel injection. This action is not allowed to interrupt fuel injection. Because at severity level L1, the engine's actual power response is insufficient, if the fuel cut-off command is triggered at this time, it may cause the engine to stall. Therefore, engine fuel cut-off command triggering must be prohibited.

[0106] Adjust the minimum allowable air volume for engine operation:

[0107] rho Min =k(n, P) Dsrd )·rho MinRaw ;

[0108] Among them, rho Min The minimum allowable gas volume for the modified engine operation, k(n, P) Dsrd ) represents the correction factor determined based on engine speed and target intake pressure, rho MinRawThe minimum air amount allowed for the engine to run before the correction.

[0109] The correction coefficient k(n, P Dsrd ) is related to the engine speed n and the target intake air pressure P Dsrd . See Table 2.

[0110]

[0111] Table 2

[0112] Correct the engine idle target speed:

[0113] n IdleDsrd ' = max(n IdleDsrd (T, P Amb ), n IdleDsrdRaw );

[0114] wherein n IdleDsrd ' is the corrected idle target speed, n IdleDsrd (T, P Amb ) is the idle target speed determined according to the engine water temperature and the atmospheric pressure, and n IdleDsrdRaw is the idle target speed under normal control.

[0115] The idle target speed n IdleDsrd (T, P Amb ) is related to the engine water temperature T and the atmospheric pressure P Amb . The data in Table 3 are determined by technicians through experiments, and under different altitudes and different engine combustion performances, the idle target speed n IdleDsrd (T, P Amb ) ensures that the engine does not stall.

[0116]

[0117] Table 3

[0118] It can be understood that the idle target speed n IdleDsrdRaw under normal control refers to the idle target speed when there is no intake manifold leakage.

[0119] As a feasible implementation, when the severity level of the detected intake manifold leakage is the first level L1, the above five post-processing steps are simultaneously performed to reduce the engine speed fluctuation (so that the engine speed fluctuation does not exceed ±80 rpm) and avoid engine stall.

[0120] In an embodiment, in each intake manifold leakage detection, when the current situation does not meet the severity level of the first level L1, it is determined whether the current situation meets the severity level of the second level L2, and if so, the post-processing step corresponding to the severity level of the second level L2 is performed.

[0121] Specifically, the step of determining whether the current situation meets the second severity level L2 includes S203-S204.

[0122] S203, when the pressure difference is less than the second pressure difference threshold and the actual intake air pressure change rate is greater than or equal to the second change threshold, determining that the engine is in the second state.

[0123] Wherein, the second pressure difference threshold is:

[0124] A2 = -(P Dsrd ·k2+c2);

[0125] Wherein, A2 is the second pressure difference threshold, k2 is the second pressure difference coefficient, and c2 is the second compensation coefficient. In this embodiment, the second pressure difference coefficient k2 is determined according to the engine speed and the atmospheric pressure. The second compensation coefficient c2 is determined according to the target boost pressure and the atmospheric pressure.

[0126] Further, the second pressure difference coefficient k2 has a relationship with the engine speed and the atmospheric pressure P Amb See Table 4.

[0127] Further, the step of determining the second compensation coefficient c2 according to the target boost pressure and the atmospheric pressure includes: when the difference between the target boost pressure and the atmospheric pressure is greater than the fifth pressure difference threshold, the value of the second compensation coefficient c2 is 1 kPa; when the difference between the target boost pressure and the atmospheric pressure is less than or equal to the fifth pressure difference threshold, the value of the second compensation coefficient c2 is 4 kPa.

[0128] As a feasible implementation manner, the target boost pressure is determined according to the target intake air pressure. The fifth pressure difference threshold is determined by the technician through experiment. In this embodiment, the value of the fifth pressure difference threshold is 2 kPa, that is: when the difference between the target boost pressure and the atmospheric pressure is greater than 2 kPa, the value of the second compensation coefficient c2 is 1 kPa; when the difference between the target boost pressure and the atmospheric pressure is less than or equal to 2 kPa, the value of the second compensation coefficient c2 is 4 kPa.

[0129]

[0130] Table 4

[0131] In this embodiment, the technician determines the second change threshold through experiment calibration, and the value of the second change threshold is -8 kPa / s.

[0132] S204, when the cumulative time of the engine in the second state is greater than the second preset time, determining that the severity level is the second level L2.

[0133] In this embodiment, the second preset time is 1.2 s.

[0134] It can be understood that the second pressure difference threshold A2 is always less than 0 kPa according to the calculation formula of the second pressure difference threshold, and when the severity level of the intake manifold leakage is the second level L2, the target intake pressure is less than the actual intake pressure, at this time, the power demand of the engine is small, but the actual power is large.

[0135] When the severity level is the second level L2, in order to avoid the engine speed from continuously rising and the speed jitter being serious, and at the same time to reduce the engine speed fluctuation, ensure that the vehicle can limp to a safe position, the following post-processing steps are executed:

[0136] The throttle effective area self-learning is closed. The throttle effective area self-learning is to correct the throttle effective area through PI dynamic adjustment under different working conditions, so as to improve the stability and accuracy of the engine intake system. In the steady state condition, the state of the throttle is relatively stable, and the gas flow at the inlet and outlet of the throttle is stable and equal. However, in the case of intake manifold leakage, the gas flow at the outlet of the throttle cannot represent the gas flow into the cylinder, therefore, the throttle effective area determined through the throttle effective area self-learning is inaccurate, and the deviation of the gas control will cause power instability. Therefore, when the intake manifold leaks, the engine stability is improved by closing the throttle effective area self-learning.

[0137] The carbon can control activation is prohibited. When the exhaust port electromagnetic valve of the carbon can is opened, the fuel adsorbed by the carbon can is desorbed and sucked into the engine for combustion under the action of engine negative pressure, and this process will exacerbate the engine jitter. Therefore, when the intake manifold leaks, the carbon can control activation is prohibited to improve the stability of the engine.

[0138] During the engine working cycle, the engine cylinders are controlled to be cut off in accordance with the ignition order, wherein the cylinder to be ignited in the current working cycle is controlled to be cut off. Through the cycle cut-off control, the engine speed is avoided to be too high, and at the same time, only one engine cylinder is cut off in each working cycle, which can effectively avoid the abnormal jitter of the engine during cut-off.

[0139] For example, in a four-cylinder engine, the engine is ignited in the order of the first cylinder, the third cylinder, the fourth cylinder, and the second cylinder. When the severity level of the intake manifold leakage is detected to be the second level L2, the cylinder to be ignited next is read. If the cylinder to be ignited next is the fourth cylinder, then in the current working cycle, the fourth cylinder is controlled to be cut off, and in the next working cycle, the second cylinder is controlled to be cut off according to the ignition order, and so on, in the subsequent working cycles, the cylinders of the engine are controlled to be cut off in turn according to the ignition order. Only one cylinder is controlled to be cut off in each working cycle, and the other cylinders are not allowed to be cut off. The working cycle of the engine includes four processes, intake, compression, work, and exhaust, simply, the engine completes the four working processes of intake, compression, work, and exhaust in one working cycle, if a certain cylinder is in the intake stroke, the other cylinders are in the compression stroke, the work stroke, and the exhaust stroke respectively. The injection and ignition actions are completed in the compression stroke.

[0140] The maximum engine speed is limited, wherein the maximum engine speed is determined according to the throttle opening and the atmospheric pressure. The maximum engine speed n Max The relationship between the throttle opening, the atmospheric pressure P Amb , and the maximum engine speed is shown in Table 5.

[0141]

[0142] Table 5

[0143] The target air-fuel ratio is corrected:

[0144] AFR = k(n, P Diff )·AFR Raw ;

[0145] wherein AFR is the corrected target air-fuel ratio, k(n, P Diff ) is a correction coefficient determined according to the engine speed and the pressure difference, and AFR Raw is the target air-fuel ratio before correction.

[0146] The relationship between the correction coefficient k(n, P Diff ) and the engine speed n and the pressure difference P Diff is shown in Table 6.

[0147] In the second level L2, the target air-fuel ratio is corrected according to the engine speed and the pressure difference, as shown in Table 6, the value of the correction coefficient k(n, P Diff ) is greater than or equal to 1, and the corrected target air-fuel ratio AFR is greater than or equal to the target air-fuel ratio AFR Raw before correction. It can be seen that after correction, the mass fraction of air in the air-fuel mixture increases, and the fuel gas is diluted, so as to avoid the engine speed surge.

[0148]

[0149] Table 6

[0150] As a feasible implementation, when the severity level of the intake manifold leakage detection is the second level L2, the above five post-processing steps are simultaneously performed to reduce the engine speed fluctuation size (so that the engine speed fluctuation does not exceed ±80rpm) and avoid the engine speed from continuously rising.

[0151] In an embodiment, in each intake manifold leakage detection, when the current situation does not meet the severity level of the second level L1 and the current situation does not meet the severity level of the second level L2, it is determined whether the current situation meets the severity level of the third level L3, and if so, the post-processing step corresponding to the severity level of the third level L3 is performed.

[0152] Specifically, the step of determining whether the current situation meets the severity level of the third level L3 includes S205-S206.

[0153] S205, when the pressure difference is greater than or equal to the third pressure difference threshold and the pressure difference is less than or equal to the first pressure difference threshold, it is determined that the engine is in the third state.

[0154] Wherein, the third pressure difference threshold is:

[0155] A3 = P Dsrd · k2 + c2;

[0156] Wherein, A3 is the third pressure difference threshold.

[0157] In this embodiment, the engine is in the third state also needs to meet: the pressure difference P Diff exceeds the control accuracy requirement, for example, when the control accuracy requirement is:

[0158] -2 kPa ≤ P Diff ≤ 2 kPa;

[0159] When the engine is in the third state, the pressure difference P Diff is greater than 2 kPa or the pressure difference P Diff is less than -2 kPa.

[0160] S206, when the cumulative time of the engine in the third state is greater than the third preset time, it is determined that the severity level is the third level L3.

[0161] When the severity level of the intake manifold leakage meets the first level L1 or the second level L2, the intake manifold is in a large leakage state, and the corresponding post-processing step is aggressive. The judgment time is too short, and misjudgment may occur. When the severity level is the third level L3, the severity level of the intake manifold leakage does not meet the first level L1 and the second level L2, and the intake manifold is in a small leakage state. The corresponding post-processing step is relatively mild, and early intervention can better improve the engine speed fluctuation. Therefore, in the design parameters in the embodiment, the third preset time is less than the first preset time and the third preset time is less than the second preset time.

[0162] In the embodiment, the third preset time is 0.8s.

[0163] When the severity level is the third level L3, the following post-processing steps are performed:

[0164] The throttle effective area self-learning is closed. The throttle effective area self-learning is to correct the throttle effective area through PI dynamic adjustment under different working conditions, so as to improve the stability and precision of the engine intake system. In the steady state condition, the state of the throttle is relatively stable, and the gas flow at the inlet and outlet of the throttle is stable and equal. However, in the case of intake manifold leakage, the gas flow at the outlet of the throttle cannot represent the gas flow into the cylinder, and therefore the throttle effective area determined through the throttle effective area self-learning is inaccurate, and the deviation of the gas quantity control will cause unstable power. Therefore, when the intake manifold leaks, the engine stability is improved by closing the throttle effective area self-learning.

[0165] The carbon can control activation is prohibited. When the exhaust port electromagnetic valve of the carbon can is opened, the fuel adsorbed by the carbon can is desorbed and sucked into the engine for combustion under the action of engine negative pressure, which will exacerbate the engine vibration. Therefore, when the intake manifold leaks, the carbon can control activation is prohibited to improve the stability of the engine.

[0166] The maximum engine speed is limited, wherein the maximum engine speed is determined according to the throttle opening and the atmospheric pressure. The maximum engine speed n Max and the atmospheric pressure P Amb Continue to refer to Table 5.

[0167] The idle target speed is optimized:

[0168] n IdleDsrd ″=n IdleDsrdRaw +P DiddFilt ·(n IdleAct -n IdleDsrdRaw );

[0169] Wherein, n IdleDsrd ″ is the optimized idle target speed, P DiddFilt is the filtered value of the pressure difference of the intake pressure, nIdleAct is the engine speed at idle.

[0170] Further, the filtered value P DiddFilt of the differential pressure is calculated according to the following formula:

[0171] P DiddFilt (m) = P DiddFilt (m-1) + k Filt · (P Diff - P DiddFilt (m-1));

[0172] wherein m = 1, 2, 3,... P DiddFilt (m) is the filtered value of the differential pressure at the mth cycle, P DiddFilt (m-1) is the filtered value of the differential pressure at the (m-1)th cycle, k Filt is the filtering coefficient.

[0173] In this embodiment, the sampling cycle is 10 ms.

[0174] Further, when the engine is in the third state for a cumulative time equal to the third preset time, and the differential pressure is P Diff (0), then:

[0175] P DiddFilt (0) = P Diff (0).

[0176] As a feasible implementation, when the detected severity level of the intake manifold leak is the third level L3, the above four post-processing steps are simultaneously performed to improve the engine speed fluctuation through the sampling closed-loop control.

[0177] In each intake manifold leak detection, when the current situation does not meet any severity level, it is determined that there is no intake manifold leak, and no post-processing step is performed.

[0178] It can be understood that during driving, the vehicle continuously performs the above intake manifold leak detection, and if the intake manifold leak occurs (i.e., the current situation meets the first severity level L1, or the current situation meets the second severity level L2, or the current situation meets the third severity level L3), the corresponding post-processing step is performed.

[0179] The intake manifold leakage detection and post-processing method in the embodiment determines the pressure difference between the target intake pressure and the actual intake pressure and the actual intake pressure change rate according to the target intake pressure of the engine and the actual intake pressure of the engine, determines the severity level of the intake manifold leakage according to the pressure difference and the actual intake pressure change rate, and executes corresponding intake manifold leakage post-processing steps according to the severity level, wherein the intake manifold leakage post-processing steps are used to control the engine speed fluctuation. The application determines whether the intake manifold leaks according to the pressure difference between the target intake pressure and the actual intake pressure and the actual intake pressure change rate, executes corresponding post-processing steps according to the severity level of the intake manifold leakage, avoids excessive engine speed fluctuation, and avoids engine stall or rapid speed surge, so as to ensure that the vehicle can limp to a safe position when the intake manifold leaks.

[0180] The embodiment also provides an intake manifold leakage detection and post-processing device, Figure 2 FIG. 1 is a schematic diagram of an intake manifold leakage detection and post-processing device provided by the embodiment.

[0181] Referring to Figure 2 The intake manifold leakage detection and post-processing device comprises a first module 21, a second module 22 and a third module 23.

[0182] The first module 21 is used to determine the pressure difference between the target intake pressure and the actual intake pressure and the actual intake pressure change rate according to the target intake pressure of the engine and the actual intake pressure of the engine.

[0183] The second module 22 is used to determine the severity level of the intake manifold leakage according to the pressure difference and the actual intake pressure change rate.

[0184] The third module 23 is used to execute corresponding intake manifold leakage post-processing steps according to the severity level.

[0185] It should be noted that the intake manifold leakage detection and post-processing device provided by the embodiment can be a computer program (including program code) running in a computer device, for example, the intake manifold leakage detection and post-processing device as an application program can be used to execute the corresponding steps in the intake manifold leakage detection and post-processing method provided by the embodiment.

[0186] In some possible implementation manners, the intake manifold leakage detection and post-processing device provided by the embodiment can be realized in a combination of software and hardware, and can also be realized in a software manner, which can be a program and a plug-in and the like in the form of software, and comprises a series of modules.

[0187] The embodiment also provides an electronic device, comprising 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 intake manifold leakage detection and post-processing method when executing the computer program.

[0188] The embodiment also provides a computer readable storage medium, which stores computer instructions, and makes a computer execute the steps of the intake manifold leakage detection and post-processing method.

[0189] It should be understood that, although each step in the flowchart of the accompanying drawings is displayed in sequence according to the indication of the arrow, these steps are not necessarily executed in sequence according to the indication of the arrow. Unless explicitly stated herein, the execution of these steps is not strictly limited in sequence, and they can be executed in other sequences. Moreover, at least part of the steps in the flowchart of the accompanying drawings can comprise multiple sub-steps or multiple stages, which are not necessarily executed at the same time, but can be executed at different times, and the execution sequence is not necessarily sequential, but can be executed in rotation or alternation with at least part of other steps or sub-steps or stages of other steps.

[0190] The above only describes some embodiments of the present application, and it should be pointed out that, for those skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present application.

Claims

1. A method of intake manifold leak detection and aftertreatment, characterized by, The method comprises the following steps: determining a pressure difference between the target intake pressure and the actual intake pressure and an actual intake pressure change rate according to the target intake pressure and the actual intake pressure of the engine; determining a severity level of intake manifold leakage according to the pressure difference and the actual intake pressure change rate; performing corresponding intake manifold leakage post-processing steps according to the severity level, the intake manifold leakage post-processing steps being used to control engine speed fluctuation; the step of determining the severity level of intake manifold leakage according to the pressure difference and the actual intake pressure change rate comprises: determining that the engine is in a first state when the pressure difference is greater than a first pressure difference threshold and the actual intake pressure change rate is less than or equal to a first change threshold; determining that the severity level is a first level L1 when a cumulative time of the engine being in the first state is greater than a first preset time; wherein the first pressure difference threshold is: ； wherein is a first pressure difference threshold value, is a target intake air pressure, is a first pressure difference coefficient, is a first compensation coefficient; the step of performing intake manifold leakage post-processing according to the severity level comprises: When the severity level is the first level the following post-processing steps are performed: turning off throttle effective area self-learning; inhibiting carbon canister control activation; inhibiting engine fuel cut instruction triggering; correcting a minimum air amount allowed for engine operation: ； wherein is the minimum air amount allowed for the engine to operate after correction, is a correction coefficient determined in accordance with the engine speed and the target intake air pressure, is the minimum air amount allowed for the engine to operate before correction; correcting an engine idle target speed: ； wherein, is the corrected idle target speed, is the idle target speed determined in accordance with the engine water temperature and the atmospheric pressure, is the idle target speed under normal control.

2. The air intake manifold leak detection and post-processing method of claim 1, wherein, the step of determining the severity level of intake manifold leakage according to the pressure difference and the actual intake pressure change rate further comprises: determining that the engine is in a second state when the pressure difference is less than a second pressure difference threshold and the actual intake pressure change rate is greater than or equal to a second change threshold; determining that the severity level is a second level when the cumulative time that the engine is in the second state is greater than a second preset time ; wherein the second pressure difference threshold is: ； wherein is a second differential pressure threshold, is a second differential pressure coefficient, is a second compensation coefficient.

3. The air intake manifold leak detection and post-processing method of claim 2, wherein, the step of performing intake manifold leakage post-processing according to the severity level further comprises: When the severity level is a second level the following post-processing steps are performed: turning off throttle effective area self-learning; inhibiting carbon canister control activation; in the process of engine working cycle, performing cycle fuel cut control on each cylinder of the engine according to the ignition order, wherein the fuel cut control is performed on the cylinder to be ignited in the current working cycle; limiting the maximum engine speed, wherein the maximum engine speed is determined according to the throttle opening degree and the atmospheric pressure; correcting the target air-fuel ratio: ； wherein A is the target air-fuel ratio after correction, A is a correction coefficient determined in accordance with the engine speed and the pressure difference, A is the target air-fuel ratio before correction.

4. The air intake manifold leak detection and post-processing method of claim 1, wherein, the step of determining the severity level of intake manifold leakage according to the pressure difference and the actual intake pressure change rate further comprises: determining that the engine is in a third state when the pressure difference is greater than or equal to a third pressure difference threshold and the pressure difference is less than or equal to the first pressure difference threshold; determining that the severity level is a third level when the cumulative time of the engine in the third state is greater than a third preset time ; wherein the third pressure difference threshold is: ； wherein is a third differential pressure threshold is a second differential pressure coefficient, is a second compensation coefficient.

5. The air intake manifold leak detection and post-processing method of claim 4, wherein, the step of performing intake manifold leakage post-processing according to the severity level further comprises: When the severity level is third level the following post-processing steps are performed: turning off throttle effective area self-learning; inhibiting carbon canister control activation; limiting the maximum engine speed, wherein the maximum engine speed is determined according to the throttle opening degree and the atmospheric pressure; optimizing the idle target speed: ； wherein, is the optimized idle target speed, is the filtered value of the pressure difference, is the engine speed at idle.

6. An intake manifold leak detection and post-processing apparatus characterized by, comprises: a first module for determining a pressure difference between the target intake pressure and the actual intake pressure and an actual intake pressure change rate according to the target intake pressure and the actual intake pressure of the engine; a second module for determining a severity level of intake manifold leakage according to the pressure difference and the actual intake pressure change rate; a third module for performing corresponding intake manifold leakage post-processing steps according to the severity level; The step of determining a severity level of the intake manifold leak according to the pressure difference and the actual intake pressure change rate comprises: determining that the engine is in a first state when the pressure difference is greater than a first pressure difference threshold and the actual intake pressure change rate is less than or equal to a first change threshold; determining that the severity level is a first level L1 when a cumulative time of the engine in the first state is greater than a first preset time; wherein the first pressure difference threshold is: ； wherein is a first pressure difference threshold value, is a target intake air pressure, is a first pressure difference coefficient, is a first compensation coefficient; The step of performing post-processing of the intake manifold leak according to the severity level comprises: When the severity level is the first level the following post-processing steps are performed: closing the throttle effective area self-learning; inhibiting carbon canister control activation; inhibiting engine fuel cut command triggering; correcting the minimum air amount for engine operation: ； wherein is the minimum air amount for which the engine is allowed to operate after correction, is a correction coefficient determined in accordance with the engine speed and the target intake air pressure, is the minimum air amount for which the engine is allowed to operate before correction; correcting the engine idle target speed: ； wherein, is the corrected idle target speed, is the idle target speed determined in accordance with the engine water temperature and the atmospheric pressure, is the idle target speed under normal control.

7. A gas intake manifold leak detection and post-processing apparatus according to claim 6, wherein, The step of determining a severity level of the intake manifold leak according to the pressure difference and the actual intake pressure change rate further comprises: determining that the engine is in a second state when the pressure difference is less than a second pressure difference threshold and the actual intake pressure change rate is greater than or equal to a second change threshold; determining that the severity level is a second level when the cumulative time that the engine is in the second state is greater than a second preset time ; wherein the second pressure difference threshold is: ； wherein is a second differential pressure threshold, is a second differential pressure coefficient, is a second compensation coefficient.

8. A gas intake manifold leak detection and post-processing apparatus according to claim 7, wherein, The step of performing post-processing of the intake manifold leak according to the severity level further comprises: When the severity level is a second level the following post-processing steps are performed: closing the throttle effective area self-learning; inhibiting carbon canister control activation; during the engine working cycle, performing cycle fuel cut control on each cylinder of the engine according to the ignition order, wherein the cycle fuel cut control is performed on the cylinder to be ignited in the current working cycle; limiting the maximum engine speed, wherein the maximum engine speed is determined according to the throttle opening and the atmospheric pressure; correcting the target air-fuel ratio: ； wherein, A is the target air-fuel ratio after correction, B is a correction coefficient determined in accordance with the engine speed and the pressure difference, A is the target air-fuel ratio before correction.

9. An electronic device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor executes the computer program to implement the steps of the intake manifold leak detection and post-processing method according to any one of claims 1 to 5.

10. A computer-readable storage medium, characterized in that, The computer readable storage medium stores computer instructions, which cause the computer to execute the steps of the intake manifold leak detection and post-processing method according to any one of claims 1 to 5.

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