Exhaust Manifold Pressure Sensor Ice Blockage Fault Diagnosis Method

Abstract

The present invention relates to a method for diagnosing the icing and blockage fault of an exhaust manifold pressure sensor, which includes the steps of: collecting pressure signals; calculating the exhaust pulse period; calculating the characteristic value of the exhaust manifold pressure signal; and confirming the fault diagnosis window and fault status. The present invention meets the requirements of rapid warm-up for quickly identifying, real-time monitoring, and accurately judging the icing and blockage fault of the exhaust pressure sensor; makes up for the defects that electrical diagnosis and rationality diagnosis cannot or cannot timely diagnose the icing fault of the P3 sensor; provides a diagnosis method for the icing fault of the exhaust manifold pressure sensor; can detect the fault immediately after the engine starts, and quickly eliminate the untrustworthy condition of the exhaust manifold sensor pressure signal caused by icing.

Description

Technical Field

[0001] The present invention relates to the technical field of engines, and particularly to a method for diagnosing the icing and blockage fault of an exhaust manifold pressure sensor. Background Art

[0002] When the engine starts in a low-temperature environment, in order to accelerate the warm-up speed, it is necessary to adjust the exhaust back pressure to achieve the rapid warm-up function. The exhaust adjustment takes the difference between the required value and the actual value of the exhaust manifold pressure (P3) as the input. When the sensor signal is not credible, its closed-loop control strategy should fail. At low temperatures, the water vapor in the exhaust manifold may freeze and cause the intake pipe of the sensor to be blocked. Therefore, it is necessary to monitor the state of the P3 pressure sensor to ensure the accuracy and credibility of its signal, so as to judge whether the current state of the engine can perform exhaust pressure adjustment.

[0003] To solve the above problems, there are generally two types of existing technologies:

[0004] The first type of existing technology is typically represented by the Chinese invention application with the application number CN202011176334.6 and the title "A Method, Device, Equipment and Storage Medium for Fault Diagnosis of an Intake Pressure Sensor", which discloses the following technical features:

[0005] 1. The intake pressure sensor is arranged on the intake manifold, including: obtaining the engine speed and the voltage value collected by the intake pressure sensor; if the absolute value of the difference between adjacent engine speeds collected within the first preset time is greater than the first difference threshold, the engine speed is within the first set range, and the absolute value of the difference between adjacent voltages collected within the second preset time is less than the second difference threshold, then it is determined that the intake pressure sensor has a sticking fault.

[0006] 2. After determining that the intake pressure sensor has a sticking fault if the absolute value of the difference between adjacent engine speeds collected within the first preset time is greater than the first difference threshold, the engine speed is within the set range, and the absolute value of the difference between adjacent voltages collected within the second preset time is less than the second difference threshold, it further includes: calculating the intake air volume of the engine according to the secondary charging model, and determining the fuel injection volume according to the intake air volume.

[0007] 3. After calculating the intake air volume of the engine through the secondary charging model and determining the fuel injection volume according to the intake air volume, it further includes: if the absolute value of the difference between adjacent engine speeds collected within the third preset time is greater than the third difference threshold, the engine speed is within the second set range, and the absolute value of the difference between adjacent voltages collected within the fourth preset time is greater than or equal to the fourth difference threshold, it is determined that the sticky fault of the intake pressure sensor is repaired, where the second set range includes the first set range, the third preset time is greater than the first preset time, the fourth preset time is greater than the second preset time, the third difference threshold is greater than the first difference threshold, and the fourth difference threshold is less than the second difference threshold; after the fifth preset time, calculate the intake air volume of the engine according to the main charging model and determine the fuel injection volume according to the intake air volume.

[0008] 4. Calculating the intake air volume of the engine according to the main charging model and determining the fuel injection volume according to the intake air volume includes: inputting the voltage value collected by the intake pressure sensor into the main charging model, calculating the intake air volume of the engine, and determining the fuel injection volume according to the intake air volume.

[0009] 5. Calculating the intake air volume of the engine according to the secondary charging model and determining the fuel injection volume according to the intake air volume includes: inputting the throttle opening and the air flow pressure ratio before and after the throttle into the secondary charging model, calculating the intake air volume of the engine, and determining the fuel injection volume according to the intake air volume.

[0010] 6. It includes: an acquisition module for acquiring the engine speed and the voltage value collected by the intake pressure sensor; a first determination module for determining the sticky fault of the intake pressure sensor if the absolute value of the difference between adjacent engine speeds collected within the first preset time is greater than the first difference threshold, the engine speed is within the first set range, and the absolute value of the difference between adjacent voltages collected within the second preset time is less than the second difference threshold.

[0011] 7. The device further includes: a first calculation module for, after determining the sticky fault of the intake pressure sensor, calculating the intake air volume of the engine according to the secondary charging model and determining the fuel injection volume according to the intake air volume.

[0012] 8. The device further includes: a second determination module for determining that the sticky fault of the intake pressure sensor is repaired if the absolute value of the difference between adjacent engine speeds collected within the third preset time is greater than the third difference threshold, the engine speed is within the second set range, and the absolute value of the difference between adjacent voltages collected within the fourth preset time is greater than the fourth difference threshold, where the second set range includes the first set range, the third preset time is greater than the first preset time, the fourth preset time is greater than the second preset time, the third difference threshold is greater than the first difference threshold, and the fourth difference threshold is less than the second difference threshold; a second calculation module for, after the fifth preset time, calculating the intake air volume of the engine according to the main charging model and determining the fuel injection volume according to the intake air volume.

[0013] The principle of the first prior art is as follows: By obtaining the engine speed and the voltage value collected by the intake pressure sensor, when the absolute value of the difference between adjacent engine speeds collected within the first preset time is greater than the threshold, and the absolute value of the difference between adjacent voltages collected within the second preset time is less than the threshold, it is determined that there is a sticking fault in the intake pressure sensor.

[0014] A typical example of the second prior art is the Chinese invention application with the application number CN202080095121.2 and the title "Method for automatically detecting blockage of a sensor pipe extending between an exhaust manifold and a pressure sensor of an internal combustion engine", which discloses the following technical features:

[0015] 1. The method includes at least one of the following steps: a) While the engine is running in a stable operating state, determine the average amplitude of the oscillation of the signal within the first time period (T1). When the average amplitude is less than the first threshold, the sensor pipe (16) is considered blocked; b) Starting from the time when the engine (10) has been turned off, monitor the signal within the second time period (T2). When the integral of the signal within the second time period (T2) is greater than the second threshold, the sensor pipe (16) is considered blocked.

[0016] 2. The first time period (T1) is between 5 s and 10 s. The second threshold varies depending on the exhaust pressure when the engine is cut off. The first threshold varies depending on the operating point of the engine. The first threshold is a percentage of the expected normal average amplitude that can be derived from a theoretical model or experiment, usually 50%. The second threshold is a percentage of the expected normal pressure integral, usually 50%. The second time period corresponds to the time period between the time when the engine is cut off and the time when the electronic control unit (ECU) of the engine is cut off, and the second time period is between 1 s and 10 s.

[0017] 3. When it is detected that the sensor pipe (16) is blocked, a signal is sent to the driver, and the signal is a light displayed on the vehicle instrument panel. As long as the electronic control unit (ECU) of the engine (10) is turned on, the steps of the method are repeatedly implemented. The first time period (T1) is selected to be more than at least two consecutive combustion stages of the ignition cycle, preferably three consecutive combustion stages.

[0018] 4. The first time period (T1) is set to be equal to the time taken for the engine crankshaft to reach a specific crank angle degree, and the crank angle degree is inherent to the number of cylinders of the engine. For a 4-cylinder application, the specific crank angle degree is equal to 22.5°, and for a 6-cylinder application, the specific crank angle degree is equal to 15°.

[0019] 5. Comprising a preparatory step, the preparatory step comprising: monitoring one or more operating parameters of the engine, such as i) engine speed and torque or ii) fuel consumption; and checking whether the one or more operating parameters are stable before performing step a), i.e., whether a stable operating state has been reached.

[0020] 6. An internal combustion engine assembly (10), comprising an exhaust manifold (12), a pressure sensor (14), and a sensor conduit (16) extending between the exhaust manifold and the pressure sensor, characterized in that the engine assembly further comprises an electronic control unit (ECU) for detecting a blockage of the sensor conduit (16) using the method according to any one of the preceding claims. The internal combustion engine assembly is a four-stroke engine. A wired or wireless device connects the electronic control unit (ECU) to the pressure sensor (14). The electronic control unit is configured to: receive one or more operating parameters of the engine, such as i) engine speed and torque or ii) fuel consumption; and process the received information to check whether the operating parameters are stable over time before performing step a) of the method, i.e., whether a stable operating state has been reached.

[0021] The principle of the second prior art is to obtain the exhaust back pressure ("raw" pressure) at regular intervals according to the CAD slot (crank angle degrees). When the engine is operating in a stable state, the average amplitude of the oscillation of the signal in the first time period is determined. When the average amplitude is less than the first threshold, the sensor conduit is considered blocked.

[0022] The deficiencies of the prior art are as follows:

[0023] The existing exhaust manifold pressure (P3) sensor diagnosis includes electrical diagnosis and rationality diagnosis, but neither can diagnose the P3 sensor blockage fault or can do so in a timely manner. When the vehicle is in a low-temperature environment, the pressure port of the sensor may freeze due to the water vapor in the exhaust manifold. When the engine starts, the exhaust manifold pressure (P3) sensor cannot accurately obtain the real-time exhaust pressure signal, and the ECU cannot identify the fault state of the exhaust pressure sensor. It may cause the exhaust brake valve to close excessively, resulting in engine stalling.

[0024] Compared with the pressure signal of the intake manifold, the exhaust manifold pressure signal fluctuates periodically and its change is more complex. Although the invention patent with the application number CN202011176334.6 is applicable to the exhaust manifold pressure sensor blockage fault, it needs to collect the rotational speed or sensor voltage signals in two time periods. At idle speed, the rotational speed fluctuation is small, and the actual state of the exhaust manifold pressure sensor cannot be identified.

[0025] The invention patent with the application number CN202011176334.6 obtains the exhaust back pressure every certain number of crank angle degrees, and the engine needs to be in a stable state for diagnosis. Its sampling samples are relatively few, and it takes a certain amount of time for the engine to reach a stable state. The original signals obtained are not processed, and distorted signals may cause false alarms of faults. Its detection result accuracy is not high, and the identification is not timely enough. Summary of the Invention

[0026] In view of the above problems, the present invention provides a method for diagnosing the icing and blockage fault of an exhaust manifold pressure sensor, aiming to meet the requirements of rapid warm-up for rapid identification, real-time monitoring, and accurate judgment of the icing and blockage fault of the exhaust pressure sensor; to make up for the defects that electrical diagnosis and rationality diagnosis cannot or cannot timely diagnose the icing fault of the P3 sensor; to provide a diagnosis method for the icing fault of the exhaust manifold pressure sensor; to detect the fault as soon as the engine starts, and quickly eliminate the untrustworthy condition of the exhaust manifold sensor pressure signal caused by icing.

[0027] To solve the above problems, the technical solution provided by the present invention is as follows:

[0028] A method for diagnosing the icing and blockage fault of an exhaust manifold pressure sensor includes the following steps:

[0029] S100. Collect pressure signals;

[0030] S200. Calculate the exhaust pulse period;

[0031] S300. Calculate the characteristic value of the exhaust manifold pressure signal;

[0032] S400. Confirm the fault diagnosis window and fault status.

[0033] Preferably, in S100, according to the scheduling period preset manually, the original AD signal value is continuously obtained by the exhaust manifold pressure sensor; and then the pressure signal is converted from the original AD signal value.

[0034] Preferably, the pulse frequency of the exhaust pulse period in S200 is expressed by the following formula:

[0035]

[0036] Where: f pulse is the exhaust pulse period; n is the engine speed; n cyl is the number of engine cylinders.

[0037] Preferably, in S200, a segment signal is generated in a scheduling task synchronized with the engine speed;

[0038] Each scheduling period generates a corresponding segment signal;

[0039] The segment signal is synchronized with the working cycle of each cylinder;

[0040] Continuous n cyl The segment signals correspond to one working cycle of the engine;

[0041] When the segment signal changes, the average value calculation flag is activated, and the pulse energy calculation flag is activated.

[0042] Preferably, in S300, the energy of the pulse signal within one pulse period is used as the characteristic value of the exhaust manifold pressure signal;

[0043] The energy of the pressure signal within a single pulse period is expressed by the following formula:

[0044]

[0045] Where: E is the pulse signal energy; T is the pulse period; p is the exhaust manifold pressure signal; p is the average value of the exhaust manifold pressure signal.

[0046] Preferably, in S300, the pressure signal collected in the current pulse period is also compared with the average value of the pressure signals collected in the previous pulse period; then, according to the comparison result, the following operations are performed:

[0047] If the difference between the pressure signal collected in the current pulse period and the average value of the pressure signals collected in the previous pulse period is greater than the manually preset difference threshold, the average value of the pressure signals collected in the previous pulse period is used to replace the pressure signal collected in the current pulse period;

[0048] If the difference between the pressure signal collected in the current pulse period and the average value of the pressure signals collected in the previous pulse period is not greater than the manually preset difference threshold, the pressure signal collected in the current pulse period is retained.

[0049] Preferably, S400 specifically includes the following steps:

[0050] S410. Determine whether the diagnostic window is open; then, according to the judgment result, the following operations are performed:

[0051] If the judgment result is that the diagnostic window is open, execute S420;

[0052] If the judgment result is that the diagnostic window is not open, end the process of the current icing blockage fault diagnosis method;

[0053] S420. Execute the icing blockage fault diagnosis process.

[0054] Preferably, determining whether the diagnostic window is open in S410 specifically includes the following steps:

[0055] S411. Obtain the ambient temperature of the vehicle;

[0056] S412. Compare the ambient temperature with the artificially preset ambient temperature threshold; then, based on the comparison result, perform the following operations:

[0057] If the ambient temperature is lower than the ambient temperature threshold, execute S413;

[0058] If the ambient temperature is not lower than the ambient temperature threshold, determine that the diagnostic window is not open; then end the process of determining whether the diagnostic window is open this time;

[0059] S413. Obtain the engine status information;

[0060] S414. Based on the engine status information, perform the following operations:

[0061] If the engine status information indicates that the current engine is in the running state, execute S415;

[0062] If the engine status information indicates that the current engine is not in the running state, determine that the diagnostic window is not open; then end the process of determining whether the diagnostic window is open this time;

[0063] S415. Obtain the electrical fault information;

[0064] S416. Based on the electrical fault information, perform the following operations:

[0065] If the electrical fault information indicates that no electrical fault is reported, execute S417;

[0066] If the electrical fault information indicates that an electrical fault is reported, determine that the diagnostic window is not open; then end the process of determining whether the diagnostic window is open this time;

[0067] S417. Obtain the rationality fault information;

[0068] S418. Based on the rationality fault information, perform the following operations:

[0069] If the rationality fault information indicates that no rationality fault is reported, determine that the diagnostic window is open; then end the process of determining whether the diagnostic window is open this time;

[0070] If the rationality fault information indicates that a rationality fault is reported, it is determined that the diagnostic window is not opened; then the process of determining whether the diagnostic window is opened this time ends.

[0071] Preferably, the icing blockage fault diagnosis process in S420 specifically includes the following steps:

[0072] S421. Obtain the pulse energy of the exhaust manifold pressure signal;

[0073] S422. Compare the pulse energy of the exhaust manifold pressure signal with the reasonable threshold of the pulse energy of the exhaust manifold pressure signal preset manually; then, according to the comparison result, perform the following operations:

[0074] If the pulse energy of the exhaust manifold pressure signal is less than the reasonable threshold of the pulse energy of the exhaust manifold pressure signal, execute S423;

[0075] If the pulse energy of the exhaust manifold pressure signal is not less than the reasonable threshold of the pulse energy of the exhaust manifold pressure signal, execute S424;

[0076] S423. Statistically calculate the duration during which the pulse energy of the exhaust manifold pressure signal is less than the reasonable threshold of the pulse energy of the exhaust manifold pressure signal; then, according to the statistical result, perform the following operations:

[0077] If the duration during which the pulse energy of the exhaust manifold pressure signal statistically obtained is less than the first duration threshold preset manually, execute S424;

[0078] If the duration during which the pulse energy of the exhaust manifold pressure signal statistically obtained is greater than the first duration threshold, it is determined that the icing blockage fault of the exhaust manifold pressure sensor is confirmed; then report the icing blockage fault of the exhaust manifold pressure sensor; then end the process of the icing blockage fault diagnosis method of the exhaust manifold pressure sensor this time;

[0079] S424. Determine that there is no confirmation of the icing blockage fault of the exhaust manifold pressure sensor; end the process of the icing blockage fault diagnosis method of the exhaust manifold pressure sensor this time; then return to and execute S422 again.

[0080] S425. Compare the amplitude of the exhaust manifold pressure with the reasonable threshold of the amplitude of the exhaust manifold pressure preset manually; then, according to the comparison result, perform the following operations:

[0081] If the exhaust manifold pressure amplitude is greater than or equal to the reasonable threshold value of the exhaust manifold pressure amplitude, it is determined that there is no confirmation of the icing and blockage fault of the exhaust manifold pressure sensor; then the process flow of the icing and blockage fault diagnosis method of the exhaust manifold pressure sensor in this time is ended;

[0082] If the exhaust manifold pressure amplitude is less than the reasonable threshold value of the exhaust manifold pressure amplitude, execute S426;

[0083] S426. Statistically calculate the duration during which the exhaust manifold pressure amplitude is less than the reasonable threshold value of the exhaust manifold pressure amplitude; then, according to the statistical result, perform the following operations:

[0084] If the duration during which the statistically obtained exhaust manifold pressure amplitude is less than the reasonable threshold value of the exhaust manifold pressure amplitude is less than the second duration threshold preset manually, it is determined that there is no confirmation of the icing and blockage fault of the exhaust manifold pressure sensor; then the process flow of the icing and blockage fault diagnosis method of the exhaust manifold pressure sensor in this time is ended;

[0085] If the duration during which the statistically obtained exhaust manifold pressure amplitude is less than the reasonable threshold value of the exhaust manifold pressure amplitude is less than the second duration threshold, return to and execute S421 again.

[0086] Preferably, the scheduling period is 1 ms; the engine is a four-stroke engine; the number of cylinders of the engine is 6.

[0087] Compared with the prior art, the present invention has the following advantages:

[0088] 1. The present invention meets the requirements of rapid warm-up for rapid identification, real-time monitoring, and accurate judgment of the icing and blockage fault of the exhaust pressure sensor;

[0089] 2. The present invention makes up for the defects that electrical diagnosis and rationality diagnosis cannot or cannot diagnose the icing fault of the P3 sensor in time;

[0090] 3. The present invention provides a diagnosis method for the icing fault of the exhaust manifold pressure sensor; the fault can be detected as soon as the engine starts, and the untrustworthy condition of the exhaust manifold sensor pressure signal caused by icing can be quickly eliminated. Description of the Drawings

[0091] Figure 1 It is a schematic flow chart of the P3 blockage fault diagnosis method for the specific embodiment of the present invention;

[0092] Figure 2 It is a schematic diagram of segment signal and calculation flag acquisition for the specific embodiment of the present invention;

[0093] Figure 3 It is a schematic diagram of P3 pressure average value calculation for the specific embodiment of the present invention;

[0094] Figure 4 Schematic diagram for calculating the P3 pressure pulse energy in a specific embodiment of the present invention. Specific embodiments

[0095] The following further clarifies the present invention in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. After reading the present invention, various equivalent modifications made by those skilled in the art fall within the scope defined by the appended claims of this application.

[0096] As Figure 1 shown, a method for diagnosing the fault of ice blockage of an exhaust manifold pressure sensor includes the following steps:

[0097] S100. Collect pressure signals.

[0098] In this specific embodiment, in S100, according to the manually preset scheduling period, the original AD signal value is continuously obtained by the exhaust manifold pressure sensor; and then the pressure signal is converted from the original AD signal value.

[0099] In this specific embodiment, the scheduling period is 1 ms.

[0100] In this specific embodiment, the engine is a four-stroke engine.

[0101] In this specific embodiment, the number of engine cylinders is 6.

[0102] S200. Calculate the exhaust pulse period.

[0103] In this specific embodiment, the pulse frequency of the exhaust pulse period in S200 is expressed by Equation (1):

[0104]

[0105] Where: f pulse is the exhaust pulse period; n is the engine speed; n cyl is the number of engine cylinders.

[0106] It should be noted that the principle of Equation (1) is that the fluctuation of the P3 pressure is caused by the pressure pulses generated by the sequential operation of each cylinder of the engine. For a four-stroke engine, the pulse frequency can be calculated according to Equation (1).

[0107] In this specific embodiment, in S200, a segment signal is generated in a scheduling task synchronized with the engine speed.

[0108] One corresponding segment signal is generated in each scheduling period.

[0109] The segment signal is synchronized with the working cycle of each cylinder.

[0110] Continuous n cyl segment signals correspond to one working cycle of the engine.

[0111] When the segment signal changes, the average value calculation flag is activated, and the pulse energy calculation flag is activated.

[0112] It should be noted that when n cyl = 6, that is, when the number of engine cylinders is 6, the engine is a six-cylinder engine; for a six-cylinder engine, the working cycle of each cylinder is 20 / n seconds, and this is also the time taken for the engine crankshaft to rotate 120°.

[0113] S300. Calculate the eigenvalue of the exhaust manifold pressure signal.

[0114] In this specific embodiment, in S300, the energy of the pulse signal within one pulse period is used as the eigenvalue of the exhaust manifold pressure signal.

[0115] The energy of the pressure signal within a single pulse period is expressed by Equation (2):

[0116]

[0117] Where: E is the pulse signal energy; T is the pulse period; p is the exhaust manifold pressure signal; is the average value of the exhaust manifold pressure signal.

[0118] It should be noted that the principle of S300 is as follows: when the intake pipe of the pressure sensor of the exhaust manifold is blocked, there is a significant difference in the energy of the pulse fluctuations of the original AD value signal collected by the sensor.

[0119] In this specific embodiment, in S300, the pressure signal collected in the current pulse period is also compared with the average value of the pressure signals collected in the previous pulse period; then, according to the comparison result, the following operations are performed:

[0120] If the difference between the pressure signal collected in the current pulse period and the average value of the pressure signals collected in the previous pulse period is greater than the manually preset difference threshold, the average value of the pressure signals collected in the previous pulse period is used to replace the pressure signal collected in the current pulse period.

[0121] If the difference between the pressure signal collected in the current pulse period and the average value of the pressure signals collected in the previous pulse period is not greater than the manually preset difference threshold, the pressure signal collected in the current pulse period is retained.

[0122] It should be noted that the principle of the above operation is as follows: The energy of the current cycle pulse signal is the integral of the square of the difference between the exhaust manifold pressure signal and the average exhaust manifold pressure within a pulse cycle. During the calculation of the P3 pressure pulse energy, the difference between the collected signal and the average value of the pressure signal in the previous cycle can be judged. When the difference is much larger than the average value, the average value of the previous cycle is used for substitution, so as to ensure the accuracy of the energy calculation.

[0123] S400. Confirm the fault diagnosis window and fault status.

[0124] In this specific embodiment, S400 specifically includes the following steps:

[0125] S410. Determine whether the diagnosis window is open; then, according to the judgment result, perform the following operations:

[0126] If the judgment result is that the diagnosis window is open, then execute S420.

[0127] If the judgment result is that the diagnosis window is not open, then end the process flow of this icing blockage fault diagnosis method.

[0128] In this specific embodiment, the determination of whether the diagnosis window is open in S410 specifically includes the following steps:

[0129] S411. Obtain the ambient temperature of the vehicle.

[0130] S412. Compare the ambient temperature with the artificially preset ambient temperature threshold; then, according to the comparison result, perform the following operations:

[0131] If the ambient temperature is lower than the ambient temperature threshold, then execute S413.

[0132] If the ambient temperature is not lower than the ambient temperature threshold, then determine that the diagnosis window is not open; then end the process flow of this determination of whether the diagnosis window is open.

[0133] S413. Obtain the engine status information.

[0134] S414. According to the engine status information, perform the following operations:

[0135] If the engine status information indicates that the current engine is in the running state, then execute S415.

[0136] If the engine status information indicates that the current engine is not in the running state, then determine that the diagnosis window is not open; then end the process flow of this determination of whether the diagnosis window is open.

[0137] S415. Obtain the electrical fault information.

[0138] S416. Based on the electrical fault information, perform the following operations:

[0139] If there is no electrical fault reported in the electrical fault information, execute S417.

[0140] If there is an electrical fault reported in the electrical fault information, determine that the diagnostic window is not opened; then end the process of determining whether the diagnostic window is opened this time.

[0141] S417. Obtain the reasonable fault information.

[0142] S418. Based on the reasonable fault information, perform the following operations:

[0143] If there is no reasonable fault reported in the reasonable fault information, determine that the diagnostic window is opened; then end the process of determining whether the diagnostic window is opened this time.

[0144] If there is a reasonable fault reported in the reasonable fault information, determine that the diagnostic window is not opened; then end the process of determining whether the diagnostic window is opened this time.

[0145] It should be noted that the principle of S410 is as follows: when the ambient temperature of the vehicle is lower than the threshold, the engine is in the running state, and there is no electrical and reasonable fault reported, the diagnostic window is opened for exhaust manifold icing fault diagnosis; when any condition is not met, the fault diagnostic window is closed, the fault is frozen, and no icing fault diagnosis is performed.

[0146] S420. Execute the icing blockage fault diagnosis process.

[0147] In this specific embodiment, the icing blockage fault diagnosis process in S420 specifically includes the following steps:

[0148] S421. Obtain the pulse energy of the exhaust manifold pressure signal.

[0149] S422. Compare the pulse energy of the exhaust manifold pressure signal with the reasonable threshold of the pulse energy of the exhaust manifold pressure signal preset manually; then based on the comparison result, perform the following operations:

[0150] If the pulse energy of the exhaust manifold pressure signal is less than the reasonable threshold of the pulse energy of the exhaust manifold pressure signal, execute S423.

[0151] If the pulse energy of the exhaust manifold pressure signal is not less than the reasonable threshold of the pulse energy of the exhaust manifold pressure signal, execute S424.

[0152] S423. Statistically calculate the duration during which the pulse energy of the exhaust manifold pressure signal is less than the reasonable threshold of the pulse energy of the exhaust manifold pressure signal; then based on the statistical result, perform the following operations:

[0153] If the duration during which the pulse energy of the exhaust manifold pressure signal obtained by statistics is less than the reasonable threshold of the pulse energy of the exhaust manifold pressure signal is less than the first duration threshold preset manually, then execute S424.

[0154] If the duration during which the pulse energy of the exhaust manifold pressure signal obtained by statistics is less than the reasonable threshold of the pulse energy of the exhaust manifold pressure signal is greater than the first duration threshold, then it is determined that the exhaust manifold pressure sensor is frozen and blocked; then report the exhaust manifold pressure sensor frozen and blocked fault; then end the process of the exhaust manifold pressure sensor frozen and blocked fault diagnosis method.

[0155] S424. Determine that there is no confirmation of the exhaust manifold pressure sensor frozen and blocked fault; end the process of the exhaust manifold pressure sensor frozen and blocked fault diagnosis method; then return to and execute S422 again.

[0156] S425. Compare the exhaust manifold pressure amplitude with the reasonable threshold of the exhaust manifold pressure amplitude preset manually; then according to the comparison result, perform the following operations:

[0157] If the exhaust manifold pressure amplitude is greater than or equal to the reasonable threshold of the exhaust manifold pressure amplitude, then determine that there is no confirmation of the exhaust manifold pressure sensor frozen and blocked fault; then end the process of the exhaust manifold pressure sensor frozen and blocked fault diagnosis method.

[0158] If the exhaust manifold pressure amplitude is less than the reasonable threshold of the exhaust manifold pressure amplitude, then execute S426.

[0159] S426. Statistically calculate the duration during which the exhaust manifold pressure amplitude is less than the reasonable threshold of the exhaust manifold pressure amplitude; then according to the statistical result, perform the following operations:

[0160] If the duration during which the exhaust manifold pressure amplitude obtained by statistics is less than the reasonable threshold of the exhaust manifold pressure amplitude is less than the second duration threshold preset manually, then determine that there is no confirmation of the exhaust manifold pressure sensor frozen and blocked fault; then end the process of the exhaust manifold pressure sensor frozen and blocked fault diagnosis method.

[0161] If the duration during which the exhaust manifold pressure amplitude obtained by statistics is less than the reasonable threshold of the exhaust manifold pressure amplitude is less than the second duration threshold, then return to and execute S421 again.

[0162] It should be noted that the principle of S420 is as follows: when the diagnostic window is opened and the pulse energy of the exhaust manifold pressure signal is less than the reasonable value for a certain period of time, the fault is confirmed, and the icing fault of the P3 pressure sensor is diagnosed; when the amplitude of the exhaust manifold pressure is greater than or equal to the reasonable value or the time when it is lower than the reasonable value does not reach a certain value, the icing fault of the P3 pressure sensor is not reported. The reasonable threshold of the pulse energy can be set and determined according to the engine working conditions, which is the theoretical pulse energy under different engine working conditions.

[0163] In order to further demonstrate the technical effects of the present invention, the applicant also conducted an actual machine test and placed the test process, test results, and process data in this specific embodiment; the specific test process, test results, and process data are as follows:

[0164] Taking the idle speed condition of 650 RPM as an example, for a six-cylinder engine, when all cylinders complete one working cycle, the crankshaft rotates 2 circles, that is, 720°. Therefore, the working cycle of each cylinder is the time used for the crankshaft to rotate (720° / 6) = 120°, that is, 20 / n seconds; where n is the engine speed.

[0165] As Figure 2 shown, the corresponding relationship between the pulsation period of the exhaust pressure sensor signal and the segment signal is related to the sensor position and the exhaust manifold layout. The P3 pressure signal is the data obtained by taking air from the single-side pressure sensor of the dual-channel exhaust manifold. The signal fluctuation obtained is caused by the operation of half of the cylinders of the engine. Each two segment signals correspond to the pulsation period of the signal obtained by one sensor. The segment signal is synchronized with the working cycle of each cylinder of the engine, and the calculation marks of the average value and the pulse energy are obtained by identifying the change of the segment signal.

[0166] As Figure 3 shown, when the calculation mark is recognized, the P3 pressure signal is accumulated, and the number of pressure signals is recorded. When the calculation mark is recognized again, the accumulated value of the pressure signal and the accumulated value of the number of pressure signals are saved, then reset, and the accumulation and counting are restarted. The average operation is performed on the pressure values recorded within one pulsation period of the P3 pressure signal to obtain the average value of the P3 pressure.

[0167] Compare the P3 pressure signal with the average value of the current cycle. When the difference is much larger than the average value, the average value is used for substitution. As Figure 4 shown, when the pulse energy calculation mark is activated, the square of the difference between the current P3 pressure and its average value is accumulated to obtain the pulse energy of the current interval. When the calculation mark is activated again, the accumulated value is saved, and the accumulation is restarted after reset. The sum of the pulse energies in the two previous and subsequent calculation intervals is the pulse energy of the current pulsation period of the P3 pressure signal.

[0168] When the ambient temperature is lower than the threshold value, the engine is in an operating state, and there are no electrical or rationality faults reported, the fault diagnosis window is opened. When the single-cycle pulse energy of the calculated P3 pressure signal is lower than the reasonable value for a certain period of time, the exhaust manifold pressure sensor icing fault is reported.

[0169] In the above detailed description, various features are combined in a single embodiment to simplify the present disclosure. This method of disclosure should not be construed as reflecting an intention that the embodiments of the claimed subject matter require more features than are clearly recited in each claim. On the contrary, as reflected in the appended claims, the present invention lies in a state with fewer features than all the features of the disclosed single embodiment. Therefore, the appended claims are hereby expressly incorporated into the detailed description, where each claim stands alone as a separate preferred embodiment of the present invention.

[0170] In order to enable any person skilled in the art to implement or use the present invention, the above-described disclosed embodiments are described. For those skilled in the art; various modification methods of these embodiments are obvious, and the general principles defined herein can also be applied to other embodiments without departing from the spirit and protection scope of the present disclosure. Therefore, the present disclosure is not limited to the embodiments given herein, but is consistent with the broadest scope of the principles and novel features disclosed in this application.

[0171] The above description includes examples of one or more embodiments. Of course, it is impossible to describe all possible combinations of components or methods for describing the above embodiments, but those of ordinary skill in the art should recognize that each embodiment can be further combined and arranged. Therefore, the embodiments described herein are intended to cover all such changes, modifications, and variations that fall within the protection scope of the appended claims. In addition, with respect to the term "comprising" used in the specification or claims, the way this term is covered is similar to the term "including", as explained when "including," is used as a transitional word in the claims. In addition, any term "or" used in the claims or the specification is intended to mean "non-exclusive or".

[0172] The specific embodiments described above further elaborate on the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above description is only the specific embodiments of the present invention and is not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for diagnosing the icing and blockage fault of an exhaust manifold pressure sensor, characterized in that: It includes the following steps: S100. Collect pressure signals; S200. Calculate the exhaust pulse period; S300. Calculate the eigenvalue of the exhaust manifold pressure signal; S400. Confirm the fault diagnosis window and fault status; In S100, according to the artificially preset scheduling period, the original AD signal value is continuously obtained by the exhaust manifold pressure sensor; and then the original AD signal value is converted into a pressure signal; In S200, the pulse frequency of the exhaust pulse period is expressed by the following formula: Where: fpulse is the exhaust pulse frequency; n is the engine speed; ncyl is the number of engine cylinders; In S300, the pulse signal energy within one pulse period is used as the eigenvalue of the exhaust manifold pressure signal; The energy of the pressure signal within a single pulse period is expressed by the following formula: Where: E is the energy of the pulse signal; T is the pulse period, and the pulse period T and the fpulse exhaust pulse frequency are reciprocal to each other; p is the exhaust manifold pressure signal; is the average value of the exhaust manifold pressure signal; S400 includes: S410. Determine whether the diagnosis window is open; and then according to the judgment result, perform the following operations: If the judgment result is that the diagnosis window is open, then execute S420; If the judgment result is that the diagnosis window is not open, then end the process of this icing blockage fault diagnosis method; S420. Execute the icing blockage fault diagnosis process; S420 includes: S421. Obtain the pulse energy of the exhaust manifold pressure signal; S422. Compare the pulse energy of the exhaust manifold pressure signal with the reasonable threshold of the pulse energy of the exhaust manifold pressure signal preset manually; and then according to the comparison result, perform the following operations: If the pulse energy of the exhaust manifold pressure signal is less than the reasonable threshold of the pulse energy of the exhaust manifold pressure signal, then execute S423; If the pulse energy of the exhaust manifold pressure signal is not less than the reasonable threshold of the pulse energy of the exhaust manifold pressure signal, then execute S424; S423. Statistically calculate the duration during which the pulse energy of the exhaust manifold pressure signal is less than the reasonable threshold of the pulse energy of the exhaust manifold pressure signal; and then according to the statistical result, perform the following operations: If the statistically calculated duration during which the pulse energy of the exhaust manifold pressure signal is less than the reasonable threshold of the pulse energy of the exhaust manifold pressure signal is less than the first duration threshold preset manually, then execute S424; If the statistically calculated duration during which the pulse energy of the exhaust manifold pressure signal is less than the reasonable threshold of the pulse energy of the exhaust manifold pressure signal is greater than the first duration threshold, then confirm the icing blockage fault of the exhaust manifold pressure sensor; then report the icing blockage fault of the exhaust manifold pressure sensor; and then end the process of this icing blockage fault diagnosis method of the exhaust manifold pressure sensor; S424. Determine that there is no confirmation of the icing blockage fault of the exhaust manifold pressure sensor; end the process of this icing blockage fault diagnosis method of the exhaust manifold pressure sensor; and then return to and execute S422 again; The scheduling period is 1 ms; the engine is a four-stroke engine; the number of engine cylinders is 6.

2. The exhaust manifold pressure sensor icing and clogging fault diagnosis method according to claim 1, characterized in that: In S200, a segment signal is generated in a scheduling task synchronized with the engine speed; One corresponding segment signal is generated in each of the scheduling periods; The segment signal is synchronized with the working cycle of each cylinder; Continuous ncyl segment signals correspond to one working cycle of the engine; When the segment signal changes, the average value calculation identifier is activated, and the pulse energy calculation flag is activated.

3. The method for diagnosing the icing and blockage fault of the exhaust manifold pressure sensor according to claim 2, wherein: In S300, the pressure signal collected in the current pulse period is also compared with the average value of the pressure signals collected in the previous pulse period; then, based on the comparison result, the following operations are performed: If the difference between the pressure signal collected in the current pulse period and the average value of the pressure signals collected in the previous pulse period is greater than the manually preset difference threshold, the average value of the pressure signals collected in the previous pulse period is used to replace the pressure signal collected in the current pulse period; If the difference between the pressure signal collected in the current pulse period and the average value of the pressure signals collected in the previous pulse period is not greater than the manually preset difference threshold, the pressure signal collected in the current pulse period is retained.

4. The exhaust manifold pressure sensor icing and blockage fault diagnosis method according to claim 3, characterized in that: In S410, it is determined whether the diagnostic window is open, which specifically includes the following steps: S411. Obtain the ambient temperature of the vehicle; S412. Compare the ambient temperature with the manually preset ambient temperature threshold; then, based on the comparison result, the following operations are performed: If the ambient temperature is lower than the ambient temperature threshold, execute S413; If the ambient temperature is not lower than the ambient temperature threshold, it is determined that the diagnostic window is not open; then, end the process of determining whether the diagnostic window is open this time; S413. Obtain the engine status information; S414. Based on the engine status information, the following operations are performed: If the engine status information indicates that the current engine is in the running state, execute S415; If the engine status information indicates that the current engine is not in the running state, it is determined that the diagnostic window is not open; then, end the process of determining whether the diagnostic window is open this time; S415. Obtain the electrical fault information; S416. Based on the electrical fault information, the following operations are performed: If the electrical fault information indicates that no electrical fault is reported, execute S417; If the electrical fault information indicates that an electrical fault is reported, it is determined that the diagnostic window is not open; then, end the process of determining whether the diagnostic window is open this time; S417. Obtain the rationality fault information; S418. Based on the rationality fault information, the following operations are performed: If the rationality fault information indicates that no rationality fault is reported, it is determined that the diagnostic window is open; then, end the process of determining whether the diagnostic window is open this time; If the rationality fault information indicates that a rationality fault is reported, it is determined that the diagnostic window is not open; then, end the process of determining whether the diagnostic window is open this time.

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