A hybrid vehicle fault diagnosis method, diagnosis device, storage medium and controller

Abstract

The present application belongs to the technical field of vehicle engineering, and particularly relates to a hybrid vehicle fault diagnosis method, a diagnosis device, a storage medium and a controller; by introducing a discriminant condition coexisting with a potential fault with a high probability and performing logical synthesis, an effective discrimination method and product for engine flameout fault of a hybrid vehicle are given; specifically, the discrimination is based on detection of motor torque, air-fuel ratio and supercharging pressure; according to different engine structures, the supercharging pressure processing is optional; the above scheme can increase the engine flameout fault diagnosis capability of the hybrid vehicle without changing the hardware of the hybrid vehicle, by using software upgrading of an engine management system (EMS) and / or a vehicle control unit (VCU), so that efficient functional upgrading is realized with better technical and economic indicators, the operation efficiency of the hybrid vehicle is improved, and frequent working condition switching is avoided; meanwhile, the hybrid vehicle exhaust purification unit is prevented from entering a dangerous working condition, and secondary hazards are effectively avoided.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of vehicle engineering, and particularly relates to a hybrid vehicle fault diagnosis method, a diagnosis device, a storage medium and a controller. BACKGROUND

[0002] When a conventional fuel system engine is normally running, an engine management system (EMS) calculates the required amount of fuel according to the intake amount of the engine, and then performs fuel injection and ignition at the correct injection phase and ignition time, so that the engine maintains normal operation. If the engine is caused to misfire due to some accidental reasons, the engine speed will be sharply reduced below the minimum speed threshold in a very short time, and the EMS will stop fuel injection and ignition, so that a large amount of unburned fuel is not injected into the cylinder.

[0003] However, for a hybrid vehicle, if the engine is caused to misfire due to accidental reasons (such as a spark plug that cannot ignite) in the working condition of engine operation (power generation or power output), the engine speed will still be maintained at a high speed due to the compensation of the motor for the torque of the engine. The EMS system fails to identify that the engine has failed to normally ignite at this time, and will continue to issue fuel injection and ignition instructions, thereby causing a large amount of unburned fuel to be injected into the cylinder and discharged into the catalyst with the airflow. Since the catalyst is in a high-temperature state, the fuel may be ignited again at this time, resulting in “afterburning”, which causes the catalyst to be ablated and even the catalyst to burst.

[0004] Since there are many abnormal misfire faults, even if the EMS can diagnose some component faults, there are still many faults that cannot be diagnosed in time, such as the abnormal water temperature causing the mixture to be too rich, the EGR condensate water entering the engine, or the spark plug ignition energy being insufficient due to the aging of the ignition coil, etc. All of these can cause the engine to fail to normally ignite, and the engine fails to stop fuel injection, which can all cause the above-mentioned “afterburning” phenomenon.

[0005] Although the EMS can diagnose some component faults, such as the driving stage fault of the ignition coil, and stop fuel injection, there are still many faults that the EMS cannot diagnose in time and accurately, such as the case where water enters the combustion chamber, which can cause a large amount of fuel to be discharged into the catalyst for “afterburning”.

[0006] Therefore, it is necessary to use a separate method to diagnose that the engine is in a misfire state in time, stop fuel injection, and give a fault signal to the vehicle control unit (VCU) or related components when the engine of a hybrid vehicle is in an abnormal misfire state, so as to switch the vehicle to a pure electric mode and prompt the driver that the engine has a fault and needs to be repaired. SUMMARY

[0007] The embodiment of the present application discloses a hybrid vehicle fault diagnosis method, comprising a first torque difference discrimination step, a second air-fuel ratio discrimination step; the first torque difference discrimination step obtains the current torque of the motor of the hybrid vehicle, if the difference between the current torque and the target torque is greater than the preset torque difference threshold, the first abnormal flag is set; the second air-fuel ratio discrimination step obtains the air-fuel ratio signal, if the difference between the air-fuel ratio signal and the target air-fuel ratio is greater than the preset air-fuel ratio difference threshold, the second abnormal flag is set; if the first abnormal flag setting and the second abnormal flag setting are established at the same time, it is judged that the engine of the hybrid vehicle is in the off state.

[0008] Among them, the air-fuel ratio signal can be detected by the oxygen sensor.

[0009] Considering that the engine management system EMS itself has fuel correction, the actual air-fuel ratio signal (usually represented by the symbol λ) obtained by the oxygen sensor cannot directly represent whether the system fuel mixture is lean; At the same time, the target air-fuel ratio is not equal to 1 in special working conditions (such as part enrichment protection working condition and the like); At this time, the actual air-fuel ratio λ needs to be processed to determine whether the mixture is in a lean state.

[0010] Among them, the air-fuel ratio signal Lambda can be defined as:

[0011] Lambda=λ+fuel correction compensation-target air-fuel ratio, and the air-fuel ratio signal Lambda is filtered to obtain the actual air-fuel ratio parameter Lambdafil used for discrimination.

[0012] At this time, the air-fuel ratio signal (which can use the air-fuel ratio parameter Lambdafil) has also undergone fuel correction compensation and / or air-fuel ratio filtering; Among them, the fuel correction compensation can be used for part enrichment protection working condition.

[0013] Further, the hybrid vehicle fault diagnosis method can further set a third supercharging difference discrimination step; The third supercharging difference discrimination step is used to confirm that the engine is in a supercharged state; If the engine is not in a supercharged state, the fault diagnosis process is ended, if the engine is in a supercharged state, the fourth pressure difference discrimination step is executed to discriminate the working condition of the engine with supercharging function.

[0014] Specifically, the fourth pressure difference discrimination step obtains the current supercharging pressure of the engine, if the difference between the target supercharging pressure of the engine and the current supercharging pressure is greater than the preset supercharging difference threshold, the third abnormal flag is set; If the first abnormal flag setting, the second abnormal flag setting and the third abnormal flag setting are established at the same time, it is judged that the engine of the hybrid vehicle is in the off state; Otherwise, the engine does not have the off fault.

[0015] To ensure the safety of the vehicle, further detection of the exhaust gas temperature can also be performed; wherein if the engine exhaust gas catalyst temperature is greater than a preset first temperature threshold of safety risk and / or the exhaust gas catalyst temperature is greater than a preset second temperature threshold and lasts for more than a second temperature duration, it is determined that the engine of the hybrid vehicle is in an off state.

[0016] In addition, in an actual system, the above-mentioned current torque, air-fuel ratio signal and / or current boost pressure can be provided by an engine management system EMS; the above-mentioned first abnormal flag, second abnormal flag and / or third abnormal flag can also be transmitted to a vehicle control unit VCU or a related processing unit for decision-making.

[0017] Correspondingly, the embodiment of the application also discloses a hybrid vehicle fault diagnosis device, comprising a first torque difference discrimination unit and a second air-fuel ratio discrimination unit; the first torque difference discrimination unit obtains the current torque of the motor of the hybrid vehicle, and if the difference between the current torque and the target torque is greater than a preset torque difference threshold, the first abnormal flag is set; the second air-fuel ratio discrimination unit obtains the air-fuel ratio signal, and if the difference between the air-fuel ratio signal and the target air-fuel ratio is greater than a preset air-fuel ratio difference threshold, the second abnormal flag is set; if the first abnormal flag is set and the second abnormal flag is set at the same time, it is determined that the engine of the hybrid vehicle is in an off state; if necessary, fault information or related prompt / warning data can be provided to the corresponding control unit.

[0018] The air-fuel ratio signal can generally be detected by an oxygen sensor.

[0019] However, considering that the engine management system EMS itself has fuel correction, the actual air-fuel ratio signal (usually represented by the symbol λ) obtained by the oxygen sensor cannot directly represent whether the system fuel mixture is lean; at the same time, the special working condition that the target air-fuel ratio is not equal to 1 (for example, the part enrichment protection working condition and the like) must also be considered; at this time, the actual air-fuel ratio λ needs to be processed, so that it can be judged whether the mixture is in a lean state.

[0020] The air-fuel ratio signal Lambda can be defined as:

[0021] Lambda = λ + fuel correction compensation - target air-fuel ratio, and the air-fuel ratio signal Lambda is filtered to obtain the actual air-fuel ratio parameter Lambdafil used for discrimination.

[0022] At this time, the air-fuel ratio signal (which can use the air-fuel ratio parameter Lambdafil) has also undergone fuel correction compensation and / or air-fuel ratio filtering; wherein the fuel correction compensation can be used for the part enrichment protection working condition.

[0023] In actual system, the air-fuel ratio signal can be a signal compensated by fuel correction and / or filtered by air-fuel ratio; the fuel correction can refer to data for part enrichment protection condition.

[0024] Further, for the engine with supercharging device, the hybrid vehicle fault diagnosis device can further improve the detection capability by setting a third supercharging difference discrimination unit.

[0025] Specifically, the third supercharging difference discrimination unit is used to confirm whether the engine is in supercharging condition; if the engine is not in supercharging condition, the fault diagnosis process is ended; if the engine is in supercharging condition, the fourth pressure difference discrimination unit is started or opened to detect the fault of the engine.

[0026] The fourth pressure difference discrimination unit can discriminate by acquiring the current supercharging pressure of the engine; if the difference between the target supercharging pressure and the current supercharging pressure of the engine is greater than a preset supercharging difference threshold, the third abnormal flag is set; at this time, if the first abnormal flag, the second abnormal flag and the third abnormal flag are all set, it is determined that the engine of the hybrid vehicle is in the off state; otherwise, it is considered that the engine does not have the off fault.

[0027] Further, in order to ensure the safety of the engine, the hybrid vehicle fault diagnosis device can further add a temperature detection unit or use the existing temperature detection unit; specifically, if the engine exhaust catalyst temperature is greater than a preset first safety risk temperature threshold and / or the exhaust catalyst temperature is greater than a preset second temperature threshold and lasts for more than a second temperature duration, it is determined that the engine of the hybrid vehicle is in the off state.

[0028] Further, in order to improve the universality of the hybrid vehicle fault diagnosis device and serve the vehicle fault diagnosis, the signal acquisition can use the output of the existing detection unit of the vehicle, and the intermediate data can be used for the decision of other units of the vehicle.

[0029] Specifically, the current torque, air-fuel ratio signal and / or current supercharging pressure can be provided by the engine management system EMS; the first abnormal flag, the second abnormal flag and / or the third abnormal flag can be transmitted to the vehicle control unit VCU or the related unit for decision.

[0030] Correspondingly, the embodiment of the present application also discloses a computer storage medium and a controller, which can be used to realize the above-mentioned diagnosis process or product in a hybrid vehicle or other vehicle; the computer storage medium comprises a storage medium body for storing a computer program; the computer program can realize any one of the hybrid vehicle fault diagnosis methods when executed by a microprocessor; similarly, the controller comprises any one of the hybrid vehicle fault diagnosis devices and / or any one of the computer storage media, and can also be used to realize the same inventive concept, and the realization process will not be repeated.

[0031] In summary, the present application gives an effective discrimination method and product for the engine stall fault of a hybrid vehicle by introducing a discrimination condition coexisting with a potential fault with a high probability and performing logical synthesis.

[0032] Specifically, the discrimination is based on the detection of the motor torque, the air-fuel ratio and the supercharging pressure; according to the difference in the engine structure, the processing of the supercharging pressure is optional; the above scheme can increase the engine stall fault diagnosis capability of the hybrid vehicle by using the software upgrade of the engine management system (EMS) and / or the vehicle control unit (VCU) without changing the hardware of the hybrid vehicle.

[0033] The product realizes efficient function upgrade with better technical and economic indicators, improves the operation efficiency of the hybrid vehicle and can avoid frequent working condition switching; at the same time, the product can avoid the exhaust purification unit of the hybrid vehicle entering a dangerous working condition and can effectively avoid secondary hazards.

[0034] It should be noted that the terms such as "first", "second" and the like used in this paper are only used to describe the elements in the technical solutions and do not constitute a limitation on the technical solutions, nor can they be understood as an indication or suggestion of the importance of the corresponding elements; the elements with "first", "second" and the like indicate that at least one element is included in the corresponding technical solution. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the present application, and to facilitate further understanding of the technical effects, technical features and purposes of the present application, the present application will be described in detail below with reference to the drawings, which constitute an essential part of the specification and are used to illustrate the technical solutions of the present application together with the embodiments of the present application, but do not constitute a limitation on the present application.

[0036] The same reference numerals in the drawings represent the same components, specifically:

[0037] Figure 1 The air-fuel ratio change curve for the embodiment of the present application.

[0038] Figure 2 The pressure change curve of the embodiment of the present application.

[0039] Figure 3 The fault diagnosis flowchart of the embodiment of the present application Figure 1 .

[0040] Figure 4 The flowchart of the method embodiment of the present application Figure 2 .

[0041] Figure 5 The structural schematic diagram of the device embodiment of the present application.

[0042] Figure 6 The product layout structure schematic of the present application Figure 1 .

[0043] Figure 7 The product layout structure schematic of the present application Figure 2 .

[0044] Figure 8 The product layout structure schematic of the present application Figure 3 .

[0045] Wherein:

[0046] 001 - normal engine operating state;

[0047] 010 - fault response step;

[0048] 100 - first torque difference discrimination step;

[0049] 200 - second air-fuel ratio discrimination step;

[0050] 300 - third supercharging difference discrimination step;

[0051] 400 - fourth pressure difference discrimination step;

[0052] 600 - electric motor;

[0053] 700 - hybrid vehicle fault diagnosis device;

[0054] 900 - hybrid vehicle;

[0055] 901 - controller;

[0056] 903 - computer storage medium;

[0057] 909 - engine. Embodiment

[0058] The application will be described in further detail below with reference to the drawings and embodiments. Of course, the specific embodiments described below are only to explain the technical solutions of the application, and are not a limitation on the application. In addition, the parts described in the embodiments or the drawings are only illustrative of the relevant parts of the application, and are not the whole of the application.

[0059] As shown in Figure 3 、 Figure 4 , a flowchart of a hybrid vehicle fault diagnosis method is given, and the core process includes a first torque difference discrimination step 100 and a second air-fuel ratio discrimination step 200.

[0060] The first torque difference discrimination step 100 obtains the current torque of the motor 600 of the hybrid vehicle 900 as shown in Figure 6 、 7 8, and if the difference between the current torque and the target torque is greater than a preset torque difference threshold, the first abnormal flag is set.

[0061] At the same time, the second air-fuel ratio discrimination step 200 obtains an air-fuel ratio signal, and if the difference between the air-fuel ratio signal and the target air-fuel ratio is greater than a preset air-fuel ratio difference threshold, the second abnormal flag is set.

[0062] Further, if the first abnormal flag setting and the second abnormal flag setting are both true at the same time, it can be determined that the engine 909 of the hybrid vehicle 900 is in an off state.

[0063] In practical applications, the air-fuel ratio signal is detected by an oxygen sensor.

[0064] However, considering that the engine management system EMS itself has fuel correction, the actual air-fuel ratio signal (usually represented by the symbol λ) obtained by the oxygen sensor cannot directly represent whether the system fuel mixture is lean; at the same time, the target air-fuel ratio is not equal to 1 in special working conditions (such as part enrichment protection working conditions and the like); at this time, the actual air-fuel ratio λ needs to be processed to determine whether the mixture is in a lean state.

[0065] Wherein, the air-fuel ratio signal Lambda can be defined as:

[0066] Lambda = λ + fuel correction compensation - target air-fuel ratio, and the air-fuel ratio signal Lambda is filtered to obtain the actual air-fuel ratio parameter Lambdafil used for discrimination.

[0067] At this time, the air-fuel ratio signal (which can use the air-fuel ratio parameter Lambdafil) has also undergone fuel correction compensation and / or air-fuel ratio filtering; wherein the fuel correction compensation can be used for part enrichment protection working conditions.

[0068] Specifically, the air-fuel ratio signal can also be compensated by fuel correction and / or air-fuel ratio filtering; wherein the fuel correction can adopt parameters of a part-rich protection working condition.

[0069] Further, the hybrid vehicle fault diagnosis method also includes a third boost pressure difference discrimination step 300 as shown in Figure 3 、 4 illustrated in the figure; the third boost pressure difference discrimination step 300 is used to confirm that the engine 909 is in a boost working condition as shown in Figure 6 、 7 8.

[0070] Specifically, if the engine 909 is not in the boost working condition, the fault diagnosis process can be ended early; if the engine 909 is in the boost working condition, the fourth pressure difference discrimination step 400 as shown in Figure 3 、 4 can be continued to be executed.

[0071] Wherein, the fourth pressure difference discrimination step 400 acquires the current boost pressure of the engine 909, and if the difference between the target boost pressure and the current boost pressure of the engine 909 is greater than a preset boost pressure difference threshold, the third abnormal flag is set.

[0072] Specifically, if the first abnormal flag is set, the second abnormal flag is set, and the third abnormal flag is set at the same time, it is determined that the engine 909 of the hybrid vehicle 900 is in an off state; otherwise, it is determined that the engine 909 does not have an off fault.

[0073] As described above, in order to ensure the safety of the engine, the hybrid vehicle fault diagnosis device can also be provided with a temperature detection unit or use the existing temperature detection unit to detect the exhaust gas temperature.

[0074] Specifically, if the exhaust gas catalyst temperature of the engine 909 is greater than a preset safety risk first temperature threshold and / or the exhaust gas catalyst temperature is greater than a preset second temperature threshold and lasts for more than a second temperature duration, it is determined that the engine 909 of the hybrid vehicle 900 is in an off state.

[0075] Similarly, in order to improve the universality of the hybrid vehicle fault diagnosis device and serve the vehicle fault diagnosis, the signal acquisition also uses the output of the detection unit of the vehicle engine EMS; the intermediate data can also be used for the decision of the vehicle VCU controller or other units.

[0076] Wherein, the current torque, the air-fuel ratio signal, and / or the current boost pressure are provided by the engine management system EMS; the first abnormal flag, the second abnormal flag, and / or the third abnormal flag can be transmitted to the vehicle control unit VCU or the related measurement and control unit for decision.

[0077] Correspondingly, if Figure 5Also disclosed is a hybrid vehicle fault diagnosis device 700, comprising a first torque difference discrimination unit 710 and a second air-fuel ratio discrimination unit 720.

[0078] The first torque difference discrimination unit 710 discriminates the torque change by obtaining the current torque of the motor 600 of the hybrid vehicle 900: if the difference between the current torque and the target torque is greater than the preset torque difference threshold, the first abnormality flag is set.

[0079] On the other hand, the second air-fuel ratio discrimination unit 720 obtains the air-fuel ratio signal, and if the difference between the air-fuel ratio signal and the target air-fuel ratio is greater than the preset air-fuel ratio difference threshold, the second abnormality flag is set.

[0080] At this time, if the first abnormality flag is set and the second abnormality flag is set at the same time, it can be determined that the engine 909 of the hybrid vehicle 900 is in the off state.

[0081] Generally, the air-fuel ratio signal of the hybrid vehicle fault diagnosis device 700 can be obtained by the oxygen sensor.

[0082] However, considering that the engine management system EMS itself has fuel correction, the actual air-fuel ratio signal (usually represented by the symbol λ) obtained by the oxygen sensor cannot directly represent whether the system fuel mixture is lean; At the same time, it is also necessary to consider the special working condition that the target air-fuel ratio is not equal to 1 (for example, the part enrichment protection working condition and the like); At this time, it is necessary to process the actual air-fuel ratio λ to determine whether the mixture is in a lean state.

[0083] The air-fuel ratio signal Lambda can be defined as:

[0084] Lambda = λ + fuel correction compensation - target air-fuel ratio, and the air-fuel ratio signal Lambda is filtered to obtain the actual air-fuel ratio parameter Lambdafil used for discrimination.

[0085] At this time, the air-fuel ratio signal (which can use the air-fuel ratio parameter Lambdafil) has also undergone fuel correction compensation and / or air-fuel ratio filtering; wherein the fuel correction compensation can be used for part enrichment protection working condition.

[0086] Specifically, the air-fuel ratio signal can also undergo fuel correction compensation and / or air-fuel ratio filtering; wherein the fuel correction compensation can use the parameters of the part enrichment protection working condition.

[0087] The air-fuel ratio signal has undergone fuel correction compensation and / or air-fuel ratio filtering; the fuel correction compensation is used for part enrichment protection working condition.

[0088] Further, the hybrid vehicle fault diagnosis apparatus 700 is also provided with a third supercharging difference discrimination unit 730 and a fourth pressure difference discrimination unit 740.

[0089] Specifically, the third supercharging difference discrimination unit 730 is configured to confirm whether the engine 909 is in a supercharging working condition; if the engine 909 is not in the supercharging working condition, the fault diagnosis process can be ended early to save the processor cost; if the engine 909 is in the supercharging working condition, the fourth pressure difference discrimination unit 740 can be started or enabled.

[0090] Specifically, the third supercharging difference discrimination unit 730 is configured to confirm whether the engine 909 is in a supercharging working condition; if the engine 909 is not in the supercharging working condition, the fault diagnosis process can be ended early to save the processor cost; if the engine 909 is in the supercharging working condition, the fourth pressure difference discrimination unit 740 can be started or enabled.

[0091] Specifically, if the first abnormal flag, the second abnormal flag and the third abnormal flag are all set, it is determined that the engine 909 of the hybrid vehicle 900 is in an engine-out condition; otherwise, it is determined that the engine 909 does not have an engine-out fault.

[0092] As described above, in order to ensure the safety of the engine, the hybrid vehicle fault diagnosis apparatus can also be provided with a temperature detection unit or use the existing temperature detection unit to detect the exhaust gas temperature.

[0093] Specifically, if the exhaust gas catalytic converter temperature of the engine 909 is greater than a preset safety risk first temperature threshold and / or the exhaust gas catalytic converter temperature is greater than a preset second temperature threshold and lasts for more than a second temperature duration, it is determined that the engine 909 of the hybrid vehicle 900 is in an engine-out condition.

[0094] Similarly, in order to improve the versatility of the hybrid vehicle fault diagnosis apparatus and serve the vehicle fault diagnosis, the signal collection also uses the output of the detection unit of the vehicle engine EMS, and the intermediate data can also be used for the decision of the vehicle VCU controller or other units.

[0095] Specifically, the current torque, air-fuel ratio signal and / or current supercharging pressure are provided by the engine management system EMS; and the first abnormal flag, the second abnormal flag and / or the third abnormal flag can also be transmitted to the vehicle control unit VCU for auxiliary decision.

[0096] In practical applications, some signals of the existing EMS system can be used to upgrade the function of the EMS to diagnose whether the engine is in an engine-out condition.

[0097] Specifically, the following three conditions can be focused on; and the engine-out condition can be determined through the confirmed process.

[0098] As mentioned above, the three conditions include: first, the motor torque rises sharply; second, the engine air-fuel ratio is greatly lean; third, the supercharging pressure drops sharply.

[0099] First, the motor torque condition: when the engine 909 is off, the hybrid vehicle 900 will automatically compensate for the torque lost by the engine 909 to ensure smooth rotation; therefore, the torque of the motor will increase sharply when the engine 909 is off.

[0100] Specifically, if the motor torque-target torque> torque difference threshold value, the motor torque condition is met.

[0101] Wherein, the torque difference threshold value can be designed as a torque map MAP with speed / load as coordinates; its value should refer to the torque of the engine 909 under normal operation in this working condition.

[0102] Specifically, the torque difference threshold value can be calibrated as 70% of the torque that the engine 909 should output under this working condition; at this time, it is considered that the engine has lost 70% of the torque, and the system can preliminarily determine that the engine 909 may have been off.

[0103] Second, the air-fuel ratio condition: since the air-fuel ratio is greatly lean is one of the characteristics when off; therefore, the air-fuel ratio signal is used as one of the conditions.

[0104] As shown in Figure 1 , about 1.3 seconds after the engine is off, the air-fuel ratio signal is already lean to 1.2; at this time, the catalyst temperature just starts to rise, only to 640℃, with sufficient distinction and diagnosis time; at this time, if the contingency plan or fault response step 010 is taken, the engine and exhaust system can also be ensured to operate safely.

[0105] Wherein, considering that the EMS system itself has fuel correction; therefore, the actual air-fuel ratio signal λ obtained through the oxygen sensor cannot directly represent whether the system is lean; at the same time, the target air-fuel ratio is not equal to 1 in special working conditions (such as part enrichment protection working condition, etc.); therefore, λ needs to be processed before it can be used to judge whether it is lean. Specifically, the air-fuel ratio signal Lambda can be defined as:

[0106] Lambda=λ+fuel correction compensation-target air-fuel ratio;

[0107] The air-fuel ratio signal Lambda can also be filtered to obtain the Lambdafil signal.

[0108] At this time, if Lambdafil> air-fuel ratio difference threshold value, it is considered that the air-fuel ratio condition is met.

[0109] Thirdly, the supercharging pressure condition: when the engine is off, the exhaust back pressure decreases, the speed of the supercharger decreases significantly, and thus the supercharging pressure decreases significantly.

[0110] Specifically, as shown in FIG. 9, when the engine 909 is off, the supercharging pressure of the engine 909 decreases significantly; at about 2.3 seconds, the difference between the target supercharging pressure and the actual supercharging pressure reaches about 370 hpa, and the catalyst temperature of the engine 909 only increases to about 760℃, which provides sufficient discrimination and diagnosis time for the discrimination process. Figure 2

[0111] If the target supercharging pressure-actual supercharging pressure> supercharging difference threshold, it is considered that the supercharging pressure condition is met.

[0112] In addition, if the engine 909 operates in a non-supercharged working condition, this condition can be ignored.

[0113] The engine abnormal off diagnosis of the embodiment can be performed by using the existing oxygen sensor signal, the supercharging pressure signal, and the motor torque signal of the hybrid vehicle 900 system, and the "afterburning" is prevented.

[0114] Specifically, the technical effect is to provide higher system integration and upgrading efficiency, and the engine off state can be quickly implemented by upgrading the control software without adding new hardware.

[0115] At the same time, the frequent switching between the working modes of the hybrid vehicle 900 can be reduced, and the vehicle operating efficiency is ensured.

[0116] In addition, the above process can be completed in real time by using the existing system, and the decision process can be quickly completed in the off instant (usually within 2-3 seconds); thus, the EMS can cut off the engine off state before the catalyst is damaged, and the fault is prevented from spreading.

[0117] Correspondingly, as shown in FIGS. 9, 10, and 8, the embodiment of the present application also discloses a computer storage medium 903 and a controller 901, which can be used to implement the above diagnosis process or product in the hybrid vehicle 900 or other vehicles. Figure 6 7 The computer storage medium 903 includes a storage medium body for storing a computer program; the computer program can implement any one of the above hybrid vehicle fault diagnosis methods when executed by a microprocessor.

[0118] Similarly, the controller 901 includes any one of the hybrid vehicle fault diagnosis apparatus 700 and / or any one of the computer storage medium 903, which can also be used to implement the same inventive concept.

[0119] Similarly, the controller 901 includes any one of the hybrid vehicle fault diagnosis apparatus 700 and / or any one of the computer storage medium 903, which can also be used to implement the same inventive concept.

[0120] ​​It should be noted that the above examples are only for more clearly illustrating the technical solutions of the present application, and those skilled in the art can understand that the embodiments of the present application are not limited to the above content, and the obvious changes, replacements or substitutions based on the above content do not exceed the scope of the technical solutions of the present application; other embodiments will also fall within the scope of the present application without departing from the concept of the present application.

Claims

1. A hybrid vehicle failure diagnosis method characterized by comprising: The method comprises a first torque difference distinguishing step (100), a second air-fuel ratio distinguishing step (200); the first torque difference distinguishing step (100) obtains the current torque of the motor (600) of the hybrid vehicle (900), and if the difference between the current torque and the target torque is greater than the preset torque difference threshold, the first abnormal flag is set; the second air-fuel ratio distinguishing step (200) obtains the air-fuel ratio signal, and if the difference between the air-fuel ratio signal and the target air-fuel ratio is greater than the preset air-fuel ratio difference threshold, the second abnormal flag is set; if the first abnormal flag is set and the second abnormal flag is set at the same time, it is determined that the engine (909) of the hybrid vehicle (900) is in the off state.

2. The hybrid vehicle malfunction diagnosis method according to claim 1, wherein The air-fuel ratio signal is detected by an oxygen sensor.

3. The hybrid vehicle malfunction diagnosis method according to claim 2, wherein The air-fuel ratio signal is also compensated by fuel correction and / or air-fuel ratio filtering; the fuel correction compensation is used for part enrichment protection working condition.

4. The hybrid vehicle fault diagnosis method according to any one of claims 1 to 3 further comprises a third supercharging pressure difference distinguishing step (300); the third supercharging pressure difference distinguishing step (300) is used to confirm whether the engine (909) is in the supercharging working condition; if the engine (909) is not in the supercharging working condition, the fault diagnosis process is ended; if the engine (909) is in the supercharging working condition, a fourth pressure difference distinguishing step (400) is executed.

5. The hybrid vehicle malfunction diagnosis method according to claim 4, wherein The fourth pressure difference distinguishing step (400) obtains the current supercharging pressure of the engine (909), and if the difference between the target supercharging pressure of the engine (909) and the current supercharging pressure is greater than the preset supercharging pressure difference threshold, the third abnormal flag is set; if the first abnormal flag, the second abnormal flag and the third abnormal flag are set at the same time, it is determined that the engine (909) of the hybrid vehicle (900) is in the off state; otherwise, the engine (909) does not have the off fault.

6. The hybrid vehicle malfunction diagnosis method according to any one of claims 1 to 3 or 5, wherein: If the engine (909) exhaust catalyst temperature is greater than the preset first safety risk temperature threshold and / or the exhaust catalyst temperature is greater than the preset second temperature threshold and lasts for more than the second temperature duration, it is determined that the engine (909) of the hybrid vehicle (900) is in the off state. 7.The hybrid vehicle fault diagnosis method of claim 5, wherein: The current torque, the air-fuel ratio signal and / or the current supercharging pressure are provided by the engine management system (EMS); the first abnormal flag, the second abnormal flag and / or the third abnormal flag are transmitted to the vehicle control unit (VCU) for decision.

8. A hybrid vehicle fault diagnosis device (700) comprising a first torque difference discrimination unit (710), a second air-fuel ratio discrimination unit (720); wherein, The first torque difference distinguishing unit (710) obtains the current torque of the motor (600) of the hybrid vehicle (900), and if the difference between the current torque and the target torque is greater than the preset torque difference threshold, the first abnormal flag is set; The second air-fuel ratio distinguishing unit (720) obtains the air-fuel ratio signal, and if the difference between the air-fuel ratio signal and the target air-fuel ratio is greater than the preset air-fuel ratio difference threshold, the second abnormal flag is set; if the first abnormal flag and the second abnormal flag are set at the same time, it is determined that the engine (909) of the hybrid vehicle (900) is in the off state.

9. The hybrid vehicle failure diagnosis device (700) according to claim 8, wherein The air-fuel ratio signal is detected by an oxygen sensor.

10. The hybrid vehicle failure diagnosis device (700) according to claim 9, wherein The air-fuel ratio signal is further compensated by fuel correction and / or air-fuel ratio filtering; the fuel correction is used for part enrichment protection condition. 11.The hybrid vehicle fault diagnosis device (700) of any one of claims 8 to 10, further comprising a third pressure difference discrimination unit (730) configured to determine whether the engine (909) is in a supercharged condition; if the engine (909) is not in the supercharged condition, the fault diagnosis process is ended; if the engine (909) is in the supercharged condition, a fourth pressure difference discrimination unit (740) is started or turned on.

12. The hybrid vehicle failure diagnosis device (700) according to claim 11, wherein The fourth pressure difference discrimination unit (740) obtains a current supercharged pressure of the engine (909), and if a difference between a target supercharged pressure of the engine (909) and the current supercharged pressure is greater than a preset supercharged pressure difference threshold, a third abnormality flag is set; if the first abnormality flag is set, the second abnormality flag is set, and the third abnormality flag is set at the same time, it is determined that the engine (909) of the hybrid vehicle (900) is in an engine stall condition; otherwise, the engine (909) does not have an engine stall fault.

13. The hybrid vehicle malfunction diagnosis apparatus (700) according to any one of claims 8 to 10 or 12, wherein: If the engine (909) exhaust catalyst temperature is greater than a preset first safety risk temperature threshold and / or the exhaust catalyst temperature is greater than a preset second temperature threshold and lasts for more than a second temperature duration, it is determined that the engine (909) of the hybrid vehicle (900) is in an engine stall condition.

14. The hybrid vehicle failure diagnosis device (700) according to claim 12, wherein: The current torque, the air-fuel ratio signal, and / or the current supercharged pressure are provided by an engine management system (EMS); and the first abnormality flag, the second abnormality flag, and / or the third abnormality flag are transmitted to a vehicle control unit (VCU) for decision making. 15.A computer storage medium (903) comprising a storage medium body configured to store a computer program; the computer program, when executed by a microprocessor, implements the hybrid vehicle fault diagnosis method of any one of claims 1 to 6. 16.A controller (901) comprising the hybrid vehicle fault diagnosis device (700) of any one of claims 8 to 14 and / or the computer storage medium (903) of any one of claim 15.

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