A fault diagnosis method and device

Abstract

The application provides a fault diagnosis method and device, determines a first working mode of a hybrid vehicle at a first time, preliminarily judges the possibility of clutch sticking if the first working mode is a pure electric mode and the gear shifting force in a synchronization stage is greater than a first preset force, preliminarily judges the possibility of clutch sticking if the first working mode is a parallel mode and the gear shifting force in the synchronization stage is greater than a second preset force and / or the speed change rate of an engine is less than a first preset change rate, and preliminarily judges the possibility of clutch sticking if the first working mode is switching from the parallel mode to the pure electric mode and the speed change rate of the engine is less than a second preset change rate during engine fuel cut-off shutdown. According to the working characteristics of different modes, the application implements a suitable clutch sticking diagnosis method, can identify a smaller sticking torque, avoids irreversible damage of the clutch and even the gearbox, and improves driving safety.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of vehicles, in particular to a fault diagnosis method and device. BACKGROUND

[0002] Hybrid electric vehicles are generally divided into multiple operating modes, such as pure electric driving mode, engine-only driving mode, series driving mode, parallel driving mode, idling charging mode, etc. As a key component of the power system of a hybrid electric vehicle, the clutch plays an important role in mode switching and directly affects the driving performance and safety performance of the vehicle.

[0003] In the use of the clutch, the vehicle control logic will take various active protection measures to prevent clutch failure under different working conditions, such as start control based on adaptive adjustment of clutch torque based on actual engine response, dual-mass flywheel resonance identification protection, engine anti-flameout protection, etc. Although the active protection measures of the clutch largely avoid clutch failure, it is still impossible to completely avoid clutch failure in actual use. In order to avoid clutch failure causing clutch sticking, ablation, and even gearbox unable to shift, etc., the clutch needs to be diagnosed for failure and corresponding passive protection actions need to be performed.

[0004] The existing clutch sticking diagnosis methods are mainly divided into two categories. One is to determine that the clutch is stuck when the clutch transmission torque is lower than the engine output torque, the engine speed change rate is determined, and the engine actual speed change rate is lower than the engine theoretical speed change rate, and the engine theoretical speed change rate is obtained by the difference between the engine output torque and the clutch transmission torque divided by the engine inertia. If the vehicle is not equipped with a clutch torque sensor, the accuracy of the clutch torque obtained by the torque model is not high, so it is easy to cause misjudgment, so this method is only suitable for vehicles equipped with a clutch torque sensor. The other is to determine that the clutch is stuck when the engine torque is less than the shutdown torque and the engine speed and the clutch driven end speed difference are determined, and when the two are close, the clutch is determined to be stuck. This method can only determine the sticking torque greater than the engine friction torque and cannot identify smaller sticking torque. SUMMARY

[0005] Therefore, the purpose of the present application is to provide a fault diagnosis method and device that can diagnose clutch sticking faults with smaller sticking torque and improve driving safety. The specific solutions are as follows:

[0006] In a first aspect, the present application provides a fault diagnosis method, comprising:

[0007] determining a first working mode of a hybrid electric vehicle at a first time;

[0008] If the first working mode is the parallel mode, the clutch is opened, the gear box input shaft is shifted up, the engine is cut off, the speed is changed, and if the shifting force in the synchronization stage is greater than the second preset force and / or the rate of change of the speed of the engine is less than the first preset rate of change, it is preliminarily judged that the clutch is stuck.

[0009] If the first working mode is the parallel mode, the clutch is opened, the gear box input shaft is shifted up, the engine is cut off, the speed is changed, and if the shifting force in the synchronization stage is greater than the second preset force and / or the rate of change of the speed of the engine is less than the first preset rate of change, it is preliminarily judged that the clutch is stuck.

[0010] If the first working mode is the parallel mode, the clutch is opened, the gear box input shaft is shifted up, the engine is cut off, the speed is changed, and if the shifting force in the synchronization stage is greater than the second preset force and / or the rate of change of the speed of the engine is less than the first preset rate of change, it is preliminarily judged that the clutch is stuck.

[0011] Optionally, after the preliminary judgment that the clutch is stuck, the method further comprises:

[0012] determining a second working mode of the hybrid vehicle at a second time; the second time is later than the first time;

[0013] If the second working mode is the parallel mode, the torque of the engine and the clutch is removed, the engine is controlled to enter the idle control mode after the actual torque of the clutch is zero, and the gear box input shaft is shifted to the neutral gear; after a preset time, if the speed of the gear box input shaft is greater than a first speed, it is determined that the clutch is stuck.

[0014] If the second working mode is the parallel mode, the torque of the engine and the clutch is removed, the engine is controlled to enter the idle control mode after the actual torque of the clutch is zero, and the gear box input shaft is shifted to the neutral gear; after a preset time, if the speed of the gear box input shaft is greater than a first speed, it is determined that the clutch is stuck.

[0015] If the second working mode is the parallel mode, the torque of the engine and the clutch is removed, the engine is controlled to enter the idle control mode after the actual torque of the clutch is zero, and the gear box input shaft is shifted to the neutral gear; after a preset time, if the speed of the gear box input shaft is greater than a first speed, it is determined that the clutch is stuck.

[0016] Optionally, after the preliminary judgment that the clutch is stuck, the method further comprises:

[0017] The gear box input shaft is shifted to the neutral gear, and the vehicle is controlled to enter the pure electric driving mode.

[0018] Optionally, after the preliminary judgment that the clutch is stuck, the method further comprises:

[0019] A fault reminder of the clutch sticking is performed.

[0020] Optionally, the first preset force or the second preset force is determined according to a first working parameter at the first time, and the first working parameter comprises J, a, k, and F.Detent 、 and F ofst ; the first preset force or the second preset force is represented as:

[0021] Wherein, the J is synchronous moment of inertia; the alpha is input shaft speed variation rate converted to synchronous end; the k is friction torque and friction force conversion coefficient, determined by synchronizer parameter; the F Detent is force required to overcome resistance in gear control; the is gear mechanism efficiency; the F ofst is positive value of calibration;

[0022] The first preset variation rate or the second preset variation rate is determined according to second working parameter at first time, and the second working parameter includes T fric , J eng and omega ofst ; the first preset variation rate or the second preset variation rate is represented as: |T fric / J eng |-omega ofst ;

[0023] Wherein, the T fric is friction torque of engine, related to temperature and pump loss, obtained by engine self-learning correction; the J eng is moment of inertia of engine; the omega ofst is positive value of calibration.

[0024] In a second aspect, the embodiment of the present application further provides a fault diagnosis device, comprising:

[0025] A determination unit is configured to determine a first working mode of the hybrid vehicle at a first time;

[0026] A judgment unit is configured to preliminarily judge the possibility of clutch sticking if the first working mode is pure electric mode and the gear shifting force in the synchronization stage is greater than a first preset force; preliminarily judge the possibility of clutch sticking if the first working mode is parallel mode, the clutch is opened, the input shaft of the gearbox is upshifted, the engine is cut off, the speed is changed, and the gear shifting force in the synchronization stage is greater than a second preset force and / or the speed variation rate of the engine is less than a first preset variation rate; and preliminarily judge the possibility of clutch sticking if the first working mode is switching from parallel mode to pure electric mode, and the speed variation rate of the engine is less than a second preset variation rate during the engine cut-off shutdown process.

[0027] Optionally, the device is further configured to:

[0028] determining a second working mode of the hybrid vehicle at a second time point, the second time point being later than the first time point;

[0029] if the second working mode is the parallel mode, removing the torque of the engine and the clutch, after the actual torque of the clutch is zero, controlling the engine to enter the idle control mode, and the input shaft of the gearbox is in the neutral gear; after a preset time, if the speed of the input shaft of the gearbox is greater than the first speed, it is determined that the clutch is stuck;

[0030] if the second working mode is the pure electric mode, controlling the input shaft of the gearbox to be in the neutral gear; if the difference between the actual drop rate and the theoretical drop rate of the speed of the input shaft of the gearbox is greater than a preset difference, it is determined that the clutch is stuck;

[0031] if the second working mode is the parking mode, controlling the hybrid vehicle to enter the idle charging mode, so that the speed difference between the driving end and the driven end of the clutch is zero; removing the torque of the engine and the clutch, after the actual torque of the clutch is zero, controlling the engine speed to rise; if the torque of the engine is greater than a preset torque, it is determined that the clutch is stuck.

[0032] Optionally, the device further comprises:

[0033] the input shaft of the gearbox is in the neutral gear, and the vehicle is controlled to enter the pure electric driving mode.

[0034] Optionally, the device further comprises:

[0035] a fault reminder of the clutch sticking is performed.

[0036] Optionally, the first preset force or the second preset force is determined according to a first working parameter at the first time point, the first working parameter comprising J, α, k, F Detent 、 and F ofst ; the first preset force or the second preset force is represented as:

[0037] wherein, the J is the synchronous rotational inertia; the α is the input shaft speed change rate converted to the synchronous end; the k is the friction torque and friction force conversion coefficient, which is determined by the synchronizer parameter; the F Detent is the force required to overcome the resistance of the gear control; the η is the gear shifting mechanism efficiency; the F ofst is a positive value calibrated;

[0038] the first preset change rate or the second preset change rate is determined according to a second working parameter at the first time point, the second working parameter comprising T fric , J eng and ω ofst; the first preset change rate or the second preset change rate is represented as: |T fric / J eng |-ω ofst ;

[0039] wherein, the T fric is the friction torque of the engine, which is related to temperature and pump loss, and is obtained by engine self-learning correction; the J eng is the rotational inertia of the engine; the ω ofst is a positive value.

[0040] The embodiment of the present application provides a fault diagnosis method, determines the first working mode of the hybrid vehicle at the first moment; if the first working mode is the pure electric mode, if the shift force in the synchronization stage is greater than the first preset force, it is preliminarily judged that there is a possibility of clutch sticking; if the first working mode is the parallel mode, the clutch is controlled to be opened, the input shaft of the gearbox is controlled to be shifted up, the engine is controlled to be cut off, the speed is changed, if the shift force in the synchronization stage is greater than the second preset force and / or the speed change rate of the engine is less than the first preset change rate, it is preliminarily judged that there is a possibility of clutch sticking; if the first working mode is switched from the parallel mode to the pure electric mode, in the process of cutting off the engine and stopping, the speed change rate of the engine is less than the second preset change rate, it is preliminarily judged that there is a possibility of clutch sticking. The present application is suitable for hybrid vehicles, according to the working characteristics of different modes, the applicable clutch sticking diagnosis method is implemented and the corresponding fault protection action is performed, small sticking torque can be identified, irreversible damage of the clutch and even the gearbox can be avoided, and driving safety can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0042] Figure 1 A flow chart of a fault diagnosis method provided by the embodiment of the present application is shown;

[0043] Figure 2 A schematic diagram of a hybrid power system configuration provided by the embodiment of the present application is shown;

[0044] Figure 3 A flow chart of another fault diagnosis method provided by the embodiment of the present application is shown;

[0045] Figure 4 A flow chart of another fault diagnosis method provided by the embodiment of the present application is shown;

[0046] Figure 5 Fig. 1 shows a schematic diagram of a fault diagnosis device according to an embodiment of the present application. DETAILED DESCRIPTION

[0047] In order to make the above objectives, features and advantages of the present application more clear and comprehensible, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0048] In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present application, but the present application can also be implemented in other ways different from those described herein, and those skilled in the art can make similar generalizations without departing from the connotation of the present application, therefore the present application is not limited to the specific embodiments disclosed below.

[0049] As described in the background, the existing clutch sticking diagnosis method, one is to judge by the engine speed change rate when the clutch master and driven end slip, and to judge as sticking when the actual engine speed change rate is lower than the theoretical engine speed change rate, if the vehicle is not equipped with a clutch torque sensor, the clutch torque obtained by the torque model is not high in accuracy, so it is easy to cause misjudgment, so this method is only suitable for vehicles equipped with a clutch torque sensor; another is to judge by the difference between the engine speed and the clutch driven end speed when the clutch is opened, and to judge as sticking when the two are close, this method can only judge the sticking torque greater than the engine friction torque, and cannot identify smaller sticking torque.

[0050] Based on the above technical problems, the embodiments of the present application provide a fault diagnosis method, determining the first working mode of the hybrid vehicle at the first time; if the first working mode is the pure electric mode, if the shift force in the synchronization stage is greater than the first preset force, it is preliminarily judged that there is a possibility of clutch sticking; if the first working mode is the parallel mode, the clutch is opened, the gearbox input shaft is shifted up, the engine is cut off, the speed is changed, if the shift force in the synchronization stage is greater than the second preset force and / or the speed change rate of the engine is less than the first preset change rate, it is preliminarily judged that there is a possibility of clutch sticking; if the first working mode is switched from the parallel mode to the pure electric mode, during the engine cut-off shutdown process, the speed change rate of the engine is less than the second preset change rate, it is preliminarily judged that there is a possibility of clutch sticking. The present application is suitable for hybrid vehicles, according to the working characteristics of different modes, the applicable clutch sticking diagnosis method is implemented and the corresponding fault protection action is performed, which can identify smaller sticking torque, avoid irreversible damage to the clutch and even the gearbox, and improve driving safety.

[0051] In order to facilitate understanding, the fault diagnosis method and device provided by the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0052] Referring to Figure 1 As shown in the flowchart of a fault diagnosis method provided by the embodiment of the present application, the method can include the following steps.

[0053] S101, determine the first working mode of the hybrid vehicle at the first time.

[0054] In the embodiment of the present application, the hybrid vehicle has multiple working modes, for example, pure electric mode, parallel mode, idling charging mode, etc. When the vehicle is in pure electric mode, the vehicle is driven to travel only by relying on the driving motor, and the engine does not work; when the vehicle is in parallel mode, the driving motor and the engine jointly drive the vehicle to travel; when the vehicle is in idling charging mode, the engine outputs positive torque, and the driving motor outputs negative torque to charge the power battery.

[0055] In the embodiment of the present application, referring to Figure 2 As shown in the schematic diagram of the configuration of the hybrid power system provided by the embodiment of the present application, it includes an engine 1, a clutch 2, a first synchronizer 4, a second synchronizer 7, a transmission input shaft 9, an output shaft 11, an intermediate shaft 23, a third synchronizer 15, a main reducer 17, a driving motor 24, and transmission gears 3, 5, 6, 8, 10, 12, 13, 14, 16, 18, 19, 20, 21, 22, 25. The engine 1 and the transmission input shaft 9 are connected through the clutch 2.

[0056] In the embodiment of the present application, specifically, in the pure electric mode, the clutch 2 is opened, the engine 1 is disconnected with the transmission input shaft 9, the vehicle is driven to travel by relying on the driving motor 24, and the motor shaft (i.e. the intermediate shaft 23) and the input shaft 9 are all in gear. In the parallel mode, the clutch 2 is closed, the engine 1 and the driving motor 24 jointly drive the vehicle to travel, and the motor shaft and the input shaft 9 are all in gear. In the idling charging mode, the engine 1 torque is controlled, the motor 24 speed is controlled, the engine outputs positive torque, the motor outputs negative torque to charge the power battery, and the power transmission between the engine and the driving motor relies on the charging gear. The mechanical transmission path of the charging gear is: the clutch 2 is closed—input shaft 9—synchronizer 4 is engaged on the left—gear 3—gear 16—gear 20—intermediate shaft 23—gear 19—gear 18—gear 25.

[0057] S102, preliminarily judge whether there is a possibility of clutch sticking according to the parameters of the first working mode.

[0058] In the embodiment of the present application, according to the characteristics of different working modes, the applicable clutch sticking preliminary judgment method is implemented to preliminarily judge whether there is a possibility of clutch sticking, referring to Figure 3 The flowchart of another fault diagnosis method provided by the embodiment of the present application.

[0059] S1021, if the first working mode is pure electric mode, and if the shifting force during the synchronization phase is greater than the first preset force, it is preliminarily determined that there is a possibility of clutch sticking.

[0060] In this embodiment, when the first operating mode is pure electric mode, the clutch is open and the engine is off. This can be determined by whether the shifting force during the synchronization phase is abnormal. Specifically, if the shifting force during the synchronization phase is greater than a first preset force, it is preliminarily determined that there is a possibility of clutch sticking. The first preset force is determined based on the first operating parameters at the first moment, and the first operating parameters include J, α, k, and F. Detent , and F ofst .

[0061] This step can be expressed by the formula:

[0062]

[0063] Among them, F sync The shifting force during the synchronization phase acts on the synchronizer's shift fork; The first preset force; J is the synchronous rotational inertia; α is the rate of change of the input shaft speed converted to the synchronous end; k is the conversion coefficient between frictional torque and frictional force, determined by the synchronizer parameters; F Detent The force required to overcome the resistance of gear control; For the efficiency of the gear shifting mechanism; F ofst The positive value is determined during the actual vehicle development process.

[0064] S1022, if the first working mode is a parallel mode, the clutch is opened, the gearbox input shaft is shifted up, the engine fuel is cut off, and the speed changes. If the shifting force during the synchronization phase is greater than the second preset force and / or the engine speed change rate is less than the first preset change rate, then it is preliminarily determined that there is a possibility of clutch sticking.

[0065] In this embodiment, when the first operating mode is parallel mode, the clutch is closed and the engine is running. The engine speed change rate can be used to determine if it is abnormal. Specifically, if during upshifting at the transmission input shaft and engine fuel cut-off, the shifting force during the synchronization phase is greater than a second preset force and / or the engine speed change rate is less than a first preset change rate, then it is preliminarily determined that there is a possibility of clutch sticking. The second preset force is determined based on the first operating parameters at the first moment, which include J, α, k, and F. Detent , and F ofst The first preset rate of change is determined based on the second operating parameter at the first moment. The second operating parameter includes T. fric J eng and ω ofst .

[0066] In the embodiment of the present application, if the shift force in the synchronization stage is greater than the second preset force, it is preliminarily judged that there is a possibility of clutch sticking, and this step is expressed by a formula as follows:

[0067]

[0068] Wherein, F sync is the shift force in the synchronization stage, acting on the yoke of the synchronizer; is the second preset force; J is the synchronization rotational inertia; a is the input shaft speed change rate converted to the synchronization end; k is the friction torque and friction force conversion coefficient, determined by the synchronizer parameters; F Detent is the force required to overcome the resistance in the gear control; is the shift mechanism efficiency; F ofst is a positive value determined in real vehicle development.

[0069] In the embodiment of the present application, if the engine speed change rate is less than the first preset change rate, it is preliminarily judged that there is a possibility of clutch sticking, and this step is expressed by a formula as follows:

[0070] |ω eng |<|T fric / J eng |-ω ofst

[0071] Wherein, ω eng is the engine speed change rate in the upshift speed regulation process or the engine shutdown process; |T fric / J eng |-ω ofst is the first preset change rate; T fric is the engine friction torque, related to temperature and pump loss, obtained by engine self-learning correction; J eng is the engine rotational inertia; ω ofst is a positive value determined in calibration.

[0072] In the embodiment of the present application, if the first working mode is switched from the parallel mode to the pure electric mode, and the engine speed change rate is less than the second preset change rate during the engine fuel cut shutdown process, it is preliminarily judged that there is a possibility of clutch sticking.

[0073] In the embodiment of the present application, if the first working mode is switched from the parallel mode to the pure electric mode, and the control clutch is switched from closed to open, and the engine speed change rate is less than the second preset change rate during the engine fuel cut shutdown process, it is preliminarily judged that there is a possibility of clutch sticking. The second preset change rate is determined according to the second working parameter at the first time, and the second working parameter includes T fric and Jeng and ω ofst .

[0074] The step is expressed by the formula:

[0075] |ω eng |<|T fric / J eng |-ω ofst

[0076] Wherein, ω eng is the rate of change of engine speed during the upshift speed regulation process or the engine shutdown process; |T fric / J eng |-ω ofst is the second preset rate; T fric is the friction torque of the engine, which is related to temperature and pump loss and is obtained by self-learning correction of the engine; J eng is the rotational inertia of the engine; ω ofst is a positive value of the calibration.

[0077] S103, determining a second working mode of the hybrid vehicle at a second time, and determining whether clutch sticking occurs according to parameters of the second working mode.

[0078] In the embodiments of the present application, after preliminarily judging the possibility of clutch sticking, whether clutch sticking occurs is determined according to parameters in different working modes by using corresponding clutch sticking diagnosis methods, for reference Figure 4 is a flowchart of another fault diagnosis method provided in the embodiments of the present application.

[0079] S1031, if the second working mode is the parallel mode, the torque of the engine and the clutch is removed, and after the actual torque of the clutch is zero, the engine is controlled to enter the idle control mode and the input shaft of the gearbox is shifted to the neutral gear; after a preset time, if the speed of the input shaft of the gearbox is greater than a first speed, it is determined that the clutch is stuck.

[0080] In the embodiments of the present application, when the vehicle is in the running state, if the current is the parallel mode, the torque of the engine and the clutch needs to be removed, the clutch is controlled to be opened, and after the actual torque of the clutch is zero, the engine is controlled to enter the idle control mode and the input shaft is shifted to the neutral gear. After a preset time, if the speed of the input shaft of the gearbox cannot drop below the first speed, it is determined that the clutch is stuck. The actual torque of the clutch is calculated by a clutch torque model,

[0081] S1032, if the second working mode is the pure electric mode, the input shaft of the gearbox is controlled to be shifted to the neutral gear; if the difference between the actual drop rate and the theoretical drop rate of the speed of the input shaft of the gearbox is greater than a preset difference, it is determined that the clutch is stuck.

[0082] In the embodiment of the present application, if the second working mode is the pure electric mode, the clutch is in the open state, the engine is in the stopped state, the engine speed is zero, the input shaft is controlled to be in the neutral state, after the input shaft is in the neutral state, the actual speed drop rate of the input shaft is tested in the process of the speed drop of the input shaft, and is compared with the theoretical speed drop rate, if the difference between the actual speed drop rate and the theoretical speed drop rate is greater than the preset difference, it is determined that the clutch is stuck.

[0083] The formula of the step is:

[0084] |ω 实际 |-|ω 理论 |>ω0

[0085] Wherein, ω 实际 is the actual speed drop rate of the input shaft of the gearbox, ω 理论 is the theoretical speed drop rate of the input shaft of the gearbox, which is determined by the drag torque and the moment of inertia of the input shaft and the driven disc of the clutch in the neutral state, and is obtained by trial development, and ω0 is the preset difference, which is a positive value.

[0086] In S1033, if the second working mode is the parking mode, the hybrid vehicle is controlled to enter the idle charging mode, the speed difference between the driving end and the driven end of the clutch is zero, the torque of the engine and the clutch is removed, after the actual torque of the clutch is zero, the engine speed is controlled to rise, and if the torque of the engine is greater than the preset torque, it is determined that the clutch is stuck.

[0087] In the embodiment of the present application, when the vehicle is in the parking state, the clutch needs to be closed, the engine is started by using the charging gear, the vehicle enters the idle charging mode, the clutch is in the closed state, the engine torque is controlled, and the motor speed is controlled, at this time, the speed difference between the driving end and the driven end of the clutch is zero, then the torque of the clutch and the engine is removed, the clutch is controlled to be opened, after the actual torque calculated by the clutch torque model is zero, the engine speed is controlled to be synchronized with the input shaft speed, then the engine torque is controlled to rise at an interval of 1 Nm each time, until the obvious speed difference between the driving end and the driven end of the clutch appears, if the torque of the engine is greater than the preset torque, it is determined that the clutch is stuck, and the torque of the engine at this time is recorded as the sticking torque of the clutch.

[0088] In the embodiment of the present application, after it is determined that the clutch is stuck, the input shaft of the gearbox can be controlled to be in the neutral state, and the vehicle is controlled to enter the pure electric driving mode.

[0089] In the embodiment of the present application, after it is determined that the clutch is stuck, the clutch sticking fault is reminded. Specifically, the hybrid fault light is lighted in the instrument panel, the clutch sticking fault is recorded, and the driver is reminded to repair as soon as possible.

[0090] The embodiment of the present application provides a fault diagnosis method, determines a first working mode of a hybrid vehicle at a first moment; if the first working mode is a pure electric mode, if a gear shifting force in a synchronization stage is greater than a first preset force, it is preliminarily judged that there is a possibility of clutch sticking; if the first working mode is a parallel mode, the clutch is controlled to be opened, the input shaft of the gearbox is controlled to be shifted up, the engine is controlled to be cut off, the speed is changed, if the gear shifting force in the synchronization stage is greater than a second preset force and / or the speed change rate of the engine is less than a first preset change rate, it is preliminarily judged that there is a possibility of clutch sticking; if the first working mode is switching from the parallel mode to the pure electric mode, in the process of cutting off the engine and stopping the engine, the speed change rate of the engine is less than a second preset change rate, it is preliminarily judged that there is a possibility of clutch sticking. The present application is suitable for a hybrid vehicle, according to the working characteristics of different modes, a suitable clutch sticking diagnosis method is implemented and a corresponding fault protection action is performed, small sticking torque can be identified, irreversible damage of the clutch and even the gearbox can be avoided, and driving safety is improved.

[0091] Based on the above fault diagnosis method, the embodiment of the present application further provides a fault diagnosis device, as shown in the reference Figure 5 The fault diagnosis device provided by the embodiment of the present application can comprise:

[0092] The determination unit 100 is used for determining a first working mode of a hybrid vehicle at a first moment.

[0093] The judgment unit 200 is used for if the first working mode is a pure electric mode, if a gear shifting force in a synchronization stage is greater than a first preset force, it is preliminarily judged that there is a possibility of clutch sticking; if the first working mode is a parallel mode, the clutch is controlled to be opened, the input shaft of the gearbox is controlled to be shifted up, the engine is controlled to be cut off, the speed is changed, if the gear shifting force in the synchronization stage is greater than a second preset force and / or the speed change rate of the engine is less than a first preset change rate, it is preliminarily judged that there is a possibility of clutch sticking; if the first working mode is switching from the parallel mode to the pure electric mode, in the process of cutting off the engine and stopping the engine, the speed change rate of the engine is less than a second preset change rate, it is preliminarily judged that there is a possibility of clutch sticking.

[0094] Optionally, the fault diagnosis device is further used for determining a second working mode of the hybrid vehicle at a second moment; the second moment is later than the first moment;

[0095] If the second working mode is a parallel mode, the torque of the engine and the clutch is removed, after the actual torque of the clutch is zero, the engine is controlled to enter an idle control mode, and the input shaft of the gearbox is controlled to be in a neutral gear; after a preset time, if the speed of the input shaft of the gearbox is greater than a first speed, it is determined that the clutch is stuck;

[0096] If the second working mode is the pure electric mode, the gearbox input shaft is controlled to be in the neutral gear; if the difference between the actual drop rate and the theoretical drop rate of the rotation speed of the gearbox input shaft is greater than a preset difference, it is determined that the clutch is stuck;

[0097] If the second working mode is the parking mode, the hybrid vehicle is controlled to enter the idle charging mode, the rotation speed difference between the driving end and the driven end of the clutch is zero; the torque of the engine and the clutch is removed, and after the actual torque of the clutch is zero, the rotation speed of the engine is controlled to rise; if the torque of the engine is greater than a preset torque, it is determined that the clutch is stuck.

[0098] Optionally, the fault diagnosis device is further used to control the vehicle to enter the pure electric driving mode with the gearbox input shaft in the neutral gear.

[0099] Optionally, the fault diagnosis device is further used to perform the fault warning of the clutch sticking.

[0100] The embodiment of the present application provides a fault diagnosis device, a determination unit is used to determine the first working mode of a hybrid vehicle at a first time; a judgment unit is used to preliminarily judge that there is a possibility of clutch sticking if the first working mode is the pure electric mode and the shift force in the synchronization stage is greater than a first preset force; the judgment unit is used to preliminarily judge that there is a possibility of clutch sticking if the first working mode is the parallel mode, the clutch is controlled to be opened, the gearbox input shaft is controlled to be shifted up, the engine is controlled to be cut off, the rotation speed is changed, and the shift force in the synchronization stage is greater than a second preset force and / or the rotation speed change rate of the engine is less than a first preset change rate; the judgment unit is used to preliminarily judge that there is a possibility of clutch sticking if the first working mode is the switching from the parallel mode to the pure electric mode, and the rotation speed change rate of the engine is less than a second preset change rate during the engine cut-off shutdown process. The present application is suitable for the hybrid vehicle, different mode working characteristics are used to implement the applicable clutch sticking diagnosis method and perform the corresponding fault protection action, the small sticking torque can be identified, the irreversible damage of the clutch and even the gearbox can be avoided, and the driving safety can be improved.

[0101] Each of the embodiments in the specification is described in a progressive manner, and the same and similar parts of each of the embodiments can be referred to each other. Each of the embodiments mainly describes the difference from other embodiments. Especially, the device embodiment is described relatively simply because it is basically similar to the method embodiment, and the related parts can be referred to the part of the method embodiment.

[0102] The above description is only the preferred embodiment of the present application, although the present application has been disclosed as above with the preferred embodiment, however, not to limit the present application. Any skilled person in the art, without departing from the scope of the technical scheme of the present application, can utilize the above disclosed methods and technical contents to make many possible changes and modifications to the technical scheme of the present application, or modify as equivalent embodiments of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application, without departing from the content of the technical scheme of the present application, still belongs to the scope of protection of the technical scheme of the present application.

Claims

1. A fault diagnosis method, characterized in that, include: Determine the first operating mode of the hybrid vehicle at the first moment; If the first working mode is pure electric mode, and if the shifting force during the synchronization phase is greater than the first preset force, it is preliminarily determined that there is a possibility of clutch sticking. If the first working mode is the parallel mode, the clutch is opened, the gearbox input shaft is upshifted, the engine fuel is cut off, and the speed changes. If the shifting force during the synchronization phase is greater than the second preset force and / or the engine speed change rate is less than the first preset change rate, it is preliminarily judged that there is a possibility of clutch sticking. If the first working mode is a switch from parallel mode to pure electric mode, and the engine speed change rate is less than the second preset change rate during the engine fuel cut-off shutdown process, it is preliminarily judged that there is a possibility of clutch sticking.

2. The method according to claim 1, characterized in that, After initially determining the possibility of clutch sticking, the method further includes: Determine the second operating mode of the hybrid vehicle at a second time point; the second time point is later than the first time point. If the second working mode is parallel mode, the torque of the engine and clutch is removed. After the actual torque of the clutch is zero, the engine is controlled to enter the idle speed control mode and the transmission input shaft is shifted to neutral. After a preset time, if the speed of the transmission input shaft is greater than the first speed, the clutch is determined to be stuck. If the second working mode is pure electric mode, control the transmission input shaft to shift to neutral; if the difference between the actual rate of decrease of the transmission input shaft speed and the theoretical rate of decrease is greater than a preset difference, determine that the clutch is stuck. If the second working mode is the parking mode, control the hybrid vehicle to enter the idle charging mode so that the speed difference between the clutch driving end and the driven end is zero; remove the torque of the engine and the clutch, and after the actual torque of the clutch is zero, control the engine speed to increase; if the engine torque is greater than the preset torque, determine that the clutch is stuck.

3. The method according to claim 2, characterized in that, After determining that the clutch is stuck, the method further includes: The transmission input shaft shifts to neutral, controlling the vehicle to enter pure electric driving mode.

4. The method according to claim 2 or 3, characterized in that, After determining that the clutch is stuck, the method further includes: Provides a fault alert for clutch sticking.

5. The method according to any one of claims 1-3, characterized in that, The first preset force or the second preset force is determined based on the first working parameters at the first moment, wherein the first working parameters include J, α, k, and F. Detent η and F ofst The first preset force or the second preset force is expressed as: (J*α / k+F) Detent ) / η+F ofst ; Wherein, J is the synchronous rotational inertia; α is the rate of change of input shaft speed converted to the synchronous end; k is the conversion coefficient between frictional torque and frictional force, determined by the synchronizer parameters; and F... Detent The force required to overcome the resistance of in-gear control; η is the efficiency of the shifting mechanism; F ofst The value is a positive value as specified in the calibration. The first preset rate of change or the second preset rate of change is determined based on a second operating parameter at a first time point, wherein the second operating parameter includes T. fric J eng and ω ofst The first preset rate of change or the second preset rate of change is expressed as: |T fric / J eng |-ω ofst ; Wherein, the T fric The friction torque of the engine is related to temperature and pumping losses, and is obtained through engine self-learning correction; the J... eng The moment of inertia of the engine; the ω ofst The value is a positive value as specified in the calibration.

6. A fault diagnosis device, characterized in that, include: A determining unit is used to determine the first operating mode of the hybrid vehicle at the first moment. The judgment unit is configured to: if the first operating mode is pure electric mode, and the shifting force during the synchronization phase is greater than a first preset force, then preliminarily determine that there is a possibility of clutch sticking; if the first operating mode is parallel mode, and the clutch is opened, the transmission input shaft is upshifted, the engine fuel is cut off, and the engine speed changes, and the shifting force during the synchronization phase is greater than a second preset force and / or the engine speed change rate is less than a first preset change rate, then preliminarily determine that there is a possibility of clutch sticking; if the first operating mode is a switch from parallel mode to pure electric mode, and the engine speed change rate is less than a second preset change rate during the engine fuel cut-off shutdown process, then preliminarily determine that there is a possibility of clutch sticking.

7. The apparatus according to claim 6, characterized in that, The device is also used for: Determine the second operating mode of the hybrid vehicle at a second time point; the second time point is later than the first time point. If the second working mode is the parallel mode, the torque of the engine and clutch is removed. After the actual torque of the clutch is zero, the engine is controlled to enter the idle speed control mode and the transmission input shaft is shifted to neutral. If, after a preset time, the speed of the gearbox input shaft is greater than the first speed, then clutch sticking is determined. If the second operating mode is pure electric mode, control the gearbox input shaft to shift to neutral; If the difference between the actual rate of decrease of the speed of the gearbox input shaft and the theoretical rate of decrease is greater than the preset difference, clutch sticking is determined. If the second working mode is the parking mode, control the hybrid vehicle to enter the idle charging mode so that the speed difference between the clutch driving end and the driven end is zero; remove the torque of the engine and the clutch, and after the actual torque of the clutch is zero, control the engine speed to increase; if the engine torque is greater than the preset torque, determine that the clutch is stuck.

8. The apparatus according to claim 7, characterized in that, The device further includes: The transmission input shaft shifts to neutral, controlling the vehicle to enter pure electric driving mode.

9. The apparatus according to claim 7 or 8, characterized in that, The device further includes: Provides a fault alert for clutch sticking.

10. The apparatus according to any one of claims 6-8, characterized in that, The first preset force or the second preset force is determined based on the first working parameters at the first moment, wherein the first working parameters include J, α, k, and F. Detent η and F ofst The first preset force or the second preset force is expressed as: (J*α / k+F) Detent ) / η+F ofst ; Wherein, J is the synchronous rotational inertia; α is the rate of change of input shaft speed converted to the synchronous end; k is the conversion coefficient between frictional torque and frictional force, determined by the synchronizer parameters; and F... Detent The force required to overcome the resistance of in-gear control; η is the efficiency of the shifting mechanism; F ofst The value is a positive value as specified in the calibration. The first preset rate of change or the second preset rate of change is determined based on a second operating parameter at a first time point, wherein the second operating parameter includes T. fric J eng and ω ofst The first preset rate of change or the second preset rate of change is expressed as: |T fric / J eng |-ω ofst ; Wherein, the T fric The friction torque of the engine is related to temperature and pumping losses, and is obtained through engine self-learning correction; the J... eng The moment of inertia of the engine; the ω ofst The value is a positive value as specified in the calibration.

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