Sliding friction control method of hydraulic torque converter and related device

Abstract

The invention discloses a sliding friction control method of a hydraulic torque converter and a related device, and if the vehicle speed is smaller than a preset vehicle speed threshold value, a gearbox is in a gear shifting process, and a lock-up clutch of the hydraulic torque converter is in a lock-up state, the torque capacity of the lock-up clutch of the hydraulic torque converter is controlled to be reduced based on a first torque rate. And if the difference value between the torque capacity of the hydraulic torque converter lock-up clutch and the engine torque is smaller than or equal to the first torque threshold value, target feed-forward control torque is determined according to the engine torque request value, the target turbine rotating speed and the target speed difference of the engine, and the hydraulic torque converter lock-up clutch is controlled based on the target feed-forward torque. Therefore, in different stages of gear shifting, the torque capacity of the lock-up clutch of the hydraulic torque converter is controlled in a self-adaptive mode, so that slip frequency needed by different stages is generated, incomplete locking of the hydraulic torque converter is achieved, vibration and noise of a transmission system can be reduced, and fuel economy and driving smoothness can be effectively considered.

Description

Technical Field

[0001] The present invention relates to the field of vehicle control technology, and in particular to a slip control method and related device for a hydraulic torque converter. Background Art

[0002] The hydraulic torque converter, also known as the torque converter, is an improvement on the hydraulic coupling and is used to transmit rotational power. It connects the power source (usually an engine or motor) with the working machine and can act as a clutch like the hydraulic coupling. The hydraulic torque converter can change the size of the torque.

[0003] The automatic transmission with a torque converter can transmit power through the hydraulic transmission and friction transmission of the torque converter, which can greatly improve the transmission efficiency and has good anti-vibration and buffering performance. In medium and high speed conditions, the torque converter is generally fully locked through the locking clutch, thereby improving the transmission efficiency of the automatic transmission and improving the fuel economy of the vehicle. Figure 1 shown.

[0004] However, when the vehicle is running at a low speed, if there is a powered upshift, the clutch needs to be involved, which can easily cause a shock to the entire vehicle that the driver can feel. Summary of the invention

[0005] In view of the above problems, the present application provides a slip and friction control method and related device of a torque converter, which are used to avoid the driver's perceptible vehicle impact caused by the clutch being involved in the operation during low-speed operation of the vehicle.

[0006] Based on this, the embodiments of the present application disclose the following technical solutions:

[0007] On the one hand, an embodiment of the present application provides a slip control method for a torque converter, the method comprising:

[0008] Obtain the vehicle speed, the state of the transmission and the state of the torque converter lock-up clutch;

[0009] If the vehicle speed is less than a preset vehicle speed threshold, the transmission is in a gear shift process, and the torque converter lockup clutch is in a locked state, the torque capacity of the torque converter lockup clutch is controlled to decrease based on a first torque rate;

[0010] Get engine torque;

[0011] If the difference between the torque capacity of the torque converter lockup clutch and the engine torque is less than or equal to a first torque threshold, obtaining an engine torque request value, a target turbine speed, and a target speed difference of the engine;

[0012] determining a target feedforward control torque according to the engine torque request value, the target turbine speed, and a target speed difference of the engine;

[0013] The torque converter lockup clutch is controlled based on the target feed-forward torque.

[0014] Optionally, after the gear shifting process is completed, the method further includes:

[0015] Determining a feedforward torque growth rate according to the speed difference, speed difference change rate, engine torque and sliding friction work of the engine;

[0016] The state of the torque converter lockup clutch is restored to a locked state based on the feed-forward torque increase rate.

[0017] Optionally, if the vehicle speed is less than a preset vehicle speed threshold, the transmission is in a gear shifting process, and the torque converter lockup clutch is in a locked state, the method further includes:

[0018] controlling a torque capacity of the torque converter lockup clutch to decrease based on a second torque rate, the second torque rate being greater than the first torque rate;

[0019] Get engine torque;

[0020] The step of controlling the torque capacity of the torque converter lockup clutch to decrease based on the first torque rate is performed if the difference between the torque capacity of the torque converter lockup clutch and the engine torque is less than or equal to a second torque threshold, the second torque threshold being greater than the first torque threshold.

[0021] Optionally, if the difference between the torque capacity of the torque converter lockup clutch and the engine torque is less than or equal to a first torque threshold, obtaining the engine torque request value, the target turbine speed and the target speed difference of the engine includes:

[0022] If the difference between the torque capacity of the torque converter lockup clutch and the engine torque is less than or equal to the first torque threshold and the shift process is in a torque phase, controlling the change in the torque capacity of the torque converter lockup clutch based on the change in the engine torque;

[0023] If the shift process is in the speed phase, an engine torque request value, a target turbine speed, and a target speed difference of the engine are obtained.

[0024] Optionally, determining the target feedforward control torque according to the engine torque request value, the target turbine speed and the target speed difference of the engine includes:

[0025] The target feedforward control torque is calculated according to the engine torque request value, the target turbine speed and the target speed difference of the engine, and the calculation method is as follows:

[0026]

[0027] Among them, T FF is the target feedforward control torque, T EngReq is the engine torque request value, J e is the engine inertia, n TgtTurb is the target turbine speed, C is the capacity characteristic coefficient of the torque converter lockup clutch, n TgtSlip is the target speed difference of the engine.

[0028] Optionally, controlling the torque converter lockup clutch based on the target feed-forward torque includes:

[0029] Obtaining an actual speed difference of the engine;

[0030] If the actual speed difference of the engine and the target speed difference of the engine are less than or equal to a preset speed difference threshold, controlling the torque converter lockup clutch based on the target feed-forward torque;

[0031] If the actual speed difference of the engine and the target speed difference of the engine are greater than the preset speed difference threshold, controlling the torque converter lockup clutch based on the target feedforward torque and the target feedback torque;

[0032] The target feedback torque is determined as follows:

[0033] Get the proportional coefficient and integral coefficient;

[0034] The difference of the deviation values ​​is adjusted according to the proportional coefficient, and the deviation value of the current cycle is adjusted according to the integral coefficient to obtain a feedback torque change rate, wherein the difference of the deviation values ​​is the difference between the deviation value of the current cycle and the deviation value of the previous cycle, and the deviation value is the difference between the actual speed difference of the engine and the target speed difference of the engine;

[0035] The torque of this cycle is determined according to the change rate of the feedback torque and the torque of the previous cycle, and the torque of this cycle is used as the target feedback torque.

[0036] Optionally, if the vehicle speed is less than a preset vehicle speed threshold, the transmission is in a gear shifting process, and the torque converter lockup clutch is in a locked state, controlling the torque capacity of the torque converter lockup clutch to decrease based on a first torque rate includes:

[0037] If the vehicle speed is less than a preset vehicle speed threshold, the transmission is in a gear shifting process, the torque converter lockup clutch is in a locked state, and an activation condition is satisfied, the torque capacity of the torque converter lockup clutch is controlled to decrease based on a first torque rate,

[0038] Among them, the activation conditions include one or more combinations of the following: there is no fault code in the automatic transmission control unit, the oil temperature of the automatic transmission is lower than a preset oil temperature threshold, the engine torque is lower than a preset torque threshold, the driving mode is in the forward gear, the slip work of the torque converter lockup clutch is lower than a preset slip work threshold, and the time used for the gear shifting process does not exceed a preset time threshold.

[0039] On the other hand, the present application provides a slip control device for a hydraulic torque converter, the device comprising: an acquisition unit, a control unit, and a determination unit;

[0040] The acquisition unit is used to acquire the vehicle speed, the state of the transmission and the state of the torque converter lockup clutch;

[0041] the control unit is configured to control the torque capacity of the torque converter lockup clutch to decrease based on a first torque rate if the vehicle speed is less than a preset vehicle speed threshold, the transmission is in a gear shifting process, and the torque converter lockup clutch is in a locked state;

[0042] The acquisition unit is further used to acquire engine torque;

[0043] The acquisition unit is further configured to acquire an engine torque request value, a target turbine speed, and a target speed difference of the engine if a difference between a torque capacity of the torque converter lockup clutch and the engine torque is less than or equal to a first torque threshold;

[0044] The determination unit is configured to determine a target feedforward control torque according to the engine torque request value, the target turbine speed, and a target speed difference of the engine;

[0045] The control unit is further configured to control the torque converter lockup clutch based on the target feed-forward torque.

[0046] Optionally, after the gear shifting process is completed, the determining unit is further used to determine the feedforward torque growth rate according to the speed difference, speed difference change rate, engine torque and sliding friction work of the engine;

[0047] The control unit is further configured to restore the state of the torque converter lockup clutch to a locked state based on the feedforward torque increase rate.

[0048] Optionally, if the vehicle speed is less than a preset vehicle speed threshold, the transmission is in a gear shifting process, and the torque converter lockup clutch is in a locked state, the control unit is further configured to control the torque capacity of the torque converter lockup clutch to decrease based on a second torque rate, the second torque rate being greater than the first torque rate;

[0049] The acquisition unit is further used to acquire engine torque;

[0050] The control unit is further configured to execute the step of controlling the torque capacity of the torque converter lockup clutch to decrease based on the first torque rate if the difference between the torque capacity of the torque converter lockup clutch and the engine torque is less than or equal to a second torque threshold, and the second torque threshold is greater than the first torque threshold.

[0051] Optionally, the control unit is further configured to control the change in the torque capacity of the torque converter lockup clutch based on the change in the engine torque if the difference between the torque capacity of the torque converter lockup clutch and the engine torque is less than or equal to the first torque threshold and the shift process is in a torque phase;

[0052] The acquisition unit is further configured to acquire the engine torque request value, the target turbine speed and the target speed difference of the engine if the difference between the torque capacity of the torque converter lockup clutch and the engine torque is less than or equal to the first torque threshold and the shift process is in the speed phase.

[0053] Optionally, the determining unit is specifically configured to:

[0054] The target feedforward control torque is calculated according to the engine torque request value, the target turbine speed and the target speed difference of the engine, and the calculation method is as follows:

[0055]

[0056] Among them, T FF is the target feedforward control torque, T EngReq is the engine torque request value, J e is the engine inertia, n TgtTurb is the target turbine speed, C is the capacity characteristic coefficient of the torque converter lockup clutch, n TgtSlip is the target speed difference of the engine.

[0057] Optionally, the acquisition unit is further used to acquire an actual speed difference of the engine;

[0058] The control unit is further configured to control the torque converter lockup clutch based on the target feedforward torque if the actual speed difference of the engine and the target speed difference of the engine are less than or equal to a preset speed difference threshold;

[0059] The control unit is further configured to control the torque converter lockup clutch based on the target feedforward torque and the target feedback torque if the actual speed difference of the engine and the target speed difference of the engine are greater than the preset speed difference threshold;

[0060] The device further comprises a target feedback torque determination unit, which is used to:

[0061] Get the proportional coefficient and integral coefficient;

[0062] The difference of the deviation values ​​is adjusted according to the proportional coefficient, and the deviation value of the current cycle is adjusted according to the integral coefficient to obtain a feedback torque change rate, wherein the difference of the deviation values ​​is the difference between the deviation value of the current cycle and the deviation value of the previous cycle, and the deviation value is the difference between the actual speed difference of the engine and the target speed difference of the engine;

[0063] The torque of this cycle is determined according to the change rate of the feedback torque and the torque of the previous cycle, and the torque of this cycle is used as the target feedback torque.

[0064] Optionally, the control unit is further configured to control the torque capacity of the torque converter lockup clutch to decrease based on the first torque rate if the vehicle speed is less than a preset vehicle speed threshold, the transmission is in a gear shifting process, the torque converter lockup clutch is in a locked state, and an activation condition is met,

[0065] Among them, the activation conditions include one or more combinations of the following: there is no fault code in the automatic transmission control unit, the oil temperature of the automatic transmission is lower than a preset oil temperature threshold, the engine torque is lower than a preset torque threshold, the driving mode is in the forward gear, the slip work of the torque converter lockup clutch is lower than a preset slip work threshold, and the time used for the gear shifting process does not exceed a preset time threshold.

[0066] In another aspect, the present application provides a computer device, the device comprising a processor and a memory:

[0067] The memory is used to store program code and transmit the program code to the processor;

[0068] The processor is used to execute the method described in the above aspects according to the instructions in the program code.

[0069] On the other hand, the present application provides a computer-readable storage medium, wherein the computer-readable storage medium is used to store a computer program, and the computer program is used to execute the method described in the above aspects.

[0070] On the other hand, an embodiment of the present application provides a computer program product or a computer program, which includes computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device executes the method described in the above aspects.

[0071] The advantages of the above technical solution of this application are:

[0072] The vehicle speed, the state of the transmission and the state of the torque converter lockup clutch are obtained. If the vehicle speed is less than the preset speed threshold, the transmission is in the gear shifting process, and the torque converter lockup clutch is in the locked state, it means that the vehicle needs to perform a gear shift operation during low-speed operation, and the torque converter is completely locked. In order to avoid the driver from feeling the impact of the entire vehicle, the torque capacity of the torque converter lockup clutch is controlled to decrease based on the first torque rate so that the torque converter lockup clutch produces slip friction, so that the torque converter starts to open from being completely locked. When the torque capacity of the torque converter lockup clutch drops rapidly to near the engine torque, that is, if the difference between the torque capacity of the torque converter lockup clutch and the engine torque is less than or equal to the first torque threshold, the turbine speed changes rapidly at this time, which is more likely to cause impact. In order to ensure that the torque capacity of the torque converter lockup clutch can follow the changes in the engine torque and the torque converter can achieve incomplete locking, the target feedforward control torque is determined according to the engine torque request value, the target turbine speed and the target speed difference of the engine, and the torque converter lockup clutch is controlled based on the target feedforward torque. At this time, the slip generated by the torque converter lockup clutch is larger, and part of the vibration and impact can be absorbed based on hydraulic transmission.

[0073] Therefore, at different stages of the gear shift, the torque capacity of the torque converter lockup clutch is adaptively controlled to generate the slip required at different stages, achieve incomplete locking of the torque converter, reduce the vibration and noise of the transmission system, and avoid the driver's perceptible vehicle impact caused by the clutch participating in the operation during low-speed operation of the vehicle. In addition, the slip of the torque converter lockup clutch during the slip-friction control process is very small, and the friction loss is also very small, which can effectively take into account both fuel economy and driving smoothness. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0075] Figure 1 A schematic diagram of the automatic transmission system matching the torque converter;

[0076] Figure 2 A flow chart of a slip control method for a hydraulic torque converter provided in the present application;

[0077] Figure 3 A schematic diagram of a slip control process of a hydraulic torque converter provided in the present application;

[0078] Figure 4 A schematic diagram of clutch balance of a hydraulic torque converter provided in an embodiment of the present application;

[0079] Figure 5 A schematic diagram of a slip control device for a hydraulic torque converter provided in the present application;

[0080] Figure 6 A structural diagram of a computer device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0081] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0082] Combine the following Figure 2 , a slip control method for a hydraulic torque converter provided in an embodiment of the present application is introduced. Figure 2 , this figure is a flow chart of a slip control method for a torque converter provided in an embodiment of the present application, and the method may include S201-S206. Figure 2 The method shown, in one implementation, may be executed by, for example, an electronic control unit (ECU) included in a vehicle.

[0083] S201: Obtain the vehicle speed, the state of the transmission and the state of the torque converter lockup clutch.

[0084] Among them, the vehicle speed is used to identify the speed of the vehicle during operation, which can be obtained based on sensor acquisition. The state of the gearbox is used to identify whether the vehicle is in a gear shift state, which can be obtained based on the driver's operation signal on the handle. The state of the torque converter lockup clutch is used to identify whether the torque converter lockup clutch is in a locked state, which can be obtained based on sensor acquisition, such as judging whether the torque converter lockup clutch is closed based on the position information collected by the position sensor, or judging whether the torque converter lockup clutch is closed based on the pressure information collected by the pressure sensor.

[0085] S202: If the vehicle speed is less than a preset vehicle speed threshold, the transmission is in a gear shifting process, and the torque converter lockup clutch is in a locked state, the torque capacity of the torque converter lockup clutch is controlled to decrease based on a first torque rate.

[0086] Based on the preset vehicle speed threshold, the vehicle speed can be limited to low speed. If the vehicle speed is less than the preset vehicle speed threshold, it means that the vehicle is running at low speed. The gearbox is in the process of shifting, which means that the vehicle is in the process of shifting. If the torque converter lockup clutch is in the locked state, it means that the torque converter is completely locked.

[0087] If the vehicle speed is less than the preset vehicle speed threshold, the gearbox is in the process of shifting, and the torque converter lockup clutch is in the locked state, the clutch is in the process of working, which is likely to cause the driver to feel the impact of the whole vehicle. Based on this, the embodiment of the present application controls the torque capacity of the torque converter lockup clutch during the shifting process to achieve the slip of the torque converter lockup clutch, thereby achieving incomplete locking of the torque converter based on slip control, avoiding causing the driver to feel the impact of the whole vehicle.

[0088] In addition, some other activation conditions can also be detected, such as hardware protection, timeout protection and other strategies. When the other conditions are met, it means that the vehicle state and the driver are more likely to feel the impact of the whole vehicle. Some activation conditions are explained below.

[0089] (1) There is no fault code inside the automatic transmission control unit, indicating that the vehicle's operation is safe and reliable.

[0090] (2) The oil temperature of the automatic transmission is lower than the preset oil temperature threshold. If the oil temperature of the automatic transmission is high, the torque converter lockup clutch may not be released, thereby causing the torque converter friction control method provided in the embodiment of the present application to fail to release the torque converter. This condition belongs to the hardware protection strategy.

[0091] (3) The engine torque is less than the preset torque threshold. If the engine torque is too high, the torque converter lockup clutch may not be released, which may result in the torque converter slip control method provided in the embodiment of the present application failing to release the torque converter. This condition belongs to the hardware protection strategy.

[0092] (4) The driving mode is in the forward gear, such as D or S, which can ensure the normal operation of the vehicle.

[0093] (5) The target gear is within a certain range, that is, the gear that the driver expects to be engaged (target gear) can keep the vehicle at a low speed.

[0094] (6) The slip work of the torque converter lockup clutch is less than the preset slip work threshold. This item belongs to the hardware protection strategy.

[0095] (7) If the time taken for the gear shifting process does not exceed the preset time threshold, it means that the vehicle has not triggered the timeout protection strategy and normal gear shifting can be achieved.

[0096] After the condition of controlling the torque capacity of the torque converter lockup clutch is met, that is, if the vehicle speed is less than the preset vehicle speed threshold, the gearbox is in the gear shifting process, and the torque converter lockup clutch is in the locked state, the torque capacity of the torque converter lockup clutch is controlled to decrease based on the first torque rate. Among them, the torque capacity refers to the ability of the friction plate in the torque converter to transmit torque. Controlling the torque capacity of the torque converter lockup clutch to decrease based on the first torque rate can reduce the pressure on the torque converter lockup clutch and achieve a small friction of the torque converter lockup clutch, so that the torque converter lockup clutch produces slip friction, so that the torque converter starts to open from fully locked, thereby making the torque capacity of the torque converter lockup clutch quickly drop to near the engine torque, so that the torque capacity control of the torque converter lockup clutch in the subsequent speed phase can respond quickly.

[0097] Among them, the movement process of the torque converter lockup clutch is divided into the torque phase stage and the speed phase stage. In the torque phase stage, the target speed difference of the torque converter lockup clutch gradually transitions from zero to the torque phase speed difference setting value. Since the torque converter will be subjected to higher pressure when fully locked, such as 5 Nm of force can make the torque converter lockup clutch completely locked, but in actual application, in order to make the torque converter lockup clutch closed, 7 Nm of force may be used, and the excess 2 Nm of force is called the lockup safety margin. Therefore, the control goal of the torque converter lockup clutch is first to reduce the lockup safety margin and achieve a small slip of the lockup clutch, so that the torque capacity control of the lockup clutch in the speed phase can respond quickly.

[0098] As a possible implementation method, in order to make the torque capacity of the torque converter lock-up clutch faster and better controlled, the torque phase of the torque converter lock-up clutch can be divided into three stages for separate control. Figure 3 Please explain in detail.

[0099] Phase 1: Control the torque capacity of the torque converter lockup clutch to decrease based on the second torque rate, wherein the second torque rate is greater than the first torque rate. The engine torque can be continuously obtained, that is, the difference between the torque capacity of the torque converter lockup clutch and the engine torque is monitored until the difference between the torque capacity of the torque converter lockup clutch and the engine torque is less than or equal to the second torque threshold, then entering phase 2.

[0100] Wherein, the second torque threshold (such as Figure 3 Thrsh1 in (i) is greater than the first torque threshold (i.e. Figure 3 Thrsh2) in the stage 1, that is, in stage 1, the torque capacity of the torque converter lockup clutch is controlled to decrease rapidly at a faster rate in order to eliminate the lockup safety margin of the torque converter lockup clutch.

[0101] Stage 2: Based on the first torque rate, the torque capacity of the torque converter lockup clutch is controlled to decrease, and the engine torque can be continuously obtained, that is, the difference between the torque capacity of the torque converter lockup clutch and the engine torque is monitored until the difference between the torque capacity of the torque converter lockup clutch and the engine torque is less than or equal to the first torque threshold, then the stage 3 or the speed phase stage can be entered.

[0102] It should be noted that the first torque rate and the second torque rate can both be determined based on the speed difference between the oil temperature, the engine speed and the turbine speed, and the second torque rate is greater than the first torque rate, or in other words, the torque capacity of the torque converter lockup clutch decreased based on the second torque rate is faster than the torque capacity of the torque converter lockup clutch decreased based on the first torque rate. Thus, the torque capacity of the torque converter lockup clutch can be controlled to decrease quickly first and then decrease at a slower speed, such as Figure 3 The stages ① and ② are shown so that the torque capacity of the torque converter lock-up clutch can be reduced to the first torque threshold more quickly and stably.

[0103] As a possible implementation method, not only can the stage three or the speed phase stage be entered when the difference between the torque capacity of the torque converter lockup clutch and the engine torque is less than or equal to the first torque threshold, but the stage three or the speed phase stage can also be entered when the deviation value between the speed difference between the engine speed and the turbine speed and the target speed difference of the torque converter lockup clutch is greater than a preset threshold.

[0104] It is understandable that after the difference between the torque capacity of the torque converter lockup clutch and the engine torque is less than or equal to the first torque threshold, due to the delay, after a period of time, the deviation value between the speed difference between the engine speed and the turbine speed and the target speed difference of the torque converter lockup clutch will be greater than the preset threshold. In order to avoid the situation where, due to parts failure and the like, although the difference between the torque capacity of the torque converter lockup clutch and the engine torque is less than or equal to the first torque threshold, the deviation value between the speed difference between the engine speed and the turbine speed and the target speed difference of the torque converter lockup clutch cannot be greater than the preset threshold, it can be directly based on the deviation value between the speed difference between the engine speed and the turbine speed and the target speed difference of the torque converter lockup clutch being greater than the preset threshold, to determine whether to enter stage three or the speed phase stage.

[0105] Phase 3: If the difference between the torque capacity of the torque converter lockup clutch and the engine torque is less than or equal to the first torque threshold, and the current shift process is in the torque phase, the torque capacity change of the torque converter lockup clutch is controlled based on the change in the engine torque, such as Figure 3 In stage ③ shown, the change in engine torque per cycle is the change in torque capacity per cycle.

[0106] S203: Obtain engine torque.

[0107] As a possible implementation, the engine torque may be acquired in real time to monitor whether the difference between the torque capacity of the torque converter lock-up clutch and the engine torque is less than or equal to the first torque threshold.

[0108] S204: If the difference between the torque capacity of the torque converter lock-up clutch and the engine torque is less than or equal to the first torque threshold, the engine torque request value, the target turbine speed, and the target speed difference of the engine are obtained.

[0109] After the driver issues a shift command, the shift clutch issues signals such as the engine request torque value and the turbine speed target change rate based on the shift command. The engine torque request value is the torque value that the engine should reach based on the driver's command, the target turbine speed is the speed that the turbine should reach based on the driver's command, and the target speed difference of the engine is the speed difference that the engine should reach based on the driver's command.

[0110] It is understandable that after the torque capacity of the torque converter lockup clutch is decreased based on the first torque rate control, that is, after the adjustment based on S202, the difference between the torque capacity of the torque converter lockup clutch and the engine torque is less than or equal to the first torque threshold, at which time, the current shift process may still be in the torque phase, or change from the torque phase to the speed phase. Among them, it can be determined based on the signal sent by the transmission whether the current shift process is in the speed phase or the torque phase.

[0111] If the engine is still in the torque phase after the adjustment based on S202, it corresponds to the aforementioned phase 3. If the engine enters the speed phase after the adjustment based on S202. It should be noted that after the adjustment based on S202, the engine may first enter the aforementioned phase 3, and then enter the speed phase. Thus, the engine torque request value, target turbine speed, and target speed difference of the engine may be obtained by only detecting whether the shift process is in the speed phase.

[0112] In the speed phase stage, the target speed difference of the torque converter lockup clutch gradually transitions from the current speed difference to the speed phase speed difference setting value. It should be noted that the speed phase turbine speed changes rapidly, and it is easy to produce impact when the turbine speed begins to change and is about to synchronize. In order for the torque capacity of the torque converter lockup clutch to follow the engine torque change, so that the torque converter can achieve incomplete locking, the speed phase stage is compared with the torque phase stage. The target slip should be larger, thereby relying on the hydraulic transmission of the torque converter to absorb some vibrations and impacts. S205: Determine the target feedforward control torque based on the engine torque request value, the target turbine speed and the target speed difference of the engine.

[0113] As a possible implementation method, in the speed phase, continue to refer to Figure 3 If there is no shift request, the engine torque will always change based on the implementation. If there is a shift request, the engine torque will change to the dotted line. Therefore, the torque capacity of the torque converter lockup clutch needs to be consistent with the engine torque change, so as to follow the engine torque change. Compared with the torque phase, the torque capacity of the torque converter lockup clutch needs to be finely controlled in the speed phase, which can be achieved based on feedforward control, as described below.

[0114] See also Figure 4 , which is a schematic diagram of a clutch balance of a torque converter provided in an embodiment of the present application. If the engine is analyzed based on the torque balance of the torque converter lockup clutch, it can be obtained that:

[0115]

[0116] Among them, T Eng is the engine torque, J e is the engine inertia, n Eng is the engine speed, T Hydr is the torque of the hydraulic lock-up clutch of the torque converter, T Clch It is the theoretical value of the torque capacity of the torque converter lock-up clutch.

[0117] Based on the characteristics of the torque converter lock-up clutch, formula (2) can be obtained:

[0118] T Hydr = Cn Eng 2 (2)

[0119] Among them, T Hydr is the torque of the hydraulic lockup clutch of the torque converter, C is the capacity characteristic coefficient of the hydraulic lockup clutch of the torque converter, n Eng is the engine speed.

[0120] Combining formula (1) and (2), the theoretical value of the torque capacity of the locking clutch can be expressed as formula (3):

[0121]

[0122] Among them, T Clch is the theoretical value of the torque capacity of the torque converter lock-up clutch, T Eng is the engine torque, J e is the engine inertia, n Eng is the engine speed, and C is the capacity characteristic coefficient of the torque converter lock-up clutch.

[0123] Based on the engine request torque and turbine speed target change rate signals sent by the shift clutch in real time, the target control speed of the torque converter lockup clutch can be set. The target feedforward torque of the torque converter lockup clutch is obtained from formula (3), which can be expressed as formula (4):

[0124]

[0125] Among them, T FF is the target feed-forward torque of the torque converter lock-up clutch, T EngReq is the engine torque request value, J e is the engine inertia, n TgtTurb is the target turbine speed, C is the capacity characteristic coefficient of the torque converter lockup clutch, n TgtSlip is the target speed difference of the engine.

[0126] Therefore, when it is recognized that the gearbox is in the process of shifting, the torque converter lockup clutch is controlled based on the different torque capacities of the shifting stage, thereby generating slip in a timely manner, realizing the slip and friction control of the torque converter, and helping to improve the drivability of the entire vehicle.

[0127] S206: Controlling the torque converter lockup clutch based on the target feed-forward torque.

[0128] As a possible implementation method, it is based only on feedforward control, which may cause errors. It can be continuously adjusted based on feedback control, which is explained in detail below in conjunction with S2061-S2063.

[0129] S2061: Obtaining the actual speed difference of the engine.

[0130] S2062: If the actual speed difference of the engine and the target speed difference of the engine are less than or equal to the preset speed difference threshold, the torque converter lockup clutch is controlled based on the target feedforward torque.

[0131] S2063: If the actual speed difference of the engine and the target speed difference of the engine are greater than a preset speed difference threshold, the torque converter lockup clutch is controlled based on the target feedforward torque and the target feedback torque.

[0132] Therefore, if the actual speed difference of the engine and the target speed difference of the engine are less than or equal to the preset speed difference threshold, it means that the error of the torque converter lockup clutch controlled based on the feedforward torque is still within the allowable range, and the torque converter lockup clutch can be controlled based on the target feedforward torque. If the actual speed difference of the engine and the target speed difference of the engine are greater than the preset speed difference threshold, it means that the error of the torque converter lockup clutch controlled based on the feedforward torque is no longer within the allowable range, and the torque converter lockup clutch needs to be controlled based on the target feedforward torque and the target feedback torque.

[0133] The following describes how to determine the target feedback torque through S1-S3.

[0134] S1: Get the proportional coefficient and integral coefficient.

[0135] The proportional coefficient (P parameter) refers to the coefficient required for proportional control in PID (proportional-integral-differential) control, and the integral coefficient (I parameter) refers to the coefficient required for integral control in PID control. As a possible implementation method, incremental PI control can be used to achieve the target slip. As a possible implementation method, the PI parameters are obtained based on the speed difference and the speed difference change rate, and the PI parameters are set separately in different shifting stages.

[0136] As a possible implementation, the feedback is not cleared during a single gear shift. For example, when the gear shift slip control starts, the counter starts counting and stops counting after the gear shift is completed.

[0137] S2: The difference of the deviation value is adjusted according to the proportional coefficient, and the deviation value of this cycle is adjusted according to the integral coefficient to obtain the feedback torque change rate.

[0138] The difference in the deviation value is the difference between the deviation value of the current cycle and the deviation value of the previous cycle, and the deviation value is the difference between the actual speed difference of the engine and the target speed difference of the engine.

[0139] S3: Determine the torque of this cycle according to the change rate of the feedback torque and the torque of the previous cycle, and use the torque of this cycle as the target feedback torque.

[0140] As a possible implementation method, it can be expressed by formulas (5)-(7):

[0141] err(k)=n ActSlip (k)-n TgtSlip (k) (5)

[0142] ΔT FB (k) = k p *[err(k)-err(k-1)]+k i *err(k) (6)

[0143] T FB (k) = T FB (k-1)+ΔT FB (k) (7)

[0144] Among them, n ActSlip is the actual speed difference of the engine, n TgtSlip is the target speed difference of the engine, k is the current cycle, k-1 is the previous cycle, err(k) is the deviation value of the current cycle, err(k-1) is the deviation value of the previous cycle, k p is the proportionality coefficient, k i is the integration coefficient, ΔT FB (k) is the feedback torque change rate, T FB (k-1) is the torque of the previous cycle, T FB (k) is the torque of this cycle.

[0145] The torque capacity of the torque converter lock-up clutch can be expressed as the sum of the feedforward torque and the feedback torque, as shown in formula (8):

[0146] T Clch =T FF +T FB (8)

[0147] Among them, T Clch is the theoretical value of the torque capacity of the torque converter lock-up clutch, T FF is the target feedforward torque, T FB is the target feedback torque.

[0148] It can be seen from the above technical solution that the vehicle speed, the state of the gearbox and the state of the torque converter lockup clutch are obtained. If the vehicle speed is less than the preset speed threshold, the gearbox is in the gear shifting process, and the torque converter lockup clutch is in the locked state, it means that the vehicle needs to perform a gear shift operation during low-speed operation, and the torque converter is completely locked. In order to avoid the driver from feeling the impact of the entire vehicle, the torque capacity of the torque converter lockup clutch is controlled to decrease based on the first torque rate so that the torque converter lockup clutch produces slip friction, so that the torque converter starts to open from being completely locked. When the torque capacity of the torque converter lockup clutch drops rapidly to near the engine torque, that is, if the difference between the torque capacity of the torque converter lockup clutch and the engine torque is less than or equal to the first torque threshold, the turbine speed changes rapidly at this time, which is more likely to cause impact. In order to ensure that the torque capacity of the torque converter lockup clutch can follow the changes in the engine torque and the torque converter can achieve incomplete locking, the target feedforward control torque is determined according to the engine torque request value, the target turbine speed and the target speed difference of the engine, and the torque converter lockup clutch is controlled based on the target feedforward torque. At this time, the slip generated by the torque converter lockup clutch is larger, and part of the vibration and impact can be absorbed based on hydraulic transmission.

[0149] Therefore, at different stages of the gear shift, the torque capacity of the torque converter lockup clutch is adaptively controlled to generate the slip required at different stages, achieve incomplete locking of the torque converter, reduce the vibration and noise of the transmission system, and avoid the driver's perceptible vehicle impact caused by the clutch participating in the operation during low-speed operation of the vehicle. In addition, the slip of the torque converter lockup clutch during the slip-friction control process is very small, and the friction loss is also very small, which can effectively take into account both fuel economy and driving smoothness.

[0150] In addition, as a possible implementation method, after the gear shift process is completed, that is, after the gear shift is completed, the moment when the torque converter lockup clutch is fully locked again may cause impact. Therefore, in order to avoid the vehicle impact that the driver can feel, it is necessary to ensure that the torque converter lockup clutch smoothly returns to the locked state. The following is combined with S207 and S208 ( Figure 2 Detailed description is given in detail (not shown).

[0151] S207: After the gear shifting process is completed, the feedforward torque growth rate is determined according to the speed difference of the engine, the speed difference change rate, the engine torque and the sliding friction work.

[0152] For example, the basic speed difference can be determined based on the speed difference of the engine and the speed difference change rate, and then the feedforward torque growth rate can be determined based on the basic speed difference, the engine torque and the sliding friction work. The determination method can be a table lookup method. The sliding friction work can be determined based on the target torque of the torque converter, the speed difference of the engine speed and the turbine speed.

[0153] S208: Restoring the state of the torque converter lockup clutch to the locked state based on the feedforward torque increase rate.

[0154] After the gear shift is completed, the lockup clutch begins to resume locking, and the target speed difference gradually transitions to zero. Figure 3 In stage ⑤, the state of the torque converter lockup clutch is restored to the locked state based on the feedforward torque growth rate to achieve a smooth transition.

[0155] In order to make the technical solution provided by the embodiment of the present application clearer, Figure 3 The slip control method of the torque converter provided in the embodiment of the present application is described.

[0156] exist Figure 3 In the transmission, the vehicle is running at a low speed and shifting from 3rd gear to 4th gear, the torque converter lockup clutch is in a locked state.

[0157] Stage ①: Based on the second torque rate, the torque capacity of the torque converter lockup clutch is controlled to decrease until the difference between the torque capacity of the torque converter lockup clutch and the engine torque is less than or equal to the second torque threshold, and then the stage ② is entered. Thus, the torque capacity of the torque converter lockup clutch is rapidly reduced.

[0158] Stage ②: Based on the first torque rate, the torque capacity of the torque converter lockup clutch is controlled to decrease until the difference between the torque capacity of the torque converter lockup clutch and the engine torque is less than or equal to the first torque threshold, and then the stage ③ is entered. Thus, the torque capacity of the torque converter lockup clutch is steadily reduced.

[0159] Phase ③: Based on the change in engine torque, the torque capacity of the torque converter lockup clutch is controlled until the speed phase is entered. Thus, the torque capacity of the torque converter lockup clutch can change with the engine torque, so as to respond quickly in the speed phase.

[0160] Stage ④: If the actual speed difference of the engine and the target speed difference of the engine are less than or equal to the preset speed difference threshold, the torque converter lockup clutch is controlled based on the target feedforward torque; if the actual speed difference of the engine and the target speed difference of the engine are greater than the preset speed difference threshold, the torque converter lockup clutch is controlled based on the target feedforward torque and the target feedback torque so that the torque capacity of the torque converter lockup clutch can change with the engine torque.

[0161] Phase ⑤: After the gear shifting process is completed, the state of the torque converter lockup clutch is restored to the locked state based on the feedforward torque growth rate to ensure smooth gear shifting.

[0162] In addition to the slip control method of the hydraulic torque converter provided in the embodiment of the present application, a slip control device of the hydraulic torque converter is also provided, such as Figure 5 As shown, it includes: an acquisition unit 501, a control unit 502 and a determination unit 503;

[0163] The acquisition unit 501 is used to acquire the vehicle speed, the state of the gearbox and the state of the torque converter lockup clutch;

[0164] The control unit 502 is configured to control the torque capacity of the torque converter lockup clutch to decrease based on a first torque rate if the vehicle speed is less than a preset vehicle speed threshold, the transmission is in a gear shifting process, and the torque converter lockup clutch is in a locked state;

[0165] The acquisition unit 501 is also used to acquire engine torque;

[0166] The acquisition unit 501 is further configured to acquire an engine torque request value, a target turbine speed, and a target speed difference of the engine if the difference between the torque capacity of the torque converter lockup clutch and the engine torque is less than or equal to a first torque threshold;

[0167] The determination unit 503 is used to determine a target feedforward control torque according to the engine torque request value, the target turbine speed and the target speed difference of the engine;

[0168] The control unit 502 is further configured to control the torque converter lockup clutch based on the target feed-forward torque.

[0169] It can be seen from the above technical solution that the vehicle speed, the state of the gearbox and the state of the torque converter lockup clutch are obtained. If the vehicle speed is less than the preset speed threshold, the gearbox is in the gear shifting process, and the torque converter lockup clutch is in the locked state, it means that the vehicle needs to perform a gear shift operation during low-speed operation, and the torque converter is completely locked. In order to avoid the driver from feeling the impact of the entire vehicle, the torque capacity of the torque converter lockup clutch is controlled to decrease based on the first torque rate so that the torque converter lockup clutch produces slip friction, so that the torque converter starts to open from being completely locked. When the torque capacity of the torque converter lockup clutch drops rapidly to near the engine torque, that is, if the difference between the torque capacity of the torque converter lockup clutch and the engine torque is less than or equal to the first torque threshold, the turbine speed changes rapidly at this time, which is more likely to cause impact. In order to ensure that the torque capacity of the torque converter lockup clutch can follow the changes in the engine torque and the torque converter can achieve incomplete locking, the target feedforward control torque is determined according to the engine torque request value, the target turbine speed and the target speed difference of the engine, and the torque converter lockup clutch is controlled based on the target feedforward torque. At this time, the slip generated by the torque converter lockup clutch is larger, and part of the vibration and impact can be absorbed based on hydraulic transmission.

[0170] Therefore, at different stages of the gear shift, the torque capacity of the torque converter lockup clutch is adaptively controlled to generate the slip required at different stages, achieve incomplete locking of the torque converter, reduce the vibration and noise of the transmission system, and avoid the driver's perceptible vehicle impact caused by the clutch participating in the operation during low-speed operation of the vehicle. In addition, the slip of the torque converter lockup clutch during the slip-friction control process is very small, and the friction loss is also very small, which can effectively take into account both fuel economy and driving smoothness.

[0171] As a possible implementation, after the gear shift process is completed, the determination unit 503 is further used to determine the feedforward torque growth rate according to the speed difference, speed difference change rate, engine torque and sliding friction work of the engine;

[0172] The control unit 502 is further configured to restore the state of the torque converter lockup clutch to a locked state based on the feedforward torque increase rate.

[0173] As a possible implementation, if the vehicle speed is less than a preset vehicle speed threshold, the transmission is in a gear shifting process, and the torque converter lockup clutch is in a locked state, the control unit 502 is further configured to control the torque capacity of the torque converter lockup clutch to decrease based on a second torque rate, and the second torque rate is greater than the first torque rate;

[0174] The acquisition unit 501 is also used to acquire engine torque;

[0175] The control unit 502 is also used to execute the step of controlling the torque capacity of the torque converter lockup clutch to decrease based on the first torque rate if the difference between the torque capacity of the torque converter lockup clutch and the engine torque is less than or equal to a second torque threshold, and the second torque threshold is greater than the first torque threshold.

[0176] As a possible implementation, the control unit 502 is further configured to control the change in the torque capacity of the torque converter lockup clutch based on the change in the engine torque if the difference between the torque capacity of the torque converter lockup clutch and the engine torque is less than or equal to the first torque threshold and the shift process is in a torque phase;

[0177] The acquisition unit 501 is further configured to acquire the engine torque request value, the target turbine speed and the target speed difference of the engine if the gear shift process is in the speed phase.

[0178] As a possible implementation manner, the determining unit 503 is specifically configured to:

[0179] The target feedforward control torque is calculated according to the engine torque request value, the target turbine speed and the target speed difference of the engine, and the calculation method is as follows:

[0180]

[0181] Among them, T FF is the target feedforward control torque, T EngReq is the engine torque request value, J e is the engine inertia, n TgtTurb is the target turbine speed, C is the capacity characteristic coefficient of the torque converter lockup clutch, n TgtSlip is the target speed difference of the engine.

[0182] As a possible implementation, the acquisition unit 501 is further used to acquire the actual speed difference of the engine;

[0183] The control unit 502 is further configured to control the torque converter lockup clutch based on the target feedforward torque if the actual speed difference of the engine and the target speed difference of the engine are less than or equal to a preset speed difference threshold;

[0184] The control unit 502 is further configured to control the torque converter lockup clutch based on the target feedforward torque and the target feedback torque if the actual speed difference of the engine and the target speed difference of the engine are greater than the preset speed difference threshold;

[0185] The device further comprises a target feedback torque determination unit, which is used to:

[0186] Get the proportional coefficient and integral coefficient;

[0187] The difference of the deviation values ​​is adjusted according to the proportional coefficient, and the deviation value of the current cycle is adjusted according to the integral coefficient to obtain a feedback torque change rate, wherein the difference of the deviation values ​​is the difference between the deviation value of the current cycle and the deviation value of the previous cycle, and the deviation value is the difference between the actual speed difference of the engine and the target speed difference of the engine;

[0188] The torque of this cycle is determined according to the change rate of the feedback torque and the torque of the previous cycle, and the torque of this cycle is used as the target feedback torque.

[0189] As a possible implementation, the control unit 502 is further configured to control the torque capacity of the torque converter lockup clutch to decrease based on the first torque rate if the vehicle speed is less than a preset vehicle speed threshold, the transmission is in a gear shifting process, the torque converter lockup clutch is in a locked state, and an activation condition is met.

[0190] Among them, the activation conditions include one or more combinations of the following: there is no fault code in the automatic transmission control unit, the oil temperature of the automatic transmission is lower than a preset oil temperature threshold, the engine torque is lower than a preset torque threshold, the driving mode is in the forward gear, the slip work of the torque converter lockup clutch is lower than a preset slip work threshold, and the time used for the gear shifting process does not exceed a preset time threshold.

[0191] The present application also provides a computer device, see Figure 6 , which shows a structural diagram of a computer device provided in an embodiment of the present application, such as Figure 6 As shown, the device includes a memory 610 and a processor 620:

[0192] The memory 610 is used to store program codes and transmit the program codes to the processor;

[0193] The processor 620 is used to execute any one of the torque converter slip control methods provided in the above embodiments according to the instructions in the program code.

[0194] An embodiment of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium is used to store a computer program, wherein the computer program is used to execute any one of the torque converter slip control methods provided in the above embodiments.

[0195] The embodiment of the present application also provides a computer program product or a computer program, which includes a computer instruction stored in a computer-readable storage medium. The processor of the computer device reads the computer instruction from the computer-readable storage medium, and the processor executes the computer instruction, so that the computer device executes the slip control method of the hydraulic torque converter provided in various optional implementations of the above aspects.

[0196] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the various embodiments can be referred to each other. For the system or device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description.

[0197] It should be understood that in the present application, "at least one (item)" means one or more, and "plurality" means two or more. "And / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally indicates that the objects associated before and after are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or multiple.

[0198] It should also be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0199] The steps of the method or algorithm described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0200] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for controlling sliding friction of a torque converter, characterized in that: The method comprises: Obtain the vehicle speed, the state of the transmission and the state of the torque converter lock-up clutch; If the vehicle speed is less than a preset vehicle speed threshold, the transmission is in a gear shift process, and the torque converter lockup clutch is in a locked state, the torque capacity of the torque converter lockup clutch is controlled to decrease based on a first torque rate; Get engine torque; If the difference between the torque capacity of the torque converter lockup clutch and the engine torque is less than or equal to a first torque threshold, obtaining an engine torque request value, a target turbine speed, and a target speed difference of the engine; determining a target feedforward control torque according to the engine torque request value, the target turbine speed, and a target speed difference of the engine; The torque converter lockup clutch is controlled based on the target feed-forward torque.

2. The method according to claim 1, characterized in that After the gear shifting process is completed, the method further includes: Determining a feedforward torque growth rate according to the speed difference, speed difference change rate, engine torque and sliding friction work of the engine; The state of the torque converter lockup clutch is restored to a locked state based on the feed-forward torque increase rate.

3. The method according to claim 1, characterized in that If the vehicle speed is less than a preset vehicle speed threshold, the transmission is in a gear shifting process, and the torque converter lockup clutch is in a locked state, the method further includes: controlling a torque capacity of the torque converter lockup clutch to decrease based on a second torque rate, the second torque rate being greater than the first torque rate; Get engine torque; The step of controlling the torque capacity of the torque converter lockup clutch to decrease based on the first torque rate is performed if the difference between the torque capacity of the torque converter lockup clutch and the engine torque is less than or equal to a second torque threshold, the second torque threshold being greater than the first torque threshold.

4. The method according to claim 1, characterized in that If the difference between the torque capacity of the torque converter lockup clutch and the engine torque is less than or equal to a first torque threshold, obtaining an engine torque request value, a target turbine speed, and a target speed difference of the engine includes: If the difference between the torque capacity of the torque converter lockup clutch and the engine torque is less than or equal to the first torque threshold and the shift process is in a torque phase, controlling the change in the torque capacity of the torque converter lockup clutch based on the change in the engine torque; If the shift process is in the speed phase, an engine torque request value, a target turbine speed, and a target speed difference of the engine are obtained.

5. The method according to claim 1, characterized in that The determining the target feedforward control torque according to the engine torque request value, the target turbine speed and the target speed difference of the engine includes: The target feedforward control torque is calculated according to the engine torque request value, the target turbine speed and the target speed difference of the engine, and the calculation method is as follows: Among them, T FF is the target feedforward control torque, T EngReq is the engine torque request value, J e is the engine inertia, n TgtTurb is the target turbine speed, C is the capacity characteristic coefficient of the torque converter lockup clutch, n TgtSlip is the target speed difference of the engine.

6. The method according to claim 1, characterized in that The controlling the torque converter lockup clutch based on the target feed-forward torque comprises: Obtaining an actual speed difference of the engine; If the actual speed difference of the engine and the target speed difference of the engine are less than or equal to a preset speed difference threshold, controlling the torque converter lockup clutch based on the target feed-forward torque; If the actual speed difference of the engine and the target speed difference of the engine are greater than the preset speed difference threshold, controlling the torque converter lockup clutch based on the target feedforward torque and the target feedback torque; The target feedback torque is determined as follows: Get the proportional coefficient and integral coefficient; The difference of the deviation values ​​is adjusted according to the proportional coefficient, and the deviation value of the current cycle is adjusted according to the integral coefficient to obtain a feedback torque change rate, wherein the difference of the deviation values ​​is the difference between the deviation value of the current cycle and the deviation value of the previous cycle, and the deviation value is the difference between the actual speed difference of the engine and the target speed difference of the engine; The torque of this cycle is determined according to the change rate of the feedback torque and the torque of the previous cycle, and the torque of this cycle is used as the target feedback torque.

7. The method according to any one of claims 1 to 6, characterized in that: If the vehicle speed is less than a preset vehicle speed threshold, the transmission is in a gear shifting process, and the torque converter lockup clutch is in a locked state, the torque capacity of the torque converter lockup clutch is controlled to decrease based on a first torque rate, including: If the vehicle speed is less than a preset vehicle speed threshold, the transmission is in a gear shifting process, the torque converter lockup clutch is in a locked state, and an activation condition is satisfied, the torque capacity of the torque converter lockup clutch is controlled to decrease based on a first torque rate, Among them, the activation conditions include one or more combinations of the following: there is no fault code in the automatic transmission control unit, the oil temperature of the automatic transmission is lower than a preset oil temperature threshold, the engine torque is lower than a preset torque threshold, the driving mode is in the forward gear, the slip work of the torque converter lockup clutch is lower than a preset slip work threshold, and the time used for the gear shifting process does not exceed a preset time threshold.

8. A friction control device for a hydraulic torque converter, characterized in that: The device comprises: an acquisition unit, a control unit and a determination unit; The acquisition unit is used to acquire the vehicle speed, the state of the transmission and the state of the torque converter lockup clutch; the control unit is configured to control the torque capacity of the torque converter lockup clutch to decrease based on a first torque rate if the vehicle speed is less than a preset vehicle speed threshold, the transmission is in a gear shifting process, and the torque converter lockup clutch is in a locked state; The acquisition unit is further used to acquire engine torque; The acquisition unit is further configured to acquire an engine torque request value, a target turbine speed, and a target speed difference of the engine if a difference between a torque capacity of the torque converter lockup clutch and the engine torque is less than or equal to a first torque threshold; The determination unit is configured to determine a target feedforward control torque according to the engine torque request value, the target turbine speed, and a target speed difference of the engine; The control unit is further configured to control the torque converter lockup clutch based on the target feed-forward torque.

9. A computer device, characterized in that: The device comprises a processor and a memory: The memory is used to store program code and transmit the program code to the processor; The processor is used to execute the method according to any one of claims 1 to 7 according to the instructions in the program code.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium is used to store a computer program, and the computer program is used to execute the method according to any one of claims 1 to 7.

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