Mode switching method, apparatus and system, and vehicle

Abstract

A mode switching method, apparatus and system, and a vehicle, belonging to the technical field of vehicle control. In response to a mode switching request of switching from a series mode to a direct drive mode, a target electric motor rotational speed and a target electric motor torque of a first electric motor are determined, a clutch is kept in a closed state, and an engine is kept in a driving state; the first electric motor can be adjusted on the basis of the target electric motor rotational speed and the target electric motor torque; and then when a gearbox meets a gear shift condition, the gearbox is controlled to be switched to a target gear corresponding to the direct drive mode, such that the vehicle is switched from the series mode to the direct drive mode. The rotational speed and torque of a first electric motor are adjusted, such that during mode switching, there is no need to open and close a clutch, and then after a gearbox completes gear shifting, an engine can quickly output the torque without power interruption, thereby effectively improving the dynamic response performance of a vehicle.

Description

Mode switching method, device, system and vehicle

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the China Patent Office on December 8, 2023, with application number 202311687833.5 and application name “A mode switching method, device, system and vehicle”, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of vehicle control technology, and in particular to a mode switching method, device, system and vehicle. Background Art

[0004] With the rapid development of the automotive industry and in response to national policies on energy conservation, emission reduction, and carbon neutrality, traditional fuel vehicles are gradually transitioning to hybrid vehicles. To adapt to different road conditions and driving requirements, hybrid vehicles typically feature multiple driving modes, including series and direct drive.

[0005] In related technologies, when the driver deeply depresses the accelerator to accelerate, the vehicle switches from series mode to direct drive mode. At this point, the vehicle must first open the clutch, then reduce engine torque and regulate engine speed. After these operations are complete, the clutch must be re-engaged to complete the mode switch. However, this method, due to the clutch opening and closing process, not only results in a long switching link and mode switching time, but also leads to engine power interruption and delayed power response, which in turn affects the vehicle's dynamic response performance. Summary of the Invention

[0006] The present application provides a mode switching method, device, system and vehicle to solve the problem of poor vehicle dynamic response performance during the switching process from series mode to direct drive mode in current hybrid vehicles.

[0007] In order to solve the above problems, this application adopts the following technical solutions:

[0008] In a first aspect, an embodiment of the present application provides a mode switching method, the method comprising:

[0009] In response to a mode switch request from the series mode to the direct drive mode, determining a target motor speed and a target motor torque for the first motor, and maintaining a clutch in a closed state and an engine in a driving state; wherein the first motor is connected to the engine via the clutch;

[0010] Based on the target motor speed and the target motor torque, adjusting the first motor so that the transmission meets a preset shift condition;

[0011] When the gearbox meets the shifting condition, the gearbox is controlled to switch to the target gear corresponding to the direct drive mode, so that the vehicle switches from the series mode to the direct drive mode.

[0012] In one embodiment of the present application, the step of determining the target motor speed and target motor torque of the first motor includes:

[0013] determining a target motor speed of the first motor based on a current wheel speed of a target wheel and a gear ratio between the target wheel and a transmission input shaft;

[0014] The inverse of the current output torque of the engine is determined as the target motor torque of the first motor.

[0015] In one embodiment of the present application, the step of adjusting the first motor based on the target motor speed and the target motor torque so that the transmission meets a preset shift condition includes:

[0016] Based on the target motor speed, adjusting the current motor speed of the first motor;

[0017] When the current motor speed satisfies a preset torque adjustment condition, torque adjustment is performed on the current motor torque of the first motor based on the target motor torque, so that the transmission satisfies a preset shifting condition.

[0018] In one embodiment of the present application, the step of performing torque adjustment on the current motor torque of the first motor based on the target motor torque includes:

[0019] Based on the fluctuation amplitude of the current output torque of the engine, the target motor torque is corrected in real time to obtain a corrected target motor torque;

[0020] Based on the corrected target motor torque, torque adjustment is performed on the current motor torque of the first motor.

[0021] In one embodiment of the present application, after the step of adjusting the current motor speed of the first motor based on the target motor speed, the method further includes:

[0022] In a case where a first speed difference between the target motor speed and the current motor speed is less than a first speed threshold, it is determined that the current motor speed meets the torque adjustment condition.

[0023] In one embodiment of the present application, after the step of performing torque adjustment on the current motor torque of the first motor based on the target motor torque, the method further includes:

[0024] When the absolute value of the sum of the current motor torque and the current output torque of the engine is less than a torque threshold, the first speed difference between the target motor speed and the current motor speed is less than a second speed threshold, and the duration for which the first speed difference is less than the second speed threshold is greater than a duration threshold, it is determined that the gearbox meets the shifting condition.

[0025] In one embodiment of the present application, the method further includes:

[0026] When the first speed difference is less than the first speed threshold, the transmission is controlled to perform a synchronizer pre-synchronization operation to move the shift fork of the synchronizer to a target fork position.

[0027] In a second aspect, based on the same inventive concept, an embodiment of the present application provides a mode switching device, the device comprising:

[0028] a parameter determination module for determining a target motor speed and a target motor torque of a first motor in response to a mode switch request from a series mode to a direct drive mode, and maintaining a clutch in a closed state and an engine in a driving state; wherein the first motor is connected to the engine via the clutch;

[0029] a motor adjustment module, configured to adjust the first motor based on the target motor speed and the target motor torque so that the gearbox meets a preset shift condition;

[0030] A mode switching module is used to control the transmission to switch to the target gear corresponding to the direct drive mode when the transmission meets the shifting condition, so that the vehicle switches from the series mode to the direct drive mode.

[0031] In one embodiment of the present application, the parameter determination module includes:

[0032] a motor speed determination submodule, configured to determine a target motor speed of the first motor based on a current wheel speed of a target wheel and a speed ratio between the target wheel and a gearbox input shaft;

[0033] The motor torque determination submodule is configured to determine the inverse of the current output torque of the engine as the target motor torque of the first motor.

[0034] In one embodiment of the present application, the motor adjustment module includes:

[0035] a speed regulating submodule, configured to regulate the current motor speed of the first motor based on the target motor speed;

[0036] The torque adjustment submodule is used to adjust the current motor torque of the first motor based on the target motor torque when the current motor speed meets the preset torque adjustment condition, so that the gearbox meets the preset shifting condition.

[0037] In one embodiment of the present application, the torque adjustment submodule includes:

[0038] a torque correction unit, configured to correct the target motor torque in real time based on a fluctuation amplitude of the current output torque of the engine to obtain a corrected target motor torque;

[0039] The torque adjustment unit is configured to adjust the current motor torque of the first motor based on the corrected target motor torque.

[0040] In one embodiment of the present application, the mode switching device further includes:

[0041] The torque adjustment condition determination module is configured to determine that the current motor speed satisfies the torque adjustment condition when a first speed difference between the target motor speed and the current motor speed is less than a first speed threshold.

[0042] In one embodiment of the present application, the mode switching device further includes:

[0043] a gear shift condition determination module, configured to determine that the gearbox satisfies the gear shift condition when an absolute value of a sum of the current motor torque and the current output torque of the engine is less than a torque threshold, a first speed difference between the target motor speed and the current motor speed is less than a second speed threshold, and a duration for which the first speed difference is less than the second speed threshold is greater than a duration threshold.

[0044] In one embodiment of the present application, the mode switching device further includes:

[0045] The synchronizer control module is configured to control the transmission to perform a synchronizer pre-synchronization operation to move the synchronizer fork to a target fork position when the first speed difference is less than the first speed threshold.

[0046] In a third aspect, based on the same inventive concept, an embodiment of the present application provides a mode switching system, the system comprising a vehicle controller, a transmission controller, a motor controller and an engine controller; wherein,

[0047] The vehicle controller is configured to determine a target motor speed and a target motor torque of the first motor in response to a mode switching request from the series mode to the direct drive mode, and to send a clutch state maintaining request to the transmission controller and an engine state maintaining request to the engine controller;

[0048] The transmission controller is configured to maintain the clutch in a closed state in response to the clutch state maintaining request;

[0049] The engine controller is used to keep the engine in a driving state in response to the engine state keeping request; wherein the first motor is connected to the engine through the clutch;

[0050] The vehicle controller is further configured to send a motor control request including the target motor speed and the target motor torque to the motor controller;

[0051] The motor controller is configured to adjust the first motor based on the target motor speed and the target motor torque in response to the motor control request, so that the gearbox meets a preset shift condition;

[0052] The vehicle controller is further configured to send a gear shift request to the gearbox controller when the gearbox meets the gear shift condition;

[0053] The transmission controller is further configured to control the transmission to switch to a target gear corresponding to the direct drive mode in response to the gear switching request, so that the vehicle switches from the series mode to the direct drive mode.

[0054] In a fourth aspect, based on the same application concept, an embodiment of the present application provides a vehicle, including the mode switching system proposed in the third aspect of the present application.

[0055] A mode switching method provided in an embodiment of the present application can determine the target motor speed and target motor torque of the first motor in response to a mode switching request to switch from series mode to direct drive mode, keep the clutch in a closed state and the engine in a driving state, and adjust the first motor based on the target motor speed and target motor torque so that the transmission meets the preset shifting conditions; and then, when the transmission meets the shifting conditions, control the transmission to switch to the target gear corresponding to the direct drive mode, so that the vehicle switches from series mode to direct drive mode. By adjusting the speed and torque of the first motor, the embodiment of the present application can complete the transmission shifting operation without opening the clutch and without interrupting the engine torque during the mode switching process, and then after the transmission switches to the target gear, the engine can immediately output torque through the transmission. In this way, the vehicle can switch from series mode to direct drive mode more quickly and smoothly, thereby effectively improving the dynamic response performance of the entire vehicle.

[0056] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0058] FIG1 is a schematic structural diagram of a hybrid vehicle in one embodiment of the present application.

[0059] FIG2 is a flowchart of the steps of a mode switching method in an embodiment of the present application.

[0060] FIG3 is a schematic diagram of functional modules of a mode switching device in an embodiment of the present application.

[0061] FIG4 is a schematic structural diagram of a mode switching system in an embodiment of the present application.

[0062] FIG5 is a schematic structural diagram of a vehicle in an embodiment of the present application. Specific embodiments

[0063] The technical solutions 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.

[0064] 1 , which shows a schematic structural diagram of a hybrid vehicle in an embodiment of the present application, including a first motor 101, a second motor 102, an engine 103, a clutch 104, a synchronizer 105, and a differential 106. The first motor 101 is disposed on a front axle and connected to one end of an input shaft of a gearbox. The other end of the input shaft is connected to the engine 103 via a clutch 104. The input shaft is connected to an output shaft of the gearbox via a gear set. The output shaft is connected to a transmission gear meshing with the differential 106. The synchronizer 105 is connected to the gear set for synchronizing the gear speeds between different gears. The second motor 102 is disposed on a rear axle for providing power to the rear wheels via a rear-drive propeller shaft to drive the vehicle.

[0065] A hybrid vehicle employing the above-described architecture is equipped with a first motor 101, a second motor 102, and an engine 103. Therefore, to accommodate different road conditions and driving requirements, multiple driving modes are typically provided, including a series mode and a direct drive mode. In series mode, the engine 103 is running, the clutch 104 is engaged, and the synchronizer 105 is in neutral. The first motor 101 generates electricity, while the second motor 102 drives the vehicle. In this way, the engine 103 drives the first motor 101 to generate electricity, and the generated electricity is supplied to the second motor 102, which then drives the vehicle. In direct drive mode, the clutch 104 is engaged, the synchronizer 105 is engaged, and the engine 103 and the first motor 101 jointly drive the front axle, while the second motor 102 drives the rear axle.

[0066] In related technologies, when a hybrid vehicle accelerates by deeply pressing the accelerator, it is necessary to switch the vehicle from series mode to direct drive mode. However, in the traditional mode switching strategy, the vehicle needs to first disconnect the clutch 104 and control the transmission to switch to the target gear corresponding to the direct drive mode, and then perform torque reduction and speed regulation operations on the engine 101 so that the speed difference at both ends of the clutch 104 meets the clutch closing conditions, and then re-close the clutch 104. After the clutch 104 is closed, the engine 101 still needs a certain amount of time to recover the torque, which makes the engine unable to respond to the driver's power needs in time.

[0067] It can be seen that in the traditional mode switching strategy, due to the need to control the opening and closing of the clutch and the engine torque reduction, not only does it lead to a longer switching link and a longer mode switching time, but it also causes engine power interruption, resulting in untimely power response and affecting the driver's driving experience.

[0068] In response to the problem of poor vehicle dynamic response performance during the switching process from series mode to direct drive mode in current hybrid vehicles, the present application aims to provide a mode switching method, device, system and vehicle. By adjusting the speed and torque of the first motor, during the mode switching process, the gear shifting operation of the transmission can be completed without opening the clutch and without interrupting the engine torque. After the transmission switches to the target gear, the engine can immediately output torque through the transmission. In this way, the vehicle can switch from series mode to direct drive mode more quickly and smoothly, thereby effectively improving the dynamic response performance of the vehicle.

[0069] 2 , a mode switching method of the present application is shown, which is applied to a hybrid vehicle using the above architecture. The method may include the following steps:

[0070] S201 : In response to a mode switching request from the series mode to the direct drive mode, determining a target motor speed and a target motor torque of the first motor, and keeping the clutch in a closed state and the engine in a driving state.

[0071] It should be noted that the execution entity of this embodiment can be a computing service device with data processing, network communication, and program execution functions, or an electronic device with the above functions, such as a driving computer, an onboard computer, etc., such as an ECU (Electronic Control Unit), a BCM (Body Control Module), or a VCU (Vehicle Control Unit). This embodiment will be described using the VCU as the execution entity. It should be noted that this implementation does not impose specific restrictions on the execution entity of the vehicle.

[0072] In this embodiment, the VCU can monitor the accelerator pedal signal to determine whether the driver has triggered a mode switch request. In a specific implementation, the accelerator pedal signal may include accelerator pedal opening and accelerator pedal rate of change. Thus, if the VCU detects that the vehicle's current driving mode is series mode, the accelerator pedal opening is greater than an opening threshold, and the accelerator pedal rate of change is greater than a rate of change threshold, it determines that the driver has triggered a mode switch request from series mode to direct drive mode. In response to this mode switch request, the VCU determines the target motor speed and target motor torque for the first motor, while simultaneously maintaining the clutch in a closed state and the engine in a driving state.

[0073] In a specific implementation, the VCU will respond to the mode switching request and send a clutch state holding request to the transmission controller, so that the transmission controller responds to the clutch state holding request and keeps the clutch in a closed state; at the same time, it will send an engine state holding request to the engine controller, so that the engine controller responds to the engine state holding request and keeps the engine in a driving state.

[0074] In this embodiment, the VCU may also send a gear signal including a target gear corresponding to the direct drive mode to the transmission controller, so that the transmission controller obtains the target gear and switches to the target gear when the transmission meets the shifting conditions.

[0075] It should be noted that, since the first motor is connected to the input shaft, the current motor speed of the first motor is the current input shaft speed of the input shaft, that is, the target motor speed represents the speed at which the gearbox can be engaged in the target gear; and when the clutch is closed, the first motor is rigidly connected to the engine. At this time, the torque of the first motor and the engine will be applied to the input shaft at the same time. If the torques output by the first motor and the engine are the same in magnitude but opposite in direction, the torque superimposed on the input shaft is zero, that is, the target motor torque is the torque used to balance the current output torque of the engine.

[0076] S202: Based on the target motor speed and the target motor torque, adjust the first motor so that the transmission meets a preset shift condition.

[0077] In this embodiment, since the first motor is connected to the engine via the input shaft and clutch, adjusting the speed of the first motor allows for adjustment of the input shaft's speed. Simultaneously, adjusting the torque of the first motor effectively balances the torques applied to the input shaft by the engine and the first motor, thereby adjusting the torque of the input shaft. Thus, adjusting the first motor allows the transmission to meet preset shift conditions without disengaging the clutch or reducing engine torque.

[0078] In a specific implementation, the VCU can send a motor control request including a target motor speed and a target motor torque to the motor controller, so that the motor controller responds to the motor control request and adjusts the first motor based on the target motor speed and the target motor torque so that the gearbox meets the preset shifting conditions.

[0079] In this embodiment, while the motor controller is adjusting the speed and torque of the first motor, the VCU will obtain the motor operating status of the first motor returned by the motor controller in real time, and then determine whether the gearbox meets the preset shifting conditions based on the motor operating status.

[0080] In a specific implementation, the motor operating status may include the current motor speed and the current motor torque. Thus, the VCU can determine whether the first motor has completed speed regulation based on the current motor speed, and whether the first motor has completed torque regulation based on the current motor torque. Furthermore, if it is detected that the first motor has completed both speed regulation and torque regulation, the VCU determines that the gearbox meets the shifting conditions.

[0081] S203: When the transmission satisfies the shifting conditions, the transmission is controlled to switch to the target gear corresponding to the direct drive mode, so that the vehicle switches from the series mode to the direct drive mode.

[0082] In this embodiment, after the VCU detects that the transmission meets the gear shifting conditions, it will send a gear switching request to the transmission controller; so that the transmission controller responds to the gear switching request and controls the transmission to switch to the target gear corresponding to the direct drive mode, so that the vehicle switches from series mode to direct drive mode.

[0083] It should be noted that in direct-drive mode, the VCU controls the engine, first motor, and second motor to jointly drive the vehicle according to a preset torque distribution strategy. Specifically, the torque distribution strategy includes a front-axle torque distribution strategy and a rear-axle torque output strategy. The VCU executes the front-axle torque distribution strategy, allocating different output torques to the engine and first motor to jointly drive the vehicle's front axle. Simultaneously, the VCU executes the rear-axle torque output strategy, controlling the second motor's output torque to drive the vehicle's rear axle.

[0084] The embodiment of the present application adjusts the speed and torque of the first motor so that during the mode switching process, the engine can remain in the driving state and the clutch can remain in the closed state. After the transmission completes the gear shift, the engine can immediately output torque to cooperate with the first motor to jointly drive the front axle. Since the process of opening and closing the clutch and reducing and increasing the torque of the engine is reduced, the vehicle can switch from the series mode to the direct drive mode more quickly and smoothly, while avoiding the user's sense of power interruption, achieving better acceleration performance and faster power response, thereby effectively improving the power response performance of the entire vehicle and the user's driving experience.

[0085] In one feasible implementation, the step of determining the target motor speed and target motor torque of the first motor in S201 may specifically include the following sub-steps:

[0086] S201 - 1 : Determine a target motor speed of the first motor based on the current wheel speed of the target wheel and the speed ratio between the target wheel and the input shaft of the transmission.

[0087] It should be noted that the target wheel refers to the wheel located on the same side as the first motor. For example, when the first motor, the engine and the gearbox are arranged on the front axle of the vehicle, the target wheel refers to the front axle wheel.

[0088] In a specific implementation, the current wheel speed can be determined based on the speed signal collected by the wheel speed sensor; it can also be determined based on the current vehicle speed. For example, the current wheel speed of the target wheel can be determined based on the ratio of the current vehicle speed to the wheel circumference.

[0089] In this embodiment, the target motor speed is calculated based on the current wheel speed and the speed ratio between the target wheel and the transmission input shaft. Specifically, the speed ratio between the target wheel and the transmission input shaft can be calculated based on a first speed ratio between the target wheel and the transmission output shaft and a second speed ratio corresponding to the target gear.

[0090] In a specific implementation, the target motor speed can be determined according to the following formula: n = n0 × i1 × i2;

[0091] Among them, n represents the target motor speed of the first motor, n0 represents the current wheel speed of the target wheel, i1 represents the first speed ratio between the target wheel and the gearbox output shaft, and i2 represents the second speed ratio corresponding to the target gear.

[0092] It should be noted that the second speed ratio corresponding to the target gear represents the speed ratio between the gearbox output shaft and the gearbox input shaft when the gearbox is switched to the target gear.

[0093] In this embodiment, by controlling the target motor speed output by the first motor, the speed synchronization between the transmission input shaft and the transmission output shaft can be achieved under the speed adjustment of the first motor, thereby enabling the transmission to smoothly complete the gear shifting operation.

[0094] S201 - 2 : Determine the opposite of the current output torque of the engine as the target motor torque of the first motor.

[0095] In this embodiment, to ensure that the negative torque output by the first motor can effectively offset the positive torque output by the engine, the VCU, after obtaining the current output torque from the engine control feedback, determines the inverse of the current output torque as the target motor torque. In this way, the torque jointly applied to the transmission input shaft by the engine and the first motor can be balanced to 0 N·m.

[0096] In this embodiment, by controlling the first motor to output the target motor torque, the torque of the transmission input shaft can be effectively balanced under the torque adjustment of the first motor, thereby avoiding the transmission input shaft speed change due to the existence of torque, thereby avoiding transmission shift failure or affecting the shift quality.

[0097] In a feasible implementation, S202 may specifically include the following sub-steps:

[0098] S202 - 1 : Based on the target motor speed, adjust the current motor speed of the first motor.

[0099] In this embodiment, after the VCU sends the target motor speed to the motor controller, it will exit the PI (proportional-integral) speed loop in series mode and control the motor controller to activate the speed regulation PI speed loop, so that the motor controller controls the current motor speed of the first motor to follow the target motor speed through closed-loop control.

[0100] In a specific implementation, a preset PI adjustment strategy can be used to achieve closed-loop control of the motor speed. Specifically, the motor controller has a built-in proportional controller and an integral controller. The motor controller will first calculate the first speed difference between the target motor speed and the current motor speed, and then input the current motor speed and the first speed difference into the proportional controller, which can output a proportional adjustment value; the current motor speed and the first speed difference are input into the integral controller, which can output an integral adjustment value; and then, based on the proportional adjustment value and the integral adjustment value, the speed of the first motor is adjusted.

[0101] In this embodiment, by performing closed-loop control on the motor speed, rapid and accurate control of the current motor speed can be achieved.

[0102] In this embodiment, as the speed regulation proceeds, the current motor speed will continue to approach the target motor speed, and the first speed difference will continue to decrease. If the motor controller detects that the first speed difference is less than a first speed threshold, it determines that the current motor speed meets the torque regulation condition. The first speed threshold can be set to 100 rpm.

[0103] In this embodiment, the motor controller also feeds back the first speed difference to the VCU in real time, so that the VCU can monitor the speed adjustment status of the first motor in real time.

[0104] S202-2: When the current motor speed meets the torque adjustment condition, torque adjustment is performed on the current motor torque of the first motor based on the target motor torque, so that the transmission meets the preset shifting condition.

[0105] In this embodiment, after the first motor completes speed regulation, the motor controller will be controlled to exit the speed regulation PI speed loop and activate the torque control mode of the motor controller so that the motor controller adjusts the current motor torque of the first motor to the target motor torque.

[0106] In a specific implementation, the current motor torque of the first motor may be gradually increased according to a preset torque adjustment gradient until the gearbox meets a preset shift condition. The torque adjustment gradient represents the amount of change in the current motor torque of the first motor per unit time.

[0107] In this embodiment, the VCU will obtain the current motor torque fed back by the motor controller in real time, and calculate the absolute value of the sum of the current motor torque and the current output torque of the engine. At the same time, when the VCU detects that the first speed difference is less than the second speed threshold, it will trigger the timing of the duration of the first speed difference being less than the second speed threshold. Furthermore, when it is detected that the absolute value is less than the torque threshold, the first speed difference is less than the second speed threshold, and the duration is greater than the duration threshold, it is determined that the gearbox meets the shifting conditions.

[0108] It should be noted that after the motor controller exits the PI speed control loop, the current motor speed of the first motor can continue to narrow the gap with the target motor speed due to inertia. Therefore, the second speed threshold can be set lower than the first speed threshold, for example, 50 rpm; and the duration threshold can be set to 50 ms. This can shorten the speed adjustment time of the first motor while ensuring that the gearbox meets the shifting conditions, thereby improving shifting efficiency.

[0109] In this embodiment, by detecting the absolute value, it is possible to ensure that the torque of the transmission input shaft is maintained within a relatively small torque threshold; at the same time, by continuously monitoring the duration, it is possible to ensure that the speed of the transmission input shaft can be stably maintained within the allowable fluctuation range, and then, from both the torque and speed aspects, it is ensured that the transmission can smoothly complete the gear shift without opening the clutch and without interrupting the engine torque.

[0110] In one feasible implementation, the step of adjusting the current motor torque of the first motor based on the target motor torque in S202-2 may specifically include the following sub-steps:

[0111] S202-2-1: Based on the fluctuation amplitude of the current output torque of the engine, the target motor torque is corrected in real time to obtain a corrected target motor torque.

[0112] In this embodiment, unlike electric motors, which can achieve rapid and precise torque control, the engine's torque magnitude and torque response time are affected by numerous factors, such as fuel injection quantity and injection rate, making precise engine torque control difficult and susceptible to torque fluctuation. Therefore, to prevent engine torque fluctuations from causing inaccurate target motor torque for the first motor, the VCU obtains the current engine output torque from the engine controller in real time during torque regulation. If the fluctuation amplitude of the current engine output torque exceeds a fluctuation threshold, the VCU makes a real-time correction to the target motor torque and resends the corrected target motor torque to the motor controller.

[0113] It should be noted that the fluctuation threshold represents the maximum torque that the current output torque of the engine is allowed to fluctuate. For example, when the fluctuation threshold is set to 2N·m, it means that the current output torque is allowed to fluctuate within the range of [-2, 2]. That is, when it is detected that the torque increase or torque decrease of the current output torque is greater than 2N·m, the correction of the target motor torque will be triggered.

[0114] S202-2-2: Based on the corrected target motor torque, perform torque adjustment on the current motor torque of the first motor.

[0115] In this embodiment, after receiving the corrected target motor torque, the motor controller will further adjust the current motor torque of the first motor based on the corrected target motor torque to ensure that the current motor torque of the first motor can follow the current output torque of the engine in real time.

[0116] In a feasible implementation, the mode switching method may further include the following steps:

[0117] S204: When the first speed difference is less than a first speed threshold, control the transmission to perform a synchronizer pre-synchronization operation to move the synchronizer fork to a target fork position.

[0118] It's important to note that the shift fork is a key component in the transmission's shift mechanism, used to move the synchronizer ring gear, changing the synchronizer's input / output speed ratio to shift gears. When the synchronizer is in neutral, the shift fork is in its home position, its starting point. Gear shifts from first to second, or vice versa, can be achieved by moving it left or right.

[0119] In this embodiment, the target fork position represents a position between the fork starting position and the fork terminal position corresponding to the target gear position. Optionally, the target fork position may be set at a position close to the fork terminal position.

[0120] In a specific implementation, when the VCU monitors the first speed difference, if it detects that the first speed difference is less than the first speed threshold, it sends a synchronizer pre-synchronization request to the transmission controller, so that the transmission controller responds to the synchronizer pre-synchronization request and controls the synchronizer fork to move to the target fork position.

[0121] In this embodiment, by moving the synchronizer's shift fork to the target fork position in advance, when the gear shifting conditions are met, the gearbox controller can respond to the gear shifting request sent by the VCU and quickly shift the synchronizer into the target gear. By increasing the gear shifting speed of the gearbox, the mode switching time from series mode to direct drive mode is further shortened, so that the engine and the first motor can output power through the gearbox faster.

[0122] In a second aspect, based on the same inventive concept, referring to FIG. 3 , an embodiment of the present application provides a mode switching device 300 , which includes:

[0123] a parameter determination module 301 for determining a target motor speed and a target motor torque for the first motor in response to a mode switch request from the series mode to the direct drive mode, and maintaining the clutch in a closed state and the engine in a driving state; wherein the first motor is connected to the engine via the clutch;

[0124] a motor adjustment module 302 for adjusting the first motor based on a target motor speed and a target motor torque so that the transmission satisfies a preset shift condition;

[0125] The mode switching module 303 is used to control the transmission to switch to the target gear corresponding to the direct drive mode when the transmission meets the shifting conditions, so as to switch the vehicle from the series mode to the direct drive mode.

[0126] In one embodiment of the present application, the parameter determination module 301 includes:

[0127] a motor speed determination submodule, configured to determine a target motor speed of the first motor based on a current wheel speed of the target wheel and a speed ratio between the target wheel and the gearbox input shaft;

[0128] The motor torque determination submodule is configured to determine the inverse of the current output torque of the engine as the target motor torque of the first motor.

[0129] In one embodiment of the present application, the motor adjustment module 302 includes:

[0130] a speed regulating submodule, configured to regulate the current motor speed of the first motor based on the target motor speed;

[0131] The torque adjustment submodule is used to adjust the current motor torque of the first motor based on the target motor torque when the current motor speed meets the preset torque adjustment condition, so that the transmission meets the preset shifting condition.

[0132] In one embodiment of the present application, the torque adjustment submodule includes:

[0133] a torque correction unit, configured to correct the target motor torque in real time based on the fluctuation amplitude of the current output torque of the engine to obtain a corrected target motor torque;

[0134] The torque adjustment unit is configured to adjust the current motor torque of the first motor based on the corrected target motor torque.

[0135] In one embodiment of the present application, the mode switching device 300 further includes:

[0136] The torque adjustment condition determination module is used to determine whether the current motor speed meets the torque adjustment condition when a first speed difference between the target motor speed and the current motor speed is less than a first speed threshold.

[0137] In one embodiment of the present application, the mode switching device 300 further includes:

[0138] The gear shift condition determination module is used to determine that the gearbox meets the gear shift condition when the absolute value of the sum of the current motor torque and the current output torque of the engine is less than the torque threshold, the first speed difference between the target motor speed and the current motor speed is less than the second speed threshold, and the duration of the first speed difference being less than the second speed threshold is greater than the duration threshold.

[0139] In one embodiment of the present application, the mode switching device 300 further includes:

[0140] The synchronizer control module is used to control the transmission to perform a synchronizer pre-synchronization operation when the first speed difference is less than a first speed threshold, so as to move the synchronizer shift fork to a target fork position.

[0141] It should be noted that the specific implementation of the mode switching device 300 in the embodiment of the present application refers to the specific implementation of the mode switching method proposed in the first aspect of the embodiment of the present application, and will not be repeated here.

[0142] In the third aspect, based on the same inventive concept, referring to FIG4 , the embodiment of the present application provides a mode switching system 400 , including a vehicle controller 401 , a transmission controller 402 , a motor controller 403 and an engine controller 404 ; wherein,

[0143] The vehicle controller 401 is configured to, in response to a mode switch request from the series mode to the direct drive mode, determine a target motor speed and a target motor torque for the first motor, and send a clutch state maintaining request to the transmission controller 402 and an engine state maintaining request to the engine controller 404;

[0144] The transmission controller 402 is configured to keep the clutch in a closed state in response to the clutch state keeping request;

[0145] The engine controller 404 is used to keep the engine in a driving state in response to the engine state maintenance request; wherein the first motor is connected to the engine through a clutch;

[0146] The vehicle controller 401 is further configured to send a motor control request including a target motor speed and a target motor torque to the motor controller 403 ;

[0147] The motor controller 403 is configured to adjust the first motor based on the target motor speed and the target motor torque in response to the motor control request so that the gearbox meets a preset shift condition;

[0148] The vehicle controller 401 is further configured to send a gear shift request to the gearbox controller 402 when the gearbox meets the gear shift conditions;

[0149] The transmission controller 402 is further configured to control the transmission to switch to a target gear corresponding to the direct drive mode in response to a gear switching request, so as to switch the vehicle from the series mode to the direct drive mode.

[0150] It should be noted that the specific implementation of the mode switching system 400 in the embodiment of the present application refers to the specific implementation of the mode switching method proposed in the first aspect of the present application, and will not be repeated here.

[0151] In a fourth aspect, based on the same inventive concept, referring to FIG. 5 , an embodiment of the present application provides a vehicle 500 , including the mode switching system 400 proposed in the third aspect of the present application.

[0152] It should be noted that the specific implementation of the vehicle 500 in the embodiment of the present application refers to the specific implementation of the mode switching system 400 proposed in the third aspect of the embodiment of the present application, and will not be repeated here.

[0153] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, devices, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0154] The present application embodiment is described with reference to the flow chart and / or block diagram of the method, terminal device (system), and computer program product according to the embodiment of the present application. It should be understood that each process and / or box in the flow chart and / or block diagram and the combination of the process and / or box in the flow chart and / or block diagram can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing terminal device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing terminal device produce a device for realizing the function specified in one process or multiple processes and / or one box or multiple boxes of the flow chart.

[0155] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing terminal device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including an instruction device that implements the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0156] These computer program instructions can also be loaded onto a computer or other programmable data processing terminal device so that a series of operating steps are executed on the computer or other programmable terminal device to produce computer-implemented processing, so that the instructions executed on the computer or other programmable terminal device provide steps for implementing the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0157] Although preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they become aware of the basic inventive concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the embodiments of the present invention.

[0158] Finally, it should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or terminal device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or terminal device that includes the element.

[0159] The above is a detailed introduction to the mode switching method, device, system and vehicle provided by the present application. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea; at the same time, for general technical personnel in this field, based on the ideas of the present application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A mode switching method, wherein: The method comprises: In response to a mode switching request from the series mode to the direct drive mode, a target motor speed and a target motor torque of the first motor are determined, and the clutch is kept in a closed state and the engine is in a driving state; wherein the first motor is connected to the engine through the clutch; Based on the target motor speed and the target motor torque, adjusting the first motor so that the gearbox meets a preset shift condition; When the gearbox meets the gear shifting condition, the gearbox is controlled to switch to the target gear corresponding to the direct drive mode, so that the vehicle switches from the series mode to the direct drive mode.

2. The mode switching method according to claim 1, wherein: The step of determining a target motor speed and a target motor torque of the first motor comprises: Determining a target motor speed of the first motor based on a current wheel speed of a target wheel and a gear ratio between the target wheel and a gearbox input shaft; The inverse of the current output torque of the engine is determined as the target motor torque of the first motor.

3. The mode switching method according to claim 2, wherein: The step of adjusting the first motor based on the target motor speed and the target motor torque so that the gearbox meets a preset shifting condition includes: Based on the target motor speed, adjusting the current motor speed of the first motor; When the current motor speed satisfies a preset torque adjustment condition, torque adjustment is performed on the current motor torque of the first motor based on the target motor torque so that the gearbox satisfies a preset shifting condition.

4. The mode switching method according to claim 3, wherein: The step of performing torque adjustment on the current motor torque of the first motor based on the target motor torque comprises: Based on the fluctuation amplitude of the current output torque of the engine, the target motor torque is corrected in real time to obtain a corrected target motor torque; Based on the corrected target motor torque, torque adjustment is performed on the current motor torque of the first motor.

5. The mode switching method according to claim 3, wherein: After the step of adjusting the current motor speed of the first motor based on the target motor speed, the method further includes: In a case where a first speed difference between the target motor speed and the current motor speed is less than a first speed threshold, it is determined that the current motor speed satisfies the torque adjustment condition.

6. The mode switching method according to claim 3, wherein: After the step of adjusting the current motor torque of the first motor based on the target motor torque, the method further includes: When the absolute value of the sum of the current motor torque and the current output torque of the engine is less than a torque threshold, the first speed difference between the target motor speed and the current motor speed is less than a second speed threshold, and the duration of the first speed difference being less than the second speed threshold is greater than a duration threshold, it is determined that the gearbox meets the shifting condition.

7. The mode switching method according to claim 5, wherein: The method further comprises: When the first speed difference is less than the first speed threshold, the transmission is controlled to perform a synchronizer pre-synchronization operation to move the shift fork of the synchronizer to a target shift fork position.

8. The mode switching method according to claim 1, wherein: The method further comprises: The mode switching request is obtained by monitoring the accelerator pedal signal.

9. The mode switching method according to claim 2, wherein: The method further includes: determining the target motor speed according to the formula n=n0×i1×i2: Among them, n represents the target motor speed of the first motor, n0 represents the current wheel speed of the target wheel, i1 represents the first speed ratio between the target wheel and the gearbox output shaft, and i2 represents the second speed ratio corresponding to the target gear.

10. The mode switching method according to claim 5, wherein: The first rotation speed threshold is set to 100 rpm.

11. The mode switching method according to claim 6, wherein: The second rotation speed threshold is 50 rpm.

12. The mode switching method according to claim 6, wherein: The duration threshold is set to 50 ms.

13. The mode switching method according to claim 4, wherein: The target motor torque is corrected in real time based on the fluctuation amplitude of the current output torque of the engine to obtain the corrected target motor torque, including: If it is detected that the fluctuation amplitude of the current output torque of the engine exceeds the fluctuation threshold, the target motor torque is corrected in real time to obtain a corrected target motor torque.

14. The mode switching method according to claim 13, wherein: The fluctuation threshold is set to 2 N·m.

15. The mode switching method according to claim 3, wherein: When the current motor speed satisfies the preset torque adjustment condition, the current motor torque of the first motor is torque adjusted based on the target motor torque so that the gearbox satisfies the preset shifting condition, including: According to a preset torque adjustment gradient, the current motor torque of the first motor is gradually increased until the gearbox meets a preset shifting condition, wherein the torque adjustment gradient represents a change in the current motor torque of the first motor per unit time.

16. The mode switching method according to claim 7, wherein: The target shift fork position represents a position between a shift fork starting position and a shift fork terminal position corresponding to a target gear position.

17. The mode switching method according to claim 7, wherein: The target shift fork position is a position close to the shift fork terminal position.

18. The mode switching method according to claim 7, wherein: When the first speed difference is less than the first speed threshold, controlling the gearbox to perform a synchronizer pre-synchronization operation to move the synchronizer fork to a target fork position includes: When the first speed difference is less than the first speed threshold, a synchronizer pre-synchronization request is sent to a transmission controller through the vehicle controller, so that the transmission controller responds to the synchronizer pre-synchronization request and controls the synchronizer fork to move to a target fork position.

19. A mode switching system, wherein: The system includes a vehicle controller, a gearbox controller, a motor controller and an engine controller; wherein, The vehicle controller is used to determine the target motor speed and target motor torque of the first motor in response to a mode switching request from the series mode to the direct drive mode, and send a clutch state holding request to the transmission controller and an engine state holding request to the engine controller; The transmission controller is used for keeping the clutch in a closed state in response to the clutch state keeping request; The engine controller is used to keep the engine in a driving state in response to the engine state keeping request; wherein the first motor is connected to the engine through the clutch; The vehicle controller is further used to send a motor control request including the target motor speed and the target motor torque to the motor controller; The motor controller is used for adjusting the first motor in response to the motor control request based on the target motor speed and the target motor torque so that the gearbox meets a preset shift condition; The vehicle controller is further configured to send a gear shift request to the gearbox controller when the gearbox meets the gear shift condition; The transmission controller is further configured to control the transmission to switch to a target gear corresponding to the direct drive mode in response to the gear switching request, so that the vehicle switches from the series mode to the direct drive mode.

20. A vehicle, wherein: Comprising the mode switching system as claimed in claim 19.

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