Vehicle mode switching method, device and system and vehicle

Abstract

The invention provides a vehicle mode switching method, device and system and a vehicle, and belongs to the technical field of vehicle control. According to the embodiment of the invention, in response to a mode switching request, a clutch is kept in a closed state, an engine is kept in a driving state, torque adjustment is conducted on a first motor, and when a first synchronizer meets a first gear switching condition, the first synchronizer is switched to a second gear; according to the invention, the combined gear can be switched to the power split gear, and the rotating speed of the first motor is adjusted, so that when the second synchronizer meets the second gear switching condition, the neutral gear can be switched to the target gear. According to the embodiment of the invention, the gear shifting operation of the first synchronizer and the second synchronizer can be sequentially completed on the premise of not opening a clutch and not interrupting the torque of the engine, so that the engine can immediately output torque to the wheel end through the power dividing mechanism while continuously driving the first motor to be kept in a power generation state, and the power generation efficiency is improved. And the dynamic response performance of the vehicle in the mode switching process is effectively improved.

Description

Technical Field

[0001] This application relates to the technical field of vehicle control, and particularly to a vehicle mode switching method, device, system, and vehicle. Background Art

[0002] With the rapid development of the automotive industry and in response to the national policies on energy conservation, emission reduction, and carbon balance, traditional fuel vehicles are gradually moving towards hybrid vehicles. To adapt to different road conditions and driving requirements, hybrid vehicles usually have multiple driving modes including a series mode and a power split mode. During vehicle driving, according to changes in road conditions and driving requirements, the driving modes will switch to each other under certain conditions.

[0003] In the related art, when a vehicle switches from the series mode to the power split mode, it usually needs to first open the clutch, then perform torque reduction and speed regulation operations on the engine, and then re-close the clutch after the torque reduction and speed regulation operations are completed to complete the mode switch. However, this method has a process of opening and closing the clutch, which will cause the engine power to be interrupted, and thus not only cause the motor to interrupt power generation, but also has problems such as a long mode switch time and untimely engine power response, thereby affecting the overall vehicle power response performance. Summary of the Invention

[0004] This application provides a vehicle mode switching method, device, system, and vehicle to solve the problem of poor overall vehicle power response performance during the process of a hybrid vehicle switching from the series mode to the power split mode.

[0005] To solve the above problems, this application adopts the following technical solutions:

[0006] In a first aspect, an embodiment of this application provides a vehicle mode switching method. The vehicle includes an engine, a clutch, a first motor, and a gearbox. The gearbox includes a power split mechanism, a gearbox input shaft, a gearbox output shaft, a first synchronizer, and a second synchronizer. The engine is connected to a first input end of the power split mechanism through the clutch, the first motor is connected to a second input end of the power split mechanism, an output end of the power split mechanism is connected to the gearbox input shaft, the second synchronizer is arranged between the gearbox input shaft and the gearbox output shaft, and the first synchronizer is arranged between the first input end and the output end. The method includes:

[0007] In response to a mode switch request for switching from the series mode to the power split mode, keep the clutch in a closed state, keep the engine in a driving state, and perform torque adjustment on the current motor torque of the first motor to make the first synchronizer meet the first gear shift condition;

[0008] When the first synchronizer meets the first gear shifting condition, control the first synchronizer to shift from the engaged gear to the power split gear; and adjust the current motor speed of the first motor to make the second synchronizer meet the second gear shifting condition;

[0009] When the second synchronizer meets the second gear shifting condition, control the second synchronizer to shift from the neutral gear to the target gear, so that the vehicle switches from the series mode to the power split mode.

[0010] In an embodiment of the present application, the power split mechanism includes a ring gear, a sun gear, a plurality of planet gears meshing between the ring gear and the sun gear, and a planet carrier rotatably connected to the plurality of planet gears; the planet carrier is connected to the engine as the first input end, the sun gear is connected to the first motor as the second input end, the ring gear is connected to the transmission input shaft as the output end, and the first synchronizer is arranged between the planet carrier and the ring gear;

[0011] The step of adjusting the current motor torque of the first motor includes:

[0012] Based on the current engine torque of the engine and the first transmission ratio between the sun gear and the planet carrier, determine the target motor torque of the first motor;

[0013] Based on the target motor torque, adjust the current motor torque of the first motor.

[0014] In an embodiment of the present application, the method further includes:

[0015] When the first torque difference between the current motor torque and the target motor torque is less than the first torque threshold, trigger the timing of the first duration for which the first torque difference is less than the first torque threshold and the timing of the second duration for which the fluctuation amplitude of the current engine torque is less than the second torque threshold;

[0016] When the first duration is greater than the first duration threshold and the second duration is greater than the second duration threshold, determine that the first synchronizer meets the first gear shifting condition.

[0017] In an embodiment of the present application, the step of adjusting the current motor speed of the first motor includes:

[0018] Based on the current gear of the first synchronizer and the target gear of the second synchronizer, determine the target motor speed of the first motor;

[0019] Adjust the current motor speed of the first motor based on the target motor speed.

[0020] In an embodiment of the present application, the step of determining the target motor speed of the first motor based on the current gear position of the first synchronizer and the target gear position of the second synchronizer includes:

[0021] When the current gear position of the first synchronizer is the power split gear position, determine the speed ratio between the planet carrier and the ring gear as the second speed ratio;

[0022] Based on the target gear position of the second synchronizer, determine the speed ratio between the transmission input shaft and the target wheel as the third speed ratio;

[0023] Based on the second speed ratio, the first speed ratio, and the third speed ratio, determine the fourth speed ratio between the target wheel and the first motor;

[0024] Based on the fourth speed ratio and the current wheel speed of the target wheel, determine the target motor speed of the first motor.

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

[0026] When the current motor speed of the first motor reaches the target motor speed, trigger the timing of the third duration during which the fluctuation amplitude of the current motor speed is less than the speed threshold;

[0027] When the third duration is greater than the third duration threshold, determine that the second synchronizer meets the second gear shift condition.

[0028] In an embodiment of the present application, when the second synchronizer meets the second gear shift condition, the step of controlling the second synchronizer to shift from the neutral gear to the target gear position includes:

[0029] When the second synchronizer meets the second gear shift condition, control the second synchronizer to perform a pre-synchronization operation so that the shift fork of the second synchronizer moves to the pre-synchronization position;

[0030] When it is determined that the shift fork of the second synchronizer reaches the pre-synchronization position and the first torque difference between the current motor torque and the target motor torque is less than the fourth torque threshold, control the second synchronizer to move from the pre-synchronization position to the target position so that the second synchronizer shifts to the target gear position.

[0031] Second aspect, based on the same inventive concept, an embodiment of the present application provides a vehicle mode switching device. The vehicle includes an engine, a clutch, a first motor, and a transmission. The transmission includes a power split mechanism, a transmission input shaft, a transmission output shaft, a first synchronizer, and a second synchronizer. The engine is connected to a first input end of the power split mechanism through the clutch. The first motor is connected to a second input end of the power split mechanism. An output end of the power split mechanism is connected to the transmission input shaft. The second synchronizer is disposed between the transmission input shaft and the transmission output shaft. The first synchronizer is disposed between the first input end and the output end. The device includes:

[0032] A torque adjustment module, configured to, in response to a mode switching request for switching from a series mode to a power split mode, keep the clutch in a closed state, keep the engine in a driving state, and perform torque adjustment on a current motor torque of the first motor, so that the first synchronizer meets a first gear shifting condition;

[0033] A speed adjustment module, configured to, when the first synchronizer meets the first gear shifting condition, control the first synchronizer to switch from an engaged gear to a power split gear; and perform speed adjustment on a current motor speed of the first motor, so that the second synchronizer meets a second gear shifting condition;

[0034] A gear shifting module, configured to, when the second synchronizer meets the second gear shifting condition, control the second synchronizer to switch from a neutral gear to a target gear, so that the vehicle switches from the series mode to the power split mode.

[0035] In an embodiment of the present application, the power split mechanism includes a ring gear, a sun gear, a plurality of planet gears meshing between the ring gear and the sun gear, and a planet carrier rotatably connected to the plurality of planet gears. The planet carrier serves as the first input end and is connected to the engine. The sun gear serves as the second input end and is connected to the first motor. The ring gear serves as the output end and is connected to the transmission input shaft. The first synchronizer is disposed between the planet carrier and the ring gear. The torque adjustment module includes:

[0036] A target motor torque determination sub-module, configured to determine a target motor torque of the first motor based on a current engine torque of the engine and a first transmission ratio between the sun gear and the planet carrier;

[0037] A torque adjustment sub-module, configured to perform torque adjustment on a current motor torque of the first motor based on the target motor torque.

[0038] In an embodiment of the present application, the vehicle mode switching device further includes:

[0039] A first timing module, configured to trigger timing of a first duration during which a first torque difference between the current motor torque and the target motor torque is less than a first torque threshold, and timing of a second duration during which a fluctuation amplitude of the current engine torque is less than a second torque threshold, when the first torque difference between the current motor torque and the target motor torque is less than the first torque threshold;

[0040] A first condition determination module, configured to determine that the first synchronizer meets the first gear shifting condition when the first duration is greater than a first duration threshold and the second duration is greater than a second duration threshold.

[0041] In an embodiment of the present application, the rotational speed adjustment module includes:

[0042] A target motor rotational speed determination sub-module, configured to determine a target motor rotational speed of the first motor based on a current gear position of the first synchronizer and a target gear position of the second synchronizer;

[0043] A rotational speed adjustment sub-module, configured to adjust the current motor rotational speed of the first motor based on the target motor rotational speed.

[0044] In an embodiment of the present application, the target motor rotational speed determination sub-module includes:

[0045] A first speed ratio determination unit, configured to determine that a speed ratio between the planet carrier and the ring gear is a second speed ratio when the current gear position of the first synchronizer is the power split gear;

[0046] A second speed ratio determination unit, configured to determine that a speed ratio between the transmission input shaft and the target wheel is a third speed ratio based on the target gear position of the second synchronizer;

[0047] A third speed ratio determination unit, configured to determine a fourth speed ratio between the target wheel and the first motor based on the second speed ratio, the first speed ratio, and the third speed ratio;

[0048] A target motor rotational speed determination unit, configured to determine the target motor rotational speed of the first motor based on the fourth speed ratio and the current wheel rotational speed of the target wheel.

[0049] In an embodiment of the present application, the vehicle mode switching device further includes:

[0050] A second timing module, configured to trigger timing of a third duration during which a fluctuation amplitude of the current motor rotational speed is less than a rotational speed threshold when the current motor rotational speed of the first motor reaches the target motor rotational speed;

[0051] A second condition determination module, configured to determine that the second synchronizer meets the second gear shifting condition when the third duration is greater than a third duration threshold.

[0052] In an embodiment of the present application, the gear shifting module includes:

[0053] A pre-synchronization sub-module, configured to control the second synchronizer to perform a pre-synchronization operation when the second synchronizer meets the second gear shifting condition, so that the shift fork of the second synchronizer moves to a pre-synchronization position;

[0054] A gear shifting sub-module, configured to control the second synchronizer to move from the pre-synchronization position to a target position when it is determined that the shift fork of the second synchronizer reaches the pre-synchronization position and a first torque difference between the current motor torque and the target motor torque is less than a fourth torque threshold, so that the second synchronizer switches to the target gear.

[0055] In a third aspect, based on the same inventive concept, an embodiment of the present application provides a vehicle mode switching system. The vehicle includes an engine, a clutch, a first motor, and a gearbox. The gearbox includes a power split mechanism, a gearbox input shaft, a gearbox output shaft, a first synchronizer, and a second synchronizer. The engine is connected to a first input end of the power split mechanism through the clutch, the first motor is connected to a second input end of the power split mechanism, an output end of the power split mechanism is connected to the gearbox input shaft, the second synchronizer is disposed between the gearbox input shaft and the gearbox output shaft, and the first synchronizer is disposed between the first input end and the output end. The system includes a vehicle controller, a gearbox controller, a motor controller, and an engine controller. Among them,

[0056] The vehicle controller is configured to, in response to a mode switching request for switching from a series mode to a power split mode, send a clutch state holding request to the gearbox controller, send an engine state holding request to the engine controller, and send a torque adjustment request to the motor controller;

[0057] The gearbox controller is configured to, in response to the clutch state holding request, keep the clutch in a closed state;

[0058] The engine controller is configured to, in response to the engine state holding request, keep the engine in a driving state;

[0059] The motor controller is configured to, in response to the torque adjustment request, adjust the current motor torque of the first motor to enable the first synchronizer to meet the first gear shifting condition;

[0060] The vehicle controller is further configured to control the transmission controller to switch the first synchronizer from the engaged gear to the power split gear and send a rotational speed adjustment request to the motor controller when the first synchronizer meets the first gear shifting condition;

[0061] The motor controller is further configured to adjust the current motor rotational speed of the first motor in response to the rotational speed adjustment request, so that the second synchronizer meets the second gear shifting condition;

[0062] The vehicle controller is further configured to control the transmission controller to switch the second synchronizer from the neutral gear to the target gear when the second synchronizer meets the second gear shifting condition, so that the vehicle switches from the series mode to the power split mode.

[0063] Fourthly, based on the same inventive concept, an embodiment of the present application provides a vehicle, including the vehicle mode switching system proposed in the third aspect of the present application.

[0064] Compared with the prior art, the present application has the following advantages:

[0065] A vehicle mode switching method provided by an embodiment of the present application can respond to a mode switching request from the series mode to the power split mode, keep the clutch in the closed state and the engine in the driving state, and adjust the current motor torque of the first motor, so that when the first synchronizer meets the first gear shifting condition, the first synchronizer can be controlled to switch from the engaged gear to the power split gear, and the current motor rotational speed of the first motor can be adjusted, so that when the second synchronizer meets the second gear shifting condition, the second synchronizer can be controlled to switch from the neutral gear to the target gear, so that the vehicle switches from the series mode to the power split mode. By sequentially adjusting the torque and rotational speed of the first motor, the embodiment of the present application enables the shifting operations of the first synchronizer and the second synchronizer to be completed in sequence without opening the clutch and without interrupting the engine torque during the vehicle mode switching process. In this way, the engine can not only continuously drive the first motor to remain in the power generation state through the power split mechanism to meet the charging requirements of the power battery, but also immediately output torque to the wheel end through the power split mechanism, so that the vehicle can switch from the series mode to the power split mode more quickly and smoothly, effectively improving the dynamic response performance of the vehicle during the mode switching process. Description of the Drawings

[0066] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0067] Figure 1 It is a schematic structural diagram of a hybrid vehicle in an embodiment of the present application.

[0068] Figure 2 It is a flowchart of the steps of a vehicle mode switching method in an embodiment of the present application.

[0069] Figure 3 It is a schematic diagram of the functional modules of a vehicle mode switching device in an embodiment of the present application.

[0070] Figure 4 It is a schematic structural diagram of a vehicle mode switching system in an embodiment of the present application.

[0071] Figure 5 It is a schematic structural diagram of a vehicle in an embodiment of the present application. Detailed implementation manners

[0072] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0073] Refer to Figure 1 , which shows a schematic structural diagram of a hybrid vehicle in an embodiment of the present application. The hybrid vehicle is provided with an engine 101, a clutch 102, a first motor 103 and a gearbox on the front axle of the vehicle; the gearbox includes a power split mechanism 104, a gearbox input shaft 107, a gearbox output shaft 108, a first synchronizer 105 and a second synchronizer 106. The engine 101 is connected to the first input end of the power split mechanism 104 through the clutch 102, the first motor 103 is connected to the second input end of the power split mechanism 104, and the output end of the power split mechanism 104 is connected to the gearbox input shaft 107.

[0074] The second synchronizer 106 is disposed between the transmission input shaft 107 and the transmission output shaft 108 and is used to couple or disconnect the transmission input shaft 107 and the transmission output shaft 108. Specifically, when the second synchronizer 106 is in gear, the second synchronizer 106 is used to couple the transmission input shaft 107 and the transmission output shaft 108; when the second synchronizer 106 is in neutral, the second synchronizer 106 is used to disconnect the transmission input shaft 107 and the transmission output shaft 108.

[0075] The first synchronizer 105 is disposed between the first input end and the output end and is used to couple or disconnect the first input end and the output end. Specifically, when the first synchronizer 105 is in the engaged gear, the first synchronizer 105 is used to couple the first input end and the output end; when the first synchronizer 105 is in the power split gear, the first synchronizer 105 is used to disconnect the first input end and the output end. It should be noted that the first synchronizer 105 is used to control the vehicle to switch between the power split mode and other modes, that is, when the first synchronizer 105 is in the power split gear, the vehicle can be in the power split mode; when the first synchronizer 105 is in the engaged gear, the vehicle can be in other modes outside the power split mode, such as the series mode, the direct drive mode or the pure electric four-wheel drive mode and other modes.

[0076] Further, the transmission output shaft 108 is also connected to the front axle wheels through the front axle differential 109 and is used to transmit power to the front axle wheels through the front axle differential 109 to drive the front axle of the vehicle; the hybrid vehicle is also provided with a second motor (not shown in the figure) on the vehicle rear axle, and the second motor is used to transmit power to the rear axle wheels through the rear axle differential (not shown in the figure) to drive the rear axle of the vehicle.

[0077] Since the hybrid vehicle adopting the above architecture is configured with the power split mechanism 104, and the power split mechanism 104 is simultaneously connected to the engine 101, the first motor 103 and the transmission input shaft 107, the vehicle can have multiple driving modes including the series mode and the power split mode. Furthermore, by changing the gear states of the first synchronizer 105 and the second synchronizer 106, the vehicle can be switched between different driving modes. Specifically:

[0078] In the power split mode, the first synchronizer 105 is in the power split gear position. At this time, the first synchronizer is in the gear disengaged state, used to disconnect the first input end and the output end. The second synchronizer 106 is in the gear engaged state, the engine 101 is in the driving state, the clutch 102 is in the closed state, the first motor 103 is in the power generation state, and the second motor is in the driving state. At this time, the driving force output by the engine 101 is transmitted to the power split mechanism 104 through the clutch 102 and the first input end. The power split mechanism 104 then transmits a part of the driving force to the first motor 103 through the second input end to drive the first motor 103 to generate electricity (at this time, the first motor 103 outputs negative torque), and the generated electric energy is provided to the power battery for charging; the power split mechanism 104 also transmits another part of the driving force to the transmission input shaft 107 through the output end, and the transmission input shaft 107 sequentially transmits this part of the driving force to the vehicle front axle through the second synchronizer 106, the transmission output shaft 108 and the front axle differential 109 to drive the vehicle to travel. Among them, the distribution ratio of the driving force can be set according to actual needs. That is to say, in the power split mode, a part of the output power of the engine 101 is used to drive the first motor 103 to charge the power battery, and another part of the output power is used to directly drive the vehicle to travel.

[0079] In the series mode, the first synchronizer 105 is in the engaged gear position. At this time, the first synchronizer 105 is used to connect the first input end and the output end. The second synchronizer 106 is in the neutral gear position, the engine 101 is in the driving state, the clutch 102 is in the closed state, the first motor 103 is in the power generation state, and the second motor is in the driving state. At this time, since the second synchronizer 106 is in the neutral gear position, the driving force output by the engine 101 will not be transmitted to the transmission input shaft 107 through the first input end, the first synchronizer 105 and the output end. The driving force output by the engine 101 will be transmitted to the power split mechanism 104 through the first input end, and then the power split mechanism 104 will transmit all of this driving force to the first motor 103 through the second input end to drive the first motor 103 to generate electricity, and the generated electric energy is provided to the second motor to drive the vehicle to travel.

[0080] In the related art, to avoid damage to actuators such as the clutch 102 and the synchronizer, when the vehicle switches from the series mode to the power split mode, it is usually necessary for the vehicle to first open the clutch 102, and then perform torque reduction and speed regulation operations on the engine 101. After the torque reduction and speed regulation operations are completed, the clutch 102 is re-closed to complete the mode switch. However, this method has a process of opening and closing the clutch 102, which will cause the power of the engine 101 to be interrupted. On the one hand, it will cause the first motor 103 to stop generating electricity, and the first motor 103 needs to wait until the clutch 102 is completely closed and the engine 101 re-outputs torque before it can charge the power battery. On the other hand, it will also cause a longer switching link and a longer mode switching time, and the engine 101 cannot output power to the wheel end in time, thereby affecting the overall vehicle power response performance.

[0081] Aiming at the problem of poor overall vehicle power response performance during the process of a hybrid vehicle switching from the series mode to the power split mode. This application aims to provide a vehicle mode switching method. By sequentially adjusting the torque and speed of the first motor 103, during the vehicle mode switching process, the shifting operations of the first synchronizer 105 and the second synchronizer 106 can be completed in sequence without opening the clutch 102 and without interrupting the torque of the engine 101. In this way, the engine 101 can not only continuously drive the first motor 103 to maintain the power generation state through the power split mechanism 104 to meet the charging requirements of the power battery, but also immediately output torque to the wheel end through the power split mechanism 104, so that the vehicle can switch from the series mode to the power split mode more quickly and smoothly, effectively improving the power response performance of the vehicle during the mode switching process.

[0082] Referring to Figure 2 , a vehicle mode switching method of this application is shown, which is applied to a hybrid vehicle adopting the above architecture. The method may include the following steps:

[0083] S201: In response to a mode switching request for switching from the series mode to the power split mode, keep the clutch 102 in the closed state, the engine 101 in the driving state, and adjust the current motor torque of the first motor 103 to make the first synchronizer 105 meet the first gear switching condition.

[0084] It should be noted that the execution entity of this embodiment can be a computing service device with data processing, network communication, and program running functions, or an electronic device with the above functions, such as a vehicle computer, in-vehicle computer, etc., such as an ECU (Electronic Control Unit), HCU (Hybrid Control Unit), etc. This embodiment will be described with the HCU as the execution entity. It should be noted that this embodiment does not make specific restrictions on the execution entity of the vehicle.

[0085] In this embodiment, the HCU can monitor the throttle pedal signal and the SOC (State of Charge, battery charge state, also known as remaining power) of the power battery to determine whether the vehicle needs to switch from the series mode to the power split mode. Among them, the throttle pedal signal can include the throttle pedal opening and the throttle pedal change rate.

[0086] In this embodiment, by monitoring the throttle pedal signal, it can be determined whether the driver has a sudden acceleration demand; by monitoring the current remaining power of the power battery, it can be determined whether the power battery has a charging demand.

[0087] In a specific implementation, the throttle pedal signal can include the throttle pedal opening and the throttle pedal change rate. Thus, if the HCU detects that the current driving mode of the vehicle is the series mode, the throttle pedal opening is greater than the opening threshold, the throttle pedal change rate is greater than the change rate threshold, and the current remaining power of the power battery is less than the power threshold, it means that the driver has a sudden acceleration demand when the power battery has low power. At this time, to simultaneously meet the driver's power demand and the charging demand of the power battery, the vehicle will automatically trigger a mode switching request to switch from the series mode to the power split mode. Furthermore, the HCU will respond to this mode switching request, keep the clutch 102 in a closed state, the engine 101 in a driving state, and adjust the current motor torque of the first motor 103 to make the first synchronizer 105 meet the first gear switching condition.

[0088] In this embodiment, the HCU will respond to the vehicle mode switching request, 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 102 in a closed state; at the same time, 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 101 in a driving state.

[0089] Further, the HCU also sends a gear position signal including the target gear position corresponding to the power split mode to the transmission controller, so that the transmission controller can obtain the target gear position and, when the second synchronizer 106 meets the second gear shift condition, switch from the current gear position to the target gear position.

[0090] It should be noted that in the series mode, the first synchronizer 105 is in the engaged gear position. At this time, the first input end and the output end of the power split mechanism 104 are in a locked state, and the output end is connected to the transmission input shaft 107, so that the speed ratio between the first input end and the transmission input shaft 107 is 1:1. When the vehicle switches from the series mode to the power split mode, the first synchronizer 105 needs to shift from the engaged gear position to the power split gear position. At this time, the speed ratio between the first input end of the power split mechanism 104 and the transmission input shaft 107 can be set to a value greater than 1 according to needs, such as 2:1. To avoid damage to the first synchronizer 105, when the first synchronizer 105 is shifting out of gear, the torque applied to the first synchronizer 105 is required to be a small value, ideally zero.

[0091] In this embodiment, considering that when the clutch 102 is closed, the torques of the engine 101 and the first motor 103 can be applied to the power split mechanism 104 at the same time. Therefore, by adjusting the current motor torque of the first motor 103, the torque applied by the first motor 103 to the power split mechanism 104 can be used to offset the torque applied by the engine 101 to the power split mechanism 104, and then the torque acting on the first synchronizer 105 by the power split mechanism 104 can be adjusted. In this way, the torque required for the crankshaft end torque to the first synchronizer 105 to close can be balanced without opening the clutch 102 and without reducing the torque of the engine 101.

[0092] In a specific implementation, the HCU will, in response to a mode switch request, send a torque adjustment request including the target motor torque to the motor controller, so that the motor controller, in response to the torque adjustment request, adjusts the current motor torque of the first motor 103 according to the target motor torque, so that the first synchronizer 105 meets the first gear shift condition.

[0093] S202: When the first synchronizer 105 meets the first gear shift condition, control the first synchronizer 105 to shift from the engaged gear position to the power split gear position; and adjust the current motor speed of the first motor 103 to make the second synchronizer 106 meet the second gear shift condition.

[0094] In this embodiment, after the HCU detects that the first synchronizer 105 meets the first gear shifting condition and the current gear is the engaged gear, it will send a first gear shifting command indicating that the target gear is the power split gear to the transmission controller, so that the transmission controller responds to the gear shifting command and controls the first synchronizer 105 to disengage to the power split gear.

[0095] In this embodiment, if the HCU detects that the first synchronizer 105 has been switched to the power split gear, it will trigger the speed regulation of the first motor 103 and send a speed regulation request including the target motor speed to the motor controller, so that the motor controller responds to the speed regulation request and regulates the current motor speed of the first motor 103 based on the target motor speed, so that the second synchronizer 106 meets the second gear shifting condition.

[0096] It should be noted that the second synchronizer 106 is arranged between the transmission input shaft 107 and the transmission output shaft 108 and is used to adjust the gear ratio between the transmission input shaft 107 and the transmission output shaft 108. When the second synchronizer 106 is engaged, it is necessary to adjust the speed difference between both ends of the second synchronizer 106 to a small value, and ideally it is zero.

[0097] In this embodiment, considering that the first motor 103 is connected to the power split mechanism 104 and the torque balance of the engine 101 has been achieved by using the first motor 103, therefore, by adjusting the speed of the first motor 103, it is also possible to adjust the speed of the transmission input shaft 107 without opening the clutch 102 and without reducing the torque of the engine 101, so that the second synchronizer 106 meets the second gear shifting condition.

[0098] S203: When the second synchronizer 106 meets the second gear shifting condition, control the second synchronizer 106 to switch from the neutral gear to the target gear, so that the vehicle switches from the series mode to the power split mode.

[0099] In this embodiment, after the HCU detects that the second synchronizer 106 meets the second gear shifting condition and the current gear is the neutral gear, it will send a second gear shifting command including the target gear to the transmission controller, so that the transmission controller responds to the second gear shifting command and controls the second synchronizer 106 to switch from the neutral gear to the target gear corresponding to the power split mode. Among them, for a transmission with three forward gears, the target gear is usually the second gear or the third gear.

[0100] In this embodiment, after the HCU determines that the second synchronizer 106 has been switched to the target gear position, it will set the current driving mode of the vehicle from the series mode to the power split mode, and then control the engine 101, the first motor 103 and the second motor to output torque according to the torque distribution strategy in the power split mode.

[0101] Specifically, the torque distribution strategy includes the front axle torque distribution strategy and the rear axle torque output strategy. Among them, the HCU is used to execute the front axle torque distribution strategy, control the engine 101 to output a first torque with a positive value, and control the first motor 103 to output a second torque with a negative value to charge the power battery while driving the front axle of the vehicle; at the same time, the HCU is also used to execute the rear axle torque output strategy, control the second motor to output a third torque with a positive value to drive the rear axle of the vehicle.

[0102] It should be noted that the absolute value of the first torque is greater than that of the second torque. In this way, the first torque transmitted from the engine 101 to the power split mechanism 104 can be divided by the power split mechanism 104 into a generator torque and a driving torque. Among them, the generator torque is equal to the absolute value of the second torque and is used to be transmitted to the first motor 103 through the power split mechanism 104 to drive the first motor 103 to generate electricity, and the generated electric energy is provided to charge the power battery; the driving torque is the difference between the first torque and the absolute value of the second torque and is used to be transmitted to the transmission input shaft 107 through the power split mechanism 104, and then the transmission input shaft 107 is sequentially transmitted to the front axle of the vehicle through the second synchronizer 106, the transmission output shaft 108 and the front axle differential 109 to drive the vehicle to travel.

[0103] A vehicle mode switching method provided by an embodiment of the present application, by sequentially adjusting the torque and speed of the first motor 103, enables the first synchronizer 105 and the second synchronizer 106 to complete the gear shifting operations in sequence without opening the clutch 102 and without interrupting the torque of the engine 101 during the vehicle mode switching process. In this way, the engine 101 can not only continuously drive the first motor 103 to remain in the power generation state through the power split mechanism 104 to meet the charging requirements of the power battery, but also immediately output torque to the wheel end through the power split mechanism 104, so that the vehicle can switch from the series mode to the power split mode more quickly and smoothly, effectively improving the dynamic response performance of the vehicle during the mode switching process.

[0104] In a feasible embodiment, continue to refer to Figure 1, specifically, the power splitting mechanism 104 may include a ring gear 1041, a sun gear 1042, a plurality of planet gears 1043 meshing between the ring gear 1041 and the sun gear 1042, and a planet carrier 1044 rotatably connected to the plurality of planet gears 1043; the planet carrier 1044 is connected to the engine 101 as the first input end of the power splitting mechanism 104, the sun gear 1042 is connected to the first motor 103 as the second input end of the power splitting mechanism 104, the ring gear 1041 is connected to the transmission input shaft 107 as the output end of the power splitting mechanism 104, and the first synchronizer 105 is disposed between the planet carrier 1044 and the ring gear 1041.

[0105] It should be noted that in the series mode, the first synchronizer 105 is in the engaged gear position. At this time, the planet carrier 1044 and the ring gear 1041 are in a locked state. Since the second synchronizer 106 is in the neutral gear position, the driving force transmitted from the engine 101 to the planet carrier 1044 through the clutch 102 will not be transmitted to the transmission output shaft 108 through the first synchronizer 105, the ring gear 1041, and the transmission input shaft 107, but will be transmitted to the first motor 103 through the plurality of planet gears 1043 and the sun gear 1042 in sequence to drive the first motor 103 to generate electricity, and the generated electric energy is provided to the second motor to drive the vehicle.

[0106] In the power splitting mode, the first synchronizer 105 is in the power splitting gear position. At this time, the planet carrier 1044 and the ring gear 1041 are in a disengaged state. The driving force output by the engine 101 will be transmitted to the planet carrier 1044 through the clutch 102, and the planet carrier 1044 will transmit a part of the driving force to the first motor 103 through the plurality of planet gears 1043 and the sun gear 1042 in sequence to drive the first motor 103 to charge the power battery; at the same time, the planet carrier 1044 will transmit another part of the driving force to the vehicle front axle through the plurality of planet gears 1043, the ring gear 1041, the transmission input shaft 107, the second synchronizer 106, the transmission output shaft 108, and the front axle differential 109 to drive the vehicle. Based on the above structure, S201 may specifically include the following sub-steps:

[0107] S201-1: Determine the target motor torque of the first motor 103 based on the current engine torque of the engine 101 and the first gear ratio between the sun gear 1042 and the planet carrier 1044.

[0108] It should be noted that since the first motor 103 is connected to the engine 101 through the sun gear 1042, the plurality of planet gears 1043, and the planet carrier 1044 in sequence, and there is a gear ratio between the planet carrier 1044 and the sun gear 1042, the torque output by the first motor 103 cannot be directly controlled to be opposite to the current engine torque of the engine 101.

[0109] In this embodiment, to effectively balance the torques jointly exerted by the engine 101 and the first motor 103 on the planet gear 1043, the HCU will determine the target motor torque of the first motor 103 based on the current engine torque of the engine 101 and the first gear ratio between the sun gear 1042 and the planet carrier 1044. Specifically, the target motor torque can be determined according to the following formula:

[0110] T2 = -T1 × i1 (1);

[0111] where, T2 represents the target motor torque of the first motor 103, T1 represents the current engine torque of the engine 101, and i1 represents the first gear ratio between the sun gear 1042 and the planet carrier 1044.

[0112] S201-2: Based on the target motor torque, perform torque adjustment on the current motor torque of the first motor 103.

[0113] In this embodiment, after determining the target motor torque, the HCU will activate the torque control mode of the motor controller so that the motor controller adjusts the current motor torque of the first motor 103 to the target motor torque.

[0114] In a specific implementation, the current motor torque of the first motor 103 can be controlled to gradually increase or decrease to the target motor torque according to a preset torque adjustment gradient. Wherein, the torque adjustment gradient represents the change amount of the current motor torque of the first motor 103 per unit time. For example, it can be set to 100 N·m / s.

[0115] In this embodiment, by gradually increasing or decreasing the current motor torque of the first motor 103 according to the torque adjustment gradient, while realizing the adjustment of the motor torque, it can effectively avoid excessive torque change from affecting the driving smoothness of the vehicle.

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

[0117] S301: When the first torque difference between the current motor torque and the target motor torque is less than the first torque threshold, trigger the timing of the first duration for which the first torque difference is less than the first torque threshold and the timing of the second duration for which the fluctuation range of the current engine torque is less than the second torque threshold.

[0118] In this embodiment, considering that torque fluctuations may occur in both the first motor 103 and the engine 101 during the torque adjustment process, in order to ensure the smooth shifting operation of the first synchronizer 105, the torque fluctuation conditions of the first motor 103 and the engine 101 will be detected to determine whether the first motor 103 and the engine 101 are both in a stable operating state.

[0119] In a specific implementation, when the HCU first detects that the first torque difference between the current motor torque and the target motor torque is less than the first torque threshold, the timing of the first duration and the second duration will be triggered simultaneously. Among them, the first duration represents the duration of the continuous stable operation of the first motor 103 in the torque dimension; the second duration represents the duration of the continuous stable operation of the engine 101 in the torque dimension.

[0120] It should be noted that considering that the control accuracy of the first motor 103 is greater than that of the engine 101, the second torque threshold can be set greater than the first torque threshold. For example, the first torque threshold can be set to 3 N·m, and the second torque threshold can be set to 5 N·m.

[0121] S302: When the first duration is greater than the first duration threshold and the second duration is greater than the second duration threshold, it is determined that the first synchronizer 105 meets the first gear shifting condition.

[0122] In this embodiment, when the first duration is greater than the first duration threshold, it indicates that the current motor torque of the first motor 103 fluctuates near the target motor torque with a fluctuation amplitude less than the first torque threshold, that is, it is in a stable operating state; when the second duration is greater than the second duration threshold, it indicates that the current engine torque of the engine 101 fluctuates near the original engine 101 torque with a fluctuation amplitude less than the second torque threshold, and it is also in a stable operating state. Among them, the first duration threshold and the second duration threshold can be specifically set according to the control accuracy of the first motor 103 and the engine 101. For example, they can both be set to 50 ms. It should be noted that the original engine 101 torque represents the current engine torque of the engine 101 used when calculating the target motor torque of the first motor 103.

[0123] In this embodiment, by monitoring the current motor torque and the current engine torque simultaneously during the torque adjustment of the first motor 103, it is possible to accurately determine whether the first synchronizer 105 meets the first gear shifting condition, thereby ensuring that the first synchronizer 105 can shift gears smoothly and effectively avoiding situations such as damage to the first synchronizer 105 and shifting failure.

[0124] In a feasible embodiment, S202 may specifically include the following sub-steps:

[0125] S202-1: Determine the target motor speed of the first motor 103 based on the current gear position of the first synchronizer 105 and the target gear position of the second synchronizer 106.

[0126] In this embodiment, since there are a first synchronizer 105 and a second synchronizer 106 provided between the first motor 103 and the transmission input shaft 107, and different gear states of the first synchronizer 105 and the second synchronizer 106 correspond to different gear ratios, therefore, to accurately calculate the target motor speed of the first motor 103 and ensure that the second synchronizer 106 can smoothly engage the target gear position, the HCU will determine the target motor speed of the first motor 103 based on the current gear position of the first synchronizer 105 and the target gear position of the second synchronizer 106.

[0127] In specific implementation, S202-1 may specifically include the following sub-steps:

[0128] S202-1-1: When the current gear position of the first synchronizer 105 is the power split gear position, determine that the gear ratio between the planet carrier 1044 and the ring gear 1041 is the second gear ratio.

[0129] It should be noted that different gear positions of the first synchronizer 105 correspond to different gear ratios. Specifically, when the first synchronizer 105 is in the power split gear position, the first synchronizer 105 is in the disengaged state. At this time, there is a second gear ratio greater than 1 between the planet carrier 1044 and the ring gear 1041, enabling the engine 101 to drive the vehicle faster; while when the first synchronizer 105 is in the engaged gear position, the first synchronizer 105 is in the locked state. At this time, the gear ratio between the planet carrier 1044 and the ring gear 1041 is 1:1, and the engine 101 will no longer transmit power to the transmission input shaft 107 through the ring gear 1041 to drive the vehicle.

[0130] S202-1-2: Based on the target gear position of the second synchronizer 106, determine that the gear ratio between the transmission input shaft 107 and the target wheel is the third gear ratio.

[0131] In this embodiment, different gear positions of the second synchronizer 106 correspond to different gear ratios. Continue to refer to Figure 1, where the forward gears include three gears D1, D2, and D3 with gradually decreasing gear ratios, and each gear has its corresponding gear ratio. During the mode switching process, the HCU will determine the target gear of the second synchronizer 106 based on the current vehicle speed and the driver's power demand, and then determine the gear ratio corresponding to the target gear. This gear ratio represents the gear ratio between the transmission input shaft 107 and the transmission output shaft 108. Therefore, by combining the gear ratio corresponding to the target gear and the gear ratio between the transmission output shaft 108 and the target wheel, the gear ratio between the transmission input shaft 107 and the target wheel can be calculated as the third gear ratio.

[0132] It should be noted that the target wheel refers to the wheel on the same side as the first motor 103. For example, when the first motor 103, the engine 101, and the transmission are arranged on the front axle of the vehicle, the target wheel refers to the front axle wheel. The current wheel speed can be determined based on the rotation speed signal collected by the wheel speed sensor; it can also be determined based on the current vehicle speed of the vehicle. 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.

[0133] S202-1-3: Determine the fourth gear ratio between the target wheel and the first motor 103 based on the second gear ratio, the first gear ratio, and the third gear ratio.

[0134] In this embodiment, based on the second gear ratio and the first gear ratio, the gear ratio between the sun gear 1042 and the ring gear 1041 can be calculated. Since the first motor 103 and the sun gear 1042 have the same rotation speed, and the ring gear 1041 and the transmission input shaft 107 have the same rotation speed, therefore, by further combining the third gear ratio, the fourth gear ratio between the target wheel and the first motor 103 can be calculated.

[0135] In a specific implementation, the fourth gear ratio between the target wheel and the first motor 103 can be calculated according to the following formula:

[0136] i4 = i1 × i2 × i3 (2);

[0137] Where, i4 represents the fourth gear ratio between the target wheel and the first motor 103, i1 represents the first gear ratio between the sun gear 1042 and the planet carrier 1044, i2 represents the gear ratio between the planet carrier 1044 and the ring gear 1041 as the second gear ratio, and i3 represents the gear ratio between the transmission input shaft 107 and the target wheel.

[0138] S202-1-4: Determine the target motor speed of the first motor 103 based on the fourth gear ratio and the current wheel speed of the target wheel.

[0139] In a specific implementation, the target motor speed of the first motor 103 can be calculated according to the following formula:

[0140] n = n0 × i4 (3);

[0141] Where n represents the target motor speed of the first motor 103, n0 represents the current wheel speed of the target wheel, and i4 represents the fourth gear ratio between the target wheel and the first motor 103.

[0142] S202-2: Based on the target motor speed, adjust the current motor speed of the first motor 103.

[0143] In this embodiment, when the HCU sends a speed control request to the motor controller, it will also send a speed control flag bit to the motor controller, so that the motor controller controls the first motor 103 to switch from the torque control mode to the speed control mode to achieve precise control of the motor speed.

[0144] In this embodiment, after the motor controller receives the speed control request and switches to the speed control mode, it will activate the PI (proportional-integral) speed loop for the first motor 103 to control the current motor speed of the first motor 103 to follow the target motor speed in a closed-loop control manner.

[0145] 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 is built-in with a 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, and a proportional adjustment value can be output; input the current motor speed and the first speed difference into the integral controller, and an integral adjustment value can be output; and then based on the proportional adjustment value and the integral adjustment value, adjust the speed of the first motor 103.

[0146] In this embodiment, by comprehensively considering the current gear position of the first synchronizer 105 and the target gear position of the second synchronizer 106, the accurate calculation of the target motor speed can be achieved. At the same time, through closed-loop control of the motor speed, the rapid and precise control of the current motor speed can be realized, thereby effectively balancing the speed difference at both ends of the second synchronizer 106 and ensuring that the second synchronizer 106 can be smoothly engaged into the target gear position.

[0147] It should be noted that after the vehicle completes the switching process from the series mode to the power split mode, the HCU will control the first motor 103 to exit the speed control mode and activate the torque control mode, so that the first motor 103 can stably output torque to achieve the purpose of stable power generation.

[0148] In a feasible implementation manner, the vehicle mode switching method may further include the following steps:

[0149] S401: When the current motor speed of the first motor 103 reaches the target motor speed, timing of a third duration during which the fluctuation amplitude of the current motor speed is less than a speed threshold is triggered.

[0150] In this embodiment, taking into account that the speed of the first motor 103 may fluctuate during the speed adjustment process, in order to ensure the smooth implementation of the gear shifting operation of the second synchronizer 106, the speed fluctuation of the first motor 103 will be detected based on a preset speed threshold to determine whether the current motor speed of the first motor 103 is in a stable state.

[0151] It should be noted that the shifting requirements of the second synchronizer 106 are different at different vehicle speeds. The higher the vehicle speed, the more drastic the speed change. Therefore, the corresponding speed threshold can be determined according to the current vehicle speed, wherein the speed threshold can decrease as the current vehicle speed increases. For example, when the current vehicle speed is less than or equal to 2km / h, the speed threshold can be set to 50rpm, and when the current vehicle speed is greater than 2km / h, the speed threshold can be set to 20rpm. In this way, by matching a lower speed threshold at a high vehicle speed, it can be further ensured that the second synchronizer 106 can shift smoothly when the vehicle is in motion.

[0152] In a specific implementation, after the HCU detects for the first time that the current motor speed reaches the target motor speed, it will trigger the timing of the third duration, wherein the third duration represents the duration of continuous and stable operation of the first motor 103 in the speed dimension.

[0153] S402 : When the third duration is greater than the third duration threshold, determine that the second synchronizer 106 satisfies the second gear shifting condition.

[0154] In this embodiment, when the third duration is greater than the third duration threshold, it indicates that the current motor speed of the first motor 103 fluctuates around the target motor speed with a fluctuation amplitude less than the speed threshold, that is, it is in a stable operating state.

[0155] In this embodiment, by monitoring the current motor speed during the speed adjustment of the first motor 103, it is possible to accurately determine whether the second synchronizer 106 meets the second gear switching conditions, thereby ensuring that the second synchronizer 106 can shift gears smoothly, effectively avoiding damage to the second synchronizer 106 and gear shift failure.

[0156] In a feasible implementation, S203 may specifically include the following sub-steps:

[0157] S203 - 1 : When the second synchronizer 106 satisfies the second gear shifting condition, the second synchronizer 106 is controlled to perform a pre-synchronization operation, so that the shift fork of the second synchronizer 106 moves to the pre-synchronization position.

[0158] It should be noted that the shift fork is a main part of the gearbox shift mechanism, which is used to shift the synchronizer ring to change the input / output speed ratio of the synchronizer to achieve the gear shifting effect. When the second synchronizer 106 is in the neutral state, the shift fork is in the original position, that is, the starting position of the shift fork, and the gear shifting of the second synchronizer 106 can be achieved by moving left and right.

[0159] In this embodiment, the pre-synchronization position refers to a position between the starting position of the shift fork and the target position. Preferably, the pre-synchronization position can be set at a position close to the target position to shorten the shifting time.

[0160] In a specific implementation, after determining that the second synchronizer 106 meets the second gear shifting condition, the HCU sends a synchronizer pre-synchronization request to the transmission controller, so that the transmission controller controls the synchronizer fork to move to the pre-synchronization position in response to the synchronizer pre-synchronization request.

[0161] S203-2: When it is determined that the shift fork of the second synchronizer 106 reaches the pre-synchronization position and the first torque difference between the current motor torque and the target motor torque is less than the fourth torque threshold, control the second synchronizer 106 to move from the pre-synchronization position to the target position so that the second synchronizer 106 switches to the target gear.

[0162] In this embodiment, after detecting that the shift fork of the second synchronizer reaches the pre-synchronization position, the HCU will monitor the current motor torque to determine whether the current motor torque is maintained in a stable state. In this way, the shift operation can be performed under the premise of ensuring that the current motor torque is maintained in a stable state, thereby ensuring the safety of the second synchronizer 106.

[0163] In the second aspect, based on the same inventive concept, refer to Figure 3, an embodiment of the present application provides a vehicle mode switching device 300, which is applied to a vehicle. The vehicle includes an engine 101, a clutch 102, a first motor 103, and a transmission. The transmission includes a power split mechanism 104, a transmission input shaft 107, a transmission output shaft 108, a first synchronizer 105, and a second synchronizer 106. The engine 101 is connected to the first input end of the power split mechanism 104 through the clutch 102. The first motor 103 is connected to the second input end of the power split mechanism 104. The output end of the power split mechanism 104 is connected to the transmission input shaft 107. The second synchronizer 106 is disposed between the transmission input shaft 107 and the transmission output shaft 108. The first synchronizer 105 is disposed between the first input end and the output end. The vehicle mode switching device 300 includes:

[0164] A torque adjustment module 301, configured to, in response to a mode switching request for switching from a series mode to a power split mode, keep the clutch 102 in a closed state, keep the engine 101 in a driving state, and adjust the current motor torque of the first motor 103 to enable the first synchronizer 105 to meet the first gear shifting condition;

[0165] A speed adjustment module 302, configured to, when the first synchronizer 105 meets the first gear shifting condition, control the first synchronizer 105 to switch from an engaged gear to a power split gear; and adjust the current motor speed of the first motor 103 to enable the second synchronizer 106 to meet the second gear shifting condition;

[0166] A gear shifting module 303, configured to, when the second synchronizer 106 meets the second gear shifting condition, control the second synchronizer 106 to switch from a neutral gear to a target gear, so that the vehicle switches from a series mode to a power split mode.

[0167] In an embodiment of the present application, the power split mechanism 104 includes a ring gear 1041, a sun gear 1042, a plurality of planet gears 1043 meshing between the ring gear 1041 and the sun gear 1042, and a planet carrier 1044 rotatably connected to the plurality of planet gears 1043. The planet carrier 1044 is connected to the engine 101. The sun gear 1042 is connected to the first motor 103. The ring gear 1041 is connected to the transmission input shaft 107. The first synchronizer 105 is disposed between the planet carrier 1044 and the ring gear 1041. The torque adjustment module 301 includes:

[0168] A target motor torque determination sub-module, configured to determine the target motor torque of the first motor 103 based on the current engine torque of the engine 101 and the first transmission ratio between the sun gear 1042 and the planet carrier 1044;

[0169] A torque adjustment sub-module, configured to adjust the current motor torque of the first motor 103 based on a target motor torque.

[0170] In an embodiment of the present application, the vehicle mode switching device 300 further includes:

[0171] A first timing module, configured to trigger timing of a first duration during which a first torque difference between the current motor torque and the target motor torque is less than a first torque threshold, and timing of a second duration during which a fluctuation amplitude of the current engine torque is less than a second torque threshold, when the first torque difference between the current motor torque and the target motor torque is less than the first torque threshold.

[0172] A first condition determination module, configured to determine that the first synchronizer 105 meets a first gear shifting condition when the first duration is greater than a first duration threshold and the second duration is greater than a second duration threshold.

[0173] In an embodiment of the present application, the speed adjustment module 302 includes:

[0174] A target motor speed determination sub-module, configured to determine a target motor speed of the first motor 103 based on a current gear of the first synchronizer 105 and a target gear of the second synchronizer 106.

[0175] A speed adjustment sub-module, configured to adjust the current motor speed of the first motor 103 based on the target motor speed.

[0176] In an embodiment of the present application, the target motor speed determination sub-module includes:

[0177] A first gear ratio determination unit, configured to determine a gear ratio between the planet carrier 1044 and the ring gear 1041 as a second gear ratio when the current gear of the first synchronizer 105 is a power split gear.

[0178] A second gear ratio determination unit, configured to determine a gear ratio between the transmission input shaft 107 and the target wheel as a third gear ratio based on the target gear of the second synchronizer 106.

[0179] A third gear ratio determination unit, configured to determine a fourth gear ratio between the target wheel and the first motor 103 based on the second gear ratio, the first gear ratio, and the third gear ratio.

[0180] A target motor speed determination unit, configured to determine the target motor speed of the first motor 103 based on the fourth gear ratio and the current wheel speed of the target wheel.

[0181] In an embodiment of the present application, the vehicle mode switching device 300 further includes:

[0182] A second timing module, configured to trigger timing of a third duration when the current motor speed of the first motor 103 reaches the target motor speed, where the fluctuation amplitude of the current motor speed is less than a speed threshold;

[0183] A second condition determination module, configured to determine that the second synchronizer 106 meets the second gear shifting condition when the third duration is greater than a third duration threshold.

[0184] In an embodiment of the present application, the gear shifting module 303 includes:

[0185] A pre-synchronization sub-module, configured to control the second synchronizer 106 to perform a pre-synchronization operation when the second synchronizer 106 meets the second gear shifting condition, so that the shift fork of the second synchronizer 106 moves to a pre-synchronization position;

[0186] A gear shifting sub-module, configured to control the second synchronizer 106 to move from the pre-synchronization position to a target position when it is determined that the shift fork of the second synchronizer 106 reaches the pre-synchronization position and the first torque difference between the current motor torque and the target motor torque is less than a fourth torque threshold, so that the second synchronizer 106 switches to the target gear.

[0187] It should be noted that the specific implementation manner of the vehicle mode switching device 300 in the embodiments of the present application refers to the specific implementation manner of the vehicle mode switching method proposed in the first aspect of the embodiments of the present application, which will not be elaborated here.

[0188] In a third aspect, based on the same inventive concept, referring to Figure 4 , an embodiment of the present application provides a vehicle mode switching system 400, which is applied to a vehicle. The vehicle includes an engine 101, a clutch 102, a first motor 103, and a gearbox; the gearbox includes a power split mechanism 104, a gearbox input shaft 107, a gearbox output shaft 108, a first synchronizer 105, and a second synchronizer 106. The engine 101 is connected to a first input end of the power split mechanism 104 through the clutch 102, the first motor 103 is connected to a second input end of the power split mechanism 104, an output end of the power split mechanism 104 is connected to the gearbox input shaft 107, the second synchronizer 106 is arranged between the gearbox input shaft 107 and the gearbox output shaft 108, and the first synchronizer 105 is arranged between the first input end and the output end; the vehicle mode switching system 400 includes a vehicle controller 401, a gearbox controller 402, a motor controller 403, and an engine controller 404.

[0189] The vehicle controller is configured to send a clutch state holding request to the transmission controller, an engine state holding request to the engine controller, and a torque adjustment request to the motor controller in response to a mode switching request for switching from the series mode to the power split mode;

[0190] The transmission controller is configured to keep the clutch 102 in a closed state in response to the clutch state holding request;

[0191] The engine controller is configured to keep the engine 101 in a driving state in response to the engine state holding request;

[0192] The motor controller is configured to adjust the current motor torque of the first motor 103 in response to the torque adjustment request, so that the first synchronizer 105 meets the first gear shifting condition;

[0193] The vehicle controller is further configured to control the transmission controller to switch the first synchronizer 105 from the engaged gear to the power split gear and send a speed adjustment request to the motor controller when the first synchronizer 105 meets the first gear shifting condition;

[0194] The motor controller is further configured to adjust the current motor speed of the first motor 103 in response to the speed adjustment request, so that the second synchronizer 106 meets the second gear shifting condition;

[0195] The vehicle controller is further configured to control the transmission controller to switch the second synchronizer 106 from the neutral gear to the target gear when the second synchronizer 106 meets the second gear shifting condition, so that the vehicle switches from the series mode to the power split mode.

[0196] It should be noted that the specific implementation of the vehicle mode switching system 400 in the embodiments of the present application refers to the specific implementation of the vehicle mode switching method proposed in the first aspect of the present application, which will not be elaborated here.

[0197] Fourthly, based on the same inventive concept, referring to Figure 5 , the embodiments of the present application provide a vehicle 500, including the vehicle mode switching system 400 proposed in the third aspect of the present application.

[0198] It should be noted that the specific implementation of the vehicle 500 in the embodiments of the present application refers to the specific implementation of the vehicle mode switching system 400 proposed in the third aspect of the embodiments of the present application, which will not be elaborated here.

[0199] Those skilled in the art should understand that the embodiments of the present invention can be provided as methods, devices, or computer program products. Therefore, the embodiments of the present invention can take the form of completely hardware embodiments, completely software embodiments, or embodiments combining software and hardware aspects. Moreover, the embodiments of the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memories, CD-ROMs, optical memories, etc.) that contain computer-usable program code.

[0200] The embodiments of the present invention are described with reference to the flowcharts and / or block diagrams of methods, terminal devices (systems), and computer program products according to the embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processors of general-purpose computers, special-purpose computers, embedded processors, or other programmable data processing terminal devices to generate a machine, such that the instructions executed by the processors of the computer or other programmable data processing terminal devices generate a device for implementing the functions specified in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0201] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing terminal device to work in a specific manner, such that the instructions stored in the computer-readable memory generate a manufactured article including an instruction device that implements the functions specified in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0202] These computer program instructions can also be loaded onto a computer or other programmable data processing terminal device, such that a series of operation steps are executed on the computer or other programmable terminal device to generate a computer-implemented process, so that the instructions executed on the computer or other programmable terminal device provide steps for implementing the functions specified in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0203] Although the preferred embodiments of the embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications once they know the basic creative concepts. Therefore, the appended claims are intended to be construed as including the preferred embodiments and all changes and modifications falling within the scope of the embodiments of the present invention.

[0204] Finally, it should also be noted that in this text, relational terms such as first and second are only used 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 term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, article or terminal device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or terminal device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or terminal device comprising the element.

[0205] The above has introduced in detail a vehicle mode switching method, device, system and vehicle provided by the present invention. Specific examples are used in this text to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A vehicle mode switching method, characterized in that, The vehicle includes an engine, a clutch, a first motor, and a transmission; the transmission includes a power split mechanism, a transmission input shaft, a transmission output shaft, a first synchronizer, and a second synchronizer. The engine is connected to a first input end of the power split mechanism through the clutch, the first motor is connected to a second input end of the power split mechanism, an output end of the power split mechanism is connected to the transmission input shaft, the second synchronizer is disposed between the transmission input shaft and the transmission output shaft, and the first synchronizer is disposed between the first input end and the output end; the method includes: In response to a mode switching request for switching from a series mode to a power split mode, keep the clutch in a closed state, keep the engine in a driving state, and perform torque adjustment on the current motor torque of the first motor so that the first synchronizer meets the first gear shifting condition; When the first synchronizer meets the first gear shifting condition, control the first synchronizer to switch from an engaged gear to a power split gear; and perform speed adjustment on the current motor speed of the first motor so that the second synchronizer meets the second gear shifting condition; When the second synchronizer meets the second gear shifting condition, control the second synchronizer to switch from a neutral gear to a target gear so that the vehicle switches from the series mode to the power split mode.

2. The vehicle mode switching method according to claim 1, characterized in that The power split mechanism includes a ring gear, a sun gear, a plurality of planet gears meshing between the ring gear and the sun gear, and a planet carrier rotatably connected to the plurality of planet gears; the planet carrier is connected to the engine as the first input end, the sun gear is connected to the first motor as the second input end, the ring gear is connected to the transmission input shaft as the output end, and the first synchronizer is disposed between the planet carrier and the ring gear; The step of performing torque adjustment on the current motor torque of the first motor includes: Based on the current engine torque of the engine and a first gear ratio between the sun gear and the planet carrier, determine the target motor torque of the first motor; Based on the target motor torque, perform torque adjustment on the current motor torque of the first motor.

3. The vehicle mode switching method according to claim 2, wherein The method further includes: When a first torque difference between the current motor torque and the target motor torque is less than a first torque threshold, trigger timing of a first duration for which the first torque difference is less than the first torque threshold and timing of a second duration for which a fluctuation amplitude of the current engine torque is less than a second torque threshold; When the first duration is greater than a first duration threshold and the second duration is greater than a second duration threshold, determine that the first synchronizer meets the first gear shifting condition.

4. The vehicle mode switching method according to claim 2, wherein The step of performing speed adjustment on the current motor speed of the first motor includes: Based on the current gear of the first synchronizer and the target gear of the second synchronizer, determine the target motor speed of the first motor; Based on the target motor speed, perform speed adjustment on the current motor speed of the first motor.

5. The vehicle mode switching method according to claim 4, wherein, The step of determining the target motor speed of the first motor based on the current gear position of the first synchronizer and the target gear position of the second synchronizer includes: When the current gear position of the first synchronizer is the power split gear position, determining that the transmission ratio between the planet carrier and the ring gear is the second transmission ratio; Based on the target gear position of the second synchronizer, determining that the transmission ratio between the transmission input shaft and the target wheel is the third transmission ratio; Based on the second transmission ratio, the first transmission ratio, and the third transmission ratio, determining the fourth transmission ratio between the target wheel and the first motor; Based on the fourth transmission ratio and the current wheel speed of the target wheel, determining the target motor speed of the first motor.

6. The vehicle mode switching method according to claim 4, wherein, The method further includes: When the current motor speed of the first motor reaches the target motor speed, triggering the timing of the third duration during which the fluctuation amplitude of the current motor speed is less than the speed threshold; When the third duration is greater than the third duration threshold, determining that the second synchronizer meets the second gear shift condition.

7. The vehicle mode switching method according to claim 2, wherein The step of controlling the second synchronizer to shift from the neutral gear to the target gear position when the second synchronizer meets the second gear shift condition includes: When the second synchronizer meets the second gear shift condition, controlling the second synchronizer to perform a pre-synchronization operation to move the shift fork of the second synchronizer to the pre-synchronization position; When it is determined that the shift fork of the second synchronizer reaches the pre-synchronization position and the first torque difference between the current motor torque and the target motor torque is less than the fourth torque threshold, controlling the second synchronizer to move from the pre-synchronization position to the target position so that the second synchronizer shifts to the target gear position.

8. A vehicle mode switching device, characterized in that, The vehicle includes an engine, a clutch, a first motor, and a transmission; the transmission includes a power split mechanism, a transmission input shaft, a transmission output shaft, a first synchronizer, and a second synchronizer. The engine is connected to the first input end of the power split mechanism through the clutch, the first motor is connected to the second input end of the power split mechanism, the output end of the power split mechanism is connected to the transmission input shaft, the second synchronizer is arranged between the transmission input shaft and the transmission output shaft, and the first synchronizer is arranged between the first input end and the output end; the device includes: A torque adjustment module, configured to, in response to a mode switch request for switching from the series mode to the power split mode, keep the clutch in a closed state, keep the engine in a driving state, and perform torque adjustment on the current motor torque of the first motor so that the first synchronizer meets the first gear shift condition; A speed adjustment module, configured to, when the first synchronizer meets the first gear shift condition, control the first synchronizer to shift from the engaged gear to the power split gear; and perform speed adjustment on the current motor speed of the first motor so that the second synchronizer meets the second gear shift condition; The gear shifting module is configured to control the second synchronizer to shift from neutral to the target gear when the second synchronizer meets the second gear shifting condition, so that the vehicle switches from the series mode to the power split mode.

9. A vehicle mode switching system, characterized in that, The vehicle includes an engine, a clutch, a first motor, and a transmission; the transmission includes a power split mechanism, a transmission input shaft, a transmission output shaft, a first synchronizer, and a second synchronizer. The engine is connected to the first input end of the power split mechanism through the clutch, the first motor is connected to the second input end of the power split mechanism, the output end of the power split mechanism is connected to the transmission input shaft, the second synchronizer is arranged between the transmission input shaft and the transmission output shaft, and the first synchronizer is arranged between the first input end and the output end; the system includes a vehicle controller, a transmission controller, a motor controller, and an engine controller; wherein, The vehicle controller is configured to send a clutch state holding request to the transmission controller, an engine state holding request to the engine controller, and a torque adjustment request to the motor controller in response to a mode switching request for switching from the series mode to the power split mode; The transmission controller is configured to keep the clutch in a closed state in response to the clutch state holding request; The engine controller is configured to keep the engine in a driving state in response to the engine state holding request; The motor controller is configured to adjust the current motor torque of the first motor in response to the torque adjustment request, so that the first synchronizer meets the first gear shifting condition; The vehicle controller is further configured to control the transmission controller to shift the first synchronizer from the engaged gear to the power split gear and send a speed adjustment request to the motor controller when the first synchronizer meets the first gear shifting condition; The motor controller is further configured to adjust the current motor speed of the first motor in response to the speed adjustment request, so that the second synchronizer meets the second gear shifting condition; The vehicle controller is further configured to control the transmission controller to shift the second synchronizer from neutral to the target gear when the second synchronizer meets the second gear shifting condition, so that the vehicle switches from the series mode to the power split mode.

10. A vehicle, characterized in that, It includes the vehicle mode switching system as claimed in claim 9.

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