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, when a second synchronizer is in a reverse gear, in response to a mode switching request for switching from a power dividing mode to a series connection mode, a clutch is kept in a closed state, and a first motor is kept in a power generation state; the torque of the engine is adjusted, so that when the second synchronizer meets the first gear switching condition, the second synchronizer can be controlled to be switched to the neutral gear from the reverse gear; and the rotating speed of the first motor is adjusted, so that the first synchronizer is switched from the power split gear to the combined gear. According to the embodiment of the invention, the gear shifting operation of the second synchronizer and the first synchronizer can be completed in sequence on the premise that the clutch is not opened and power generation of the first motor is kept, the mode switching duration is effectively shortened while the charging requirement of the power battery is met, and the power response performance of the vehicle in the mode switching process is improved.

Description

Technical Field

[0001] The present 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 of energy conservation, emission reduction and carbon balance, traditional fuel vehicles are gradually moving towards hybrid vehicles. In order 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 the vehicle driving process, according to the changes in road conditions and driving requirements, the driving modes will switch to each other under certain conditions.

[0003] In the related art, during the process of the vehicle switching from the power split mode to the series mode in the reverse state, generally, the vehicle 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 switching. However, due to the process of opening and closing the clutch, this method will not only cause the engine to be unable to drive the motor to charge the power battery after the clutch is opened, but also cause problems such as a long mode switching time and untimely engine power response, thereby affecting the power response performance of the vehicle during the mode switching process. Summary of the Invention

[0004] The present application provides a vehicle mode switching method, device, system and vehicle to solve the problems that the charging process of the power battery is interrupted and the overall vehicle power response performance is poor when the current hybrid vehicle switches from the power split mode to the series mode in the reverse state.

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

[0006] In a first aspect, an embodiment of the present 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] When the second synchronizer is in the reverse gear, in response to a mode switching request to switch from the power split mode to the series mode, keep the clutch closed, keep the first motor in the power generation state, and adjust the torque of the engine so that the second synchronizer meets the first gear switching condition;

[0008] When the second synchronizer meets the first gear switching condition, control the second synchronizer to switch from the reverse gear to the neutral gear; and adjust the speed of the first motor so that the first synchronizer meets the second gear switching condition;

[0009] When the first synchronizer meets the second gear switching condition, control the first synchronizer to switch from the power split gear to the engaged gear so that the vehicle switches from the power split mode to the series 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 torque of the engine includes:

[0012] When the current gear of the first synchronizer is the power split gear, determine that the speed ratio between the sun gear and the planet carrier is the first speed ratio;

[0013] Based on the current motor torque of the first motor and the first speed ratio, determine the target engine torque of the engine;

[0014] Based on a preset torque adjustment gradient, control the current engine torque of the engine to gradually decrease to the target engine torque.

[0015] In an embodiment of the present application, the vehicle further includes a second motor, and the method further includes:

[0016] Based on the current engine torque and the current motor torque, determine the compensation torque of the second motor;

[0017] Based on the compensation torque and the current drive torque of the second motor, determine the target drive torque of the second motor;

[0018] During the process of torque adjustment of the engine, based on the torque adjustment gradient, control the second motor to gradually increase from the current driving torque to the target driving torque.

[0019] In an embodiment of the present application, the method further includes:

[0020] When the torque difference between the current engine torque and the target engine torque of the engine is less than the torque threshold, trigger timing of the duration during which the torque difference is less than the torque threshold;

[0021] When the duration is greater than the duration threshold, determine that the second synchronizer meets the first gear shifting condition.

[0022] In an embodiment of the present application, the step of adjusting the speed of the first motor includes:

[0023] Based on the current engine speed of the engine and the first speed ratio, determine the target motor speed of the first motor;

[0024] Control the current motor speed of the first motor to follow the target motor speed.

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

[0026] Based on the current motor speed and the second speed ratio between the ring gear and the sun gear, determine the current ring gear speed of the ring gear;

[0027] Based on the current engine speed, determine the current carrier speed of the carrier;

[0028] When the speed difference between the current ring gear speed and the current carrier speed is less than the speed difference threshold, determine that the first synchronizer meets the second gear shifting condition.

[0029] In an embodiment of the present application, the step of controlling the first synchronizer to switch from the power split gear to the engaged gear so that the vehicle switches from the power split mode to the series mode includes:

[0030] When the first synchronizer meets the second gear shifting condition, determine the sum of the current motor torque of the first motor and the preset shift-in assist torque as the target motor torque;

[0031] Control the current motor torque of the first motor to follow the target motor torque to assist the first synchronizer to switch from the power split gear to the engaged gear.

[0032] 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 arranged between the transmission input shaft and the transmission output shaft. The first synchronizer is arranged between the first input end and the output end. The device includes:

[0033] A torque adjustment module, configured to, when the second synchronizer is in the reverse gear, in response to a mode switching request for switching from a power split mode to a series mode, keep the clutch in a closed state, keep the first motor in a power generation state, and adjust the torque of the engine to enable the second synchronizer to meet a first gear switching condition;

[0034] A speed adjustment module, configured to, when the second synchronizer meets the first gear switching condition, control the second synchronizer to switch from the reverse gear to the neutral gear; and adjust the speed of the first motor to enable the first synchronizer to meet a second gear switching condition;

[0035] A mode switching module, configured to, when the first synchronizer meets the second gear switching condition, control the first synchronizer to switch from the power split gear to the engaged gear, so that the vehicle switches from the power split mode to the series mode.

[0036] 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. The first synchronizer is arranged between the planet carrier and the ring gear;

[0037] The torque adjustment module includes:

[0038] A gear ratio determination sub-module, configured to, when the current gear of the first synchronizer is the power split gear, determine that the gear ratio between the sun gear and the planet carrier is a first gear ratio;

[0039] An engine torque determination sub-module, configured to determine the target engine torque of the engine based on the current motor torque of the first motor and the first gear ratio;

[0040] An engine torque control sub-module, configured to control the current engine torque of the engine to gradually decrease to the target engine torque based on a preset torque adjustment gradient.

[0041] In an embodiment of the present application, the vehicle mode switching device further includes:

[0042] A compensation torque determination module, configured to determine the compensation torque of the second motor based on the current engine torque and the current motor torque;

[0043] A driving torque determination module, configured to determine the target driving torque of the second motor based on the compensation torque and the current driving torque of the second motor;

[0044] A driving torque control module, configured to control the second motor to gradually increase from the current driving torque to the target driving torque based on the torque adjustment gradient during the process of adjusting the torque of the engine.

[0045] In an embodiment of the present application, the vehicle mode switching device further includes:

[0046] A timing module, configured to trigger timing of the duration during which the torque difference between the current engine torque and the target engine torque of the engine is less than a torque threshold when the torque difference is less than the torque threshold;

[0047] A first condition determination module, configured to determine that the second synchronizer meets the first gear shifting condition when the duration is greater than a duration threshold.

[0048] In an embodiment of the present application, the speed regulation module includes:

[0049] A motor speed determination sub-module, configured to determine the target motor speed of the first motor based on the current engine speed of the engine and the first speed ratio;

[0050] A motor speed control sub-module, configured to control the current motor speed of the first motor to follow the target motor speed.

[0051] In an embodiment of the present application, the vehicle mode switching device further includes:

[0052] A ring gear speed determination module, configured to determine the current ring gear speed of the ring gear based on the current motor speed and the second speed ratio between the ring gear and the sun gear;

[0053] A carrier speed determination module, configured to determine the current carrier speed of the carrier based on the current engine speed;

[0054] A second condition determination module, configured to determine that the first synchronizer meets the second gear shifting condition when a rotational speed difference between the current ring gear rotational speed and the current carrier rotational speed is less than a rotational speed difference threshold.

[0055] In an embodiment of the present application, the mode switching module includes:

[0056] A motor torque determination sub-module, configured to determine a target motor torque as the sum of the current motor torque of the first motor and a preset shift-in auxiliary torque when the first synchronizer meets the second gear shifting condition;

[0057] A gear shifting sub-module, configured to control the current motor torque of the first motor to follow the target motor torque to assist the first synchronizer to switch from the power split gear to the engaged gear.

[0058] 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 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 system includes a vehicle controller, a transmission controller, a motor controller, and an engine controller. Among them,

[0059] The vehicle controller is configured to, when the second synchronizer is in the reverse gear, in response to a mode switching request for switching from the power split mode to the series mode, send an engine torque adjustment request to the engine controller, send a clutch state holding request to the transmission controller, and send a motor state holding request to the motor controller;

[0060] The transmission controller is configured to, in response to the clutch state holding request, keep the clutch in a closed state; the motor controller is configured to, in response to the motor state holding request, keep the first motor in a power generation state;

[0061] The engine controller is configured to, in response to the engine torque adjustment request, perform torque adjustment on the engine so that the second synchronizer meets the first gear shifting condition;

[0062] The vehicle controller is further configured to, when the second synchronizer meets the first gear shifting condition, send a first shifting request to the transmission controller and send a motor speed regulation request to the motor controller;

[0063] The transmission controller is further configured to, in response to the first shifting request, control the second synchronizer to shift from the reverse gear to the neutral gear; the motor controller is further configured to, in response to the motor speed regulation request, regulate the speed of the first motor so that the first synchronizer meets the second gear shifting condition;

[0064] The vehicle controller is further configured to, when the first synchronizer meets the second gear shifting condition, send a second shifting request to the transmission controller;

[0065] The transmission controller is further configured to, in response to the second shifting request, control the first synchronizer to shift from the power split gear to the engaged gear, so that the vehicle switches from the power split mode to the series mode.

[0066] 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.

[0067] Compared with the prior art, the present application has the following advantages:

[0068] A vehicle mode switching method provided by an embodiment of the present application can, when the second synchronizer is in the reverse gear, in response to a mode switching request for switching from the power split mode to the series mode, keep the clutch in the closed state and the first motor in the power generation state, and adjust the torque of the engine, so that when the second synchronizer meets the first gear shifting condition, the second synchronizer can be controlled to shift from the reverse gear to the neutral gear; and by adjusting the speed of the first motor, when the first synchronizer meets the second gear shifting condition, the first synchronizer can be controlled to shift from the power split gear to the engaged gear, so that the vehicle switches from the power split mode to the series mode. In the embodiment of the present application, by adjusting the torque of the engine and then adjusting the speed of the first motor, during the vehicle mode switching process, the shifting operations of the second synchronizer and the first synchronizer can be sequentially completed on the premise of not opening the clutch and keeping the first motor in the power generation state. In this way, the engine can not only continuously drive the first motor to charge the power battery, but also enable the vehicle to switch from the power split mode to the series mode more quickly and smoothly in the reverse state. While meeting the charging requirements of the power battery, the mode switching duration is effectively shortened, so that the engine can quickly output torque and improve the power response performance of the vehicle during the mode switching process. Description of the Drawings

[0069] 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.

[0070] Figure 1 is a schematic structural diagram of a hybrid vehicle in an embodiment of the present application.

[0071] Figure 2 is a flowchart of the steps of a vehicle mode switching method in an embodiment of the present application.

[0072] Figure 3 is a schematic diagram of the functional modules of a vehicle mode switching device in an embodiment of the present application.

[0073] Figure 4 is a schematic structural diagram of a vehicle mode switching system in an embodiment of the present application.

[0074] Figure 5 is a schematic structural diagram of a vehicle in an embodiment of the present application. Detailed implementation manners

[0075] 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.

[0076] 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 vehicle front axle; 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.

[0077] 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 the engaged gear position, 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 the neutral position, the second synchronizer 106 is used to disconnect the transmission input shaft 107 and the transmission output shaft 108.

[0078] 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 position, 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 position, 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 position, the vehicle can be in the power split mode; when the first synchronizer 105 is in the engaged gear position, 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, etc.

[0079] Furthermore, 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) at the rear axle of the vehicle, 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.

[0080] Since the hybrid vehicle adopting the above architecture is configured with the power split mechanism 104, and the power split mechanism 104 is respectively 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 positions of the first synchronizer 105 and the second synchronizer 106, the vehicle can be switched between different driving modes. Specifically:

[0081] 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.

[0082] 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. It should be noted that since all the driving force of the engine 101 in the series mode is used to drive the first motor 103 to generate electricity, therefore, the charging power of the power battery in the series mode is usually greater than the charging power in the power split mode.

[0083] In the related art, after a hybrid vehicle completes reverse driving in the power split mode, it is necessary to switch the vehicle from the power split mode to the series mode. However, in the traditional vehicle mode switching strategy, the vehicle needs to first disengage the clutch 104, then perform torque reduction and speed regulation operations on the engine 101, and then re-engage the clutch 104 after the torque reduction and speed regulation operations are completed to complete the mode switching. However, since there is a process of opening and closing the clutch 104 in this method, not only will the engine 101 be unable to drive the first motor 103 to charge the power battery after the clutch 104 is opened, but also problems such as a long mode switching time and untimely power response of the engine 101 will occur, thereby affecting the power response performance of the vehicle during mode switching.

[0084] Aiming at the problems that the power battery charging is interrupted and the vehicle power response performance is poor when the current hybrid vehicle switches from the power split mode to the series mode in the reverse state. The present application aims to provide a vehicle mode switching method, device, system and vehicle, which can keep the clutch 102 in a closed state, the first motor 103 in a power generation state, and adjust the torque of the engine 101, and then adjust the speed of the first motor 103, so that during the vehicle mode switching process, without opening the clutch 102, the gear shifting operations of the second synchronizer 106 and the first synchronizer 105 can be completed in sequence. In this way, the engine 101 can not only continuously drive the first motor 103 to charge the power battery, but also enable the vehicle to switch from the power split mode to the series mode more quickly and smoothly in the reverse state. While meeting the charging requirements of the power battery, the mode switching duration is effectively shortened, so that the engine 101 can quickly output torque and improve the power response performance of the vehicle during mode switching.

[0085] Refer to Figure 2 , which shows a vehicle mode switching method of the present application, applied to a hybrid vehicle adopting the above architecture. The method may include the following steps:

[0086] S201: When the second synchronizer 106 is in the reverse gear, in response to a mode switching request for switching from the power split mode to the series mode, keep the clutch 102 in a closed state, the first motor 103 in a power generation state, and adjust the torque of the engine 101 so that the second synchronizer 106 meets the first gear switching condition.

[0087] 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), BCM (Body Control Module), HCU (Vehicle Control Unit), etc. This embodiment will take the HCU as the execution entity for description. It should be noted that this embodiment does not make specific restrictions on the execution entity of the vehicle.

[0088] In this embodiment, when the second synchronizer 106 is in the reverse gear, that is, when the vehicle is in the reverse state, the HCU can monitor by obtaining the gear lever information of the vehicle and the SOC (State of Charge, battery charge state, also known as the remaining power) of the power battery to determine whether the vehicle needs to switch from the power split mode to the series mode.

[0089] In a specific implementation, if the HCU detects that the current remaining power of the power battery is less than the power threshold and the gear lever information indicates that the gear lever position has switched from the R gear (reverse gear) to the P gear (parking gear) or the N gear (neutral gear), it means that the power battery has a charging requirement and the driver intends to end the reverse. At this time, to avoid power battery discharge, the vehicle will automatically trigger a mode switch request to switch from the power split mode to the series mode.

[0090] In this embodiment, the HCU will respond to the mode switch 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 102 in the closed state; at the same time, send a motor state holding request to the motor controller, so that the motor controller responds to the motor state holding request and keeps the first motor 103 in the power generation state, that is, keeps the original power generation torque unchanged; at the same time, also send an engine torque adjustment request to the engine controller, so that the engine controller responds to the engine torque adjustment request and adjusts the torque of the engine 101.

[0091] It should be noted that the second synchronizer 106 is arranged between the transmission input shaft 107 and the transmission output shaft 108. When in the in-gear state, it can be used to realize the torque transmission between the transmission input shaft 107 and the transmission output shaft 108; when in the neutral state, it can be used to cut off the torque transmission between the transmission input shaft 107 and the transmission output shaft 108. When the vehicle is in the power split mode, the second synchronizer 106 is in the reverse gear. At this time, a part of the driving force output by the engine 101 can be transmitted to the front axle wheels through the second synchronizer 106. At this time, the reverse gear rotates in reverse, and the vehicle can be reversed. When the vehicle switches from the power split mode to the series mode, the second synchronizer 106 needs to be shifted to the neutral gear. Then, the driving force output by the engine 101 will no longer directly drive the vehicle to travel, but all be used to drive the first motor 103 to generate electricity.

[0092] In this embodiment, to prevent the second synchronizer 106 from being unable to shift gears or being damaged during gear shifting, the HCU will adjust the torque applied to the second synchronizer 106 to a smaller value, ideally zero.

[0093] In this embodiment, considering that when the clutch 102 is closed, the torques of the engine 101 and the first motor 103 can be simultaneously applied to the second synchronizer 106 through the power split mechanism 104. Therefore, by adjusting the torque of the engine 101, it is possible to effectively balance the torques of the engine 101 and the first motor 103 acting on the second synchronizer 106 on the premise of keeping the output torque of the first motor 103 unchanged, and then realize the torque adjustment of the second synchronizer 106. In this way, it is possible to reduce the torque at the second synchronizer 106 to the torque required for closing without opening the clutch 102 and interrupting the power generation of the first motor 103, so that the second synchronizer 106 meets the first gear shifting condition.

[0094] In an example, if the HCU detects that the engine 101 outputs 800 N·m to the power split mechanism 104 and the first motor 103 outputs -300 N·m to the power split mechanism 104, it will control the first motor 103 to continue to output -300 N·m for power generation, and control the current engine torque of the engine 101 to be reduced from 800 N·m to 300 N·m. In this way, not only can the gear shifting requirements of the second synchronizer 106 be met, but also the first motor 103 can be kept in the power generation state.

[0095] S202: When the second synchronizer 106 meets the first gear shifting condition, control the second synchronizer 106 to shift from the reverse gear to the neutral gear; and adjust the speed of the first motor 103 to make the first synchronizer 105 meet the second gear shifting condition.

[0096] In this embodiment, after the HCU detects that the second synchronizer 106 meets the first gear shifting condition and the current gear is in the engaged state, it will send a first gear shifting request indicating that the target gear is neutral to the transmission controller, so that the transmission controller responds to the first gear shifting request and controls the second synchronizer 106 to disengage from the reverse gear to neutral.

[0097] In this embodiment, if the HCU detects that the second synchronizer 106 has been switched to neutral, it will trigger the speed regulation of the first motor 103 and send a motor speed regulation request including the target motor speed to the motor controller, so that the motor controller responds to the motor speed regulation request and adjusts the current motor speed of the first motor 103 to make the first synchronizer 105 meet the second gear shifting condition.

[0098] It should be noted that the first synchronizer 105 is arranged between the first input end and the output end of the power split mechanism 104. Since the output end is connected to the transmission input shaft 107, the first synchronizer 105 can be used to adjust the gear ratio between the first input end of the power split mechanism 104 and the transmission input shaft 107.

[0099] In the power split mode, the first synchronizer 105 is in the power split gear. At this time, the gear ratio between the power split mechanism 104 and the transmission input shaft 107 is usually set to a value greater than 1, such as 2:1. When the vehicle switches from the power split mode to the series mode, the first synchronizer 105 needs to be shifted to the engaged gear. At this time, the first input end and the output end of the power split mechanism 104 are in the locked state, and the output end is connected to the transmission input shaft 107, so that the gear ratio between the first input end and the transmission input shaft 107 is 1:1. To avoid damage to the first synchronizer 105 during gear shifting, it is required that the speed difference between both ends of the first synchronizer 105 is a small value, and ideally it is zero.

[0100] In this embodiment, considering that the first motor 103 is connected to the power split mechanism 104 and the torque balance at the first synchronizer 105 has been achieved through the engine 101 and the first motor 103, therefore, by adjusting the speed of the first motor 103, it is also possible to adjust the speeds of both ends of the first synchronizer 105 while keeping the clutch 102 closed, so that the first synchronizer 105 meets the second gear shifting condition.

[0101] S203: When the first synchronizer 105 meets the second gear shifting condition, control the first synchronizer 105 to switch from the power split gear to the engaged gear, so that the vehicle switches from the power split mode to the series mode.

[0102] In this embodiment, after the HCU detects that the first synchronizer 105 meets the second gear shifting condition and the current gear is the power split gear, it will send a second gear shifting request indicating that the target gear is the engaged gear to the transmission controller, so that the transmission controller responds to the second gear shifting request and controls the second synchronizer 106 to shift from the power split gear to the neutral gear.

[0103] In this embodiment, after the HCU determines that the first synchronizer 105 has shifted to the engaged gear, it will set the current driving mode of the vehicle from the power split mode to the series mode, and then adjust the speeds of the engine 101 and the first motor 103 according to the speed control strategy in the series mode, so that the engine 101 drives the first motor 103 to generate electricity stably.

[0104] Specifically, the HCU will execute a preset speed control strategy, control the current engine speed of the engine 101 to increase or decrease to a preset first target power generation speed, and at the same time control the current motor speed of the first motor 103 to increase or decrease to a preset second target power generation speed. Among them, the first target power generation speed represents the engine speed that can make the engine 101 operate in the optimal working range and meet the charging demand of the first motor 103; the second target power generation speed represents the motor speed at which the first motor 103 can stably output the target power generation voltage. In this way, the driving force output by the engine 101 can be transmitted to the first motor 103 through the power split mechanism 104 to drive the first motor 103 to generate electricity stably.

[0105] In this embodiment, the HCU will also execute a preset energy management strategy to determine a first energy distribution ratio for the power battery and a second energy distribution ratio for the second motor according to the current SOC of the power battery and the power demand triggered by the driver; and then control the first motor 103 to charge the power battery according to the first energy distribution ratio, and control the first motor 103 to supply power to the second motor according to the second energy distribution ratio. Specifically, the first energy distribution ratio can be set to decrease as the current SOC increases, and when the current SOC reaches a preset charging cut-off threshold, the first energy distribution ratio decreases to zero.

[0106] In the embodiment of the present application, by adjusting the torque of the engine 101, the shifting operation of the second synchronizer 106 can be realized while keeping the first motor 103 in the power generation state, and by adjusting the speed of the first motor 103, the shifting operation of the first synchronizer 105 can be realized without opening the clutch 102. In this way, the vehicle can switch from the power split mode to the series mode more quickly and smoothly in the reverse state. On the one hand, the engine 101 can not only continuously drive the first motor 103 to charge the power battery to meet the charging requirements of the power battery; on the other hand, it can effectively shorten the mode switching duration, so that the engine 101 can quickly output torque and improve the power response performance of the vehicle during mode switching.

[0107] In a feasible embodiment, with continued reference to Figure 1 , the power split mechanism 104 may specifically 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 split mechanism 104, the sun gear 1042 is connected to the first motor 103 as the second input end of the power split mechanism 104, the ring gear 1041 is connected to the transmission input shaft 107 as the output end of the power split mechanism 104, and the first synchronizer 105 is arranged between the planet carrier 1044 and the ring gear 1041.

[0108] In the series mode, the first synchronizer 105 is in the engaged gear and the second synchronizer 106 is in the neutral gear. 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, 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 to travel.

[0109] In the power split mode, the first synchronizer 105 is in the power split 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. The planet carrier 1044 will transmit a part of the driving force to the first motor 103 through a 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 a 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 to travel.

[0110] Based on the above structure, the steps of torque adjustment for the engine 101 in S201 may specifically include the following sub-steps:

[0111] S201-1: When the current gear position of the first synchronizer 105 is the power split gear position, determine that the speed ratio between the sun gear 1042 and the planet carrier 1044 is the first speed ratio.

[0112] It should be noted that since the first synchronizer 105 has different speed ratios between the planet carrier 1044 and the ring gear 1041 in different gear positions, and the sun gear 1042 has the same speed as the first motor 103, and the planet carrier 1044 has the same speed as the engine, therefore, based on the current gear position of the first synchronizer 105, the speed ratio between the first motor 103 and the engine 101 can be determined.

[0113] In this embodiment, since the current gear position of the first synchronizer 105 is the power split gear position before shifting, the HCU will determine that the speed ratio between the sun gear 1042 and the planet carrier 1044 is the first speed ratio.

[0114] S201-2: Based on the current motor torque of the first motor 103 and the first speed ratio, determine the target engine torque of the engine 101.

[0115] In this embodiment, since the speed and torque are in an inverse proportional relationship, the HCU will control the current motor torque of the first motor 103 to remain unchanged, and based on the first speed ratio and the current motor torque of the first motor 103, the target engine torque of the engine 101 can be calculated inversely.

[0116] S201-3: Based on the preset torque adjustment gradient, control the current engine torque of the engine 101 to gradually decrease to the target engine torque.

[0117] In this embodiment, after the HCU determines the target engine torque, it will activate the torque control mode of the engine controller so that the engine controller adjusts the current engine torque of the engine 101 to the target engine torque.

[0118] In a specific implementation, the current engine torque of the engine 101 can be controlled to gradually reach the target engine torque according to a preset torque adjustment gradient. Among them, the torque adjustment gradient represents the change amount of torque per unit time. For example, it can be set to 200 N·m / s.

[0119] In this embodiment, by adjusting the torque of the engine 101 according to the torque adjustment gradient, it is possible to avoid excessive torque changes from affecting the driving smoothness of the vehicle.

[0120] In a feasible embodiment, the vehicle further includes a second motor, and the vehicle mode switching method may further include the following steps:

[0121] S301: Determine the compensation torque of the second motor based on the current engine torque and the current motor torque.

[0122] In this embodiment, considering that during the process of adjusting the torque of the engine 101, the front axle torque will continuously decrease. To ensure the power demand of the whole vehicle during the mode switching process, torque compensation will be performed through the second motor.

[0123] In this embodiment, since the current motor torque is a negative torque and is used to offset a part of the positive torque of the current engine torque, the HCU can determine the sum of the current engine torque and the current motor torque as the compensation torque of the second motor.

[0124] It should be noted that the current engine torque represents the engine torque before the torque of the engine 101 is adjusted; the current motor torque represents the motor torque before the torque of the engine 101 is adjusted.

[0125] Exemplarily, before adjusting the torque of the engine 101, if the current engine torque is 800 N·m and the current motor torque is -300 N·m, the compensation torque of the second motor is 500 N·m.

[0126] S302: Determine the target drive torque of the second motor based on the compensation torque and the current drive torque of the second motor.

[0127] In this embodiment, the HCU will further superimpose the compensation torque on the basis of the current drive torque of the second motor so that the second motor supplements the reduced torque of the vehicle front axle at the vehicle rear axle.

[0128] S303: During the process of torque adjustment for the engine 101, based on the torque adjustment gradient, control the second motor to gradually increase from the current driving torque to the target driving torque.

[0129] In this embodiment, during the process of torque adjustment for the engine 101 according to the torque adjustment gradient, the HCU will also synchronously control the second motor to perform torque compensation according to the same torque adjustment gradient.

[0130] In one example, the torque adjustment gradient is set to 200 N·m / s. If the HCU detects that the engine 101 outputs 800 N·m, the first motor 103 outputs -300 N·m, and the second motor outputs 400 N·m, it will, in response to the mode switching request, control the engine 101 to gradually decrease from 800 N·m to 300 N·m according to the torque adjustment gradient of 200 N·m / s; at the same time, control the second motor to gradually increase from 400 N·m to 900 N·m.

[0131] In this embodiment, torque compensation is performed by the second motor, so that during the mode switching process, the vehicle power performance can be kept consistent, thereby effectively meeting the driver's power demand during the mode switching process, and at the same time avoiding phenomena such as abnormal deceleration or jerks of the vehicle.

[0132] In a feasible embodiment, the vehicle mode switching method may further include the following steps:

[0133] S401: When the torque difference between the current engine torque and the target engine torque of the engine 101 is less than the torque threshold, trigger the timing of the duration during which the torque difference is less than the torque threshold.

[0134] In this embodiment, during the process of torque adjustment for the engine 101 by the HCU, it will obtain the current engine torque real-time feedback by the engine controller, and then when detecting that the torque difference between the current engine torque and the target engine torque is less than the torque threshold, trigger the cumulative timing of the duration by the timer, and then based on the duration, determine whether the engine 101 is stably operating at the target engine torque.

[0135] S402: When the duration is greater than the first duration threshold, determine that the second synchronizer 106 meets the first gear shifting condition.

[0136] In this embodiment, if the HCU detects that the duration is greater than the duration threshold, it is considered that the engine 101 is stably operating at the target engine torque, and then determine that the second synchronizer 106 meets the first gear shifting condition.

[0137] In this embodiment, by monitoring the duration, it is possible to effectively avoid controlling the second synchronizer 106 to shift out of gear when the engine 101 has abnormal torque fluctuations, thereby ensuring that the second synchronizer 106 can shift gears smoothly.

[0138] In a feasible embodiment, the step of adjusting the speed of the first motor 103 in S202 may specifically include the following sub-steps:

[0139] S202-1: Determine the target motor speed of the first motor 103 based on the current engine speed of the engine 101 and the first gear ratio.

[0140] It should be noted that since the first synchronizer 105 is arranged between the planet carrier 1044 and the ring gear 1041, it is necessary to adjust the speeds of the planet carrier 1044 and the ring gear 1041 so that the speed difference at both ends of the first synchronizer 105 is less than a preset shifting threshold. And since the planet carrier 1044 is connected to the engine 101, the speed of the planet carrier 1044 can be equivalent to the engine speed; also, since the ring gear 1041 is connected through a plurality of planet gears 1043, the sun gear 1042, and the first motor 103, the speed of the ring gear 1041 can be equivalently converted based on the speed of the first motor 103. Thus, by adjusting the speed of the first motor 103, the speeds at both ends of the first synchronizer 105 can be adjusted to enable the first synchronizer 105 to meet the second gear shifting condition.

[0141] In this embodiment, the HCU will use the current engine speed of the engine 101 as the speed regulation reference. Thus, by adjusting the speed of the first motor 103, the first synchronizer 105 can meet the second gear shifting condition without adjusting the engine speed.

[0142] In specific implementation, the first gear ratio can be calculated based on the gear ratio between the planet carrier 1044 and the ring gear 1041 being the first gear ratio and the third gear ratio between the ring gear 1041 and the sun gear 1042. Then, based on the current engine speed of the engine 101 and the first gear ratio, the target motor speed of the first motor 103 can be calculated.

[0143] S202-2: Control the current motor speed of the first motor 103 to follow the target motor speed.

[0144] In this embodiment, after the HCU calculates the target motor speed, when sending a speed control request including the target motor speed to the motor controller, it will also send a speed control flag bit to the motor controller, so that the motor controller can control the first motor 103 to switch from the torque control mode to the speed control mode to achieve precise control of the speed of the first motor 103.

[0145] In this embodiment, after the motor controller receives a 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.

[0146] 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, the speed of the first motor 103 is adjusted.

[0147] In this embodiment, by comprehensively considering the current gear position of the first synchronizer 105 and the transmission ratio between the first motor 103 and the engine 101, the accurate calculation of the target motor speed can be achieved. At the same time, through the closed-loop control of the motor speed, the rapid and accurate control of the current motor speed can be realized, and then the speed difference at both ends of the first synchronizer 105 can be effectively balanced, ensuring that the first synchronizer 105 can be smoothly engaged into the target gear position.

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

[0149] S501: Determine the current ring gear speed of the ring gear 1041 based on the current motor speed and the second transmission ratio between the ring gear 1041 and the sun gear 1042.

[0150] In this embodiment, since the first motor 103 is connected to the sun gear 1042, based on the current motor speed and the second transmission ratio between the ring gear 1041 and the sun gear 1042, the current ring gear speed of the ring gear 1041 can be calculated in real time.

[0151] S502: Determine the current carrier speed of the planet carrier 1044 based on the current engine speed.

[0152] In this embodiment, since the engine 101 is connected to the planet carrier 1044, the current engine speed can be directly determined as the current carrier speed.

[0153] S503: When the speed difference between the current ring gear speed and the current carrier speed is less than the speed difference threshold, it is determined that the first synchronizer 105 meets the second gear shifting condition.

[0154] In this embodiment, since the first synchronizer 105 is arranged between the ring gear 1041 and the planet carrier 1044, the rotational speed difference between the two ends of the first synchronizer 105 can be obtained in real time by calculating the rotational speed difference between the current rotational speed of the ring gear and the current rotational speed of the planet carrier. Furthermore, when it is detected that the rotational speed difference is less than the rotational speed difference threshold, it indicates that the first synchronizer 105 meets the second gear shifting condition.

[0155] Furthermore, considering that shifting the gear of the first synchronizer 105 when the engine speed decreases may cause the engine 101 to be unable to effectively drive the first motor 103 to generate electricity, the HCU can also determine that the first synchronizer 105 meets the second gear shifting condition when it is detected that the rotational speed difference is less than the rotational speed difference threshold and the current engine speed is greater than or equal to the speed threshold.

[0156] It should be noted that the speed threshold represents the minimum speed at which the engine 101 can drive the first motor 103 to generate electricity stably. In this way, after the vehicle completes the mode switch, the engine 101 can smoothly drive the first motor 103 to generate electricity.

[0157] In this embodiment, by comprehensively considering the rotational speed difference between the two ends of the first synchronizer 105 and the current engine speed of the engine 101, while ensuring the safety of the shift of the first synchronizer 105, it can be ensured that the engine 101 can smoothly drive the first motor 103 to generate electricity after completing the mode switch, thereby effectively avoiding mode switch failure or the vehicle being unable to operate stably in the series mode after completing the mode switch.

[0158] In a feasible embodiment, the step of controlling the first synchronizer 105 to switch from the power split gear to the engaged gear in S203 to enable the vehicle to switch from the power split mode to the series mode may specifically include the following sub-steps:

[0159] S203-1: When the first synchronizer 105 meets the second gear shifting condition, determine the sum of the current motor torque of the first motor 103 and the preset gear engagement assist torque as the target motor torque.

[0160] It should be noted that the current motor torque represents the original motor torque of the first motor 103, that is, the motor torque before torque adjustment of the engine 101.

[0161] In this embodiment, considering that when the first synchronizer 105 switches from the power split gear to the engaged gear, it needs to switch from the gear disengaged state to the locked state. Therefore, by superimposing the gear engagement assist torque on the current motor torque, the target motor torque is obtained, and the first motor 103 is controlled to output the target motor torque, so that the first motor 103 can assist the first synchronizer 105 to successfully complete the gear shifting operation. Among them, the gear engagement assist torque can be set to 2 N·m.

[0162] S203-1: Control the current motor torque of the first motor 103 to follow the target motor torque to assist the first synchronizer 105 to switch from the power split gear to the engaged gear.

[0163] In a specific implementation, the HCU sends a second motor torque adjustment request including the target motor torque to the motor controller, so that the motor controller responds to the second motor torque adjustment request and adjusts the torque of the first motor 103 to make the first motor 103 output the target motor torque.

[0164] In this embodiment, by controlling the first motor 103 to superimpose the gear engagement assist torque, the first synchronizer 105 can, under the auxiliary drive of the first motor 103, improve the gear shifting efficiency while avoiding the phenomenon of gear shifting failure of the first synchronizer 105.

[0165] In a second aspect, based on the same inventive concept, referring to Figure 3 , the embodiment of the present application provides a vehicle mode switching device 300. 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 arranged between the transmission input shaft 107 and the transmission output shaft 108, and the first synchronizer 105 is arranged between the first input end and the output end; the vehicle mode switching device 300 includes:

[0166] A torque adjustment module 301, configured to, when the second synchronizer 106 is in the reverse gear, in response to a mode switching request for switching from the power split mode to the series mode, keep the clutch 102 in the closed state, the first motor 103 in the power generation state, and adjust the torque of the engine 101 to enable the second synchronizer 106 to meet the first gear switching condition;

[0167] The rotational speed adjustment module 302 is configured to control the second synchronizer 106 to shift from the reverse gear to the neutral gear when the second synchronizer 106 meets the first gear shifting condition; and adjust the rotational speed of the first motor 103 to enable the first synchronizer 105 to meet the second gear shifting condition.

[0168] The mode switching module 303 is configured to control the first synchronizer 105 to shift from the power split gear to the engaged gear when the first synchronizer 105 meets the second gear shifting condition, so as to switch the vehicle from the power split mode to the series mode.

[0169] 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 as the first input end, the sun gear 1042 is connected to the first motor as the second input end, the ring gear 1041 is connected to the transmission input shaft 107 as the output end, and the first synchronizer 105 is disposed between the planet carrier 1044 and the ring gear 1041.

[0170] The torque adjustment module 301 includes:

[0171] A gear ratio determination sub-module, configured to determine that the gear ratio between the sun gear 1042 and the planet carrier 1044 is the first gear ratio when the current gear of the first synchronizer 105 is the power split gear.

[0172] An engine torque determination sub-module, configured to determine the target engine torque of the engine 101 based on the current motor torque of the first motor 103 and the first gear ratio.

[0173] An engine torque control sub-module, configured to control the current engine torque of the engine 101 to gradually decrease to the target engine torque based on a preset torque adjustment gradient.

[0174] In an embodiment of the present application, the vehicle mode switching device 300 further includes:

[0175] A compensation torque determination module, configured to determine the compensation torque of the second motor based on the current engine torque and the current motor torque.

[0176] A drive torque determination module, configured to determine the target drive torque of the second motor based on the compensation torque and the current drive torque of the second motor.

[0177] A drive torque control module, configured to control the second motor to gradually increase from the current drive torque to the target drive torque based on the torque adjustment gradient during the process of adjusting the torque of the engine 101.

[0178] In an embodiment of the present application, the vehicle mode switching device 300 further includes:

[0179] A timing module, configured to trigger timing for the duration during which the torque difference between the current engine torque and the target engine torque of the engine 101 is less than a torque threshold.

[0180] A first condition determination module, configured to determine that the second synchronizer 106 meets the first gear shifting condition when the duration is greater than a duration threshold.

[0181] In an embodiment of the present application, the speed regulation module 302 includes:

[0182] A motor speed determination sub-module, configured to determine the target motor speed of the first motor 103 based on the current engine speed of the engine 101 and the first gear ratio.

[0183] A motor speed control sub-module, configured to control the current motor speed of the first motor 103 to follow the target motor speed.

[0184] In an embodiment of the present application, the vehicle mode switching device 300 further includes:

[0185] A ring gear speed determination module, configured to determine the current ring gear speed of the ring gear 1041 based on the current motor speed and the second gear ratio between the ring gear 1041 and the sun gear 1042.

[0186] A carrier speed determination module, configured to determine the current carrier speed of the carrier 1044 based on the current engine speed.

[0187] A second condition determination module, configured to determine that the first synchronizer 105 meets the second gear shifting condition when the speed difference between the current ring gear speed and the current carrier speed is less than a speed difference threshold.

[0188] In an embodiment of the present application, the mode switching module 303 includes:

[0189] A motor torque determination sub-module, configured to determine the target motor torque as the sum of the current motor torque of the first motor 103 and a preset gear engagement assist torque when the first synchronizer 105 meets the second gear shifting condition.

[0190] A gear shifting sub-module, configured to control the current motor torque of the first motor 103 to follow the target motor torque to assist the first synchronizer 105 to switch from the power split gear to the engaged gear.

[0191] It should be noted that for the specific implementation of the vehicle mode switching device 300 in the embodiments of the present application, refer to the specific implementation of the vehicle mode switching method proposed in the first aspect of the embodiments of the present application, which will not be elaborated here.

[0192] In a third aspect, based on the same inventive concept, with reference to Figure 4 , the embodiments of the present application provide a vehicle mode switching system 400. The vehicle includes an engine 101, a clutch 102, a first motor 103, and a transmission; the transmission includes a power splitting 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 splitting mechanism 104 through the clutch 102, the first motor 103 is connected to the second input end of the power splitting mechanism 104, the output end of the power splitting 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, and the first synchronizer 105 is disposed between the first input end and the output end; the system includes a vehicle controller 401, a transmission controller 402, a motor controller 403, and an engine controller 404.

[0193] The vehicle controller 401 is configured to, when the second synchronizer 106 is in the reverse gear, in response to a mode switching request for switching from the power splitting mode to the series mode, send an engine torque adjustment request to the engine controller 404, send a clutch state holding request to the transmission controller 402, and send a motor state holding request to the motor controller 403;

[0194] The transmission controller 402 is configured to, in response to the clutch state holding request, keep the clutch 102 in a closed state; the motor controller 403 is configured to, in response to the motor state holding request, keep the first motor 103 in a power generation state;

[0195] The engine controller 404 is configured to, in response to the engine torque adjustment request, adjust the torque of the engine 101 so that the second synchronizer 106 meets the first gear shifting condition;

[0196] The vehicle controller 401 is further configured to, when the second synchronizer 106 meets the first gear shifting condition, send a first gear shifting request to the transmission controller 402 and send a motor speed adjustment request to the motor controller 403;

[0197] The transmission controller 402 is further configured to, in response to the first gear shifting request, control the second synchronizer 106 to switch from the reverse gear to the neutral gear; the motor controller 403 is further configured to, in response to the motor speed adjustment request, adjust the speed of the first motor 103 so that the first synchronizer 105 meets the second gear shifting condition;

[0198] The vehicle controller 401 is further configured to send a second gear shifting request to the transmission controller 402 when the first synchronizer 105 meets the second gear shifting condition;

[0199] The transmission controller 402 is further configured to, in response to the second gear shifting request, control the first synchronizer 105 to switch from the power split gear to the engaged gear, so that the vehicle switches from the power split mode to the series mode.

[0200] 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.

[0201] Fourthly, based on the same inventive concept, referring to Figure 5 , an embodiment of the present application provides a vehicle 500, including the vehicle mode switching system 400 proposed in the third aspect of the present application.

[0202] 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 present application, which will not be elaborated here.

[0203] Those skilled in the art should understand that the embodiments of the present invention can be provided as a method, a device, or a computer program product. Therefore, the embodiments of the present invention can take the form of an all-hardware embodiment, an all-software embodiment, or an embodiment 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.) containing computer-usable program codes.

[0204] 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 can be implemented by computer program instructions, and the combination of processes and / or blocks in the flowchart and / or block diagram can also be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing terminal devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing terminal devices generate a device for implementing the specified functions in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0205] 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 produce a manufacture including an instruction device that implements the functions specified in one process Figure 1 one process or multiple processes and / or blocks Figure 1 or multiple blocks.

[0206] These computer program instructions can also be loaded onto a computer or other programmable data processing terminal device, such that a series of operational steps are executed on the computer or other programmable terminal device to produce a computer-implemented process, and thus the instructions executed on the computer or other programmable terminal device provide steps for implementing the functions specified in one process Figure 1 one process or multiple processes and / or blocks Figure 1 or multiple blocks.

[0207] 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 learn the basic creative concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications that fall within the scope of the embodiments of the present invention.

[0208] 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 not only includes those elements, but also includes 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 existence of additional identical elements in the process, method, article or terminal device comprising the element.

[0209] 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 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 method includes: When the second synchronizer is in the reverse gear, in response to a mode switching request to switch from the power split mode to the series mode, keep the clutch in the closed state, keep the first motor in the power generation state, and adjust the torque of the engine so that the second synchronizer meets the first gear shifting condition; When the second synchronizer meets the first gear shifting condition, control the second synchronizer to switch from the reverse gear to the neutral gear; and adjust the speed of the first motor so that the first synchronizer meets the second gear shifting condition; When the first synchronizer meets the second gear shifting condition, control the first synchronizer to switch from the power split gear to the engaged gear so that the vehicle switches from the power split mode to the series mode.

2. The vehicle mode switching method according to claim 1, wherein 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; The step of adjusting the torque of the engine includes: When the current gear of the first synchronizer is the power split gear, determine that the transmission ratio between the sun gear and the planet carrier is the first transmission ratio; Based on the current motor torque of the first motor and the first transmission ratio, determine the target engine torque of the engine; Based on a preset torque adjustment gradient, control the current engine torque of the engine to gradually decrease to the target engine torque.

3. The vehicle mode switching method according to claim 2, wherein, The vehicle further includes a second motor, and the method further includes: Based on the current engine torque and the current motor torque, determine the compensation torque of the second motor; Based on the compensation torque and the current driving torque of the second motor, determine the target driving torque of the second motor; During the process of adjusting the torque of the engine, based on the torque adjustment gradient, control the second motor to gradually increase from the current driving torque to the target driving torque.

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

5. The vehicle mode switching method according to claim 2, wherein The step of adjusting the rotational speed of the first motor includes: Based on the current engine speed of the engine and the first gear ratio, determining the target motor speed of the first motor; Controlling the current motor speed of the first motor to follow the target motor speed.

6. The vehicle mode switching method according to claim 5, wherein, The method further includes: Based on the current motor speed and the second gear ratio between the ring gear and the sun gear, determining the current ring gear speed of the ring gear; Based on the current engine speed, determining the current carrier speed of the carrier; When the rotational speed difference between the current ring gear speed and the current carrier speed is less than the rotational speed difference threshold, it is determined that the first synchronizer meets the second gear shifting condition.

7. The vehicle mode switching method according to claim 5, wherein, The step of controlling the first synchronizer to switch from the power split gear to the engaged gear, so that the vehicle switches from the power split mode to the series mode includes: When the first synchronizer meets the second gear shifting condition, determining the sum of the current motor torque of the first motor and a preset shift assist torque as the target motor torque; Controlling the current motor torque of the first motor to follow the target motor torque to assist the first synchronizer to switch from the power split gear to the engaged gear.

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, when the second synchronizer is in the reverse gear, in response to a mode switching request to switch from the power split mode to the series mode, keep the clutch in a closed state, keep the first motor in a power generation state, and adjust the torque of the engine so that the second synchronizer meets the first gear shifting condition; A rotational speed adjustment module, configured to, when the second synchronizer meets the first gear shifting condition, control the second synchronizer to switch from the reverse gear to the neutral gear; and adjust the rotational speed of the first motor so that the first synchronizer meets the second gear shifting condition; A mode switching module, configured to, when the first synchronizer meets the second gear shifting condition, control the first synchronizer to switch from the power split gear to the engaged gear, so that the vehicle switches from the power split mode to the series 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 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 system includes a vehicle controller, a transmission controller, a motor controller, and an engine controller; wherein, The vehicle controller is configured to, when the second synchronizer is in the reverse gear, in response to a mode switching request for switching from a power split mode to a series mode, send an engine torque adjustment request to the engine controller, send a clutch state holding request to the transmission controller, and send a motor state holding request to the motor controller; The transmission controller is configured to, in response to the clutch state holding request, keep the clutch in a closed state; the motor controller is configured to, in response to the motor state holding request, keep the first motor in a power generation state; The engine controller is configured to, in response to the engine torque adjustment request, adjust the torque of the engine so that the second synchronizer meets the first gear shifting condition; The vehicle controller is further configured to, when the second synchronizer meets the first gear shifting condition, send a first gear shifting request to the transmission controller and send a motor speed adjustment request to the motor controller; The transmission controller is further configured to, in response to the first gear shifting request, control the second synchronizer to switch from the reverse gear to the neutral gear; the motor controller is further configured to, in response to the motor speed adjustment request, adjust the speed of the first motor so that the first synchronizer meets the second gear shifting condition; The vehicle controller is further configured to, when the first synchronizer meets the second gear shifting condition, send a second gear shifting request to the transmission controller; The transmission controller is further configured to, in response to the second gear shifting request, control the first synchronizer to switch from the power split gear to the engaged gear, so that the vehicle switches from the power split mode to the series mode.

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

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