Vehicle mode switching method and system and vehicle

Abstract

The invention provides a vehicle mode switching method and system and a vehicle, and belongs to the technical field of vehicle control. According to the embodiment of the invention, when it is determined that a driver has the reversing intention, whether the vehicle meets the mode switching condition of switching from a series connection mode to a power dividing mode or not can be accurately judged by recognizing the working condition information of the vehicle; therefore, when the vehicle meets the mode switching condition, the clutch can be kept in the closed state, the first motor can be kept in the power generation state, torque adjustment is conducted on the engine, then the rotating speed of the first motor is adjusted, and in the vehicle mode switching process, the clutch can be switched on and off on the premise that power generation of the first motor is kept. In this way, in the mode switching process, the engine can continuously drive the first motor to charge the power battery, the mode switching time can be effectively shortened, the power response performance of the vehicle is improved, and then rapid reversing is achieved.

Description

Technical Field

[0001] The present application relates to the technical field of vehicle control, and in particular, to a vehicle mode switching method, 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, during the process of a vehicle switching from the series mode in the straight - driving state to the power split mode in the reverse state, the vehicle usually needs to first open the clutch, then perform torque reduction and speed regulation operations on the engine and the motor, 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 not only causes the engine to be unable to drive the motor to charge the power battery after the clutch is opened, but also results in a long mode switching time and untimely engine power response, thereby affecting the power response performance of the vehicle during mode switching. Summary of the Invention

[0004] The present application provides a vehicle mode switching method, 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 a hybrid vehicle switches from the series mode to the power split 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 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:

[0007] When it is determined that the driver has a reverse intention, based on the working condition information of the vehicle, determine whether the vehicle meets the mode switching condition for switching from the series mode to the power split mode;

[0008] When it is determined that the vehicle meets the mode switching condition, 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 first synchronizer meets the first gear shifting condition;

[0009] 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 speed of the first motor so that the second synchronizer meets the second gear shifting condition;

[0010] When the second synchronizer meets the second gear shifting condition, control the second synchronizer to shift from the current gear to the reverse gear so that the vehicle switches from the series mode to the power split mode.

[0011] In an embodiment of the present application, the operating condition information includes the current driving mode, the current road condition, and the current remaining power of the power battery;

[0012] The step of determining whether the vehicle meets the mode switching condition for switching from the series mode to the power split mode based on the operating condition information of the vehicle includes:

[0013] When the current driving mode is the series mode, the current road condition is a preset road condition, and the current remaining power is less than the power threshold, it is determined that the vehicle meets the mode switching condition for switching from the series mode to the power split mode.

[0014] 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;

[0015] The step of adjusting the torque of the engine includes:

[0016] When the current gear of the first synchronizer is the engaged gear, determine that the speed ratio between the sun gear and the planet carrier is the first speed ratio;

[0017] Based on the original motor torque of the first motor and the first speed ratio, determine the target engine torque of the engine;

[0018] Based on a preset torque adjustment gradient, control the engine to gradually decrease from the original engine torque to the target engine torque.

[0019] In one embodiment of the present application, the vehicle further includes a second motor, and the method further includes:

[0020] Determine a compensation torque of the second motor based on the original engine torque and the original motor torque;

[0021] Determine a target drive torque of the second motor based on the compensation torque and the original drive torque of the second motor;

[0022] During the process of adjusting the torque of the engine, control the second motor to gradually increase from the original drive torque to the target drive torque based on the torque adjustment gradient.

[0023] In one embodiment of the present application, the method further includes:

[0024] 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 a first duration during which the torque difference is less than the torque threshold;

[0025] When the first duration is greater than a first duration threshold, determine that the first synchronizer meets the first gear shifting condition.

[0026] In one embodiment of the present application, the step of adjusting the speed of the first motor includes:

[0027] Determine a target motor speed of the first motor based on the current wheel speed of the target wheel, the current gear position of the first synchronizer, and the target gear position of the second synchronizer;

[0028] Control the current motor speed of the first motor to follow the target motor speed.

[0029] In one embodiment of the present application, the step of determining the target motor speed of the first motor based on the current wheel speed of the target wheel, the current gear position of the first synchronizer, and the target gear position of the second synchronizer includes:

[0030] When the current gear position of the first synchronizer is the power split gear position, determine that the speed ratio between the sun gear and the ring gear is a second speed ratio;

[0031] When the target gear position of the second synchronizer is the reverse gear position, determine that the speed ratio between the transmission input shaft and the target wheel is a third speed ratio;

[0032] Determine a fourth speed ratio between the target wheel and the first motor based on the second speed ratio and the third speed ratio;

[0033] Based on the fourth gear ratio and the current wheel speed of the target wheel, determine the target motor speed of the first motor.

[0034] In an embodiment of the present application, the method further includes:

[0035] When the current motor speed of the first motor reaches the target motor speed, trigger the timing of the second duration during which the fluctuation amplitude of the current motor speed is less than the speed threshold;

[0036] When the second duration is greater than the second duration threshold, determine that the second synchronizer meets the second gear shifting condition.

[0037] In a 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, and the first synchronizer is arranged between the first input end and the output end; the device includes:

[0038] A condition determination module, configured to, when it is determined that the driver has a reverse intention, determine whether the vehicle meets the mode switching condition for switching from the series mode to the power split mode based on the working condition information of the vehicle;

[0039] A torque adjustment module, configured to, when it is determined that the vehicle meets the mode switching condition, keep the clutch in a closed state, keep the first motor in a power generation state, and perform torque adjustment on the engine so that the first synchronizer meets the first gear shifting condition;

[0040] A speed adjustment module, configured to, when the first synchronizer meets the first gear shifting condition, control the first synchronizer to switch from the engaged gear to the power split gear; and perform speed adjustment on the first motor so that the second synchronizer meets the second gear shifting condition;

[0041] A mode switching module, configured to, when the second synchronizer meets the second gear shifting condition, control the second synchronizer to switch from the current gear to the reverse gear so that the vehicle switches from the series mode to the power split mode.

[0042] In one embodiment of the present application, the operating condition information includes the current driving mode, the current road condition, and the current remaining power of the power battery; the condition determination module includes:

[0043] A switching condition determination sub-module, configured to determine that the vehicle meets the mode switching condition for switching from the series mode to the power split mode when the current driving mode is the series mode, the current road condition is a preset road condition, and the current remaining power is less than the power threshold.

[0044] In one 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; the torque adjustment module includes:

[0045] A gear ratio determination sub-module, configured to determine that the gear ratio between the sun gear and the planet carrier is a first gear ratio when the current gear position of the first synchronizer is the engaged gear position;

[0046] An engine torque determination sub-module, configured to determine the target engine torque of the engine based on the original motor torque of the first motor and the first gear ratio;

[0047] An engine torque control sub-module, configured to control the engine to gradually decrease from the original engine torque to the target engine torque based on a preset torque adjustment gradient.

[0048] In one embodiment of the present application, the vehicle mode switching device further includes:

[0049] A compensation torque determination module, configured to determine the compensation torque of the second motor based on the original engine torque and the original motor torque;

[0050] A driving torque determination module, configured to determine the target driving torque of the second motor based on the compensation torque and the original driving torque of the second motor;

[0051] A driving torque control module, configured to control the second motor to gradually increase from the original driving torque to the target driving torque based on the torque adjustment gradient during the process of adjusting the torque of the engine.

[0052] In one embodiment of the present application, the vehicle mode switching device further includes:

[0053] The first timing module is used to trigger timing for a first 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.

[0054] The first condition determination module is used to determine that the first synchronizer meets the first gear shifting condition when the first duration is greater than a first duration threshold.

[0055] In an embodiment of the present application, the rotational speed adjustment module includes:

[0056] The motor rotational speed determination sub-module is used to determine the target motor rotational speed of the first motor based on the current wheel rotational speed of the target wheel, the current gear position of the first synchronizer, and the target gear position of the second synchronizer.

[0057] The motor rotational speed control sub-module is used to control the current motor rotational speed of the first motor to follow the target motor rotational speed.

[0058] In an embodiment of the present application, the motor rotational speed determination sub-module includes:

[0059] The first speed ratio determination unit is used to determine that the speed ratio between the sun gear and the ring gear is a second speed ratio when the current gear position of the first synchronizer is the power split gear position.

[0060] The second speed ratio determination unit is used to determine that the speed ratio between the transmission input shaft and the target wheel is a third speed ratio when the target gear position of the second synchronizer is the reverse gear position.

[0061] The third speed ratio determination unit is used to determine a fourth speed ratio between the target wheel and the first motor based on the second speed ratio and the third speed ratio.

[0062] The target motor rotational speed determination unit is used 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.

[0063] In an embodiment of the present application, the vehicle mode switching device further includes:

[0064] The second timing module is used to trigger timing for a second duration during which the 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.

[0065] The second condition determination module is used to determine that the second synchronizer meets the second gear shifting condition when the second duration is greater than a second duration threshold.

[0066] 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 splitting 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 splitting mechanism through the clutch. The first motor is connected to a second input end of the power splitting mechanism. An output end of the power splitting 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,

[0067] the vehicle controller is configured to, when determining that the driver has a reverse intention, determine whether the vehicle meets the mode switching condition for switching from the series mode to the power splitting mode based on the operating condition information of the vehicle. And when determining that the vehicle meets the mode switching condition, 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;

[0068] the transmission controller is configured to keep the clutch in a closed state in response to the clutch state holding request; the motor controller is configured to keep the first motor in a power generation state in response to the motor state holding request;

[0069] the engine controller is configured to adjust the torque of the engine in response to the engine torque adjustment request so that the first synchronizer meets the first gear shifting condition;

[0070] the vehicle controller is further configured to, when the first 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;

[0071] the transmission controller is further configured to control the first synchronizer to switch from the engaged gear to the power splitting gear in response to the first gear shifting request. The motor controller is further configured to adjust the speed of the first motor in response to the motor speed adjustment request so that the second synchronizer meets the second gear shifting condition;

[0072] the vehicle controller is further configured to, when the second synchronizer meets the second gear shifting condition, send a second gear shifting request to the transmission controller;

[0073] The transmission controller is further configured to control the second synchronizer to switch from the current gear to the reverse gear in response to the second gearshift request, so that the vehicle switches from the series mode to the power split mode.

[0074] 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.

[0075] Compared with the prior art, the present application has the following advantages:

[0076] A vehicle mode switching method provided by an embodiment of the present application, by determining that the driver has a reverse intention, based on the vehicle condition information, determines whether the vehicle meets the mode switching condition for switching from the series mode to the power split mode. When it is determined that the vehicle meets the mode switching condition, the clutch can be kept in the closed state, the first motor is in the power generation state, and the torque of the engine is adjusted, so that when the first synchronizer meets the first gear switching condition, the first synchronizer can be controlled to switch from the engaged gear to the power split gear; and by adjusting the speed of the first motor, when the second synchronizer meets the second gear switching condition, the second synchronizer can be controlled to switch from the current gear to the reverse gear, so that the vehicle switches from the series mode to the power split mode. By identifying the vehicle condition information when the driver has a reverse intention, the embodiment of the present application can control the vehicle to automatically switch from the series mode to the power split mode. At the same time, 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 first synchronizer and the second synchronizer can be completed in sequence without 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 series mode to the power split mode in the reverse state more quickly and smoothly. While meeting the charging requirements of the power battery, the mode switching duration is effectively shortened, so that the engine can quickly output torque to achieve a quick reverse, and thus effectively improve the power response performance of the vehicle during the mode switching process. Description of the Drawings

[0077] In order 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 following drawings 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.

[0078] Figure 1 It is a schematic structural diagram of a hybrid vehicle in an embodiment of the present application.

[0079] Figure 2 It is a flowchart of the steps of a vehicle mode switching method in an embodiment of the present application.

[0080] Figure 3 It is a schematic diagram of the functional modules of a vehicle mode switching device in an embodiment of the present application.

[0081] Figure 4 It is a schematic structural diagram of a vehicle mode switching system in an embodiment of the present application.

[0082] Figure 5 It is a schematic structural diagram of a vehicle in an embodiment of the present application. Detailed implementation manners

[0083] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0084] Referring to Figure 1 , a schematic structural diagram of a hybrid vehicle in an embodiment of the present application is shown. An engine 101, a clutch 102, a first motor 103 and a gearbox are provided 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.

[0085] The second synchronizer 106 is disposed between the gearbox input shaft 107 and the gearbox output shaft 108 and is used to couple or disconnect the gearbox input shaft 107 and the gearbox output shaft 108. Specifically, when the second synchronizer 106 is in gear, the second synchronizer 106 is used to couple the gearbox input shaft 107 and the gearbox output shaft 108; when the second synchronizer 106 is in neutral, the second synchronizer 106 is used to disconnect the gearbox input shaft 107 and the gearbox output shaft 108.

[0086] The first synchronizer 105 is disposed between the first input end and the output end and is configured to couple or disconnect the first input end and the output end. Specifically, when the first synchronizer 105 is in the coupled 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 coupled gear position, the vehicle can be in other modes outside the power split mode, for example, the series mode, the direct drive mode, or the pure electric four-wheel drive mode, etc.

[0087] Further, the transmission output shaft 108 is also connected to the front axle wheels through the front axle differential 109 and is configured 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 further provided with a second motor (not shown in the figure) at the rear axle of the vehicle, and the second motor is configured 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.

[0088] 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 be provided with 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:

[0089] 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 the other part of the output power is used to directly drive the vehicle to travel.

[0090] 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.

[0091] Specifically, when the vehicle is reversing in the power split mode, the second synchronizer 106 is in the R gear (reverse gear). At this time, the R gear rotates in the reverse direction to realize vehicle reversing; when the vehicle is going straight in the series mode, the second synchronizer 106 is in the D gear (forward gear), such as D1 (first gear), D2 (second gear) or D3 (third gear).

[0092] In the related art, according to changes in road conditions and driving requirements, a hybrid vehicle may need to switch from a series mode in a straight-ahead state to a power-split mode in a reverse state. In traditional vehicle mode switching strategies, the vehicle needs to first disengage the clutch 104, and then perform torque reduction and speed regulation operations on the engine 101 and the first motor 103. After the torque reduction and speed regulation operations are completed, the clutch 104 is re-engaged to complete the mode switch. 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 longer mode switch time and untimely power response of the engine 101 will occur, thereby affecting the power response performance of the vehicle during the mode switch.

[0093] Aiming at 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 series mode to the power-split mode in the reverse state. The present application aims to provide a vehicle mode switching method, system and vehicle, which can keep the clutch 102 in a closed state, the first motor 103 in a power generation state, and by adjusting the torque of the engine 101 and then adjusting the speed of the first motor 103, so that during the vehicle mode switch, the shifting operations of the second synchronizer 106 and the first synchronizer 105 can be completed in sequence without opening the clutch 102. 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 more quickly and smoothly from the power-split mode to the series mode in the reverse state. While meeting the charging requirements of the power battery, the mode switch duration is effectively shortened, enabling the engine 101 to quickly output torque and improving the power response performance of the vehicle during the mode switch.

[0094] Referring to Figure 2 , a vehicle mode switching method of the present application is shown, which is applied to a hybrid vehicle adopting the above architecture. The method may include the following steps:

[0095] S201: When it is determined that the driver has a reverse intention, based on the vehicle condition information, determine whether the vehicle meets the mode switch condition for switching from the series mode to the power-split mode.

[0096] It should be noted that the execution subject 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 or an in-vehicle computer, such as an ECU (Electronic Control Unit), a BCM (Body Control Module), an HCU (Hybrid Control Unit), etc. This embodiment will take the HCU as the execution subject for description. It should be noted that this embodiment does not make specific restrictions on the execution subject of the vehicle.

[0097] In this embodiment, the HCU can detect the position of the vehicle gear lever to determine whether the driver has a reverse intention. For example, when it is detected that the gear lever position switches from the current position to the reverse gear position, it is determined that the driver has a reverse intention. Among them, the current position can be the neutral position or the parking gear position.

[0098] Furthermore, after determining that the driver has a reverse intention, the HCU will obtain the vehicle operating condition information, and then based on the operating condition information, determine whether the vehicle needs to switch from the series mode to the power split mode in the reverse state.

[0099] In a specific implementation, the operating condition information may include the current driving mode, the current road condition, and the current SOC (State of Charge) of the power battery. The HCU determines that the vehicle meets the mode switching condition for switching from the series mode to the power split mode when the current driving mode is the series mode, the current road condition is a preset road condition, and the current remaining power is less than the power threshold. Among them, the current road condition can be identified based on the perception result of the road surface by the perception system and the driving state information including the current vehicle speed and the current acceleration.

[0100] It should be noted that the preset road condition represents a road condition that requires the vehicle to be in the four-wheel drive mode, such as a desert road condition, a muddy road condition, and a snowy road condition, etc.; the power threshold represents the charging balance point of the power battery. For example, it can be set to 20%. That is, when the current SOC of the power battery is less than 20%, it means that before the mode switch, that is, in the series mode, the remaining power of the power battery has not been charged above the charging balance point. Therefore, after the vehicle enters the reverse state, it still needs to meet the charging demand of the power battery, that is, control the vehicle to enter the power split mode in the reverse state.

[0101] In this embodiment, by analyzing the operating condition information when the driver has a reverse intention, the vehicle can be controlled to automatically switch from the series mode to the power split mode, thereby effectively meeting the driver's driving needs under the preset road condition while meeting the charging demand of the power battery.

[0102] S202: When it is determined that the vehicle meets the mode switching condition, keep the clutch 102 in the closed state, keep the first motor in the power generation state, and adjust the torque of the engine 101 so that the first synchronizer 105 meets the first gear switching condition.

[0103] In this embodiment, after the HCU determines that the vehicle meets the mode switching condition, it will 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, it will 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, it will 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.

[0104] It should be noted that in the series mode, the first synchronizer 105 is in 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 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 to the power split gear. 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 as needed, such as 2:1. To avoid damage to the first synchronizer 105, when the first synchronizer 105 is shifted out of gear, the torque applied to the first synchronizer 105 is required to be a small value, and ideally it is zero.

[0105] 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 engine torque of the engine 101, the torque applied by the engine 101 to the power split mechanism 104 can be used to offset the torque applied by the first motor to the power split mechanism 104, and then the torque of the power split mechanism 104 acting on the first synchronizer 105 can be adjusted. In this way, without opening the clutch 102 and without reducing the torque of the first motor, the torque at the first synchronizer 105 can be balanced to the torque required for shifting out of gear, so that the first synchronizer 105 meets the first gear switching condition.

[0106] S203: When the first synchronizer 105 meets the first gear switching condition, control the first synchronizer 105 to switch from the engaged gear to the power split gear; and adjust the speed of the first motor so that the second synchronizer 106 meets the second gear switching condition.

[0107] 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 request indicating that the target gear is the power split gear to the transmission controller, so that the transmission controller, in response to the first gear request, controls the first synchronizer 105 to disengage to the power split gear.

[0108] 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 motor speed regulation request including the target motor speed to the motor controller, so that the motor controller, in response to the motor speed regulation request, based on the target motor speed, adjusts the current motor speed of the first motor 103 to make the second synchronizer 106 meet the second gear shifting condition.

[0109] 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 transmission ratio between the transmission input shaft 107 and the transmission output shaft 108. Before the second synchronizer 106 is shifted from the current gear to the reverse gear, the speed difference between both ends of the second synchronizer 106 needs to be adjusted to a small value, ideally zero. Since the vehicle also needs to pass through the neutral gear when switching from the forward gear to the reverse gear, the current gear can specifically be set to the neutral gear.

[0110] In this embodiment, considering that the first motor 103 is connected to the power split mechanism 104 and the torque balance of the first motor has been achieved by using the engine 101, 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 disengaging the clutch 102 and while maintaining the power generation of the first motor, so that the second synchronizer 106 meets the second gear shifting condition.

[0111] S204: When the second synchronizer 106 meets the second gear shifting condition, control the second synchronizer 106 to switch from the current gear to the reverse gear, so that the vehicle switches from the series mode to the power split mode.

[0112] In this embodiment, after the HCU detects that the second synchronizer 106 meets the second gear shifting condition, it will send a second gear request including the target gear as the reverse gear to the transmission controller, so that the transmission controller, in response to the second gear request, controls the second synchronizer 106 to switch from the current gear to the reverse gear.

[0113] 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 to drive the vehicle to reverse.

[0114] 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.

[0115] It should be noted that the absolute value of the first torque is greater than 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.

[0116] A vehicle mode switching method provided by an embodiment of the present application can control the vehicle to automatically switch from the series mode to the power split mode by identifying the working condition information of the vehicle when the driver has a reverse intention; at the same time, only the torque of the engine 101 needs to be adjusted, and then the speed of the first motor is adjusted. Then, during the vehicle mode switching process, without opening the clutch 102 and keeping the first motor generating electricity, the shifting operations of the first synchronizer 105 and the second synchronizer 106 can be completed in sequence. In this way, the engine 101 can not only continuously drive the first motor to charge the power battery, but also enable the vehicle to switch from the series mode to the power split mode in the reverse state more quickly and smoothly. 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 to achieve a quick reverse, and thus effectively improve the dynamic response performance of the vehicle during the mode switching process.

[0117] In a feasible embodiment, continue to refer to Figure 1, the power splitting 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 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.

[0118] In the series mode, the first synchronizer 105 is in the engaged gear position and the second synchronizer 106 is in the neutral 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 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.

[0119] 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 disconnected 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.

[0120] Based on the above structure, the step of adjusting the torque of the engine 101 in S202 may specifically include the following sub-steps:

[0121] S202-1: When the current gear position of the first synchronizer 105 is the engaged gear position, determine that the transmission ratio between the sun gear 1042 and the planet carrier 1044 is the first transmission ratio.

[0122] 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 gears, 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 101, therefore, based on the current gear of the first synchronizer 105, the speed ratio between the first motor 103 and the engine 101 can be determined.

[0123] In this embodiment, since the current gear of the first synchronizer 105 is the engaged gear 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.

[0124] S202-2: Based on the original motor torque of the first motor and the first speed ratio, determine the target engine torque of the engine 101.

[0125] In this embodiment, since speed and torque are inversely proportional, therefore, 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.

[0126] S202-3: Based on the preset torque adjustment gradient, control the engine 101 to gradually decrease from the original engine torque to the target engine torque.

[0127] 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.

[0128] In a specific implementation, the current engine torque of the engine 101 can be controlled to follow the target engine torque according to the 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.

[0129] 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.

[0130] In a feasible embodiment, the vehicle further includes a second motor, and the vehicle mode switching method may further include the following steps:

[0131] S301: Based on the original engine torque and the original motor torque, determine the compensation torque of the second motor.

[0132] In this embodiment, considering that during the process of adjusting the torque of the engine 101, the torque for driving the front axle wheels will continuously decrease. To ensure the power demand of the whole vehicle during mode switching, torque compensation will be performed by the second motor.

[0133] In this embodiment, since the original motor torque is a negative torque and is used to offset a part of the positive torque of the original engine torque, the HCU can determine the sum of the original engine torque and the original motor torque as the compensation torque of the second motor.

[0134] It should be noted that the original engine torque represents the engine torque before torque adjustment of the engine 101; the original motor torque represents the motor torque before torque adjustment of the engine 101.

[0135] Exemplarily, before torque adjustment of the engine 101, if the original engine torque is 800 N·m and the original motor torque is -300 N·m, the compensation torque of the second motor is 500 N·m.

[0136] S302: Determine the target drive torque of the second motor based on the compensation torque and the original drive torque of the second motor.

[0137] In this embodiment, the HCU will further superimpose the compensation torque on the basis of the original 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.

[0138] It should be noted that the original drive torque represents the torque output by the second motor before torque adjustment of the engine 101.

[0139] S303: During the process of torque adjustment of the engine 101, control the second motor to gradually increase from the original drive torque to the target drive torque based on the torque adjustment gradient.

[0140] In this embodiment, during the process of torque adjustment of 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.

[0141] In an example, the torque adjustment gradient is set to 200 N·m / s. If the HCU detects that the original engine torque output by the engine 101 is 800 N·m, the original motor torque output by the first motor 103 is -300 N·m, and the original drive torque output by the second motor is 400 N·m, it will respond to the mode switching request and 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.

[0142] 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, effectively meeting the driver's power demand during the mode switching process, and at the same time avoiding abnormal jerks and other phenomena of the vehicle.

[0143] In a feasible embodiment, the vehicle mode switching method may further include the following steps:

[0144] 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 for the first duration during which the torque difference is less than the torque threshold.

[0145] In this embodiment, during the process of the HCU adjusting the torque of the engine 101, the current engine torque feedback by the engine controller in real time will be obtained. Then, when it is detected that the torque difference between the current engine torque and the target engine torque is less than the torque threshold, the timer will accumulate and time for the first duration. Then, based on the first duration, it is determined whether the engine 101 is stably operating at the target engine torque. Among them, the first duration represents the duration of the engine 101 continuously and stably operating in the torque dimension, which can be specifically set to 50 ms.

[0146] S402: When the first duration is greater than the first duration threshold, determine that the second synchronizer 106 meets the first gear shifting condition.

[0147] In this embodiment, if the HCU detects that the first duration is greater than the first duration threshold, it is considered that the engine 101 is stably operating at the target engine torque, and then it is determined that the second synchronizer 106 meets the first gear shifting condition.

[0148] In this embodiment, by monitoring the first duration, it can effectively avoid controlling the second synchronizer 106 to perform gear shifting operations in the case of abnormal torque fluctuations of the engine 101, and then ensure that the second synchronizer 106 can shift gears smoothly.

[0149] In a feasible embodiment, the step of adjusting the speed of the first motor 103 in S203 may specifically include the following sub-steps:

[0150] S203-1: Based on the current wheel speed of the target wheel, the current gear of the first synchronizer 105, and the target gear of the second synchronizer 106, determine the target motor speed of the first motor.

[0151] In this embodiment, since a first synchronizer 105 and a second synchronizer 106 are 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, in order to accurately calculate the target motor speed of the first motor 103 and ensure that the second synchronizer 106 can be smoothly engaged into the target gear, the HCU will determine the target motor speed of the first motor 103 based on the current wheel speed of the target wheel and the current gear of the first synchronizer 105 and the target gear of the second synchronizer 106.

[0152] 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 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.

[0153] In specific implementation, S203-1 may specifically include the following sub-steps:

[0154] S203-1-1: When the current gear of the first synchronizer 105 is the power split gear, determine that the gear ratio between the sun gear 1042 and the ring gear 1041 is the second gear ratio.

[0155] It should be noted that when the current gear of the first synchronizer 105 is the power split gear, the planetary carrier 1044 and the ring gear 1041 are in the gear disengaged state. At this time, the speed decoupling between the engine 101 and the transmission input shaft 107 is achieved. Therefore, the speed of the transmission input shaft 107 can be adjusted by the first motor while keeping the speed of the engine 101 unchanged, so that the second synchronizer 106 meets the second gear shifting condition.

[0156] It should be noted that different gears of the first synchronizer 105 correspond to different gear ratios. Specifically, when the current gear of the first synchronizer 105 is the power split gear, the gear ratio between the sun gear 1042 and the ring gear 1041 is the second gear ratio.

[0157] S203-1-2: When the target gear of the second synchronizer 106 is the reverse gear, determine that the gear ratio between the transmission input shaft 107 and the target wheel is the third gear ratio.

[0158] In this embodiment, different gear positions of the second synchronizer 106 correspond to different gear ratios. When the target gear position of the second synchronizer 106 is the reverse gear, the gear ratio between the transmission input shaft 107 and the target wheel is the target gear ratio. This target gear ratio represents the gear ratio between the transmission input shaft 107 and the transmission output shaft 108. Therefore, based on the target gear ratio and in combination with 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.

[0159] S203-1-3: Determine the fourth gear ratio between the target wheel and the first motor based on the second gear ratio and the third gear ratio.

[0160] In this embodiment, based on the second gear ratio, the gear ratio between the sun gear 1042 and the ring gear 1041 can be calculated. Since the rotational speeds of the first motor 103 and the sun gear 1042 are the same, and the rotational speeds of the ring gear 1041 and the transmission input shaft 107 are the same, therefore, by further combining the third gear ratio, the fourth gear ratio between the first motor 103 and the target wheel can be calculated.

[0161] In specific implementation, the fourth gear ratio between the first motor 103 and the target wheel can be calculated according to the following formula:

[0162] i3 = i1 × i2 (1);

[0163] Wherein, i3 represents the fourth gear ratio between the first motor 103 and the target wheel, i1 represents the second gear ratio between the sun gear 1042 and the ring gear 1041, and i2 represents the third gear ratio between the transmission input shaft 107 and the target wheel.

[0164] S203-1-4: Determine the target motor speed of the first motor based on the fourth gear ratio and the current wheel speed of the target wheel.

[0165] In specific implementation, the target motor speed of the first motor 103 can be calculated according to the following formula:

[0166] n = n0 × i3 (2);

[0167] Wherein, n represents the target motor speed of the first motor 103, n0 represents the current wheel speed of the target wheel, and i3 is the fourth gear ratio between the first motor 103 and the target wheel.

[0168] S203-2: Control the current motor speed of the first motor to follow the target motor speed.

[0169] In this embodiment, while sending a speed control request to the motor controller, the HCU also sends 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, thereby achieving precise control of the motor speed.

[0170] In this embodiment, after receiving the speed control request and switching to the speed control mode, the motor controller will activate the PI (proportional-integral) speed loop for the first motor 103, and control the current motor speed of the first motor 103 to follow the target motor speed in a closed-loop control manner.

[0171] 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 first calculates the first speed difference between the target motor speed and the current motor speed, and then inputs 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.

[0172] 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 the 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.

[0173] 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.

[0174] In a feasible embodiment, the vehicle mode switching method may further include the following steps:

[0175] S501: When the current motor speed of the first motor reaches the target motor speed, trigger the timing of the second duration during which the fluctuation amplitude of the current motor speed is less than the speed threshold.

[0176] In this embodiment, considering that the first motor 103 may have speed fluctuations during the speed regulation process, in order to ensure the smooth 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.

[0177] In a specific implementation, after the HCU first detects that the current motor speed reaches the target motor speed, it will trigger the timing of the second duration. The second duration represents the duration during which the first motor 103 continuously operates stably in terms of speed, and can be specifically set to 50 ms.

[0178] S502: When the second duration is greater than the second duration threshold, it is determined that the second synchronizer 106 meets the second gear shifting condition.

[0179] In this embodiment, when the second duration is greater than the second duration threshold, it means that the current motor speed of the first motor 103 fluctuates near the target motor speed with a fluctuation amplitude less than the speed threshold, that is, it is in a stable operating state.

[0180] In this embodiment, by monitoring the current motor speed during the process of regulating the speed of the first motor 103, it is possible to accurately determine whether the second synchronizer 106 meets the second gear shifting condition, thereby ensuring that the second synchronizer 106 can shift gears smoothly and effectively avoiding situations such as damage to the second synchronizer 106 and shifting failure.

[0181] Second, 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, 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:

[0182] A condition determination module 301, configured to determine whether the vehicle meets the mode switching condition for switching from the series mode to the power split mode based on the vehicle's operating condition information when it is determined that the driver has a reverse intention.

[0183] The torque adjustment module 302 is configured to keep the clutch 102 in a closed state and the first motor in a power generation state when it is determined that the vehicle meets the mode switching condition, and adjust the torque of the engine 101 so that the first synchronizer 105 meets the first gear switching condition;

[0184] The speed adjustment module 303 is configured to control the first synchronizer 105 to switch from the engaged gear to the power split gear when the first synchronizer 105 meets the first gear switching condition; and adjust the speed of the first motor so that the second synchronizer 106 meets the second gear switching condition;

[0185] The mode switching module 304 is configured to control the second synchronizer 106 to switch from the current gear to the reverse gear when the second synchronizer 106 meets the second gear switching condition, so that the vehicle switches from the series mode to the power split mode.

[0186] In an embodiment of the present application, the working condition information includes the current driving mode, the current road condition, and the current remaining power of the power battery; the condition determination module 301 includes:

[0187] The switching condition determination sub-module is configured to determine that the vehicle meets the mode switching condition for switching from the series mode to the power split mode when the current driving mode is the series mode, the current road condition is the preset road condition, and the current remaining power is less than the power threshold.

[0188] 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 arranged between the planet carrier 1044 and the ring gear 1041; the torque adjustment module 302 includes:

[0189] The gear ratio determination sub-module is 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 engaged gear;

[0190] The engine torque determination sub-module is configured to determine the target engine torque of the engine 101 based on the original motor torque of the first motor and the first gear ratio;

[0191] The engine torque control sub-module is configured to control the engine 101 to gradually decrease from the original engine torque to the target engine torque based on the preset torque adjustment gradient.

[0192] In an embodiment of the present application, the vehicle mode switching device 300 further includes:

[0193] A compensation torque determination module, which determines the compensation torque of the second motor based on the original engine torque and the original motor torque;

[0194] A driving torque determination module, which is used to determine the target driving torque of the second motor based on the compensation torque and the original driving torque of the second motor;

[0195] A driving torque control module, which is used to control the second motor to gradually increase from the original driving torque to the target driving torque based on the torque adjustment gradient during the process of adjusting the torque of the engine 101.

[0196] In an embodiment of the present application, the vehicle mode switching device 300 further includes:

[0197] A timing module, which is used to trigger timing for a first duration when the torque difference between the current engine torque and the target engine torque of the engine 101 is less than the torque threshold;

[0198] A first condition determination module, which is used to determine that the first synchronizer 105 meets the first gear shifting condition when the first duration is greater than the first duration threshold.

[0199] In an embodiment of the present application, the speed regulation module 303 includes:

[0200] A motor speed determination sub-module, which is used to determine the target motor speed of the first motor based on the current wheel speed of the target wheel, the current gear position of the first synchronizer 105, and the target gear position of the second synchronizer 106;

[0201] A motor speed control sub-module, which is used to control the current motor speed of the first motor to follow the target motor speed.

[0202] In an embodiment of the present application, the motor speed determination sub-module includes:

[0203] A first gear ratio determination unit, which is used to determine that the gear ratio between the sun gear 1042 and the ring gear 1041 is the second gear ratio when the current gear position of the first synchronizer 105 is the power split gear position;

[0204] A second gear ratio determination unit, which is used to determine that the gear ratio between the transmission input shaft 107 and the target wheel is the third gear ratio when the target gear position of the second synchronizer 106 is the reverse gear;

[0205] A third gear ratio determination unit, which is used to determine the fourth gear ratio between the target wheel and the first motor based on the second gear ratio and the third gear ratio;

[0206] A target motor speed determination unit, configured to determine a target motor speed of the first motor based on a fourth gear ratio and a current wheel speed of a target wheel.

[0207] In an embodiment of the present application, the vehicle mode switching device further includes:

[0208] A second timing module, configured to trigger timing of a second duration during which a fluctuation amplitude of the current motor speed is less than a speed threshold when the current motor speed of the first motor reaches the target motor speed;

[0209] A second condition determination module, configured to determine that the second synchronizer 106 satisfies a second gear shifting condition when the second duration is greater than a second duration threshold.

[0210] It should be noted that for the specific implementation manner of the vehicle mode switching device 300 in the embodiment of the present application, refer to the specific implementation manner of the vehicle mode switching method proposed in the first aspect of the embodiment of the present application, which will not be elaborated here.

[0211] In a third aspect, based on the same inventive concept, refer to Figure 4 , the embodiment of the present application provides a vehicle mode switching system 400. The vehicle includes an engine 101, a clutch 102, a first motor, 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 disposed between the gearbox input shaft 107 and the gearbox 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 gearbox controller 402, a motor controller 403, and an engine controller 404; wherein,

[0212] The vehicle controller 401 is configured to, when determining that the driver has a reverse intention, determine whether the vehicle satisfies a mode switching condition for switching from a series mode to a power split mode based on the vehicle condition information; and when determining that the vehicle satisfies the mode switching condition, send an engine torque adjustment request to the engine controller 404, send a clutch state holding request to the gearbox controller 402, and send a motor state holding request to the motor controller 403;

[0213] The gearbox controller 402 is configured to keep the clutch 102 in a closed state in response to the clutch state holding request; the motor controller 403 is configured to keep the first motor in a power generation state in response to the motor state holding request.

[0214] The engine controller 404 is configured to adjust the torque of the engine 101 in response to an engine torque adjustment request, so that the first synchronizer 105 meets the first gear shifting condition;

[0215] The vehicle controller 401 is further configured to, when the first synchronizer 105 meets the first gear shifting condition, send a first shifting request to the transmission controller 402 and send a motor speed adjustment request to the motor controller 403;

[0216] The transmission controller 402 is further configured to control the first synchronizer 105 to switch from the engaged gear to the power split gear in response to the first shifting request; the motor controller 403 is further configured to adjust the speed of the first motor in response to the motor speed adjustment request, so that the second synchronizer 106 meets the second gear shifting condition;

[0217] The vehicle controller 401 is further configured to send a second shifting request to the transmission controller 402 when the second synchronizer 106 meets the second gear shifting condition;

[0218] The transmission controller 402 is further configured to control the second synchronizer 106 to switch from the current gear to the reverse gear in response to the second shifting request, so that the vehicle switches from the series mode to the power split mode.

[0219] It should be noted that for the specific implementation manner of the vehicle mode switching system 400 in the embodiments of the present application, reference may be made to the specific implementation manner of the vehicle mode switching method proposed in the first aspect of the present application, which will not be elaborated here.

[0220] Fourthly, based on the same inventive concept, with reference 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.

[0221] It should be noted that for the specific implementation manner of the vehicle 500 in the embodiments of the present application, reference may be made to the specific implementation manner of the vehicle mode switching system 400 proposed in the third aspect of the present application, which will not be elaborated here.

[0222] Those skilled in the art should understand that the embodiments of the present invention can be provided as a method, an apparatus, 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.

[0223] 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 embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, and 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 processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing terminal device to generate a machine, such that the instructions executed by the processor of the computer or other programmable data processing terminal device generate a means for implementing the functions specified in one process Figure 1 one process or multiple processes and / or blocks Figure 1 or a means for implementing the functions specified in multiple blocks

[0224] 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 means, and the instruction means implements the functions specified in one process Figure 1 one process or multiple processes and / or blocks Figure 1 or the functions specified in multiple blocks

[0225] 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, 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 the functions specified in multiple blocks

[0226] Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications to these embodiments once they know the basic creative concepts. Therefore, the appended claims are intended to be construed to include the preferred embodiments and all changes and modifications that fall within the scope of the embodiments of the present invention

[0227] 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, so 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 further includes 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.

[0228] The above has introduced in detail a vehicle mode switching method, 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 it is determined that the driver has a reverse intention, based on the operating condition information of the vehicle, determine whether the vehicle meets the mode switching condition for switching from the series mode to the power split mode; When it is determined that the vehicle meets the mode switching condition, 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 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 the engaged gear to the power split gear; and adjust the 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 the current gear to the reverse 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, wherein The operating condition information includes the current driving mode, the current road condition, and the current remaining power of the power battery; The step of determining whether the vehicle meets the mode switching condition for switching from the series mode to the power split mode based on the operating condition information of the vehicle includes: When the current driving mode is the series mode, the current road condition is a preset road condition, and the current remaining power is less than the power threshold, determine that the vehicle meets the mode switching condition for switching from the series mode to the power split mode.

3. 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 engaged gear, determine that the speed ratio between the sun gear and the planet carrier is the first speed ratio; Based on the original motor torque of the first motor and the first speed ratio, determine the target engine torque of the engine; Based on a preset torque adjustment gradient, control the engine to gradually decrease from the original engine torque to the target engine torque.

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

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

6. The vehicle mode switching method according to claim 3, wherein, The step of adjusting the speed of the first motor includes: Determine the target motor speed of the first motor based on the current wheel speed of the target wheel, the current gear position of the first synchronizer, and the target gear position of the second synchronizer; Control the current motor speed of the first motor to follow the target motor speed.

7. The vehicle mode switching method according to claim 6, wherein The step of determining the target motor speed of the first motor based on the current wheel speed of the target wheel, 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, determine that the speed ratio between the sun gear and the ring gear is the second speed ratio; When the target gear position of the second synchronizer is the reverse gear position, determine that the speed ratio between the transmission input shaft and the target wheel is the third speed ratio; Based on the second speed ratio and the third speed ratio, determine the fourth speed ratio between the target wheel and the first motor; Based on the fourth speed ratio and the current wheel speed of the target wheel, determine the target motor speed of the first motor.

8. The vehicle mode switching method according to claim 6, wherein The method further includes: When the current motor speed of the first motor reaches the target motor speed, trigger the timing of the second duration for which the fluctuation amplitude of the current motor speed is less than the speed threshold; When the second duration is greater than the second duration threshold, determine that the second synchronizer meets the second gear shifting condition.

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 determine whether the vehicle meets the mode switching conditions for switching from the series mode to the power split mode based on the vehicle condition information when it is determined that the driver has a reverse intention; and when it is determined that the vehicle meets the mode switching conditions, 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 keep the clutch in a closed state in response to the clutch state holding request; the motor controller is configured to keep the first motor in a power generation state in response to the motor state holding request; The engine controller is configured to adjust the torque of the engine in response to the engine torque adjustment request so that the first synchronizer meets the first gear shifting conditions; The vehicle controller is further configured to send a first gear shifting request to the transmission controller and send a motor speed adjustment request to the motor controller when the first synchronizer meets the first gear shifting conditions; The transmission controller is further configured to control the first synchronizer to switch from the engaged gear to the power split gear in response to the first gear shifting request; the motor controller is further configured to adjust the speed of the first motor in response to the motor speed adjustment request so that the second synchronizer meets the second gear shifting conditions; The vehicle controller is further configured to send a second gear shifting request to the transmission controller when the second synchronizer meets the second gear shifting conditions; The transmission controller is further configured to control the second synchronizer to switch from the current gear to the reverse gear in response to the second gear shifting request, so that the vehicle switches from the series mode to the power split mode.

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

Images