Hybrid drive system control method, device, system, and vehicle

Abstract

The present disclosure relates to a hybrid drive system control method, device, system and vehicle. The system comprises an engine, a generator and a drive motor, and the method comprises: obtaining a current power demand; if the current power demand is greater than a first demand threshold and not greater than a second demand threshold, controlling the system to work in a dual-motor drive mode, the output capability of the drive motor being not less than the second demand threshold, and the drive distribution amount of the drive motor in the dual-motor drive mode being less than the first demand threshold. In this way, during the switching process from the dual-motor drive mode to the engine direct drive mode, when the generator unloads torque, the drive motor has a torque margin for compensating for the torque unloaded by the generator, so as to transfer the torque of the generator to the drive motor and realize the function of starting the engine by the generator. Therefore, during the mode switching process, the total output of the hybrid drive system is equal to the total demand, so as to meet the power demand of the vehicle and improve the driving experience.

Description

Technical Field

[0001] This disclosure relates to the field of hybrid technology, and more specifically, to a hybrid drive system control method, apparatus, system, and vehicle. Background Technology

[0002] With the development of electric drive technology and the improvement of charging infrastructure, hybrid vehicles are increasingly relying more on electric power while reducing the use of the internal combustion engine. A typical series-parallel architecture enables efficient operation across all scenarios: high battery level uses pure electric mode, low battery level and low speed uses series mode, and high speed uses engine direct drive mode. Hybrid drive systems typically include single-motor drive mode, dual-motor drive mode, engine direct drive mode, and series mode, switching modes according to the vehicle's power demands. Ensuring adequate power during mode switching is crucial for enhancing the driving experience. Summary of the Invention

[0003] In order to overcome the problems existing in the related technologies, this disclosure provides a hybrid power drive system control method, device, system and vehicle.

[0004] To achieve the above objectives, in a first aspect, this disclosure provides a control method for a hybrid power drive system, the system including an engine, a generator, and a drive motor, the method comprising:

[0005] Obtain the current power requirements of the system;

[0006] If the current power demand is greater than a first demand threshold and less than or equal to a second demand threshold, the system is controlled to operate in a dual-motor drive mode. When the current power demand is less than or equal to the first demand threshold, the system operates in a single-drive motor drive mode. The output capacity of the drive motor is greater than or equal to the second demand threshold, and the drive allocation of the drive motor in the dual-motor drive mode is less than the first demand threshold. This ensures that during the system's transition from the dual-motor drive mode to the engine direct drive mode, when the generator unloads torque, the drive motor has a torque margin to compensate for the torque unloaded by the generator.

[0007] Optionally, the method further includes:

[0008] When the current power demand exceeds the second demand threshold, the system is controlled to operate in engine direct drive mode.

[0009] Optionally, the drive motor and the generator are respectively connected to the battery, and the engine direct drive mode includes parallel mode and three power source mode;

[0010] The control system operates in engine direct drive mode, including:

[0011] Control the engine to start;

[0012] After the engine starts, the target mode of the system is determined from the parallel mode and the three-power source mode based on the remaining power of the battery.

[0013] Control the system to operate in the target mode.

[0014] Optionally, determining the target mode of the system from the parallel mode and the three-power-source mode based on the remaining charge of the battery includes:

[0015] If the remaining power is greater than or equal to a preset power threshold, then the driving efficiency of the system when outputting the current power demand in the parallel mode and the driving efficiency of the system when outputting the current power demand in the three-power source mode are determined.

[0016] The system's target mode is determined by the one with the greater driving efficiency between the parallel mode and the three-power-source mode.

[0017] Optionally, determining the target mode of the system from the parallel mode and the three-power-source mode based on the remaining charge of the battery further includes:

[0018] If the remaining power is less than the preset power threshold, then the parallel mode is determined as the target mode.

[0019] Optionally, the system further includes a shifting mechanism, a differential, a clutch, a drive gear, and a generator gear;

[0020] The generator is selectively connected to the drive gear or the generator gear via the shifting mechanism;

[0021] The drive gear is connected to the engine via the clutch;

[0022] The generator gear is connected to the engine;

[0023] The differential has a first end connected to the clutch, a second end connected to the drive motor, and a third end connected to the wheel.

[0024] Optionally, the current power demand is the current required torque;

[0025] The control of starting the engine includes:

[0026] The generator is controlled to unload torque and the drive motor to increase torque so that the total output torque is equal to the current required torque of the wheel, wherein the shifting mechanism is connected to the drive gear and the current required torque is constant;

[0027] If the torque of the generator is unloaded to zero, the shift mechanism is controlled to be in the neutral position, the generator is controlled to output reverse torque, and when the generator speed is less than or equal to the first preset speed, the generator is controlled to unload the reverse torque.

[0028] When the generator speed is zero, the shifting mechanism is controlled to connect with the generator gear, and the generator is controlled to apply torque to start the engine;

[0029] When the difference between the engine speed and the target speed is greater than or equal to the second preset speed, the generator is controlled to unload torque, wherein the target speed is determined based on the vehicle speed and the second preset speed is less than zero;

[0030] When the engine speed reaches the target speed, the engine is controlled to start.

[0031] In a second aspect, this disclosure provides a hybrid power drive system control device, the system including an engine, a generator, and a drive motor, the device comprising:

[0032] The acquisition module is used to acquire the current power demand of the system;

[0033] The control module is configured to control the system to operate in a dual-motor drive mode if the current power demand is greater than a first demand threshold and less than or equal to a second demand threshold. When the current power demand is less than or equal to the first demand threshold, the system operates in a single-drive motor drive mode. The output capacity of the drive motor is greater than or equal to the second demand threshold, and the drive allocation of the drive motor in the dual-motor drive mode is less than the first demand threshold. This ensures that during the system's transition from the dual-motor drive mode to the engine direct drive mode, when the generator unloads torque, the drive motor has a torque margin to compensate for the torque unloaded by the generator.

[0034] Thirdly, this disclosure provides a hybrid power drive system, comprising:

[0035] engine;

[0036] dynamo;

[0037] Drive motor; and

[0038] A controller, wherein the controller is configured to perform the steps of the hybrid drive system control method provided in the first aspect of this disclosure.

[0039] Fourthly, this disclosure provides a vehicle, including:

[0040] A hybrid power drive system, wherein the hybrid power drive system is the hybrid power drive system provided in the third aspect of this disclosure; and

[0041] wheel.

[0042] In the above technical solution, when the current power demand of the hybrid drive system is greater than a first demand threshold and less than or equal to a second demand threshold, the system drives the vehicle jointly through the generator and the drive motor (i.e., dual-motor drive mode). When the current power demand is less than or equal to the first demand threshold, the system drives the vehicle solely through the drive motor (i.e., single-motor drive mode). The output capacity of the drive motor is greater than or equal to the second demand threshold, and the drive distribution of the drive motor in the dual-motor drive mode is less than the first demand threshold. This ensures that during the transition from dual-motor drive mode to engine direct drive mode, when the generator unloads torque, the drive motor has a torque margin to compensate for the unloaded torque, transferring the generator's torque to the drive motor to start the engine. The drive motor must withstand the torque output during the time it takes for the generator's torque to transfer to the engine's output torque. Therefore, it is guaranteed that during mode switching, the total output of the hybrid drive system equals the total demand, meeting the vehicle's power requirements and improving the driving experience.

[0043] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0044] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings:

[0045] Figure 1 This is a block diagram illustrating a hybrid drive system according to an exemplary embodiment.

[0046] Figure 2 This is a flowchart illustrating a hybrid drive system method according to an exemplary embodiment.

[0047] Figure 3 This is a flowchart illustrating a hybrid drive system method according to another exemplary embodiment.

[0048] Figure 4This is a block diagram illustrating a hybrid drive system according to another exemplary embodiment.

[0049] Figure 5 This is a schematic diagram of a hybrid power drive system according to an exemplary embodiment.

[0050] Figure 6 This is a timing diagram illustrating a switching from a dual-motor drive mode to an engine direct drive mode according to an exemplary embodiment.

[0051] Figure 7 This is a schematic diagram illustrating the energy transfer of a starting engine according to an exemplary embodiment.

[0052] Figure 8 This is a schematic diagram of energy transfer in a single-motor drive mode according to an exemplary embodiment.

[0053] Figure 9 This is a schematic diagram illustrating energy transfer in a dual-motor drive mode according to an exemplary embodiment.

[0054] Figure 10 This is a schematic diagram illustrating a series mode of energy transfer according to an exemplary embodiment.

[0055] Figure 11 This is a schematic diagram illustrating energy transfer in a parallel mode according to an exemplary embodiment.

[0056] Figure 12 This is a schematic diagram of energy transfer in a three-power-source mode according to an exemplary embodiment.

[0057] Figure 13 This is a schematic diagram illustrating energy transfer in a dual-motor feedback mode according to an exemplary embodiment.

[0058] Figure 14 This is a block diagram illustrating a hybrid power drive system device according to an exemplary embodiment.

[0059] Explanation of reference numerals in the attached figures

[0060] 1. Engine 2. Generator

[0061] 3 Drive motors 4 Controllers

[0062] 5. Gear shifting mechanism 6. Differential

[0063] 7. Clutch 8. Drive gear

[0064] 9 Generator gear 10 First motor shaft

[0065] 11. Engine second gear drive gear; 12. Engine second gear driven gear

[0066] 13 Engine first gear drive gear 14 Intermediate shaft

[0067] 15 Second motor shaft 16 Second motor reduction gear shaft

[0068] 17 Second motor, first stage reduction driven gear, 19 shaft gear

[0069] 18 Second motor, two-stage reduction drive gear; 20 Intermediate shaft reduction drive gear

[0070] 21 Main reduction gear 22 Engine output shaft

[0071] 100 hybrid drive system 200 wheels

[0072] 300 battery Detailed Implementation

[0073] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0074] Figure 1 This is a block diagram illustrating a hybrid power drive system according to an exemplary embodiment. Figure 1 As shown, the hybrid drive system 100 includes an engine 1, a generator 2, a drive motor 3, and a controller 4.

[0075] The controller 4 is connected to the engine 1, the generator 2 and the drive motor 3 respectively, and is used to control the operation of the hybrid power system 100.

[0076] In this disclosure, the hybrid drive system 100 can adopt different operating modes according to different operating conditions of the vehicle, specifically including single-motor drive mode (i.e., single drive motor drive mode), dual-motor drive mode, series mode, parallel mode, three-power source mode, and dual-motor regenerative mode (i.e., energy recovery mode). The controller 4 is used to determine the corresponding operating mode according to the real-time operating conditions of the vehicle and control the hybrid drive system 100 to operate according to the determined operating mode.

[0077] Figure 2 This is a flowchart illustrating a control method for a hybrid power drive system according to an exemplary embodiment, wherein the method can be applied to a controller, for example, Figure 1 The controller 4 shown is an example. Figure 2 As shown, the above method may include S201 and S202.

[0078] In S201, the current power demand of the hybrid drive system is obtained.

[0079] In this disclosure, the current power demand can be either the current required torque of the hybrid drive system or the current required power of the hybrid drive system.

[0080] In S202, if the current power demand is greater than the first demand threshold and less than or equal to the second demand threshold, the hybrid drive system is controlled to operate in dual-motor drive mode. When the current power demand is less than or equal to the first demand threshold, the system operates in single-drive motor drive mode. The output capacity of the drive motor is greater than or equal to the second demand threshold. The drive distribution of the drive motor in dual-motor drive mode is less than the first demand threshold. This ensures that during the system's transition from dual-motor drive mode to engine direct drive mode, when the generator unloads torque, the drive motor has a torque margin to compensate for the torque unloaded by the generator.

[0081] In this disclosure, when the current power demand of the hybrid drive system is less than or equal to a first demand threshold, the hybrid drive system operates in a single-motor drive mode (i.e., a single drive motor drive mode), meaning the vehicle is driven by the drive motor. When the current power demand of the hybrid drive system is greater than the first demand threshold and less than or equal to a second demand threshold, the hybrid drive system operates in a dual-motor drive mode, meaning the vehicle is driven by both the drive motor and the generator. The first demand threshold is less than the second demand threshold. When the current power demand is the current demand torque, both the first and second demand thresholds are torque values. When the current power demand is the current demand power, both the first and second demand thresholds are power values.

[0082] The output capacity of the drive motor is greater than or equal to the second demand threshold, meaning the output capacity of the drive motor is greater than the first demand threshold. This indicates that the generator is not started for power compensation because the current power demand exceeds the output capacity of the drive motor. This design is to compensate for the generator unloading part by increasing the output of the drive motor during the process of switching from dual-motor drive mode to engine direct drive mode, since the generator unloads torque to switch to the engine start gear. Therefore, the drive motor cannot output at maximum power / torque during dual-motor drive, and the drive distribution amount (i.e., the output of the drive motor) in dual-motor drive mode is less than the first demand threshold, so that the drive motor has sufficient torque margin to compensate for the torque unloaded by the generator during mode switching.

[0083] For example, the first demand threshold is 80% of the drive motor output capacity, and the second demand threshold is 90% of the drive motor output capacity.

[0084] In the above technical solution, when the current power demand of the hybrid drive system is greater than a first demand threshold and less than or equal to a second demand threshold, the system drives the vehicle jointly through the generator and the drive motor (i.e., dual-motor drive mode). When the current power demand is less than or equal to the first demand threshold, the system drives the vehicle solely through the drive motor (i.e., single-motor drive mode). The output capacity of the drive motor is greater than or equal to the second demand threshold, and the drive distribution of the drive motor in the dual-motor drive mode is less than the first demand threshold. This ensures that during the transition from dual-motor drive mode to engine direct drive mode, when the generator unloads torque, the drive motor has a torque margin to compensate for the unloaded torque, transferring the generator's torque to the drive motor to start the engine. The drive motor must withstand the torque output during the time it takes for the generator's torque to transfer to the engine's output torque. Therefore, it is guaranteed that during mode switching, the total output of the hybrid drive system equals the total demand, meeting the vehicle's power requirements and improving the driving experience.

[0085] Figure 3 This is a flowchart illustrating a hybrid drive system control method according to another exemplary embodiment, wherein the method can be applied to a controller, for example, Figure 1 The controller 4 shown is an example. Figure 3 As shown, the above method may also include S203.

[0086] In S203, when the current power demand exceeds the second demand threshold, the hybrid drive system is controlled to operate in engine direct drive mode.

[0087] In this disclosure, when the current power demand exceeds the second demand threshold, it indicates that the dual-motor drive mode can no longer meet the vehicle's power demand. At this time, the engine can be started to drive the vehicle or to generate electricity by driving the generator through the engine, that is, to control the hybrid drive system to switch from the dual-motor drive mode to the engine direct drive mode.

[0088] In the process of switching the hybrid drive system from dual-motor drive mode to engine direct drive mode, when the generator unloads torque, the drive motor is controlled to increase torque, and when the engine loads torque, the drive motor is controlled to decrease torque, so that the total output torque of the hybrid drive system is equal to the total demand torque (i.e. the current demand torque). The current demand torque is constant, that is, the vehicle's demand torque is fixed.

[0089] To ensure the vehicle's power requirements during mode switching and improve the driving experience, the total output torque of the hybrid drive system must be equal to the total required torque. Therefore, with a fixed total required torque, the drive motor increases torque when the generator is unloading torque, and decreases torque when the engine is loading torque.

[0090] In the above implementation, during the switching process of the hybrid drive system from dual-motor drive mode to engine direct drive mode, when the generator unloads torque, the generator's torque is transferred to the drive motor to start the engine. The drive motor needs to withstand the torque output during the time it takes for the generator's torque to transfer to the engine's output torque. This ensures that during mode switching, the total output torque of the hybrid drive system equals the total required torque, meeting the vehicle's power needs and improving the driving experience.

[0091] Before introducing the specific process of switching from dual-motor drive mode to engine direct drive mode in a hybrid drive system, we will first describe the specific structure of the hybrid drive system.

[0092] like Figure 4 As shown, the hybrid drive system may further include: a shift mechanism 5, a differential 6, a clutch 7, a drive gear 8, and a generator gear 9.

[0093] like Figure 4 As shown, generator 2 is selectively connected to drive gear 8 or generator gear 9 via shift mechanism 5; drive gear 8 is connected to engine 1 via clutch 7; generator gear 9 is connected to engine 1; differential 6 has a first end connected to clutch 7, a second end connected to drive motor 3, and a third end used to connect to wheel 200; controller 4 is connected to shift mechanism 5 and clutch 7 respectively, and generator 2 and drive motor 3 are used to connect to battery 300 respectively.

[0094] Specifically, such as Figure 5 As shown (controller 4 not shown), the hybrid drive system 100 also includes a first motor shaft 10, an engine second-speed drive gear 11, an engine second-speed driven gear 12, an engine first-speed drive gear 13, an intermediate shaft 14, a second motor shaft 15, a second motor reduction gear shaft 16, a second motor first-speed reduction driven gear 17, a second motor second-speed reduction drive gear 18, a shaft gear 19, an intermediate shaft reduction drive gear 20 fixedly connected to the intermediate shaft 14, an engine output shaft 22, and a main reduction gear 21 disposed on the differential 6.

[0095] like Figure 5As shown, the generator gear 9 and the drive gear 8 are loosely fitted on the first motor shaft 10. The shifting mechanism 5 is set on the first motor shaft 10 and located between the generator gear 9 and the drive gear 8. The shifting mechanism 5 selectively engages with either the generator gear 9 or the drive gear 8. The first motor shaft 10 is connected to the generator 2.

[0096] In this disclosure, generator 2 is used to connect to battery 300. Figure 5 (not shown in the image), the shifting mechanism 5 can be a synchronizer (such as...). Figure 5 (As shown) or a gear shifting mechanism, the output end of the generator 2 is selectively connected to the generator gear 9 or the drive gear 8 via the gear shifting mechanism 5. Specifically, when it is necessary to start the engine 1 or when the engine 1 needs to drive the generator 2 to generate electricity, the gear shifting mechanism 5 can engage with the generator gear 9; when the generator 2 needs to drive the wheels 200, the gear shifting mechanism 5 can engage with the drive gear 8.

[0097] like Figure 5 As shown, the engine output shaft 22 is connected to the engine 1, the second gear drive gear 11 is loosely fitted on the engine output shaft 22, the first gear drive gear 13 is fixedly connected to the engine output shaft 22, the clutch 7 is set on the engine output shaft 22, the driving end of the clutch 7 is connected to the engine 1, and the driven end of the clutch 7 is connected to the second gear drive gear 11.

[0098] like Figure 5 As shown, the second-gear driven gear 12 of the engine is connected to the intermediate shaft 14. The intermediate shaft 14 can be connected to the differential 6 via the intermediate shaft reduction drive gear 20 fixedly connected to the intermediate shaft 14 and the main reduction gear 21 set on the differential 6. The second-gear driven gear 12 of the engine can be fixedly connected to the intermediate shaft 14 (e.g., Figure 5 (As shown), it can also be loosely connected in the intermediate shaft 14. This disclosure does not specifically limit the connection method between the engine second gear driven gear 12 and the intermediate shaft 14. The engine second gear driving gear 11 meshes with the drive gear 8 and the engine second gear driven gear 12 respectively, and the engine first gear driving gear 13 meshes with the generator gear 9.

[0099] like Figure 5As shown, the driven gear 17 of the first-stage reduction gear of the second motor and the driving gear 18 of the second-stage reduction gear of the second motor are fixedly connected to the reduction gear shaft 16 of the second motor, and the shaft gear 19 is fixedly connected to the shaft 15 of the second motor. The shaft 15 of the second motor is connected to the drive motor 3. The driven gear 17 of the first-stage reduction gear of the second motor meshes with the shaft gear 19, and the main reduction gear 21 meshes with the intermediate shaft reduction driving gear 20 and the driving gear 18 of the second-stage reduction gear of the second motor, respectively. The drive motor 3 can be mechanically connected to the differential 6 via the shaft gear 19, the driven gear 17 of the first-stage reduction gear of the second motor, the driving gear 18 of the second-stage reduction gear of the second motor, and the main reduction gear 21 in sequence. The drive motor 3 is used to connect to the battery 300. Figure 5 (Not shown in the image).

[0100] In one implementation, such as Figure 5 As shown, the generator gear 9, the engine first gear drive gear 13, the intermediate shaft reduction drive gear 20, the main reduction gear 21, and the second motor second-stage reduction drive gear 18 are arranged axially overlapping (i.e., aligned and spaced radially). The drive gear 8, the engine second gear drive gear 11, the engine second gear driven gear 12, the second motor first-stage reduction driven gear 17, and the shaft gear 19 are also arranged axially overlapping. In this way, the hybrid drive system has only two rows of gears, which effectively compresses the axial space and shortens the axial dimension of the hybrid drive system, facilitating vehicle installation and layout. This results in a simple and compact structure and a simple assembly process for the hybrid drive system.

[0101] The following is combined Figure 4 and Figure 5 The specific implementation method for controlling the hybrid drive system to operate in engine direct drive mode in S203 above will be described in detail. Specifically, the engine direct drive mode includes parallel mode and three-power source mode. In this case, the hybrid drive system can be controlled to operate in engine direct drive mode through the following steps (1) to (3):

[0102] Step (1): Start engine 1.

[0103] Step (2): After the engine 1 is started, the target mode of the hybrid drive system 100 is determined from the parallel mode and the three power source mode based on the remaining power of the battery.

[0104] Step (3): Control the hybrid drive system 100 to operate in the target mode.

[0105] The following is a detailed description of the specific implementation method for controlling the start of engine 1 in step (1) above. Specifically, the current power demand is the current torque demand, which can be achieved through steps (11) to (15):

[0106] Step (11): Control the generator 2 to unload torque and drive the motor 3 to increase torque so that the total output torque is equal to the current required torque of the wheel (i.e., the total required torque). The shift mechanism 5 is connected to the drive gear 8 (i.e., the shift mechanism 5 is in the left position), and the current required torque is constant.

[0107] Step (12): If the torque of generator 2 is unloaded to zero, control the shift mechanism 5 to be in the neutral position, control generator 2 to output reverse torque, and control generator 2 to unload reverse torque when the speed of generator 2 is less than or equal to the first preset speed.

[0108] Step (13): When the speed of generator 2 is zero, control the shift mechanism 5 to connect with generator gear 9, and control the generator 2 to load torque to start engine 1.

[0109] Step (14): When the difference between the engine speed 1 and the target speed is greater than or equal to the second preset speed, control the generator 2 to unload the torque, wherein the target speed is the speed required for the clutch 7 to engage, the target speed is determined based on the vehicle speed, and the second preset speed is less than zero.

[0110] Step (15): When the engine speed of engine 1 reaches the target speed, control engine 1 to start.

[0111] In addition, to reduce wear on the clutch 7, when the engine 1 reaches the target speed, the difference between the engine 1 speed and the wheel 200 speed is controlled within a preset speed range to align the engine speed. Here, the engine speed corresponds to the clutch input speed, and the wheel 200 speed (i.e., the wheel end speed) corresponds to the clutch output speed. Controlling the difference between the engine 1 speed and the wheel 200 speed within the preset speed range means controlling the speed difference between the clutch input and output ends within the preset speed range.

[0112] After the engine 1 is started, the clutch 7 can be engaged, and the torque applied to the engine 1 and the torque applied to the drive motor 3 can be reduced so that the total output torque is equal to the total required torque. At the same time, based on the remaining charge of the battery 300, the target mode of the hybrid drive system is determined from the parallel mode and the three-power source mode. When the torque of the engine 1 reaches the preset torque, the control system operates according to the target mode.

[0113] The following is a detailed description of the specific implementation method for determining the target mode of the hybrid drive system from the parallel mode and the three-power source mode based on the remaining power of the battery in step (2) above.

[0114] Specifically, if the remaining battery charge is greater than or equal to a preset charge threshold, the driving efficiency of the hybrid drive system when outputting the current power demand in parallel mode and the driving efficiency of the system when outputting the current power demand in three-power-source mode are determined. Then, the driving efficiency with the larger corresponding driving efficiency in parallel mode and three-power-source mode is determined as the target mode of the hybrid drive system.

[0115] If the remaining battery power is less than the preset power threshold, then the parallel mode will be determined as the target mode.

[0116] When the remaining battery power is less than a preset power threshold, it indicates that the remaining battery power is insufficient to support both the generator and the drive motor to drive the vehicle simultaneously. In this case, the generator can be stopped, meaning the hybrid drive system operates in parallel mode.

[0117] The following is a detailed description of the specific implementation method for determining the drive efficiency of the hybrid drive system when outputting the current power demand in parallel mode.

[0118] Specifically, for parallel mode, a first correspondence can be pre-established between the required torque, drive motor torque, engine torque, and drive efficiency. Based on this first correspondence, the drive efficiency, drive motor torque, and engine torque corresponding to the current required torque can be determined, serving as the first drive efficiency, the first torque, and the second torque, respectively. The first drive efficiency is the drive efficiency of the hybrid drive system when outputting the current power demand in parallel mode.

[0119] When the engine 1 and drive motor 3 distribute torque according to the first correspondence, the driving efficiency of the hybrid drive system is the highest. That is, the first correspondence records the optimal distribution of drive motor torque and engine torque that maximizes the driving efficiency of the hybrid drive system when the required torque is constant. In the first correspondence, the current required torque = the drive motor torque corresponding to the current required torque + the engine torque corresponding to the current required torque, that is, the current required torque = the first torque + the second torque.

[0120] The following is a detailed description of the specific implementation method for determining the drive efficiency of the hybrid drive system when outputting the current power demand in a three-power-source mode.

[0121] Specifically, for the three-power-source mode, a second correspondence can be pre-established between the required torque, drive motor torque, generator torque, engine torque, and drive efficiency. Based on this second correspondence, the drive efficiency, drive motor torque, generator torque, and engine torque corresponding to the current required torque can be determined, serving as the second drive efficiency, third torque, fourth torque, and fifth torque, respectively. The second drive efficiency is the drive efficiency of the hybrid drive system when outputting the current power demand in the three-power-source mode.

[0122] When the engine 1, generator 2, and drive motor 3 distribute torque according to the second correspondence, the hybrid drive system has the highest driving efficiency. That is, the second correspondence records the optimal distribution of drive motor torque, starter torque, and generator torque that maximizes the driving efficiency of the hybrid drive system when the required torque is constant. In this second correspondence, the current required torque = the drive motor torque corresponding to the current required torque + the generator torque corresponding to the current required torque + the engine torque corresponding to the current required torque, that is, the current required torque = the third torque + the fourth torque + the fifth torque.

[0123] The following is a detailed description of the specific implementation method for controlling the hybrid drive system 100 to operate in the target mode in step (3).

[0124] Specifically, if the target mode is parallel mode, then control engine 1 to output the second torque and control drive motor 3 to output the first torque.

[0125] When the target mode of the hybrid drive system is parallel mode, after the engine 1 starts, the control shift mechanism 5 is placed in the neutral position. This allows the generator 2 to be disconnected from the engine 1, eliminating no-load losses and reducing generator drag losses.

[0126] If the target mode is the three-power source mode, then control the drive motor 3 to output the third torque, the generator 2 to output the fourth torque, and the engine 1 to output the fifth torque.

[0127] The following is combined Figure 6 The timing diagram shown details the switching process from dual-motor drive mode to parallel mode, where... Figure 6 This is an example of a timing diagram for transitioning to parallel mode during slow acceleration driven by dual motors. Specifically, the switching process is divided into stages T1 to T7:

[0128] T1 phase: Dual motor drive, all system states remain unchanged;

[0129] T2 stage: The torque of generator 2 begins to be unloaded. At the same time, in order to ensure that the power of the whole vehicle meets the requirements, the torque of drive motor 3 increases. During this process, the shift mechanism 5 is still in the left position, that is, the shift mechanism 5 is connected to the drive gear 8, keeping the generator drive gear. The clutch 7 remains disengaged, that is, the engine 1 is neither driven nor generates electricity.

[0130] T3 stage: After the torque of generator 2 is completely unloaded to zero, the speed of generator 2 is at its maximum. The shift mechanism 5 is placed in the neutral position (i.e., neutral). At this time, the generator 2 is controlled to output reverse torque to reduce the speed of generator 2, in preparation for the subsequent placement of shift mechanism 5 in the right position to combine generator 2 with engine 1 which has a zero speed. When the speed of generator 2 is less than or equal to the first preset speed (i.e., the generator speed is close to zero), the reverse torque of generator 2 is unloaded. During this process, the output torque of drive motor 3 is equal to the total required torque.

[0131] T4 stage: When the speed of generator 2 drops to zero, it completes the speed alignment with engine 1. At this time, if... Figure 7 As shown, the shift mechanism 5 can be smoothly connected to the right position. After the shift mechanism 5 is successfully engaged with the generator gear 9, the torque of the generator 2 is applied to drive the engine 1 to start. During this process, the clutch 7 is not engaged and the output of the drive motor 3 is equal to the total required torque.

[0132] T5 stage: The engine speed of engine 1 increases, and when the difference between the engine speed of engine 1 and the target speed is greater than or equal to the second preset speed (i.e., the engine speed of engine 1 is close to the speed required for clutch 7 to engage), the torque of generator 1 is unloaded. During this process, clutch 7 is not engaged and the output of drive motor 3 is equal to the total required torque.

[0133] T6 stage: After the engine speed reaches the speed required for clutch 7 to engage (i.e. target speed), the engine 1 is ignited and started, clutch 7 is engaged, and the engine 1 officially participates in the driving work to output torque. At the same time, the torque of the drive motor 3 is reduced to ensure that the power of the whole vehicle meets the requirements. Under the condition of ensuring the normal operation of the engine 1, the shift mechanism 5 is moved from the right position to the middle position, thereby disconnecting the generator 2 from the generator transmission path and reducing the drag of the generator 2.

[0134] T7 stage: After reaching the preset torque, it officially enters the parallel mode, and distributes the engine torque and drive motor torque according to the most efficient allocation.

[0135] The following is combined Figure 5 The structure of the hybrid drive system is shown, and the control principle of the hybrid drive system under different operating modes is explained in detail.

[0136] When the hybrid drive system is in single-motor drive mode, such as Figure 8As shown, the shift mechanism 5 is in the neutral position, the clutch 7 is disengaged, the drive motor 3 drives the wheel 200 alone, and the engine 1 and generator 2 are both stationary (i.e. not working).

[0137] When the hybrid drive system is in dual-motor drive mode, such as Figure 9 As shown, the shift mechanism 5 is in the left position and connected to the drive gear 8, the clutch 7 is disengaged, the generator 2 and the drive motor 3 jointly drive the wheel 200, and the engine 1 remains stationary.

[0138] When the hybrid drive system is in pure electric drive mode, it can select either single-motor drive mode or dual-motor drive mode according to the load size. At the same time, engine 1 will not be towed (engine 1 is stationary). In this way, the system can reduce the power of a single motor and reduce the motor capacity without sacrificing power, thereby reducing system costs and improving drive efficiency.

[0139] When the hybrid drive system is running in series mode, such as Figure 10 As shown, the shift mechanism 5 is in the right position, the clutch 7 is disengaged, and the engine 1 engages with the generator gear 9 via the engine first gear drive gear 13 to drive the generator 2 to generate electricity. When the power demand of the drive motor 3 is greater than the power output of the generator 2, the battery 300 discharges, and the drive motor 3 drives the wheels 200; when the power demand of the drive motor 3 is less than the power output of the generator 2, the generator 2 provides power to the drive motor 3 to drive the wheels 200, and the excess power is used to charge the battery 300.

[0140] In the dual-motor drive mode, when the generator 2 drives the wheel 200, it uses the drive gear 8 to transmit power. When the engine 1 and the generator 2 work in series (i.e., in series mode), the power of the engine 1 is transmitted through the generator gear 9. That is, the drive path and the power generation path of the generator 2 are different. In this way, the speed ratio matching of the generator 2 in pure electric drive and series power generation is more flexible and better.

[0141] When the hybrid drive system is in parallel mode, such as Figure 11 As shown, the shift mechanism 5 is in the neutral position, the generator 2 is stationary, the clutch 7 is engaged, and the engine 1 transmits power to the differential 6 in sequence through the engine second gear drive gear 11, the engine second gear driven gear 12, the intermediate shaft reduction drive gear 20, and the main reduction gear 21.

[0142] When the hybrid drive system is in parallel mode, the shift mechanism 5 is in the neutral position, the generator 2 is disconnected from the engine 1, there is no no-load loss, and the generator drag loss is reduced.

[0143] When the hybrid drive system is operating in three-power source mode, such as Figure 12As shown, the shift mechanism 5 is in the left position, the clutch 7 is engaged, the generator 2 is connected to the drive gear 8 through the shift mechanism 5, and transmits power to the differential 6 through the engine second gear drive gear 11, engine second gear driven gear 12, intermediate shaft reduction drive gear 20 and main reduction gear 21, so that the generator 2, engine 1 and drive motor 3 jointly drive the wheels 200.

[0144] When the hybrid drive system is running in three power source mode, the engine 1 drives the wheel path and requires clutch 7 to transmit torque, while the generator 2 drives the wheel path and does not require clutch 7 to transmit torque. Therefore, reducing the torque capacity of clutch 7 reduces the cost of clutch 7 and improves the reliability of clutch 7.

[0145] When the vehicle brakes, the hybrid drive system enters a dual-motor regenerative braking mode, such as... Figure 13 As shown, when engine 1 is shut down, differential 6 absorbs the kinetic energy during braking and transfers it to generator 2 and drive motor 3. The two motors generate negative torque to charge battery 300, thus realizing simultaneous energy recovery of generator 2 and drive motor 3, improving energy recovery capability, and thereby improving energy utilization.

[0146] Figure 14 This is a block diagram illustrating a hybrid power drive system device according to an exemplary embodiment. The system includes an engine, a generator, and a drive motor, such as... Figure 14 As shown, the device 30 includes:

[0147] The acquisition module 301 is used to acquire the current power demand of the system;

[0148] The control module 302 is configured to control the system to operate in a dual-motor drive mode if the current power demand is greater than a first demand threshold and less than or equal to a second demand threshold. When the current power demand is less than or equal to the first demand threshold, the system operates in a single-drive motor drive mode. The output capacity of the drive motor is greater than or equal to the second demand threshold, and the drive allocation of the drive motor in the dual-motor drive mode is less than the first demand threshold. This ensures that during the system's transition from the dual-motor drive mode to the engine direct drive mode, when the generator unloads torque, the drive motor has a torque margin to compensate for the torque unloaded by the generator.

[0149] In the above technical solution, when the current power demand of the hybrid drive system is greater than a first demand threshold and less than or equal to a second demand threshold, the system drives the vehicle jointly through the generator and the drive motor (i.e., dual-motor drive mode). When the current power demand is less than or equal to the first demand threshold, the system drives the vehicle solely through the drive motor (i.e., single-motor drive mode). The output capacity of the drive motor is greater than or equal to the second demand threshold, and the drive distribution of the drive motor in the dual-motor drive mode is less than the first demand threshold. This ensures that during the transition from dual-motor drive mode to engine direct drive mode, when the generator unloads torque, the drive motor has a torque margin to compensate for the unloaded torque, transferring the generator's torque to the drive motor to start the engine. The drive motor must withstand the torque output during the time it takes for the generator's torque to transfer to the engine's output torque. Therefore, it is guaranteed that during mode switching, the total output of the hybrid drive system equals the total demand, meeting the vehicle's power requirements and improving the driving experience.

[0150] Optionally, the control module 302 is further configured to control the system to operate in engine direct drive mode when the current power demand is greater than the second demand threshold.

[0151] Optionally, the drive motor and the generator are respectively connected to the battery, and the engine direct drive mode includes parallel mode and three power source mode;

[0152] The control module 302 includes:

[0153] The first control submodule is used to control the engine start-up;

[0154] The first determining submodule is used to determine the target mode of the system from the parallel mode and the three power source mode based on the remaining power of the battery after the engine is started.

[0155] The second control submodule is used to control the system to operate in the target mode.

[0156] Optionally, the first determining submodule includes:

[0157] The second determining submodule is used to determine the driving efficiency of the system when outputting the current power demand in the parallel mode and the driving efficiency of the system when outputting the current power demand in the three power source mode if the remaining power is greater than or equal to a preset power threshold.

[0158] The third determining submodule is used to determine the system's target mode as the one with the larger driving efficiency between the parallel mode and the three-power-source mode.

[0159] Optionally, the first determining submodule further includes:

[0160] The fourth determining submodule is used to determine the parallel mode as the target mode if the remaining power is less than the preset power threshold.

[0161] Optionally, the system further includes a shifting mechanism, a differential, a clutch, a drive gear, and a generator gear;

[0162] The generator is selectively connected to the drive gear or the generator gear via the shifting mechanism;

[0163] The drive gear is connected to the engine via the clutch;

[0164] The generator gear is connected to the engine;

[0165] The differential has a first end connected to the clutch, a second end connected to the drive motor, and a third end connected to the wheel.

[0166] Optionally, the current power demand is the current required torque;

[0167] The first control submodule includes:

[0168] The third control submodule is used to control the generator unloading torque and the drive motor increasing torque so that the total output torque is equal to the current required torque of the wheel, wherein the shifting mechanism is connected to the drive gear, and the current required torque is constant;

[0169] The fourth control submodule is used to control the shift mechanism to the neutral position and control the generator to output reverse torque if the torque of the generator is unloaded to zero, and to control the generator to unload the reverse torque when the generator speed is less than or equal to the first preset speed.

[0170] The fifth control submodule is used to control the shifting mechanism to connect with the generator gear when the generator speed is zero, and to control the generator to apply torque to start the engine;

[0171] The sixth control submodule is used to control the generator to unload torque when the difference between the engine speed and the target speed is greater than or equal to a second preset speed, wherein the target speed is determined based on the vehicle speed and the second preset speed is less than zero;

[0172] The seventh control submodule is used to control the engine to start when the engine speed reaches the target speed.

[0173] Regarding the apparatus in the above embodiments, the specific manner in which each module performs its operation has been described in detail in the embodiments related to the method, and will not be elaborated upon here.

[0174] Additionally, this disclosure also provides a hybrid power drive system, comprising:

[0175] engine;

[0176] dynamo;

[0177] Drive motor; and

[0178] A controller, wherein the controller is configured to perform the steps of the hybrid drive system control method described above in this disclosure.

[0179] In addition, this disclosure also provides a vehicle, including:

[0180] A hybrid drive system 100, wherein the hybrid drive system 100 is the hybrid drive system provided in this disclosure; and

[0181] Wheel 200.

[0182] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0183] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0184] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A control method for a hybrid power drive system, characterized in that, The system includes an engine, a generator, and a drive motor. The system also includes a shifting mechanism, a differential, a clutch, a drive gear, and a generator gear. The generator is selectively connected to either the drive gear or the generator gear via the shifting mechanism. The drive gear is connected to the engine via the clutch. The generator gear is connected to the engine. The differential has a first end connected to the clutch, a second end connected to the drive motor, and a third end connected to a wheel. The method includes: Obtain the current power requirements of the system; If the current power demand is greater than a first demand threshold and less than or equal to a second demand threshold, the system is controlled to operate in a dual-motor drive mode. When the current power demand is less than or equal to the first demand threshold, the system operates in a single-drive motor drive mode. The output capacity of the drive motor is greater than or equal to the second demand threshold, and the drive allocation of the drive motor in the dual-motor drive mode is less than the first demand threshold. This ensures that during the system's transition from the dual-motor drive mode to the engine direct drive mode, when the generator unloads torque, the drive motor has a torque margin to compensate for the torque unloaded by the generator. Furthermore, when the engine loads torque, the drive motor is controlled to reduce torque so that the total output torque of the system is equal to the current demand torque. Wherein, the current power demand is the current required torque. Controlling the system to operate in engine direct drive mode includes: controlling the engine to start, including: controlling the generator to unload torque and the drive motor to increase torque, so that the total output torque is equal to the current required torque of the wheels, wherein the shifting mechanism is connected to the drive gear, and the current required torque is constant; if the generator torque is unloaded to zero, the shifting mechanism is controlled to be in the neutral position, the generator is controlled to output reverse torque, and when the generator speed is less than or equal to a first preset speed, the generator is controlled to unload the reverse torque; when the generator speed is zero, the shifting mechanism is controlled to be connected to the generator gear, and the generator is controlled to load torque to start the engine; when the difference between the engine speed and the target speed is greater than or equal to a second preset speed, the generator is controlled to unload torque, wherein the target speed is determined based on the vehicle speed, and the second preset speed is less than zero; when the engine speed reaches the target speed, the engine is controlled to start.

2. The method according to claim 1, characterized in that, The method further includes: When the current power demand exceeds the second demand threshold, the system is controlled to operate in engine direct drive mode.

3. The method according to claim 2, characterized in that, The drive motor and the generator are respectively connected to the battery, and the engine direct drive mode includes parallel mode and three power source mode; The control system for operating in engine direct drive mode also includes: After the engine starts, the target mode of the system is determined from the parallel mode and the three-power source mode based on the remaining power of the battery. Control the system to operate in the target mode.

4. The method according to claim 3, characterized in that, The step of determining the target mode of the system from the parallel mode and the three-power-source mode based on the remaining power of the battery includes: If the remaining power is greater than or equal to a preset power threshold, then the driving efficiency of the system when outputting the current power demand in the parallel mode and the driving efficiency of the system when outputting the current power demand in the three power source mode are determined. The system's target mode is determined by the one with the greater driving efficiency between the parallel mode and the three-power-source mode.

5. The method according to claim 4, characterized in that, The step of determining the target mode of the system from the parallel mode and the three-power source mode based on the remaining power of the battery further includes: If the remaining power is less than the preset power threshold, then the parallel mode is determined as the target mode.

6. A hybrid power drive system control device, characterized in that, The system includes an engine, a generator, and a drive motor. It also includes a shift mechanism, a differential, a clutch, a drive gear, and a generator gear. The generator is selectively connected to either the drive gear or the generator gear via the shift mechanism. The drive gear is connected to the engine via the clutch. The generator gear is connected to the engine. The differential has a first end connected to the clutch, a second end connected to the drive motor, and a third end connected to a wheel. The device includes: The acquisition module is used to acquire the current power demand of the system; The control module is configured to control the system to operate in a dual-motor drive mode if the current power demand is greater than a first demand threshold and less than or equal to a second demand threshold. When the current power demand is less than or equal to the first demand threshold, the system operates in a single-drive motor drive mode. The output capacity of the drive motor is greater than or equal to the second demand threshold, and the drive allocation of the drive motor in the dual-motor drive mode is less than the first demand threshold. This ensures that during the system's transition from the dual-motor drive mode to the engine direct drive mode, when the generator unloads torque, the drive motor has a torque margin to compensate for the torque unloaded by the generator. Furthermore, when the engine loads torque, the control module reduces the torque of the drive motor so that the total output torque of the system equals the current demand torque. Wherein, the current power demand is the current required torque, and the control module includes a first control submodule for controlling the engine start, the first control submodule including: The third control submodule is used to control the generator unloading torque and the drive motor increasing torque so that the total output torque is equal to the current required torque of the wheel, wherein the shifting mechanism is connected to the drive gear, and the current required torque is constant; The fourth control submodule is used to control the shift mechanism to the neutral position and control the generator to output reverse torque if the torque of the generator is unloaded to zero, and to control the generator to unload the reverse torque when the generator speed is less than or equal to the first preset speed. The fifth control submodule is used to control the shifting mechanism to connect with the generator gear when the generator speed is zero, and to control the generator to apply torque to start the engine; The sixth control submodule is used to control the generator to unload torque when the difference between the engine speed and the target speed is greater than or equal to a second preset speed, wherein the target speed is determined based on the vehicle speed and the second preset speed is less than zero; The seventh control submodule is used to control the engine to start when the engine speed reaches the target speed.

7. A hybrid power drive system, characterized in that, include: engine; dynamo; Drive motor; as well as A controller, wherein the controller is configured to perform the steps of the method according to any one of claims 1-5.

8. A vehicle, characterized in that, include: A hybrid power drive system, wherein the hybrid power drive system is the hybrid power drive system according to claim 7; And wheels.

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