Powertrain, Hybrid Electric Vehicles and Their Control Methods

Abstract

This application relates to a power transmission device, a hybrid electric vehicle, and a control method thereof. The power transmission device includes: an engine, a generator, a drive motor, a planetary gear transmission mechanism, a synchronizer, a brake, a first drive shaft, a second drive shaft, first and third gear output gears, a second gear input gear, and a second gear output gear meshing with the second gear input gear. The engine is connected to the generator via the first drive shaft, and drives the first drive shaft to achieve the generator's power generation function. The planetary gear transmission mechanism includes a ring gear, planetary gears, a planet carrier, and a sun gear connected within the ring gear. The sun gear and synchronizer are fixedly connected to the first drive shaft. The first and third gear output gears and the second gear output gear are fixedly connected to the second drive shaft, and the first and third gear output gears also mesh with the planet carrier. The drive motor is connected to the second drive shaft. This device not only provides multiple driving modes but also effectively improves power and fuel economy.

Description

Technical Field

[0001] This application belongs to the field of automotive technology, specifically relating to a power transmission device, a hybrid electric vehicle, and a control method thereof. Background Technology

[0002] With increasing global pressure on oil and energy resources, hybrid technology has emerged as another breakthrough for alleviating this pressure. Current hybrid systems are mainly categorized into three types: series, parallel, and series-parallel hybrid systems.

[0003] Series-type systems rely on an engine to drive a generator to produce electricity, which is then directly supplied to the drive motor to propel the vehicle or stored in the battery. This system has a simple structure, and the engine torque is decoupled from the wheel ends, effectively controlling the engine to operate in its high-efficiency range. However, due to the long drive chain, the system suffers from high efficiency losses and limited fuel economy. Furthermore, when the vehicle is required to cover various operating conditions, the power selection of the drive motor, generator, and engine needs to be significant, leading to increased costs and layout issues.

[0004] Parallel-type motors rely on both the engine and the drive motor to output power to meet the vehicle's power needs. This reduces the torque requirements of the motor and can effectively reduce battery size. However, because the engine speed cannot be decoupled from the vehicle speed, the ability to adjust the engine's high-efficiency range is limited, resulting in limited fuel-saving effects.

[0005] Hybrid systems combine the advantages of series and parallel systems, allowing for customized design based on vehicle requirements. The chosen solution can offer significant fuel savings while meeting overall vehicle power performance needs. The downside is that, depending on the system's complexity, control becomes more challenging. Summary of the Invention

[0006] The purpose of this application is to provide a power transmission device, a hybrid electric vehicle and a control method thereof, which can not only provide multiple driving modes, but also effectively improve power and economy.

[0007] The first aspect of this application discloses a power transmission device, comprising: an engine, a generator, a drive motor, a planetary gear transmission mechanism, a synchronizer, a brake, a first drive shaft, a second drive shaft, a first and third gear output gear, a second gear input gear, and a second gear output gear meshing with the second gear input gear; wherein, the engine is connected to the generator via the first drive shaft, and drives the first drive shaft through the engine to realize the generator's power generation function; the planetary gear transmission mechanism includes a gear ring, and planet gears, a planet carrier, and a sun gear connected within the gear ring; the sun gear and the synchronizer are fixedly connected to the first drive shaft; the first and third gear output gears, the second gear input gear, and the third gear output gear meshing with the second gear input gear are ... The output gears are fixedly connected to the second transmission shaft, and the first and third gear output gears also mesh with the planetary carrier; the drive motor is connected to the second transmission shaft and transmits power to the drive wheels through the second transmission shaft; when the brake is closed, the gear ring is fixedly connected to the first transmission shaft and moves with the first transmission shaft; when the brake is open, the gear ring moves freely on the first transmission shaft; when the synchronizer is closed, one of the planetary carrier and the second gear input gear is fixed to the first transmission shaft, and the other is freely mounted on the first transmission shaft; when the synchronizer is completely disengaged, both the planetary carrier and the second gear input gear are freely mounted on the first transmission shaft.

[0008] In one exemplary embodiment of this application, the power transmission device further includes a main reduction gear set, a drive motor drive shaft, a drive motor input gear, and a drive motor output gear. The main reduction gear set is drivenly connected to the second drive shaft. The drive motor is drivenly connected to the drive motor input gear through the drive motor drive shaft. The drive motor input gear meshes with the drive motor output gear. The drive motor output gear is drivenly connected to the main reduction gear set.

[0009] In one exemplary embodiment of this application, the output gear of the drive motor is the second-gear output gear.

[0010] In one exemplary embodiment of this application, the power transmission device further includes a third transmission shaft, and the output gear of the drive motor and the main reduction gear set are both fixedly connected to the third transmission shaft.

[0011] In one exemplary embodiment of this application, the main reduction gear set includes a first main reduction input gear, a second main reduction input gear, and a main reduction output gear; wherein the first main reduction input gear and the second main reduction input gear are both meshed with the main reduction output gear; the first main reduction input gear is fixedly connected to the second transmission shaft; and the second main reduction input gear is fixedly connected to the third transmission shaft.

[0012] In one exemplary embodiment of this application, the output gear of the drive motor is fixedly connected to the second transmission shaft.

[0013] In one exemplary embodiment of this application, the power transmission device further includes a generator input gear and a generator output gear. The generator input gear is fixedly connected to the generator drive shaft of the generator, the generator input gear meshes with the generator output gear, and the generator output gear is connected to the first drive shaft.

[0014] In one exemplary embodiment of this application, the synchronizer is a double-sided synchronizer, located between the planetary carrier and the second-gear input gear. When the planetary carrier is closed on one side of the double-sided synchronizer, the planetary carrier is fixed to the first drive shaft, and the second-gear input gear is loosely fitted on the first drive shaft. When the second-gear input gear is closed on the other side of the double-sided synchronizer, the second-gear input gear is fixed to the first drive shaft, and the planetary carrier is loosely fitted on the first drive shaft. When both sides of the double-sided synchronizer are disconnected from the planetary carrier and the second-gear input gear, both the planetary carrier and the second-gear input gear are loosely fitted on the first drive shaft.

[0015] In one exemplary embodiment of this application, the synchronizer includes a first single-sided synchronizer and a second single-sided synchronizer, both of which are connected to the first drive shaft. When the first single-sided synchronizer is closed with the planetary carrier, the planetary carrier is fixedly connected to the first drive shaft. When the first single-sided synchronizer is disconnected from the planetary carrier, the planetary carrier is loosely fitted onto the first drive shaft. When the second single-sided synchronizer is closed with the second-gear input gear, the second-gear input gear is fixedly connected to the first drive shaft. When the second single-sided synchronizer is disconnected from the second-gear input gear, the second-gear input gear is loosely fitted onto the first drive shaft.

[0016] A second aspect of this application discloses a hybrid electric vehicle, including drive wheels and the aforementioned power transmission device, the power transmission device being used to drive the drive wheels.

[0017] A third aspect of this application discloses a control method for a hybrid electric vehicle, the control method being used to control the aforementioned hybrid electric vehicle; wherein, the control method enables the hybrid electric vehicle to switch between pure electric mode, range-extended mode, engine direct drive mode, and hybrid mode by controlling the opening and closing of the brake and the synchronizer.

[0018] In one exemplary embodiment of this application, switching the hybrid vehicle to pure electric mode includes: controlling the brake to disengage and controlling the synchronizer to fully disengage, so as to transmit the power of the drive motor to the second drive shaft and transmit the power to the drive wheels through the second drive shaft.

[0019] In one exemplary embodiment of this application, switching the hybrid vehicle to range-extending mode includes: controlling the brake to disengage and controlling the synchronizer to fully disengage, so as to transmit the power of the engine to the generator through the first drive shaft to achieve idle power generation; starting the drive motor and transmitting the power of the drive motor to the second drive shaft, and transmitting the power to the drive wheels through the second drive shaft.

[0020] In one exemplary embodiment of this application, the hybrid vehicle switching to engine direct drive mode includes a first gear engine direct drive mode, a second gear engine direct drive mode, and a third gear engine direct drive mode; wherein, the hybrid vehicle switching to the first gear engine direct drive mode includes: controlling the brake to close, controlling the synchronizer to fully disengage, so that the engine power is sequentially transmitted through the first drive shaft and the first and third gear output gears to the second drive shaft, and then transmitted to the drive wheels through the second drive shaft; the hybrid vehicle switching to the second gear engine direct drive mode includes: controlling the... When the brake is disengaged, the synchronizer is controlled to close with the second-gear output gear, so that the engine power is transmitted sequentially through the first drive shaft, the second-gear input gear, and the second-gear output gear to the second drive shaft, and then transmitted to the drive wheels through the second drive shaft; the hybrid vehicle switching to the third-gear engine direct drive mode includes: disengaging the brake, controlling the synchronizer to close with the first and third-gear output gears, so that the engine power is transmitted sequentially through the first drive shaft, the planetary carrier, and the first and third-gear output gears to the second drive shaft, and then transmitted to the drive wheels through the second drive shaft.

[0021] In one exemplary embodiment of this application, the hybrid vehicle switching to a hybrid drive mode includes a first-gear hybrid drive mode, a second-gear hybrid drive mode, and a third-gear hybrid drive mode. Specifically, switching the hybrid vehicle to the first-gear hybrid drive mode includes: when the hybrid vehicle switches to the first-gear engine direct drive mode, starting the drive motor and transmitting the power of the drive motor to the second drive shaft, and then transmitting the power to the drive wheels via the second drive shaft; switching the hybrid vehicle to the second-gear hybrid drive mode includes: when the hybrid vehicle switches to the second-gear engine direct drive mode, starting the drive motor and transmitting the power of the drive motor to the second drive shaft, and then transmitting the power to the drive wheels via the second drive shaft; switching the hybrid vehicle to the third-gear hybrid drive mode includes: when the hybrid vehicle switches to the third-gear engine direct drive mode, starting the drive motor and transmitting the power of the drive motor to the second drive shaft, and then transmitting the power to the drive wheels via the second drive shaft.

[0022] The proposed solution has the following beneficial effects:

[0023] In this embodiment, the power transmission device can change the transmission mode of the planetary gear transmission mechanism by controlling the opening and closing of the brake and synchronizer, ultimately achieving a three-speed engine direct drive mode, a four-speed single-motor pure electric mode, a three-speed hybrid drive mode, and a series mode, which can effectively improve power and economy; overcome the influence of the characteristic parameters of the planetary gear transmission mechanism on the selection of the gear ratio; and achieve uninterrupted gear shifting. The gear combination achieved through the planetary gear transmission mechanism can effectively reduce the axial dimension of the power transmission device. Furthermore, the engine and generator achieve single-stage gear speed increase and torque reduction through the first drive shaft, which can effectively reduce the size of the generator.

[0024] Other features and advantages of this application will become apparent from the following detailed description, or may be learned in part from practice of this application.

[0025] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0026] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0027] Figure 1 A schematic diagram of the power transmission device according to Embodiment 1 of this application is shown.

[0028] Figure 2 A schematic diagram of the power transmission device according to Embodiment 2 of this application is shown.

[0029] Figure 3 A schematic diagram of the power transmission device described in Embodiment 3 of this application is shown.

[0030] Figure 4 A schematic diagram of the power transmission device described in Embodiment 4 of this application is shown.

[0031] Explanation of reference numerals in the attached figures:

[0032] 1. Engine; 2. Generator; 3. Drive motor; 4. First drive shaft; 5. Second drive shaft; 6. Generator drive shaft; 7. Drive motor drive shaft; 8. Sun gear; 9. Planet gears; 10. Ring gear; 11. Planet carrier; 12. First and third gear output gears; 13. Second gear input gear; 14. Second gear output gear; 15. Generator input gear; 16. Generator output gear; 17. Drive motor input gear; 18. Main reduction input gear; 19. Main reduction output gear; 20. Differential; 21. Half shaft; 22. Drive motor output gear; 23. Third drive shaft; B. Brake; S. Double-sided synchronizer; S1. First single-sided synchronizer; S2. Second single-sided synchronizer. Detailed Implementation

[0033] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided to make this application more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art.

[0034] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a thorough understanding of embodiments of this application. However, those skilled in the art will recognize that the technical solutions of this application can be practiced without one or more of the specific details, or other methods, components, apparatuses, steps, etc., can be employed. In other instances, well-known methods, apparatuses, implementations, or operations are not shown or described in detail to avoid obscuring various aspects of this application.

[0035] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments. It should be noted that the technical features involved in the various embodiments described below can be combined with each other as long as they do not conflict with each other. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present application, and should not be construed as limiting the present application.

[0036] Example 1

[0037] like Figure 1 As shown in the figure, this embodiment discloses a hybrid electric vehicle, which includes a power transmission device and drive wheels. The power transmission device provides driving force to the drive wheels.

[0038] In some embodiments, the power transmission device includes an engine 1, a generator 2, and a drive motor 3. The engine 1 can drive the generator 2 to generate electricity, which is then directly supplied to the drive motor 3 to drive the vehicle or stored in a power battery; alternatively, the engine 1 and the drive motor 3 can jointly output power to meet the vehicle's power requirements.

[0039] The following is a detailed description of the transmission connection method of engine 1, generator 2, and drive motor 3:

[0040] In some embodiments, the power transmission device further includes a first drive shaft 4. The engine 1 is connected to the generator 2 via the first drive shaft 4, and the engine 1 drives the first drive shaft 4 to realize the power generation function of the generator 2.

[0041] For example, the power transmission device also includes a generator input gear 15 and a generator output gear 16 that meshes with the generator input gear 15. The generator input gear 15 is fixedly connected to the generator drive shaft 6 of the generator 2. The generator input gear 15 meshes with the generator output gear 16. The generator output gear 16 is connected to the first drive shaft 4, thereby realizing the connection of the first-stage fixed-axis transmission gears.

[0042] In some embodiments, the power transmission device further includes a planetary gear transmission mechanism. The planetary gear transmission mechanism includes a ring gear 10, and planetary gears 9, a planet carrier 11, and a sun gear 8 connected within the ring gear 10. The sun gear 8 is fixedly connected to the first transmission shaft 4 and is capable of moving with the first transmission shaft 4.

[0043] Furthermore, the power transmission device also includes a synchronizer and a brake B. The synchronizer is fixedly connected to the first transmission shaft 4, and the brake B is used to lock the gear ring 10.

[0044] For example, the synchronizer is a double-sided synchronizer S, which is located between the planetary carrier 11 and the second-gear input gear 13. The double-sided synchronizer S can be moved left and right to control its engagement or disengagement with the planetary carrier 11 or the second-gear input gear 13. Compared with a single-sided synchronizer, the use of a double-sided synchronizer S allows for a higher degree of integration of the power transmission device in the axial direction.

[0045] It should be understood that when one side of the planetary carrier 11 of the double-sided synchronizer S is closed, the planetary carrier 11 is fixed on the first drive shaft 4, and the second gear input gear 13 is loosely fitted on the first drive shaft 4; when the other side of the double-sided synchronizer S has the second gear input gear 13 closed, the second gear input gear 13 is fixed on the first drive shaft 4, and the planetary carrier 11 is loosely fitted on the first drive shaft 4; when both sides of the double-sided synchronizer S are disconnected from the planetary carrier 11 and the second gear input gear 13, both the planetary carrier 11 and the second gear input gear 13 are loosely fitted on the first drive shaft 4.

[0046] When brake B is closed, the gear ring 10 is fixedly connected to the first drive shaft 4 and moves with the first drive shaft 4; when brake B is open, the gear ring 10 is loosely fitted on the first drive shaft 4.

[0047] Furthermore, the power transmission device also includes a first and third gear output gear 12, a second gear input gear 13, and a second gear output gear 14 that meshes with the second gear input gear 13. The first and third gear output gear 12 meshes with the planetary carrier 11, and the second gear input gear 13 is mounted on the first drive shaft 4.

[0048] For example, the planetary carrier 11 and the first and third gear output gear 12 are a pair of meshing gears; the second gear input gear 13 and the second gear output gear 14 are a pair of meshing gears.

[0049] It should be understood that when the synchronizer is closed, one of the planetary carrier 11 and the second gear input gear 13 is fixed on the first drive shaft 4, while the other is loosely fitted on the first drive shaft 4; when the synchronizer is completely disengaged, both the planetary carrier 11 and the second gear input gear 13 are loosely fitted on the first drive shaft 4.

[0050] In some embodiments, the power transmission device further includes a second drive shaft 5, with a first-gear third-gear 12 and a second-gear second-gear 14 fixedly connected to the second drive shaft 5. The drive motor 3 is connected to the second drive shaft 5 and transmits power to the drive wheels through the second drive shaft 5.

[0051] For example, the power transmission device also includes a main reduction gear set, a drive motor drive shaft 7, a drive motor input gear 17, and a drive motor output gear. The main reduction gear set is driven and connected to the second drive shaft 5. The drive motor 3 is driven and connected to the drive motor input gear 17 through the drive motor drive shaft 7. The drive motor input gear 17 meshes with the drive motor output gear, and the drive motor output gear 22 is driven and connected to the main reduction gear set.

[0052] In some embodiments, the drive motor output gear is a second-gear output gear 14, that is, the drive motor output gear and the second-gear output gear 14 are shared, thereby reducing the number of gears, reducing the transmission chain length, and effectively controlling the engine 1 to work in the high-efficiency range.

[0053] The main reduction gear set includes a main reduction input gear 18 and a main reduction output gear 19, which are a pair of meshing gears. The main reduction input gear 18 is connected to the second transmission shaft 5, and the main reduction output gear 19 meshes with the main reduction input gear 18.

[0054] In some embodiments, the power transmission device further includes a differential 20 and a half-shaft 21. The differential 20 and the half-shaft 21 are connected to the main reduction output gear 19, and the half-shaft 21 is used to connect to the drive wheels.

[0055] The working principle of power transmission devices will be explained in detail below:

[0056] When all brakes B are in the off state and the double synchronizer S is in the completely off state (the double synchronizer S is not connected to the planetary carrier 11 and the second gear input gear 13), the drive motor 3 transmits power to the drive motor input gear 17 through the drive motor transmission shaft 7, and then transmits power to the drive wheels through the meshing second gear output gear 14, the second transmission shaft 5, the main reduction input gear 18, the main reduction output gear 19, the differential 20 and the half shaft 21, thus realizing pure electric drive.

[0057] When brakes B are both disengaged and the dual synchronizers S are completely disengaged (the dual synchronizers S are not connected to the planetary carrier 11 or the second-gear input gear 13), the power from engine 1 is transmitted to generator 2 via the first drive shaft 4, generator output gear 16, and generator input gear 15 to achieve idle power generation. If, at this time, drive motor 3 transmits power to drive motor input gear 17 via drive motor drive shaft 7, and then transmits power to drive wheels via the meshing second-gear output gear 14, main reduction input gear 18, main reduction output gear 19, differential 20, and half-shaft 21, range-extended drive can be achieved.

[0058] When brake B is closed and the dual synchronizer S is fully disengaged (the dual synchronizer S is not connected to the planetary carrier 11 or the second-gear input gear 13), the power of engine 1 is transmitted to the first drive shaft 4. Because brake B is closed, the ring gear 10 is locked, and the power of engine 1 is transmitted to the second drive shaft 5 through the sun gear 8, the planetary carrier 11, and the meshing first and third-gear output gears 12. Then, it is transmitted to the wheels through the main reduction input gear 18, the main reduction output gear 19, the differential 20, and the half-shaft 21, realizing the engine 1 driving in one gear.

[0059] When brake B is disengaged, and the dual synchronizer S moves to engage with planetary carrier 11 and disengages from second-gear input gear 13, power from engine 1 is transmitted to the first drive shaft 4. Because the dual synchronizer S is engaged with planetary carrier 11, planetary carrier 11 and first drive shaft 4 are locked. Power from engine 1 is then transmitted to the second drive shaft 5 via planetary carrier 11 and its meshing first and third-gear output gears 12. Finally, power is transmitted to the wheels via the main reduction input gear 18, main reduction output gear 19, differential 20, and half-shaft 21, achieving engine 1 drive in one gear.

[0060] When brake B is disengaged, the double synchronizer S moves to disengage from planetary carrier 11 and engages with second-gear input gear 13; power from engine 1 is transmitted to the first drive shaft 4. Because the double synchronizer S is engaged with second-gear input gear 13, second-gear input gear 13 and the first drive shaft 4 are locked. Power from engine 1 is then transmitted to the second drive shaft 5 via second-gear input gear 13 and its meshing second-gear output gear 14. Finally, power is transmitted to the drive wheels via the main reduction input gear 18, main reduction output gear 19, differential 20, and half-shaft 21, achieving engine 1 drive in one gear.

[0061] In addition, when the engine 1 is driven in three different gears, the drive motor 3 and the generator 2 can also participate in driving or generating electricity, thereby realizing a hybrid drive mode with three gears.

[0062] In summary, the powertrain of this embodiment features three engine 1 direct drive modes, one pure electric mode, a series range extender mode, three hybrid drive modes, and multiple operating modes such as regenerative braking and parking power generation. It can automatically switch between different modes based on battery SOC, pedal opening, vehicle speed, and other conditions, effectively improving power and fuel economy. Secondly, the generator 2 and engine 1 utilize a single-stage gear for speed increase and torque reduction, effectively reducing the size of the generator 2 and overcoming the influence of planetary gear set characteristic parameters on gear ratio selection. Furthermore, the torque of the starting drive motor 3 can be directly output to the drive wheels, resulting in fast torque response and enabling uninterrupted gear shifting. Additionally, the planetary gear set for gear combination effectively reduces axial dimensions, and the two sets of meshing gears for the three gears of engine 1 effectively reduce the number of meshing gears, covering both HEV and PHEV models, demonstrating good platform compatibility.

[0063] Example 2

[0064] like Figure 2 As shown, the hybrid electric vehicle in this embodiment is largely the same as the hybrid electric vehicle in Embodiment 1. The difference is that the transmission method of the drive motor 3 of the power transmission device in this embodiment is the same as that of the drive motor 3 of the power transmission device in Embodiment 1, which allows the drive motor 3 to directly input power to the main reduction gear set, further accelerating the torque response. Moreover, the arrangement position of the drive motor 3 is not affected by the second gear output gear.

[0065] Furthermore, the main reduction gear set includes a first main reduction input gear 18a, a second main reduction input gear 18b, and a main reduction output gear 19; wherein, the first main reduction input gear 18a and the second main reduction input gear 18b are both meshed with the main reduction output gear 19; the first main reduction input gear 18a is fixedly connected to the second transmission shaft 5; and the second main reduction input gear 18b is fixedly connected to the third transmission shaft 23.

[0066] For other structures of the power transmission device, please refer to Embodiment 1, which will not be repeated here.

[0067] Example 3

[0068] like Figure 3 As shown, the hybrid vehicle in this embodiment is largely the same as the hybrid vehicle in Embodiment 1, except that the transmission method of the drive motor 3 in the power transmission device of this embodiment is different from that of the drive motor 3 in the power transmission device of Embodiment 1. Specifically:

[0069] In this embodiment, the drive motor output gear 22 is fixedly connected to the second transmission shaft 5, and transmits power to the drive wheels through the second transmission shaft 5, the main reduction gear set, the differential 20 and the half shaft 21, so that the arrangement position of the drive motor 3 is not affected by the main reduction gear set.

[0070] For example, the main reduction input gear 18 of the main reduction gear set is located at one end of the second transmission shaft 5, the drive motor output gear 22 is located at the other end of the second transmission shaft 5, and the second gear output gear 14 and the first and third gear output gears are located between the main reduction input gear 18 and the drive motor output gear 22.

[0071] For other structures of the power transmission device, please refer to Embodiment 1, which will not be repeated here.

[0072] Example 4

[0073] The hybrid vehicle in this embodiment is largely the same as the hybrid vehicle in Embodiment 1, except that the synchronizer of the powertrain in this embodiment is different from that in Embodiment 1. Specifically:

[0074] like Figure 4 As shown, in this embodiment, the synchronizer includes a first single-sided synchronizer S1 and a second single-sided synchronizer S2, both of which are connected to the first drive shaft 4. The first single-sided synchronizer S1 is located on the side of the second gear input gear 13 closer to the planetary carrier 11, and the second single-sided synchronizer S2 is located on the side of the second gear input gear 13 away from the planetary carrier 11.

[0075] It should be understood that using a single-sided synchronizer allows for more flexible arrangement of the synchronizers compared to a double-sided synchronizer S1. Specifically, when the first single-sided synchronizer S1 is closed with the planetary carrier 11, the planetary carrier 11 is fixedly connected to the first drive shaft 4 and can move with the first drive shaft 4; when the first single-sided synchronizer S1 is disconnected from the planetary carrier 11, the planetary carrier 11 is loosely fitted on the first drive shaft 4. When the second single-sided synchronizer S2 is closed with the second-gear input gear 13, the second-gear input gear 13 is fixedly connected to the first drive shaft 4 and can move with the first drive shaft 4; when the second single-sided synchronizer S2 is disconnected from the second-gear input gear 13, the second-gear input gear 13 is loosely fitted on the first drive shaft 4.

[0076] For other structures of the power transmission device, please refer to Embodiment 1, Embodiment 2 or Embodiment 3, which will not be repeated here.

[0077] Example 5

[0078] This embodiment provides a control method for a hybrid electric vehicle, which is used to control the hybrid electric vehicle as described in Embodiments 1, 2, 3, and 4. The control method enables the hybrid electric vehicle to switch between pure electric mode, range-extended mode, engine 1 direct drive mode, and hybrid mode by controlling the opening and closing of brake B and synchronizer.

[0079] In this embodiment, switching the hybrid vehicle to pure electric mode includes:

[0080] Start the drive motor 3, disengage the control brake B, and completely disengage the control synchronizer. This allows the power of the drive motor 3 to be directly transmitted to the second drive shaft 5. The power is then transmitted sequentially through the second drive shaft 5 to the drive wheels via the main reduction input gear 18, the main reduction output gear 19, the differential 20, and the half-shaft 21, thus achieving the transmission of one gear of the engine 1 drive to the drive wheels.

[0081] In this embodiment, switching the hybrid vehicle to range-extended mode includes:

[0082] Start engine 1, disengage brake B, and fully disconnect synchronizer. Power from engine 1 is transmitted to generator 2 via first drive shaft 4 to achieve idle-speed power generation. Start drive motor 3 and transmit power from drive motor 3 to second drive shaft 5. Power is then transmitted sequentially through second drive shaft 5 via main reduction input gear 18, main reduction output gear 19, differential 20, and half-shaft 21 to the drive wheels, achieving one gear of engine 1 drive transmission to the drive wheels.

[0083] In this embodiment, the hybrid vehicle switching to engine 1 direct drive mode includes engine 1 direct drive mode in first gear, engine 1 direct drive mode in second gear, and engine 1 direct drive mode in third gear.

[0084] Among them, the switching of hybrid vehicles to the first gear, engine 1 direct drive mode, includes:

[0085] Start engine 1, close brake B, and fully disconnect synchronizer so that the power of engine 1 is transmitted sequentially through first drive shaft 4 and first and third gear output gear 12 to second drive shaft 5. The power is then transmitted sequentially through second drive shaft 5 through main reduction input gear 18, main reduction output gear 19, differential 20, and half shaft 21 to drive wheels, thus realizing the transmission of engine 1 drive to drive wheels in one gear.

[0086] In this embodiment, when the synchronizer is a double-sided synchronizer S, the double-sided synchronizer S moves to separate from the planet carrier 11 and from the second gear input gear 13; when the synchronizer is two single-sided synchronizers, the two single-sided synchronizers separate from the planet carrier 11 and the second gear input gear 13 respectively.

[0087] Switching a hybrid vehicle to engine-first direct drive mode in second gear includes:

[0088] Start engine 1, control brake B to disengage, control synchronizer to close with second gear input gear 13, and fix second gear input gear 13 on first drive shaft 4. Planet carrier 11 is loosely fitted on first drive shaft 4, so that the power of engine 1 is transmitted sequentially through first drive shaft 4, second gear input gear 13, and second gear output gear 14 to second drive shaft 5, and then through second drive shaft 5 to drive wheels.

[0089] When a hybrid vehicle switches to the third gear, engine 1 direct drive mode, it includes:

[0090] Start engine 1, control brake B to disengage, control synchronizer to close with planetary carrier 11, and fix planetary carrier 11 on first drive shaft 4, second gear input gear 13 loosely fitted on first drive shaft 4; thereby, the power of engine 1 is transmitted sequentially through first drive shaft 4, planetary carrier 11, first and third gear output gears 12 to second drive shaft 5, and then through second drive shaft 5 to drive wheels.

[0091] In this embodiment, switching a hybrid vehicle to a hybrid drive mode includes a first-gear hybrid drive mode, a second-gear hybrid drive mode, and a third-gear hybrid drive mode.

[0092] Among them, the hybrid drive mode for hybrid vehicles switching to the first gear includes:

[0093] When the hybrid vehicle switches to the first gear engine 1 direct drive mode, the drive motor 3 is started, and the power of the drive motor 3 is transmitted to the second drive shaft 5, and the power is transmitted to the drive wheels through the second drive shaft 5.

[0094] Switching a hybrid vehicle to the second-level hybrid drive mode includes:

[0095] When the hybrid vehicle switches to the second gear engine 1 direct drive mode, the drive motor 3 is started, and the power of the drive motor 3 is transmitted to the second drive shaft 5, and the power is transmitted to the drive wheels through the second drive shaft 5.

[0096] The hybrid vehicle switches to the third hybrid drive mode, which includes:

[0097] When the hybrid vehicle switches to the third gear engine 1 direct drive mode, the drive motor 3 is started, and the power of the drive motor 3 is transmitted to the second drive shaft 5, and the power is transmitted to the drive wheels through the second drive shaft 5.

[0098] In this application, unless otherwise expressly specified and limited, the terms "assembly," "connection," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0099] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. "A plurality of" means two or more, unless otherwise explicitly specified. The terms "some embodiments," "exemplarily," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application.

[0100] The illustrative expressions of the terms used above do not necessarily refer to the same embodiments or examples. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, those skilled in the art can combine and integrate the different embodiments or examples described herein, as well as the features of those different embodiments or examples, without contradiction.

[0101] Although embodiments of this application have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application. Therefore, any changes or modifications made in accordance with the claims and description of this application should fall within the scope of the patent coverage of this application.

Claims

1. A power transmission device, characterized in that, include: The system includes an engine, generator, drive motor, planetary gear transmission mechanism, synchronizer, brake, first drive shaft, second drive shaft, first and third gear output gears, second gear input gear, and a second gear output gear meshing with the second gear input gear; wherein, The engine is connected to the generator via the first drive shaft, and the engine drives the first drive shaft to realize the generator's power generation function. The planetary gear transmission mechanism includes a gear ring, and planetary gears, a planet carrier, and a sun gear connected within the gear ring; The sun gear and synchronizer are fixedly connected to the first drive shaft; the synchronizer is a double-sided synchronizer, which is located between the planet carrier and the second gear input gear, or the synchronizer includes a first single-sided synchronizer and a second single-sided synchronizer, both of which are connected to the first drive shaft; The first and third gear output gears and the second gear output gear are respectively fixedly connected to the second transmission shaft, and the first and third gear output gears also mesh with the planetary carrier; The drive motor is connected to the second transmission shaft and transmits power to the drive wheels through the second transmission shaft; When the brake is closed, the gear ring is fixedly connected to the first drive shaft and moves with the first drive shaft; When the brake is disengaged, the gear ring moves freely within the first transmission shaft. When the synchronizer is closed, one of the planetary carrier and the second gear input gear is fixed to the first drive shaft, and the other is loosely fitted on the first drive shaft. When the synchronizer is completely disconnected, both the planetary carrier and the second-gear input gear are loosely fitted on the first drive shaft.

2. The power transmission device according to claim 1, characterized in that, The power transmission device further includes a main reduction gear set, a drive motor drive shaft, a drive motor input gear, and a drive motor output gear. The main reduction gear set is driven and connected to the second drive shaft. The drive motor is driven and connected to the drive motor input gear through the drive motor drive shaft. The drive motor input gear meshes with the drive motor output gear. The drive motor output gear is driven and connected to the main reduction gear set.

3. The power transmission device according to claim 2, characterized in that, The output gear of the drive motor is the second-gear output gear.

4. The power transmission device according to claim 2, characterized in that, The power transmission device also includes a third transmission shaft, and the output gear of the drive motor and the main reduction gear set are both fixedly connected to the third transmission shaft.

5. The power transmission device according to claim 4, characterized in that, The main reduction gear set includes a first main reduction input gear, a second main reduction input gear, and a main reduction output gear; wherein... Both the first main reduction input gear and the second main reduction input gear mesh with the main reduction output gear; The first main reduction input gear is fixedly connected to the second transmission shaft; The second main reduction input gear is fixedly connected to the third transmission shaft.

6. The power transmission device according to claim 3, characterized in that, The output gear of the drive motor is fixedly connected to the second transmission shaft.

7. The power transmission device according to claim 1, characterized in that, The power transmission device further includes a generator input gear and a generator output gear. The generator input gear is fixedly connected to the generator drive shaft of the generator, the generator input gear meshes with the generator output gear, and the generator output gear is connected to the first drive shaft.

8. The power transmission device according to any one of claims 1-7, characterized in that, When the planetary carrier on one side of the bilateral synchronizer is closed, the planetary carrier is fixed on the first drive shaft, and the second gear input gear is loosely fitted on the first drive shaft. When the second-gear input gear on the other side of the bilateral synchronizer is closed, the second-gear input gear is fixed on the first drive shaft, and the planetary carrier is mounted on the first drive shaft. When both sides of the bilateral synchronizer are disconnected from the planetary carrier and the second-gear input gear, the planetary carrier and the second-gear input gear are loosely fitted on the first transmission shaft.

9. The power transmission device according to any one of claims 1-7, characterized in that, When the first single-sided synchronizer is closed with the planetary carrier, the planetary carrier is fixedly connected to the first drive shaft; when the first single-sided synchronizer is disconnected from the planetary carrier, the planetary carrier is loosely fitted onto the first drive shaft. When the second single-sided synchronizer is engaged with the second-gear input gear, the second-gear input gear is fixedly connected to the first drive shaft; When the second single-sided synchronizer is disconnected from the second gear input gear, the second gear input gear is loosely fitted on the first drive shaft.

10. A hybrid electric vehicle, characterized in that, It includes a drive wheel and a power transmission device as described in any one of claims 1-9, wherein the power transmission device is used to drive the drive wheel.

11. A control method for a hybrid electric vehicle, characterized in that, The control method is used to control the hybrid electric vehicle as described in claim 10; wherein, the control method enables the hybrid electric vehicle to switch between pure electric mode, range-extended mode, engine direct drive mode and hybrid mode by controlling the opening and closing of the brake and the synchronizer.

12. The control method for a hybrid electric vehicle according to claim 11, characterized in that, The hybrid vehicle switching to pure electric mode includes: The brake is disengaged and the synchronizer is fully disengaged to transmit power from the drive motor to the second drive shaft, and then to the drive wheels via the second drive shaft.

13. The control method for a hybrid electric vehicle according to claim 11, characterized in that, The switching of the hybrid vehicle to range-extended mode includes: The brake is disengaged and the synchronizer is fully disengaged to transmit the engine's power to the generator via the first drive shaft, thereby achieving idle-speed power generation. The drive motor is started, and its power is transmitted to the second drive shaft, which then transmits the power to the drive wheels.

14. The control method for a hybrid electric vehicle according to claim 11, characterized in that, The hybrid vehicle switches to engine direct drive mode, including a first-gear engine direct drive mode, a second-gear engine direct drive mode, and a third-gear engine direct drive mode; wherein, The hybrid vehicle switching to the engine direct drive mode of the first gear includes: The brake is closed and the synchronizer is fully disengaged, so that the power of the engine is transmitted sequentially through the first drive shaft and the first and third gear output gears to the second drive shaft, and then transmitted to the drive wheels through the second drive shaft. The hybrid vehicle switches to the second gear engine direct drive mode, including: The brake is disengaged, and the synchronizer is engaged with the second-gear output gear, so that the engine power is transmitted sequentially through the first drive shaft, the second-gear input gear, and the second-gear output gear to the second drive shaft, and then transmitted to the drive wheels through the second drive shaft. The hybrid vehicle switching to the third gear engine direct drive mode includes: The brake is disengaged, and the synchronizer is engaged with the first and third gear output gears, so that the power of the engine is transmitted sequentially through the first drive shaft, the planetary carrier, and the first and third gear output gears to the second drive shaft, and then transmitted to the drive wheels through the second drive shaft.

15. The control method for a hybrid electric vehicle according to claim 14, characterized in that, The hybrid vehicle switches to hybrid drive mode including a first-gear hybrid drive mode, a second-gear hybrid drive mode, and a third-gear hybrid drive mode; wherein, The hybrid vehicle switching to the first gear hybrid drive mode includes: When the hybrid vehicle switches to the engine direct drive mode of the first gear, the drive motor is started and the power of the drive motor is transmitted to the second drive shaft, and the power is transmitted to the drive wheels through the second drive shaft; The hybrid vehicle switches to the second-gear hybrid drive mode, including: When the hybrid vehicle switches to the engine direct drive mode of the second gear, the drive motor is started and the power of the drive motor is transmitted to the second drive shaft, and the power is transmitted to the drive wheels through the second drive shaft; The hybrid vehicle switches to the third-gear hybrid drive mode, including: When the hybrid vehicle switches to the third gear engine direct drive mode, the drive motor is started and the power of the drive motor is transmitted to the second drive shaft, and the power is transmitted to the drive wheels through the second drive shaft.

Images