Longitudinal four-wheel drive hybrid system and control method, and vehicle

Abstract

The application provides a longitudinal four-wheel drive hybrid system and a control method and a vehicle, and relates to the technical field of new energy vehicles.The longitudinal four-wheel drive hybrid system comprises an engine, a shock absorber, a power battery and a driving assembly.The driving assembly comprises a double-motor controller, a first motor driving component, a second motor driving component, a transmission component, a front driving axle and a rear driving axle.The transmission component comprises a power input shaft, a first output shaft and a first dog tooth coupling mechanism.The output end of the first motor driving component is in a constant connection state with the power input shaft.The second motor driving component comprises a second motor and a second dog tooth coupling mechanism.The front driving axle comprises a second output shaft, a torque limiter and a front axle differential assembly.The torque limiter is arranged on the second output shaft.The rear driving axle is connected with the first output shaft through a transmission shaft.The application has high structural integration, compact layout, can realize power cross shaft scheduling and has strong escape ability.

Description

Technical Field

[0001] This invention relates to the field of new energy vehicle technology, and in particular to a longitudinally mounted four-wheel drive hybrid system and control method, and a vehicle. Background Technology

[0002] As the automotive industry shifts towards energy conservation, environmental protection, and high performance, hybrid drive systems, especially longitudinally mounted four-wheel drive hybrid systems, have become a core research and development direction in the passenger and commercial vehicle sectors because they can simultaneously balance power output, off-road capability, and fuel economy.

[0003] Currently, the mainstream longitudinal four-wheel drive hybrid systems in the industry mainly fall into two categories: The first type adopts a three-motor architecture consisting of a high-power drive motor on the front axle, a generator, and a high-power motor on the rear axle. The front and rear axles are independent power units without mechanical connection. In application, this solution suffers from structural defects in cross-axle power dispatching. When the vehicle is in a difficult situation where only one axle has traction, power cannot be dispatched across axles, and the ability to get out of trouble relies entirely on the power and torque of a single motor, resulting in insufficient power performance. The second type of solution mainly consists of dispersed components such as dual electronic controls, engine, drive motor, transmission, drive shaft, drive axle, and half-shaft. The power transmission path is "longitudinal engine → hybrid transmission → drive motor → drive shaft → drive axle → half-shaft → front wheel". The power transmission link is long and the components are scattered, resulting in low system integration, significant energy loss in the transmission process, and poor transmission efficiency. In addition, to achieve four-wheel drive, an additional independent rear-wheel drive assembly (including a single electronic control unit, drive motor, reducer, and other core components) is required, further increasing costs and layout complexity. Moreover, it cannot reserve sufficient installation space for the power battery, making it difficult to adapt to the upgrade requirements of plug-in hybrid vehicles.

[0004] In summary, existing longitudinal four-wheel drive hybrid systems generally suffer from common problems such as complex structure, low integration, high cost, lack of cross-axle power dispatching, poor energy efficiency, and poor platform adaptability. They are unable to meet the comprehensive needs of vehicles for compact layout, cost control, extreme mode performance, and multi-model expansion. Therefore, there is an urgent need to develop a new type of longitudinal four-wheel drive hybrid system. Summary of the Invention

[0005] Based on this, the purpose of the present invention is to provide a longitudinally mounted four-wheel drive hybrid system and control method, as well as a vehicle, in order to solve at least one of the technical problems mentioned in the background art.

[0006] One aspect of the present invention is to provide a longitudinally mounted four-wheel drive hybrid system, including an engine, a shock absorber, a power battery and a drive assembly, wherein the engine is arranged longitudinally along the vehicle and is connected to the drive assembly through the shock absorber to transmit mechanical work and dampen vibration;

[0007] The drive assembly includes a dual-motor controller, a first motor drive assembly, a second motor drive assembly, a transmission assembly, a front drive axle, and a rear drive axle;

[0008] The transmission assembly includes a power input shaft, a first output shaft, and a first dog gear engagement mechanism. The first dog gear engagement mechanism is used to selectively transmit the power of the engine to the first output shaft at different speed ratios. The first output shaft is used to simultaneously distribute power to the front drive axle and the rear drive axle.

[0009] The output end of the first motor drive component is always connected to the power input shaft.

[0010] The second motor drive assembly includes a second motor and a second dog-tooth engagement mechanism, the second dog-tooth engagement mechanism being used to selectively transmit the power of the second motor to the first output shaft at different speed ratios;

[0011] The front drive axle includes a second output shaft, a torque limiter, and a front axle differential assembly. The torque limiter is disposed on the second output shaft and is used to limit the torque transmitted to the front drive axle.

[0012] The rear drive axle is connected to the first output shaft via the drive shaft, and the rear drive axle includes a clutch and a rear axle differential assembly to achieve four-wheel drive.

[0013] In addition, the longitudinally mounted four-wheel drive hybrid system according to the present invention may also have the following additional technical features:

[0014] Furthermore, the transmission assembly is a two-speed transmission assembly, with a first-speed drive gear and a second-speed drive gear on the power input shaft, and a first-speed driven gear and a second-speed driven gear on the first output shaft respectively meshing with the first-speed drive gear and the second-speed drive gear.

[0015] Furthermore, the first dog-tooth engagement mechanism is disposed on the first output shaft and is used to selectively engage the first gear driven gear or the second gear driven gear of the transmission.

[0016] Furthermore, the torque limiter is an end-face dog-tooth clutch structure, and the torque limiter includes locking teeth and a spring. The locking teeth are connected to the second output shaft via splines.

[0017] Furthermore, the first motor drive assembly includes a first motor, a first motor input shaft, a first motor input gear, a first motor idler gear, and a first motor output gear;

[0018] The first motor output gear is coaxially fixed on the power input shaft and is constantly meshed with the first motor input gear through the first motor idler gear, so that the first motor and the engine are always connected, which is used to selectively start the engine or recover the excess torque of the engine to generate electricity.

[0019] Furthermore, the second motor drive assembly also includes a second motor input shaft and a second motor intermediate shaft. The second motor input shaft is provided with a second motor input gear, and the second motor intermediate shaft is provided with a second motor output gear, a second motor first gear drive gear, and a second motor second gear drive gear. The second motor output gear meshes with the second motor input gear.

[0020] The first output shaft is provided with a second motor first gear driven gear and a second motor second gear driven gear that mesh with the second motor first gear drive gear and the second motor second gear drive gear, respectively;

[0021] The second dog-tooth engagement mechanism is located on the first output shaft and is used to selectively engage the first gear driven gear or the second gear driven gear of the second motor.

[0022] Furthermore, the engine, the first motor, and the second motor are arranged with parallel axes.

[0023] Furthermore, the dual-motor controller is electrically connected to the power battery via the vehicle's high-voltage wiring harness.

[0024] Another aspect of the present invention is to provide a control method for a longitudinally mounted four-wheel drive hybrid system, for controlling the aforementioned longitudinally mounted four-wheel drive hybrid system, comprising the following steps:

[0025] Obtain vehicle status parameters, which include one or more of the following: vehicle speed, engine torque, battery charge, vehicle required torque, motor drive efficiency, and engine drive efficiency.

[0026] Based on the state parameters, the engagement states of the first dog-tooth engagement mechanism, the second dog-tooth engagement mechanism, and the clutch are controlled, so that the longitudinal four-wheel drive hybrid system switches between pure electric drive mode, engine direct drive mode, and series drive mode.

[0027] Another aspect of the present invention is to provide a vehicle comprising the above-described longitudinal four-wheel drive hybrid system.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows: The present application has a high degree of structural integration and a compact layout. Specifically, through the integrated design of the drive assembly, the dual motor controller, dual motor drive components, transmission components and front and rear drive axles are integrated into one unit, replacing the traditional distributed layout, shortening the power transmission path, reducing energy loss, and reserving sufficient installation space for the power battery, adapting to the upgrade needs of plug-in hybrid vehicles; furthermore, the present application can realize cross-axle power scheduling and has strong off-road capability. Specifically, the mechanical connection between the front drive axle and the rear drive axle is realized through the drive shaft, breaking the limitations of traditional independent axle drive. When a single axle is not attached, the power can be transmitted to the attached axle through the drive shaft, significantly improving the vehicle's off-road capability;

[0029] Furthermore, this application enables multi-mode coordination to ensure optimal efficiency. Specifically, through the coordinated design of a two-speed transmission and dual motors, it achieves switching between multiple modes, including pure electric drive, engine direct drive, series drive, parallel drive, and four-wheel drive. It can automatically match the optimal mode based on parameters such as vehicle speed, battery charge, and required torque, ensuring that the engine and motor always operate in the high-efficiency range, improving fuel economy and power performance. In addition, this application also uses a first and second dog-tooth engagement mechanism to achieve speed ratio switching and power engagement, which is simple in structure, responds quickly, and has high reliability, and is less expensive than the synchronizer structure. It also includes a torque limiter to effectively protect the transmission system from overload damage and extend the service life of components. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the longitudinal four-wheel drive hybrid system in the first embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of the longitudinal four-wheel drive hybrid system in the second embodiment of the present invention;

[0032] Figure 3 This is a schematic diagram of the longitudinal four-wheel drive hybrid system in the third embodiment of the present invention;

[0033] Figure 4 This is a power transmission path diagram of the longitudinally mounted four-wheel drive hybrid system in the first embodiment of the present invention when starting the engine;

[0034] Figure 5 This is a power transmission path diagram of the longitudinal four-wheel drive hybrid system in the first embodiment of the present invention when it is in parking charging mode;

[0035] Figure 6 This is a power transmission path diagram of the longitudinal four-wheel drive hybrid system in the first embodiment of the present invention when it is in pure electric drive mode;

[0036] Figure 7This is a power transmission path diagram of the longitudinal four-wheel drive hybrid system in the first embodiment of the present invention when it is in braking energy recovery mode;

[0037] Figure 8 This is a power transmission path diagram of the longitudinally mounted four-wheel drive hybrid system in the first embodiment of the present invention when the engine is in first gear and driving independently.

[0038] Figure 9 This is a power transmission path diagram of the longitudinally mounted four-wheel drive hybrid system in the first embodiment of the present invention when the engine is in second gear independent drive.

[0039] Figure 10 This is a power transmission path diagram of the longitudinal four-wheel drive hybrid system in the series drive mode in the first embodiment of the present invention;

[0040] Figure 11 This is a power transmission path diagram of the longitudinally mounted four-wheel drive hybrid system in the first embodiment of the present invention when the engine is in first gear and the first motor is generating electricity.

[0041] Figure 12 This is a power transmission path diagram of the longitudinally mounted four-wheel drive hybrid system in the first embodiment of the present invention when the engine is in second gear and the first motor is generating electricity.

[0042] Figure 13 This is a power transmission path diagram of the longitudinal four-wheel drive hybrid system in the first embodiment of the present invention when the engine is driven in first gear and the second motor is driven in parallel.

[0043] Figure 14 This is a power transmission path diagram of the longitudinal four-wheel drive hybrid system in the first embodiment of the present invention when the engine is driven in second gear and the second motor is driven in parallel.

[0044] Figure 15 This is a power transmission path diagram of the longitudinal four-wheel drive hybrid system in the four-wheel drive mode in the first embodiment of the present invention;

[0045] Figure 16 This is a schematic diagram of the torque limiter in the longitudinal four-wheel drive hybrid system of the first embodiment of the present invention.

[0046] The above-mentioned figures include the following reference numerals: 10-engine; 20-shock absorber; 30-dual motor controller; 31-first motor high-voltage connector; 32-second motor high-voltage connector; 33-vehicle high-voltage wiring harness; 40-first motor; 41-first motor input shaft; 42-first motor input gear; 43-first motor idler gear; 44-first motor output gear; 45-power input shaft; 46-second gear drive gear of transmission; 47-first gear drive gear of transmission; 48-first output shaft; 49-second gear driven gear of transmission; 50-first dog-tooth engagement mechanism; 51-first gear driven gear of transmission; 52-front axle drive gear; 53-front axle driven gear; 54-second output shaft; 55-front axle hypoid drive gear; 56-Front axle differential assembly; 57-Front axle hypoid driven gear; 58-Drive shaft; 59-Torque limiter; 591-Locking gear; 592-Spring; 60-Second motor; 61-Second motor input shaft; 62-Second motor input gear; 63-Second motor output gear; 64-Second motor first gear drive gear; 65-Second motor intermediate shaft; 66-Second motor second gear drive gear; 67-Second motor second gear driven gear; 68-Second dog-tooth engagement mechanism; 69-Second motor first gear driven gear; 70-Power battery; 71-Clutch; 72-Fourth output shaft; 73-Rear axle differential assembly; 81-Rear axle drive gear; 82-Rear axle driven gear; 83-Third output shaft; 110-Half shaft; 120-Wheel.

[0047] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0048] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Several embodiments of the invention are illustrated in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

[0049] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0051] Example 1

[0052] Please see Figure 1 , Figures 4 to 16 The image shows a longitudinally mounted four-wheel drive hybrid system according to a first embodiment of the present invention, comprising: an engine 10, a shock absorber 20, a power battery 70, a drive assembly, a drive shaft 58, a half shaft 110, and wheels 120. The engine 10 is arranged longitudinally along the vehicle, with its axis set at 90° to the drive axis of the front wheels. The engine 10 is connected to the drive assembly through the shock absorber 20. The shock absorber 20 adopts a rubber damping structure, which can effectively absorb the vibration generated by the engine 10 during operation, prevent the vibration from being transmitted to other components of the drive assembly, reduce component wear, and improve the system's operational stability.

[0053] The drivetrain is an integrated structure, specifically including a dual-motor controller 30, a first motor drive assembly, a second motor drive assembly, a transmission assembly, a front drive axle, and a rear drive axle. This replaces the traditional distributed layout, significantly shortening the power transmission path, reducing energy transfer losses, and simplifying component placement, while also providing ample installation space for the power battery 70. The dual-motor controller 30 is electrically connected to the power battery 70 via the vehicle's high-voltage wiring harness 33, enabling stable power transmission and distribution. The dual-motor controller 30 is connected to the first motor drive assembly via the first motor high-voltage connector 31 to transfer power to the first motor drive assembly. The dual-motor controller 30 is also connected to the second motor drive assembly via the second motor high-voltage connector 32 to transfer power to the second motor drive assembly. The dual-motor controller 30 incorporates a dual-motor control algorithm, allowing independent control of the operating status of the first motor 40 and the second motor 60, and precise adjustment of motor speed, torque, and switching of operating modes.

[0054] The transmission assembly includes a power input shaft 45, a first output shaft 48, and a first dog-tooth engagement mechanism 50. The first dog-tooth engagement mechanism 50 is used to selectively transmit the power of the engine 10 to the first output shaft 48 at different speed ratios. The first output shaft 48 is used to simultaneously distribute power to the front drive axle and the rear drive axle. In this embodiment, the transmission assembly is a two-speed transmission assembly. A first-speed drive gear 47 and a second-speed drive gear 46 are coaxially fixed on the power input shaft 45. The first-speed drive gear 47 is located between the first motor output gear 44 and the second-speed drive gear 46. The first-speed drive gear 47 has more teeth than the second-speed drive gear 46, achieving different speed ratios. Correspondingly, a second-gear driven gear 49 and a first-gear driven gear 51 are sequentially loosely fitted along the axis of the first output shaft 48. The second-gear driven gear 49 and the first-gear driven gear 51 mesh with the second-gear drive gear 46 and the first-gear drive gear 47, respectively. A first dog-tooth engagement mechanism 50 is coaxially fixed on the first output shaft 48 between the second-gear driven gear 49 and the first-gear driven gear 51. The first dog-tooth engagement mechanism 50 selectively engages either the first-gear driven gear 51 or the second-gear driven gear 49, switching between the two gear ratios to adapt to the operating requirements of the engine 10 under different conditions such as low-speed high torque and high-speed efficient cruising, ensuring that the engine 10 is always in its efficient operating range. In this embodiment, the first dog-tooth engagement mechanism 50 adopts a sliding tooth sleeve structure. The axial movement of the sliding tooth sleeve is controlled by a shift fork to achieve engagement with either the first-gear driven gear 51 or the second-gear driven gear 49, thereby switching the gear ratio. The engagement response time is short, and the transmission efficiency is high.

[0055] The output end of the first motor drive assembly is always connected to the power input shaft 45, so that the first motor 40 and the engine 10 are always connected, which can be used to selectively start the engine 10 or recover the excess torque of the engine 10 to generate electricity. Specifically, the first motor drive assembly includes a first motor 40, a first motor input shaft 41, a first motor input gear 42, a first motor idler gear 43, and a first motor output gear 44. The first motor 40 is connected to the dual motor controller 30 via a first motor high-voltage connector 31. The first motor input gear 42 is coaxially fixed on the first motor input shaft 41, and the first motor output gear 44 is coaxially fixed on the power input shaft 45. The first motor output gear 44 is constantly meshed with the first motor input gear 42 via the first motor idler gear 43. This meshing structure ensures that the first motor 40 and the engine 10 always maintain a power linkage state. This structural design gives the first motor 40 a dual function: first, it can selectively start the engine 10 without the need for an additional starter, simplifying the system structure; second, it can recover the excess torque of the engine 10 to generate electricity, converting mechanical energy into electrical energy and storing it in the power battery 70, thereby improving energy utilization.

[0056] The second motor drive assembly includes a second motor 60, a second motor input shaft 61, a second motor input gear 62, a second motor intermediate shaft 65, a second motor first gear drive gear 64, a second motor second gear drive gear 66, a second motor first gear driven gear 69, a second dog-tooth engagement mechanism 68, and a second motor second gear driven gear 67. The second motor 60 is connected to the dual motor controller 30 via a second motor high-voltage connector 32. The second motor input gear 62 is coaxially fixed on the second motor input shaft 61. The second motor second gear drive gear 66, the second motor first gear drive gear 64, and the second motor output gear 63 are coaxially fixed along the axis of the second motor intermediate shaft 65. The second motor output gear 63 is constantly meshed with the second motor input gear 62 to form a stable power transmission link.

[0057] A second motor second-gear driven gear 67 and a second motor first-gear driven gear 69 are sequentially loosely fitted along the axis of the first output shaft 48. The second motor second-gear driven gear 67 and the second motor first-gear driven gear 69 mesh with the second motor second-gear drive gear 66 and the second motor first-gear drive gear 64, respectively. A front axle drive gear 52 is coaxially fixed on the first output shaft 48 located between the transmission first-gear driven gear 51 and the second motor second-gear driven gear 67. A second dog-tooth engagement mechanism 68 is coaxially fixed on the first output shaft 48 located between the second motor second-gear driven gear 67 and the second motor first-gear driven gear 69. The second dog-tooth engagement mechanism 68 is used to selectively engage the second motor first-gear driven gear 69 or the second motor second-gear driven gear 67. It can switch the output speed ratio of the second motor 60 according to the vehicle driving conditions (such as low-speed climbing and high-speed cruising) to ensure that the second motor 60 can maintain efficient operation in different speed ranges. In this embodiment, the second dog tooth engagement mechanism 68 has the same structure as the first dog tooth engagement mechanism 50. The sliding tooth sleeve is engaged with different driven gears by the shift fork to realize the speed ratio switching of the second motor 60.

[0058] The front drive axle includes a second output shaft 54, a front axle driven gear 53, a torque limiter 59, a front axle hypoid drive gear 55, a front axle hypoid driven gear 57, and a front axle differential assembly 56. The overall power transmission path is as follows: power input → front axle drive gear 52 → front axle driven gear 53 → torque limiter 59 → second output shaft 54 ​​→ front axle hypoid drive gear 55 → front axle hypoid driven gear 57 → front axle differential assembly 56 → half shaft 110 → left and right front wheels 120. Specifically, a front axle hypoid drive gear 55 is fixedly mounted at the front end of the second output shaft 54. A front axle hypoid driven gear 57 and a front axle differential assembly 56 are sequentially loosely fitted on the half-shaft 110 between the two front wheels of the vehicle along its axis. The front axle hypoid drive gear 55 meshes with the front axle hypoid driven gear 57. This meshing structure can not only reduce speed and increase torque, but also convert the longitudinal power along the second output shaft 54 ​​into the lateral power driving the front axle differential assembly 56. Moreover, the overall axis of the second output shaft 54 ​​is perpendicular to the rotation axis of the front axle differential assembly 56, which is adapted to the spatial layout of the hypoid gear to achieve a 90° change in power direction and ensure that the power is accurately transmitted to the front wheels.

[0059] The middle section of the second output shaft 54 ​​is sequentially fitted with a front axle driven gear 53 and a torque limiter 59 along its axis. The front axle driven gear 53 meshes with the front axle drive gear 52, and the torque limiter 59 engages with the front axle driven gear 53 to limit the torque transmitted to the front drive axle. In this embodiment, the torque limiter 59 is a face dog-tooth clutch structure, including locking teeth 591 and a spring 592 for providing preload. The front axle driven gear 53 is loosely fitted on the second output shaft 54, and the locking teeth 591 are connected to the second output shaft 54 ​​via splines. The opposite end faces of the front axle driven gear 53 and the locking teeth 591 are provided with meshing engagement teeth. The spring 592 provides a continuous preload to the locking teeth 591, keeping the engagement teeth in normal mesh, thereby limiting the maximum transmitted torque to protect the transmission mechanism.

[0060] The working principle of the torque limiter 59 is as follows: Under normal operating conditions (transmitted torque ≤ gear design limit), power is input from the front axle drive gear 52, which drives the front axle driven gear 53 meshing with it to rotate. The front axle driven gear 53 drives the torque limiter 59 to rotate synchronously. Due to the preload of the spring 592, the front axle driven gear 53 and the locking gear 591 mesh tightly. Power is transmitted to the locking gear 591 through the engagement teeth. The locking gear 591 drives the second output shaft 54 ​​to rotate through the spline, thereby driving the front axle hypoid drive gear 55. After the front axle hypoid drive gear 55 meshes with the front axle hypoid driven gear 57, the power is transmitted to the front axle differential assembly 56 through the differential housing, and then distributed to the left and right half shafts 110 through the front axle differential assembly 56, ultimately driving the left and right front wheels to rotate. When turning, the differential automatically adjusts the speed of the left and right half shafts 110 to achieve differential wheel travel and avoid wheel slippage. When an overload condition occurs (transmitted torque > gear bearing limit), i.e., increased road resistance (such as climbing, getting stuck) or sudden impact load, the excessive torque will cause the front axle driven gear 53 and locking tooth 591 to generate an axial thrust greater than the preload of spring 592, causing the meshing teeth of the two to slip relative to each other (the end face dog teeth disengage from the fully meshed state). During the sliding of the meshing teeth, locking tooth 591 is pushed away from the front axle driven gear 53 and compresses the preload spring 592. At this time, the power transmission is partially cut off or restricted (the torque cannot continue to increase), avoiding damage such as gear tooth breakage and shaft deformation. When the load decreases (such as reduced road resistance) and the transmitted torque falls below the limit, the preload of spring 592 is greater than the axial thrust between the meshing teeth. Spring 592 pushes locking tooth 591 to reset, so that the meshing teeth of front axle driven gear 53 and locking tooth 591 re-engage completely, the power transmission returns to normal, and the second output shaft 54 ​​continues to drive the subsequent components to drive the wheels.

[0061] The rear drive axle is connected to the first output shaft 48 via a drive shaft 58, forming a mechanical linkage that solves the problem of lack of cross-axle power dispatching in traditional solutions. Specifically, the rear drive axle includes a clutch 71, a fourth output shaft 72, and a rear axle differential assembly 73. The clutch 71 controls the engagement and disengagement of the rear drive axle, enabling flexible switching between two-wheel drive and four-wheel drive modes. The rear axle differential assembly 73 adjusts the speed difference between the left and right rear wheels 120, ensuring vehicle stability during steering and driving on complex road surfaces. The clutch 71 and a rear axle hypoid drive gear (not shown in the figure) are coaxially fixed along the axis of the fourth output shaft 72. The rear axle differential assembly 73 and a rear axle hypoid driven gear (not shown in the figure) are loosely fitted onto the half-shaft 110 between the two rear wheels of the vehicle. The rear axle hypoid driven gear meshes with the rear axle hypoid drive gear, and the rotation axes of the fourth output shaft 72 and the rear axle differential assembly 73 are perpendicular to each other, realizing power direction conversion and deceleration and torque increase. Furthermore, in this embodiment, a rear axle transmission assembly is provided between the rear drive axle and the front drive axle. The rear axle transmission assembly includes a rear axle drive gear 81, a rear axle driven gear 82, and a third output shaft 83. The rear axle drive gear 81 is coaxially fixed at the rear end of the first output shaft 48. The third output shaft 83 is located behind the second output shaft 54 ​​and its axis coincides with that of the second output shaft 54. The rear axle driven gear 82 is coaxially fixed at the front end of the third output shaft 83. The rear end of the third output shaft 83 is connected to the front end of the fourth output shaft 72 through a transmission shaft 58. This transmission structure ensures that the power of the first output shaft 48 can be stably transmitted to the rear drive axle, providing a power foundation for the four-wheel drive mode.

[0062] Furthermore, the engine 10, the first motor 40, and the second motor 60 are arranged with parallel axes. Specifically, the first motor input shaft 41, the second motor input shaft 61, the power input shaft 45, the first output shaft 48, the second output shaft 54, and the fourth output shaft 72 are all arranged in parallel. The rear end of the power input shaft 45 is provided with the second motor intermediate shaft 65, and the axis of the second motor intermediate shaft 65 coincides with the axis of the power input shaft 45. The rear end of the second output shaft 54 ​​is provided with the third output shaft 83, and the axis of the third output shaft 83 coincides with the axis of the second output shaft 54. This layout makes the components compact, reduces the lateral space occupied by the system, and reduces the directional conversion loss during power transmission, thereby improving transmission efficiency.

[0063] The power transmission path of the longitudinally mounted four-wheel drive hybrid system in this application includes the following operating conditions:

[0064] like Figure 4As shown, the power transmission path of the longitudinally mounted four-wheel drive hybrid system of this application when starting the engine is as follows: electrical power passes through the power battery 70 → vehicle high-voltage wiring harness 33 → dual-motor controller 30 → first motor high-voltage connector 31 → first motor 40 → first motor input shaft 41 → first motor input gear 42 → first motor idler gear 43 → first motor output gear 44 → power input shaft 45 → shock absorber 20 → engine 10. The electrical energy generated by the first motor 40 is converted into mechanical energy through gear meshing to start the engine 10. During the starting process, the dual-motor controller 30 controls the first motor 40 to output appropriate speed and torque to ensure a smooth start for the engine 10. Simultaneously, the first motor input gear 42 is constantly connected to the first motor output gear 44 through the first motor idler gear 43, ensuring that the first motor 40 and engine 10 remain constantly connected. By controlling the first motor 40, the engine 10 can be started at any time without the need for an additional starter, simplifying the system structure.

[0065] like Figure 5 As shown, when the longitudinally mounted four-wheel drive hybrid system of this application is charging while parked, its power transmission path is the same as... Figure 4 In contrast, specifically: the power transmission path is the opposite of the engine start-up condition: after the engine 10 starts, the mechanical energy is transmitted through the shock absorber 20 → power input shaft 45 → first motor output gear 44 → first motor idler gear 43 → first motor input gear 42 → first motor input shaft 41 → first motor 40. The first motor 40 switches to power generation mode, converting mechanical energy into electrical energy, and then through the first motor high-voltage connector 31 → dual motor controller 30 → vehicle high-voltage wiring harness 33 → power battery 70 to realize the parking charging function, which is suitable for the scenario of replenishing energy when the battery power is insufficient.

[0066] like Figure 6 As shown, when the longitudinally mounted four-wheel drive hybrid system of this application is in pure electric drive mode, its power transmission path is as follows: electric power passes through the power battery 70 → vehicle high-voltage wiring harness 33 → dual motor controller 30 → second motor high-voltage connector 32 → second motor 60 → second motor input shaft 61 → second motor input gear 62 → second motor output gear 63 → second motor intermediate shaft 65 → second motor second gear drive gear 66 → second motor second gear driven gear 67 → second dog-tooth engagement mechanism 68 → first output shaft 48 → front axle drive gear 52 → front axle driven gear 53 → torque limiter 59 → second output shaft 54 ​​→ front axle quasi-hyperboloid drive gear 55 → front axle quasi-hyperboloid driven gear 57 → front axle differential assembly 56 → half shaft 110 → two front wheels 120 on the left and right sides; at this time, the engine 10 is turned off, the first dog-tooth engagement mechanism 50 is disengaged, and the second motor 60 drives the vehicle independently, achieving zero-emission driving, which is suitable for urban low-speed commuting scenarios.

[0067] like Figure 7As shown, when the longitudinally mounted four-wheel drive hybrid system of this application is in regenerative braking mode, its power transmission path is... Figure 6 The reverse transmission of pure electric drive mode: When the vehicle brakes, the wheel 120 drives the half shaft 110 through inertia → front axle differential assembly 56 → front axle hypoid driven gear 57 → front axle hypoid drive gear 55 → second output shaft 54 ​​→ torque limiter 59 → front axle driven gear 53 → front axle drive gear 52 → first output shaft 48 → second dog tooth engagement mechanism 68 → second motor second gear driven gear 67 → second motor second gear drive gear 66 → second motor intermediate shaft 65 → second motor output gear 63 → second motor input gear 62 → second motor input shaft 61 → second motor 60. The second motor 60 switches to power generation mode, converting the mechanical energy during braking into electrical energy, and then through the second motor high voltage connector 32 → dual motor controller 30 → vehicle high voltage wiring harness 33 → power battery 70 to realize braking energy recovery and improve driving range; there is no gear shifting action in this mode, and the recovery efficiency is stable.

[0068] like Figure 8 As shown, when the longitudinally mounted four-wheel drive hybrid system of this application is in first gear independent drive, its power transmission path is as follows: mechanical power passes through engine 10 → shock absorber 20 → power input shaft 45 → first gear drive gear 47 of transmission → first gear driven gear 51 of transmission → first dog gear engagement mechanism 50 → first output shaft 48 → front axle drive gear 52 → front axle driven gear 53 → torque limiter 59 → second output shaft 54 ​​→ front axle hypoid drive gear 55 → front axle hypoid driven gear 57 → front axle differential assembly 56 → half shaft 110 → two front wheels 120 on the left and right sides; at this time, the first dog gear engagement mechanism 50 engages with the first gear driven gear 51 of transmission, the second dog gear engagement mechanism 68 disengages, the first motor 40 and the second motor 60 are in a free state, and the engine 10 outputs high torque through the first gear ratio, which is suitable for low-speed climbing and heavy load scenarios.

[0069] like Figure 9 As shown, when the longitudinally mounted four-wheel drive hybrid system of this application is in second-gear independent drive mode, its power transmission path is the same as... Figure 8 The difference between the engine's independent first-gear drive and the transmission's second-gear driven gear 49 is that the first dog-tooth engagement mechanism 50 engages with the transmission's second-gear driven gear 49. Specifically: mechanical power is transmitted through the engine 10 → shock absorber 20 → power input shaft 45 → transmission's second-gear drive gear 46 → transmission's second-gear driven gear 49 → first dog-tooth engagement mechanism 50 → first output shaft 48 → front axle drive gear 52 → front axle driven gear 53 → torque limiter 59 → second output shaft 54 ​​→ front axle hypoid drive gear 55 → front axle hypoid driven gear 57 → front axle differential assembly 56 → half shaft 110 → two front wheels 120. The second-gear ratio is suitable for medium- and high-speed cruising scenarios, with the engine 10 operating in its efficient speed range, improving fuel economy.

[0070] like Figure 10 As shown, in series drive mode, the power transmission path of the longitudinal four-wheel drive hybrid system of this application is as follows: engine 10 → shock absorber 20 → power input shaft 45 → first motor output gear 44 → first motor idler gear 43 → first motor input gear 42 → first motor input shaft 41 → first motor 40. The first motor 40 converts mechanical energy into electrical energy for further transmission. First motor 40 → first motor high-voltage connector 31 → dual motor controller 30. The dual motor controller 30 determines whether energy needs to be obtained from or replenished from the power battery 70 based on the wheel-side power demand. Then, dual motor controller 30 → second motor high-voltage connector 32 → second motor 60. The second motor 60 converts electrical energy into mechanical energy for further transmission. Second motor 60 → second motor 7 ... Motor input shaft 61 → Second motor input gear 62 → Second motor output gear 63 → Second motor intermediate shaft 65 → Second motor second gear drive gear 66 → Second motor second gear driven gear 67 → Second dog tooth engagement mechanism 68 → First output shaft 48 → Front axle drive gear 52 → Front axle driven gear 53 → Torque limiter 59 → Second output shaft 54 ​​→ Front axle quasi-hypoid drive gear 55 → Front axle quasi-hypoid driven gear 57 → Front axle differential assembly 56 → Half shaft 110 → Two front wheels 120; The series drive achieves decoupling between the engine 10 and the wheel-side drive power through two energy conversions: mechanical energy → electrical energy → mechanical energy, ensuring that the engine 10 always operates in the high-efficiency range, suitable for scenarios with low battery power and low-speed driving.

[0071] like Figure 11As shown, in the longitudinal four-wheel drive hybrid system of this application, when the engine is in first gear and the first motor is generating electricity, the power transmission path is as follows: mechanical power passes through engine 10 → shock absorber 20 → power input shaft 45 → first motor output gear 44. Since the power of engine 10 is higher than the power demand at the wheel end, a portion of the power is split at the power input shaft 45, forming two power transmission paths. Specifically, the first path is the wheel end drive path: power input shaft 45 → first gear drive gear 47 of the transmission → first gear driven gear 51 of the transmission → first dog tooth engagement mechanism 50 → first output shaft 48 → front axle drive gear 52 → front axle driven gear 53 → torque limiter 59 → second output shaft 54 ​​→ front axle quasi-hyperboloid drive gear 55 → front axle quasi-hyperboloid driven gear 57 → front axle differential assembly 56 → half shaft 110 → two front wheels 120. The second path is the charging path: First motor output gear 44 → First motor idler gear 43 → First motor input gear 42 → First motor input shaft 41 → First motor 40. The first motor 40 converts mechanical energy into electrical energy for further transmission. First motor 40 → First motor high-voltage connector 31 → Dual motor controller 30 → Vehicle high-voltage wiring harness 33 → Power battery 70. This mode is suitable for scenarios where the engine 10 has a high efficiency range and the wheel end torque requirement is relatively small. It can recover excess energy and improve energy utilization.

[0072] like Figure 12 As shown, in the longitudinally mounted four-wheel drive hybrid system of this application, when the engine is in second gear and the first motor is generating electricity, its power transmission path is the same as... Figure 11 The difference between the power transmission path in this system and the one driven by the engine in first gear and the one generated by the first motor is that the first dog-tooth engagement mechanism 50 engages with the second gear driven gear 49 of the transmission, while the rest of the transmission path is the same. This system is suitable for high-speed cruising and scenarios where the engine 10 has a lot of spare power. It can meet the vehicle's driving needs while charging the power battery 70.

[0073] like Figure 13As shown, when the longitudinally mounted four-wheel drive hybrid system of this application is driven by the engine in first gear and the second motor is driven in parallel, its power transmission path is two, which finally converges on the first output shaft 48. Specifically, the first path is the transmission of mechanical energy from the engine: engine 10 → shock absorber 20 → power input shaft 45 → transmission first gear drive gear 47 → transmission first gear driven gear 51 → first dog tooth engagement mechanism 50 → first output shaft 48 → front axle drive gear 52. The second path is for power transmission from the power battery: power battery 70 → vehicle high-voltage wiring harness 33 → dual motor controller 30 → second motor high-voltage connector 32 → second motor 60. The second motor 60 converts electrical energy into mechanical energy for further transmission: second motor 60 → second motor input shaft 61 → second motor input gear 62 → second motor output gear 63 → second motor intermediate shaft 65 → second motor second-gear drive gear 66 → second motor second-gear driven gear 67 → second dog-tooth engagement mechanism 68 → first output shaft 48 → front axle drive gear 52. The power after convergence passes through the front axle drive gear 52 → front axle driven gear 53 → torque limiter 59 → second output shaft 54 ​​→ front axle quasi-hyperboloid drive gear 55 → front axle quasi-hyperboloid driven gear 57 → front axle differential assembly 56 → half shaft 110 → two front wheels 120. In this mode, the engine 10 and the second motor 60 work together to drive, resulting in greater output torque, suitable for high-power demand scenarios such as climbing and overtaking.

[0074] like Figure 14 As shown, in the longitudinally mounted four-wheel drive hybrid system of this application, when the engine is in second-gear drive and the second motor is in parallel drive, its power transmission path is the same as... Figure 13 The difference between the engine's first gear and the second motor's parallel drive is that the first dog-tooth engagement mechanism 50 engages with the transmission's second gear driven gear 49, which is suitable for high-power demand scenarios at medium and high speeds, such as high-speed overtaking, and can quickly improve the vehicle's power performance.

[0075] like Figure 15As shown, in the four-wheel drive mode of the longitudinally mounted four-wheel drive hybrid system of this application, the second motor outputs a large torque with a high speed ratio. Its power transmission path is: power battery 70 → vehicle high-voltage wiring harness 33 → dual-motor controller 30 → second motor high-voltage connector 32 → second motor 60. The second motor 60 converts electrical energy into mechanical energy for further transmission: second motor 60 → second motor input shaft 61 → second motor input gear 62 → second motor output gear 63 → second motor intermediate shaft 65 → second motor first gear drive gear 64 → second motor first gear driven gear 69 → second dog-tooth engagement mechanism 68 → first output shaft 48. At this time, the power is divided into two power transmission paths. Specifically, the first path is the front axle drive path: first output shaft... 48 → Front axle drive gear 52 → Front axle driven gear 53 → Torque limiter 59 → Second output shaft 54 ​​→ Front axle hypoid drive gear 55 → Front axle hypoid driven gear 57 → Front axle differential assembly 56 → Half shaft 110 → Left and right front wheels 120; The second path is the rear axle drive path: First output shaft 48 → Rear axle drive gear 81 → Rear axle driven gear 82 → Third output shaft 83 → Drive shaft 58 → Clutch 71 → Fourth output shaft 72 → Rear axle differential assembly 73 → Half shaft 110 → Left and right rear wheels 120; In this mode, the second motor 60 uses a first gear ratio to output high torque, and the front and rear axles drive together, which is suitable for off-road and low-traction road surface scenarios, and can realize cross-axle power dispatching to improve the ability to get out of trouble.

[0076] The operating states of the engine 10, the first motor 40, the second motor 60, the first dog-tooth engagement mechanism 50, and the second dog-tooth engagement mechanism 68 under various operating conditions are shown in Table 1 below:

[0077] Table 1 shows the operating status of the longitudinal four-wheel drive hybrid system under different working conditions.

[0078]

[0079] Another aspect of the present invention is to provide a control method for a longitudinally mounted four-wheel drive hybrid system, for controlling the aforementioned longitudinally mounted four-wheel drive hybrid system, comprising the following steps:

[0080] Step S1: Obtain vehicle status parameters, including one or more of the following: vehicle speed, engine torque, battery charge, vehicle required torque, motor drive efficiency, and engine drive efficiency.

[0081] Specifically, the vehicle control unit (VCU) integrates data from various sensors and systems to collect vehicle status parameters in real time. These status parameters include one or more of the following: vehicle speed, engine torque, battery charge (SOC), vehicle required torque, motor drive efficiency, and engine drive efficiency. Vehicle speed is collected by a vehicle speed sensor, engine torque is collected by a torque sensor, battery charge is provided by the BMS system, vehicle required torque is calculated based on accelerator pedal travel and brake pedal travel, and motor and engine drive efficiencies are queried in real time using a preset efficiency graph.

[0082] Step S2: Based on the state parameters, control the engagement state of the first dog tooth engagement mechanism, the second dog tooth engagement mechanism, and the clutch, so that the longitudinal four-wheel drive hybrid system switches between pure electric drive mode, engine direct drive mode, and series drive mode.

[0083] Specifically, based on the collected state parameters, the optimal working mode is determined through a preset efficiency optimization algorithm, and control signals are sent to the first dog tooth engagement mechanism 50, the second dog tooth engagement mechanism 68 and the clutch 71 to control their engagement or disengagement state, so that the longitudinal four-wheel drive hybrid system can seamlessly switch between pure electric drive mode, engine direct drive mode and series drive mode, ensuring that the system always operates in the high-efficiency range.

[0084] In this embodiment, the specific execution logic of the longitudinal four-wheel drive hybrid system of this application is as follows: when the battery charge is ≥30%, the vehicle speed is ≤60km / h, and the vehicle's required torque is ≤150N. When the vehicle speed is m, it prioritizes switching to pure electric drive mode to achieve zero emissions and low noise driving. When the battery charge is <20% and the vehicle speed is ≤40km / h, it switches to series drive mode, where the engine operates in its high-efficiency range to drive the first motor to generate electricity, which then powers the second motor to drive the vehicle, avoiding inefficient engine operation. When the vehicle speed is ≥40km / h and the engine's drive efficiency is higher than the motor's drive efficiency, it switches to engine direct drive mode. At low speeds (40-60km / h), the first dog-tooth engagement mechanism engages with the first gear of the transmission, and at high speeds (≥60km / h), the second gear engages, ensuring the engine operates in its high-efficiency range. When the vehicle's required torque is >300N... When the vehicle is in a state of m (such as climbing hills or overtaking) or when the single-axle adhesion is less than 30% (such as off-road or low-traction surfaces), the clutch is engaged to switch to four-wheel drive mode. The first output shaft simultaneously distributes power to the front drive axle and the rear drive axle, improving power output and off-road capability.

[0085] The present invention also provides a vehicle comprising the above-described longitudinally mounted four-wheel drive hybrid system.

[0086] The operating modes of the vehicle under different vehicle conditions are shown in Table 2 below, which can adapt to various driving scenarios.

[0087] Table 2 Operating Modes under Different Vehicle Conditions

[0088]

[0089] Specifically, when the vehicle is operating at low speed and in congested conditions: when the power battery 70 has a normal charge level (SOC≥30%), the system drives the vehicle in pure electric mode to achieve zero-emission and low-noise driving; when the power battery 70 has a low charge level (SOC<20%), the system switches from pure electric drive mode to series drive mode by starting the engine 10 while driving. The engine 10 operates in the high-efficiency range to generate electricity, ensuring continuous vehicle operation.

[0090] When the vehicle is operating at medium speeds: When the battery charge is in the high range (SOC≥50%), to ensure the system's regenerative braking effect and achieve a longer driving range, the system drives in pure electric mode and actively manages the battery charge. When the battery charge is in the normal range (30%≤SOC<50%), the system selects a suitable hybrid mode according to an optimization strategy. For example, when the wheel-side drive torque demand is low, the engine is selected in first gear direct drive to reduce energy conversion loss, while the excess torque of the engine drives the first motor to generate electricity, avoiding inefficient operation of the engine. When the torque demand is high, the system switches to a parallel drive mode of the engine and the second motor to improve power output.

[0091] When the vehicle is operating at high speed: the system switches to the engine's second gear direct drive mode, allowing the engine to run in the efficient speed range (1500-2500rpm) to improve fuel economy; when a large power demand is required, such as for overtaking, it automatically switches to the engine's second gear and the second motor's parallel drive mode to quickly increase power.

[0092] When the vehicle is in the energy recovery phase, the second motor 60 maintains a fixed speed ratio with the wheel 120, and can realize braking energy recovery under various vehicle speed deceleration conditions. Moreover, there is no gear shifting action during the braking energy recovery process, and the recovery efficiency is stable.

[0093] Example 2

[0094] Please refer to Figure 2The figure shows a longitudinal four-wheel drive hybrid system in the second embodiment of the present invention. The difference between the longitudinal four-wheel drive hybrid system in this embodiment and the longitudinal four-wheel drive hybrid system in the first embodiment is that the separate rear axle drive gear pair (i.e., the rear axle drive gear 81 and the rear axle driven gear 82) is removed, and the torque limiter 59 provided on the second output shaft 54 ​​is removed, so that the rear drive axle and the front drive axle share the front axle drive gear pair (i.e., the front axle drive gear 52 and the front axle driven gear 53).

[0095] The advantages of this design are its more compact structure, reduced number of components, lower manufacturing costs and layout complexity, and shorter power transmission path to the rear axle. However, since the front axle drive gear 52 and the front axle driven gear 53 need to bear all the torque of the front and rear drive axles, their gear module and tooth width need to be increased accordingly to meet the torque carrying requirements. This embodiment is suitable for urban commuter passenger vehicles with high requirements for structural compactness and relatively low requirements for extreme overload protection.

[0096] Example 3

[0097] Please refer to Figure 3 The figure shows a longitudinal four-wheel drive hybrid system in the third embodiment of the present invention. The difference between the longitudinal four-wheel drive hybrid system in this embodiment and the longitudinal four-wheel drive hybrid system in the first embodiment is that the separate front axle drive gear 52 and front axle driven gear 53 are eliminated. The front drive axle and the rear drive axle share the rear axle drive gear 81 and the rear axle driven gear 82. The torque limiter 59 is used to limit the torque transmitted to the front drive axle, thereby protecting the front drive axle and preventing the front drive axle from being subjected to excessive load and causing failure.

[0098] The advantages of this design are a more compact front drive axle structure, occupying less space, and precise protection of the front axle transmission components through the torque limiter 59, extending their service life. Meanwhile, the rear axle drive gear 81 and rear axle driven gear 82 have stronger torque-carrying capacity, making them suitable for high-power output scenarios. This embodiment is suitable for vehicle models with high requirements for front axle space layout and a need to balance power performance and system protection, such as light commercial vehicles and off-road passenger vehicles.

[0099] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," 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 the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0100] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this application should be determined by the appended claims.

Claims

1. A longitudinally mounted four-wheel drive hybrid system, characterized in that, It includes an engine, a shock absorber, a power battery, and a drive assembly. The engine is arranged longitudinally along the vehicle and is connected to the drive assembly through the shock absorber to transmit mechanical work and dampen vibrations. The drive assembly includes a dual-motor controller, a first motor drive assembly, a second motor drive assembly, a transmission assembly, a front drive axle, and a rear drive axle; The transmission assembly includes a power input shaft, a first output shaft, and a first dog gear engagement mechanism. The first dog gear engagement mechanism is used to selectively transmit the power of the engine to the first output shaft at different speed ratios. The first output shaft is used to simultaneously distribute power to the front drive axle and the rear drive axle. The output end of the first motor drive component is always connected to the power input shaft. The second motor drive assembly includes a second motor and a second dog-tooth engagement mechanism, the second dog-tooth engagement mechanism being used to selectively transmit the power of the second motor to the first output shaft at different speed ratios; The front drive axle includes a second output shaft, a torque limiter, and a front axle differential assembly. The torque limiter is disposed on the second output shaft and is used to limit the torque transmitted to the front drive axle. The rear drive axle is connected to the first output shaft via a drive shaft, and the rear drive axle includes a clutch and a rear axle differential assembly to achieve four-wheel drive; The transmission assembly is a two-speed transmission assembly. The power input shaft is provided with a first-speed drive gear and a second-speed drive gear. The first output shaft is provided with a first-speed driven gear and a second-speed driven gear that mesh with the first-speed drive gear and the second-speed drive gear, respectively. The first dog-tooth engagement mechanism is located on the first output shaft and is used to selectively engage the first gear driven gear or the second gear driven gear of the transmission. The second motor drive assembly also includes a second motor input shaft and a second motor intermediate shaft. The second motor input shaft is provided with a second motor input gear, and the second motor intermediate shaft is provided with a second motor output gear, a second motor first gear drive gear and a second motor second gear drive gear. The second motor output gear meshes with the second motor input gear. The first output shaft is provided with a second motor first gear driven gear and a second motor second gear driven gear that mesh with the second motor first gear drive gear and the second motor second gear drive gear, respectively; The second dog-tooth engagement mechanism is located on the first output shaft and is used to selectively engage the first gear driven gear or the second gear driven gear of the second motor.

2. The longitudinally mounted four-wheel drive hybrid system according to claim 1, characterized in that, The torque limiter is a face dog-tooth clutch structure. The torque limiter includes locking teeth and a spring. The locking teeth are connected to the second output shaft via a spline.

3. The longitudinally mounted four-wheel drive hybrid system according to claim 1, characterized in that, The first motor drive assembly includes a first motor, a first motor input shaft, a first motor input gear, a first motor idler gear, and a first motor output gear; The first motor output gear is coaxially fixed on the power input shaft and is constantly meshed with the first motor input gear through the first motor idler gear, so that the first motor and the engine are always connected, which is used to selectively start the engine or recover the excess torque of the engine to generate electricity.

4. The longitudinally mounted four-wheel drive hybrid system according to claim 3, characterized in that, The engine, the first motor, and the second motor are arranged in a parallel axis configuration.

5. The longitudinally mounted four-wheel drive hybrid system according to claim 1, characterized in that, The dual-motor controller is electrically connected to the power battery via the vehicle's high-voltage wiring harness.

6. A control method for a longitudinally mounted four-wheel drive hybrid system, used to control the longitudinally mounted four-wheel drive hybrid system according to any one of claims 1 to 5, characterized in that, Includes the following steps: Obtain vehicle status parameters, which include one or more of the following: vehicle speed, engine torque, battery charge, vehicle required torque, motor drive efficiency, and engine drive efficiency. Based on the state parameters, the engagement states of the first dog-tooth engagement mechanism, the second dog-tooth engagement mechanism, and the clutch are controlled, so that the longitudinal four-wheel drive hybrid system switches between pure electric drive mode, engine direct drive mode, and series drive mode.

7. A vehicle, characterized in that, The vehicle includes a longitudinally mounted four-wheel drive hybrid system as described in any one of claims 1 to 5.

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