Hybrid off-road vehicle structure

Abstract

The application relates to the technical field of automobile structures and discloses a hybrid off-road vehicle structure, wherein a front subframe and a rear subframe are connected to a front and rear of a vehicle beam large frame respectively, a three-door structure is formed by arranging a front bulkhead and a rear bulkhead above the vehicle beam large frame, and a front engine compartment, a passenger compartment and a rear engine compartment are formed respectively; a front motor and a front power battery are arranged in the front engine compartment, and an engine transmission assembly is arranged in the rear engine compartment, so that the weight of the front part of the vehicle body is reduced, the front hood is lowered, and the field of view is improved; the front motor is connected with a front reduction and differential integrated assembly, and the engine transmission assembly is connected with a rear axle differential; a side-hinged back door is arranged at the rear side of the rear engine compartment, and a tool placing platform is arranged at the inner side of the back door; the application has the advantages of simple structure, rapid power response, good field of view of the driving position and convenient field maintenance of the engine transmission assembly.

Description

Technical Field

[0001] This invention relates to the field of automotive structural technology, and in particular to a hybrid off-road vehicle structure. Background Technology

[0002] Current off-road vehicles generally adopt a boxy design with the engine located in the engine compartment and a high front end, resulting in poor visibility. This is especially problematic when climbing hills, where the road ahead is obscured, creating a significant psychological barrier for novice off-roaders. Furthermore, the front-mounted engine and transmission contribute to a heavier front end, making it difficult to extricate oneself from potholes. While some rear-mounted engine solutions exist, they only address the forward center of gravity issue and still require a transfer case and a long driveshaft running the length of the vehicle to transmit power, resulting in low transmission efficiency and slow power response. The transfer case also occupies considerable space under the vehicle, increasing overall weight and structural complexity. Moreover, the current rear-mounted engine design lacks sufficient consideration for ease of field maintenance; engine repairs still require specialized tools and facilities, making independent repairs difficult in complex off-road environments. Summary of the Invention

[0003] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a hybrid off-road vehicle structure to solve the above problems.

[0004] To achieve the above objectives, the present invention is implemented through the following technical solution: A hybrid off-road vehicle structure includes a frame beam, which is connected to a front subframe and a rear subframe. A three-box structure is formed above the frame beam by a front bulkhead and a rear partition, comprising a front engine compartment, a passenger compartment, and a rear engine compartment. The front engine compartment houses a front motor and a front power battery, while the rear engine compartment houses an engine and transmission assembly to reduce the weight of the front of the vehicle and lower the hood to improve visibility. The front motor is connected to a front reduction differential assembly, and the engine and transmission assembly is connected to a rear axle differential. The rear engine compartment is equipped with a side-opening tailgate, and a tool storage platform is located on the inside of the tailgate.

[0005] As a further implementation, the front engine compartment is located in front of the front bulkhead, increasing the capacity of the front power battery in the front engine compartment to achieve a 50:50 weight distribution between the front and rear axle loads.

[0006] As a further implementation, the rear engine compartment is located behind the rear bulkhead, the rear engine compartment has no rear floor, the engine and transmission assembly is mounted on the rear subframe, and the rear subframe is mounted on the vehicle frame.

[0007] As a further implementation, the rear subframe is provided with longitudinally arranged slide rails, and the engine and transmission assembly is mounted on the slide rails. Opening the tailgate allows the engine and transmission assembly to be pulled backward for easy maintenance. The rear axle differential is mounted on the rear subframe. The output end of the engine and transmission assembly is connected to the input end of the rear axle differential via a drive shaft with a universal joint. A spline quick-release joint is provided in the middle of the drive shaft.

[0008] As a further implementation, the surface of the rear partition is provided with a sound insulation and noise reduction structure.

[0009] As a further implementation, the front motor and the front power battery are mounted on the front subframe; The output end of the front motor is connected to the input end of the front reduction differential assembly, which is mounted on the front subframe.

[0010] As a further implementation, the overall volume of the front motor and the front power battery is smaller than the overall volume of the engine and transmission assembly, so as to shorten the longitudinal length of the front engine compartment and move the driver's seat forward relatively.

[0011] As a further implementation, the engine and transmission assembly integrates an ISG motor, which is connected to a motor controller in the front engine compartment via a high-voltage wiring harness. The motor controller is connected to a high-voltage power distribution unit, which is connected to the front power battery.

[0012] As a further implementation, the inner side of the tailgate is provided with a fastener to fix the vehicle tools to the inner side of the tailgate, and the rear engine compartment is provided with an inspection light.

[0013] As a further implementation, the tool placement platform is arranged perpendicularly to the inside of the rear door.

[0014] The beneficial effects of the present invention are as follows: 1. This invention eliminates the need for an engine and transmission in the front engine compartment, significantly reducing its longitudinal length and front overhang to less than 0.8m, a reduction of 30% to 40% compared to traditional off-road vehicles. This also lowers the hood height, allowing the driver's seat to be moved forward by 5cm to 10cm, creating a combination of near-windshield and high seating position visibility. The driver's forward field of vision is expanded by 15% to 20% compared to traditional off-road vehicles, and the A-pillar lateral blind spot is reduced by 40%. This makes the judgment of obstacles ahead more accurate during off-road driving, effectively overcoming the problems of poor visibility and fear of climbing hills for novice drivers in traditional off-road vehicles.

[0015] 2. This invention adopts a dual-axle independent drive architecture with a rear-mounted engine driving the rear axle and a front-mounted motor driving the front axle. This eliminates the transfer case and long driveshaft running the length of the vehicle required in existing rear-mounted engine solutions, significantly shortening the transmission path, increasing transmission efficiency, reducing overall vehicle weight, and simplifying the structure. Engine power is directly transmitted from the transmission to the rear axle differential, resulting in more direct power response. The front motor's electrical response time is in the millisecond range, leading to extremely rapid front axle power response. The overall vehicle's performance in off-road acceleration, traction, and dynamic control is significantly superior to traditional rear-mounted engine off-road vehicles equipped with a transfer case.

[0016] 3. The rear hatch of this invention features a side-opening design, and the engine and transmission assembly slides with the rear subframe via a slide rail. A splined quick-release connector is located in the middle of the drive shaft. This allows for the complete removal of the engine and transmission assembly even in the absence of specialized tools and facilities in the field, providing ample space for maintenance and significantly lowering the technical barrier to independent field repair. By eliminating the trunk, the engine and transmission assembly is placed here, providing ample space. The side-opening rear hatch further enhances the maintenance space. Combined with the onboard tools, tool storage platform, and power supply interface design, this addresses the shortcomings in the convenience of field repair for existing rear-engine off-road vehicles, improving the convenience of field operations and independent repair capabilities.

[0017] 4. By flexibly adjusting the capacity of the front power battery, this invention can achieve a golden weight ratio of 50:50 between the front and rear axle loads, resulting in balanced front and rear axle loads, excellent handling performance, and reduced difficulty in getting out of mud due to excessive weight during off-road driving, thus significantly improving overall handling performance.

[0018] 5. The hybrid power system of this invention balances off-road performance with daily fuel economy, and can flexibly switch according to different road conditions. During off-road driving, it fully utilizes the combined power advantages of the engine and electric motor, while switching to pure electric mode during urban commuting reduces fuel consumption and emissions. A charging port is located on the exterior of the vehicle body outside the front engine compartment, allowing connection to a charging pile for external charging of the front power battery 12, further reducing daily operating costs. Torque vector control ensures that the power transfer response time when one wheel slips is within 0.5 seconds, and the traction response speed is approximately 3 times faster than that of a traditional mechanical differential lock, significantly improving traction capability under extreme off-road conditions. Attached Figure Description

[0019] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0020] Figure 1 This is a schematic diagram of the hybrid off-road vehicle structure layout in an embodiment of the present invention; Figure 2This is a schematic diagram of the rear structure of the hybrid off-road vehicle in an embodiment of the present invention.

[0021] The diagram exaggerates the spacing or dimensions between parts to show their positions; the diagram is for illustrative purposes only.

[0022] The components include: 1. Engine and transmission assembly; 2. Fuel tank; 3. Rear partition; 4. Main frame; 5. Rear subframe; 6. Front motor; 7. Cooling module; 8. Front bulkhead; 9. HVAC; 10. Front bumper beam; 12. Front power battery; 13. Rear suspension; 14. Exhaust muffler; 15. Vehicle tools; 16. Tool storage platform; 17. Rear tailgate. Detailed Implementation

[0023] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0024] Example 1 In a typical embodiment of the present invention, reference is made to Figures 1-2 As shown, a hybrid off-road vehicle structure includes a vehicle beam frame 4, which is the main load-bearing component of the non-load-bearing body. It is made of high-strength steel box-type longitudinal beams and runs through the entire vehicle longitudinally, providing basic torsional stiffness and collision safety for the whole vehicle.

[0025] The front end of the main frame 4 is connected to the front subframe, and the rear end of the main frame 4 is connected to the rear subframe 5. The front subframe and the rear subframe 5 serve as the installation base for various functional modules in the front engine compartment and the rear engine compartment, respectively.

[0026] Above the main frame 4, the vehicle body is longitudinally divided into three independent functional compartments by setting the front bulkhead 8 and the rear partition 3, forming the front engine compartment, passenger compartment and rear engine compartment from front to back, thus forming a three-box structure.

[0027] The front bulkhead 8 is located between the front engine compartment and the passenger compartment, structurally separating the electrical components of the front engine compartment from the passenger compartment; the rear bulkhead 3 is located between the passenger compartment and the rear engine compartment, structurally and thermally isolating the engine and transmission assembly 1 in the rear engine compartment from the passenger compartment. The surface of the rear bulkhead 3 is equipped with a sound insulation and noise reduction structure. For example, a composite layer of sound-absorbing cotton and sound-insulating felt can be pasted on the passenger compartment side of the rear bulkhead 3, with a thickness of 20mm to 40mm, to effectively attenuate the noise and vibration generated by the engine and transmission assembly 1 in the rear engine compartment during operation, ensuring the passenger compartment's riding comfort.

[0028] The front engine compartment is located on the front side of the front bulkhead 8, and it houses the front motor 6, the front power battery 12, the heat dissipation module 7, and the front anti-collision beam 10. Since the engine and transmission are not located in the front engine compartment, its longitudinal length can be significantly shortened compared to the front engine compartment of a traditional off-road vehicle, and the front overhang length can be reduced to less than 0.8m, a reduction of 30% to 40% compared to traditional off-road vehicles.

[0029] Because the overall volume of the front motor and front power battery is smaller than that of the engine and transmission assembly, and the engine and transmission assembly is placed at the rear, the space required in the front engine compartment can be reduced, thereby reducing the volume of the front engine compartment. This allows for a reduction in the longitudinal length of the front engine compartment, resulting in a significant reduction in the front overhang, improving the vehicle's longitudinal approach angle and enhancing its passability in extreme terrain. On the other hand, it also allows for a reduction in the height of the hood.

[0030] Reducing the volume of the front engine compartment shortens its longitudinal length, allowing the driver's seat to be moved forward by 5cm to 10cm while maintaining the high seating position characteristic of off-road vehicles (seat height not less than 80cm from the ground). This creates a "near the windshield + high seating position" vision combination, expanding the driver's forward field of vision by 15% to 20% compared to traditional off-road vehicles. The side blind spot of the A-pillar is reduced by 40%, making the judgment of obstacles ahead more accurate when driving off-road and effectively reducing the psychological fear of novice off-roaders caused by limited visibility when climbing hills.

[0031] The rear engine compartment is located behind the rear bulkhead 3. It houses the engine and transmission assembly 1, the fuel tank 2, and an exhaust muffler 14, as well as the rear suspension 13. The rear engine compartment features a floorless design, meaning there is no enclosed floor structure at the bottom. The engine and transmission assembly 1 is directly mounted on the rear subframe 5, which is fixedly connected to the rear end of the main frame 4, providing stable support for the engine and transmission assembly 1. This floorless design simplifies the rear compartment structure and provides a structural foundation for field maintenance.

[0032] Since the engine and transmission assembly 1 is located in the rear engine compartment, there is no need to set up a traditional luggage compartment behind the rear seats in the passenger compartment. The second-row space can be extended backward for luggage storage, further improving the practicality of the vehicle.

[0033] In terms of vehicle body structure, this invention adopts a non-load-bearing body and is equipped with a main frame 4 to ensure torsional rigidity and collision safety. The rear subframe 5 uses high-strength steel box-type longitudinal beams, combined with transverse reinforcing beams, to form a frame-type load-bearing structure with a torsional strength of not less than 35,000 N·m / °, which is about 50% higher than that of traditional off-road vehicle rear subframes. The longitudinal beams of the rear subframe 5 have pre-drilled standardized modification holes with a hole spacing of 50mm, which can be used to install off-road modification accessories such as auxiliary fuel tanks, dual spare tire carriers, and tow hooks, meeting the personalized modification needs of hardcore off-road enthusiasts.

[0034] The hybrid power system of the present invention adopts a dual-axis independent drive architecture of "rear-mounted engine driving the rear axle + front-mounted motor driving the front axle", which is fundamentally different from the existing technology where the rear-mounted engine solution requires a transfer case and a long drive shaft running through the whole vehicle. The present invention eliminates the transfer case, resulting in a shorter power transmission path, a simpler structure, and a lighter overall vehicle weight.

[0035] The specific structure of the rear-mounted power module is as follows: the engine and transmission assembly 1 is mounted on the rear subframe 5. The engine and transmission assembly 1 includes an engine, a transmission, and an ISG motor integrated thereon.

[0036] The engine can be a 2.0T to 3.0T turbocharged engine with a maximum power of 250kW to 350kW; the transmission can be an 8AT off-road dedicated automatic transmission, which can provide stable power output under complex off-road conditions. The output end of the engine and transmission assembly 1 is connected to the rear axle differential via a drive shaft. The rear axle differential is mounted on the rear subframe 5. The two output ends of the rear axle differential are connected to the left and right rear wheels respectively via constant velocity universal joint half-shafts, realizing engine drive to the rear axle. The rear suspension 13 is connected between the rear subframe 5 and the rear wheels, allowing the rear wheels to move independently and ensuring the rear axle's ground contact on off-road surfaces.

[0037] The engine and transmission assembly 1 integrates an ISG motor, which is coaxially connected to the engine crankshaft and has the dual functions of starting the engine and generating electricity while driving. The ISG motor is connected to the motor controller in the front engine compartment via a high-voltage wiring harness. The motor controller is connected to the high-voltage power distribution unit, which is connected to the front power battery 12, forming a complete high-voltage electrical circuit to enable the engine to charge the front power battery.

[0038] The high-voltage wiring harness is arranged longitudinally along the bottom of the vehicle body, passing through a wiring harness protection channel beneath the passenger compartment floor. This channel utilizes a metal conduit structure, providing waterproofing, impact resistance, and heat insulation to ensure the high-voltage wiring harness is not damaged by chassis impacts during off-road driving. During operation, the ISG motor switches to generator mode under engine drive, converting mechanical energy into electrical energy. After rectification by the motor controller, the electrical energy is used to charge the forward power battery 12 via the high-voltage power distribution unit, thus providing supplemental power during driving.

[0039] The front engine compartment houses the front motor 6 and the front power battery 12, both mounted on the front subframe. The front power battery 12 can be a lithium iron phosphate battery with a capacity of 10kWh to 20kWh, a weight not exceeding 150kg, and an IP68 or higher waterproof protection rating. It is also equipped with a quick-release aluminum alloy protective plate on the outside, balancing protection and ease of maintenance.

[0040] The front power battery 12 also features a low-temperature preheating function, allowing it to start normally in temperatures as low as -30°C, making it suitable for off-road use in cold regions. The front motor 6 has a maximum power of 120kW to 180kW and a peak torque of 300N·m. The output of the front motor 6 is connected to the input of the front reduction differential assembly, which is fixedly mounted on the front subframe. Its two outputs are connected to the left and right front wheels respectively via constant velocity universal joint half-shafts, enabling the front motor 6 to independently drive the front axle. The overall volume of the front motor 6 and the front power battery 12 is smaller than that of the engine and transmission assembly 1, which is a structural prerequisite for shortening the longitudinal length of the front engine compartment.

[0041] This embodiment utilizes an off-road-specific electronic control system to coordinate the power distribution between the engine (rear drive) and the electric motor (front drive), supporting multiple driving modes. In climbing mode, the torque distribution between the front and rear axles is locked at 50:50 to ensure balanced traction for all four wheels. In sand dune bashing mode, the torque distribution is 30:70, with the rear axle providing stronger thrust. In snow mode, the torque distribution is 60:40, with the front axle providing stronger traction to prevent skidding. In pure electric mode, only the front motor (6) drives the front axle, and the engine is off, suitable for low-speed urban driving to reduce fuel consumption and emissions. In hybrid mode, the electronic control system intelligently adjusts the torque distribution ratio between the front and rear axles based on parameters such as vehicle speed, gradient, and battery state of charge, balancing power and economy. Combined with torque vectoring control, when one wheel slips, the electronic control system can complete power transfer within 0.5 seconds, with a traction response speed approximately three times faster than traditional mechanical differential locks, significantly improving the ability to escape from extreme off-road conditions.

[0042] Because this invention eliminates the transfer case, the engine's power is directly transmitted from the transmission to the rear axle differential via a short driveshaft, eliminating the need for long longitudinal transmission. This significantly shortens the transmission path, resulting in higher transmission efficiency and more direct power response. The front motor 6 directly drives the front axle, with a response time in the millisecond range, ensuring extremely rapid power response from the front axle. This combination significantly improves the vehicle's off-road acceleration, obstacle removal, and dynamic control performance compared to traditional rear-engine off-road vehicles equipped with a transfer case.

[0043] In terms of weight distribution, the present invention arranges the engine and transmission assembly 1 in the rear engine compartment and the front motor 6 and the front power battery 12 in the front engine compartment. By adjusting the capacity of the front power battery 12 (which can be flexibly selected within the range of 10kWh to 20kWh), the front and rear axle load ratio can be flexibly balanced to achieve a golden weight ratio of 50:50.

[0044] The balanced distribution of front and rear axle loads significantly improves the vehicle's handling performance. During off-road driving, the steering response is more linear, and the front axle is less likely to get stuck in mud due to excessive weight, significantly reducing the difficulty of getting out of the mud. Meanwhile, the front power battery pack 12 is located in the front engine compartment rather than under the chassis, effectively avoiding the risk of chassis impact damage to the battery pack during off-road driving and improving battery safety.

[0045] Regarding the intake and exhaust systems, the engine's intake system is located in the rear engine compartment, with an auxiliary air intake at the C-pillar. The intake position can be flexibly arranged according to the vehicle's shape. The stock vehicle has a high wading depth, and a snorkel can be added to the engine, allowing for an intake height of up to 1.2 meters, ensuring the engine remains water-free during deep wading conditions. The exhaust muffler 14 is located in the rear engine compartment, with a short exhaust pipe and low exhaust back pressure, which improves the engine's charging efficiency. The cooling module 7 is located at the front of the engine compartment, adjacent to the front bumper beam 10. The cooling system has been reinforced to support continuous operation in temperatures up to 45°C, meeting the needs of extreme off-road environments such as high-temperature deserts. It is understandable that it could also be located in the rear engine compartment. Alternatively, the cooling module 7 could be integrated into the front engine compartment.

[0046] A charging port is located on the side of the vehicle outside the front engine compartment. This port connects to an onboard charger and a high-voltage power distribution unit, which in turn connects to the front power battery 12. This allows for external charging via a charging station. Once charged, the front power battery 12 provides enough power to drive the front motor 6 in pure electric mode, suitable for urban commuting and reducing daily fuel consumption. The charging port has a protection rating of at least IP54, allowing for normal use in rainy or other inclement weather.

[0047] like Figure 1 and Figure 2 As shown, in response to the difficulty of self-repairing off-road vehicles in complex outdoor environments, a longitudinally arranged slide rail is provided on the rear subframe. The engine and transmission assembly is mounted on the slide rail. Opening the tailgate allows the engine and transmission assembly to be pulled backward, enabling quick extraction and maintenance of the engine and transmission assembly 1 in the absence of professional tools and facilities in the field.

[0048] A pair of parallel metal rails are provided in the longitudinal direction of the rear subframe 5. The metal rails extend longitudinally along the rear subframe 5 and open rearward, with the opening end corresponding to the opening position of the tailgate 17. The engine and transmission assembly 1 is connected to a slider via a mounting structure. The slider cooperates with the metal rails, and the slider can be fixed in relative position to the rails with bolts to prevent the engine and transmission assembly 1 from moving along the rails during driving. When maintenance is required, after loosening the quick-release bolts, the engine and transmission assembly 1 can slide rearward along the metal rails and be pulled out from the opening of the tailgate 17 without disassembling the vehicle interior. The operation is simple, and the purpose of the mounting structure is to reduce vibration.

[0049] The output end of the engine-transmission assembly 1 is connected to the input end of the rear axle differential via a drive shaft. A splined quick-release connector is provided in the middle of the drive shaft. The splined quick-release connector consists of an outer splined shaft and an inner splined sleeve. The outer splined shaft is fixed to the output end of the engine-transmission assembly 1, and the inner splined sleeve is fixed to the input drive shaft of the rear axle differential. After the outer splined shaft is inserted into the inner splined sleeve, it is fixed by a snap ring or locking pin, realizing the quick connection and disconnection of the drive shaft.

[0050] When the engine and transmission assembly 1 needs to be pulled out along the slide rail, first remove the snap ring or locking pin, the outer splined shaft exits from the inner splined sleeve, the drive shaft is disconnected at the splined quick-release joint, and the mechanical connection between the engine and transmission assembly 1 and the rear axle differential is released.

[0051] Because the drive shaft has a spline quick-release connector in the middle, the drive shaft itself does not need to be removed. Only the spline connector needs to be disconnected to extract the engine and transmission assembly 1, which greatly shortens the operation time.

[0052] The engine and transmission assembly 1 is connected to the vehicle body via oil and electrical lines, all using standardized quick-connect fittings. The oil quick-connect fitting connects the fuel tank 2 to the engine's fuel lines and engine coolant lines; it can be easily plugged in and out. The fitting has a built-in self-sealing valve that automatically seals when disconnected to prevent oil leakage. The fuel tank 2 is located below the passenger compartment, which is existing technology. An HVAC system 9 is also located at the front of the passenger compartment, which is existing technology.

[0053] The quick-connect connectors are used to connect the high-voltage wiring harness of the ISG motor and the low-voltage wiring harness of the engine sensors and actuators. They are waterproof multi-core quick-connect connectors, operable with one hand, and the insertion and extraction force does not exceed 50N, facilitating operation with gloves in the field. All of the above quick-connect connectors are located on the same side of the engine and transmission assembly 1, allowing the operator to disconnect all connectors from the same position after opening the tailgate 17, without having to walk around the vehicle.

[0054] The rear axle differential is fixedly mounted on the rear subframe 5, and the rear suspension 13 is connected between the rear subframe 5 and the rear wheels. The rear axle differential does not move when the engine and transmission assembly 1 is removed and remains fixed in its original position. After the engine and transmission assembly 1 is removed, the input drive shaft of the rear axle differential is suspended, and the inner spline sleeve is exposed, allowing direct inspection of the spline wear.

[0055] Regarding the engine's intake and exhaust systems, a snorkel is installed on the engine. The intake pipe is connected to an auxiliary air intake at the C-pillar via a flexible hose. The hose is flexible enough that it will not detach due to stretching when the engine and transmission assembly 1 moves a certain distance along the slide rail (e.g., 100mm to 200mm to the initial inspection position), facilitating engine start-up tests at the initial inspection position. The exhaust pipe has a quick-release clamp connection point near the tailgate 17, allowing for quick disconnection of the exhaust pipe during maintenance, enabling the engine and transmission assembly 1 to be completely removed.

[0056] The quick-release maintenance system of this embodiment has significant advantages over the maintenance methods of rear-engine off-road vehicles in the prior art. In the prior art, rear-engine off-road vehicles usually require opening the engine hood from above for maintenance, which is difficult due to limited space around the engine and the difficulty in operating tools.

[0057] In this embodiment, the rear door 17 is a side-opening type, such as... Figure 2 As shown, the engine and transmission assembly 1 can be accessed from the rear by opening the tailgate 17. The tailgate 17 has an opening width of 1.2m to 1.5m, covering the entire width of the rear subframe 5, providing ample operating space. More importantly, the engine and transmission assembly 1 of this invention can be pulled out entirely to the rear, allowing operators to inspect and maintain various parts of the engine and transmission assembly 1 from outside the vehicle while standing, without having to bend over and lean into the narrow engine compartment, significantly reducing the technical threshold for independent field maintenance.

[0058] refer to Figure 2 As shown, the tailgate 17 can be a 180° swing-out type with an opening width of 1.2m to 1.5m, covering the full width of the rear engine compartment. When opened, it can fully expose the rear engine compartment and the rear end of the engine and transmission assembly 1, forming a spacious maintenance passage.

[0059] The inner side of the tailgate 17 is equipped with a fastener, which can be in the form of a hook, buckle or magnetic base. The vehicle tools 15 can be fixed to the inner side of the tailgate 17 by the fastener. Eight to ten commonly used maintenance tools, such as torque wrenches, socket sets, screwdriver sets, pliers, etc., can be fixed. The tools are hung neatly and orderly, and are easy to access, avoiding the tools from being scattered in the rear compartment and causing safety hazards.

[0060] A tool placement platform 16 is provided on the inside of the tailgate 17. The tool placement platform 16 is arranged perpendicular to the inside of the tailgate 17, meaning that when the tailgate 17 is opened to a 180° horizontal position, the tool placement platform 16 is in a horizontal plane and can be used as a temporary workbench. The tool placement platform 16 is supported by support legs, which can bear a weight of not less than 50kg, meeting the needs of placing toolboxes, parts, and tools on the tool placement platform 16. The surface of the tool placement platform 16 may have anti-slip textures to prevent tools from slipping off in off-road environments; the upper surface of the tool placement platform 16 may be recessed to prevent tools from falling off during driving; additional fixing structures can be added to the tool placement platform to further secure the tools.

[0061] In a preferred example, a maintenance light is provided in the rear engine compartment. The trunk light was originally located in the trunk, but when the engine and transmission assembly 1 is located in the rear engine compartment, it becomes a maintenance light.

[0062] In addition, an LED light holder can be installed at the top of the rear engine compartment to secure the LED light, with a built-in battery providing a range of no less than 8 hours. The LED light can also be equipped with a magnetic structure, allowing it to be attached to the metal structure of the engine and transmission assembly 1 or the rear subframe 5, providing illumination for maintenance at night or in low-light conditions.

[0063] The power supply for the inspection light can also be supplied through the 12V power interface located on the rear tailgate 17 or the inner side of the rear engine compartment. The output current of the 12V power interface is not less than 10A, which can power electric wrenches, air pumps and other power tools. The 12V power interface is connected to the vehicle's low-voltage battery through the body wiring harness and can still be used when the engine is off.

[0064] In one embodiment, a 220V power interface can also be provided on the tailgate 17. The 220V power interface is connected to the high-voltage system of the front power battery 12 through the vehicle inverter, which can provide power to power tools that require 220V AC power, further enhancing the ability to perform autonomous repairs in the field.

[0065] The tailgate 17 adopts a side-opening design rather than a top-opening design. In off-road environments with limited clearance, such as forest roads with many trees or low caves, the side-opening tailgate 17 is not restricted by overhead obstacles and can be opened normally. The opening formed by the side-opening tailgate 17 after opening is a vertical rectangle, which is consistent with the direction of the engine and transmission assembly 1 (horizontally backward). The operator can directly face the engine and transmission assembly 1 to operate without bending over or squatting. The tool placement platform 16 inside the tailgate 17 is directly in front of the operator when the tailgate 17 is fully opened, making it convenient to access tools.

[0066] like Figure 1As shown, the functional modules in the front engine compartment are integrated and arranged as follows: the heat dissipation module 7 is located at the very front of the front engine compartment, adjacent to the front bumper beam 10. The front face of the heat dissipation module 7 faces the front air intake grille, ensuring that the driving air can be directly cooled through the heat dissipation module 7. The heat dissipation module 7 includes an engine cooling radiator, a front motor 6 cooling radiator, and an air conditioning condenser. Each radiator is connected to the corresponding cooled component through an independent coolant circuit, without interfering with each other. After the engine coolant pipe is led out from the heat dissipation module 7, it runs longitudinally along the bottom of the vehicle, passing under the passenger compartment floor, and connects to the engine and transmission assembly 1 in the rear engine compartment. The coolant pipe is equipped with a metal protective sleeve to prevent damage from impacts during off-road driving. The HVAC 9 is located on the rear side of the front bulkhead 8, which is existing technology.

[0067] The front power battery 12 is positioned above the front subframe, between the front motor 6 and the front bulkhead 8. The front power battery 12 is protected by the front subframe, preventing direct exposure to the chassis and effectively avoiding direct impact from rocks, mud, etc., during off-road driving. A quick-release aluminum alloy skid plate is installed on the outside of the front power battery 12, allowing for quick removal without specialized tools when battery maintenance is required.

[0068] The high-voltage power distribution unit is located in the front engine compartment and centrally manages the distribution of high-voltage power from the front power battery 12. The high-voltage power distribution unit is connected to the motor controller of the front motor 6, the ISG motor controller, the on-board charger, and the DC / DC converter. The on-board charger connects to a charging port located on the side of the vehicle outside the front engine compartment. This charging port can be connected to an external charging station for external charging of the front power battery 12. The charging port has a protection rating of at least IP54, and its cover uses a spring-loaded self-locking structure to automatically close when not charging, preventing rainwater and mud from entering. The DC / DC converter converts the high-voltage DC power to 12V low-voltage DC power to supply the vehicle's low-voltage electrical systems, including lights, instruments, the ECU, and the 12V power interface on the tailgate 17.

[0069] In terms of longitudinal passability, this configuration shortens the front overhang to less than 0.8m, significantly improving the front longitudinal approach angle compared to traditional off-road vehicles. The rear engine compartment features a floorless design, freeing the rear suspension 13 from floor constraints. The rear suspension 13 can utilize a multi-link independent suspension structure, minimizing the rear overhang length while ensuring rear wheel travel and enhancing the rear longitudinal approach angle. The ground clearance of the main frame 4 is no less than 220mm, ensuring passability on surfaces with obstacles such as rocks and tree roots.

[0070] Regarding wading capability, the engine's air intake system is connected to an auxiliary air intake at the C-pillar via a flexible hose, allowing for an air intake height of up to 1.2 meters, significantly exceeding the wading depth of traditional off-road vehicles. The front power battery 12 has an IP68 or higher waterproof protection rating, while the front motor 6 and its controller also have a waterproof protection rating of at least IP67, ensuring the safety of the high-voltage electrical system during deep water wading. The rear engine compartment has no rear floor, and the bottom of the rear compartment is open, allowing water to flow freely out during wading without accumulating.

[0071] In terms of roll stability, due to the balanced 50:50 front and rear axle load distribution, the vehicle's roll center is more balanced, resulting in better roll stability than traditional off-road vehicles with a heavy front axle when driving on cross slopes. The front motor 6 and front power battery 12 are mounted on the front subframe, resulting in a relatively low center of gravity. The engine and transmission assembly 1 is mounted on the rear subframe 5, also located at a low position on the vehicle body. The overall center of gravity of the vehicle is lower than that of traditional off-road vehicles with the engine positioned higher, which helps improve roll stability.

[0072] In terms of braking performance, the balanced 50:50 front-to-rear axle load distribution makes the front-to-rear braking force distribution more reasonable. During braking, the front axle will not lock up prematurely due to excessive weight, and the rear axle will not lose braking force due to insufficient weight. The braking distance and braking stability are superior to those of traditional off-road vehicles with excessive front axle weight. At the same time, the braking energy recovery function is realized by the front motor 6. During braking, the front motor 6 switches to power generation mode, converting braking kinetic energy into electrical energy and feeding it back to the front power battery 12. While improving energy utilization efficiency, it also provides additional braking torque to the front axle.

[0073] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A hybrid off-road vehicle structure, characterized in that, The vehicle includes a frame beam, which connects to the front and rear subframes respectively. A three-box structure is formed on top of the frame beam by a front bulkhead and a rear partition, which respectively form a front engine compartment, a passenger compartment, and a rear engine compartment. The front engine compartment houses the front motor and the front power battery, while the rear engine compartment houses the engine and transmission assembly, in order to reduce the weight of the front of the vehicle and lower the hood to improve visibility. The front motor is connected to the front reduction differential assembly, and the engine and transmission assembly is connected to the rear axle differential; the rear engine compartment is equipped with a side-opening tailgate, and a tool storage platform is provided on the inside of the tailgate.

2. The hybrid off-road vehicle structure according to claim 1, characterized in that, The front engine compartment is located in front of the front bulkhead, increasing the capacity of the front power battery in the front engine compartment and achieving a 50:50 weight distribution between the front and rear axle loads.

3. The hybrid off-road vehicle structure according to claim 1, characterized in that, The rear engine compartment is located behind the rear bulkhead. The rear engine compartment has no rear floor. The engine and transmission assembly is mounted on the rear subframe, which is mounted on the vehicle frame.

4. The hybrid off-road vehicle structure according to claim 1, characterized in that, The rear subframe is equipped with longitudinally arranged slide rails, and the engine and transmission assembly is mounted on the slide rails. Opening the tailgate allows the engine and transmission assembly to be pulled backward for easy maintenance. The rear axle differential is mounted on the rear subframe. The output end of the engine and transmission assembly is connected to the input end of the rear axle differential via a drive shaft with a universal joint. A spline quick-release joint is provided in the middle of the drive shaft.

5. The hybrid off-road vehicle structure according to claim 1, characterized in that, The rear partition surface is provided with a sound insulation and noise reduction structure.

6. The hybrid off-road vehicle structure according to claim 1, characterized in that, The front motor and front power battery are mounted on the front subframe; The output end of the front motor is connected to the input end of the front reduction differential assembly, which is mounted on the front subframe.

7. The hybrid off-road vehicle structure according to claim 6, characterized in that, The overall volume of the front motor and front power battery is smaller than that of the engine and transmission assembly, so as to shorten the longitudinal length of the front engine compartment and move the driver's seat forward.

8. The hybrid off-road vehicle structure according to claim 1, characterized in that, The engine and transmission assembly integrates an ISG motor, which is connected to a motor controller in the front engine compartment via a high-voltage wiring harness. The motor controller is connected to a high-voltage power distribution unit, which is connected to the front power battery.

9. The hybrid off-road vehicle structure according to claim 1, characterized in that, The inner side of the tailgate is equipped with a fastener to secure the vehicle tools to the inside of the tailgate. The rear engine compartment is equipped with an inspection light.

10. The hybrid off-road vehicle structure according to claim 1, characterized in that, The tool placement platform is arranged perpendicularly to the inside of the rear door.

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