Low-oil-consumption four-wheel drive power system, control method and vehicle

Abstract

The invention discloses a low-oil-consumption four-wheel-drive-force system, a control method and a vehicle, and relates to the technical field of four-wheel-drive automobiles, the low-oil-consumption four-wheel-drive-force system comprises four wheels, the wheels are installed at one ends of drive shafts, a transfer case is connected between the drive shafts of two wheels, a rear main reducer assembly is connected between the drive shafts of the other two wheels, and the rear main reducer assembly is connected with the transfer case. The transfer case is connected with the rear main reducer assembly through a transmission shaft; one driving shaft is connected with an engine through a transmission; one side of the transfer case is connected with the separating mechanism; two sides of the rear main reducer assembly are connected with the separating mechanism; when the rotating speed difference is smaller than a set value, the separation mechanism is in a separation state to form a two-drive mode; when the rotating speed difference is larger than a set value, the separation mechanism is in a combined state to form a four-wheel-drive mode. When the vehicle keeps the two-wheel drive mode, the transfer case, the transmission shaft and the rear main reducer assembly do not rotate, redundant oil consumption waste caused by dragging resistance is reduced, meanwhile, the vehicle can be controlled to be converted from the two-wheel drive mode to the four-wheel drive mode, and the requirement for the four-wheel drive capacity is met.

Description

Technical Field

[0001] The present invention relates to the technical field of four-wheel drive vehicles, and in particular to a low-fuel-consumption four-wheel drive power system, a control method and a vehicle. Background Art

[0002] The statements herein merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] A vehicle's four-wheel drive technology can be divided into two categories according to the application scenario: full-time four-wheel drive and part-time four-wheel drive. Full-time four-wheel drive means that the four wheels always maintain power input during the vehicle's driving process, and the front and rear axle torque is dynamically distributed through the central differential; part-time four-wheel drive means that the vehicle drives in four-wheel drive mode when the vehicle slips, accelerates suddenly, or the vehicle's posture changes, and drives in two-wheel drive mode under other working conditions.

[0004] In existing part-time four-wheel drive systems, power transmission is mostly on-demand, meaning that power is generally only transmitted when the main drive wheels slip or when the vehicle requires four-wheel drive for a short period of time. Furthermore, most current part-time four-wheel drive power transmission systems involve the engine transmitting power to the transmission, which then transmits the power to the transfer case, then to the intermediate drive shaft, and finally to the rear main reducer assembly, before outputting the power to the rear wheels. In two-wheel drive mode, the transfer case, intermediate drive shaft, and rear main reducer assembly are constantly idling, which results in drag and idling losses, increasing the vehicle's fuel consumption and failing to meet customer demand for fuel-efficient four-wheel drive vehicles. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a low-fuel-consumption four-wheel drive power system, control method and vehicle. When the vehicle maintains a two-wheel drive mode, the transfer case, drive shaft and rear main reduction assembly will not rotate, thereby reducing the excess fuel waste caused by drag resistance. At the same time, the vehicle can be controlled to switch from two-wheel drive to four-wheel drive, meeting the demand for four-wheel drive capabilities.

[0006] In order to achieve the above object, the present invention is implemented through the following technical solutions: In a first aspect, an embodiment of the present invention provides a low-fuel-consumption four-wheel drive system, comprising four wheels, each of which is mounted on one end of a drive shaft, wherein a transfer case is connected between the drive shafts of two wheels, and a rear main reducer assembly is connected between the drive shafts of the other two wheels, wherein the transfer case and the rear main reducer assembly are connected via a transmission shaft; and one of the drive shafts is connected to an engine via a transmission; One side of the transfer case is connected to a separation mechanism, and both sides of the rear main reduction assembly are connected to separation mechanisms; when the speed difference is less than a set value, the separation mechanism is in a separation state, forming a two-wheel drive mode; when the speed difference is greater than the set value, the separation mechanism is in a connection state, forming a four-wheel drive mode.

[0007] As a further implementation, the separation mechanism includes a wedge-shaped movable gear and a wedge-shaped fixed gear, a thrust bearing is provided between the wedge-shaped movable gear and the wedge-shaped fixed gear, and the outer side of the wedge-shaped movable gear is in clearance fit with the separation fork; The separation fork is connected to a pushing mechanism, and the pushing mechanism is used to drive the separation fork to move axially so as to separate or combine the wedge-shaped movable gear and the wedge-shaped fixed gear.

[0008] As a further implementation, one side of the wedge-shaped movable gear has a plurality of wedge-shaped teeth, and the wedge-shaped fixed gear has a wedge-shaped tooth groove adapted to the wedge-shaped teeth.

[0009] As a further implementation, the pushing mechanism includes an actuator motor and a worm, the actuator motor is connected to the worm, and the release fork is engaged with the worm.

[0010] As a further implementation method, the separation mechanism also includes a controller, which includes a motor control module, a torque calculation module, and a speed calculation module. The motor control module is used to control the rotation of the execution motor, the torque calculation module is used to calculate the output torque of the execution motor, and the speed calculation module is used to calculate the speed of the execution motor rotor.

[0011] In a second aspect, an embodiment of the present invention further provides a method for controlling a low fuel consumption four-wheel drive system, comprising: The engine power is transmitted to the transfer case through the transmission and drive shaft. When the speed difference is less than the set value, the release mechanism is in the disengaged state, and the transmission power is directly transmitted to the wheels by the drive shaft. The rear main reduction assembly and the drive shaft are also in the disengaged state, forming a two-wheel drive. When the speed difference exceeds the set value, the separation mechanisms engage, coupling the transfer case to the drive shaft. Power is input from the engine through the transmission and drive shaft into the transfer case, then transmitted to the rear main reduction assembly through the drive shaft, and finally transmitted to the wheels through the drive shaft, forming four-wheel drive.

[0012] As a further implementation method, when the speed difference between the front and rear drive shafts tends to be consistent and is less than the set value, the separation mechanism is converted to a separation state, and no power is transmitted between the transfer case and the drive shaft and the rear main reduction assembly, and the system switches to two-wheel drive.

[0013] As a further implementation method, the pushing mechanism drives the separation fork to move axially, causing the wedge-shaped movable gear to undergo axial displacement. The wedge-shaped movable gear cooperates with the wedge-shaped fixed gear through a thrust bearing to achieve switching between the engaged state and the separated state of the separation mechanism.

[0014] As a further implementation method, during the two-wheel drive process, the transfer case, drive shaft and rear main reduction assembly do not idle.

[0015] In a third aspect, an embodiment of the present invention further provides a vehicle equipped with the low fuel consumption four-wheel drive power system.

[0016] The beneficial effects of the present invention are as follows: (1) The transfer case of the present invention is connected to a separation mechanism on one side, and the separation mechanisms are connected on both sides of the rear main reducer assembly. The separation mechanism on one side of the transfer case can control whether the power is transmitted to the rear wheels, and the separation mechanisms on both sides of the rear main reducer assembly can further control the power distribution between the left and right rear wheels; when the speed difference is less than the set value, the separation mechanism is in a separation state, forming a two-wheel drive mode, and the transfer case, drive shaft, and rear main reducer assembly will not rotate, thereby reducing the unnecessary fuel consumption caused by drag resistance; when the speed difference is greater than the set value, the separation mechanism is in a connection state, realizing the switching between two-wheel drive and four-wheel drive, meeting the demand for four-wheel drive capability.

[0017] (2) The separation mechanism of the present invention includes a wedge-shaped movable gear and a wedge-shaped fixed gear. A thrust bearing is provided between the wedge-shaped movable gear and the wedge-shaped fixed gear. The wedge-shaped movable and static gears in the separation mechanism ensure the separation and combination of power. The outer side of the wedge-shaped movable gear is clearance-matched with the separation fork. Under the action of the pushing mechanism, the wedge-shaped movable gear can be combined with or separated from the wedge-shaped fixed gear to realize the switching of the power transmission path; the thrust bearing is provided between the movable and static gears to prevent the two gears from being hard-coupled during the matching process, thereby causing gear wear.

[0018] (3) The present invention pre-sets the switching conditions. When the speed difference is less than the set value, the separation mechanism is in a separation state, the transfer case and the transmission are not engaged, and the transmission power is directly transmitted from the front drive shaft to the front wheels. The rear main reduction assembly and the rear drive shaft are also in a separation state. At this time, the vehicle realizes two-wheel drive, and the transfer case, the drive shaft and the rear main reduction assembly do not idle. When the speed difference is greater than the set value, the separation mechanism installed on the front drive shaft is engaged, and the transfer case is engaged with the drive shaft. The separation mechanisms on both sides of the rear main reduction assembly are also engaged, and the rear main reduction assembly is engaged with the rear drive shaft. The engine is input to the transfer case through the transmission via the front drive shaft, and then transmitted to the rear main reduction assembly through the drive shaft. The rear main reduction assembly is transmitted to the rear wheels through the rear drive shaft to realize four-wheel drive. When the speed difference tends to be consistent and is less than the set value, the separation mechanism is separated to realize switching between two-wheel drive and four-wheel drive. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0020] Figure 1 is a schematic structural diagram of a four-drive power system according to one or more embodiments of the present invention; Figure 2It is a schematic structural diagram of a separation mechanism according to one or more embodiments of the present invention.

[0021] Among them, 1. Engine; 2. Transmission; 3. Separation mechanism; 4. Transfer case; 5. Wheels; 6. Front drive shaft; 7. Transmission shaft; 8. Rear main reduction assembly; 9. Rear drive shaft; 31. Controller; 32. Wiring harness; 33. Actuator motor; 34. Rotor shaft; 35. Worm; 36. Disengagement fork; 37. Wedge-shaped movable gear; 38. Thrust bearing; 39. Wedge-shaped fixed gear; 371. Wedge-shaped teeth; 372. Groove structure; 391. Wedge-shaped tooth groove; 392. Protrusion structure. DETAILED DESCRIPTION

[0022] It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0023] For the convenience of description, if the words "front", "rear", "left" and "right" appear in the present invention, they only indicate that the front, rear, left and right directions are consistent with the drawings themselves, and do not limit the structure. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, they cannot be understood as limiting the present invention.

[0024] Explanation of terms: The rear main reducer assembly is the rear wheel main reducer assembly, including the main reducer gear set, differential, etc.

[0025] Example 1: In the existing ordinary timely four-wheel drive power transmission, the engine 1 transmits power to the transmission 2, the transmission 2 transmits power to the transfer case 4, and then transmits it to the rear main reducer assembly 8 through the drive shaft 7, and finally outputs it to the wheels 5. The decoupling mechanism is installed in front of the drive shaft 7 and the rear main reducer assembly 8, and separates and combines power with the rear main reducer assembly 8 through the drive shaft 7. This arrangement cannot independently control the separation and combination of power for the rear axle wheels 5. At the same time, in the two-wheel drive state, the decoupling mechanism can only disconnect the power of the rear main reducer assembly 8, while the transfer case 4 and the drive shaft 7 are still rotating, resulting in unnecessary fuel consumption.

[0026] Based on this, this embodiment provides a low fuel consumption four-wheel drive power system, such as Figure 1As shown, the vehicle primarily comprises an engine 1, a transmission 2, a disconnect mechanism 3, a drive shaft, a transfer case 4, a propeller shaft 7, a rear main reducer assembly 8, and four wheels 5. Each wheel 5 is mounted on a drive shaft. For ease of description, the front wheel drive shaft is referred to as the front drive shaft 6, and the rear wheel drive shaft is referred to as the rear drive shaft 9. The engine 1 is connected to one of the front drive shafts 6 via the transmission 2, which in turn is connected to the other drive shaft via the disconnect mechanism 3 and the transfer case 4. A set of disconnect mechanisms 3 is mounted on each side of the rear main reducer assembly 8, and each set of disconnect mechanisms 3 is connected to a corresponding rear drive shaft 9. The front wheels are the normal drive wheels, while the rear wheels are the auxiliary drive wheels. Disconnect mechanisms 3 are mounted at strategic locations on the front drive shaft 6 and rear drive shaft 9. The disconnect mechanisms 3 connected to the transfer case 4 control whether power is transmitted to the rear wheels. Disconnect mechanisms 3 on either side of the rear main reducer assembly 8 further control power distribution between the left and right rear wheels, enabling the vehicle to flexibly switch between two-wheel drive and four-wheel drive modes.

[0027] like Figure 2 As shown, the separation mechanism 3 of this embodiment includes a controller 31, an actuator motor 33, a driving mechanism, a separation fork 36, a wedge-shaped movable gear 37, and a wedge-shaped fixed gear 39. A thrust bearing 38 is disposed between the wedge-shaped movable gear 37 and the wedge-shaped fixed gear 39. The wedge-shaped movable gear 37, the thrust bearing 38, and the wedge-shaped fixed gear 39 are all mounted on corresponding drive shafts. The wedge-shaped movable gear 37 is disposed on the side of the transfer case 4 or the rear main reducer assembly 8. A plurality of wedge-shaped teeth 371 are provided on the side of the wedge-shaped movable gear 37 facing the wedge-shaped fixed gear 39. The wedge-shaped teeth 371 are evenly distributed along the circumference of the drive shaft, and groove structures 372 are formed inside the wedge-shaped teeth 371. The wedge-shaped fixed gear 39 has wedge-shaped tooth grooves 391 corresponding one-to-one with the wedge-shaped teeth 371. The wedge-shaped teeth 371 cooperate with the wedge-shaped tooth grooves 391 to achieve precise separation and connection between the two. In this embodiment, the head of the wedge-shaped tooth 371 has a frustum structure, and the wedge-shaped tooth groove 391 has an outward expansion structure adapted to the frustum structure, thereby achieving effective cooperation between the wedge-shaped tooth 371 and the wedge-shaped tooth groove 391 .

[0028] A protrusion 392 is formed on the inner side of the wedge-shaped tooth groove 391. The protrusion 392 is adapted to fit within the groove 372. In this embodiment, the groove 372 has a circular cross-section, and the diameter of the groove 372 matches the diameter of the protrusion 392, allowing the protrusion 392 to be inserted into the groove 372. A thrust bearing 38 is disposed between the groove 372 and the protrusion 392, effectively reducing friction between the wedge-shaped movable gear 37 and the wedge-shaped fixed gear 39. Therefore, the mating arrangement of the wedge-shaped movable gear 37 and the wedge-shaped fixed gear 39, as well as the provision of the thrust bearing 38, reduces friction loss during power transmission and improves transmission efficiency. When switching between two-wheel drive and four-wheel drive modes, power transmission can be quickly and smoothly switched, reducing energy loss.

[0029] An annular groove is provided on the outer side of the wedge-shaped movable gear 37, and a release fork 36 is mounted within the annular groove. A clearance fit is formed between the release fork 36 and the annular groove, enabling the release fork 36 to drive the wedge-shaped movable gear 37 to move axially under the action of the driving mechanism. In this embodiment, the driving mechanism includes an actuator motor 33 and a worm 35. The rotor shaft 34 of the actuator motor 33 is splined to the worm 35. The release fork 36 has a tooth profile on the outer side that matches the worm 35. The release fork 36 and the worm 35 mesh together to form a structure similar to that of a worm gear 35. The actuator motor 33 drives the worm 35 to rotate, and the meshing action of the worm 35 and the release fork 36 causes the wedge-shaped movable gear 37 to move axially. The forward and reverse rotation of the actuator motor 33 causes the wedge-shaped movable gear 37 to move closer to or further away from the wedge-shaped fixed gear 39, thereby separating or engaging the wedge-shaped movable gear 37 with the wedge-shaped fixed gear 39.

[0030] The execution motor 33 is connected to the controller 31 through the wiring harness 32. Figure 2 As shown, controller 31 includes a motor control module, a torque calculation module, and a speed calculation module. The motor control module is used to control the rotation of actuator motor 33, the torque calculation module is used to calculate the output torque of actuator motor 33, and the speed calculation module is used to calculate the rotor speed of actuator motor 33. By controlling the forward or reverse rotation of actuator motor 33, controller 31 drives worm 35 to rotate. The engagement of worm 35 with release fork 36 causes axial movement of release fork 36, thereby driving axial movement of wedge-shaped movable gear 37. Wedge-shaped movable gear 37 is then separated or coupled with wedge-shaped fixed gear 39 via thrust bearing 38, achieving power separation and coupling. Therefore, release mechanism 3 can automatically adjust its operating mode based on the vehicle's real-time driving status.

[0031] In this embodiment, in the two-wheel drive mode, the wedge-shaped movable gear 37 and the wedge-shaped fixed gear 39 are in a separated state, and power is transmitted from the engine 1 to the drive shaft via the transmission 2, and the transfer case 4, the drive shaft 7 and the rear main reducer assembly 8 do not idle; in the four-wheel drive mode, the wedge-shaped movable gear 37 and the wedge-shaped fixed gear 39 are in a coupled state, and power is transmitted from the engine 1 to the transfer case 4 via the transmission 2, and then to the rear main reducer assembly 8 via the drive shaft 7, and finally to the wheels 5.

[0032] The switching mechanism between the four-wheel drive mode and the two-wheel drive mode is as follows: when the speed difference between the front and rear axles tends to be consistent and is less than the set value, the wedge-shaped dynamic gear 37 and the wedge-shaped fixed gear 39 are separated again, the transfer case 4 and the drive shaft 7 and the rear main reduction assembly 8 all stop power transmission, and the vehicle switches back to the two-wheel drive mode.

[0033] The switching between the two-wheel drive and four-wheel drive modes in this embodiment takes into account fuel economy and vehicle passability, while reducing wear and energy loss of the transmission system.

[0034] Example 2: This embodiment further provides a control method for a low fuel consumption four-wheel drive power system. Based on the four-wheel drive power system described in Example 1, the specific control process is as follows: The engine 1 transmits power to the transfer case 4 through the transmission 2 via one of the front drive shafts 6. The separation mechanism 3 connected to the transfer case 4 collects the speed difference signal and the torque signal through the controller 31, controls the execution motor 33 to rotate forward or reverse to drive the worm 35 to rotate, and the worm 35 cooperates with the separation fork 36 to make the separation fork 36 move axially. The separation fork 36 drives the wedge-shaped movable gear 37 to axially displace, and the wedge-shaped movable gear 37 cooperates with the wedge-shaped fixed gear 39 through the thrust bearing 38 to complete the switching of the separation mechanism 3 between engagement and separation, thereby realizing complete separation or engagement of power.

[0035] When the speed difference between the front drive shaft 6 and the rear drive shaft 9 exceeds a certain set value and the speed of the wheel 5 is higher than that of the other wheels 5 (taking the case where the speed of a single right rear wheel is higher than that of the other wheels 5 as an example), the decoupling mechanism 3 at the transfer case 4 engages, and power is transmitted to the transfer case 4 and the drive shaft 7. The decoupling mechanism 3 on the right side of the rear main reducer assembly 8 disengages, and the decoupling mechanism 3 on the left side of the rear main reducer assembly 8 engages, coupling the rear main reducer assembly 8 to the left rear drive shaft 9. The engine 1 inputs power to the transfer case 4 via the transmission 2 via the front drive shaft 6, and then transmits it to the rear main reducer assembly 8 via the drive shaft 7. The rear main reducer assembly 8 then transmits power to the left wheel 5 via the left rear drive shaft 9, achieving complete power separation of the single slipping wheel 5.

[0036] When the speed of the right rear wheel is consistent with that of the other wheels 5, the separation mechanism 3 on the left side of the transfer case 4 and the rear main reduction assembly 8 is also in a separation state. At this time, the vehicle is in a two-wheel drive state, and the transfer case 4, the drive shaft 7 and the rear main reduction assembly 8 do not rotate, thereby realizing timely separation of power. Such reciprocating operation can realize the complete separation and connection process of a single wheel 5 on the rear axle, and set different control strategies according to different vehicle models (the signal processor can float at a set critical point according to the speed to control the separation mechanism 3 to maintain connection for a certain period of time before separation, etc.), so as to prevent the separation mechanism 3 from being completely disconnected when the speed difference of the wheels 5 has not yet been completely consistent, resulting in the vehicle being unable to escape. This can improve the vehicle's passing performance and reduce fuel consumption.

[0037] The switching adjustment between two-wheel drive and four-wheel drive is set according to different road conditions. In this embodiment, on normal urban roads, when the vehicle speed is greater than 20 km / h, the transmission shaft 7, transfer case 4, and rear main reduction assembly 8 do not rotate, and power is only transmitted to the main drive wheels. At this time, the vehicle is in two-wheel drive state; on paved roads, when the vehicle turns, the transmission shaft 7, transfer case 4, and rear main reduction assembly 8 do not rotate when the yaw rate is less than 5 deg / s, and power is only transmitted to the main drive wheels. At this time, it is in two-wheel drive mode; on unpaved roads, when the vehicle speed is less than 30 km / h and the lateral acceleration is less than 0.5 m / s^2, the transmission shaft 7, transfer case 4, and rear main reducer assembly 8 do not rotate, and power is only transmitted to the main drive wheels. At this time, it is a two-wheel drive mode. On snowy roads, when the vehicle speed is less than 30 km / h and the speed difference between the front drive shaft 6 and the rear drive shaft 9 is less than 2%, the transmission shaft 7, transfer case 4, and rear main reducer assembly 8 do not rotate, and power is only transmitted to the main drive wheels. At this time, it is a two-wheel drive mode.

[0038] In order to meet the demand for four-wheel drive under certain working conditions, when the vehicle engine 1 is just started and the speed is less than 20km / h, the transfer case 4 and the rear main reduction assembly 8 are both engaged, and the vehicle is in four-wheel drive state. At this time, the vehicle's starting power is improved and the starting waiting time is reduced; when the vehicle makes a sharp turn, when the vehicle speed is greater than 15km / h and the yaw rate is greater than 5deg / s, the transfer case 4 and the rear main reduction assembly 8 are both engaged to ensure the stability of the vehicle during the sharp turn. When the vehicle speed is less than 30km / h and the front and rear axle speed difference is greater than 2%, the vehicle is in four-wheel drive mode to ensure the vehicle's passability under slippery conditions.

[0039] In this embodiment, the vehicle switches to four-wheel drive mode when starting (speed below 20 km / h), making a sharp turn (speed above 15 km / h and yaw rate above 5 deg / s), or when the speed is below 30 km / h and the front and rear axle speed difference is greater than 2%. This mode improves the vehicle's passability and stability in complex road conditions (such as wet, muddy, and snowy roads).

[0040] Example 3: This embodiment provides a vehicle equipped with the low fuel consumption four-wheel drive system described in Example 1.

[0041] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A low-fuel-consumption four-wheel drive system comprising four wheels mounted on one end of a drive shaft, wherein a transfer case is connected between the drive shafts of two wheels, and a rear main reducer assembly is connected between the drive shafts of the other two wheels. The transfer case and the rear main reducer assembly are connected via a transmission shaft; one of the drive shafts is connected to the engine via a transmission; It is characterized in that One side of the transfer case is connected to a separation mechanism, and both sides of the rear main reduction assembly are connected to separation mechanisms; when the speed difference is less than a set value, the separation mechanism is in a separation state, forming a two-wheel drive mode; when the speed difference is greater than the set value, the separation mechanism is in a connection state, forming a four-wheel drive mode.

2. A low fuel consumption four-wheel drive power system according to claim 1, characterized in that: The separation mechanism includes a wedge-shaped movable gear and a wedge-shaped fixed gear, a thrust bearing is provided between the wedge-shaped movable gear and the wedge-shaped fixed gear, and the outer side of the wedge-shaped movable gear is clearance-matched with the separation shift fork; The separation fork is connected to a pushing mechanism, and the pushing mechanism is used to drive the separation fork to move axially so as to separate or combine the wedge-shaped movable gear and the wedge-shaped fixed gear.

3. A low fuel consumption four-wheel drive power system according to claim 2, characterized in that: One side of the wedge-shaped movable gear is provided with a plurality of wedge-shaped teeth, and the wedge-shaped fixed gear is provided with a wedge-shaped tooth groove matched with the wedge-shaped teeth.

4. The low fuel consumption four-wheel drive power system according to claim 2, characterized in that: The pushing mechanism includes an executing motor and a worm, wherein the executing motor is connected to the worm, and the separating fork is engaged with the worm.

5. The low fuel consumption four-wheel drive power system according to claim 2, characterized in that: The separation mechanism also includes a controller, which includes a motor control module, a torque calculation module, and a speed calculation module. The motor control module is used to control the rotation of the execution motor, the torque calculation module is used to calculate the output torque of the execution motor, and the speed calculation module is used to calculate the speed of the execution motor rotor.

6. A control method for a low fuel consumption four-wheel drive power system according to any one of claims 1 to 5, characterized in that: include: The engine power is transmitted to the transfer case through the transmission and drive shaft. When the speed difference is less than the set value, the release mechanism is in the disengaged state, and the transmission power is directly transmitted to the wheels by the drive shaft. The rear main reduction assembly and the drive shaft are also in the disengaged state, forming a two-wheel drive. When the speed difference exceeds the set value, the separation mechanisms engage, coupling the transfer case to the drive shaft. Power is input from the engine through the transmission and drive shaft into the transfer case, then transmitted to the rear main reduction assembly through the drive shaft, and finally transmitted to the wheels through the drive shaft, forming four-wheel drive.

7. The control method of a low fuel consumption four-wheel drive power system according to claim 6, characterized in that: When the speed difference between the front and rear drive shafts tends to be consistent and is less than the set value, the separation mechanism switches to the separation state, and no power is transmitted between the transfer case and the drive shaft and the rear main reduction assembly, and the system switches to two-wheel drive.

8. The control method of a low fuel consumption four-wheel drive power system according to claim 6, characterized in that: The pushing mechanism drives the separation fork to move axially, causing the wedge-shaped movable gear to undergo axial displacement. The wedge-shaped movable gear cooperates with the wedge-shaped fixed gear through the thrust bearing to realize the switching of the separation mechanism between the engaged state and the separated state.

9. The control method of a low fuel consumption four-wheel drive power system according to claim 6, characterized in that: During two-wheel drive, the transfer case, drive shaft and rear main reducer assembly do not idle.

10. A vehicle, characterized in that: A low fuel consumption four-wheel drive power system as described in any one of claims 1-5 is installed.

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