Four-wheel-drive multi-gear hybrid power transmission system and vehicle

Abstract

The invention discloses a four-wheel-drive multi-gear hybrid power transmission system which comprises a first drive system and a second drive system which drive two pairs of wheels of a vehicle respectively. Wherein the first driving system comprises an engine, a first motor, an input shaft, a first motor shaft, a first output shaft, a first synchronizer, a second synchronizer and a plurality of gear sets, the input shaft is connected with the engine, the first motor shaft is connected with the first motor, the first synchronizer is connected with the input shaft, and the second synchronizer is connected with the output shaft; matched gear sets are arranged on the input shaft, the first motor shaft and the output shaft to realize transmission connection; the second driving system comprises a second motor, a second motor shaft and a second output shaft. The second motor and the second output shaft are connected directly or through a speed reduction transmission mechanism. According to the system, one motor is omitted, the cost is remarkably reduced, multi-gear switching can be achieved, the fuel consumption economy of an engine is improved, and the system can cope with various working conditions.

Description

Technical Field

[0001] The invention discloses a four-wheel drive multi-speed hybrid power transmission system and a vehicle, belonging to the technical field of automobile power transmission devices. Background Art

[0002] Due to the advantages of hybrid vehicles in energy saving and environmental protection, hybrid vehicles have gradually become a hot development direction in the automotive industry. Among them, four-wheel drive hybrid vehicles are relatively simple in structure compared to traditional fuel four-wheel drive vehicles. The front and rear wheels of four-wheel drive hybrid vehicles are driven by two drive systems respectively, and at least one drive system is a hybrid electric system. Because hybrid four-wheel drive vehicles have strong road applicability, safety, power and other advantages, they are loved by consumers. Among them, the ability to achieve multi-mode hybrid drive is an important indicator of four-wheel drive hybrid vehicles.

[0003] There are three technical routes for the existing two-wheel drive hybrid system: a power split system based on dual-motor planetary gears, a single-motor parallel system, and a dual-motor series-parallel system. Currently, the main dual-motor hybrid architecture is P1+P3 (P1 and P3 indicate the position of the motor, the P1 motor is located on the crankshaft of the engine, and the P3 motor is located behind the gearbox). For example, DMi and DHT set two motors on the same axle. The P1+P3 series-parallel hybrid is superior in structure, low manufacturing cost, and high transmission efficiency. The single-gear structure has excellent smoothness, and the multi-gear structure has better fuel economy. The existing four-wheel drive hybrid system is mostly a three-motor hybrid architecture of P1+P3+P4 (P1, P3, and P4 indicate the position of the motor, the P1 motor is located on the crankshaft of the engine, the P3 motor is located behind the gearbox, and the P4 motor is on the other axle of the car). On the basis of the above-mentioned two-wheel drive hybrid system, a pure electric drive device with a drive motor is added to drive the other axle. The P1+P3+P4 three-motor hybrid architecture includes a dual-motor planetary gear power split system and a dual-motor series-parallel system. The technical ideas of both are to use the electric drive system as the main driving source under medium and low loads, and use the battery pack as an energy "reservoir" to perform "peak shaving and valley filling" operations through generators and motors to avoid low-speed, high-load and other working conditions where traditional gasoline engines have the lowest energy efficiency.

[0004] For example, a dual-motor series-parallel system has a hybrid four-wheel drive system, which consists of an engine, a P1 motor, a P3 motor, and a P4 motor. Its front-drive power system has a short energy transfer path and high mechanical efficiency. The engine can be connected in series and in parallel, which is highly flexible and applicable to a wide range of scenarios. However, the system does not have a shift mechanism and cannot shift gears. The system needs to be matched with a very powerful P3 motor or P4 motor to participate in the drive to ensure the vehicle's power. Otherwise, at a relatively high speed, the driver's power will be very poor if he wants to accelerate again. Matching a high-power P3 motor significantly increases the cost. For another example, the invention patent "CN201610723146.8, a new multi-mode hybrid powertrain system" consists of an engine, a P1+P3 motor, and two rear wheel hub motors. The front-drive module engine and motor have only one gear, and the engine and motor are not efficient. The rear axle of this configuration uses two hub motors. Although it can solve the layout space problem, the cost and technical difficulty are significantly increased.

[0005] Power split systems, such as the THS system four-wheel drive version, adopt a PS+P4 configuration. Looking at the PS (power split) structure alone, the system consists of an engine, generator, and motor coupled together through a planetary gearbox. Since the engine speed is decoupled, the engine speed can be increased at low vehicle speeds, resulting in better fuel economy and power, but the engine torque is not decoupled from the wheel end, making starting control more difficult. Due to the power cycle in the system, the efficiency is low at high vehicle speeds, the generator discharges inefficiently, and the motor charges inefficiently.

[0006] In summary, whether it is a dual-motor series-parallel system or a power split system, a P4 motor must be added to achieve four-wheel drive, which significantly increases the cost. The two motors P1 and P3 perform their respective functions of power generation + direct drive, and neither is indispensable.

[0007] There is a P1+P4 four-wheel drive structure, such as the invention patent "CN202310896432.4, hybrid power drive assembly and automobile", which uses a P1 motor, an engine, several synchronizers, and a gear set as the front drive unit. The rear drive unit uses a single motor + mechanical structure to connect to the wheels. This configuration of the engine and P1 motor has three gears. Compared with the commonly used one-gear gear structure, it can obtain better power and economy, and eliminating a P3 motor can significantly reduce costs. However, its engine and P1 motor are fixedly connected and cannot be decoupled. Four-wheel drive cannot be achieved in the pure electric state, which reduces the scope of application. In addition, there are many components, a complex structure, high cost, large space occupation, and difficult layout. Summary of the invention

[0008] The technical problem to be solved by the present invention is to provide a four-wheel drive four-speed hybrid power transmission system, including a front-wheel drive system and a rear-wheel drive system, wherein the engine drives the front wheels and has four gears, which can improve the fuel economy of the engine; the front-wheel drive system has only one set of motors, which have two gears and well balance large thrust and high speed; the rear-wheel drive system is an electric drive axle, including a rear axle motor and a reduction gear, etc.; most series-parallel hybrid four-wheel drive configurations require three motors (P1+P3+P4), and the power-split four-wheel drive hybrid power system also requires three motors, while the present system only requires two motors, which reduces one motor and significantly reduces the cost, and its structure is simple and compact, and the layout space requirement is small; gear shifting can be achieved without power interruption in EV or HEV working conditions, thereby improving the safety of vehicle driving, the passability on complex roads, the off-road capability and the driving capability on slippery roads; and more gear switching can be achieved, thereby improving the fuel consumption economy of the engine; it is a hybrid full-time four-wheel drive transmission system with a variety of pure electric and hybrid working conditions, which can cope with various working conditions.

[0009] A four-wheel drive multi-speed hybrid power transmission system comprises a front drive system and a rear drive system.

[0010] The front-wheel drive system includes an engine, a front-axle motor, a first motor shaft, an input shaft, a first output shaft, two pairs of synchronizers, and a number of gear sets. The input shaft is connected to the engine; the input shaft is sleeved with two left and right gears, one pair of synchronizers is connected to the input shaft, and the input shaft is connected or disconnected with the left and right gears respectively through the synchronizers. When the synchronizer is hung on the left, it is connected to the left gear, when the synchronizer is hung on the right, it is connected to the right gear, and when the synchronizer is placed in the middle position, it is not connected to the left and right gears; the first output shaft is sleeved with two left and right gears, a pair of synchronizers is connected to the first output shaft, and the first output shaft is connected or disconnected with the left and right gears respectively through the synchronizer; the first motor shaft is connected to the front-axle motor, and the first motor shaft is sleeved with two left and right gears, and the two gears are meshed with the gears on the input shaft and the first output shaft to transmit each other.

[0011] The rear-drive system includes a rear axle motor, a second motor shaft, and a rear output shaft. The rear axle motor and the rear output shaft are directly or through a reduction mechanism connected to the main reduction gear.

[0012] Its front-wheel drive system and rear-wheel drive system are coupled through the ground, and the front-axle motor and the rear-axle motor are electrically connected.

[0013] The gears on the two motor shafts mesh with the gears on the input shaft and the gears on the output shaft at the same time, and the gears on the input shaft and the gears on the output shaft do not mesh with each other; the gears on the two motor shafts include two gears connected as one, one of which meshes with the input shaft gear, and the other meshes with the output shaft gear. This makes it easy to design a suitable speed ratio.

[0014] Alternatively, the gear on the output shaft meshes with the gear on the motor shaft and the gear on the input shaft at the same time, and the gear on the motor shaft and the gear on the input shaft do not mesh with each other; the gear on the output shaft includes two gears connected as one, one of which meshes with the input shaft gear and the other meshes with the motor shaft gear. This makes it easy to design a suitable speed ratio.

[0015] Alternatively, the gear on the input shaft meshes with the gear on the motor shaft and the gear on the output shaft at the same time, and the gear on the motor shaft and the gear on the output shaft do not mesh with each other; the gear on the input shaft includes two gears connected as one, one of which meshes with the output shaft gear and the other meshes with the motor shaft gear. This makes it easy to design a suitable speed ratio.

[0016] Among them, both synchronizers can be replaced by clutches.

[0017] The speed transmission system has any one or more of the following working modes. The front axle motor can only drive the front output shaft, and the rear axle motor can only drive the rear output shaft. The "front output shaft" and "rear output shaft" described below are both described as "output shaft":

[0018] Pure electric mode: The front axle motor or the rear axle motor participates in driving the output shaft and can realize power shifting.

[0019] Series mode: The engine drives the front axle motor to generate electricity, and the rear axle motor drives the output shaft.

[0020] Parallel mode: The engine drives the output shaft through the selected gear, the front axle motor and the rear axle motor can be driven, generated or idle respectively, and power shifting can be achieved.

[0021] The present invention also provides a hybrid vehicle, which comprises the four-wheel drive multi-speed hybrid power transmission system.

[0022] The beneficial effects of the present invention are as follows:

[0023] This design is a hybrid four-wheel drive system with an engine having four gears and full-time four-wheel drive.

[0024] Compared with a simple series-parallel hybrid power system (first gear, second gear, and third gear in the prior art), this design can realize four gears of the engine, which can improve the fuel economy of the engine and enhance the acceleration performance of the whole vehicle; compared with a simple single-gear motor, the front-drive motor of the present invention has two gears, which well balances high thrust and high speed, further reducing costs; the second motor of the rear-drive system can be provided with a reduction mechanism with a moderate speed ratio, which has good thrust and efficiency at medium vehicle speeds.

[0025] Compared with other four-speed four-wheel drive hybrid systems, this design: the speed change mechanism uses parallel shaft gears, which is low in cost; the gear shift mechanism uses synchronizers with high efficiency, low cost and simple operating mechanism, which is conducive to improving vehicle fuel economy and reducing manufacturing costs; only two pairs of synchronizers are needed, compared with the clutch system, the complex hydraulic mechanism is omitted, the number of gear shift actuators is small, which is conducive to reducing costs; it is better than dual-power alternating drive and gear shifting, the gear shift transition time requirement is reduced, the gear shift actuator requirement is reduced, which is conducive to reducing costs; only synchronizers are used as gear shift mechanisms, and the types of gear shift mechanisms are small, which is conducive to reducing costs;

[0026] Compared with the above-mentioned P1+P3+P4 hybrid four-wheel drive system, this design has only two motors, which reduces one motor and significantly reduces costs. The two motors can drive the front and rear axles respectively to maximize efficiency. The motor on the front axle can be decoupled from the engine, and it has two functions of driving and generating electricity (TM / GM). The system can achieve the four-wheel drive function without increasing costs, bringing the experience of four-wheel drive, the price of two-wheel drive, the performance of four-wheel drive, and the energy consumption of two-wheel drive. It has the advantages of good power performance, low fuel consumption, reduced vehicle layout space and significantly reduced costs; the front-wheel drive system has a compact structure and short axial size, which is conducive to promotion and application; the rear-wheel drive system uses only one motor, which is low in cost.

[0027] Compared with the above-mentioned P1+P4 hybrid four-wheel drive system, it uses multiple pairs of parallel shaft gears, planetary gears, clutches and synchronizers, and has a complex mechanical structure. The use of planetary gears increases the difficulty and cost of manufacturing. This system uses a single shift actuator (using only synchronizers), which reduces the control difficulty and eliminates the complex hydraulic shift actuator compared to the system solution that uses both clutches and synchronizers, reducing costs; this system uses fewer parts to achieve four gears, and has a simple structure; the front axle motor of this system can be decoupled from the engine, and four-wheel drive can be achieved under pure electric conditions, which improves the adaptability to road conditions; when the rear axle P4 motor of this system fails, the front axle motor alone can drive the wheels to provide power, which increases the ability to cope with harsh conditions.

[0028] The four-speed hybrid power transmission system described in the present invention has a front axle motor that drags the engine to adjust the speed when the engine shifts gears, and the rear axle motor can provide power to drive the rear axle wheels when the front axle motor drags the engine to adjust the speed, thereby compensating for the power and achieving shifting without power interruption. The process is smooth and the comfort is good, thereby ensuring the smoothness of vehicle driving. The EV (pure electric drive) working condition can also achieve shifting without power interruption through the cooperation of the front and rear axle motors. The process is smooth and the comfort is good. The rear-wheel drive system can cooperate with the front-wheel drive system to enable the car to have a full-time four-wheel drive function and can better adapt to road conditions.

[0029] The mechanical structure of the front axle motor, the rear axle motor and the connected wheels is simple, the transmission path is short, and the braking energy recovery efficiency is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the first embodiment of the present invention.

[0031] Figure 2 It is a schematic diagram of the second embodiment of the present invention.

[0032] Figure 3 It is a schematic diagram of the third embodiment of the present invention. DETAILED DESCRIPTION

[0033] The present invention will be further described below in conjunction with the accompanying drawings:

[0034] See also Figures 1 to 3 , a four-wheel drive multi-speed hybrid power transmission system, comprising a first drive system and a second drive system, wherein

[0035] A first drive system includes an engine, a first motor, an input shaft, a first motor shaft, a first output shaft, a first synchronizer, a second synchronizer, and a plurality of gear sets, wherein the input shaft is connected to the engine, the first motor shaft is connected to the first motor, the first synchronizer is connected to the input shaft, and the second synchronizer is connected to the output shaft. The input shaft, the first motor shaft, and the output shaft are provided with matching gear sets to achieve transmission connection. The input shaft achieves gear switching through the first synchronizer and at least two gears on the input shaft, and the output shaft achieves gear switching through the second synchronizer and at least two gears on the output shaft. The first drive system outputs torque through the first output shaft to provide a front driving force or a rear driving force;

[0036] The second drive system includes a second motor and a second output shaft. The second motor and the second output shaft are connected directly or through a reduction transmission mechanism. The second drive system outputs torque through the second output shaft to provide rear driving force or front driving force.

[0037] The first drive system can be a front drive system or a rear drive system; when the first drive system is used as a front drive system, the second drive system is a rear drive system; when the first drive system is used as a rear drive system, the second drive system is a front drive system. In the following embodiments, the first drive system is used as a front drive system and the second drive system is used as a rear drive system. Specifically, the first motor is also called a front axle motor, the first output shaft is called a front output shaft, the second motor is also called a rear axle motor, the second output shaft is called a rear output shaft, and the others are similar.

[0038] Embodiment 1

[0039] See also Figure 1 As shown, a four-wheel drive multi-speed hybrid power transmission system includes a front-wheel drive system and a rear-wheel drive system.

[0040] The front-wheel drive system includes an engine 1, a first motor 2, an input shaft 4, a first motor shaft 5 (i.e., a transmission shaft), a first output shaft 6 (i.e., a front output shaft), a first synchronizer S1 and a second synchronizer S2. The input shaft 4 is connected to the engine 1, and a first gear A1 and a second gear B1 are sleeved on the input shaft 4. The first synchronizer S1 is connected to the input shaft 4, and the input shaft 4 is connected or disconnected with the first gear A1 or the second gear B1 respectively through the first synchronizer S1. Specifically, according to Figure 1 As shown, when the first synchronizer S1 moves to the left and combines with the first gear A1, the input shaft 4 is connected to the first gear A1; when the first synchronizer S1 moves to the right and combines with the second gear B1, the input shaft 4 is connected to the second gear B1; when the first synchronizer S1 is in the middle position, the input shaft 4 is not connected to the first gear A1 and the second gear B1; the first output shaft 6 is sleeved with the third gear A3 and the fourth gear B3, the second synchronizer S2 is connected to the first output shaft 6, and the first output shaft 6 is connected or not connected to the third gear A3 or the fourth gear B3 respectively through the second synchronizer S2, specifically: according to Figure 1 As shown, when the second synchronizer S2 moves to the left and engages with the third gear A3, the first output shaft 6 is connected to the third gear A3; when the second synchronizer S2 moves to the right and engages with the fourth gear B3, the first output shaft 6 is connected to the fourth gear B3; when the second synchronizer S2 is in the middle position, the first output shaft 6 is not connected to either the third gear A3 or the fourth gear B3.

[0041] The first motor shaft 5 is connected to the shaft of the first motor 2, and the fifth gear A2, the seventh gear A2' and the sixth gear B2 are connected to the first motor shaft 5, and the fifth gear A2 and the seventh gear A2' are connected side by side; the fifth gear A2 is meshed with the first gear A1, the seventh gear A2' is meshed with the third gear A3, and the first gear A1 and the third gear A3 are not meshed with each other; the sixth gear B2 is meshed with the second gear B1 and the fourth gear B3 at the same time, and the second gear B1 and the fourth gear B3 are not meshed with each other.

[0042] The rear-wheel drive system includes a second motor 3, a second motor shaft 7, and a second output shaft 8 (i.e., a rear output shaft). The second motor shaft 7 transmits power to the wheels through a reduction mechanism and a main reducer or other reduction transmission mechanism, wherein the reduction mechanism includes an eighth gear C2 and a ninth gear C3.

[0043] System function table 1

[0044]

[0045] Note: D / G means that the motor is connected to the transmission chain and follows the drive chain, and can be switched to the driving or generating state at any time as needed.

[0046] When the system works in various modes, the components are set as follows:

[0047] EV two-wheel drive mode: the engine 1 is turned off, the first synchronizer S1 and the second synchronizer S2 are disengaged, and the second motor 3 outputs power through the eighth gear C2 on the second motor shaft 7, the ninth gear C3 on the second output shaft 8 and the final reducer. Among them, the reduction mechanism (C3 / C2) has a medium speed ratio, and the medium speed ratio of the second motor is between the two speed ratios of the first motor.

[0048] EV four-wheel drive mode: the engine 1 is turned off, the first synchronizer S1 is disengaged, and the connection with the transmission chain is cut off; the second synchronizer S2 is engaged with the fourth gear B3 (or the third gear A3), and the first motor 2 drives the first output shaft 6 and the front wheels through the gear pair B2 / B3 (or the gear pair A2' / A3), and the second drive system drives the rear wheels to realize the four-wheel drive of the EV four-wheel drive; the first motor 2 has two gears: a large speed ratio B2 / B3 and a small speed ratio A2' / A3 in the present embodiment.

[0049] In HEV series mode, the first synchronizer S1 is in a gear, and the engine 1 is connected to the first motor 2; the second synchronizer S2 is disengaged, and the engine 1 is separated from the first output shaft 6; the engine 1 drives the first motor 2 to generate electricity, and supplies power to the second drive system, and the second drive system drives the corresponding pair of wheels.

[0050] When the HEV four-wheel drive parallel mode is in progress, the first synchronizer S1 is in one gear, the second synchronizer S2 is in one gear, the engine 1 and the first motor 2 drive a pair of wheels through the transmission gear and the first output shaft 6, and the second drive system drives the other pair of wheels. The two synchronizers have two gears respectively, and together form four combinations to constitute the four gears of the engine 1. Specifically: the first synchronizer S1 is shifted to the left and the second synchronizer S2 is shifted to the left (left and left combined gear shift), the engine 1 drives the first output shaft 6 through the first gear A1, the fifth gear A2, the seventh gear A2' and the third gear A3, which is the first gear; the first synchronizer S1 is shifted to the left and the second synchronizer S2 is shifted to the right (left and right combined gear shift), the engine 1 drives the first output shaft 6 through the first gear A1, the fifth gear A2, the sixth gear B 2 and the fourth gear B3 drive the output shaft 6, which is the second gear; the first synchronizer S1 moves right and the second synchronizer S2 moves left (right and left combined gear), the engine 1 drives the first output shaft 6 through the second gear B1, the sixth gear B2, the seventh gear A2' and the third gear A3, which is the third gear; the first synchronizer S1 moves right and the second synchronizer S2 moves right (right and right combined gear), the engine 1 drives the first output shaft 6 through the second gear B1, the sixth gear B2 and the fourth gear B3, which is the fourth gear.

[0051] Shifting without power interruption in four-wheel drive EV operation:

[0052] In the four-wheel drive EV working condition, the first motor 2 shifts from the large speed ratio gear B2 / B3 to the small speed ratio gear A2' / A3: the first motor 2 transfers the load to the second motor 3, and the second motor 3 continues to drive; after the first motor 2 is unloaded, the second synchronizer S2 is shifted to the right gear; the first motor 2 is synchronized, and after the third gear A3 is synchronized with the first output shaft 6, the second synchronizer S2 is shifted to the left gear; the torque distribution is adjusted to complete the gear shift.

[0053] The first motor 2 shifts from the small speed ratio gear A2' / A3 to the large speed ratio gear B2 / B3: the first motor 2 transfers the load to the second motor 3, and the second motor 3 continues to drive; after the first motor 2 is unloaded, the second synchronizer S2 is disengaged from the left gear; the first motor 2 is synchronized, and after the fourth gear B3 is synchronized with the first output shaft 6, the second synchronizer S2 is shifted to the right gear; the torque distribution is adjusted to complete the gear shift.

[0054] It can be seen that in the EV operating condition, when the first motor 2 shifts gears, the second motor 3 is always driving and compensating the torque of the first motor 2, so there is no power interruption during the gear shifting process.

[0055] Four-wheel drive EV mode switching HEV series mode:

[0056] The vehicle can smoothly switch from the four-wheel drive EV mode to the HEV series drive mode:

[0057] Before switching, the four-wheel drive EV working condition is: the engine 1 is shut down, the first synchronizer S1 is disengaged, the second synchronizer S2 is engaged, the first motor 2 drives the first output shaft 6 through the second synchronizer S2 and the corresponding gears, and the second motor 3 drives the second output shaft 8 through the eighth gear C2 and the ninth gear C3.

[0058] Switching process: first, the load of the first motor 2 is transferred to the second motor 3, which continues to drive; then the second synchronizer S2 is disengaged; then after the motors are synchronized, the first synchronizer S1 is engaged to the left; the first motor 2 drags and starts the engine 1 through the gear pair A2 / A1, the first synchronizer S1 and the input shaft 4; then, the engine 1 enters the working state, outputs power, drives the first motor 2 to generate electricity, supplies power to the second motor 3, drives the vehicle, and the system enters the HEV series drive condition.

[0059] The engine 1 of this system has four gears, and the series drive mode is only used when the vehicle speed is very low (within ten kilometers per hour). When the vehicle speed is slightly higher, the system will shift gears and enter parallel drive. Therefore, the working time of the second motor 3 driving is very short.

[0060] HEV series mode switching HEV four-wheel drive parallel mode:

[0061] When the vehicle speed is very low (less than ten kilometers per hour), the system is HEV series drive; as the vehicle speed increases, the system enters HEV four-wheel drive parallel mode. Engine 1 has four gears, that is, engine 1 can be directly driven at four different speed ratios. The operating efficiency of engine 1 is better than that of a series-parallel hybrid system with three gears or less. The first motor 2 has two gears, which can achieve a good balance between acceleration performance and fuel economy. At the same time, the torque and speed requirements are reduced, which is conducive to reducing costs, weight and NVH; the second motor 3 has a medium speed ratio gear, and the torque and speed requirements of the second motor 3 are moderate.

[0062] The HEV series operation mode can smoothly switch to the HEV four-wheel drive parallel first gear: HEV series mode: the first synchronizer S1 is in the left gear, so that the first motor shaft 5 is connected to the input shaft 4, and the engine 1 drives the first motor 2 to generate electricity; the second motor 3 of the rear axle drives the second output shaft 8 through the eighth gear C2 and the ninth gear C3. To switch from the series drive mode to the parallel drive mode, the following steps should be implemented: the second motor 3 of the rear axle continues to drive, and the vehicle has no power interruption; the first motor 2 of the front axle drives the engine 1 to adjust the speed, and when the fourth gear B3 is synchronized with the first output shaft 6, the second synchronizer S2 is in the right gear; then the torque is allocated to enter the first gear parallel drive mode; the engine 1 drives the first output shaft 6 through the input shaft 4, the first gear A1, the fifth gear A2, the seventh gear A2', the third gear A3, the sixth gear B2 and the fourth gear B3, thereby driving the front axle wheels. The second motor 3 of the rear axle drives the second output shaft 8 to output power through the second motor shaft 7, the eighth gear C2 and the ninth gear C3.

[0063] Similarly, the system can be switched from the HEV series drive mode to other HEV four-wheel drive parallel gears.

[0064] Under HEV conditions, shifting without power interruption:

[0065] The system can interrupt gear shifting without power. When shifting gears, engine 1 is unloaded (output torque is reduced to zero); the second motor 3 compensates for the unloading of engine 1 and maintains drive through the eighth gear C2 and the ninth gear C3; after the original gear synchronizer is disengaged, the first motor 2 drives the engine 1 to synchronize; when the new gear gear is synchronized with the relevant shaft, the synchronizer is engaged; then the torque is adjusted to complete the gear shift.

[0066] HEV first gear can be smoothly switched to HEV second gear: engine 1 is unloaded, and second motor 3 increases torque compensation; second motor 3 continues to drive through eighth gear C2 and ninth gear C3, and the vehicle has no power interruption; after engine 1 torque is reduced to zero, S2 right gear can be easily removed; then, first motor 2 drives engine 1 to adjust speed, so that third gear A3 is synchronized with first output shaft 6; then S2 is engaged in left gear, engine 1 drives first output shaft 6 through input shaft 4, first gear A1, fifth gear A2, seventh gear A2' and third gear A3, and engine 1 is engaged in HEV second gear. After engine 1 is engaged in HEV second gear, second motor 3 can choose to work or not work, and can be switched to driving or power generation state at any time according to needs.

[0067] The HEV second gear can be smoothly switched to the HEV third gear: the engine 1 is unloaded, and the second motor 3 increases torque compensation; the second motor 3 continues to drive through the eighth gear C2 and the ninth gear C3, and the vehicle has no power interruption; after the engine torque is reduced to zero, the gear position of the second synchronizer S2 can be easily removed; then, the first motor 2 drives the engine 1 to adjust the speed, so that the first gear A1 is synchronized with the input shaft 4, and then the first synchronizer S1 is engaged in the right gear; then the first motor 2 drives the engine 1 to adjust the speed, so that the fourth gear B3 is synchronized with the first output shaft 6, and then S2 is engaged in the right gear, and the engine drives the first output shaft 6 through the input shaft 4, the second gear B1, the sixth gear B2 and the fourth gear B3, and the engine 1 is engaged in the HEV third gear. After the engine is engaged in the HEV third gear, the second motor 3 can choose to work or not work, and can be switched to the driving or power generation state at any time according to needs.

[0068] The HEV third gear can be smoothly switched to the HEV fourth gear: the engine 1 is unloaded, and the second motor 3 increases torque compensation; the second motor 3 continues to drive through the eighth gear C2 and the ninth gear C3, and the vehicle has no power interruption; after the engine torque is reduced to zero, the second synchronizer S2 right gear can be easily removed; then, the first motor 2 drives the engine 1 to adjust the speed, so that the third gear A3 is synchronized with the first output shaft 6, and then S2 is engaged in the left gear; the engine 1 drives the first output shaft 6 through the input shaft 4, the second gear B1, the sixth gear B2, the seventh gear A2' and the third gear A3, and the engine 1 is engaged in the HEV fourth gear. After the engine is engaged in the HEV fourth gear, the second motor 3 can choose to work or not work, and can be switched to the driving or power generation state at any time according to needs.

[0069] The present invention also provides a hybrid vehicle, which includes the above-mentioned four-wheel drive multi-speed hybrid power transmission system. Since one motor is reduced, the cost is significantly reduced; gear shifting can be achieved without power interruption in EV or HEV working conditions; and more gear switching can be achieved, improving the fuel consumption economy of the engine, and being able to cope with various working conditions.

[0070] Embodiment 2

[0071] like Figure 2 As shown, the hybrid power system of the present invention includes a front-wheel drive system and a rear-wheel drive system. The front-wheel drive system includes: an engine 1, a first motor 2, a parallel shaft gear set, and two pairs of synchronizers required for shifting; the engine 1 has four gears, and the first motor 2 has two gears; the gear switching is realized by two pairs of synchronizers, the type of shifting mechanism is single, the actuating mechanism is simple, and the cost is low; the speed change mechanism composed of parallel shaft gears and synchronizers has mature technology, low production cost, high transmission efficiency, and low energy loss.

[0072] The engine 1 is connected to the input shaft 4, on which the first synchronizer S1, the first gear A1 and the second gear B1 are arranged; when the first synchronizer S1 is engaged to the left, the input shaft 4 is connected to the first gear A1; when the first synchronizer S1 is engaged to the right, the input shaft 4 is connected to the second gear B1.

[0073] The third gear A3, the tenth gear A3', the fourth gear B3 and the second synchronizer S2 are arranged on the first output shaft 6. The third gear A3 and the tenth gear A3' are connected side by side. When the second synchronizer S2 is in the left gear, the first output shaft 6 is connected to the third gear A3 and the tenth gear A3'. When the second synchronizer S2 is in the right gear, the first output shaft 6 is connected to the fourth gear B3, the third gear A3 is meshed with the first gear A1, and the fourth gear B3 is meshed with B1.

[0074] The first motor 2 is connected to the first motor shaft 5; the fifth gear A2 and the sixth gear B2 are arranged on the first motor shaft 5, the fifth gear A2 is meshed with the tenth gear A3', and the sixth gear B2 is meshed with the fourth gear B3.

[0075] The rear-wheel drive system (i.e., the second drive system) includes a second motor 3, a second motor shaft 7, and a second output shaft 8. The second motor shaft 7 transmits power to the wheels through a reduction mechanism and a main reducer or other reduction transmission mechanism, wherein the reduction mechanism includes an eighth gear C2 and a ninth gear C3.

[0076] Similar to the fifth gear A2 and the seventh gear A2' mentioned above, the third gear A3 and the tenth gear A3' are two gears connected side by side. The third gear A3 is meshed with the first gear A1, and the tenth gear A3' is meshed with the fifth gear A2, which makes the speed ratio design of each gear more flexible.

[0077] System function table 2

[0078]

[0079] Note: D / G means that the motor is connected to the transmission chain and follows the drive chain, and can be switched to the driving or generating state at any time as needed.

[0080] When the system works in various modes, the components are set as follows:

[0081] Vehicle pure electric drive EV working conditions:

[0082] EV two-wheel drive mode: the engine 1 is turned off, the first synchronizer S1 and the second synchronizer S2 are disengaged, and the second motor 3 outputs power through the eighth gear C2 on the second motor shaft 7, the ninth gear C3 on the second output shaft 8 and the final reducer.

[0083] EV four-wheel drive mode: the engine 1 is turned off, the first synchronizer S1 is disengaged, and the connection with the transmission chain is cut off; the second synchronizer S2 is engaged with the fourth gear B3 (or the third gear A3), and the first motor 2 drives the first output shaft 6 and the front wheels through the gear pair B2 / B3 (or the gear pair A2' / A3), and the second drive system drives the rear wheels to realize EV four-wheel drive; the first motor 2 has two gears: in this example, a large speed ratio A2 / A3' and a small speed ratio B2 / B3.

[0084] In the HEV series mode, the first synchronizer S1 is in a gear, and the engine 1 is connected to the first motor; the second synchronizer S2 is disengaged, and the engine 1 is separated from the first output shaft 6; the engine 1 drives the first motor 2 to generate electricity, and supplies power to the second drive system, and the second drive system drives the corresponding pair of (rear) wheels;

[0085] In the HEV four-wheel drive parallel mode, the first synchronizer S1 is in one gear, the second synchronizer S2 is in one gear, the engine 1 and the first motor 2 drive a pair of wheels through the transmission gear and the first output shaft 6, and the second drive system drives the other pair of wheels. There are four combinations of the two synchronizer gear states, constituting the four gears of the engine 1, specifically: the first synchronizer S1 moves left and the second synchronizer S2 moves left, and the engine drives the first output shaft 6 through the gear sets A1 and A2, which is the first gear; the first synchronizer S1 moves left and the second synchronizer S2 moves right, and the engine 1 drives the first output shaft 6 through the gear sets A1, A3, A3', A2, B2 and B3, which is the second gear; the first synchronizer S1 moves right and the second synchronizer S2 moves left, and the engine 1 drives the first output shaft 6 through the gear sets B1, B3, B2, A2 and A3', which is the third gear; the first synchronizer S1 moves right and the second synchronizer S2 moves right, and the engine 1 drives the first output shaft 6 through the gear sets B1 and B2, which is the fourth gear.

[0086] EV rear-drive mode: the engine 1 is turned off, the first synchronizer S1 and the second synchronizer S2 are disengaged; the second motor 3 outputs power through the eighth gear C2 on the second motor shaft 7, the ninth gear C3 on the second output shaft 8 and the final reducer. The reduction mechanism (C3 / C2) has a medium speed ratio.

[0087] EV four-wheel drive mode: The first motor 2 and the second motor 3 can jointly drive the output power to the four wheels, and the first motor 2 can have a larger reduction ratio (torque increase ratio), so the torque requirements of the two motors are not large; since the second motor 3 has a medium speed ratio and the first motor 2 has two speed ratios, the speed requirements of the two motors are moderate.

[0088] Shifting without power interruption in four-wheel drive EV operation:

[0089] In the four-wheel drive EV working condition, the first motor 2 shifts from the large speed ratio gear A2 / A3' to the small speed ratio gear B2 / B3: the first motor 2 transfers the load to the second motor 3, and the second motor 3 continues to drive; after the first motor 2 is unloaded, the second synchronizer S2 is disengaged from the left gear; the first motor 2 is synchronized, and after the fourth gear B3 is synchronized with the first output shaft 6, the second synchronizer S2 is shifted to the right gear; the torque distribution is adjusted to complete the gear shift.

[0090] The first motor 2 shifts from the small speed ratio gear B2 / B3 to the large speed ratio gear A2 / A3': the first motor 2 transfers the load to the second motor 3, and the second motor 3 continues to drive; after the first motor 2 is unloaded, the second synchronizer S2 is shifted to the right gear; the first motor 2 is synchronized, and after the tenth gear A3' is synchronized with the first output shaft 6, the second synchronizer S2 is shifted to the left gear; the torque distribution is adjusted to complete the gear shift.

[0091] It can be seen that in the EV operating condition, when the first motor 2 shifts gears, the second motor 3 is always driving and compensating the torque of the first motor 2, so there is no power interruption during the gear shifting process.

[0092] Four-wheel drive EV mode switching HEV series mode:

[0093] The vehicle can smoothly switch from the four-wheel drive EV mode to the HEV series drive mode:

[0094] Before switching, the four-wheel drive EV working condition is: the engine 1 is shut down, the first synchronizer S1 is disengaged, the second synchronizer S2 is engaged, the first motor 2 drives the first output shaft 6 through the second synchronizer S2 and the corresponding gears, and the second motor 3 drives the second output shaft 8 through the eighth gear C2 and the ninth gear C3.

[0095] Switching process: first, the load of the first motor 2 is transferred to the second motor 3, and the latter continues to drive; then the second synchronizer S2 is disengaged; then after the motors are synchronized, the first synchronizer S1 is engaged to the left; the first motor 2 drags and starts the engine 1 through the gear pair A3 / A1, the first synchronizer S1 and the input shaft 4; then, the engine 1 enters the working state, outputs power, drives the first motor 2 to generate electricity, supplies power to the second motor 3, drives the vehicle, and the system enters the HEV series drive condition.

[0096] The engine of this system has four gears, and the series drive mode is only used when the vehicle speed is very low (more than ten kilometers per hour). When the vehicle speed is slightly higher, the system will be in gear and enter parallel drive. Therefore, the working time of the second motor 3 driving is very short.

[0097] HEV series mode switching HEV four-wheel drive parallel mode:

[0098] When the vehicle speed is very low (less than ten kilometers per hour), the system HEV is driven in series; as the vehicle speed increases, the system enters the HEV four-wheel drive parallel mode. Engine 1 has four gears, that is, engine 1 can be directly driven at four different speed ratios. The operating efficiency of engine 1 is better than that of a series-parallel hybrid power system with three gears or less. The first motor 2 has two gears A2 / A3' and B2 / B3, which can achieve a good balance between acceleration performance and fuel economy. At the same time, the torque and speed requirements are reduced, which is conducive to reducing costs, weight and NVH; the second motor 3 has a medium speed ratio, and the torque and speed requirements of the second motor 3 are moderate.

[0099] The HEV series operation mode can be smoothly switched to the HEV four-wheel drive parallel first gear: HEV series mode: the first synchronizer S1 is in the left gear, so that the first output shaft 6 is connected to the input shaft 4, and the engine 1 drives the first motor 2 to generate electricity; the second motor 3 of the rear axle drives the second output shaft 8 through the eighth gear C2 and the ninth gear C3. To switch from the series drive mode to the parallel drive mode, the following steps should be implemented: the second motor 3 of the rear axle continues to drive, and the vehicle has no power interruption; the first motor 2 drives the engine 1 to adjust the speed, so that the third gear A3 is synchronized with the first output shaft 6, and the second synchronizer S2 is in the left gear; then the torque is allocated to enter the first gear parallel drive mode, and the engine 1 drives the first output shaft 6 through the input shaft 4, the first gear A1 and the third gear A3. The second motor 3 of the rear axle drives the second output shaft 8 through the second motor shaft 7, the eighth gear C2, and the ninth gear C3.

[0100] Similarly, the system can be switched from the HEV series drive mode to other HEV four-wheel drive parallel gears.

[0101] Under HEV conditions, shifting without power interruption:

[0102] The system can interrupt gear shifting without power. When shifting gears, engine 1 is unloaded (output torque is reduced to zero); the second motor 3 compensates for the unloading of engine 1 and maintains drive through the eighth gear C2 and the ninth gear C3; after the original gear synchronizer is disengaged, the first motor 2 drives the engine 1 to synchronize; when the new gear gear is synchronized with the relevant shaft, the synchronizer is engaged; then the torque is adjusted to complete the gear shift.

[0103] The HEV first gear can be smoothly switched to the HEV second gear: the engine 1 is unloaded, and the second motor 3 increases torque compensation; the second motor 3 continues to drive through the eighth gear C2 and the ninth gear C3, and the vehicle has no power interruption; after the engine 1 torque is reduced to zero, the left gear of the first synchronizer S1 can be easily removed; then, the first motor 2 drives the engine 1 to adjust the speed, so that the second gear B1 is synchronized with the input shaft 4; then the first synchronizer S1 is engaged in the right gear, and the engine 1 drives the first output shaft 6 through the input shaft 4, the second gear B1, the fourth gear B3, the sixth gear B2, the fifth gear A2 and the tenth gear A3', and the engine 1 is engaged in the HEV second gear. After the engine 1 is engaged in the HEV second gear, the second motor 3 can choose to work or not work, and can be switched to the driving or power generation state at any time according to needs.

[0104] The HEV second gear can be smoothly switched to the HEV third gear: the engine 1 is unloaded, and the second motor 3 increases torque compensation; the second motor 3 continues to drive through the eighth gear C2 and the ninth gear C3, and the vehicle has no power interruption; after the torque of the engine 1 is reduced to zero, the left gear of the second synchronizer S2 can be easily removed; then, the first motor 2 drives the engine 1 to adjust the speed, so that the fourth gear B3 is synchronized with the first output shaft 6, and then the second synchronizer S2 is engaged in the right gear; the engine 1 drives the second output shaft 8 through the second gear B1 and the fourth gear B3 of the input shaft 4, and the engine 1 is engaged in the HEV third gear. After the engine 1 is engaged in the HEV third gear, the second motor 3 can choose to work or not work, and can be switched to the driving or power generation state at any time according to needs.

[0105] The HEV third gear can be smoothly switched to the HEV fourth gear: the engine 1 is unloaded, and the second motor 3 increases torque compensation; the second motor 3 continues to drive through the eighth gear C2 and the ninth gear C3, and the vehicle has no power interruption; after the torque of the engine 1 is reduced to zero, the first synchronizer S1 right gear can be easily removed; then, the first motor 2 drives the engine 1 to adjust the speed, so that the first gear A1 is synchronized with the first output shaft 6, and then the first synchronizer S1 is engaged in the left gear; the engine 1 drives the first output shaft 6 through the input shaft 4, the first gear A1, the third gear A3, the tenth gear A3', the fifth gear A2, the sixth gear B2 and the fourth gear B3, and the engine 1 is engaged in the HEV fourth gear. After the engine is engaged in the HEV fourth gear, the second motor 3 can choose to work or not work, and can be switched to the driving or power generation state at any time according to needs.

[0106] Embodiment 3

[0107] like Figure 3 As shown, the hybrid power system of the present invention includes a front-wheel drive system and a rear-wheel drive system.

[0108] The front-wheel drive system includes: an engine 1, a first motor 2, a parallel shaft gear set, and two pairs of synchronizers required for shifting; the engine 1 has four gears, and the first motor 2 has two gears; the gear switching is achieved by two pairs of synchronizers, the shifting mechanism is of a single type, the actuating mechanism is simple, and the cost is low; the speed change mechanism composed of parallel shaft gears and synchronizers has mature technology, low production cost, high transmission efficiency, and low energy loss.

[0109] The engine 1 is connected to the input shaft 4, on which the first synchronizer S1, the first gear A1, the eleventh gear A1' and the second gear B1 are arranged, wherein the first gear A1 and the eleventh gear A1' are fixedly connected; when the first synchronizer S1 is shifted to the left, the input shaft 4 is connected to the first gear A1 / A1'; when the first synchronizer S1 is shifted to the right, the input shaft 4 is connected to the second gear B1.

[0110] The third gear A3, the fourth gear B3 and the second synchronizer S2 are arranged on the first output shaft 6. When the second synchronizer S2 is in the left gear, the first output shaft 6 is connected to the third gear A3. When the second synchronizer S2 is in the right gear, the first output shaft 6 is connected to the fourth gear B3. The third gear A3 is meshed with the eleventh gear A1', and the fourth gear B3 is meshed with the second gear B1;

[0111] The first motor 2 is connected to the first motor shaft 5; the fifth gear A2 and the sixth gear B2 are arranged on the first motor shaft 5, the fifth gear A2 is meshed with the first gear A1, and the sixth gear B2 is meshed with the second gear B1.

[0112] Second driving system: The second motor 3 outputs power through the eighth gear C2 on the second motor shaft 7, the ninth gear C3 on the second output shaft 8 and the main reducer. The reduction mechanism C3 / C2 has a medium speed ratio.

[0113] System function table 3

[0114]

[0115]

[0116] Note: D / G means that the motor is connected to the transmission chain and follows the drive chain, and can be switched to the driving or generating state at any time as needed.

[0117] When the system works in various modes, the components are set as follows:

[0118] EV two-wheel drive mode: the engine 1 is turned off, the first synchronizer S1 and the second synchronizer S2 are disengaged, and the second motor 3 outputs power through the eighth gear C2 on the second motor shaft 7, the ninth gear C3 on the second output shaft 8 and the final reducer. The reduction mechanism (C3 / C2) has a medium speed ratio, and the medium speed ratio of the second motor 3 is between the two speed ratios of the first motor 2.

[0119] EV four-wheel drive mode: the engine 1 is turned off, the first synchronizer S1 is disengaged, and the connection with the transmission chain is cut off; the second synchronizer S2 is engaged with the fourth gear B3 (or the third gear A3), and the first motor 2 drives the first output shaft 6 and the front wheels through the gear pair B2 / B3 (or the gear pair A2' / A3), and the second drive system drives the rear wheels to realize EV four-wheel drive; the first motor 2 has two gears: a large speed ratio B3 / B2 and a small speed ratio A2 / A1 / A1' / A3 as in the present embodiment.

[0120] In the HEV series mode, the first synchronizer S1 is in a gear, and the engine 1 is connected to the first motor 2; the second synchronizer S2 is disengaged, and the engine 1 is separated from the first output shaft 6; the engine 1 drives the first motor 2 to generate electricity, and supplies power to the second drive system, and the second drive system drives the corresponding pair of (rear) wheels;

[0121] In the HEV four-wheel drive parallel mode, the first synchronizer S1 is in one gear, the second synchronizer S2 is in one gear, the engine 1 and the first motor 2 drive a pair of wheels through the transmission gear and the first output shaft 6, and the second drive system drives the other pair of wheels. There are four combinations of the two synchronizer gear engagement states, constituting the four gears of the engine 1, specifically: the first synchronizer S1 moves left and the second synchronizer S2 moves left, and the engine 1 drives the first output shaft 6 through the gear sets A1' and A3, which is the first gear; the first synchronizer S1 moves left and the second synchronizer S2 moves right, and the engine 1 drives the first output shaft 6 through the gear sets A1, A2, B2, B1 and B3, which is the second gear; the first synchronizer S1 moves right and the second synchronizer S2 moves left, and the engine 1 drives the first output shaft 6 through the gear sets B1, B2, A2, A1, A1' and A3, which is the third gear; the first synchronizer S1 moves right and the second synchronizer S2 moves right, and the engine 1 drives the first output shaft 6 through the gear sets B1 and B3, which is the fourth gear.

[0122] Vehicle pure electric drive EV working conditions:

[0123] Rear-drive EV mode: the engine 1 is turned off, the first synchronizer S1 and the second synchronizer S2 are disengaged, and the second motor 3 drives the wheels through the eighth gear C2 on the second motor shaft 7, the ninth gear C3 on the second output shaft 8 and the differential or reduction mechanism. The eighth gear C2 and the ninth gear C3 cooperate to form a medium speed ratio.

[0124] EV four-wheel drive mode: the engine 1 is turned off, the first synchronizer S1 is disengaged, and the connection between the engine 1 and the first output shaft 6 is cut off; the second synchronizer S2 is engaged in one of the gears, the first motor 2 drives the first output shaft 6 through the gear-related gears, and the second motor 3 drives the second output shaft 8 through the eighth gear C2 and the ninth gear C3, thereby realizing four-wheel drive.

[0125] Shifting without power interruption in four-wheel drive EV operation:

[0126] In the four-wheel drive EV operating condition, the first motor 2 shifts from a large speed ratio EV I to a small speed ratio EV III: the first motor 2 transfers the load to the second motor 3, and the second motor 3 continues to drive; after the first motor 2 is unloaded, the second synchronizer S2 is disengaged from the right gear; the first motor 2 is synchronized, and after the third gear A3 is synchronized with the first output shaft 6, the second synchronizer S2 is shifted to the left gear; the torque distribution is adjusted to complete the gear shift.

[0127] The first motor 2 shifts from a small speed ratio EVIII to a large speed ratio EV I: the first motor 2 transfers the load to the second motor 3, and the second motor 3 continues to drive; after the second motor 2 is unloaded, the second synchronizer S2 is disengaged from the left gear; the first motor 2 is synchronized, and after the fourth gear B3 is synchronized with the first output shaft 6, the second synchronizer S2 is shifted to the right gear; the torque distribution is adjusted to complete the gear shift.

[0128] It can be seen that in the EV operating condition, when the first motor 2 shifts gears, the second motor 3 is always driving and compensating the torque of the first motor 2, so there is no power interruption during the gear shifting process.

[0129] Four-wheel drive EV mode switching HEV series mode:

[0130] The vehicle can smoothly switch from the four-wheel drive EV mode to the HEV series drive mode:

[0131] Before switching, the four-wheel drive EV working condition is: the engine 1 is shut down, the first synchronizer S1 is disengaged, the second synchronizer S2 is engaged, the first motor 2 drives the first output shaft 6 through the second synchronizer S2 and the corresponding gears, and the second motor 3 drives the second output shaft 8 through the eighth gear C2 and the ninth gear C3.

[0132] Switching process: first, the load of the first motor 2 is transferred to the second motor 3, which continues to drive; then the second synchronizer S2 is disengaged; then after the motors are synchronized, the first synchronizer S1 is engaged to the right; the first motor 2 drags and starts the engine 1 through the gear pair B2 / B1, the first synchronizer S1 and the input shaft 4; then, the engine 1 enters the working state, outputs power, drives the first motor 2 to generate electricity, supplies power to the second motor 3, drives the vehicle, and the system enters the HEV series drive condition.

[0133] The engine of this system has four gears, and the series drive mode is only used when the vehicle speed is very low (more than ten kilometers per hour). When the vehicle speed is slightly higher, the system will be in gear and enter parallel drive. Therefore, the working time of the second motor 3 driving is very short.

[0134] HEV series mode switching HEV four-wheel drive parallel mode:

[0135] When the vehicle speed is very low (less than ten kilometers per hour), the system HEV series drive; as the vehicle speed increases, the system enters the HEV four-wheel drive parallel mode. Engine 1 has four gears, that is, engine 1 can be directly driven at four different speed ratios. The operating efficiency of engine 1 is better than that of a series-parallel hybrid power system with three gears or less. The first motor 2 has two gears, which can achieve a good balance between acceleration performance and fuel economy. At the same time, the torque and speed requirements are reduced, which is conducive to reducing costs, weight and NVH; the second motor 3 has a medium speed ratio, and the torque and speed requirements of the second motor 3 are moderate.

[0136] The HEV series operation mode can be smoothly switched to the HEV first gear: HEV series mode: the first synchronizer S1 is in the left gear, so that the first motor shaft 5 is connected to the input shaft 4, and the engine 1 drives the first motor 2 to generate electricity; the second motor 3 of the rear axle drives the second output shaft 8 through the eighth gear C2 and the ninth gear C3. To switch from the series drive mode to the parallel drive mode, the following steps should be implemented: the second motor 3 of the rear axle continues to drive, and the vehicle has no power interruption; the first motor 2 of the front axle drives the engine 1 to adjust the speed, so that the third gear A3 is synchronized with the second output shaft 8, and the second synchronizer S2 is in the left gear; then the torque is allocated to enter the first gear parallel drive mode (i.e. HEV first gear); the engine 1 drives the first output shaft 6 through the first output shaft 6, the first gear A1 and the third gear A3. The second motor 3 of the rear axle drives the second output shaft 8 through the second motor shaft 7, the eighth gear C2 and the ninth gear C3.

[0137] Similarly, the system can be switched from the HEV series drive mode to other HEV four-wheel drive parallel gears.

[0138] Under HEV conditions, shifting without power interruption:

[0139] The system can interrupt gear shifting without power. When shifting gears, engine 1 is unloaded (output torque is reduced to zero); the second motor 3 compensates for the unloading of engine 1 and maintains drive through the eighth gear C2 and the ninth gear C3; after the original gear synchronizer is disengaged, the first motor 2 drives the engine 1 to synchronize; when the new gear gear is synchronized with the relevant shaft, the synchronizer is engaged; then the torque is adjusted to complete the gear shift.

[0140] The HEV first gear can be smoothly switched to the HEV second gear: the engine 1 is unloaded, and the second motor 3 increases torque compensation; the second motor 3 continues to drive through the eighth gear C2 and the ninth gear C3, and the vehicle has no power interruption; after the torque of the engine 1 is reduced to zero, the left gear of the second synchronizer S2 can be easily removed; then, the first motor 2 drives the engine 1 to adjust the speed, so that the fourth gear B3 is synchronized with the first output shaft 6; then the second synchronizer S2 is engaged in the right gear, and the engine 1 drives the first output shaft 6 through the input shaft 4, the first gear A1, the fifth gear A2, the sixth gear B2, the second gear B1 and the fourth gear B3, and the engine 1 is engaged in the HEV second gear. After the engine 1 is engaged in the HEV second gear, the second motor 3 can choose to work or not work, and can be switched to the driving or power generation state at any time according to needs.

[0141] The HEV second gear can be smoothly switched to the HEV third gear: the engine 1 is unloaded, and the second motor 3 increases torque compensation; the second motor 3 continues to drive through the eighth gear C2 and the ninth gear C3, and the vehicle has no power interruption; after the torque of the engine 1 is reduced to zero, the first synchronizer S1 left gear can be easily removed; then, the first motor 2 drives the engine 1 to adjust the speed, so that the second gear B1 is synchronized with the input shaft 4, and then the first synchronizer S1 is engaged in the right gear; the engine 1 drives the first output shaft 6 through the input shaft 4, the second gear B1 and the fourth gear B3, and the engine 1 is engaged in the HEV third gear. After the engine 1 is engaged in the HEV third gear, the second motor 3 can choose to work or not work, and can be switched to the driving or power generation state at any time according to needs.

[0142] The HEV third gear can be smoothly switched to the HEV fourth gear: the engine 1 is unloaded, and the second motor 3 increases torque compensation; the second motor 3 continues to drive through the eighth gear C2 and the ninth gear C3, and the vehicle has no power interruption; after the torque of the engine 1 is reduced to zero, the right gear of the second synchronizer S2 can be easily removed; then, the first motor 2 drives the engine 1 to adjust the speed, so that the third gear A3 is synchronized with the first output shaft 6, and then the second synchronizer S2 is engaged in the left gear; the engine 1 drives the first output shaft 6 through the input shaft 4, the second gear B1, the sixth gear B2, the fifth gear A2, the first gear A1 and the third gear A3, and the engine 1 is engaged in the HEV fourth gear. After the engine 1 is engaged in the HEV fourth gear, the second motor 3 can choose to work or not work, and can be switched to the driving or power generation state at any time according to needs.

[0143] The above records are only embodiments of the present invention. Any modification or change made by a person familiar with the present technology using the present invention shall fall within the patent scope claimed by the present invention and shall not be limited to those disclosed in the embodiments.

Claims

1. A four-wheel drive multi-speed hybrid power transmission system, characterized in that: It includes a first drive system and a second drive system, wherein A first drive system includes an engine, a first motor, an input shaft, a first motor shaft, a first output shaft, a first synchronizer, a second synchronizer, and a plurality of gear sets, wherein the input shaft is connected to the engine, the first motor shaft is connected to the first motor, the first synchronizer is connected to the input shaft, the second synchronizer is connected to the output shaft, the input shaft, the first motor shaft, and the first output shaft are provided with matching gear sets to achieve transmission connection, the input shaft achieves gear switching through the first synchronizer and at least two gears on the input shaft, the first output shaft achieves gear switching through the second synchronizer and at least two gears on the first output shaft, at least two gears are arranged on the first motor shaft, and the first drive system outputs torque through the first output shaft to provide a front driving force or a rear driving force; The second drive system includes a second motor, a second motor shaft, and a second output shaft. The second motor and the second output shaft are connected directly or through a reduction transmission mechanism. The second drive system outputs torque through the second output shaft to provide rear driving force or front driving force.

2. The four-wheel drive multi-speed hybrid power transmission system according to claim 1, characterized in that: The input shaft is sleeved with a left gear and a right gear, and the input shaft is connected or disconnected with the left gear and the right gear on the input shaft respectively through a first synchronizer; The first output shaft is sleeved with a left gear and a right gear, and the first output shaft is connected or disconnected with the left gear and the right gear on the first output shaft respectively through a second synchronizer; The first motor shaft is provided with a left gear and a right gear, and the two gears are meshed with corresponding gears on the input shaft and / or the first output shaft for mutual transmission.

3. The four-wheel drive multi-speed hybrid power transmission system according to claim 2, characterized in that: The first motor shaft is arranged between the input shaft and the first output shaft, forming a parallel shaft system with the input shaft, the first motor shaft and the first output shaft arranged from one side to the other side, wherein the left gear on the first motor shaft is two gears connected side by side, which are respectively meshed with the left gears on the input shaft and the first output shaft, and the right gear on the first motor shaft is respectively meshed with the right gears on the input shaft and the first output shaft.

4. The four-wheel drive multi-speed hybrid power transmission system according to claim 2, characterized in that: The first motor shaft is arranged behind the first output shaft, forming a parallel shaft system of the input shaft, the first output shaft, and the first motor shaft from one side to the other; wherein the left gear on the first output shaft is two gears connected side by side, which are respectively meshed with the left gears on the input shaft and the first motor shaft, and the right gear on the first output shaft is respectively meshed with the right gears on the input shaft and the first motor shaft.

5. The four-wheel drive multi-speed hybrid power transmission system according to claim 2, characterized in that: The first motor shaft is arranged in front of the input shaft, forming a parallel shaft system of the first motor shaft, the input shaft, and the first output shaft from one side to the other; wherein the left gear on the input shaft is two gears connected side by side, which are respectively meshed with the left gears on the first motor shaft and the first output shaft, and the right gear on the first input shaft is respectively meshed with the corresponding gears on the first motor shaft and the first output shaft.

6. The four-wheel drive multi-speed hybrid power transmission system according to any one of claims 3 to 5, characterized in that: It includes multiple driving modes, namely EV two-wheel drive mode, EV four-wheel drive mode, HEV series mode and HEV four-wheel drive parallel mode; In the EV two-wheel drive mode, the engine is turned off, the first synchronizer is disengaged, the second synchronizer is disengaged, and the second motor drives the second output shaft to output power through the gear set; In EV four-wheel drive mode, the engine is turned off and the first synchronizer is disengaged; the second synchronizer is engaged in one of the gears, the first motor drives the first output shaft through the gear set to drive a pair of wheels, and the second drive system drives the other pair of wheels; In the HEV series mode, the first synchronizer is in a gear, and the engine is connected to the first motor; the second synchronizer is disengaged, and the engine is separated from the first output shaft; the engine drives the first motor to generate electricity, and supplies power to the second drive system, and the second drive system drives the corresponding pair of wheels; When the HEV four-wheel drive parallel mode is in operation, the first synchronizer is in one gear and the second synchronizer is in one gear. The engine and the first motor drive a pair of wheels through the gear set and the first output shaft, and the second drive system drives another pair of wheels. The two synchronizers have two gears respectively, and together they form four combinations to constitute the four gears of the engine.

7. A hybrid vehicle, characterized in that: A four-wheel drive multi-speed hybrid power transmission system comprising any one of claims 1 to 6.

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