CN111497590A - A two-speed variable speed drive system for a plug-in hybrid electric vehicle - Google Patents

Abstract

The invention discloses a two-gear variable-speed driving system of a plug-in hybrid electric vehicle, which comprises an engine; a first drive motor; a second drive motor; the transmission comprises a transmission input shafting and a transmission output shafting, wherein the transmission input shafting can be connected with an engine, a first driving motor and a second driving motor and transmits power; the output shaft system of the speed changer is connected with a differential shaft system which can output power to wheels; and power is transmitted between the transmission input shaft system and the transmission output shaft system through the first-gear transmission gear train or the second-gear transmission gear train. The power of the engine and the power of the two motors are coupled through the transmission input shaft system and the transmission output shaft system which are arranged in parallel, so that the power output under different driving modes is realized, the switching between different working modes can be realized according to different working conditions and the electric quantity of the power battery pack, the fuel economy is improved while the power performance of the vehicle is ensured, and the power interruption of gear shifting is avoided.

Description

A two-speed variable speed drive system for a plug-in hybrid vehicle

technical field

The invention relates to the technical field of the drive system of a hybrid electric vehicle, in particular to a two-speed variable-speed drive system of a plug-in hybrid electric vehicle.

Background technique

In the drive system of a hybrid vehicle, the structure of dual motors and engines has pure electric, series and parallel working modes, which can better improve the fuel economy of the engine and make full use of the economic zone of the motor. However, the hybrid system with three power sources has the following shortcomings: 1. According to the working characteristics of the engine, it is difficult to ensure that the engine works in its economic zone for a long time by using a reducer with only one fixed speed ratio from the engine to the wheel; 2. To ensure the driving comfort and power of the vehicle, it is impossible to provide continuous power to the vehicle during the shifting process of the transmission, resulting in the interruption of the shifting power; 3. The engine, clutch, first drive motor, and second drive motor are arranged on the vehicle at the same time And the space requirement of the transmission is large, and the layout is difficult.

SUMMARY OF THE INVENTION

The purpose of the present invention is to solve the above-mentioned deficiencies of the background technology, and to provide a two-speed variable-speed drive system of a plug-in hybrid electric vehicle with high fuel economy, which can continuously provide power for the vehicle and is easy to arrange.

In order to achieve this purpose, the two-speed variable speed drive system of the plug-in hybrid vehicle designed by the present invention includes a first drive motor, a second drive motor and an engine, and is characterized in that: it also includes a drive system that can be connected with the first drive motor. The motor, the second drive motor and the engine are connected to a transmission input shaft system and transmit power, and a transmission output shaft system is connected to the transmission input shaft system and transmits power; The differential shaft system output to the wheel; the transmission power is transmitted between the transmission input shaft system and the transmission output shaft system through the first-speed transmission gear system or the second-speed transmission gear system.

Further, the transmission input shaft system includes a transmission input shaft, a first-speed driving gear and a second-speed driving gear are coaxially sleeved on the transmission input shaft, the transmission output shaft system includes a transmission output shaft, and the transmission output shaft is A first-speed driven gear and a second-speed driven gear are fixed coaxially on the upper part; the first-speed driving gear and the first-speed driven gear mesh with each other to form the first-speed transmission gear train, and the second-speed driving gear and The second-speed driven gears mesh with each other to form the second-speed transmission gear train.

Further, the output shaft of the transmission is coaxially fixed with an output shaft driven gear; the differential shaft system includes a final reduction gear fixed to the differential, and the differential is connected to the wheels; The output shaft driven gear meshes with the final reduction gear.

Further, the output shaft driven gear is located between the first-speed driven gear and the second-speed driven gear.

Further, the transmission input shaft and the transmission output shaft are arranged in parallel.

Further, a synchronizer is provided between the first-speed driving gear and the second-speed driving gear.

Further, the engine and the transmission input shaft are connected through a clutch.

Further, the first drive motor is connected with a first motor reduction gear, and the first motor reduction gear meshes with the first-speed driving gear.

Further, the second drive motor is connected with a second motor reduction gear, and the transmission input shaft is coaxially fixed with a second motor transmission gear that meshes with the second motor reduction gear.

The beneficial effect of the present invention is that the power of the engine and the two motors are coupled through the transmission input shaft system and the output shaft system arranged in parallel, so as to realize the power output under different driving modes, and can realize the power output according to different working conditions and power battery packs. The power is switched between different working modes. Both the engine and the second drive motor have two-speed power options. By switching the gears, both the engine and the motor can work in their respective economic zones, which improves the fuel economy while ensuring the power of the vehicle. During the shifting process of the engine and the motor, the second drive motor can be used to supplement the torque, which avoids the interruption of shifting power and improves the driving performance of the whole vehicle. To sum up, the present invention simplifies the structure of the hybrid drive system, and has the advantages of simple structure, low cost, high transmission efficiency, and easy arrangement.

Description of drawings

1 is a schematic diagram of the structural connection of a two-speed variable-speed drive system of a plug-in hybrid electric vehicle according to the present invention;

Among them, 1-first drive motor, 2-second drive motor, 3-engine, 4-transmission input shaft, 5-first-speed driving gear, 6-first-speed driven gear, 7-second-speed driving gear, 8- Second gear driven gear, 9—transmission output shaft, 10—output shaft driven gear, 11—differential, 12—final reduction gear, 13—wheel, 14—synchronizer, 15—clutch, 16—first motor Reduction gear, 17—second motor reduction gear, 18—second motor transmission gear.

Detailed ways

The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

As shown in Figure 1, the two-speed variable speed drive system of the plug-in hybrid electric vehicle includes a first drive motor 1; a second drive motor 2; an engine 3; 3. The transmission input shaft system that is connected and transmits power and the transmission output shaft system that is connected to the transmission input shaft system and transmits power; the transmission output shaft system is connected with a differential shaft system that can output power to the wheels; The power is transmitted between the transmission output shafts through the first-speed transmission gear train or the second-speed transmission gear train.

The transmission input shaft system includes a transmission input shaft 4, the transmission input shaft 4 is coaxially sleeved with a first-speed driving gear 5 and a second-speed driving gear 7, and the transmission output shaft system includes a transmission output shaft 9, and the transmission output shaft 9 is coaxially fixed. The first-speed driven gear 6 and the second-speed driven gear 8; the first-speed driving gear 5 and the first-speed driven gear 6 mesh with each other to form a first-speed transmission gear train, and the second-speed driving gear 7 and the second-speed driven gear 8 mesh with each other. , to form a second-speed transmission gear train. The transmission input shaft 4 and the transmission output shaft 9 are arranged in parallel. A synchronizer 14 is provided between the first-speed driving gear 5 and the second-speed driving gear 7 . The engine 3 and the transmission input shaft 4 are connected by a clutch 15 .

The output shaft 9 of the transmission is coaxially fixed with an output shaft driven gear 10 ; the output shaft driven gear 10 is located between the first gear driven gear 6 and the second gear driven gear 8 .

The differential gear shaft system includes a final reduction gear 12 fixedly connected to the differential gear 11 , the differential gear 11 is connected to the wheels 13 ; the output shaft driven gear 10 meshes with the final reduction gear 12 .

The first drive motor 1 is connected with a first motor reduction gear 16 , and the first motor reduction gear 16 meshes with the first gear driving gear 5 . The second drive motor 2 is connected with a second motor reduction gear 17 , and the transmission input shaft 4 is coaxially fixed with a second motor transmission gear 18 that meshes with the second motor reduction gear 17 .

The present invention has the following driving modes:

A. Pure electric drive mode:

1. The first drive motor 1 is driven alone: the engine 3 is stopped, the second drive motor 2 is stopped, the clutch 4 is in the connected or disengaged state, and the power output by the first drive motor 1 passes through the first motor reduction gear 16 and the first gear drive gear in turn. 5. First gear driven gear 6 , transmission output shaft 9 , output shaft driven gear 10 , final reduction gear 12 , differential 11 to wheels 13 .

2. The second drive motor 2 drives the first gear alone: the engine 3 is stopped, the first drive motor 1 is idling, the clutch 15 is disengaged, the synchronizer 14 is moved to the left and combined with the first gear drive gear 5, and the power of the second drive motor 2 passes through the first gear in turn. Second motor reduction gear 17, second motor transmission gear 18, transmission input shaft 4, synchronizer 7, first gear driving gear 5, first gear driven gear 6, transmission output shaft 9, output shaft driven gear 10, final reduction gear 12. The differential 11 is finally transmitted to the wheels 13.

3. The second drive motor 2 drives the second gear alone: the engine 3 is stopped, the first drive motor 1 is idling, the clutch 15 is disengaged, the synchronizer 14 is moved to the right and combined with the second gear driving gear 7, and the power output by the second drive motor 2 passes through in sequence The second motor reduction gear 17, the second motor transmission gear 18, the transmission input shaft 4, the synchronizer 14, the second-speed driving gear 7, the second-speed driven gear 8, the transmission output shaft 9, the output shaft driven gear 10, the main reduction Gear 12, differential 11 to wheels 13.

4. The two drive motors jointly drive the first gear: the engine 3 is stopped, the first drive motor 1 and the second drive motor 2 are driven, the clutch 15 is disengaged, the synchronizer 14 is moved to the left and combined with the first gear drive gear 5, the first drive motor 1 The power of the first gear is transmitted to the first gear driving gear 5 through the first motor reduction gear 16, and the power of the second drive motor 2 is transmitted through the second motor reduction gear 17, the second motor transmission gear 18, the transmission input shaft 4, and the synchronizer 14. After the first gear driving gear 5 is superimposed with the torque of the second drive motor 2, it passes through the first gear driven gear 6, the transmission output shaft 9, the output shaft driven gear 10, the main reduction gear 12, the differential 11 to the wheels 13 .

5. The two drive motors jointly drive the second gear: the engine 3 is stopped, the first drive motor 1 and the second drive motor 2 are driven, the clutch 15 is combined, the synchronizer 14 is moved to the right and combined with the second gear drive gear 7, the first drive motor 1 The power of the second drive motor 2 is transmitted to the transmission output shaft 9 through the first motor reduction gear 16, the first-speed driving gear 5, and the first-speed driven gear 6, while the power of the second drive motor 2 passes through the second motor reduction gear 17, the second motor transmission gear 18. The transmission input shaft 4, the synchronizer 14, the second-speed driving gear 7, the second-speed driven gear 8, are transmitted to the transmission output shaft 9, and the power of the two motors is coupled on the transmission output shaft 9, through the output shaft driven gear 10. Final reduction gear 12, differential 11 to wheel 13.

B. Series drive mode

The clutch 15 is engaged, the synchronizer 14 is set to the middle position, the power of the engine 3 is transmitted to the second drive motor 2 through the clutch 15, the transmission input shaft 4, the second motor transmission gear 18, and the second motor reduction gear 17, with the second drive motor 2. Generate electricity to provide electrical energy for the first drive motor 1. If there is excess electrical energy, it will be stored in the power battery. The power of the first drive motor 1 passes through the first motor reduction gear 16, the first gear driving gear 5, and the first gear driven gear. 6. Transmission output shaft 9, output shaft driven gear 10, final reduction gear 12, differential 11 to wheels 13.

C. Pure engine drive mode

1. Pure engine drives the first gear: the clutch 15 is combined, the synchronizer 14 is moved to the left and combined with the first gear driving gear 5, the first drive motor 1 and the second drive motor 2 are in an idling state, the power of the engine 3 is input through the clutch 15, and the transmission is input. Shaft 4, synchronizer 14, first gear driving gear 5, first gear driven gear 6, transmission output shaft 9, output shaft driven gear 10, final reduction gear 12, differential 11 to wheels 13.

2. The second gear driven by the pure engine: the clutch 15 is combined, the synchronizer 14 is moved to the right and combined with the second gear driving gear 7, the first drive motor 1 and the second drive motor 2 are both in an idling state, the power of the engine 3 is input through the clutch 15, and the transmission is input. Shaft 4, synchronizer 14, 2nd gear driving gear 7, 2nd gear driven gear 8, transmission output shaft 9, output shaft driven gear 10, final reduction gear 12, differential 11 to wheels 13.

D. Parallel drive mode

1. The engine 3 and the second drive motor 2 drive the first gear in parallel: the clutch 15 is engaged, the first drive motor 1 is idling, and the synchronizer 14 moves to the left and engages with the first gear drive gear 5 . The power of the engine 3 is transmitted to the transmission input shaft 4 through the clutch 15; at the same time, the power of the second drive motor 2 passes through the second motor reduction gear 17, the second motor transmission gear 18, the transmission input shaft 4, the engine 3 and the second drive motor 2. The power is coupled on the transmission input shaft 4, and then passes through the synchronizer 14, the first gear driving gear 5, the first gear driven gear 6, and is transmitted to the transmission output shaft 9, the output shaft driven gear 10, the final reduction gear 11, and the differential. 11 to wheel 13. During this process, when the output torque of the second drive motor 2 is a positive value, the engine 3 and the second drive motor 2 are jointly driven. If the output torque of the second drive motor 2 is negative, it is the engine 3 and the second drive motor 2. The driving condition of power generation.

2. The engine 3 and the second drive motor 2 drive the second gear in parallel: the clutch 15 is engaged, the first drive motor 1 is idling, and the synchronizer 14 moves to the right and engages with the second gear drive gear 7 . The power of the engine 3 is transmitted to the transmission input shaft 4 through the clutch 15; at the same time, the power of the second drive motor 2 passes through the second motor reduction gear 17, the second motor transmission gear 17, the transmission input shaft 4, the engine 3 and the second drive motor 2. The power is coupled on the transmission input shaft 4, and then passes through the synchronizer 14, the second-speed driving gear 7, the second-speed driven gear 8, and is transmitted to the transmission output shaft 9, the output shaft driven gear 10, the final reduction gear 12, and the differential. 11 to wheel 13. During this process, when the output torque of the second drive motor 2 is a positive value, it is the common driving condition of the engine 3 and the second drive motor 2. If the output torque of the second drive motor 2 is negative, it is the engine 3 and the second drive motor 2. The driving condition of power generation.

3. The engine 3 and the first drive motor 1 are driven in parallel: the clutch 15 is combined, the second drive motor 2 is idling, the synchronizer 14 moves to the left when the first gear of the engine 3 is output, and is combined with the first gear drive gear 5, and the power of the engine 3 passes through the clutch 15, The transmission input shaft 4 and the synchronizer 14 are transmitted to the first gear driving gear 5; at the same time, the power of the first drive motor 1 is transmitted to the first gear driving gear 5 through the first motor reduction gear 16, and the power of the engine 3 and the first driving motor 1 is The first-speed driving gear 5 is superimposed on the first-speed driven gear 6 , the transmission output shaft 9 , the output shaft driven gear 10 , the final reduction gear 12 , and the differential 11 to the wheels 13 .

When the second gear of the engine 3 is output, the synchronizer 14 moves to the right and is combined with the second gear driving gear 7. The power of the engine 3 is transmitted to the transmission output shaft through the clutch 15, the transmission input shaft 4, the second gear driving gear 7, and the second gear driven gear 8. 9; At the same time, the power of the first drive motor 1 passes through the first motor reduction gear 16, the first gear driving gear 5, the first gear driven gear 6, the power of the engine 3 and the first drive motor 1 is coupled on the transmission output shaft 9, and then It is finally transmitted to the wheels 13 through the output shaft driven gear 10 , the final reduction gear 12 , and the differential 11 . During this process, when the output torque of the first drive motor 1 is a positive value, it is the common driving condition of the engine 3 and the first drive motor 1. If the output torque of the first drive motor 1 is a negative value, it is the engine 3 and the first drive motor 1. The driving condition of power generation.

4. The engine 3 and the two drive motors drive the first gear in parallel: the clutch 15 is combined, the first drive motor 1 and the second drive motor 2 are both driven, and the synchronizer 14 moves left to combine with the first gear drive gear 5 . The power of the engine 3 is transmitted to the transmission input shaft 4 through the clutch 15, and the power of the second drive motor 2 is superimposed with the torque of the engine 3 through the second motor reduction gear 17 and the second motor transmission gear 18 to the transmission input shaft 4. The power of the drive motor 1 is transmitted to the first gear drive gear 5 through the first motor reduction gear 16, and is superimposed with the torque of the engine 3 and the second drive motor 2 transmitted through the transmission input shaft 4 and the synchronizer 14, and the torque of the three power sources is regenerated. Through the first gear driven gear 6, it is transmitted to the transmission output shaft 9, the output shaft driven gear 10, the final reduction gear 12, the differential 11 to the wheels 13. During this process, the torques of the first drive motor 1 and the second drive motor 2 are both positive, which occurs in the vehicle's full-throttle acceleration condition.

5. The engine and two motors drive the second gear in parallel: the clutch 15 is combined, the first driving motor 1 and the second driving motor 2 are both driven, and the synchronizer 14 is moved to the right and combined with the second gear driving gear 7 . The power of the engine 3 is transmitted to the transmission input shaft 4 through the clutch 15, and then passes through the synchronizer 14, the second-speed driving gear 7, and the second-speed driven gear 8 to the transmission output shaft 9. At the same time, the power of the first drive motor 1 is decelerated by the first motor. Gear 16, the first gear driving gear 5, the first gear driven gear 6, to the transmission output shaft 9 and the torque of the engine 3 and the second driving motor 2 are superimposed, and the power of the last three power sources passes through the transmission output shaft 9, and the output shaft is driven Gear 10 , final reduction gear 12 , differential 11 , and finally transmitted to wheels 13 . During this process, the torques of the first drive motor 1 and the second drive motor 2 are both positive, which occurs in the vehicle's full-throttle acceleration condition.

E. Energy Feedback Mode

1. Brake feedback of the first drive motor 1: the clutch 15 is disengaged or combined, the transmission is in neutral, the engine 3 and the second drive motor 2 are stopped, and the power of the wheels 13 is transmitted from the differential 11, the final reduction gear 12, and the output shaft. The driving gear 10, the transmission output shaft 9, the first-speed driven gear 6, the first-speed driving gear 5, the first motor reduction gear 16, are transmitted to the first drive motor 1, and the first drive motor 1 performs energy feedback, and the generated power enters the into the power battery pack.

2. The second drive motor 2 first gear brake feedback: the clutch 15 is disengaged, the synchronizer 14 is engaged with the first gear driving gear 5, and the engine 3 is stopped. The power of the wheels 13 passes through the differential 11, the final reduction gear 12, the output shaft driven gear 10, the transmission output shaft 9, the first gear driven gear 6, the first gear driving gear 5, the synchronizer 14, the transmission input shaft 4, the first gear. The second motor drive gear 18, the second motor reduction gear 17, and finally the second drive motor 2, the second drive motor 2 performs energy feedback to charge the power battery.

3. The second drive motor 2 second gear brake feedback: the clutch 15 is disengaged, the synchronizer 14 is engaged with the second gear driving gear 7, the engine 3 is stopped, and the power of the wheels 13 is transmitted from the differential 11, the main reduction gear 12, and the output shaft. The driving gear 10, the transmission output shaft 9, and then transmitted to the second-speed driven gear 8, the second-speed driving gear 7, the synchronizer 14, the transmission input shaft 4, the second motor transmission gear 18, the second motor reduction gear 17, the second The drive motor 2 performs the second gear energy feedback drive to charge the power battery.

F reverse mode

1. Pure electric reverse gear of the first drive motor 1: the clutch 15 is engaged or disengaged, the synchronizer 14 is placed in the middle position, and the engine 3 and the second drive motor 2 are stopped. The first drive motor 1 is driven by reverse positive torque, through the first motor reduction gear 16, the first gear driving gear 5, the first gear driven gear 6, the transmission output shaft 9, the output shaft driven gear 10, the main reduction gear 12, the differential The transmission 11 is finally transmitted to the wheels 13 .

2. The second drive motor 2 first gear pure electric reverse gear: the clutch 15 is disengaged, the synchronizer 14 is engaged with the first gear driving gear 5, and the engine 3 and the first drive motor 1 are idling. The second drive motor 2 is driven by reversed positive torque, through the second motor reduction gear 17, the second motor transmission gear 18, the transmission input shaft 4, the synchronizer 14, the first gear driving gear 5, the first gear driven gear 6, the transmission output The shaft 9 , the output shaft driven gear 10 , the final reduction gear 12 , and the differential 11 are finally transmitted to the wheels 13 .

3. The second gear of the second drive motor 2 is pure electric reverse gear: the clutch 15 is disengaged, the synchronizer 14 is engaged with the second gear drive gear 7, and the engine 3 and the first drive motor 1 are stopped. The second drive motor 2 is driven by a reverse positive torque, and the transmission output is driven by the second motor reduction gear 17, the second motor transmission gear 18, the transmission input shaft 4, the synchronizer 14, the second-speed driving gear 7, and the second-speed driven gear 8. The shaft 9 , the output shaft driven gear 10 , the final reduction gear 12 , and the differential 11 are finally transmitted to the wheels 13 .

4. Tandem drive reversing: the clutch 15 is engaged, and the synchronizer 14 is placed in the middle position. The engine 3 generates electricity and supplies the first drive motor 1 with the second drive motor 2 through the clutch 15, the transmission input shaft 4, the second motor transmission gear 18, and the second motor reduction gear 17, and the first drive motor 1 reverses the positive torque drive. , through the first motor reduction gear 16 , the first gear driving gear 5 , the first gear driven gear 6 , the transmission output shaft 9 , the output shaft driven gear 10 , the main reduction gear 12 , The differential 11 is finally transmitted to the wheels 13 .

G. Stop power generation mode: the clutch 15 is engaged, the synchronizer 14 is in the middle position, the engine 3 takes the second drive motor 2 to generate electricity to charge the power battery, and the first drive motor 1 is in a stopped state.

H. Shifting without power interruption: The shifting process in pure engine driving and parallel driving modes is that the clutch 15 is disengaged, and the synchronizer 14 is set to the middle position. During this process, the first drive motor 1 drives the vehicle to ensure that the power is not interrupted. The power transmission route of a drive motor 1 is the first motor reduction gear 16 , the first gear driving gear 5 , the first gear driven gear 6 , the transmission output shaft 9 , the output shaft driven gear 10 , the final reduction gear 12 , the differential 11 It is finally transmitted to the wheel 13 . The second drive motor 2 is set to the speed control mode, and the speed of the synchronizer 14 is adjusted through the second motor reduction gear 17, the second motor transmission gear 18, and the transmission input shaft 4, so that the synchronizer 14 matches the gear speed of the target gear, That is, the rotational speed of the first-speed driving gear 5 or the second-speed driving gear 7 is the same, and the clutch 15 is engaged after the shifting process of the target gear is completed.

The above descriptions are only preferred embodiments of the present invention, and do not limit the structure of the present invention in any form. Any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solutions of the present invention.

Claims (9)

1. A two-speed variable speed drive system of a plug-in hybrid electric vehicle, comprising a first drive motor (1), a second drive motor (2) and an engine (3), characterized in that: it also includes a A first drive motor (1), the second drive motor (2) and the engine (3) are connected to a transmission input shaft system and transmit power, and a transmission output shaft system is connected to the transmission input shaft system and transmits power ; The transmission output shaft system is connected with a differential shaft system that can output power to the wheels; the transmission input shaft system and the transmission output shaft system are transmitted through a first-speed transmission gear train or a second-speed transmission gear train power. 2. The two-speed variable speed drive system of a plug-in hybrid electric vehicle according to claim 1, wherein the transmission input shaft system comprises a transmission input shaft (4), and the transmission input shaft (4) is the same as the above The shaft sleeve is provided with a first-speed driving gear (5) and a second-speed driving gear (7), the transmission output shaft system includes a transmission output shaft (9), and the transmission output shaft (9) is coaxially fixed with a first-speed driven A gear (6) and a second-speed driven gear (8); the first-speed driving gear (5) and the first-speed driven gear (6) mesh with each other to form the first-speed transmission gear train, the second-speed driving gear The driving gear (7) and the second-speed driven gear (8) mesh with each other to form the second-speed transmission gear train. 3. The two-speed variable speed drive system of a plug-in hybrid electric vehicle according to claim 2, characterized in that: an output shaft driven gear (10) is coaxially fixed on the transmission output shaft (9); The differential gear shaft system comprises a final reduction gear (12) fixedly connected with the differential gear (11), the differential gear (11) is connected to the wheels (13); the output shaft driven gear (10) Mesh with the main reduction gear (12). 4. The two-speed variable speed drive system of a plug-in hybrid electric vehicle according to claim 3, characterized in that: the output shaft driven gear (10) is located between the first-speed driven gear (6) and the Between the second-speed driven gear (8). 5. The two-speed variable speed drive system of a plug-in hybrid electric vehicle according to claim 2, wherein the transmission input shaft (4) and the transmission output shaft (9) are arranged in parallel. 6. The two-speed variable-speed drive system of a plug-in hybrid electric vehicle according to claim 2, wherein a synchronization is provided between the first-speed driving gear (5) and the second-speed driving gear (7) device (14). 7. The two-speed variable speed drive system of a plug-in hybrid vehicle according to claim 2, wherein the engine (3) and the transmission input shaft (4) are connected through a clutch (15). 8. The two-speed variable speed drive system of a plug-in hybrid electric vehicle according to claim 2, characterized in that: the first drive motor (1) is connected with a first motor reduction gear (16), and the first drive motor (1) is connected with a first motor reduction gear (16). The motor reduction gear (16) meshes with the first-speed driving gear (5). 9. The two-speed variable speed drive system of a plug-in hybrid electric vehicle according to claim 2, characterized in that: the second drive motor (2) is connected with a second motor reduction gear (17), and the transmission input A second motor transmission gear (18) meshing with the second motor reduction gear (17) is coaxially fixed on the shaft (4).

Images