CN114789652A

CN114789652A - Hybrid power driving system and vehicle

Info

Publication number: CN114789652A
Application number: CN202110097493.5A
Authority: CN
Inventors: 景枫; 刘庆阳; 孙国庆; 刘野; 韩锋; 单红艳
Original assignee: Great Wall Motor Co Ltd
Current assignee: Great Wall Motor Co Ltd
Priority date: 2021-01-25
Filing date: 2021-01-25
Publication date: 2022-07-26
Anticipated expiration: 2041-01-25
Also published as: CN114789652B

Abstract

The present disclosure relates to a hybrid drive system and a vehicle. The system comprises an engine, a transmission and a driving motor, wherein the transmission comprises a first input shaft, a second input shaft, an output shaft, a first gear set, a second gear set, a first clutch and a second clutch, the output shaft is used for transmitting power to wheels, the first gear set comprises a first driving gear carried by the first input shaft and a first driven gear carried by the output shaft, the second gear set comprises a second driving gear carried by the second input shaft and a second driven gear carried by the output shaft, the first clutch is arranged between the output shaft and the first input shaft of the engine and used for connecting or disconnecting the power transmission between the engine and the first gear set, the second clutch is arranged between the output shaft and the second input shaft of the engine and used for connecting or disconnecting the power transmission between the engine and the second gear set, the drive motor is connected with the first input shaft or the output shaft.

Description

Hybrid power driving system and vehicle

Technical Field

The present disclosure relates to the field of vehicle technologies, and in particular, to a hybrid drive system and a vehicle equipped with the hybrid drive system.

Background

At present, people in the world face two challenges of energy shortage and environmental deterioration, the traditional automobile is increasingly seriously puzzled by oil crisis, and energy conservation and environmental protection gradually become the development theme of the automobile industry. In recent years, hybrid vehicles having two different power sources to achieve reduction in fuel consumption and emission have been developed and put into commercial production and brought to the market.

The power transmission system of the hybrid vehicle may be generally classified into a single mode type and a multi mode type according to a driving mode, wherein the multi mode type power transmission system is receiving attention of a designer due to various advantages such as high power transmission efficiency or rational layout optimization. Many advantages of the hybrid system depend on the connection relationship of the engine, the driving motor, the transmission, the torque transmitting device, and the like, and thus, the design of the connection structure for the power transmission system of the hybrid vehicle is also under constant investigation.

Disclosure of Invention

It is a first object of the present disclosure to provide a hybrid drive system capable of achieving a plurality of drive modes.

In order to achieve the above object, the present disclosure provides a hybrid drive system including:

an engine;

a transmission, the transmission comprising:

a first input shaft to which an output shaft of the engine is coaxially connected;

the second input shaft is coaxially sleeved with the first input shaft;

the output shaft is arranged in parallel with the first input shaft and is used for transmitting power to wheels;

a first gear gearset comprising a first drive gear carried by the first input shaft and a first driven gear carried by the output shaft;

a second gear set having a different gear ratio than the first gear set, the second gear set including a second drive gear carried by the second input shaft and a second driven gear carried by the output shaft;

a dual clutch module, the dual clutch module comprising:

a first clutch provided between an output shaft of the engine and the first input shaft for engaging or disengaging power transmission between the engine and the first gear gearset;

a second clutch provided between an output shaft of the engine and the second input shaft for engaging or disengaging power transmission between the engine and the second gear set;

a driving motor connected with the first input shaft or the output shaft to output power to the output shaft.

Optionally, the hybrid drive system further comprises a generator connected to an output shaft of the engine through a generator output gear set, such that the engine can drive the generator to generate electricity.

Optionally, the transmission further comprises:

a third gear set having a different gear ratio than the first and second gear sets, respectively, the third gear set including a third driving gear carried by the second input shaft and a third driven gear carried by the output shaft;

a synchronizer axially slidably disposed on the second input shaft and located between the second and third gear sets to selectively engage with the second gear set or with the third gear set.

Optionally, a transmission ratio of the first gear set is greater than a rotation ratio of the second gear set, and a transmission ratio of the second gear set is greater than a transmission ratio of the third gear set.

Optionally, the driving motor is coaxially connected with the first input shaft and outputs power to the output shaft through the first gear set.

Optionally, the hybrid drive system further comprises a power output portion, the power output portion comprises an output gear and a differential, the output gear is respectively connected with the output shaft and the differential, and the differential is connected with the wheels.

Optionally, a disconnecting mechanism is arranged between the driving motor and the first gear set, and is used for engaging or disconnecting power transmission between the driving motor and the first gear set.

Optionally, a damper is provided on the output shaft of the engine.

Optionally, the hybrid drive system further comprises a speed sensing means for monitoring a speed difference between the output shaft of the engine and the first input shaft and/or a speed difference between the output shaft of the engine and the second input shaft.

It is a second object of the present disclosure to provide a vehicle including the hybrid drive system described above.

According to the hybrid power drive system, the engine, the drive motor and the two clutches are arranged, so that multiple drive modes are considered, for example, a pure electric drive mode, an engine direct drive mode with different gears, a range extending mode, a hybrid drive mode with different gears, an energy recovery mode, a parking power generation mode and the like can be realized. And secondly, due to the realization of multi-gear power output, the engine can be ensured to be always kept in a high-efficiency area, and the oil consumption of the whole vehicle is reduced. At the in-process of shifting, compensate power through driving motor, can also guarantee to shift the in-process power and not break off, ensure the ride comfort that keeps off the position and switch.

Additional features and advantages of the present disclosure will be set forth in the detailed description which follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure without limiting the disclosure. In the drawings:

FIG. 1 is a schematic block diagram illustration of a hybrid drive system provided in an exemplary embodiment of the present disclosure;

FIG. 2 is a power transfer schematic of a hybrid drive system in a purely electric drive mode provided by an exemplary embodiment of the present disclosure;

3a-3c are power transfer schematic diagrams of a hybrid drive system provided in an exemplary embodiment of the present disclosure in an engine direct drive mode;

FIG. 4 is a power transmission schematic diagram of a hybrid drive system in an energy recovery mode provided by an exemplary embodiment of the present disclosure;

FIG. 5 is a schematic power transmission diagram of a hybrid drive system in an idle charge mode provided in an exemplary embodiment of the present disclosure;

FIG. 6 is a power transfer schematic of a hybrid drive system provided in an exemplary embodiment of the present disclosure in a range extended mode;

7a-7b are power transmission schematics of a hybrid drive system in a hybrid drive mode provided by an exemplary embodiment of the present disclosure.

Description of the reference numerals

1-engine, 2-driving motor, 3-generator, 4-first input shaft, 5-second input shaft, 6-output shaft, 7-first driving gear, 8-first driven gear, 9-second driving gear, 10-second driven gear, 11-third driving gear, 12-third driven gear, 13-first clutch, 14-second clutch, 15-synchronizer, 16-power output part, 161-output gear, 162-differential, 17-shock absorber. 18-generator output gear set.

Detailed Description

The following detailed description of specific embodiments of the present disclosure is provided in connection with the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present disclosure, are given by way of illustration and explanation only, not limitation.

As shown in fig. 1 to 7b, the present disclosure is directed to providing a hybrid driving system that can be used in an oil-electric hybrid or an electric plug-in hybrid system. Comprising an engine 1, a transmission and a drive motor 2. The engine 1 and the driving motor 2 can respectively transmit power to wheels through a transmission so as to drive the vehicle to run. The transmission comprises a first input shaft 4, a second input shaft 5, an output shaft 6, a first gear set, a second gear set and a double clutch module, wherein the double clutch module comprises a first clutch 13 and a second clutch 14. The first input shaft 4 is coaxially connected with an output shaft of the engine 1, the second input shaft 5 is coaxially sleeved with the first input shaft 4, and the output shaft 6 is arranged in parallel with the first input shaft 4 and used for transmitting power to wheels. The first gear set comprises a first driving gear 7 carried by the first input shaft 4 and a first driven gear 8 carried by the output shaft 6, and the second gear set comprises a second driving gear 9 carried by the second input shaft 5 and a second driven gear 10 carried by the output shaft 6, wherein the first gear set and the second gear set have different transmission ratios, and the transmission ratios enable the first gear set and the second gear set to have different output torques or rotating speeds, which can be used as a theoretical basis for realizing different gear switching.

The first clutch 13 and the second clutch 14 in the dual clutch module may be integrated, for example, provided on the same housing or carrier. The output shaft of the engine 1 is connected to the housing or frame, the first clutch 13 is connected to the first input shaft 4, and the second clutch 14 is connected to the second input shaft 5. When the engine 1 works, the power can be transmitted to the shell or the frame body of the double-clutch module. When the first clutch 13 is engaged, the power of the engine 1 is transmitted from the housing or the frame to the first clutch 13, and then the power of the engine 1 is transmitted to the first input shaft 4; when the second clutch 14 is engaged, the power of the engine 1 is transmitted from the housing or the carrier to the second clutch 14, and the power of the engine 1 is transmitted to the second input shaft 5.

The drive motor 2 can be connected either to the first input shaft 4 or to the output shaft 6 for outputting power to the output shaft 6, in other words, it differs in whether the drive motor 2 drives the output shaft 6 directly or indirectly. Fig. 1 shows an exemplary embodiment in which the drive motor 2 is indirectly connected to the output shaft 6 via a first gear wheel set. Specifically, the driving motor 2 is connected to the first input shaft 4, and when the driving motor 2 works, the driving motor can drive the first driving gear 7 carried on the first input shaft 4 to rotate, so as to transmit power to the output shaft 6 through the first driven gear 8 carried on the output shaft 6 and meshed with the first driving gear 7.

When the first clutch 13 is engaged and the second clutch 14 is disengaged, the power of the engine 1 can be transmitted to the first gear gearset via the first input shaft 4, thereby driving the output shaft 6 in rotation. Just so make this disclosure realize the design that integrates, engine 1 and driving motor 2 share first fender gear train and output shaft 6 promptly, can reduce the quantity of spare part, reduce the holistic volume of actuating system to rationally optimize the overall arrangement space, easily whole car carries on, also can reduce cost simultaneously, and engine 1 shares first fender gear train and can also realize the engine function of starting.

In practical applications, the hybrid drive system of the present disclosure may further include a power output portion 16, the power output portion 16 includes an output gear 161 and a differential 162, the differential 162 may be connected to wheels through a drive shaft, and the output gear 161 is connected to the output shaft 6 and the differential 162, respectively, so as to further transmit power transmitted to the output shaft 6 by the engine 1 and the drive motor 2 to the wheels.

The hybrid power driving system provided by the present disclosure can realize consideration of multiple driving modes, which will be described below with reference to the accompanying drawings.

FIG. 2 is a power transmission schematic diagram of a hybrid drive system in an electric-only drive mode provided according to one embodiment of the present disclosure. The engine 1 is not operated, the drive motor 2 is operated, and both the first clutch 13 and the second clutch 14 are disengaged. The power of the driving motor 2 is transmitted to the output shaft 6 through the first gear set, and then transmitted to the wheels through the power output part 16. The reverse rotation of the driving motor 2 can realize the function of reversing. In the driving mode, the wheels are directly driven by the driving motor 2, the transmission chain is shortest, the number of parts participating in power transmission is also smallest, and the transmission efficiency is improved.

3a-3c are power transfer schematic diagrams of a hybrid drive system in an engine direct drive mode provided in accordance with one embodiment of the present disclosure. The hybrid drive system of the present disclosure may be provided with a plurality of gear sets having different gear ratios, respectively, in order to enable multi-gear driving. The hybrid drive system of the present disclosure may further include a third gear gearset and a synchronizer 15 in addition to the first gear gearset and the second gear gearset described in the above-described embodiments. The third gear gearset has a different gear ratio than the first gear gearset and the second gear gearset, respectively. The third gear gearset, like the second gear gearset, comprises a third driving gear 11 carried by the second input shaft 5 and a third driven gear 12 carried by the output shaft 6.

The synchronizer 15 is axially slidably disposed on the second input shaft 5 between the second gear set and the third gear set, specifically, between the second driving gear 9 and the third driving gear 11. The synchronizer 15 selectively engages with the second gear gearset or the third gear gearset. The present disclosure is not limited to a specific structure of the synchronizer 15, and any synchronizer conventionally used in the art may be used. For example, the synchronizer 15 may be engaged with the second gear set or the third unit gear set through a sliding sleeve structure, specifically, a first bevel gear is disposed on an inner circumferential surface of the synchronizer 15, and a second bevel gear capable of being matched with the first bevel gear is axially and convexly disposed on portions of the second driving gear 9 and the third driving gear 11 facing the first bevel gear, so as to implement power transmission.

As an embodiment of the present disclosure, a gear ratio of the first gear set is greater than a gear ratio of the second gear set, and a gear ratio of the second gear set is greater than a gear ratio of the third gear set. It should be understood that the magnitude relationships of the different gear ratios between the multiple gear gears can be applied to the present disclosure and achieve the objective of shifting between the multiple gears. From the relationship between the gear ratio and the output torque, it is known that the larger the gear ratio, the larger the output torque. Therefore, for convenience of the following description, the gear corresponding to the first gear set is referred to as a low gear, the gear corresponding to the second gear set is referred to as a medium gear, and the gear corresponding to the third gear set is a high gear. In addition, according to the needs, the gear shifting device is not limited to three gears, and any number of gear shifting can be realized based on the same principle.

Fig. 3a shows a power transmission schematic diagram for the first gear direct drive of the engine. The engine 1 is operated, the drive motor 2 is not operated, the first clutch 13 is engaged, and the second clutch 14 is disengaged. The power of the engine 1 is transmitted to the output shaft 6 through the first gear gearset, and then transmitted to the wheels through the power output portion 16. Fig. 3b shows a power transmission schematic diagram of two-gear direct drive of the engine. The engine 1 works, the driving motor 2 does not work, the first clutch 13 is disconnected, the second clutch 14 is connected, the synchronizer 15 is connected to the second gear set, and the power of the engine 1 is transmitted to the output shaft 6 through the second gear set and then transmitted to wheels through the power output part 16. It is to be noted that in the mode including only the two-speed drive, the second clutch 14 is engaged to effect switching from the first-speed drive to the second-speed drive without the synchronizer 15 being involved, by disengaging the first clutch 13. Fig. 3b shows a power transmission schematic diagram of a three-gear direct drive of the engine. The engine 1 works, the driving motor 2 does not work, the first clutch 13 is disconnected, the second clutch 14 is connected, the synchronizer 15 is connected to the third gear set, and the power of the engine 1 is transmitted to the output shaft 6 through the third gear set and then transmitted to wheels through the power output part 16.

By controlling the connection or disconnection of the first clutch 13 and the second clutch 14, the two-gear or three-gear direct drive of the engine 1 is realized, and when a low vehicle speed is required, a gear with a large transmission ratio can be selected; when a higher vehicle speed is required, a gear with a lower transmission ratio can be selected, so that a high-efficiency area of the engine 1 is utilized to the maximum extent, a wider vehicle speed range can be obtained, the motor is miniaturized, and the system cost is saved.

The present disclosure achieves the purpose of separately transmitting power to the output shaft 6 by the first gear set and the second gear set, respectively, through the dual clutch module having the first clutch 13 and the second clutch 14. Like this, shift gears the in-process of switching, need not to mesh the gear that is not meshed and the rotational speed is different like correlation technique, because gear engagement process is not smooth and easy when having avoided shifting, lead to the condition of the process of shifting unsmooth to improve and drive experience. In addition, in the process of shifting gears, power can be compensated through the driving motor 2, so that the power is not interrupted in the process of shifting gears, and the smoothness of gear shifting is guaranteed. Alternatively, the hybrid drive system may further comprise a rotational speed sensing device (not shown) for monitoring the speed difference between the output shaft of the engine 1 and the first input shaft 4 and/or the speed difference between the output shaft of the engine 1 and the second input shaft 5, wherein the rotational speed sensor may be a resolver. Therefore, the rotating speeds of the shafts at the two ends of the clutch can be controlled by the controller connected with the rotary transformer according to the actually measured rotating speeds, and when the speed difference is reduced to be within the preset threshold range, the clutch is allowed to be combined, so that the smoothness of gear switching is further guaranteed.

Fig. 4 is a power transmission diagram of the hybrid drive system in the energy recovery mode, in which the engine 1 and the drive motor 2 are both operated, and the first clutch 13 and the second clutch 14 are both disengaged, according to an embodiment of the present disclosure. The kinetic energy of the wheels is transmitted to the output shaft 6 through the power output part 16 and then transmitted to the driving motor through the first gear, so that the driving motor 2 is generated, and the energy is recovered to a power battery of the driving motor 2.

According to an embodiment of the present disclosure, the hybrid drive system of the present disclosure may further include a generator 3, and the generator 3 is connected with the output shaft of the engine 1 through a generator output gear set 18, so that the engine 1 can drive the generator 3 to generate electricity. FIG. 5 is a power transfer schematic of a hybrid drive system in an idle charge mode provided in accordance with an embodiment of the present disclosure. The engine 1 is operated, the drive motor 2 is not operated, and both the first clutch 13 and the second clutch 14 are disengaged. The power of the engine 1 is transmitted to the generator 3 through the generator output gear set 18 to charge the power battery of the generator 3.

Like the drive motor 2, the generator 3 can also be used to drive the wheel in rotation. The generator 3 can drive wheels independently, or form a double-motor driving mode together with the driving motor 2, or form a three-power driving mode together with the generator 3, the engine 1 and the driving motor 2. Take a dual-motor driving mode as an example, in which the driving motor 2 is a main driving source and outputs full power, and the generator 3 is an auxiliary driving source and outputs limited power. The first clutch 13 is engaged and the second clutch 14 is disengaged. The power of the driving motor 2 is transmitted to the output shaft 6 through the first gear set, and then transmitted to the wheels through the power output part 16. The power of the generator 3 is also transmitted to the output shaft 6 via the first gear gearset and then to the wheels via the power take-off 16. When the first clutch 13 is disengaged and the second clutch 14 is engaged, the multi-stage drive mode in the generator assist drive can be realized. The driving mode can be used in occasions with larger loads such as acceleration, climbing, overtaking, high speed and the like, and can provide better economy and lower noise.

FIG. 6 is a power transfer schematic in a range extended mode of a hybrid drive system provided in accordance with an embodiment of the present disclosure. The engine 1 and the drive motor 2 are both operated, and the first clutch 13 and the second clutch 14 are both disengaged. The power of the engine 1 is transmitted to the generator 3 through the generator output gear set 18 to charge the power battery of the generator 3. The power of the driving motor 2 is transmitted to the output shaft 6 through the first gear set, and then transmitted to the wheels through the power output part 16. This driving mode can be used for downhill, braking or deceleration of the vehicle, enabling maximization of the regenerative energy.

Fig. 7a-7b are power transmission schematic diagrams of a hybrid drive system in a hybrid drive mode provided in accordance with an embodiment of the present disclosure. Fig. 7a shows a power transmission diagram for a first-gear hybrid drive. The engine 1 and the drive motor 2 are both operated, the first clutch 13 is engaged, and the second clutch 14 is disengaged. In this driving mode, the power of the engine 1 and the power of the driving motor 2 are coupled and superposed on the first input shaft 4, specifically, the power of the engine 1 is transmitted to the output shaft 6 through the first gear set and then transmitted to the wheels through the power output part 16, and the power of the driving motor 2 is transmitted to the output shaft 6 through the first gear set and then transmitted to the wheels through the power output part 16. Fig. 7b shows a power transmission diagram for the second-gear hybrid drive. The engine 1 and the drive motor 2 are both operated, the first clutch 13 is disengaged, and the second clutch 14 is engaged. In this driving mode, the power of the engine 1 and the power of the driving motor 2 are coupled and superposed on the output shaft 6, specifically, the power of the engine 1 is transmitted to the output shaft 6 through the second gear set and then transmitted to the wheels through the power output part 16, and the power of the driving motor 2 is transmitted to the output shaft 6 through the first gear set and then transmitted to the wheels through the power output part 16. Although fig. 7b illustrates the second-gear hybrid driving, it should be understood that the principle of the third-gear hybrid driving is the same, and the power of the engine 1 needs to be output through the third-gear at this time, and the detailed process is not described herein again. Multiple engines are driven simultaneously, and power performance can be exerted to the maximum extent.

In the present disclosure, a disconnection mechanism (not shown) may be provided between the driving motor 2 and the first gear train for engaging or disengaging power transmission between the driving motor 2 and the first gear train. For example, in the engine direct-drive mode, the power transmission between the driving motor 2 and the first gear set is cut off, so that the efficiency of the engine direct-drive can be improved, and the driving motor 2 is prevented from generating counter electromotive force at a high speed. The disconnect mechanism may be a clutch or other structure known to those skilled in the art that is capable of interrupting power transmission, and will not be described in detail herein. Further, as shown in fig. 1, a damper 17 may be provided on the output shaft of the engine 1 to prevent vibration generated when the engine 1 is operated from being transmitted to the transmission to affect operations of various components in the transmission. The damper 17 may employ any damping mechanism known to those skilled in the art of power transmission, and will not be described in detail herein.

A second object of the present disclosure is to provide a vehicle that is equipped with the hybrid drive system described above and has all the advantageous effects of the system.

The preferred embodiments of the present disclosure are described in detail with reference to the accompanying drawings, however, the present disclosure is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present disclosure within the technical idea of the present disclosure, and these simple modifications all belong to the protection scope of the present disclosure.

It should be noted that the various features described in the above embodiments may be combined in any suitable manner without departing from the scope of the invention. To avoid unnecessary repetition, the disclosure does not separately describe various possible combinations.

In addition, any combination of various embodiments of the present disclosure may be made, and the same should be considered as the disclosure of the present disclosure, as long as it does not depart from the spirit of the present disclosure.

Claims

1. A hybrid drive system, characterized in that the hybrid drive system comprises:

an engine (1);

a transmission, the transmission comprising:

a first input shaft (4), an output shaft of the engine (1) being coaxially connected with the first input shaft (4);

the second input shaft (5), the said second input shaft (5) and said first input shaft (4) are coaxial to empty;

the output shaft (6) is arranged in parallel with the first input shaft (4) and is used for transmitting power to wheels;

a first gear set comprising a first driving gear (7) carried by the first input shaft (4) and a first driven gear (8) carried by the output shaft (6);

a second gear set having a different transmission ratio than the first gear set, the second gear set comprising a second driving gear (9) carried by the second input shaft (5) and a second driven gear (10) carried by the output shaft (6);

a dual clutch module, the dual clutch module comprising:

a first clutch (13) provided between an output shaft of the engine (1) and the first input shaft (4) for engaging or disengaging power transmission between the engine (1) and the first gear gearset;

a second clutch (14) provided between the output shaft of the engine (1) and the second input shaft (5) for engaging or disengaging power transmission between the engine (1) and the second gear set;

a drive motor (2), the drive motor (2) being connected with the first input shaft (4) or the output shaft (6) to output power to the output shaft (6).

2. Hybrid drive system according to claim 1, characterized in that it further comprises a generator (3) connected to the output shaft of the engine (1) through a generator output gear set (18), so that the engine (1) can drive the generator (3) to generate electricity.

3. The hybrid drive system according to claim 1 or 2, wherein the transmission further comprises:

a third gear set having a different transmission ratio to the first and second gear sets, respectively, the third gear set comprising a third driving gear (11) carried by the second input shaft (5) and a third driven gear (12) carried by the output shaft (6);

a synchronizer (15) axially slidably disposed on the second input shaft (5) and located between the second and third gear sets to selectively engage with the second gear set or with the third gear set.

4. The hybrid drive system of claim 3, wherein a gear ratio of the first gear gearset is greater than a rotational ratio of the second gear gearset, and a gear ratio of the second gear gearset is greater than a gear ratio of the third gear gearset.

5. Hybrid drive system according to claim 1, characterized in that the drive motor (2) is coaxially connected with the first input shaft (4) and outputs power to the output shaft (6) through the first gear set.

6. Hybrid drive system according to claim 1, characterized in that it further comprises a power take-off (16), said power take-off (16) comprising an output gear (161) and a differential (162), said output gear (161) being connected with said output shaft (6) and said differential (162), respectively, said differential (162) being connected with the wheels.

7. Hybrid drive system according to claim 1, characterized in that a disconnecting mechanism is provided between the drive motor (2) and the first gear wheel set for engaging or disconnecting power transmission between the drive motor (2) and the first gear wheel set.

8. Hybrid drive system according to claim 1, characterized in that a damper (17) is arranged on the output shaft of the engine (1).

9. Hybrid drive system according to claim 1, characterized in that it further comprises rotational speed sensing means for monitoring the speed difference between the output shaft of the engine (1) and the first input shaft (4) and/or the speed difference between the output shaft of the engine (1) and the second input shaft (5).

10. A vehicle characterized by comprising the hybrid drive system of any one of claims 1 to 9.