Abstract:
A vehicle hybrid propulsion system includes an internal combustion engine, a transmission, a plate clutch, and at least one electric actuator coupled with the engine and with the transmission for being able to perform one of the operations consisting of generating propulsive forces, generating electric power and idling. A lever mechanism driven by an electric motor is used to control engaging and disengaging of the plate clutch such that connection between the transmission and the engine and/or the electric motor can be established or blocked. Thus, hybrid propulsion systems having different functions can be formed. Moreover, the hybrid propulsion systems are easy to implement by combining modular components.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates generally to hybrid propulsion systems, and more particularly, to a vehicle hybrid propulsion system. 
   2. Description of Related Art 
   Generally, a vehicle propulsion system comprises a startup and power generating device so as to start an engine, provide required power to electric loads during operation of the engine or charge battery of the vehicle. 
   Such a device is disclosed by Japanese patent publication No. 10-148142. A startup coil and a power generating coil are disposed on a stator of a motor. In the case of start, electric power is provided to the startup coil by a battery so as to use the motor as a startup device. The motor as a startup device is directly connected to a crankshaft and drives the crankshaft to rotate, thereby starting up the engine. On the other hand, the commutator and the electric brush mechanism of the motor are in contact with each other through an adjusting mechanism. After the engine is started up, the rotation speed of the engine begins to increase. The rotation of the engine further propels the rotor of the motor to rotate. When the rotation speed of the rotor reaches a predefined value, the centrifugal force of the rotor actuates the adjusting mechanism, thereby cutting off the contact between the commutator and the electric brush mechanism. Thereafter, the motor is used as a power generating device for providing electric-motive forces to electric loads of the vehicle and charging the battery. 
   With further development of the vehicle industry, there has been proposed an assist hybrid propulsion system that integrates an engine with an assist propulsion device for providing propulsive forces to a vehicle. As disclosed in Taiwan patent publication No. 390939, an engine startup and assist device is used to start up the engine and provide torque assist for the engine such as when the vehicle climbs or needs to deliver a large torque. 
   With upcoming energy crisis and environment protection concern, current widely used hybrid propulsion system introduces an automatic Stop-Go function such as disclosed by Taiwan patent No. 487779 and Japanese publication No. 58-142378. Through the automatic Stop-Go function, the engine can be stopped when the vehicle stops and the engine stays at an idle state. The engine can then be automatically ignited to start up when the vehicle starts to go, thereby saving energy and decreasing air pollution. In addition, a full-function hybrid propulsion system has been developed, which can separately utilize propulsive forces of the engine or the electric motor. Therefore, the electric motor not only can provide assist propulsive forces to the engine, it also can independently provide propulsive forces to the vehicle according to the need, and meanwhile automatically stop the engine. 
   Most of the hybrid propulsion systems use a torque converter or planetary gear for propulsive force connection, only a small number of hybrid propulsion systems use a plate clutch for propulsive force connection. Meanwhile, currently, only the assist hybrid propulsion system connects the electric motor to the crankshaft of the engine directly such that the electric motor and the engine can rotate coaxially and synchronously. For example, an assist hybrid propulsion system disclosed by U.S. Pat. No. 6,729, 423 B2 controls a plate clutch through oil pressure. That is, an oil hydraulic pump drives an oil hydraulic cylinder to operate the clutch plate. Compared with a system that controls the plate clutch through a lever mechanism, the assist hybrid propulsion system of the above-mentioned invention is costly, and is difficult to assemble and maintain. Further, its operation speed is slow. In addition, the design of the plate clutch is space-consuming and its assembling position is difficult to be changed. Therefore, it is difficult to realize modular manufacturing flexibility. 
   SUMMARY OF THE INVENTION 
   Accordingly, an objective of the present invention is to provide a vehicle hybrid propulsion system that can obtain different functions by changing arrangement of modular components constituting the vehicle hybrid propulsion system. 
   Another objective of the present invention is to provide a low cost vehicle hybrid propulsion system. 
   A further objective of the present invention is to provide a vehicle hybrid propulsion system that is easy to maintain. 
   Still another objective of the present invention is to provide a vehicle hybrid propulsion system that can increase operation speed of separation and connection between propulsive forces of engine and electric motor. 
   In order to attain the above and other objectives, a vehicle hybrid propulsion system of the present invention comprises: an internal combustion engine; a transmission; a plate clutch having a level mechanism driven by an electric actuator for separating the plate clutch from the engine or coupling the plate clutch with the engine; and at least one electric actuator coupled with the engine and with the transmission for being able to perform one of the operations consisting of generating propulsive forces, generating electric power and idling. The lever mechanism comprises a push rod driven by the electric actuator, a lever propelled by the push rod, and a thrust ring propelled by the lever and capable of exerting forces on the plate clutch. The vehicle hybrid propulsion system further comprises an electronic controller for making the electric actuator perform one of the operations consisting of generating propulsive forces, generating electricity and idling. The electronic controller further controls forward and reverse cycling of the electric actuator so as to move vehicle forward or backward. The transmission is one of a manual transmission and an automatic transmission. 
   In order to attain same objectives, another vehicle hybrid propulsion system disclosed by the present invention comprises: an internal combustion engine; a transmission; a first electric actuator coupled with the engine for providing propulsive forces or generating electric power; a second electric actuator coupled with the transmission for generating propulsive forces or generating electric power; and a plate clutch disposed between the first and second electric actuators having a lever mechanism driven by an electric actuator for separating the engine and the first electric actuator from the second electric actuator or coupling the engine and the first electric actuator with the second electric actuator. The vehicle hybrid propulsion system further comprises an electronic controller for making the first and second electric actuators perform one of the operations consisting of generating propulsive forces, generating electricity and idling. The electronic controller can further control forward and reverse cycling of the second electric actuator so as to move vehicle forward or backward. The transmission is one of a manual transmission and an automatic transmission. The lever mechanism comprises a push rod driven by an electric actuator, a lever propelled by the push rod via a fulcrum, and a thrust ring propelled by the lever and capable of exerting forces on the plate clutch. 
   According to the hybrid propulsion system of the present invention, an electric motor is used to drive the lever mechanism of the plate clutch. Thus, connection between the sources of propulsive forces and the transmission, or connection between different sources of propulsive forces such as between the engine and the electric motor can be separated or reunited automatically, thereby achieving different hybrid propulsion systems having different functions. Meanwhile, the hybrid propulsion systems can easily be constructed with modular components, and the plate clutch is an already known and low cost mechanism. Therefore, a low cost hybrid propulsion system with simple structures and multi functions can be achieved so as to save fuel, enhance output power and obtain optimal operation performance. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
       FIG. 1  is a diagram of a hybrid propulsion system according to a first embodiment of the present invention; 
       FIG. 2  is a diagram of a hybrid propulsion system according to a second embodiment of the present invention; 
       FIGS. 3A and 3B  are diagrams of a hybrid propulsion system according to a third embodiment of the present invention; 
       FIG. 4  is a diagram of a hybrid propulsion system according to a fourth embodiment of the present invention; 
       FIG. 5  is a construction diagram of a hybrid propulsion system according to the third embodiment of the present invention; 
       FIG. 6  is a construction diagram of a hybrid propulsion system according to the fourth embodiment of the present invention; 
       FIG. 7  is a top view of a vehicle having a hybrid propulsion system according to the third embodiment of the present invention; and 
       FIG. 8  is a top view of a vehicle having a hybrid propulsion system according to the fourth embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
   The following illustrative embodiments are provided to illustrate the disclosure of the present invention, these and other advantages and effects can be apparent to those skilled in the art after reading the disclosure of this specification. The present invention can also be performed or applied by other different embodiments. The details of the specification may be on the basis of different points and applications, and numerous modifications and variations can be devised without departing from the spirit of the present invention. 
     FIGS. 1 to 4  respectively show a first, second, third and fourth embodiment of the present invention. Therein, vehicle hybrid propulsion systems shown in  FIGS. 1 ,  2  and  4  are full functional, i.e., propulsive forces of an engine  11  and an electric motor  12  can be outputted separately or outputted after combination; and vehicle hybrid propulsion system shown in  FIGS. 3A and 3B  is an assist hybrid propulsion system, i.e., propulsive forces are mainly outputted by an engine  11  while assisted by the propulsive forces of an electric motor  16 , and propulsive forces of the electric motor  16  can not be outputted independently. 
   Referring to  FIG. 1 , a hybrid propulsion system  1 A shown according to a first embodiment of the present invention. The hybrid propulsion system  1 A comprises an engine  11 , which can be stopped, be idling or generate propulsive forces. Therein, propulsive forces generated by the engine  11  can be outputted through an output shaft  111  of the engine  11 . The output shaft  111  of the engine  11  functions as a rotation axis of a rotor  163  of an electric motor  16  such that the rotor  163  can rotates coaxially and synchronously with the output shaft  111  of the engine  11 . The electric motor  16  further comprises a stator  162  disposed around the rotor  163  and inside the casing  161  of the electric motor  16 . The stator  162  transmits electric power through a power line  164 . Controlled by an electronic controller, the electric motor  16  can function as an electric generator that receives mechanical rotation energy and converts it into electric energy, or function as a motor that converts electrical energy of a battery into rotation energy, or stay at an idle state. 
   One end of the casing  161  of the electric motor  16  is fixed to the engine  11 , and the other end of the casing  161  is connected to a housing  131  of a plate clutch assembly  13 . The end of the output shaft  111  of the engine  11  is connected to one side of a flywheel  112 . The other side of the flywheel  112  is connected to a plate clutch  132 . Both the flywheel  112  and the plate clutch  132  are accommodated inside the housing  131 . The plate clutch  132  is a good hybrid propulsion connecting component. By accurately controlling disengaging and engaging of the plate clutch  132  so as to prevent occurrence of impact torsion, the plate clutch  132  can be operated normally. A position sensor  114  is mounted to the housing  131  for sensing the outer circumference of the flywheel  112  such that a position sensing signal can be generated. The position sensing signal is used to provide a timing signal required for controlling the electric motor  16 . 
   The plate clutch  132  is connected to the front end of an input shaft  151  of a transmission  15 . In general, the plate clutch  132  is kept at an engaged state, that is, propulsive forces of the engine  11  and electric motor  16  can be transmitted to the input shaft  151  of the transmission  15  through the flywheel  112  and the plate clutch  132 . The propulsive forces are then shifted by the transmission  15  and outputted to loads through output shafts  152 ,  153  of the transmission  15 . 
   Another electric motor  12  is disposed between the plate clutch assembly  13  and the transmission  15 . The electric motor  12  comprises a casing  121 , a stator  122  inside the casing  121  and a rotor  123  enclosed by the stator  122 . Therein, the rotor  123  is disposed on the input shaft  151  of the transmission  15  and rotates coaxially and synchronously with the input shaft  151 . The power line  124  is used to transmit electric power for the electric motor  12 . Another position sensor  125  is used to sense the timing signal of the rotating axis so as to generate a position sensing signal for controlling the electric motor  12 . 
   Controlled by an electronic controller, the electric motor  12  can function as an electric generator that receives mechanical rotation energy and converts it into electric energy, or function as a motor that converts electrical energy of a battery into rotation energy, or stay at an idle state. Since the electric motor  12  can be braked quickly while generating electricity and quickly go into an idle state, and have a low inertia mass, even if the electric motor  12  is not connected to the clutch, the generated impact torsion is small. Therefore, the electric motor  12  can be directly connected to the transmission  15 , which is an advantage of the present invention. When the electric motor  12  performs as an electric motor, propulsive forces generated by the electric motor  12  are exerted on the input shaft  151  and combined with propulsive forces of the engine  11  and electric motor  16  so as to form hybrid propulsive forces. 
   Outside the plate clutch assembly  13  there is disposed a electric actuator  14 , which comprises a motor  140  and an actuating mechanism  141 . The electric actuator  14  is used to drive a push rod  142 . The push rod  142  further propels a lever  133 . By using a fulcrum  135  as a supporting point, the lever  133  further propels a thrust ring  134  that directly exerts forces on the plate clutch  132 . When the motor  140  exerts forces, the plate clutch  132  will be propelled by the thrust ring  134  and go into a disengaged state until the reactive force of the plate clutch  132  is balanced with the thrust force of the thrust ring  134 . At this point, the plate clutch assembly  13  is switched into a disengaged state, and propulsive forces of the engine  11  and the electric motor  16  will be prevented from being transmitted to the input shaft  151  through the flywheel  112  and the plate clutch  132 . Instead, only propulsive forces of the electric motor  12  can be transmitted to the input shaft  151  and further processed by the transmission  15 . On the other hand, when the motor  140  stops exerting forces, forces exerted on the lever  133  will be reduced. The restoring forces of the plate clutch  132  are bigger than the propulsion forces exerted on the thrust ring  134  by the lever  133 . Therefore, the plate clutch  132  gradually moves into an engaged state. 
   The electric actuator  14  is actuated by electric power transmitted through the power line  143 . The electric actuator  14  further comprises a position sensor  144  for measuring the moving position of the push rod  142 , thereby controlling the moving position of the thrust ring  134  and the plate clutch  132 . Thus, the electric actuator  14  can indirectly sense the state of the plate clutch  13 . As a result, through special time functions between forces and loosening speed of the electric actuator  14 , the plate clutch  132  can smoothly go to an engaged or disengaged state, thereby preventing impact torsion generated during combination of different propulsive forces. The functions of such a hybrid propulsion system  1 A are described as follows. 
   When the plate clutch assembly  13  is at a disengaged state, the electric motor  12  can be used to generate propulsive forces. The propulsive forces are then shifted by the transmission  15  and further transmitted to loads. At this point, only a single kind of propulsive forces is provided to the vehicle for use at low speed with low load, no matter the engine  11  is stopped, idling, or generating propulsive forces. 
   When the plate clutch assembly  13  is at a disengaged state, the electric motor  12  generates reverse propulsive forces. The reverse propulsive forces are then shifted by the transmission  15  and further transmitted to loads. At this point, only a single kind of propulsive forces is provided to the vehicle for backing the vehicle at low speed with low load, no matter the engine  11  is stopped, idling, or generating propulsive forces. Thus, the transmission  15  does not need a backing mechanism. 
   When the plate clutch assembly  13  is at a disengaged state and the engine  11  is stopped, the electric motor  16  generates propulsive forces, and the propulsive forces further start up the engine  11  and make the engine  11  idle or generate propulsive forces, no matter the electric motor  12  functions as an electric generator, an electric motor or stays at an idle state. 
   When the plate clutch assembly  13  is at a disengaged state, propulsive forces of the engine  11  propels the electric motor  16  to generate electric power so as to charge the battery, no matter the electric motor  12  functions as an electric generator, an electric motor or stays at an idle state. 
   When the plate clutch assembly  13  is at a disengaged state, the electric motor  12  functions as an electric generator, which converts inertia forces generated while decreasing the vehicle speed or residual propulsive forces while braking the vehicle into electric power so as to charge the battery, no matter the engine  11  is stopped, idling, or generating propulsive forces. 
   When the plate clutch assembly  13  is at an engaged state, propulsive forces of the engine  11  is outputted to the transmission  15 , shifted by the transmission  15  and then transmitted to loads as a single kind of propulsive forces to be used in the vehicle at different speed with different loads. At this point, the electric motors  12 ,  16  stay at an idle state. 
   When the plate clutch assembly  13  is at an engaged state, propulsive forces of the engine  11  are combined with propulsive forces generated by one or both of the electric motors  12 ,  16 . Then the combined propulsive forces are outputted to the transmission  15 , shifted by the transmission  15  and then transmitted to loads. At this point, the other electric motor that does not generate propulsive forces can stay at an idle state. 
   When the plate clutch assembly  13  is at an engaged state, propulsive forces of the engine  11  are outputted to the transmission  15 , shifted by the transmission  15  and then transmitted to loads. At this point, one of the electric motors  12 ,  16  functions as an electric generator for generating electric power so as to charge the battery. The electric motor that does not function as an electric generator can stay at an idle state. 
   When the plate clutch assembly  13  is at an engaged state, the engine  11  is at an idle state. At this point, one or both of the electric motors  12 ,  16  function as an electric generator for converting inertia forces generated while decreasing the vehicle speed or residual propulsive forces while braking the vehicle into electric power for charging the battery. The electric motor that does not function as an electric generator can stay at an idle state. 
   Through the above functions, the vehicle having the hybrid propulsion system  1 A can make its engine stopped when the vehicle stops or when the vehicle is idle. The vehicle can be started up at a low speed by the electric motor  12 . The vehicle moving at a high speed can be driven by the engine  11 . When the vehicle accelerates, the electric motor  12  or  16  can output propulsive forces for assisting the engine  11 . When the vehicle decelerates or brakes, the electric motor  12  or  16  functions as an electric generator so as to convert the propulsive forces into electric power. The above functions are helpful to save fuel. In addition, the electric motor  12  rotating in reverse can provide propulsive forces for backing the vehicle, thereby eliminating the need of a backing mechanism in the transmission  15  and accordingly reducing cost. In addition, the system not only can generate electric power while the vehicle moves, even if the vehicle stops, the electric motor  16  can convert propulsive forces from the engine  11  into electric power, thereby increasing functionality of the present hybrid propulsion system. 
     FIG. 2  shows a modular hybrid propulsion system  1 B according to a second embodiment of the present invention. The electric motor  16  in  FIG. 1  is used to assist the engine  11 . Thus, the electric motor  16  is disposed on the output shaft  111  of the engine  11 . Different from the electric motor  16  of  FIG. 1 , an electric motor  17  in  FIG. 2  is disposed on a back shaft  113  opposing to the output shaft  111  of the engine  11 . However, the electric motors  16 ,  17  have same function. 
   The electric motor  17  comprises a casing  171  fixed to one side of the engine  11  opposing to the output end thereof, a stator  172  fixed inside the casing  171 , and a rotor  173  enclosed by the stator  172 . The rotor  173  is disposed on the back shaft  113  of the engine  11  and rotates coaxially and synchronously with the back shaft  113 . The stator  172  is connected to the battery through the power line  174 . Controlled by an electronic controller, the electric motor  17  can function as an electric generator, function as an electric motor, or stay at an idle state. Therefore, the modular hybrid propulsion system  1 B have same hybrid propulsion functions as the modular hybrid propulsion system  1 A. However, since the electric motor  17  is disposed on the back end of the engine  11 , it can facilitate the assembly, maintenance and it is helpful to obtain a better heat dissipating effect. 
   If the electric motor  12  is eliminated from the hybrid propulsion system  1 A, an assist hybrid propulsion system  1 C is obtained, as shown in  FIG. 3A , the functions of which is described as follows. 
   When the plate clutch assembly  13  is at a disengaged state and the engine  11  is stopped, the electric motor  16  generates propulsive forces to start up the engine  11  and make the engine  11  idle or generate propulsive forces. 
   When the plate clutch  13  is at a disengaged state, propulsive forces of the engine  11  propels the electric motor  16  to generate electric power so as to charge the battery of the vehicle. 
   When the plate clutch assembly  13  is at an engaged state, propulsive forces of the engine  11  are outputted to the transmission  15 , shifted by the transmission  15  and then transmitted to loads. At this point, the electric motor  16  can be at an idle state. 
   When the plate clutch assembly  13  is at an engaged state, propulsive forces of the engine  11  are outputted to the transmission  15 , shifted by the transmission  15  and then transmitted to loads. At this point, the electric motor  16  functions as an electric generator for charging the battery of the vehicle. 
   When the plate clutch assembly  13  is at an engaged state, propulsive forces of the engine  11  and electric motor  16  are combined and outputted to the transmission  15 , shifted by the transmission  15  and then transmitted to loads. Such a function can be used at different speed and different loads, especially when the vehicle needs to be accelerated. 
   When the plate clutch assembly  13  is at an engaged state, the electric motor  16  functions as an electrical generator for converting inertia forces while decreasing the vehicle or residual propulsive forces while braking the vehicle into electric power so as to charge the battery. 
   Through the above functions, the vehicle having the present propulsion system can make its engine stopped when the vehicle stops or the vehicle is idle. By starting up the engine  11  through the electric motor  16 , the vehicle can be started up at a low speed. The vehicle moving at a high speed can be driven by the engine  11 . When the vehicle accelerates, the electric motor  16  can output propulsive forces for assisting the engine  11 . When the vehicle decelerates or brakes, the electric motor  16  can function as an electric generator so as to convert the propulsive forces into electric power. The above functions are helpful to save fuel. In addition, the system not only can generate electric power while the vehicle moves, even if the vehicle stops, the electric motor  16  can convert propulsive forces from the engine  11  into electric power, thereby increasing functionality of the present hybrid propulsion system. 
   As mentioned above, the electric motor  16  functions as an assist component for the engine  11 . The electric motor  16  can be disposed either on the output shaft  111  or the back shaft  113  of the engine without changing the function thereof. The hybrid propulsion system with the electric motor  16  disposed on the back shaft  113  of the engine  11  is shown in  FIG. 3B . The advantage of such is system is that the system is easy to assemble, maintain and has a better heat dissipation effect. 
   Further, if the electric motor  16  of the hybrid propulsion system  1 A is eliminated, another full-function hybrid propulsion system ID is obtained, as shown in  FIG. 4 , the functions of which are described as follows. 
   When the plate clutch  13  is at a disengaged state, propulsive forces generated by the electric motor  12  are outputted to the transmission  15 , shifted by the transmission  15  and then transmitted to loads, no matter the engine  11  is stopped, idling or generating propulsive forces. 
   When the plate clutch  13  is at a disengaged state, reverse propulsive forces generated by the electric motor  12  are outputted to the transmission  15 , shifted by the transmission  15  and then transmitted to loads. At this point, only a single kind of propulsive forces is provided to the vehicle for backing the vehicle at low speed with low load, no matter the engine  11  is stopped, idling, or generating propulsive forces. Thus, the transmission  15  does not need a backing mechanism. 
   When the plate clutch  13  is at a disengaged state, the electric motor  12  converts inertia forces while the vehicle decelerates and propulsive forces while the vehicle brakes into electric power so as to charge the battery, no matter the engine  11  is stopped, idling, or generating propulsive forces. 
   When the plate clutch  13  is at a disengaged state, the electric motor  12  generate propulsive forces to propel the vehicle to a certain speed. Then, the plate clutch  13  is changed to an engaged state, inertia forces of the vehicle propels the engine  11  to rotate such that the engine  11  can be started up. Thus, the start-up mechanism of the engine  11  such as start-up motors and start-up gears becomes unnecessary. 
   When the plate clutch  13  is at an engaged state, propulsive forces of the engine  11  is outputted to the transmission  15 , shifted by the transmission  15  and transmitted to loads. At this point, the electric motor  12  stays at an idle state. 
   When the plate clutch  13  is at an engaged state, propulsive forces of the engine  11  is combined with the propulsive forces of the electric motor  12 , outputted to the transmission  15 , shifted by the transmission  15  and transmitted to loads. 
   When the plate clutch  13  is at an engaged state, propulsive forces of the engine  11  is outputted to the transmission  15 , shifted by the transmission  15  and transmitted to the load. Meanwhile, the electric motor  12  functions as an electrical generator for charging the battery. 
   When the plate clutch  13  is at an engaged state, the engine  11  is at an idle state. The electric motor  12  converts inertia forces when the vehicle decelerates and residual propulsive forces when the vehicle brakes so as to generate electric power for charging the battery. 
     FIGS. 5 and 6  respectively show construction diagrams according to the third and fourth hybrid propulsion systems. Actually, the vehicle can be provided with other components and control systems so as to build a complete hybrid propulsion vehicle. 
     FIG. 7  shows a top view of a vehicle with a hybrid propulsion system according to the third embodiment of the present invention. The hybrid propulsion system  1 C comprises an engine  11 , an electric motor  12 , a plate clutch  13 , a electric actuator  14  and a transmission  15 . An electronic control system  2  is used to control the engine  11 , the electric motor  12  and the electric actuator  14  such that the hybrid propulsion system can have special functions at different circumstances, thereby saving fuel and obtaining optimal drive and control effect. 
   The present embodiment further comprises a primary battery  18  that can provide electric power to the electric motor  12  and can be charged by the electric motor  12 . A battery control unit  24  is provided to control current and voltage of the primary battery  18  so as to maintain the battery  18  at an optimal electric power range and safe state. Further, a DC/DC converting module  25  is used to convert a higher voltage of the primary battery  18  into a lower voltage needed by general vehicle circuit and controller. In addition, a motor control unit  23  is used to control operation state of the electric motor  12  such as the torque value and output current value of the electric motor. 
   An engine control unit  22  is used to receive an accelerating or decelerating signal transmitted by a throttle position sensor  26  so as to control state of the engine  11  and output torque rotation speed value. A vehicle control unit  21  can use the propulsion position sensing signal transmitted by the hybrid propulsion system and the vehicle speed sensing signal transmitted by the drive system for judging. The vehicle control unit  21  can be communicated with the battery control unit  24 , the motor control unit  23  and engine control unit  22  through network. For different hybrid propulsion systems of the present invention, parameters of the control software need to be slightly changed so as to obtain an optimal effect. 
     FIG. 8  is a top view of a vehicle having a hybrid propulsion system according to the fourth embodiment of the present invention. The hybrid propulsion system ID comprises an engine  11 , an electric motor  12 , a plate clutch module  13 , a electric actuator  14  and a transmission  15 . An electronic circuit control system  2  is used to control the engine  11 , the electric motor  12  and the electric actuator  14  such that the hybrid propulsion system can have special functions at different circumstances, thereby saving fuel and obtaining optimal drive and control effect. 
   The present embodiment further comprises a primary battery  18  that can provide electric power to the electric motor  12  and can be charged by the electric motor  12 . A battery control unit  24  can control current and voltage of the primary battery  18  so as to maintain the battery at an optimal electric power range and safe state. Further, a DC/DC converting module  25  is used to convert a higher voltage of the primary battery  18  into a lower voltage needed by general vehicle circuit and controller. 
   In addition, a motor control unit  23  is used to control operation state of the electric motor  12  such as the torque value and output current value of the electric motor. An engine control unit  22  is used to receive an accelerating or decelerating signal transmitted by a throttle position sensor  26  so as to control state of the engine  11  and output torque rotation speed value. A vehicle control unit  21  can use the propulsion position sensing signal transmitted by the hybrid propulsion system and the vehicle speed sensing signal transmitted by the drive system for judging. The vehicle control unit  21  can be communicated with the battery control unit  24 , the motor control unit  23  and engine control unit  22  through network. For different hybrid propulsion systems of present invention, parameters of the control software need to be slightly changed to obtain an optimal effect. 
   According to the hybrid propulsion system of the present invention, an electric motor is used to drive the lever mechanism of the plate clutch. Thus, connection between the sources of propulsive forces and the transmission, or connection between different sources of propulsive forces such as between the engine and the electric motor can be separated or reunited automatically, thereby achieving different hybrid propulsion systems having different functions. Meanwhile, the hybrid propulsion systems can easily be constructed with modular components, and the plate clutch is an already known and low cost mechanism. Therefore, a low cost hybrid propulsion system with simple structures and multi functions can be achieved so as to save fuel, enhance output power and obtain optimal operation performance. 
   The above-described descriptions of the detailed embodiments are only to illustrate the preferred implementation according to the present invention, and it is not to limit the scope of the present invention. Accordingly, all modifications and variations completed by those with ordinary skill in the art should fall within the scope of present invention defined by the appended claims.