DE69615745T2 - Drive arrangement and control of the overdrive for a hybrid vehicle - Google Patents

Description

Background of the invention

The present invention relates to an energy output device and a method for controlling the same. More specifically, the invention relates to an energy output device for transmitting and using energy generated by an internal combustion engine with high efficiency and for rotating a drive shaft at a speed higher than that of the output shaft of the internal combustion engine. The invention also relates to a method for controlling such an energy output device.

Description of the state of the art

Torque converters using a fluid are generally used to convert an output torque of an internal combustion engine or the like into energy and to transmit the converted energy. In conventional fluid-based torque converters, an input shaft and an output shaft are not fully engaged with each other; accordingly, an energy loss occurs corresponding to a slip that occurs between the input shaft and the output shaft. The energy loss consumed as heat is expressed as a product of the speed difference between the input shaft and the output shaft and the torque transmitted at that time. In vehicles on which such a torque converter is mounted, a large energy loss occurs in a transient state such as at a start-up time. The efficiency of energy transmission is not 100% even in stationary driving. Compared with manual transmissions, the torque converters result in lower fuel consumption.

Some proposed power output devices, unlike conventional torque converters, do not use fluid for torque conversion or power transmission, but transmit power by mechanical-electrical-mechanical conversion. For example, a power output device disclosed in Japanese Patent Laid-Open Gazette No. 53-133814 couples an output shaft of an internal combustion engine to a rotary shaft of a DC motor via an electromagnetic clutch to make the rotary shaft function as a drive shaft. The internal combustion engine drives a rotor on the DC field winding side of the electromagnetic clutch, while the other rotor on the AC armature winding side drives the rotary shaft of the DC motor or the drive shaft. Electric energy generated by slip between the two rotors of the electromagnetic clutch is supplied from the rotor on the AC armature winding side to the DC motor via a rectifier. The DC motor also receives electric energy from a battery to rotate the drive shaft. Unlike conventional fluid-based torque converters, this proposed structure has substantially no energy loss due to slip. Accordingly, it is possible to make the energy loss in the power transmission device relatively small by improving the efficiency of the electromagnetic clutch and the DC motor.

However, in the proposed power output device discussed above, the rotary shaft of the DC motor (ie, the drive shaft) is controlled to rotate at a speed lower than that of the output shaft of the internal combustion engine in the stationary state. However, at a time of starting the internal combustion engine, the speed of the drive shaft is temporarily increased. than that of the output shaft of the internal combustion engine. The proposed structure does not take into account the overdrive operation in which the input shaft is rotated at a speed higher than that of the output shaft of the internal combustion engine.

Document DE-A-30 25 756 discloses a structure that corresponds to the preamble of the independent claims.

Summary of the invention

The object of the present invention is therefore to provide an energy output device which transfers and uses energy from an internal combustion engine with a high degree of efficiency and enables a drive shaft to rotate at a speed higher than that of the output shaft of the internal combustion engine, and also to provide a method for controlling such an energy output device.

At least part of the above object is implemented by a first energy output device for outputting energy to a drive shaft.

The first energy output device comprises: an internal combustion engine with an output shaft, a first motor with a first rotor connected to the output shaft of the internal combustion engine and a second rotor connected to the drive shaft, wherein the second rotor is arranged coaxially and rotatably with respect to the first rotor and the first and second rotors are electromagnetically coupled to one another, whereby energy is transmitted between the output shaft of the internal combustion engine and the drive shaft via the electromagnetic coupling of the first and second rotors, a drive circuit for the first motor for exchanging electrical currents with the first motor in order to achieve the electromagnetic coupling of the first rotor with the second rotor, a second motor having a stator and a third rotor connected to either the drive shaft or the output shaft of the internal combustion engine, the stator being electromagnetically coupled to the third rotor, a drive circuit for the second motor for exchanging electrical currents with the second motor to change the electromagnetic coupling of the stator with the third rotor, and a control device for controlling the drive circuit for the first and second motors to adjust the speeds of the drive shaft and the output shaft of the internal combustion engine so that the speed of the drive shaft is higher than the speed of the output shaft.

In the first power output device, the rotational speed of the drive shaft is increased to be higher than the rotational speed of the output shaft of the internal combustion engine. Therefore, when the first power output device is mounted on a vehicle to drive its axles, the vehicle falls into overdrive. More specifically, even when the vehicle is driven at high speed, the first power output device enables the internal combustion engine to be driven at high efficiency without increasing the rotational speed of the output shaft of the engine, thereby improving fuel consumption.

According to one aspect of the invention, the control means comprises means for controlling the drive circuit for the second motor to enable the second motor to regenerate electrical energy and for controlling the drive means for the first motor to supply the regenerated electrical energy to the first motor for driving the first motor.

In this structure, the electrical energy regenerated by the second motor compensates that generated by the first engine consumes electrical energy. This increases the speed of the drive shaft so that it is higher than the speed of the output shaft of the combustion engine.

According to another aspect of the invention, the first power output device further comprises a storage device for storing electric energy. The control device comprises means for controlling the drive circuit for the second motor to allow the second motor to regenerate electric energy and for controlling the drive circuit for the first motor to supply the regenerated electric energy and the electric energy stored in the storage device to the first motor for driving the first motor.

This structure rotates the drive shaft not only with the electric energy regenerated by the second motor but also with the electric energy stored in the storage device, thereby outputting a sufficiently large torque to the drive shaft.

According to yet another aspect of the invention, the first energy output device further comprises a storage device for storing electrical energy. The control device comprises means for controlling the drive circuit for the second motor to enable the second motor to regenerate electrical energy, and for controlling the drive circuit for the first motor to supply the regenerated electrical energy to the first motor for driving the first motor and at least partially to the storage device for storing it.

This structure is particularly suitable for the case where the storage device has a small remaining capacity.

According to yet another aspect of the invention, the first energy output device further comprises a storage device for storing electrical energy. The control device comprises means for controlling the drive circuit for the first motor to supply the electrical energy from the storage device to the first motor for driving the first motor.

Therefore, in this structure, the electric energy is not supplied to the storage device because the second motor does not perform the regeneration of the electric energy. Instead, the electric energy stored in the storage device by the first motor is actively consumed. This operation can reduce the electric energy in the storage device to an appropriate level even when the storage device has been fully charged.

According to another aspect of the invention, the first power output device further comprises a storage device for storing electrical energy. The control device comprises means for controlling the drive circuit for the second motor to supply the electrical energy from the storage device to the second motor for driving the second motor, and for controlling the drive circuit for the first motor to supply the electrical energy from the storage device to the first motor for driving the first motor.

This structure allows both the first motor and the second motor to perform the power operation. The drive shaft accordingly receives not only the torque generated by the first motor but also the torque generated by the second motor acting in the direction of rotation of the drive shaft. More specifically, a large torque is applied to the drive shaft. This structure is particularly suitable for the case where where a high torque is required, for example when the vehicle approaches a slope or the driver wants to overtake another vehicle while driving at high speed on the motorway or main road.

According to yet another aspect of the invention, a second energy output device for outputting energy to a drive shaft comprises: an internal combustion engine having an output shaft, a motor having a first rotor connected to the output shaft of the internal combustion engine and a second rotor connected to the drive shaft, the second rotor being coaxially and rotatably arranged with respect to the first rotor and the first and second rotors being electromagnetically coupled to one another, whereby energy is transmitted between the output shaft of the internal combustion engine and the drive shaft via the electromagnetic coupling of the first and second rotors, a motor drive circuit for exchanging electrical currents with the first motor to change the electromagnetic coupling of the first rotor with the second rotor, a storage device for storing electrical energy, and a control device for controlling the motor drive circuit to supply the electrical energy from the storage device to the motor to drive the motor, whereby the drive shaft is rotated at a speed higher than a Speed of the output shaft of the combustion engine.

In the second power output device with only one motor, the motor is driven by the electric energy stored in the storage device to rotate the input shaft at a speed higher than that of the output shaft of the internal combustion engine. This structure also implements overdrive control.

According to a further aspect of the invention, a third energy delivery device for delivering mechanical Energy as energy to a drive shaft: an internal combustion engine connected to a rotary shaft, a first motor connected to the rotary shaft, and a second motor connected to the drive shaft, wherein the internal combustion engine generates mechanical energy and transmits the mechanical energy to the rotary shaft, wherein the first motor converts electrical energy supplied from the second motor into mechanical energy and transmits a sum of the converted mechanical energy and the mechanical energy transmitted via the rotary shaft to the second motor, wherein the second motor converts a portion of the mechanical energy transmitted from the first motor into electrical energy, supplies the electrical energy to the first motor, and outputs the remainder of the transmitted mechanical energy to the drive shaft, and wherein the first motor is driven to rotate the drive shaft at a speed higher than a speed of the rotary shaft.

The third energy output device of the invention can transmit or utilize the mechanical energy generated by the internal combustion engine through energy conversion with a high efficiency.

According to yet another aspect of the invention, a fourth energy output device for outputting mechanical energy as energy to a drive shaft comprises: an internal combustion engine connected to a rotary shaft, a first motor connected to the rotary shaft, a second motor connected to the drive shaft, and a storage device for storing electrical energy, wherein the internal combustion engine generates mechanical energy and transmits the mechanical energy to the rotary shaft, wherein the storage device stores electrical energy and supplies the stored electrical energy to the first motor, wherein the first motor uses the electrical energy supplied from the second motor and the storage device energy into mechanical energy and transmits a sum of the converted mechanical energy and the mechanical energy transmitted via the rotary shaft to the second motor, wherein the second motor converts a portion of the mechanical energy transmitted by the first motor into electrical energy, supplies the electrical energy to the first motor, and outputs the remainder of the transmitted mechanical energy to the drive shaft, and wherein the first motor is driven to rotate the drive shaft at a speed higher than a speed of the rotary shaft.

This structure is preferably used in the case that the second motor cannot supply sufficient electrical energy.

According to another aspect of the invention, a fifth energy output device for outputting mechanical energy as energy to a drive shaft comprises: an internal combustion engine connected to a rotary shaft, a motor connected to the rotary shaft and the drive shaft, and a storage device for storing electrical energy, wherein the internal combustion engine generates mechanical energy and transmits the mechanical energy to the rotary shaft, and the motor converts the electrical energy supplied from the storage device into mechanical energy and outputs a sum of the converted mechanical energy and the mechanical energy transmitted via the rotary shaft to the drive shaft, and the motor is driven to rotate the drive shaft at a speed higher than a speed of the rotary shaft.

In this structure, in addition to the mechanical energy generated by the internal combustion engine, the drive shaft can absorb the mechanical energy generated by converting the energy stored in the storage device. electrical energy was obtained. More precisely, a large amount of mechanical energy is applied to the drive shaft.

According to yet another aspect of the invention, a sixth energy output device for outputting mechanical energy as energy to a drive shaft comprises an internal combustion engine connected to a rotary shaft, a first motor connected to the rotary shaft, a second motor connected to the drive shaft, and a storage device for storing electrical energy, the internal combustion engine generating mechanical energy and transmitting the mechanical energy to the rotary shaft, the first motor converting the electrical energy supplied from the storage device into mechanical energy and transmitting a sum of the converted mechanical energy and the mechanical energy transmitted via the rotary shaft to the second motor, the second motor converting the electrical energy supplied from the storage device into mechanical energy and outputting a sum of the converted mechanical energy and the mechanical energy transmitted from the first motor to the drive shaft, and the first motor being driven to rotate the drive shaft at a speed higher than a speed of the rotary shaft.

The drive shaft therefore absorbs a great deal of mechanical energy.

According to a further aspect of the invention, a seventh energy output device for outputting mechanical energy as energy to a drive shaft comprises: an internal combustion engine connected to a rotary shaft, a first motor connected to the drive shaft, a second motor connected to the rotary shaft, and a storage device for storing electrical energy, wherein the internal combustion engine generates mechanical energy and transmits the mechanical energy to the rotary shaft, wherein the second motor converts a portion of the mechanical energy transmitted via the rotary shaft into electrical energy, supplies the electrical energy to the first motor, and transmits the remainder of the transmitted mechanical energy to the first motor, wherein the first motor converts the electrical energy supplied by the second motor into mechanical energy and outputs a sum of the converted mechanical energy and the mechanical energy transmitted by the second motor to the drive shaft, and the second motor is driven to drive the drive shaft at a speed higher than the speed of the rotary shaft.

The seventh energy output device of the invention has the same effects as the third energy output device discussed above.

The above object is also achieved by a method for controlling an energy delivery device for delivering energy to a drive shaft.

The method comprises the steps of: (a) providing an internal combustion engine with an output shaft, a first motor with a first rotor connected to the output shaft of the internal combustion engine and a second rotor connected to the drive shaft, the second rotor being arranged coaxially and rotatably with respect to the first rotor and the first and second rotors being electromagnetically coupled to one another, whereby energy is transmitted between the output shaft of the internal combustion engine and the drive shaft via the electromagnetic coupling of the first and second rotors, and a second motor with a stator and a third rotor connected to the drive shaft, the stator being electromagnetically coupled to the third rotor and (b) adjusting the speeds of the input shaft and the output shaft of the internal combustion engine so that the speed of the input shaft is higher than the speed of the output shaft.

Even if the speed of the drive shaft is high, the method enables the internal combustion engine to be driven with a high efficiency without increasing the speed of the output shaft of the internal combustion engine.

These and other objects, features, aspects and advantages of the present invention will become apparent from the following detailed description of the preferred embodiments with the accompanying drawings.

Short description of the drawings

Fig. 1 schematically illustrates a structure of an energy output device 20 as a first embodiment according to the present invention,

Fig. 2 is a cross-sectional view showing detailed structures of a clutch motor 30 and an auxiliary motor included in the power output device 20 of Fig. 1,

Fig. 3 is a schematic view showing a general structure of a vehicle in which the energy output device 20 of Fig. 1 is installed,

Fig. 4 is a graph schematically showing an amount of energy regenerated by the clutch motor 30 and the energy consumed by the assist motor 40,

Figure is a graphical representation showing an amount of energy consumed by the clutch motor 30 and schematically represents an amount of energy regenerated by the auxiliary motor 40 in the overdrive state,

Fig. 6 is a flow chart showing a control process executed by the control CPU 90 in the high-speed state,

Fig. 7 is a flowchart showing details of the control process of the clutch motor 30 executed in step S100 in the flowchart of Fig. 6,

Fig. 8 is a flowchart showing details of the control process of the assist motor 40 executed in step S102 in the flowchart of Fig. 6,

Fig. 9(a) to 9(c) show an energy flow between the gasoline engine 50, the clutch motor 30, the auxiliary motor 40 and the battery 94,

Fig. 10 is a flow chart showing a control process in the overdrive state executed by the control CPU 90 in a second embodiment of the present invention,

Fig. 11 is a characteristic diagram showing the torque Tc of the clutch motor 30 versus the speed difference (Ne- Nd) for different values of the speed Nd,

Fig. 12 is a flow chart showing a control process in the overdrive state executed by the control CPU 90 in a third embodiment of the present invention,

Fig. 13 is a characteristic diagram illustrating an efficiency diagram of the motor,

Fig. 14 is a graph schematically showing an amount of energy consumed by the clutch motor 30 and an amount of energy consumed by the assist motor 40 according to the control process of Fig. 12,

Fig. 15 shows an energy flow between the petrol engine 50, the clutch motor 30, the auxiliary motor 40 and the battery 94,

Fig. 16 is a schematic view showing an essential part of another energy output device 20A as a modification of the invention,

Fig. 17 is a schematic view showing an essential part of still another energy output device 20B as a further modification of the invention,

Fig. 18 is a graph schematically showing an amount of energy regenerated by the clutch motor 30B and an amount of energy consumed by the auxiliary motor 40B in the modified structure of Fig. 17,

Fig. 19 shows an energy flow between the petrol engine 50, the clutch motor 30 and the auxiliary motor 40,

Fig. 20 is a schematic view showing an essential part of another energy output device 20C as still another modification of the invention,

Fig. 21 is a schematic view showing an essential part of still another energy output device 20D as a further modification of the invention, and

Fig. 22 shows an energy flow between the gasoline engine 50, the clutch motor 30 and the battery 94.

Description of the preferred embodiments

Fig. 1 is a schematic view showing the structure of a power output device 20 as a first embodiment according to the present invention, Fig. 2 is a cross-sectional view showing detailed structures of a clutch motor 30 and an auxiliary motor 40 included in the power output device 20 of Fig. 1, and Fig. 3 is a schematic view showing a general structure of a vehicle in which the power output device 20 of Fig. 1 is included. The general structure of the vehicle will be described first for convenience.

Referring to Fig. 3, the vehicle has a gasoline engine 50 driven by gasoline as a power source or prime mover. Air taken in from an air supply system via a throttle valve 66 is mixed with fuel, i.e., gasoline, injected from a fuel injection valve 51 in this embodiment. The air/fuel mixture is supplied to a combustion chamber 52 and explosively ignited and burned. The linear motion of a piston 54, which is depressed by the explosion of the air/fuel mixture, is converted into a rotational motion of the crankshaft 56. The throttle valve 66 is driven by a motor 68 to open and close. A spark plug 62 converts a high voltage applied by an ignition device 58 via a distributor 60 into a spark which explosively ignites and burns the air/fuel mixture.

The operation of the petrol engine 50 is controlled by an electronic control unit 70 (hereinafter referred to as EFIECU). The EFIECU 70 receives information from numerous sensors that detect the operating conditions of the gasoline engine 50. These sensors include a throttle position sensor 67 for detecting the valve travel or position of the throttle valve 66, a manifold vacuum sensor 72 for measuring a load applied to the gasoline engine 50, a water temperature sensor 74 for measuring the temperature of the cooling water in the gasoline engine 50, and a speed sensor 76 and an angle sensor 78 attached to the manifold 60 for measuring the speed and angle of rotation of the crankshaft 56. A starter switch 79 for detecting a start state ST of an ignition key (not shown) is also connected to the EFIECU 70. Other sensors and switches that connect to the EFIECU 70 are omitted from the drawings.

The crankshaft 56 of the gasoline engine 50 is connected to a drive shaft 22 via a clutch motor 30 and an auxiliary motor 40. The drive shaft 22 also connects to a differential gear 24, which then transmits the torque output from the drive shaft 22 to left and right drive wheels 26 and 28. The clutch motor 30 and the auxiliary motor 40 are driven and controlled by a controller 80. The controller 80 has an internal control CPU and receives inputs from a gear shift position sensor 84 attached to a gear shift 82 and an accelerator pedal position sensor 65 attached to an accelerator pedal 64, as will be described in detail later. The controller 880 sends a variety of data and information to the EFIECU 70 and receives a variety of them from the EFIECU 70 through communication. Details of the control procedure including a communication protocol will be described later.

Referring to Fig. 1, the power output device 20 essentially comprises the gasoline engine 50 for generating power, the clutch motor 30 having an outer rotor 32 and an inner rotor 34, the auxiliary motor 40 having a rotor 42, and the control device 80 for driving and controlling the clutch motor 30 and the auxiliary motor 40. The outer rotor 32 of the clutch motor 30 is mechanically connected to an end portion of the crankshaft 56 of the gasoline engine 50, while the inner rotor 34 thereof is mechanically connected to the rotor 42 of the auxiliary motor 40.

As shown in Fig. 1, the clutch motor 30 is constructed as a synchronous motor in which permanent magnets 35 are fixed to an inner surface of the outer rotor 32 and three-phase coils 36 are wound on slots formed in the inner rotor 34. Power is supplied to the three-phase coils 36 via a rotary converter 38. A thin laminated sheet of non-directional electromagnetic steel is used to form the teeth and slots for the three-phase coils 36 in the inner rotor 34. A resolver 39 for measuring a rotation angle θe of the crankshaft 56 is fixed to the crankshaft 56. The resolver 39 can also serve as the angle sensor 78 fixed to the distributor 60.

The auxiliary motor 40 is also constructed as a synchronous motor with three-phase coils 44 wound on a stator 43 fixed to a housing 45 to generate a rotating magnetic field. The stator 43 is also made of a thin laminated sheet of non-directional electromagnetic steel. A plurality of permanent magnets 46 are fixed to an outer surface of the rotor 42. In the auxiliary motor 40, an interaction between a magnetic field formed by the permanent magnets 46 and a rotating magnetic field formed by the three-phase coils 44 results in rotation of the Rotor 42. The rotor 42 is mechanically connected to the drive shaft 22 which functions as the torque output shaft of the energy output device 20. A resolver 48 for measuring a rotation angle Ad of the drive shaft 22 is attached to the drive shaft 22 which is further supported by a bearing 49 held in the housing 45.

The inner rotor 34 of the clutch motor 30 is mechanically connected to the rotor 42 of the auxiliary motor 40 and further to the drive shaft 22. When the rotation and axial torque of the crankshaft 56 of the gasoline engine 50 are transmitted to the inner rotor 34 of the clutch motor 30 via the outer rotor 32, the rotation and torque by the auxiliary motor 40 are added to or subtracted from the transmitted rotation and torque.

While the auxiliary motor 40 is constructed as a conventional permanent magnet three-phase synchronous motor, the clutch motor 30 has two rotating elements or rotors, i.e., the outer rotor 32 with permanent magnets and the inner rotor 34 with three-phase coils 36. The detailed structure of the clutch motor 30 is described with the cross-sectional view of Fig. 2. The outer rotor 32 of the clutch motor 30 is fixed to a peripheral end of a gear 57 provided around the crankshaft 56 by means of a push pin 59a and a screw 59b. A central portion of the gear 57 protrudes to form a shaft-like member to which the inner rotor 34 is rotatably fixed by means of bearings 37A and 37B. An end portion of the drive shaft 22 is fixed to the inner rotor 34.

A plurality of permanent magnets 35, four in this embodiment, are attached to the inner surface of the outer rotor 32 as described above. The permanent magnets 35 are magnetized toward the axial center of the clutch motor 30 and have magnetic poles with alternating reverse directions. The three-phase coils 36 of the inner rotor 34, which face the permanent magnets 35 across a small gap, are wound on a total of 24 slots (not shown) formed in the inner rotor 34. The supply of electricity to the respective coils forms magnetic fluxes which pass through the teeth (not shown) separating the slots. The supply of a three-phase alternating current to the respective coils causes this magnetic field to rotate. The three-phase coils 36 are connected to receive the electrical energy supplied from the rotary converter 38. The rotary converter 38 has primary windings 38a fixed to the housing 45 and secondary windings 38b fixed to the drive shaft 22 coupled to the inner rotor 34. Electromagnetic induction allows electrical energy to be transferred from the primary windings 38a to the secondary windings 39b or vice versa. The rotary converter 38 has windings for the three phases, ie for the U, V and W phases, to enable the transmission of three-phase electrical currents.

The interaction between a magnetic field formed by an adjacent pair of permanent magnets 35 and a rotating magnetic field formed by the three-phase coils 36 of the inner rotor 34 results in a variety of behaviors of the outer rotor 32 and the inner rotor 34. The frequency of the three-phase alternating current supplied to the three-phase coils 36 is generally equal to a difference between the rotational speed (revolutions per second) of the outer rotor 32, which is directly connected to the crankshaft 56, and the rotational speed of the inner rotor 34. This results in a slip between the rotations of the outer rotor 32 and the inner rotor 34. Details of the control procedures of the clutch motor 30 and the auxiliary motor 40 will be described later based on the flowcharts.

As described above, the clutch motor 30 and the auxiliary motor 40 are driven and controlled by the controller 80. Referring again to Fig. 1, the controller 80 includes a first drive circuit 91 for driving the clutch motor 30, a second drive circuit 92 for driving the auxiliary motor 40, a control CPU 90 for controlling both the first and second drive circuits 91 and 92, and a battery 94 having a number of secondary cells. The control CPU 90 is a single-chip microprocessor having a RAM 90a used as a working memory, a ROM 90b in which various control programs are stored, an input/output port (not shown), and a serial communication port (not shown) through which data is sent to and received from the EFIECU 70. The control CPU 90 receives a variety of data through the input/output port. The input data includes: a rotation angle θe of the crankshaft 56 of the gasoline engine 50 from the resolver 39, a rotation angle θd of the drive shaft 22 from the resolver 48, an accelerator pedal position AP (operating amount of the accelerator pedal 64) from the accelerator pedal position sensor 65, a gear shift position SP from the gear shift position sensor 84, clutch motor currents Iuc and Ivc from two ammeters 95 and 96 in the first drive circuit 91, auxiliary motor currents Iua and Iva from two ammeters 97 and 98 in the second drive circuit 92, and a remaining capacity BRM of the battery 94 from a remaining capacity measuring device 99. The remaining capacity measuring device 99 can determine the remaining capacity BRM of the battery by any known method, e.g. by measuring the relative density of an electrolyte solution in the battery 94 or the total weight of the battery 94, by calculating the currents and time for charging and discharging, or by causing an instantaneous short circuit between the terminals of the battery 94 and measuring an internal resistance across the electric current.

The control CPU 90 outputs a first control signal SW1 for driving six transistors Tr1 to Tr6 operating as switching elements of the first drive circuit 91, and a second control signal SW2 for driving six transistors Tr11 to Tr16 operating as switching elements of the second drive circuit 92. The six transistors Tr1 to Tr6 in the first drive circuit 91 constitute a transistor inverter and are arranged in pairs to operate as a source and a sink with respect to a pair of power lines P1 and P2. The three-phase coils (U, V, W) 36 of the clutch motor 30 are connected to the respective contacts of the paired transistors via the rotary converter 38. The power lines P1 and P2 are connected to plus and minus terminals of the battery 94, respectively. The first control signal Swl output from the control CPU 90 sequentially controls the power-on time of the paired transistors Tr1 to Tr6. The electric current flowing through each coil 36 is subjected to PWM (Pulse Width Modulation) to generate a quadrature sinusoidal wave, which allows the three-phase coils 36 to form a rotating magnetic field.

The six transistors Tr11 to Tr16 in the second drive circuit 92 also constitute a transistor inverter and are arranged in the same manner as the transistors Tr1 to Tr6 in the first drive circuit 91. The three-phase coils (U, V, W) 44 of the auxiliary motor 40 are connected to the respective contacts of the paired transistors. The second control signal SW2 output from the control CPU 90 sequentially controls the power-on time of the paired transistors Tr11 to Tr16. The electric current flowing through each coil 44 is subjected to PWM to obtain a quasi-sinusoidal wave, which allows the three-phase coils 44 to form a rotating magnetic field.

The following describes the essential operation of the power output device 20 constructed in this manner. First, the operation when the vehicle is driven in the normal state, that is, when the drive shaft 22 rotates at a lower speed than the crankshaft 56 of the gasoline engine 50, will be described. For example, it is assumed that the gasoline engine 50 driven by the EFIECU 70 rotates at a predetermined speed Ne. The drive shaft 22 rotates at a speed Nd that is lower than the predetermined engine speed Ne (Nd< Ne). When the control CPU 90 of the controller 80 outputs the first control signal SW1 for on-off control of the transistors Tr1 to Tr6 in the first drive circuit 91, a constant electric current flows through the three-phase coils 36 of the clutch motor 30 based on the difference between a rotational speed Ne of the crankshaft 56 of the gasoline engine 50 and the rotational speed Nd of the drive shaft 22 (i.e., a difference Nc (=Ne-Nd) between the rotational speed of the outer rotor 32 and that of the inner rotor 34 of the clutch motor 30). Accordingly, a certain slip exists between the outer rotor 32 and the inner rotor 34 of the clutch motor 30. That is, the inner rotor 34 rotates in the rotation direction of the crankshaft 56 at a speed lower than that of the crankshaft 56 of the gasoline engine 50. In this state, the clutch motor 30 functions as a generator and performs the regenerative operation to regenerate an electric power via the first drive circuit 91. In order to allow the auxiliary motor to consume energy identical to the electric power regenerated by the clutch motor 30, the control CPU 90 controls the transistors Tr11 to Tr16 in the second drive circuit 92 on and off. The on-off control of the transistors Tr11 to Tr16 allows an electric current to flow through the three-phase coils 44 of the auxiliary motor 40 and thus the auxiliary motor 40 performs the power operation to generate torque.

Fig. 4 is a graph schematically showing an amount of energy regenerated by the clutch motor 30 and an amount of energy consumed by the auxiliary motor 40. While the crankshaft 56 of the gasoline engine 50 is driven at a speed Ne and a torque Te, energy in a range Gc is regenerated as electric energy by the clutch motor 30. The regenerated energy is supplied to the auxiliary motor 40 and converted into energy in a range Ga that allows the drive shaft 22 to rotate at a speed Nd and a torque Td. The torque conversion is carried out in the manner discussed above; the energy corresponding to the slip in the clutch motor 30 or the speed difference (Ne-Nd) is thus given as a torque to the drive shaft 22.

The following describes the operation when the vehicle is driven at high speed on a highway or a main road, that is, when the drive shaft 22 rotates at a speed higher than that of the crankshaft 56 of the gasoline engine 50 (in the overdrive state). The gasoline engine 50 is generally controlled so that it is driven at the highest possible efficiency. The speed Ne of the crankshaft 56 of the gasoline engine 50 is accordingly limited to a high efficiency speed range. While the increased speed Nd of the drive shaft 22 may exceed a maximum value Nemax in the high efficiency speed range of the gasoline engine 50, the speed Ne of the crankshaft 56 cannot exceed the maximum value Nemax of the high efficiency speed range. Therefore, when the speed Nd of the drive shaft 22 exceeds the maximum value Nemax of the high efficiency speed range, the speed Nd of the drive shaft 22 becomes higher than the rotational speed Ne of the crankshaft 56. More precisely, the vehicle is driven in the overdrive state.

When the control CPU 90 of the controller 80 outputs the first control signal SW1 to turn on and off the transistors Trl to Tr6 in the first drive circuit 91 in the overdrive state, the clutch motor 30 functions as a normal motor and performs the power operation to improve the rotation speed of the inner rotor 34 with respect to the outer rotor 32. This allows the drive shaft 22 to continue to rotate at the higher speed Nd relative to the speed Ne of the gasoline engine. During its function as a normal motor, the clutch motor 30 consumes the electric power.

In order to enable the auxiliary motor 40 to regenerate energy identical to the electric energy consumed by the clutch motor 30, the control CPU 90 controls the transistors Tr11 to Tr16 in the second drive circuit 92 on and off. The on-off control of the transistors Tr11 to Tr16 enables the auxiliary motor 40 to perform the regenerative operation. Thus, an electric current flows through the three-phase coils 44 of the auxiliary motor 40; electric energy is thus regenerated via the second drive circuit 92. The regenerated energy is supplied to the clutch motor 30 as electric energy that compensates for the electric energy consumed by the clutch motor 30.

Fig. 5 is a graph schematically showing an amount of energy consumed by the clutch motor 30 and an amount of energy regenerated by the assist motor 40 in the overdrive state. For example, it is assumed that the crankshaft 56 of the gasoline engine 50 is driven at a speed Ne and a torque Te and that the drive shaft 22 rotates at a speed Nd and a torque Td. In this In this state, energy in a region Ga is regenerated as electric energy by the auxiliary motor 40. The regenerated energy is supplied to the clutch motor 30 and converted into energy in a region Gc, which is subsequently consumed by the clutch motor 30. As the torque Td of the drive shaft 22 (i.e., the output torque) decreases relative to the torque Te of the gasoline engine 50, the rotational speed Nd of the drive shaft 22 increases relative to the rotational speed Ne of the gasoline engine (i.e., the rotational speed of the crankshaft 56). In the graph of Fig. 5, Ta represents the torque of the auxiliary motor 40, and Tc and Nc denote the torque and rotational speed of the clutch motor 30.

Unlike the torque conversion and speed conversion discussed above, the power output device 20 of the embodiment can charge the battery 94 with a surplus of electric energy or discharge the battery 94 to supplement the electric energy. This is implemented by controlling the mechanical energy output from the gasoline engine 50 (i.e., the product of torque Te and speed Ne), the electric energy regenerated or consumed by the clutch motor 30, and the electric energy regenerated or consumed by the auxiliary motor 40. The output energy from the gasoline engine 50 can thus be transmitted as power to the drive shaft 22 with a higher efficiency.

Next, the control procedure of the controller 80 when the drive shaft 22 is rotated at a speed higher than that of the crankshaft 56 of the gasoline engine 50 (i.e., in the overdrive state) will be described. Figure 1 is a flowchart showing a control process in the overdrive state executed by the control CPU 90. When the program enters the routine, the control CPU 90 first takes in data of the speed Nd of the drive shaft 22. The rotational speed Nd of the drive shaft 22 can be calculated from the rotation angle θd of the drive shaft 22 read by the resolver 48.

The input speed Nd of the drive shaft 22 is compared with a reference speed NOD for the overdrive operation in step S82. If the input speed Nd exceeds the reference speed NOD, the program goes to the following step S84. Otherwise, the program exits the routine of Fig. 6. The reference speed NOD for the overdrive operation is set equal to, for example, the maximum value Nemax in the high efficiency speed range of the gasoline engine 50.

In step S84, the control CPU 90 reads the accelerator pedal position AP from the accelerator pedal position sensor 65. The driver steps on the accelerator pedal 64 when he senses insufficient output torque. The value of the accelerator pedal position AP accordingly represents the desired output torque (i.e., the torque of the drive shaft 22) that the driver requests. In the subsequent step S86, the control CPU 90 calculates a target output torque (torque of the drive shaft 22) Td* that corresponds to the input accelerator pedal position AP. The target output torque Td* is also referred to as an output torque set value. The output torque set values Td* were previously set for the respective accelerator pedal positions AP. In response to an input of the accelerator pedal position AP, the output torque control value Td* corresponding to the input accelerator pedal position AP is extracted from the preset output torque control values Td*.

In step S88, an amount of energy Pd to be output from the drive shaft 22 is calculated according to the expression Pd = Td*xNd, that is, by multiplying the extracted output torque control value Td* (of the drive shaft 22) by the input speed Nd of the drive shaft 22. The program then goes to step S90, in which the control CPU 90 sets a target engine torque Te* and a target engine speed Ne* of the gasoline engine 50 based on the output energy Pd thus obtained. Here, it is assumed that all of the energy Pd to be output from the drive shaft 22 is supplied by the gasoline engine 50. Since the mechanical energy supplied from the gasoline engine 50 is equal to the product of the torque Te and the speed Ne of the engine 50, the relationship between the output energy Pd and the target engine torque Te* and the target engine speed Ne* can be expressed as Pd = Te*xNe*. However, there are numerous combinations of the target engine torque Te* and the target engine speed Ne* that satisfy the above relationship. In this embodiment, an optimal combination of the target engine torque Te* and the target engine speed Ne* is selected to realize operation of the gasoline engine 50 with the highest possible efficiency. The target engine speed (rotational speed of the crankshaft 56) Ne* is accordingly set within the high efficiency speed range of the gasoline engine 50.

This means that the target engine speed (speed of the crankshaft 56) Ne* cannot exceed the maximum value Nemax in the high efficiency speed range of the gasoline engine 50. The reference speed NOD for the overdrive operation is set equal to the maximum value Nemax of the high efficiency speed range as described above. When the speed Nd of the drive shaft 22 exceeds the reference speed NOD, the speed Nd of the drive shaft 22 is always higher than the engine speed (speed of the crankshaft 56 of the gasoline engine 50) Ne. More specifically, the vehicle is in the overdrive state.

In the subsequent step S92, the control CPU 90 determines a torque set value Tc* of the clutch motor 30 based on the target engine torque Te* set in step S90. In order to keep the rotation speed Ne of the gasoline engine 50 at a substantially constant level, the torque of the clutch motor 30 is required to balance the torque of the gasoline engine 50. The processing in step S92 accordingly sets the torque set value Tc* of the clutch motor 30 equal to the target engine torque Te*.

The control CPU 90 calculates the electric power Pc consumed by the clutch motor 30 in step S94. The electric power Pc consumed by the clutch motor 30 is calculated from the torque command value Tc* of the clutch motor 30 set in step S92 and expressed as:

Pc = (1/ksc) · Tc* · Nc

where ksc represents an efficiency of power operation by the clutch motor 30 and Nc represents a rotational speed of the clutch motor 30. The rotational speed Nc of the clutch motor 30 is equal to the difference between the rotational speed of the drive shaft 22 and that of the crankshaft 56 and can thus be expressed as:

Nc = Nd - Ne*

where Nd is the rotational speed of the drive shaft 22 read in step S80 and Ne* is the target engine rotational speed set in step S90.

Assuming that the entire energy Pc consumed by the clutch motor 30 is covered by the regenerative energy of the auxiliary motor 40, in step S96, the energy regenerated by the auxiliary motor 40 is electrical energy Pa is set equal to the energy Pc consumed by the clutch motor.

In the subsequent step S98, a torque control value Ta* of the auxiliary motor 40 is calculated from the rotational speed Nd of the drive shaft 22 read in step S80 and the regenerative energy Pa of the auxiliary motor 40 set in step S96. The torque control value Ta* is expressed as:

Ta* = Pa/(KsaxNd)

where Ksa denotes a regeneration efficiency by the auxiliary motor 40.

After determining the torque control value Ta* of the assist motor 40, the program goes to steps S100, S102 and S104 to control the clutch motor 30, the assist motor 40 and the gasoline engine 50, respectively. For the sake of explanation convenience, the control operations of the clutch motor 30, the assist motor 40 and the gasoline engine 50 are shown as separate steps. However, in the actual procedure, these control operations are carried out in complex. For example, the control CPU 90 simultaneously controls the clutch motor 30 and the assist motor 40 by interrupt processing while transmitting a command to the EFIECU 70 by communication to simultaneously control the gasoline engine 50.

Fig. 7 is a flowchart showing details of the control process of the clutch motor 30 executed in step S100 in the flowchart of Fig. 6. When the program enters the clutch motor control routine, the control CPU 90 of the controller 80 first reads the rotation angle θd of the drive shaft 22 from the resolver 48 in step S112 and the rotation angle θe of the crankshaft 56 of the gasoline engine 50 from the resolver in step S114. 39. The control CPU 90 then calculates a relative angle θc of the drive shaft 22 and the crankshaft 56 by the equation θc = θe - θd in step S116.

The program proceeds to step S118, in which the control CPU 90 receives data of the clutch motor currents Iuc and Ivc flowing through the U phase and the V phase, respectively, of the three-phase coils 36 in the clutch motor 30 from the ammeters 95 and 96. Although the currents naturally flow through all three phases U, V and W, measurement is only required for the currents passing through the two phases since the sum of the currents is zero. In the subsequent step S120, the control CPU 90 carries out coordinate conversion (conversion from three phases to two phases) using the values of the currents flowing through the three phases obtained in step S118. The coordinate conversion represents the values of the currents flowing through the three phases to the values of the currents flowing through the d and q axes of the permanent magnet synchronous motor and is carried out according to the following equation (1):

The coordinate conversion is performed because the currents flowing through the d and q axes are essential for the torque control in the permanent magnet synchronous motor. Alternatively, the torque control may be directly performed with the currents flowing through the three phases. After conversion into the currents of the two axes, the control CPU 90 calculates the deviations of the currents Idc and Iqc actually flowing through the d and q axes from the current control values Idc* and Iqc* of the respective axes calculated from the torque control value Tc* of the clutch motor 30, and determines the voltage control values Vdc and Vqc for the d and q axes in step S122.

According to a concrete procedure, the control CPU 90 performs the operation according to equations (2) and equations (3) given below:

ΔIdc = Ic* - Idc

ΔIqc = Iqc* - Iqc... (2)

Vdc = Kp1·ΔIdc + Sigma;Ki1·ΔIdc

Vqc = Kp2·ΔIqc + Sigma;Ki2·ΔIdc... (3)

where Kp1, Kp2, Ki1 and Ki2 represent coefficients that are set to suit the characteristics of the engine used.

The voltage setpoint Vdc (Vqc) has a part proportional to the deviation ΔI from the current setpoint I* (first term on the right-hand side of equation (3)) and a summation of the historical data of the deviations ΔI for 'i' times (second term on the right-hand side). The control CPU 90 then reverse converts the coordinates of the voltage setpoints thus obtained in step S124 (conversion from two phases to three phases). This is equivalent to an inversion of the conversion carried out in step S120. The reverse conversion determines voltages Vuc, Vvc and Vwc actually applied to the three-phase coils 36 as follows:

Vwc = -Vuc - Vvc ... (4)

The actual voltage control is carried out by the on-off operation of the transistors Tr1 to Tr6 in the first drive circuit. In step S126, the On and off times of the transistors Tr1 to Tr6 in the first drive circuit 91 are PWM (pulse width modulation) controlled to obtain the voltage command values Vuc, Vvc and Vwc determined by the above equation (4). This process enables the clutch motor 30 to mechanically transmit the target torque to the drive shaft 22.

Fig. 8 is a flowchart showing details of the control process of the auxiliary motor 40 executed in step S102 in the flowchart of Fig. 6. When the program enters the auxiliary motor control routine, the control CPU 90 first reads the rotation angle Ad of the drive shaft 22 from the resolver 48 in step S140 and takes in data of the auxiliary motor currents Iua and Iva flowing through the U-phase and the V-phase, respectively, of the three-phase coils 44 in the auxiliary motor 40 from the ammeters 97 and 98 in step S142. The control CPU 90 then carries out the coordinate conversion for the currents of the three phases in step S144, calculates voltage set values Vda and Vqa in step S146, and carries out the reverse conversion of the coordinates for the voltage set values in step S148. In the subsequent step S150, the control CPU 90 determines the on and off times of the transistors Tr11 to Tr16 in the second drive circuit 92 for PWM (pulse width modulation) control. The processing in steps S144 to S150 is similar to that carried out in steps S120 to S126 of the clutch motor control routine shown in the flow chart of Fig. 7.

The control of the gasoline engine 50 (step S104 in the flow chart of Fig. 6) is carried out in the following manner. In order to obtain a steady-state drive with the target engine torque Te* and the target engine speed Ne* (which were set in step S90 in Fig. 6), the control CPU 90 regulates the torque Te and the speed Ne of the gasoline engine 50 to achieve these to approach the target engine torque Te* and the target engine speed Ne*, respectively. According to a concrete procedure, the control CPU 90 sends a command to the EFIECU 70 by communication to regulate the amount of fuel injection or the throttle valve position. Such regulation causes the torque Te and the speed Ne of the gasoline engine SO to subsequently approach the target engine torque Te* and the target engine speed Ne*.

As described above, the power operation of the clutch motor 30 allows the drive shaft 22 to rotate at a speed higher than that of the crankshaft 56 of the gasoline engine 50. In the meantime, the auxiliary motor 40 performs the regenerative operation for regenerating electric energy supplied to the clutch motor 30 to compensate for the electric energy consumed by the clutch motor 30. As shown in Fig. 5, the energy in the region Ga regenerated as electric energy by the auxiliary motor 40 is consumed as the energy in the region Gc by the clutch motor 30. More specifically, the energy in the region Ga is converted to that in the region Gc.

There is, of course, a certain amount of energy loss in the clutch motor 30, auxiliary motor 40, first drive circuit 91 and second drive circuit 92. Accordingly, it is rare that the energy in the region Ga perfectly coincides with the energy in the region Gc in the actual state. However, the energy loss in the clutch motor 30 and auxiliary motor 40 is relatively small because some recently developed synchronous motors have an efficiency very close to 1. The energy loss in the first drive circuit 91 and second drive circuit 92 can also be sufficiently small because the on-state resistance of the known transistors such as GTOs applicable to Tr1 to Tr16 is very small.

While the clutch motor 30 applies the torque Tc to the drive shaft 22, the auxiliary motor 40 generates the torque Ta which acts inversely to the rotation of the drive shaft 22. The torque Td output from the drive shaft 22 is therefore equal to (Tc-Ta). In general, when the vehicle is continuously operated at high speed on the highway or highway, a large torque is not required for the output torque Td of the drive shaft 22 due to the inertia of the vehicle. Thus, no problem occurs even if the output torque Td is as small as (Tc-Ta). As described above, in order to keep the rotational speed Ne of the gasoline engine at a substantially constant level, the torque Tc of the clutch motor 30 is set equal to the torque Te of the gasoline engine 50.

Fig. 9(a) shows a flow of energy between the gasoline engine 50, the clutch motor 30 and the auxiliary motor 40. In Fig. 9, the arrow of the solid line shows a flow of mechanical energy and the arrow of the dashed line shows a flow of electrical energy.

As shown in Fig. 9(a), mechanical energy (TexNe) generated by the gasoline engine 50 is transmitted to the clutch motor 30. The clutch motor 30 also receives electrical energy in the range Ga (TaxNd) supplied from the auxiliary motor 40 and converts the electrical energy (TaxNd) into mechanical energy in the range Gc (TcxNc). Accordingly, the sum of the mechanical energy (TcxNc) and the mechanical energy (TexNe) transmitted from the gasoline engine 50 is transmitted from the clutch motor 30 to the auxiliary motor 40. The auxiliary motor 40 converts a part of the transmitted mechanical energy into electrical energy in the range Ga (TaxNd) and supplies the electrical energy (TaxNd) to the clutch motor 30. The rest (TdxNd) of the transmitted mechanical energy is output to the drive shaft 22.

The structure of the first embodiment allows the drive shaft 22 to rotate at a speed higher than that of the crankshaft 56 of the gasoline engine 50, i.e., causes the vehicle to drive in the overdrive state. This enables the gasoline engine 50 to be driven at a desired high efficiency without increasing the speed of the gasoline engine 50 (speed of the crankshaft 56) even in the high-speed drive state, thereby improving fuel consumption.

In the first embodiment described above, only the electric power regenerated by the auxiliary motor 40 is used for the power operation of the clutch motor 30 to implement the overdrive state. The electric power stored in the battery 94 included in the power output device 20 can also be used for the same purpose. When the battery 94 has sufficient remaining capacity, the control CPU 90 of the controller 80 allows the clutch motor 30 to implement the power operation using the electric power stored in the battery 94 as well as the electric power regenerated by the auxiliary motor 40. According to a concrete procedure, the control CPU 90 controls the first drive circuit 91 to allow both the electric power regenerated by the auxiliary motor 40 and the electric power stored in the battery 94 to be supplied to the clutch motor 30 via the first drive circuit 91. The clutch motor 30 performs the energy operation with the larger amount of electrical energy, thereby further increasing the speed of the drive shaft 22. In this case, an energy flow between the gasoline engine 50, the clutch motor 30, the auxiliary motor 40 and the battery as shown in Fig. 9(b).

On the other hand, when the battery 94 has a very small remaining capacity, the auxiliary motor 40 can be controlled to regenerate electric energy larger than the electric energy consumed by the clutch motor 30. With this structure, while a part of the electric energy regenerated by the auxiliary motor 40 is supplied to the clutch motor 30, the battery 94 is charged with the remaining regenerated energy. According to a concrete procedure, the control CPU 90 controls the first and second drive circuits 91 and 92 to charge the battery 94 with a part of the electric energy regenerated by the auxiliary motor 40. This structure enables the battery 94 to be charged with the remaining energy during the overdrive operation. In this case, a flow of energy between the gasoline engine 50, the clutch motor 30, the auxiliary motor 40 and the battery 94 is as shown in Fig. 9(c).

In contrast, when the battery 94 has been fully charged, further storage of electric charges in the battery 94 may cause problems. Under these conditions, it is preferable that the auxiliary motor 40 is controlled not to perform any further regenerative operation while the clutch motor 30 is controlled to perform the power operation only with the electric energy stored in the battery 94. According to a concrete procedure, the control CPU 90 controls the second drive circuit 92 to affect the regenerative operation of the auxiliary motor 40 while controlling the first drive circuit 91 to allow the electric energy stored in the battery 94 to be supplied to the clutch motor 30 via the first drive circuit 91 and to start the power operation of the clutch motor 30 with the electric energy thus supplied. This operation can reduce the remaining capacity of the battery 94 to an appropriate level.

The control CPU 90 determines the state of charge of the battery 94 based on the remaining capacity BRM of the battery 94 measured by the remaining capacity measuring device 99.

The power output device 20 of the first embodiment can be applied to another application given as a second embodiment of the present invention. The second embodiment carries out the overdrive control to exert the same effects as the conventional overdrive operation by the torque converter.

Fig. 10 is a flowchart showing a control process in the overdrive state executed by the control CPU 90 in the second embodiment. When the program enters the routine, the control CPU 90 of the controller 80 first acquires data of the rotational speed Nd of the drive shaft 22 in step S160 and data of the rotational speed Ne of the gasoline engine 50 in step S162. The rotational speed Ne of the gasoline engine 50 may be calculated from the rotational angle θe of the crankshaft 56 read by the resolver 39 or directly measured by the rotational speed sensor 76 mounted on the distributor 60. In the latter case, the control CPU 90 acquires data of the rotational speed Ne of the gasoline engine 50 by communicating with the EFIECU 70 which connects to the rotational speed sensor 76.

The speed Nd of the input shaft 22 read in step S160 is compared with a reference speed NOD for the overdrive operation in step S164. If the input speed Nd exceeds the reference speed NOD, the program goes to the following step S166. Otherwise, the program exits the routine of Fig. 10.

In step S166, the control CPU 90 determines the torque command value Tc* of the clutch motor 30 according to the rotational speed Nd of the drive shaft 22 read in step S160 and the rotational speed Ne of the gasoline engine 50 read in step S162. The torque command value Tc* of the clutch motor 30 may be determined according to one of the characteristic curves previously stored in the ROM 90b as shown in Fig. 11 or, alternatively, by calculation.

In the former method, a plurality of characteristic curves representing the relationship between the speed difference (Nd-Ne) and the torque Tc of the clutch motor 30 are prepared for different values of the speed Nd of the drive shaft 22 as shown in Fig. 11. An appropriate characteristic curve corresponding to the input speed Nd of the drive shaft 22 is selected from those previously stored in the ROM 90b. The torque command value Tc* of the clutch motor 30 is then read against the speed difference (Ne-Nd) in the selected characteristic curve. The characteristic curves applicable to the overdrive control are those in the second quadrant (filled with oblique lines) in Fig. 11.

In the latter method, for example, equation (5) given below is used for the calculation:

Tc = Kc{(Ne - Nd) - KddxNd} (5)

where Kc denotes an efficiency corresponding to the slope of the curve in the graph of Fig. 11, and Kdd represents a constant corresponding to the coefficient for determining the ordinate intercept of the curve with respect to a given speed Nd.

The processing performed in the subsequent steps S168 to S178 is identical to that in steps S94 to S104 of Fig. 6 in the first embodiment.

As described above, the overdrive controller of the second embodiment determines the torque command value Tc* of the clutch motor 30 based on the input data of the rotational speed Nd of the drive shaft 22 and the rotational speed Ne of the gasoline engine 50 according to the characteristic curves as shown in Fig. 11 or by the calculation of equation (5) as given above.

For example, assume that the vehicle is driven at a constant speed and the drive shaft 22 rotates at a constant speed Nd (e.g., Nd=Nd3 in Fig. 11). When the driver steps on the accelerator pedal 64 to increase the output torque (torque of the drive shaft 22) to increase the vehicle speed, the gasoline engine 50 is controlled to increase its speed Ne. The difference (Ne-Nd) between the speed Nd of the drive shaft 22 and the speed Ne of the gasoline engine 50 accordingly approaches zero. Since the characteristic curve of the given speed Nd3 has a positive gradient as clearly seen in Fig. 11, the clutch motor 30 is controlled to increase its torque Tc as the speed difference (Ne-Nd) approaches zero. That is, the torque control value Tc* is set to a large value. With an increase in the torque Tc of the clutch motor 30, the drive shaft 22 is driven to rotate faster with respect to the crankshaft 56 of the gasoline engine 50. This increases the rotational speed Nd of the drive shaft 22 and accordingly improves the vehicle speed. By increasing the rotational speed Nd, the speed difference is removed (Ne-Nd) from zero, so that the clutch motor 30 is controlled to reduce its torque Tc. That is, the torque command value Tc* is set to a small value. The structure of the second embodiment determines the torque command value Tc* of the clutch motor 30 in the above manner, thereby implementing the continuous overdrive control.

In contrast, when the driver does not request an increase in the output torque (torque of the drive shaft 22) and releases the accelerator pedal 64, the gasoline engine 50 is controlled to reduce its speed Ne. The difference (Ne-Nd) between the speed Nd of the drive shaft 22 and the speed Ne of the gasoline engine 50 accordingly moves away from zero. The change in the speed difference (Ne-Nd) away from zero controls the clutch motor 30 to reduce its torque Tc according to the characteristic curve shown in Fig. 11. This means that the torque control value Tc* is set to a small value. As the torque Tc of the clutch motor 30 decreases, the output torque (torque of the drive shaft 22) therefore decreases.

The overdrive control of the second embodiment has the same effects as the conventional overdrive operation by the torque converter. A plurality of characteristic curves are prepared for the different values of the rotational speed Nd of the drive shaft 22 in Fig. 11. The characteristic curve with a large ordinate intersection is set for the high rotational speed Nd of the drive shaft 22 (ie, Nd=Nd3). This increases the torque Tc of the clutch motor 30 to prevent the gasoline engine 50 from speeding up when the rotational speed difference (Ne-Nd) approaches zero. The characteristic curve with a small ordinate intersection is set for the low rotational speed Nd of the drive shaft 22 (ie, Nd=Nd1). This decreases the torque Tc of the clutch motor 30 to allow the gasoline engine 50 to start up when the speed difference (Ne-Nd) approaches zero.

The power output device 20 of the first embodiment can be put into still another application, which is given as a third embodiment of the present invention. In the first embodiment, the auxiliary motor 40 is controlled to perform the regenerative operation and to regenerate electric energy that compensates for the electric energy consumed by the clutch motor 30. The regenerative operation of the auxiliary motor 40 generates the negative torque Ta, which is added to the positive torque Tc generated by the clutch motor 30, and thereby causes the torque Td (=Tc-Ta) output to the drive shaft 22 to be relatively small. This may cause insufficient output torque Td in the case where the large torque is required, for example, when the vehicle comes to a slope or when the driver wants to overtake another vehicle while driving at high speed on the highway or highway.

In the structure of the third embodiment, not only the clutch motor 30 but also the auxiliary motor 40 are controlled to perform the power operation in cases where a large output torque Td of the drive shaft 22 is required. In this structure, the electric power required for the power operation in both the clutch motor 30 and the auxiliary motor 40 is supplied from the battery 94.

Fig. 12 is a flow chart showing a control process in the overdrive state executed by the control CPU 90 in the third embodiment. When the program enters the routine, the control CPU 90 of the controller 80 first takes in data in step S180 the rotational speed Nd of the drive shaft 22 and, in step S182, data of the rotational speed Ne of the gasoline engine 50.

The speed Nd of the drive shaft 22 read in step S180 is compared with a reference speed NOD for the overdrive operation in step S184. If the input speed Nd exceeds the reference speed NOD, the program goes to the following step S186. Otherwise, the program exits the routine of Fig. 12.

The control CPU 90 reads the accelerator pedal position AP from the accelerator pedal position sensor 65 in step S186 and calculates the output torque setpoint Td* (torque of the drive shaft 22) corresponding to the input accelerator pedal position AP in step S188.

The output torque set value Td* calculated in this way is compared with a reference output torque TdST in step S190. An appropriate value has been set as the reference output torque TdST in view of determining whether the driver requests a large output torque Td. In step S190, it is determined whether the output torque set value Td* representing the desired output torque requested by the driver exceeds the preset reference output torque TdST. If the output torque setpoint Td* does not exceed the reference output torque TdST, the program determines that the driver does not request a large output torque and that no specific control is required to enable the power operation of the assist motor 40 and the clutch motor 30, and exits the routine of Fig. 12.

On the other hand, when the output torque set value Td* exceeds the reference output torque TdST, the control CPU 90 determines the torque set value Tc* of the clutch motor 30 and the torque set value Ta* in step S192. of the auxiliary motor 40 based on the output torque set value Td*. The torque set values Tc* and Ta* are set to satisfy the following two conditions:

(1) The sum of the torque control value Tc* of the clutch motor 30 and the torque control value Ta* of the auxiliary motor 40 is equal to the output torque control value Td* (Tc* + Ta* = Td*), which represents the desired output torque required by the driver, and

(2) The sum of the energy operation efficiency ksc of the clutch motor 30 and an energy operation efficiency ksa of the auxiliary motor 40 gives a maximum efficiency.

The best operating point of each engine for obtaining maximum power operation efficiency can be read from an efficiency graph as shown in the characteristic graph of Fig. 13. For example, operating points of 90% and 92% power operation efficiency of the engine exist on a 90% efficiency curve and a 92% efficiency curve in Fig. 13, respectively. Since each engine follows its own efficiency graph, different efficiency graphs should be used for the clutch motor 30 and the auxiliary motor 40. The rotational speed Nc of the clutch motor 30 is given as the difference (Nd-Ne) between the rotational speed Nd of the drive shaft 22 read in step S180 and the rotational speed Ne of the gasoline engine 50 (rotational speed of the crankshaft 56) read in step S182. The speed Na of the auxiliary motor 40 is identical to the speed Nd of the drive shaft 22. For example, if the efficiency graph of Fig. 13 is applied to the auxiliary motor 40, the auxiliary motor 40 rotating at the speed Na=Nd gives a 90% efficiency of the energy operation ksa at torque Ta=Ta1 and 92% efficiency at torque Ta=Ta2. The torque Tc that achieves the maximum efficiency at the speed (Nd-Nc) is read from the efficiency graph of the clutch motor 30 and assigned to the torque set value Tc* of the clutch motor 30. The torque Ta that achieves the maximum efficiency at the speed Nd is read from the efficiency graph of the auxiliary motor 40 and assigned to the torque set value Ta* of the auxiliary motor 40. The torque set values Tc* and Ta* set in this way can satisfy the above condition (2).

When the clutch motor 30 and the auxiliary motor 40 consume almost the same amount of electric power, the satisfied condition (2) ensures the substantially minimum amount of electric power consumed by the clutch motor 30 and the auxiliary motor 40. In contrast, when the clutch motor 30 and the auxiliary motor 40 consume substantially different amounts of electric power, the satisfied condition (2) cannot ensure the minimum amount of energy consumed by the clutch motor 30 and the auxiliary motor 40. This may occur, for example, in the case where the electric power consumed by the clutch motor 30 is significantly larger than the electric power consumed by the auxiliary motor 40. Under such conditions, the sum of the electric energy consumed by the clutch motor 30 and the auxiliary motor 40 can be minimized not at the operating point that achieves the high efficiencies of both the clutch motor 30 and the auxiliary motor 40, but at the operating point that achieves the higher efficiency of the clutch motor 30 but the relatively lower efficiency of the auxiliary motor 40. However, the consumed energy of the clutch motor 30 is substantially identical to that of the auxiliary motor 40 in general. Therefore, if the above condition (2) is satisfied, the The sum of the electrical energy consumed by the clutch motor 30 and the auxiliary motor 40 is minimized.

The control CPU 90 calculates the total electric energy Pm consumed by the clutch motor 30 and the assist motor 40 from the torque command values Tc* and Ta* set in step S192 in step S194. The electric energy Pc consumed by the clutch motor 30 is given by:

Pc = (1/ksc) Tc* (Nd - Nc)

while the electrical energy Pa consumed by the auxiliary motor 40 is expressed as:

Pa = (1/ksa) · Ta* · Nd.

The total electrical energy Pm consumed by the two motors 30 and 40 is thus given as:

Pm = Pc + Pa

The program then goes to step S196, in which the remaining capacity BRM of the battery 94 measured by the remaining capacity measuring device 99 is compared with a reference value BPm which is changed depending on the total consumed energy Pm. As described above, the electric energy stored in the battery 94 should cover the total electric energy Pm consumed by the clutch motor 30 and the auxiliary motor 40. It is thus necessary that the battery 94 has sufficient remaining capacity to cover the total consumed energy Pm. In step S196, it is determined whether the remaining capacity BRM of the battery 94 is larger than the reference value BPm which has been set in accordance with the total consumed energy Pm. This shows whether the remaining capacity BRm of the battery 94 is sufficient to cover the consumed total energy Pm. If the remaining capacity BRM of the battery 94 is not greater than the reference value BPm and is not sufficient to cover the consumed total energy Pm, the program exits the routine of Fig. 12.

On the other hand, when the remaining capacity BRM of the battery 94 is larger than the reference value BPm, the program goes to step S198 to control the clutch motor 30, to step S200 to control the auxiliary motor 40, and to step S202 to control the gasoline engine 50. The control procedures of the clutch motor 30 and the auxiliary motor 40 are similar to those of Figs. 7 and 8 in the first embodiment. However, unlike the first embodiment, the auxiliary motor 40 is controlled to perform not the regenerative operation but the power operation in the third embodiment. Note that the torque generated by the auxiliary motor 40 in the third embodiment acts in the opposite direction to the torque generated in the first embodiment, i.e., in the direction of rotation of the drive shaft 22, and the torque control value Ta* has an inverted sign. The gasoline engine 50 is controlled to be driven at the highest possible efficiency. For convenience of illustration, the control operations of the clutch motor 30, the auxiliary motor 40 and the gasoline engine 50 are shown as separate steps. In the actual procedure, these control operations are carried out in complex. For example, the control CPU 90 simultaneously controls the clutch motor 30 and the auxiliary motor 40 by interrupt processing, while at the same time transmitting a command to the EFIECU 70 by communication to control the gasoline engine 50 simultaneously.

Fig. 14 is a graph showing an amount of energy consumed by the clutch motor 30 and an amount of energy consumed by the auxiliary motor 40 according to the control procedure of Fig. 12. The gasoline engine 50 driven at an engine speed Ne and an engine torque Te outputs power in a range Ge. The clutch motor 30 consumes power in a range Gc supplied as electric power from the battery 94 and performs the power operation to allow the drive shaft 22 to rotate at the speed Nd higher than the speed Ne of the crankshaft 56 of the gasoline engine 50. The auxiliary motor 40 consumes power in a range Ga supplied as electric power from the battery 94 and performs the power operation to increase the output torque Td of the drive shaft 22 by the torque Ta generated by the auxiliary motor 40.

Fig. 15 shows a flow of energy between the gasoline engine 50, the clutch motor 30, the auxiliary motor 40, and the battery 94. The mechanical energy (TexNe) in the region Ge generated by the gasoline engine 50 is transmitted to the clutch motor 30. The clutch motor 30 converts the electrical energy in the region Gc (TcxNc) supplied from the battery 94 into mechanical energy and adds the converted mechanical energy to the mechanical energy in the region Ge (TexNe) transmitted from the gasoline engine 50. The sum of the mechanical energy (TcxNd) is accordingly transmitted from the clutch motor 30 to the auxiliary motor 40. The auxiliary motor 40 converts electrical energy in the range Ga (TaxNd) into mechanical energy and adds the converted mechanical energy to the mechanical energy (TcxNd) transmitted from the clutch motor 30. The total mechanical energy (TdxNd) is then output to the drive shaft 22.

The process of the third embodiment allows both the clutch motor 30 and the auxiliary motor 40 to perform the power operation. The drive shaft 22 accordingly takes the sum of the torque Tc generated by the clutch motor 30 and the torque Ta generated by the assist motor 40, both acting in the rotational direction of the drive shaft 22. This results in a large output torque Td of the drive shaft 22 which is equal to (Tc+Ta). The structure of the third embodiment is preferable in the case where the large output torque Td is required, for example, when the vehicle is going on a slope or when the driver wants to overtake another vehicle while driving at high speed on the highway or highway.

The clutch motor 30 and the auxiliary motor 40 are controlled to maximize the sum of the power operation efficiency ksc of the clutch motor 30 and the power operation efficiency ksa of the auxiliary motor 40. This effectively reduces the energy loss in the clutch motor 30 and auxiliary motor 40 and realizes the substantially minimum sum of the electric energy consumed by the clutch motor 30 and the auxiliary motor 40, thereby improving the fuel consumption of the gasoline engine 50.

Some examples of modifications to the above embodiments are listed below.

In the structure of the power output device 20 shown in Fig. 1, the clutch motor 30 and the auxiliary motor 40 are separately attached to different positions of the drive shaft 22. However, as in a modified power output device 20A shown in Fig. 16, the clutch motor and the auxiliary motor may be integrally connected to each other. A clutch motor 30A of the power output device 20A has an inner rotor 34 that connects to the crankshaft 56 and an outer rotor 32A that connects to the drive shaft 22. Three-phase coils 36 are attached to the inner rotor 34 and permanent magnets 35A are attached to the outer rotor 32A in such a manner that are arranged such that the outer surface and the inner surface thereof have different magnetic poles. An auxiliary motor 40A comprises the outer rotor 32A of the clutch motor 30A and a stator 43 on which three-phase coils 44 are mounted. In this structure, the outer rotor 32A of the clutch motor 30A also functions as a rotor of the auxiliary motor 40A. Since the three-phase coils 36 are mounted on the inner rotor 34 which connects to the crankshaft 56, a rotary converter 38 for supplying power to the three-phase coils 36 of the clutch motor 30A is fixed to the crankshaft 56.

In the power output device 20A, the voltage applied to the three-phase coils 36 on the inner rotor 34 is controlled with respect to the inner surface magnetic pole of the permanent magnets 35A arranged on the outer rotor 32A. This enables the clutch motor 30A to operate in the same manner as the clutch motor 30 of the power output device 20 shown in Fig. 1. The voltage applied to the three-phase coils 44 on the stator 43 is controlled with respect to the outer surface magnetic pole of the permanent magnets 35A arranged on the outer rotor 32A. This enables the auxiliary motor 40A to operate in the same manner as the auxiliary motor 40 of the power output device 20. The control procedures discussed as the first to third embodiments above are applicable to the power output device 20A shown in Fig. 16, which accordingly has the same effects as the power output device 20 shown in Fig. 1.

In the energy output device 20A of Fig. 16, the clutch motor 30A and the auxiliary motor 40A are integrally connected to each other, which shortens the length of the energy output device 20A along the drive shaft 22. The outer rotor 32A simultaneously functions as one of the rotors in the clutch motor 30A and as the rotor of the auxiliary motor 40A, thereby effectively reducing the size and weight of the entire energy delivery device 20A.

In the modified structure in which the outer rotor 32A functions as one of the rotors in the clutch motor 30A and as the rotor of the auxiliary motor 40A, the clutch motor 30A and the auxiliary motor 40A are caused to magnetically interfere with each other and thereby have a negative effect on each other. In order to prevent the large magnetic interference, the outer rotor 32A may be constructed as a double cylinder structure having two concentric cylinders. One of the cylinders is associated with the rotor of the clutch motor 30A and the other with the rotor of the auxiliary motor 40A. The two cylinders, which are spaced apart by a predetermined distance, are connected to the drive shaft 22. A magnetic shield member for blocking the magnetic lines of force is also effective in preventing the magnetic interference.

Although the auxiliary motor 40 is attached to the drive shaft 22 in the power output device 20 of Fig. 1, in another power output device 20B shown in Fig. 17, an auxiliary motor 40B may be attached to the crankshaft 56 of the gasoline engine 50.

The power output device 20B of Fig. 17 has a similar structure to the power output device 20 of Fig. 1, except that the auxiliary motor 40B is attached to the crankshaft 56, which is located between the gasoline engine 50 and a clutch motor 30B. In the power output device 20B of Fig. 17, similar elements to those in the power output device 20 of Fig. 1 are shown by the same reference numerals or symbols and will not be explained here. The symbols used in the above description have a similar meaning unless otherwise specified.

The operation of the power output device 20B shown in Fig. 17 will be described below. For example, it is assumed that the gasoline engine 50 is driven with a torque Te and a speed Ne. When a torque Ta is added to the crankshaft 56 by the auxiliary motor 40B connected to the crankshaft 56, the sum of the torques (Te+Ta) therefore acts on the crankshaft 56. When the clutch motor 30B is controlled to generate the torque Tc equal to the sum of the torques (Te+Ta), the torque Tc (=Te+Ta) is then transmitted from the clutch motor 30B to the drive shaft 22.

When the vehicle is driven in a normal driving state, that is, when the rotational speed Nd of the drive shaft 22 is lower than the rotational speed Ne of the gasoline engine 50 (Nd< Ne), the clutch motor 30B regenerates electric energy based on the rotational speed difference Nc between the rotational speed Ne of the gasoline engine 50 and the rotational speed Nd of the drive shaft 22. The regenerated energy is supplied to the auxiliary motor 40B via the first and second drive circuits 91 and 92 to activate the auxiliary motor 40B. Assuming that the torque Ta of the auxiliary motor 40B is set to a value that allows the auxiliary motor 40B to consume electric energy substantially identical to the electric energy regenerated by the clutch motor 30B, free torque conversion for the energy output from the gasoline engine 50 is permitted within a range that satisfies the relationship of the following equation (6). Since the relationship of the equation (6) represents the ideal state with an efficiency of 100%, (TcxNd) is a little smaller than (TexNe) in the actual state:

Te · Ne = Tc · Nd (6)

Fig. 18 is a graph schematically showing an amount of energy regenerated by the clutch motor 30B and an amount of energy consumed by the auxiliary motor 40B. In the example of Fig. 18, the crankshaft 56 of the gasoline engine 50 is driven at a speed Ne and a torque Te, while the drive shaft 22 is driven at a speed Nd and a torque Td. The clutch motor 30B regenerates energy in a range Gc as electric energy. The regenerated energy is supplied to the auxiliary motor 40B as energy in a range Ga, which is consumed by the auxiliary motor 40B.

When the vehicle is driven at high speed on the highway or highway, that is, when the rotational speed Nd of the drive shaft 22 is higher than the rotational speed Ne of the gasoline engine 50 (Nd>Ne), the clutch motor 30B operates as a normal motor. The clutch motor 30B accordingly improves the rotational speed of the inner rotor 34 with respect to the outer rotor 32. Assuming that the torque Ta of the auxiliary motor 40B is set to a negative value to allow the auxiliary motor 40B to generate power substantially equivalent to the electric power consumed by the clutch motor 30B, free torque conversion for the power output from the gasoline engine 50 is also enabled within a range satisfying the relationship of the above equation (6).

With only a slight modification, the control procedures discussed above as the first to third embodiments are also applicable to the energy output device 20B shown in Fig. 17, which accordingly has the same effects as the energy output device 20 shown in Fig. 1. The required modification of the control procedures will be briefly described.

When the control procedure of the first embodiment is executed by the power output device 20 of Fig. 1, the torque command value Tc* of the clutch motor 30 is set equal to the target engine torque Te* in step S92 in the flowchart of Fig. 6. However, in the power output device 20B of Fig. 17, the torque command value Tc* of the clutch motor 30B should be set equal to the output torque command value Td*.

The torque control value Ta* of the assist motor 40 is calculated in step S98 of Fig. 6 in the first embodiment or in step S172 of Fig. 10 in the second embodiment according to the equation expressed as follows:

Ta* = Pa/(KsaxNd)

For the energy delivery device 20B of Fig. 17, the calculation should be changed to:

Ta* = Pa/(KsaxNe)

While in the structure of the first embodiment, the power output device 20 of Fig. 1 has the energy flow shown in Fig. 9, the power output device 20B of Fig. 17 outputs a different energy flow. More specifically, in the power output device 20B, the energy flow shown in Fig. 9 is changed to the energy flow shown in Fig. 19. In the power output device 20B as shown in Fig. 19, the mechanical energy (TexNe) generated by the gasoline engine 50 is first transmitted to the auxiliary motor 40B. The auxiliary motor 40B converts a part of the transmitted mechanical energy into electrical energy (TaxNe) and supplies the converted electrical energy (TaxNe) to the clutch motor 30B, while the remaining mechanical energy Energy (TdxNe) is directly transmitted to the clutch motor 30B. The clutch motor 30B converts the electrical energy (TaxNe) supplied from the auxiliary motor 40B into mechanical energy (TcxNc) and adds the converted mechanical energy (TcxNc) to the remainder of the mechanical energy (TdxNe) transmitted from the auxiliary motor 40B. The total mechanical energy (TdxNd) is then output to the drive shaft 22.

When the control procedure of the third embodiment is carried out by the power output device 20 of Fig. 1, the torque command value Tc* of the clutch motor 30 and the torque command value Ta* of the auxiliary motor 40 are set to satisfy the two specific conditions discussed above in step S192 in the flow chart of Fig. 12. However, in the power output device 20B of Fig. 17, the torque command value Tc* of the clutch motor 30 should be set equal to the output torque command value Td*. The torque command value Ta* of the auxiliary motor 40 should be set to satisfy the following equation and realize the maximum power operation efficiency ksa:

Ta* + Te* = Td*

where Te* represents a target engine torque or a torque setpoint of the gasoline engine 50. The target engine torque Te* of the gasoline engine 50 should be set to satisfy the above equation and realize the highest possible efficiency. The target engine torque Te* of the gasoline engine 50 is used in the process of controlling the gasoline engine 50 in step S202 in the flowchart of Fig. 12.

The electric power Pa consumed by the auxiliary motor 40 is calculated in step S194 of Fig. 12 in the third Example calculated according to the equation which is expressed as follows:

Pa = (1/ksa) · Ta* · Nd

For the energy delivery device 20B of Fig. 17, the calculation should be changed to:

Pa = (1/ksa) · Ta* · Ne

In the structure of the third embodiment, while the power output device 20 of Fig. 1 has the energy flow shown in Fig. 15, the power output device 20B of Fig. 17 outputs a different energy flow. The clutch motor 30B and the auxiliary motor 40B switch places in the drawing of Fig. 15. In the power output device 20B, the mechanical energy in the region Ge (TexNe) generated by the gasoline engine 50 is first transmitted to the auxiliary motor 40B. The auxiliary motor 40B converts the electric energy (TaxNd) supplied from the battery 94 into mechanical energy and adds the converted mechanical energy to the mechanical energy in the region Ge (TexNe) transmitted from the gasoline engine 50. The sum of the mechanical energy (TdxNe) is accordingly transmitted from the auxiliary motor 40B to the clutch motor 30B. The clutch motor 30B converts the electrical energy (TcxNc) supplied from the battery 94 into mechanical energy and adds the converted mechanical energy to the mechanical energy (TdxNe) transmitted from the auxiliary motor 40B. The total mechanical energy (TdxNd) is then output to the drive shaft 22.

The modifications discussed above enable the energy output device 20B of Fig. 17 to implement the first to third embodiments and have the same effects.

In the power output device 20B of Fig. 17, the auxiliary motor 40B is fixed to the crankshaft 56, which is located between the gasoline engine 50 and the clutch motor 30B. However, as with another power output device 20C shown in Fig. 20, the gasoline engine 50 may be interposed between a clutch motor 30C and an auxiliary motor 40C fixed to the crankshaft 56. The control procedures performed by the power output device 20B of Fig. 17 are also applicable to the power output device 20C, which accordingly implements the same operations and effects.

In the power output device 20B of Fig. 17, the clutch motor 30B and the auxiliary motor 40B are separately fixed to different positions of the crankshaft 56. As in a power output device 20D shown in Fig. 21, however, a clutch motor 30D and an auxiliary motor 40D may be integrally connected to each other, the clutch motor 30D of the power output device 20D has an outer rotor 32D connecting to the crankshaft 56, and an inner rotor 34 connected to the drive shaft 22. Three-phase coils 36 are fixed to the inner rotor 34, and permanent magnets 35D are arranged on the outer rotor 32D in such a manner that the outer surface and the inner surface thereof have different magnetic poles. The auxiliary motor 40D includes the outer rotor 32D of the clutch motor 30D and a stator 43 on which three-phase coils 44 are mounted. In this structure, the outer rotor 32D of the clutch motor 30D also functions as a rotor of the auxiliary motor 40D.

In the energy output device 20D, the voltage applied to the three-phase coils 36 on the inner rotor 34 is controlled relative to the inner surface magnetic pole of the permanent magnets 35D arranged on the outer rotor 32D.

This enables the clutch motor 30D to operate in the same manner as the clutch motor 30B of the power output device 20B shown in Fig. 17. The voltage applied to the three-phase coils 44 on the stator 43 is controlled with respect to the outer surface magnetic pole of the permanent magnets 35D arranged on the outer rotor 32D. This enables the auxiliary motor 40D to operate in the same manner as the auxiliary motor 40B of the power output device 20B. The control procedures of the first to third embodiments discussed above are also applicable to the power output device 20D shown in Fig. 21, which accordingly has the same effects as the power output device 20B shown in Fig. 17.

As with the power output device 20A of Fig. 16, in the power output device 20D of Fig. 21, the clutch motor 30D and the auxiliary motor 40D are integrally connected to each other, which shortens the length of the power output device 20D along the drive shaft 22. The outer rotor 32D simultaneously functions as one of the rotors in the clutch motor 30D and the rotor of the auxiliary motor 40D, thereby effectively reducing the size and weight of the entire power output device 20D.

In all the structures of Figs. 1, 16, 17, 20 and 21, the power output device includes the auxiliary motor 40 and the clutch motor 30. However, the overdrive control can be implemented by the structure of Fig. 1 without the auxiliary motor 40. In this modified structure without the auxiliary motor 40, the clutch motor 30 is controlled to perform the power operation using the electric energy stored in the battery 94. This allows the drive shaft 22 to rotate at a speed higher than that of the crankshaft 56 of the gasoline engine 50 and the torque identical to the engine torque of the gasoline engine 50 to be output. According to a concrete procedure the control CPU 90 controls the first drive circuit 91 to supply electric power stored in the battery 94 to the clutch motor 30 via the first drive circuit 91 and to cause the clutch motor 30 to perform the power operation so that the drive shaft 22 rotates at a speed higher than that of the crankshaft 56.

Fig. 22 shows a flow of energy between the gasoline engine 50, the clutch motor 30, and the battery 94. Mechanical energy generated by the gasoline engine 50 is transmitted to the clutch motor 30. The clutch motor 30 converts electrical energy supplied from the battery 94 into mechanical energy and adds the converted mechanical energy to the mechanical energy transmitted from the gasoline engine 50. The sum of the mechanical energy is accordingly output from the clutch motor 30 to the drive shaft 22.

The gasoline engine 50 driven by gasoline is used as an internal combustion engine in the above power output devices. However, the principle of the invention is applicable to other internal combustion engines and other external combustion engines, such as diesel engines, turbine engines and jet engines.

In the energy delivery devices described above, permanent magnet (PM) synchronous motors are used for the clutch motor 30 and the auxiliary motor 40. For both regenerative operation and energy operation, other motors such as variable reluctance (VR) synchronous motors, fine-tuning motors, DC motors, induction motors and superconducting motors can be used, while stepper motors are only applicable for energy operation.

In the embodiments discussed above, the outer rotor 32 of the clutch motor 30 is connected to the crankshaft 56, while the inner rotor 34 is connected to the drive shaft 22. Alternatively, the outer rotor 32 can be connected to the drive shaft 22 and the inner rotor 34 to the crankshaft 56. Instead of the outer rotor 32 and the inner rotor 34, disc rotors that face each other can be used.

The rotary converter 38 used as a means for transmitting electric energy to the clutch motor 30 may be replaced by a slip ring-brush contact, a slip ring-mercury contact, a semiconductor clutch with magnetic energy or the like.

In the above power output devices, transistor inverters are used for the first and second drive circuits 91 and 92. Other examples usable for the drive circuits 91 and 92 include IGBT inverters (Insulated Gate Bipolar Transistor inverters), thyristor inverters, voltage PWM (Pulse Width Modulation) inverters, square wave inverters (voltage inverters and current inverters), and resonance inverters.

The battery 94 may comprise Pb cells, NiMH cells, Li cells, or similar cells. A capacitor may be used instead of the battery 94. The battery 94 also functions as a means for absorbing the regenerated energy. A variety of electrical equipment (e.g., lighting equipment, sound equipment, and cooling equipment) mounted on the vehicle other than the battery 94 may be used as a means for absorbing regenerated energy.

Although the energy delivery device is mounted on the vehicle in the above embodiments, it can be mounted on other transport devices such as ships and aircraft and can be mounted on a variety of industrial machines.

The scope of the present invention is limited by the content of the appended claims.

Claims (15)

1. Energy delivery device for delivering energy to a drive shaft (22), the energy delivery device comprising: an internal combustion engine (50) with an output shaft (56), a first motor (30) with a first rotor connected to the output shaft (56) of the internal combustion engine and a second rotor connected to the drive shaft (22), the second rotor being arranged coaxially and rotatably with respect to the first rotor and the first and second rotors being electromagnetically coupled to one another, whereby energy is transmitted between the output shaft (56) of the internal combustion engine and the drive shaft (22) via the electromagnetic coupling of the first and second rotors, a drive device (91) for the first motor for exchanging electrical currents with the first motor (30) in order to change the electromagnetic coupling of the first rotor with the second rotor, a second motor (40) having a stator and a third rotor connected to either the drive shaft (22) or the output shaft (56) of the internal combustion engine, the stator being electromagnetically coupled to the third rotor, and a drive device (92) for the second motor for exchanging electrical currents with the second motor, in order to change the electromagnetic coupling of the stator with the third rotor, marked by a control device (90) for controlling the drive circuit for the first and second motors to adjust the speeds of the drive shaft (22) and the output shaft (56) of the internal combustion engine so that the speed the drive shaft (22) is higher than the speed of the output shaft (56). 2. The power output device according to claim 1, wherein the control means (90) comprises means for controlling the drive circuit (92) for the second motor to enable the second motor (40) to generate electrical energy and for controlling the drive circuit (91) for the first motor to supply the generated electrical energy to the first motor (30) for driving the first motor. 3. Energy delivery device according to claim 1, wherein the energy delivery device further comprises: a storage device (94) for storing electrical energy and wherein the control device (90) comprises means for controlling the drive device (92) for the second motor to enable the second motor (40) to generate electrical energy and for controlling the drive circuit (91) for the first motor to supply the generated electrical energy and the electrical energy stored in the storage device (94) to the first motor (30) to drive the first motor. 4. The energy delivery device of claim 1, wherein the energy delivery device further comprises: a storage device (90) for storing electrical energy, and wherein the control device (90) comprises means for controlling the drive circuit (92) for the second motor to enable the second motor (40) to generate electrical energy and for controlling the drive circuit (91) for the first motor to supply the generated electrical energy to the first motor (30) for driving the first motor and at least partially to the storage device (90) for storing it. 5. The energy delivery device of claim 1, wherein the energy delivery device further comprises: a storage device (94) for storing electrical energy, and wherein the control device (90) comprises means for controlling the drive device (91) for the first motor, in order to supply the electrical energy from the storage device to the first motor (30) for driving the first motor. 6. The energy delivery device of claim 1, wherein the energy delivery device further comprises: a storage device (94) for storing electrical energy, and wherein the control device (90) comprises means for controlling the drive circuit (92) for the second motor to supply electrical energy from the storage device (94) to the second motor (40) for driving the second motor, and for controlling the drive circuit (91) for the first motor to supply electrical energy from the storage device (94) to the first motor (30) for driving the first motor. 7. A power output device according to claim 6, wherein the control means (90) comprises means for controlling the drive circuit (91) for the first motor and the drive circuit (92) for the second motor to drive the first motor (30) and the second motor (40) so that a sum of electric power consumed by the first motor (30) and the second motor (40) is minimized under a specified condition. 8. An energy output device according to claim 7, wherein the control means (90) comprises means for controlling the drive circuit (91) for the first motor and the drive circuit (92) for the second motor to drive the first motor (30) and the second motor (40), so that an overall efficiency of the first motor and the second motor is maximized under a specified condition. 9. Energy delivery device according to one of the preceding claims, wherein the third rotor is mounted on the second rotor, which is connected to the drive shaft (22) connected to the third rotor, or mounted on the first rotor, which is connected to the output shaft (56) connected to the third rotor. 10. A method for controlling an energy delivery device for delivering energy to a drive shaft (22), the method comprising the steps of: (a) providing an internal combustion engine (50) with an output shaft (56), a first motor (30) with a first rotor connected to the output shaft (56) of the internal combustion engine and a second rotor connected to the drive shaft (22), wherein the second rotor is arranged coaxially and rotatably with respect to the first rotor and wherein the first and second rotors are electromagnetically coupled to one another, whereby energy is transmitted between the output shaft (56) of the internal combustion engine and the drive shaft (22) via the electromagnetic coupling of the first and second rotors, a second motor (40) with a stator and a third rotor which is connected to the drive shaft (22) or the output shaft (56), wherein the stator is electromagnetically coupled to the third rotor, characterized by the step of (b) adjusting the speeds of the drive shaft (22) and the output shaft (56) of the internal combustion engine by a control device (90) which controls the first motor (30) and the second motor (40) so that the speed of the drive shaft (22) is higher than the speed of the output shaft (56). 11. The method of claim 10, wherein step (b) comprises the steps: (b-1) enabling the second motor (40) to generate electrical energy, and (b-2) Supplying the generated electrical energy to the first motor (30) for driving the first motor. 12. The method of claim 10, wherein step (a) comprises the step of providing a storage device (94) for storing electrical energy, and wherein step (b) comprises the steps of: (b-1) enabling the second motor (40) to generate electrical energy, and (b-2) supplying the generated electrical energy and the electrical energy stored in the storage device (94) to the first motor for driving the first motor (30). 13. Method according to claim 10, wherein step (a) comprises the step of providing a storage device (94) for storing electrical energy, and step (b) comprises the steps: (b-1) enabling the second motor (40) to generate electrical energy, and (b-2) supplying the generated electrical energy to the first motor (30) for driving the first motor and at least partially to the storage device (94) for storage. 14. The method of claim 10, wherein step (a) comprises the step of providing a storage device (94) for storing electrical energy, and step (b) comprises the step of supplying the electrical energy from the storage device (94) to the first motor (30) for driving the first motor. 15. A method for controlling an energy delivery device according to claim 10, wherein step (a) comprises the step of providing a storage device (94) for storing electrical energy, and Step (b) comprises the steps: (b-1) supplying the electrical energy from the storage device (94) to the second motor (40) for driving the second motor, and (b-2) supplying the electrical energy from the storage device (94) to the first motor (30) for driving the first motor.