DE69614754T2 - Drive arrangement and control method for auxiliary units of a hybrid vehicle - Google Patents

Description

Background of the invention Field of the invention

The present invention relates essentially to an energy output device and a method for controlling the same. More specifically, the invention relates to an energy output device for transmitting or using energy output from an internal combustion engine with high efficiency and a method for controlling such an energy output device.

Description of the related prior art

In proposed power transmission devices mounted on a vehicle, an output shaft of an internal combustion engine is electromagnetically connected to a drive shaft connected to a rotor of a motor via an electromagnetic clutch so that power of the internal combustion engine is transmitted to the drive shaft (as disclosed in, for example, Japanese Patent Laid-Open Gazette No. 53-133814). When the rotational speed of the engine that starts driving the vehicle reaches a predetermined level, the proposed power output device supplies an exciting current to the electromagnetic clutch to start the internal combustion engine, and then carries out fuel injection into the internal combustion engine and spark ignition, thereby starting the internal combustion engine and allowing the internal combustion engine to supply power. On the other hand, when the vehicle speed is reduced and the rotational speed of the engine decreases to the predetermined value or below, the power output device stops supplying the exciting current to the electromagnetic clutch. as well as fuel injection into the internal combustion engine and spark ignition, which terminates the operation of the internal combustion engine.

In the vehicle incorporating such a power output device, power required to drive an auxiliary device is obtained through the rotation of the output shaft of the engine or balanced with the electric energy stored in a battery. The auxiliary device includes auxiliary devices required for the operation of the power output device, such as a pump for circulating the cooling water of the engine, and those required not for the operation of the power output device but for the operation of the vehicle, such as a pump for power steering and a pump for air conditioning. In the system for supplying the power of the auxiliary device from the battery, it is necessary that the battery has a large capacity and is therefore large in order to supply sufficient electric energy to the auxiliary device. The battery is generally charged with the regenerative electric energy corresponding to the slip of the electromagnetic clutch. The overall energy efficiency is thus reduced depending on the operating efficiency of the electromagnetic clutch and the charging and discharging efficiency of the battery.

In the system in which the auxiliary equipment is mechanically connected to the output shaft of the internal combustion engine, mechanical energy generated by rotation of the output shaft is directly supplied as energy to the auxiliary equipment. In this structure, the above-mentioned problems are not generated. However, in this structure, the output shaft of the internal combustion engine does not rotate when the internal combustion engine stops its operation, and the vehicle is driven only by the electric energy stored in the battery. The stationary output shaft does not generate any energy required to operate the auxiliary system.

Document EP-A-0 510 582 relates to a vehicle drive machine with a thermal drive device (internal combustion engine) and an electrical drive device (electric motor). The internal combustion engine is connectable to a drive shaft via a first clutch. A drive selectively transfers energy from the drive shaft to a shaft on which auxiliary devices are installed. The electric motor is connectable to the drive shaft via a further clutch. The internal combustion engine drives the shaft and a generator via a drive. The generator can also be used as a motor; in this case the drive contains a further clutch. This vehicle drive machine has the disadvantage that the energy transferred from the electric motor to the wheels in the case of a very low speed may not be sufficient to drive the auxiliary device with sufficient energy. Furthermore, the efficiency of this vehicle drive machine is not very high because energy is consumed at the drives and the clutches. In addition, the present generator also generates energy in the case that all the energy from the internal combustion engine should preferably be used to drive only the drive shaft and the shaft.

Document US-A-3 699 351 discloses a vehicle with two modes of operation and two motors for driving an output shaft, an auxiliary generator and an oil pump, each motor having its own stator. Therefore, the two motors have two stators and two rotors. These motors can be coupled via a device which consumes a considerable amount of electrical or mechanical energy. Consequently, the efficiency in driving an auxiliary device is not very high.

The closest prior art document US 3 789 281 relates to a device in which the output shaft of a prime mover is connected to a rotor of an electromagnetic clutch. The other rotor of the electromagnetic clutch is provided on a drive shaft connected to a rotor of a rotating machine. Also in this case, the output shaft of the internal combustion engine does not rotate when the internal combustion engine stops its operation.

Summary of the invention

The object of the present invention, which overcomes the disadvantages of the prior art structures, is thus to transmit or use energy generated by an internal combustion engine with a high degree of efficiency and to enable sufficient energy to be supplied to an auxiliary system connected to an output shaft of the internal combustion engine even when the internal combustion engine stops operating and the vehicle is driven only by the electrical energy stored in a battery.

This object is achieved by energy delivery devices according to claims 1 and 5 and by methods according to claims 8 and 10.

A first energy output device according to the background of the invention 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 connected to one another, whereby between the output shaft of the internal combustion engine and the drive shaft via the electromagnetic connection of the first and second rotors, a drive circuit for the first motor and for controlling a degree of electromagnetic connection of the first rotor and the second rotor in the first motor for regulating the rotation of the second rotor with respect to the first rotor, a second motor connected to the drive shaft, a drive circuit for the second motor for driving and controlling the second motor, a storage battery charged with the electrical energy regenerated by the first motor via the drive circuit for the first motor, charged with the electrical energy regenerated by the second motor via the drive circuit for the second motor, discharging the electrical energy required to drive the first motor via the drive circuit for the first motor, and discharging the electrical energy required to drive the second motor via the drive circuit for the second motor, an auxiliary system connected to the output shaft of the internal combustion engine and driven by the energy of the output shaft, and an auxiliary system control device for controlling the drive circuit for the first motor to enable the first motor supplies a torque to the output shaft of the internal combustion engine using the electrical energy stored in the storage battery while the internal combustion engine stops operating, the torque enabling the output shaft of the internal combustion engine to rotate at a predetermined speed.

According to the background of the invention, even if the internal combustion engine stops operating, the first power output device can drive the first motor with the electric energy stored in the storage battery to rotate the output shaft of the internal combustion engine and thereby drive the auxiliary equipment that connects to the output shaft of the internal combustion engine.

According to an aspect of the first power output device according to the background of the invention, the torque is a first torque and the auxiliary equipment control means includes means for controlling the drive circuit for the second motor to enable the second motor to apply a second torque to the drive shaft to reduce a change in the torque of the drive shaft due to the rotation of the output shaft of the internal combustion engine at the predetermined speed.

According to a still further aspect of the first power output device according to the background of the invention, the auxiliary equipment control means comprises means for controlling the drive circuit for the second motor to enable the second motor to apply the second torque to the drive shaft as a sum of the third torque and a fourth torque, the third torque being applied to rotate the drive shaft and the fourth torque having a magnitude substantially equal to the first torque applied by the first motor to rotate the output shaft of the internal combustion engine at the predetermined torque but opposite to the first torque.

A second energy output device according to the background of the invention comprises: an internal combustion engine with an output shaft, a complex motor with a first rotor connected to the output shaft of the internal combustion engine, a second rotor connected to the drive shaft, which is arranged coaxially and rotatably with respect to the first rotor, and a stator for rotating the second rotor, wherein the first rotor and the second rotor form a first motor, the second rotor and the stator form a second motor, a drive circuit for the first motor for driving and controlling the first motor in the complex motor, a second motor drive circuit for driving and controlling the second motor in the complex motor, a storage battery charged with electric energy regenerated by the first motor via the first motor drive circuit, charged with electric energy regenerated by the second motor via the second motor drive circuit, discharging the electric energy required to drive the first motor via the first motor drive circuit, and discharging the electric energy required to drive the second motor via the second motor drive circuit, an auxiliary equipment connected to the output shaft of the internal combustion engine and driven by the energy of the output shaft, and an auxiliary equipment control device for controlling the first motor drive circuit to enable the first motor in the complex motor to apply torque to the output shaft of the internal combustion engine with the electric energy stored in the storage battery while the internal combustion engine stops operating, wherein the torque enables the output shaft of the internal combustion engine to rotate at a predetermined speed.

According to the background of the invention, even if the internal combustion engine stops operating, the second power output device can drive the first motor in the complex engine with the electric energy stored in the storage battery to rotate the output shaft of the internal combustion engine and thereby drive the auxiliary equipment that connects to the output shaft of the internal combustion engine. In the structure of the second power output device, the first motor is integrally connected to the second motor. This reduces the weight and size of the entire power output device.

According to an aspect of the second power output device according to the background of the invention, the torque is a first torque and the auxiliary equipment control means includes means for controlling the drive circuit for the second motor to enable the second motor in the complex engine to apply a second torque to the drive shaft to reduce a change in the torque of the drive shaft due to the rotation of the output shaft of the internal combustion engine at the predetermined speed.

According to an aspect of the second power output device according to the background of the invention, the auxiliary equipment control means controls the drive circuit for the second motor to enable the second motor in the complex engine to apply the second torque to the drive shaft as a sum of the third torque and a fourth torque, the third torque being applied to rotate the drive shaft and the fourth torque having a magnitude substantially equal to the first torque applied by the first motor in the complex engine to rotate the output shaft of the internal combustion engine at the predetermined speed but opposite to the first torque.

According to another aspect of the background of the invention, a third energy output device for outputting energy to a drive shaft 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 connected to one another, whereby between the output shaft of the internal combustion engine and the drive shaft via the electromagnetic connection of the first and second rotors energy is transmitted, a first motor drive circuit for controlling a degree of electromagnetic connection of the first rotor with the second rotor in the first motor and for regulating rotation of the second rotor with respect to the first rotor, a second motor having a third rotor connected to the output shaft of the internal combustion engine, a second motor drive circuit for driving and controlling the second motor, a storage battery charged with electrical energy regenerated by the first motor via the first motor drive circuit, charged with electrical energy regenerated by the second motor via the second motor drive circuit, discharging the electrical energy required to drive the first motor via the first motor drive circuit, and discharging the electrical energy required to drive the second motor via the second motor drive circuit, an auxiliary system connected to the output shaft of the internal combustion engine and driven by the energy of the output shaft, and an auxiliary system control device for controlling the second motor drive circuit Motor to enable the second motor to apply torque to the output shaft of the internal combustion engine with the energy stored in the storage battery while the internal combustion engine stops operating, the torque enabling the output shaft of the internal combustion engine to rotate at a predetermined speed.

According to the background of the invention, even if the internal combustion engine stops operating, the third power output device can drive the second motor with the electric energy stored in the storage battery to rotate the output shaft of the internal combustion engine and thereby drive the auxiliary equipment that connects to the output shaft of the internal combustion engine.

According to an aspect of the third power output device according to the background of the invention, the torque is a first torque, and the auxiliary equipment control device controls the drive circuit for the second motor to enable the second motor to apply the first torque, which is greater than a second torque applied to the drive shaft by the first motor, to the output shaft of the internal combustion engine.

According to yet another aspect of the background of the invention, a fourth power output device for outputting power to a drive shaft comprises: an internal combustion engine having an output shaft, a complex motor having a first rotor connected to the output shaft of the internal combustion engine, a second rotor connected to the drive shaft and arranged coaxially and rotatably with respect to the first rotor, and a stator for rotating the first rotor, the first rotor and the second rotor forming a first motor and the first rotor and the stator forming a second motor, a first motor drive circuit for driving and controlling the first motor in the complex motor, a second motor drive circuit for driving and controlling the second motor in the complex motor, a storage battery charged with electric energy regenerated by the first motor via the first motor drive circuit, charged with electric energy regenerated by the second motor via the second motor drive circuit, the electric energy required to drive the first motor via the first motor drive circuit and discharges the electrical energy required to drive the second motor through the second motor drive circuit, an auxiliary system connected to the output shaft of the internal combustion engine and powered by the energy of the output shaft and an auxiliary equipment control device for controlling the drive circuit for the second motor to enable the second motor in the complex motor to apply a torque to the output shaft of the internal combustion engine with the electric energy stored in the storage battery while the internal combustion engine stops its operation, the torque enabling the output shaft of the internal combustion engine to rotate at a predetermined speed.

According to the background of the invention, even if the internal combustion engine stops its operation, the fourth power output device can drive the second motor in the complex engine with the electric energy stored in the storage battery to rotate the output shaft of the internal combustion engine and thereby drive the auxiliary equipment that connects to the output shaft of the internal combustion engine. In the structure of the fourth power output device, the first motor is integrally connected to the second motor. This reduces the weight and size of the entire power output device.

According to an aspect of the fourth power output device according to the background of the invention, the torque is a first torque and the auxiliary equipment control means comprises means for controlling the drive circuit for the second motor to enable the second motor in the complex engine to apply the first torque, which is greater than a second torque applied to the drive shaft by the first motor in the complex engine, to the output shaft of the internal combustion engine.

The foregoing and other objects of the present invention are also achieved, at least in part, by a first method of controlling an energy delivery device to deliver energy to a drive shaft according to the background of the invention. The first method according to the background of the invention comprises the steps of: (a) providing an internal combustion engine having an output shaft, a first 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 arranged coaxially and rotatably with respect to the first rotor and the first and second rotors being electromagnetically connected to each other, whereby energy is transmitted between the output shaft of the internal combustion engine and the drive shaft via the electromagnetic connection of the first and second rotors, a second motor connected to the drive shaft, a storage battery charged with electrical energy regenerated by the first motor, charged with electrical energy regenerated by the second motor, discharging the electrical energy required to drive the first motor and discharging the electrical energy required to drive the second motor, and an auxiliary system connected to the output shaft of the internal combustion engine and driven by the energy of the output shaft and (b) controlling the first motor to enable the first motor to apply a torque to the output shaft of the internal combustion engine with the electrical energy stored in the storage battery while the internal combustion engine stops its operation, the torque enabling the output shaft of the internal combustion engine to rotate at a predetermined speed.

Even if the internal combustion engine stops operating, the first method according to the background of the invention can drive the first motor with the electric energy stored in the storage battery to rotate the output shaft of the internal combustion engine, and thereby drive the auxiliary system which connects to the output shaft of the combustion engine.

According to an aspect of the first method according to the background of the invention, the torque is a first torque and the first method further comprises the step (c) of controlling the second motor to enable the second motor to apply a second torque to the drive shaft as a sum of a third torque and a fourth torque, the third torque being applied to rotate the drive shaft and the fourth torque having a magnitude substantially equal to the first torque applied by the first motor to rotate the output shaft of the internal combustion engine at the predetermined speed but opposite to the first torque.

A second method according to the background of the invention comprises the steps of: (a) providing an internal combustion engine having an output shaft, a first 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 connected to each other, whereby energy is transmitted between the output shaft of the internal combustion engine and the drive shaft via the electromagnetic connection of the first and second rotors, a second motor connected to the output shaft of the internal combustion engine, a storage battery charged with electrical energy regenerated by the first motor, charged with electrical energy regenerated by the second motor, discharging the electrical energy required to drive the first motor and discharging the electrical energy required to drive the second motor, and an auxiliary system connected to the output shaft of the internal combustion engine and driven by the energy of the output shaft, and (b) controlling the second motor to enable the second motor to apply a torque to the output shaft of the internal combustion engine with the electrical energy stored in the storage battery while the internal combustion engine stops its operation, the torque enabling the output shaft of the internal combustion engine to rotate at a predetermined speed.

Even if the internal combustion engine stops its operation, the second method according to the background of the invention can drive the second motor with the electric energy stored in the storage battery to rotate the output shaft of the internal combustion engine and thereby drive the auxiliary equipment that connects to the output shaft of the internal combustion engine.

According to an aspect of the second method according to the background of the invention, the torque is a first torque and the second method further comprises the step (c) of controlling the drive circuit for the second motor to enable the second motor to apply the first torque, which is greater than a second torque applied to the drive shaft by the first motor, to the output shaft of the internal combustion engine.

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

Short description of the drawings

Fig. 1 schematically illustrates the 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 40 included in the power output device 20 of Fig. 1,

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

Fig. 4 is a diagram showing the operation principle of the energy output device 20,

Fig. 5 is a flowchart showing a torque control routine executed by the controller 80 in the first embodiment,

Fig. 6 is a flowchart showing details of the control process of the clutch motor 30 executed in step S108 in the flowchart of Fig. 5,

Figs. 7 and 8 are flowcharts showing details of the control process of the assist motor 40 executed in step S110 in the flowchart of Fig. 5,

Fig. 9 is a flowchart showing an engine stop time torque control routine executed by the controller 80 in the first embodiment,

Fig. 10 schematically shows an energy output device 20A as a modification of the first embodiment,

Fig. 11 schematically illustrates a structure of another energy output device 20B as a second embodiment according to the present invention,

Fig. 12 is a flowchart showing a torque control routine executed by the controller 80 in the second embodiment,

Fig. 13 is a flowchart showing an engine stop time torque control routine executed by the controller 80 in the second embodiment,

Fig. 14 schematically illustrates an energy output device 20C as a modification of the second embodiment, and

Fig. 15 schematically illustrates an energy delivery device 20D as a further modification of the second embodiment.

Description of the preferred embodiment

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; Fig. 3 is a schematic view showing a general structure of a vehicle incorporating the power output device 20 of Fig. 1. The general structure of the vehicle will be described first for convenience.

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

The operation of the internal combustion engine 50 is controlled by an electronic control unit (hereinafter referred to as EFIECU) 70. The EFIECU 70 receives information from numerous sensors that detect the operating conditions of the internal combustion engine 50. These sensors include a throttle valve position sensor 67 for detecting the position of the throttle valve 66, a manifold vacuum sensor 72 for measuring a load applied to the internal combustion engine 50, a water temperature sensor 74 for measuring the temperature of the cooling water in the internal combustion engine 50, and a speed sensor 76 and an angle sensor 78 mounted on the distributor 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 switch (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 internal combustion engine 50 is connected to a drive shaft 22 via a clutch motor 30 and an auxiliary motor 40 (which will be described in detail later). The drive shaft 22 is further connected to a differential gear 24, which then Drive shaft 22 of power output device 20 transmits torque output to left and right driving wheels 26 and 28. The clutch motor 30 and the assist motor 40 are driven and controlled by a controller 80. The controller 80 has an internal control CPU and receives input signals from a gear shift position sensor 84 attached to a gear shift device 82 and an accelerator pedal position sensor 65 attached to an accelerator pedal 64, as will be described in detail later. The controller 80 sends a variety of data and information to and receives from the EFIECU 70 by communication. Details of the control procedure including a communication protocol will be described later.

Some auxiliary systems are connected directly or through a belt 102 to a crankshaft 56B that projects from the engine 50 opposite to the crankshaft 56. The auxiliary systems include a cooling pump 104 for circulating cooling water for the engine 50 and a P/S pump 106 for supplying power to a power steering system. These auxiliary systems receive power generated by rotation of the crankshaft 56B.

Referring to Fig. 1, the energy output device 20 essentially comprises the internal combustion engine 50, 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 internal combustion engine 50, whereas 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 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 mounted on the distributor 60.

The auxiliary motor 40 is also constructed as a synchronous motor with three-phase coils 44 wound on a stator 43 that is attached 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 attached 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 power output device 20. A resolver 48 for measuring a rotation angle θd 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 the axial torque of the crankshaft 56 of the internal combustion engine 50 are transmitted via the outer rotor 32 to the inner rotor 34 of the clutch motor 30, the rotation and torque are added or subtracted from the transmitted rotation and torque by the auxiliary motor 40.

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 having the permanent magnets 35 and the inner rotor 34 having the three-phase coils 36. The detailed structure of the clutch motor 30 will be described by means of the cross-sectional view of Fig. 2. The outer rotor 32 of the clutch motor is fixed to a peripheral end portion of a wheel 57 arranged around the crankshaft 56 by means of a push pin 59a and a screw 59b. A central portion of the wheel 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 attached to the inner rotor 34.

A plurality of permanent magnets 35, four in this embodiment, are fixed to the inner surface of the outer rotor 32 as described above. The permanent magnets 35 are magnetized in the direction toward the axial center of the clutch motor 30 and have magnetic poles with alternating 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 that pass through the teeth (not shown) separating the slots from each other. 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 electrical energy supplied from the rotary converter 38. The rotary converter 38 has primary windings 38a secured to the housing 45 and secondary windings 38b secured to the drive shaft 22 coupled to the inner rotor 34. Electromagnetic induction enables electrical energy to be transferred from the primary windings 38a to the secondary windings 38b or vice versa. The rotary converter 38 has windings for three phases, ie, for a U, V and W phase, to enable the transfer of the 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 are described below based on the flow charts.

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 one-chip microprocessor having a RAM 90a used as a working memory, a ROM 90b, in which numerous 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 internal combustion engine from the resolver 39, a rotation angle θd of the drive shaft 22 from the resolver 48, an accelerator pedal position AP (depression amount of the accelerator pedal 64) from the accelerator pedal position sensor 65, a gear shift position SP from the gear shift 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 meter 99. The remaining capacity meter 99 can determine the remaining capacity BRM of the battery 94 by any known method, for example, B. 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 the charging and discharging time, or by causing a sudden 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 the six transistors Tr1 to Tr6 operating as switching elements of the first drive circuit 91 and a second control signal SW2 for driving the 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 via the Rotary converter 38 is connected to the respective contacts of the paired transistors. Power lines P1 and P2 are connected to the plus and minus terminals of the battery 94, respectively. The first control signal SW1 output from the control CPU 90 sequentially controls the turn-on time of the paired transistors Tr1 to Tr6. The current flowing through each coil 36 is subjected to PWM (Pulse Width Modulation) to obtain a quasi-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 form 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 turn-on times 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 energy output device 20 constructed in this way operates according to the working principles described below, in particular the principle of torque conversion. For example, it is assumed that the internal combustion engine 50 driven by the EFIECU 70 rotates at a speed Ne equal to a predetermined value N1. While the transistors Tr1 to Tr6 in the first drive circuit 91 are in the off position, the control device 80 does not supply current to the three-phase coils 36 of the clutch motor 30 via the rotary converter 38. The lack of supply of electrical Current causes the outer rotor 32 of the clutch motor 30 to be electromagnetically separated from the inner rotor 34. This results in the crankshaft 56 of the internal combustion engine 50 spinning. Under the condition that all transistors Tr1 to Tr6 are in the off position, no regeneration of energy from the three-phase coils 36 occurs; the internal combustion engine 50 is kept idling.

When the control CPU 90 of the controller 80 outputs the first control signal SW1 to control the transistors Tr1 to Tr6 in the first drive circuit 91 on and off, a constant electric current flows through the three-phase coils 36 of the clutch motor 30 based on the difference between the rotational speed Ne of the crankshaft 56 of the engine 50 and a rotational speed Nd of the drive shaft 22 (i.e., the difference Nc (= Ne-Nd) between the rotational speed of the outer rotor 32 and that of the inner rotor 34 in the clutch motor 34). Accordingly, a certain slip occurs between the outer rotor 32 and the inner rotor 34, which are connected to each other in the clutch motor 30. At this time, the inner rotor 34 rotates at the rotational speed Nd which is lower than the rotational speed Ne of the crankshaft 56 of the engine 50. In this state, the clutch motor 30 functions as a generator and performs the regenerative operation to regenerate an electric current via the first drive circuit 91. In order to allow the auxiliary motor 40 to consume energy identical to the energy regenerated by the clutch motor 30, the control CPU 90 controls the transistors Tr11 to T16 in the second drive circuit 92 on and off. The on and off control of the transistors Tr11 to Tr16 allows an electric current to flow through the three-phase coils 44 of the auxiliary motor; the auxiliary motor 40 thus performs the energy operation to generate torque.

Referring to Fig. 4, while the crankshaft 56 of the engine is driven at a speed N1 and a torque T1, energy in a range G1 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 G2 that allows the drive shaft 22 to rotate at a speed N2 and a torque T2. The torque conversion is carried out in the manner discussed above; energy corresponding to the slip in the engine 30 or the speed difference Nc (= Ne-Nd) is thus output as a torque to the drive shaft 22.

In another example, it is assumed that the internal combustion engine 50 is driven at a speed Ne=N2 and a torque Te=T2 while the drive shaft 22 rotates at the speed N1 which is greater than the speed N2. In this state, the inner rotor 34 of the clutch motor 30 rotates with respect to the outer rotor 32 in the direction of rotation of the drive shaft 22 at a speed defined by the absolute value of the speed difference Nc (= Ne-Nd). While the clutch motor 30 operates as a normal motor, it consumes electrical energy to apply the energy of the rotational motion to the drive shaft 22. When the control CPU 90 of the controller 80 controls the second drive circuit 92 to allow the auxiliary motor to regenerate electric energy, slip between the rotor 42 and the stator 43 of the auxiliary motor 40 causes the regenerative current to flow through the three-phase coils 44. To allow the clutch motor 30 to consume the energy regenerated by the auxiliary motor 40, the control CPU 90 controls both the first drive circuit 91 and the second drive circuit 92. This allows the clutch motor 30 to be driven without using electric energy stored in the battery 94.

Referring again to Fig. 4, when the crankshaft 56 of the internal combustion engine 50 is driven at the speed N2 and the torque T2, energy in the sum of the areas G2 and G3 is regenerated as electrical energy by the auxiliary motor 40 and supplied to the clutch motor 30. The supply of the regenerated energy enables the drive shaft 22 to rotate at the speed N1 and the torque T1.

Unlike the torque conversion and the speed conversion explained above, the power output device 20 of the embodiment can charge the battery 95 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 engine 50 (i.e., the product of the torque Te and the speed Ne), the electric energy regenerated or consumed by the clutch motor 30, and the electric energy regenerated or consumed by the assist motor 40. The output energy from the engine 50 can thus be transmitted as power to the drive shaft 22 with a higher efficiency.

The torque conversion explained above is implemented according to the torque control process shown in the flow chart of Fig. 5. Next, the main torque control process carried out in the power output device 20 and then the similar process in the non-operating state of the internal combustion engine 50 will be described.

When the program enters the torque control routine, the control CPU 90 of the controller 80 first takes data of the rotational speed Nd of the drive shaft in step S100 22. The rotational speed Nd of the drive shaft 22 can be calculated from the rotation angle θd of the drive shaft 22 read from the resolver 48. In the subsequent step S101, the control CPU 90 reads the accelerator pedal position AP output from the accelerator pedal position sensor 65. The driver depresses the accelerator pedal 64 when he feels insufficient output torque. The value of the accelerator pedal position AP accordingly represents the desired output torque (ie, the desired torque of the drive shaft 22) required by the driver. The program then proceeds to step S102, in which the control CPU 90 calculates a target output torque Td* (of the drive shaft 22) corresponding to the inputted accelerator pedal position AP. The target output torque Td* is also referred to as the output torque setpoint. The output torque control values Td* were previously set for the respective accelerator pedal positions AP. In response to the input of the accelerator pedal position AP, the output torque control value Td* corresponding to the entered accelerator pedal position AP is extracted from the preset output torque control values Td*.

In step S103, an amount of energy Pd to be output to the drive shaft 22 is calculated according to the expression Pd = Td*xNd, that is, by multiplying the extracted output torque set value Td* (of the drive shaft 22) by the input rotation speed Nd of the drive shaft 22. The program then goes to step S104, in which the control CPU 90 sets a target engine torque Te* and a target engine rotation speed Ne* of the engine 50 based on the output energy Pd thus obtained. Here, it is assumed that all of the energy Pd to be output to the drive shaft 22 is supplied by the engine 50. Since the mechanical energy supplied from the engine 50 is equal to the product of the torque Te and the rotation speed Ne of the engine 50, the relationship between the output power Pd, 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 the operation of the engine 50 with the highest possible efficiency.

In the subsequent step S106, 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 S104. In order to keep the rotation speed Ne of the engine 50 at a substantially constant level, the torque of the clutch motor 30 is required to balance the torque of the engine 50. The processing in step S106 accordingly sets the torque set value Tc* of the clutch motor 30 equal to the target engine torque Te*.

After setting the torque control value Tc* of the clutch motor 30 in step S106, the program goes to steps S108, S110 and S111 to control the clutch motor 30, the auxiliary motor 40 and the engine 50, respectively. For the sake of convenience of illustration, the control operations of the clutch motor 30, the auxiliary motor 40 and the engine 50 are shown as separate steps. However, in actual processing, these control operations are comprehensively carried out. For example, the control CPU 90 simultaneously controls the clutch motor 30 and the auxiliary motor 40 by interrupt processing while sending a command to the EFIECU 70 by communication to simultaneously control the combustion engine 50.

Fig. 6 is a flowchart showing details of the control process of the clutch motor 30 executed in step S108 in the flowchart of Fig. 5. 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 engine 50 from the resolver 39 in step S114. 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 then proceeds to step S118, where the control CPU 90 receives inputs from the ammeters 95 and 96 of the clutch motor currents Iuc and Ivc flowing through the U-phase and the V-phase of the three-phase coils 36 in the clutch motor 30, respectively. Although the currents naturally flow through all three phases U, V, and W, measurement is only required for the currents flowing through the two phases since the sum of the currents is zero. In the subsequent step S120, the control CPU 90 performs coordinate conversion (a conversion from three phases to two phases) using the values of the currents flowing through the three phases obtained in step S118. In the coordinate conversion, the values of the currents flowing through the three phases are mapped against the values of the currents passing through the d- and q-axes of the permanent magnet synchronous motor; the coordinate conversion 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 type synchronous motor. Alternatively, the torque control can be performed directly using the currents flowing through the three phases.

After converting the currents of two axes, the control CPU 90 calculates deviations of the currents Idc and Iqc actually flowing through the d- and q-axes from the current set values Idc* and Iqc* of the respective axes calculated from the torque set value Tc* of the clutch motor 30, and determines the voltage set values Vdc and Vqc for the d- and q-axes in step S122. According to a concrete procedure, the control CPU 90 performs operations according to the following equations (2) and (3):

ΔIdc = Idc* - Idc ΔIqc = Iqc* - Iqc ... (2)

Vdc = Kp1·ΔIdc + ΔKil Mdc Vqc = Kp2 - ΔIqc + ΔKi2 - ΔIqc ... (3)

where Kp1, Kp2, Ki1 and Ki2 represent coefficients that are adjusted to suit the characteristics of the motor used. The voltage control value Vdc (Vqc) has a part proportional to the deviation ΔI from the actual control value I* (first term on the right-hand side in 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 converts the coordinates of the voltage control values thus obtained back in step S124 (Conversion from two phases to three phases). This corresponds to a reversal of the conversion performed in step S120. The reconversion determines voltages Vuc, Vvc and Vwc that are actually applied to the three-phase coils 36, as described below:

The actual voltage control of the real voltage is performed by the on-off operation of the transistors Tr1 to Tr6 in the first drive circuit 91. In step S126, the on and off time of the transistors Tr1 to Tr6 in the first drive circuit 91 is controlled by PWM (Pulse Width Modulation) to obtain the voltage control values Vuc, Vwc and Vwc determined in the above equation (4).

The torque set value Tc* is positive when a positive torque is applied to the drive shaft 22 in the rotation direction of the crankshaft 56. For example, it is assumed that the torque set value Tc* is set to a positive value. When the rotation speed Ne of the engine 50 is greater than the rotation speed Nd of the drive shaft 22 in this assumption, that is, when the rotation speed difference Nc (= Ne-Nd) is positive, the clutch motor 30 is controlled to perform the regenerative operation and generate a regenerative current corresponding to the rotation speed difference Nc. In contrast, when the rotation speed Ne of the engine 50 is smaller than the rotation speed Nd of the drive shaft 22, that is, when the rotation speed difference Nc (= Ne-Nd) is negative, the clutch motor 30 is controlled to perform the power operation and rotate with respect to the crankshaft 56 in the rotation direction of the drive shaft 22 at a speed determined by the absolute value the speed difference Nc. For the positive torque command value Tc*, both the regenerative operation and the power operation of the clutch motor 30 implement the identical switching control. According to a concrete procedure, the transistors Tr1 to Tr6 of the first drive circuit 91 are controlled to allow a positive torque to be applied to the drive shaft 22 by the combination of the magnetic field generated by the permanent magnets 35 arranged on the outer rotor 32 with the rotating magnetic field generated by the currents flowing through the three-phase coils 36 on the inner rotor 34 in the clutch motor 30. The identical switching control is carried out for both the regenerative operation and the power operation of the clutch motor 30 as long as the sign of the torque command value Tc* is not changed. The clutch motor control routine of Fig. 6 is thus applicable to both the regenerative operation and the power operation. When the drive shaft 22 is braked or the vehicle is moving backward, the torque command value Tc* has the negative sign. The clutch motor control routine of Fig. 6 is also applicable to the control procedure under such conditions when the relative angle θc changes in the reverse direction in step ST26.

7 and 8 are flowcharts showing details of the control process of the auxiliary motor 40 executed in step S110 in the flowchart of Fig. 5. Referring to the flowchart of Fig. 7, when the program enters the auxiliary motor control routine, the control CPU 90 first takes in data of the rotational speed Nd of the drive shaft 22 in step S131. The rotational speed Nd of the drive shaft 22 is calculated from the rotational angle θd of the drive shaft 22 read from the resolver 48. The control CPU 90 then takes in data of the rotational speed Ne of the engine 50 in step S132. The rotational speed Ne of the engine 50 can be calculated from the rotational angle θe of the crankshaft 56, the read by the resolver 39, or directly measured by the speed sensor 76 mounted on the distributor 60. In the latter case, the control CPU 90 receives data on the speed Ne of the internal combustion engine 50 by communicating with the EFIECU 70, which establishes a connection with the speed sensor 76.

A speed difference Nc between the input speed Nd of the drive shaft 22 and the input speed Ne of the engine 50 is calculated according to the equation Nc = Ne-Nd in step S133. In the following step S134, the electric power (energy) Pc regenerated or consumed by the clutch motor 30 is calculated according to the following equation (5):

Pc = Ksc · Nc · Tc (5)

where Ksc represents the efficiency of the regenerative operation or the energy operation in the clutch motor 30. The product NcxTc defines the energy corresponding to the area G1 in the graph of Fig. 4, where Nc and Tc denote the speed difference and the actual torque generated by the clutch motor 30.

In step S135, a torque control value Ta* of the auxiliary motor 40 is determined by the following equation (6):

Ta* = ksa · Pc/Nd (6)

where ksa represents the efficiency of the regenerative operation or the energy operation in the auxiliary motor 40. The torque control value Ta* of the auxiliary motor 40 thus obtained is compared in step S136 with a maximum torque Tamax that the auxiliary motor 40 can potentially assume. If the torque control value Ta* exceeds the maximum torque Tamax, the program goes to step S138, in which the torque control value Ta* is limited to the maximum torque Tamax.

After the torque set value Ta* is set equal to the maximum torque Tamax in step S138 or after the torque set value Ta* is determined not to exceed the maximum torque Tamax in step S136, the program proceeds to step S140 in the flow chart of Fig. 8. The control CPU reads the rotation angle θd of the drive shaft 22 from the resolver 48 in step S140 and receives data of the auxiliary motor currents Iua and Iva flowing through the U-phase and 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 coordinate conversion for the currents of the three phases in step S144, calculates the voltage set values Vda and Vga in step S146, and carries out inverse coordinate conversion 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 carried out 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 flowchart of Fig. 6.

The auxiliary motor 40 is subjected to the power operation for the positive torque setpoint Ta* and the regenerative operation for the negative torque setpoint Ta*. As with the power operation and regenerative operation of the clutch motor 30, the auxiliary motor control routine of Figs. 7 and 8 is applicable to both the power operation and the regenerative operation of the auxiliary motor 40. This also applies when the drive shaft 22 rotates opposite to the crankshaft 56, ie when the vehicle moves backwards. The torque setting value Ta* of the auxiliary motor 40 is positive when a positive torque is applied to the drive shaft 22 in the direction of rotation of the crankshaft 56.

The control of the engine 50 (step S111 in Fig. 5) is carried out in the following manner: In order to achieve a steady drive with the target engine torque Te* and the target engine speed Ne* (which were set in step S104 in Fig. 5), the control CPU 90 regulates the torque Te and the speed Ne of the engine 50 to approximate 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 engine 50 to subsequently approach the target engine torque Te* and the target engine speed Ne*.

This procedure enables the output (TexNe) of the internal combustion engine 50 to undergo a free torque conversion and then be transmitted to the drive shaft 22.

The charge control of the battery 94 starts when the remaining capacity BRM of the battery 94 becomes equal to or smaller than a charge start value BL previously set as a value at which the charging process is required. The charging energy Pbi required to charge the battery 94 is added to the output energy Pd calculated in step S103 of the torque control routine of Fig. 5. The processing in step S104 and the subsequent steps is carried out with the newly set output energy Pd. On the other hand, the Charging energy Pbi is subtracted from the energy Pc of the clutch motor 30 calculated in step S134 of the assist motor control routine of Fig. 7. The processing in step S135 and subsequent steps is carried out with the newly set clutch motor energy Pc. This procedure allows the battery 94 to be charged with the charging energy Pbi.

On the other hand, the discharge control of the battery 94 starts when the remaining capacity BRM of the battery 94 becomes equal to or greater than a discharge start value BH previously set as a value at which the discharge process is required. A discharge energy Pbo required to discharge the battery 94 is subtracted from the output energy Pd calculated in step S103 of the torque control routine of Fig. 5. The processing in step S104 and subsequent steps is carried out with the newly set output energy Pd. On the other hand, the discharge energy Pbo is added to the energy Pc of the clutch motor 30 calculated in step S134 of the auxiliary motor control routine of Fig. 7. The processing in step S135 and subsequent steps is carried out with the newly set clutch motor energy Pc. This procedure allows the battery 94 to be discharged with the discharge energy Pbo.

In the power output device of the embodiment, when the battery 94 has a sufficient remaining capacity BRM, the vehicle can be driven only with the electric power supplied from the battery 94 while the engine 50 stops its operation. In this state, the engine stop time torque control routine shown in the flowchart of Fig. 9 is executed to implement the torque control only with the electric power supplied from the battery 94.

When the program enters the engine stop time torque control routine, the control CPU 90 of the controller 80 first acquires data of the accelerator pedal position AP from the accelerator pedal position sensor 65 in step S160 and calculates the output torque command value Td* corresponding to the input accelerator pedal position AP in step S162. The torque command value Tc* of the clutch motor 30 is set equal to a rotational torque TST in step S164. The rotational torque TST is a torque required to rotate the crankshaft 56 of the engine 50 at a predetermined speed while the engine 50 stops its operation. By setting the torque set value Tc* of the clutch motor 30 equal to the rotational torque TST, the auxiliary machines are enabled to be driven even when the engine 50 is stopped. The rotational torque TST, which corresponds to the predetermined rotational speed of the crankshaft 56, changes depending on the characteristics of the engine 50 and the power required to drive the auxiliary machines, such as the cooling pump 104 and the P/S pump 106, which are connected to the crankshaft 56B directly or via the belt 102. In the embodiment, in order to minimize the power consumed by the engine 50, the intake valve and the exhaust valve of the engine are kept in the closed position to stop the intake and exhaust in this torque control routine. This allows the compression energy to be balanced by the expansion energy.

In step S166, the torque control value Ta* of the auxiliary motor 40 is calculated according to the following equation (7):

Ta* = Td* + TST (7)

The torque control value Ta* thus obtained is compared in step S168 with the maximum torque Tamax that the auxiliary motor 40 can potentially apply. If the torque control value Ta* exceeds the maximum torque Tamax, the program goes to step S170 where the torque control value Ta* is limited to the maximum torque Tamax.

The control CPU 90 then controls the clutch motor 30 in step S172, the auxiliary motor 40 in step S174, and the engine 50 in step S176 based on the torque command values set as described above. The concrete procedure of the clutch motor control (step S172) is identical to that described above in accordance with the flow chart of Fig. 6. The torque of rotation TST set as the torque command value Tc* in step S164 in the engine stop time torque control routine of Fig. 9 acts in the opposite direction to the torque command value Tc* set in the process of the substantial torque control for transmitting the output from the engine 50 to the drive shaft 22, and thereby has a negative sign. This means that the voltage setpoints are calculated from the negative torque setpoint Tc* in the clutch motor control routine of Fig. 6.

The concrete procedure of the auxiliary motor control (step S174) is similar to the processing of steps S140 to S150 in the auxiliary motor control routine of Figs. 7 and 8, which is carried out in the process of the substantial torque control. This is because the torque set value Ta* of the auxiliary motor 40 has already been set by the processing of steps S166 to S170 in the engine stop time torque control routine of Fig. 9.

The engine controller (step S176) maintains the non-operating state of the engine 50 and keeps the intake valve and the exhaust valve of the engine 50 in the closed position regardless of the rotation of the crankshaft 56 as described above.

The power output device 20 of the embodiment can rotate the crankshaft 56 even when the engine 50 is stopped, and thereby drive the auxiliary equipment connected to the crankshaft 56B, such as the cooling pump 104 and the P/S pump 106. The torque command Ta* of the auxiliary motor 40 is set equal to the sum of the output torque command Td* and the rotational torque TST required to rotate the crankshaft 56 at the predetermined speed. Accordingly, the driver does not feel a reduction in torque due to the rotation of the crankshaft 56, but receives the torque corresponding to the amount of operation of the accelerator pedal 64. While the internal combustion engine 50 stops its operation, the intake valve and the exhaust valve of the internal combustion engine 50 are closed to minimize the energy consumption in the internal combustion engine 50.

In the power output device 20 of the embodiment, the torque control value Ta* of the auxiliary motor 40 is set equal to the sum of the output torque control value Td* and the rotational torque TST in the state in which the engine 50 is stopped. However, according to other applications, the torque control value Ta* of the auxiliary motor 40 may be set equal to the output torque control value Td* or the sum of the output torque control value Td* and another torque that is different from the rotational torque TST.

In the power output device 20 of the embodiment, the intake valve and the exhaust valve of the engine 50 are closed in the torque control process in the engine stop state. However, according to other applications, both the intake valve and the exhaust valve may be kept in an open position or may be opened or closed according to the rotation of the crankshaft 56. In the former alternative structure, neither compression nor expansion is carried out; thus, the pulsation of the torque is effectively reduced.

In the structure of the power output device 20 shown in Fig. 1, the clutch motor 30 and the auxiliary motor 40 are separately fixed to different positions of the drive shaft 22. However, as in a modified power output device 20A shown in Fig. 10, 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 34A that connects to the crankshaft 56 and an outer rotor 32A that connects to the drive shaft 22. Three-phase coils 36A are fixed to the inner rotor 34A; permanent magnets 35A are arranged on the outer rotor 32A in such a manner that the outer surface and the inner surface thereof have different magnetic poles. An auxiliary motor 40A includes 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 36A are fixed to the inner rotor 34A which connects to the crankshaft 56, a rotary converter 38A for supplying electric power to the three-phase coils 36A 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 36A on the inner rotor 34A is controlled with respect to the inner surface magnetic pole of the permanent magnets 35A arranged on the outer rotor 32A. This allows 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 allows the auxiliary motor 40A to operate in the same manner as the auxiliary motor 40 of the power output device 20. The torque control routine of Fig. 5 and the energy stopping time torque control routine of Fig. 9 are also applicable to the energy output device 20A shown in Fig. 10, which accordingly implements the same operations and has the same effects as those of the energy output device 20 shown in Fig. 1.

As described above, the outer rotor 32A functions simultaneously 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 power output device 20A.

Fig. 11 schematically shows an essential portion of another power output device 20B as a second embodiment of the present invention. The power output device 20B of Fig. 11 has a similar structure to the power output device 20 of Fig. 1, except that the auxiliary motor 40 is attached to the crankshaft 56 located between the internal combustion engine 50 and the clutch motor 30. In the power output device 20B of the second embodiment, similar numerals and symbols denote similar elements to those in the power output device 20 of Fig. 1. The symbols, used in the description have similar meanings unless otherwise stated.

The following describes the essential operation of the power output device 20B shown in Fig. 11. For example, assume that the internal combustion engine 50 is driven with a torque Te and a rotational speed Ne. When a torque Ta is added to the crankshaft 56 by the auxiliary motor 40 connected to the crankshaft 56, the crankshaft 56 is consequently acted upon by the sum of the torques (Te+Ta). When the clutch motor 30 is controlled to generate the torque Tc equal to the sum of the torques (Te+Ta), the torque Tc (= Te+Ta) is transmitted to the drive shaft 22.

When the rotational speed Ne of the engine 50 is greater than the rotational speed Nd of the drive shaft 22, the clutch motor 30 regenerates electric energy based on the rotational speed difference Nc between the rotational speed Ne of the engine 50 and the rotational speed Nd of the drive shaft 22. The regenerated energy is supplied to the auxiliary motor 40 via the power lines P1 and P2 and the second drive circuit 92 to activate the auxiliary motor 40. Provided that the torque Ta of the auxiliary motor 40 is substantially equivalent to the electric energy regenerated by the clutch motor 30, free torque conversion is permitted for the energy output from the engine 50 within a range satisfying the relationship of the following equation (8). Since the relationship of equation (8) represents the ideal state with an efficiency of 100%, (Tc · Nd) is a little smaller than (Te · Nd) in the actual state.

Te · Ne = Tc · Nd (8)

Referring to Fig. 4, under the condition that the crankshaft 56 rotates at the torque T1 and at the speed N1, the energy corresponding to the sum of the areas G1+G3 is regenerated by the clutch motor 30 and supplied to the auxiliary motor 40. The auxiliary motor 40 converts the absorbed energy in the sum of the areas G1+G3 into the energy corresponding to the sum of the areas G2+G3, and transmits the converted energy to the crankshaft 56.

When the rotation speed Ne of the engine 50 is smaller than the rotation speed Nd of the drive shaft 22, the clutch motor 30 operates as a normal motor. In the clutch motor 30, the inner rotor 34 rotates with respect to the outer rotor 32 in the rotation direction of the drive shaft 22 at a rotation speed defined by the absolute value of the rotation speed difference Nc (= Ne-Nd). Provided that the torque Ta of the auxiliary motor 40 is set to a negative value, which allows the auxiliary motor 40 to regenerate electric energy substantially equivalent to the electric energy consumed by the clutch motor 30, free torque conversion for the energy output from the engine 50 is also permitted within the range satisfying the relationship of the above equation (8).

Referring to Fig. 4, under the condition that the crankshaft 56 rotates at the torque T2 and the speed N2, the energy corresponding to the area G2 is regenerated by the assist motor 40 and consumed by the clutch motor 30 as the energy corresponding to the area G1.

The control procedure of the second embodiment explained above follows the torque control routine shown in the flow chart of Fig. 12. When the program enters the torque control routine, the control CPU 90 executes the control device 80 first executes the processing of steps S200 to S208, which is identical to that of steps S100 to S104 in the flowchart of Fig. 5. The control CPU 90 reads the rotational speed Nd of the drive shaft 22 in step S200 and the accelerator pedal position AP in step S202, and calculates the output torque set value Td* from the input accelerator pedal position AP in step S204. The control CPU 90 then calculates the energy Pd to be output from the drive shaft 22 in step S206 based on the calculated output torque set value Td* and the input rotational speed Nd of the drive shaft 22, and sets the target engine torque Te* and the target engine speed Ne* of the engine 50 in step S208.

In the following step S210, the control CPU 90 calculates the torque setting value Ta* of the auxiliary motor 40 according to the following equation (9):

Ta* = Ksc · (Td* - Te*) (9)

In step S212, the torque control value Tc* of the clutch motor 30 is calculated from the thus obtained torque control value Ta* of the assist motor 40 according to the equation (10) which is as follows:

Tc* - Te* + Ta* (10)

The control CPU 90 controls the clutch motor 30 in step S214, the auxiliary motor 40 in step S216 and the engine 50 in step S217 based on the torque command values Ta* and Tc*, the target engine torque Te* and the target engine speed Ne* thus obtained. The concrete procedure of the clutch motor control (step S214) is identical to that described above according to the flow chart of Fig. 6, whereas the concrete procedure of the Engine control (step S217) is identical to that of the first embodiment explained above. The auxiliary motor control executed in step S216 follows substantially the processings of steps S140 to S150 in the auxiliary motor control routine of Fig. 8 except that the rotation angle θe of the crankshaft 56 of the engine 50 measured by the resolver 39 is processed instead of the rotation angle θd of the drive shaft 22. This modification is attributed to the position of the auxiliary motor 40 attached to the crankshaft 56.

As with the power output device 20 of the first embodiment, the battery 94 can be charged and discharged according to the requirements in the power output device 20B of the second embodiment. The vehicle can be driven only with the electric power stored in the battery 94 while the engine 50 stops its operation. Fig. 13 is a flowchart showing an engine stop time torque control routine executed in the second embodiment.

When the program enters the engine stop time torque control routine, the control CPU 80 first acquires accelerator pedal position AP data from the accelerator pedal position sensor 65 in step S220 and calculates the output torque set value Td* corresponding to the input accelerator pedal position AP in step S222. The torque set value Ta* of the auxiliary motor 40 is set equal to the sum of the output torque set value Td* and the rotational motion torque TST in step S224. The torque set value Ta* thus obtained is compared with the maximum torque Tamax that the auxiliary motor 40 can potentially apply in step S226. If the torque set value Ta* exceeds the maximum torque Tamax, the program goes to step S228 in which the torque control value Ta* is limited to the maximum torque Tamax. The torque control value Tc* of the clutch motor 30 is then determined by subtracting the torque of the rotational movement TST from the torque control value Ta* of the auxiliary motor 40. If the torque control value Ta* of the auxiliary motor 40 does not exceed the maximum torque Tamax in step S226, the torque control value Tc* of the clutch motor 30 is set equal to the output torque control value Td*.

The control CPU 90 then controls the clutch motor 30 in step S232, the auxiliary motor 40 in step S234 and the engine 50 in step S236 based on the torque control values set as described above. The concrete procedures of the clutch motor control (step S232), the auxiliary motor control (step S234) and the engine control (step S236) are identical to those of steps S172, S174 and S176 in the engine stop time torque control routine of Fig. 9, except that the rotation angle θe of the crankshaft 56 of the engine 50 is processed in the auxiliary motor control instead of the rotation angle θd of the drive shaft 22.

In the structure of the second embodiment, a torque difference corresponding to the rotational torque TST is set between the torque set value Tc* of the clutch motor 30 and the torque set value Ta* of the auxiliary motor 40. This increases the rotational speed of the crankshaft 56 of the internal combustion engine 50 under the condition that the internal combustion engine 50 stops its operation. As described above, the auxiliary equipment such as the cooling pump 104 and the P/S pump 106 are directly connected to the crankshaft 56B via the belt 102. The crankshaft 56 accordingly rotates at a speed that causes the energy corresponding to the rotational torque TST to be equal to the sum of the Energy consumed by the piston-like movement of the internal combustion engine 50 and the energy consumed by the operation of the auxiliary systems.

The power output device 20B of the second embodiment can rotate the crankshaft 56 even when the engine 50 is stopped, and thereby drive the auxiliary machines connected to the crankshaft 56B, such as the cooling pump 104 and the P/S pump 106. The torque command Ta* of the auxiliary motor 40 is set equal to the sum of the output torque command Td* and the rotational torque TST required to rotate the crankshaft 56 at the predetermined speed. The torque command Tc* of the clutch motor 30 is generally set equal to the output torque command Td*. Accordingly, the driver does not feel the reduction in torque due to rotation of the crankshaft 56, but receives the torque corresponding to the amount of operation of the accelerator pedal 64. While the internal combustion engine 50 stops its operation, the intake valve and the exhaust valve of the internal combustion engine 50 are closed to minimize the energy consumption in the internal combustion engine 50.

In the power output device 20B of Fig. 11, which is given as the second embodiment explained above, the auxiliary motor 40 is fixed to the crankshaft 56, which is located between the engine 50 and the clutch motor 30. However, as in another power output device 20C shown in Fig. 14, the engine 50 may be interposed between the clutch motor 30 and the auxiliary motor 40, both of which are connected to the crankshaft 56. In this structure, the auxiliary equipment such as the cooling pump 104 and the P/S pump 106 are fixed to the crankshaft 56B. which extends further from the crankshaft 56.

In the power output device 20B of Fig. 11, the clutch motor 30 and the auxiliary motor 40 are separately fixed to different positions of the crankshaft 56. However, as in a power output device 20D shown in Fig. 15, the clutch motor and the auxiliary motor may be integrally connected to each other. A clutch motor 30D of the power output device 20D has an outer rotor 32D that connects to the crankshaft 56 and an inner rotor 34 that connects to the drive shaft 22. Three-phase coils 36 are fixed to the inner rotor 34; 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. An 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 power output device 20D, 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 35D arranged on the outer rotor 32D. This enables the clutch motor 30D to operate in the same manner as the clutch motor 30 of the power output device 20B shown in Fig. 11. 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 40 of the power output device 20B. The torque control routine of Fig. 12 and the engine stopping time torque control routine of Fig. 13 are also applicable to the power output device shown in Fig. 15. 20D, which accordingly implements the same operations and has the same effects as the energy output device 20B shown in Fig. 11.

As with the energy output device 20A shown in Fig. 10, the outer rotor 32D in the energy output device 20D of Fig. 15 simultaneously functions as one of the rotors in the clutch motor 30D and as the rotor of the auxiliary motor 40D, thereby effectively reducing the size and weight of the entire energy output device 20D.

Many other modifications, variations and changes may be made within the scope of those skilled in the art without departing from the scope of the essential characteristics of the invention. It is therefore to be understood that the foregoing embodiments are only illustrative and not restrictive in any respect.

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

Permanent magnet (PM) type synchronous motors are used for the clutch motor 30 and the auxiliary motor 40 in the above-described power output device. Other motors such as variable reluctance (VR) synchronous motors, fine-tuning motors, DC motors, induction motors, superconducting motors and stepping motors can be used for the regenerative operation and power operation.

The rotary converter 38, which is used as a device for transmitting electrical energy to the clutch motor 30 can be replaced by a slip ring-brush contact, a slip ring-mercury contact, a semiconductor coupling of magnetic energy or similar.

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

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

Claims (11)

1. Energy delivery device (20) for delivering energy to a drive shaft (22), the energy delivery device (20) comprising: an internal combustion engine (50) with an output shaft (56), a first motor (30) with a first rotor (32, 34A) connected to the output shaft (56) of the internal combustion engine and a second rotor (34, 32A) connected to the drive shaft (22), the second rotor being arranged coaxially and rotatably with respect to the first rotor, the first and second rotors being electromagnetically connected 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 connection of the first and second rotors, a first motor drive circuit (91) for controlling a degree of electromagnetic connection of the first rotor and the second rotor in the first motor (30) and for regulating rotation of the second rotor with respect to the first rotor, a second motor (40) with a stator (43), wherein the rotor of the second motor is also the second rotor of the first motor or the rotor of the second motor is a third rotor which is connected to the drive shaft (22), a second motor drive circuit (92) for driving and controlling the second motor (40), a storage battery (94) which is charged with the electrical energy generated by the first motor (30) via the drive circuit (91) for the first motor, which is charged with the electrical energy generated by the second motor (40) via the drive circuit (92) for the second motor, the electrical energy required to drive the first motor (30) via the drive circuit (91) for the first motor discharges and the electrical energy required to drive the second motor (40) is discharged via the drive circuit (92) for the second motor, marked by an auxiliary system (104, 106) connected to the output shaft (56) of the internal combustion engine and driven by the energy of the output shaft, and an auxiliary system control device (90) for controlling the drive circuit (91) for the first motor to enable the first motor (30) to apply a torque (TST) to the output shaft (56) of the internal combustion engine with the energy stored in the storage battery (94) while the internal combustion engine stops operating, the torque (TST) enabling the output shaft (56) of the internal combustion engine to rotate at a predetermined speed. 2. Energy delivery device according to claim 1, wherein the torque (TST) is a first torque (Tc*), and the auxiliary equipment control device (90) comprises means for controlling the drive circuit (92) for the second motor to enable the second motor (40) to apply a second torque (Ta*) to the drive shaft (22) to reduce a change in the torque of the drive shaft (22) caused by the rotation of the output shaft (56) of the internal combustion engine at the predetermined speed. 3. The power output device of claim 2, wherein the auxiliary equipment control means (90) includes means for controlling the drive circuit (92) for the second motor to enable the second motor to apply the second torque (Ta*) to the drive shaft (22) as a sum of a third torque (Ts*) and a fourth torque (TST), the third torque (Td*) is applied to rotate the drive shaft (22) and the fourth torque (TST) has a magnitude substantially equal to the first torque (Tc*) applied by the first motor (30) to rotate the output shaft (56) of the internal combustion engine at the predetermined speed (Nc), but is directed opposite to the first torque (Tc*). 4. Energy output device according to one of the preceding claims, wherein when the rotor of the second motor is the second rotor (32A) of the first motor, the first and second motors form a complex motor. 5. Energy delivery device (20) for delivering energy to a drive shaft (22), the energy delivery device (20) comprising: an internal combustion engine (50) with an output shaft (56) a first motor (30) with a first rotor (32, 32D) connected to the output shaft (56) of the internal combustion engine and a second rotor (34) connected to the drive shaft (22), the second rotor being arranged coaxially and rotatably with respect to the first rotor, the first and second rotors being electromagnetically connected 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 connection of the first and second rotors, a first motor drive circuit (91) for controlling a degree of electromagnetic connection of the first rotor and the second rotor in the first motor (30) and for regulating rotation of the second rotor with respect to the first rotor, a second motor (40) having a stator (43), wherein the rotor of the second motor is also the first rotor (32D) of the first motor or the rotor of the second Motor is a third rotor which is connected to the output shaft (56) of the internal combustion engine (56), a second motor drive circuit (92) for driving and controlling the second motor (40), a storage battery (94) which is charged with the electrical energy generated by the first motor (30) via the drive circuit (91) for the first motor, which is charged with the electrical energy generated by the second motor (40) via the drive circuit (92) for the second motor, which discharges the electrical energy required to drive the first motor (30) via the drive circuit (91) for the first motor, and which discharges the electrical energy required to drive the second motor (40) via the drive circuit (92) for the second motor, marked by an auxiliary system (104, 106) which is connected to the output shaft (56) of the internal combustion engine and is driven by the energy of the output shaft, and an auxiliary equipment control device (90) for controlling the drive circuit (92) for the second motor to allow the second motor (40) to apply a torque (TST) to the output shaft (56) of the internal combustion engine with the energy stored in the storage battery (94) while the internal combustion engine stops operating, the torque (TST) allowing the output shaft (56) of the internal combustion engine to rotate at a predetermined speed. 6. The power output device of claim 5, wherein the torque is a first torque (Ta*), and the auxiliary equipment control means (90) includes means for controlling the drive circuit (92) for the second motor to enable the second motor (40) to apply to the output shaft of the internal combustion engine the first torque (Ta*) which is greater than a second Torque (Td*) applied by the first motor (30) to the drive shaft (22). 7. The energy output device according to claim 5 or 6, wherein, when the rotor of the second motor is the first rotor (32D) of the first motor, the first and second motors form a complex motor. 8. A method for controlling an energy delivery device (20) for delivering energy to a drive shaft (22), the method comprising the steps: a) providing an internal combustion engine (50) with an output shaft (56), a first motor (30) with a first rotor (32, 34A) connected to the output shaft (56) of the internal combustion engine and a second rotor (34, 32A) connected to the drive shaft (22), the second rotor being arranged coaxially and rotatably with respect to the first rotor, the first and second rotors being electromagnetically connected 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 connection of the first and second rotors, a second motor (40) with a stator (43), wherein the rotor of the second motor is also the second rotor of the first motor or the rotor of the second motor is a third rotor which is connected to the drive shaft (22), and a storage battery (94) which is charged with the electrical energy generated by the first motor (30), which is charged with the electrical energy generated by the second motor (40), which discharges the electrical energy required to drive the first motor (30), and which discharges the electrical energy required to drive the second motor (40), and an auxiliary system (104, 106) which is connected to the output shaft (56) of the internal combustion engine (50) and is driven by the energy of the output shaft, marked by (b) controlling the first motor (30) to enable the first motor (30) to apply a torque (TST) to the output shaft (56) of the internal combustion engine with the energy stored in the storage battery (94) while the internal combustion engine stops operating, the torque enabling the output shaft (6) of the internal combustion engine to rotate at a predetermined speed. 9. The method of claim 8, wherein the torque (TST) is a first torque (Tc*) and Step (b) additionally comprises controlling the second motor (40) to apply a second torque (Ta*) to the drive shaft (22) as a sum of the third torque (Td*) and a fourth torque (TST), the third torque (Td*) being applied to rotate the drive shaft (22) and the fourth torque (TST) having a magnitude substantially equal to the first torque (Tc*) applied by the first motor (30) to rotate the output shaft (56) of the internal combustion engine at the predetermined speed (Nc), but opposite to the first torque (Tc*). 10. A method for controlling an energy delivery device (20) 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 (32, 32D) connected to the output shaft (56) of the internal combustion engine and a second rotor (34) connected to the drive shaft (22), the second rotor being arranged coaxially and rotatably with respect to the first rotor, the first and second rotors being electromagnetically connected to one another, whereby energy is transmitted between the output shaft of the internal combustion engine and the drive shaft via the electromagnetic connection of the first and second rotors, a second motor with a stator (43), wherein the rotor of the second motor is also the first rotor of the first motor or the rotor of the second motor is a third rotor which is connected to the output shaft (56) of the internal combustion engine, and a storage battery (94) which is charged with the electrical energy generated by the first motor (30), which is charged with the electrical energy generated by the second motor (40), which discharges the electrical energy required to drive the first motor (30), and which discharges the electrical energy required to drive the second motor (40), and an auxiliary system (104, 106) which is connected to the output shaft (56) of the internal combustion engine (50) and is driven by the energy of the output shaft marked by (b) controlling the second motor (40) to enable the second motor (40) to apply torque to the output shaft (56) of the internal combustion engine with the energy stored in the storage battery (94) while the internal combustion engine stops operating, the torque enabling the output shaft (56) of the internal combustion engine to rotate at a predetermined speed. 11. The method of claim 10, wherein the torque (TST) is a first torque (Ta*) and Step (b) additionally comprises controlling the second motor (40) to enable the second motor (40) to apply to the output shaft of the internal combustion engine the first torque (Ta*) which is greater than a second torque (Td*) applied by the first motor (30) to the drive shaft (22).