(195 Q
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`(12)
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`Europalsches Patentamt
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`European Patent Ottice
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`Office européen des brevets
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`||||l|V|Illllilflllflillillllllllflllllllitfllllflllllllllilllllilllll
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`(11)
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`EP 0 743 211 A2
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`EUROPEAN PATENT APPLICATION
`
`(43) Date of publication:
`20.11.1996 Bulletin 1996/47
`
`(21) Application number: 96108009.0
`
`(22) Date of filing: 2o.o5.199s
`
`(84) Designated Contracting States:
`DE FR GB
`
`(30) Priority: 19.05.1995 JP 145575/95
`09.08.1995 JP 2258G9l95
`29.08.1995 JP 245462/95
`29.08.1995 JP 245463/95
`29.08.1995 JP 245464/95
`04.09.1995 JP 251944/95
`19.09.1995 JP 266475/95
`22.09.1995 JP 269241/95
`22.09.1995 JP 269242/95
`22.09.1995 JP 269243/95
`24.10.1995 JP 3(XJ742/95
`15.12.1995 JP 347852l95
`
`(71) Applicant: TOYOTA JIDOSHA KABUSHIKI
`KAISHA
`Aichi-ken 471 (JP)
`
`
`
`(51) Int. CL‘: B60K 6/04
`
`(72) Inventors:
`- Yamada, Eljl,
`clo Toyota Jldosha K.K.
`Toyota-shl, Alchi-ken, 471 (JP)
`- Miyatanl, Takao,
`.
`clo Toyota Jldosha K.K.
`Toyota-shl, Alchl-ken, 471 (JP)
`- Kawabata, Yasutomo,
`clo Toyota Jldosha K.K.
`Toyota-shl, Aichl-ken, 471 (JP)
`- Uchida, Masatoshi,
`clo Toyota Jldosha K.K.
`Toyota-shl, Alchl-ken, 471 (JP)
`
`(74) Representative: KUHNEN, WACKER & PARTNER
`Alois-Steinecker-Strasse 22'
`D-85354 Frelsing (DE)
`
`(54)
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`Hybrid vehicle power output apparatus and method ol controlling the same at engine Idle
`
`A power output apparatus (20) of the invention
`(57)
`includes an engine (50). a clutch motor (30). an assist
`motor (40). and a controller (80) for controlling the
`clutch motor (30) andthe assist motor (40). In response
`to an engine stop signal to stop operation of the engine
`(50), the controller (80) successively lowers a torque
`command value of the clutch motor (30) and a target
`engine torque and a target engine speed of the engine
`(50) to make the engine’(50) kept at an idle. The assist
`motor (40) is controlled to use power stored in a battery
`(94) and rrake up for a decrease in torque output to a
`drive shaft (22) accompanied by the decrease in torque
`command value of the clutch motor (30). When the
`engine (50) falls in the idling state. supply of fuel into the
`engine (50) is stopped to terminate operation of the
`engine (50). In this state. the drive shaft (22) is driven
`and operated only by the torque of the assist motor (40),
`which is generated by the power stored in the battery
`(94). This control procedure can stop the engine (50)
`without varying the torque output to the drive shaft (22).
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`Priniedby Rank xerox (UK) Business services
`2.13.8114
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`FORD EXHIBIT 1102
`FORD EXHIBIT 1102
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`EP0743211A2
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`EP0743211 A2
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`Description
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`BACKGROUND OF THE lNVEN‘l1ON
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`Field of the Invention
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`The present invention generally relates to a power output apparatus and a method of controlling the same. More
`specifically, the invention pertains to a power output apparatus for efficiently transmitting or outputting a power from an
`engine to a drive shaft and a method of controlling such a power output apparatus.
`
`Description of the Related Art
`
`In proposed power output apparatuses mounted on a vehicle. an output shaft of an engine is electromagnetically
`connected to a drive shaft linked with a rotor of a motor via an electromagnetic coupling, so that power of the engine is
`transmitted to the drive shaft (as disclosed in, for example. JAPANESE PATENT LAYING-OPEN GAZETTE No. 53-
`133814). \Nhen the revolving speed of the motor, which starts driving the vehicle, reaches a predetermined level. the
`proposed power output apparatus supplies an exciting current to the electromagnetic coupling in order to crank the
`engine, and subsequently carries out fuel injection into the engine as well as spark ignition. thereby starting the engine
`and enabling the engine to supply power. When the vehicle speed is lowered and the revolving speed of the motor
`decreases to or below the predetermined level. on the other hand. the power output apparatus stops the supply of excit-
`ing current to the electromagnetic coupling as well as fuel injection into the engine and spark ignition. thereby terminat-
`ing operation of the engine.
`-
`'
`In the known power output apparatus described above. the torque output to the drive shaft is significantly varied at
`the time of starting and stopping the engine. This results in a rough ride. At the time of starting the engine, the torque
`output from the motor is used to crank the engine. and the torque output to the drive shaft is decreased by the amount
`required for cranking. At the time of stopping the engine, -the supply of exciting current is stopped while the power from
`the engine is transmitted to the drive shaft via the electromagnetic coupling. and the torque output to the drive shaft is
`decreased by the amount of power transmitted from the engine. Such a fall in output torque occurs unexpectedly since
`the driver does not determine the time of -starting or stopping the engine. Corrpared with the expected variation. the
`unexpected variation in output torque to the drive shaft gives a greater shock to the driver. thereby resulting in a rough
`drive.
`
`SUMMARY OF THE INVEN'|1ON
`
`The object of the invention is thus to provide a power output apparatus which can transmit or output a power from
`an engine to a drive shaft at a high efficiency.
`Another object of the invention is to stop the engine without varying the torque output to the drive shaft. and a
`method of controlling such a power output apparatus.
`.
`The above and other related objected are realized at least partly by a first power output apparatus for outputting a
`power to a drive shaft. The first power output apparatus comprises: an engine having an output shaft; engine driving
`means for driving the engine; a first motor comprising a first rotor connected with the output staff of the engine and a
`second rotor connected with the drive shaft. the second rotor being coaxial to and rotatable relative tothe first rotor,
`whereby power is transmitted between the output shaft of the engine and the drive shaft via an electromagnetic con-
`nection of the first rotor and the second rotor; a first motor-driving circuit for controlling degree of electromagnetic con-
`nection of the first rotor and the second rotor in the first motor and regulating rotation of the second rotor relative to the
`first rotor; a second motor connected with the drive shaft; a second motor-driving circuit for driving and controlling the
`second motor; a storage battery being charged with power regenerated by the first motor via the first motor-driving cir-
`cuit. being charged with power regenerated by the second motor via the second motor-driving circuit. discharging power
`required to drive the first motor via the first motor-driving circuit. and discharging power required to drive the second
`motor via the second motor-driving circuit; power decrease signal detection meansfor detecting power decrease signal
`to decrease power output from the engine; driving circuit control means for, when the power decrease signal detection
`means detects the power decrease signal, controlling the first motor-driving circuit in response to the signal to gradually
`decrease the degree of electromagnetic connection of the first rotor with the second rotor in the first motor "and control-
`ling the second motor-driving circuit to enable the second motor to use power stored in the storage battery and make
`up for a decrease in power transmitted by the first motor accompanied by the decrease in degree of electromagnetic
`connection: and engine power decreasing means for controlling the engine driving means to decrease the power output
`from the engine with the decrease in the degree of electromagnetic connection of the first rotor with the second rotor
`accomplished by the driving circuit control means.
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`EPO743 211 A2
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`Thefirst power output apparatus of the invention can efficiently transmit or output the power front the engine to the
`drive shaft by the functions of the first and the second motors. In response to the power decrease signal. the degree of
`electromagnetic coupling of the first rotor with the second rotor in the first motor is gradually decreased. The second
`motor is then controlled to make up for the decrease in transmitted power. which is accorrpanied by the decrease in
`degree of electromagnetic coupling. with the power stored in the secondary cell. This structure effectively decreases
`the power output from the engine without varying the power output to the drive shaft.
`In accordance with one aspect of the first power output apparatus. the power decrease signal detection means
`comprises means for detecting an engine stop signal to stop operation of the engine. and the engine power decreasing
`means comprises means for controlling the engine driving means to stop supply of fuel into the engine and terminate
`operation of the engine when the driving circuit controlmeans releases the electromagnetic connection of the first rotor
`with the second rotor in the first motor.
`
`In accordance with one aspect. the present invention is directed to a second power output apparatus for outputting
`a power to a drive shaft. The second power output apparatus comprises: an engine having an output shaft; engine driv-
`ing means for driving the engine; a corrplex motor comprising afirst rotor connected with the output shaft of the engine.
`a second rotor connected with the drive shaft being coaxial to and rotatable relative to the first rotor, and a stator for
`rotating the second rotor, the first rotor and the second rotor constituting a first motor. the second rotor and the stator
`constituting a second motor; a first motor-driving circuit for driving and controlling the first motor in the complex motor:
`a second motor-driving circuit for driving and controlling the second motor in the complex motor; a storage battery being
`charged with power regenerated by the first motor via the first motor-driving circuit. being charged with power regener-
`ated by the second motor via the second motororiving circuit. discharging power required to drive the first motor via the
`first motororiving circuit. and discharging power required to drive the second motor via the second motor-driving circuit:
`power decrease signal detection means for detecting power decrease signal to decrease power output from the engine;
`driving circuit control means for. when the power decrease signal detection means detects the power decrease signal.
`controlling the first motorclriving circuit in response to the signal to gradually decrease the degree of electromagnetic
`connection of the first rotor with the second rotor in the first motor and controlling the second motor-driving circuit to
`enable the second motor to use power stored in the storage battery and make up for a decrease in power transmitted
`by the first motor accompanied by the decrease in degree of electromagnetic connection; and engine power decreasing
`mans for controlling the engine driving means to decrease the power output from the engine with the decrease in the
`degree of electromagnetic connection of the first rotor with the second rotor accomplished by the driving circuit control
`mans.
`
`The second poweroutput apparatus of the invention can efficiently transmit or output the power from the engine to
`the drive shaft by the functions of the first motor. which consists of the first rotor and the second rotor of the complex
`motor. and the second motor. which consists of the second rotor and the stator. In response to the power decrease sig-
`nal. the degree of electromagnetic coupling of the first rotor with the second rotor in the first motor is gradually
`decreased; The second motor is then controlled to make up for the decrease in transmitted power. whichis accompa-
`nied by the decrease in degree of electromagnetic coupling. with the power stored in the secondary cell..This structure
`effectively decreases the power output from the engine without varying the power output to the drive shaft. The struc-
`ture including the first motor and the second motor integrally joined with each other realizes a compact power output
`apparatus.
`In accordance with one aspect of the second power output apparatus. the power decrease signal detection means
`comprises means for detecting an engine stop signal to stop operation of the engine. and the engine power decreasing
`mans comprises means for controlling the engine driving means to stop supply of fuel into the engine and terminate
`operation of the engine when the driving circuit control means releases the electromagnetic connection of the first rotor
`with the second rotor in the first motor.
`
`In accordance with another aspect. the invention is also directed to a third power output apparatus for outputting a
`power to a drive shaft. The third power output apparatus comprises: an engine having an output shaft; engine driving
`mans for driving the engine; a first motor comprising a first rotor connected with the output shaft of the engine and a
`second rotor connected with the drive shaft. the first motor being coaxial to and rotatable relative to the first rotor.
`whereby power is transmitted between the output shaft of the engine and the drive shaft via an electromagnetic con-
`nection of the first rotor and the second rotor; a first motor-driving circuit for controlling degree of electromagnetic con-
`nection of the first rotor and the second rotor in the first motor and regulating rotation of the second rotor relative to the
`first rotor: a second motor connectied with the output shaft of the engine; a second motor-driving circuit for driving and
`controlling the second motor; a storage battery being charged with power regenerated by the first motor via the first
`motor-driving circuit. being charged with power regenerated by the second motor via the second motor-driving circuit.
`discharging power required to drive the first motor via the first motor-driving circuit. and discharging power required to
`drive the second motor via the second motor-driving circuit; power decrease signal detection means for detecting power
`decrease signal to decrease power output from the engine; engine power decreasing means for. when the power
`decrease signal detection mans detects the power decrease signal. controlling the engine driving means in response
`to the signal to gradually decrease the power output from the engine; and driving circuit control means for controlling
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`EP0743 211 A2
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`the first motor-driving circuit and the second motor-driving circuit to enable the first motor and the second motor to use
`power stored in the storage battery and make up for the decrease in power output from the engine accomplished by the
`engine power decreasing means.
`.
`The third power output apparatus of the invention can efficiently transmit or output the power from the engine to the
`drive shaft by the functions of thefirst and the second motors. in response to the power decrease signal, the power out-
`put lrom the engine is gradually decreased. The first motor and the second motor are then controlled to make up for the
`decrease in power output from the engine with the power stored in the secondary cell. This structure effectively
`decreases the power output from the engine without varying the power output to the drive shaft
`In accordance with one aspect of thethird power. output apparatus. the driving circuit control means comprises
`meane for.-controlling the first motor-driving circuit to enable the first motor to make up for a decrease in revolving speed
`of the output shaft of the engine among the decrease in power output from the engine, and controlling the second
`motor-driving circuit to enable the second motor to make up for a decrease in torque among the decrease in power out-
`put from the engine. lnthis structure, the power decrease signal detection means comprises meane for detecting an
`engine stop signal to stop operation ofthe engine. and the engine power decreasing means comprises meane for con-
`trolling the engine driving means to stop supply of fuel into the engine and terminate operation of the engine when the
`power output from the engine becomes equal to zero.
`In accordance with still another aspect, the invention also provides a fourth power output apparatus for outputting
`a power.to a drive shaft The fourth power output apparatus comprises: an engine having an output shaft; engine driving
`means for driving the engine; a complex motor comprising a first rotor connected with the output shaft of the engine, a
`second rotor connected with the drive shaft being coaxial to and rotatable relative to the firstrotor. and a stator for rotat-
`ing the first rotor, the first rotor and the second rotor constituting a first motor, the first rotor and the stator constituting a
`second motor;-.a first motor-driving circuit for driving and controlling the first motor in the complex motor: a second
`motor-driving circuit for driving and controlling the second motor in the complex motor:
`a storage battery being charged with power regenerated by the first motor via the first motor-driving circuit. being
`charged with power regenerated by the second motor via the second motor-driving circuit, discharging power required
`to drive thefirst motor. via the -first motor-driving circuit. and discharging power required to drive the second motor via
`the second .motor-driving circuit; power decrease signal detection means for detecting power decrease signal to
`decreasepower. output from the engine; engine power decreasing means for, when the power-decrease signal detec-
`tion means detects-the_ power decrease signal, controlling the enginedriving meansin response to the signal to grad-
`ually decrease the power output from the engine; and driving circuit control means for controlling the first motordriving
`circuit andthe second motor-driving circuit to enable the first motor and the second motor to use power stored in the
`storage-battery and make up for the decrease in power output from the engine accomplished by the enginepower
`decreasing means.
`‘
`Thetourth power output apparatus of the invention can efficiently transmit-or output the power from the engine to
`the drive shaft by the functions of the first motor, which consists of the first rotor and the second rotor of the complex
`motor, am the second motor.--which consists of the first rotor and the stator. in response to the power decrease signal.
`the power output trom the engine is gradually decreased. The first motor and the second motor are then controlled to
`make up for the decrease in power output from the engine with the power stored in the secondary cell. This structure
`effectively decreases the power output from the engine without varying the power output to the drive shaft The struc-
`ture including the first motor and the second motor integrally joined with each other realizes a compact power output
`apparatus.
`In accordance with one aspect of the fourth power output apparatus,the driving circuit control means comprises
`means for controlling the first motor-driving circuit to enable the first motor to make up for a decrease in revolving speed
`of the output shaft of the engine among the decrease in power output from the engine. and ‘controlling-the second
`motor-driving circuit toenable the second motor to make up for a decrease in torque among the decreasein power out-
`put from the-engine. In this structure.the power decrease signal detection means comprises means for detecting ‘an
`engine stop signal to stop operation of the engine. and -the engine power decreasing means comprises means for con-
`trolling the engine driving means to stop supply of fuel into the engine and terminate operationof the engine when the
`power output from the engine becomes equal to zero.
`The above objects are also realized at least partly by a first method of controlling a power output apparatus for out-
`putting a power to a drive shaft The first method comprises the steps of: (a) providing an engine having an output shaft:
`engine driving means for driving the engine;.a first motor comprising a first rotor connected with the outputshaft of the
`engine and a-second rotor comected with the drive shaft. the first motor being coaxial to and rotatable relative to the
`first rotor. whereby power is transmitted between the output shaft of the engine and the drive shaft via an electromag-
`netic comection of the firstrotor and the second rotor; a second motor connected with the drive shaft: and a storage
`battery being charged with power regenerated by the firstmotor, being charged with power regenerated by the second
`motor, discharging power required to drive the first motor. _and discharging power required to drive the second motor;
`(b) detecting power decrease signal to decrease power output from the engine; (c) controlling the first motor in
`response to the power decrease sigml, to gradually decrease the degree of electromagnetic comection of the first rotor
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`EPO 743 211 A2
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`with the second rotor in the first motor; (d) controlling the second motor to enable the second motor to use power stored
`in the storage battery and make up for a decrease in power transmitted by the first motor acconpanied by the decrease
`in degree of electromagnetic connection: and (a) controlling the engine driving means to decrease the power output
`from the engine with the decrease in degree of electromagnetic connection of the first rotor with the second rotor
`accomplished in the step (c).
`In accordance with one aspect of the first method. the power decrease signal detected represents an engine stop
`signal to stop operation of the engine. and the step (e) further comprises the step of controlling the engine driving
`means to stop supply of fuel into the engine and terminate operation of the engine when the electromagnetic connec-
`tion of the first rotor with the second rotor in the first motor has been decreased to a release position in response to the
`engine stop signal.
`In accordance with one aspect. the invention is also directed to a second method of controlling a power output
`apparatus tor outputting a power to a drive shaft The second method comprises the steps of: (a) providing an engine
`having an output-shaft; engine driving means for driving the engine; a first motor comprising a first rotor connected with
`the output shaft of the engine and a second rotor connected with the drive shaft. the second rotor being coaxial to and
`rotatable relative to the first rotor. whereby power is transmitted between the output shaft of the engine and the drive
`shaft via an electromagnetic connection of the first rotor and the second rotor; a second motor connected with the out-
`putshalt of the engine; and a storage battery being charged with power regenerated by the first motor. being charged
`with power regenerated by the second motor. discharging power required to drive the first motor. and discharging power
`required to drive the second motor; (b) detecting power decrease signal to decrease power output from the engine; (c)
`controlling the engine driving means in response to the power decrease signal. to gradually decrease the power output
`from the engine; and (d) controlling the first motor and the second motor to enable the first motor and the second motor
`to use power stored in the storage battery and make up for the decrease in power output from the engine accomplished
`in the step (c).
`In accordance with one aspect of the second method. the step (d) further comprises the steps of: (e) controlling the
`first motor to enable thefirst motor to make up for a decrease in revolving-speed of the output shaft of the engine among
`the decrease in power output from the engine; and (f) controlling the second motor to enable the second motor to make
`up for a decrease in torque among the decrease in power output from the 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.
`'
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`Fig. 1 is a schematic view illustrating structure of a power output apparatus 20 as a first embodiment accordingto
`the present invention;
`Fig; 2 is a cross sectional view illustrating detailed structures of a clutch motor 30 and an assist motor 40 included
`in the power output apparatus 20 of Fig. 1;
`Hg. 3 is a schematic view illustrating general structure of a vehicle with the power output apparatus 20 of Fig. 1
`incorporated therein;
`Fig. 4 is a graph showing the operation principle of the power output apparatus 20:
`Fig. 5 is a flowchart showing a torque control routine executed by the controller 80;
`Fig. 6 is a flowchart showing essential steps of controlling the clutch motor 30 executed by the controller 80; -
`Figs. 7 and 8 are flowcharts showing essential steps of controlling the assist motor 40 executed by the controller 80;
`-5 Fig. 9 is a flowchart showingan engine stop-time torque control routine executed by the controller 80;
`Fig. 10 is a flowchart showing essential steps of controlling the assist motor 40 executed by the controller 80 when
`the engine 50 stops operation:
`‘
`Fig. 11 schematically illustrates a power output apparatus 20A as a modification of the first embodiment;
`Fig. 12 schematically illustrates structure of another power output apparatus 208 as a second embodiment accord-
`_ ing to the present invention;
`Fig. 13 is a flowchart showing a torque control routine executed by the controller 80 in the second ernbcdiment;
`-A Fig. 14 is a flowchart showing an engine stop-time torque control routine executed by the controller 80 in the sec-
`ond embodiment;
`‘*3 Fig. 15 schematically illustrates a power output apparatus 20C as a modification of the second embodiment; and
`Fig. 16 schematically illustrates a power output apparatus 200 as another modification of the second embodiment.
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`55 DESCRIPTION OF THE PREFERRED EMBODIMENTS A
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`Fig. 1 is a schematic view illustrating structure of a power output apparatus 20 as a first embodiment according to
`the present invention; Fig. 2 is a cross sectional view illustrating detailed structures of a clutch motor 30 and an assist
`motor 40 included in the power output apparatus 20 of Fig. 1; and Fig. 3 is a schematic view illustrating a general struc-
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`EP0743 211 A2
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`ture of a vehicle with the power output apparatus 20 of Fig. 1 incorporated therein. The general structure of the vehicle
`is descrflaed first as a matter of convenience.
`Referring to Fig. 3. the vehicle is provided with an engine 50 driven by gasoline as a power source. The air ingested
`from an air supply system via a throttle valve 66 is mixed with fuel, that is. gasoline in this embodiment. injected from a
`fuel injection valve 51. The air/fuel mixture is supplied into a corrbustion chamber 52 to be explosively ignited and
`burned. Linear motion of a piston 54 pressed down by the explosion of the airlfuel mixture is converted to rotational
`motion of a crankshaft 56. The throttle valve 66 is driven to open and close by an actuator 68. An ignition plug 62 con-
`verts a high voltage applied from an igniter 58 via a distributor 60 to a spark. which explosively ignites and combusts
`the airlluel mixture.
`Operation of the engine 50 is controlled by an electronic control unit (hereinafter referred to as EFIECU) 70. The
`EFIECU 70 receives information from various sensors, which detect operating conditions of the engine 50. These sen-
`sors include a throttle valve position sensor 67 for detecting the position of the throttle valve 66. a manifold vacuum sen-
`sor 72 for measuring a load applied to the engine 50, a water temperature sensor 74 for measuring the temperature of
`cooling water in the engine 50, and a speed sensor 76 and an angle sensor 78 mounted on the distributor 60 for meas-
`uring the revolving speed and rotational angle of the crankshaft 56. A starter switch 79 for detecting a starting condition
`ST of an ignition key (not shown) is also connected to the EFIECU 70. Other sensors and switches connecting with the
`EFIECU 70 are omitted from the drawings.
`The crankshaft 56 of the engine 50 is linked with a drive shaft 22 via aclutch motor 30 and an assist motor 40
`(described later in detail). The drive shaft 22 further connects with a differential gear 24. which eventually transmits the
`torque output from the drive shaft 22 of the power outputapparatus 20 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 includes an inter-
`nal control~CPU and receives inputs from a gearshift position sensor 84 attached to a gearshift 82 and an accelerator
`position sensor 65 attached to an accelerator pedal 64, as described later in detail. The controller 80 sends and
`receives a variety of data and information to and from the EFIECU 70 through communication. Details of the control pro-
`cedure including a communication protocol will be described later..
`Referring to Fig. 1. the power output apparatus 20 essentially includes the engine 50. the clutch motor 30 with an
`outer rotor 32 and an inner rotor 34. the assist motor 40 with a rotor 42. and the controller 80 for driving and controlling
`the clutch motor 30 and the assist motor 40. The outer rotor 32 of the clutch motor 30 is mechanicallyconnected to the
`crankshaft 56 of the engine 50. whereas the-inner rotor 34thereof is mechanically linked with the rotor 42 of the assist
`motor 40.
`
`As shown in Fig. 1, the clutch motor 30 is constructed as a synchronous motor having permanent magnets‘35
`attached to an inner surface of the outer rotor 32 and three-phase coils 36 wound on slots formed in the inner rotor 34.
`Power is supplied to the_ three-phase coils 36 via a rotary transformer 38. A thin laminated sheet of non—directional elec-
`tromagnetic steel is used to form teeth and slots for the three-phase coils 36 in the inner rotor 34. A resolver 39 for
`measuring arotational angle (to of the crankshaft 56 isattached to" the crankshaft 56. The resolver 39 may also serve
`as the angle sensor 78 mounted on the distributor 60.
`The assist motor 40 is alsoconstructed as a synchronous motor having three-phase coils 44, which are wound on
`a stator 43 fixed to a casing 45 to generate a rotating magnetic field. The stator 43 is also made of a thin laminated
`sheetof non—directional electromagnetic steel. A plurality of permanent magnets 46 are attached to an outer surface of
`the rotor 42. In the assist motor 40. interaction between a magnetic field formed by the permanent magnets-46-and a
`rotating magnetic field formed by the three-phase coils 44 leads to rotation of the rotor 42. The rotor 42‘is mechanically
`linked with the drive shaft 22 working as the torque output shaft of the power output apparatus 20. A resolver 48 for
`measuring a rotational _angle ed of—the drive shaft 22 is attached to the drive shaft 22. which is further supported by a
`bearing 49 held in the casing 45.
`-
`—
`The inner rotor 34 of the clutch motor 30 is mechanically linked with the rotor 42 of the assistmotor 40 and further
`with the drive shaft-22. When the rotation and axial torque of the crankshaft 56 of the engine 50 are transmitted via the
`outer rotor 32 to-the inner.rotor 34 of the clutch motor 30. the rotation and torque by the assist motor 40“are added to
`or subtracted from the transmitted rotation and torque.
`While the assist motor 40 is constructed as a conventionalpermanent magnet-type.three-phasesynchronous
`motor, the clutch motor 30 includes two rotating elements or rotors. that is. the outer rotor 32 with the permanent mag-
`nets 35 and the inner rotor 34 with the three-phase coils 36. The detailed structure of the clutch motor 30 is described
`with the cross sectional view of Fig. 2. The outer rotor 32 of the clutch motor 30 is attached to acircurnferential end of
`a wheel 57 set around the crankshaft 56. by means of a pressure pin 59a and a screw 59b.- A central portion of the
`wheel 57 is protruded to form a shaft-like element. to which the inner rotor 34 is rotatably attached by means of bearings
`37A and 378. One end of the drive shaft 22 is fixed to the inner rotor 34.
`
`A plurality of permanent magnets 35. four in this embodiment. are attached to the inner surface of the outer rotor
`32 as mentioned previously. ‘The