Vehicle driving system

First and second engines ENG1 and ENG2; first and second transmissions TM1 and TM2 shifting the output of the first and second engines; first and second one-way clutches OWC1 and OWC2 that are provided in each output portion of the first and second transmissions; a driving target member 11 commonly connected to the output members 121 of the first and second one-way clutches via clutch mechanisms CL1 and CL2 and transmits the rotational power transmitted to the output members of the one-way clutches to the driving wheel 2; a main motor/generator MG1 connected to the member 11; a sub motor/generator MG2 connected to the output shaft S1 of the first engine; a battery 8 sending/receiving the electric power between both motor/generators; a synchronization mechanism 20 connecting/disconnecting the member 11 and the output shaft S2 of the second engine; and a controller 5.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a National Stage entry of International Application No. PCT/JP2011/060787 filed May 10, 2011, which claims priority to Japanese Patent Application Nos. 2010-136542, 2010-136544 and 2010-136549 filed Jun. 15, 2010, the disclosure of the prior applications are hereby incorporated in their entirety by reference.

TECHNICAL FIELD

The present invention relates to a vehicle driving system that includes plural internal combustion engines.

BACKGROUND ART

As a vehicle driving system of the related art, various systems are known (e.g., see PTLs 1 to 3). Among them, a system in PTL 1 is configured such that two engines, a first engine and a second engine, are mounted as a driving source. When the necessary torque is small, only the first engine is operated, an output thereof is input into a transmission, and when the necessary torque is large, by additionally operating the second engine section, the outputs of both engines are synthesized and input into the transmission, whereby the necessary torque is produced under an optimal condition depending on the load situation to improve the fuel efficiency of a vehicle.

A system in PTL 2 is configured such that power of an engine (substantially, considered as two engines) having two pistons of different strokes is input into the transmission in parallel via a one-way clutch and is transmitted to an output shaft.

PRIOR ART LITERATURE

Patent Literature

SUMMARY OF INVENTION

Problem to be Solved by Invention

Since the driving devices in PTLs 1 and 2 are configured such that the powers of two independent engines or substantially two engines are synthesized and input into the transmission, it is impossible to individually change the rotation number or the like of each engine in respect to the required output. For that reason, it is not possible to operate the engine in a high efficiency point, and there is a limitation on improving fuel efficiency.

The present invention was made in view of the above circumstances, and an object thereof is to provide a vehicle driving system which can reduce fuel consumption with higher efficiency.

Means for Solving Problem

Claim1defines a vehicle driving system (e.g., a driving system1in embodiment) including:

a first internal combustion engine section (e.g., a first engine ENG1in embodiment) and a second internal combustion engine section (e.g., a second engine ENG2in embodiment) that generate rotational powers, respectively;

a first transmission mechanism (e.g., a first transmission TM1in embodiment) and a second transmission mechanism (e.g., a second transmission TM2in embodiment) that output the generated rotational powers of the first internal combustion engine section and the second internal combustion engine section while changing speeds thereof, respectively;

a first one-way clutch (e.g., a first one-way clutch OWC1in embodiment) and a second one-way clutch (e.g., a second one-way clutch OWC2in embodiment) that are provided in the output portions of the first transmission mechanism and the second transmission mechanism, respectively, each one-way clutch having:an input member (e.g., an input member122in embodiment) that receives the rotational powers from the first transmission mechanism and the second transmission mechanism;an output member (e.g., an output member121in embodiment); andan engagement member (e.g., a roller123in embodiment) that makes the input member and the output member enter a locked state or an unlocked state with each other, so that the input member and the output member enter the locked state when a rotational speed of a positive direction of the input member exceeds a rotational speed of a positive direction of the output member, thereby transmitting the rotational power from the input member to the output member; and

a driving target member (e.g., a driving target member11in embodiment) that is commonly connected to the output members of the first one-way clutch and the second one-way clutch and transmits the rotational power to be transmitted to the output members of each one-way clutch to a driving wheel (e.g., a driving wheel2in embodiment),

wherein the generated rotational powers of the first internal combustion engine section and the second internal combustion engine section are input to the first one-way clutch and the second one-way clutch via the first transmission mechanism and the second transmission mechanism, respectively, and the rotational powers are input to the driving target member via the first one-way clutch and the second one-way clutch, respectively.

Claim2defines, based on claim1, the system,

wherein the first transmission mechanism and the second transmission mechanism are constituted by continuously variable transmission mechanisms (e.g., continuously variable transmission mechanisms BD1and BD2in embodiment) that can be changed in a non-step manner.

Claim3defines, based on claim2, the system,

wherein the continuously variable transmission mechanism includes:an input shaft (e.g., an input shaft101in embodiment) that rotates around an input center axis (e.g., an input center axis O1in embodiment) by receiving the rotational power;plural first fulcrums (e.g., a first fulcrum O3in embodiment) that are provided in a circumferential direction of the input shaft at equal intervals, are able to change an eccentricity (e.g., an eccentricity r1in embodiment) with respect to the input center axis, respectively, and rotate together with the input shaft around the input center axis while maintaining the eccentricity;plural eccentric disks (e.g., an eccentric disk104in embodiment) that hold the first fulcrums as the centers, respectively, and rotate around the input center axis;a one-way clutch (e.g., a one-way clutch120in embodiment) that has an output member (e.g., an output member121in embodiment) that rotates around an output center axis (e.g., an output center axis O2in embodiment) separated from the input center axis, an input member (e.g., an input member122in embodiment) that is oscillated around the output center axis by receiving the power of a rotational direction from the outside, and an engagement member (e.g., a roller123in embodiment) that makes the input member and the output member enter a locked state or an unlocked state with each other, and when the rotational speed of the positive direction of the input member exceeds the rotational speed of the positive direction of the output member, the one-way clutch transmits the rotational power, which was input into the input member, to the output member, thereby converting an oscillation movement of the input member to a rotational movement of the output member;a second fulcrum (e.g., a second fulcrum O4in embodiment) that is positioned separately from the output center axis of the input member;plural connection members (e.g., a connection member130in embodiment) that have one ends (e.g., a ring portion131in embodiment) connected to the outer peripheries of the eccentric disks so as to be rotatable around the first fulcrum and the other ends (e.g., the other end portion132in embodiment) connected to the second fulcrum provided on the input member of the one-way clutch so as to be rotatable, thereby transmitting the rotational movement, which is given from the input shaft to the eccentric disk, to the input member of the one-way clutch as an oscillation movement of the input member; anda transmission ratio variable mechanism (e.g., a transmission ratio variable mechanism112in embodiment) that changes an oscillation angle of the oscillation movement to be transmitted from the eccentric disk to the input member of the one-way clutch by adjusting the eccentricity of the first fulcrum with respect to the input center axis, thereby changing the transmission ratio when the rotational power to be input into the input shaft is transmitted to the output member of the one-way clutch via the eccentric disk and the connection member as the rotational power, and

wherein the continuously variable transmission mechanism is configured as a four bar linkage mechanism type of continuously variable transmission mechanism that can set the transmission ratio to infinity by setting the eccentricity to be zero, the output shaft (e.g., output shafts S1and S2in embodiment) of the internal combustion engine section is connected to the input shaft of the continuously variable transmission mechanism, and the one-way clutch which is a component of the continuously variable transmission mechanism also serves as the first one-way clutch and the second one-way clutch provided between the first transmission mechanism, the second transmission mechanism, and the driving target member, respectively.

Claim4defines, based on claim3, the system, further including:

clutch mechanisms (e.g., clutch mechanisms CL1and CL2in embodiment) that can transmit/disconnect the power between the output members of the first one-way clutch and the second one-way clutch and the driving target member.

Claim5defines, based on claim1, the system, further including:

a main motor/generator (e.g., a main motor/generator MG1in embodiment) connected to the driving target member.

Claim6defines, based on claim1, the system, further including:

a sub motor/generator (e.g., a sub motor/generator MG2in embodiment) connected to the output shaft of the first internal combustion engine section.

Claim7defines, based on claim1, the system, further including:

a main motor/generator connected to the driving target member; and

a sub motor/generator connected to the output shaft of the first internal combustion engine section.

Claim8defines, based on claim1, the system, further including:

clutch mechanisms that can transmit/disconnect the power between the output members of the first one-way clutch and the second one-way clutch and the driving target member.

Claim9defines, based on claim1, the system,

wherein the first and second internal combustion engine sections have high efficiency operation points different from each other.

Claim10defines, based on claim1, the system, further including:

a controller (e.g., a controller5in embodiment) configured to perform a synchronization control which controls the rotation number of the first and second internal combustion engine sections and/or the transmission ratios of the first and second transmission mechanisms so that the rotational speed to be input into both input members of the first one-way clutch and the second one-way clutch exceeds the rotational speed of the output member,

wherein the controller controls the first internal combustion engine section and/or the first transmission mechanism in the state of fixing an operation condition to a certain range so that the rotation number and/or the torque of the first internal combustion engine section enters a high efficiency operation region when performing the synchronization control, and controls the second internal combustion engine section and the second transmission mechanism depending on the output request exceeding the output to be obtained by the fixed operation condition.

Claim11defines, based on claim10, the system,

wherein a displacement of the first internal combustion engine section, to which the operation condition is fixed, is smaller than a displacement of the second internal combustion engine section.

Claim12defines, based on claim10, the system,

wherein a displacement of the first internal combustion engine section, to which the operation condition is fixed, is greater than a displacement of the second internal combustion engine section.

Claim13defines, based on claim10, the system,

wherein one of the first internal combustion engine section and the second internal combustion engine section is set to have a large displacement, and the other thereof is set to have a small displacement, and

wherein the controller performs the control so that, when the request output is equal to or greater than a predetermined value, the internal combustion engine section of the small displacement is set in the operation condition fixing side, and when the request output is equal to or less than a predetermined value, the internal combustion engine section of the large displacement is set in the operation condition fixing side.

Claim14defines, based on claim10, the system,

wherein the continuously variable transmission mechanism includes:an input shaft that rotates around the input center axis by receiving the rotational power;plural first fulcrums that are provided in a circumferential direction of the input shaft at equal intervals, are able to change an eccentricity with respect to the input center axis, respectively, and rotate together with the input shaft around the input center axis while maintaining the eccentricity;plural eccentric disks that hold the first fulcrums as the centers, respectively, and rotate around the input center axis;a one-way clutch that has an output member that rotates around an output center axis separated from the input center axis, an input member that is oscillated around the output center axis by receiving the power of a rotational direction from the outside, and an engagement member that makes the input member and the output member enter a locked state or an unlocked state with each other, and when the rotational speed of the positive direction of the input member exceeds the rotational speed of the positive direction of the output member, the one-way clutch transmits the rotational power, which was input into the input member, to the output member, thereby converting an oscillation movement of the input member to a rotational movement of the output member;a second fulcrum that is positioned separately from the output center axis on the input member;plural connection members that have one ends connected to the outer peripheries of the eccentric disks so as to be rotatable around the first fulcrum, and the other ends connected to the second fulcrum provided on the input member of the one-way clutch so as to be rotatable, thereby transmitting the rotational movement, which is given from the input shaft to the eccentric disk, to the input member of the one-way clutch as an oscillation movement of the input member; anda transmission ratio variable mechanism that changes an oscillation angle of the oscillation movement to be transmitted from the eccentric disk to the input member of the one-way clutch by adjusting the eccentricity of the first fulcrum with respect to the input center axis, thereby changing the transmission ratio when the rotational power to be input into the input shaft is transmitted to the output member of the one-way clutch via the eccentric disk and the connection member as the rotational power, and

wherein the continuously variable transmission mechanism is configured as a four bar linkage mechanism type of continuously variable transmission mechanism that can set the transmission ratio to infinity by setting the eccentricity to be zero, the output shaft of the internal combustion engine section is connected to the input shaft of the continuously variable transmission mechanism, and the one-way clutch which is a component of the continuously variable transmission mechanism also serves as the first one-way clutch mechanism and the second one-way clutch mechanism provided between the first transmission, the second transmission, and the driving target member, respectively.

Claim15defines, based on claim1, the system, further including:

a controller configured to perform a synchronization control which controls the rotation number of the first and second internal combustion engine sections and/or the transmission ratios of the first and second transmission mechanisms so that the rotational speed to be input into both input members of the first one-way clutch and the second one-way clutch exceeds the rotational speed of the output member.

Claim16defines, based on claim15, the system,

wherein the first transmission mechanism and the second transmission mechanism are constituted by continuously variable transmission mechanisms capable of changing the transmission ratio in a non-step manner.

Claim17defines, based on claim16, the system,

wherein the continuously variable transmission mechanism includes:an input shaft that rotates around the input center axis by receiving the rotational power;plural first fulcrums that are provided in a circumferential direction of the input shaft at equal intervals, are able to change an eccentricity with respect to the input center axis, respectively, and rotate together with the input shaft around the input center axis while maintaining the eccentricity;plural eccentric disks that hold the first fulcrums as the centers, respectively, and rotate around the input center axis;a one-way clutch that has an output member that rotates around an output center axis separated from the input center axis, an input member that is oscillated around the output center axis by receiving the power of a rotational direction from the outside, and an engagement member that makes the input member and the output member enter a locked state or an unlocked state with each other, and when the rotational speed of the positive direction of the input member exceeds the rotational speed of the positive direction of the output member, the one-way clutch transmits the rotational power, which was input into the input member, to the output member, thereby converting an oscillation movement of the input member to a rotational movement of the output member;a second fulcrum that is positioned separately from the output center axis on the input member;plural connection members that have one ends connected to the outer peripheries of the eccentric disks so as to be rotatable around the first fulcrum, and the other ends connected to the second fulcrum provided on the input member of the one-way clutch so as to be rotatable, thereby transmitting the rotational movement, which is given from the input shaft to the eccentric disk, to the input member of the one-way clutch as an oscillation movement of the input member; anda transmission ratio variable mechanism that changes an oscillation angle of the oscillation movement to be transmitted from the eccentric disk to the input member of the one-way clutch by adjusting the eccentricity of the first fulcrum with respect to the input center axis, thereby changing the transmission ratio when the rotational power to be input into the input shaft is transmitted to the output member of the one-way clutch mechanism via the eccentric disk and the connection member as the rotational power, and

wherein the continuously variable transmission mechanism is configured as a four bar linkage mechanism type of continuously variable transmission mechanism that can set the transmission ratio to infinity by setting the eccentricity to be zero, the output shaft of the internal combustion engine section is connected to the input shaft of the continuously variable transmission mechanism, and the one-way clutch which is a component of the continuously variable transmission mechanism also serves as the first one-way clutch and the second one-way clutch provided between the first transmission mechanism, the second transmission mechanism, and the driving target member, respectively.

Advantages of Invention

According to Claim1, since the respective first and second internal combustion engine portions are individually equipped with the transmission mechanisms, by combining the rotation number of the internal combustion engine section with the setting of the transmission ratio of the transmission mechanism, the output rotation number (the input rotation number of the input member of the one-way clutch) from the transmission mechanism can be controlled. Thus, the rotation number of each internal combustion engine section can be independently controlled depending on the setting of the transmission ratio of the transmission mechanism, and it is possible to operate each internal combustion engine section with effective movement point, respectively, which can contribute to improved fuel efficiency.

When the combination of “the internal combustion engine section and “the transmission mechanism” is called “a power mechanism”, since two sets of power mechanisms are connected to the same driving target member via the one-way clutch mechanism, respectively, the selective switch-over of the power mechanism to be used as a driving source or the synthesis of the driving forces from two power mechanisms can be executed only by performing the control of the input rotation number (the rotation number to be output from the power mechanism) with respect to each one-way clutch.

According to Claim2, since the continuously variable transmission mechanism shiftable in a non-step manner is used as the first and second transmission mechanisms, only by changing the transmission ratio of the transmission mechanism in a non-step manner while keeping the running state in a high efficiency operation point without changing the rotation number of the internal combustion engine section, it is possible to smoothly control ON/OFF of the power transmission from each power mechanism to the driving target member (“the connection and disconnection” of a power transmission path due to the locked state or the unlocked state of the one-way clutch are called “ON/OFF” for the sake of convenience).

In this regard, in the case of a step transmission mechanism, in order to smoothly control ON/OFF of the one-way clutch by changing the output rotation number of the power mechanism, there is a need to adjust the rotation number of the internal combustion engine portion to meet the transmission gear step. Meanwhile, in the case of the continuously variable transmission mechanism, since the output rotation number of the power mechanism can be smoothly changed only by adjusting the transmission ratio of the transmission mechanism in a non-step manner without changing the rotation number of the internal combustion engine section, it is possible to smoothly perform the switch-over of the driving source (the internal combustion engine section) due to ON/OFF of the power transmission between the power mechanism and the driving target member via the one-way clutch. Thus, it is possible to keep the operation of the internal combustion engine section in a running state having a satisfactory BSFC (Brake Specific Fuel Consumption).

According to Claims3,14, and17, by adopting the continuously variable transmission mechanism configured such that the rotational movement of the input shaft is converted to the eccentric rotational movement of the eccentric disk with the variable eccentricity, the eccentric rotational movement of the eccentric disk is transmitted to the input member of the one-way clutch via the connection member as the oscillation movement, and the oscillation movement of the input member is converted to the rotational movement of the output member of the one-way clutch, the transmission ratio can be increased to infinity only by changing the eccentricity. Thus, even if there is no clutch which separates the internal combustion engine section as the driving source from an inertial mass portion of a downstream side (output side), by setting the transmission ratio to infinity, when the internal combustion engine portion is started or the like, the inertial mass portion of the downstream side can be substantially separated from the internal combustion engine section. For that reason, the inertial mass portion of the downstream side (the output side) does not amount to resistance when the internal combustion engine section is started, but the starting of the internal combustion engine section can be smoothly performed.

By setting the transmission ratio to infinity, even if there is no clutch, substantially separating the internal combustion engine section from the inertial mass portion of the downstream side is particularly effective when connecting the main motor/generator to the driving target member to become hybrid. For example, in the case of shifting from an EV running, in which only the driving force of the main motor/generator is used, to a series running, in which the first internal combustion engine section is started, the sub motor/generator provided separately is driven by the driving force of the first internal combustion engine section, the electric power generated in the sub motor/generator is supplied to the main motor/generator, and the running is performed by the driving force of the main motor/generator, there is a need for the starting of the first internal combustion engine in the state of the EV running. However, since the resistance during starting internal combustion engine portion can be reduced as mentioned above, the shifting from the EV running to the series running can be smoothly performed without shock. By substantially separating the internal combustion engine section from the inertial mass portion of the downstream side, since the rotational resistance when executing the series running can be reduced, it is possible to reduce energy loss during series running and contribute to improved fuel efficiency.

In the case of adopting this type of continuously variable transmission mechanism, since the number of gears used can be reduced, energy loss due to engagement abrasion of the gears can be reduced.

According to Claims4and8, by causing the clutch mechanism to enter the disconnection state (called cutting state or OFF state), it is possible to separate the power transmission path of the upstream side from the power transmission path of the downstream side by the clutch mechanism. Thus, it is possible to prevent the drag of the one-way clutch which is not used in the wheel driving, whereby unnecessary energy loss can be reduced.

According to Claim5, since the main motor/generator is connected to the driving target member as the power source different from the internal combustion engine section, it is possible to perform the EV running only using the driving force of the main motor/generator. During EV running, the rotational speed of the positive direction of the output member exceeds the rotational speed of the positive direction of the input member in the first and second one-way clutches, the state of clutch OFF (unlocked state) is generated, and the power mechanism is separated from the driving target member.

When shifting from the EV running to the engine running using the driving force of the internal combustion engine section, the control is performed so that the input rotation number of the one-way clutch annexed to the internal combustion engine section using the driving force exceeds the rotation number of the driving target member that is driven by the main motor/generator. As a result, it is possible to easily switch over the running mode from the EV running to the engine running.

By synchronizing the rotation number to be input from the internal combustion engine section to the one-way clutch with the rotation number to be given from the main motor/generator to the driving target member, it is also possible to perform a parallel running which uses both the driving force of the internal combustion engine section and the driving force of the main motor/generator. Since it is also possible to start the internal combustion engine section by the use of the driving force of the main motor/generator, a separate starter device (e.g., a starter motor or the like) for the internal combustion engine can be omitted. By causing the main motor/generator to function as a generator when a vehicle is decelerated, since it is possible to cause a regeneration braking force to act on the driving wheel and obtain the regeneration braking power, an improvement in energy efficiency is also promoted.

According to Claim6, since the sub motor/generator is connected to the output shaft of the first internal combustion engine section, the sub motor/generator can be used as the starter of the first internal combustion engine section, and there is no need to provide a separate starter device for the internal combustion engine section. By using the sub motor/generator as a generator that generates electricity by the driving force of the first internal combustion engine section and supplying the generated electric power to the main motor/generator provided separately, the series running can also be performed.

According to Claim7, as the power source different from the internal combustion engine section, after the main motor/generator is connected to the driving target member, the sub motor/generator is connected to the output shaft of the first internal combustion engine section. Thus, besides the engine running using only the driving force of the internal combustion engine section, it is possible to select and execute various running modes such as the EV running that uses the driving force of the main motor/generator, the parallel running that uses the driving forces of both the internal combustion engine section and the main motor/generator in parallel, and the series running which supplies the electric power generated in the sub motor/generator to the main motor/generator using the driving force of the first internal combustion engine section and performs the running by the driving force of the main motor/generator.

According to Claim9, since the high efficiency operation points of the first and second internal combustion engine sections are different from each other, by preferentially selecting the internal combustion engine section having a high efficiency as the driving source, an overall improvement in energy efficiency can be promoted. To make the high efficiency operation points of the internal combustion engine portion different from each other, magnitudes of the displacement of the internal combustion engine section may be made different.

According to Claim10, when performing the synchronization control that synthesizes the driving forces of two internal combustion engine sections to drive the driving target member such as during high speed running, since at least one internal combustion engine section side (the first internal combustion engine section side) is operated in the high efficiency operation region, it is possible to contribute to improved fuel efficiency.

According to Claim11, even when there is a great fluctuation in the request output, since the internal combustion engine section side of high displacement copes with the great fluctuation, it is possible to reduce the delay depending on the request.

According to Claim12, since the internal combustion engine section of the large displacement is operated in the high efficiency operation scope, it is possible to further contribute to improved fuel efficiency.

According to Claim13, when the request output is great, the internal combustion engine section of the small displacement is set in the operation condition fixing side, and the internal combustion engine section side of the large displacement copes with the fluctuation in the request output. Thus, it is possible to reduce the delay depending on the request. When the request output is small, the internal combustion engine section of the large displacement is set in the operation condition fixing side, and the internal combustion engine section side of the small displacement copes with the fluctuation in the request output. Thus, it is possible to further contribute to improved fuel efficiency.

According to Claim15, when performing the engine running by the power synthesis of two internal combustion engine sections, only by performing the control so that the input rotation number of both the first one-way clutch and the second one-way clutch exceed the output rotation number, it is possible to easily input the great driving force, in which the outputs of two internal combustion engine sections are synthesized, into the driving target member to perform the running, without performing a special clutch operation.

According to Claim16, since the continuously variable transmission shiftable in the non-step manner is used as the first and second transmission mechanisms, it is possible to smoothly control ON/OFF of the power transmission from each driving mechanism to the driving target member (“the connection and disconnection” of a power transmission path due to the locked state or the unlocked state of the one-way clutch are called “ON/OFF” for the sake of convenience), only by changing the transmission ratio of the transmission mechanism in a non-step manner while keeping the running state in a high efficiency operation point without changing the rotation number of the internal combustion engine section. Thus, only by changing the transmission ratio of the transmission mechanism in the non-step manner, is it possible to smoothly perform the switch-over from the running using the driving force of the one internal combustion engine section to the running using the synthetic driving force of two internal combustion engine sections without shock.

In this regard, in the case of a step transmission mechanism, in order to smoothly control ON/OFF of the one-way clutch by changing the output rotation number of the power mechanism, there is a need to adjust the rotation number of the internal combustion engine portion to meet the transmission gear step. Meanwhile, in the case of the continuously variable transmission mechanism, since the output rotation number of the power mechanism can be smoothly changed only by adjusting the transmission ratio of the transmission mechanism in a non-step manner without changing the rotation number of the internal combustion engine section, it is possible to smoothly perform the switch-over of the driving source (the internal combustion engine section) due to ON/OFF of the power transmission between the power mechanism and the driving target member via the one-way clutch. Thus, it is possible to keep the operation of the internal combustion engine section in a running state having a satisfactory BSFC (Brake Specific Fuel Consumption).

DESCRIPTION OF EMBODIMENTS

Hereinafter, an embodiment of the present invention will be described based on the drawings.

FIG. 1shows a vehicle driving system of an embodiment of the present invention in a skeleton manner.FIG. 2cross-sectionally shows an infinite continuously variable transmission mechanism that is a major portion of the driving system.FIG. 3cross-sectionally shows a part of the infinite continuously variable transmission mechanism from an axial direction.

Overall Configuration

The vehicle driving system1includes two engines ENG1and ENG2as first and second internal combustion engine sections that generate the rotational power, respectively; first and second transmissions (transmission mechanism) TM1and TM2that are provided in each downstream side of the first and second engines ENG1and ENG2; first and second one-way clutches OWC1and OWC2that are provided in the output portions of the respective transmissions TM1and TM2; a driving target member11that receives the output rotation transmitted via the one-way clutches OWC1and OWC2; a main motor/generator MG1that is connected to the driving target member11; a sub motor/generator MG2that is connected to the output shaft S1of the first engine ENG1; a battery (storage)8that can send and receive the electric power between the main and/or sub motor/generators MG1and MG2; and a controller5that performs the control of the running pattern or the like by controlling various elements.

The respective one-way clutches OWC1and OWC2have an input member (an outer clutch)122, an output member (an inner clutch)121, plural rollers (engagement members)123that are disposed between the input member122and the output member121and make both members122and121enter a locked state or an unlocked state with each other, and a biasing member126that biases the rollers123in a direction giving the locked state. When the rotational speed of the positive direction (an arrow RD1direction) of the input member122receiving each rotational power from the first transmission TM1and the second transmission TM2exceeds the rotational speed of the positive direction of the output member121, the input member122and the output member121enter the locked state with each other, whereby the rotational power input to the input member122is transmitted to the output member121.

The first and second one-way clutches OWC1and OWC2are disposed in the left and the right sides with a differential device10interposed therebetween, and each output member121of the first and second one-way clutches OWC1and OWC2is connected to the driving target member11via separate clutch mechanisms CL1and CL2, respectively. The clutch mechanisms CL1and CL2are provided so as to control the transmission/disconnection of the power between each output member121of the first and second one-way clutches OWC1and OWC2and the driving target member11.

The driving target member11is configured by a differential case of the differential device10, and the rotational force transmitted to the output members121of the respective one-way clutches OWC1and OWC2is transmitted to the left and right driving wheels2via the differential device10and left and right accelerator shafts13L and13R. A differential pinion and a side gear (not shown) are attached to the differential case (the driving target member11) of the differential device10, the left and right accelerator shafts13L and13R are connected to the left and right side gears, and the left and right accelerator shafts13L and13R are subjected to a differential rotation.

In the first and second engines ENG1and ENG2, engines of high efficiency operation point different from each other are used, the first engine ENG1is an engine of a small displacement, and the second engine ENG2is an engine of the displacement greater than that of the first engine ENG1. For example, the displacement of the first engine ENG1is 500 cc, the displacement of the second engine ENG2is 1,000 cc, and the total displacement is 1,500 cc. Of course, the combination of the displacement is arbitrary.

The drive gear15attached to the output shaft of the main motor/generator MG1is engaged with the drive gear12provided in the driving target member11, whereby the main motor/generator MG1and the driving target member11are connected to each other in a power transmittable manner. For example, the main motor/generator MG1functions as the motor, the driving force is transmitted from the main motor/generator MG1to the driving target member11. When causing the main motor/generator MG1to function as the generator, the power is input from the driving target member11to the main motor/generator MG1, and the mechanical energy is converted to the electric energy. Simultaneously, the regeneration braking power acts on the driving target member11from the main motor/generator MG1.

The sub motor/generator MG2is directly connected to the output shaft S1of the first engine ENG1, and performs the mutual transmission of the power between the sub motor/generator MG2and the output shaft S1. Even in this case, when the sub motor/generator MG2functions as the motor, the driving force is transmitted from the sub motor/generator MG2to the output shaft S1of the first engine ENG1. When the sub motor/generator MG2functions as the generator, the power is transmitted from the output shaft S1of the first engine ENG1to the sub motor/generator MG2.

In the driving system1including the above elements, the rotational power generated in the first engine ENG1and the second engine ENG2is input to the first one-way clutches OWC1and the second one-way clutch OWC2via the first transmission TM1and the second transmission TM2, and the rotational power is input to the driving target member11via the first one-way clutches OWC1and the second one-way clutch OWC2.

In the driving system1, between the output shaft S2of the second engine ENG2and the driving target member11, a synchronization mechanism (clutch, starter clutch)20is provided which can connect and disconnect the power transmission between the output shaft S2and the driving target member11different from the power transmission via the second transmission TM2. The synchronization mechanism20includes a first gear21that is always engaged with the drive gear12provided in the driving target member11and is provided around the output shaft S2of the second engine ENG2in a rotatable manner; a second gear22that is provided so as to rotate integrally with the output shaft S2around the output shaft S2of the second engine ENG2; and a sleeve24that joins or releases the first gear21and the second gear22by being subjected to the slide operation in the axial direction. That is, the synchronization mechanism20configures a power transmission path different from the power transmission path via the second transmission TM2and the clutch mechanism CL2, and connects and disconnects the power transmission in the power transmission path.

Configuration of Transmission

Next, the first and second transmissions TM1and TM2used in the driving system1will be described.

The first and second transmissions TM1and TN2are configured by the continuously variable transmission mechanism of approximately the same configuration. This continuously variable transmission mechanism is a kind of a mechanism called IVT (Infinity Variable Transmission=a transmission mechanism of a type that sets the transmission ratio to infinity without using the clutch and can set the output rotation number to zero), is able to change the transmission ratio (ratio=i) in a non-step manner and can set the maximum value of the transmission ratio to infinity (∞). The continuously variable transmission mechanism is configured by the infinite continuously variable transmission mechanism BD (BD1and BD2).

As shown inFIGS. 2 and 3, the infinite continuously variable transmission mechanism BD includes an input shaft101that rotates around the input center axis O1by receiving the rotational power from the engines ENG1and ENG2, plural eccentric disks104that rotate integrally with the input shaft101, connection members130of the same number as that of the eccentric disks104for connecting the input shaft with the output shaft, and a one-way clutch120that is provided in the output side.

The eccentric disks104are formed in a circular shape around the first fulcrums O3, respectively. The first fulcrums O3are provided in a circumferential direction of the input shaft101at equal intervals, is able to change the eccentricity r1with respect to the input center axis O1, respectively, and are set so as to rotate with the input shaft101around the input center axis O1while maintaining the eccentricity r1. Thus, the eccentric disks104are provided so as to eccentrically rotate around the input center axis O1along with the rotation of the input shaft101in the state of maintaining the eccentricity r1, respectively.

As shown inFIG. 3, the eccentric disks104are configured by an outer peripheral side disk105, and an inner peripheral side disk108formed integrally with the input shaft101. The inner peripheral side disk108is formed as a thick disk in which the center thereof is biased to the input center axis O1, which is the center axis of the input shaft101, by a certain eccentric distance. The outer peripheral side disk105is formed as a thick disk around the first fulcrum O3, and has a first circular hole106having a center deviated from the center (the first fulcrum O3). The outer periphery of the inner peripheral side disk108is rotatably fitted into the inner periphery of the first circular hole106.

In the inner peripheral side disk108, a second circular hole109is provided which sets the input center axis O1as a center, a part of a circumferential direction thereof is opened to the outer periphery of the inner peripheral side disk108, and the pinion110is accommodated in the inner portion of the second circular hole109in a rotatable manner. The teeth of the pinion110is engaged with the inner toothed hear107formed in the inner periphery of the first circular hole106of the outer peripheral side disk1056through the opening of the outer periphery of the second circular hole109.

The pinion110is provided so as to rotate concentrically with the input center axis O1that is the center axis of the input shaft101. That is, the rotation center of the pinion110coincides with the input center axis O1that is the center axis of the input shaft101. As shown inFIG. 2, the pinion110rotates in the inner portion of the second circular hole109by an actuator180configured by a direct current motor and a deceleration mechanism. During normal times, the pinion110rotates in synchronicity with the rotation of the input shaft101, and by giving the pinion110the rotation number exceeding or falling below the rotation number of the input shaft101based on the rotation number of the synchronization, the pinion110rotates relatively to the input shaft101. For example, when the output shafts of the pinion110and the actuator180are disposed so as to be connected to each other and a rotation difference of the rotation of the actuator180is generated to the rotation of the input shaft101, it is possible to be realized by the use of a deceleration mechanism (e.g., a planetary gear) in which a relative angle between the input shaft101and the pinion110is changed by applying the deceleration ratio to the rotation difference. At this time, when the actuator180is synchronized with the input shaft101without the rotation difference therebetween, the eccentricity r1is not changed.

Thus, by rotating the pinion110, an inner teeth gear107with which the pinion110is engaged, that is, the outer peripheral side disk105rotates relatively to the inner peripheral side disk108, whereby a distance (that is, the eccentricity r1of the eccentric disk104) between the center (input center axis O1) of the pinion110and the center (the first fulcrum O3) of the outer peripheral side disk105is changed.

In this case, it is set so that the center (the first fulcrum O3) of the outer peripheral side disk105coincides with the center (the input center axis O1) of the pinion110by the rotation of the pinion110, and the eccentricity r1of the eccentric disk104can be set to “zero” by causing both centers to coincide with each other.

The one-way clutch120has an output member (an inner clutch)121that rotates around the output center axis O2separated from the input center axis O1; a ring-shaped input member (an outer clutch)122that is oscillated around the output center axis O2by receiving the power of the rotational direction from the outside; plural rollers (engagement members)123that are inserted between the input member122and the output member121so as to cause the input member122and the output member121to enter the locked state or the unlocked state with each other; and a biasing member126that biases the roller123in a direction giving the locked state. When the rotational power of the positive direction (e.g., a direction shown by an arrow RD1inFIG. 3) of the input member122exceeds the rotational speed of the positive direction of the output member121, the one-way clutch120transmits the rotational power input to the input member122to the output member121, whereby the oscillation movement of the input member122can be converted to the rotation movement of the output member121.

As shown inFIG. 2, the output member121of the one-way clutch120is configured as a member integrally connected in the axial direction, but the input members122are divided into plural members in the axial direction and are arranged so that the members can be independently oscillated in the axial direction, respectively. The roller123is inserted between the input member122and the output member121per each input member122by the number of the eccentric disk104and the connection member130a.

An overhang member124is provided in a place of the circumferential direction on each ring-shaped input member122, and a second fulcrum O4separated from the output center axis O2is provided in the overhang member124. A pin125is disposed on the second fulcrum O4of each input member122, and a tip (the other end portion)132of the connection member130is rotatably connected to the input member122by the pin125.

The connection member130has a ring portion131in one end side thereof, and an inner periphery of a circular opening133of the ring portion131is rotatably fitted into the outer periphery of the eccentric disk104via the bearing140. Thus, in this manner, the one end of the connection member130is rotatably connected to the outer periphery of the eccentric disk104, and the other end of the connection member130is rotatably connected to the second fulcrum O4provided on the input member122of the one-way clutch120, whereby a four bar linkage mechanism is configured which forms four bars of the input center axis O1, the first fulcrum O3, the output center axis O2, and the second fulcrum O4as rotation points, the rotational movement to be given from the input shaft101to the eccentric disk104is transmitted to the input member122of the one-way clutch120as the oscillation movement of the input member122, and the oscillation movement of the input member122is converted to the rotational movement of the output member121.

At that time, by moving the pinion110of the transmission ratio variable mechanism112, which is configured by the pinion110, the inner peripheral side disk108including the second circular hole109accommodating the pinion110, the outer peripheral side disk105including the first circular hole106rotatably accommodating the inner peripheral side disk108, the actuator180or the like, by the actuator180, the eccentricity r1of the eccentric disk104can be changed. By changing the eccentricity r1, the oscillation angle θ2of the input member122of the one-way clutch120, whereby it is possible to change the ratio (transmission ratio: ratio i) of the rotation number of the output member121with respect to the rotation number of the input shaft101. That is, by adjusting the eccentricity r1of the first fulcrum O3with respect to the input center axis O1, the oscillation angle θ2of the oscillation movement to be transmitted from the eccentric disk104to the input member122of the one-way clutch120is changed, whereby it is possible to change the transmission ratio when the rotational movement to be input to the input shaft101is transmitted to the output member121of the one-way clutch120via the eccentric disk104and the connection member130as the rotational power.

In this case, the output shafts S1and S2of the first and second engines ENG1and ENG2are integrally connected to the input shaft101of the infinite continuously variable transmission mechanism BD (BD1and BD2). The one-way clutch120as a component of the infinite continuously variable transmission mechanism BD (BD1and BD2) also functions as the first one-way clutch OWC1and the second one-way clutch OWC2provided between the first transmission M1and the second transmission TM2and the driving target member11, respectively.

FIGS. 4 and 5show a transmission principal by the transmission ratio variable mechanism112in the infinite continuously variable transmission mechanism BD (BD1and BD2). As shown inFIGS. 4 and 5, by rotating the pinion110of the transmission ratio variable mechanism112to rotate the outer peripheral side disk105with respect to the inner peripheral side disk108, it is possible to control the eccentricity r1with respect to the input center axis O1(the rotation center of the pinion110) of the eccentric disk104.

For example, as shown inFIGS. 4A and 5A, when the eccentricity r1of the eccentric disk104is “large”, the oscillation angle θ2of the input member122of the one-way clutch120can be increased, and thus the small transmission ratio i can be realized. As shown inFIGS. 4B and 5B, when the eccentricity r1of the eccentric disk104is “middle”, the oscillation angle θ2of the input member122of the one-way clutch120can be set to the “middle”, and thus the middle transmission ratio i can be realized. As shown inFIGS. 4C and 5C, when the eccentricity r1of the eccentric disk104is “small”, the oscillation angle θ2of the input member122of the one-way clutch120can be decreased, and thus the large transmission ratio i can be realized. As shown inFIG. 4D, when the eccentricity r1of the eccentric disk104is “zero”, the oscillation angle θ2of the input member122of the one-way clutch120can be set to “zero”, and thus the transmission ratio i can be set to “infinity (∞)”.

FIG. 6shows a driving force transmission principal of the infinite continuously variable transmission mechanism BD (BD1and BD2) configured as four bar linkage mechanism.FIG. 7shows a relationship between a rotation angle (θ) of an input shaft101and a rotation angle ω2of the input member122of the one-way clutch120when changing the eccentricity r1(a transmission ratio i) of the eccentric disk104, which rotates with the input shaft101at a constant velocity, to “large”, “middle”, and “small”, in the infinite continuously variable transmission mechanism BD (BD1and BD2).FIG. 8shows an extraction principal of the output when power is transmitted from the input side (the input shaft101or the eccentric disk104) to the output side (the output member121of the one-way clutch120) by plural connection members130in the infinite continuously variable transmission mechanism BD (BD1and BD2).

As shown inFIG. 6, the input member122of the one-way clutch120performs the oscillation movement by the power to be given from the eccentric disk104via the connection member130. When the input shaft101rotating the eccentric disk104rotates once, the input member122of the one-way clutch120reciprocally oscillates once. As shown inFIG. 7, the oscillation period of the input member122of the one-way clutch120is always constant regardless of the value of the eccentricity r1of the eccentric disk104. The angular speed ω2of the input member122is determined by the rotational angular speed ω1and the eccentricity r1of the eccentric disk104(the input shaft101).

One end (the ring portion131) of the connection members130connecting the input shaft101and the one-way clutch120is rotatably connected to the eccentric disk104provided around the input center axis O1in the circumferential direction at equal distances. Thus, as shown inFIG. 8, the oscillation movement generated in the input member122of the one-way clutch120by the rotation movement of the eccentric disk104is sequentially generated in a certain phase.

At that time, the transfer of the power (torque) from the input member122to the output member121of the one-way clutch120is performed only by the condition in which the rotational speed of the positive direction (an arrow RD1direction inFIG. 3) of the input member122exceeds the rotational speed of the positive direction of the output member121. That is, in the one-way clutch120, when the rotational speed of the input member122is higher than the rotational speed of the output member121, an engagement (lock) is initially generated via the roller123, and the power of the input member122is transmitted to the output member121by the connection member130, whereby the driving force is generated.

After the driving due to the one connection member130is finished, the rotational speed of the input member122is lowered further than the rotational speed of the output member121, and the locking due to the roller123is released by the driving force of the other connection member130, thereby returning to the free state (the operation state). This is sequentially performed by a number of the connection members130, the oscillation movement is converted to the rotational movement of the one direction. For that reason, only the power of the input member122of the timing exceeding the rotational speed of the output member121is sequentially transmitted to the output member121, and the substantially and smoothly regular rotational power is given to the output member121.

In the infinite continuously variable transmission mechanism BD (BD1and BD2) of the four bar linkage mechanism type, by changing the eccentricity r1of the eccentric disk104, the transmission ratio (ratio=the driving target member rotates by one rotation of the crank shaft of the engine) can be determined. In this case, by setting the eccentricity r1to zero, the transmission ratio i can be set to infinity, whereby the oscillation angle θ2to be transferred to the input member122can be set to zero without being restricted even during rotation of the engine.

Main Operation of Controller

Next, a control content executed in the driving system1will be described.

As shown inFIG. 1, the controller5controls various running patterns (also referred to as operation patterns) by sending the control signal to the first and second engines ENG1, ENG2, the main motor/generator MG1, the sub motor/generator MG2, the actuator180of the infinite continuously variable transmission mechanisms BD1and BD2constituting the first and second transmissions TM1and TM2, clutch mechanisms CL1and CL2, the synchronization mechanism20or the like to control the elements. Hereinafter, contents of a typical control will be described.

The controller5has a function of selecting and executing an EV running control mode that controls the EV running only by the driving force of the main motor/generator MG1, an engine running control mode that controls the engine running only by the driving force of the first engine ENG1and/or the second engine ENG2, and a series running control mode that drives the sub motor/generator MG2as a generator by the first engine ENG1, and controls the series running performing the mode running by the driving force of the main motor/generator MG1, while supplying the created electric power to the main motor/generator MG1and/or the battery8. The controller5also has a function of executing a series running mode running by the use of both the driving force of the main motor/generator MG1and the driving force of the first engine ENG1. The EV running, the series running, and the engine running are selected and executed depending on the residual capacity (SOC) of the required driving force and the battery8.

Herein, the series running is executed between the EV running and the engine running when switching over the running mode from the EV running to the engine running. During series running, by controlling the rotation number of the first engine ENG1and/or the transmission ratio of the first transmission TM1, the control is performed so that the rotational speed to be input into the input member122of the first one-way clutch OWC1is lower than the rotational speed of the output member121.

When switching over the running mode from the series running to the engine running, by controlling the rotation number of the first engine ENG1and the transmission ratio of the first transmission TM1, the rotational speed to be input to the input member122of the first one-way clutch OWC1is changed to the value exceeding the rotational speed of the output member121, whereby the running mode is shifted from the series running to the engine running.

When the first engine ENG1is started during EV running, in the state where the transmission ratio of the first transmission TM1is set so that the input rotation number of the first one-way clutch OWC1exceeds the output rotation number (in the state of mainly setting the transmission ratio to infinity so as to make the rotation load to a minimum), the first engine ENG1is started using the driving force of the sub motor/generator MG2. After switching over the running mode from the series running to the engine running, the electricity generation by the sub motor/generator MG2is stopped. However, after switching over the running mode from the series running mode to the engine running mode, when the residual capacity (SOC) of the battery8is equal to or less than a first predetermined value (a standard value: for example, standard SOCt=35%), the charge (the charging operation of the battery8by the electricity generation) by the sub motor/generator MG2is maintained.

Next, when performing the starting of the second engine ENG2, for example, as one method, the transmission ratio of the second transmission TM2is controlled to be transmitted to a limited value (a value closer to an objective value as much as possible) so that the power from the second engine ENG2can be transmitted to the second one-way clutch OWC2(i≠∞), and the rotational speed of the input member122of the second one-way clutch OWC2is lower than the rotational speed of the output member121. Otherwise, as another method, when starting the second engine ENG2, the control is performed so that the transmission ratio of the second transmission TM2is set to infinity (∞) and the rotational speed of the input member122of the second one-way clutch OWC2is lower than the rotational speed of the output member121. After starting the second engine ENG2, by changing the transmission ratio of the second transmission TM2to the limited value (the objective value), the rotational speed to be input to the second one-way clutch OWC2is controlled.

Herein, in the state of running by the use of the driving force of the first engine ENG1or the main motor/generator MG1, when starting the second engine ENG2by the use of the power of the driving target member11, by causing the synchronization mechanism20provided between the output shaft S2of the second engine ENG2and the driving target member11to enter the driving force transmittable connection state, the cranking (the start rotation) of the second engine ENG2is performed by the use of the power of the driving target member11, and the second engine ENG2is started.

When the second engine ENG2is started to switch over the driving source from the first engine ENG1to the second engine ENG2, in the state where the generated power of the first engine ENG1is input to the driving target member11via the first one-way clutch OWC1, the rotation number of the second engine ENG2and/or the transmission ratio of the second transmission TM2is changed so that the rotation number to be input to the input member122of the second one-way clutch OWC2exceeds the rotation number of the output member121. As a result, it is possible to smoothly switch over the engine used as the driving source from the first engine ENG1to the second engine ENG2.

When both the driving forces of the first engine ENG1and the second engine ENG2are synthesized and are transmitted to the driving target member11, a synchronization control is performed which controls the rotation number of the first and second engines ENG1and ENG2and/or the transmission ratio of the first and second transmissions TM1and TM2so that the rotational speeds to be input to both input members122of the first one-way clutch OWC1and the second one-way clutch OWC2are commonly synchronized to exceed the rotational speed of the output member121.

In this case, during acceleration, both the engines ENG1and ENG2are not unconditionally moved but are adapted to depend on the output request by raising the output of the other engine (the second engine ENG2) in the state of fixing one engine (the first engine ENG1) in a high efficiency operation point.

Specifically, when controlling the rotation number of the first and second engines ENG1and ENG2and/or the transmission ratio of the first and second transmissions TM1and TM2so that the rotational speeds to be input to the input members122of the first one-way clutch OWC1and the second one-way clutch OWC2exceed the rotational speed of the output member121, in the state of fixing the operation condition in a certain scope so that the rotation number and/or the torque of the first engine ENG1enters the high efficiency operation region, the first engine ENG1and/or the first transmission TM1is controlled, and controlling the second engine ENG2and the second transmission TM2copes with the output request exceeding the output to be obtained by the fixed operation condition.

As a control method different from the above method, depending on the request output, the second engine ENG2of a large displacement may be set in the fixing side of the operation condition, for example, when the request output is equal to or greater than a predetermined value, the first engine ENG1is set to the fixing side of the operation condition, and when the request output is equal to or less than a predetermined value, the second engine ENG2may be set in the fixing side of the operation condition.

During the backward movement of a vehicle, the clutch mechanisms CL1and CL2enter the disconnection state, whereby the state of not being able to make the backward movement through the locking of the first and second transmissions TM1and TM2is released. Meanwhile, during climbing departure, at least one of the clutch mechanisms CL1and CL2enters the connection state.

Operation Pattern

Next, an operation pattern of executing the driving system of the embodiment will be described.

FIGS. 9 to 23enlargedly show the extraction of the operation patterns A to O.FIGS. 24 to 33show a control operation that is executed depending on each operation state or a control operation during running mode switch-over. Reference numerals of A to O of a right upper portion of the frame showing each operation pattern ofFIGS. 24 to 33correspond to the reference numerals of the operation patterns A to O extracted and shown inFIGS. 9 to 23. In the drawings showing the operation patterns, the driving source during operation is distinguished and shown by the shading, and the transmission path of the power or the flow of the electric power are shown by arrows of solid lines, dashed lines or the like.

In the operation pattern A shown inFIG. 9, the EV running is performed by the driving force of the main motor/generator MG1. That is, the main motor/generator MG1is driven by conducting the electricity from the battery8to the main motor/generator MG1, the driving force of the main motor/generator MG1is transmitted to the driving target member11via the drive gear15and the driven gear12, and is transmitted to the driving wheel2via the differential device10and the left and right accelerator shafts13L and13R to perform the running. At this time, the clutch mechanisms CL1and CL2are in the disconnection state (OFF state).

In the operation pattern B shown inFIG. 10, the sub motor/generator MG generates the electricity using the driving force of the first engine ENG1, the generated electric power is supplied to the main motor/generator MG1and the battery8, thereby performing the series running. The starting of the first engine ENG1is performed by the sub motor/generator MG2. At this time, the transmission ratio of the first transmission TM1is set in infinity.

In the operation pattern C shown inFIG. 11, the parallel running is performed by the use of the driving forces of both the main motor/generator MG1and the first engine ENG1. In transmitting the driving force of the first engine ENG1to the driving target member11, the rotation number of the first engine ENG1and/or the transmission ratio of the first transmission TM1is controlled so that the input rotation number of the first one-way clutch OWC1exceeds the output rotation number. As a result, the synthetic force of the driving force of the main motor/generator MG1and the driving force of the first engine ENG1can be transmitted to the driving target member11. The operation pattern C is executed when the request driving force during acceleration or the like is great in the low speed running or the middle speed running. At this time, the clutch mechanism CL1is maintained in the connection state, and the clutch mechanism CL2is maintained in the disconnection state. As a result, the driving force of the first engine ENG1is transmitted to the driving target member11, and the dragging of the second one-way clutch OWC2is prevented.

The operation pattern D shown inFIG. 12is a departure pattern when SOC is low, in the state of performing the engine running by the use of the driving force of the first engine ENG1.

In the operation pattern E shown inFIG. 13, by the regeneration operation of the main motor/generator MG1that uses the power to be transmitted from the driving wheel2via the driving target member11during deceleration, the main motor/generator MG1is acted as the generator, the mechanical energy to be input from the driving wheel2via the driving target member11is changed to the electric energy. The regeneration braking force is transmitted to the driving wheel2, and the regeneration electric power is charged to the battery8. At this time, the clutch mechanisms CL1and CL2are disconnected.

In the operation pattern F shown inFIG. 14, the engine running is performed using only the driving force of the first engine ENG1, simultaneously, the sub motor/generator MG2generates the electricity using the driving force of the first engine ENG1, and the created electric power is charged to the battery8. The electricity generation of the sub motor/generator MG2may be stopped depending on SOC.

In the operation pattern G shown inFIG. 15, the second engine ENG2is started by the power introduced into the driving target member11(differential case) via the synchronization mechanism (starter clutch)20while running by the driving force of the first engine ENG1, and the insufficiency of the output to the driving wheel2due to the increase in load during starting is compensated by the driving force of the main motor/generator MG1. The sub motor/generator MG2generates the electricity using the driving force of the first engine ENG1, and the created electric power is supplied to the main motor/generator MG1or charged to the battery8.

In the operation pattern H shown inFIG. 16, the engine running is performed using the driving force of the first engine ENG1, and by disconnecting (or releasing the engagement state) the connected synchronization mechanism20in the operation pattern G, the driving target member11(differential case) and the output shaft S2of the second engine ENG2enter the separated state. In this state, the power of the second engine ENG2after the starting is input to the second transmission TM2. However, in the step, the input rotation number of the second one-way clutch OWC2does not exceed the output rotation number, and thus, the output of the second transmission TM2is not input to the driving target member11. The sub motor/generator MG2generates the electricity using the driving force of the first engine ENG1, and charges the created electric power to the battery8.

In the operation pattern I shown inFIG. 17, the engine running due to the driving force of the second engine ENG2is performed. The operation pattern I changes the transmission ratio of the second transmission TM2from the state of the operation pattern H to the OD side (overdrive), performs the control so that the rotation number of the input member122of the second one-way clutch OWC2exceeds the rotation number of the output member121, whereby the power of the second engine ENG2is transmitted to the driving target member11(differential case) via the second transmission TM2, thereby realizing the engine running due to the driving force of the second engine ENG2. In the operation pattern I, in the step in which the engagement by the second engine ENG2is established (the power transmission to the driving target member11is established), the first engine ENG1is stopped. At this time, the clutch mechanism CL2is maintained in the connection state, and the clutch mechanism CL1is maintained in the disconnection state. As a result, the driving force of the second engine ENG2is transmitted to the driving target member11, and the dragging of the one-way clutch OWC1is prevented.

The operation pattern J shown inFIG. 18is an operation pattern when the request output is further increased in the state of performing the engine running using the driving force of the second engine ENG2. In the operation pattern J, in the running state by the second engine ENG2, the first engine ENG1is started, the driving forces of both the first engine ENG1and the second engine ENG2are synthesized, and are transmitted to the driving target member11(the differential case). That is, the rotation number of the first and second engines ENG1and ENG2and/or the transmission ratios of the first and second transmissions TM1and TM2are controlled such that the rotation number of the input members122of the first and second one-way clutches OWC1and OWC2are synchronized to exceed the rotation number (the rotation number of the driving target member11) of the output member121.

The operation pattern K shown inFIG. 19is, for example, an operation pattern when the deceleration request is generated during middle speed running. In the operation pattern K, the first engine ENG1and the second engine ENG2are stopped, the main motor/generator MG1performs the electricity generation by the power to be transmitted from the driving wheel2via the driving target member11along with the deceleration, the regeneration electric power thus created is charged to the battery8, and the regeneration power is caused to act on the driving wheel2. Simultaneously, the synchronization mechanism20enters the connection state, and the engine brake of the second engine ENG2is caused to act on the driving wheel2as the braking force.

The operation pattern L shown inFIG. 20is an operation pattern during switch-over when the request output is increased in the state of running by the driving force of the second engine ENG2. In the operation pattern L, in order to start the first engine ENG1, the sub motor/generator MG2is driven. At this time, the transmission ratio of the first transmission TM1is set to infinity. After the first engine ENG1is started by the operation pattern, the operation pattern J is performed in which the driving forces of both the first and second engines ENG1and ENG2are transmitted to the driving target member11.

In the operation pattern M shown inFIG. 21, the synchronization mechanism20enters the connection state and enters the state where the engine brake by the second engine ENG2can be used, the sub motor/generator MG2generates the electricity using the driving force of the first engine ENG1, and the crated electric power is charged to the battery8.

In the operation pattern N shown inFIG. 22, the synchronization mechanism20enters the connection state and enters the state where the engine brake by the second engine ENG2can be used, and the regeneration electric power is created in the main motor/generator MG1and is charged to the battery8. At the same time, the sub motor/generator MG2generates the electricity using the driving force of the first engine ENG1, and the created electric power is charged to the battery8. By maintaining the synchronization mechanism20in the connection state, the second engine ENG2is in the state of the cranking standby.

The operation pattern O shown inFIG. 23is an operation pattern during stop, and in the operation pattern O, the sub motor/generator MG2generates the electricity using the driving force of the first engine ENG1, and the created electric power is charged to the battery8. At this time, by setting the transmission ratios of the first and second transmissions TM1and TM2to infinity (∞) or disconnecting the clutches CL1and CL2, the drag torque loss can be suppressed.

Control Operation Depending on Operation Situation

Next, control operations in various operation situations will be described usingFIGS. 24 to 33. The various operation situations are shown in a table form, and in the left lower portion of each frame in the table, for convenience of the description, reference numerals corresponding to the numbers in parentheses are given. Reference numerals A to O of the right upper portion of each frame correspond to the enlarged views ofFIGS. 9 to 23, and are referred to as necessary.

During Departure

Firstly, the control operation during departure will be described with reference toFIG. 24.

(1) At the time of the gradual cruise acceleration during departure, the EV running by the basic operation pattern A is performed. In the EV running, the main motor/generator MG1is driven by the electric power to be supplied from the battery8, and the running is performed only by the driving force.

(2) During acceleration, the series running by the operation pattern B is performed. In the series running, firstly, the first engine ENG1is started by the sub motor/generator MG2. When the second engine ENG2is started, the sub motor/generator MG2functions as the generator to generate the electricity, and the created electric power is supplied to the battery8and the main motor/generator MG1, whereby the electric power generated in the sub motor/generator MG2by the power of the first engine ENG1is effectively used while continuing the EV running. At this time, the rotation number of the first engine ENG1and/or the transmission ratio of the first transmission TM1are controlled so that the input rotation number of the first one-way clutch OWC1is lower than the output rotation number.

(3) When the rotation number of the first engine ENG1by the control is increased depending on the acceleration request, the transmission ratio of the first transmission TM1is changed so that the input rotation number of the first one-way clutch OWC1exceeds the output rotation number, and the parallel running is performed in which the driving forces of both the main motor/generator MG1and the first engine ENG1are synthesized. When SOC is low, the sub motor/generator MG2may be used as the generator to perform the charging of the battery8.

(4) When SOC is low, the departure is performed by the engine running by the first engine ENG1shown in the operation pattern D. Even in this case, the sub motor/generator MG2may be used as the generator to perform the charge of the battery8.

In this manner, during vehicle departure, the EV running mode using the driving force of the main motor/generator MG1, the series running mode using the first engine ENG1, the sub motor/generator MG2and the main motor/generator MG1, the parallel running mode using the driving forces of both the main motor/generator MG1and the first engine ENG1, and the engine running mode by the first engine ENG1are selected and executed depending on the operation situation.

During Low Speed Running (e.g., 0 to 30 km/h)

Next, the control operation during low speed running will be described with reference toFIG. 25.

(5), (6) During gradual cruise acceleration or during gradual cruise deceleration when, for example, the accelerator is separated, the EV running by the operation pattern A is performed.

(7) During deceleration when the brake is stepped, the regeneration operation by the operation pattern E is performed.

(8), (9) Even during gradual cruise deceleration and during gradual cruise acceleration, when the residual capacity (SOC) of the battery8is equal to or less than 35%, the series operation by the operation pattern B is performed.

(10) Even in the case of the acceleration, the series operation by the operation pattern B is performed.

(11) When the acceleration request is high, by the switch-over to the operation pattern C, the parallel running using the driving forces of the main motor/generator MG1and the first engine ENG1is performed.

Switch-Over of Driving Source from Main Motor/Generator MG1to First Engine ENG1

When the driving sources is switched over from the main motor/generator MG1to the first engine ENG1, the operation is controlled as shown inFIG. 26.

(12), (13) Firstly, from the situation in which the EV running by the operation pattern A is performed, the first engine ENG1is started by the sub motor/generator MG2. At that time, the transmission ratio of the first transmission TM1is set to infinity, and the output of the first engine ENG1does not enter the driving target member11. After the starting, the switch-over to the operation pattern B is performed, and the series running by the electricity generation of the sub motor/generator MG2is performed.

(14) Next, the transition to the operation pattern F is performed, the rotation number of the first one-way clutch OWC1and/or the transmission ratio of the first transmission TM1are controlled so that the input rotation number of the first one-way clutch OWC1exceeds the output rotation number, and the power of the first engine ENG1is transmitted to the driving target member11. For example, after setting the transmission ratio to infinity to enter the charge mode once, the transmission ratio is moved to OD (over drive) side, and the transition from the EV running by the main motor/generator MG1to the engine running by the first engine ENG1via the series running is smoothly performed. At this time, the clutch mechanism CL1is subjected to the connection control at a suitable time so that the delay is not generated.

When the power transmission (the switch-over of the driving source) to the driving target member11by the first engine ENG1is established, the main motor/generator MG1is stopped. However, when the battery residual capacity (SOC) is small, the electricity generation and the charging by the sub motor/generator MG2are continue, and when the battery residual capacity (SOC) is sufficient, the sub motor/generator MG2is stopped.

During Middle Speed Running (e.g., 20 to 70 km/h)

Next, the control operation during middle speed running will be described with reference toFIG. 27.

(15) During gradual cruise acceleration, by the operation pattern F, the single engine running is performed using only the driving force of the first engine ENG1. At that time, the battery8is charged by the electric power generated in the sub motor/generator MG2. The first engine ENG1is operated in the high efficiency operation point, and the control of the transmission ratio of the first transmission TM1copes with the operation situation.

(16), (17) During gradual deceleration and during deceleration, by the operation pattern E, the first engine ENG1is stopped, the clutch mechanisms CL1and CL2are switched over, and the regeneration operation by the main motor/generator MG1is performed.

(18) Meanwhile, during acceleration, the switch-over to the operation pattern C is performed, the parallel operation using the driving forces of both the first engine ENG1and the main motor/generator MG1is performed. At this time, basically, the engine running by the first engine ENG1is performed, and the main motor/generator MG1assists the acceleration request. The control operation is selected when the change in transmission ratio of the first transmission TM1cannot cope with the acceleration request during middle speed running.

Switch-Over of Driving Source from First Engine ENG1to Second Engine ENG2

When performing the switch-over from the engine running using the driving force of the first engine ENG1to engine running using the second engine ENG2, the operation control is performed as shown inFIG. 28.

(19), (20) Firstly, in the state where engine runs by the first engine ENG1by the operation pattern F, the switch-over to the operation pattern G is performed, and the second engine ENG2is started. In this case, the synchronization mechanism20is in the connection state, and the output shaft S2of the second engine ENG2is cranked by the power of the driving target member11, whereby the second engine ENG2is started. At that time, the rotation drop of the driving target member11by the starting shock is supplemented by the main motor/generator MG1. That is, the starting of the second engine ENG2can be performed only by the driving from the first engine ENG1introduced into the driving target member11, but can be performed even by the use of the driving force of the main motor/generator MG1. At this time, the transmission ratio of the second transmission TM2may be set so that the input rotation number of the one-way clutch is lower than the output rotation number, may be set to infinity, and may be set to a value slightly smaller than the objective transmission ratio. When the driving force of the first engine ENG1is sufficient, the sub motor/generator MG2may generate the electricity to charge the battery8.

(21) After that, when the second engine ENG2is started, the switch-over to the operation pattern H is performed, the synchronization mechanism20is in the disconnection state, and the main motor/generator MG1is stopped. In this step, the power of the second engine ENG2is in the state of not entering in the driving target member11. Thus, the transmission ratio of the second transmission TM2is gradually changed to the OD side. At this time, the sub motor/generator MG2generates the electricity using the first engine ENG1to charge the battery8.

(22) The transmission ratio of the second transmission TM2is changed to the OD side, and the input rotation number of the second one-way clutch OWC2exceeds the output rotation number, whereby the switch-over to the operation pattern I is performed, and the driving force of the second engine ENG2is transmitted to the driving target member11via the second one-way clutch OWC2.

During Middle High Speed Running (50 to 110 km/h)

Next, the control operation during middle high speed running will be described based onFIG. 29.

(23) During gradual cruise acceleration, by the operation pattern I, the single engine running using the driving force of the second engine ENG2is executed.

(24) During acceleration, by the switch-over to an operation pattern J described later, the running using the driving force of both the second engine ENG2and the first engine ENG1is performed. When SOC is low, the sub motor/generator MG2may be used as the generator to charge the battery8.

(25) During gradual cruise deceleration, by the operation pattern E, the regeneration operation by the main motor/generator MG1is performed, and both the engines ENG1and ENG2are stopped. When returning from (25) to (23), the synchronization mechanism20is in the connection state, and the second engine ENG2is cranked.

(26) During deceleration, by the operation pattern K, the main motor/generator MG1is subjected to the regeneration operation, and simultaneously, the synchronization mechanism20is in the connection state, whereby the engine brake by the second engine ENG2is performed.

Switch-Over from Engine Running from Second Engine ENG2to Engine Running by Second Engine ENG2and First Engine ENG1

When the engine running using the driving force of the second engine ENG2is shifted to the engine running using the both driving forces of the first engine ENG1in addition to the second engine ENG2, the operation is controlled as shown inFIG. 30.

(27), (28) Firstly, by the operation pattern I, in the state where the single engine running is performed by the second engine ENG2, as shown in the operation pattern L, the first engine ENG1is started using the sub motor/generator MG2.

(29) After that, a shown in the operation pattern J, the rotation number of the first and second engines ENG1and ENG2and/or the transmission ratios of the first and second transmissions TM1and TM2are controlled so that the rotation number of the input members122of the first and second one-way clutches OWC1and OWC2are synchronized and exceed the rotation number (the rotation number of the driving target member11) of the output member121, and the transition to the engine running is performed in which both driving forces of the second engine ENG2and the first engine ENG1are synthesized.

During High Speed Running (100 to Vmax km/h)

Next, the control operation during high speed running will be described based onFIG. 31.

(30), (31) During gradual cruise acceleration and during acceleration, by the operation pattern J, the engine running using the synthetic force of the driving force of the second engine ENG2and the driving force of the first engine ENG1is performed. At this time, the first engine ENG1of small displacement is operated in the fixed operation condition in which the first engine ENG1and/or the first transmission TM1are controlled so that the rotation number or the torque enters the high efficiency operation region, and in regard to a further request output, the second engine ENG2of large displacement and/or the second transmission TM2are controlled. When SOC is low, the sub motor/generator MG2is used as the generator to charge the battery8.

(32) During gradual cruise deceleration, by the operation pattern M, the synchronization mechanism20is in the connection state, the engine brake of the second engine ENG2is performed. At this time, the first engine ENG1not contributing to the deceleration is used in the electricity generation operation of the sub motor/generator MG2to charge the battery8.

(33) During deceleration when stepping on the brake, the switch-over to the operation pattern N is performed, the synchronization mechanism20is in the connection state, whereby the engine brake of the second engine ENG2is performed. Simultaneously, by the regeneration operation of the main motor/generator MG1, a strong braking force is worked. The regeneration electric power created in the main motor/generator MG1is charged to the battery8. The first engine ENG1not contributing the deceleration is used in the electricity generation operation of the sub motor/generator MG2to charge the battery8.

During Backward Movement

Next, the control operation during the backward movement will be described based onFIG. 32.

(34) During backward movement, as the gradual cruise acceleration, the EV running is performed by the operation pattern A. When the backward movement is performed, in the first and second one-way clutches OWC1and OWC2, the output member121connected to the driving target member11rotates in an opposite direction (an arrow RD2direction inFIG. 3) with respect to the positive direction, and thus the input member122and the output member121are engaged with each other via the roller123. When the input member122is engaged with the output member121, the rotational force of the opposite direction of the output member121acts on the input member122. However, when the input center axis O1is situated on the extension line of the connection member130shown inFIG. 34Aand the input center axis O1and the second fulcrum O4reach the most separated position (or when the rotational direction of the opposite direction to the positive direction is the arrow RD1direction inFIG. 3, a position where the connection member130shown inFIG. 34Bpasses through the input center axis O1and the input center axis O1and the second fulcrum O4are closest to each other), the input member122is connected to the connection member130, whereby the oscillation movement of the input member122is restricted. Thus, the transmission of the movement of the further opposite direction is locked. Accordingly, even if the output member121rotates reversely, the first and second transmissions TM1and TM2constituted by the infinite continuously variable transmission mechanisms BD1and BD2are locked, whereby the state, in which the backward movement is impossible (reverse impossible state), is generated. Thus, the clutch mechanisms CL1and CL2are in the release state in advance to avoid the lock, the main motor/generator MG1rotates reversely in that state, whereby the vehicle is reversed.

(35) Even during the backward movement in the EV running, when the residual capacity SOC of the battery8is equal to or less than 35%, the switch-over to the series running of the operation pattern B is performed, and the main motor/generator MG1rotates reversely while charging the battery8.

During Stop

Next, the control operation during stop will be described based onFIG. 33.

(36) When idling during vehicle stop, the switch-over to the operation pattern O is performed, only the first engine ENG1is operated, for example, the transmission ratio of the first transmission TM1is set to infinity so that the driving force is not transmitted to the driving target member11, the sub motor/generator MG2generates the electricity, and the generated electric power is charged to the battery8.

(37) When the idling is stopped, the whole power source is stopped.

Although the control operation during normal running was described above, according to the driving system1, the following method is also possible:

As described above, when a vehicle is reversed, the input member121reversely rotates to the input member122, whereby the first and second transmissions TM1and TM2enter the locked state. Thus, the function of entering the locked state is used as a heel hold function (slip down prevention) during climbing departure. That is, when detecting the situation of performing the climbing departure by a member such as a sensor, at least one of the clutch mechanisms CL1and CL2is held in the connection state. Then, since any one of the transmissions TM1and TM2enter the locked state, the slip-down of the vehicle can be prevented (realizing the heel hold function). Thus, there is no need to perform another heel hold control.

Next, relationship between the vehicle speed during actual running or the rotation number of the engine or the motor/generator, the transmission ratio of the transmission, and the battery residual capacity (SOC) will be described usingFIGS. 35 to 37. In the drawings, the vehicle speed is proportional to the rotation number of the main motor/generator MG1. The rotation number of the first engine ENG1and the second engine ENG2coincide to each other.

Running Pattern of Low Speed Region (0 to V2km/h)

The operation situation when running in the low speed region (0 to V2km/h) will be described usingFIG. 35. The value of V2is, for example, 50 km/h.

Firstly, when departing, the EV running by the main motor/generator MG1is performed. From the vehicle speed zero to a predetermined speed (<V2), the EV running is performed only by the main motor/generator MG1. At this time, the first engine ENG1and the sub motor/generator MG2are stopped. The first infinite continuously variable transmission mechanism BD1constituting the first transmission TM1is set to infinity.

Next, during EV running, when the battery residual capacity (SOC) is decreased and lowered to a standard value (SOCt=for example, about 35%), the transition from the EV running to the series running is performed. In that step, firstly, the first engine ENG1by the sub motor/generator MG2is started, and the first engine ENG1is operated by the rotation number entering the high efficiency operation region. At this time, the ratio of the first infinite continuously variable transmission mechanism BD1is maintained in infinity.

Next, when the acceleration request is generated during series running, the rotation number of the main motor/generator MG1begins to up, after further reducing the ratio of the first infinite continuously variable transmission mechanism BD1in that situation, the engine rotation number is gradually raised, and the ratio is changed, whereby the driving force of the first engine ENG1is transmitted to the driving target member11, and the switch-over to the engine running by the first engine ENG1is performed. In this step, the main motor/generator MG1is stopped.

When the vehicle speed is V2(maximum value of low speed region), the first engine ENG1is operated at a high efficiency, the ratio of the first infinite continuously variable transmission mechanism BD1is set to the value corresponding thereto, and the cruise running (stable running of a small load) by the first engine ENG1is performed.

Next, when the deceleration request is generated by stepping on the brake or the like, the first engine ENG1is stopped, the ratio of the first infinite continuously variable transmission mechanism BD1is changed to infinity, and the main motor/generator MG1is subjected to the regeneration operation until the vehicle is stopped.

Running Pattern of Middle Speed Region (V1to V3km/h)

The operation situation when running in the middle speed region (V1to V3km/h) will be described usingFIG. 36. V1<V2<V3, the value of V1is, for example, 20 km/h, and the value of V3is, for example, 110 km/h.

Firstly, when there is an acceleration request from the vehicle speed V1, in an initial step, the rotation number of the main motor/generator MG1is up, and next, the engine rotation number of the first engine ENG1is raised and the ratio of the first infinite continuously variable transmission mechanism BD1is changed. The driving force of the first engine ENG1is transmitted to the driving target member11, and the switch-over from the series running by the first engine ENG1and the main motor/generator MG1to the engine running by the first engine ENG1is performed. In this step, the main motor/generator MG1is stopped.

When the vehicle speed is stable, the first engine ENG1is operated at a high efficiency, the ratio of the first infinite continuously variable transmission mechanism BD1is maintained in the value corresponding thereof, and the cruise running by the first engine ENG1is performed.

Next, when a further acceleration request is generated in the situation where the cruise running by the first engine ENG1is performed, the rotation number of the first engine ENG1is raised, and the ratio of the first infinite continuously variable transmission mechanism BD1is increased. Consecutively, the driving force of the first engine ENG1is transmitted to the driving target member11, the second engine ENG2is started in the state where the ratio of the second infinite continuously variable transmission mechanism BD2is set to infinity, the rotation number of the second engine ENG2is raised, the engagement is performed in the state where the ratio of the second infinite continuously variable transmission mechanism BD2is reduced, the ratio is gradually increased, and the driving force of the second engine ENG2is transmitted to the driving target member11. The engine running only by the driving force of the first engine ENG1is switched over to the engine running in which the driving forces of both the first engine ENG1and the second engine ENG2are synchronized, synthesized and transmitted to the driving target member11.

When the vehicle speed is V3(the maximum value of the middle speed region), the ratio of the first infinite continuously variable transmission mechanism BD1is set to infinity, the driving force of the first engine ENG1is not transmitted to the driving target member11, and the switch-over to the engine running only by the driving force of the second engine ENG2is performed. The second engine ENG2is operated at a high efficiency, the ratio of the second infinite continuously variable transmission mechanism BD2is set to the value corresponding thereto, and the cruise running by the second engine ENG2is performed. In an initial period of the engine running only by the second engine ENG2, the sub motor/generator MG2is driven by the first engine ENG1, and the generated electric power is charged to the battery8. At this time, the first engine ENG1is operated (series) in a high efficiency operation region, and then, when the battery8is charged up to a second predetermined value (e.g., SOCu=80%), the first engine ENG1is stopped.

Next, when the deceleration request is generated by stepping on the brake or the like, the ratio of the second infinite continuously variable transmission mechanism BD2is set to infinity, the main motor/generator MG1is subjected to the regeneration operation, and the engine brake by the second engine ENG2is performed. When the vehicle speed is dropped, the first engine ENG1is started, the rotation number thereof is raised, and the ratio of the first infinite continuously variable transmission mechanism BD1is changed, and the driving force of the first engine ENG1is transmitted to the driving target member11. The switch-over to the engine running using the driving force of the first engine ENG1is performed.

Running Pattern of High Speed Region (V2to V4km/h)

The operation situation when running in the high speed region (V2to V4km/h) will be described usingFIG. 37. V2<V3<V4, and the value of V4is, for example, 150 km/h.

Firstly, in the situation when the engine runs only by the driving force of the first engine ENG1, when there is an acceleration request, the engine rotation number of the first engine ENG1is raised, the ratio of the first infinite continuously variable transmission mechanism BD1is changed. Consecutively, the driving force of the first engine ENG1is transmitted to the driving target member11, the second engine ENG2is started in the state where the ratio of the second infinite continuously variable transmission mechanism BD2is set to infinity, the rotation number of the second engine ENG2is raised, the ratio of the second infinite continuously variable transmission mechanism BD2is gradually increased from the small state, and the driving force of the second engine ENG2is transmitted to the driving target member11. The engine running only by the driving force of the first engine ENG1is switched over to the engine running in which the driving forces of both the first engine ENG1and the second engine ENG2are synchronized, synthesized and transmitted to the driving target member11.

When the vehicle speed is stable, the ratio of the first infinite continuously variable transmission mechanism BD1is set to infinity, the driving force of the first engine ENG1is not transmitted to the driving target member11, and the switch-over to the engine running only by the driving force of the second engine ENG2is performed. The second engine ENG2is operated at a high efficiency, the ratio of the second infinite continuously variable transmission mechanism BD2is set to the value corresponding thereto, and the cruise running by the second engine ENG2is performed. In an initial period of the engine running only by the second engine ENG2, the sub motor/generator MG2is driven by the first engine ENG1, and the generated electric power is charged to the battery8. At this time, the first engine ENG1is operated at a high efficiency operation (series), and then, the first engine ENG1is stopped.

Next, when a further acceleration request is generated in the situation where the cruise by the second engine ENG2is performed, the rotation number of the second engine ENG2is raised, the ratio of the second infinite continuously variable transmission mechanism BD2is changed. Simultaneously, the first engine ENG1is started, the rotation number thereof is raised, the ratio of the first infinite continuously variable transmission mechanism BD1is changed, the driving force of the first engine ENG1and the driving force of the second engine ENG2are transmitted to the driving target member11, and the engine running only by the driving force of the second engine ENG2is switched over to the engine running in which the driving force of both the second engine ENG2and the first engine ENG1are synchronized, synthesized and transmitted to the driving target member11.

When the vehicle speed is V4(the maximum value of high speed region), preferentially, the first engine ENG1is operated at a high efficiency, the ratio of the first infinite continuously variable transmission mechanism BD1is set to the value corresponding thereto, the second engine ENG2and the first infinite continuously variable transmission mechanism BD1are set to the value suitable for the cruise running, and the cruise running (stable running of a small load) by the first and second engines ENG1and ENG2is performed.

Next, when the deceleration request is generated by stepping on the brake or the like, the ratio of the first infinite continuously variable transmission mechanism BD1is set to infinity, the first engine ENG1is stopped, and the main motor/generator MG1is subjected to the regeneration operation. Simultaneously, the engine brake by the second engine ENG2is performed. When the vehicle speed is dropped, the rotation number of the second engine ENG2and the ratio of the second infinite continuously variable transmission mechanism BD2are changed, the driving force of the second engine ENG2is transmitted to the driving target member11, and the switch-over to the engine running using only the driving force of the second engine ENG2is performed.

FIG. 38shows engagement setting ranges for the first and second engines ENG1and ENG2. The transverse axis thereof shows an engine rotation number, and the longitudinal axis thereof shows the ratio of the transmission mechanism.

For example, when starting the first engine ENG1in the state where the ratio is infinity (∞), the engine rotation number is raised to a predetermined value, the ratio is reduced from infinity (∞) in this state, otherwise, when the engine rotation number is increased, it reaches a vehicle speed line, and the engine output is transmitted to the driving target member11(the engagement is established). Even when the second engine ENG2is operated, the ratio is gradually decreased from infinity (∞) of a limited value slightly larger than an objective ratio to be engaged. Otherwise, the engine rotation number is increased. Then, by reaching the vehicle speed line, the engine output is transmitted to the driving target member11(the engagement is established). For this reason, it is possible to suitably set the rotation number of the respective engines ENG1and ENG2and the ratio of the transmission mechanism in the engage scope depending on the vehicle speed, whereby the high efficiency operation of the engine is possible. Thus, the first engine ENG1is operated in the high efficiency operation point, when a high request driving force is generated, the second engine ENG2can be operated while selecting the engine rotation number and the ratio, whereby it is also possible to use both engines EBG1and ENG2in the operation point of a satisfactory efficiency.

Next, advantages of the above-described driving system1will be described. The driving system1of the embodiment provides the below advantages.

Since the respective first and second engines ENG1and ENG2are individually equipped with the transmissions TM1and TM2as the transmission mechanisms, by the combination of the setting of the rotation number of the engines ENG1and ENG2and the transmission ratios of the transmissions TM1and TM2, it is possible to control the output rotation number (the input rotation number of the input members122of the first and second one-way clutches OWC1and OWC2) from the transmissions TM1and TM2. Thus, depending on the setting of the transmission ratios of the transmissions TM1and TM2, the rotation number of each engine ENG1and ENG2can be independently controlled, and each engine ENG1and ENG2can be operated in the operation point of the satisfactory efficiency, respectively, which can greatly contribute to improved fuel efficiency.

When a group of “the first engine ENG1and the first transmission TM1” and a group of “the second engine ENG2and the second transmission TM2” are referred to as “power mechanisms”, the power mechanisms of two groups are connected to the same the driving target member11via one-way clutches OWC1and OWC2, respectively. Thus, the selective switch-over of the power mechanism to be used as the power source or the synthesis of the driving forces from two power mechanisms can be executed only by controlling the input rotation number (the rotation number to be output from the power mechanism) with respect to the respective one-way clutches OWC1and OWC2.

As the first and second transmissions TM1and TM2, the infinite continuously variable transmission mechanisms BD1and BD2transmittable in a non-step manner, respectively are used. Thus, only by changing the transmission ratios of the infinite continuously variable transmission mechanisms BD1and BD2in a non-step manner, it is possible to smoothly control ON/OFF of the power transmission from each power mechanism to the driving target member11while maintaining the operation state in the high efficiency operation point, without changing the rotation number of the first and second engines ENG1and ENG2.

In this regard, in the case of a step transmission mechanism, in order to smoothly control ON/OFF of the one-way clutches OWC1and OWC2by changing the output rotation number of the power mechanism, there is a need to adjust the rotation number of the engines ENG1and ENG2to meet the transmission gear step. Meanwhile, in the case of the infinite continuously variable transmission mechanisms BD1and BD2, since the output rotation number of the power mechanism can be smoothly changed only by adjusting the transmission ratios of the infinite continuously variable transmission mechanisms BD1and BD2in a non-step manner without changing the rotation number of the engines ENG1and ENG2, it is possible to smoothly perform the switch-over of the driving source (the engines ENG1and ENG2) due to ON/OFF of the power transmission between the power mechanism and the driving target member11via the one-way clutches OWC1and OWC2. Thus, it is possible to keep the operation of the engines ENG1and ENG2in an operation state having a satisfactory BSFC (Brake Specific Fuel Consumption).

Especially, by adopting the infinite continuously variable transmission mechanisms BD1and BD2of the embodiment, the transmission ratio can be set to infinity only by changing the eccentricity r1of the eccentric disk104. Thus, by setting the transmission ratio to infinity, when the engines ENG1and ENG2are started or the like, the inertial mass portion of the downstream side can be substantially separated from the engines ENG1and the ENG2. For that reason, the inertial mass portion of the downstream side (the output side) does not amount to resistance of the starting of the engines ENG1and ENG2, but the starting of the engines ENG1and ENG2can be smoothly performed. In the case of this type of infinite continuously variable transmission mechanisms BD1and BD2, since the number of gears used can be reduced, energy loss due to engagement abrasion of the gears can be reduced.

Since the main motor/generator MG1is connected to the driving target member11as the power source different from the engines ENG1and ENG2, it is possible to perform the EV running using only the driving force of the main motor/generator MG1. During EV running, since the rotational speed of the positive direction of the output member121exceeds the rotational speed of the positive direction of the input member122in the first and second one-way clutches OWC1and OWC2, the state of clutch OFF (unlocked state) is generated, the power mechanism is separated from the driving target member11, and the rotational load can be reduced.

When shifting from the EV running to the engine running using the driving force of the first engine ENG1, the control is performed so that the input rotation number of the first one-way clutch OWC1annexed to the first engine ENG1using the driving force exceeds the rotation number of the driving target member11that is driven by the main motor/generator MG1. As a result, it is possible to easily switch over the running mode from the EV running to the engine running.

By synchronizing the rotation number to be input from the first engine ENG1to the first one-way clutch OWC1with the rotation number to be given from the main motor/generator MG1to the driving target member11, it is also possible to perform a parallel running which uses both the driving force of the first engine ENG1and the driving force of the main motor/generator MG1. Since it is also possible to start the second engine ENG2by the use of the driving force of the main motor/generator MG1, a separate starter device (e.g., a starter motor or the like) for the second engine ENG2can be omitted. By causing the main motor/generator MG1to function as a generator when a vehicle is decelerated, since it is possible to cause a regeneration braking force to act on the driving wheel2and charge the regeneration electric power to the battery8, an improvement in energy efficiency is also promoted.

Since the sub motor/generator MG2is connected to the output shaft S1of the first engine ENG1, the sub motor/generator MG2can be used as the starter of the first engine ENG1, and there is no need to provide a separate starter device for the first engine ENG1. By using the sub motor/generator MG2as a generator that generates electricity by the driving force of the first engine ENG1and supplying the generated electric power to the main motor/generator MG1, the series running can also be performed.

In this manner, as the power source different from the engines ENG1and ENG2, by equipping the main motor/generator MG1and the sub motor/generator MG2, besides the engine running using only the driving forces of the engines ENG1and ENG2, it is possible to select and execute various running modes such as the EV running that uses only the driving force of the main motor/generator MG1, the parallel running that uses the driving forces of both the engines ENG1and ENG2and the main motor/generator MG1, and the series running which supplies the electric power generated in the sub motor/generator MG2to the main motor/generator MG1using the driving force of the first engine ENG1and performs the running by the driving force of the main motor/generator MG1. By selecting an optimal running mode depending on the condition, it is possible to contribute to improved fuel efficiency.

During switch-over of the running modes, by using the infinite continuously variable transmission mechanisms BD1and BD2in the transmissions TM1and TM2, it is possible to smoothly switch-over the running mode from the EV running or the series running using the driving force of the main motor/generator MG1to the engine running using the driving force of the first engine ENG1without shock.

Herein, during series running executed between the EV running and the engine running, the rotation number of the first engine ENG1and/or the transmission ratio of the first transmission TM1are adjusted (that is, the power by the first engine ENG1is directly used as the running driving force) so that the input rotation number of the first one-way clutch OWC1exceeds output rotation number thereof, and the series running is realized. After that, in the step of the transition from the series running to the engine running, the rotation number of the first engine ENG1and/or the transmission ratio of the first transmission TM1are controlled so that the input rotation number of the first one-way clutch OWC1is lower than the output rotation number thereof, and the driving force of the first engine ENG1is input to the driving target member11. Thus, it is possible to promote the efficient utilization of the engine energy while shifting from the starting of the first engine ENG1to the engine running. That is, while the driving force is transmitted to the driving target member11after the engine is started, the engine energy is supplied to the main motor/generator MG1or the battery8as the electric power and used effectively by performing the series running. Thus, the generated energy can be used without waste, which can contribute to improved fuel efficiency.

Especially, when shifting from the EV running using only the driving force of the main motor/generator MG1to the series running, there is a need for the starting of the first engine ENG1in the EV running state. However, since the resistance during starting can be reduced by the adaptation of the first one-way clutch OWC1and by setting the transmission ratio of the first transmission TM1to infinity, it is possible to smoothly perform the transition from the EV running to the series running without shock. By substantially disconnecting the first engine ENG1from the inertial mass portion of the downstream side thereof by setting the transmission ratio of the first transmission TM1to infinity, the rotation resistance when executing the series running can be reduced, and thus, the energy loss during series running is greatly reduced, which can contribute to improved fuel efficiency.

The transmission ratio is set to infinity, even if the rotation number of the first engine ENG1is increased anyway, the power of the first engine ENG1is not transmitted to the driving target member11via the first one-way clutch OWC1, and thus, the series running can be stably maintained.

During series running, only by controlling the input rotation number of the first one-way clutch OWC1, even if the clutch is provided or a special control is performed, the power of the first engine ENG1is disconnected from the driving target member11, and the first engine ENG1can function as the power source of the exclusive purpose of the generator. Thus, the engine ENG1can be stably operated in the high efficiency point without requiring the control of the engine rotation number or the like depending on the running load, which can greatly contribute to improved fuel efficiency.

When shifting from the series running to the engine running, since the electricity generation by the sub motor/generator MG2is stopped, the burden of the first engine ENG1can be reduced. Even in the case of shifting from the series running to the engine running, when the battery residual capacity is small, the electricity generation by the sub motor/generator MG2is continued to perform the charging, whereby it is possible to promote the burden reduction of the first engine ENG1while suitably holding the charging state of the battery8.

Since the clutch mechanisms CL1and CL2are provided between the output member121of first and second one-way clutches OWC1and OWC2and the driving target member11, by causing the clutch mechanisms CL1and CL2to enter the disconnection state, it is possible to separate the power transmission path (from the engines ENG1and ENG2to one-way clutches OWC1and OWC2) of the upstream side from the clutch mechanisms CL1and CL2from the power transmission path (from the driving target member11to the driving wheel2) of the downstream side. Thus, when driving the driving target member11by one of the first and second engines ENG1and ENG2via one of the first and second one-way clutches OWC1and OWC2, by disconnecting one of the clutch mechanisms CL1and CL2provided between the other of the clutches OWC1and OWC2and the driving target member11, it is possible to prevent the dragging of the one-way clutches OWC1and OWC2not used in the wheel driving, whereby the unnecessary energy loss can be reduced.

When the input member122and the output member121of the one-way clutches OWC1and OWC2rotate in the opposite direction (a rotational direction during backward movement) with respect to the positive direction (the rotational direction when a normal vehicle is moved forward), the first and second transmissions TM1and TM2constituted by the above-described infinite continuously variable transmission mechanisms BD1and BD2functions to lock and prevent the reverse rotation of the driving target member11. For this reason, by maintaining the clutch mechanisms CL1and CL2in the release state, the upstream side of the clutch mechanisms CL1and CL2can be separated from the driving target member11, whereby it is possible to avoid the locking effect (also called backward movement prevention effect) by the transmissions M1and M2. Thus, it is possible to perform the backward movement rotation of the driving target member11by the reverse rotation operation of the main motor/generator MG1, whereby the vehicle can be moved reversing.

When departing in a climbing road, by maintaining the clutch mechanisms CL1and CL2in the connection state, it is possible to obtain the heel hold function (a function of not slipping down in a hill road) using the backward movement prevention effect by the locking of the transmissions TM1and TM2, and thus, another heel hold control is not necessary.

By setting the sizes of the displacements of the first and second engines ENG1and ENG2to be different from each other, the high efficiency operation points of both engines ENG1and ENG2can be different from each other. Thus, by selecting the engines ENG1and ENG2of the high efficiency side as the driving source depending on the running state, an overall improvement in energy efficiency can be promoted.

By the method of the setting of the input rotation number of two one-way clutches OWC1and OWC2, a smooth and easy switch-over from the running by one engine to the running by the other engine can be performed. For example, during engine control operation shown inFIG. 28(when switching over from the middle speed running to the middle high speed running), in the state of performing the engine running by inputting the driving force of the first engine ENG1to the driving target member11via the first one-way clutch OWC1, the rotation number of the second engine ENG2and/or the transmission ratio of the second transmission TM2are changed so that the rotation number to be input to the input member122of the second one-way clutch OWC2exceeds the rotation number of the output member121, whereby it is possible to easily switch over the driving source extracting the power to the driving target member11from the first engine ENG1to the second engine ENG2. The switch-over operation is only to control the rotation number, which is input to the first and second one-way clutches OWC1and OWC2via the infinite continuously variable transmission mechanisms BD1and BD2, and can be smoothly performed without shock.

As in the control operation shown inFIG. 28, by setting the transmission ratio of the second transmission TM2during starting of the second engine ENG2to infinity, the inertial mass portion of the downstream side of the second transmission TM2can be separated from the second engine ENG2. Thus, the resistance due to the inertial mass during starting of the second engine ENG2can be reduced, and the starting energy can be reduced. When the second engine ENG2is started while the driving force is switched over from the first engine ENG1to the second engine ENG2, the power cannot be transmitted from the second transmission TM2to the downstream side. Thus, even when the rotation number of the driving target member11is reduced by a certain cause (e.g., suddenly stepping on the brake or the like) during starting, the starting shock can be reduced. After the starting of the second engine ENG2, by changing the transmission ratio of the second transmission TM2to a limited value, the rotational speed to be input to the second one-way clutch OWC2is controlled. Thus, by raising the input rotational speed thereof until exceeding the rotational speed of the output member121, the power of the second engine ENG2can be reliably transmitted to the driving target member11.

As a method of the control during starting of the second engine ENG2, another control operation can also be adopted. That is, when the second engine ENG2is started, in the state of setting the second transmission TM2in the suitable transmission ratio (the transmission ratio when being larger than an objective transmission ratio, a limited value in which the rotational speed of the input member122of the second one-way clutch OWC2is lower than the rotational speed of the output member121) in advance, the second engine ENG2is started. In that case, it is possible to reduce the time from the starting to the setting of the objective transmission ratio (the transmission ratio in which the rotational speed of the input member122of the second one-way clutch OWC2exceeds the rotational speed of the output member121), and thus, an improvement in response depending on the request is promoted.

As in the control operation shown inFIG. 30in the control operation, by controlling the rotation number of the first and second engines ENG1and ENG2and/or the transmission ratios of the first and second transmissions TM1and TM2so that the rotational speed to be input to both input members122of the first one-way clutch OWC1and the second one-way clutch OWC2exceeds the rotational speed of the output member121, the great driving force, in which the outputs of two engines ENG1and ENG2are synthesized, can be easily input to the driving target member11, and it is possible to perform the engine running using the driving force of both the first engine ENG1and the second ENG2. At that time, in the transmissions TM1and TM2, by using the infinite continuously variable transmission mechanisms BD1and BD2, it is possible to smoothly perform the switch-over from the running using the driving force of one engine ENG2to the running using the synthetic driving force of two engines ENG1and ENG2without shock.

When starting the first engine ENG1during EV running, the first engine ENG1is started in the state of setting the transmission ratio of the first transmission TM1so that the input rotation number of the first one-way clutch OWC1does not exceed the output rotation number, that is, so that the driving force of the first engine ENG1is not transmitted to the driving target member11of the downstream side of the first transmission TM1. Thus, it is possible to prevent shock of engine starting from being transmitted to the driving wheel2. The load can also be reduced during engine starting, and the smooth starting is possible.

Since the first engine ENG1is started by the sub motor/generator MG2, there is no need to separately provide a starter device of the exclusive purpose of the first engine ENG1.

Since the driving target member11and the output shaft S2of the second engine ENG2are connected to each other via the synchronization mechanism20, by causing the synchronization mechanism20to enter the connection state in the state where the power is introduced into the driving target member11, it is possible to perform the start rotation of the output shaft S2of the second engine ENG2by the power of the driving target member11. Thus, there is no need to provide a starter device of the exclusive purpose of the second engine ENG2. During starting, the power necessary for the starting of the second engine ENG2may not be introduced into the driving target member11. Mainly, in many cases, since the power from the first engine ENG1as the driving source is input to the driving target member11, the power can be used. Like an operation called a so-called “pressing”, the power due to the coasting introduced from the driving wheel2side into the driving target member11.

Basically, the starting of the second engine ENG2is performed when supplying the power to the driving target member11by the first engine ENG1. However, even when the power is supplied to the driving target member11by the main motor/generator MG1, by causing the synchronization mechanism20to enter the connection state, it is possible to perform the cranking (giving the starter rotation to the engine also called motoring) of the second engine ENG2by the power to be transmitted from the main motor/generator MG1to the driving target member11. In the state of supplying the power to the driving target member11by the first engine ENG1, when starting the second engine ENG2, there is a possibility that the power of the driving target member11is insufficient (the rotation number is dropped) due to the division of the power into the cranking of the second engine ENG2, but the insufficiency can be supplemented by the driving force of the main motor/generator MG1. By doing so, fluctuation of the power of the driving target member11can be suppressed, it is possible to promote the reduction in shock to the driving wheel when the second engine ENG2is started. That is, it is possible to smoothly start the second engine ENG2without shock.

Immediately after the second engine ENG2is started, when the driving power of the second engine ENG2is immediately transmitted to the driving target member11via the second transmission TM2and the second one-way clutch OWC2, shock may be generated in the driving wheel2. However, when the second engine ENG2is cranked, by setting the transmission ratio so that the rotational speed of the input member122of the second one-way clutch OWC2is lower than the rotational speed of the output member121, immediately after the starting, the power from the second engine ENG2is not transmitted to the driving target member11, and thus shock generated in the driving wheel2can be suppressed. Especially, by setting the transmission ratio to infinity in the second infinite continuously variable transmission mechanism BD2, it is possible to separate the inertial mass of the inner portion or the downstream side thereof of the transmission mechanism BD2from the output shaft S2of the second engine ENG2as much as possible. Thus, the starting resistance of the second engine ENG2can be reduced, and the starting is easily performed.

When the driving forces of two engines ENG1and ENG2during high speed running or the like are synthesized to drive the driving target member11, at least one of the first engine ENG1is operated in the high efficiency operation region, which can contribute to improved fuel efficiency. That is, in the state of fixing the operation condition in a certain scope so that the rotation number of the first engine ENG1and/or the torque enter the high efficiency operation region, the first engine ENG1and/or the first transmission TM1are controlled, and controlling the second engine ENG2and the second transmission TM2can cope with the output request exceeding the output to be obtained by the fixed operation condition, which can contribute to improved fuel efficiency.

Particularly, even when the displacement of the first engine ENG1, to which the operation condition is fixed, is smaller than the displacement of the second engine ENG2, and the fluctuation in the request output is great, the engine of the large displacement copes with the request fluctuation, and thus, the delay to the request can be reduced. When the displacement of the first engine ENG1, to which the operation condition is fixed, is larger than the displacement of the second engine ENG2, the engine of the large displacement is operated in the high efficiency operation range, which can further contribute to improved fuel efficiency.

The control can be performed so that, when the request output is equal to or greater than a predetermined value, the engine of the small displacement is set in the operation condition fixing side, and when the request output is equal to or less than a predetermined value, the engine of the large displacement is set in the operation condition fixing. In that case, the delay to the request can be reduced, and improved fuel efficiency can be promoted.

The present invention is not limited to the above embodiment, but can be suitably modified or improved. Materials, shapes, sizes, numbers, disposition places or the like of the respective components in the above embodiments are arbitrary and not limited as long as they can accomplish the present invention.

For example, in the above embodiment, in the left and right sides of the differential device10, the first one-way clutch OWC1and the second one-way clutch OWC2are disposed, respectively, and the output members121of the respective first and second one-way clutches OWC1and OWC2are connected to the driving target member11via the clutch mechanisms CL1and CL2. However, as in another embodiment shown inFIG. 39, the first and second one-way clutches OWC1and OWC2may be disposed on one side of the differential device10, and the one-way clutches may be connected to the driving target member11via one clutch mechanism CL after connecting the output members of the both one-way clutches OWC1and OWC2.

In the above embodiment, the first and second transmissions TM1and TM2are configured by the type using the eccentric disk104or the connection member130and the one-way clutch120. However, other CVT or the like may be used as the transmission mechanism. When using the transmission mechanism of other type, the one-way clutches OWC1and OWC2may be provided in the outside (the downstream side) of the transmission mechanism.

In the above embodiment, a case was described where the state running by the driving force of the first engine ENG1is switched over to the state running by the driving force of the second engine ENG2. However, contrary to this, the state running by the driving force of the second engine ENG2is switched over to the state running by the driving force of the first engine ENG1. In that case, in the state where the generated power of the second engine ENG2via the second one-way clutch OWC2is input to the driving target member11, by changing the rotation number of the first engine ENG1and/or the transmission ratio of the first transmission TM1so that the rotation number to be input to the input member122of the first one-way clutch OWC1exceeds the rotation number of the output member121, the switch-over can be smoothly performed.

In the above embodiment, a configuration was described which has two engines and two transmissions, but a configuration having three or more engines and three or more transmissions may be used. The engine may be used by combining a diesel engine or a hydrogen engine and a gasoline engine.

The first engine ENG1and the second engine ENG2of the above embodiment may be configured as a separated body or may be configured as one body. For example, as shown inFIG. 40, the first engine ENG1and the second engine ENG2may be disposed in the common block BL as the first internal combustion engine section and the second internal combustion engine section, respectively of the present invention.

The present invention is based on Japanese Patent Application No. 2010-136542 filed on Jun. 15, 2010, Japanese Patent Application No. 2010-136544 filed on Jun. 15, 2010, and Japanese Patent Application No. 2010-136549 filed on Jun. 15, 2010, and the contents thereof are incorporated herein by reference.

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