Abstract: Systems and methods for improving operation of a hybrid vehicle are presented. In one example, driveline operating modes may be adjusted in response to driving surface conditions. The approaches may improve vehicle drivability and reduce driveline degradation.

Abstract: A motor drive system configuration for a vehicle. The motor drive system includes an engine operable for providing power to the vehicle, a motor operable for providing power to a first wheel and a second wheel of the vehicle. The motor drive system also includes a first transmission mounted between the engine and the motor and in operative engagement with the motor and the engine. The first transmission includes a first clutch for coupling and decoupling the motor with the engine. The motor drive system also includes a differential in operative engagement with the transmission and coupled to the first wheel and the second wheel, and a clutch for disabling the connection between the motor and the wheels.

Abstract: The embodiments herein provide an automatic clutch system for automobiles. The system comprises a mechanical section and an electronic section. The mechanical section comprises a rail support base with a rail-shaped ridge installed, dynamic parts installed on the rail-shaped ridge, supporting arms, an elevator mechanism connected to the clutch pedal and a clutch pedal lever. The electronic section comprises an input section for placing the elevator mechanism in due place and a keyboard for regulation, a sensor circuit, a command circuit including microcontroller, an exit section for changing a position of the elevator mechanism, a feedback circuit including a rotary encoder and monitors. The command circuit processes an instruction data from the input resources based on the regulations set by the user and transmits a command to the output section to position the elevator mechanism.

Abstract: A vehicle drive including an input coupled to an engine, an output coupled to wheels, an intermediate member between the input and output and coupled to a rotary electric machine, a friction engagement device between the input and intermediate member, and a control device. The control device, when starting the engine with the friction engagement device disengaged, engages the friction engagement device when a rotational speed difference between the input and intermediate member is equal to or less than a predetermined value; raises a rotational speed of the input using the rotary electric machine with the friction engagement device engaged to start the engine; and, when a rotational speed of the engine is equal to or more than a predetermined value, reduces an engagement pressure of the friction engagement device and the friction engagement device is returned to the engaged state when the rotational speed difference reaches a threshold.

Abstract: An automated start/stop system for a vehicle comprises an auto-stop module, a diagnostic module, and an auto-start module. The auto-stop module selectively initiates an auto-stop event and shuts down an engine while the vehicle is running. The diagnostic module selectively diagnoses a fault in a clutch pedal position sensor of the vehicle. The auto-start module, while the vehicle is running and the engine is shut down, selectively initiates an auto-start event after the fault has been diagnosed when current drawn by a starter motor is less than a predetermined maximum starting current.

Abstract: A hybrid vehicle is taught herein in which a clutch is disposed between an engine and a motor/generator and disengagement of the clutch is controlled in a coasting drive while dragging the engine. A drive controller engages the clutch so that the vehicle coasts while dragging the engine at a time of coasting deceleration. While coasting, when the stepped transmission of the hybrid vehicle downshifts, the clutch is disengaged during the downshift.

Abstract: The second clutch is caused to transition to an engaged state after setting the second clutch in a slip state when the vehicle starts in the hybrid start mode, the temperature of a magnet of the electric motor is estimated based on the temperature of the hydraulic oil and an operating condition of the electric motor when the second clutch is controlled to be in the slip state; and an output torque and a lower limit rotation speed of the electric motor is restricted and reduced when the estimated temperature of the magnet exceeds a restrictive temperature.

Abstract: In a hybrid vehicle having a locking mechanism in which a play elimination process is required in the locking, a torque shock in the play elimination is reduced. In a hybrid vehicle 1 having a locking mechanism 700 which is a cam-lock type engaging apparatus, an ECU 100 performs MG1 locking control. In the control, play is formed between a cam 710 and a clutch plate 720 of the locking mechanism 700. The formed play is gradually reduced such that the torque shock in the play elimination does not occur due to the phase control of the cam 710, on the basis of an initial value of the amount of the play when the clutch plate 720 is bought into contact with a friction part 733 and a play elimination amount G.

Abstract: A drive apparatus in a self-propelled construction machine comprises a milling rotor and a main drive which can be coupled to the milling rotor via an engaging and disengaging clutch, and an auxiliary drive which can be coupled to the milling rotor alternatively to the main drive. The clutch is provided with a fixed side and an axially displaceable output side, which is displaceable between an engaged position and a disengaged position. The axially displaceable side is simultaneously also the engaging and disengaging part of a shiftable transmission, the fixed part of which is driven by the auxiliary drive, with the transmission and the clutch being engaged and disengaged in a selective fashion via the axially displaceable side of the clutch.

Abstract: A multi-ratio rotorcraft drive system and a method of changing gear ratios thereof are disclosed. According to one embodiment, the multi-ratio rotorcraft drive system comprises a rotor system comprising one or more rotors and one or more engines. Each engine of the one or more engines is coupled to the rotor system through a multi-ratio transmission. The multi-ratio transmission comprises an output shaft coupled to the rotor system, an input shaft coupled to a respective engine of the one or more engines, a high speed clutch integrated into a high speed gear train, and a low speed clutch integrated into a low speed gear train. The high speed clutch and the low speed clutch are freewheeling clutches without a friction plate and are capable of disconnecting the output shaft and the input shaft in an overrunning condition when the output shaft spins faster than the input shaft.

Abstract: A vehicle control device that includes an input member drive-coupled to an engine and a rotary electrical machine; an output member; and a transmission having a plurality of friction engagement elements, in which a plurality of shift speeds are switched by controlling engagement and release of the plurality of friction engagement elements, and a rotary driving force of the input member is shifted by a change gear ratio of one of the shift speeds and outputted to the output member.

Abstract: A power transmission controlling apparatus of a vehicle includes a clutch capable of connecting/disconnecting power transmission between an engine and a motor/generator, and a torque converter enabling power transmission between the engine or/and the motor/generator and an automatic transmission. When the engine is started by motoring torque with engagement of the clutch during rotation of the motor/generator, the power transmission controlling apparatus sets a torque compensation amount by the motor/generator based on an estimated torque capacity of the clutch, and suppresses torque fluctuations on a power transmission path accompanying engagement of the clutch by power of the motor/generator containing the torque compensation amount. The power transmission controlling apparatus corrects the torque capacity or the torque compensation amount based on input torque of the torque converter.

Abstract: A hybrid electric vehicle powertrain having a mechanical power source and an electro-mechanical power source, including a generator, a motor and a battery. Driving torque developed by the mechanical power source is delivered through one clutch of a geared transmission to a power output shaft. The electric motor of the electro-mechanical power source delivers driving torque through a second clutch of the geared transmission. A mechanical reverse drive torque is used to improve reverse drive performance. A reduction in duration of operation in a negative power split during a driving event is achieved to improve vehicle powertrain efficiency. A series drive is available as the mechanical power source drives the generator to charge the battery, which drives the motor. The generator may act as an engine starter motor.

Abstract: A vehicle driving system 1 includes a first and second engines ENG1 and ENG2, a first and second transmissions TM1 and TM2 with first and second one-way clutches OWC1 and OWC2 provided in each output portion respectively, a driving target member 11 connected to output members 121 of the one-way clutches OWC1 and OWC2 in common via clutch mechanisms CL1 and CL2, a main motor/generator MG1 connected to the driving target member 11, and a controller 5. The controller 5 disconnects the clutch mechanisms CL1 and CL2 when a vehicle runs rearward, the transmissions TM1 and TM2, and runs the vehicle rearward by a reverse rotation operation of the motor/generator MG1. The controller otherwise holds the clutch mechanisms CL1 and CL2 connected at the time of a start on an uphill and obtains a hill hold function using a rearward running blocking operation through the transmissions TM1 and TM2.

Abstract: 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.

Abstract: A motor transmission apparatus is provided between a transmission output shaft coupled to a drive wheel and a motor shaft coupled to a motor/generator. The motor transmission apparatus includes a first power transmission path that is switched to a power transmission condition by a high clutch having a clutch oil chamber, and a second power transmission path that is switched to a power transmission condition by a low brake having a brake oil chamber. Working oil discharged from an oil pump is guided to an oil passage switching valve via an output control valve. The working oil is distributed to one of the clutch oil chamber and the brake oil chamber by the oil passage switching valve, and therefore interlocking, in which the high clutch and the low brake are engaged simultaneously, can be avoided.

Abstract: A vehicle control system with a hybrid drive comprising an engine and an electric motor and a plurality of functional components each divided into a strategy sub-component, a control sub-component and an actuator sub-component. The functional components include at least engine, transmission and hybrid functional components. The strategy sub-component (8) of the hybrid functional component (4) comprises an operating status prescription module (17) which reads in a first quantity of data from functional components in order to determine a prescribed value for the operating status of the hybrid drive, processes the read in data in order to produce a second quantity of output variables, and in a second sub-module (29), determines the prescribed value for the operating status of the hybrid drive using the output variables from the first sub-module (27) and with the help of automatic status-determining mechanism.

Abstract: Method for controlling the functioning of two heat engines connected to a torque distributor (5) in a fire-fighting vehicle, each engine being provided with automatic transmission and with a first clutch (K1) connecting the first (A) of said engines to a delivery pump of a liquid; with a second clutch (K2) connecting the first engine (A) to the vehicle's traction; with a third clutch (K3) connecting the second engine (B) to the vehicle's traction. The control has an activation or a deactivation step of said delivery pump, by closing or opening said first clutch (K1) at a vehicle speed lower than a threshold higher than zero, and in a condition of decelerating vehicle, with the simultaneous opening or closing of said second clutch (K2), and if said conditions are verified within an interval of time from an activation or deactivation request.

Abstract: A vehicle includes a powertrain with an engine, first and second torque machines, and a hybrid transmission. A method for operating the vehicle includes operating the engine in an unfueled state, releasing an off-going clutch which when engaged effects operation of the hybrid transmission in a first continuously variable mode, and applying a friction braking torque to a wheel of the vehicle to compensate for an increase in an output torque of the hybrid transmission resulting from releasing the off-going clutch. Subsequent to releasing the off-going clutch, an oncoming clutch which when engaged effects operation of the hybrid transmission in a second continuously variable mode is synchronized. Subsequent to synchronization of the oncoming clutch, the oncoming clutch is engaged.

Abstract: A vehicle drive device that includes a speed change mechanism; a fluid transmission device provided closer to an engine attachment side than the speed change mechanism is and including a lock-up clutch; an electric motor having a rotor and a stator and connecting the rotor to an input portion of the fluid transmission device; and an engine power cut-off clutch that transmits or cuts off a driving force of an engine to or from the fluid transmission device.

Abstract: A power transmission device has a rigid body that includes a contact portion coming into contact with the first or second friction member and that moves the contact portion from a position of contact with the first or second friction member to a position of no contact with the first and second friction members, an elastic body that applies to the rigid body a force moving the contact portion to a position of contact with the first or second friction member, a first pushing mechanism that applies to the rigid body a pressure of liquid moving the contact portion to a position of contact with the first or second friction member, and a second pushing mechanism that applies to the rigid body a pressure of liquid moving the contact portion to a position of no contact with the first and second friction members.

Abstract: A method for operating a hybrid vehicle, having at least one first drive unit and one second drive unit, the second drive unit being started by at least one portion of the drive torque provided by the first drive unit in that the clutch situated between the first drive unit and the second drive unit is brought from a disengaged state into a slipping state. To improve the driving comfort of the hybrid vehicle during a start or a stop of the internal combustion engine, at least two clutches are shifted into the slipping state for starting the second drive unit.

Abstract: In an energy storage and recovery system for a hybrid vehicle 1, the operating ratio range of a continuously variable transmission (CVT) 10 which transfers drive between the vehicle's driveline 8 and a flywheel 9 is effectively extended by the use of an integrated starter-generator (ISG) 13 connected to the flywheel shaft 12. When there is a high mismatch of rotational speed between the propshaft 8 and the flywheel shaft 12, prior to connecting the two shafts by a clutch 11, the ISG 13 either spins up or decelerates the flywheel 9 until its speed is brought within the optimum operating range of the CVT 10. This measure reduces wear and tear on the clutch 11.

Abstract: A hybrid engine and coupling system for use with a vehicle or other load which employs a motor/generator unit connected through controllable couplers to a kinetic energy storage device and to one or more internal combustion engine modules in a programmed manner. Several embodiments provide varying configurations to satisfy various power and packaging design requirements.

Abstract: A method to execute a shift in a powertrain including a plurality of torque generative devices rotatably connected through a first clutch includes operating the powertrain in a continuously variable operating range state, and monitoring a command to execute the shift including monitoring a target speed for a first torque generative device, and monitoring a command to disengage the first clutch. The first clutch is shifted from an engaged state to a disengaged state, including operating a torque phase of the first clutch wherein the first clutch is transitioned from the engaged state to the disengaged state, and simultaneous with the torque phase, operating an inertia speed phase of the first clutch wherein a speed of the first torque generative device is transitioned from an initial speed to the target speed.

Abstract: A method for activating an oncoming clutch in a transmission includes monitoring rotational speeds of clutch elements of the oncoming clutch wherein the clutch elements are coupled to first and second rotationally independent torque actuators. A control speed profile for the first rotationally independent torque actuator is commanded. A speed profile of the oncoming clutch approaching zero speed is generated as is a control speed profile for the second rotationally independent torque actuator corresponding to a speed of the first rotationally independent torque actuator, the speed profile of the oncoming clutch, and an output speed of the transmission. A speed of the second rotationally independent torque actuator is controlled using the control speed profile for the second rotationally independent torque actuator. A speed of the oncoming clutch is monitored and the oncoming clutch is activated when the speed of the oncoming clutch is zero.

Abstract: A system and method of dithering speed and/or torque for shifting a transmission of a vehicle having an engine, a reversible, variable displacement hydraulic motor/pump which can be driven by the engine, a hydraulic accumulator supplied by said motor/pump, and at least one reversible hydraulic driving motor for propelling the vehicle supplied with fluid by the hydraulic accumulator and/or by said motor/pump operating as a pump. A transmission unit connects the engine with the variable displacement hydraulic motor/pump during a first mode of operation (city mode) and connects the engine to a vehicle drive wheel during a second mode of operation. The system utilizes stored hydraulic energy to dither the output of the driving motor in order to achieve quick and smooth shifts between city and highway mode, or between various ranges within the city mode.

Abstract: A method for operating a motor vehicle hybrid powertrain having an engine, a motor-generator and a multi-speed automatically-shiftable transmission, wherein the engine and the motor-generator operate to supply torque to the transmission for driving a vehicle. The method includes modulating the torque supply from the motor-generator to the transmission during a gear shift to minimize a transmission output torque disturbance.

Abstract: A method of operating a hybrid drive system with an internal combustion engine and a supplemental electric machine for a motor vehicle including first and second gear changing partial drives each with gear changing gearwheels, wherein during operation there is torque flow from one gear changing partial drive to the other partial drive results in a gear change between gearwheels.

Abstract: The invention relates to a method of transmitting power between a shaft of a heat engine and a wheel axle shaft of a hybrid vehicle. The inventive method involves the use of: a power transmission device comprising an electric machine which is connected to (i) the heat engine by means of a clutch and (ii) a wheel axle shaft; and a starting system which is mechanically independent of the electric machine and which is connected to the heat engine. According to the invention, the heat engine is started by applying a torque to the shaft simultaneously using the starting system and the clutch.

Abstract: A power unit has: a conversion device (3, 106) for converting mechanical energy of rotation into a different form of energy which can be used for various purposes; a first internal combustion engine (1, 102); a second internal combustion engine (5, 104); a first clutch (2, 103) through which the first engine can be selectively coupled to a first axial end of a rotor shaft of the conversion device for transmitting mechanical energy of rotation to the rotor shaft when the first clutch is engaged; and a second clutch (4, 105) through which the second engine can be selectively coupled to a second axial end of the rotor shaft for transmitting mechanical energy of rotation from the second engine to the rotor shaft when the second clutch is coupling the second engine to the rotor shaft.

Abstract: An apparatus for improving fuel efficiency of a vehicle is provided, including an engine, a generator system and an air-conditioning system. The generator system and the air-conditioning system are connected respectively through transmission elements and a moveable first active transmission wheel and a second active transmission wheel on the engine core axis. A first clutch is placed between the crank shaft of the engine and the first active transmission wheel, and a second clutch is placed between the first active transmission wheel and the second active transmission wheel. Also, a control circuit is provided to control the operation of the first clutch and the second clutch, in order to control the driving and rotation of the first active transmission wheel and/or the second active transmission wheel. The control circuit further determines according to the signal whether power is provided directly to the generator system and further drives the air-conditioning system.

Abstract: According to this method for controlling the coupling and the decoupling of the first and second motors of a parallel hybrid motive power group comprising a first motor driving an input shaft, a second motor, and a coupling/decoupling means motors, maneuverable between an open position and a closed position, the motive power group is controlled so that the rotational speed of the input shaft at the moment of coupling and of decoupling remains unchanged while using a law of control that creates a discontinuity between the torques output to the input shaft when the first and the second motors are decoupled or coupled, selected for compensating for the difference between the inertias produced by the input shaft when the first and the second motors are decoupled or coupled in order to ensure a continuity of the acceleration of the input shaft when coupling or decoupling.

Abstract: A method for actuating a starting clutch in the power train of a hybrid vehicle, where during a starting phase of the combustion engine by means of an electric machine the starting clutch operating between them is engaged in a first starting phase by means of a pre-control and in a second starting phase depending on the acceleration of the crankshaft of the combustion engine.

Abstract: To detect opening/closing of a neutral detection hydraulic switch by a detection apparatus and detect breakage of a wiring line connected between the detection apparatus and the switch. Since a second contact and an ECU are connected to each other by two wiring lines, even if one of the wiring lines is broken, opening/closing of the neutral detection hydraulic switch can be detected through the remaining one of the wiring lines. Since different voltages are applied to the wiring lines through resistance type voltage dividing circuits, the occurrence of the wire breakage can be detected making use of the fact that the voltage detected by the ECU upon opening of the neutral detection hydraulic switch when one of the wiring lines is broken is different from the voltage when none of the wiring lines is broken.

Abstract: A control device for hybrid vehicle drive apparatus has a differential mechanism operative to perform a differential action and an electric motor. The control device prevents a second electric motor from reaching a high-speed rotation with a likelihood of degradation occurring in durability of the second electric motor when a “D” position is switched into an “N” position during a running of a vehicle. When a shift lever (49) is shifted into the “N” position during the vehicle running to interrupt a power transmitting path of an automatic shifting portion (20), a differential action of a power distributing mechanism (16) is limited. A limited differential action suppresses increases in rotation speeds of rotary members such as a clutch or a brake of the automatic shifting portion (20), a second electric motor (M2) and a differential-portion planetary gear (P0) or the like. Thus, degradation in durability of such rotary members due to high-speed rotations thereof can be minimized.

Abstract: A method for adjusting the friction coefficient of a friction clutch situated in a hybrid power train between an electric machine and a combustion engine, actuated by a clutch actuator, the friction coefficient is adjusted by a torque transmitted by the friction clutch, which is determined when starting the combustion engine by the electric machine.

Abstract: A torque transmission assembly is disposed between a power source and a vehicle transmission and includes an annular housing, a pump member of a fluid coupling, a turbine member of the fluid coupling, a lockup clutch, a first shaft, a first selectable clutch, a second shaft, and a second selectable clutch. The turbine member opposes the pump member and the lockup clutch is selectively engaged between the pump member and the turbine member. The first selectable clutch is selectively engaged between the turbine member and the first shaft. The second selectable clutch is selectively engaged between the turbine member and the second shaft.

Abstract: A method for controlling a hybrid electric vehicle powertrain includes operating an engine driveably connected to first vehicle wheels, providing an electric motor driveably connected to second vehicle wheels, shifting a gear selector between a forward drive position and a reverse drive position, reducing vehicle speed to or lower than a reference speed, and using a transmission located between the engine and the first wheels and the electric motor to produce reverse or forward drive corresponding to the position to which the gear selector is shifted.

Abstract: A vehicle control system reduces vehicle rollback upon brake release. The control system includes a brake system, a vehicle grade measurement device and a controller that modulates applied brake pressure of the brake system based on a grade measurement of the grade measurement device. The controller actuates brake-hold device communicating with the brake system based on the grade measurement through pulse width modulation. The control system communicates with a motor generator and an engine to provide a start power to the engine upon brake release based on the grade measurement. Fuel injectors of the engine are enabled upon brake release based on the grade measurement. The control system further communicates with a transmission forward clutch to provide selective rotational communication between the transmission and the engine based on the grade measurement.

Abstract: Controlling a hybrid powertrain includes monitoring an operator torque request, determining maximum and minimum allowable transmission output torques based upon the operator torque request, determining a commanded transmission output torque, and comparing the commanded transmission output torque and each of the maximum and minimum allowable transmission output torques.

Abstract: A method for controlling a hybrid drivetrain of a motor vehicle such that, during a thrust operation of the vehicle, a change takes place from a combustion-powered driving mode, in which the combustion engine is in a thrust operation, the separator clutch is engaged and the electric machine contributes no force, or from a combined driving mode in which the engine is in a thrust operation, the clutch is engaged and the electric machine operates as a generator, to an electric driving mode in which the engine is switched off, the clutch is disengaged and the electric machine operates as a generator. To efficiently change driving modes, the clutch is partially disengaged to a slip limit; the clutch is then completely disengaged; and when the clutch reaches the slip limit, the generator torque of the electric machine is increased inversely to the torque that can be transmitted by the clutch.

Abstract: In a method for starting a hybrid vehicle having a first drive unit and a second drive unit, the setpoint starting torque is generated by the second drive unit. In this method, a starting clutch for connecting the first drive unit is brought into the slipping state when a predefined setpoint torque of the second drive unit is exceeded.

Abstract: A control apparatus for a drive system of a vehicle includes (a) an electrically controlled differential portion having a differential state between rotating speeds of an input and an output shaft being controlled by controlling an operating state of a first electric motor, (b) a switching portion operable to switch a power transmitting path between the output shaft and a drive wheel of the vehicle, between a power transmitting state and a power cut-off state, and (c) a second electric motor connected to the power transmitting path. The control apparatus includes an excessive speed preventing portion configured to limit a rotating speed of the output shaft or an operating speed of the second electric motor when the power transmitting path is switched by the switching portion from the power transmitting state to the power cut-off state.

Abstract: A method for controlling a motor vehicle drive train including a combustion engine, an electric machine and a transmission, which are coupled by a summation gear system, having two input and one output elements, and a clutch. One input element is coupled to the crankshaft of the combustion engine, the other input element is coupled to the rotor of the electric machine and the output element is coupled to the input shaft of the transmission and the clutch is arranged between two elements of the summation gear system, such that when the clutch is disengaged a speed difference between the combustion engine and the transmission input shaft is synchronized by the electric machine and, if necessary, by a controlled engagement of the clutch. To improve synchronization, at the beginning of the synchronization the clutch is brought to its contact point before the engagement of the bridging clutch.

Abstract: A control device for a vehicle which includes a differential portion controlling a differential state between the number of rotations of an input shaft connected to an engine, and the number of rotations of an output shaft connected to drive wheels, with controlling an operating state of an electric motor, and an automatic shifting portion forming part of a power transmitting path. The control device prevents degradation in operability of the vehicle, even in the presence of a shifting command resulting from a manual shift operation when the automatic shifting portion remains under a limited shifting state. More particularly, if the shifting command is present due to the manual shift operation, the differential state of the differential portion is controlled, thereby causing a variation in a drive force at a rate corresponding to the shifting command.

Abstract: An automotive transmission transitions from a drive gear to a neutral gear when an engine is shutdown. During a rolling pull-up, a crankshaft of the engine will be spun up to a desired speed and the transmission will transition from the neutral gear to an appropriate gear based on a shift schedule. A target transmission input speed is commanded to be a synchronous speed plus an offset to smoothly transition out of electric axle drive propulsion.

Abstract: A powertrain is provided with a first input clutch and a second input clutch, each of which is selectively engageable to connect an engine with a transmission input member. Selective engagement of the first input clutch permits a motor to power the engine to start the engine. Selective engagement of the second input clutch permits the engine to power the transmission for propulsion.

Abstract: When the power transmitting path in an automatic shifting portion (20) is interrupted, a Co-lock control is executed to allow a differential portion (11) to be placed in a non-differential or nearly non-differential state with rotary elements (RE1 to RE3) kept in a unitary rotation. Thus, an engine (8), a first electric motor (M1) and a second electric motor (M2) rotate at an identical or nearly identical speed. Then, for the purpose of controlling the second electric motor (M2) at a rotation speed below a permit rotation speed, it may suffice for the first and second electric motors (M1) and (M2) to be driven in a direction to lower relevant rotation speeds while monitoring any one of an engine rotation speed, a first-motor rotation speed and a second-motor rotation speed. This allows such a control to be easily executed, thereby preventing the second electric motor from reaching a high speed rotation.

Abstract: A control system for a drive unit of a vehicle, in which a power distribution mechanism is arranged on a route from a prime mover to a wheel, and a transmission is arranged on an output side of the power distribution mechanism. The control system includes a revolution frequency controller that restrains a variation in a revolution frequency of the prime mover by controlling a revolution frequency of the reaction force establishing device until a predetermined time elapses since a commencement of a shifting operation of the transmission. The control system is capable of restraining a variation in an output torque, in case of carrying out a shifting operation of a transmission arranged on an output side of a prime mover.