Abstract: This invention provides a vehicle control apparatus constructed so that during the control of a downshift for deceleration, braking shocks can be reduced and the amount of energy regenerated can be increased, and a hybrid vehicle equipped with the control apparatus. The hybrid vehicle 1 includes wheels 14, an engine 12, a motor 11, a multi-stage transmission 20 that reduces motor torque and transmits the reduced torque to the wheels, and a brake 15 that brakes the wheels. During deceleration downshift control, a hybrid control module 100 provides distribution control of the regenerative torque of the motor 11 and the braking torque of the brake 15 so that the total braking force of the vehicle during gear shifting matches a target value.

Abstract: A vehicle has an internal combustion engine (ICE) and a electric traction motor (ETM) coupled by a standard transmission through a differential to drive traction wheels. A control system receives sensor signals including speed sensors, a load sensor, and an incline sensors. The control system processes the speed signals to generate indicator signals corresponding to speed of the ETM, the vehicle speed, the shifting gears and the speed of the transmission output shaft. One or more displays present indications of when the speed of a shifting gear corresponding to the speed of the ETM matches the speed of the vehicle thus the speed of the transmission output shaft. An operator may shift, without clutching, from neutral and to a next shifting gear when there is an indication that the speed of the next shifting gear matches the speed of a shifting collar coupled to the transmission output shaft.

Abstract: Electrical power from a dynamic braking process in an off-highway vehicle is used to power an auxiliary system in the vehicle. The auxiliary system may be a urea storage container heating unit or a particulate filter regeneration heating unit. When dynamic braking electricity is unavailable, and to the extent the dynamic braking electricity is insufficient for powering the auxiliary system, electrical power from an energy device on board the vehicle is used to power the auxiliary system. The energy device may be an auxiliary energy storage device, devoted for use in powering the auxiliary system.

Abstract: A shock caused due to a change in the direction of torque transferred to an output shaft is reduced. There is provided a control device for a powertrain including a drive power source that transfers torque to an output shaft connected to a wheel of a vehicle, and a rotary electric machine that transfers torque to the output shaft via a transmission. When electric power generation performed using the rotary electric machine is restricted, if torque that decelerates the vehicle is transferred from the drive power source to the output shaft, a control is executed so that torque that does not decelerate the vehicle is transferred from the drive power source to the output shaft, and a shift control over the transmission is executed.

Abstract: A hybrid vehicle control system for cutting off fuel to an internal combustion engine of hybrid vehicle while providing smooth transitions from a hybrid drive mode to an electric drive mode is provided. The hybrid vehicle control system includes an integrated controller configured to receive inputs corresponding to vehicle speed and an indicated driving force, and to select an appropriate mode transition pattern from a group of mode transition patters according to the change in indicated driving force.

Abstract: A deceleration control apparatus for a hybrid electric vehicle in which an electric motor conducts regenerative braking when the vehicle is to be decelerated comprises a braking unit for applying a braking force on a drive member transmitting drive power converted by a parallel axes-type automatic transmission to wheels, and a control unit for controlling the braking unit to apply a braking force on the drive member while a downshift is being conducted in the automatic transmission in the process of deceleration of the vehicle.

Abstract: A method of operating a hybrid powertrain is provided that permits operation in multiple fixed ratio modes appropriate for towing and other vehicle operating conditions in which relatively high output torque is required. The method includes establishing three different electrically-variable operating modes by engaging different torque-transmitting mechanisms in response to different respective vehicle operating conditions. The method further includes establishing at least two different fixed ratio modes by engaging another torque-transmitting mechanism in addition to the respective different torque-transmitting mechanisms engaged to establish the electrically-variable operating modes. A hybrid powertrain having a controller configured to control the powertrain to operate according to the method is also provided.

Abstract: The embodiments described herein include a control system and method for a vehicle. In one embodiment, the control system is able to determine the occurrence of NVH anomalies due to gear lash and control the operation of various vehicle devices to reduce the effects of gear lash. If such NVH anomalies are foreseen, a predetermined torque is applied to the vehicle wheels for a predetermined time period. Subsequently, the applied torque is gradually increased until a creep torque is reached.

Abstract: Method for recovering electrical energy in a vehicle with regenerative braking is used in a vehicle equipped for this purpose with an electrical capacitance device to store electrical energy supplied by a rotary electrical machine of the vehicle during regenerative braking operation. A choice is made, on the basis of the initial rotational speed of the rotary electrical machine to apply an energy recovery stratagem from at least the following two: —a first energy recovery strategy that favors high power supplied by the rotary electrical machine; and—a second energy recovery strategy that favors high efficiency of the rotary electrical machine.

Abstract: A control device is provided for a power train including: a differential mechanism having a first rotating element linked to a first rotary electric machine, a second rotating element linked to a second rotary electric machine and a third rotating element linked to an internal combustion engine; a switching mechanism that switches between a first state that permits relative rotation of the first, second and third rotating elements, and a second state that prohibits relative rotation thereof; and a transmission mechanism connected to the differential mechanism which transmits torque from the differential mechanism to a wheel. The control device includes: a first control portion that controls the switching mechanism so as to switch between the first and second states; and a second control portion that compensates for an amount of change in the torque transmitted to the wheel when the switching between the two states is performed.

Abstract: A method of operating a drivetrain of a motor vehicle. The drivetrain comprising a drive aggregate with at least one electric machine. During operation of the drivetrain according to the method, when an accelerator pedal and a brake pedal are not actuated, the drivetrain is operated in a speed-regulated crawling mode and during this mode a nominal speed value is compared with an actual speed value and, on the basis of the difference between these speed values, a crawling torque is produced as a control output. During a purely electrical speed-regulated crawling operation, if a positive crawling torque is produced as the control output, then the torque produced by the electric machine is regulated such that the actual speed value is approximately equal to the nominal speed value and, during such operation, an electrical energy accumulator of the drivetrain is discharged more intensively since the electric machine is operated as a motor.

Abstract: A powertrain control system for management and supervision of engine and servo-assisted gearbox control modules is arranged for determining the power to be applied to the drive wheels of the vehicle as a function of signals indicative of commands imparted by the driver, of the engine and gearbox state parameters and of possible requirements from the engine and gearbox control modules and supplementary on board vehicle traction/drive control systems; calculating data indicative of the torque to be delivered at the engine drive shaft, the torque transmissible by the clutch and the required transmission ratio, as a function of the determined value of the power to be applied to the drive wheels, of the state parameters and of the requirements of the engine and gearbox control modules and the traction/drive control systems; and transmitting the calculated data as signals to the engine and gearbox control modules.

Abstract: A hydraulic energy storage system (comprising a hydraulic pump/motor, a high pressure hydraulic accumulator, a low pressure hydraulic accumulator/reservoir, and interconnecting hydraulic lines) is incorporated into a EV, HEV, or PHEV to provide hydraulic regenerative braking and propulsive assistance for the vehicle. Implementation of the low cost and long-lasting hydraulic energy storage system in the vehicle, together with the electric energy storage system (comprising a motor/generator and battery pack) of the vehicle, allows significantly reduced demands and higher operating efficiencies for the battery pack, thereby facilitating a more cost-effective, efficient and/or durable overall energy storage system for the vehicle.

Abstract: An engaging device (a switching clutch C0 or a switching brake B0) switches a shifting mechanism 10 between a continuously variable shifting state and a step-variable shifting state. In particular. The step-variable shifting state is set in a high speed running, because a first electric motor M1 need not bear a reaction torque against an input torque TINS inputted into a differential portion 11, the first electric motor M1 is prevented from being large-sized and suppressed in durability lowering. Even when switching to the step-variable shifting state is unable, the input torque TINS against which the first electric motor M1 should bear the reaction torque, is limited by an input torque control means 86, and the first electric motor M1 is prevented from being large-sized and suppressed in durability lowering.

Abstract: A process and device for controlling the brake system of a motor vehicle with all-wheel drive are described. The process and the device include an electronic control unit which controls at least one coupling unit for engaging and disengaging an all-wheel drive, so that at least one wheel can be decoupled, from the drive. After stopping the motor vehicle, for example on a sloping roadway, a predefined brake pressure on at least one wheel of the motor vehicle is held either depending on or independently from the extent of brake pedal actuation. The brake pressure is held until a brake pressure reduction condition is present, such as during a brake pressure holding time. During that time, the brake pressure on at least the one wheel is reduced and the wheel is decoupled from the drive to detect slippage, while at least one other wheel remains pressurized with brake pressure.

Abstract: The invention relates to a method for braking a hybrid vehicle (1) including a thermal engine and an electric machine (3) defining a traction chain. According to this method, when the depression of the brake pedal is detected, an additional electric braking torque is added (Cf_recup), and the additional electric braking torque is modulated according to the position of the brake pedal as measured by a pedal stroke sensor (42) and/or to the braking hydraulic pressure as measured by a braking pressure sensor (43).

Abstract: A vehicle control system is comprised of a controller which is arranged to select an optimal mode adapted to a driving point of a vehicle from an optimal mode map of defining a plurality of running modes of the vehicle, to detect a generation of a mode transition in the optimal mode map, and to hold a current running mode selected before the transition for a holding time period when the generation of the mode transition is detected.

Abstract: A method of operating a drive train of a motor vehicle with a hybrid drive having an internal combustion engine, an electric motor, an automatic transmission. The drive train also having a clutch between the internal combustion engine and the electric motor, and a clutch or a torque converter between the electric motor and the automatic transmission. This arrangement enabling the internal combustion engine to be started by engaging the clutch arranged between the internal combustion engine and the electric motor, when the drive train is powered exclusively by the electric motor. The braking power, generated during an upshift in response to a drop in the rotational speed of the drive train components, is used to start the internal combustion engine, such that the energy required from the electric motor for starting the combustion engine is minimized.

Abstract: A braking method and device with energy recovery for a hybrid traction vehicle, which, according to the requested braking target, regulates the intervention of the engine-generator and the connection or disconnection of the endothermic engine from the transmission line.

Abstract: An anti roll back (ARB) control system and an ARB control method are provided, which can prevent a hybrid vehicle, of which the clutch disposed between the driving wheel and the engine is open when the vehicle stops, from being unexpectedly moving downward when the vehicle is restarted on a slope.

Abstract: A vehicle powertrain for a hybrid vehicle includes an electronically variable transmission (EVT) with an input member to receive mechanical rotary power from the engine, an output member to provide mechanical rotary power to a vehicle powertrain to propel the vehicle, and an EVT gear train configured to selectively and operatively couple the input member to the output member. The EVT further includes first and second motor/generators driveably coupled to the gear train. A selectively engageable input brake mechanism is provided to create a reaction torque for the motor/generators thereby enabling the motor/generators to be used with additive power for electric propulsion or regenerative braking. The input brake improves electrical power to mechanical power conversion efficiency by reducing power circulation when the EVT is operated in electric drive, engine off mode.

Abstract: A method of controlling an automated step-down transmission, arranged in a drivetrain between an engine and a drive axle, which includes a multi-stage main transmission and a range group. The main transmission has an intermediate transmission style with a countershaft having a transmission brake and an input shaft connected, via a clutch, to the engine. The main transmission shifts, without being synchronized, and the range group shifts, after synchronization, such that the engaged gear ratio of the main transmission remains engaged during a range shift operation. The range shift is accomplished by firstly reducing drive engine torque; secondly, disengaging the existing gear ratio of the range group; thirdly, remotely synchronizing the target gear ratio in the range group; fourthly, engaging the target gear ratio in the range group; and fifthly, increasing the drive engine torque.

Abstract: In a motor vehicle having an internal combustion engine which has an automatic start/stop device, and a controllable brake device at the start of and during an automatic stop phase, the effect of a braking torque which is greater than a threshold value is ensured. For this purpose, the brake device can increase the braking torque. The threshold value is previously calculated in such a way that the motor vehicle is reliably prevented from rolling away. As a result, the internal combustion engine can be stopped frequently, and at the same time unintentional rolling away of the motor vehicle during the stop phase can be avoided.

Abstract: When a vehicle condition is in a region where limitation of the differential action of a differential portion should be stopped, for example in a CVT control region or a motor-driven region, a cutoff device prohibits the limitation of the differential action. Therefore, if the differential action may be limited due to a failure when the vehicle condition is in the region where the limitation of the differential action should be stopped, the fail-safe function is performed to prohibit the limitation of the differential action. This avoids the situation where fuel efficiency is decreased, driveability is deteriorated, and a shock is caused by limiting the differential action.

Abstract: A method for controlling shifting between a plurality of operating modes in a hybrid vehicle includes the steps of obtaining a plurality of throttle position values, generating a comparison between a first throttle position value of the plurality of throttle position values and a second throttle position value of the plurality of throttle position values, and selectively allowing a shift between at least two of the plurality of operating modes, based at least in part on the comparison between the first and second throttle position values.

Abstract: A control apparatus for a vehicular drive system including a continuously-variable transmission portion operable as an electrically controlled continuously variable transmission having a differential mechanism operable to distribute an output of an engine to a first electric motor and a power transmitting member, and a second electric motor disposed in a power transmitting path between the power transmitting member and a drive wheel of a vehicle.

Abstract: A torque control selection portion selects one of a first torque control portion and a second torque control portion as a control portion that controls a torque output from an automatic transmission, based on a vehicle condition. The first torque control portion controls the output torque by controlling an engagement pressure for a first clutch or a second clutch. The second torque control portion controls the output torque by controlling a reaction torque borne by a first motor when transmission of power is permitted in a shift mechanism.

Abstract: A method for wear-free braking of a vehicle having an electrodynamic drive system including an electric machine and a planetary gearset with a crankshaft of the combustion engine being connected with a first element of the gearset, the electric machine connected to a second element of the gearset and a transmission input shaft connected to a carrier of the gearset. The friction clutch serves as a bridging clutch to detachably connect two elements of the gearset such that when the clutch is engaged, the gearset is locked and the combustion engine operating in thrust mode applies braking torque to the drive train, the clutch is disengaged and a transmission input speed exceeds a predetermined threshold value, the speed of the combustion engine is raised to a maximum speed by appropriate control of the electric machine.

Abstract: Upon shifting control of differential mechanism 10, speed ratio ?0 of continuously-variable transmission portion 11 and speed ratio ? of automatic transmission portion 20 are determined by vehicle-output control device 82 on the basis of target engine output PE* and vehicle speed V, so as to establish an operating point of engine 8 which provides the target engine output PE* and which follows an optimum-fuel-economy curve, and the shifting control of the continuously-variable transmission portion 11 and the shifting control of the automatic transmission portion 20 are effected substantially concurrently, so that engine speed NE continuously changes, and the differential mechanism 10 is shifted with a reduced shifting shock. Further, the speed ratio ?0 of the continuously-variable transmission portion 11, in other words, the engine speed NE is changed by using first electric motor M1 and/or second electric motor M2, permitting an improvement in shifting response of the differential mechanism 10.

Abstract: An engine and a second power generating device transmit power through a transmission to a driveline to a wheel. A control module determines a regenerative braking axle torque capacity and a regenerative braking torque. Power output from the second power generating device is controlled based upon a regenerative braking axle torque request. A brake control module determines a total braking torque request and generates the regenerative braking axle torque request based upon the total braking torque request, the regenerative braking axle torque capacity, and the regenerative braking torque. The brake control module controls a friction brake.

Abstract: A method and device for determining a driving torque correction factor for compensating the driving torques of a drive unit including a first drive device and a second drive device, both of which act with their driving torque on a common drive shaft. The method includes specifying and setting a desired driving torque for one of the two drive devices, adjusting a brake torque for the other of the two drive devices to a brake torque value, which is equivalent to the value of the actual driving torque (that occurs on the basis of the desired driving torque) of one of the two drive devices, and determining the correction value as a function of the specified desired driving torque of the one drive device and as a function of the brake torque value of the other drive device, the brake torque value being adjusted at the time of the compensation of the torques.

Abstract: A combined hybrid drive and brake system for use with a rotatably driven mechanism includes a hybrid drive system that is adapted to decelerate a rotatably driven mechanism, accumulate the energy resulting from such deceleration, and use the accumulated energy to subsequently accelerate the rotatably driven mechanism. A brake system is adapted to decelerate the rotatably driven mechanism. A control apparatus is responsive to a request for braking torque for decelerating the rotatably driven mechanism by either (1) the hybrid drive system operating alone, (2) the brake system operating alone, or (3) both the hybrid drive system and the brake system operating in combination.

Abstract: A hybird power train structure having a toroidal variator. The hybird power train structure is constructed such that drive force generated by an engine and drive force generated by a motor are appropriately combined and transmitted to a drive wheel, thus having a quiet variable speed change characteristic despite having a relatively simple structure.

Abstract: In a hybrid vehicle having at least one electric motor which is usable as a generator and charges a vehicle battery during a recuperation phase, there is provided an additional actuating element independent of a brake system which is used to transfer the electric motor into its recuperation state without activating the brake system. Alternatively, the additional actuating element may operate in conjunction with the brake system, such that the brake pedal may also be used to transfer the electric motor into its recuperation state.

Abstract: In one embodiment, a first motor is used upon stopping or starting of an engine during driving of a vehicle. When a stop control or a start control of the engine is executed, a target drive force required to be generated by a second motor is calculated based on a drive force required for driving. A positive drive force required for elimination in a specific rotation direction of backlash occurring in mutual meshing sections of gears of a power distribution mechanism is added to the target drive force. Meanwhile, a braking force required of a brake in order to cancel the added positive drive force so as not to be transmitted to drive wheels is calculated. Based on the results of calculation, coordinated control is executed in which the second motor and the brake are operated in a linked manner.

Abstract: A method of applying regenerative braking on a hybrid vehicle may include operating the hybrid vehicle in a cruise control mode to maintain a desired vehicle speed, determining whether an actual vehicle speed is greater than the desired vehicle speed, and braking the hybrid vehicle using a regenerative brake system. The braking may be applied during operation in the cruise control mode when the actual vehicle speed is determined to be greater than the desired vehicle speed to charge a battery system that powers an electric drive motor of the hybrid vehicle.

Abstract: In one embodiment, a hybrid propulsion system for a vehicle is provided. The system comprises at least one drive wheel; a first motor coupled to the drive wheel, said first motor configured to selectively generate electrical energy from kinetic energy received at the drive wheel; a second motor configured to selectively generate electrical energy from kinetic energy received at the drive wheel; a transmission including a first end coupled to the first motor and a second end coupled to the second motor; and a control system configured to vary a level of electrical energy generated by the first motor relative to the second motor in response to a thermal condition of at least one of said first and second motors to provide vehicle braking.

Abstract: In response to a downshift operation (step S160) in a moving motor vehicle under an accelerator released state, a torque demand correction value T?(T) is set to give the greater torque variation against the lower speed in a downshifting gear position and against the higher vehicle speed V, until elapse of a preset time period since the downshift operation (step S180). A torque demand Tr* to be output to a drive shaft of the motor vehicle is updated by adding the torque demand correction value T?(T) to a previous setting of the torque demand Tr* (step S190). A motor is controlled to decelerate the motor vehicle with the updated torque demand Tr*. The torque variation thus attained is equivalent to a temporary torque variation applied to the drive shaft with a variation in rotation speed of an engine in response to a downshift operation in a conventional motor vehicle equipped with a stepped automatic transmission for torque conversion of the output power of the engine.

Abstract: An electric machine including an engine, generator, and motor. The electric grid is positioned between an input passage and output passage of an exhaust system of the engine. While in retard mode, excess electric power is dumped to the electric grid. Continuous airflow from the engine through the exhaust system removes the energy, in the form of heat, away from the electric grid.

Abstract: In a drive train of a motor vehicle comprising an internal combustion engine, at least one electrical machine which can be operated at least as a motor or as a generator, and a stepped automated manual transmission and at least one control device for controlling the internal combustion engine, the at least one electrical machine (P1, P2) and the stepped automated manual transmission and a method of operating the drive train, a braking torque on the driven wheels is kept approximately constant before, during and after a gear-shifting operation to a gear with a higher transmission ratio so as to avoid any jerks during such down shifting procedure.

Abstract: An ECU executes a program including the steps of: providing control over an engine coupled to a carrier for driving a first MG coupled to a sun gear in a power split device, and providing control over a second MG for allowing a ring gear to stop; expecting that a shift operation will be performed when a brake operation is performed; and stopping providing the control over the engine for driving the first MG and stopping providing the control over the second MG for allowing the ring gear to stop.

Abstract: A method for controlling a hybrid drive of a vehicle is described, the hybrid drive including as propulsion motors an internal combustion engine and at least one electric motor/generator, and the output shafts of the propulsion motors being operatively linkable to a power train of the vehicle. The propulsion motors and an electrically activatable braking system of the vehicle are activated in a coordinated manner as a function of a negative torque request, taking this negative torque request into account.

Abstract: A vehicle includes a drive device applying a driving force to a wheel, a brake device applying a braking force to the vehicle, and a control device controlling the drive device and the brake device. When the traveling direction and the acting direction of the driving force are opposite, the control device causes the drive device to generate a driving force corresponding to a driving force demand in the event of the drive device not entering an operation disallowed region even if the driving force corresponding to the driving force command is generated at the drive device, and causes the brake device to operate according to the drive driving force demand in the event of the drive device entering the operation disallowed region if the driving force corresponding to said driving force demand is generated at said drive device.

Abstract: An improved structure of a transmission structure for an electrically operated bicycle, structured to include an electric mechanism and a pedal coaxially disposed on a pedal shaft of a bicycle. The present invention is characterized in that: a rotating shaft of the electric mechanism is a hollow tube that passes through two sides of the electric mechanism; the pedal shaft of the pedal mechanism penetrates and is disposed within the rotating shaft and is able to rotate therein; and the driving chain wheel is pivotal disposed on an outer side of the rotating shaft. One side of the driving chain wheel is coupled to the rotating shaft of the electric mechanism by means of a clutch, and the other side of the driving chain wheel is coupled to a pedal crank of the pedal mechanism by means of a unilateral bearing.

Abstract: A control device for a vehicular drive system including a differential mechanism operable to distribute an output of an engine to a first electric motor and a power transmitting member, and a second electric motor disposed in a power transmitting path between the power transmitting member and a drive wheel of a vehicle. The control device includes a differential-state switching device operable to place the differential mechanism selectively in one of a differential state and a non-differential state, and a switching control device operable to control the differential-state switching device, so as to place the differential mechanism in the differential state when the vehicle is in a motor-drive mode in which at least one of the first and second electric motors is used as a drive power source to drive the vehicle.

Abstract: The present invention concerns a drive arrangement for the drive of attached implements for a vehicle, particularly an agricultural or industrial utility vehicle, with a combination gearbox, an electrical machine and a power take-off shaft, where a gearbox interface of the combination gearbox can be driven by an internal combustion engine and where the electrical machine is connected with a second gearbox interface of the combination gearbox. In order to make available a variable power take-off shaft rotational speed that is independent of the rotational speed of the internal combustion engine, the drive arrangement according to the invention is characterized by the fact that the power take-off shaft is connected with a third gearbox interface of the combination gearbox. Furthermore the present invention concerns a vehicle with such a drive arrangement.

Abstract: A method of controlling a vehicle includes reducing a speed of the vehicle in response to a vehicle shutdown signal, monitoring at least one of a speed of the vehicle and a torque of an engine of the vehicle, determining whether the monitored at least one of the speed and torque is decreasing, if the monitored at least one of the speed and torque is not decreasing, enabling the engine of the vehicle to operate at a reduced power level, and stopping the vehicle when the monitored at least one of the speed and torque has reached a predetermined level. A control system for a vehicle includes a processor that reduces a speed of the vehicle in response to a vehicle shutdown signal. The processor monitors at least one of a speed of the vehicle and a torque of an engine of the vehicle and determines whether the monitored at least one of the speed and torque is decreasing.

Abstract: A motor torque control system for a vehicle equipped with a drive torque generating motor is comprised of a vehicle speed detector, an accelerator opening detector, a brake depression detector and a control unit. The control unit rapidly brings a motor torque to zero when a vehicle speed is lower than a predetermined speed, when an accelerator opening is substantially zero, and when a brake depression quantity is increasing, and generates the motor torque according to the brake depression quantity when the brake depression quantity is deceasing.

Abstract: A mode switch control system for a hybrid transmission for a powertrain, the powertrain including an engine, a first motor/generator, and a second motor/generator, which controls a mode switch from a high speed mode to a low speed mode. The high speed mode is established by engaging a high-mode clutch. The low speed mode is established by engaging a low-mode brake. In the mode switch, the mode switch control system reduces the torque capacity of the high-mode clutch to zero linearly in time by an open-loop control system, and varies the torque of the second motor/generator to a target torque by a feedback control system so as to adjust the gear ratio to a target gear ratio, while the mode switch control system holds substantially constant the input torque from the engine, and the torque of the first motor/generator, to hold substantially constant the output torque.

Abstract: A powertrain includes an engine with an engine output member and a transmission with two motor/generators and a transmission input member operatively connected to the engine output member. A control unit is configured to selectively cause a device to resist or prevent rotation of the input member in response to the existence of certain conditions, such as the engine not supplying torque to the transmission and the transmission being in reverse operating mode. Resisting or preventing rotation of the input member improves transmission performance when only the motor/generators are supplying torque to propel the vehicle. A corresponding method is also provided.