Abstract: A method of adapting the characteristic curve of clutches in a partial dual-clutch transmission of a vehicle, for example a utility vehicle, having a first partial transmission in the form of a dual-clutch transmission (DKG) having a dual clutch (DK) that includes a first clutch (K1) and a second clutch (K2), which can be functionally connected to a drive engine (M), and a second partial transmission in the form of a main transmission (HG) which shifts with traction force interruption and which is arranged downstream from the dual-clutch transmission (DKG) in a drive-train. To achieve reliable and precise clutch control and a consistently high level of shifting comfort, the characteristic curve adaptation of the first and the second clutches (K1, K2) is carried out with the assistance of a pre-loading of the first and the second clutches (K1, K2), while the main transmission (HG) is in a neutral position.

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 hydraulic control system for a dual clutch transmission includes a plurality of solenoids and valves in fluid communication with a plurality of clutch actuators and with a plurality of synchronizer actuators. The clutch actuators are operable to actuate a plurality of torque transmitting devices and the synchronizer actuators are operable to actuate a plurality of synchronizer assemblies. Selective activation of combinations of the solenoids allows for a pressurized fluid to activate at least one of the clutch actuators and synchronizer actuators in order to shift the transmission into a desired gear ratio.

Abstract: A method for shifting a transmission capable of operating in a hydrostatic power transmission mode or a blended hydrostatic and mechanical power transmission mode is provided. The transmission includes a mechanical portion and a hydraulic portion. The method comprises the steps of placing the transmission in the hydrostatic power transmission mode, reducing an amount of engagement of a primary clutch, adjusting a rotational speed of the hydraulic portion, increasing an amount of engagement of a secondary clutch, and engaging the secondary clutch and disengaging the primary clutch.

Abstract: A rear-wheel drive system includes motors for generating driving force to drive a vehicle, hydraulic brakes on power transmission lines between the motors and rear wheels switching a motors side and a wheels side to a connected state or a disconnected state, an ECU controlling the motors and the brakes and a one-way clutch in parallel with the hydraulic brakes on the transmission line configured to be engaged when a forward rotational power on the motors side is inputted into the wheels side and disengaged when a backward rotational power on the motors side is inputted into the wheels side and vice versa. The ECU causes the hydraulic brakes to be applied so as to put the motors side and the wheels side in the connected state when the forward rotational power on the motors side is inputted into the wheels side.

Abstract: A method for improving starting of an engine that may be repeatedly stopped and started is presented. In one example, the method adjusts a desired engine speed to at least two levels during engine speed run-up from cranking to engine idle speed. The method may improve vehicle launch for stop/start vehicles.

Abstract: When a predetermined time has passed without detection of engine stall and without detection of the neutral state and without detection of a vehicle starting operation, in a first control state in which a clutch is in a disengaged state, a clutch control system effects transition to a second control state in which transition to a third control state is permitted. When a vehicle starting operation is detected in the second control state B in which the clutch is in the disengaged state, a liquid pressure modulator is driven to effect transition to the third control state in which the clutch is put in the engaged state or a partially engaged state. When an engine stall or the neutral state is detected in the second control state, transition to the first control state A is effected.

Abstract: A fail-to-neutral diagnostic technique for a transmission that includes a variator may include monitoring a state of a pressure differential valve fluidly coupled to a high side pressure applied to at least one actuator coupled to at least one corresponding roller of the variator and also fluidly coupled to a low side pressure applied to the at least one actuator, determining from the state of the pressure differential valve a variator torque sign corresponding to whether torque transferred by the at least one roller is positive or negative, determining an expected variator torque sign based on current operating conditions of the transmission, and commanding the transmission to a true neutral condition if the determined variator torque sign is different from the expected variator torque sign.

Abstract: A hybrid driving force transmission device includes an engine (E), a motor-clutch unit (MC), and a transmission unit (T). The motor-clutch unit (MC) is coupled to the engine (E), and includes a multi-plate dry clutch (7) and a slave cylinder (8). The transmission unit (T) is coupled to the motor-clutch unit (MC), and includes a transmission housing (41), a V-belt type continuously variable transmission mechanism (42), and an oil pump (OP). A cylinder housing (81) which comprises a first clutch pressure oil passage (85) communicating with the slave cylinder (8) is provided in the motor-clutch unit (MC). By coupling the motor-clutch unit (MC), a second clutch pressure oil passage (47) is brought into communication with the first clutch pressure oil passage (85) in the cylinder housing (81). An end plate (45) having the second clutch pressure oil passage (47) is provided in the transmission unit (T).

Abstract: A control system and method for controlling a multiple gear ratio automatic transmission in a powertrain for an automatic transmission having pressure activated friction torque elements to effect gear ratio upshifts. The friction torque elements are synchronously engaged and released during a torque phase of an upshift event as torque from a torque source is increased while allowing the off-going friction elements to slip, followed by an inertia phase during which torque from a torque source is modulated. A perceptible transmission output torque reduction during an upshift is avoided. Measured torque values are used during a torque phase of the upshift to correct an estimated oncoming friction element target torque so that transient torque disturbances at an oncoming clutch are avoided and torque transients at the output shaft are reduced.

Abstract: A method and control module for controlling a transmission of a vehicle includes a clutch torque load predictor module generating a predicted clutch torque load signal for the shift command and a minimum clutch pressure module generating a minimum clutch pressure signal corresponding to a minimum clutch pressure. The control module includes a pressure command module generating a commanded clutch pressure signal for the predicted clutch torque load signal based on the minimum clutch pressure signal and commanding operation of a clutch with a commanded clutch pressure signal. The control module also includes a transmission control module generating the shift command after the clutch torque load predictor module generates the predicted clutch signal, the minimum clutch pressure module generates the minimum clutch pressure signal and the pressure command module generates the commanded clutch pressure signal.

Abstract: A drive train of a motor vehicle with an internal combustion engine, a torque converter and a transmission, wherein a separation clutch is provided between the internal combustion engine and the torque converter. In order to be able to perform a creeping process at a certain creeping velocity, the separation clutch is operated slipping. This way, the gearing of the startup process can be configured long, even when using a so-called hard torque converter, without having to tolerate a creeping velocity, which is too high.

Abstract: There is provided a drive device for a vehicle. A forward clutch that is engaged during forward driving is provided in a power transmission path between an engine and a drive wheel. A spring is incorporated in an engagement oil chamber of the forward clutch, thereby causing the forward clutch to be held in a slipping state or an engaged state through the spring force even during an idling stop that suffers from reduced control oil pressure. This arrangement can prevent the forward clutch from producing an engagement shock during an engine restart. In addition, an input clutch driven by an electric actuator is provided in the power transmission path. With this arrangement, neutral control can be performed by disengaging the input clutch even if the forward clutch which is to be held in a slipping state or an engaged state is provided.

Abstract: A control system for a dual clutch transmission (DCT) of a vehicle comprises a difference module, a summer module, and a position control module. The difference module determines a difference between a desired position for a gear actuator and a measurement of a current position of the gear actuator. The summer module determines a sum of a derivative of the difference and a product of the difference and a predetermined gain. The position control module controls the current position of the gear actuator based on the sum. The current position of the gear actuator controls a position of a gear synchronizer that slides along an output shaft of the DCT. The position of the gear synchronizer controls coupling of a gear ratio with the output shaft.

Abstract: A construction vehicle includes a control unit configured to shift gear after performing pre-shifting to couple a target speed-change gear that corresponds to a target speed with a target speed-change shaft in non-transmitting state of rotation of the input shaft when the gear shift is performed from a current speed to the target speed, in a state in which the current speed gear that corresponds to the current speed step and the current speed-change shaft that corresponds to the current speed gear are coupled. When the vehicle speed detected by the vehicle speed detecting section is zero, the control unit is configured to perform pre-shift auxiliary control prior to the pre-shifting control to input the rotation of the input shaft to the target speed-change shaft in a state in which the target speed-change shaft is not coupled to the plurality of speed-change gears.

Abstract: A control device provided with a first map capable of performing coast down control of altering a transmission ratio of a continuously variable transmission at a time of deceleration of a vehicle has a second map which is set by making a lock-up release vehicle speed for releasing a lock-up clutch and an engine rotation frequency correspond to each other, wherein, when cost down control is performed, the second map is used to set a lock-up release vehicle speed for releasing the lock-up clutch.

Abstract: A gearshift controller for an industrial vehicle, includes: a speed ratio detection unit that detects a speed ratio of speeds of an input axis and of an output axis of a torque converter; a gearshift control unit that shifts up a speed stage when the detected speed ratio is equal to or more than a first predetermined value and shifts down the speed stage when the detected speed ratio is equal to or less than a second predetermined value, which is smaller than the first predetermined value; and an operation member with which a downshift to the first speed is instructed by operation thereof by an operator. When the downshift is instructed by the operation member, the gearshift control unit controls the speed stage to be kept at the first speed for a predetermined time period regardless of the speed ratio detected by the speed ratio detection unit.

Abstract: A powertrain system includes a transmission operative to transfer power between an engine coupled to an input member and a plurality of torque machines and an output member, A method for controlling the powertrain system includes monitoring system operation and determining an output torque request, determining a closed loop speed error, determining motor torque offsets to the torque machines based upon the closed loop speed error, determining output torque constraints based upon the motor torque offsets and the system operation, determining an output torque command based upon the output torque request and the output torque constraints, determining preferred motor torque commands for the torque machines based upon the output torque command, reducing the preferred motor torque commands for the torque machines using the motor torque offsets to the torque machines, and adjusting the reduced preferred motor torque commands for the torque machines based upon the closed loop speed error.

Abstract: A clutch control system for a vehicle includes a shift command module and an offgoing clutch control module. The shift command module commands an upshift of a clutch-to-clutch transmission when an engine torque is less than a predetermined negative torque. The offgoing clutch control module increases an offgoing clutch pressure above a predetermined apply pressure in response to the command. An offgoing clutch is fully engaged when the offgoing clutch pressure is greater than the predetermined apply pressure.

Abstract: A method for controlling shift process in dual-clutch gearbox having dual-clutch gearbox input shaft connected to a drive engine, having two friction clutches and two partial gearboxes, comprising detecting demand for a shift from source gear into target gear, the source gear and target gear assigned to first partial gearbox; opening friction clutch assigned to first partial gearbox and closing friction clutch assigned to other partial gearbox to transmit drive power via intermediate gear of other partial gearbox; disengaging source gear and temporarily conducting a pressure-exertion process in friction clutch assigned to the first partial gearbox before engagement of target gear, with rotational speed of first partial gearbox being reduced due to the pressure-exerting operation according to drag torque, opening friction clutch assigned to other partial gearbox and closing friction clutch assigned to first partial gearbox to transfer drive power to the target gear without an interruption in tractive force.

Abstract: A system and method for providing TCC control and/or transmission gear shift control by considering the rate of change of the accelerator pedal or throttle position. The method determines whether the rate of change of the throttle position exceeds a predetermined positive rate of change or a predetermined negative rate of change and, if so, releases the TCC to provide TCC control. Alternatively, or additionally, the method can provide a transmission gear down-shift or up-shift depending on which direction the throttle position is changing. Once the TCC and/or gear shift control has been initiated, the method can start a timer and then return to normal TCC and/or gear shift control after the timer has expired. The TCC and/or gear shift control can also return to normal if the rate of change of the throttle position indicates that the throttle is being returned to its previous position.

Abstract: A method of clutch control includes engaging a first holding clutch to place the transmission in a first neutral mode and predicting a first EVT mode. The method begins tracking a first output clutch and predicts a second EVT mode. Tracking the first output clutch ends and tracking a second holding clutch begins. The method engages the second holding clutch to place the transmission in a second neutral mode, ending tracking of the second holding clutch. The first holding clutch is disengaged to place the transmission in a third neutral mode and the method begins tracking a second output clutch. Engaging the second output clutch places the transmission in the second EVT mode and ends tracking of the second output clutch. The engine may be placed into a speed control mode and the transmission placed into a full hydraulic neutral mode.

Abstract: A clutch engagement control system for a vehicle transmission. The system comprises an automatic transmission gearset and at least one hydraulic clutch coupled to the gearset. A hydraulic pressure controller is coupled to the clutch. A clutch engagement controller is coupled to the pressure controller, and an altitude sensor is coupled to the clutch engagement controller. The clutch engagement controller is configured to receive from the altitude sensor an altitude signal corresponding to the altitude of the vehicle. The clutch engagement controller adjusts a hydraulic pressure request of the pressure controller in accordance with the altitude signal, such that the clutch engages with at least one of a rate and pressure corresponding to the sensed altitude. A method employs the system.

Abstract: A hydraulic control system for a dual clutch transmission includes a plurality of solenoids and valves in fluid communication with a plurality of clutch actuators and with a plurality of synchronizer actuators. The clutch actuators are operable to actuate a plurality of torque transmitting devices and the synchronizer actuators are operable to actuate a plurality of synchronizer assemblies. Selective activation of combinations of the solenoids allows for a pressurized fluid to activate at least one of the clutch actuators and synchronizer actuators in order to shift the transmission into a desired gear ratio.

Abstract: A vehicle automatic speed change power transmission control includes a control arrangement with overshoot/undershoot protection logic. The control is used with an electro-hydraulic pressure control module featuring a linear solenoid, and which supplies a hydraulically-actuated clutch configured to effect gear changes. The overshoot/undershoot protection logic is configured to detect when a commanded increase/decrease clutch pressure satisfies a clutch pressure threshold and to then activate the protection logic. Once the protection logic is activated, large command pressures increases/decreases are implemented in a series of stages having variable gains. The first stage has an aggressive gain and achieves 50-80% of the commanded clutch pressure. The second stage has a reduced gain and achieves 90% of the commanded clutch pressure. The third stage has a still further reduced gain and achieves about 100% of the commanded clutch pressure.

Abstract: A method of operating a drivetrain of a motor vehicle. The drivetrain comprises a transmission arranged between a drive assembly and an axle drive, such that an input shaft of the transmission is connected, via a controllable separator clutch, to the drive assembly and an output shaft of the transmission is connected to the axle drive, and such that the transmission comprises at least one shifting element formed as a claw clutch. To reduce the probability that a tooth-on-tooth position may occur in a shifting element formed as a claw clutch, a torque is applied thereto by at least one transmission-internal assembly and/or at least one transmission-external assembly so that a speed difference at the claw clutch approaches a predetermined nominal value, and engagement of the claw clutch is only started when the speed difference of the claw clutch reaches the nominal value.

Abstract: A control apparatus for an automatic transmission includes a stepwise variable transmission mechanism; a power ON/OFF state judging section; and a shift control section configured to control the stepwise variable transmission mechanism to a target rotational speed by disengaging the first engagement portion and engaging the second engagement portion in accordance with a torque inputted to the stepwise variable transmission mechanism, the shift control section being configured to engage one of the first engagement portion and the second engagement portion which has a function to suppress a variation of an input rotational speed of the stepwise variable transmission mechanism which is generated by a switching of the power ON/OFF state when the power ON/OFF state is switched at the shift control of the stepwise variable transmission mechanism, and to disengage the other of the first engagement portion and the second engagement portion.

Abstract: A vehicle drive unit includes a clutch pressure control valve that controls hydraulic pressure for operating the clutch; a clutch control valve that is provided in a first oil passage between the clutch pressure control valve and the clutch, and that controls hydraulic pressure in an engagement state between full engagement and disengagement of the clutch; a second oil passage that bypasses the clutch control valve and that is arranged parallel to the first oil passage; and a shift valve that connects, to an oil passage connected to the clutch, the first oil passage when controlling the engagement state between full engagement and disengagement of the clutch, and the second oil passage when not controlling the engagement state between full engagement and disengagement of the clutch.

Abstract: A method of monitoring a hydraulic or pneumatic transmission control system, which comprises a pressure supply unit with a conduit directing a pressure medium under a supply pressure, and an actuating member for a clutch control element of a friction clutch. The actuating member has a pressure space which can be connected by a clutch control valve to the conduit, and in which the supply pressure is determined by a pressure sensor that can be connected to the conduit. The method includes the steps of determining the supply pressure by the pressure sensor, given that briefly opening the clutch control valve produces a pressure increase and/or a pressure gradient of the control pressure in the pressure space, and the currently existing supply pressure can be calculated from the control pressure, the pressure increase and/or the pressure gradient.

Abstract: A method and system for executing a shift from a first fixed gear to a second fixed gear in a powertrain system comprising a two-mode, compound-split, electro-mechanical transmission operative to receive a speed input from an engine is described. It includes deactivating an off-going clutch, and generating a time-based profile for rotational speed of an oncoming clutch. The input speed is controlled based upon the rotational speed of the oncoming clutch and an output of the transmission. The oncoming clutch is actuated, preferably when the input speed is synchronized with a rotational speed of an output shaft of the transmission multiplied by a gear ratio of the second fixed gear, preferably after a predetermined elapsed period of time in the range of 500 milliseconds.

Abstract: A transmission clutch control device that can perform adequate connection-disconnection control of a transmission clutch, regardless of disturbances such as variations in battery voltage and temperature variations. There are included a linear solenoid valve 31 that is provided in a pipe for supplying an oil pressure to a transmission clutch 3 and has an opening degree changing correspondingly to a supplied current value, a drive circuit C that changes a supplied current value that is supplied to the linear solenoid valve 31 in response to an inputted drive signal, control means 22 for storing a group of target drive signals So that are inputted to the drive circuit C when the transmission clutch 3 is connected and disconnected, and a sensor that detects a value Ir of a real supplied current flowing in the linear solenoid 31.

Abstract: A force transmission device having a hydrodynamic component, disposed between an input and an output, comprising at least a pump shell and a turbine shell, forming an operating cavity in combination, with an actuatable clutch device for at least partially bridging the hydrodynamic component, comprising a clutch component for at least partially bridging the hydrodynamic component, comprising a first clutch component connected with the input and a second clutch component at least indirectly connected to the output, which can be brought into operative engagement with one another through an actuation device, with a vibration absorber disposed in the force flow at least subsequent to the actuatable clutch device, with a housing coupled with the input or with an element coupled non-rotatably to the input and coupled with the pump shell.

Abstract: “Threshold A is substituted in a power-on state, “threshold B”, which is lower than “threshold A”, is substituted in a power-off state, and “threshold C”, which is lower than “threshold B” is substituted during a brake operation, as a rapid deceleration determination threshold. The rotational speed of an output shaft of an automatic transmission and the rapid deceleration determination threshold are compared to determine whether a vehicle is rapidly decelerating. The engagement state of a lock-up clutch is controlled based on whether the vehicle is rapidly decelerating.

Abstract: A drive train of a motor vehicle with an internal combustion engine, a torque converter and a transmission, wherein a separation clutch is provided between the internal combustion engine and the torque converter. In order to be able to perform a creeping process at a certain creeping velocity, the separation clutch is operated slipping. This way, the gearing of the startup process can be configured long, even when using a so-called hard torque converter, without having to tolerate a creeping velocity, which is too high.

Abstract: A method and a device for controlling starting, driving and shifting processes of a motor vehicle with a drive motor (2) and a gearshift (6), which can be brought into effective drive connection with one another using a starting and shifting clutch (4), with a clutch actuation device (25, 26) as well as with a control apparatus (13) which stands in connection with a power element of the same for controlling the power of the drive motor (2), and which is connected using signal engineering with sensors (14, 17, 19, 21) which ascertain an accelerator deflection angle (A), a motor rotational speed (C) and a transmission input shaft rotational speed (E).

Abstract: A method for controlling a transmission input clutch during a vehicle launch includes selecting a subject device that transmits torque between an input and an output, a providing a mathematical model of the subject device, such that the model employing only static relationships of engine speed and transmission input speed to a desired magnitude of torque produced by the subject device, using the model, the current engine speed and the current engine speed to determine the desired torque produced by the subject device, and adjusting the torque capacity of the clutch to the desired torque of the subject device determined from the model.

Abstract: A transmission system having a plurality of gear ratios, a selector assembly for selectively engaging the gear ratios, and a control system arranged to measure the amount of deformation caused by torque in the transmission system in at least one static component or assembly that is deformed due to torque in the transmission system, wherein the control system is arranged to measure deformation and to adjust the torque in the transmission system according to the measured deformation and a known relationship between the gear ratios, wherein the transmission system is arranged such that selection of a new gear ratio occurs almost instantaneously without substantial power interruption.

Abstract: A method for controlling an input clutch of a vehicle transmission that includes an output driveably connected to the input clutch includes increasing the torque capacity of the input clutch, determining a reference acceleration of the output, determining a current acceleration of the output after the reference acceleration is determined, if a difference between the reference acceleration of the output and the current acceleration of the output is equal to or greater than a reference change in acceleration of the output, determining a desired input clutch torque, and adjusting the input clutch to produce the desired input clutch torque.

Abstract: A vehicle drive unit is provided which includes a hydraulic circuit capable of efficiently supplying a hydraulic pressure from an accumulator to a hydraulic servo while minimizing the capacity of the accumulator. In a hydraulic circuit included in a continuously variable transmission, an accumulator is connected through an electromagnetic switch valve to an oil passage connecting a clutch pressure control valve and a manual valve, a one-way valve for allowing oil to flow only in the direction from the clutch pressure control valve toward the accumulator and the forward clutch is provided in the oil passage. The electromagnetic switch valve switches an oil passage to a communicating state when the oil pump is driven and switches the oil passage to a shut-off state when the oil pump is stopped.

Abstract: The control apparatus includes a so-called pre-shift means. The pre-shift means operates a predetermined synchromesh based on a result of prediction by a predicting means. It thereby couples together a transmission input shaft with which a friction transfer mechanism having not been used for achievement of a current gear position and a transmission output shaft through a predetermined gear train and brings them into standby state. As the timing with which the synchromesh coupling operation by the standby control is started, the time when it is determined that the friction transfer mechanism having not been used for the achievement of the current gear position has been disengaged is taken regardless of the completion of the achievement of the current gear position.

Abstract: A vehicle automatic speed change power transmission control includes a control arrangement with overshoot/undershoot protection logic. The control is used with an electro-hydraulic pressure control module featuring a linear solenoid, and which supplies a hydraulically-actuated clutch configured to effect gear changes. The overshoot/undershoot protection logic is configured to detect when a commanded increase/decrease clutch pressure satisfies a clutch pressure threshold and to then activate the protection logic. Once the protection logic is activated, large command pressures increases/decreases are implemented in a series of stages having variable gains. The first stage has an aggressive gain and achieves 50-80% of the commanded clutch pressure. The second stage has a reduced gain and achieves 90% of the commanded clutch pressure. The third stage has a still further reduced gain and achieves about 100% of the commanded clutch pressure.

Abstract: “Threshold A is substituted in a power-on state, “threshold B”, which is lower than “threshold A”, is substituted in a power-off state, and “threshold C”, which is lower than “threshold B” is substituted during a brake operation, as a rapid deceleration determination threshold. The rotational speed of an output shaft of an automatic transmission and the rapid deceleration determination threshold are compared to determine whether a vehicle is rapidly decelerating. The engagement state of a lock-up clutch is controlled based on whether the vehicle is rapidly decelerating.

Abstract: A control apparatus for a vehicle that decreases shift shock generated by full engagement of a clutch at completion of an inertia phase. The apparatus includes a driving source, a step automatic transmission arranged to attain a predetermined shift stage by engagement of frictional engagement elements, a rotational speed control to control the driving source so that an input rotational speed of the transmission becomes a predetermined target value during the inertia phase, a torque control to control the driving source so that the input torque of the transmission becomes a predetermined target value during the non-inertia phase, and a torque correction to correct the engagement torque of the engagement element or the input torque of the transmission so that the engagement torque of the engagement element before completion of the inertia phase is substantially identical to the input torque of the transmission after completion of the inertia phase.

Abstract: A method for clutch disengagement at idling running of a vehicle including an automated manual transmission is characterized in that a rate of the clutch disengagement is controlled responsive to a brake pedal force applied to a brake pedal by a vehicle operator. A clutch disengagement controller controls a rate of clutch disengagement at engine idling running mode. The clutch disengagement controller is connected to a brake pedal sensor sensing a force applied to a brake pedal and to at least one air inlet valve controlling a position of a clutch cylinder. The controller controls opening of said at least one air inlet valve responsive to the force sensed by the brake pedal sensor.

Abstract: A power transmission device includes an actuator having an electric motor driving a pump to supply pressurized fluid to a piston acting on a friction clutch to transfer torque between rotatable input and output members. In one instance, a valve between the pump outlet and the piston selectively traps pressurized fluid acting on the piston without continued energization of the electric motor. A gerotor may be formed from a material having a first coefficient of thermal expansion and a housing formed from a material having a second lower coefficient of thermal expansion to vary pump component clearances as the viscosity of the pumped fluid changes with changes in temperature. A method of controlling the power transmission device includes defining a correlation between pump speed, fluid temperature and fluid pressure, determining fluid temperature, determining pump speed, and rotating the pump to transfer a predetermined quantity of torque.

Abstract: A power train of a motor vehicle with a drive motor (2), a transmission (4) with variable transmission ratios connected to an axle drive (5), and an automatic motor clutch. The automatic motor clutch is a passively lockable friction clutch actuated by a spring-loaded pressing device (6) and whose transferable rotational toque (coupling torquet) is adjusted using a clutch actuator (7), and is located in the flow of power between the drive motor (2) and the transmission (4). Improved controllability and a more rapid response of the motor clutch (3) is achieved by the spring-supported pressing device (6) to produce a basic coupling torque below the maximum rotational torque of the drive motor (2) and, a second pressing device (17) regulates a higher coupling torque by way of an effective connection with the clutch actuator (7).

Abstract: In a method for setting the clutch torque of a clutch, especially a clutch disposed in a drive train of a motor vehicle, the clutch is adjusted using a clutch actuator. This clutch actuator has at least two actuator parts that may be positioned relative to each other at raster values of a position raster. A position setpoint corresponding to a clutch torque and disposed between the raster values of the position raster is calculated, and the actuator parts are positioned relative to each other at a raster value of the position raster that is adjacent to the position setpoint. In addition to the first position raster value, a second position raster value is calculated in such a manner that the position setpoint is disposed between the first position raster value and the second position raster value.

Abstract: The invention concerns a method of controlling a twin-clutch transmission (10). When the torque transmitted in a first transmission path (C1, E2, Z8, Z9, S2, Z3, Z4) reaches an upper limit given by the torque transmission capacity of that path further additional torque produced by an engine at the drive shaft (I) is transmitted by closure of the second clutch (C2) to the output shaft (O) in parallel relationship by way of a second transmission path (C2, E1, Z1, Z2, S1, Z3, Z4). That permits the output of the engine to be better utilised and makes it possible to achieve better travel characteristics.

Abstract: A more efficient method for maintaining the hydraulic actuation of a selectively engageable torque transmitting device in a vehicle. The method includes generating a predetermined pressure level of a hydraulic fluid such as, for example, with a pump. The pressurized hydraulic fluid is transferred through an open valve and to a selectively engageable torque transmitting device such that the selectively engageable torque transmitting device is engaged. Thereafter, the valve is closed so that the predetermined pressure level of hydraulic fluid at the selectively engageable torque transmitting device remains relatively constant. Accordingly, the selectively engageable torque transmitting device remains engaged without continuously generating additional pressure such that the fuel economy of the vehicle is improved. A corresponding apparatus is also provided.

Abstract: A differential limiting control apparatus for a vehicle has: clutch unit interposed between one rotational shaft and the other rotational shaft for variably transmitting a driving force between the one rotational shaft and the other rotational shaft; target differential speed setting unit for setting a target differential speed between the one rotational shaft and the other rotational shaft, actual differential speed detecting unit for detecting an actual differential speed between the one rotational shaft and the other rotational shaft, and clutch torque computing unit for computing an engagement force of the clutch unit by obtaining a deviation between the target differential speed and the actual differential speed, configuring a switching function by using at least a polarity related to an integral term of the deviation, and applying a sliding mode control.