A method for operating a motor vehicle includes, when a target differential speed is set for a separating clutch (4), determining a power transmission factor depending on the target differential speed and an internal combustion engine-driven torque to be transmitted by the separating clutch (4). The method also includes determining an actuating pressure for the separating clutch (4) depending on the power transmission factor, controlling the separating clutch (4) with the actuating pressure, ascertaining an actual differential speed forming at the separating clutch (4) depending on the actuating pressure, determining a corrected power transmission factor with a controller (10) depending on a deviation between the target differential speed and the actual differential speed, determining a corrected actuating pressure for the separating clutch (4) depending on the corrected power transmission factor and the internal combustion engine-driven torque to be transmitted, and controlling the separating clutch (4) with the corrected actuating pressure.

A method for operating a hybrid drive train of a motor vehicle (X) which has a combustion engine (VM), a transmission (G), an electric machine (EM), as well as a separation clutch (KO) positioned between the combustion engine (VM) and the electric machine (EM). During a purely electric drive operation in which the separation clutch (KO) is disengaged and, when a gear is selected in the transmission (G), and during expectation, reaching, or exceeding a rotational speed difference of the separation clutch (KO) is larger or equal to a limit value, and/or in an expectation, reaching, or exceeding a rotational speed limit of the electric machine (EM), the separation clutch (KO) is engaged. Further, an electronic control unit (ECU) executes the method and a motor vehicle (X) having such an electronic control unit (ECU).

A vehicle start control method includes: a condition determination step of determining, by a controller, whether or not it is necessary to control an engine torque in addition to a slip control of a clutch when a vehicle has started moving; and an engine control step of controlling, by the controller, the engine torque according to an engine error revolutions per minute (RPM) which is a difference between a target engine RPM and an actually measured engine RPM, when it is necessary to control the engine torque in addition to the slip control of the clutch.

A method for operating a drive train of a motor vehicle may include, for a starting process of an internal combustion engine, transferring the separating clutch from a disengaged condition into an engaged condition or a slip state such that the electric machine accelerates the internal combustion engine to a starting speed. The method may further include actuating a torque-transmitting element between the electric machine and the output shaft to enter a slip state. The method may also include increasing the torque of the electric machine to reliably reach and hold the slip state of the torque-transmitting element. Additionally, the method may include operating the electric machine as a generator or as a motor depending on an expected load direction of the drive train during the starting process to reliably reach and hold the torque-transmitting element in the slip state.

A transmission includes an input shaft coupled to a prime mover, a countershaft, main shaft, and an output shaft, with gears between the countershaft and the main shaft. A shift actuator selectively couples the input shaft to the main shaft by rotatably coupling gears between the countershaft and the main shaft. The shift actuator is mounted on an exterior wall of a housing including the countershaft and the main shaft. An integrated actuator housing includes a single external power access for the shift actuator. A controller interprets controls the shift actuator with actuating and opposing pulses, and interprets a shaft displacement angle, determines if the transmission is in an imminent zero or zero torque region, and performs a transmission operation in response to the transmission in the imminent zero or zero torque region.

A vehicle control apparatus includes an engine, a refrigerant compressor, a lock up clutch, a throttle valve, and first, second, and third deceleration controllers. The second deceleration controller controls the lock up clutch to a slip state and controls the throttle valve openwise on the condition that the refrigerant compressor is in the stopped state on decelerated travel of a vehicle in a second speed region in which a vehicle speed is lower than a first vehicle speed and higher than a second vehicle speed lower than the first vehicle speed. The second deceleration controller controls the lock up clutch to a disengaged state and controls the throttle valve closewise on the condition that the refrigerant compressor is in the operative state on the decelerated travel of the vehicle in the second speed region.

A fail-safe method for a parallel hybrid electric vehicle, having a motor connected between an engine and a transmission, and an engine clutch connected between the engine and the motor, includes: operating the engine using a starter and engaging the engine clutch; switching a first gearing map, which determines a change in a gear ratio of the transmission depending on a throttle vale opening rate regulated by an accelerator pedal and a vehicle speed obtained, to a second gearing map, which allows the gear ratio to change at a higher vehicle speed than that before the motor system failure occurs; and assisting a driving power of a first battery consumed by a low voltage DC-DC converter (LDC) with a counter electromotive power of the motor generated during operating of the engine in an engaged state of the engine clutch.

A vehicle start control method includes: a condition determination step of determining, by a controller, whether or not it is necessary to control an engine torque in addition to a slip control of a clutch when a vehicle has started moving; and an engine control step of controlling, by the controller, the engine torque according to an engine error revolutions per minute (RPM) which is a difference between a target engine RPM and an actually measured engine RPM, when it is necessary to control the engine torque in addition to the slip control of the clutch.

Systems and methods for operating a driveline of a hybrid vehicle are described. In one example, vehicle launch is controlled according to a linear quadratic regulator that provides feedback control according to torque converter slip error and vehicle speed error. The vehicle launch is also controlled according to feed forward control that is based on requested torque converter slip and requested vehicle speed.

A method for operating a drive train of a motor vehicle includes, for a starting process according to a first operating strategy, completely engaging a torque converter lockup clutch (WK) and, according to a second operating strategy, not completely engaging the torque converter lockup clutch (WK). A hydraulic pressure gradient for filling a piston chamber of the torque converter lockup clutch (WK) is selected to be higher upon selection of the first operating strategy than upon selection of the second operating strategy. A drive train module of a motor vehicle includes a control unit (5) for controlling, by way of an open-loop control system, the method.