Abstract: A method for controlling a hydrodynamic retarder in a motor vehicle that can be mechanically disengaged via a disconnect clutch, whereby at least one of the rotational speed of a revolving bladed rotor and the speed of a motor vehicle is monitored and a disconnect clutch is engaged below at least one of a pre-specified rotational speed of the revolving bladed rotor and a pre-specified speed of the motor vehicle, regardless of a request made by a driver assist system or by operation of an input device by the operator of the motor vehicle to turn on the hydrodynamic retarder.

Abstract: A sport running estimated value LEVELSP obtained by searching a value on a map prepared in advance based on an average values AGYAVE of lateral accelerations GY of a vehicle and on average values of vehicle speed changes is calculated, and a vehicle speed on a shift map is searched based on the sport running estimated value LEVELSP and an estimated value DA of a vehicle gradient, whereby a downshift vehicle speed VA at which a downshift is implemented is calculated. Then, the downshift is implemented in a case where actuation of a brake is detected, deceleration of the vehicle is a predetermined value or more, and a current vehicle speed is a downshift vehicle speed VA or more. In such a way, running on a meandering road, for which the downshift and a subsequent shift hold should be implemented, is sensed appropriately.

Abstract: The invention concerns a drive train, in particular of a motor vehicle fitted with a drive motor, including a main output shaft; having a transmission connected downstream of the drive motor in the drive power flow, comprising a transmission input shaft and a transmission housing; the transmission input shaft is connected to and actuated by the main output shaft of the drive motor or can be switched into such connection by means of a coupling; having a hydrodynamic retarder, comprising a driven bladed primary wheel and a stationary bladed secondary wheel or which is driven in reverse direction of the primary wheel, whereas both wheels form together a frusto-conical work space which is filled or can be filled with working medium, for hydrodynamic transmission of torque from the primary wheel to the secondary wheel; the drive motor includes an auxiliary output shaft, via which the primary wheel of the retarder is driven.

Abstract: The state of a fluid coupling in a motor vehicle powertrain is selectively controlled during neutral idle operation of the engine for increasing the engine temperature to a desired level. The fluid coupling includes an input member connected to the engine and an output member connected to the transmission, and the output member is selectively grounded under specified enable conditions to impose an engine load for raising the engine operating temperature. The output member is released to resume normal operation of the powertrain when the enable conditions are no longer met or an estimate of the fluid temperature in the coupling reaches or exceeds a predefined temperature.

Abstract: A hydrokinetic torque converter, particularly for use in the power train of a motor vehicle, has a housing which can receive torque from the prime mover of the vehicle and drives a pump adapted to rotate a turbine on the input shaft of the change-speed transmission. The turbine can also receive torque from the housing by way of a bypass clutch and a damper borne by a hub which is mounted on the input shaft. A feature of the invention resides in the simplicity of design and low cost of several component parts of the torque converter and in a novel mode of assembling the component parts.