A controllable hydrodynamic retarder system for a transmission including an electronic controller unit (ECU) for selecting and controlling brake torque by adjusting a retarder outlet pressure is described. The system can include an algorithm to calculate a retarder outlet pressure set point or tables or brake torque curves or profiles to allow the ECU to calculate or look up the functional relationships between the retarder RT outlet pressure, a vehicle or rotor speed, and a brake torque curve selected by the operator to provide the selected RT outlet pressure. The systems disclosed can also include a cooling system or utilize a vehicles engine cooling system. In one embodiment, the cooler can be shared between a transmission and the controllable retarder and can be adjusted to accommodate cooling requirements. The ECU can also make adjustments to the RT outlet pressure to address short term and long term RT overheating protection independent of the cooling system.

A method for controlling a separating clutch in a power train of a vehicle having a drive motor and a retarder. The clutch is arranged such that a rotor of the retarder is switched into a drive connection with the motor and/or power train via the clutch and a working chamber of the retarder can be filled with an operating medium to build up a braking power such that braking torque is exerted by the retarder onto the power train and/or motor. A control system switches the clutch into a closed or an open position. The switching of the clutch into the closed position occurs depending on an input signal to the controller, and the clutch is switched back into the open position depending on essentially no medium being present in the working chamber of the retarder and that predetermined limits of an operating and/or environmental parameter are not exceeded.

A method for controlling a separating clutch in a power train of a vehicle having a drive motor and a retarder. The clutch is arranged such that a rotor of the retarder is switched into a drive connection with the motor and/or power train via the clutch and a working chamber of the retarder can be filled with an operating medium to build up a braking power such that braking torque is exerted by the retarder onto the power train and/or motor. A control system switches the clutch into a closed or an open position. The switching of the clutch into the closed position occurs depending on an input signal to the controller, and the clutch is switched back into the open position depending on essentially no medium being present in the working chamber of the retarder and that predetermined limits of an operating and/or environmental parameter are not exceeded.

A hydraulic cylinder retarder includes a hydraulic cylinder mechanism, a hydraulic oil conveying mechanism and a hydraulic oil valve mechanism. A piston component of the hydraulic cylinder mechanism is connected to a transmission device. Resistance to the piston movement of the hydraulic cylinder mechanism is generated by the hydraulic oil conveying mechanism and the hydraulic oil valve mechanism, so as to reduce the operation speed of the transmission device.

A hydraulic cylinder retarder includes a hydraulic cylinder mechanism, a hydraulic oil conveying mechanism and a hydraulic oil valve mechanism. A piston component of the hydraulic cylinder mechanism is connected to a transmission device. Resistance to the piston movement of the hydraulic cylinder mechanism is generated by the hydraulic oil conveying mechanism and the hydraulic oil valve mechanism, so as to reduce the operation speed of the transmission device.

Disclosed herein is an electric brake system including: a hydraulic feeder configured to move a piston forward or backward according to a pedal effort from a brake pedal to discharge oil; a motor position sensor configured to measure a position of the piston; and a controller configured to control, when an Anti-lock Brake System (ABS) control starts, a change in direction of the piston based on predicted displacement information of the piston while the ABS control is performed such that the piston is at a target position at target vehicle speed.

Disclosed herein is an electric brake system including: a hydraulic feeder configured to move a piston forward or backward according to a pedal effort from a brake pedal to discharge oil; a motor position sensor configured to measure a position of the piston; and a controller configured to control, when an Anti-lock Brake System (ABS) control starts, a change in direction of the piston based on predicted displacement information of the piston while the ABS control is performed such that the piston is at a target position at target vehicle speed.

A method of operating a drive-train (1) of a motor vehicle, which has a drive aggregate (2), a transmission (3) with a hydrodynamic torque converter (4), an engine brake device (6) and a drive output (5). The engine brake device (6) which is activated when the drive-train (1) is operating in an overdrive mode, during a coasting process, before carrying out an overdrive downshift, when the turbine rotational speed (n_tu) of the torque converter (4) is lower than the engine idling rotational speed (n_mot_LL) of the drive aggregate (2). The engine brake device (6) is deactivated at a point in time chosen such that, when the overdrive downshift is carried out, a load change in the drive-train (1) is avoided.

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.

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.