There is provided a hydrodynamic retarder including a bladed rotor and a bladed stator jointly forming a working chamber to be filled with working medium and discharged therefrom, a working medium container receiving working medium, and a control pressure application system pressurizing the working medium with a control pressure medium to displace the working medium from the working medium container into the working chamber to set a desired braking torque. A centrifugal separator separating the working medium from the control pressure medium, the centrifugal separator is connected in a flow-conductive manner to an outlet of the working medium container for the control pressure medium to be pressurized with the control pressure medium, the centrifugal separator is driven by the pressure of the control pressure medium, and the working medium container is assembled from at least two shells, where the first and/or the second shell encloses the centrifugal separator.

A hydrodynamic retarder having a rotor and a stator or a rotor and an oppositely running rotor, which together form a toroidal working chamber to filled with working medium, in order to transmit a torque by means of a hydrodynamic working chamber working medium circuit. An external working medium circuit has a heat exchanger that discharges heat from the working medium. The external working medium circuit is connected by a working medium inlet and a working medium outlet to the working chamber. The working medium inlet and outlet open to the working chamber at a torus outer diameter of the working chamber. A working medium feed line opens into the external working medium circuit. A core ring filling line is connected in working-medium-conducting fashion to the working chamber. The core ring filling line opens into a core ring of the working chamber radially within the torus outer diameter.

A hydrodynamic retarder having a rotor and a stator or a rotor and an oppositely running rotor, which together form a toroidal working chamber to filled with working medium, in order to transmit a torque by means of a hydrodynamic working chamber working medium circuit. An external working medium circuit has a heat exchanger that discharges heat from the working medium. The external working medium circuit is connected by a working medium inlet and a working medium outlet to the working chamber. The working medium inlet and outlet open to the working chamber at a torus outer diameter of the working chamber. A working medium feed line opens into the external working medium circuit. A core ring filling line is connected in working-medium-conducting fashion to the working chamber. The core ring filling line opens into a core ring of the working chamber radially within the torus outer diameter.

A drive train has a hydrodynamic retarder including a rotating bladed rotor and bladed stator, forming a working chamber for hydrodynamic transmission of power from rotor to stator, a power input feeding drive power to the retarder, and a synchronized separating clutch connected between power input and rotor. The clutch has two clutch halves, friction elements contacting each other and mechanical blocking elements. The friction elements equalize rotational speed between clutch halves, and the blocking elements form-lockingly connect the clutch halves. The clutch has an actuator displaceable along a displacement travel, over a first distance bringing the friction elements into mutual contact, and a second distance adjoining the first distance to synchronize the friction elements and rotational speed for locking with the blocking elements. At least one displacement sensor directly or indirectly detects displacement travel by the actuator and/or position of the actuator on the displacement travel.

A drive train has a hydrodynamic retarder including a rotating bladed rotor and bladed stator, forming a working chamber for hydrodynamic transmission of power from rotor to stator, a power input feeding drive power to the retarder, and a synchronized separating clutch connected between power input and rotor. The clutch has two clutch halves, friction elements contacting each other and mechanical blocking elements. The friction elements equalize rotational speed between clutch halves, and the blocking elements form-lockingly connect the clutch halves. The clutch has an actuator displaceable along a displacement travel, over a first distance bringing the friction elements into mutual contact, and a second distance adjoining the first distance to synchronize the friction elements and rotational speed for locking with the blocking elements. At least one displacement sensor directly or indirectly detects displacement travel by the actuator and/or position of the actuator on the displacement travel.

A method for controlling a motor vehicle, comprising: retrieving road gradient data relating to an expected travelling route of the motor vehicle; based on at least the retrieved road gradient data and on a motor vehicle mass, simulating a required value of a braking power related variable, which required value is needed to prevent a vehicle speed from increasing above a preset desired vehicle speed in an upcoming downhill slope; determining an available value of the braking power related variable of at least one auxiliary brake of the motor vehicle; and based on the determined available value and the simulated required value of the braking power related variable, controlling the vehicle speed and/or at least one brake actuator of the motor vehicle such that the vehicle speed does not increase above the preset desired vehicle speed in the upcoming downhill slope.

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 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 coolant diverter system and method of controlling coolant flow are provided. The coolant diverter system includes a coolant diverter body having a coolant inlet opening, a driveline retarder outlet opening and a bypass outlet opening. The coolant diverter system also includes a valve positioned in the coolant diverter body. The valve is configured in a first valve orientation to fluidly couple the coolant inlet opening to the driveline retarder outlet opening in isolation from the bypass outlet opening. The valve is configured in a second valve orientation to fluidly couple the coolant inlet opening to the driveline retarder outlet opening and the bypass outlet opening. The coolant diverter system also includes a valve controller configured to place the valve in the first valve orientation in response to activation of a driveline retarder coupled to the driveline retarder outlet opening for braking.

A hydrodynamic retarder system for a vehicle is provided. In a first operational state with the vehicle powered on and a retarder deactivated, a pump directs fluid flow from a fluid sump to a retarder inlet valve in the closed position and directs fluid flow to a second sump. In a second operational state with the vehicle on and the retarder activated, the retarder inlet valve moves to the open position directing fluid flow into a retarder chamber and flowing out of the retarder chamber after filling a second volume and discharging to the second sump.