A cooling system in a vehicle includes a cooling fluid pump (3) that circulates cooling fluid in the cooling system, a cooler (5) for the cooling of the cooling fluid, and a valve (10) to lead cooling fluid to the cooler (5) for cooling or to a return line (13) without cooling. A first circuit (6) includes cooling channels (6a) for the cooling of the combustion engine (1) and a second circuit (17) for the cooling of a hydraulic retarder. The first circuit (6) leads cooling fluid from the cooling fluid pump (3) to a first inlet (10c) at the valve (10). The second circuit (17) leads cooling fluid to a second inlet (10d) at the valve (10). In operating conditions in which the hydraulic retarder is not activated, the valve (10) blocks the second inlet (10d) and thus the circulation of cooling fluid through the second circuit at the same time that it receives cooling fluid from the first circuit (6) through the first inlet (10c).

Systems and methods for providing an improved strategy for controlling a variable speed water pump in a vehicle. In some embodiments, more than one water pump speed function is calculated based on values obtained from vehicle sensors, and a controller chooses among the water pump speed function results to set a water pump speed. In some embodiments, the water pump speed is increased when driveline torque is greater than a threshold amount for an amount of time that varies based on the driveline torque. In some embodiments, ambient temperature is considered while determining whether the water pump should provide full coolant flow to an auxiliary coolant loop of a trailer.

A method for filling a hydraulic system with a hydraulic fluid includes sealing the hydraulic system in a pressure-tight manner and recording a pressure in the sealed hydraulic system, filling or removing a predefined volume of the hydraulic fluid from the sealed hydraulic system, recording a pressure in the sealed hydraulic system after the filling or removing, calculating a volume of a total residual air in the hydraulic system depending on the pressures before and after the filling or removal of the predefined volume, calculating a final correction volume depending on the volume and a design-specified air feed of the hydraulic system, and refilling or removing the calculated final correction volume to achieve a final correct filling quantity for the hydraulic system.

A cooling circuit for a motor vehicle having a cooling medium pump that circulates a cooling medium in the cooling circuit having a hydrodynamic retarder. The cooling circuit further includes a main circuit in which the cooling medium pump and a drive motor of the motor vehicle, as well as a heat exchanger are positioned. A secondary branch of the cooling circuit includes a feed that branches off from the main circuit at a branch-off point and ends in the hydrodynamic retarder, and a return which proceeds from the hydrodynamic retarder and ends at a junction location in the main circuit. The return ends upstream of the branch-off location of the feed as viewed in a flow direction of the cooling medium in the main circuit, however on the same side of the cooling medium pump or at the branch-off location of the feed in the main circuit.

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 cooling-fan control device for a vehicle that increases the cooling capacity of a cooling oil that cools a brake rapidly and inhibits a brake damage in a case where the brake is applied during traveling or, in addition to the above-described problem-to-be-resolved, suppresses engine horsepower consumption and avoids consumption increase, while increasing the cooling capacity of the brake cooling oil. The rotation speed of the cooling fan is controlled to obtain the higher target rotation speed of a first target rotation speed corresponding to a detected cooling oil temperature and a second target rotation speed corresponding to a detected brake operation amount. The present invention is applicable to a vehicle in which an engine power is distributed to a travel power train and a hydraulic pump, drive wheels are operated via the travel power train, and the cooling fan is actuated via the hydraulic pump.