Abstract: A turbocompound engine having a power turbine bypass valve and a control module for controlling opening and closing of the bypass valve. The turbocompound engine is capable of operating in a compression braking mode, and the control module opens the bypass valve in response to actuation of the compression braking, resulting in improved braking.

Abstract: The disclosure illustrates a cooling system for a turbocharged diesel engine having an aftercooler and an oil cooler. The cooling system is defined by two flow loops, one for the engine and the other for cooling purposes. An engine driven pump circulates a coolant through the engine block and cylinder heads. The pump also circulates coolant through the cooling loop which includes the engine oil cooler immediately upstream of a radiator and bypass line. The aftercooler is downstream of the radiator and bypass line. Placement of the oil cooler ahead of the radiator and bypass line produces a higher temperature potential which permits a reduction in radiator size in addition to other benefits. A flow control logic system embodied in a dual thermostat arrangement ahead of the radiator and bypass line minimizes mixing of bypass flow with radiator flow and reduces radiator flow rates to permit low aftercooler temperatures that hithertofore have not been achievable.