SOURCES OF HEAT REJECTION IN A HDDI DIESEL ENGINE AND METHODS TO IMPROVE THERMAL EFFICIENCY
educational resourceposted on 10.06.2019, 18:59 by Kyle Michael Palmer
In the realm of class 8 trucking, fuel economy and emissions compliance are becoming the driving force for development of new heavy-duty direct injected (HDDI) diesel engine technologies. Current production engines in this class convert around 40% of the fuels energy into usable work while the unused potential transfers to the environment as excess heat energy. Current OEMs are working toward decreasing this heat loss and improve engine efficiency and emissions. Quantifying the energy lost by component and system highlights the areas that demand the most attention. By studying test cell data of heat rejection on a production Cummins ISX engine and using the data to calibrate an engine model for the simulation software GT-Suite, heat rejection values and the components which transfer the energy are exposed. The simulation software provides energy transfer by both system and component type. The results reveal that 10% of engine total heat rejection (THR) is transferred through the cylinder wall to the engine coolant system. When the heat imparted on the cylinder wall is broken up by component, the piston rings contribute nearly as much heat into the liner as the combustion gas.