Characterizing Internal Combustion Engine Flows

This study characterizes internal combustion engine (ICE) valve flow efficiency, focusing on discharge coefficients. Combustion chamber fluid dynamics has a significant impact on engine indicated efficiency through its effect on combustion efficiency, duration, and discharge coefficients. This directly affects volumetric efficiency and thus maximum power. Characterizing this provides engineers with insight into potential modifications to the engine to improve efficiency. A GM 2.4L I4 LEA 4-Valve per Cylinder Ecotech engine's cylinder head was tested. Steady mass-flow-rate measurements for each port of the cylinder head were taken at various valve lifts and pressure drops via a Superflow-1020 flowbench, then compared to ideal flows by calculating the associated discharge coefficients. Differences in individual valve flow performance of the valve pairs were also evaluated for both the intake and exhaust. Future studies may include experiments with geometric modifications, injection methods, ignition methods, or fuels to further improve combustion efficiency. Increased efficiency of ICE engines lowers fuel usage and, in turn, contributes to lowering the rate of overall greenhouse gas emissions.