Effects of Water Injection on Performance and Exhaust Emissions of SI Engine with Y2O3-Coated Piston

Abstract

One of the most critical pollutant emissions in spark ignition (SI) engines is hydrocarbon (HC) emissions, which are partially incomplete combustion products. In this study, the upper surface of a piston was covered with ceramic material with a high heat reserve in order to reduce HC emissions from SI engines and to increase engine performance. However, when the upper surface of the piston was coated with a high heat reserve material, NOx emissions released from the engine especially under full load conditions increased compared with the standard case, due to increased temperatures inside the cylinder. Water was injected into the intake manifold to control NOx emissions. As a result of the experimental studies carried out, it was found out that in the thermal barrier–layer engine there was a 3.5% increase in effective power and a 4.9% decrease in specific fuel consumption compared with the standard case. HC emissions decreased by 36% and NOx emissions increased by 11.1%. When water injection was applied to the engine, HC emissions decreased by 43% and NOx emissions decreased by as much as 24.8% compared with the standard engine data. Engine performance parameters improved by 3.44% compared with the standard case.