Performance, emissions and exergy analysis of a HCCI engine working with two different research octane number fuels

Abstract

Homogeneous Charge Compression Ignition (HCCI) is one of the candidates of combustion modes that promise the world an efficient combustion process as compared to the conventional. In this study, the combustion characteristics and exhaust gas emissions rate of a gasoline engine working on HCCI mode are experimentally investigated using a single-cylinder, four strokes, and water cooled research engine. The engine tests are performed with two different research octane number (RON) fuels: gasoline 95 and gasoline 98. The variations of the brake specific fuel consumption (BSFC), the exhaust gas emissions and the exhaust gas temperature with the engine load represented by the indicated mean effective pressure (IMEP) are compared for both fuels. In addition, in-cylinder pressure, heat release rate, energetic and exergetic efficiencies, exhaust exergy rate, heat transfer exergy rate and destruction exergy rate are compared. It was found that BSFC, exhaust gas emissions (except CO) and exhaust gas temperature were lower with gasoline 95. The heat release rates and its peak were obtained to be higher with gasoline 95. No effects on energetic efficiency, exergetic efficiency and exhaust exergy destruction were found. However, exhaust exergy rate and heat transfer exergy rate were found to be affected by fuel octane number.