Document Type : Original Article
Department of Mechanical Engineering, Babol Noshirvani University of Technology, Babol, Iran
For decreasing the fuel consumption of internal combustion engines, and also reducing the emissions, investigation of the effective parameters on power, emissions, and the combustion phasing is important. In this study, the influence of adding water to a Reactivity Controlled Compression Ignition (RCCI) engine has been numerically investigated. For this purpose, water with different mass fractions was added to the air-fuel mixture. In order to simulate the engine, AVL Fire software was used. The results show that substituting a portion of gasoline fuel with water, up to 10% mass fraction, raises the combustion chamber pressure. In this condition, the production of hydroxyl free radicals, as one of the characteristics for the start of combustion, occurs earlier. Furthermore, Indicated Mean Effective Pressure (IMEP) remains unchanged. By further increasing the water mass the production of hydroxyl radical decreases, and the high-temperature heat release is delayed; also comparing to when water was not added, average temperature of the combustion chamber reduces, while the amount of CO production does not change. Increasing the number of water moles increases the maximum in-cylinder pressures so that compared to pure gasoline mode, by replacing 20% of gasoline mass with water, the indicated mean effective pressure approximately stays the same.