Optimization of Injection Parameters in Compressed Natural Gas Direct Injection (CNG-DI) Spark Ignition Engine

Energy security and environmental problems boosts the development on automotive industry. CNG as an alternative fuel has been applied in the vehicle to reduce the engine emissions with drawback in engine performance. It has lower performance compared to gasoline due to lower volumetric efficiency, lower energy content, and longer combustion durations. However, high octane number of CNG is beneficial in increasing engine efficiency. Direct injection application on CNG engine is expected to increase the volumetric efficiency of the engine to get further increase in engine performance while still maintaining the low engine emissions. In order to improve the engine performance, the objectives of this research are investigating the combustion characteristics of CNG direct injection engine and optimization of injection parameters to obtain high performance engine