A Study on Effect of Injection Pressure on Performance and Emissions of Port-Injected Natural Gas Engine

This paper presented the effect of port fuel injection pressure on performance and emission characteristics of a natural gas SI engine. The research method carried out in this study is experiment on a single-cylinder diesel engine converted into a research CNG engine. The injection pressure was varied of 3 bars and 4 bars, at different engine speeds (1032 rpm, 1205 rpm, 1408 rpm, 1609 rpm and 1829 rpm). The experimental results indicated that injection pressure has a significant effect on engine power, torque and exhaust emissions. Increasing injection pressure from 3 to 4 bars will improve power and torque at all speeds. CO, HC and NOx emissions are reduced when the engine operates at higher speeds.