A Study on Performance Improvement of Natural Gas Engine

Natural gas possesses several characteristics that make it desirable as an engine fuel; 1)lower production cost, 2)abundant commodity and 3)leaner energy source than gasoline.

Due to the physical characteristics of natural gas, the volumetric efficiency and flame speed of a natural gas engine are lower than those of a gasoline engine, which results in a power loss of 10-20% when compared to a normal gasoline engine.

This paper describes the results of a research to improve the performance of a natural gas engine through the modification and controls of compression ratio, air/fuel ratio, spark advance and supercharging. It emphasizes how to improve the power characteristics of a natural gas engine. Combustion characteristics are also studied using an ion probe. The ion probe is applied to measure flame speed of gasoline and methane fuels.