Effects of LPG on the performance and emission characteristics of SI engine - An Overview

IC engines are considered as major contributors to the deterioration of the environment, therefore there is an increasing demand to go for alternative fuels for both SI and CI engine so as to maintain the ecological balance as well as reduce dependency on petroleum and socio economic aspects. The gaseous fuel such as LPG has been widely used throughout the world in SI engines as it impacts greenhouse emissions less than any other fossil fuel. Many researchers have carried out large number of studies on LPG fueled in SI engine and it was reported that the use of LPG has a significant effect on emission control and engine performance. In the studies carried out it was found that the concentration level of CO, HC and CO2 were on the lower side for LPG as compared to gasoline for the same power output, but the concentration of Nox for the same power output was higher for LPG than gasoline. SI engine fueled with LPG resulted in a decrease in power output and volumetric efficiency as compared to gasoline and the specific fuel consumption for LPG, values slightly higher than gasoline. This paper presents a general overview about the previous research efforts into SI engine using LPG as an alternative fuel for the purpose of improving emission characteristics and engine performance.