The characteristics of gasoline engines with the use of LPG: An experimental and numerical study

Abstract

This paper presents an experimental and numerical study of the effect of using liquefied petroleum gas (LPG) in place of gasoline on spark-ignition engine characteristics, including performance, combustion, and emissions. The four-stroke, single-cylinder, TE200 engine capable of developing 2.5 kW at 3600 rpm has been modified to run on LPG fuel under variable speed and load conditions. The numerical analysis is performed with the help of the Diesel-RK simulation software. A parametric study of the effect of changing the compression ratio and ignition time on engine performance and emissions was numerically studied. Experiments are conducted with two modes (Gasoline and LPG) under loads of (0, 25, 50, 75 and 100)% in terms of brake power and different speeds (2400, 3000, 3600) rpm. The experimental findings revealed that the use of LPG reduced brake thermal efficiency (BTE) by 4.52%, and improved brake specific fuel consumption (BSFC) by 5.42% compared to gasoline. The volumetric efficiency decreased by 4.65%. Significant reduction in the emissions of carbon dioxide (CO2) and carbon monoxide (CO) 14.4% and 11.54% respectively. The NOₓ emissions increased when using LPG fuel. The numerical results compared to the situation of gasoline fuel, showed that the peak pressure and heat release increased. An earlier combustion starting occurrence and closer to the top dead center (TDC) is noticed compared to gasoline. The cylinder temperature and the burnt exhaust gas temperature increased by 14.9%, 7.8%, respectively. The results also showed an improvement in BSFC by (2.1%), and a decrease in BTE and ηᵥ by (1%, 5.93%) respectively. NOₓ emissions increased when using LPG by (8%). Both experimental and numerical results validated with the results of other researchers' work and good convergence captured.

Keywords

• LPG
• Spark ignition (SI)
• Gasoline
• Performance characteristics
• Combustion