Development of an LPG Injection System for SI Engines

Abstract

Recently, in the context of increasing global energy demand and environmental problems, many researchers have proposed effective solutions for transportation in the current situation. Liquefied petroleum gas (LPG) has been considered as a preferred alternative fuel for spark-ignition (SI) engines. This study describes the development of an LPG injection system for an SI engine. The proposed system was based on the analysis of fuel requirement and metering for the engine operating with LPG, as well as the effect of engine parameters on the LPG flow rate. The system cooperates with the gasoline ECU to produce the signals controlling LPG injectors. An experiment was conducted with an SI engine under different conditions of loads and engine speeds. Experimental results showed that the LPG injection system adapted all test conditions, the engine ran smoothly at all test speeds and partial opening throttle. Fueling with LPG, engine torque and energy conversion efficiency were higher, whereas exhaust gas emissions such as HC, CO, and NOx were lower compared with that as fueled with gasoline.