A SIMULATION STUDY ON COMBUSTION CHARACTERISTICS OF A SPARK IGNITION ENGINE WITH DIFFERENT FUELS: GASOLINE, LPG, CNG, AND BIOGAS

Abstract

This paper presents a simulation investigation of the combustion characteristics, performance, and emission of a spark ignition engine fueled with gasoline,
liquified petroleum gas (LPG), compressed natural gas (CNG), and biogas. The simulation was conducted on the advanced software AVL Boost. The engine model
was customed with different fuels in the simulation, but the air excess ratio (λ) was kept the same at 1.0. The difference in fuel properties contributed to a later
combustion process for LPG, CNG, and biogas-fueled engines. The peak in-cylinder pressure was 77.7; 62.9; 68.9 and 32.2bar for gasoline, LPG, CNG, and biogas.
The study's results indicated that the test engine's brake power decreased by up to 22.63; 17.22; and 39.10% on average for LPG, CNG, and biogas. However, the
brake-specific energy consumption (BSEC) increased by 5.50 and 8.12% when fueled by LPG and CNG; and reduced by 27.4% for the bioag-fueled engine.
Nevertheless, the exhaust emissions of the test engine that is powered by gaseous fuels significantly decreased. NOx emissions decrease by 45.04; 56.75 and
66.75% on average for LPG, CNG, and biogas fuel. The average CO level of the engine when fueling with LPG, CNG, and biogas was reduced by 91.44; 90.51 and
93.01%. The HC emission of the engine that LPG and CNG powered is considerably lower than that of the original engine, in turn, 73.72% and 69.29% on average,
while a reduction of 39.22% was observed for biogas-fueled engines on average.