Amir-Hasan Kakaee - School of Automotive Engineering, Iran University of Science and Technology, Tehran, Iran
Majid Karimi - School of Automotive Engineering, Iran University of Science and Technology, Tehran, Iran

Natural gas is the cleanest fossil fuel and it has high energy conversionefficiencies for power generation in internal combustion engines. Naturalgases have varying composition depending on the place where they areproduced. This paper studies the effects of natural gas composition on thecombustion and emissions characteristics of CNG engines and presents theoverall combustion characteristics obtained from running a ۱.۶۵ L, ۴-cylinderEF ۷ CNG engine. Engine power, Torque, BMEP and BSFC were measuredunder steady state operation conditions at full load conditions. The obtainedsimulation results were compared with experimental ones in the literature andshowed that the CNG composition had a considerable influence on engineperformance and fuel economy. A correlation has been proposed to help gaininsight into the relationship between the Methane Number (MN) and enginepower, and it provides a practical method for estimating the engine powerwhen the composition of natural gases varies.

Natural gas composition, CNG engine, Combustion, Power, Emissions, Methane number