A Combustion Model for Analyzing the Effects of Natural Gas Composition on the Operation of a Spark Ignition Engine

The combustion of natural gas under lean premixed conditions is of current interest because it has properties that can lead to a potential decrease in pollutant formation and a high efficiency. The composition of the fuel mixture can vary depending upon its origin and can bring about significant changes in the combustion characteristics. This paper presents the experimental results of a single cylinder spark ignition engine fuelled with various natural gas compositions in lean mixture, and describes a numerical model that accounts for variations in concentrations of the fuel components. The diagnostic combustion model is based on the conventional one-zone approach. This thermodynamic analysis is coupled with a numerical resolution of energy and species conservation equations, which incorporates a detailed chemical kinetics. The numerical results demonstrate the influence of the fuel mixture composition on mass burn rates and burning velocities.