Investigation of Natural Gas Composition Effects on Knock Phenomenon in SI Gas Engines using Detailed Chemistry

Considering the growing role of natural gas as an alternative fuel in stationary and automobile engines and the differences in its composition, the influence of natural gas composition on knocking combustion in spark ignition gas engines is studied both experimentally and by employing detailed chemistry. A SI single cylinder gas engine with variable compression ratio has been used for experimental observations. The chemical scheme is embedded into a zero-dimensional model which employ three-zone approach. The scheme is used to simulate the post-flame heat release and pre-flame auto-ignition. The reactions in burning zone are modeled by chemical equilibrium calculations. The simulated results are in good agreement with the experimental observations.