Abstract

In this paper, a mathematical model is performed in order to analyze the effect of the methane number (MN) on knock tendency when spark ignition internal combustion engine operate with gaseous fuels produced from different thermochemical processes. The model was validated with experimental data reported in literature and the results were satisfactory. A general correlation for estimating the autoignition time of gaseous fuels in function of cylinder temperature, and pressure, equivalence ratio and methane number of the fuel was carried out. Livengood and Wu correlation is used to predict autoignition in function of the crank angle. This criterium is a way to predict the autoignition tendency of a fuel/air mixture under engine conditions and consider the ignition delay. A chemical equilibrium model which considers 98 chemical species was used in this research in order to simulate the combustion of the gaseous fuels at differents engine operating conditions. The effect of spark advance, equivalence ratio, methane number (MN), charge (inlet pressure) and inlet temperature (manifold temperature) on engine knocking is evaluated. This work, explore the feasibility of using syngas with low methane number as fuel for commercial internal combustion engines