Numerical analysis of combustion parameters of a spark ignition engine fuelled with CNG and variable valve timing

Abstract

Spark ignition engines are still widely used in transport and natural gas could be a great alternative to conventional fuels. This article presents the combustion characteristics of natural gas at various engine speeds (2,000, 2,500 and 3,000 rpm) obtained by experiment and numerical simulations using AVL BOOST. The rate of heat release can be obtained from measured cylinder pressure curves. The influence of variable valve timing was determined by changing the angle of intake valve closing while the engine was running at the stoichiometric air-fuel mixture at fixed spark timing and the throttle angle.