Abstract
Keywords:
Gasoline engine, downsizing, knock, CFD.
Abstract
Today’s gasoline engine research focuses on further increasing the engine fuel efficiency, while maintaining the advantage of low emissions by use of three way catalysts. One promising solution is downsizing coupled with turbocharging where fuel-savings of up to about 20% seem feasible. However, this concept requires adequate knock control. The accurate knowledge of the conditions in the combustion chamber regarding species distribution and in-cylinder thermodynamic conditions is crucial in the understanding of the knock characteristics of an engine. However, this information is not easily obtained via experiments and can readily be extracted from numerical simulations. In the present paper, first an optimised chamber geometry is introduced for a multicylinder downsized engine which increases knock resistance. Then the in-cylinder conditions and knock are characterised for a small downsized single-cylinder engine by means of Computational Fluid Dynamics (CFD).