Comparison of performance of compact chamber spark-ignition engine with conventional SI engine

This paper deals with the compact chamber engine in which a bowl-like space in the piston or head of the cylinder is added to cause swirling of the air-fuel mixture. This causes a change in performance from the conventional spark ignition engine. In this work, the operating variables considered are the engine speed, equivalence ratio, inlet pressure and temperature and exhaust pressure. A computer program is specially devised to calculate performance at design and off design operation conditions. The compact chamber achieves an increase in volumetric efficiency of 5%. The brake efficiency is 28.5%, whereas for conventional SI engine is 23%, with an increase of 20%. The brake power for the compact chamber engine is 39 kW, whereas for the conventional engine is 35 kW, an increase of 10%. Hence, the reduction in the brake-specific fuel consumption is about 20%. Copyright (C) 2010 John Wiley & Sons, Ltd.