STUDY OF PERFORMANCE AND COMBUSTION CHARACTERISTICS OF A STRATIFIED CHARGE SPARK IGNITION ENGINE

Abstract

The main target of developing the spark ignition engines is to reduce the hazard exhaust products emitted from these engines. It also aims to I increase their thermal efficiency which in turns require the increment of

compression ratio. The latter can't achieved in the conventional engines due to the abnormal combustion. There are man y ways to accomplish this ' I goa l s uch as applying the stratified charge technique. Among the techniques of stratification is the use of divided-chamber

system which fulfills to some degree the two basic requirements of I stratifi ed charge engines: (I) the inhibition of mi x ing prior to ignition to achieve stratification, and (2) rapid mixing just before combustion and I expans ion for complete combustion.

I Surveying of the available literature establishes the need for furthers research into the combustion characteristics of the st rat ified charge I engmes. The optimization of some of the controlling operating and design parameters are still a matter of controversy.

Therefore an experimental set-up was establ ished with the objective of I st uding the co mbustion process in divided-chamber strat ified charge engine by the injection of different fuels in the pre-chamber followed by oxygen injection with each type of the fuel s. therefore the study focused I on the effects of the degree of stratification, the pre-chamber volume, a nd the time of fuel and oxygen injection upon the engine performance and I combu sti on characteristics at di ff'erent compression ratios and speeds.