Heat losses minimization from hydrogen fueled 4-stroke spark ignition engines

Abstract

This paper presents an analytical study to minimize the heat lost during the power stroke of hydrogen-fueled, 4-stroke spark ignition engine. The effects of various design and operating parameters like engine speed, equivalence ratio, ignition timing, compression ratio and spark plug location on heat losses was studied. Then, the effect of heat loss on the engine's performance and emission characteristics was conducted with aim to minimize it. The study showed that the percentage heat loss decreased with increase in engine speed. Further, changing the compression ratio from 7 to 11 produced change of around 2-3% in percentage heat loss, while changing the spark plug location from periphery to center produced change of around 1-1.5% in percentage heat loss with maximum change occurring at lean mixtures. Changing the ignition timing from 50 to 10 degrees bTDC changed the percentage heat loss by more than 4%. As for the effect of percentage heat loss on the engine performance and emission characteristics, it was found that some of the heat must be allowed to be transferred from the cylinder to enhance the engine performance. This amount of heat loss varies with engine speed and equivalence ratio. It was found to be higher at higher engine speeds. Beyond this specific value, the engine performance and emission characteristics deteriorate. Copyright © 2007 by ABCM.