The Effect of In-Cylinder Water Injection Direction on Combustion Characteristics in Lean-Burn SI Engine

Abstract

In this paper, the effect of in-cylinder water injection from intake and exhaust port side on combustion characteristics was compared in lean burn SI engine. The engine bench test at a compression ratio of 17 and excess air ratio of 2.0 shows that indicated thermal efficiency with intake side water injection is higher than that with exhaust side injection at water injection timing (SOIw) = -180 deg.ATDC. At SOIw = -90 deg.ATDC, on the other hand, indicated thermal efficiency in both injection cases is comparable and combustion duration with exhaust side injection is shortened than that with intake side injection.