Effect of Ignition Advance Angle on Idle Performance of Hydrogen Fueled CNG Engine

Abstract

To study the effect of ignition advance angle(θi) on idle performance of a hydrogen fueled CNG engine,an idle performance test was conducted on a hydrogen fueled CNG engine.The engine speed was fixed at 800r/min;the excess air ratio was set at λ=2 and θi was adjusted from 20℃A BTDC to 0℃A BTDC.The results demonstrated that as θi was reduced,the flame development angle decreased and the rapid combustion period increased.When θi16℃A,most of the fuel was combusted before TDC;the negative power increased and the indicated thermal efficiency was rather low.When θi was around 10℃A,the indicated thermal efficiency reached its top value and the exhaust emissions were rather low.To a hydrogen fueled engine,the combustion conditions were not enough to produce certain amount of CO and HC under conditions of idle and lean burning;θi should be reduced properly to reduce NOx emissions.