氢内燃机怠速性能试验研究

Idle Characteristics of a Hydrogen Fueled SI Engine

为研究氢内燃机的怠速特性,在一台6缸氢内燃机上研究了过量空气系数λ与点火提前角θi对发动机主要性能参数的影响.结果表明:随着λ的增大,最大指示热效率ηi所对应的θi逐步增加,ηi随之增加,NOx排放随之减小;同一λ条件下,NOx排放随着θi增大而增加;氢内燃机怠速时可采用λ>2.5的稀混合气,且应适当增大Qi;最大缸压随着λ增加而降低、随着θi增大而上升;不同λ值条件下最大压力升高率的规律基本相似,只是在λ=2.5、θi<10°CA时,最大压力升高率基本保持不变。

This paper investigates the effect of the excess air ratio λ and ignition advance angle θi on idle characteristics of a turbocharged hydrogen fueled SI engine.The experimental data are conducted under various operating conditions including different λ and θi.It is found that the ignition advance angle at MBT point gradully increases with increasing excess air ratio from 1.1 to 2.5.The indicated thermal efficiency increases as λ increases.NOx emission decreases as λ increases.When λ is kept constant,NOx emission increases as θi increases.During idle conditions of a hydrogen fueled engine,a lean mixture with a λ more than 2.5 is suitable,and θi should increase appropriately.The maximum cylinder pressure increases with an increase of λ and θi.The trend of the maximum rate of pressure rise is similar at different λ.Only under the conditions of λ=2.5 and θi〈10°CA,the maximum pressure rise rate remains almost unchanged.