缸内直喷LNG发动机工作过程的数值模拟

Simulation of working pocess of LNG direct-injection engine

以一台4气门车用汽油机改装的缸内直喷LNG发动机为研究对象,应用STAR-CD软件建立了缸内直喷LNG发动机工作过程的计算模型,对其工作过程进行了数值模拟,并分析了缸内直喷LNG发动机工作过程中缸内流场的动态特性及其温度场、压力场的变化.结果表明,在进气过程,进气道和气缸内会出现强烈的湍流运动;随着进气过程的持续,缸内压力会变得均匀;燃烧过程中,气缸内局部会出现温度过高.

Taking a LNG direct-injection engine converted from a four-valve gasoline engine vehicle as the study object, a numerical simulation of working process for a LNG direct-injection engine was carried out by using computational fluid dynamics software STAR - CD. The dynamic characteristics for flow, temperature and pressure fields, and emission in the working process were analyzed. Calculation results show that the perplexing turbulence around the inlet valve and cylinder during the inlet process can lead to energy losses. With the inlet process continuing, the cylinder pressure will become uniform. The partial hyperpyrexia can be caused in cylinder during the combustion process.