喷雾-壁面复合引导直喷汽油机燃烧过程的数值解析

The Numerical Analysis on Combustion for a Spray-Wall Complex Guided Gasoline DI Engine

采用分层稀薄燃烧技术的缸内直喷汽油机因其显著的节油效果,成为当前研究的热点。缸内直喷汽油机实现分层稀薄燃烧的主要问题在于混合气浓度场分布不合理造成局部燃烧恶化进而影响发动机的燃烧效率和排放水平。因此本文采用本课题组提出的喷雾-壁面复合引导燃烧系统,使用AVL-FIRE软件对直喷汽油机的分层稀薄燃烧过程进行了数值解析。结果表明:部分负荷工况下喷射提前角在40°CA BTDC时,在20°CA BTDC缸内可形成较好的分层混合气;在696°CA点火放热率峰值最大,而CO和NO的排放随着点火提前角的减小而减小。

Using stratified combustion technology in gasoline direct- injection（ GDI） has become a research hotspot,because of its remarkable energy saving benefits. The main problem of stratified lean combustion in gasoline direct- injection is that the mixture of the concentration field distribution is not reasonable,which causes the deterioration of local combustion and the combustion efficiency and emission level of the engine. So this paper uses the Spray- wall complex guided combustion system proposed by our research group,using FIRE- AVL software to simulate the stratified lean combustion of the direct injection gasoline engine and the numerical analysis of the combustion process. The results show that when the injection advance angle is 40°CA BTDC,the better stratified mixed gas can be formed in the 20°CA BTDC cylinder,and the heat release rate peak at 696°CA is maximum,while the emission of CO and NO decreases with the decrease of the ignition advance angle.