小排量直喷增压汽油机喷水技术应用研究

汽油机喷水技术通过向燃烧室内喷水降低发动机爆震倾向,降低燃油消耗并改善排放,近年来逐渐成为新研究热点。首先对喷水器的喷雾特性进行了试验研究,并利用CFD仿真分析方法在某1.5L直喷涡轮增压发动机上设计了进气道喷水方案,最后开展了3000r/min@1.4MPa和5500r/minWOT工况下的台架试验研究。研究结果表明:汽油机采用喷水技术可以有效抑制爆震,改善燃油经济性。在高速大负荷工况,喷水可取代燃油加浓策略来降低排气温度,实现当量比燃烧。

Water Injection Technology of Small Displacement Direct Injection Turbocharged Gasoline Engine

The technology of water injection for gasoline engine has become a new research hotspot in recent years because spraying water into combustion chamber can reduce knock tendency and improve fuel economy and emissions.The spray characteristics of water injector were first studied through the experiment,the scheme of water injection inside the intake port was designed with CFD method based on a 1.5 L TGDI engine,and the bench test was finally conducted at 3 000 r/min with 1.4 MPa and 5 500 r/min with WOT.The results show that the water injection can reduce knock and improve fuel economy effectively.Water injection can decrease the exhaust temperature and realize the equivalent-ratio combustion instead of rich fuel strategy under the conditions of high speed and high load.