通过台架试验的方法，基于一台1.5 L涡轮增压直喷汽油机，应用连续可变气门升程（CVVL）技术，在一定程度上实现米勒循环效果。在此基础上，对泵气损失、机械损失、理论热效率、米勒循环与LP-EGR的关系进行研究，提出优化方案并进行分析。试验结果显示，使用CVVL技术实现了米勒循环效果，泵气损失及机械损失均有一定降低，燃烧效率提高，但油耗降幅不明显。增大发动机压缩比，匹配LP-EGR系统，EGR降低油耗的作用非常明显，米勒循环的作用相对弱化，EGR对于发动机的充气能力要求增强，导致米勒度有一定的降低。

The Miller cycle effect was achieved with continuous variable valve lift (CVVL) on a 1.5L turbocharged direct injection gasoline engine through bench test. The pumping loss, mechanical loss, theoretical thermal efficiency, and the relationship between Miller cycle and LP-EGR were further studied and the optimized scheme was proposed and analyzed. The experimental results show that the CVVL technology realizes the Miller cycle effect, the pumping loss and mechanical loss reduce to a certain extent, the combustion efficiency improves, but the fuel consumption reduction is not obvious. By increasing the compression ratio of engine and matching the LP-EGR system, the effect of EGR on fuel consumption reduction becomes obvious and the Miller cycle effect relatively weakens. The EGR requirement of engine aeration-enhancing ability results in a certain decrease of Miller degree.