The feasibility of the calculation model and calculation methods is verified by engine bench test and visual rapid compression machine (RCM) test as reported in this paper. Using AVL software FIRE, the processes of low speed preignition (LSPI) and super knock triggered by the oil particles have been studied by numerical analysis of downsized turbocharged direct injection (DI) engines with different proportions of ethanol-gasoline blended fuel and different operating conditions (1200 r·min⁻¹, 1600 r·min⁻¹). The results show that the E10 and E20 fuel engines produce super knock successively; with the increase of the ethanol proportion, even if the LSPI phenomenon (1200 r·min⁻¹) still occurs and leads to the subsequent knock process, the pressure rise amplitude is obviously reduced, and no super knock phenomenon occurs at the time when the ethanol proportion reaches 30%; there is no LSPI phenomenon in the engine after the blending rate is above 50%. The overall conclusion is that there must be LSPI before the super knock in ethanol-gasoline blended fuel downsized turbocharged DI engines, but the LSPI not always lead to super knock. With the increase of ethanol proportion, even if the LSPI occurs in the engine cylinder, it only causes regular knock.

中文翻译：

---

乙醇汽油混合气的小型涡轮增压直喷发动机低速点火和爆震过程的数值分析

本文通过发动机台架试验和视觉快速压缩机（RCM）试验验证了该计算模型和计算方法的可行性。使用AVL软件FIRE，通过对不同比例的乙醇汽油混合燃料和不同工况的小型涡轮增压直喷（DI）发动机进行数值分析，研究了由油粒引发的低速提前点火（LSPI）和超爆震的过程。 （1200r·min ^-1，1600r ·min ^-1）。结果表明，E10和E20燃油发动机先后产生超爆震。即使LSPI现象（1200 r·min ^-1）仍然发生并导致随后的爆震过程，压力上升幅度明显减小，当乙醇比例达到30％时没有发生超爆震现象; 混合比例大于50％后，发动机内无LSPI现象。总的结论是，在乙醇汽油混合燃料小型涡轮增压DI发动机的超级爆震之前必须有LSPI，但是LSPI并不总是导致超级爆震。随着乙醇比例的增加，即使LSPI出现在发动机气缸中，也只会引起规律的爆震。