| NUMERICAL ANALYSIS OF LOW SPEED PRE-IGNITION AND KNOCK PROCESS IN DOWNSIZED TURBOCHARGED DIRECT INJECTION ENGINES WITH ETHANOL-GASOLINE BLENDS |
| Li Ruichen1, Xu Boyan1, Qi Yunliang2, Xu Weiyang1 |
1Shandong Jianzhu University
2Tsinghua University |
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| ABSTRACT |
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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. |
| Key Words:
Low speed pre-ignition, Super knock, Ethanol-gasoline blended fuel, Numerical analysis, Downsized turbocharged direct injection engines |
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Corresponding Author.
Xu Boyan , Email. 
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