Research On The Effects Of Intake And Fuel Injection Strategies On The Performance Of Boosted Downsized, High-Compression Ratio Sidi Engine

As worldwide energy and enviromental pressures increase,energy-saving and emission-reducing is driving more and more attentionfor all of the countries. A large amount of oil resources is consumed byautomotives every year, accompanied by higher greenhouse-gas emissions,so countries pay more and more attention to automotive’s fuel economy.Boosted downsing spark-ingintion direct-injection (SIDI) engine has beingbecame a promising technology and a vital research direction in manyautomotive companies, due to its better fuel economy, higher power output,and low CO2emissions. In order to further improve engine’s fuel ecomoy,a higher geometric compression ratio is favorable. However, highercompression ratio will lead to serious knocking combustion, which isconsidered as a key limitation factor for higher compression ratio operationin boosted gasoline engines. So, research on knock has imprortant socialand acedemic significance.A2.0L turbocharged SIDI engine configured with dual-independentvalve-varialbe-timing(VVT) is used in this paper. Knock supressionpotential by intake and fuel injection stragies is investigated in a boostedSIDI egines opeated with a higher geometric compression ratio. From thisstudy, it can be concluded that by combining VVT, bothlate-intake-valve-closing (LIVC) and early-intake-valve-closing (EIVC)can provide siginficant knock suppression performance, and compared to EIVC, a better knock peformacne is obseved for LIVC. In addition, doubleinjection is an effective strategy to supress knock, reduce soot emission,and improve cold start performance in boosted SIDI engine.