Influence of single injection and two-stagnation injection strategy on thermodynamic process and performance of a turbocharged direct-injection spark-ignition engine fuelled with ethanol and gasoline blend

A comparative investigation was conducted on a turbocharged direct-injection spark-ignition engine fuelled with gasoline and ethanol blend. Influences of single injection (SI) and two-stagnation injection strategy (TSIS) on thermodynamic process and performance of the engine operated on part-load condition were discussed and compared in this paper. The results indicated that 50% combustion position was slightly shifted to TDC and 10-90% combustion duration was shortened by using TSIS modes as compared with SI mode. However, the coefficient of variation in the indicated mean effective pressure was significantly increased with the second injection fuel mass repartition. In addition, the brake thermal efficiency (BTE) and brake specific fuel consumption (BSFC) were increase by adopting the TSIS modes, but the increase amplitude of BTE and BSFC was decreased, and even deteriorated in TSIS 6 mode. In comparison with SI mode, Hydrocarbon and carbon monoxide were declined with advanced second injection timing while both of them increased with increasing second injection fuel mass repartition. Moreover, NOx emissions were dramatically reduced by utilizing TSIS modes. Eventually, CO2 emission was mainly related to the carbon atom content, combustion efficiency and heat-work conversion in-cylinder.