A study on the characteristics of mixture formation and combustion in a PCCI engine using an early multiple injection strategy

Premixed diesel engines have the potential to achieve a more homogeneous and leaner mixture, closer to TDC, than conventional diesel engines. Early studies have shown that in a Premixed Charge Compression Ignition (PCCI) engine, the fuel injection timing and spray angle affect the mixture formation and combustion. The purpose of this study was to investigate the effect of injection timing and a fuel supply system using a narrow angle injector called Narrow Angle Direct Injection (NADI) on combustion and mixture formations. In the case of single injection, at 100° injection angle and 65° injection timing, the mixture became more homogeneous so that the characteristics of IMEP and smoke were better than others. And as the injection times increased, the evaporated fuel percentage increased as well, so we could get higher IMEP and still low smoke characteristics. From this study, we found that the fuel injection timing affects the mixture formation, which in turn affects combustion in the PCCI engine and multiple injections have better effects on combustion because of the higher evaporation rate.