Impact of a split injection strategy on mixing, ignition and combustion behavior in Premixed charge compression ignition combustion

Mixing, ignition and combustion behavior in a rapid compression expansion machine operated under Premixed Charge Compression Ignition (PCCI) relevant conditions are investigated by combined passive optical laser-optical high-speed diagnostics. The PCCI concept is realized using split injection schedule consisting of long base load two closely separated short injections near top dead center. Previous studies close-coupled double constant ambient showed an increased penetration rate the subsequent fuel spray. However, aerodynamic gain from preceding counteracted density rise during stroke transient engine conditions. study confirms that mixing spray significantly increased. Regarding behavior, thermodynamic analysis exhibits contributions low temperature oxidation reactions more than 20 % to total heat release, with notable amount unburnt mass varying 25 61 %. data reveals multi-dimensional impact changes operating parameters on local mixture field dynamics. onset reactivity first found be dominated strategy, while location strongly related state. Low consecutive promoted, when upstream sustained. Likewise, it shown high accelerated entrainment persistent reactivity.