Parameter study of common rail pressure for low octane gasoline multiple premixed compression ignition (MPCI) in light-duty diesel engine

A novel combustion concept called ‘multiple premixed compression ignition’ in the gasoline direct injection compression ignition regime is proposed. Its predominant feature is the first premixed and subsequent quasi-premixed combustion processes in a sequence of ‘spray–combustion–spray-combustion’ around the compression top dead center. The multiple-stage premixed combustion decouples the pressure rise from the pollutants formation process, which means the pressure rise rate and emissions can be reduced simultaneously, while achieving a high thermal efficiency. The experimental study of the multiple premixed compression ignition mode has been carried out in a single cylinder research engine retrofitted from a light-duty diesel engine with a compression ratio of 18.5. Low octane gasoline with the research octane number of 66 was tested under 1400 r/min, 0.8 MPa indicated mean effective pressure conditions, without exhaust gas recirculation or intake conditioning. A parameter study of common rail pressure w...