Effects of port and direct injection conditions on spatial-temporal combustion processes and emissions characteristics in PCCI combustion

It has been well-known that mixture distribution condition affects much on combustion and emissions characteristics of premixed charge compression ignition (PCCI). In response, the authors have developed a novel control technique of fuel spray characteristics utilizing flash boiling of mixed fuels in order to achieve operation range expansion and emissions reduction in the PCCI engine. To develop the effective use of them, the present study explores the relation between the mixture distribution condition, and combustion and emissions characteristics. The experiments were conducted using a single cylinder compression ignition engine and an optically accessible one, equipped with port and direct injection systems which are capable of setting a wide variety of mixture distribution condition. The results developed an understanding of the effect of the rich and lean mixture on the combustion processes and emissions. In addition, those for two primary reference fuels were compared in order to know the influences of fuel chemical character.