Experimental investigation on the effect of mixed additives on homogeneous charge compression ignition combustion

The experimental research of homogeneous charge compression ignition (HCCI) combustion process with mixed additives was carried out by the modified fourth cylinder of a four-cylinder diesel engine. The influence of mixed additives on the HCCI combustion process was investigated. Experimental results indicate that the mixed additives are better than the single additive for HCCI fuel, causing ignition and heat release timings to be advanced and the peak of heat release rate to be increased at different engine speeds and steady operating conditions. Moreover, with the increase of engine speed, the influence of mixed additives on HCCI combustion is more obvious. In addition, mixed additives are beneficial to improving HCCI engine misfire at the high speed, and make the engine operating stable at specified speeds.