Characteristics of multiple injections

A look at the effects that pilot-injection fuel quantity and timing have on light-duty engine emissions.

Research continues into new technologies (such as premixed combustion) that involve fundamental improvement in combustion modes. A lot of attention is naturally paid to fuel injection, the dominant factor for diesel engines that operate by burning sprayed fuel. The use of a pilot injection, in particular, has proven beneficial in reducing emissions.

NOx reduction and less noisy combustion are advantages gained from pilot injection because it shortens the ignition delay period of main injection and limits the amount of initial premixed combustion. Many studies have reported the effects of pilot-injection combustion on main combustion, but there still remains many unexplained areas concerning the phenomenon involved; few analyses have been conducted on combustion of the pilot-injected fuel itself.