Abstract
Nitrogen oxide (NOx) and particulate matter (PM) emissions of diesel vehicles are regarded as a source of air pollution, and there is a global trend to enforce more stringent regulations on these exhaust gas constituents in the early years of the 21st century. On the other hand, the excellent thermal efficiency of diesel engines is certainly a welcome attribute from the standpoints of conserving energy and curbing global warming. Recently, many research institutes around the world have been using high-efficiency direct-injection (DI) diesel engines to research emission control technologies. The authors have also been researching emission control technologies using a high-efficiency DI diesel engine. As a result of this work, we have developed a new combustion concept, called Modulated Kinetics (MK), that reduces NOx and smoke simultaneously through low-temperature combustion and premixed combustion, respectively (1), (2) .
This paper describes the combustion and emission characteristics obtained when this new combustion concept was applied to a single-cylinder engine and a multi-cylinder engine. It also shows the possibility of obtaining high-efficiency, ultra-clean internal combustion engines for the 21st century.