Study on Diesel Combustion in SIP-Innovative Combustion Technology

Abstract

Research activities on advanced combustion control for diesel passenger car engines are presented, which are part of SIP"innovative combustion technologies" supported by Council for Science, Technology and Innovation. The research aims at developing combustion technologies which enable 50% maximum thermal efficiency at high loads and CO₂ reduction at part loads. The major concept for higher thermal efficiency is simultaneous realization of higher degree of constant volume and lower cooling loss. For the middle- and low-load CO₂ reduction, wide-range PCCI combustion is pursued. Technologies are also investigated to mitigate the increase in combustion noise brought by the above-mentioned combustion concepts. As a result, the basic ideas and technologies were proposed for advanced combustion control, and the knowledges were accumulated for related phenomena; inverse-delta injection rate for eliminating rich mixtures in a spray flame, penetration and dispersion control of spray flame for reduced cooling loss, lean combustion for controling PCCI using ultrahigh injection pressure, and combustion noise reduction by combination of heat release rate control and shift of vibration frequency of engine parts. In addition, several numerical models have been developed for spray formation, oxidation of larger hydrocarbons, combustion noise and so on.