Stability of autoignition and combustion in low-heat-rejection, ceramic methanol ATAC engine (Analysis of cyclic variation at high wall temperature and lean burn)

ATAC (Active Thermo-Atmosphere Combustion) is stable in the lean limit, because it is `bulk-like' and/or `nonpropagating' combustion caused by self-ignition. In a low-heat-rejection methanol-fueled engine, we investigated the influence of ATAC operation with weakening premixed gas and raising temperature of the combustion chamber wall on cyclic variation of ignition and combustion. We analyzed the cyclic variation of autoignition timing, combustion duration, combustion quantity and instantaneous heat flux on the wall of the combustion chamber, from which we clarified the correlation between autoignition timing and combustion duration, autoignition timing and combustion quantity, and combustion duration and combustion quantity.