Investigation of Flame Propagation and Pollutants Formation Within a Combustion Chamber of an RCCI Engine

The environmental problems caused by global warming have led to strict regulations to limit greenhouse gas production. These laws have accelerated the changes in the automotive and transportation industries. Reactivity controlled compression ignition (RCCI) combustion has always been considered one of the concepts that can increase the efficiency of internal combustion engines by more than 50%. In this research, by using three-dimensional simulations, we investigate the basis and theory of RCCI combustion. Investigations have shown that flame propagation in RCCI combustion is different from conventional combustions, so that the onset of a flame kernel and the start of energy release are similar to diesel combustion, but the flame propagation is quite different. In the RCCI engine, the whole combustion chamber is ignited so fast by forming several new flame kernels. The maximum combustion chamber temperature is reduced by about 12% in RCCI combustion. In the following, the formations of NOx and soot are investigated, and the process of pollutant formation reactions is accurately analyzed. The RCCI combustion could achieve a near-zero NOx and near-zero soot emission.