Reacting Simulations of Multi-mode Combustion in a Rapid Compression Machine under HCCI and SICI Modes

Multi-mode combustion is of practical relevance due to the possibility of improving engine efficiency, emissions, and performance over single-mode combustion. In particular, Spark Induced Compression Ignition (SICI) can improve the load range and timing consistency of Homogeneous Charge Combustion Ignition (HCCI) while retaining HCCI’s advantage in low NOx emission and efficiency. We investigate multi-mode combustion dynamics by performing reacting simulations of HCCI and SICI modes in a Rapid Compression Machine (RCM) configuration of Strozzi et al. (2019). The compression phase is simulated using a dynamic mesh approach to resolve the flow field’s heterogeneity at Top-Dead-Center (TDC). The impact of this heterogeneity on combustion dynamics after TDC through hot-spot autoignition is investigated.