Effect of the HPDI and PPCI Combustion Modes of Direct-Injection Natural Gas Engine on Combustion and Emissions

Natural gas (NG) engines have very broad application prospects. The pilot-ignited NG diesel engine can be organized into two combustion modes according to the sequence of oil and injection: (1) High-pressure direct injection, where is mainly diffused combustion; (2) partially premixed compression ignition, combustion. In this study, we used CONVERGE explore influence injection timing on distribution mixture equivalence ratio, ignition characteristics, thermal efficiency, emission, reaction rate under modes. We also a multi-step soot model analyze particle mass quantity. showed herein that significantly affects in cylinder, thereby consequently affecting process. Both early late times were not conducive addition, mass, quantity, diameter produced by diffusion larger than those with