The Mechanism of Particle Formation in Non-Premixed Hydrogen Combustion in a Direct-Injection Internal Combustion Engine

There is a widely spread public and expert opinion that hydrogen combustion is a pathway for eliminating the formation of carbon-based pollutants, which produces near-zero-emissions. However, our studies show that non-premixed hydrogen combustion in engines may result in an enhanced particles formation, which is substantially higher than that stemming from hydrocarbon fuel combustion. This discovery contradicts all previously published data on particle formation in hydrogen combustion. We have accomplished an interlinked series of fundamental and engine studies enabling us to understand the physical reasons behind this apparent discrepancy and identify the mechanism governing particle formation in hydrogen combustion. The latter in non-premixed hydrogen burning is a result of a combined influence of the hydrogen low flame quenching distance, intensifying lubricant evaporation, and the gasdynamic interaction between the lubricant vapor and the fuel core-jet. This interaction results in the lubricant vapor entrainment into the chamber bulk with its subsequent combustion and particle formation.