Numerical simulation of hydrogen-fueled light-duty direct injection SI engine with a hollow-cone jet injector

Document Type

Article

Publication Date

10-1-2026

Abstract

In the present study, the characteristics of a light-duty hydrogen engine operation is numerically investigated. A phenomenological barrel shock model coupled with a gaseous sphere injection model was applied to simulate peripheral gaseous injection from a hollow-cone injector. To simulate the combustion process in a spark ignition engine, the DPIK model and the G-equation model were employed. Modifying an existing hydrogen oxidation mechanism to improve predictive capability of end-gas combustion under engine-relevant elevated pressures and lean conditions, reaction kinetics were applied to 3-D CFD simulations of H2 jet combustion in a constant volume combustion chamber and an engine. With successful validation of the numerical models against CVCC measurements and experimental engine data, simulations were performed further to characterize the engine combustion with variation of such parameters as injection timing, ignition timing, and compression ratio. As injection timing changes, combustion phasing tends to change in a complex manner due to the coupled effects of the compositional and thermal stratification. Competing effects on flame speed by the change of gas temperature and pressure by compression/expansion, and the decrease of turbulence level are found to be the key factors that are governed by ignition timing variation. The timing of the burning of the richer end gases at elevated temperatures and pressures significantly affects combustion duration. For operation with increased compression ratios, knock-propensity can be mitigated by carefully optimized ignition timing at the small expense of thermal efficiency.

Publication Title

Applied Thermal Engineering

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