Numerical Investigation on Performance Improvement of Hydrogen-diesel Fuelled Engine with Various Charge Induction Strategies

Abstract

In this work, effects of various H2 charge induction strategies on the performance and emissions of H2 - diesel dual fuel engine have been studied through numerical analysis using a high-fidelity computational fluid dynamics tool–Converge. A 120° three-dimensional (3D) sector model was created for the engine (port fuel injected H2 and direct injected diesel dual fuel) under study. Closed cycle simulations have been carried out to understand the in-cylinder combustion and emission formation processes. Results of the study showed that an addition of H2 at lower loads deterred the performance of the engine due to the lower combustion temperatures, but at higher loads H2 starts actively participating in combustion, thus improving the performance. It has been noticed that combustion efficiency of H2 fuel at lower loads is poor due to lower in-cylinder temperature and charge dilution effect. Other than this, at lower H2 substitution levels, lean H2 -air mixture outside the diesel spray plume zone caused poor combustion efficiency of H2 fuel. Because of replacement of carbon-based fuel with H2 , a reduction in carbon dioxide, carbon monoxide emissions have been observed with increased HES. While at higher loads, the combustion performance is found better than that of the lower loads due to the increased temperature leading to improved combustion participation of hydrogen. The NOx emissions were found to be high at higher loads with high HES.