Computational Investigation of Combustion, Performance, and Emissions of a Diesel-Hydrogen Dual-Fuel Engine

This paper aims to expose the effect of hydrogen on the combustion, performance, and emissions of a high-speed diesel engine. For this purpose, a three-dimensional dynamic simulation model was developed using a reasonable turbulence model, and a simplified reaction kinetic mechanism was chosen based on experimental data. The results show that in the hydrogen enrichment conditions, hydrogen causes complete combustion of diesel fuel and results in a 17.7% increase in work capacity. However, the increase in combustion temperature resulted in higher NOx emissions. In the hydrogen substitution condition, the combustion phases are significantly earlier with the increased hydrogen substitution ratio (HSR), which is not conducive to power output. However, when the HSR is 30%, the CO, soot, and THC reach near-zero emissions. The effect of the injection timing is also studied at an HSR of 90%. When delayed by 10°, IMEP improves by 3.4% compared with diesel mode and 2.4% compared with dual-fuel mode. The NOx is reduced by 53% compared with the original dual-fuel mode. This study provides theoretical guidance for the application of hydrogen in rail transportation.