Investigation of hydrogen addition on the combustion, performance, and emission characteristics of a heavy-duty engine fueled with diesel/natural gas

Abstract

In this work, a three-dimensional computational fluid dynamics model of a diesel engine cylinder was developed, and a chemical reaction mechanism containing 53 species and 325 reactions was established by the CHEMKIN program. The purpose of this work is to investigate the effect of hydrogen (H2) addition on the performance, combustion and emission characteristics of a dual-fuel engine in term of in-cylinder pressure, in-cylinder temperature, brake power, brake thermal efficiency, brake specific fuel consumption, NOx emission, CO emission and soot emission. Then, the model was validated by the experimental results at different loads and used for analysis. The results showed that adding 15% H2 at 100% load resulted in a 4.6% reduction in BSFC and a 10.3% increase in brake power compared to diesel/natural gas dual-fuel. In addition, the performance improvement was more pronounced with the addition of H2 at higher engine load. H2 can increase the flame spread, shorten the combustion duration, and significantly increase peak cylinder pressure and temperature. However, adding H2 to dual-fuel engine at the cost of a slight increase in NOx is a promising solution to its higher unburned gas emissions at low loads.