The Performance of an IDI Diesel Engine Having Low Concentrations of Hydrogen in the Intake Air

Dual-fuel engines represent a simple and flexible approach to employing gaseous fuels including hydrogen in conventional diesel engines. This paper reports on the investigation into the effects on performance, emissions and combustion characteristics of introducing low volumetric concentrations of hydrogen into the intake air of a multi-cylinder IDI diesel engine. It is shown that increasing the admission of hydrogen up to a certain low concentration increased power output, whereas further increases in hydrogen admission began to decrease power output. For the same total fuel energy input, the engine brake power and thermal efficiency were less with hydrogen admission as compared to the corresponding pure diesel operation. The exhaust gas opacity and the emissions of oxides of nitrogen and carbon monoxide showed correspondingly relatively significant reductions.