Increasing the power output of hydrogen internal combustion engines by means of supercharging and exhaust gas recirculation

Spark ignition engines can be relatively easily converted to hydrogen using port fuel injection (PFI). However, because of the lower volumetric energy density of a hydrogen–air mixture and the occurrence of abnormal combustion phenomena such as backfire, hydrogen-fueled PFI engines suffer from a power deficit in comparison with gasoline engines. This paper reports measurements on a single-cylinder hydrogen engine equipped with a supercharger and an exhaust gas recirculation (EGR) system. Using EGR combined with supercharging and a three-way catalyst (TWC) is shown to significantly increase the power output while limiting tailpipe emissions of oxides of nitrogen (NO_x).