Hydrogen aspiration in a direct injection type diesel engine-its effects on smoke and other engine performance parameters

Abstract

An experimental study was undertaken to investigate the possibility of reducing diesel particulates in the exhaust by aspirating small quantities of gaseous hydrogen in the intake of a diesel engine. A single cylinder, direct injection type diesel engine was used in the experiments. Hydrogen flow rates equivalent to about 10% of the total energy substantially reduced smoke emissions at part loads. At the full rated load, reduction in smoke levels was limited; this is believed to be due to the lower amounts of excess air available in the cylinder. It was found that the engine thermal efficiency was dependent on the portion of hydrogen energy, out of the total input energy, supplied to the engine. There was no significant change in the hydrocarbon emissions but oxides of nitrogen in the exhaust increased with an increase in hydrogen energy.