Documentation of the performance and emissions of an ammonia fueled spark ignition engine.

Recent concern over this nation's dependence on foreign crude oil supplies has brought new emphasis on synthetic, non-petroleum fuels such as hydrogen, methanol, and anhydrous ammonia. This study was undertaken to document the performance and emissions of a spark ignition engine fueled with anhydrous ammonia. The engine used featured hemispherical combustion chambers and dual ignition. Gasoline fueled engine tests were also performed for comparison. Contrary to the findings of other amnonia studies, performance tests revealed no power drop-off at high speed (4000 rpm). Thermal efficiency at full throttle was above 30% but dropped significantly at part throttle. Also noted were an extreme resistance to knock and acceptable performance when burning very lean mixtures. Emissions of unburned ammonia were very high and would be unacceptable. Engine parameters such as cylinder head temperature, which have a significant effect on unburned fuel emissions, were not investigated, however, leaving this particular data somewhat inconclusive.