Abstract
This study demonstrates the cold start performance of an ammonia mono-fueled engine system. The system was composed with a commercial four-cylinder spark ignition engine and a developed on-board ammonia reformer by means of autothermal reforming. A TWC (three-way catalyst) and a SCR (Selective Catalytic Reduction) catalyst were also adapted the system for exhaust aftertreatment. The ATR reformer provided stable hydrogen within several seconds with supplying electrically preheated ammonia-air mixture. The engine achieved a starting operation in 3 seconds after the starter turned on although the first combustion took place under relatively low hydrogen fraction. Zero ammonia emissions and pretty low NOx and N2O emissions were obtained during cold start following idling condition by controlling the mixture excess air ratio depending on each aftertreatment catalyst conditions. The adsorbed ammonia on the SCR passing through the TWC before its activation was oxidated by SCR reaction under lean operation.
