Ignition and combustion characteristics of ammonia applying an ignition chamber fueled by methanol and gasoline

Ammonia holds the potential for wide application in internal combustion engines. The turbulent jet ignition system features strong ignition energy and excellent multi-point combustion advantages, which are beneficial for ammonia combustion. Gasoline and methanol are candidate fuels for ignition chamber due to the superior combustion performance. This study compares and analyzes performance of gasoline and methanol as ignition chamber fuels to investigate the effects on ammonia ignition and combustion characteristics during the cold and hot jet stages under varying equivalence ratios and energy percentage conditions. Additionally, a self-defined parameter of jet angle is proposed for investigating the ignition moment. It shows that energy percentage injected into the ignition chamber can affect the local equivalence ratio inside the ignition chamber under different fuel conditions. A higher energy percentage of ignition chamber benefits the ignition capability and combustion performance in the methanol ignition chamber mode, while negatively affects the gasoline ignition chamber mode. Moreover, the combustion performance with gasoline ignition chamber is more stable than that of methanol ignition chamber in response to the changes in equivalence ratio. The ignition chamber with a methanol energy percentage of 2.0 % at the ammonia equivalence ratio of 1.1 has excellent overall performance in the current study. The findings could provide theoretical foundations for the utilization of ammonia engines with an ignition chamber.