Liquid ammonia spray flame with pre-chamber turbulent jet ignition

Previous studies employed the high-reactivity fuels to ignite the ammonia via a dual fuel injection strategy for compression ignition (CI) engines. However, there are still bottleneck problems. Therefore, the objective of this letter is to demonstrate a promising alternative method to achieve pre-chamber turbulent jet flame inducing liquid ammonia spray flame (PC-LASF). The effect of mixture reactivity in PC and injection timing on the ignition and propagation of liquid ammonia spray flame is investigated in a constant-volume chamber. The results have proven the feasibility of PC-LASF method and a stable ammonia spray flame with a two-stage combustion phenomenon is successfully achieved. The increase of hydrogen amount in pre-chamber will enhance the jet intensity. Two ignition modes, including the high-temperature jet flame and thermal atmosphere, are performed by precisely controlling the ammonia injection timing or ignition timing.