The Influence of Injection Strategy on the Ignition Characteristics of Diesel/Ammonia Premixture

In this paper, based on the optical experimental platform of constant combustion and rapid compression expansion machines, the effects of spray characteristics and injection strategies of diesel in an atmosphere with ammonia on the ignition characteristics of a diesel/ammonia premixture are studied. It is found that in the spray development stage, the liquid-phase penetration distance in ammonia is greater than that in nitrogen. However, the results are opposite in the equilibrium stage. Appropriately increasing the diesel injection pressure can shorten the ignition delay and increase the peak cylinder pressure and projected flame area. The closer the injection time is to TDC, the shorter the ignition delay, and the peak cylinder pressure and heat release rate are lower. The pre-injection strategy can effectively shorten the ignition delay and improve the cylinder pressure and heat release rate.