Effects of passive pre-chamber jet ignition on knock combustion at hydrogen engine

The use of gaseous fuels, including hydrogen, to fuel an engine enables an increase in efficiency and a significant reduction in toxic exhaust emissions. The research reported in this paper concerns a two-stage passive hydrogen combustion system for analyzing knock combustion under varying process conditions. The research was conducted using a single-cylinder AVL 5804 engine to determine the effect of the center of combustion (CoC) and excess air ratio (λ) on engine knock conditions and other engine parameters. The tests were carried out at a constant speed of n = 1500 rpm, variable CoC adjustments (2–18°CA aTDC), and a variable value of λ = 1.25–2.0. It was determined that at λ = 1.25–1.5, knocking combustion is quite intense, and further increases in λ this knocking are needed. The excess air ratio λ was found to have a much greater effect on the knock appearance in the engine than the center of combustion position.