Turbulent　jet　ignition　(TJI)　is　an　advanced　ignition　strategy　that　can　improve　the　ignition　and　combustion　characteristics　of　low-reactivity　mixtures.　The　utilization　of　TJI　system　may　be　reliable　to　achieve　the　application　of　ammonia　(NH3)　internal　combustion　engines.　Hydrogen　(H2)　is　a　potential　auxiliary　fuel　for　the　pre-chamber,　and　the　injection　of　a　small　amount　of　H2　in　the　pre-chamber　is　beneficial　for　promoting　the　ignition　and　combustion　of　NH3/air　in　the　main　chamber.　In　this　study,　the　ignition　and　combustion　characteristics　of　NH3/air　adopting　the　active　TJI　with　assisted　H2　injection　in　pre-chamber　were　investigated,　and　the　relevant　experiments　were　conducted　in　the　constant　volume　combustion　bomb　system.　The　results　show　that　the　H2　pre-chamber　can　improve　the　flammability　of　NH3/air,　and　properly　increasing　H2　injection　is　conducive　to　the　rapid　ignition　of　NH3/air　in　the　main　chamber.　The　turbulence　introduced　into　the　main　chamber　by　the　hot　jet　enhances　the　combustion　process,　and　the　generation　of　turbulence　weakens　the　sensitivity　of　the　combustion　rate　to　the　reactivity　of　the　unburned　mixture.　The　turbulence　intensity　can　be　increased　by　decreasing　the　pre-chamber　orifice　diameter,　which　increases　the　ignition　delay　but　significantly　shortens　the　combustion　duration.　©　2024　Elsevier　Ltd