Ammonia　(NH3)　is　a　potential　alternative　fuel　for　internal　combustion　engines　to　achieve　zero-carbon　emissions.　And　partial　fuel　dissociating　is　a　feasible　strategy　to　improve　the　reactivity　of　NH3,　the　hydrogen　(H2)　generated　by　dissociation　can　effectively　promote　the　combustion　of　NH3.　This　study　aims　to　experimentally　investigate　the　ignition　and　combustion　characteristics　of　partially　dissociated　NH3　ignited　by　passive　turbulent　jet　ignition.　The　effects　of　the　dissociation　ratio　and　equivalence　ratio　were　analyzed.　The　results　show　that　the　dissociation　of　NH3　improves　the　ignition　and　combustion　performance　of　NH3,　reflected　in　lower　ignition　delay　and　combustion　duration.　In　addition,　as　the　dissociation　ratio　increases,　the　ignition　mechanism　in　the　main　chamber　changes　from　jet　ignition　to　flame　ignition,　which　can　significantly　reduce　the　ignition　delay.　Lean　conditions　are　more　conducive　to　achieving　flame　ignition,　the　jet　ignition　mechanism　on　the　rich　side　leads　to　a　higher　ignition　delay　compared　to　lean　conditions　at　low　dissociation　ratios.　However,　the　lean　mixture　shows　a　higher　combustion　duration　due　to　its　low　reactivity.　The　inhibiting　effect　of　additional　nitrogen　(N2)　increases　with　the　dissociation　ratio,　but　the　ignition　mechanism　and　flame　propagation　in　the　main　chamber　are　not　significantly　affected.　©　2024　Elsevier　Ltd