The　application　of　hydrogen　direct-injection　enrichment　improves　the　performance　of　gasoline　Wankel　rotary　engine,　and　the　hydrogen　injection　strategy　has　a　significant　impact　on　combustion,　knock,　and　emissions.　The　Z160F　Wankel　rotary　engine　was　used　as　the　investigated　compact　engine,　and　the　simulation　model　was　developed　using　CONVERGE　software.　The　combustion,　knock　and　emissions　characteristics　of　the　engine　were　studied　with　the　different　mass　flow　of　hydrogen　injection,　i.e.,　the　trapezoid,　wedge,　slope,　triangle　and　rectangle　type　of　gas　injection　rate　shape.　In　the　numerical　simulations,　the　in-cylinder　pressure　oscillations　were　monitored　using　monitoring　points,　and　the　knock　index　(KI)　was　used　as　an　evaluation　indicator.　The　study　revealed　that　the　gas　injection　rate　shape　significantly　affected　the　mixture　of　hydrogen　and　air,　thus　impacting　combustion,　knock　and　emissions.　When　the　injection　rate　shape　was　rectangle,　the　flame　speed　was　faster,　the　peak　pressure　in　the　cylinder　was　higher,　and　the　corresponding　crank　angle　was　earlier,　which　led　to　higher　pressure　oscillations　in　the　cylinder　and　larger　KI.　Based　on　the　rectangle　injection　rate　shape,　the　KI　decreased　by　75.81%,　33.47%,　26.46%　and　76.58%　for　trapezoid,　wedge,　slope,　and　triangle,　respectively,　and　the　indicated　mean　effective　pressure　increased　by　15.68%,　5.07%,　0.56%　and　14.98%,　respectively.　Due　to　the　small　difference　in　maximum　temperature,　which　resulted　in　very　little　variation　in　nitrogen　oxides　for　each　injection　rate　shape,　the　total　hydrocarbon　emissions　of　the　trapezoid　and　triangle　injection　rate　shape　was　high　due　to　the　delayed　combustion　phase.　This　paper　provides　a　solution　for　direct　hydrogen　injection　to　improve　the　combustion,　knock　and　emissions　behavior　of　the　rotary　engine.　(c)　2021　Hydrogen　Energy　Publications　LLC.　Published　by　Elsevier　Ltd.　All　rights　reserved.