In　the　present　paper,　the　cyclic　variations　of　a　hydrogen-blended　gasoline　rotary　engine　operated　under　various　conditions　were　experimentally　investigated.　The　experiments　were　carried　out　on　a　modified　hydrogen-gasoline　dual-fuel　rotary　engine　equipped　with　an　electronically-controlled　fuel　injection　system.　An　electronic　control　module　was　specially　made　to　command　the　fuel　injection,　excess　air　ratio　and　hydrogen　volumetric　fraction.　The　tested　engine　was　first　run　at　idle　condition　with　a　speed　of　2400　rpm　and　then　operated　at　4500　rpm　to　investigate　the　cyclic　variations　of　a　hydrogen-enriched　gasoline　rotary　engine　under　different　hydrogen　volumetric　percentages　in　the　total　intake,　excess　air　ratios　and　spark　timings.　The　experimental　results　demonstrated　that　the　coefficient　of　variations　(in　peak　pressure,　engine　speed,　flame　development　period　and　flame　propagation　period)　of　the　gasoline　rotary　engine　were　distinctly　decreased　with　the　increase　of　hydrogen　volume　fraction　under　all　the　tested　conditions.　In　particular,　at　idle　and　stoichiometric　conditions,　the　coefficient　of　variation　in　CAO-10　and　CA10-90　were　reduced　from　9.25%　to　5.01%,　15.40%　to　8.70%,　respectively.　(C)　2017　Hydrogen　Energy　Publications　LLC.　Published　by　Elsevier　Ltd.　All　rights　reserved.