The　hydrogen　supply　of　the　fuel　cell　system　is　realized　by　the　cooperation　of　multiple　components.　Transient　characteristics　of　a　single　component　can　affect　the　performance　of　other　components.　In　this　study,　a　three-dimensional　multi-component　computational　fluid　dynamics　(CFD)　model　was　developed　to　investigate　the　synergistic　transient　characteristics　of　the　hydrogen　recirculation　components　such　as　hydrogen　injector,　ejector,　and　purge　valve　in　an　80　kW　PEMFC.　The　results　show　that　the　entrainment　performance　of　the　ejector　is　reduced　under　unsteady　purge　conditions　compared　with　steady　conditions.　The　pressure　fluctuation　of　the　secondary　flow　is　significant　even　under　purge　closed　durations.　There　are　drastic　changes　in　velocity　and　pressure　in　the　ejector,　especially　in　the　mixing　chamber.　Moreover,　an　abundant　hydrogen　supply　capacity　of　the　injector　is　necessary　to　deal　with　the　excessive　anode　pressure　fluctuation.　The　feedforward-feedback　integrated　control　of　the　injector　is　a　more　efficient　strategy　to　reduce　pressure　fluctuations　compared　with　the　feedback　control.　©　2022　Hydrogen　Energy　Publications　LLC