Hydrogen-fuel　Wankel　rotary　engine　(HWRE)　has　higher　power　density　than　current　marketed　gasoline-fueled　engines,　however,　it　suffers　from　the　knock.　Hence,　the　purpose　of　this　work　is　to　investigate　the　impacts　of　cooled　exhaust　gas　recirculation　(EGR)　on　the　knock　in　a　HWRE　by　analyzing　the　relationship　between　some　knock-relevant　parameters　and　EGR　level,　which　is　conducted　at　1500　r/min,　wide-open　throttle,　stoichiometric　ratio,　and　respectively　constant　ignition　timing　and　CA50.　The　results　show　that　cooled　EGR　can　be　used　as　an　effective　means　of　eliminating　the　knock　in　HWRE.　As　the　EGR　level　is　increased,　the　size　and　distribution　of　knock-relevant　parameters,　such　as　knock　intensity,　knock　duration,　crank　angle　of　peak　knock　pressure　and　so　on,　show　their　own　change　characteristics.　Besides,　the　role　of　the　EGR　level　on　the　knock-relevant　parameters　is　also　influenced　by　the　ignition　timing　and　CA50.　Overall,　cooled　EGR　has　a　positive　effect　on　the　suppression　of　knock.　©　2022