Syngas　is　a　fuel　with　a　huge　market　and　low　carbon　emission,　which　has　been　proven　to　be　well　applied　to　internal　combustion　engines.　WRE　with　high　power　density　can　effectively　improve　the　power　characteristic　when　syngas　is　employed　as　fuel　in　engines,　however,　which　has　not　been　reported　publicly.　This　work　aims　to　provide　insights　into　the　performance　of　syngas-fueled　WRE　under　different　CO/H2　ratios　and　thus　gives　theoretical　guidance　for　its　application.　The　test　is　done　at　1500　r/min　and　part　load.　It　is　found　that　with　the　increase　of　the　volumetric　ratio　of　CO　in　syngas　(CO%),　the　efficiency,　torque　and　carbon　emissions　are　deteriorated,　however,　the　NO　emission　is　significantly　improved　and　the　knock　level　is　also　reduced.　In　addition,　on　the　premise　of　constant　CO%,　a　high　brake　thermal　efficiency,　low　NO　emission　and　knock　intensity　can　be　achieved　at　lean　combustion.　In　particular,　when　CO%　is　10%,　the　combustion　efficiency　of　CO　is　independent　of　the　excess　air　ratio,　while　when　CO%　is　20%,　that　is　decreased　with　increasing　excess　air　ratio.　In　summary,　the　syngas-fueled　WRE　is　recommended　to　adopt　the　qualitative　control　and　the　syngas　with　low　CO%.(c)　2023　Hydrogen　Energy　Publications　LLC.　Published　by　Elsevier　Ltd.　All　rights　reserved.