engine room  
noun [ C ] uk/ˈen.dʒɪn ˌruːm/ us/ˈen.dʒɪn ˌruːm/
  (ROOM)     
  发动机房;轮机舱
the place on a ship where the engine is
   (FOOTBALL PLAYER)      
 (足球)中场(球员)
in football, a midfield player or group of midfield players that have a lot of energy and strongly influence the level of activity within the team
  Pearce has been the engine room of the team this season. 这个赛季皮尔斯一直是该队的中场发动机。