Patent ID: 8291871

Claim:
Device for adjusting the compression ratio of a variable compression ratio engine comprising a hydraulic double-acting control actuator ( 8 ) comprising an upper chamber ( 121 ) and a lower chamber ( 122 ) and at least one actuator piston ( 13 ) connected to a control rack ( 7 ), characterized in that it comprises: at least two balls ( 401 , 402 ) or valve elements each resting on a seat ( 403 , 404 ) and closing off respectively one and the other end of a transfer channel ( 405 ) connecting the upper chamber ( 121 ) and the lower chamber ( 122 ) of the control actuator ( 8 ), said balls ( 401 , 402 ) acting as a nonreturn valve element when they are held on their seat ( 403 , 404 ) by a spring ( 408 , 409 ) in order to allow the hydraulic fluid to pass in only one direction; and lifting means ( 410 ) making it possible to raise the balls ( 401 , 402 ) from their seat ( 403 , 404 ) so that said balls allow the hydraulic fluid to pass in both directions.