Patent ID: 7146940

Claim:
A combustion engine comprising at least one combustion chamber, which is delimited at one end by a head and delimited at a second end by a piston, the piston being arranged on a connecting rod by means of a piston pin, the piston including a first body portion that is fixed in relation to the piston pin and a second body portion with a delimiting surface that is movable in relation to the piston pin and facilitates a variable volume in said combustion chamber, a compression spring, which spring urges said movable surface with a spring force in the direction of the combustion chamber, a pressure chamber that can be supplied with hydraulic oil from a pressure source via a feed duct, which pressure chamber interacts with the movement of said moveable delimiting surface with the aim of being able to adjust the size of the combustion chamber depending on the combustion pressure, wherein said pressure chamber communicates with an inlet duct that always facilitates replenishment of hydraulic oil from said pressure source to said pressure chamber when the pressure in the pressure chamber falls below the pressure in the feed duct, and wherein said pressure chamber communicates with an outlet chamber, wherein said outlet chamber communicates with at least one outlet including a restricting device that continuously facilitates a flow of hydraulic oil out of the pressure chamber if the pressure in the chamber exceeds the pressure in said outlet chamber, and wherein a sleeve-shaped part is fixedly attached to one of said body portions, which sleeve-shaped part comprises a flange-shaped part, said pressure chamber and said outlet chamber being provided on a respective side of said flange-shaped part, and wherein said flange-shaped part is provided with at least one vertical duct that provides for communication between the pressure chamber and the outlet chamber, so that pressurized damping of the movement of said second body portion with said delimiting surface is obtained during operation.