Internal combustion engine having at least one cylinder, preferably a large vessel engine with at least one cylinder having an inner diameter of at least 200mm, preferably a low pressure fuel gas engine, a dual-fuel or multi-fuel engine, having at least one piston which is movably arranged within the cylinder, having a rotatably arranged crankshaft, with the piston being connected to a crosshead via a piston rod, and with a crosshead pin connected to the piston rod, and with the crosshead being connected to the crankshaft via a connecting rod to drive the crankshaft, the engine comprising a variable compression ratio device for changing a compression ratio of an engine, the variable compression ratio device being provided with a fluid chamber arranged in the inside of the crosshead pin, in which the piston rod is moveable relative to a bottom of the fluid chamber by a pressure-increased working fluid being supplied into the fluid chamber, the piston rod comprising cooling channels (14a, 14b), the crosshead pin comprising at least one first flow path for guiding a cooling fluid that is to be supplied to at least one of the cooling channels and at least one second flow path for guiding a cooling fluid that is to be discharged from at least one of the cooling channels, characterized in that, the first flow path is arranged in a first distance to a bottom plane defined by a bottom of the fluid chamber and the second flow path is arranged in a second distance to the bottom plane, the first distance being smaller than the second distance, such that the cooling fluid is suppliable to at least one of the cooling channels in an area between the plane defined by the bottom of the fluid chamber and the area where the cooling fluid is dischargeable from the at least one of the cooling channels, wherein the first flow path comprises a plurality of first channels, preferably uniformly, arranged in a first cross-section of the crosshead pin parallel to the bottom plane. having at least one piston which is movably arranged within the cylinder, having a rotatably arranged crankshaft, with the piston being connected to a crosshead via a piston rod, and with a crosshead pin connected to the piston rod, and with the crosshead being connected to the crankshaft via a connecting rod to drive the crankshaft, the engine comprising a variable compression ratio device for changing a compression ratio of an engine, the variable compression ratio device being provided with a fluid chamber arranged in the inside of the crosshead pin, in which the piston rod is moveable relative to a bottom of the fluid chamber by a pressure-increased working fluid being supplied into the fluid chamber, the piston rod comprising cooling channels (14a, 14b), the crosshead pin comprising at least one first flow path for guiding a cooling fluid that is to be supplied to at least one of the cooling channels and at least one second flow path for guiding a cooling fluid that is to be discharged from at least one of the cooling channels, characterized in that, the first flow path is arranged in a first distance to a bottom plane defined by a bottom of the fluid chamber and the second flow path is arranged in a second distance to the bottom plane, the first distance being smaller than the second distance, such that the cooling fluid is suppliable to at least one of the cooling channels in an area between the plane defined by the bottom of the fluid chamber and the area where the cooling fluid is dischargeable from the at least one of the cooling channels, wherein the first flow path comprises a plurality of first channels, preferably uniformly, arranged in a first cross-section of the crosshead pin parallel to the bottom plane.