Patent ID: 7216612
Filing Date: 2007-05-15
Classification: F02B,F02F

Abstract:
1. An internal combustion engine comprising: a cylinder head; a cylinder having an opposed surface including an opening and opposed to the cylinder head; a cylinder inner surface extending from a peripheral edge of the opening in a predetermined cylinder axial direction to define a combustion chamber; a water jacket arranged around the opening on the opposed surface substantially in the cylinder axial direction and including a bottom wall defining a concave bottom; and a piston provided in the cylinder, the piston including a piston body and a plurality of rings mounted to a periphery of the piston body to be aligned in the cylinder axial direction; wherein the plurality of rings include a bottom ring positioned on a side farthest from the cylinder head and having an upper end that constitutes an end toward the cylinder head and a lower end that constitutes an end in opposition to the cylinder head; at least a portion in the cylinder between the cylinder inner surface and the water jacket is made of a material having a higher thermal conductivity than that of iron; and the bottom wall of the water jacket is positioned in the cylinder axial direction between the opposed surface and the lower end of the bottom ring when the piston is disposed in a top dead center position.