Abstract: An internal combustion engine includes an engine body provided with a cylinder having openings for intake and exhaust, and valve bodies that open and close the openings, cam shafts provided with cam lobes that depress the valve bodies so as to open the openings, and bearing members that pivotally supports the cam shaft via lubricating oil. Each cam shaft includes cam journals pivotally supported by the bearing members, and a hollow bore extending in the axial direction of the cam shaft. When an area of the cam journal around the hollow bore is seen in a cross-sectional view perpendicular to the axial direction, a thickness on a projecting side of the cam lobe is X1, and a thickness on the opposite side to the cam lobe in the circumferential direction is X2, a relationship of X1>X2 is satisfied in at least a part of the cam journal.

Abstract: An internal combustion engine is provided, which includes an engine body provided with a cylinder having openings for intake and exhaust, and valve bodies that open and close the openings, cam shafts, each provided with a cam lobe that depress the corresponding valve body to open the openings, and bearing members pivotally supporting the cam shaft via lubricating oil. The cam shaft includes cam journals pivotally supported by the bearing members, and a recess formed at a position of the cam journal, opposing the cam lobe in the circumferential direction, and depressed radially inwardly of the cam journal, the recess being deeper in an axial end part of the cam journal than an axial center part.

Abstract: An internal combustion engine is provided, which includes an engine body provided with a cylinder and a piston reciprocatably accommodated in the cylinder, a crankshaft that converts reciprocating movement of the piston into rotational movement, and a bearing member pivotally supporting the crankshaft via lubricating oil. The crankshaft includes a crank journal pivotally supported by the bearing member, and a counterweight extending radially outward from an axial end part of the crank journal. The crank journal has a recess formed in a part thereof corresponding to the extended position of the counterweight, the recess being depressed radially inwardly. The recess is deeper at the axial end part of the crank journal than an axial center part.

Abstract: An internal combustion engine is provided, which includes an engine body provided with a cylinder and a piston reciprocatably accommodated in the cylinder, a crankshaft that converts reciprocating movement of the piston into rotational movement, and a bearing member pivotally supporting the crankshaft via lubricating oil. The crankshaft includes a crank journal pivotally supported by the bearing member, and a counterweight extending radially outward from an axial end part of the crank journal. The crank journal has a recess formed in a part thereof corresponding to the extended position of the counterweight, the recess being depressed radially inwardly. The recess is deeper at the axial end part of the crank journal than an axial center part.

Abstract: An internal combustion engine is provided, which includes an engine body provided with a cylinder having openings for intake and exhaust, and valve bodies that open and close the openings, cam shafts, each provided with a cam lobe that depress the corresponding valve body to open the openings, and bearing members pivotally supporting the cam shaft via lubricating oil. The cam shaft includes cam journals pivotally supported by the bearing members, and a recess formed at a position of the cam journal, opposing the cam lobe in the circumferential direction, and depressed radially inwardly of the cam journal, the recess being deeper in an axial end part of the cam journal than an axial center part.

Abstract: An internal combustion engine includes an engine body provided with a cylinder having openings for intake and exhaust, and valve bodies that open and close the openings, cam shafts provided with cam lobes that depress the valve bodies so as to open the openings, and bearing members that pivotally supports the cam shaft via lubricating oil. Each cam shaft includes cam journals pivotally supported by the bearing members, and a hollow bore extending in the axial direction of the cam shaft. When an area of the cam journal around the hollow bore is seen in a cross-sectional view perpendicular to the axial direction, a thickness on a projecting side of the cam lobe is X1, and a thickness on the opposite side to the cam lobe in the circumferential direction is X2, a relationship of X1>X2 is satisfied in at least a part of the cam journal.

Abstract: A cylinder block includes a body part where a cylinder is formed, an outer wall part made of fiber reinforced resin and surrounding an outer circumference of the body part, and a metal member attached to the outer wall part. The outer wall part is comprised of an inner layer surrounding the outer circumference of the body part, and an outer layer surrounding an outer circumference of the inner layer. A density of reinforcing fiber contained in the outer layer is higher than a density of reinforcing fiber contained in the inner layer. The metal member is attached to the outer wall part so as to contact the outer layer. The reinforcing fiber contained in the outer layer has an electric insulating property.

Abstract: A cylinder block includes a body part where a cylinder is formed, an outer wall part made of fiber reinforced resin and surrounding an outer circumference of the body part, and a metal member attached to the outer wall part. The outer wall part is comprised of an inner layer surrounding the outer circumference of the body part, and an outer layer surrounding an outer circumference of the inner layer. A density of reinforcing fiber contained in the outer layer is higher than a density of reinforcing fiber contained in the inner layer. The metal member is attached to the outer wall part so as to contact the outer layer. The reinforcing fiber contained in the outer layer has an electric insulating property.

Abstract: A cylinder block includes a metal body part having a cylinder, and an outer wall part made of fiber reinforced resin, surrounding an outer circumference of the body part. A part of the outer wall part at BDC side in a cylinder axis direction contacts a bottom wall forming part. The outer wall part is comprised of an inner layer surrounding the outer circumference of the body part, and an outer layer surrounding an outer circumference of the inner layer. A density of reinforcing fiber contained in the outer layer is higher than that in the inner layer. A thickness of a part of the inner layer at BDC side in the cylinder axis direction is greater than that of the TDC-side inner layer. A thickness of a part of the outer layer at TDC side in the cylinder axis direction is greater than that of the BDC-side outer layer.

Abstract: There is provided, in one aspect of the present description, an engine. In one example, the engine comprises a cylinder block, a cylinder head, a sheet metal gasket interposed between the block and the head, a first projection projecting outwardly and laterally from a side portion of the block, and a second projection projecting outwardly and laterally from a side portion of the head, the first projection and the second projection facing each other along a coupling surface between the block and the head. The engine further comprises an extension extending from a main body of the sheet metal gasket and located between the first projection and the second projection, and a resilient portion which is provided in the extension, formed resiliently in a direction perpendicular to the coupling surface, and compressed between the first projection and the second projection when the head is fastened on the block.

Abstract: There is provided, in one aspect of the present description, an engine. In one example, the engine comprises a cylinder block, a cylinder head, a sheet metal gasket interposed between the block and the head, a first projection projecting outwardly and laterally from a side portion of the block, and a second projection projecting outwardly and laterally from a side portion of the head, the first projection and the second projection facing each other along a coupling surface between the block and the head. The engine further comprises an extension extending from a main body of the sheet metal gasket and located between the first projection and the second projection, and a resilient portion which is provided in the extension, formed resiliently in a direction perpendicular to the coupling surface, and compressed between the first projection and the second projection when the head is fastened on the block.