Abstract: A valve operating system for a multicylinder engine opens and closes a pair of valves provided on each of cylinders by means of a pair of rocker arms operated by a cam provided on a camshaft supported on a cam holder. When viewed in a direction of a cylinder axis, the pair of rocker arms of at least one of the cylinders are inclined in opposite directions to each other with respect to a direction orthogonal to a camshaft axis. Therefore, thrust loads acting on the camshaft from the pair of rocker arms are counteracted individually for each of the cylinders, thereby enabling the thrust load to be reduced and axial movement of the camshaft to be prevented.

Abstract: A valve operating system for a multicylinder engine opens and closes a pair of valves provided on each of cylinders by means of a pair of rocker arms operated by a cam provided on a camshaft supported on a cam holder. When viewed in a direction of a cylinder axis, the pair of rocker aims of at least one of the cylinders are inclined in opposite directions to each other with respect to a direction orthogonal to a camshaft axis. Therefore, thrust loads acting on the camshaft from the pair of rocker al is are counteracted individually for each of the cylinders, thereby enabling the thrust load to be reduced and axial movement of the camshaft to be prevented.

Abstract: A cylinder head includes a combustion chamber recess on a lower surface, an exhaust port with downstream and upstream side channels, and downstream and upstream liners respectively inserted into the downstream and upstream side channels. The downstream side channel has an open end at a side surface of the cylinder head and an opposite end sealed by a bottom wall. The upstream side channel has an end open to the combustion chamber recess and an opposite end connected to a side portion of the downstream side channel. The downstream side liner includes a generally tubular member with a linear axis and has an insertion end abutting the bottom wall. The downstream side liner has a connecting hole in a side portion facing the upstream side channel and engaged by the upstream side liner, which also includes a generally tubular member.

Abstract: A timing transmission mechanism (T2) in an engine is formed of a chain transmission system (C) that is formed from a drive sprocket (20) mounted on a crankshaft (4), a driven sprocket (25) mounted on a pump input shaft (24) of a high pressure fuel pump (P), and a chain (22) wound around the drive sprocket (20) and the driven sprocket (25); and a gear transmission system (G) that is formed from a drive gear (26) mounted on the pump input shaft (24) coaxially with the driven sprocket (25) and a driven gear (27) mounted on a camshaft (13b) and meshing with the drive gear (26). This enables a timing transmission mechanism to be provided that can increase the degree of freedom in layout of the high pressure fuel pump without causing any increase in the number of components, the weight, or the backlash.

Abstract: A timing transmission mechanism (T2) in an engine is formed of a chain transmission system (C) that is formed from a drive sprocket (20) mounted on a crankshaft (4), a driven sprocket (25) mounted on a pump input shaft (24) of a high pressure fuel pump (P), and a chain (22) wound around the drive sprocket (20) and the driven sprocket (25); and a gear transmission system (G) that is formed from a drive gear (26) mounted on the pump input shaft (24) coaxially with the driven sprocket (25) and a driven gear (27) mounted on a camshaft (13b) and meshing with the drive gear (26). This enables a timing transmission mechanism to be provided that can increase the degree of freedom in layout of the high pressure fuel pump without causing any increase in the number of components, the weight, or the backlash.

Abstract: There is provided a support device for a rocker arm, which is capable of suppressing deformation or wear of a washer, and greatly improving the working efficiency in assembling the washer to the rocker arm. The support device supports the rocker arm having a supported portion, for driving an engine valve of an internal combustion engine. A rocker shaft is supported between a pair of shaft holders arranged in the cylinder head, for pivotally supporting the rocker arm thereon via the supported portion. A washer has engaging pieces, and is attached to one of opposed ends of the supported portion of the rocker arm and one of the shaft holders, in a manner interposed between the opposed ends. The one of the opposed ends is formed with an annular engaging portion for having the washer engaged thereon via the engaging piece.

Abstract: A valve train for an internal combustion engine includes a rocker shaft (9) provided with an oil passage, first and second rocker arms (7, 8) having support parts (7a, 8a) provided with bores (7b, 8b) to receive the rocker shaft (9) therein so as to be supported on the rocker shaft (9) for rocking motion, and a rocker arm interlocking mechanism (10) for selectively engaging or disengaging the first and the second rocker arms (7, 8). The first rocker arm (7) is provided with a pressure chamber (33) holding a piston (30) therein, a straight connecting passage 34 connected to the pressure chamber (33) and an oil passage (35)formed in the rocker shaft (9). An open end surface (7b1) of the bore (7b) of a first support wall (7e) of the rocker arm (7) is on an axially outer side of the pressure chamber (33).

Abstract: There is provided a support device for a rocker arm, which is capable of suppressing deformation or wear of a washer, and greatly improving the working efficiency in assembling the washer to the rocker arm. The support device supports the rocker arm having a supported portion, for driving an engine valve of an internal combustion engine. A rocker shaft is supported between a pair of shaft holders arranged in the cylinder head, for pivotally supporting the rocker arm thereon via the supported portion. A washer has engaging pieces, and is attached to one of opposed ends of the supported portion of the rocker arm and one of the shaft holders, in a manner interposed between the opposed ends. The one of the opposed ends is formed with an annular engaging portion for having the washer engaged thereon via the engaging piece.

Abstract: The present invention provides a valve operating system for internal combustion engines, having a roller rolling contacting a valve operating cam, the system being provided with an oil supply passage capable of reducing a pressure loss to a low level even when a flow rate of lubricating oil entering the oil supply passage increases in accordance with a heightened engine speed, improving the lubricating ability with respect to the roller, and attaining a long lifetime of a rocker arm.

Abstract: A valve train for an internal combustion engine includes a rocker shaft (9) provided with an oil passage, first and second rocker arms (7, 8) having support parts (7a, 8a) provided with bores (7b, 8b) to receive the rocker shaft (9) therein so as to be supported on the rocker shaft (9) for rocking motion, and a rocker arm interlocking mechanism (10) for selectively engaging or disengaging the first and the second rocker arms (7, 8). The first rocker arm (7) is provided with a pressure chamber (33) holding a piston (30) therein, a straight connecting passage 34 connected to the pressure chamber (33) and an oil passage (35)formed in the rocker shaft (9). An open end surface (7b1) of the bore (7b) of a first support wall (7e) of the rocker arm (7) is on an axially outer side of the pressure chamber (33).

Abstract: The present invention provides a valve operating system for internal combustion engines, having a roller rolling contacting a valve operating cam, the system being provided with an oil supply passage capable of reducing a pressure loss to a low level even when a flow rate of lubricating oil entering the oil supply passage increases in accordance with a heightened engine speed, improving the lubricating ability with respect to the roller, and attaining a long lifetime of a rocker arm.

Abstract: In a valve operating system for an internal combustion engine, wherein connected and disconnected states of cam followers can be switched over from one to another to change the valve operating characteristic of an engine valve, each cam follower includes a cam follower body having a pair of support walls integrally provided thereon and arranged in parallel to sandwich a roller therebetween, and a hollow roller shaft which is fitted and supported at outer peripheries of its opposite ends in through-bores in the support walls, and which has the roller rotatably carried at its intermediate portion. A first groove is defined in an outer peripheral surface of the through-bore in one support wall to extend circumferentially of the through-bore, and a second groove is defined in an outer peripheral surface of the roller shaft at its one end corresponding to the first groove.