Abstract: An engine includes a cylinder head including a first oil path and a second oil path. The cylinder head includes a valve gear including a first support and a second support that support a rocker shaft. The first support includes, on its outer surface, a first constriction located at an inlet of a connection-switching third oil path and connected to the first oil path, and a second constriction connected to the second oil path. The second support includes, on its outer surface, a third constriction connected to the first oil path, and a fourth constriction located at an inlet of a lubrication fourth oil path and connected to the second oil path.

Abstract: An internal combustion engine switches valve operation states, reduces or prevents wear of a cam and a rocker arm, and reduces the size of the cylinder head to ensure a sufficient valve lift amount. A valve spring retainer includes a cylindrical portion including a first through hole with an inner diameter decreases from the first end portion toward the second end portion, a cone-shaped portion including a second through hole with an inner diameter increases as it extends away from the second end portion of the cylindrical portion, and a flange portion extending radially outward from the cone-shaped portion. An outer diameter of the cylindrical portion is constant from the first end portion to the second end portion, and an outer diameter of the cone-shaped portion increases as it extends away from the second end portion.

Abstract: A valve gear includes a lost motion mechanism including a lost motion spring. A pillar is inserted into the lost motion spring, and a seat supports a lower end portion of the lost motion spring. A protrusion is provided on an opposite side of the seat from the lost motion spring. When viewed from an axial direction of the lost motion mechanism, the protrusion does not project out of the seat. By fitting the protrusion into the recess of the cylinder head, the seat, i.e., the lost motion mechanism is attached to the cylinder head.

Abstract: An internal combustion engine switches valve operation states, reduces or prevents wear of a cam and a rocker arm, and reduces the size of the cylinder head to ensure a sufficient valve lift amount. A valve spring retainer includes a cylindrical portion including a first through hole with an inner diameter decreases from the first end portion toward the second end portion, a cone-shaped portion including a second through hole with an inner diameter increases as it extends away from the second end portion of the cylindrical portion, and a flange portion extending radially outward from the cone-shaped portion. An outer diameter of the cylindrical portion is constant from the first end portion to the second end portion, and an outer diameter of the cone-shaped portion increases as it extends away from the second end portion.

Abstract: An internal combustion engine includes, as a lost motion spring that urges a rocker arm toward a cam, a compression coil spring supported on a cylinder head. A shaft is located on an inner side of the compression coil spring and extends along a winding axis of the compression coil spring. The internal combustion engine significantly reduces or prevents a decrease in the fuel efficiency and an increase in the size of the variable valve mechanism, while surging is unlikely to occur while running at a high speed, and it is possible to reduce the size or the weight of the rocker arm.

Abstract: A valve gear includes a lost motion mechanism including a lost motion spring. A pillar is inserted into the lost motion spring, and a seat supports a lower end portion of the lost motion spring. A protrusion is provided on an opposite side of the seat from the lost motion spring. When viewed from an axial direction of the lost motion mechanism, the protrusion does not project out of the seat. By fitting the protrusion into the recess of the cylinder head, the seat, i.e., the lost motion mechanism is attached to the cylinder head.

Abstract: An engine includes a cylinder head including a first oil path and a second oil path. The cylinder head includes a valve gear including a first support and a second support that support a rocker shaft. The first support includes, on its outer surface, a first constriction located at an inlet of a connection-switching third oil path and connected to the first oil path, and a second constriction connected to the second oil path. The second support includes, on its outer surface, a third constriction connected to the first oil path, and a fourth constriction located at an inlet of a lubrication fourth oil path and connected to the second oil path.

Abstract: An internal combustion engine includes, as a lost motion spring that urges a rocker arm toward a cam, a compression coil spring supported on a cylinder head. A shaft is located on an inner side of the compression coil spring and extends along a winding axis of the compression coil spring. The internal combustion engine significantly reduces or prevents a decrease in the fuel efficiency and an increase in the size of the variable valve mechanism, while surging is unlikely to occur while running at a high speed, and it is possible to reduce the size or the weight of the rocker arm.

Abstract: An internal combustion engine allows easy installment of a support that pivotally supports a rocker arm while preventing fretting wear due to rising of the support. The internal combustion engine includes the support, at least a portion of which is located in a hole of a cylinder head, a rocker arm that is pivotally supported on the support, and a ball plunger that secures the support inside the hole. The ball plunger includes a spring seat that contacts with the support, a ball that contacts with the cylinder head, and a spring interposed between the spring seat and the ball.

Abstract: An internal combustion engine allows easy installment of a support that pivotally supports a rocker arm while preventing fretting wear due to rising of the support. The internal combustion engine includes the support, at least a portion of which is located in a hole of a cylinder head, a rocker arm that is pivotally supported on the support, and a ball plunger that secures the support inside the hole. The ball plunger includes a spring seat that contacts with the support, a ball that contacts with the cylinder head, and a spring interposed between the spring seat and the ball.

Abstract: A valve gear for an engine includes a camshaft including a valve drive cam, a rocker arm, a synchronous cam that rotates in synchronism with the valve drive cam, and a switching mechanism that switches a drive mode of an intake valve or an exhaust valve in a period defined by the synchronous cam. The switching mechanism includes a switch and a driver. The switch switches the drive mode by moving elements which define a valve gear system from the valve drive cam to the rocker arm. The driver includes a cam follower that is pushed by the synchronous cam and drives the elements of the valve gear system in directions to switch the drive mode by a force received from the cam follower. A period when the synchronous cam pushes the cam follower is a period when the intake valve or the exhaust valve is kept closed.

Abstract: A valve mechanism for an engine includes a camshaft, a rocker arm, a synchronization cam that rotates in synchronism with a valve driving cam, and a switch assembly that switches the driving state of an intake valve or an exhaust valve when a cam follower is pressed by the synchronization cam. The synchronization cam presses the cam follower at a time when the intake valve or the exhaust valve is closed. The switch assembly includes a switch unit that switches the driving state when a switch moves, a driver that drives the switch via a transmission, and a positioner including a spring-biased presser that engages with a concave portion of the transmission. The concave portion includes a first concave portion with which the presser engages in a first driving state, and a second concave portion with which the presser engages in a second driving state.

Abstract: A valve gear for an engine includes a camshaft including a cam, a rocker shaft, and a first rocker arm which swings when pressed by the cam. The valve gear includes a spring, which biases the first rocker arm and a second rocker arm which presses an intake valve or an exhaust valve, in a return direction. The valve gear includes a first pin hole of the first rocker arm, a second pin hole and a third pin hole of the second rocker arm, a first switch pin, a second switch pin, a third switch pin, and a switch which switches between a connected state and a non-connected state of the switch pins. The second rocker arm includes a stopper against which the first rocker arm abuts. When the first rocker arm abuts against the stopper, all of the pin holes are located on the same axis.

Abstract: A valve gear for an engine includes camshaft supports, a camshaft, a rocker housing separate from the cam shaft supports, a rocker shaft, a first rocker arm, and a second rocker arm selectively connected to the first rocker arm by switch pins. The valve gear includes a second switch pin and a hydraulic piston that presses the switch pins, and first and second hydraulic supplies that apply an oil pressure to the pistons. The second switch pin is provided in a second rocker arm, and the hydraulic piston is provided in the rocker housing. The first hydraulic supply includes a first oil passage in the second rocker arm, the rocker shaft, and the rocker housing. The second hydraulic supply includes a second oil hole in the rocker housing.

Abstract: A valve mechanism for an engine includes a camshaft, a rocker arm, a synchronization cam that rotates in synchronism with a valve driving cam, and a switch assembly that switches the driving state of an intake valve or an exhaust valve when a cam follower is pressed by the synchronization cam. The synchronization cam presses the cam follower at a time when the intake valve or the exhaust valve is closed. The switch assembly includes a switch unit that switches the driving state when a switch moves, a driver that drives the switch via a transmission, and a positioner including a spring-biased presser that engages with a concave portion of the transmission. The concave portion includes a first concave portion with which the presser engages in a first driving state, and a second concave portion with which the presser engages in a second driving state.

Abstract: A valve gear for an engine includes a camshaft including a cam, a rocker shaft, and a first rocker arm which swings when pressed by the cam. The valve gear includes a spring, which biases the first rocker arm and a second rocker arm which presses an intake valve or an exhaust valve, in a return direction. The valve gear includes a first pin hole of the first rocker arm, a second pin hole and a third pin hole of the second rocker arm, a first switch pin, a second switch pin, a third switch pin, and a switch which switches between a connected state and a non-connected state of the switch pins. The second rocker arm includes a stopper against which the first rocker arm abuts. When the first rocker arm abuts against the stopper, all of the pin holes are located on the same axis.

Abstract: A valve gear for an engine includes camshaft supports, a camshaft, a rocker housing separate from the cam shaft supports, a rocker shaft, a first rocker arm, and a second rocker arm selectively connected to the first rocker arm by switch pins. The valve gear includes a second switch pin and a hydraulic piston that presses the switch pins, and first and second hydraulic supplies that apply an oil pressure to the pistons. The second switch pin is provided in a second rocker arm, and the hydraulic piston is provided in the rocker housing. The first hydraulic supply includes a first oil passage in the second rocker arm, the rocker shaft, and the rocker housing. The second hydraulic supply includes a second oil hole in the rocker housing.

Abstract: A valve gear for an engine includes a camshaft including a valve drive cam, a rocker arm, a synchronous cam that rotates in synchronism with the valve drive cam, and a switching mechanism that switches a drive mode of an intake valve or an exhaust valve in a period defined by the synchronous cam. The switching mechanism includes a switch and a driver. The switch switches the drive mode by moving elements which define a valve gear system from the valve drive cam to the rocker arm. The driver includes a cam follower that is pushed by the synchronous cam and drives the elements of the valve gear system in directions to switch the drive mode by a force received from the cam follower. A period when the synchronous cam pushes the cam follower is a period when the intake valve or the exhaust valve is kept closed.

Abstract: A method and a selective-reduction catalyst system to remove foreign matter which may cause closure of a urea water path of a supply module and therearound. A urea water pressure is changed in the urea water path to remove the foreign matter.

Abstract: A method for producing a starting material for cutting capable of sufficiently eliminating residual stress is provided. The present invention is for producing a starting material for cutting which is a starting material for cutting to be cut/machined into a cut/machined product. The present invention includes a step for obtaining a primary molded article (1) by subjecting a molding material to primary forming, a step for subjecting the primary molded article (1) to a solution treatment and then quenching processing, and a step for subjecting the primary molded article (1) to secondary forming by cold forging after performing the quenching treatment, and obtaining a secondary molded article (2) as a starting material for cutting. The shape of the primary molded article (1) is determined in a manner as to eliminate the residual stress accumulating in the primary molded article (1) by the secondary forming.