Abstract: In an internal combustion engine for a saddle riding vehicle, in which a gear transmission and a shift drum of a shift change device is stored in a crankcase, the gear transmission having a plurality of transmission shafts parallel to a crankshaft extending in a vehicle width direction, a single pump shaft common to first and second oil pumps is rotatably supported by the crankcase. First oil pump rotors of the first oil pump are disposed at a mating face of a pair of left and right crankcase half bodies. A second oil pump rotor of the second oil pump is disposed between a pump gear and the first oil pump and at a side surface, on a side opposite to the mating face, of one crankcase half body out of the pair of left and right crankcase half bodies, the pump gear being arranged in the pump shaft.

Abstract: A cam chain tensioner device of an internal combustion engine includes a cam chain tensioner, and a tensioner lifter pressing the cam chain tensioner to a cam chain. The tensioner lifter is mounted on an inclined upper surface of the cylinder head. The cylinder head has therein a valve train oil supply passage supplying oil from an oil pump to the valve train camshafts, and a tensioner lifter oil supply passage supplying oil to the tensioner lifter. The valve gear oil supply passage has a branching portion where the tensioner lifter oil supply passage branches. The branching portion is at a position higher than the tensioner lifter, and communicates with the tensioner lifter disposed at a position lower than the branching portion. It is thus possible to prevent fluttering of the cam chain and to reduce noise generated by the cam chain at the time of restart of the engine after it is stopped.

Abstract: In an oil filter attaching structure for a vehicle-mounted internal combustion engine, an oil filter of the engine is installed in a filter case integrally formed with a crankcase cover of a crankcase. The crankcase cover is mounted on a side surface of the crankcase so as to cover an end of a crankshaft supported by the crankcase to extend in vehicle widthwise directions. An internal combustion engine accessory and a transmission clutch device are disposed inside of the crankcase cover in respective positions forward and rearward of the crankshaft. The oil filter and an oil supply port are disposed inside of the crankcase cover in respective positions upward and downward of the crankshaft. The oil filter attaching structure efficiently utilizes the space for making itself smaller in size and for better maintainability.

Abstract: In a saddle-ride type vehicle in which a cylinder head of a single-cylinder engine main unit has a front wall and a rear wall, an exhaust system being connected to the front wall and an intake system being connected to the rear wall, a joining surface of the cylinder head to a head cover is formed on a plane crossing a cylinder axis, the plane being inclined downward toward a front. Rotation axes of camshafts are arranged on the plane. An axis of a valve stem of a throttle valve is arranged on the plane. A curve cover curved so as to cover driven sprockets fixed to the camshafts is formed on one side in a vehicle width direction of the head cover. A drum housing box housing a throttle drum fixed to one end of the valve stem is arranged close to the curve cover.

Abstract: In a DOHC-type internal combustion engine in which a pair of intake valves and a pair of exhaust valves are disposed around a plug hole, and two pairs of rocker arms are respectively interposed between intake-side and exhaust-side camshafts and the intake valves and the exhaust valves, first and second support portions of one pair of the rocker arms are disposed between the intake valves and the exhaust valves in a direction orthogonal to axes of the intake-side and exhaust-side camshafts and around the plug hole, and the third and fourth support portions of an other pair of the rocker arms are disposed outside a region between the intake valves and the exhaust valves in the direction orthogonal to the axes of the intake-side and exhaust-side camshafts.

Abstract: An optical measurement probe is a probe for guiding light generated from a measurement target to an appliance, and includes an optical window and an optical fiber. The optical window is formed in a columnar shape, one of end surfaces of which forms a reflection surface (tapered surface), the optical window transmitting light entering from an incident surface (flat surface) formed on a portion of an outer peripheral surface of the optical window, causing the light to be reflected by the reflection surface, and emitting the light from the other end surface. The optical fiber guides the light emitted from the other end surface of the optical window to the appliance.

Abstract: A cam chain tensioner device of an internal combustion engine includes a cam chain tensioner, and a tensioner lifter pressing the cam chain tensioner to a cam chain. The tensioner lifter is mounted on an inclined upper surface of the cylinder head. The cylinder head has therein a valve train oil supply passage supplying oil from an oil pump to the valve train camshafts, and a tensioner lifter oil supply passage supplying oil to the tensioner lifter. The valve gear oil supply passage has a branching portion where the tensioner lifter oil supply passage branches. The branching portion is at a position higher than the tensioner lifter, and communicates with the tensioner lifter disposed at a position lower than the branching portion. It is thus possible to prevent fluttering of the cam chain and to reduce noise generated by the cam chain at the time of restart of the engine after it is stopped.

Abstract: In an internal combustion engine for a saddle riding vehicle, in which a gear transmission and a shift drum of a shift change device is stored in a crankcase, the gear transmission having a plurality of transmission shafts parallel to a crankshaft extending in a vehicle width direction, a single pump shaft common to first and second oil pumps is rotatably supported by the crankcase. First oil pump rotors of the first oil pump are disposed at a mating face of a pair of left and right crankcase half bodies. A second oil pump rotor of the second oil pump is disposed between a pump gear and the first oil pump and at a side surface, on a side opposite to the mating face, of one crankcase half body out of the pair of left and right crankcase half bodies, the pump gear being arranged in the pump shaft.

Abstract: In a DOHC-type internal combustion engine in which a pair of intake valves and a pair of exhaust valves are disposed around a plug hole, and two pairs of rocker arms are respectively interposed between intake-side and exhaust-side camshafts and the intake valves and the exhaust valves, first and second support portions of one pair of the rocker arms are disposed between the intake valves and the exhaust valves in a direction orthogonal to axes of the intake-side and exhaust-side camshafts and around the plug hole, and the third and fourth support portions of an other pair of the rocker arms are disposed outside a region between the intake valves and the exhaust valves in the direction orthogonal to the axes of the intake-side and exhaust-side camshafts.

Abstract: Light from a direction (D) different from a predetermined direction is reflected by a tapered surface (21) so as to enter an optical fiber (4) for guiding light entering along the predetermined direction to an appliance. Light from the desired direction (D) may thereby be reflected by the tapered surface (21) according to the angle of the tapered surface (21) and may be made to enter the optical fiber (4). Accordingly, even in a case where the installation position of an optical measurement probe (1) is limited, if the angle of the tapered surface (21) is appropriately set, light from the desired direction (D) may be made to enter the optical fiber (4).

Abstract: In a saddle-ride type vehicle in which a cylinder head of a single-cylinder engine main unit has a front wall and a rear wall, an exhaust system being connected to the front wall and an intake system being connected to the rear wall, a joining surface of the cylinder head to a head cover is formed on a plane crossing a cylinder axis, the plane being inclined downward toward a front. Rotation axes of camshafts are arranged on the plane. An axis of a valve stem of a throttle valve is arranged on the plane. A curve cover curved so as to cover driven sprockets fixed to the camshafts is formed on one side in a vehicle width direction of the head cover. A drum housing box housing a throttle drum fixed to one end of the valve stem is arranged close to the curve cover.

Abstract: When start control is initiated, the start control device operates in a first operating mode in which an upper limit value of an engine speed is limited to a first upper limit value (NErev1) that is lower than an upper limit value (NErev0) in a non-start control. When an elapsed period of time after a throttle opening has exceeded a predetermined opening in the first operating mode reaches a predetermined standby time, the start control device operates in a second operating mode in which the upper limit value of the engine speed is limited to a second upper limit value (NErev2) that is lower than the first upper limit value. The start control device transitions to an ordinary mode to thereby terminate the start control when a period of time of the second operating mode reaches a predetermined control period of time or a forced cancellation condition holds.

Abstract: In an oil filter attaching structure for a vehicle-mounted internal combustion engine, an oil filter of the engine is installed in a filter case integrally formed with a crankcase cover of a crankcase. The crankcase cover is mounted on a side surface of the crankcase so as to cover an end of a crankshaft supported by the crankcase to extend in vehicle widthwise directions. An internal combustion engine accessory and a transmission clutch device are disposed inside of the crankcase cover in respective positions forward and rearward of the crankshaft. The oil filter and an oil supply port are disposed inside of the crankcase cover in respective positions upward and downward of the crankshaft. The oil filter attaching structure efficiently utilizes the space for making itself smaller in size and for better maintainability.

Abstract: There are provided a plug built-in type optical measurement probe capable of obtaining a more accurate measurement value, and an optical measurement device provided with the same. A spark section and a light receiving section are held by a plug main body while being arranged next to each other in a protruding manner such that an end face of a holder is arranged at a position where discharge light from the spark section does not enter the field of view of the light receiving section. Accordingly, the light receiving section can be held in a manner protruding from the plug main body, and entering of the discharge light from the spark section can be restricted by the holder of the light receiving section.

Abstract: Light from a direction (D) different from a predetermined direction is reflected by a tapered surface (21) so as to enter an optical fiber (4) for guiding light entering along the predetermined direction to an appliance. Light from the desired direction (D) may thereby be reflected by the tapered surface (21) according to the angle of the tapered surface (21) and may be made to enter the optical fiber (4). Accordingly, even in a case where the installation position of an optical measurement probe (1) is limited, if the angle of the tapered surface (21) is appropriately set, light from the desired direction (D) may be made to enter the optical fiber (4).

Abstract: There are provided an optical measurement probe capable of obtaining a more stable measurement result, and an optical measurement device provided with the same. An incidence surface of an optical window to be used in a high temperature environment is covered by a deposited film. The optical window is formed of sapphire, and the deposited film is formed from SiO2. Adhesion of dirt to the incidence surface, and an influence, on a measurement result, of the adhesion of dirt on the incidence surface can thereby be prevented, and a more stable measurement result can be obtained.

Abstract: There are provided an optical measurement probe capable of obtaining a more stable measurement result, and an optical measurement device provided with the same. An incidence surface of an optical window to be used in a high temperature environment is covered by a deposited film. The optical window is formed of sapphire, and the deposited film is formed from SiO2. Adhesion of dirt to the incidence surface, and an influence, on a measurement result, of the adhesion of dirt on the incidence surface can thereby be prevented, and a more stable measurement result can be obtained.

Abstract: There are provided a plug built-in type optical measurement probe capable of obtaining a more accurate measurement value, and an optical measurement device provided with the same. A spark section and a light receiving section are held by a plug main body while being arranged next to each other in a protruding manner such that an end face of a holder is arranged at a position where discharge light from the spark section does not enter the field of view of the light receiving section. Accordingly, the light receiving section can be held in a manner protruding from the plug main body, and entering of the discharge light from the spark section can be restricted by the holder of the light receiving section.

Abstract: To achieve further reduction in size and weight of a cylinder head in a four-cycle engine having a connection surface formed on the cylinder head to connect a head cover set so as to follow along a plane that is inclined so as to be spaced further away from a cylinder block toward a first side wall. A camshaft holder is integrally formed on a cylinder head so as to protrude from a connection surface as viewed from an axial direction of a camshaft. An intake port is disposed in the first side wall such that an upstream end thereof is disposed at the same position as part of the bearing portion in a direction along an axis of a cylinder bore. An exhaust valve has a stem end disposed at a position protruding from the connection surface as viewed in a direction along the axial direction of a camshaft.

Abstract: An exhaust control device for a vehicle engine wherein an exhaust pipe forms an exhaust passage along with an exhaust port is connected to a cylinder head via the exhaust port. A rotary valve is capable of changing the opening area of the exhaust passage. The rotary valve being disposed in approximately the middle of the exhaust passage. The opening area of the exhaust passage is made controllable by the rotary valve while avoiding an increase in the number of component parts. A rotary valve having a turning axis located at a position offset from the center of the exhaust port is housed in a valve housing provided integrally with a cylinder head.