Abstract: An engine valve operating system is provided in which a roller in rolling contact with a valve operating cam of a camshaft is axially supported via a roller shaft on a roller support portion provided on a first rocker arm, a second rocker arm having a cylindrical boss portion pivotably supported on a support shaft and an arm portion extending from the boss portion and having a sliding surface that is in sliding contact with the roller shaft is operatively connected to an engine valve, and the position of either one of first and second rocker arm swing axes is changed within a plane perpendicular to the axis of the camshaft, wherein at least the roller support portion (38) of the first rocker arm (23) is disposed at a position that overlaps the second rocker arm (26A, 26B) in plan view. This can provide an engine valve operating system that enables the size thereof to be reduced in a direction along the axis of the camshaft.

Abstract: An engine valve operating system is provided in which a roller in rolling contact with a valve operating cam of a camshaft is axially supported via a roller shaft on a roller support portion provided on a first rocker arm, a second rocker arm having a cylindrical boss portion pivotably supported on a support shaft and an arm portion extending from the boss portion and having a sliding surface that is in sliding contact with the roller shaft is operatively connected to an engine valve, and the position of either one of first and second rocker arm swing axes is changed within a plane perpendicular to the axis of the camshaft, wherein at least the roller support portion (38) of the first rocker arm (23) is disposed at a position that overlaps the second rocker arm (26A, 26B) in plan view. This can provide an engine valve operating system that enables the size thereof to be reduced in a direction along the axis of the camshaft.

Abstract: A core of a solenoid actuator is provided which is improved in durability, and at the same time ensures high energy efficiency of the solenoid actuator. The core of the solenoid actuator attracts an armature during operation of the solenoid actuator. A plurality of core plates are formed of a magnetically soft material and laminated in a predetermined direction orthogonal to a direction of attracting the armature to form a laminated stack. The core plates form magnetic circuits between the armature and the core plates themselves during the operation of the solenoid actuator. Two core holders formed of a non-magnetic material sandwiches the laminated stack of the plurality of core plates from opposite sides along the predetermined direction. The plurality of core plates are each coated with insulating film, which insulate adjacent two core plates from each other.

Abstract: An electromagnetic actuator is equipped with two springs which act in opposite directions, and an armature that is connected to the springs and is supported in an unactivated state in a neutral position provided by the two springs. The armature is coupled to a mechanical element such as a valve of an engine. The actuator includes a pair of electromagnets that drive the armature between a first terminal position and a second terminal position, and a power supply device that controls the voltage supplied to the electromagnet attracting the armature to a constant voltage when the armature is driven from one of the terminal positions to the other terminal position. The voltage supplied to the electromagnets is maintained at a constant value and the larger current flows in the larger is the gap between the armature and the yoke and smaller is the counter electromotive force.

Abstract: A solenoid-operated valve for use in an internal combustion engine has a valve body movable into and out of abutment of an intake/exhaust port in the internal combustion engine to close and open an intake/exhaust passage in communication therewith, a movable plate connected to the valve body by a transmission valve stem, a first solenoid for magnetically attracting the movable plate to cause the valve body to close the intake/exhaust port, and a second solenoid disposed in confronting relation to the first solenoid with the movable plate interposed therebetween, for magnetically attracting the movable plate to cause the valve body to open the intake/exhaust port. A piston is movable in a cylinder in unison with the transmission valve stem until the valve body closes the intake/exhaust port when the first solenoid magnetically attracts the movable plate to position the valve body closely to the intake/exhaust port.

Abstract: A solenoid-operated valve for use in an internal combustion engine has a valve body movable upwardly for closing an exhaust or intake passage and movable downwardly for opening the exhaust or intake passage, a valve stem extending upwardly from the valve body, a pair of upper and lower solenoids spaced from each other in an axial direction of the valve stem and confronting each other vertically, the valve stem extending through the upper and lower solenoids, a movable plate mounted on the valve stem and disposed between the solenoids, the movable plate being movable between the solenoids to cause the valve stem to open and close the valve body in response to being magnetically attracted by the solenoids, a first spring for normally biasing the valve body to open the exhaust or intake passage, and a second spring for normally biasing the valve body to close the exhaust or intake passage against the first spring. The first spring has a resilient force greater than a resilient force of the second spring.

Abstract: A valve operating system in an internal combustion engine, that can be readily assembled and installed on the engine, including a casing coupled to an upper surface of a cylinder head, an armature, a pair of electromagnets for exerting electromagnetic forces on the armature in directions of opening and closing of an engine valve, and a pair of resilient means for biasing the engine valve in the opening and closing directions, respectively, and for retaining the armature at a predetermined neutral position by cooperation with each other during deenergization of both the electromagnets. The resilient means for closing the engine valve is mounted between a retainer fixed to the valve stem and a fixed position on the cylinder head, and the electromagnets are fixed within the casing which is constructed so that an upper portion of the stem can be inserted into the casing.

Abstract: A valve operating mechanism for an internal combustion engine for varying the operation of the valve dependent on engine operating conditions. A first rocker arm movable to follow a first cam and a second rocker arm movable to follow a second cam corresponding to a higher speed operating condition than that of the first cam are pivotally supported on a rocker arm shaft. A first connection switching device capable of switching the connection and disconnection between the third and first rocker arms and a second switching device capable of switching the connection and disconnection between at least one of the first and third rocker arms and the second rocker arm independently from the first connection switching device, are disposed at locations displaced circumferentially relative to the rocker arm shaft.

Abstract: An SOHC-type valve operating system in an internal combustion engine having a single cam shaft commonly provided for a pair of intake valves and a pair of exhaust valves. A plurality of intake valve driving members are rockably disposed between the cam shaft and the pair of intake valves and have an operative-connection switchover mechanism for switching over the connection and disconnection of the intake valve driving members. A pair of exhaust valve driving members are rockably disposed between the cam shaft and the pair of exhaust valves and independently operate each of the exhaust valves. The operative-connection switchover mechanism includes a switchover pin movable between a position for operatively connecting adjacent intake valve driving members and a position for releasing such connection, which pin is slidably mounted in a cylindrical sleeve secured to the intake valve driving members for guiding the movement of the switchover pin.

Abstract: A valve operating mechanism for an internal combustion engine for varying the operation of the valve dependent on engine operating conditions. A first rocker arm movable to follow a first cam and a second rocker arm movable to follow a second cam corresponding to a higher speed operating condition than that of the first cam are pivotally supported on a rocker arm shaft. A first connection switching device capable of switching the connection and disconnection between the third and first rocker arms and a second switching device capable of switching the connection and disconnection between at least one of the first and third rocker arms and the second rocker arm independently from the first connection switching device, are disposed at locations displaced circumferentially relative to the rocker arm shaft.

Abstract: In an internal combustion engine comprising a valve operating system connected to a pair of intake valves and arranged to open one of the intake valves only in a very small amount such that the one intake valve is brought into its substantially inoperative state, in a suction stroke mainly in a low speed rotation region of the engine, a fuel injection valve capable of injecting fuel toward a pair of intake ports independently corresponding to the intake valves, and a control means for controlling the operation of the fuel injection valve, the control means is arranged to control the fuel injection valve with a fuel injection completion time determined within a suction stroke, when the one intake valve is in the substantially inoperative state.

Abstract: A valve operating system in an overhead cam type multicylinder internal combustion engine having three intake-side rocker arms disposed to operate a pair of intake valves and two exhaust-side rocker arms disposed to operate a pair of exhaust valves. The intake-side rocker arms are provided with a connection switchover mechanism capable of switching-over the connection and disconnection of the adjacent in take-side rocker arms. Exhaust-side cams are provided on a cam shaft on opposite sides of intake-side cams which are provided adjacent one another. Two of the intake-side rocker arms and both of the exhaust-side rocker arms are in rolling contact with the corresponding cams through rollers mounted on the rocker arms. The exhaust-side a rocker arms are provided with notches in the area near the cam shaft for accommodating portions of the intake-side rocker arms, respectively.

Abstract: A SOHC type internal combustion engine includes a pair of intake valves and a pair of exhaust valves. The intake valve driving means comprises a plurality of rocker arms disposed adjacent one another, including a pair of driving rocker arms operatively connected separately to the intake valves and a connection switchover mechanism capable of switching-over the connection and disconnection of the adjacent rocker arms in accordance with the operational condition of the engine. The exhaust valve driving means comprises a pair of exhaust valve-side rocker arms operatively connected separately to the exhaust valves and disposed on opposite sides of the intake valve driving means in positions opposed to said cam shaft, respectively. In the intake valve driving means, the opening and closing mode of the intake valves can be changed in accordance with the operational condition of the engine by operation of the connection switchover mechanism, thereby providing an improvement in output from the engine.