Abstract: A pair of valve-timing controlling oil passages leading to a second valve-operating characteristic changing mechanism are defined in a lower camshaft holder, and a valve lift controlling oil passage leading to a first valve-operating characteristic changing mechanism is defined between the pair of valve-timing controlling oil passages in a mating surface of the lower camshaft holder with a cylinder head. In an area where the width of the valve lift controlling oil passage is reduced in order to avoid the interference with the valve-timing controlling oil passages, the depth of the valve lift controlling oil passage is larger than that in the other positions, whereby a sectional area of the oil passage is secured. Thus, the oil passages leading to the first and second mechanisms can be formed compact in a camshaft support member.

Abstract: A method of controlling resonances in timing drive systems for internal combustion engines having variable cam timing systems using cam phasers with the capability of being locked in position. Locking or unlocking the phaser changes the resonant characteristics of the timing drive system. The invention uses these changes in characteristics between locked and unlocked phasers to minimize the effects of resonance in timing drives by changing between locked and unlocked states as engine RPM passes through resonant points.

Abstract: A valve driving apparatus includes a magnetic flux generating element in which an electromagnetic coil is wound to generate magnetic flux, a magnetic field generating element which has at least two poles to distribute magnetic flux and form at least one magnetic field region, a drive means which includes a magnetic path member, and a magnetized member arranged in accordance with the magnetic field region and having two magnetized faces with mutually different polarity to be connected and moved together with a valve rod united with a valve element. A current supply means supplies driving current to the electromagnetic coil whereby the current has polarities corresponding to either a valve closing direction or a valve opening direction of the valve element. The apparatus reduce impact of valve seating with a simple structure and controls the valve with less power consumption and with precision.

Abstract: A rocker arm assembly has a rocker arm that forms an adjusting mechanism bore, an insert bore, and a transverse central bore. An adjusting mechanism, e.g., a screw, is installed in the adjusting mechanism bore and is used to adjust the travel of the rocker arm as it pivots about the central bore during normal operation. An insert having a hemispherical end is installed in the insert bore. Additionally, a button that forms a hemispherical chamber that is sized and shaped to be received to the hemispherical end of the insert is press fitted onto the insert. As the rocker arm assembly pivots about the central bore the button rotates with respect to the insert. The cooperation of structure between the insert and the button allows the button to rotate with respect to the insert, but prevents the button from falling off the insert and damaging the engine in which the rocker arm assembly is installed.

Abstract: An internal combustion engine has an intake valve control device for controlling at least intake valves. The control device comprises a first mechanism which varies a working angle of the intake valve; a second mechanism which varies an operation phase of the intake valve; and a control unit which controls both the first and second mechanisms in accordance with an operation condition of the engine. The control unit is configured to carry out controlling variation in the open timing of the intake valve effected by the first mechanism to be larger than variation in the open timing of the intake valve effected by the second mechanism.

Abstract: A valve drive mechanism is provided that has a rocker arm that by means of a swivel joint is movable about a pivot axis that extends transverse to the rocker arm. A control unit serves to actuate one end of the rocker arm, the other end of which actuates a poppet valve. A guide element, which is disposed between the end of the valve stem of the poppet valve and the other end of the rocker arm, serves to secure the position of the other end of the rocker arm relative to the valve stem end. The guide element is separate from the rocker arm and valve stem, and the other end of the rocker arm comes to rest between abutment surfaces of the guide element.

Abstract: A control system for an electromagnetic actuator actuates an intake or exhaust valve. The actuator includes first and second electromagnets which develop an electromagnetic attraction force the strengths of which depend on the amount of current supplied thereto. A spring biases an armature between the electromagnets to a neutral position therebetween. The control system comprises a control circuit which (a) controls the amount of current supplied to the first electromagnet thereby restricting a moving velocity of the armature, at a first stage in a course of changing the armature from a first position to a second position; and (b) supplies current to the second electromagnet at a timing at which the armature approaches the second electromagnet upon the biasing force of the spring thereby attracting the armature to the second position, at a second stage in the course of changing the armature from the first position to the second position.

Abstract: A catheter (10, 10′, 10″, 10′″), in particular for insertion into blood vessels of the human body, having at least one sensor (32) which is arranged at the distal end (12) of the catheter (10, 10′, 10″, 10′″) and which is adapted to pick up a spacing signal which is dependent on the spacing of the sensor (32) with respect to the vessel wall, and control means (36, 36′, 36″) which are connected to the sensor for taking over the spacing signal.

Abstract: An electromagnetic actuator for intake or exhaust valves of an internal combustion engine, in which an oscillating arm has an end in abutment on the upper end of the stem of the intake or exhaust valve; two electromagnets being provided to move the oscillating arm so as axially to displace this valve; a frame supporting the arm being connected to the head of the engine so as to be able to oscillate about an axis perpendicular to the axis of movement of the intake or exhaust valve and the electromagnetic actuator being provided with a device for adjusting the position of the frame with respect to the head to rotate the frame so as to maintain the mechanical play between the end of the oscillating arm and the stem of the valve at a predetermined value.

Abstract: A valve drive mechanism is provided for an internal combustion engine, especially a four-stroke engine in a power chain saw. The implement housing is spanned by a front handle, the tubular grip of which is adjacent to the cylinder head of the engine and extends from one longitudinal side of the implement to the other longitudinal side thereof. A rocker arm of a valve control is pivotably mounted on the cylinder head between the ends of the rocker arm, with the rocker arm being pivotable about a pivot axis disposed transverse to the rocker arm. Push rods of a control mechanism engage one end of the rocker arm to actuate a poppet valve, on the valve stem of which the other end of the rocker arm acts. To be able to guide the tubular grip close to the center of gravity of the implement, the longitudinal axis of the rocker arm is disposed approximately parallel to the adjacent portion of the tubular grip.

Abstract: A retainer clip includes a U-shaped body, first and second legs, and a resilient segment interconnecting first ends of the legs. The legs are adapted to resiliently engage opposite sides of a wall of a rockable actuator member. A second end of the first leg includes a guide recess having a clip edge. A second end of the second leg includes a gripping recess and opposing resilient edges adapted to frictionally grip opposite sides of a cylindrical member engaged with a socket in a second side of the wall. The resilient edges frictionally grip the cylindrical member at points on an axis intersecting and normal to the axial center line of the cylindrical member. The retainer clip is adapted to frictionally retain the cylindrical member in the socket to thereby form a subassembly for installation in a valve train.

Abstract: A camshaft drive mechanism for a vee-twin engine is described. The mechanism comprises first and second camshafts which are driven by a gear on the crankshaft of an engine incorporating the mechanism. The crankshaft drive gear engages a primary (idler) gear on the first camshaft while a secondary gear on that camshaft imparts counter rotation on the second camshaft via an identical secondary gear on the latter camshaft.

Abstract: An internal combustion engine and method are capable of reducing a power consumption required to open an exhaust-side electromagnetic valve at a predetermined time. This internal combustion engine includes an electromagnetic valve drive mechanism that controls an exhaust valve of the internal combustion engine to open and close by using electromagnetic force generated in response to application of a magnetizing current, and a controller that controls the electromagnetic valve drive mechanism. The controller changes, under predetermined conditions, an open timing of the exhaust valve so as to reduce the power consumption of the electromagnetic valve drive mechanism.

Abstract: It is determined whether the current operation condition is in a transitional or steady state. If the operation condition is in a transitional state, then the transition gain is obtained by multiplying the transition base gain that is calculated corresponding to engine speed with a map by a transition degree correction coefficient. If the operation condition is in a steady state, the steady-state gain is set to the steady-state gain that is calculated corresponding to the engine speed. Subsequently, the control magnitude OCVC of the oil pressure control valve is obtained by multiplying the difference between the target advance angle and the actual advance angle by the gain.

Abstract: In a valve-operating mechanism in a 4-cycle engine, a timing transmitting device is disposed on one side of an engine body. A cam device includes a cam coupled to a driven pulley of the timing transmitting device on one side of a cylinder head, intake and exhaust rocker shafts rotatably carried in the cylinder head, intake and exhaust cam followers secured to one ends of the rocker shafts with their tip ends in sliding contact with the cam, and intake and exhaust rocker arms secured to the other ends of the intake and exhaust rocker shafts with their tip ends abutting against the intake and exhaust valves. Thus, the cam of the cam device can be disposed on one side of the cylinder head to effectively reduce the entire height of the engine.

Abstract: A valve control system for an internal combustion engine includes a housing comprising a cylinder defining a longitudinal axis, an exhaust port, a piston disposed in the cylinder and an engine valve operably connected to the piston. An exhaust member is disposed in the housing and is variably moveable along a longitudinal path to a desired position between a maximum and minimum lift position. The exhaust member has an exhaust port that is maintained in communication with the housing exhaust port as the exhaust member is selectively, variably moved between the maximum and minimum lift positions. A pressure source selectively applies a pressure to the piston and a control system is operably connected to the exhaust member and selectively, variably moves the exhaust member between the maximum and minimum position. A method for controlling the engine valve is also provided.

Abstract: An adjustable camshaft sprocket assembly for attachment to a camshaft. A camshaft sprocket is removably securable to a camshaft sprocket hub and moveable, independent of the camshaft sprocket hub when the camshaft sprocket assembly is mounted on the camshaft. An adjustment tool is used to adjust the camshaft sprocket comprising at least two extensions. The first extension is of a size to fit within one a corresponding opening in the camshaft hub. The second extension is of a size to pass though a different corresponding opening in the camshaft hub and fit within a corresponding opening in the camshaft sprocket. A handle extension is used for turning the adjustment tool about the second extension, which serves as a pivot.

Abstract: An electromagnetic valve actuator (EVA) for actuating movement of a valve in a vehicle engine includes a valve assembly operatively connected to the valve for movement therewith. The valve assembly includes a shaft connected to the valve. Two armature plates are operatively associated with the shaft, and each armature plate includes a permanent magnet. An electromagnetic coil is positioned between the two armature plates for selectively electromagnetically pushing and pulling the armature plates. Two springs are engaged with the two armature plates, respectively, for biasing the armature plates in opposing directions. The permanent magnets are operative to assist the electromagnetic coil in holding the valve in a desired position to reduce power consumption or assisting in repelling the armature for accelerating valve opening or closing.

Abstract: An apparatus controls valve timing of an internal combustion engine that is provided with helical splines of an actuator for varying a phase difference in rotation and an actuator for varying a cam profile and lift of an intake cam. When the apparatus for controlling valve timing and respective actuators are not driven, a valve timing can be automatically established, which can achieve a cold valve overlap &thgr;ov. Carburetion of fuel can be promoted in the combustion chamber and intake ports by the blow-back of exhaust resulting from the cold valve overlap &thgr;ov. A mixture is made into a sufficient air-fuel ratio without depending on an increase in fuel when cold idling, wherein combustion is stabilized still more than in a case where valve overlap is not increased, cold hesitation can be prevented from occurring, and drivability can be maintained in a comparatively favorable state.

Abstract: In a camshaft timing device for an internal combustion engine having a camshaft driven from a driveshaft by way of a camshaft drive which is capable of advancing or retarding the camshaft and therefore the valve timing, the camshaft drive is mounted onto the camshaft by a clamping screw which has a cylindrical opening in which a valve spool is movably disposed for controlling admission of hydraulic fluid to, and its release from, the camshaft drive, the valve spool being actuated by an electromagnetic motor acting against a valve spring biasing the valve spool in one direction for controlling the operation of the hydraulic camshaft drive and the valve spool is pressure balanced for accurate positioning control thereof.