Abstract:
An internal combustion engine with a device for cyclically varying the speed of rotation of a cam for gas exchange control comprises a shaft (1) and an axis of rotation (5), a rotary body (2) rotatably supported on said shaft (1), wherein the speed of rotation of the rotary body (2) corresponds to the speed of rotation of the cam, and an intermediate member (4) rotatably supported in a plane perpendicular to said axis of rotation (5) of said shaft (1), wherein said rotary body (2) is rotated cyclically in relation to said shaft (1) if the axis of rotation of the intermediate member (4) is staggered in relation to the axis of rotation (5) of the shaft (1). The intermediate member (4) is rotatably supported on an outer eccentric element (40) which is rotatably supported on an eccentric seat (32) of an inner eccentric element (30). The shaft (1) extends through a bore (33) of the inner eccentric element (30), through the outer eccentric element (40) and through the intermediate member (4) and the inner eccentric element (30) has an outer surface (37) concentric with the center line of the bore (33) and arranged in such a way that the outer surface (37) and the bearing (50) lie in a common plane perpendicular to the axis of rotation (5) of the shaft (1).
Abstract:
A variable valve driving mechanism is provided with an eccentric member (14) having an annular eccentric portion (15), which is eccentric relative to a camshaft (11), and arranged on an outer periphery of the camshaft (11); an intermediate rotating member (16) having a first groove portion (16A) and second groove portion (16B), which extend in radial directions, and rotatably supported on the eccentric portion (15); a cam lobe (12) having a cam portion (6) for opening and closing an intake valve or exhaust valve (2) and arranged concentrically with and rotatable around the camshaft (11) and for rotation relative to the camshaft (11); a first pin member (17,23) slidably fitted at one end thereof in the first groove portion (16A) and connected at opposite end thereof to the camshaft (11) so that rotation of the camshaft (11) is transmitted to the intermediate rotating member (16); a second pin member (18,24) slidably fitted at one end thereof in the second groove portion (16B) and connected at opposite end thereof to the cam lobe (12) so that rotation of the intermediate rotating member (16) is. transmitted to the camshaft (11); and eccentric position adjusting means (30) for rotating the eccentric member (14) in accordance with a state of operation of the internal combustion engine.
Abstract:
According to a control strategy, a cylinder valve control device is monitored and operation of the engine is modified. The cylinder valve control device includes a driving shaft driven by the engine to drive an intermediate member which in turn drives a cam arranged to open an engine intake valve, and a driver which is operative in response to a command to vary an amount of eccentricity of the intermediate member with respect to a shaft axis of the driving shaft. During one mode of engine operation, the intermediate member is supported in a support for rotation about an axis in eccentric condition with respect to the shaft axis to accelerate and decelerate the cam with respect to rotation of the driving shaft. During another mode of engine operation, the intermediate member is in concentric condition with respect to the shaft axis to provide a synchronous motion of the cam with rotation of the driving shaft. In response to the eccentricity of the intermediate member, the engine operation is modified.
Abstract:
A device is proposed which enables a cam controlling an internal combustion engine valve to be moved relative to its driving shaft. A drive member is rotatable with a driving shaft, and a cam for co-axial rotation relative to the driving shaft. An intermediate member is mounted in a support for rotation so as to rotate eccentrically with respect to an axis of the driving shaft. The support is held for movement within a plane perpendicular to the shaft axis. A control rod is drivingly associated with the support and driven by an actuator.
Abstract:
An engine valve control mechanism is disclosed in which the eccentricity of an intermediate member can be varied by a pivotable support and a valve lift of a cylinder valve is varied in response to the varying eccentricity such that a reduced valve lift is produced during operation with the intermediate member held eccentric with a driving shaft which drives, via the intermediate member, a cam which actuates the valve.
Abstract:
A driving connection between a hollow camshaft (1) and its driving shaft (5) located within it, the axes (3, 8) of these two members being parallel but laterally displaceable to vary the characteristics of rotation of the camshaft in response to constant-speed rotation of the driving shaft. The camshaft supports a slideway (11) in which moves a slider (12) which makes a rotary joint with the end of an arm (15) carried by the driving shaft. The geometry of the arm is such that the center of rotation (18) of the rotary joint lies within the outline of the periphery of the driving shaft (5) when viewed along its axis (8), thus promoting radial compactness. The essential component of the arm may be an item (15) of crescent-shaped cross-section, the concave surface (19) of the crescent registering with the surface of the driving shaft.
Abstract:
A means of varying both the opening and closing angle of internal combustion engine valves by means of a mechanism which varies the instantaneous phase of the camshaft with respect to the phase of the crankshaft so causing the cam to spend a longer or shorter time than nominal in contact with the valve tappet in response to a chosen control programme.
Abstract:
Timing apparatus for a four-stroke engine with at least a shaft (2) of cams (7) located over the head of the cylinders and with the cams (7) acting directly on the valves (4), wherein the rotary motion of each shaft (2) of cams (7) is derived from a transmission shaft (1) parallel to the camshaft and driven by the engine crankshaft through a pair of identical gears (3,30) which are eccentrically keyed, one (3) on the transmission shaft (1) and the other (30) on the shaft (2) of cams (7), and are also 180.degree.-out-of-phase to one another, and with the cam (7) which is provided for the opening of the relevant valve (4) keyed on the shaft (2) of cams (7) having the maximum radius (r2) lift in phase with the minimum radius (R2) of rotation of the corresponding gear (30) eccentrically keyed on he same shaft (2) of cams (7).
Abstract:
A device for impulsively varying the timing of the rotation of a camshaft (1) relative to a driving sprocket wheel (14) mounted on a stubaxle (102) comprises followers (119,110) rotatable with respective follower shafts (103,104) mounted on the sprocket wheel (14) for rotation about axes parallel to the axis of rotation of the sprocket wheel and rotatable with the sprocket wheel; the follower shafts carrying planet gears (106,108) operative to transmit rotational movement in phase from the sprocket wheel to the camshaft via sun gear (107); and, an annular cam (117), whose angular position is adjustable by means of a worm wheel (112) and worm (111) arrangement, has an internal profile with which the followers (119,110) are held in engagement and which imparts periodic rotational movement to the follower shafts to carry the phase of the movement transmitted to the camshaft in a pulsed fashion.
Abstract:
An internal combustion engine has n member of cylinders, a piston in each cylinder connected to a crankshaft (2), each piston being in phase or out of phase with the others by A.degree. or a multiple thereof (A=720/n), cams for actuating inlet and exhaust valves to each cylinder, and a cam drive mechanism (5) which rotates the cams in phased relationship with the crankshaft (2) to open the valves in sequence for a desired angle of rotation of the crankshaft. The cam drive mechanism also includes means for combining the rotational movement of the cams with a phased oscillatory movement of the camshaft (3) and cams of variable amplitude about the axis of rotation at a frequency f times the crankshaft frequency so that over the period which the valves are opened and/or their timings variable, f has the following values:f=2n when the number of cylinders n=1;f=n or n/2 when n=2;and f=n/2 when n=3 or more. The selection of the frequency of the oscillations allows all the cams to be mounted on the same camshaft.