Abstract: An internal combustion engine has intake (20) and exhaust (22) poppet valves, a first and a second set of cam lobes (64) for operating the intake and exhaust poppet valves (20,22) respectively, and a third set of cam lobes (68) for producing an additional selectable valve event in order to allow the engine to operate as a compression brake. The third set of cam lobes (68) and at least one of the first and second set of cam lobes (64) are rotatable relative to one another and form part of an assembled camshaft (60) so as to be rotatable about a common axis. A phasing system (50) acts on the assembled camshaft (60) to allow the phase of the third set of cam lobes (68) to be changed relative to the engine crankshaft.

Abstract: A rotary hydraulic coupling is described for use in an engine having a camshaft, a hydraulic phaser for driving the camshaft, and an oil feed manifold secured to the body of the engine and incorporating oil galleries for supplying oil to the phaser. The rotary coupling, which serves to connect the oil galleries of the oil feed manifold to rotating oil ducts which lead to hydraulic working chambers within the phaser, comprises a cylindrical first element rotatably received within and sealed relative to an annular second element, each of the first and second elements having bores that communicate with annular grooves in a mating surface of at least one of the two elements to establish fluid flow communication between the bores in the two elements, the bores in the first element being connected to axially extending oil passages formed within the first element.

Abstract: A camshaft assembly is disclosed which comprises an inner shaft, an outer tube surrounding and rotatable relative to the inner shaft, and two groups of cam lobes mounted on the outer tube, the first group of cam lobes being fast in rotation with the outer tube, the second group being rotatably mounted on the outer surface of the tube and connected for rotation with the inner shaft. The connection between the second group of cam lobes and the inner shaft is effected by means of driving members whose positions are adjustable in order to compensate for significant manufacturing inaccuracies between the inner shaft and its associated group of cam lobes.

Abstract: An assembly is provided comprising an SCP camshaft (130) having an inner shaft (140) and an outer tube (124) and a hydraulically operated twin vane phaser (110) having two output members (114, 116) coupled respectively for rotation with the inner shaft (140) and the outer tube (124) of the SCP camshaft (130). Each of the output members (114, 116) of the twin phaser is axially clamped to a respective one of the inner shaft (140) and the outer tube (124)of the SCP camshaft (130). A support bearing (150) for the twin vane phaser (110), having passageways (142) for supplying pressure medium to working chambers of the twin vane phaser (110), is formed separately from the SCP camshaft (130).

Abstract: A variable phase mechanism is described which comprises a drive member rotatable about an axis, first and second driven members rotatable in synchronism with the drive member, an actuator for rotating the first driven member relative to the drive member to vary the phase of rotation of the first driven member relative to the drive member, and a yoke coupling the second driven member for rotation with one of the drive member and the first driven member and movable transversely relative to the axis of the drive member to vary the phase of rotation of the second driven member relative to the drive member. In the invention, transverse movement of the yoke is effected by means of interaction between the other of the drive member and the first driven member and a radially outwards facing surface defined by the yoke.

Abstract: An actuating system for a gas exchange valve of an internal combustion engine is described which comprises two cams (12,14) associated with the valve (10), a summation linkage (22,24,30,32) for lifting the valve in dependence upon the sum of the instantaneous lifts of the two cams (12,14). A de-activating mechanism 34 is provided for selectively decoupling the summation linkage from one (12) of the two cams.

Abstract: An internal combustion engine is described having a valve mechanism that comprises an SCP camshaft operating two sets of valves. The first set of valves is operated via a summation rocker system such that the valve lift characteristic results from the combination of two cam profiles. The second set of valves has a valve lift characteristic that is different from that of the first set. In the invention, changing the valve lift characteristic of the first set of valves by varying the phase of the inner shaft of the SCP camshaft relative to the outer tube of the SCP camshaft serves additionally to alter the operation of the second set of valves.

Abstract: A variable phase drive coupling is described for providing drive from an engine crankshaft to two sets of cams. The drive coupling comprising a drive member 12 connectable for rotation with the engine crankshaft and two driven members 18, 20 each connectable with a respective one of the two sets of cams. In the invention, the angular relationship of each of the driven members 18, 20 is independently variable relative to the drive member 12 under the action of camshaft torque reversals.

Abstract: The invention relates to a camshaft assembly comprising an inner shaft, an outer tube rotatable relative to the inner shaft, and two groups of cams mounted on the outer tube, the first group of cams being fast in rotation with the outer tube, and the second group being rotatably mounted on the outer surface of the tube and being connected for rotation with the inner shaft by means of connecting members that pass through circumferentially elongated slots in the outer tube. In the invention, the outer tube surrounds the inner shaft with clearance and the members connecting different ones of the cams of the second group to the inner shaft are inclined relative to one another and act to locate the axis of the inner shaft relative to the outer tube.

Abstract: A method disclosed for mounting a camshaft and a phaser on an engine, the camshaft being an SCP camshaft formed of concentric inner and outer rotary members each fast in rotation with a respective one of two groups of cams and the phaser enabling the phase of at least one of the rotary members of the camshaft to be varied dynamically relative to the phase of the engine crankshaft and the other rotary member. The method comprises first securing the phaser 30 to one end of the camshaft 10, then mounting the camshaft and phaser as a sub-assembly to the engine, and subsequently securing to the engine an abutment 40 for limiting the axial displacement of the camshaft relative to the engine.

Abstract: A rotary hydraulic coupling is described for use in an engine having a camshaft, a hydraulic phaser for driving the camshaft, and an oil feed manifold secured to the body of the engine and incorporating oil galleries for supplying oil to the phaser. The rotary coupling, which serves to connect the oil galleries of the oil feed manifold to rotating oil ducts which lead to hydraulic working chambers within the phaser, comprises a cylindrical first element rotatably received within and sealed relative to an annular second element, each of the first and second elements having bores that communicate with annular grooves in a mating surface of at least one of the two elements to establish fluid flow communication between the bores in the two elements, the bores in the first element being connected to axially extending oil passages formed within the first element.

Abstract: A gas exchange valve of an internal combustion engine, has valve lifting movements with valve displacement curves and a control unit. To this end, a control unit is provided for operation of at least one valve, in particular a gas exchange valve of an internal combustion engine, in which the valvelifting movement of the at least one valve (6) is generated by superimposing two synchronously rotating cam profiles acting mechanically on a lift operating element (4). The two cam profiles (1, 2) have specially shaped areas by means of which, when superimposed to form one of the two cam profiles (1, 2), at least one additional valve displacement (ZV) can be generated on the whole in addition to a main valve displacement movement (HV) over a full revolution of each of these cam profiles (1, 2).

Abstract: A mechanism for actuating an engine poppet valve includes two rotatable cams, a first rocker mounted on a pivot shaft and acting between a first of the two cams and the stem of the valve, and a second rocker mounted for rotation about a fixed axis and acting between the second of the two cams and the pivot shaft of the first rocker to raise and lower the pivot axis of the first rocker cyclically in synchronism with the rotation of the second cam, whereby the valve is operated in dependence upon the instantaneous sum of the lifts of the two cams.

Abstract: An engine is described having a camshaft 10 formed of an inner shaft 12 and an outer tube 14 both of which rotate with respective groups of cams 18 and 16. A drive train driving both the inner shaft 12 and the outer tube from the engine crankshaft includes a phaser 30 for enabling the phase of at least one of the groups of cams 16 and 18 to be varied dynamically relative to the phase of the crankshaft. The phaser is secured to the front end of the outer tube 14 and the inner shaft 12 of the camshaft 10 is connected to the front side 36 of the phaser 30 by way of a driving member 46 that encloses the component 40 securing the phaser to the outer tube 14 of the camshaft 10.

Abstract: An engine is described having two camshafts 14, 16 each of which carries two groups of cams and comprises an inner shaft coupled for rotation with a first group of cams and an outer tube rotatably supported by the inner shaft and coupled for rotation with the second group of cams. A phaser 12 is provided to enable the phase of at least one of the two groups of cams on one of the SAP camshafts 14, 16 to be varied with reference to the phase of the engine crankshaft. Drive links in the form of meshing gear wheels, drive chains or belts, couple the two corresponding groups of cams on the respective camshafts for rotation in unison with one another.

Abstract: A twin vane-type phaser is described which is provided with a locking mechanism for locking the drive member to the driven members when the pressure in the working chambers is a below is predetermined value. The locking mechanism comprises two coaxial locking pins 114, 118 mounted in a common bore 110 in the centrally located member 32. The locking pins are resiliently urged apart by a spring 120 into bores in the two outer members 38, 40 and are retracted by pistons 112, 116 when the hydraulic pressure in the working chambers attains the predetermined value.

Abstract: A camshaft assembly includes an inner shaft, an outer tube surrounding and rotatable relative to the inner shaft, and two groups of cam lobes mounted on the outer tube. The first group of cam lobes is fast in rotation with the outer tube and the second group is rotatably mounted on the outer tube and connected for rotation with the inner shaft by means of pins that pass with clearance through slots in the outer tube. A spring is incorporated in the camshaft assembly to bias the inner shaft relative to the outer tube towards one extreme of its angular range.

Abstract: A valve operating mechanism is described for an internal combustion engine in which at least one valve (14) of an engine cylinder is operated by two cams (10,12). The cams (10,12) have respective cam followers (38,36) which are resiliently biased to remain in contact with the cams (10,12) at all times and which act on the valve (14) by way of a summation linkage (20,24) in such a manner that the displacement of the valve (14) at any instant is determined by a combination of the displacements of the two cam followers (38,36). In the invention, movement of each of the two cam followers (38,36) is transmitted to the summation linkage (20,24) by way of a respective one of two pushrods (28,30).

Abstract: A hydraulic phase shifting mechanism is described for an engine camshaft subjected to torque fluctuations during operation. The mechanism employs a magnetorheological fluid as a hydraulic pressure medium and is controlled by selective application of a magnetic field to vary the flow properties of the magnetorheological fluid.

Abstract: An engine is described having a camshaft 14 formed with an oil passage 26, a cover 22 fitted to the front of the engine and overlying the front end of the camshaft 14, and an oil supply line 24 formed in the engine front cover. The camshaft 14 is formed with an axially projecting extension that is rotatably and sealingly received in an opening formed in the front cover 22 to enable the oil passage 26 in the camshaft to communicate with the oil supply line 24 in the engine cover 22.