Abstract: A variable phase drive mechanism is described for providing drive from an engine crankshaft to two sets of cams. The drive mechanism comprises a drive member 32 connectable for rotation with the engine crankshaft and two driven members 38 and 40, each connectable for rotation with a respective one of the two sets of cams. Each of the driven members 38, 40 is connected by a vane-type hydraulic coupling for rotation with the drive member 32. The hydraulic coupling between the drive and driven members is such as to enable the angular position of each of the driven members 38 and 40 to be varied relative to the drive member 32 independently of the other driven member.

Abstract: A variable phase drive mechanism is described for providing drive from an engine crankshaft to two sets of cams. The drive mechanism comprises a drive member 32 connectable for rotation with the engine crankshaft and two driven members 38 and 40, each connectable for rotation with a respective one of the two sets of cams. Each of the driven members 38, 40 is connected by a vane-type hydraulic coupling for rotation with the drive member 32. The hydraulic coupling between the drive and driven members is such as to enable the angular position of each of the driven members 38 and 40 to be varied relative to the drive member 32 independently of the other driven member.

Abstract: A valve actuating mechanism is disclosed which comprises a valve (12), a camshaft having a cam (22) of fixed profile associated with the valve (12), a valve lifting rocking cam (24) pivotable about a fixed axis and having a contoured surface that acts to open and close the valve (12) as the rocking cam (24) pivots about said fixed axis, and a cam following rocker (26) comprising a cam follower (46) in contact with the fixed profile cam (22) on the camshaft and coupled to the rocking cam (24) in order to cause the rocking cam (24) to pivot about the fixed pivot axis with rotation of the camshaft. The rocker (26) is pivotable about a second axis that is movable relative to the fixed pivot axis of the rocking cam (24) in such a manner as to allow the valve lift, phase and duration of the valve event to be varied in dependence upon the position of the pivot axis of the rocker (26).

Abstract: A phase change coupling is disclosed for allowing the angular position of a drive member 10 of a camshaft 12 to be varied in relation to the camshaft. The coupling is additionally provided with a locking mechanism for preventing rotation of the drive member relative to the camshaft in only one direction during cranking of the engine, so that, during cranking of the engine, the drive member 10 is rotated in only one sense relative to the camshaft by the camshaft torque reversals until it reaches a predetermined start-up angular position.

Abstract: In a phase change mechanism in which the phase of a driven member (10) relative to a drive member (12) is adjusted by axial displacement of an actuating rod (30) connected to the piston (50) of a hydraulic jack rotatable with the drive and driven members, the cylinder (52) of the hydraulic jack has a double-skinned wall, and the gap (54) between the two skins of the cylinder wall serves as a passage for supplying oil to and from one of the working chambers of the hydraulic jack.

Abstract: A variable phase coupling for connecting a crankshaft to a camshaft comprises a drive member for connection to the crankshaft having helical grooves of a first pitch, a driven member for connection to the engine camshaft having helical grooves of a different pitch facing towards the grooves in the drive member, an intermediate member disposed between the drive and driven members having helical grooves on its inner and outer surfaces, a first set of balls engaging in the pairs of helical grooves comprising the helical grooves in the driven member and the facing grooves on one surface of the intermediate member, a second set of balls engaging in the pairs of helical grooves that comprise the grooves in the drive member and the facing grooves on the other surface of the intermediate member, and means for axially displacing the intermediate member relative to the drive and driven members.

Abstract: An internal combustion engine is described having a crankshaft (14) and a camshaft, the ends of which project from a front end of the engine. A hydraulically operable variable valve actuation mechanism is mounted on the camshaft at the front end of the engine for driving the camshaft. A front cover (10) that overlies the end of the camshaft projecting from the front end of the engine, includes passages (40, 42) that are connected to supply oil under pressure from an engine driven pump (16) to the variable valve actuation mechanism.

Abstract: A variable phase coupling for connecting a crankshaft to a camshaft (12) comprises a drive member (20) for connection to the crankshaft having grooves (40) of a first pitch, a driven member (14) for connection to the engine camshaft (12) having helical grooves (26) of a different pitch facing towards the grooves (40) in the drive member (20), balls (28) engaged in the two helical grooves (26, 40) and serving to couple the drive and driven members for rotation with one another, an intermediate member (16) disposed between the drive and driven members for rotation with one another, an intermediate member (16) disposed between the drive and driven members in contact with the balls (28, 34), and means (56) for displacing the intermediate member (16) relative to the drive and driven members. The displacement of the intermediate member (16) serves to move the balls relative to the helical grooves in the drive and driven members so as to vary the phase between the drive and driven members.

Abstract: A method is described for manufacturing a multi-component camshaft assembly having an internal mechanism for enabling relative angular movement of individual cams of the assembly. In the invention, the cam surfaces are machined after the individual components of the camshaft assembly have been assembled to one another.

Abstract: A valve operating mechanism comprises a hollow shaft (10), a sleeve journalled on the hollow shaft and having a cam, a coupling yoke (16) connected by a first pivot pin (18) to the hollow shaft (10) and by a second pivot pin (20) to the sleeve and means for pivoting the yoke (16) to effect a phase change between the hollow shaft (10) and the sleeve, wherein the means for pivoting the yoke (16) comprises an actuating rod (24) slidably received in the hollow shaft (10), a cam surface on the actuating rod (24) and a plunger (22) passing through a generally radial bore in the hollow shaft (10) to cause the yoke (16) to pivot in response to axial movement of the actuating rod (24).