Abstract: A summation rocker system is disclosed for acting on the end of a stem of a poppet valve (16) in dependence upon the combined lifts of a first and a second cam profile defined by different cam lobes (14, 22) of a concentric camshaft (46). The system comprises a first rocker (12) mounted on a pivot shaft (18) and having a first follower (44) to contact the first cam profile and an end acting on the valve (16) to displace the valve (16) by an amount dependent upon the lift of the first cam profile, a rocker shaft (24) to be fixedly mounted on the engine, and a second rocker (20) pivotable about the rocker shaft (24), the second rocker (20) having a second follower (48) to contact the second cam profile and acting to displace the pivot shaft (18) of the first rocker (12) in dependence of the lift of second cam profile.

Abstract: A hybrid dual phaser assembly is disclosed for mounting to an engine camshaft to allow the timing of two sets of cam lobes to be phased independently of one another relative to a crankshaft of the engine. The phaser assembly comprises an electrically operated phaser having intermeshing gears for transmitting torque to the camshaft and a phase control input driven by an electric motor to be mounted coaxially with the camshaft, and a hydraulically operated phaser having vanes movable within arcuate cavities. The cavities of the hydraulically operated phaser are defined in part by an annular member that radially surrounds, and axially overlaps, a gear of the electrically operated phaser, which gear is separate from the annular member and forms radially inner boundary walls of the cavities.

Abstract: A hybrid dual phaser assembly is disclosed for mounting to an engine camshaft to allow the timing of two sets of cam lobes to be phased independently of one another relative to a crankshaft of the engine. The phaser assembly comprises an electrically operated phaser having intermeshing gears for transmitting torque to the camshaft and a phase control input driven by an electric motor to be mounted coaxially with the camshaft, and a hydraulically operated phaser having vanes movable within arcuate cavities. The cavities of the hydraulically operated phaser are defined in part by an annular member that radially surrounds, and axially overlaps, a gear of the electrically operated phaser, which gear is separate from the annular member and forms radially inner boundary walls of the cavities.

Abstract: A summation rocker system is disclosed for acting on the end of a stem of a poppet valve (16) in dependence upon the combined lifts of a first and a second cam profile defined by different cam lobes (14, 22) of a concentric camshaft (46). The system comprises a first rocker (12) mounted on a pivot shaft (18) and having a first follower (44) to contact the first cam profile and an end acting on the valve (16) to displace the valve (16) by an amount dependent upon the lift of the first cam profile, a rocker shaft (24) to be fixedly mounted on the engine, and a second rocker (20) pivotable about the rocker shaft (24), the second rocker (20) having a second follower (48) to contact the second cam profile and acting to displace the pivot shaft (18) of the first rocker (12) in dependence of the lift of second cam profile.

Abstract: A valve system for an engine includes two cams each having a follower, a summation lever coupled to the followers, a lash adjuster, a valve actuating rocker pivotably coupled to the summation lever and resting on the lash adjuster, a control spring urging the summation lever to compress the lash adjuster, a stop limiting an expansion of the control spring, a bore, a plunger which moves in the bore, and an abutment surface. The control spring acts on the summation lever via the plunger. A plunger end engages with the summation lever. A point of contact between the plunger and the summation lever is displaced in a direction transverse to a plunger axis during a pivoting movement of the summation lever. A plunger shoulder is arranged a distance from the plunger end to contact the abutment surface to limit a plunger displacement in a direction compressing the lash adjuster.

Abstract: A valve system for an engine includes two cams each having a follower, a summation lever coupled to the followers, a lash adjuster, a valve actuating rocker pivotably coupled to the summation lever and resting on the lash adjuster, a control spring urging the summation lever to compress the lash adjuster, a stop limiting an expansion of the control spring, a bore, a plunger which moves in the bore, and an abutment surface. The control spring acts on the summation lever via the plunger. A plunger end engages with the summation lever. A point of contact between the plunger and the summation lever is displaced in a direction transverse to a plunger axis during a pivoting movement of the summation lever. A plunger shoulder is arranged a distance from the plunger end to contact the abutment surface to limit a plunger displacement in a direction compressing the lash adjuster.

Abstract: A camshaft assembly is disclosed that 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 is fast in rotation with the outer tube and the second group is rotatably mounted on the outer surface of the outer tube and is connected for rotation with the inner shaft. A timing wheel is connected for rotation with the inner shaft to provide position information to a sensor, the timing wheel being formed as a separate part that is assembled to one of the cam lobes in the second group.

Abstract: A variable valve actuating mechanism comprising a camshaft having two concentric cam lobes that may be rotated relative to one another a summation lever engaging with both cam lobes, a valve actuating rocker pivotally connected to the summation lever and engaging with a hydraulic lash adjuster at a first end and with a valve at a second end, and a shim surface movable with the pivot axis connecting the summation lever to the valve actuating rocker for limiting the expansion of the hydraulic lash adjuster to control clearance in the rocker system, wherein, in order to reduce friction, the shim surface abuts with a stationary stop surface that forms part of a camshaft support bearing.

Abstract: A rocker system comprising a summation lever and at least one valve actuating lever for use in a valve train of the type having two cams, a summation lever having followers engaging with both cams and a valve actuating lever pivotally connected to the summation lever for opening and closing an engine valve in dependence upon the sum of the lifts of the two cams, characterised in that the summation lever is assembled from opposed face plates and a separately formed hub.

Abstract: A variable valve actuating mechanism comprising a camshaft having two concentric cam lobes that may be rotated relative to one another a summation lever engaging with both cam lobes, a valve actuating rocker pivotally connected to the summation lever and engaging with a hydraulic lash adjuster at a first end and with a valve at a second end, and a shim surface movable with the pivot axis connecting the summation lever to the valve actuating rocker for limiting the expansion of the hydraulic lash adjuster to control clearance in the rocker system, wherein, in order to reduce friction, the shim surface abuts with a stationary stop surface that forms part of a camshaft support bearing.

Abstract: A concentric camshaft arrangement comprises an inner shaft, an outer tube concentrically arranged around the inner shaft and rotatably supported in a cylinder head. A first set of lobes is fixed for rotation with the outer tube and a second set of lobes is rotatably supported by bearing journals on the outer tube and connected for rotation with the inner shaft. The outer tube is supported in the cylinder head by means of a roller bearing and an oil feed is provided for supplying oil for lubricating the bearing journals of the second set of cam lobes. At least part of the oil feed is defined by a radial clearance between the outer surface and an inner surface of the cylinder head that is sealed at its axial ends, the radial clearance being larger than any radial clearance at the roller bearing so that loads on the camshaft are supported at least predominantly by the roller bearing.

Abstract: A spool valve for controlling a twin phaser for coupling a drive member to two driven members and to enable the phase of the two driven members to be varied independently includes a bore operably associated with the twin phaser, fluid channels opening into the bore, and a spool. The spool is received in and is moveable relative to the bore so as to selectively open and close the fluid channels in a predetermined manner, thereby providing a fluid communication between the spool and the twin phaser, and varying a phase of output members relative to an input member. The spool and the fluid channels are configured so that an axial displacement of the spool relative to the bore serves to control a phase of a first output member, and a rotation of the spool relative to the bore serves to control a phase of a second output member.

Abstract: An assembly is disclosed which comprises an SCP camshaft 130 and a phaser mounted at one end of the SCP camshaft. The phaser has a stator 112 driven by an engine crankshaft and two output members 114, 116 each fast in rotation with a respective one of the inner shaft 140 and the outer tube 126 of the SCP camshaft 130. Two timing features 160, 172 are provided for enabling respective sensors to determine the angular positions of the inner shaft and the outer tube of the SCP camshaft. In the invention, both timing features 160, 172 are located on the side of the stator 112 remote from the camshaft 130.

Abstract: An engine valve system comprises two cams (10,12) mounted coaxially, a summation rocker (14) coupled to followers (16,18) of both cams and movable in proportion to the instantaneous sum of the lifts of the respective cams, and a valve actuating rocker (20) pivotably coupled to the summation rocker (14) and operative to open an engine valve (22) in dependence upon the movement of the summation rocker (14). In the invention, the actuating rocker (20) rests on a hydraulic lash adjuster (24). A control spring (136) is provided to urge the summation rocker (14) in a direction to compress the hydraulic lash adjuster (24). A stop (138) associated with the control spring (136) limits the movement of the summation rocker (14) towards the lash adjuster (24) so as to set the clearance in the valve system when the valve (22) is closed and the cam followers (16,18) are on the base circles of the two cams (10,12).

Abstract: A valve mechanism is disclosed for a cylinder of an internal combustion engine which comprises two gas exchange poppet valves mounted in a cylinder head, a bridge 122 acting on the two valves, a cam for actuating the two valves, a slider 124 movable by the cam and slidable relative to the bridge 122, and a hydraulically controlled locking system having a latched position in which the slider transmits the force of the cam to the bridge 122 to actuate the two valves and a released position in which the valves are deactivated and the slider slides freely relative to the bridge. In the invention, the slider 124 is urged towards the cam by a spring 134 acting between the slider 124 and the cylinder head.

Abstract: A spool valve for controlling a twin phaser for coupling a drive member to two driven members and to enable the phase of the two driven members to be varied independently includes a bore operably associated with the twin phaser, fluid channels opening into the bore, and a spool. The spool is received in and is moveable relative to the bore so as to selectively open and close the fluid channels in a predetermined manner, thereby providing a fluid communication between the spool and the twin phaser, and varying a phase of output members relative to an input member. The spool and the fluid channels are configured so that an axial displacement of the spool relative to the bore serves to control a phase of a first output member, and a rotation of the spool relative to the bore serves to control a phase of a second output member.

Abstract: A method is disclosed for assembling a valve operating system for opening and closing a poppet valve mounted on an engine cylinder head. The valve operating system comprises a camshaft 18 having two coaxial cams 14 and 16 for operating the valve 12, a summation lever 20 coupled to followers 24,26 of the two cams 14 and 16, a control spring 40 acting on the summation lever 20 to urge one of the cam followers 26 into contact with the associated cam 16, and a valve actuating rocker 30 pivotably connected to the summation lever 20 and acting on the valve 12 to open and close the valve in dependence upon the sum of the instantaneous lifts of the two cams 14 and 16.

Abstract: A valve mechanism is disclosed for a cylinder of an internal combustion engine which comprises two gas exchange poppet valves mounted in a cylinder head, a bridge 122 acting on the two valves, a cam for actuating the two valves, a slider 124 movable by the cam and slidable relative to the bridge 122, and a hydraulically controlled locking system having a latched position in which the slider transmits the force of the cam to the bridge 122 to actuate the two valves and a released position in which the valves are deactivated and the slider slides freely relative to the bridge. In the invention, the slider 124 is urged towards the cam by a spring 134 acting between the slider 124 and the cylinder head.

Abstract: A method is disclosed for assembling a valve operating system for opening and closing a poppet valve mounted on an engine cylinder head. The valve operating system comprises a camshaft 18 having two coaxial cams 14 and 16 for operating the valve 12, a summation lever 20 coupled to followers 24,26 of the two cams 14 and 16, a control spring 40 acting on the summation lever 20 to urge one of the cam followers 26 into contact with the associated cam 16, and a valve actuating rocker 30 pivotably connected to the summation lever 20 and acting on the valve 12 to open and close the valve in dependence upon the sum of the instantaneous lifts of the two cams 14 and 16.

Abstract: An internal combustion engine is described having a valve mechanism that comprises two cams 120,122 mounted coaxially and a summation lever 124 having cam followers 126, 127 in contact with both cams so as to move in proportion to the instantaneous sum of the lifts of the respective cams. A control spring 128 is provided to maintain contact between one cam profile and its respective follower(s), and a valve actuating rocker 114 having a stationary pivot and rotatably connected to the summation lever serves to open the engine valve 110 in dependence upon the movement of the summation lever, so as to enable the valve timing, valve lift and valve event duration to be adjusted by varying the phases of the two cams.