Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
  • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
  • F01L1/34—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift
  • F01L1/344—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
  • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
  • F01L1/02—Valve drive
  • F01L1/04—Valve drive by means of cams, camshafts, cam discs, eccentrics or the like
  • F01L1/047—Camshafts
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
  • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
  • F01L1/34—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift
  • F01L1/344—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear
  • F01L1/3442—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear using hydraulic chambers with variable volume to transmit the rotating force
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
  • F01L13/00—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations
  • F01L13/0015—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque
  • F01L13/0057—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque by splittable or deformable cams
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
  • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
  • F01L1/02—Valve drive
  • F01L1/04—Valve drive by means of cams, camshafts, cam discs, eccentrics or the like
  • F01L1/047—Camshafts
  • F01L2001/0471—Assembled camshafts
  • F01L2001/0473—Composite camshafts, e.g. with cams or cam sleeve being able to move relative to the inner camshaft or a cam adjusting rod
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
  • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
  • F01L1/34—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift
  • F01L1/344—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear
  • F01L2001/34486—Location and number of the means for changing the angular relationship
  • F01L2001/34489—Two phasers on one camshaft
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
  • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
  • F01L1/34—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift
  • F01L1/344—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear
  • F01L2001/34486—Location and number of the means for changing the angular relationship
  • F01L2001/34493—Dual independent phasing system [DIPS]
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
  • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
  • F01L1/34—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift
  • F01L1/344—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear
  • F01L2001/34486—Location and number of the means for changing the angular relationship
  • F01L2001/34496—Two phasers on different camshafts

Definitions

• the invention relates to a phaser assembly for an internal combustion engine for changing the timing of two sets of cam lobes in relation to the engine crankshaft.
• Hybrid cars are becoming more commonplace, in which an electric motor is used in conjunction with an IC engine, and an increasing number of vehicles incorporate an automatic stop/start function for reducing engine fuel consumption.
• the ability to achieve a 'hot' restart with a minimum of noise and vibration is therefore becoming an increasingly important requirement. This is particularly true for diesel engines, which typically use significantly higher
• the opening duration of the intake and exhaust valve events can have a significant effect upon engine performance.
• the closing timing of the intake valves can be used to control the air mass trapped in the cylinder and the effective compression ratio, while the exhaust valve opening timing can be used to control the expansion ratio.
• Many systems have been proposed for controlling the opening duration of an engine valve, such as that shown in US 5,787,849 (esp. Fig.15), which superimposes a cyclic angular velocity variation onto the cam lobe rotation. The problem with systems of this type is that they add significant complexity and therefore cost to the engine valve train system.
• the invention seeks to provide a phaser assembly for use in an engine, the phaser assembly enabling improved fuel economy and emissions and allowing hot restart and shut-off operations to be carried out with reduced levels of
• phaser assembly for mounting on one end of a camshaft of an engine, the engine having two groups of cam lobes that are capable of being varied in phase relative to one another and relative to a crankshaft of the engine, the phaser assembly comprising two phasers each having an input member and at least one output member, wherein the first phaser of the assembly has an input member adapted to be driven directly by the engine crankshaft and an output member connectible to a first of the two groups of cam lobes, and the second phaser has an input member connected to, or formed
• phaser assembly comprises two separately controllable phasers acting on two groups of cam lobes.
• the first phaser acts to vary the phase of both groups of cam lobes relative to the engine crankshaft without varying the relative phase between the two groups and the second phaser acts to vary the phase of the second group relative to the first group and the engine crankshaft.
• the invention in this way provides within a single unitary phaser assembly, designed to be mounted on the end of an engine camshaft, two series connected phasers, in which the first phaser drives both second phaser and one of the two groups of cam lobes while the second phaser drives the second group of cam lobes.
• the phasers are preferably hydraulically operated vane- type phasers.
• a vane-type phaser is one having a rotor with radial vanes that divide arcuate recesses in a stator into circumferentially opposed hydraulic working chambers. As oil is pumped into one of the chambers and drawn from the other, the vanes move circumferentially to change the phase of the rotor relative to the stator.
• stator is used only to refer to the member defining the arcuate recesses and gives no indication of whether the member in question acts as the input or the output member of the phaser.
• the phasers may be arranged axially in line with one another while in other embodiments they may be arranged in the same axial plane but one radially within the other.
• the preferred configuration will be determined for any engine by the space available within the engine compartment.
• the cam lobes can be arranged on two separate solid camshafts, as can be found in DOHC engines with dual overhead camshafts, or they may be formed by the lobes of a concentric assembled camshaft, sometimes referred to as an SCP (single cam phaser) camshaft.
• Such an SCP camshaft comprises an inner shaft rotatably mounted within an outer tube. A first of the two groups of lobes is fast in rotation with the outer tube while the other group is free to rotate relative to the outer tube but is connected for rotation with the inner shaft by means of pins that pass with
• the invention is applicable to different engine
• lobes of the two groups can act on valves of the same type (intake or exhaust) while other lobes in the same group could act on valves of a different type.
• these lobes are phased relative to one another, it has the effect of increasing the duration of the valve event for that particular group.
• Improvements in engine fuel economy performance can then be gained from optimising the valve lift event duration over the full engine operating range.
• Valve trains are also known where the cam follower is a switching cam follower, where the follower is able to switch between two sets of cam lobe profiles on the same camshaft.
• a follower is outlined in EP0620360 and US6668779. It is also possible to use the invention in an engine that uses such a switching follower system, where further benefits in performance could be obtained.
• Valve trains are also known in which two cam lobes act on the same valve through a summation lever to enable the valve lift and/or duration to be varied by appropriately setting the relative phase of the two cam lobes.
• Camshafts for such valve trains are termed variable lift and duration camshafts and will be referred to below by the acronym VLD. These camshafts also have two groups of cam lobes that are phased relative to one another to effect a change in the resulting valve lift event.
• Figs. IA to IE show different valve train
• Fig. 2A is a perspective view of a first embodiment of a dual phase assembly of the present invention mounted on one end of a concentric camshaft,
• Fig. 2B is a side view of the assembly in Fig. 2A
• Fig. 2C is a section taken through the axial plane C-C in Fig. 2B
• Fig. 3 is a view similar to than of Fig. 2C showing a section through a second embodiment of the invention
• Fig. 4A is a side view of a third embodiment of the invention.
• Figs. 4B and 4C are sections taken through the axial planes B-B and C-C in Fig. 4A, respectively,
• Fig. 5A is a perspective view of a fourth embodiment of the invention.
• Fig. 5B is a side view of the embodiment of Fig. 5A
• Figs. 5C and 5D are sections taken through the axial planes C-C and D-D in Fig. 5B, respectively
• Fig. 5E is an axial section taken through the plane E-E in Fig. 5C.
• Fig. IA shows a valve train configuration in which the first and second lobe groups are formed on two solid camshafts.
• the group of cam lobes may operate the intake valves and the second group the exhaust valves of an engine.
• a twin phaser driving two cams is known, for example from Figures 9 and 10 of EP1234954.
• Fig. IB shows a valve train configuration having a phaser assembly of the invention mounted on a concentric camshaft.
• This camshaft and phaser configuration would suit DOHC engines as well as three-valve per cylinder engines.
• both lobe groups operate on the same type of valve (intake or exhaust) , with the first lobe group controlling the first of a pair of identical valves within each cylinder and the second the other.
• the resulting system therefore makes whole camshaft phasing as well as adjacent lobe phasing possible.
• valve train configuration of Figure 1C is generally similar to that of Fig IB save that it uses a VLD camshaft, as described for example in EP 1417399. In this
• Fig. ID shows a configuration having two lobe groups on separate camshafts, one concentric and the other solid.
• Fig. IE The configuration shown in Fig. IE is similar to that of Figure ID and is suitable for DOHC engines, where the four valve pattern is rotated through 90°, so the lobes operating each pair of intake/exhaust valves are located on different camshafts.
• Fig. ID and Fig. IE can be modified to incorporate VLD camshafts .
• FIG. 1 shows different embodiments of a dual phaser assembly of the present invention, which is represented schematically in each of Figs. IA to IE by the box in-between the crankshaft drive and the camshaft (s) .
• the dual phaser assembly in each case comprises two separately controllable phasers arranged to act in series such that the first phaser changes the phase of both of two lobe groups relative to the engine crankshaft while the second changes the phase of the two lobe groups relative to one another.
• Figs. 2A and 2B shows a dual phaser assembly 100 mounted on one end of a concentric camshaft 102 having an inner shaft driving one of the two groups of lobes and an outer tube driving the other group of lobes.
• the phaser assembly 100 is hydraulically operated and controlled by oil fed into it by a supply spigot 104 that is stationary and mounted, for example, on an engine cover.
• the internal design of the phaser assembly 100 is such that one pair of control lines change the phase of the entire camshaft 102 relative to the crankshaft while a second pair of control lines rotate the inner shaft of the concentric camshaft relative to its outer tube.
• vane-type phasers As the construction of vane-type phasers is well known and documented, the following description will not include a detailed explanation of the construction of the vanes nor of the manner in which control oil is channelled from the supply spigot 104 to the individual working chambers of the phasers .
• the two phasers in Fig. 2C share a common stator 114 that defines six circumferentially spaced recesses.
• the other three of the recesses, designated 116b, form the working chambers of a second phaser of which the rotor 118 is a central hub carrying radially outwards projecting vanes.
• the rotor 112 serves as the input member of the first phaser and the stator 114 as its output member.
• the stator 114 doubles as the input member of the second phaser and is directly coupled to the outer tube of the concentric
• the rotor 118 of the second phaser is coupled to the inner shaft of the concentric camshaft 102.
• the stator 114 rotates relative to the sprocket 110. If at the same time no oil is transferred between the working chambers in the recesses 116b the stator 114 and the rotor 118 of the second phaser will be locked relative to one another. Therefore both the inner shaft as well as the outer tube of the concentric camshaft will be rotated relative to the crankshaft.
• Controlling the oil supply to the chambers in the recesses 116b on the other hand will not affect the phase of the stator 114 and the outer tube of the camshaft 102 and will only change the phase of the inner shaft relative to both the outer tube and the engine crankshaft.
• Fig. 2C also shows one of two hydraulically operated locks 120 and 122, which are also known and need not be described here in detail.
• the locks are used to dictated the positions of the phaser during starting when the
• the lock 120 locates the rotor 112 relative the stator 114 while the lock 122 locates the stator 114 relative to the rotor 118. Similar locks are present in all the illustrated embodiments of the invention.
• Fig.3 shows an alternative embodiment in which one phaser is contained radially within the other.
• This construction offers the advantage that each phaser has six working chambers rather than three, allowing the torque to be spread over a larger number of vanes.
• the stator 212 of the first phaser is connected to the drive sprocket 210.
• the rotor 214 of the first phaser is connected to the outer tube of the camshaft and doubles as the stator of the second phaser.
• the rotor 218 of the second phaser is once again constructed as a central hub connected to the inner shaft of the camshaft.
• the third embodiment differs from the embodiments of Figures 2 and 3 in that the two phasers are axially spaced instead of being radially spaced, stator 312 of the first phaser is formed integrally with the drive sprocket 310.
• the rotor 314A of the first phaser is coupled to the outer shaft of the concentric camshaft and is directly connected to the stator 314B of the second phaser.
• the rotor 318 of the second phaser is coupled to the inner shaft of the concentric camshaft.
• Figures 5A to 5E shows an alternate design in which the vanes are axially clamped in position.
• the dual phaser assembly 500 is mounted on the end of a
• concentric camshaft 502 and containes two phasers.
• the two phasers are axially spaced from one another, one lying in the plane C-C of Fig. 5B and shown in the section of Fig. 5C and the other lying in the plane D-D and shown in Fig. 5D.
• the two sets of vanes 530 and 532 are axially clamped to a thin plate 534 which doubles as the rotor of the two phasers.
• the vanes 530 are clamped by bolts 536 to the rear plate 538 of the phaser assembly 500, which is in turn secured by means of bolts to the outer tube 502A of the concentric camshaft 502.
• the front plate 540 of the phaser assembly is secured by means bolts 539 to the vanes 530, the bolts passing through aligned but unthreaded holes in the vanes 532.
• the stator 512 of the first phaser is thus formed by sprocket wheel 510 and serves as the input member of the first phaser.
• the rotor of the first phaser is formed by the vanes 530 which are coupled to the outer tube 502a of the concentric camshaft 502 through the back bolts 536 and the rear plate 538. This serves as the output member of the first phaser.
• the rotor of the second phaser is formed by the vanes 532 and front plate 540 which are coupled to the output of the first phaser via front bolts 539. This serves as the input member of the second phaser.
• the plate 534 acts as both the rotor and output member of the first phaser and the rotor and input member of the second phaser, of which the stator 542 is coupled to the inner shaft 502b by the hub 544 on which the stator 542 is a driving fit.
• timing markers 550 and 552 can be formed on the front plate 540 and on the circumference of the stator 542 of the second phaser so that the phase of both groups of lobes can be measured at all times from in front of the cam drive

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Valve Device For Special Equipments (AREA)
• Valve-Gear Or Valve Arrangements (AREA)

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Publications (1)

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Cited By (3)

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Citations (17)

Family Cites Families (5)

• 2009
  • 2009-07-23 GB GB0912789.5A patent/GB2472054B/en active Active
• 2010
  • 2010-07-09 WO PCT/IB2010/053162 patent/WO2011010241A1/en active Application Filing
  • 2010-07-09 EP EP10742896.3A patent/EP2456961B1/en active Active
  • 2010-07-09 CN CN201080032890.4A patent/CN102439265B/zh active Active

Patent Citations (17)

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