EP1266130A1 - Mecanisme de commande de soupape - Google Patents

Mecanisme de commande de soupape

Info

Publication number
EP1266130A1
EP1266130A1 EP01912014A EP01912014A EP1266130A1 EP 1266130 A1 EP1266130 A1 EP 1266130A1 EP 01912014 A EP01912014 A EP 01912014A EP 01912014 A EP01912014 A EP 01912014A EP 1266130 A1 EP1266130 A1 EP 1266130A1
Authority
EP
European Patent Office
Prior art keywords
camshaft
engine
cam
piston
spline
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP01912014A
Other languages
German (de)
English (en)
Inventor
Christopher Paulet Melmoth Walters
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Publication of EP1266130A1 publication Critical patent/EP1266130A1/fr
Withdrawn legal-status Critical Current

Links

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
    • 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
    • F01L13/0036—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 the valves being driven by two or more cams with different shape, size or timing or a single cam profiled in axial and radial direction
    • F01L13/0042—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 the valves being driven by two or more cams with different shape, size or timing or a single cam profiled in axial and radial direction with cams being profiled in axial and radial direction

Definitions

  • This invention relates to a valve control mechanism for an internal combustion engine, to engines containing such mechanisms and to a method of operating the valves of an internal combustion engine.
  • valve control mechanism which comprises: a camshaft carrying a plurality of cams, the camshaft being mounted in a cam carrier and being arranged for a limited degree of axial movement and having associated with it means for effecting such movement, each of the cam surfaces having an outline, in a section plane containing the axis of the camshaft, which is not parallel to that axis, whereby in use the valve action is a function of the axial location of the camshaft within the range of permitted axial movement, the mechanism also comprising a cam follower for each cam, the cam follower comprising a one-piece body which reciprocates within a slideway and at one extremity acts upon the end of a valve stem through only a shim and has at the opposite extremity a trough of part- circular cross-section which receives a member in the form of a segment of a circular cylinder, the curved surface of which faces the interior surface of the trough, so that said member can turn with respect
  • the present invention offers developments derived from this earlier valve control mechanism.
  • Our British Patent Application No. 9925628.1 (filed 29 October 1999 and to be published as GB 2 341 659A on 22 March 2000), and our International Patent Application No. PCT/GB99/03412 filed 15 October 1999, describe and claim several improvements in a valve control system of the type disclosed in GB 2 190 140B.
  • one embodiment of the said British and International Patent Applications relates to a valve control mechanism which comprises: a camshaft carrying a plurality of cams, the camshaft being mounted in, or being adapted to be mounted in, a cylinder head or cam carrier, the valve control mechanism further including means for relatively advancing and retarding the rotation of the camshaft, said advance/retard means comprising a piston housed and axially displaceable within a cylinder, the axial position of said piston being under hydraulic control, and a mechanical coupling between said piston and the camshaft, said mechanical coupling serving to translate the axial movement of said piston into... relative rotational movement of said camshaft.
  • the piston and cylinder may be housed within a camshaft pulley at the front end of the camshaft.
  • the cylinder is defined, at its front end, by a front plate having an annular flange extending towards the camshaft; and at its rear end by the front face of a housing within which said mechanical coupling is housed.
  • the mechanical coupling between the piston and the camshaft comprises a spline mechanism acting between said piston and the front end of said camshaft.
  • a spline mechanism may be mounted within a housing, the front end surface of said housing forming the rear wall of said cylinder, as indicated above.
  • a first channel is provided to deliver hydraulic fluid to the interior of said cylinder directly behind said front plate, and a second channel is provided to deliver hydraulic fluid to said cylinder directly in front of the housing for said mechanical coupling.
  • the pistoi is arranged so that its own axial displacement results additionally in axial displacement of the camshaft.
  • each cam has associated therewith a cam follower comprising a body which reciprocates within a slideway and at one extremity acts upon the end of a valve stem, the cam follower having at its opposite extremity a trough of curved cross-section which receives a member in the form of a segment having on one side thereof a surface curved correspondingly to that of said trough, and having on the other side thereof a planar surface, whereby the curved surface of the segment enables said member to turn with respect to said body, while the planar surface of the member cooperates with the cam surface.
  • the cam followers are preferably disposed relative to the valve stems such that the zone of action between the each cam follower and the end of its respective valve stem is located away from the midpoint (measured in a direction parallel to the axis of the camshaft) of a section through the cam follower in a plane which contains the axis of the camshaft and the axis of the valve stem.
  • a particularly preferred arrangement disclosed therein is where said end of the valve stem is partly recessed within the body of the cam follower.
  • valve control mechanism which comprises: a camshaft carrying a plurality of cams, the camshaft being mounted in a cylinder head or cam carrier and being arranged for a limited degree of axial movement and having associated with it means for effecting such movement, each of the cam surfaces having an outline in section taken through a plane containing the axis of the camshaft which is not parallel to that axis, whereby in use the valve action is a function of the axial location of the camshaft within the range of permitted axial movement; and a cam follower for each cam, the cam follower comprising a body which reciprocates within a slideway and at one extremity acts upon the end of a valve stem, the cam follower having at its opposite extremity a trough of part-circular cross-section which receives a member in the form of a segment of a circular cylinder, the curved surface of which faces the interior surface of the
  • valve control mechanism may further comprise means for relatively advancing and retarding the rotation of the camshaft.
  • the mechanism may be arranged so that control of the axial displacement of the camshaft acts also to control the relative rotational adjustment of the camshaft. This provides good control of valve action and can be implemented relatively easily.
  • control of the axial displacement of the camshaft acts independently of the relative rotational adjustment of the camshaft. This permits greater freedom to influence valve action, but requires more control functions within or associated with the engine.
  • the present invention is concerned with a valve control mechanism of the type permitting independent control of the "axial" camshaft adjustment and of the "rotational" camshaft adjustment. This permits controlled variation or adjustment of valve lift, duration and timing; thus the control mechanism is termed “WLDT” - an acronym for "variable valve lift/duration/timing” .
  • an internal combustion engine including a camshaft carrying a plurality of cams, the camshaft being mounted in a cylinder head or cam carrier; and a valve control mechanism comprising: (a) first means for effecting a limited degree of axial movement of the camshaft; and (b) second means for varying the rotational phase of said camshaft, characterised in that said first and second means comprise a pair of concentric pistons housed within a cylinder and under independent control, whereby the concentric pistons can be moved independently of one another.
  • the outer piston serves to control the advance/retard function (i.e. the rotational phase adjustment of the camshaft); and the inner piston controls the axial adjustment of the camshaft.
  • valve timing is adjusted independently of the valve lift and duration when the cams are suitably profiled.
  • the position of said pistons is controlled hydraulically.
  • High pressure oil is the preferred hydraulic medium.
  • the camshaft moves axially along a straight spline in a drive chain sprocket sleeve under the action of said inner piston; the piston can be acted upon by high pressure oil on both sides thus effecting the valve lift & duration changes; concentric with the inner piston is an outer piston also acted upon by high pressure oil on both sides which moves the chain sprocket sleeve containing a straight spline on its inner diameter mounted on the camshaft and a helical spline on its outer diameter mounted in the chain sprocket thus effecting a rotation of the camshaft and thereby changing its timing.
  • said sprocket sleeve prefferably has a helical spline on its outer surface, the arrangement being such that movement of said outer piston causes the chain sprocket sleeve to move axially along the camshaft, thereby imparting a rotational movement to said camshaft through the action of said helical spline. In this way the rotational phase of the camshaft is adjusted, thus in use altering the valve timing of the engine.
  • the primary chain drive system in the present invention may be generally the same as that disclosed in our prior patent applications except for a new sprocket design which is preferably mounted on two angular contact ball bearings mounted on a large diameter bearing housing which is part of the new bearing carrier. These bearings are capable of taking radial, axial & tilting loads.
  • the second chain drive behind the forward primary drive sprocket is preferably replaced by repositioned helical gears which are part of the sprocket & located just behind the drive sprocket on the inlet side G. via a similar gear with no sprocket on the exhaust side whose mounting is offset rearwards.; the .camshafts thus contra-rotate.
  • Both pistons can be prevented from rotating - e.g. in the case of the inner piston by two radial thrust rollers; and by two angular contact ball bearings in the case of the outer piston.
  • the cam lobes are mounted on the camshaft in pairs.
  • the cam bearings are re- positioned on either side of the cam lobe pairs instead of between them as in the standard engine shown in our earlier patent applications mentioned above.
  • valve control device it is possible to package the valve control device in a compact form within an existing cylinder head/cover length and overall width for an existing engine installation in a car.
  • the new sprocket mounting and gear arrangement just described makes it possible to provide a drive train which is much stiffer than with conventional valve control mechanisms. Furthermore, the loads associated with this new sprocket mounting and gear arrangement are separated from the WLDT actuating device; and the internal space in the sprocket below the bearing mounting can be utilized to allow the compact installation of this combined device.
  • FIGURE 1 is a sectional view through part of an internal combustion engine in accordance with our earlier patent applications (GB9925628.1 and PCT/GB99/03412), with certain parts omitted for the sake of clarity;
  • FIGURE 2 shows a sectional view, taken in the plane containing the valve stems, through part of an internal combustion engine in accordance with the present invention, the concentric pistons of the WLDT device being at one extreme of their permitted movement;
  • FIGURE 3 shows a sectional view corresponding to that of Figure 2, but with the concentric pistons at the other extreme of their permitted movement;
  • FIGURE 4 shows a view from the front end of the engine (i.e. from the right as seen in Figs. 1 and 2 ) ; and
  • FIGURE 5 shows a horizontal sectional view through the engine of Figs. 2 and 3.
  • valve control mechanism comprises an overhead camshaft 4 which carries a plurality of profiled cams 5.
  • Each of the cams 5 cooperates with a half roller 16 which sits in a recess 19 formed on the upper surface of a rectangular cam follower body 6.
  • the half roller 16 is in the form of a segment of a circular cylinder and is free to rotate about its longitudinal axis while seated in the recess 19.
  • Valve stem 1 cooperates with cam follower body 6 and is held in place by retainers 2 (only the upper retainer is shown in Fig. 1) and compression springs 3.
  • the cam profiles are three dimensional, i.e. valve lift varies tangentially with ca angle_ in end view and varies along the camshaft linearly at each cam angle in side view. If desired, the profile of each cam may be such that a line connecting the points of maximum radial extent of the cam at opposite ends (in the direction of the camshaft axis) thereof is non-parallel to the axis of the camshaft.
  • Fig. 1 the front end of camshaft 4 is connected to a piston 7 located within a cylinder 9 through the intermediary of a spline 8.
  • the chamber of cylinder 9 is defined by a front plate 10 and by an annular flange 11 integral with plate 10; the rear face 12 of the chamber is part of a housing 13 which contains the spline 8.
  • the inner surface 14 of housing 13 is provided with a screw thread (not shown) which cooperates with spline 8 so that axial movement of the spline relative to the housing 13 causes rotation of the spline.
  • Housing 13 acts as a carrier for spline 8 and, through the action of bearing surface 40, constitutes an outer bearing for the front end of camshaft 4 within cylinder head or carrier 41.
  • An inner bearing for the front end of camshaft 4 is provided by the outer diameter of splines and the inner spline track diameter.
  • These two (outer and inner) bearings are supported on camshaft pulley bearings 39 via elements 13 and 11, and camshaft pulley 42.
  • the camshaft pulley bearings 39 can accept radial and axial loads and provide a stiffer than conventional "means of mounting the camshaft pulley on a circular ring 43 which forms part of the cylinder head structure together with parts 41 and 44.
  • axial movement of the piston 7 and spline 8 is caused by the supply of oil under pressure to chamber 9 _yia inlets 15 and 17; oil is supplied to these inlets from proportional programmable valves, e.g. "Moog" valves (not shown).
  • proportional programmable valves e.g. "Moog” valves (not shown).
  • piston 7 is caused to move axially within chamber 9, thereby moving spline 8 and camshaft 4 by a corresponding axial amount.
  • This movement causes an additional rotational movement of spline 8, thereby rotationally advancing or retarding the camshaft within pre-set limits (e.g. as defined by the number and disposition of the helical grooves 20-27 formed in cylinder 18 ) .
  • camshaft 4 The effect of axial movement of camshaft 4 will be discerned from Figure 1: movement to the left causes the valve stem 1 to rise relative to its previous position at the same point in its cycle, thus giving greater valve lift and, if desired, a change in camshaft duration.
  • the rotational advancement imparted by spline 8, 18 additionally advances the valve timing. Movement to the right reverses these effects.
  • the WLDT device in the present invention differs from that of Figure 1 in that the two functions - axial displacement of the camshaft and its relative rotation to provide an advance/retard effect - are independent of one another rather than linked.
  • the control mechanism comprises a pair of concentric pistons 101 and 102 disposed within a housing 100.
  • Figure 2 shows a side view of the cylinder head, cam carrier and camshaft 4 which moves axially along a straight spline in a drive chain sprocket sleeve via inner piston 102 acted upon by high pressure oil on both sides thus effecting the valve lift and duration changes.
  • an outer piston 102 Concentric with the inner piston is an outer piston 102 also acted upon by high pressure oil on both sides which moves chain sprocket sleeve 105 containing a straight spline 106 on its inner diameter mounted on the camshaft and a helical spline 107 on its outer diameter mounted in chain sprocket 108 thus effecting a rotation of the camshaft and changing its timing.
  • This view shows both pistons fully forward.
  • Figure 3 is the same view as Fig. 2 but with both pistons 101 and 102 fully rearwards.
  • the primary chain drive system is as standard except for the new sprocket (108) design which is mounted on two angular contact ball bearings 109 mounted on a large diameter bearing housing 110 which is part of the new bearing carrier - shown above the red split line in both Figs. 2 and 3. These bearings are capable of taking radial, axial and tilting loads.
  • the second chain drive behind the forward primary drive sprocket is replaced by repositioned helical gears which are part of the sprocket and located just behind the drive sprocket on the inlet side and via a similar gear with no sprocket on the exhaust side whose mounting is offset rearwards - see Figure 5.
  • the camshafts thus contra-rotate.
  • Both pistons 101 and 102 are prevented from rotating - in the case of the inner piston 102 this is achieved by two radial thrust rollers; and by two angular contact ball bearings 110 in the case of the outer piston.
  • Figs. 2-5 The arrangement of Figs. 2-5 makes it possible to package the WLDT device in a compact form within an existing cylinder head/cover length and overall width for an existing engine installation in a production car.

Landscapes

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

Abstract

On décrit un moteur à combustion interne. Le moteur comprend un arbre à cames qui comporte une pluralité de cames, l'arbre à cames étant monté dans une culasse ou un porte-cames ; et un mécanisme de commande de soupape qui comprend : (a) un premier dispositif qui autorise l'arbre à cames à effectuer un déplacement axial limité ; et (b) un deuxième dispositif qui permet de varier la phase de rotation de l'arbre à cames ; ce mécanisme se caractérisant en ce que les premier et deuxième dispositifs comprennent une paire de pistons concentriques logés dans un cylindre et sont soumis à une commande hydraulique indépendante, ceci permettant aux pistons concentriques de se déplacer indépendamment l'un de l'autre. Ce système permet de varier la levée, la durée et la synchronisation des soupapes lorsque l'arbre à cames comporte des bossages de cames à profil tridimensionnel (c'est-à-dire que la levée des soupapes varie tangentiellement à l'angle des cames dans une vue de face et varie linéairement le long de l'arbre à cames au niveau de chaque angle de came en vue latérale).
EP01912014A 2000-03-21 2001-03-21 Mecanisme de commande de soupape Withdrawn EP1266130A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
GBGB0006875.9A GB0006875D0 (en) 2000-03-21 2000-03-21 Valve control mechanism
GB0006875 2000-03-21
PCT/GB2001/001249 WO2001071167A1 (fr) 2000-03-21 2001-03-21 Mecanisme de commande de soupape

Publications (1)

Publication Number Publication Date
EP1266130A1 true EP1266130A1 (fr) 2002-12-18

Family

ID=9888144

Family Applications (1)

Application Number Title Priority Date Filing Date
EP01912014A Withdrawn EP1266130A1 (fr) 2000-03-21 2001-03-21 Mecanisme de commande de soupape

Country Status (6)

Country Link
US (1) US20030051687A1 (fr)
EP (1) EP1266130A1 (fr)
JP (1) JP2003528247A (fr)
AU (1) AU2001240932A1 (fr)
GB (1) GB0006875D0 (fr)
WO (1) WO2001071167A1 (fr)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ES2323400B1 (es) * 2007-08-08 2010-04-30 Antonio Ribas Bonet Arbol de levas.
DE102008029349A1 (de) * 2008-06-20 2009-12-24 Daimler Ag Ventiltriebvorrichtung
DE102008029325A1 (de) * 2008-06-20 2009-12-24 Daimler Ag Ventiltriebvorrichtung
EP2325444A4 (fr) * 2008-08-13 2012-01-11 Chery Automobile Co Ltd Arbre à cames hydraulique et son système de commande hydraulique
DE102009010407A1 (de) * 2009-02-26 2010-09-02 Schaeffler Technologies Gmbh & Co. Kg Ventiltrieb einer Brennkraftmaschine mit einer Verstelleinrichtung
US9360270B2 (en) 2013-08-21 2016-06-07 Raytheon Company Launcher with multi-part pusher, and method

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4708101A (en) * 1984-12-20 1987-11-24 Nissan Motor Co., Ltd. Driving apparatus for intake and exhaust valves of internal combustion engine
GB8610727D0 (en) 1986-05-01 1986-06-04 Walters Eng Consultant Ltd Chr Valve lift mechanism
US5143034A (en) * 1990-03-29 1992-09-01 Mazda Motor Corporation Lubrication system for V-type overhead camshaft engine
EP0590577A1 (fr) * 1992-09-30 1994-04-06 Mazda Motor Corporation Système de commande de variation de calage de soupape de moteur
JPH10317927A (ja) * 1997-05-15 1998-12-02 Toyota Motor Corp 内燃機関のバルブ特性制御装置
JPH11210433A (ja) * 1998-01-29 1999-08-03 Denso Corp 可変弁制御装置
DE69905924T2 (de) 1998-10-30 2004-01-15 Christopher Paulet Mel Walters Ventilsteuerungseinrichtung
JP2000170514A (ja) * 1998-12-09 2000-06-20 Denso Corp 可変弁制御装置
US6216654B1 (en) * 1999-08-27 2001-04-17 Daimlerchrysler Corporation Phase changing device

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO0171167A1 *

Also Published As

Publication number Publication date
GB0006875D0 (en) 2000-05-10
JP2003528247A (ja) 2003-09-24
US20030051687A1 (en) 2003-03-20
AU2001240932A1 (en) 2001-10-03
WO2001071167A1 (fr) 2001-09-27

Similar Documents

Publication Publication Date Title
US6474281B1 (en) Valve control mechanism
US5474038A (en) Device for continuous automatic angular adjustment between two shafts in driving relationship
US5669343A (en) Valve timing control system for internal combustion engine
US5031583A (en) Valve operating device for internal combustion engine
US5566651A (en) Device for continuous angular adjustment between two shafts in driving relationship
US5359970A (en) Valve drive for an internal combustion engine
US20010054403A1 (en) Valve moving apparatus of an internal combustion engine
US6745736B2 (en) Valve control mechanism
JPH02271009A (ja) 内燃機関においてクランク軸に対するカム軸の相対角度を調整する装置
US5431132A (en) Variable valve gear of internal combustion engines
EP0636768B1 (fr) Variateur automatique pour l'ajustement du calage de la distribution
EP0462568B1 (fr) Système de distribution, notamment pour un moteur à combustion interne avec un certain nombre de soupapes par cylindre
US4805567A (en) Valve mechanism for at least two simultaneously actuable valves
US5893345A (en) Valve control apparatus for an internal combustion engine
US5033327A (en) Camshaft phasing drive with wedge actuators
US20030051687A1 (en) Valve control mechanism
US5094197A (en) Timing system, particularly for an internal combustion engine with a number of valves per cyclinder
EP0816643B1 (fr) Actuateur hydraulique pour moteur à combustion interne
EP0791727B1 (fr) Arbre à cames de moteur entraíné par un dispositif de commande variable des soupapes
US6263845B1 (en) Phase change mechanism
GB2359608A (en) Valve control mechanism
JP2607763B2 (ja) シリンダに多数のバルブを具備した特に内燃機関用タイミング機構
GB2305707A (en) Cam arrangement for an internal combustion engine
GB2175365A (en) Arrangements for converting rotary motion to linear motion

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20021014

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR

AX Request for extension of the european patent

Free format text: AL;LT;LV;MK;RO;SI

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN

18W Application withdrawn

Effective date: 20031119