WO1987007677A1 - Actuateur variable pour une soupape - Google Patents

Actuateur variable pour une soupape Download PDF

Info

Publication number
WO1987007677A1
WO1987007677A1 PCT/GB1987/000411 GB8700411W WO8707677A1 WO 1987007677 A1 WO1987007677 A1 WO 1987007677A1 GB 8700411 W GB8700411 W GB 8700411W WO 8707677 A1 WO8707677 A1 WO 8707677A1
Authority
WO
WIPO (PCT)
Prior art keywords
valve
cam
chamber
actuator
piston
Prior art date
Application number
PCT/GB1987/000411
Other languages
English (en)
Inventor
Stephen John Charlton
David John Bell
Peter Charles Howard
Andrew John Haines
Stuart Lawrence Bird
Original Assignee
South Western Industrial Research Limited
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 South Western Industrial Research Limited filed Critical South Western Industrial Research Limited
Priority to DE8787903892T priority Critical patent/DE3770822D1/de
Publication of WO1987007677A1 publication Critical patent/WO1987007677A1/fr

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
    • 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
    • F01L13/0031—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 modification of tappet or pushrod length
    • 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
    • F01L1/12—Transmitting gear between valve drive and valve
    • F01L1/14—Tappets; Push rods
    • F01L1/16—Silencing impact; Reducing wear
    • 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
    • F01L9/00—Valve-gear or valve arrangements actuated non-mechanically
    • F01L9/10—Valve-gear or valve arrangements actuated non-mechanically by fluid means, e.g. hydraulic

Definitions

  • This invention relates to variable actuators for valves and in particular, but not exclusively, to such actuators for use with internal combustion engine valves. .
  • the valves are opened and closed by means of a
  • cam whose profile is fixed for all operational speeds, although the rate of opening and closing of the valves increases with engine speed as the rate of rotation of Q . the cam increases. It has been known for some time that the combustion efficiency and torque of an engine can be improvedby altering the open period of a valve and that the optimal open period differs with engine speed. Thus, current cam profiles represent a compromise and are 5 therefore unsatisfactory.
  • the invention consists in an actuator for a. valve comprising bias means for urging the valve into a closed position and means for opening the valve against the bias means including means for variably damping the closing of the valve by the bias means.
  • the opening means may include a cam and cam follower means for causing opening of the valve in response to movement of it by the cam in a first direction.
  • the damping means may act on at least part of the cam follower means to disconnect it, and hence the valve,operatively from the cam for a controllable period.
  • the cam follower means may comprise a hollow elongate body divided into first and second chambers by a generally central wall,an actuator piston for operating the valve disposed in the first chamber, a second cam-operated piston in the second chamber and means for interconnecting the first and second pistons so that the valve is opened by the first piston in response to cam induced movement of the second piston, the first chamber containing fluid which can be vented from the chamber through an outlet port in response to closing movement of the valve and the damping means may comprise a variable restriction in that outlet port.
  • the second chamber may also contain fluid, in which case the central wall may include a fluid flow BKCD/JC
  • the body may be provided with a fluid input and a fluid output such that the fluid in the cam follower means is changed in each cycle in response to one or both of the pistons.
  • the fluid inlet may be connected to the first chamber and the fluid outlet may be connected to the second chamber.
  • a further fluid input may be connected to the second chamber for supplying fluid under pressure to maintain the second piston in contact with the cam during the valve closing part of the cycle. in one arrangement the transfer of fluid via the fluid flow path imparts valve opening movement to the first piston in response to cam induced movement of the second piston.
  • support means may be mounted on the second piston for carrying the first piston during the valve opening part of the cycle, whilst allowing an independent movement of the pistons during the valve closing part of the cycle.
  • first and second pistons may be effectively integral one with the other. Where fluid inlets and outlets are not provided there may be a top-up port which can debouch into either chamber but preferably opens on the first chamber.
  • a bypass flow path may also be provided allowing flow from the first to the second chamber under certain operating conditions.
  • the invention consists in an actuator for a valve comprising bias means for urging the valve into a closed position, and means for opening the valve against the action of the bias means, the valve opening means including a cam, cam follower means for causing opening of the valve in response to movement of the cam in a first direction and control means for controlling the rate of return of the cam follower means in the reverse direction under action of the bias means, the arrangement being such that at least part of the cam follower means is operatively disconnectable from the cam for a controllable period.
  • the actuator is used to control the operation of one or more valves of an internal combustion engine, and is particularly suitable .for use with the inlet valves of such an engine.
  • the control means may be controlled in response to an operating parameter of the engine and preferably in accordance with a parameter which represents or reflects engine speed.
  • the control means may vary the rate of flow in accordance with the inlet manifold pressure, the oil pressure, or
  • valves may be controlled individually, or all the inlet valvesmay be controlled sim ⁇ ltaneously by a linking mechanism.
  • the control may be based on a mechanical or electrical system. If it is electrical the control may be .continuous and designed to maintain the valve operation in accordance with a pre-determined "optimum" performance.
  • the profile of the cam is . selected in accordance with the desired low speed (e.g. 1,000 r.p. . and under) performance of the engine and C that the ..outlet.. ' . ' por .- • - . is opened increasingly as engine speed increases.
  • the cylinder and other portions of the opening means may be formed in the engine casing.
  • Figure 1 is a partly schematic view of a valve train including the actuator of the invention
  • Figure 2 is a graph of the valve opening with respect to time
  • Figure 3 is a graph of the controlled opening area against engine speed and its variation with temperature
  • Figure 4 is a schematic view of a bypass
  • Figure 5 illustrates a dampening arrangement for use in the invention
  • Figure 6 is a schematic view of a centralised control system
  • Figure 7 is a schematic view of an individual control system
  • Figure 8 is a cross sectional view of an alternative embodiment of an actuator.
  • Figure 1 illustrates schematically a valve train generally indicated at 10.
  • the valve 11 is controlled by a rocker arm 12 which is itself actuated by a rod 13.
  • a return spring 14 is provided to re-seat the valve.
  • the valve train, or opening means includes an hydraulic section generally indicated at 15. This comprises an open-ended cylinder 16 which is divided by a central wall 17, into upper and lower chambers 18,19 for receiving respective pistons 20,21.
  • the upper piston 20 is coupled to the rod 13, whilst the bottom half 22 of the lower piston 21 is configured as a plate-for engaging a-cam.23.
  • First and second flow paths 24,25 are defined through the central wall.
  • the first is designed to allow flow from the lower chamber 19 to the upper chamber 18 and includes a non-return valve 26.
  • the second, 25, is provided to allow flow in the reverse direction and has a control element 27, which can be inserted and withdrawn at right-angles to the direction of flow therethrough to vary the effective cross- sectional area of the flow path 25 and hence the rate of flow therethrough.
  • the cam is profiled to operate the valve in accordance with the optimal low speed conditions.
  • the cam 23 lifts the lower piston 21 compressing oil in the lower chamber 19 and hence forcing it into the upper chamber 18, with the result that the upper piston 20, and hence the rod 13, is lifted causing opening of the valve 11.
  • the cam passes its peak projection, the movement is reversed due to the action of spring 14.
  • the pistons 20,21 can be caused to return more slowly than would be dictated by the cam 23, with the result that the valve opening time can be adjustably increased.
  • lines A to C represent increasing cross-sections for the second flow path 25, and hence reduced, valve opening times.
  • control element 27 can be achieved in many ways and it is preferred that it should be microprocessor controlled and - 9-
  • Figures 6 and 7 illustrate two mechanical control systems; the first being based on the pressure in the inlet manifold 28, which is converted to mechanical linear movement by a diaphragm spring unit 29 to move a linear cam 30 which causes orthogonal linear movement of a control rod 31 which, in turn, rotates a rocking lever 32.to produce axial movement of the element 27.
  • the Figure 7 embodiment again used a linear cam and is based on the premise that the mean pressure in the lower chamber 19 is a reflection of speed.
  • the linear cam 30 will be moved in accordance with that pressure.
  • a top-up port 33 is provided in the lower chamber and, as is mentioned above this is fed by the engine oil pump. It has been found that in some circumstances it is desirable for this port to enter the upper chamber through the non ⁇ return valve, because when the engine is not in use, the valve 11 will re-seat if the engine is stopped with the valve in its open position, due to hydraulic -1 0-
  • valve train therefore gets out of calibration with the cam. With the top-up port in the upper chamber, the oil pressure provided by the engine pump will lift the upper piston 20 and re-position the valve 11.
  • the second flow path cross-section varies significantly with temperature below about 40°C. For normal running, this does not matter as most modern engines operate at around 100°C, but problems can arise on start-up if the element 27 is under mechanical control. (A micro ⁇ processor can of course allow for such temperature changes) . Accordingly, it is envisaged that the cylinder 16 may be provided with a further bypass between the upper and lower chambers 18,19 for allowing flow from the upper chamber to the lower chamber when the oil temperature is below 40°C. When this temperature is reached, the bypass will be closed off and the second flow path cross-section will control the action of the valve 11. Such a bypass is illustrated in Figure 4.
  • the upper chamber is provided with an oil inlet 40 having a non-return valve 41 ' whilst the lower chamber 19 has a fluid outlet 42 having a non- return valve 43.
  • the first flow path 24 has been dispensed with and instead the upper piston 20 is lifted directly by the lower piston 21 by means of legs (one of which is shown at 44) which support the upper piston 20.
  • legs one of which is shown at 44
  • the cam 23 lifts the lower piston 20
  • oil is pushed out of the chamber 19 through the outlet 42.
  • the upper piston is lifted by legs 44 and draws fresh oil into the chamber 18 via inlet 40.
  • the rate of the return of the upper piston is determined, as before, by the degree to which the passage 25 is restricted by the control element 27.
  • the rate of return of the upper piston 20, and hence the valve 11 can be independent of the rate of return of the lower piston 21.
  • This provides the possibility of 'topping-up' the second chamber 19 through an additional inlet 45.
  • This option could provide two advantages; first, the lower piston 21 can be allowed to stay in contact with the cam 23 at all times, because the upper piston 20 is temporarily disconnected from the lower piston 21 during descent; and second, the pressure in the chamber 19 can be kept up to further reduce frothing of the oil.
  • the passage 25 can be provided in a side wall of the chamber 18 allowing the oil to be passed directly into the engine's oil supply.
  • the oil in the chamber 19 could be replaced by a spring or other bias means arranged to return the lower piston 21 during the return cycle.
  • the upper piston 20 may be integrally formed with or connected to the legs 44 so that the two pistons travel together. In this case, the rate of movement on the upward stroke is determined by the action of the cam on the lower piston 20, whilst the rate of movement on the downward or closing stroke is determined by the degree of damping induced by the control element 27.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Valve Device For Special Equipments (AREA)

Abstract

Actuateur de soupape tel qu'un poussoir hydraulique. Dans une forme d'exécution, le poussoir comprend un cylindre (16) définissant à l'aide d'une paroi centrale (17) des chambres supérieure et inférieure (18, 19). Ces dernières possèdent des pistons respectifs (20 et 21). Le piston (20) est relié à une tige d'actionnement (13) d'une soupape (11), tandis que le piston (21) glisse sur une came (23). La paroi centrale se compose de deux chemins d'écoulement (24 et 25). Le premier permet à l'huile de s'écouler de la chambre (19) vers la chambre (18) pendant la course montante du piston (21), ce qui permet à la came de commander la course montante du piston (20) et l'ouverture de la soupape (11). Lorsque la came (23) retombe, la soupape (11) se referme sous l'action du ressort (14), ce qui produit la course descendante du piston supérieur (20). La vitesse de cette course de retour est déterminée par la vitesse à laquelle l'huile peut s'écouler à travers le passage (25) qui peut être limité de manière variable par l'élément régulateur (27). Par conséquent, grâce au réglage de l'élément régulateur (27), la vitesse de fermeture de la soupape (11) peut être modifiée. Sont également décrites des variantes d'exécution, dans chacune desquelles la course de retour du piston supérieur (20) est amortie de manière variable.
PCT/GB1987/000411 1986-06-12 1987-06-12 Actuateur variable pour une soupape WO1987007677A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE8787903892T DE3770822D1 (de) 1986-06-12 1987-06-12 Verstellbare betaetigungseinrichtung fuer ein ventil.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB868614310A GB8614310D0 (en) 1986-06-12 1986-06-12 Variable actuator
GB8614310 1986-06-12

Publications (1)

Publication Number Publication Date
WO1987007677A1 true WO1987007677A1 (fr) 1987-12-17

Family

ID=10599348

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1987/000411 WO1987007677A1 (fr) 1986-06-12 1987-06-12 Actuateur variable pour une soupape

Country Status (3)

Country Link
EP (1) EP0309468B1 (fr)
GB (2) GB8614310D0 (fr)
WO (1) WO1987007677A1 (fr)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0317371A1 (fr) * 1987-11-19 1989-05-24 Honda Giken Kogyo Kabushiki Kaisha Dispositif de commande de soupape pour moteur à combustion interne
US5421359A (en) * 1992-01-13 1995-06-06 Caterpillar Inc. Engine valve seating velocity hydraulic snubber
US5577468A (en) * 1991-11-29 1996-11-26 Caterpillar Inc. Engine valve seating velocity hydraulic snubber
USRE37604E1 (en) 1991-06-24 2002-03-26 Ford Global Technologies, Inc. Variable engine valve control system
WO2008025704A1 (fr) * 2006-08-30 2008-03-06 Schaeffler Kg Clapet d'étranglement pour un moteur à combustion interne avec commande électrohydraulique du clapet
EP2055906A1 (fr) * 2007-10-31 2009-05-06 Caterpillar Motoren GmbH & Co. KG Dispositif et procédé de contrôle de soupapes
WO2010049583A1 (fr) * 2008-10-29 2010-05-06 Wärtsilä Finland Oy Dispositif de commande pour ensemble d'actionnement de soupape et procédé pour commander le mouvement de fermeture d'un ensemble d'actionnement de soupape

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4102537A1 (de) * 1991-01-29 1992-07-30 Man Nutzfahrzeuge Ag Auslass-ventilstoessel fuer eine brennkraftmaschine
DE4423657C2 (de) * 1994-07-06 1997-10-02 Daimler Benz Ag Betätigungseinrichtung für ein Motorbremsventil einer Brennkraftmaschine
DE10049698A1 (de) * 2000-10-07 2002-04-11 Hydraulik Ring Gmbh Schalteinrichtung zum Schalten von Ein/Auslaßventilen für Verbrennungskraftmaschinen

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1250677B (de) * 1967-09-21 Dipl -Ing Dr Dr h c Hans List, Graz (Osterreich) Hydraulische Steuerungseinrichtung fur Brennkraftmaschmenventile, insbesondere fur die Emblasventile einer Gasmaschine
DE2057667A1 (de) * 1970-11-24 1972-06-08 Willy Bartels Ventilsteuerung eines Kolbenmotors
FR2252023A5 (en) * 1973-11-20 1975-06-13 Chrysler France Shock absorber for IC engine valve tappet - face plates control oil flow around and through damping piston around tappet
US3938483A (en) * 1973-08-20 1976-02-17 Joseph Carl Firey Gasoline engine torque regulator
EP0027949A1 (fr) * 1979-10-26 1981-05-06 Regie Nationale Des Usines Renault Distribution variable à arbre à cames et à soupapes pour moteurs à combustion interne

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1533654A (en) * 1975-12-03 1978-11-29 British Leyland Uk Ltd Internal combustion engine
US4009694A (en) * 1976-04-15 1977-03-01 Joseph Carl Firey Gasoline engine torque regulator with partial speed correction
DE2825316A1 (de) * 1978-06-09 1979-12-20 Maschf Augsburg Nuernberg Ag Regelbare hydraulische ventilsteuerung fuer hubkolbenkraft- oder arbeitsmaschinen
DE3004396A1 (de) * 1980-02-07 1981-08-13 Dr.Ing.H.C. F. Porsche Ag, 7000 Stuttgart Ventilsteuerung fuer brennkraftmaschinen
GB2107393B (en) * 1981-10-20 1984-10-24 Lucas Ind Plc I c engine with a fluid pressure valve operating system
GB2124701B (en) * 1982-07-30 1985-09-11 Lucas Ind Plc Actuating system for engine valves

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1250677B (de) * 1967-09-21 Dipl -Ing Dr Dr h c Hans List, Graz (Osterreich) Hydraulische Steuerungseinrichtung fur Brennkraftmaschmenventile, insbesondere fur die Emblasventile einer Gasmaschine
DE2057667A1 (de) * 1970-11-24 1972-06-08 Willy Bartels Ventilsteuerung eines Kolbenmotors
US3938483A (en) * 1973-08-20 1976-02-17 Joseph Carl Firey Gasoline engine torque regulator
FR2252023A5 (en) * 1973-11-20 1975-06-13 Chrysler France Shock absorber for IC engine valve tappet - face plates control oil flow around and through damping piston around tappet
EP0027949A1 (fr) * 1979-10-26 1981-05-06 Regie Nationale Des Usines Renault Distribution variable à arbre à cames et à soupapes pour moteurs à combustion interne

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0317371A1 (fr) * 1987-11-19 1989-05-24 Honda Giken Kogyo Kabushiki Kaisha Dispositif de commande de soupape pour moteur à combustion interne
USRE37604E1 (en) 1991-06-24 2002-03-26 Ford Global Technologies, Inc. Variable engine valve control system
US5577468A (en) * 1991-11-29 1996-11-26 Caterpillar Inc. Engine valve seating velocity hydraulic snubber
US5421359A (en) * 1992-01-13 1995-06-06 Caterpillar Inc. Engine valve seating velocity hydraulic snubber
WO2008025704A1 (fr) * 2006-08-30 2008-03-06 Schaeffler Kg Clapet d'étranglement pour un moteur à combustion interne avec commande électrohydraulique du clapet
EP2055906A1 (fr) * 2007-10-31 2009-05-06 Caterpillar Motoren GmbH & Co. KG Dispositif et procédé de contrôle de soupapes
US8430072B2 (en) 2007-10-31 2013-04-30 Caterpillar Motoren Gmbh & Co. Kg Device and method for controlling valves
WO2010049583A1 (fr) * 2008-10-29 2010-05-06 Wärtsilä Finland Oy Dispositif de commande pour ensemble d'actionnement de soupape et procédé pour commander le mouvement de fermeture d'un ensemble d'actionnement de soupape

Also Published As

Publication number Publication date
EP0309468B1 (fr) 1991-06-12
EP0309468A1 (fr) 1989-04-05
GB2194587A (en) 1988-03-09
GB8713764D0 (en) 1987-07-15
GB8614310D0 (en) 1986-07-16

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