EP0309468B1 - Actuateur variable pour une soupape - Google Patents

Actuateur variable pour une soupape Download PDF

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Publication number
EP0309468B1
EP0309468B1 EP87903892A EP87903892A EP0309468B1 EP 0309468 B1 EP0309468 B1 EP 0309468B1 EP 87903892 A EP87903892 A EP 87903892A EP 87903892 A EP87903892 A EP 87903892A EP 0309468 B1 EP0309468 B1 EP 0309468B1
Authority
EP
European Patent Office
Prior art keywords
valve
chamber
piston
cam
actuator
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.)
Expired - Lifetime
Application number
EP87903892A
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German (de)
English (en)
Other versions
EP0309468A1 (fr
Inventor
Stephen John Charlton
David John Bell
Peter Charles Howard
Andrew John Haines
Stuart Lawrence Bird
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.)
University of Bath
Original Assignee
University of Bath
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Publication date
Application filed by University of Bath filed Critical University of Bath
Publication of EP0309468A1 publication Critical patent/EP0309468A1/fr
Application granted granted Critical
Publication of EP0309468B1 publication Critical patent/EP0309468B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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.
  • 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 the cam increases. It has been known for some time that the combustion efficiency and torque of an engine can be improved by 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 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 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 and means for variably damping the closing of the valve by the bias means which acts on at least part of the cam follower to disconnect it, and hence the, valve operatively from the cam characterised in that the cam follower means comprises 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, in response to closing movement of the valve, is vented from the chamber through an outlet port in response to closing movement of the valve and in that damping means comprises a variable restriction in the outlet port.
  • the second chamber may also contain fluid, in which case the central wall may include a fluid flow path from the second chamber to the first chamber, such that cam induced movement of the second piston forces fluid into the first chamber.
  • the outlet port may debouch into the second chamber.
  • 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.
  • 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.
  • the first and second pistons may be effectively integral one with the other.
  • 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 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.
  • 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.
  • control means may vary the rate of flow in accordance with the inlet manifold pressure, the oil pressure, or an engine speed detection device.
  • the valves may be controlled individually, or all the inlet valve may be controlled simultaneously 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.
  • bypass means mentioned above would typically be used at low engine oil temperatures during start-up.
  • the closure of the bypass may be temperature controlled.
  • the profile of the cam is selected in accordance with the desired low speed (e.g. 1,000 r.p.m. and under) performance of the engine and that the outlet port is opened increasingly as engine speed increases.
  • the cylinder and other portions of the opening means may be formed in the engine casing.
  • FIG. 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 movement is reversed due to the action of spring 14.
  • the rate at which the upper piston 20 falls back and hence the rate at which the lower piston 21 moves back to the position in which the bottom half 22 engages the circle of the cam 23, is determined by the rate at which fluid flows back into the lower chamber 19, but it can never be faster than that allowed by the cam 23.
  • 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 electrically driven in accordance with engine speed and optimum operated engine conditions pre-programmed into the processor.
  • Such facilities are currently only available on the most up-market ranges of cars, and so mechanical control may be needed in the mass market.
  • 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 10 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 urper 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 oil leakage. The 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 microprocessor 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.
  • cavitation or frothing of the oil may occur in the second chamber 19. It is considered that this may be reduced or overcome by replacing at least part of the oil in the chambers 18, 19 in each cycle.
  • Figure 8 One arrangement for achieving this is illustrated in Figure 8.
  • 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.
  • 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.
  • 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.

Claims (11)

1. Organe de manoeuvre (10) de soupape (11) comprenant un dispositif de rappel (14) destiné à repousser la soupape (11) en position de fermeture et un dispositif (15, 23) destiné à ouvrir la soupape (11) malgré la force du dispositif de rappel (14) et comprenant une came (23) et un toucheau (15) de came destiné à provoquer l'ouverture de la soupape (11) lors du déplacement provoqué par la came (23) dans un premier sens, et un dispositif (27) destiné à amortir de manière variable la fermeture de la soupape sous l'action du dispositif de rappel et qui agit sur une partie au moins du toucheau de came (15) d'une manière telle que le toucheau, et en conséquence la soupape (11), sont déconnectés de la came (23), caractérisé en ce que le dispositif (15) à toucheau de came comporte un corps creux et allongé (16) qui est divisé en une première et une seconde chambre (18, 19) par une paroi (17) centrale de façon générale, un piston de manoeuvre (20) destiné à déplacer la soupape (11) et placé dans la première chambre (18), un second piston (21) commandé par la came et placé dans la seconde chambre, et un dispositif destiné à raccorder le premier, et le second piston de manière que la soupape (11) soit ouverte par le premier piston (20) à la suite du déplacement du second piston (21) provoqué par la came, la première chambre (18) contenant un fluide qui, à la suite du mouvement de fermeture de la soupape (11), est évacué de la chambre par un canal de sortie (25) à la suite du mouvement de fermeture de la soupape (11), et en ce que le dispositif d'amortissement (22) comporte un rétrécissement variable (27) placé dans le canal de sortie (25).
2. Organe de manoeuvre selon la revendication 1, dans lequel la seconde chambre (19) contient aussi du fluide, et la paroi centrale (16) comporte un trajet (24) de circulation de fluide de la seconde chambre (19) à la première (18) afin que le déplacement du second piston (21) provoqué par la came chasse le fluide dans la première chambre (18).
3. Organe de manoeuvre selon la revendication 2, dans lequel le canal de sortie (25) débouche dans la seconde chambre (19).
4. Organe de manoeuvre selon la revendication 2 ou 3, dans lequel le corps (16) a une entrée de fluide et une sortie de fluide, si bien que le fluide du dispositif (15) à toucheau de came est changé à chaque cycle à la suite du déplacement de l'un des pistons (20, 21) ou des deux.
5. Organe de manoeuvre selon la revendication 4, dans lequel l'entrée de fluide (40) est connectée à la première chambre (18) et la sortie de fluide (41) est connectée à la seconde chambre (19).
6. Organe de manoeuvre selon la revendication 4 ou 5, dans lequel une entrée supplémentaire (45) de fluide est connectée à la seconde chambre (19) et est destinée à transmettre du fluide sous pression de manière que le second piston (21) soit maintenu au contact de la came (23) pendant la partie de fermeture de soupape du cycle.
7. Organe de manoeuvre selon l'une quelconque des revendications 2 à 6, dans lequel le transfert de fluide par le trajet (24) de circulation de fluide donne un mouvement d'ouverture de soupape au premier piston (20) à la suite du déplacement du second piston (21) sous l'action de la came.
8. Organe de manoeuvre selon l'une quelconque des revendications 2 à 6, comprenant en outre un dispositif de support (44) monté sur le second piston (21) et destiné à déplacer le premier piston (20) pendant la partie d'ouverture de soupape du cycle tout en permettant un déplacement indépendant des pistons (20, 21) pendant la partie de fermeture de soupape du cycle.
9. Organe de manoeuvre selon l'une quelconque des revendications 2 à 5, dans lequel le premier et le second piston (20, 21) sont solidaires.
10. Moteur à combustion interne, comprenant un organe de manoeuvre de soupape selon l'une quelconque des revendications précédentes.
11. Moteur selon la revendication 10, dans lequel le dispositif d'amortissement est commandé en fonction d'un paramètre du fonctionnement qui représente ou reflète la vitesse du moteur.
EP87903892A 1986-06-12 1987-06-12 Actuateur variable pour une soupape Expired - Lifetime EP0309468B1 (fr)

Applications Claiming Priority (2)

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

Publications (2)

Publication Number Publication Date
EP0309468A1 EP0309468A1 (fr) 1989-04-05
EP0309468B1 true EP0309468B1 (fr) 1991-06-12

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ID=10599348

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EP87903892A Expired - Lifetime EP0309468B1 (fr) 1986-06-12 1987-06-12 Actuateur variable pour une soupape

Country Status (3)

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

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01134018A (ja) * 1987-11-19 1989-05-26 Honda Motor Co Ltd 内燃機関の動弁装置
DE4102537A1 (de) * 1991-01-29 1992-07-30 Man Nutzfahrzeuge Ag Auslass-ventilstoessel fuer eine brennkraftmaschine
US5255641A (en) 1991-06-24 1993-10-26 Ford Motor Company Variable engine valve control system
EP0614507B1 (fr) * 1991-11-29 1996-09-25 Caterpillar Inc. Ralentisseur hydraulique de la vitesse de fermeture d'une soupape de moteur sur un siege de soupape
US5421359A (en) * 1992-01-13 1995-06-06 Caterpillar Inc. Engine valve seating velocity hydraulic snubber
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
DE102006040671A1 (de) * 2006-08-30 2008-03-06 Schaeffler Kg Drosselventil für eine Brennkraftmaschine mit elektrohydraulischer Ventilsteuerung
EP2055906A1 (fr) 2007-10-31 2009-05-06 Caterpillar Motoren GmbH & Co. KG Dispositif et procédé de contrôle de soupapes
FI121245B (fi) * 2008-10-29 2010-08-31 Waertsilae Finland Oy Ohjausjärjestely venttiilien käyttökoneistolle ja menetelmä venttiilien käyttökoneiston sulkemisliikkeen ohjaamiseksi

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2124701A (en) * 1982-07-30 1984-02-22 Lucas Ind Plc Actuating system for engine valves

Family Cites Families (10)

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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
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
FR2468732A1 (fr) * 1979-10-26 1981-05-08 Renault Distribution variable a commande hydraulique pour moteurs a combustion interne
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

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2124701A (en) * 1982-07-30 1984-02-22 Lucas Ind Plc Actuating system for engine valves

Also Published As

Publication number Publication date
WO1987007677A1 (fr) 1987-12-17
GB8713764D0 (en) 1987-07-15
GB8614310D0 (en) 1986-07-16
EP0309468A1 (fr) 1989-04-05
GB2194587A (en) 1988-03-09

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