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GB2068495A - I.C. engine valve lift hydraulic adjusting device - Google Patents

I.C. engine valve lift hydraulic adjusting device Download PDF

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Publication number
GB2068495A
GB2068495A GB8102182A GB8102182A GB2068495A GB 2068495 A GB2068495 A GB 2068495A GB 8102182 A GB8102182 A GB 8102182A GB 8102182 A GB8102182 A GB 8102182A GB 2068495 A GB2068495 A GB 2068495A
Authority
GB
United Kingdom
Prior art keywords
piston
control
valve
bore
control member
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Withdrawn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
GB8102182A
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.)
Daimler Benz AG
Original Assignee
Daimler Benz AG
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 Daimler Benz AG filed Critical Daimler Benz AG
Publication of GB2068495A publication Critical patent/GB2068495A/en
Withdrawn legal-status Critical Current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
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/20—Adjusting or compensating clearance
    • F01L1/22—Adjusting or compensating clearance automatically, e.g. mechanically
    • F01L1/24—Adjusting or compensating clearance automatically, e.g. mechanically by fluid means, e.g. hydraulically
    • F01L1/2405—Adjusting or compensating clearance automatically, e.g. mechanically by fluid means, e.g. hydraulically by means of a hydraulic adjusting device located between the cylinder head and rocker arm
    • 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
    • F01L13/0021—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 rocker arm ratio

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

Abstract

A hydraulic adjusting device for the valves of a reciprocating piston internal combustion engine acts on the associated valve stem (3) through a lever (4) actuated by a cam (1) of a camshaft (2). The valve opening is controlled and adjusted in accordance with engine speed and/or load by an adjustable bearing assembly (5) including a piston (6) provided with a recess (12) having a control edge (13) which in accordance with movement of the piston (6) controls the flow of lubricating oil from an inlet (15) controlled by a valve (16) to an outlet (17). Closure of the outlet (17) by the control edge (13) establishes a fixed hydraulic connection between the piston (6) and its cylinder (8). Means (18) are provided on the piston stem (7) to control the piston stroke. In one embodiment of the invention the lever (4) is omitted and the cam (1) acts directly on a hollow tappet (21) which includes the control edge (13) and which acts on the valve stem (3) through an internal, axially displaceable piston (24). <IMAGE>

Description

SPECIFICATION Hydraulic adjusting device for the valves of a reciprocating-piston internal-combustion engine.
The invention relates to a hydraulic adjusting device for the valves of a reciprocating-piston internal-combustion engine, by means of which the valve opening is adjusting in accordance with engine speed and load conditions.
In a known device for actuating internal combustion engine valves, (German Offenlegungesschrift 1,958,627), the adjustment of the valve lift is effected automatically. At a high engine speed, oil under pressure, in a pressure space constituted between an outer and an inner tappet, hardly has time to escape through an outlet bore which is designed as a throttle and which is to be closed by a control cam.
Consequently, a change in the valve lift scarcely occurs and the valve aquires a large opening angle.
At a low engine speed, the oil escapes through the throttle and the valve lift starts a certain time later and ceases earlier.
This device, in which the valve lift is established automatically, has the disadvantage that it is not possible to determine the valve lift exactly.
Futhermore, there is the danger that, beyond a certain degree of wear of the tappet piston head, a hydraulic linkage can occur and, consequently, changes in valve lift in respect of engine speed are no longer possible.
The present invention seeks to provide a device which eliminates the disadvantages described and with which the hydraulic adjustment of the valve lift of the valves can be obtained in a simple, economical and precise manner.
According to the invention, there is provided a hydraulic adjusting device for the valves of a reciprocating-piston internal-combustion engine, in which a spring-loaded piston, which is connected to part of the valve gear, is located, in the cylinder head, movably in a chamber against the control-cam pressure and the chamber is connected to an inlet bore and an outlet bore, of which the inlet bore, having a check valve, is connected to the oil circuit of the internalcombustion engine, wherein the outlet bore is a control bore which is controlled by means of a control member provided with a control edge.
By means of this and the measures to be described below, it is possible to achieve optimum adaptation of the control times of the valve lift at different load and engine-speeds points within the operating performance characteristics. As a result, for example in the idling range of the internalcombustion engine, short valve opening times, with a small valve lift, are possible, whilst in the range of maximum torque or maximum power correspondingly long opening times and valve lifts can be realised.
In a preferred embodiment of the invention, the control member can, at the same time, be a piston which has a laterally formed reamed recess constituting the control edge which runs diagonally in the axial direction of the piston.
For the case where the valves are actuated by means of oscillating levers or rocker arms, the piston can be part of an abutment which is provided for a transmission element of the valve gear and which is located in the cylinder head.
A further advantageous embodiment is obtained due to the fact that the control member is designed as a cupped or hollow tappet which has a passage with the control edge running diagonally in the axial direction of the cupped tappet.
Embodiments of the invention will now be described in more detail below, by way of example and with reference to the accompanying drawings, in which: Figure 1 shows a device for the hydraulic adjustment of the valve lift of a valve, in section, this device being part of an abutment for an oscillating lever of the valve gear, Figure 2 shows a constructively similar device, in section, this device forming part of a rocker arm bearing, and Figure 3 shows, in section, another embodiment of the hydraulic adjusting device which is located between the control cam and the valve stem.
In Figure 1, between the control cam 1 of a camshaft 2 and the valve stem 3 of a valve, an oscillating lever 4 is provided, the oscillating-lever bearing assembly 5 of which consists of a piston 6 with a piston stem 7 and of a cylinder liner 10 which is fitted firmly in a cylindrical member 8 inserted in the cylinder head 9 of a reciprocatingpiston internal-combustion engine. The piston 6 is guided for longitudinal displacement in the cylinder liner 10 in which a compressing spring 11 is also located and is pushed by the latter against the oscillating lever 4 which is held, in this way, in constant contact with the control cam 1.
The piston 6 is provided on its outer surface with a reamed recess 12, which runs in the longitudinal direction of the piston and the resulting edge of which is designed as a control edge 13. The space lying underneath the piston 6 containing the spring 11 is simultaneously a pressure space 14. An inlet bore 15, which is connected to the oil circuit of the internalcombustion engine and which has a check valve 16, opens into this pressure space 14. The pressure space 14 is provided with an outlet bore 17 in.the cylinder head 9 communicating with the reamed recess 12 in the piston 6.The outlet bore 17 is, at the same time, a control bore, since it can be controlled by the control edge 1 3. This is effected in such a way that an adjusting element 18, which works in dependence on the load and/or engine speed and which is designed as a rack and meshes with teeth on the piston 6, determines the position of the control edge 1 3 in respect of the control bore 17. If the control edge 1 3 closes the control bore 1 7 completely, then a hydraulic linkage or cushion is obtained in the oscillatinglever bearing. The position of the pivotal point of the oscillating lever is thereby maintained unchanged and the cam lift is correspondingly transmitted to the valve.
At the end of the cam stroke, the force of the compression spring 11 opens the inlet bore 1 5 and the pressure space 14 is filled again through the checkvalve 1 6 with oil under pressure.
The embodiment shown in Figure 2 corresponds in general to the above-described embodiment illustrated in Figure 1.
In this embodiment, however, the oscillating lever is replaced as the transmission element by a rocker arm 19. Other reference numerals correspond to those shown in Figure 1. Because of the different transmission element, a new position of the inlet bore is also established, the inlet bore now being connected, through an additional bore 20 in the cylinder liner 10, to the pressure space 14, lying above the piston 6.
In the embodiment shown in Figure 3, a cupped hollow tappet 21, which is arranged between the control cam 1 and valve stem 3, serves as the transmission element. A passage 23, which is provided with the control edge 13, is located in the cylindrical part 22 of the tappet 21. Here, the pressure space 14 is limited by a cup-like piston 24 which rests on the valve stem 3 and which is guided longitudinally displaceably in the external cupped tappet 21 against a compression spring 25. To control the bore, the adjusting element 18 is, again, provided, and is connected to the rotatable cupped tappet 21.
Located in the cylindrical part 22 of the cupped tappet 21 is a slot 26 which enables the hydraulic oil to pass from the inlet bore 1 5 into the pressure space 14.
The adjustment of the control members 6 and 21 by the adjusting element 18 designed as a rack is effected in the base circle phase of the cam 1.
Optionally, an adjustment of the adjusting member could also be carried out both in the base circle phase and in the active phase of the cam, for example by hydraulic means.

Claims (8)

1. A hydraulic adjusting device for the valves of a reciprocating-piston internal-combustion engine, in which a spring-loaded piston, which is connected to a part of the valve gear, is located, in the cylinder head, movably in a chamber against the control-cam pressure and the chamber is connected to an inlet bore and an outlet bore, of which the inlet bore, having a check valve, is connected to the oil circuit of the internalcombustion engine, wherein the outlet bore is a control bore which is controlled by means of a control member provided with a control edge.
2. A device according to Claim 1, wherein the control member is a piston which has a laterally reamed recess constituting the control edge which runs diagonally in the axial direction of the piston.
3. A device according to Claim 1 or Claim 2, charactersied in that the control member is part of an abutment which is provided for a transmission element of the valve gear and which is located in the cylinder head.
4. A device according to Claim 1, wherein the control member is a cupped hollow tappet which has a passage constituting the control edge which runs diagonally in the axial direction of the cupped tappet.
5. A device adcording to Claim 1 and Claim 4 wherein a piston, which is connected firmly to the end of the valve stem, is guided in the cupped hollow tappet.
6. A device according to Claim 5, wherein a further passage which is in the form of a slot and which interacts with the inlet bore, is provided in the cupped hollow tappet.
7. A device according to anyone of the preceding claims, wherein an adjusting element, which works in dependence on the engine speed and/or load, is non-rotatably connected to the control member.
8. A hydraulic adjusting device for the valves of a reciprocating piston internal combustion engine substantially as herein before described with reference to Figure 1, Figure 2 or Figure 3 of the accompanying drawings.
GB8102182A 1980-02-01 1981-01-23 I.C. engine valve lift hydraulic adjusting device Withdrawn GB2068495A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19803003569 DE3003569A1 (en) 1980-02-01 1980-02-01 DEVICE FOR HYDRAULICALLY ADJUSTING THE VALVE LIFT OF GAS EXCHANGE VALVES OF A PISTON PISTON COMBUSTION ENGINE

Publications (1)

Publication Number Publication Date
GB2068495A true GB2068495A (en) 1981-08-12

Family

ID=6093430

Family Applications (1)

Application Number Title Priority Date Filing Date
GB8102182A Withdrawn GB2068495A (en) 1980-02-01 1981-01-23 I.C. engine valve lift hydraulic adjusting device

Country Status (2)

Country Link
DE (1) DE3003569A1 (en)
GB (1) GB2068495A (en)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4475497A (en) * 1981-11-04 1984-10-09 Honda Giken Kogyo Kabushiki Kaisha Internal combustion engine having an intake/exhaust valve assembly and hydraulic means for rendering the valve assembly inoperative
US4502426A (en) * 1982-05-17 1985-03-05 Skelley James H Variable valve lift and timing mechanism
FR2566836A1 (en) * 1984-06-29 1986-01-03 Honda Motor Co Ltd VALVE OPERATION MECHANISM FOR INTERNAL COMBUSTION ENGINE
DE4105194A1 (en) * 1991-02-20 1992-08-27 Bayerische Motoren Werke Ag Actuator for IC engine valve - involves supporting rocker arm between two points with swivelling adjustment
EP0814240A1 (en) * 1996-06-11 1997-12-29 Ricardo Consulting Engineers Limited Hydraulic tappets
WO1999056008A1 (en) * 1998-04-29 1999-11-04 INA Wälzlager Schaeffler oHG Support element for a cam follower of a valve gear of an internal combustion engine
DE19914044A1 (en) * 1999-03-27 2000-09-28 Schaeffler Waelzlager Ohg Tappet built into cylinder head of engine valve drive, with axis led into elongated hole in bearing block on cylinder head
WO2010049324A1 (en) * 2008-10-30 2010-05-06 Schaeffler Technologies Gmbh & Co. Kg Valve drive of an internal combustion engine having a support element that can be switched off
FR3004752A1 (en) * 2013-04-22 2014-10-24 Peugeot Citroen Automobiles Sa COMBUSTION ENGINE OF A MOTOR VEHICLE WITH HYDRAULIC CYLINDER DEACTIVATION

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT404288B (en) * 1986-10-30 1998-10-27 Avl Verbrennungskraft Messtech ENGINE BRAKE IN AN INTERNAL COMBUSTION ENGINE FOR MOTOR VEHICLES
DE102006007121A1 (en) * 2006-02-16 2007-08-23 Daimlerchrysler Ag Gas control valve especially in vehicle has a hydraulic control element to vary the stroke of the valve
DE102006033403A1 (en) * 2006-07-19 2008-01-24 Mahle International Gmbh cam drive

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4475497A (en) * 1981-11-04 1984-10-09 Honda Giken Kogyo Kabushiki Kaisha Internal combustion engine having an intake/exhaust valve assembly and hydraulic means for rendering the valve assembly inoperative
US4502426A (en) * 1982-05-17 1985-03-05 Skelley James H Variable valve lift and timing mechanism
FR2566836A1 (en) * 1984-06-29 1986-01-03 Honda Motor Co Ltd VALVE OPERATION MECHANISM FOR INTERNAL COMBUSTION ENGINE
DE4105194A1 (en) * 1991-02-20 1992-08-27 Bayerische Motoren Werke Ag Actuator for IC engine valve - involves supporting rocker arm between two points with swivelling adjustment
EP0814240A1 (en) * 1996-06-11 1997-12-29 Ricardo Consulting Engineers Limited Hydraulic tappets
WO1999056008A1 (en) * 1998-04-29 1999-11-04 INA Wälzlager Schaeffler oHG Support element for a cam follower of a valve gear of an internal combustion engine
US6314927B1 (en) 1998-04-29 2001-11-13 Ina Walzlager Schaeffler Ohg Support element for a finger lever of a valve gear of an internal combustion engine
DE19914044A1 (en) * 1999-03-27 2000-09-28 Schaeffler Waelzlager Ohg Tappet built into cylinder head of engine valve drive, with axis led into elongated hole in bearing block on cylinder head
US6220213B1 (en) 1999-03-27 2001-04-24 Ina Walzlager Schaeffler Ohg Rocker arm installed in a cylinder head of a valve train of an internal combustion engine
WO2010049324A1 (en) * 2008-10-30 2010-05-06 Schaeffler Technologies Gmbh & Co. Kg Valve drive of an internal combustion engine having a support element that can be switched off
FR3004752A1 (en) * 2013-04-22 2014-10-24 Peugeot Citroen Automobiles Sa COMBUSTION ENGINE OF A MOTOR VEHICLE WITH HYDRAULIC CYLINDER DEACTIVATION

Also Published As

Publication number Publication date
DE3003569A1 (en) 1981-08-06

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WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)