Internal-combustion engines – Poppet valve operating mechanism – With means for varying timing
Reexamination Certificate
2000-10-18
2001-11-20
Lo, Weilun (Department: 3748)
Internal-combustion engines
Poppet valve operating mechanism
With means for varying timing
C123S090420, C123S19800E
Reexamination Certificate
active
06318317
ABSTRACT:
DESCRIPTION
This invention relates to a device interrupting the force flow between at least one valve and at lease one cam of a camshaft, especially in valve operation of a reciprocating internal combustion engine.
A device such as this is disclosed in DE 27 53 197 A. The coupling element between the first and the second control levers is a pivotably mounted locking member actuated by a rod of an electromagnetic positioning member mounted so as to be stationary. The result is a structure which is relatively costly from the viewpoint of structural space and weight.
Another device for control of different valve control times in a multivalve internal combustion engine is disclosed in reference DE 42 05 230 A1. The device described in this reference has three first levers which are pivotable about a common first axis and each of which operates in conjunction with an intake valve and a cam for a first engine speed range, a second lever which is mounted between the adjacent first levers, and operates in conjunction with a cam for a second engine speed range, and a coupling element between the first set of levers and the second lever, in order to couple and decouple these levers in the first engine speed range. For this purpose the coupling element extends parallel to the axes of rotation of the levers and is rotatable between a first position in which it couples the first and the second levers to each other and a second position in which it uncouples the first and the second levers.
It is the object of this invention to design on the basis of this state of the art a device interrupting the force flow between at least one valve and at least one cam of a camshaft, which device takes up an especially small structural space and accordingly may be employed in very cramped spaces. In addition, this device is to be of a design which is simple and reliable in operation and the manufacture of which is cost-effective.
This object is attained in that the rotating coupling is mounted in the second actuating lever and carries a freely rotating roller which comes into direct contact with the cam of the camshaft. This results in an especially compact structural arrangement with low frictional losses. In addition, a corresponding cam slide surface may be provided on the second actuating lever.
In a development of this invention the rotating coupling element has in the area of its engagement with the first actuating lever a cross-section such that in its first rotary position it engages the undercut of a curved recess in the first actuating lever and is disengaged in its second rotary position. Switching back and forth between coupling or decoupling of the first and second actuating levers can thus be effected by rotation of the coupling element through approximately 120 degrees.
The coupling element can be moved into its first rotary position by means of a first rotating mechanism, into its second rotary position by means of a second mechanical or hydraulic rotating mechanism, and may be kept in its second rotary position by an electromagnetic locking mechanism. A torsion bar, for example, may be suggested for keeping the first rotary mechanism in operation at all times. The second, periodically operating, rotary mechanism may be represented in particular by a special cam on the camshaft.
The first mechanical rotary mechanism thus acts to sustain the first rotary position, which corresponds to the coupled state of the first and second actuating levers, while the second mechanical or hydraulic rotary mechanism serves to sustain the second rotary position, which corresponds to the uncoupled state of the first and second actuating levers. The electromagnetic locking mechanism, in contrast, serves exclusively to maintain the second rotary position.
In order to switch from the coupled to the uncoupled state it is necessary for the constantly acting force of the first mechanical rotary mechanism to be overcome by the periodically or occasionally acting force of the second mechanical rotary mechanism. The electromagnetic locking mechanism is activated only if the periodically recurring second rotary position is to be sustained by the second rotary mechanism, so that the force flow between the valve and the cam of the camshaft is interrupted. In this way the electromagnetic locking mechanism may be relatively small in size, since it performs exclusively a locking function with respect to the coupling element rather than, for example, a movement function.
REFERENCES:
patent: 4762096 (1988-08-01), Kamm et al.
patent: 5544626 (1996-08-01), Diggs et al.
patent: 5622145 (1997-04-01), Hara
patent: 5623897 (1997-04-01), Hampton et al.
patent: 5899180 (1999-05-01), Fischer
patent: 6112711 (2000-09-01), Shimizu et al.
patent: 2753197 (1977-11-01), None
patent: 42 05 230 A1 (1993-08-01), None
patent: 42 26 163 A1 (1994-02-01), None
patent: 295 19 593 U1 (1997-05-01), None
patent: 0 796 982 A1 (1997-09-01), None
patent: 2311179 (1976-12-01), None
patent: WO 94/03709 (1994-02-01), None
Audi AG
Lalos & Keegan
Lo Weilun
LandOfFree
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