U.S. patent application number 09/775757 was filed with the patent office on 2001-08-09 for device for operating a gas exchange valve of an internal combustion engine.
Invention is credited to Gaisberg, Alexander Von, Stolk, Thomas.
Application Number | 20010011533 09/775757 |
Document ID | / |
Family ID | 7630044 |
Filed Date | 2001-08-09 |
United States Patent
Application |
20010011533 |
Kind Code |
A1 |
Stolk, Thomas ; et
al. |
August 9, 2001 |
Device for operating a gas exchange valve of an internal combustion
engine
Abstract
In a device for operating a gas exchange valve of an internal
combustion engine having an electromagnetic actuator including a
valve opening magnet and a valve closing magnet, between which
there is arranged an armature which, together with an opening
spring, engages a valve stem against the force of a closing spring,
and a hydraulic play-compensating element is arranged in the valve
operating force transmission structure, the hydraulic
play-compensating element is installed in the transmission
structure together with a mechanical adjusting element providing
for minimal valve play when the engine is shut down.
Inventors: |
Stolk, Thomas; (Kirchheim,
DE) ; Gaisberg, Alexander Von; (Fellbach,
DE) |
Correspondence
Address: |
Klaus J. Bach
4407 Twin Oaka Drive
Murrysville
PA
15668
US
|
Family ID: |
7630044 |
Appl. No.: |
09/775757 |
Filed: |
February 5, 2001 |
Current U.S.
Class: |
123/90.11 ;
123/90.55 |
Current CPC
Class: |
F01L 9/20 20210101; F01L
1/24 20130101 |
Class at
Publication: |
123/90.11 ;
123/90.55 |
International
Class: |
F01L 009/04; F01L
001/14 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 5, 2000 |
DE |
100 05 247.9 |
Claims
What is claimed is:
1. A device for operating a gas exchange valve with a valve stem of
an internal combustion engine, having an operating mechanism with
an electromagnetic actuator including a valve opening magnet and a
valve closing magnet arranged in axially spaced relationship, an
armature movably disposed between said valve opening and closing
magnets, a valve opening spring acting on said valve stem in a
valve opening direction and a valve closing spring acting on said
valve stem in a valve closing direction against the force of said
valve opening spring and a hydraulic play-compensating element
arranged in said device for adjustment of the play in said
operating mechanism, and a mechanical play-compensating element
selected and installed in said operating mechanism during assembly
of said device so as to provide minimal valve play when said
internal combustion engine is not operating.
2. A device according to claim 1, wherein said mechanical
play-compensation element is one of an adjustment disc an eccentric
shaft and a setting screw.
3. A device according to claim 1, wherein said electromagnetic
actuator is movably supported in a housing of said internal
combustion engine via said mechanical play-compensating element,
said mechanical play-compensation element being disposed between
said actuator and said hydraulic play-compensating element.
4. A device according to claim 1, wherein said electromagnetic
actuator is movably supported in a housing of said internal
combustion engine via said mechanical play-compensating element,
said mechanical play-compensation element being disposed between
said hydraulic play compensating element and said housing
and/or.
5. A device according to claim 1, wherein said electromagnetic
actuator is movably supported in a housing of said internal
combustion engine via said mechanical play-compensating element,
said mechanical play-compensation element being disposed between a
play compensating element securing means and said housing.
6. A device according to claim 1, wherein said armature acts on the
valve stem of said gas exchange valve via an armature tappet, and
said hydraulic play-compensating element is arranged between the
armature tappet and the valve stem and has an end recess in which
said mechanical adjusting element is disposed, said armature tappet
being supported on said mechanical adjusting element.
Description
BACKGROUND OF THE INVENTION
[0001] The invention relates to a device for operating a gas
exchange valve of an internal combustion engine with an
electromagnetic actuator which includes an opening magnet and a
closing magnet and an armature movably disposed between the opening
and closing magnets for operating a valve shaft against the force
of a closing spring.
[0002] Electromagnetic actuators for actuating gas exchange valves
usually have two operating magnets, a valve opening magnet and a
valve closing magnet, with opposite pole faces between which an
armature is arranged. The armature acts directly or indirectly on a
valve stem of the gas exchange valve. Actuators operating in
accordance with the principle of mass-oscillation include a spring
mechanism, wherein two springs act on the armature in opposite
directions. Usually, two pre-stressed compression springs are used
as the spring mechanism, of which one is a valve opening spring
which biases the gas exchange valve in the valve opening direction
and the other is a valve closing spring, which biases the gas
exchange valve in the valve closing direction. When the magnets are
not excited, the armature is retained by the valve springs in a
position of equilibrium between the two magnets. This position
corresponds to a center position, that is an equilibrium position
of energy, between the two springs.
[0003] DE 35 13 107 C2 discloses a gas exchange valve with an
actuator in which the armature, together with an opening spring,
acts on the valve stem, via an armature tappet, against the force
of a closing spring, which acts on the valve stem of the gas
exchange valve.
[0004] DE 39 20 931 A1 discloses an electromagnetic actuator for
gas exchange valves of displacement engines, in particular of
internal combustion engines, which operates one or more gas
exchange valves via a lever mechanism. The lever mechanism provides
for a variable motion transmission between the actuator and the gas
exchange valve. A play-compensating element compensates for the
play, which is caused by the transmission system or which develops
therein. The play-compensating element may be arranged in various
positions in the transmission system either on the side of the gas
exchange valve or on the side of the magnet, e.g. between the
support structure of the lever system or between the closing magnet
and the housing. The play compensation arrangement also includes a
structure common to the gas exchange valve, or individual
adjustment devices for changing the transmission ratios and to
adapt the position of equilibrium of the oscillating system to the
new spring forces by changing the position of one or more spring
support points.
[0005] DE 39 20 976 A1 discloses a similar adjusting device in
which a hydraulic play-compensating element is supported in the
armature and engages the valve stem of the gas exchange valve. The
play-compensating element may be supplied with oil under pressure
via the armature. Also provided is a setting screw which is
inserted in a top cover and acts on one support point of an opening
spring which, with its other support point, engages the armature.
By virtue of the setting screw, the position of equilibrium of the
armature is adjustable such that the armature rests in the center
between the operating magnets when the magnets are
de-energized.
[0006] When the internal combustion engine is at a standstill, the
hydraulic play-compensating element empties whereby the
pre-determined position of equilibrium is changed in the direction
toward the opening magnet. When the internal combustion engine is
then started up again, the closing magnet has to generate a
relatively high force. This causes a high mechanical, electrical
and thermal load. Furthermore, in the closed position of the
armature, there is a relatively large gap between the
play-compensating element and the valve stem, which results in an
annoying noise. In many cases, oscillation excitation of the system
is not possible.
[0007] It is the object of the invention, to improve the start-up
capabilities of an internal combustion engine controlled via
electromagnetic actuators.
SUMMARY OF THE INVENTION
[0008] In a device for operating a gas exchange valve of an
internal combustion engine having an electromagnetic actuator
including an opening magnet and a closing magnet, between which
there is arranged an armature which, together with an opening
spring, engages a valve stem against the force of a closing spring,
and a hydraulic play-compensating element arranged in the valve
operating force transmission structure, the play-compensating
element is installed in the transmission structure together with a
mechanical adjusting element providing for minimal valve play when
the engine is shut down.
[0009] The mechanical play compensating element compensates for all
deviations or tolerances resulting from the manufacture so that the
hydraulic play-compensating element need only compensate for the
changes in length resulting from the operation of the internal
combustion engine. As a result, any gap between the
play-compensating element and the adjacent component is minimal
when the engine is started up again after stand-still, with the
result that no significant noise or excessive mechanical,
electrical or thermal loading is generated. Operation of the
internal combustion engine is possible however also with a
defective mechanical play-compensating element.
[0010] The adjusting element may simply comprise an adjusting disc,
an eccentric shaft or a setting screw. It may be arranged ranged at
various locations of the device, so that there is a high level of
design freedom.
[0011] Further embodiments and advantages of the invention will
become apparent from the following description of the invention on
the basis of the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 shows, schematically, a device according to the
invention having a hydraulic play-compensating structure shown in a
position as it is during operation of the internal combustion
engine or shortly after the engine has come to a standstill,
[0013] FIG. 2 shows a device according to FIG. 1 while the internal
combustion engine is at a standstill and the oil has drained from
the hydraulic play-compensating structure,
[0014] FIG. 3 shows a device according to FIG. 1 of the internal
combustion engine immediately after start-up before the hydraulic
play compensation structure has been readjusted,
[0015] FIG. 4 shows an enlarged detail area as indicated by the
circle IV in FIG. 1, and
[0016] FIG. 5 shows, in detail, another embodiment of the
invention, that is, a variant from the arrangement of FIG. 1.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0017] In the arrangement 1 of the invention as shown in FIG. 1, an
electromagnetic actuator 11 operates a gas exchange valve 2 in the
cylinder head 33 (FIG. 5) of an internal combustion engine. The
actuator 11 has a top closing magnet 15 and a bottom opening magnet
16 as well as an armature 12, which is arranged axially movably
between the magnets 15 and 16. The armature 12 acts on a valve stem
4 of the gas exchange valve 2 via an armature tappet 13 and a
play-compensating element 10. Located at the free end of the valve
stem 4 is a valve disc 3, which interacts with a valve seat ring 6
positioned in the cylinder head 33. A valve guide 5 guides the
valve stem 4 in the cylinder head 33. For the sake of clarity, the
cylinder head 33 has not been illustrated in FIGS. 1-4.
[0018] A pre-stressed spring system, comprising a valve closing
spring 7 and a valve opening spring 17, retains the armature 12 in
a position of equilibrium when the magnets 15, 16 are de-energized.
The position of equilibrium corresponds generally to a center
position 19 with regard to the energy of the two springs 7 and 17.
The closing spring 7 is supported at one end, on the cylinder head
33 via a spring support structure 8 and, at the other end, on the
valve stem 4 via a closing spring support plate 9. The opening
spring 17 is supported, at one end, on the actuator 11 and, at its
other end, on the armature tappet 13 via an opening spring plate
18.
[0019] FIG. 1 shows the armature 12 during engine operation in the
center position 19 between the two magnets 15 and 16. During engine
operation the play-compensating element 10 is activated and ensures
that the gas exchange valve 2 closes in a play-free manner. Then in
the closed position 21, that is, with the gas exchange valve 2
closed, the armature 12 butts against the closing magnet 15. The
closing spring 7, which is pre-stressed, engages the gas exchange
valve 2 with a predetermined closing force.
[0020] The play-compensating element 10 includes a cylinder 24
which butts against the valve stem 4 and in which a piston 25 is
arranged in an axially movable manner. Together with the cylinder
24, the piston 25 forms a pressure space 26. Located in the latter
is a spring 30 which biases the piston 25 against the armature
tappet 13, which is disposed in a recess 31 at the free end side of
the piston 25. The pressure space 26 is connected to an oil supply
via a connection bore 14 in the armature tappet 13 and a connecting
bore 27 in the piston 25. A ball 28, which is biased into a bore
closing position by a spring 29 forms a check valve opening in the
direction of the pressure space 26. It controls fluid flow from the
connecting bore 27 out of the pressure space 26 valve. If the
pressure prevailing in the pressure space 26 is lower than in the
connecting bore 27, because, for example, the valve disc 3 butts
against the valve seat ring 6 before the armature 12 reaches the
closing magnet 15, the ball 28 is unseated against the force of the
spring 29 and oil flows into the pressure space 26. In this way,
the piston 25 is adjusted axially until the armature 12 engages the
closing magnet 15 when the gas exchange valve 2 is closed.
[0021] When the internal combustion engine is at a standstill, the
valve closing spring 7 and the valve opening spring 17 subject the
play-compensating element 10 to a loading, whereby the oil escapes
from the pressure space 26 via throttle gaps provided (but not
illustrated specifically). As a result, the play-compensating
element 10 is compressed to the fullest extent. Accordingly, the
position of equilibrium 20 of the armature 12 is changed in the
direction toward the opening magnet 16 (FIG. 2). This means that,
when the internal combustion engine is started up again, a gap 22
is formed between the play-compensating element 10 and the valve
stem 4 when the armature 12 is located in a closed position 21
(FIG. 3) and the armature engages the closing magnet 15. The gap 22
makes correct functioning of the gas exchange valve 2 more
difficult or disrupts operation completely. According to the
invention, minimal valve play is therefore set during the
installation by an adjusting element in the form of an adjusting
disc 23, 32, 37, 39 or in the form of a setting screw 35. For this
purpose, the distance between the parts adjacent to the
play-compensating element 10, e. g. the distance between the valve
stem 4 and the armature tappet 13, is measured when the valve 2 is
closed and the armature 12 engages the closing magnet 15. The fully
compressed length of the play-compensating element 10 is subtracted
from this measurement. The remainder gives the desired thickness of
the adjusting discs 23, 32, 37, 39 plus a minimal valve play. The
setting screw 35 is to be turned accordingly. Instead of the
adjusting disc 23, 32, 37, 39 or the setting screw 35, it is also
possible to use other mechanical adjusting elements, e.g. an
eccentric shaft (not illustrated specifically) or the like. The
adjusting elements 23, 32, 37, 39 may be arranged in any desired
position in the force transmission path of the play-compensating
element 10.
[0022] In the embodiments according to FIGS. 1 to 3, an adjusting
disc 23 is provided beneath the opening magnet 16. It is
alternatively possible to arrange an adjusting disc 32 in the
opening 31 of the piston 25 of the play-compensating element 10
(FIG. 4). In the exemplary embodiment according to FIG. 5, three
alternatives are illustrated. The first alternative consists of an
adjusting disc 37, which is installed between a securing means in
the form of a cover 36 and the cylinder head 33. Further, the
actuator 11, which is arranged in a floating manner in the cylinder
head 33, may be supported on the cover 36 via the play-compensating
element 10. As an alternative to the adjusting disc 37, it is
possible to provide a setting screw 35 in the cover 36, the
play-compensating element 10 being supported on the setting screw
35. As a third alternative, an adjusting disc 39 may be positioned
between the actuator 11 and the play-compensating element 10 may be
supported thereon. Hydraulic fluid is fed to the play-compensating
element 10 via a supply line 34.
[0023] With a proper selection of the adjusting elements 23, 32,
37, 39, the internal combustion engine can be started up again with
a minimal gap 22 so that the loading of the components and
development of noise are minimized.
* * * * *