U.S. patent application number 09/778795 was filed with the patent office on 2001-08-30 for gas exchange valve control for internal combustion engines with an electromagnetic actuator, equipped with gas springs.
This patent application is currently assigned to Bayerische Motoren Werke Aktiengesellschaft.. Invention is credited to Meissner, Frank, Steffens, Hans-Joerg.
Application Number | 20010017113 09/778795 |
Document ID | / |
Family ID | 7632458 |
Filed Date | 2001-08-30 |
United States Patent
Application |
20010017113 |
Kind Code |
A1 |
Meissner, Frank ; et
al. |
August 30, 2001 |
Gas exchange valve control for internal combustion engines with an
electromagnetic actuator, equipped with gas springs
Abstract
A gas exchange valve control for internal combustion engines
includes an electromagnetic actuator equipped with gas springs. The
gas exchange valve control has an armature, which drives the gas
exchange valve and is arranged to oscillate between
stroke-separated switching magnets against the gas springs. The
armature serving as the separating piston between the gas springs
is moveable without friction in a closed armature stroke space. A
housing-like yoke, which encloses the armature stroke space,
including the adjacent switching magnets, exhibits between the
switching magnets a device which serves to shorten the respective
magnetic circuit of the respective switching magnet.
Inventors: |
Meissner, Frank; (Freising,
DE) ; Steffens, Hans-Joerg; (Bad Bramstedt,
DE) |
Correspondence
Address: |
Evenson, McKeown, Edwards & Lenahan, P.L.L.C.
Suite 700
1200 G Street, N.W.
Washington
DC
20005
US
|
Assignee: |
Bayerische Motoren Werke
Aktiengesellschaft.
|
Family ID: |
7632458 |
Appl. No.: |
09/778795 |
Filed: |
February 8, 2001 |
Current U.S.
Class: |
123/90.11 ;
123/90.65 |
Current CPC
Class: |
F01L 9/20 20210101; F01L
2301/00 20200501; F01L 1/465 20130101 |
Class at
Publication: |
123/90.11 ;
123/90.65 |
International
Class: |
F01L 009/04 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 25, 2000 |
DE |
100 08 991.7 |
Claims
What is claimed:
1. Gas exchange valve control assembly for internal combustion
engines with an electromagnetic actuator equipped with gas springs,
comprising: an armature drive-connected to a gas exchange valve,
and arranged to oscillate between stroke-separated switching
magnets against reset forces of gas springs, and gas springs, being
separated by the armature which serves as the separating piston,
said gas springs serving to adjust adapted spring characteristics
by gas metering valves and gas outlet valves which are controlled
as a function of load areas of an internal combustion engine, said
gas springs also serving to damp a stop of the armature on a
respective switching magnet, wherein the armature is designed so as
to separate the gas springs without any sliding seal, wherein, in a
respective holding position on a switching magnet, the armature
defines a damping chamber by means of an intercalated elastomeric
element, wherein each switching magnet exhibits a coil in a
laminated core which is centrosymmetrical relative to a guide shaft
of the armature of the gas exchange valve, wherein each core is
designed on an outer periphery flush with a coil, arranged in a
peripheral groove bordering the armature-sided face, so as to rest
planarly against a yoke which encloses the switching magnets
including an armature stroke space, and wherein said yoke carries
essentially in the center between the switching magnets a mechanism
which brings about an increased acceleration force at the armature
in the respective holding position.
2. Gas exchange valve control assembly as claimed in claim 1,
wherein the mechanism is part of the yoke, which is made of a
magnetizable material having low hysteresis and which encloses with
free passage to the armature an inwardly pointing projection on a
cylindrical switching magnet, wherein the projection with its free
inside peripheral area and flush adjoining, non-magnetizable cover
rings to both switching magnets defines the armature stroke space,
enclosing the gas springs, and wherein the inside peripheral area
serves as an inlet/outlet area of the magnetic lines in the
vicinity of the armature.
3. Gas exchange valve control assembly as claimed in claim 2,
wherein the wall thickness of the yoke, designed as a cylindrical
housing, is chosen as a segment of a magnetic circuit in accordance
with the magnetic line density in the centrosymmetrically laminated
cores, and wherein the projection exhibits a thickness, equivalent
to the yoke wall thickness.
4. Gas exchange valve control assembly as claimed in claim 2,
wherein the yoke is made of a ferromagnetic material, and wherein
cover rings, provided on both sides of the projection, are made of
a non-magnetizable light metal connection.
5. Gas exchange valve control assembly as claimed in claim 3,
wherein the yoke is made of a ferromagnetic material, and wherein
cover rings, provided on both sides of the projection, are made of
a non-magnetizable light metal connection.
6. Gas exchange valve control assembly as claimed in claim 1,
wherein each switching magnet is assigned a face plate on the coil
side, which faceplate is arranged gas tight in the housing-like
yoke, and wherein the faceplate carries the elastomeric element in
an armature-sided groove and forms with a concentric depression a
section of the damping chamber.
7. Gas exchange valve control assembly as claimed in claim 2,
wherein each switching magnet is assigned a face plate on the coil
side, which faceplate is arranged gas tight in the housing-like
yoke, and wherein the faceplate carries the elastomeric element in
an armature-sided groove and forms with a concentric depression a
section of the damping chamber.
8. Gas exchange valve control assembly as claimed in claim 3,
wherein each switching magnet is assigned a face plate on the coil
side, which faceplate is arranged gas tight in the housing-like
yoke, and p1 wherein the faceplate carries the elastomeric element
in an armature-sided groove and forms with a concentric depression
a section of the damping chamber.
9. Gas exchange valve control assembly as claimed in claim 4,
wherein each switching magnet is assigned a face plate on the coil
side, which faceplate is arranged gas tight in the housing-like
yoke, and wherein the faceplate carries the elastomeric element in
an armature-sided groove and forms with a concentric depression a
section of the damping chamber.
10. Gas exchange valve control assembly as claimed in claim 5,
wherein each switching magnet is assigned a face plate on the coil
side, which faceplate is arranged gas tight in the housing-like
yoke, and wherein the faceplate carries the elastomeric element in
an armature-sided groove and forms with a concentric depression a
section of the damping chamber.
11. An electromagnetic actuator for controlling movement of a gas
exchange valve of an internal combustion engine, comprising: an
armature connected to move with the gas exchange valve, a yoke
surrounding the armature, first and second switching magnets
disposed in the yoke and facing one another to form an armature
stroke space accommodating the armature, and gas springs in the
yoke and operable to adjust spring forces acting on the armature
during movement thereof, wherein the switching magnets are operable
to move the armature in the stroke space between respective holding
positions adjacent respective areas of the switching magnets,
elastomeric elements being provided between the armature and a
respective switching magnet to form a damping chamber between the
armature and respective switching magnet when in a holding
position, wherein the armature is configured to separate the gas
springs without any sliding seal, and wherein the yoke includes a
mechanism disposed between the switching magnets which effects an
increased acceleration force at the armature when in or near a
respective holding position.
12. An electromagnetic actuator according to claim 11, wherein the
first and second switching magnets are centrosymmetrical relative
to a guide shaft of the armature.
13. An electromagnetic actuator according to claim 12, wherein each
switching magnet exhibits a coil in a laminated core.
14. An electromagnetic actuator according to claim 13, wherein the
mechanism is part of the yoke, which is made of a magnetizable
material having low hysteresis and which encloses with free passage
to the armature an inwardly pointing projection on a cylindrical
switching magnet, wherein the projection with its free inside
peripheral area and flush adjoining, non-magnetizable cover rings
to both switching magnets defines the armature stroke space,
enclosing the gas springs, and wherein the inside peripheral area
serves as an inlet/outlet area of the magnetic lines in the
vicinity of the armature.
15. An electromagnetic actuator according to claim 14, wherein the
wall thickness of the yoke, designed as a cylindrical housing, is
chosen as a segment of a magnetic circuit in accordance with the
magnetic line density in the centrosymmetrically laminated cores,
and wherein the projection exhibits a thickness, equivalent to the
yoke wall thickness.
16. An electromagnetic actuator according to claim 15, wherein the
yoke is made of a ferromagnetic material, and wherein cover rings,
provided on both sides of the projection, are made of a
non-magnetizable light metal connection.
17. An electromagnetic actuator according to claim 16, wherein each
switching magnet is assigned a face plate on the coil side, which
faceplate is arranged gas tight in the housing-like yoke, and
wherein the faceplate carries the elastomeric element in an
armature-sided groove and forms with a concentric depression a
section of the damping chamber.
Description
[0001] This application claims the priority of German Patent
Application No. 100 08 991.7, filed in Germany, Feb. 25, 2000, the
disclosure of which is expressly incorporated by reference
herein.
BACKGROUND AND SUMMARY OF THE INVENTION
[0002] The invention relates to a gas exchange valve control for
internal combustion engines with an electromagnetic actuator,
equipped with gas springs. In this device an armature, which is
drive-connected to the gas exchange valve, is arranged so as to
oscillate between stroke-separated switching magnets against reset
forces of the gas springs. The gas springs, separated by the
armature, serving as the separating piston, serve to adjust the
adapted spring characteristics by the gas metering valves and gas
outlet valves, controlled as a function of the load areas of the
internal combustion engine. Furthermore, they serve to damp the
stop of the separating piston or the armature on the respective
switching magnet.
[0003] Such an armature is the object of the German patent
application P 100 03 116. Its goal is to achieve variably adapted
spring characteristics as a function of the load areas of the
internal combustion engine by means of a simple construction.
Furthermore, the goal is also to achieve a controlled damping of
the stop irrespective of the respective spring characteristic.
[0004] In this actuator the outer periphery of the armature,
serving as the separating piston between the two gas springs, is
equipped with a sliding seal, which is friction-connected to the
wall of the armature stroke space. Furthermore, the switching
magnets are not designed with respect to optimal magnetic line
flux.
[0005] The invention is based on the problem of improving this
class of actuator both with respect to its mechanical construction
and its electromagnetic design so that the cost of energy is
reduced and the armature is attracted with increased magnetic
force.
[0006] This problem is solved according to preferred embodiments of
the invention in that the armature is designed without any sliding
seal and separates the gas springs. In the respective holding
position on a switching magnet the armature defines a damping
chamber by means of an intercalated elastomeric element.
Furthermore, each switching element exhibits a coil in a core,
which is laminated centrosymmetrically relative to a guide shaft of
the armature or the gas exchange valve. Each core is designed on
the outer periphery flush with a coil, arranged in a peripheral
groove bordering the armature-sided face, so as to rest planarly
against a yoke, enclosing the switching magnets, including the
armature stroke space, and which carries essentially in the center
between the switching magnets a mechanism which brings about an
increased acceleration force at the armature in the respective
holding position.
[0007] A goal of the mechanical construction of the design of the
invention is to provide in the armature stroke space an armature
that separates the gas springs without friction owing to the
dispensing of a sliding ring seal and to which is assigned, to
achieve an air-damped stop, a damping chamber defined by an elastic
element. Since there is no armature friction, the cost of energy is
advantageously reduced. Furthermore, the damping chamber of the
invention achieves in another advantageous manner that the actuator
is acoustically improved.
[0008] With the electromagnetic design of the actuator according to
the invention, a shorter magnetic circuit for each switching magnet
is achieved. Thus, with the reduced magnetic circuit at least in
the starting phase of the acceleration of the armature from the
holding position on one of the switching magnets, the magnetic
resistance in the magnetic circuit is significantly reduced by just
an air slit. Thus, independently of the applied gas pressure at the
armature, the acceleration of said armature can be increased, a
feature that is advantageous in an advantageous manner in
particular to achieve high speeds of the internal combustion
engine. In connection with the shortened magnetic circuit of each
switching magnet, according to the invention, it is especially
advantageous that their cores be laminated centrosymmetrically in
order to reduce the leakage losses or to reduce the vortex losses,
as described and illustrated, for example, in the German Patent
Document DE 35 00 530 A1.
[0009] With the inventive combination of an improved mechanical
construction with an improved electromechanical design of a
pneumatic, electromagnetic actuator a gas exchange valve control
for internal combustion engines of high efficiency is achieved in
an advantageous manner. In this respect it is significantly simpler
with the electromagnetic potential of the invention to achieve a
load-dependent tuning of the pneumatic system.
[0010] Advantageous designs of the invention are described herein
and in the claims.
[0011] Other objects, advantages and novel features of the present
invention will become apparent from the following detailed
description of the invention when considered in conjunction with
the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a cross sectional view of an actuator assembly for
gas exchange control for internal combustion engines, constructed
according to a preferred embodiment of the invention, and
[0013] FIG. 2 is a top view of a switching magnet with a
centrosymmetrically laminated core taken along the line II-II in
FIG. 1.
DETAILED DESCRIPTION OF THE DISCLOSURE
[0014] A gas exchange valve control 1, which is not shown in
detail, for internal combustion engines (not illustrated) comprises
an actuator 2 with gas springs 3 and 4. An armature 6, which is
drive-connected to the gas exchange valve 5, is arranged so as to
oscillate between stroke-separated switching magnets 7 and 8
against reset forces of the gas springs 3 and 4. Furthermore, the
gas springs 3 and 4, which are separated by the armature 6, formed
as the separating piston, serve to determine adapted spring
characteristics by means of gas metering valves 9 and 9' and gas
outlet valves 10, 10', which are controlled as a function of the
load areas of the internal combustion engine. Said gas springs also
serve to damp the stop of the separating piston or the armature 6
on the respective switching magnet 7, 8.
[0015] To improve the actuator 2, according to the invention, both
in its mechanical construction and also in its electromagnetic
design, the invention proposes that the armature 6 be designed so
as to separate the gas springs 3, 4 without any sliding seal. In
the respective holding position on a switching magnet 7, 8 said
armature defines a damping chamber 12 by means of an intercalated
elastomeric element 11. Furthermore, each switching magnet 7, 8
exhibits a coil 13 in a laminated core 7', 8', which is
centrosymmetrical relative to a guide shaft 14 of the armature 6 or
the gas exchange valve 5. Each core 7', 8' is designed on the outer
periphery flush with a coil 13, arranged in a peripheral groove 16
bordering the armature-sided face 15, so as to rest planarly
against a yoke 18, which encloses the switching magnets 7 and 8,
including an armature stroke space 17, and which carries
essentially in the center between the switching magnets 7, 8 a
mechanism 19 which brings about an increased acceleration force at
the armature 6 in the respective holding position.
[0016] As evident from FIG. 1, the mechanism 19 is a yoke 18, which
is made of a magnetizable material having low hysteresis and which
encloses with free passage to the armature 6 an inwardly directed
projection 20 on a cylindrical switching magnet 7, 8. The
projection 20 with its free inside peripheral area 21 and flush
adjoining, non-magnetizable cover rings 22 to both switching
magnets 7, 8 defines the armature stroke space 17, enclosing the
gas springs 3, 4. The inside peripheral area 21 of the projection
20 serves as an inlet/outlet area of the magnet lines in the
vicinity of the armature. With the inventive projection 20 a
shortened magnetic circuit is achieved for each of the switching
magnets 7 and 8 with magnet lines that run only through an air gap
in the vicinity of the armature in the initial phase of armature
acceleration.
[0017] Furthermore, the wall thickness "s" of the yoke 18, designed
as a cylindrical housing, is chosen as a segment of a magnetic
circuit in accordance with the magnetic line density in the
centrosymmetrically laminated cores 7' and 8'. The projection 20
exhibits a thickness "d", which is equivalent to the yoke wall
thickness "s", or the inside peripheral area 21 of the projection
20 exhibits a height equivalent to the wall thickness "s". With
this design it is guaranteed that for the magnet lines in the yoke
18 and in the projection 20 the magnetic resistances due to the
change in cross section are avoided. To achieve a magnetic circuit
with low magnetic resistance the yoke 18 is made preferably of a
ferromagnetic material. Furthermore, the cover rings 22, provided
on both sides of the projection 20, are made of a non-magnetizable
light metal connection, in order to have the magnet lines, issuing
from the inside peripheral area 21 or entering into the same,
running bundled in the magnetic circuit.
[0018] As also apparent from FIG. 1, each switching magnet 7, 8 is
assigned on the coil side a face plate 23, which is arranged gas
tight in the housing-like yoke 18. Said face plate carries the
elastomeric element 11 in an armature-sided groove 24 and forms
with a concentric depression 25 a section of the damping chamber
12.
[0019] The foregoing disclosure has been set forth merely to
illustrate the invention and is not intended to be limiting. Since
modifications of the disclosed embodiments incorporating the spirit
and substance of the invention may occur to persons skilled in the
art, the invention should be construed to include everything within
the scope of the appended claims and equivalents thereof.
* * * * *