U.S. patent application number 11/702444 was filed with the patent office on 2007-07-12 for apparatus for adjusting a camshaft, and method for operating an apparatus for adjusting a camshaft.
Invention is credited to Alexander von Gaisberg-Helfenberg, Matthias Gregor, Jens Meintschel, Thomas Stolk.
Application Number | 20070157897 11/702444 |
Document ID | / |
Family ID | 35094570 |
Filed Date | 2007-07-12 |
United States Patent
Application |
20070157897 |
Kind Code |
A1 |
Gregor; Matthias ; et
al. |
July 12, 2007 |
Apparatus for adjusting a camshaft, and method for operating an
apparatus for adjusting a camshaft
Abstract
In an apparatus for adjusting a phase position of a camshaft in
relation to a crankshaft which drives the camshaft, including an
electric actuator for operating an adjustment mechanism, which can
move the camshaft to a basic or emergency-operating position in the
event of a shut-down as a result of an operational fault, the
emergency-operating position can be reliably reached with the aid
of the electric actuator which is supplied with energy by an energy
supply that is separate from an operational energy supply and which
is capable of moving the adjustment mechanism to the
emergency-operating position. Also, a method for operating an
apparatus for adjusting a phase position of a camshaft is
provided.
Inventors: |
Gregor; Matthias;
(Stuttgart, DE) ; Meintschel; Jens; (Esslingen,
DE) ; Stolk; Thomas; (Kirchheim, DE) ;
Gaisberg-Helfenberg; Alexander von; (Beilstein, DE) |
Correspondence
Address: |
KLAUS J. BACH
4407 TWIN OAKS DRIVE
MURRYSVILLE
PA
15668
US
|
Family ID: |
35094570 |
Appl. No.: |
11/702444 |
Filed: |
February 5, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/EP05/08449 |
Aug 4, 2005 |
|
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11702444 |
Feb 5, 2007 |
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Current U.S.
Class: |
123/90.17 ;
123/90.15 |
Current CPC
Class: |
F01L 1/3442 20130101;
F01L 2001/34453 20130101; F01L 2820/01 20130101; F01L 1/352
20130101; F01L 1/34 20130101 |
Class at
Publication: |
123/090.17 ;
123/090.15 |
International
Class: |
F01L 1/34 20060101
F01L001/34 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 6, 2004 |
DE |
10 2004 038 171.2 |
Claims
1. An apparatus for adjusting a phase position of a camshaft (12)
in relation to a crankshaft which drives the camshaft (12), said
apparatus including an adjustment mechanism for adjusting the phase
position of the camshaft relative to the camshaft, an actuator (15)
for operating the adjustment mechanism (11), the camshaft (12)
being movable to an emergency-operating position in the event of a
shut-down as a result of an operational fault, and an energy supply
(19, 22) separate from an operating energy supply provided for the
actuator (15) for supplying energy thereto for moving the
adjustment mechanism (11) to the emergency-operating position.
2. The apparatus as claimed in claim 1, wherein the separate energy
supply (19, 22) comprises an energy store (19), by which the
actuator (15) can be supplied with energy for a brief period of
time.
3. The apparatus as claimed in claim 1, wherein the separate energy
supply (19, 22) is activatable by an engine controller (23).
4. The apparatus as claimed in claim 1, wherein the energy supply
(19) comprises a storage battery.
5. The apparatus as claimed in claim 1, wherein the energy supply
(19) comprises a capacitor.
6. The apparatus as claimed in claim 1, wherein the separate energy
supply (19, 22) comprises a connection (22) to an on-board vehicle
electrical system (16), which connection is independent of the
operating supply.
7. The apparatus as claimed in claim 1, wherein the adjustment
mechanism (11) is designed such that it automatically moves to a
first end stop position when the actuator (15) is in the
de-energized state.
8. The apparatus as claimed in claim 1, wherein the actuator (15)
is in the form of an electric brake.
9. The apparatus as claimed in claim 1, wherein the actuator (15)
is in the form of a hysteresis brake.
10. The apparatus as claimed in claim 9, wherein the hysteresis
brake has a separate auxiliary coil (27) which is actuatable in the
event of an operational fault in a field coil (26) of the
hysteresis brake.
11. A method for operating an apparatus for adjusting a phase
position of a camshaft (12) in relation to a crankshaft which
drives the camshaft (12), the apparatus including an electric
actuator (15) for operating an adjustment mechanism (11), with the
camshaft (12) being movable to an emergency-operating position in
the event of a shut-down as a result of an operational fault, said
method comprising the steps of supplying the actuator (15) with
energy from an energy supply (19, 22) which is separate from its
normal operating energy supply for moving the adjustment mechanism
(11) to the emergency-operating position.
12. The method as claimed in claim 11, wherein, in the de-energized
state, the adjustment mechanism (11) automatically moves to a first
end stop position.
13. The method as claimed in claim 11, wherein the adjustment
mechanism (11) is moved in the direction toward a second end stop
position by the actuator (15) which can be supplied with power by
the separate energy supply (19, 22), for reaching a locking
position in which the adjustment mechanism (11) is then locked.
14. The method as claimed in claim 13, wherein the adjustment
mechanism (11) is firmly engaged in the locked position.
Description
[0001] This is a Continuation-In-Part Application of pending
International patent application PCT/EP2005/008449 filed Aug. 4,
2005 and claiming the priority of German patent application 10 2004
038 171.2 filed Aug. 6, 2004.
BACKGROUND OF THE INVENTION
[0002] The invention relates to an apparatus for adjusting the
phase position of a camshaft relative to a crankshaft driving the
camshaft, and to a method of operating an apparatus for adjusting a
camshaft.
[0003] It is known to change the phase position of a camshaft of an
internal when the engine is turned off, combustion engine using
adjusting devices. Normally, the camshaft is moved to a particular
basic position and fixed in this position. In the case of electric
adjusting devices, a separately energized electric adjuster or an
electric adjuster with permanent-magnet excitation, for example, is
used for this purpose, whereas a hydraulic rotary piston adjuster
which has a locking unit is used in the case of hydraulic adjusting
devices. The locking unit fixes the hydraulic adjuster in its basic
position until a sufficiently high oil pressure for adjusting the
camshaft has built up after star-up of the internal combustion
engine.
[0004] When the internal combustion engine stalls, it is not
possible to adjust the hydraulic adjuster in a controlled manner,
with the result that the camshaft may be in an undefined position
outside the basic position. When the vehicle is next started, the
camshaft must therefore be moved to a suitable basic position, for
example by a compensation spring. In the case of electric
adjusters, no additional measure is required when restarting
following stalling of the internal combustion engine since the
adjuster can move the camshaft to the respective basic position
even when the internal combustion engine is shut down or during
startup operations. However, in the case of electric adjusting
devices, the adjuster and/or its controller may fail and thus not
reach the basic or emergency-operation position which is required
for at least restricted operation so that, as a result, the engine
cannot be started. By way of example, adjusting devices with
restoring springs which allow an emergency-operation position to be
reached, but which involve increased power consumption and
unattractive system dynamics and also require a relatively large
installation space, are known.
[0005] DE 102 57 706 A1 discloses an adjusting device for a
camshaft, wherein the camshaft is adjusted in the direction of an
early or late basic or emergency-operation position by simply
braking the adjusting shaft if the adjuster or its power supply
fails while the adjustment mechanism is rotating.
[0006] It is the principle object of the present invention to
provide an adjusting device for a camshaft, in which adjusting
device a basic or emergency-operating position can be reliably
reached in the event of an operational fault. It also is an object
to provide a method for operating such an device.
SUMMARY OF THE INVENTION
[0007] In an apparatus for adjusting a phase position of a camshaft
in relation to a crankshaft which drives the camshaft, including an
electric actuator for operating an adjustment mechanism, which can
move the camshaft to a basic or emergency-operating position in the
event of a shut-down as a result of an operational fault, the
emergency-operating position can be reliably reached with the aid
of the electric actuator which is supplied with energy by an energy
supply that is separate from an operational energy supply and which
is capable of moving the adjustment mechanism to the
emergency-operating position. Also, a method for operating an
apparatus for adjusting a phase position of a camshaft is
provided.
[0008] An inventive apparatus for adjusting a phase position of a
camshaft in relation to a crankshaft which drives the camshaft has
an actuator which can be supplied with energy by an energy supply
which is separate from its operating supply in order to move the
adjustment mechanism to the basic or emergency-operating position.
As a result, the actuator can be supplied with operating power by a
second supply system which is independent of an operating supply of
the apparatus for a brief period of time in the event of an
operational fault, which is highly cost-effective and operationally
reliable. Furthermore, the basic or emergency-operation position
can also be advantageously assumed in the event of normal shut-down
of the internal combustion engine.
[0009] If the separate energy supply comprises an energy store, by
means of which the actuator can be supplied with energy, the
actuator can move the adjustment mechanism to a desired position in
a targeted manner in the event of an operational fault. The energy
store is preferably an electrical storage means for an electrically
operable actuator. However, other energy stores for other types of
actuator and kinds of adjusting apparatuses, for example a
hydraulic storage means for a hydraulic adjusting apparatus, are
also conceivable.
[0010] The separate energy supply can expediently be activated by
an engine controller which actuates the internal combustion engine.
If an operational fault is identified, the engine controller can
quickly operate the energy supply in order to provide power for
activating the actuator.
[0011] In one favorable embodiment, the energy store comprises a
storage battery. As an alternative, or in addition, the energy
store may comprise a particularly preferred capacitor. Said
capacitor is particularly highly suited to rapid discharging. If
necessary, the actuator can be supplied with current from the
capacitor of a brief period, for a few hundred milliseconds, for
example typically 200 ms, in order to move the adjustment mechanism
to a desired position. The basic or emergency-operation position
can be reached at the latest after approximately 300 ms. The basic
or emergency-operation position preferably corresponds to a locked
position, with the adjustment mechanism crossing a locking unit
when the actuator drives the adjustment mechanism. The energy store
is advantageously of small design since only a low power content is
required for such a brief operation. This is advantageous, for
example, for feeding the content of the storage means to a
hysteresis brake for a brief period of time, and in this way moving
the camshaft to its basic or emergency operating position.
[0012] In a favorable refinement, the separate energy supply
comprises a separate connection to an on-board vehicle electrical
system, which connection is separate from the normal operating
energy supply for the actuator. The separate energy supply is
expediently accessible with a certain safety level in the engine
controller.
[0013] It is particularly favorable when the adjusting device is
designed such that it automatically moves to a defined end stop
position when it or the actuator is de-energized.
[0014] In one particularly preferred refinement, the actuator is in
the form of a hysteresis brake. The actuator preferably has a
separate auxiliary coil which can be actuated in the event of an
operational fault in the field coil of the actuator. In this case,
in spite of a defective field coil, a magnetic field can still be
built up in the hysteresis brake in order to brake the adjustment
mechanism. The auxiliary coil expediently has a high impedance that
is it has as many turns as possible, these turns being wound around
a stator of the actuator. The auxiliary coil is expediently
supplied with power by the energy store, which is independent of
the operating energy supply. Although the provision of as many
turns as possible increases the electrical time constant of the
auxiliary coil, which also results in a reduction in power
consumption, and this is advantageous in terms of the size of the
energy store.
[0015] According to the inventive method for operating an apparatus
for adjusting a phase position of a camshaft, an actuator which
operates an adjustment mechanism is supplied with energy by an
energy supply which is separate from the operating supply in order
to move the adjustment mechanism to a basic or emergency-operation
position.
[0016] If the adjustment mechanism automatically moves to a
defined, first end stop position in the de-energized state, a
locking device, which determines the basic or emergency-operating
position, can be reliably reached or crossed as a result of a
movement of the adjustment mechanism toward a second end stop
position which is provided by the actuator supplied by the separate
energy supply. If the adjustment mechanism was already on the other
side of this locking device in terms of the direction of rotation,
the adjustment mechanism automatically returns to the defined first
end stop position after the energy store has been emptied and, with
a brief delay, then reaches the locking device, is locked there and
is thus in its basic and emergency-operation position.
[0017] The adjustment mechanism is expediently retained in the
locking position; in particular, the adjustment mechanism is
latched in place in the locked position.
[0018] An exemplary embodiment of the invention will be described
below in greater detail with reference to the accompanying
drawing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 shows schematically a preferred apparatus for
adjusting a camshaft, having an energy store; and
[0020] FIG. 2 shows schematically a preferred apparatus for
adjusting a camshaft, having a separate connection to an on-board
vehicle electrical system.
DESCRIPTION OF PARTICULAR EMBODIMENTS
[0021] As can be seen from FIG. 1, a particularly preferred
apparatus 10 for adjusting a phase position of a camshaft 12 in
relation to a crankshaft (not illustrated) which drives the
camshaft 12 comprises an actuator 15, which is in the form of a
hysteresis brake, for operating an adjustment mechanism 11. The
adjustment mechanism 11 can be driven by a drive 13 which is in the
form of a drive wheel and is connected to the crankshaft, for
example, via a drive chain. The drive 13 surrounds the adjustment
mechanism 11 in a concentric manner. The actuator 15, which is in
the form of an electrically operable actuator, in particular in the
form of a hysteresis brake, is operatively connected to an
actuating input 14 to the adjustment mechanism 11. An axis of
rotation of the actuator 15 is indicated as a dash-dotted line. The
adjustment mechanism 11 may, for example, be a planetary gear
mechanism, a wobble gear mechanism or an eccentric gear mechanism.
The actuator 15, which is in the form of a hysteresis brake,
comprises a field coil 26 which provides a holding torque or a
drive torque for holding or adjusting the adjustment mechanism 11
during energization.
[0022] During normal operation, the field coil 26 is supplied with
energy by a customary on-board vehicle electrical system 16, and
this is schematically indicated by supply lines 17 and 18. An
engine controller 23 is also provided, which engine controller is
connected to the on-board vehicle electrical system 16. This is
indicated by a double-headed arrow 24 between the on-board vehicle
electrical system 16 and the engine controller 23.
[0023] In order to move the actuator 15 to its basic or
emergency-operating position, a separate energy supply is provided
consistent of a separate energy store 19 which can be actuated by
the engine controller 23. The connection between the engine
controller 23 and the energy store 19 is indicated by a
double-headed arrow 25. In order to quickly operate the actuator 15
in the event of an operational fault, the energy store 19 comprises
a storage battery and/or preferably a capacitor. Supply lines 20,
21 are provided between the energy store 19 and the actuator 15 in
order to supply the actuator 15 with electrical energy as
required.
[0024] The adjustment mechanism 11 is designed such that it
automatically moves to a defined first end stop when the hysteresis
brake is in the de-energized state. In the event of a fault, the
actuator 15, which operates the adjustment mechanism 11, is
supplied with current from the energy store 19, which is preferably
a capacitor, for a brief period of approximately 200 ms, so as to
move in the direction toward another, second end stop. In the
process, a locking device is passed, which locking device can latch
the adjustment mechanism 11 in place and thus fix the adjustment
mechanism 11 in its basic or emergency-operating position. If the
adjustment mechanism 11 was already on the other side of the
locking device, it automatically moves, after the capacitor is
drained and depending on its design, in the direction toward the
defined first end stop and reaches the locking position from the
other side. The locking position is therefore reliably reached,
independently of the actual position of the adjustment mechanism.
The adjustment mechanism 11 reaches its basic or
emergency-operating position after a brief time, for example at the
latest after 300 ms, following a power loss.
[0025] FIG. 2 shows an alternative embodiment. Identical elements
are designated by the same reference symbols as in FIG. 1. The
design corresponds to that of FIG. 1, to which reference is made
for explanatory purposes. Instead of an energy store 19 (FIG. 1),
the separate energy supply provided is now a connection 22 to an
on-board vehicle electrical system 16', which connection is
separate from the normal operating power supply. In this case, an
actuator 15, which is in the form of a hysteresis brake, has a
separate auxiliary coil 27 which can be actuated by an engine
controller 23 in the event of an operational fault in a field coil
26 of the actuator 15, and this is indicated by arrows 24 between
the engine controller 23 and the on-board vehicle electrical system
16.
[0026] The auxiliary coil 27 has a high impedance in order to still
build up a magnetic field in the hysteresis brake with a relatively
low power requirement in the event of a defect in a field coil 26
of the hysteresis brake. The auxiliary coil 27 is wound around a
stator of the hysteresis brake.
* * * * *