Information
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Patent Grant
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6318312
-
Patent Number
6,318,312
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Date Filed
Monday, June 12, 200024 years ago
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Date Issued
Tuesday, November 20, 200122 years ago
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Inventors
-
Original Assignees
-
Examiners
-
CPC
-
US Classifications
Field of Search
US
- 123 9011
- 123 4101
- 251 12901
- 251 1291
- 251 12915
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International Classifications
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Abstract
A method and device for cooling an electromagnetic actuator device of an internal combustion engine valves. A fluid stream circulating in the internal combustion engine, especially a lubricating oil stream, is passed through each electromagnetic actuator device to cool the actuator. The amount of the fluid stream passed through the actuator is variable and is adjusted by a suitable valve arrangement in such a way that a critical component temperature of the actuators is not exceeded. An electrical actuator parameter, such as the current flowing through the coils of the actuator, which corresponds to the component's temperature is determined in an electronic control unit associated with the actuators, and is compared in the electronic control unit with the critical component temperature or a corresponding critical electrical parameter. The electronic control unit controls the valve arrangement to provide the required stream of cooling fluid.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of priority based on German Application No. 19926412.0, filed Jun. 10, 1999, which is incorporated by reference herein in its entirety.
BACKGROUND OF THE INVENTION
The invention relates to a procedure for cooling electromagnetic actuating devices for internal combustion engine valves in which some of a fluid circulating in the internal combustion engine, particularly lubricating oil, is passed through each electromagnetic actuating device (i.e., an actuator).
An electromagnetic valve actuator for an internal combustion engine has immense advantages because of the freedom with respect to the valve control times, i.e., with respect to the pertinent opening and closing points of the valve. However, relatively high forces must be applied for actuation, especially for opening the valve, which necessitates a certain minimum coil and armature size. As a result, it is extremely difficult to accommodate a conventional actuator housing in a modern cylinder head of an internal combustion engine that, for example, drives a motor vehicle. Additionally, when the valves are actuated, a relatively large amount of heat develops in the coils, especially at higher actuation frequencies, which has to be dissipated in a suitable way.
Pure convection cooling of the actuator housing in the surrounding air is insufficient for this purpose, especially when the constricted space conditions just described are taken into account.
German Patent No. 197 14 496 A1 discloses a conventional electromagnetic valve actuator that is fluid cooled. In particular, a cooling channel is provided in an actuator housing through which some of the stream of fluid circulating inside the internal combustion engine is passed as a cooling fluid. This cooling fluid stream may be provided by engine coolant fluid (e.g., the liquid coolant of a liquid-cooled internal combustion engine) or may be derived from the lubricating oil stream of the internal combustion engine. Alternatively, as disclosed in U.S. Pat. No. 3,882,833, the cooling fluid stream may also be passed directly through the actuator, as opposed to passing through cooling channels integrated in an actuator housing.
A percentage of the power developed by the internal combustion engine is lost to circulating the cooling fluid to the actuators, a plurality of which are normally present in an internal combustion engine. This percentage is generally greater when the lubricating oil circulating in the internal combustion engine is used as the cooling fluid, and especially when the lubricating oil is cold and has a higher viscosity, i.e., before the internal combustion engine has warmed-up. It is desirable to keep power losses due to cooling fluid circulation as low as possible in order to minimize fuel consumption of the internal combustion engine.
SUMMARY OF THE INVENTION
The claimed invention is directed, at least in part, to reducing fuel consumption and engine power losses due to circulating cooling fluid. Accordingly, an adjustable valve arrangement varies the amount of cooling fluid passing through an actuator such that critical component temperatures of the actuator are not exceeded.
The claimed invention is also directed to a procedure for varying the amount of cooling fluid passing through an actuator. In addition to determining whether cooling of an actuator is necessary or not, the amount of cooling fluid passed through the actuator for cooling purposes may be adjusted in such a way that a critical (e.g., a maximum) actuator component temperature is not exceeded. This adjustment is performed by means of a suitable valve arrangement that allows a larger or smaller amount of cooling fluid to flow through the actuator as a function of the temperature of the actuator components.
The present invention provides a method of cooling an electromagnetic actuation device for a valve in an internal combustion engine. The method comprises providing a flow of cooling fluid through the electromagnetic actuation device; and varying the flow of cooling fluid such that a critical component temperature of the electromagnetic actuation device is not exceeded.
The present invention also provides an electromagnetic actuation device for a poppet valve in an internal combustion engine. The device comprises at least one coil winding; an electronic control unit electrically connected to the at least one coil winding; a fluid conduit thermally connected to the at least one coil winding; an adjustable fluid valve in fluid communication with the fluid conduit; and a driver mechanically connected to the fluid valve and electrically connected to the electronic control unit. The electronic control unit energizes the at least one coil winding to displace the poppet valve, the fluid conduit provides cooling fluid to dissipate heat generated by energizing the at least one coil winding, the fluid valve regulates cooling fluid flow through the fluid conduit, and the driver adjusts the fluid valve relative to the heat generated by energizing the at least one coil winding.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are incorporated herein and constitute part of this specification, illustrate presently preferred embodiments of the invention, and, together with the general description given above and the detailed description given below, serve to explain features of the invention.
FIG. 1
is a partial cross-section view of an actuator unit according to the present invention.
FIG. 2
is a schematic illustration of a system for controlling cooling fluid circulation.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
According to the claimed invention, the amount of cooling fluid that is passed through an actuator is only that which is actually needed to cool the actuator. If, for example, an internal combustion engine having a plurality of valve actuators is still cold, i.e., the internal combustion engine has not yet reached its operating temperature following a cold start, the actuators that are also still cold and do not need cooling. At least in theory, the cooling fluid streams through the actuators can be completely stopped and thereby eliminate engine power loss due to circulating cooling fluid through the actuators. However, when lubricating oil for the internal combustion engine is used as the cooling fluid, a small amount of lubricating oil is generally supplied to continue lubricating the actuators. Therefore, it may not be desirable to completely stop the supply of lubricating oil to the actuators.
Referring to
FIG. 1
, part of a cylinder head
11
is shown in which a combustion chamber
12
is isolated from a duct
13
by a poppet valve
14
. In particular, head
15
of valve
14
seats on a valve seat
16
to isolate the chamber
12
from the duct
13
. The head
15
is formed integrally with a stem
17
that slidably locates the valve in a valve guide
18
. A spring
22
biases the valve
14
to a closed position with respect to the head
11
, i.e., with the head
15
contiguously engaging the seat
16
.
An actuator
20
displaces the valve
14
between its open and closed positions. The actuator
20
includes a closing armature
27
and an opening armature
28
secured to the valve stem
17
. The valve stem
17
and the opening and closing armatures
27
,
28
are slidably disposed with respect to a solenoid body
29
, which is mounted by a valve body
30
to the cylinder head
11
. First and second ring seals
34
and
35
, respectively, are located between solenoid body
29
and the valve body
30
. The valve body
30
may include a base portion
30
a
, a central portion
30
b
, and a cap portion
30
c
. Opening armature
28
is biased with respect to cap portion
30
c
by an opening control spring
38
.
The solenoid body
29
has mounted within it an opening coil
41
and a closing coil
42
. These coils are electrically connected with an electronic control unit as will be described below.
Solenoid body
29
and valve body
30
define therebetween a generally annular volume
43
into which cooling fluid is fed by a supply line
44
and from which cooling fluid is withdrawn by discharge line
45
. This cooling fluid can be pressurized lubricating oil supplied by the engine, or can be coolant that is circulated through the cylinder head
11
.
Flow of the cooling fluid is regulated by a valve
50
that is operated by a driver
52
. As schematically shown in
FIG. 1
, valve
50
can include a butterfly plate
50
a
that is rotatable by a shaft
50
b
connected to the driver
52
. Rotating the shaft
50
b
causes the butterfly plate
50
a
to move between a first configuration, which significantly or completely limits flow of the cooling fluid through the supply line
44
, and a second configuration that minimally limits flow the cooling fluid through the supply line
44
. Of course, the valve
50
can be positioned in other locations, e.g., in the discharge line
45
, different types of valve mechanisms and drivers, e.g., a gate style valve driven by a solenoid, may be substituted.
The claimed invention is also directed to measuring a temperature of an actuator component by means of a suitable sensor and, based on the output of the sensor, determining (e.g., with an electronic control unit) whether the measured temperature is far below or near a critical maximum actuator component temperature. A larger or smaller amount of cooling fluid is then passed through the actuator based on this determination.
Referring to
FIG. 2
, an electronic control unit
60
can be electrically connected to the opening and closing coils
41
,
42
of the actuator
20
for actuating the valve
14
. The electronic control unit can also be electrically connected to the driver
52
for adjusting the valve
40
. A component temperature of the actuator
20
may be determined, approximately or virtually, in the electronic control unit associated with the actuator. This determination can be made using the electrical current flowing through the coil of the actuator, thereby eliminating the need for an independent temperature sensor. Specifically, when the electrical voltage applied across the coils
41
,
42
of the electromagnetic actuator
20
and the electrical current flowing through the coils
41
,
42
are known, the coil resistance, which itself depends significantly on the actuator temperature, can be determined according to well known principles. The magnitude of the electrical resistance of the coil thus represents the component temperature of the actuator and can consequently be compared with a corresponding maximum critical temperature (for the coil resistance).
Thus, generally expressed, an electrical actuator parameter corresponding to the present component temperature can be determined as a function of the electrical current flowing through the coils
41
,
42
of the actuator
20
. The electronic control unit
60
associated with the actuator
20
can compare the determined component temperature with the critical component temperature, or a critical electrical parameter corresponding to this temperature, whereupon the electrical control unit
60
controls the driver
52
to adjust the valve
50
, and thereby regulate the amount of cooling fluid required by the actuator
20
.
Of course, the electronic control unit
60
can be electrically connected to more than one actuator
20
and to more than one driver
52
.
While the present invention has been disclosed with reference to certain preferred embodiments, numerous modifications, alterations, and changes to the described embodiments are possible without departing from the sphere and scope of the present invention, as defined in the appended claims. Accordingly, it is intended that the present invention not be limited to the described embodiments, but that it have the full scope defined by the language of the following claims, and equivalents thereof.
Claims
- 1. A method of cooling an electromagnetic actuation device for a valve in an internal combustion engine, the method comprising:providing a flow of cooling fluid through the electromagnetic actuation device; and varying the flow of cooling fluid such that a critical component temperature of the electromagnetic actuation device is not exceeded.
- 2. The method according to claim 1, wherein the providing a flow of cooling fluid includes supplying lubricating oil from the internal combustion engine.
- 3. The method according to claim 1, wherein the providing a flow of cooling fluid includes supplying coolant from the internal combustion engine.
- 4. The method according to claim 1, wherein the varying the flow of cooling fluid includes providing a valve in the flow of cooling fluid.
- 5. The method according to claim 1, further comprising:measuring a temperature of a component of the electromagnetic actuation device; and comparing the measured temperature to a critical component temperature, and accordingly varying the flow of cooling fluid.
- 6. The method according to claim 5, wherein the measuring includes measuring an electrical parameter of the electromagnetic actuation device that corresponds to a temperature of a component of the electromagnetic actuation device, and the comparing includes comparing the electrical parameter to a critical electrical parameter corresponding to a critical component temperature.
- 7. The method according to claim 6, wherein the measuring an electrical parameter includes measuring current flow through the electromagnetic actuation device.
- 8. The method according to claim 7, wherein the providing a flow of cooling fluid includes supplying lubricating oil from the internal combustion engine, and the varying the flow of cooling fluid includes providing a valve in the flow of lubricating oil.
- 9. An electromagnetic actuation device for a poppet valve in an internal combustion engine, the device comprising:at least one coil winding; an electronic control unit electrically connected to the at least one coil winding, the electronic control unit adapted for energizing the at least one coil winding to displace the poppet valve; a fluid conduit thermally connected to the at least one coil winding, the fluid conduit adapted for providing cooling fluid to dissipate heat generated by energizing the at least one coil winding; an adjustable fluid valve in fluid communication with the fluid conduit, the fluid valve adapted for regulating cooling fluid flow through the fluid conduit; and a driver mechanically connected to the fluid valve and electrically connected to the electronic control unit, the driver adjusting the fluid valve relative to the heat generated by energizing the at least one coil winding.
- 10. The device according to claim 9, wherein the fluid valve is in fluid communication with a supply of lubricating oil for the internal combustion engine.
- 11. The device according to claim 9, wherein the fluid valve is in fluid communication with a supply of coolant for the internal combustion engine.
- 12. The device according to claim 9, further comprising:a temperature sensor electrically connected to the electronic control unit, the temperature sensor measuring the heat generated by energizing the at least one coil winding.
- 13. The device according to claim 12, wherein the temperature sensor measures electrical resistance of the at least one coil winding, the electronic control unit correlates the measured electrical resistance to the heat generated by energizing the at least one coil winding, and the electronic control unit signals the driver to adjust the fluid valve so that a winding temperature due to the heat generated by energizing the at least one coil winding is less than a critical temperature.
- 14. The device according to claim 13, wherein the fluid valve is in fluid communication with a supply of lubricating oil for the internal combustion engine.
Priority Claims (1)
Number |
Date |
Country |
Kind |
199 26 412 |
Jun 1999 |
DE |
|
US Referenced Citations (3)
Number |
Name |
Date |
Kind |
3882833 |
Longstaff et al. |
May 1975 |
|
5875746 |
Izuo |
Mar 1999 |
|
6089196 |
Izuo et al. |
Jul 2000 |
|
Foreign Referenced Citations (1)
Number |
Date |
Country |
197 14 496 A 1 |
Oct 1998 |
DE |