U.S. patent application number 15/410742 was filed with the patent office on 2017-07-20 for metallic hollow valve for an internal combustion engine of a utility motor vehicle.
The applicant listed for this patent is Mahle International GmbH. Invention is credited to Peter Kroos, Christoph Luven, Alexander Puck, Roland Schacherer.
Application Number | 20170204752 15/410742 |
Document ID | / |
Family ID | 57838287 |
Filed Date | 2017-07-20 |
United States Patent
Application |
20170204752 |
Kind Code |
A1 |
Kroos; Peter ; et
al. |
July 20, 2017 |
METALLIC HOLLOW VALVE FOR AN INTERNAL COMBUSTION ENGINE OF A
UTILITY MOTOR VEHICLE
Abstract
A metallic hollow valve for an internal combustion engine of a
utility vehicle may include a tubular valve stem and a valve head
merging into the valve stem. The valve head may have an outer
diameter that is enlarged compared to the valve stem. The valve
stem and the valve head may together delimit a hollow space. The
valve stem may have an outer diameter of more than 7 mm, for
example between 8 mm and 11 mm. The valve stem may have an inner
diameter of at least 4.5 mm, for example between 5 mm and 7 mm.
Inventors: |
Kroos; Peter; (Rutesheim,
DE) ; Luven; Christoph; (Stuttgart, DE) ;
Puck; Alexander; (Esslingen, DE) ; Schacherer;
Roland; (Geisingen, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Mahle International GmbH |
Stuttgart |
|
DE |
|
|
Family ID: |
57838287 |
Appl. No.: |
15/410742 |
Filed: |
January 19, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F01L 3/14 20130101; F01L
2301/00 20200501; F01L 2303/00 20200501; F01L 3/04 20130101; F01L
3/20 20130101; F01L 3/06 20130101 |
International
Class: |
F01L 3/14 20060101
F01L003/14; F01L 3/06 20060101 F01L003/06; F01L 3/20 20060101
F01L003/20 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 20, 2016 |
DE |
10 2016 200 739.4 |
Claims
1. A metallic hollow valve for an internal combustion engine of a
utility vehicle, comprising: a tubular valve stem and a valve head
merging into the valve stem, the valve head having an outer
diameter that is enlarged compared to the valve stem; the valve
stem and the valve head together delimiting a hollow space; wherein
the valve stem has an outer diameter of more than 7 mm; and wherein
the valve stem has an inner diameter of at least 4.5 mm.
2. The metallic hollow valve according to claim 1, wherein the
valve head includes a head base facing away from the valve stem,
and wherein the head base has a base thickness between 2 mm and 5
mm.
3. The metallic hollow valve according to claim 1, wherein the
valve stem has a wall thickness between 1.5 mm and 5 mm.
4. The metallic hollow valve according to claim 1, further
comprising a valve neck arranged between valve stem and valve head,
wherein the valve neck has a wall thickness between 1.5 mm and 5
mm.
5. The metallic hollow valve according to claim 1, wherein the
valve head is at least one of forged and electrochemically
machined.
6. The metallic hollow valve according to claim 1, wherein the
hollow space is at least partly filled with a fluid.
7. An internal combustion engine for a utility vehicle, comprising:
at least one cylinder including a combustion chamber having an air
inlet and an exhaust outlet; a valve drive including a metallic
hollow valve for opening and closing at least one of the air inlet
and the exhaust outlet, the metallic hollow valve including: a
tubular valve stem and a valve head merging into the valve stem;
the valve stem and the valve head together delimiting a hollow
space; the valve stem having an outer diameter of between 7 mm and
11 mm and an inner diameter of between 4.5 mm and 7 mm; and wherein
the valve head has an outer diameter that is enlarged compared to
the outer diameter of the valve stem.
8. The internal combustion engine according to claim 7, further
comprising a valve seat surrounding at least one of the air inlet
and the exhaust outlet, wherein the metallic hollow valve engages
via a contact section against the valve seat in a closed position,
in which the metallic hollow valve closes at least one of the air
inlet and the exhaust outlet; and wherein the metallic hollow valve
is hard-faced at least in a region of the contact section.
9. The internal combustion engine according to claim 8, wherein the
metallic hollow valve is hard-faced via at least one of a plasma
powder deposit welded Iron filler material and a plasma powder
deposit welded Cobalt filler material.
10. A utility vehicle, comprising: an internal combustion engine
including: at least one cylinder including a combustion chamber
having an air inlet and an exhaust outlet; a valve drive including
a metallic hollow valve for opening and closing at least one of the
air inlet and the exhaust outlet, the metallic hollow valve
including: a tubular valve stem and a valve head merging into the
valve stem; the valve stem and the valve head together delimiting a
hollow space; the valve stem having an outer diameter of between 8
mm and 11 mm, an inner diameter of between 5 mm and 7 mm, and a
wall thickness of between 1.5 mm and 5 mm; and wherein the valve
head has an outer diameter that is enlarged compared to the outer
diameter of the valve stem.
11. The utility vehicle according to claim 10, wherein the valve
head has at least one of a hard-faced iron material deposit and a
hard-faced cobalt material deposit.
12. The utility vehicle according to claim 10, wherein the internal
combustion engine further includes a valve seat surrounding at
least one of the air inlet and the exhaust outlet, wherein the
metallic hollow valve engages via a contact section against the
valve seat in a closed position, in which the metallic hollow valve
closes the at least one of the air inlet and the exhaust outlet;
and wherein the metallic hollow valve includes at least one of a
hard-faced iron material deposit and a hard-faced cobalt material
deposit disposed at least in a region of the contact section.
13. The utility vehicle according to claim 10, wherein at least one
of: the valve head includes a head base facing away from the valve
stem, and wherein the head base has a base thickness between 2 mm
and 5 mm; and the valve stem has a wall thickness between 1.5 mm
and 5 mm.
14. The utility vehicle according to claim 10, wherein the metallic
hollow valve further includes a valve neck arranged between valve
stem and valve head, wherein the valve neck has a wall thickness
between 1.5 mm and 5 mm.
15. The internal combustion engine according to claim 7, wherein
the valve head includes a head base facing away from the valve
stem, and wherein the head base has a base thickness between 2 mm
and 5 mm.
16. The internal combustion engine according to claim 7, wherein
the valve stem has a wall thickness between 1.5 mm and 5 mm.
17. The internal combustion engine according to claim 7, wherein
the metallic hollow valve further includes a valve neck arranged
between valve stem and valve head, wherein the valve neck has a
wall thickness between 1.5 mm and 5 mm.
18. The metallic hollow valve according to claim 1, wherein the
valve head includes at least one of a hard-faced iron material
deposit and a hard-faced cobalt material deposit.
19. The metallic hollow valve according to claim 1, wherein the
outer diameter of the valve stem is between 8 mm and 11 mm.
20. The metallic hollow valve according to claim 1, wherein the
inner diameter of the valve stem is between 5 mm and 7 mm.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to German Patent
Application DE 10 2016 200 739.4, filed Jan. 20, 2016, the contents
of which is hereby incorporated by reference in its entirety.
TECHNICAL FIELD
[0002] The invention relates to a metallic hollow valve for an
internal combustion engine of a utility vehicle. The invention,
furthermore, relates to an internal combustion engine of a utility
vehicle with such a metallic hollow valve. The invention also
relates to a utility vehicle with such an internal combustion
engine.
BACKGROUND
[0003] Increasing thermal loads in internal combustion engines of
utility vehicles make it increasingly necessary to cool central
components such as valves for opening and closing air inlets and
exhaust outlets of the internal combustion engine of these
vehicles. From the passenger car sector it is known to design said
valves as so-called metallic hollow valves which comprise a liquid
cooling medium located inside. It is generally true for metallic
hollow valves that these have a lower own weight than solid valves
and because of said filling with a cooling medium allow an improved
heat dissipation.
[0004] Since the requirements made on said valves in the utility
vehicle sector with respect to wear resistance and lifespan are
significantly higher than in the passenger car sector and could not
be achieved to date by conventional hollow valves, conventional
hollow valves are not employed in utility vehicles to date.
SUMMARY
[0005] It is therefore an object of the present invention to create
an improved embodiment for a metallic hollow valve which is also
suitable in particular with respect to wear characteristics and
lifespan for use in utility vehicles.
[0006] According to the invention, this object is solved through
the subject of the independent claim(s). Advantageous embodiments
are subject of the dependent claims.
[0007] A metallic hollow valve according to the invention for an
internal combustion engine of a utility vehicle comprises a tubular
valve stem, which merges into a valve head with an outer diameter
that is enlarged with respect to the valve stem. Here, "metallic"
is to mean that the material both of the valve stem and also of the
valve head is or comprises a metal. The valve steam and the valve
head according to the invention comprise a common hollow space.
Said hollow space can be filled with a cooling medium in order to
decisively improve the heat dissipation from the hollow valve.
Experimental tests have now surprisingly shown that a metallic
hollow valve is also capable of fulfilling the requirements that
exist with respect to wear resistance and expected lifespan in a
utility vehicle, when the valve stem has an outer diameter of more
than 7 mm and an inner diameter delimiting the hollow space of at
least 4.5 mm. Said dimensions of the valve stem which are
substantial for the invention result in that by means of the
cooling medium present in the hollow space heat can be particularly
effectively dissipated from the hollow valve and evenly
distributed.
[0008] To achieve a particularly high wear resistance and a
particularly long lifespan, the valve stem can particularly
preferably have an outer diameter between 8 mm and 11 mm.
Alternatively or additionally, the valve stem can have an inner
diameter between 5 mm and 7 mm.
[0009] In an advantageous further development, the valve head
comprises a head base facing away from the valve stem, which has a
base thickness between 2 mm and 4 mm. Such a delicate, i.e.
comparatively thin-walled configuration of the base thickness
results in a particularly even thermal coupling of the hollow valve
to the combustion chamber of the internal combustion engine, in
which the hollow valve is employed as part of a valve drive. In
particular, the formation of undesirable cracks due to uneven
heating of the hollow valve in the region of the head base can be
counteracted by means of this measure.
[0010] In order to be able to achieve as efficient as possible a
cooling of the metallic hollow valve, a wall thickness of the valve
stem is designed delicate, i.e. comparatively thin-walled. With
this version, the wall thickness of the valve stem therefore is
between 1.5 mm and 5 mm.
[0011] In order to be able to achieve the desired cooling of the
metallic hollow valve that is as efficient as possible, a wall
thickness of the hollow valve in the region between valve stem and
valve head, i.e. in the region of the so-called valve neck, can
also be designed delicately. Particularly preferably, said wall
thickness of the valve neck amounts to between 1.5 mm and 5 mm.
[0012] In a further preferred embodiment, the valve head is
produced by means of forging or by means of electrochemical
machining. In this way, a high wear resistance of the valve head
which is exposed to particularly high thermal loads can be
achieved.
[0013] In a preferred embodiment, the hollow space is partly filled
with a fluid, preferentially with sodium. This allows a
particularly effective dissipation of the heat from the combustion
chamber of the internal combustion engine absorbed by the hollow
valve in the region of the valve head.
[0014] The invention, furthermore, relates to an internal
combustion engine for a utility vehicle with at least one cylinder,
which comprises a combustion chamber. On the combustion chamber, an
air inlet and an exhaust outlet are provided. The internal
combustion engine, furthermore, comprises a valve drive which for
opening and closing the air inlet and/or the exhaust outlet
comprises a metallic hollow valve introduced above. The advantages
of the metallic hollow valve explained above are therefore
transferred to the internal combustion engine according to the
invention.
[0015] In a preferred embodiment of the internal combustion engine
according to the invention, the air inlet and/or the exhaust outlet
are surrounded by a valve seat, against which the hollow valve in a
closing position lies with a contact section. In the closing
position, the hollow valve closes the air inlet and the exhaust
outlet respectively. The hollow valve is hard-faced at least in the
region of the contact section. This measure results in an improved
wear resistance of the hollow valve.
[0016] Preferably, the hard facing of the contact section can be
produced by means of plasma powder deposit welding, particularly
preferably using iron (Fe) or Cobalt (Co) as filler material. A
hard facing produced in this way has a particularly long
lifespan.
[0017] The invention furthermore relates to a utility vehicle with
an internal combustion engine introduced above. The advantages of
the internal combustion engine according to the invention mentioned
above are therefore also transferred to the utility vehicle
according to the invention.
[0018] Further important features and advantages of the invention
are obtained from the subclaims, from the drawing and from the
associated FIGURE description by way of the drawing.
[0019] It is to be understood that the features mentioned above and
still to be explained in the following cannot only be used in the
respective combination stated but also in other combinations or by
themselves without leaving the scope of the present invention.
[0020] Preferred exemplary embodiments of the invention are shown
in the drawing and are explained in more detail in the following
description, wherein same reference characters relate to same or
similar or functionally same components.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The FIGURE shows a cross-sectional view of an exemplary
metallic hollow valve according to the disclosure.
DETAILED DESCRIPTION
[0022] The only FIGURE shows an example of a metallic hollow valve
1 according to the invention in a longitudinal section along a
centre longitudinal axis M of the valve stem 2 of the hollow valve.
By way of the centre longitudinal axis M, an axial direction A is
defined. Along the axial direction A, the valve stem 2 merges into
a valve head 3, which compared with the valve stem 2 has an
enlarged outer diameter d.sub.A. The valve stem 2 and the valve
head 3 are integrally moulded onto one another. The valve head 3
can be produced by means of forging or by means of electrochemical
machining.
[0023] As is evident from the FIGURE, the valve steam 2 and the
valve head 3--known also as valve disc to the person skilled in the
art--have a common hollow space 4. This hollow space 4 is partly
filled with a fluid, preferentially with sodium, which for the sake
of clarity is not shown in the FIGURE. The valve stem 2 has an
outer diameter d.sub.A of more than 7 mm. Preferably, the value for
the outer diameter d.sub.A is between 8 mm and 11 mm. Furthermore,
the valve stem has an inner diameter d.sub.I of at least 4.5 mm.
Preferably, the value for the inner diameter d.sub.I is between 5
mm and 7 mm. Particularly preferably, the valve stem has a wall
thickness d between 1.5 mm and 5 mm. Here, said wall thickness d is
defined by the difference between the outer diameter d.sub.A and
the inner diameter d.sub.I.
[0024] As is further evident from the representation of the FIGURE,
the valve head 3 has a head base 5 facing away from the valve stem
2, which has a base thickness d.sub.B between 2 mm and 5 mm.
Furthermore, the wall thickness d.sub.K of a valve neck 6 formed
between the valve stem 2 and the valve head 3 can be between 1.5 mm
and 5 mm.
[0025] The hollow valve 1 shown in the FIGURE can be employed as
part of a valve drive in an internal combustion engine (not shown
in the FIGURE) of a utility vehicle in order to open and close air
inlets and/or exhaust outlets. Said air inlet or exhaust outlet can
be surrounded by a valve seat, against which the hollow valve 1
lies with a contact section 7 in a closing position, in which it
closes the air inlet and the exhaust outlet respectively. Said
contact section 7, which is merely schematically indicated in the
FIGURE, is exposed to particular mechanical and thermal loads
during the operation of the valve drive in the internal combustion
engine. For this reason, the hollow valve 1 can be designed
hard-faced at least in the region of the contact section 7. Such
hard facing of the contact section 7 can be produced in particular
by means of plasma powder deposit welding, particularly preferably
using Iron (Fe) or Cobalt (Co) as filler material.
* * * * *