U.S. patent application number 12/096396 was filed with the patent office on 2008-11-27 for protective shield for thermal and acoustic shielding of components of an internal combustion engine.
Invention is credited to Ralf Krus.
Application Number | 20080289902 12/096396 |
Document ID | / |
Family ID | 36992601 |
Filed Date | 2008-11-27 |
United States Patent
Application |
20080289902 |
Kind Code |
A1 |
Krus; Ralf |
November 27, 2008 |
Protective Shield for Thermal and Acoustic Shielding of Components
of an Internal Combustion Engine
Abstract
The invention relates to a protective shield for the thermal and
acoustic shielding of a components of an internal combustion
engine, comprising a metal net with a multiplicity of through
apertures; at least on absorber layer of a sound-absorbing
material; and a carrier plate; wherein the metal net is arranged on
the side of the protective shield facing the component; the at
least one absorber layer is arranged between the metal net and the
carrier plate; and the carrier plate in its edge region is folded
over about the edge of the metal net.
Inventors: |
Krus; Ralf; (Lindlar,
DE) |
Correspondence
Address: |
DICKINSON WRIGHT PLLC
38525 WOODWARD AVENUE, SUITE 2000
BLOOMFIELD HILLS
MI
48304-2970
US
|
Family ID: |
36992601 |
Appl. No.: |
12/096396 |
Filed: |
August 11, 2006 |
PCT Filed: |
August 11, 2006 |
PCT NO: |
PCT/EP2006/007991 |
371 Date: |
June 6, 2008 |
Current U.S.
Class: |
181/290 |
Current CPC
Class: |
B60R 13/0838 20130101;
B60R 13/0876 20130101; B60R 13/0884 20130101 |
Class at
Publication: |
181/290 |
International
Class: |
E04B 1/88 20060101
E04B001/88 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 6, 2005 |
DE |
10 2005 058 253.2 |
Claims
1. Protective shield for the thermal and acoustic shielding of a
component of an internal combustion engine, comprising: a metal net
having a multiplicity of through apertures and an edge; at least
one absorber layer of a sound-absorbing material; and a carrier
plate; wherein the metal net is arranged on the side of the
protective shield facing the component; the at least one absorber
layer is arranged between the metal net and the carrier plate; and
an edge region of the carrier plate is folded over about the edge
of the metal net.
2. The protective shield according to claim 1, wherein the metal
net includes a depression, and the at least one absorber layer is
arranged within this depression.
3. The protective shield according to claim 2, wherein the metal
net is spaced from the carrier plate within the depression by at
least about 5 mm.
4. The protective shield according to claim 1, wherein the total
area of the through apertures in the metal net equals about 20 to
30% of the total area of the metal net.
5. The protective shield according to claim 1, wherein the carrier
plate comprises an aluminized steel plate with a thickness of about
approximately 0.4 mm.
6. The protective shield according to claim 1, wherein the metal
net comprises a wire mesh of aluminized metal wire.
7. The protective shield according to claim 1, wherein the metal
net comprises a wire mesh of galvanized metal wire.
8. The protective shield according to claim 1, wherein the metal
net comprises a wire mesh of stainless steel wire.
9. The protective shield according to claim 1, wherein the
sound-absorbing material comprises a fiber material.
10. The protective shield according to claim 9, wherein the fiber
material is basalt wool having, a specific weight of about 960
g/m.sup.3.
11. The protective shield according to claim 1, wherein the
sound-absorbing material comprises a foam rubber material.
12. The protective shield according to claim 11, wherein the foam
rubber material is melamine foam.
13. The protective shield according to claim 1, wherein the at
least one absorber layer is a multi-layer composite layer.
14. The protective shield according to claim 1, wherein the carrier
plate on the side facing the at least one absorber layer comprises
a sound-absorbing surface structure.
15. The protective shield according to claim 1 including fastening
means.
Description
[0001] The present invention relates to a multi-layer protective
shield which serves for the thermal and acoustic shielding of
components of an internal combustion engine and of turbochargers,
catalytic converters, exhaust manifolds and the like.
[0002] Shields of this type are used on motor vehicles but also
comparable machines for heat and sound shielding of components.
Such components are mainly constituent parts of the exhaust system,
i.e. catalytic converters, exhaust manifolds, turbochargers and the
like. The shields are to shield the interior space of the vehicle
against the high temperatures and the sound that develops through
vibrations that occur. In order to meet the ever more stringent
regulations in terms of the external sound level of vehicles the
shields are to preferably absorb, i.e. not simply reflect
noises.
[0003] Since the mentioned components can get very hot in
operation, thermal shielding is indispensable in order to prevent
that other vehicle components are detrimentally affected by the
high temperatures. However, an application can also consist in
conversely thermally shielding the section of the exhaust system
from the engine as far as to the catalytic converter. Since such
exhaust catalytic converters require a certain minimum temperature
for their correct and best possible functioning, faster reaching of
the operating temperature can be achieved through such "converse"
shielding. As a result, the exhaust values of the respective
vehicle can be improved.
[0004] Corresponding shields can also be used in the engine
compartment in order to protect components such as for example
plastic hoses, electrical wiring, engine electronics etc. against
excessive temperatures. There is a plurality of possibilities for
achieving thermal shielding. One of these consists in the use of
heat-insulating materials in the shield, for example foam-like
materials or fibre materials which, because of their comparatively
large content of air, are poor heat conductors.
[0005] Another or additional possibility is to reflect the heat
radiation from hot components on the shield, which for instance can
be achieved through metal coatings. Such reflection is most easily
achieved through a solid plate. Such air and thus sound-impermeable
plates however are disadvantageous with regard to sound insulation,
since the sound is substantially reflected completely. In
unfavourable cases even resonance can be caused which brings about
droning and similar undesirable acoustic effects.
[0006] Acoustic shielding can be obtained through special
sound-absorbing surface structures, but this is generally difficult
to establish and/or requires certain minimum thicknesses of the
corresponding layers, which is a disadvantage in the partly
confined conditions in modern vehicles.
[0007] Another possibility therefore consists in using a material
with permeable pores. Within such pores the mechanical energy of
sound waves can be converted into heat through friction, so that
acoustic shielding is obtained. Through the air content in the
pores, thermal insulation is additionally achieved.
[0008] A shield, which is to comprise both good acoustic as well as
thermal shielding characteristics, is therefore generally composed
of various materials in accordance with the problems discussed
above. In addition, such a shield must still have additional
mechanical characteristics.
[0009] These include stability with regard to the mechanical loads
that occur when operating a vehicle, i.e. the fatigue strength of
the fastening points. In addition, installing such a shield should
be preferably simple and safe, i.e. it is preferred that no sharp
edges are present whatsoever which can cause injuries to persons or
damage to other vehicle components.
[0010] A multi-layer shield, having layers of various materials,
should additionally be producible in the simplest manner possible
and with few steps.
[0011] It is therefore an object of the present invention to
provide a heat and sound protective shield which has both good
thermal as well as acoustic shielding characteristics and good
mechanical stability, which is easy to manufacture and handle.
[0012] According to an aspect of the present invention a protective
shield is provided for the thermal and acoustic shielding of a
component of an internal combustion engine. The protective shield
comprises a metal net with a multiplicity of through apertures; at
least one absorber layer of a sound-absorbing material; and a
carrier plate. Here, the metal net is arranged on the side of the
protective shield facing the component, the at least one absorber
layer is arranged between the metal net and the carrier plate and
the carrier plate in its edge region is folded over the edge of the
metal net.
[0013] Through this arrangement an effective acoustic/thermal
shield is provided, which is easy to manufacture, has good
mechanical stability and can be handled without the risk of
injuries to persons or damage to other vehicle parts.
[0014] In a preferred embodiment the metal net has a depression
wherein the at least one absorber layer is arranged within said
depression. As is shown in more detail in the following description
of preferred embodiments, this embodiment provides advantages in
both the manufacture as well as the operating characteristics of
the shield according to the invention.
[0015] In a preferred embodiment the distance between the metal net
and the carrier plate within the depression amounts to at least
approximately 5 mm.
[0016] In a preferred embodiment the overall area of the through
apertures in the metal net amount to between 20 to approximately
30% of the total area of the metal net.
[0017] In a preferred embodiment the carrier plate is an aluminized
steel plate with a thickness of approximately 0.4 mm. The coating
can be provided as corrosion protection but also improve the heat
reflection of the shield.
[0018] In a preferred embodiment the metal net comprises a wire
mesh of aluminized metal wire. A wire mesh can be produced easily
and cost-effectively and can be protected against corrosion through
the aluminising, while the coating can also be advantageous for
increasing the heat reflection. In another preferred embodiment the
metal net comprises a wire mesh of galvanized metal wire. In a
further preferred embodiment the metal net comprises a wire mesh of
stainless steel wire, wherein in this case no corrosion protection
whatsoever is necessary.
[0019] In a preferred embodiment the sound-absorbing material
comprises a fibre material, which can be basalt wool with a
specific weight of approximately 950 g/m.sup.3. In another
preferred embodiment the sound-absorbing material comprises a foam
rubber material which can be melamine foam.
[0020] In a preferred embodiment the at least one absorber layer is
a multi-layer composite layer.
[0021] In a preferred embodiment the carrier plate on the side
facing the at least one absorber layer comprises a sound-absorbing
surface structure. As a result, sound absorption can be
improved.
[0022] In a preferred embodiment fastening means are provided in
the edge region in order to attach the protective shield. The edge
region is particularly suited to provide such fastening means
therein, because of the good stability and durability in the
folded-over region.
[0023] The present invention is explained in more detail in the
following making reference to the enclosed drawings, wherein
[0024] FIG. 1 shows an embodiment of the present invention in cross
section; and
[0025] FIG. 2 shows an alternative embodiment of the present
invention in cross section.
[0026] FIG. 1 shows an embodiment of the protective shield
according to an invention in a cross-sectional view which is
arranged as shield of a component 8 of an internal combustion
engine. The component 8 can for example be a turbocharger, a
catalytic converter or another component which gets hot in
operation, i.e. constitutes a source of heat. The heat output is
frequently also connected with sound radiation such as is the case
for example with silencers or turbochargers.
[0027] The term "porosity" is used in the following in connection
with the present invention. Porosity according to the invention
means the part of the metal net or mesh which is permeable, i.e.
the component of the area of such a layer that is assumed by
through apertures based on the total area of the respective
layer.
[0028] Facing the heat source 8 is located a permeable metal net 2
such as wire mesh or netting. The metal net 2 thus has through
apertures which are thus "porous" or air-permeable. On the side of
the metal net 2 facing away from the component 8 is located at
least one absorber layer 4 which has a sound-absorbing function.
This layer 4 can be a composite layer. The shielding element
according to the invention is enclosed by a carrier plate 6.
[0029] The carrier plate 6 is folded over about the layer 2 in its
edge region 10 (indicated by the dashed circle). In the embodiment
shown here the edge region 10 is only folded over about the metal
net layer 2. The metal net 2 forms a depression or pocket in which
the absorber layer 4 is located. Forming such a pocket facilitates
the manufacturing process of the shielding element according to the
invention, since the absorber layer in this case can be inserted
easily and thus is already fixed in a preliminary manner. In other
words it is easier to arrange the layers on top of one another as
an accurate fit when producing the shield than without such a
pocket.
[0030] However, the invention is not restricted to this embodiment;
in other embodiments (not shown) no such pocket is present, in this
case the absorber layer 4 and the metal net layer 2 lie on top of
each other over their entire area. In this case the carrier plate 6
is then folded over also about the edges of both layers 2,4. Since
in this case the absorber layer at its edges is additionally
clamped in between carrier plate 6 and metal net layer 4, slipping
of the absorber layer 4 can be effectively prevented with such an
embodiment.
[0031] The protective shield according to the invention possesses a
double shielding effect against heat and sound radiation. Here it
must be noted that for heat radiation a type of shielding other
than for sound is desired. While with heat radiation it is
desirable to reflect such heat radiation to the greatest possible
extent, i.e. to discharge it to the environment, exactly the
opposite effect is desirable in the case of sound. Sound waves are
not to be reflected, which increases the external noises of the
vehicle and in unfavourable cases can also result in resonances
("droning"), but instead are to be completely absorbed if
possible.
[0032] On the one hand (mechanical) sound waves are converted in
the metal net 2 into heat through friction, while on the other hand
(electromagnetic) heat radiation is reflected to a certain degree
through the non-permeable component of the area of the metal net 2.
This effect can be further increased through suitable coating. The
absorber layer 4 is provided in order to absorb remaining sound and
residual heat (which is also transmitted through convection). The
carrier plate 6 then forms the enclosing barrier for sound and
heat.
[0033] Through the distance between carrier plate 6 and metal net 2
(depending on embodiment within the pocket formed or in other
embodiments over the entire area) the effectiveness of the shield
can be adapted to certain frequency ranges. Greater distances shift
the frequency absorption curve towards lower frequencies and vice
versa. This is advantageous since depending on the component to be
shielded a specific frequency range can be covered. For example in
the case of turbochargers rather high frequencies ("whistling")
occur because of their high speed while other sections of the
exhaust system generate comparatively lower frequencies.
[0034] In the embodiment shown in FIG. 1 this distance can be
advantageously determined through the depth of the pocket. Since
metal net and carrier plate as a rule will be clearly more
compression-resistant than for example the absorber layer
consisting of foams, a defined distance for the intended frequency
range can be easily maintained in this way whereas without such a
pocket the absorber layer would be deformable to a greater extent.
Through the deformation, i.e. flattening of the absorber layer the
defined distance would be changed or reduced so that frequencies
other than the desired ones would be absorbed, while the
frequencies actually to be shielded would then be allowed to pass
through to an undesirably greater degree.
[0035] Thus, through the embodiment shown in FIG. 1 a
shape-retaining protective shield is obtained that will not
substantially change the distance between carrier plate and metal
net even in operation. The folding over or flanging over of the
carrier plate makes possible simple and cost-effective manufacture
of the multi-layer protective shield. In addition, the handling
especially during assembly is facilitated since the folded-over
region encloses sharp edges of the metal net. In the edge region
fastening means can also be provided in a simple manner (not
shown), which make possible secure fastening of the protective
shield and which show no tendency to tear out during continuous
operation. Such fastening means can for example be bores for
screws, rivets or the like which are provided in the edge
region.
[0036] FIG. 2 shows an alternative embodiment of the protective
shield of FIG. 1. Here, a sound-absorbing surface configuration or
structure 12 is additionally present on the inner side of the
carrier plate 6. This structure 12 for example can be provided
through punching-in or the like in the carrier plate 6. As a
result, the sound absorption of the shield according to the
invention is further improved. An additional advantage with a
structure as shown here consists in that slipping of the absorber
layer 4 is additionally reduced. By providing a surface structure
the adaptation of the absorption curve can also be improved.
[0037] In all embodiments of the invention adaptation of the sound
absorption can also be easily obtained in that the metal net is
rolled to a desired porosity, i.e. the pore sizes are brought to
desired values through rolling or the like.
[0038] A multi-layer heat protection shield for use in the vehicle
engine region is described in the present invention, for the
thermal and acoustic shielding of hot components such as
turbocharger, exhaust manifold etc. The sound-absorbing effective
heat shield comprises at least 3 layers.
[0039] Here, the layer facing the sound/heat source is a metal net,
e.g. a metal wire mesh or netting. This is followed by one or a
plurality of layers of an absorber material for sound absorption.
Finally, the absorber layer(s) is followed by a metal plate (for
example an aluminized steel plate of 0.4 mm thickness), which holds
together the layer composition through folding over of the edge
region at least about the metal net.
[0040] As a result it is prevented that an exposed edge of the
netting results in sharp edges and thus constitutes potential risk
of injury or the risk of damaging other vehicle parts. The
folded-over edge region ensures easier and more secure handling
during the assembly of the shield according to the invention. The
folding-over also gives the shield greater stiffness and increased
durability during continuous engine operation.
[0041] The metal wire mesh layer can be embodied as regular or
irregular netting, i.e. the size and arrangement of the through
apertures or "pores" is either regular or irregular. "Porosity" in
terms of the present invention must be understood as the total area
of the through apertures based on the total area of the mesh layer.
Through its porosity (20 to 30%) the netting is able to convert
impinging sound waves into heat through friction, thus damping said
sound waves.
[0042] Here, the regular or irregular distances or the size of the
pores of the netting can be configured depending on the frequency
range of the sound waves to be shielded. An additional possibility
of influencing the porosity (adaptation to different frequencies)
of the netting can be effected through flat-rolling or compressing
to various thicknesses of the netting, as a result of which the
porosity can be changed. As a result of this, additional stiffness
of the netting can be achieved in addition.
[0043] In order to guarantee the corrosion resistance of the
netting it is advantageous to additionally coat the netting with
zinc or aluminium. Nettings of stainless steel require no such
coating. In addition to the above-mentioned tasks the netting layer
should additionally ensure the accommodation of the absorber
material during the manufacturing process of the shield.
[0044] To this end, a type of depression or pocket for example in
the depth of the thickness of the absorber material, is pressed
into the netting into which the absorber material can be placed.
The depth of the pocket produces a defined distance of the mesh
layer to the terminal or carrier plate, which in a preferred
embodiment should at least amount to 5 mm. The greater the distance
between the netting and the terminal plate is selected, the more
the frequency absorption curve is displaced to lower frequency
ranges. Thus the absorption can be suitably adapted to the
requirements through suitable selection of this distance.
[0045] The absorber material in the multi-layer construction of the
shield assumes the task of the residual absorption of the sound
waves that pass through the netting. To this end, fibre materials
(for instance basalt wool 960 g/m.sup.3) or foams (for example
melamine foam) can be used. In order to be able to shift the degree
of absorption into desired frequency ranges, the absorber material
can be single or multi-layered. It can also have different
densities in the layer composition in order to be able to cover as
wide as possible a frequency range.
[0046] Through additional coating of the netting the reflection of
the heat can be additionally increased and the thermal shielding
effect improved as a result.
[0047] By using temperature-resistant materials for the outer
layers in conjunction with basalt or silica fibres for the absorber
layers of the shield according to the invention, direct screwing to
hot engine components such as turbochargers, manifolds, catalytic
converters, silencers etc. is possible. In contrast, shields acting
acoustically and thermally in a conventional manner can only be
installed on cold vehicle components such as body, hoods, plastic
parts etc.
* * * * *