U.S. patent application number 12/067105 was filed with the patent office on 2009-12-10 for exhaust gas cleaning component for cleaning an internal combustion engine exhaust gas.
This patent application is currently assigned to Daimler AG. Invention is credited to Clemens Brinkmeier, Christof Schoen, Guido Vent.
Application Number | 20090301069 12/067105 |
Document ID | / |
Family ID | 37497058 |
Filed Date | 2009-12-10 |
United States Patent
Application |
20090301069 |
Kind Code |
A1 |
Brinkmeier; Clemens ; et
al. |
December 10, 2009 |
Exhaust Gas Cleaning Component for Cleaning an Internal Combustion
Engine Exhaust Gas
Abstract
A component for cleaning the exhaust gas in an internal
combustion engine has a carrier body with a plurality of flow ducts
for the exhaust gas. At least some of the walls (3) of the flow
ducts have a coating with an oxygen storage capacity. According to
the invention, the coating with an oxygen storage capacity is
provided for a first delimited region of the carrier body, while a
second delimited region of the carrier body is made free of a
coating with an oxygen storage capacity or has a coating with a
greatly reduced oxygen storage capacity compared to the first
region.
Inventors: |
Brinkmeier; Clemens;
(Stuttgart, DE) ; Schoen; Christof; (Remshalden,
DE) ; Vent; Guido; (Backnang, DE) |
Correspondence
Address: |
CROWELL & MORING LLP;INTELLECTUAL PROPERTY GROUP
P.O. BOX 14300
WASHINGTON
DC
20044-4300
US
|
Assignee: |
Daimler AG
Stuttgart
DE
|
Family ID: |
37497058 |
Appl. No.: |
12/067105 |
Filed: |
August 26, 2006 |
PCT Filed: |
August 26, 2006 |
PCT NO: |
PCT/EP2006/008383 |
371 Date: |
January 2, 2009 |
Current U.S.
Class: |
60/297 |
Current CPC
Class: |
F01N 2510/0682 20130101;
F01N 3/2803 20130101; B01D 53/9495 20130101; Y02T 10/12 20130101;
B01D 53/9477 20130101; Y02T 10/22 20130101; F01N 2570/16 20130101;
F01N 2560/06 20130101; B01D 2255/206 20130101; B01D 2255/908
20130101; F01N 2510/06 20130101; B01D 53/945 20130101; B01J 35/0006
20130101 |
Class at
Publication: |
60/297 |
International
Class: |
F01N 3/035 20060101
F01N003/035 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 17, 2005 |
DE |
10 2005 044 545.4 |
Claims
1.-9. (canceled)
10. A component for cleaning the exhaust gas in an internal
combustion engine, said component comprising: a carrier body; and a
plurality of flow ducts which pass through the carrier body for
accommodating an exhaust gas flow; wherein, at least some of the
walls of the flow ducts have a coating with an oxygen storage
capacity; the coating with an oxygen storage capacity is provided
in a first delimited region of the carrier body; and a second
delimited region of the carrier body has no coating with an oxygen
storage capacity or has a coating with a greatly reduced oxygen
storage capacity, relative to oxygen storage capacity in the first
region.
11. The exhaust gas cleaning component as claimed in claim 10,
wherein at least one of the first region and second region extends
over an entire cross section of the carrier body, and is limited in
the axial direction with respect to the extent of the carrier
body.
12. The exhaust gas cleaning component as claimed in claim 10,
wherein the first region adjoins the second region.
13. The exhaust gas cleaning component as claimed in claim 10,
wherein the first region extends over more than half the length of
the carrier body.
14. The exhaust gas cleaning component as claimed in claim 10,
wherein the first region extends from a point which is spaced apart
from an inlet end of the carrier body in an axial direction, to an
outlet end of the carrier body.
15. The exhaust gas cleaning component as claimed in claim 10,
wherein at least two first regions which are spaced apart from one
another are provided.
16. The exhaust gas cleaning component as claimed in claim 10,
wherein the exhaust gas cleaning component comprises an exhaust gas
catalytic converter.
17. The exhaust gas cleaning component as claimed in claim 10,
wherein the exhaust gas cleaning component comprises exhaust gas
particle filter.
18. The exhaust gas cleaning component as claimed in claim 10,
further comprising a temperature recording device for recording a
temperature of the coating with an oxygen storage capacity in the
first region.
Description
[0001] This application is a National Stage of PCT International
Application No. PCT/EP2006/008383, filed Aug. 26, 2006, which
claims priority under 35 U.S.C. .sctn.119 to German Patent
Application No. 102005044545.4, filed Aug. 17, 2005, the entire
disclosure of which is herein expressly incorporated by
reference.
[0002] The invention relates to a component for cleaning the
exhaust gas in an internal combustion engine.
[0003] In order to clean the exhaust gases of an internal
combustion engines it is generally customary to provide, in the
exhaust section, a cylindrical carrier body with a plurality of
flow ducts through which the exhaust gases flow. For catalytically
assisted cleaning of exhaust gas, a catalytically active coating is
usually applied to the ducts, so that the exhaust gas which flows
through them comes into contact with the coating and exhaust gas
components catalyzed by the coating. The coatings frequently have
an oxygen storage capacity, which permits, in particular,
catalyzation of redox reactions.
[0004] Stressing due to elevated temperatures, however, can cause
the exhaust gas cleaning component to age, reducing its functional
capability. In an exhaust gas cleaning component having a coating
with an oxygen storage capacity, the aging can be accompanied by a
reduction in the oxygen storage function, reducing the reliability
of the exhaust gas cleaning component.
[0005] One object of the invention is therefore to provide an
improved exhaust gas cleaning component with improved operational
reliability.
[0006] This and other objects and advantages are achieved by the
exhaust gas cleaning component according to the invention, in which
the coating with an oxygen storage capacity is provided for a first
delimited region of the carrier body, and a second delimited region
of the carrier body is made free of a coating with an oxygen
storage capacity or has a coating with a greatly reduced oxygen
storage capacity compared to the first region.
[0007] Preferably the coating is the type referred to as a
washcoat. Depending on the intended function, it can contain finely
distributed, catalytically active noble metals (particularly of the
platinum group). If the coating has an oxygen storage capacity, it
contains a material which is capable of storing oxygen, such as for
example an oxide of an element of the rare earths. The material is
distributed homogeneously in the coating or the washcoat, so that
the coating has an overall oxygen storage capacity. Cerium
oxide-based oxides and/or praseodymium oxide-based oxides or mixed
oxides are particularly preferred as materials with an oxygen
storage capacity which are distributed homogeneously in the coating
so that the coating has an overall oxygen storage capacity.
[0008] For the first region, a proportion of approximately 20% to
70% of the material with an oxygen storage capacity is preferred in
the coating. In contrast, for the second region a content of less
than 10% is preferred. The second region can, however, also have a
coating which does not contain any such material at all or it can
be made completely free of a coating. For the sake of
simplification, the embodiments of the first and second regions are
referred to below as being an OSC-rich region and an OSC-poor or
OSC-free region (OSC=oxygen storage capacity).
[0009] In an embodiment according to the invention in which only a
delimited region of the carrier body is provided with an OSC-rich
coating, the chemical conversions that occur by means of the
material with an oxygen storage capacity are mainly or completely
limited to this region of the exhaust gas cleaning component. As a
result, the release of heat which is associated with the
conversions is also limited to region, so that the temperature
loading of the exhaust gas cleaning component is reduced, at least
in the other regions. Since the oxygen storage capacity can
decrease due to aging, recording or estimating the degree of aging
of the exhaust gas cleaning component is also made possible by
recording the oxygen storage capacity in the OSC-rich region. If
excessive aging (or aging which is occurring too quickly) is
detected, it is possible to intervene in the operation of the
internal combustion engine to counteract. As a result, the service
life and the operational reliability of the exhaust gas cleaning
component are also increased.
[0010] Depending on the application, different, shaped regions of
the exhaust gas cleaning component can be embodied as first and
second regions. For example, the first and/or the second region can
extend over the entire length of the carrier body, but not over the
entire cross-sectional area. The first and/or second regions can,
however, also extend over the entire cross-sectional area of the
carrier body, but not over its entire length.
[0011] In one embodiment of the invention, the first region and/or
the second region extend over the entire cross section of the
carrier body and are limited in the axial direction with respect to
the extent of the carrier body. This embodiment is particularly
easy to produce by means of immersion/suction coating.
[0012] In a further refinement of the invention, the first region
adjoins the second region. In particular there is provision for an
OSC-rich region to extend over the entire cross section of the
carrier body and to directly adjoin, in the axial direction, an
OSC-poor or OSC-free region which also extends over the entire
cross section. In this way, the junctions are defined unambiguously
and are localized in the axial direction on the carrier body.
[0013] In a further refinement of the invention, the first
(OSC-rich) region extends over the greater part of the length of
the carrier body. This embodiment is advantageous in particular for
exhaust gas cleaning components which require a large oxygen
storage capacity in terms of absolute value for their function.
This is the case, for example, in three-way catalytic
converters.
[0014] In a further refinement of the invention, the first
(OSC-rich) section extends from a point which is spaced apart from
the inlet end of the carrier body in the axial direction to the
outlet end of the carrier body. An inlet-end (preferably
disk-shaped) section of the carrier body is therefore made OSC-poor
or OSC-free. This prevents materials which store oxygen from
experiencing increased aging in the inlet region of the exhaust gas
cleaning component (which is usually particularly subject to
temperature stresses). In addition, heat-supplying reactions which
occur by means of the material which stores oxygen are moved
axially rearward from the inlet region. On the other hand,
downstream of the OSC-poor or OSC-free inlet region there is still
sufficient oxygen storage capacity available for the function of
the exhaust gas cleaning component.
[0015] In a further refinement of the invention, at least two first
(OSC-rich) regions which are spaced apart from one another are
provided for the exhaust gas cleaning component. It may, in
particular, be advantageous for the functioning of an exhaust gas
catalytic converter as an exhaust gas cleaning component if
preferably respectively disk-shaped OSC-poor or OSC-free regions
and OSC-rich regions follow one another in the axial direction, in
a repeatedly alternating fashion.
[0016] In a further refinement of the invention, the exhaust gas
cleaning component comprises an exhaust gas catalytic converter.
The catalytic converter here may be either an unsupported or a
supported catalytic converter. One embodiment of the exhaust gas
cleaning component according to the invention is particularly
advantageously as a three-way catalytic converter.
[0017] In a further refinement of the invention, the exhaust gas
cleaning component is comprises an exhaust gas particle filter,
preferably with a so-called wall flow design. The ducts of the
particle filter can be catalytically coated here along their gas
inlet side and/or their gas outlet side, or may be essentially free
of a catalytic coating.
[0018] In a further refinement of the invention, temperature
recording devices are provided for recording the temperature of the
coating with an oxygen storage capacity in the first region. In
this way it is possible to record changes in temperature which are
caused by redox reactions which occur by means of the OSC-rich
coating. If, due to aging, the activity of the coating decreases,
that can be detected by reference to the recorded temperatures of
the coating. In particular, by recording the temperature of the
coating it is possible to detect a change in the modification
process of the material which stores oxygen. (Such change occurs
when oxygen is stored, since the change is usually accompanied by a
heat tone.) The oxygen storage capacity of the coating with an
oxygen storage capacity can therefore be recorded by means of the
recorded temperature of said coating. This makes it possible to
diagnose the exhaust gas cleaning component since aging-induced
degradation of the function of the coating which stores oxygen can
be detected by recording the temperature.
[0019] 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
[0020] FIG. 1 shows a first embodiment of the exhaust gas cleaning
component according to the invention;
[0021] FIG. 2 shows a second embodiment of the exhaust gas cleaning
component according to the invention;
[0022] FIG. 3 shows a third embodiment of the exhaust gas cleaning
component according to the invention;
[0023] FIG. 4 shows a fourth embodiment of the exhaust gas cleaning
component according to the invention;
[0024] FIG. 5 shows a fifth embodiment of the exhaust gas cleaning
component according to the invention;
[0025] FIG. 6 shows a side view of a first arrangement of a
temperature sensor for the exhaust gas cleaning component according
to the invention;
[0026] FIG. 7 shows a side view of a second arrangement of a
temperature sensor for the exhaust gas cleaning component according
to the invention;
[0027] FIGS. 8a to 8d show further advantageous embodiments of the
exhaust gas cleaning component according to the invention in
conjunction with a temperature sensor which is arranged according
to FIG. 6; and
[0028] FIGS. 9a to 9c show further advantageous embodiments of the
exhaust gas cleaning component according to the invention in
conjunction with a temperature sensor which is arranged according
to FIG. 7.
DETAILED DESCRIPTION OF THE DRAWINGS
[0029] FIG. 1 is a schematic illustration of an exhaust gas
cleaning component 1 which comprises an exhaust gas catalytic
converter with a honeycomb body design. Although the exhaust gas
catalytic converter 1 can be embodied as an unsupported catalytic
converter, in which the honeycomb body itself is composed of
catalytically active material, it is assumed below that there is a
supported exhaust gas catalytic converter with a metallic or
ceramic carrier body. A plurality of flow ducts 2, on at least part
of whose walls 3 a (preferably a catalytically active) coating is
applied (not illustrated in more detail), pass through the carrier
body. In its rear region 5 (relative to the direction of flow of
the exhaust gas which is indicated by the arrow 4) the exhaust gas
catalytic converter 1 has an OSC-rich coating (a coating with a
comparatively large oxygen storage capacity). On the other hand, in
the comparatively significantly shorter inlet-end region 6, the
exhaust gas catalytic converter 1 is made OSC-free or OSC-poor.
That is, it can be made free of coating, or can have a coating with
comparatively little or no oxygen storage capacity. For reasons of
production technology it is preferred if coatings are applied
approximately uniformly on the walls 3 of the flow ducts 2 in the
respective regions 5, 6 and comprise the entire cross section of
the exhaust gas catalytic converter 1.
[0030] The embodiment in FIG. 1, which is used near to the engine
as a first catalytic exhaust gas cleaning component in the exhaust
section of an internal combustion engine, is preferred. Such
exhaust gas cleaning components are subjected, particularly in
their inlet region, to high thermal stresses since the exhaust gas
which enters can be at high temperatures. Reactions of reactive
exhaust gas components with oxygen stored in the catalytic
converter and/or changes in the modification process of the oxygen
storage material itself can further increase the temperature stress
on the catalytic converter. In order to protect the inlet-end
region (which is important for the exhaust gas cleaning
performance) against excessively high temperatures it may therefore
be advantageous if the inlet region of the catalytic converter is
made OSC-poor or OSC-free. An inlet-end region 6 of the exhaust gas
catalytic converter 1 which is made OSC-poor or OSC-free over
approximately 5 mm to 50 mm, or over approximately 5% to 50%, of
its overall length is advantageous. The directly adjoining,
downstream region 5 is preferably made uniformly OSC-rich.
[0031] FIG. 2 shows a second advantageous embodiment of an exhaust
gas cleaning component 1 which is embodied according to the
invention. In contrast to the embodiment in FIG. 1, an inlet-end
region 5 here is OSC-rich, and a directly adjoining, downstream
region 6 is made OSC-poor or OSC-free. This embodiment is
recommended if an increased oxygen storage capacity is not
necessary for functioning of the exhaust gas cleaning component 1.
This may be done, for example, in an exhaust gas cleaning component
1 which is embodied as an oxidation catalytic converter or as a
soot filter. The inlet-end OSC-rich region 5 can serve, in
particular in this case, as a diagnostic region in such a way that
the aging of the exhaust gas cleaning component 1 is determined by
repeated determinations of the oxygen storage capacity of the
OSC-rich region 5. An inlet-end region 5 of the exhaust gas
cleaning component 1 which is made OSC-rich over approximately 5 mm
to 50 mm, or over approximately 5% to 50%, of its overall length is
advantageous.
[0032] FIG. 3 shows a third advantageous embodiment of an exhaust
gas catalytic converter 1 which is embodied according to the
invention. In contrast to the embodiment in FIG. 1, an inlet-end
region 5' is made OSC-rich, as is a rear region 5; that is, such
regions are embodied with a coating having comparatively high
oxygen storage capacity. A central region 6 which is made OSC-poor
or OSC-free is arranged between the OSC-rich regions 5', 5. The
central region 6 which is made OSC-poor or OSC-free preferably
makes up approximately 20% to 30% of the total length of the
exhaust gas catalytic converter 1. The exhaust gas catalytic
converter 1 therefore has an OSC-rich coating over the greater part
of its length so that its most important function is available to a
significant degree.
[0033] FIG. 4 illustrates a further advantageous embodiment of an
exhaust gas catalytic converter 1. In this embodiment, only a
central region 5 is made OSC-rich. On the other hand, a directly
adjoining, front region 6 and a directly adjoining rear region 6'
are made OSC-poor or OSC-free. Such an embodiment is advantageous,
in particular, for catalytic exhaust gas cleaning components in
which a comparatively small oxygen storage capacity is necessary.
Compared to a coating which is embodied with a uniformly reduced
oxygen storage capacity over the entire length, this embodiment is
advantageous in that only one region has a reduced temperature
resistance. The central region 5 preferably makes up approximately
20% to 60% of the total length of the exhaust gas catalytic
converter 1.
[0034] In the further advantageous embodiment which is illustrated
in FIG. 5, OSC-rich regions 5, 5', 5'', 5''' alternate with
OSC-poor or OSC-free regions 6, 6', 6'', 6'''. Here, it is
possible, as illustrated, for the inlet-end region 6 to be made
OSC-poor or OSC-free. However, it may also be advantageous if the
inlet region has a coating with a high oxygen storage capacity.
Since in particular cerium-containing coatings can catalyze water
vapor shift reactions with the formation of hydrogen it is possible
in such a case to use hydrogen which is formed in the regions with
a high oxygen storage capacity in the subsequent regions with a low
oxygen storage capacity or with no oxygen storage capacity. In this
way it is possible to extend the catalytic function of the exhaust
gas catalytic converter 1. Each region preferably makes up
approximately 20% of the total length of the exhaust gas catalytic
converter 1. The individual regions may be made approximately of
equal length or with different lengths.
[0035] The inventive embodiment of an exhaust gas cleaning
component with a first delimited region with OSC-rich coating and a
second delimited region which is made OSC-poor or OSC-free results
in an improved catalytic function of the exhaust gas cleaning
component. Furthermore, the embodiment according to the invention
can be used to monitor aging of the exhaust gas cleaning component.
For this purpose, the temperature of the coating with an oxygen
storage capacity is recorded in the OSC-rich region in such a way
that reaction heat of a change in the modification process of the
material with an oxygen storage capacity which occurs when oxygen
is stored can be recorded. When oxygen is stored in the material
with an oxygen storage capacity, the material changes from an
oxygen-poor modification into an oxygen-rich modification. For
example, in the case of cerium oxide-based materials with an oxygen
storage capacity, cerium oxide changes from its three-value form
(Ce2O3) into the four-value form (CeO2). The corresponding oxygen
absorbing reaction takes place very quickly in an exothermal
fashion, the temperature of the coating with an oxygen storage
capacity increases when oxygen is stored. The nature of the
temperature increase can therefore determine whether and to what
extent a change in the modification process has occurred, i.e.
whether and to what extent material with an oxygen storage capacity
is available. Since aging of a catalytic converter due, for
example, to the effect of increased temperatures or of poisoning,
becomes apparent through a reduction in the oxygen storage
capacity, it is possible, by evaluating the increase in temperature
when oxygen is stored, to assess the state of aging of the exhaust
gas cleaning component and carry out diagnostics. For this purpose,
for example the magnitude of the increase in temperature is
detected and compared with a reference value.
[0036] The nature and the effect of the increase in temperature
which occurs when oxygen is stored in the material with an oxygen
storage capacity must be clearly differentiated here from increases
in temperature which may occur due to the occurrence of catalyzed
gas reactions. While, in the case mentioned first, an exothermal
change in the modification process in the material with an oxygen
storage capacity is the cause of the increase in temperature, in
the case mentioned second that cause is exothermal reactions of
exhaust gas components. The reaction heat which is released with
the storage of oxygen therefore acts directly in the coating itself
and as a result heats it up very quickly, causing an increase in
temperature, even if no exothermal gas reactions occur.
[0037] In contrast, gas reactions which are catalyzed by the
coating heat up the coating indirectly and occur after a delay, in
particular in regions of the exhaust gas cleaning component which
are at a distance from the gas inlet. Consequently, when
temperature is recorded at a distance from the exhaust gas inlet,
it is possible to differentiate between the temperature-increasing
effect of a gas oxidation and a change in the modification process
in the coating. This means that when temperature is recorded at a
distance from the exhaust gas inlet, it is possible to monitor the
exhaust gas cleaning component particularly reliably by determining
the oxygen storage capacity which is present there. An increase in
temperature which occurs immediately when there is a change of
operating mode of the internal combustion engine with a changeover
from reducing exhaust gas conditions with a deficit of oxygen to
oxidizing exhaust gas conditions with an excess of oxygen is
preferably evaluated. In this way it is possible to effectively
eliminate temperature effects which are caused by gas
oxidations.
[0038] The reaction heat of the change in the modification process
which occurs when oxygen is stored in the material with an oxygen
storage capacity can advantageously be recorded with exhaust gas
cleaning components which are predominantly provided from the
outset, with an OSC-rich coating corresponding to the embodiments
illustrated in FIGS. 1 and 3. The temperature can be recorded at a
single point in the OSC-rich coating or at a plurality of points
which are offset with respect to one another axially and/or
radially.
[0039] In order to monitor an exhaust gas cleaning component for
which no coating is provided with an oxygen storage capacity from
the outset, it is possible to provide the latter locally with such
a coating in a comparatively small, delimited region. Evaluating
the increase in temperature which occurs in this region and which
is associated with the storage of oxygen therefore permits
monitoring and diagnostics to be carried out even on components
which are largely free of a coating with an oxygen storage
capacity. In this respect it is advantageous to embody the exhaust
gas cleaning component in accordance with the variants illustrated
in FIGS. 2, 4 and 5.
[0040] In order to record the reaction heat of the change in the
modification process which occurs when oxygen is stored in the
material with an oxygen storage capacity, a temperature sensor is
preferably placed in a heat-conducting connection with the
corresponding coating. The temperature sensor is preferably
introduced into the exhaust gas cleaning component in the radial or
axial direction and with its temperature-sensitive region in
heat-transmitting contact with the OSC-rich coating.
[0041] FIG. 6 is a schematic view of a radial feed of a temperature
sensor 7 into an exhaust gas cleaning component 1. The
temperature-sensitive region of the temperature sensor 7 can be
arranged off-center here; and it of course also possible to
position it approximately at the level of the longitudinal central
axis.
[0042] FIG. 7 is a schematic view of an axial feed of a temperature
sensor 7 into an exhaust gas cleaning component 1. It is not
necessary for the temperature sensor 7 to be positioned at the
level of the longitudinal central axis as illustrated. The sensor
axis can be displaced parallel to the longitudinal central axis,
intersect it or be at an angle to it.
[0043] In exhaust gas cleaning components which, for functional
reasons, are made largely free of a coating with an oxygen storage
capacity or are made with a coating with a low oxygen storage
capacity, it is possible to provide an OSC-rich coating which is
provided only in the direct vicinity of the temperature sensor or
its temperature-sensitive region. Exemplary embodiments of radial
forms of feed for the temperature sensor are illustrated in section
in FIGS. 8a to 8d corresponding to the sectional lines A and B
indicated in FIG. 6. In FIGS. 8a and 8c, a region 5, which extends
over the entire length of the exhaust gas cleaning component 1 but
only part of the cross section and into which the temperature
sensor 7 dips, is provided with an OSC-rich coating. In FIG. 8a,
the latter surrounds the temperature-sensitive part of the
temperature sensor 7, here its tip, and extends as far as the outer
surface of the exhaust gas cleaning component 1. In FIG. 8c, the
OSC-rich region 5 only surrounds the temperature-sensitive region
of the temperature sensor 7 in the radial direction. However,
according to FIGS. 8b and 8d the OSC-rich region 5 is preferably
made comparatively short in the axial direction and is only present
in the surroundings of the temperature sensor 7.
[0044] In FIG. 8b, the OSC-rich region 5 surrounds the entire
sensor 7 from its entry point into the exhaust gas cleaning
component 1, and in FIG. 8d the OSC-rich region 5 surrounds only
the temperature-sensitive tip of the temperature sensor 7. With the
embodiments illustrated in FIGS. 8a to 8d it is therefore possible
to monitor for aging of components even on exhaust gas cleaning
components which have a coating with little or no oxygen storage
capacity.
[0045] As illustrated in FIGS. 9a to 9c, it is, in an analogous
fashion, also possible to introduce a temperature sensor 7 (for
example, a thermoelement) axially into the exhaust gas cleaning
component 1 which is to be monitored. Temperature sensor 7 may be
in heat-transmitting contact with an OSC-rich coating which is
formed uniformly over the entire length of the component or in an
axial region or, as illustrated, said temperature sensor 7 may be
in heat-transmitting contact with an OSC-rich coating which is
present only in the direct vicinity of the temperature-sensitive
region of said temperature sensor 7.
[0046] 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.
* * * * *