Title of Invention	INTERNAL COMBUSTION ENGINE TURBOCHARGED USING EXHAUST GAS TURBOCHARGER
Abstract	The present invention relates to an internal combustion engine turbocharged using an exhaust gas turbocharger, particularly a diesel engine of a vehicle, in whose exhaust system an exhaust gas posttreatment unit having at least one SCR catalyst is provided, to which ammonia, which is producible in an ammonia reactor from a urea-water solution or solid urea, may be supplied as a reducing agent for the purpose of nitrogen oxide reduction. The present invention comprises the ammonia reactor (11) being situated externally on the turbine housing (5) of the exhaust gas turbocharger-using its thermal radiation for ammonia production.

Title of Invention

INTERNAL COMBUSTION ENGINE TURBOCHARGED USING EXHAUST GAS TURBOCHARGER

Abstract

The present invention relates to an internal combustion engine turbocharged using an exhaust gas turbocharger, particularly a diesel engine of a vehicle, in whose exhaust system an exhaust gas posttreatment unit having at least one SCR catalyst is provided, to which ammonia, which is producible in an ammonia reactor from a urea-water solution or solid urea, may be supplied as a reducing agent for the purpose of nitrogen oxide reduction. The present invention comprises the ammonia reactor (11) being situated externally on the turbine housing (5) of the exhaust gas turbocharger-using its thermal radiation for ammonia production.

Full Text	Internal combustion engine turbocharged using exhaust gas turbocharger having an exhaust system having SCR catalyst(s) Description The present invention relates to an internal combustion engine turbocharged using an exhaust gas turbocharger having the features of the type specified in the preamble of Claim 1. Technological background: ammonia (NH3) is used as a reducing agent for the selective catalytic reduction (SCR) of NO, in the exhaust gas and diesel engines. This ammonia is to be produced through thermolysis of a urea-water solution or solid urea. For this purpose, there are various possibilities and types of ammonia reactors. In the simplest case, a ureawater solution is sprayed directly into the hot exhaust gas before the SCR catalyst(s). This has the disadvantage that the proportion of vaporized water is low and even at temperatures of 400°C: only a slight decomposition of the urea into ammonia (NH,) and jsocyanic acid (HNCO) occurs, which lowers the efficiency of the SCR catalyst(s). Catalytic therrnolysis of the urea-water solution using a hydrolysis catalyst in the secondary flow or of solid urea in an ammonia reactor in an exhaust gas auxiliary flow as a water vapor carrier allow a high-quality production of ammonia free of isocyanic acid. Urea is a salt-like solid which melts at approximately 133°C and vaporizes at temperatures between 350" - 400°C through rapid therrnolysis and forms ammonia (NH,) and isocyanic acid (HNCO) at the same time, according t 0 (NHi.)2C0 -+ NH3 + HNCO. Because of the presence of water vapor in the ammonia reactor, the isocyanic acid is also converted in a second step into ammonia and carbon dioxide, according to HNCO + H20 - NH:, + COz. Due to the elimination of the isocyanic acid, which tends to polymerize, this reaction prevents the formation of solid decomposition products such as cyanuric'acid, and finally allows a gas mixture containing ammonia to be provided, which does not contain any components that tend to accumulate in the exhaust gas line. Hydrolysis catalysts are either used in externally heated ammonia reactors situated outside an exhaust gas line or internally by exhaust gas lines as ammonia reactors, which are then heated by exhaust gas. Such hydrolysis catalysts make the exhaus: gas posttreatment systems significantly more expensive than such systems which manage without these catalysts. In addition, hydrolysis catalysts situated after the exhaust gas turbocharger in the exhausi, gas line have exhaust gas applied to them whose temperature level has already been lowered a relatively large amount, depending on the load state of the internal combustion engine, even below a temperature at which favorable hydrolysis of the urea is no longer possible. It is therefore the object of the present invention to show a way in which hydrolysis catalysts for ammonia production may be dispensed with, but the formation of harmful solid decomposition products is nonetheless avoidable This object is achieved according to the present invention in accordance with the characteristics of Claim 1 in that the ammonia reactor is situated externally on the turbine housing of the exhaus: gas turbocharger - whose thermal radiation is used for ammonia production. The present invention proceeds from the following considerations If one wishes to dispense with electrical heating of the vaporization/hydrolysis chamber in external ammonia reactors, another available heat source must be sought. Heat sources which provide the required temperature, in the range of 400°C or higher, may only be found very close to the engine on an internal combustion engine and must participate in the combustion process or be situated directly downstream therefrom. The present invention makes use of the exhaust gas iurbocharger as a heat source in this regard, whose hot turbine housing outer wall causes rather high thermal radiation depending on the load state. This high thermal radiation is normally dissipated unused or is lowered by a cooling airflow to avoid heat damage in the surroundings. The present invention makes use of this high thermal radiation of the turbine housing outer wall by using it as a heat source for the ammonia production. For this purpose, an ammonia reactor is assigned directly thereto, Its vaporizat~onlhydrolysis chamber is accordingly heated by the thermal radiation of the turbine housing outer wall. Further heating of the vaporizatio~ lhydrolysisc hamber is periormed by the exhaust gas applied thereto via a partial flow which - because it branches off before the exhaust gas turbine in its intake area or via a channel from the exhaust gas line or the exhaust gas manifold - still has a very high temperature level of approximately 700-750°C. This exhaust gas also flrnctions as a supplier.of the water vapor which is required for the conversion into NH: and COi of the isocyanic acid arising during the thermal decomposition of the urea, and thus contributes to preventing the occurrence of corrosively acting urea decomposition products such as cyanuric acid. The ammonia reactor is connected via a supply line to a dosing unit and this unit is connected in turn to a storage container either for a urea-water solution or solid urea, preferably spherical urea prills of premade size. Using the dosing unit, the relevant solid or liquid operating material is sprayed or injected in a regulated quantity via the supply line at a suitable point into the vaporization/hydrolysis chamber of the ammonia reactor. There are multiple possibilities for positioning or implementing the ammonia reactor on the turbine housing of the exhaust gas turbocharger. One possibility is to unify the ammonia reactor with the construction of the turbine housins of the exhaust gas turbocharger to form a unit in such a way that the vaporizationlhydrolysis chamber is delimited on the inside by the turbine housing outer wall and on the outside by a reactor outer wall cast thereon. Another possibility, which is less favorable, is to produce the ammonia reactor having a closed housing, comprising the vaporizatronlhydrolysis chamber, as a modular unit and then to attach it externally to the turbine housing of the exhaust gas turbocharger. At least the inner wall of the reactor housing is made of corrosion-proof metallic material which is resistant to high temperatures and is highly thermally conductive. This inner wall of the reactor housing is exactly tailored to the external shape of the turbine housing outer wall, so that in the installed position of the ammonia reactor, it presses intimately against the turbine housing outer wall and absprbs its thermal radiation. The situation according to the present invention of the ammonia reactor externally on the turbine housing of the exhaust gas turbocharger also has the additional effect that the ammonia reactor practically also forms a heat shield, through which the thermal shielding measures may be simplified and the cooling fan output may be reduced. Further details and embodiments of the achievement of the object according to the present invention are characterized in the subclaims. In the following, the present invention is explained ir, greater detail on the basis of multiple examples illustrated in the drawing. In the drawing: Figure 1 shows a section through a turbocharger having an ammonia reactor whose construction is unified with the turbine housing, Figure 2 shows a section through a turbocharger having another embodiment of an ammonia reactor whose construction is unified with the turbine housing, Figure 3 schematically shows a cross section through a turbine housing of a turbocharger having an ammonia reactor whose construction is unified therewith, Figure 4 shows an example of a nozzle or a channel end piece, and Figure 5 shows an associated nozzle or channel end piece support. In the drawing, an exhaust gas turbocharger is identified by 1, its exhaust gas turbine by 2, and its compressor by 3. Only the exhaust gas turbine 2 is of interest in connection with the present invention. Its turbine wheel is identified by 4 and its turbine housing by 5. Its outer wall is identified by 6: the turbine inlet by 7, and the turbine outlet by 8. The turbine inlet 7 of the exhaust gas turbine 2 is connected to an exhaust gas line section, such as the manifold or exhaust gas collecting line, via which it is supplied with the exhaust gas expelled by an internal combustion engine (also not shown), particularly a diesel engine of a vehicle as shown by arrow 9. At the outlet 8 of the exhaust gas turbine 2, an exhaust gas line ID is connected, in which an exhaust gas posttreatment unit, having at least one SCR catalyst and at least one muffler, is situated downstream from the exhaust gas turbocharger. The compressor 3 of the exhaust gas turbocharger sucks in filtered air, compresses it, and then supplies it via a charge air line to the internal combustion engine. An ammonia reactor 11 is situated externally according to the present invention on the turbine housing 5 - whose thermal radiation is used for ammonia production. It has a vaporizationlhydrolysis chamber 12, into which either a urea-water solution or solid urea, e.g., in the form of prernade, spherical urea prills, is fed in a dosed quantity at a suitable point 13. As shown in Figure 2: this operating materia! - urea prills or urea-water solution - is stored in a storage container 14 and fed using a dosing unit 15 in a quantity regulated in regard to the ammonia demand via a supply line 16 and 2 nozzle 17 into the vaporizationlhydrolysis chamber 12 In the examples shown, the ammonia reactor 11 according to the present invention forms a modular unit with the turbine housing 5 of the exhaust gas turbocharger 1, in which the vaporizationlhydrolysis chamber 12 is delimited on the 'inside by the turbine housing outer wall 6 and on the outside by a reactor outer wall 18 cast onto the latter. Ir; an alternative construct~on (not shown). the ammonia reactor 11 may be pre-manufactured as a separate unit and then attached to the tilrbine housing 5. In this case, the ammonia reactor 11 has a closed housing which comprises the vaporization/hydrolysis chamber. At least the inner wall of the reactor housing is made of corrosion-proof metallic material which is resistant to high temperatures and is highly thermal conductive. This inner wall of the reactor housing is exactly tailored to the external shape of the turbine housing outer wall 6, so that it presses intimately against the turbine housing outer wall 6 in the installed position of the ammonia reactor, preferably with contact. Independently of the type of implementation of the ammonia reactor 11, its vaporizaiionlhydrolysis chamber 12 is connected via a channel 19 (see Figure 3) to the exhaust gas path before or at the intake of the turbine 2 of the exhaust gas turbocharger I . Via this channel 19, the vaporization/hydrolysis chamber 12 may be supplied with an exhaust gas partial flow. \~hichis used both to in,zrease the temperature in the vaporization/hydrolysis chamber 12 and also as a source for ,water vapor, which is used for complete conversion of the isgcyanic acid initially arising during the ammonia production into ammonia and carbon diox- ~de. In the case of the examples shown in Figures 1 through 3, the channel 19 is implemented by a hole in the inlet area 7 of the turbine housing, which discharges into the vaporizaiionlhydrolysis chamber 12. In the above-mentioned alternative implementation of the ammonia reactor 11, the channel 19 would be implemented via a pipeline, The channel 19 may be implemented as a connection which is permanently permeable to a specific exhaust gas partial quantity, but alternatively may also be implemented as a connection which may be switched as needed for passage using 2 switching andlor throttle valve or may also be regulated in regard to the flow quantity. Ai the output, the vaporization/hydrolysis chamber 12 of the ammonia reactor 11 is connected via at least one channel 20 to an exhaust gas line 10, 102 connected to the turbine outlet 8. Via this channel or these channels 20, the ammonia produced in the ammonia reactor 11 or the gas mjxture containing this ammonia is transferable into the exhaust gas system 10, 10a. In the exemplary embodimen: shown in Figure 2, a section 10 a of the exhaust gas line 1C adjoins the outlet 8 of t h t~urb ine housins 5 in which - still close to the exhaust gas turbocharger 1 - an oxidation catalyst 21 used for NO - NO? conversion is installed. This exhaust gas line section 10a having the installed oxidation catalyst 21 is enclosed externally at a distance by a pipe 22, which also is connected to the outlet 8 of the turbine housing 5, its front face 23 there. The at least one channel, here multiple channels 20; dlscharge into this annular channei 24 thus resulting. In this case, the ammonia produced in the ammonia reactor i 1 or the gas mixture containing it is accordingly fed into the annular channel 24, which then conducts it as a parallel flow past the oxidation catalyst 21 and feeds its flow into the exhaust gas flow after the latter and then from there - mixed with the exhaust gas enriched with NO2 - jeeds it to the SCR catalyst(s). The channels 20 are implemented as holes which lead from the outer front face 23 of the turbine outlet 8 through the turbine housing wall section enclosing the turbine outlet 8 into the vaporization/hydrolysis chamber 12. The cross-section of the channel 20 or the entire cross-section of all channels 20 is dimensioned in accordance with the conversion speed of the starting material used for ammonia production - urea-water solution or solid urea - in such way that this conversion process into ammonia may occur completely and witho~r~ets idile. The wall delimiting the vaporization/hydrolysis chamber 12 may be provided internally with a catalytic coating favoring the conversion of the urea, e.g., titanium dioxide (Ti02). In addition, in the case of the examples shown in Figures 1 through 3, the outside of the iurbine housing outer wall 6 may have ribs or other projecting structures - for the purpose of increasing the heat-radiating area and thus the heat introduced into the vaporizationlhydrolysis chamber 12. To attach a nozzle used for feeding the urea-water solution or the end piece 25 of a pipe for injecting solid urea prills (see Figure 4), a support 26 (see Figure 5) may be provided, which is screwed into an attachment eye 27 provided externally on the ammonia reactor 11 and accommodates the nozzle or the end piece 25 of the pipe 16 forming the injection channel. As shown in Figure 5, the support 26 may have a plate 28 on its reactor-interior end. This plate 28, which is flushed on all sides by the hoi exhaust gas, may form the first conversion element for incident urea-water jets as a heating plate. In the case of solid urea, the plate 28 rnay be used as an impact plate, on which the injected urea prills may be smashed into multiple extremely small particles as they hit it, which favor the conversion process into ammonia. Using the ammonia reactor according to the p:resent invention situated around the turbine housing, ii is possible to dispense with costly and bulky hydrolysis reactors. The ammonia reactor itself only occupies a small amount of space, which is normally present in any case around the turbine of an exhaust gas turbocharger or remains free. In addition, the ammonia reactor according to the present invention may be implemented less expensively than a hydrolysis reactor in the final effect,

Full Text

Internal combustion engine turbocharged using exhaust gas turbocharger having an
exhaust system having SCR catalyst(s)
Description
The present invention relates to an internal combustion engine turbocharged using an exhaust
gas turbocharger having the features of the type specified in the preamble of Claim 1.
Technological background: ammonia (NH3) is used as a reducing agent for the selective
catalytic reduction (SCR) of NO, in the exhaust gas and diesel engines. This ammonia is to
be produced through thermolysis of a urea-water solution or solid urea. For this purpose,
there are various possibilities and types of ammonia reactors. In the simplest case, a ureawater
solution is sprayed directly into the hot exhaust gas before the SCR catalyst(s). This
has the disadvantage that the proportion of vaporized water is low and even at temperatures
of 400°C: only a slight decomposition of the urea into ammonia (NH,) and jsocyanic acid
(HNCO) occurs, which lowers the efficiency of the SCR catalyst(s). Catalytic therrnolysis of
the urea-water solution using a hydrolysis catalyst in the secondary flow or of solid urea in an
ammonia reactor in an exhaust gas auxiliary flow as a water vapor carrier allow a high-quality
production of ammonia free of isocyanic acid. Urea is a salt-like solid which melts at approximately
133°C and vaporizes at temperatures between 350" - 400°C through rapid therrnolysis
and forms ammonia (NH,) and isocyanic acid (HNCO) at the same time, according
t 0
(NHi.)2C0 -+ NH3 + HNCO.
Because of the presence of water vapor in the ammonia reactor, the isocyanic acid is also
converted in a second step into ammonia and carbon dioxide, according to
HNCO + H20 - NH:, + COz.
Due to the elimination of the isocyanic acid, which tends to polymerize, this reaction prevents
the formation of solid decomposition products such as cyanuric'acid, and finally allows
a gas mixture containing ammonia to be provided, which does not contain any components
that tend to accumulate in the exhaust gas line.
Hydrolysis catalysts are either used in externally heated ammonia reactors situated outside
an exhaust gas line or internally by exhaust gas lines as ammonia reactors, which are then
heated by exhaust gas. Such hydrolysis catalysts make the exhaus: gas posttreatment systems
significantly more expensive than such systems which manage without these catalysts.
In addition, hydrolysis catalysts situated after the exhaust gas turbocharger in the exhausi,
gas line have exhaust gas applied to them whose temperature level has already been lowered
a relatively large amount, depending on the load state of the internal combustion engine,
even below a temperature at which favorable hydrolysis of the urea is no longer possible.
It is therefore the object of the present invention to show a way in which hydrolysis catalysts
for ammonia production may be dispensed with, but the formation of harmful solid decomposition
products is nonetheless avoidable
This object is achieved according to the present invention in accordance with the characteristics
of Claim 1 in that the ammonia reactor is situated externally on the turbine housing of the
exhaus: gas turbocharger - whose thermal radiation is used for ammonia production.
The present invention proceeds from the following considerations
If one wishes to dispense with electrical heating of the vaporization/hydrolysis chamber in
external ammonia reactors, another available heat source must be sought. Heat sources
which provide the required temperature, in the range of 400°C or higher, may only be found
very close to the engine on an internal combustion engine and must participate in the combustion
process or be situated directly downstream therefrom. The present invention makes
use of the exhaust gas iurbocharger as a heat source in this regard, whose hot turbine housing
outer wall causes rather high thermal radiation depending on the load state. This high
thermal radiation is normally dissipated unused or is lowered by a cooling airflow to avoid
heat damage in the surroundings.
The present invention makes use of this high thermal radiation of the turbine housing outer
wall by using it as a heat source for the ammonia production. For this purpose, an ammonia
reactor is assigned directly thereto, Its vaporizat~onlhydrolysis chamber is accordingly heated
by the thermal radiation of the turbine housing outer wall. Further heating of the vaporizatio~
lhydrolysisc hamber is periormed by the exhaust gas applied thereto via a partial flow
which - because it branches off before the exhaust gas turbine in its intake area or via a
channel from the exhaust gas line or the exhaust gas manifold - still has a very high temperature
level of approximately 700-750°C. This exhaust gas also flrnctions as a supplier.of the
water vapor which is required for the conversion into NH: and COi of the isocyanic acid
arising during the thermal decomposition of the urea, and thus contributes to preventing the
occurrence of corrosively acting urea decomposition products such as cyanuric acid.
The ammonia reactor is connected via a supply line to a dosing unit and this unit is connected
in turn to a storage container either for a urea-water solution or solid urea, preferably
spherical urea prills of premade size. Using the dosing unit, the relevant solid or liquid operating
material is sprayed or injected in a regulated quantity via the supply line at a suitable
point into the vaporization/hydrolysis chamber of the ammonia reactor.
There are multiple possibilities for positioning or implementing the ammonia reactor on the
turbine housing of the exhaust gas turbocharger.
One possibility is to unify the ammonia reactor with the construction of the turbine housins of
the exhaust gas turbocharger to form a unit in such a way that the vaporizationlhydrolysis
chamber is delimited on the inside by the turbine housing outer wall and on the outside by a
reactor outer wall cast thereon.
Another possibility, which is less favorable, is to produce the ammonia reactor having a
closed housing, comprising the vaporizatronlhydrolysis chamber, as a modular unit and then
to attach it externally to the turbine housing of the exhaust gas turbocharger. At least the
inner wall of the reactor housing is made of corrosion-proof metallic material which is resistant
to high temperatures and is highly thermally conductive. This inner wall of the reactor
housing is exactly tailored to the external shape of the turbine housing outer wall, so that in
the installed position of the ammonia reactor, it presses intimately against the turbine housing
outer wall and absprbs its thermal radiation.
The situation according to the present invention of the ammonia reactor externally on the
turbine housing of the exhaust gas turbocharger also has the additional effect that the ammonia
reactor practically also forms a heat shield, through which the thermal shielding
measures may be simplified and the cooling fan output may be reduced.
Further details and embodiments of the achievement of the object according to the present
invention are characterized in the subclaims.
In the following, the present invention is explained ir, greater detail on the basis of multiple
examples illustrated in the drawing.
In the drawing:
Figure 1 shows a section through a turbocharger having an ammonia reactor whose construction
is unified with the turbine housing,
Figure 2 shows a section through a turbocharger having another embodiment of an ammonia
reactor whose construction is unified with the turbine housing,
Figure 3 schematically shows a cross section through a turbine housing of a turbocharger
having an ammonia reactor whose construction is unified therewith,
Figure 4 shows an example of a nozzle or a channel end piece, and
Figure 5 shows an associated nozzle or channel end piece support.
In the drawing, an exhaust gas turbocharger is identified by 1, its exhaust gas turbine by 2,
and its compressor by 3. Only the exhaust gas turbine 2 is of interest in connection with the
present invention. Its turbine wheel is identified by 4 and its turbine housing by 5. Its outer
wall is identified by 6: the turbine inlet by 7, and the turbine outlet by 8.
The turbine inlet 7 of the exhaust gas turbine 2 is connected to an exhaust gas line section,
such as the manifold or exhaust gas collecting line, via which it is supplied with the exhaust
gas expelled by an internal combustion engine (also not shown), particularly a diesel engine
of a vehicle as shown by arrow 9. At the outlet 8 of the exhaust gas turbine 2, an exhaust gas
line ID is connected, in which an exhaust gas posttreatment unit, having at least one SCR
catalyst and at least one muffler, is situated downstream from the exhaust gas turbocharger.
The compressor 3 of the exhaust gas turbocharger sucks in filtered air, compresses it, and
then supplies it via a charge air line to the internal combustion engine.
An ammonia reactor 11 is situated externally according to the present invention on the turbine
housing 5 - whose thermal radiation is used for ammonia production. It has a vaporizationlhydrolysis
chamber 12, into which either a urea-water solution or solid urea, e.g., in the
form of prernade, spherical urea prills, is fed in a dosed quantity at a suitable point 13.
As shown in Figure 2: this operating materia! - urea prills or urea-water solution - is stored in
a storage container 14 and fed using a dosing unit 15 in a quantity regulated in regard to the
ammonia demand via a supply line 16 and 2 nozzle 17 into the vaporizationlhydrolysis chamber
12
In the examples shown, the ammonia reactor 11 according to the present invention forms a
modular unit with the turbine housing 5 of the exhaust gas turbocharger 1, in which the vaporizationlhydrolysis
chamber 12 is delimited on the 'inside by the turbine housing outer wall
6 and on the outside by a reactor outer wall 18 cast onto the latter.
Ir; an alternative construct~on (not shown). the ammonia reactor 11 may be pre-manufactured
as a separate unit and then attached to the tilrbine housing 5. In this case, the ammonia reactor
11 has a closed housing which comprises the vaporization/hydrolysis chamber. At least
the inner wall of the reactor housing is made of corrosion-proof metallic material which is
resistant to high temperatures and is highly thermal conductive. This inner wall of the reactor
housing is exactly tailored to the external shape of the turbine housing outer wall 6, so that it
presses intimately against the turbine housing outer wall 6 in the installed position of the
ammonia reactor, preferably with contact.
Independently of the type of implementation of the ammonia reactor 11, its vaporizaiionlhydrolysis
chamber 12 is connected via a channel 19 (see Figure 3) to the exhaust gas
path before or at the intake of the turbine 2 of the exhaust gas turbocharger I . Via this channel
19, the vaporization/hydrolysis chamber 12 may be supplied with an exhaust gas partial
flow. \~hichis used both to in,zrease the temperature in the vaporization/hydrolysis chamber
12 and also as a source for ,water vapor, which is used for complete conversion of the isgcyanic
acid initially arising during the ammonia production into ammonia and carbon diox-
~de.
In the case of the examples shown in Figures 1 through 3, the channel 19 is implemented by
a hole in the inlet area 7 of the turbine housing, which discharges into the vaporizaiionlhydrolysis
chamber 12. In the above-mentioned alternative implementation of the ammonia
reactor 11, the channel 19 would be implemented via a pipeline,
The channel 19 may be implemented as a connection which is permanently permeable to a
specific exhaust gas partial quantity, but alternatively may also be implemented as a connection
which may be switched as needed for passage using 2 switching andlor throttle valve or
may also be regulated in regard to the flow quantity.
Ai the output, the vaporization/hydrolysis chamber 12 of the ammonia reactor 11 is connected
via at least one channel 20 to an exhaust gas line 10, 102 connected to the turbine
outlet 8. Via this channel or these channels 20, the ammonia produced in the ammonia reactor
11 or the gas mjxture containing this ammonia is transferable into the exhaust gas system
10, 10a.
In the exemplary embodimen: shown in Figure 2, a section 10 a of the exhaust gas line 1C
adjoins the outlet 8 of t h t~urb ine housins 5 in which - still close to the exhaust gas turbocharger
1 - an oxidation catalyst 21 used for NO - NO? conversion is installed.
This exhaust gas line section 10a having the installed oxidation catalyst 21 is enclosed externally
at a distance by a pipe 22, which also is connected to the outlet 8 of the turbine
housing 5, its front face 23 there. The at least one channel, here multiple channels 20; dlscharge
into this annular channei 24 thus resulting. In this case, the ammonia produced in the
ammonia reactor i 1 or the gas mixture containing it is accordingly fed into the annular channel
24, which then conducts it as a parallel flow past the oxidation catalyst 21 and feeds its
flow into the exhaust gas flow after the latter and then from there - mixed with the exhaust
gas enriched with NO2 - jeeds it to the SCR catalyst(s). The channels 20 are implemented as
holes which lead from the outer front face 23 of the turbine outlet 8 through the turbine housing
wall section enclosing the turbine outlet 8 into the vaporization/hydrolysis chamber 12.
The cross-section of the channel 20 or the entire cross-section of all channels 20 is dimensioned
in accordance with the conversion speed of the starting material used for ammonia
production - urea-water solution or solid urea - in such way that this conversion process into
ammonia may occur completely and witho~r~ets idile.
The wall delimiting the vaporization/hydrolysis chamber 12 may be provided internally with a
catalytic coating favoring the conversion of the urea, e.g., titanium dioxide (Ti02).
In addition, in the case of the examples shown in Figures 1 through 3, the outside of the iurbine
housing outer wall 6 may have ribs or other projecting structures - for the purpose of
increasing the heat-radiating area and thus the heat introduced into the vaporizationlhydrolysis
chamber 12.
To attach a nozzle used for feeding the urea-water solution or the end piece 25 of a pipe for
injecting solid urea prills (see Figure 4), a support 26 (see Figure 5) may be provided, which
is screwed into an attachment eye 27 provided externally on the ammonia reactor 11 and
accommodates the nozzle or the end piece 25 of the pipe 16 forming the injection channel.
As shown in Figure 5, the support 26 may have a plate 28 on its reactor-interior end. This
plate 28, which is flushed on all sides by the hoi exhaust gas, may form the first conversion
element for incident urea-water jets as a heating plate. In the case of solid urea, the plate 28
rnay be used as an impact plate, on which the injected urea prills may be smashed into multiple
extremely small particles as they hit it, which favor the conversion process into ammonia.
Using the ammonia reactor according to the p:resent invention situated around the turbine
housing, ii is possible to dispense with costly and bulky hydrolysis reactors. The ammonia
reactor itself only occupies a small amount of space, which is normally present in any case
around the turbine of an exhaust gas turbocharger or remains free. In addition, the ammonia
reactor according to the present invention may be implemented less expensively than a hydrolysis
reactor in the final effect,

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Patent Number

271200

Indian Patent Application Number

2072/DEL/2006

PG Journal Number

07/2016

Publication Date

12-Feb-2016

Grant Date

09-Feb-2016

Date of Filing

20-Sep-2006

Name of Patentee

MAN TRUCK & BUS AG

Applicant Address

POSTFACH 50 06 20, 80976 MUNCHEN, GERMANY.

Inventors:

#	Inventor's Name	Inventor's Address
1	ERWIN, STIERMANN	HOHENSTR. 14A, 86356 NEUSAß, GERMANY.

PCT International Classification Number

F01L1/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	10 2005 045 029.6	2005-09-22	Germany