FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
1. Title of the Invention
TURBOCHARGER
2. Applicant(s)
Name Nationality Address
FRAUNHOFER-GESELLSCHAFT ZUR
FÖRDERUNG DER ANGEWANDTEN
FORSCHUNG E.V.
GERMAN Hansastraße 27c 80686 München,
Germany
3. Preamble to the description
The following specification particularly describes the invention and the manner in which it is to be performed
2
The invention relates to a turbocharger with a compressor arrangement which is
configured to compress the fresh air of an internal combustion engine, comprising at
least one compressor housing with a fresh air inlet and a fresh air outlet, at least one
5 compressor impeller being arranged in the compressor housing, and with at least one
exhaust gas turbine for driving the compressor arrangement, with at least one turbine
housing with an exhaust gas inlet and an exhaust gas outlet, at least one turbine wheel
being arranged in the turbine housing.
10 It is known in practice to equip an internal combustion engine with at least one
turbocharger. The turbocharger contains a turbine which extracts kinetic energy from
the exhaust gas flow and provides it as mechanical power. This mechanical power is
used to drive a compressor arrangement by means of which the fresh air required for
combustion can be supplied to the internal combustion engine at increased pressure.
15 This can optimize the response characteristic, the output and/or the consumption.
It is also known in practice to supply the exhaust gases from an internal combustion
engine to at least one exhaust gas aftertreatment device. The exhaust gas aftertreatment
device can, for example, contain a particulate filter and/or at least one catalytic
20 converter. This can retain soot particles or oxidize or reduce pollutants, such as CO,
CHx or NOx, thus rendering them harmless.
All known catalytic converters require an operating temperature higher than normal
ambient conditions in order to remove pollutants from the exhaust gas to a significant
25 extent. Although a particulate filter works reliably even after a cold start, it has to be
regenerated from time to time at an elevated temperature.
Therefore, WO 2020/193595 A1 discloses a heated catalytic converter which is
designed to convert supplied fuel with exhaust gas or fresh air. The heated catalytic
30 converter can be operated in different operating states. For example, the supplied fuel
can simply be vaporized in order to be oxidized at an exhaust gas aftertreatment device,
as a result of which heat is released and the exhaust gas aftertreatment device is heated
up. In other operating states, at least some of the fuel can be converted into a synthesis
3
gas, which has a lower light-off temperature at the exhaust gas aftertreatment device and
thus renders possible better heating of the exhaust gas aftertreatment device in some
operating states of the internal combustion engine. Finally, the fuel can be completely
5 converted in the heated catalytic converter in order to thus generate a hot gas which is
supplied to the exhaust gas aftertreatment device and heats it up.
The disadvantage of this known heated catalytic converter is that it requires additional
installation space which can be particularly limited in passenger cars and lightweight
10 commercial vehicles.
On the basis of the prior art, this object of the invention is therefore to provide a device
for rapidly heating an exhaust gas aftertreatment device of an internal combustion
engine, which requires little installation space and is also suitable for retrofitting
15 existing internal combustion engines.
According to the invention, the object is achieved by a turbocharger according to claim
1. Advantageous further developments of the invention are found in the subclaims.
20 According to the invention, a turbocharger is proposed which has at least one
compressor arrangement and at least one exhaust gas turbine. The compressor
arrangement is designed to compress the fresh air to be supplied to an internal
combustion engine. For this purpose, the compressor arrangement contains at least one
compressor housing having a fresh air inlet and a fresh air outlet, at least one
25 compressor impeller being arranged in the compressor housing. The fresh air required
for the combustion of the fuel in the internal combustion engine is supplied to the
compressor arrangement through the fresh air inlet at a first pressure and leaves the
fresh air outlet at a second pressure, the second pressure being higher than the first
pressure. Therefore, the compressor arrangement adds mechanical work to the fresh air.
30
The at least one compressor impeller can have a plurality of rotor blades and operate as
a radial compressor or axial compressor. In other embodiments of the invention, the at
least one compressor impeller can be part of a screw compressor or a Roots blower or a
4
swash plate compressor. The invention does not teach the use of a particular design of
compressor arrangement as a solution principle.
5 The at least one exhaust gas turbine is designed to drive the compressor arrangement.
For this purpose, the exhaust gas turbine on the one hand and the compressor
arrangement on the other hand can be connected to each other by a rotating shaft, a
gearbox, a belt drive or in another manner known per se. The at least one exhaust gas
turbine has at least one turbine housing having an exhaust gas inlet and an exhaust gas
10 outlet, at least one turbine wheel being arranged in the turbine housing. The exhaust gas
turbine is designed to extract energy from the exhaust gas flow and provide it as
mechanical power. In this respect, an exhaust gas flow from the internal combustion
engine is supplied to the turbine housing at a second pressure via the exhaust gas inlet
and discharged at a first pressure via the exhaust gas outlet, the second pressure being
15 higher than the first pressure.
The turbocharger according to the invention also has a heated catalytic converter which
is designed to at least partially convert supplied fuel with fresh air and/or exhaust gas,
the heated catalytic converter containing a catalytic converter housing having at least
20 one gas inlet and at least one gas outlet and at least one fuel inlet. Fresh air and/or
exhaust gas is supplied via the gas inlet. Fuel, for example gasoline or diesel, is supplied
to the heated catalytic converter via the fuel inlet. A product gas is produced in the
heated catalytic converter from fuel and exhaust gas and/or fresh air. For this purpose,
the fuel is vaporized in the heated catalytic converter and/or at least partially oxidized
25 with the release of heat and/or converted into a synthesis gas via cracking reactions. The
product gas thus contains a hot gas and/or fuel vapor and/or synthesis gas. The product
gas leaves the heated catalytic converter via the gas outlet and is supplied back into the
exhaust pipe downstream of the exhaust gas turbine. Therefore, the turbulence
generated by the exhaust gas turbine can be used to mix the product gas produced in the
30 heated catalytic converter with the exhaust gas. Exhaust gas and/or fresh air can be
supplied at the respective second pressure via the gas inlet and discharged into the
exhaust gas flowing at the first pressure, resulting in a reliable flow through the catalytic
converter housing without an additional conveying device. In some embodiments of the
5
invention, the heated catalytic converter is designed to vaporize supplied fuel by means
of a fleece without coking.
5 According to the invention, it is now proposed that the catalytic converter housing on
the one hand and the compressor housing and/or the turbine housing on the other hand
are in thermal contact on at least one part surface. On the one hand, this leads to a
compact design since the turbocharger with integrated heated catalytic converter
requires hardly any more installation space than a known turbocharger without the
10 additional functionality of a heated catalytic converter. In addition, internal combustion
engines having a turbocharger and being already in use can be easily retrofitted with the
heating device according to the invention by replacing the existing turbocharger with
the turbocharger according to the invention. In this way, additional thermal energy can
be introduced into an exhaust gas aftertreatment device without reducing the efficiency
15 of the internal combustion engine through in-engine measures.
Furthermore, the waste heat generated during the operation of the turbocharger can be
supplied to the heated catalytic converter so that the heated catalytic converter itself
reaches operating temperature more quickly. As a result, the supply of electrical
20 auxiliary energy to the heated catalytic converter can be reduced or completely avoided
so that the heated catalytic converter can be operated in a consumption-optimized
manner.
In some embodiments of the invention, the turbocharger further contains a first
25 overflow channel having a first end and an opposite second end, the first end being
connected to the exhaust gas inlet of the turbine housing and the second end being
connected to the gas inlet of the catalytic converter housing. This makes it possible to
supply the heated catalytic converter with exhaust gas which on the one hand introduces
thermal energy into the heated catalytic converter in order to render possible or promote
30 the conversion of the fuel at the catalytic converter in this way or to vaporize fuel, i.e. to
convert it from the liquid to the gaseous state. In addition, the exhaust gas can be used
as an oxidizing agent to oxidize at least part of the fuel and thus release heat. Oxygenrich exhaust gas is particularly suitable for this purpose and is produced, for example,
6
during lean operation (air number  > 1) of a spark-ignition internal combustion engine
or generally in the case of self-igniting internal combustion engines.
5 In some embodiments of the invention, the turbocharger can include at least one second
overflow channel having a first end and an opposite second end, the first end being
connected to the fresh air outlet of the compressor housing and the second end being
connected to the gas inlet of the catalytic converter housing. The second overflow
channel is thus used to supply fresh air to the heated catalytic converter. Just like the
10 exhaust gas, the compressed fresh air can also be used to add additional thermal energy
to the heated catalytic converter. Furthermore, the fresh air is suitable as an oxidizing
agent for the fuel supplied to the heated catalytic converter. In this way, oxidation of the
fuel can be ensured independently of the operating state of the internal combustion
engine since oxidation can take place independently of the composition of the raw
15 exhaust gas.
In some embodiments of the invention, the turbocharger can contain a third overflow
channel which has a first end and an opposite second end, the first end being connected
to the gas outlet of the catalytic converter housing and the second end being connected
20 to the exhaust gas outlet of the turbine housing. The third overflow channel is thus
suitable and intended for supplying the product gas generated in the heated catalytic
converter downstream of the exhaust gas turbine to the exhaust pipe. As already
described above, the product gas may be or contain a fuel vapor. In other embodiments
of the invention, the product gas may be or contain a synthesis gas obtained by reacting
25 the fuel on the heated catalytic converter. In yet other embodiments of the invention, the
product gas may be a hot gas or contain a hot gas obtained by oxidizing the fuel on the
heated catalytic converter. Since the heated catalytic converter is thus supplied with
exhaust gas or fresh air at a comparatively high pressure level upstream of the exhaust
gas turbine and the product gas of the heated catalytic converter is supplied at a lower
30 pressure downstream of the exhaust gas turbine, the pressure drop within the exhaust
gas turbine inevitably results in a flow of exhaust gas or fresh air through the heated
catalytic converter.
7
It goes without saying that the first, second or third overflow channel need not be
present in all embodiments of the invention. In some embodiments of the invention,
there may be only one or only two of these overflow channels.
5
In some embodiments of the invention, the first overflow channel and/or the second
overflow channel and/or the third overflow channel may be designed, at least in
sections, as a bore in the catalytic converter housing or in the compressor housing or in
the turbine housing. A bore of this type can be created either by machining or during the
10 primary forming of the housing. On the one hand, this results in a simple production of
the turbocharger according to the invention and a mechanically robust operation, as
there is no need for wear-prone plastics or rubber hoses as well as connection points for
hoses to the housing.
15 In some embodiments of the invention, at least one nozzle can be arranged on the
second end of the third overflow channel. This allows the product gas of the heated
catalytic converter to be introduced into the exhaust gas flow with a predeterminable
direction and/or a predeterminable pulse so that the mixing of the product gas with the
exhaust gas flow is additionally promoted.
20
In some embodiments of the invention, a two-way valve may be provided in the first
overflow channel and/or in the second overflow channel and/or in the third overflow
channel. A two-way valve of this type can be influenced by an electrical signal from a
control device so that the flow in the respective overflow channel can be controlled in
25 open-loop or closed-loop fashion. As a result, depending on the operating state, exhaust
gas or fresh air or a mixture of exhaust gas and fresh air can be supplied to the heated
catalytic converter or the heated catalytic converter can be completely deactivated by
closing at least one overflow channel. In some embodiments of the invention, the
overflow channels can be used as a wastegate valve by discharging impermissibly high
30 boost pressure through the heated catalytic converter into the exhaust line or by
bypassing exhaust gas past the exhaust gas turbine. An additional wastegate valve can
thus be dispensed with.
8
In some embodiments of the invention, the turbocharger can further contain a three-way
valve which has three inlets/outlets to which the first overflow channel and the second
overflow channel and the gas inlet are connected. The position of the three-way valve
5 can be used to supply the heated catalytic converter with fresh air or exhaust gas or a
mixture of fresh air and exhaust gas so that the operating state of the heated catalytic
converter can be adjusted over a wide range using a single valve. By closing the threeway valve, the heated catalytic converter can be taken out of operation, for example at
full load or operating conditions close to full load, which do not require any additional
10 heating measures for the exhaust gas aftertreatment.
In one embodiment of the invention, at least part of the catalytic converter housing and
either the compressor housing or the turbine housing can be manufactured in one piece.
A one-piece production of this type can be achieved in particular by primary forming in
15 a casting method. In other embodiments of the invention, the housings can be
manufactured at least partially in a 3D printing method. In this way, at least one part of
the catalytic converter housing and at least one part of the compressor housing or of the
turbine housing can be integrally bonded so that heat from the compressor housing or
the turbine housing can be introduced into the heated catalytic converter with little loss.
20 In this way, it is possible to avoid raw contact surfaces and/or contact surfaces oxidized
after prolonged operation which have a comparatively high heat input resistance.
In some embodiments of the invention, at least a part of the catalytic converter housing
and at least a part of the compressor housing and at least a part of the turbine housing
25 can be manufactured in one piece. This results in a mechanically robust and compact
design of the entire turbocharger.
In some embodiments of the invention, a heat flow of about 0.5 kW to about 6 kW can
be introduced into the heated catalytic converter due to the thermal contact between the
30 catalytic converter housing on the one hand and the compressor housing or the turbine
housing on the other hand. In other embodiments of the invention, the heat flow
introduced into the heated catalytic converter by the thermal contact can be between
about 1 kW and about 4 kW. In yet other embodiments of the invention, the heat input
9
can be between about 0.5 kW and about 3 kW. The above mentioned heat outputs
permit the efficient vaporization and/or conversion of fuel in the heated catalytic
converter without additional electrical auxiliary energy. The internal combustion engine
5 can therefore be operated in a consumption-optimized manner.
The invention shall be explained in more detail below on the basis of drawings without
limiting the general concept of the invention. Here,
10 Figure 1 shows a first view of a first embodiment of the turbocharger according to
the invention.
Figure 2 shows a second view of the first embodiment of the turbocharger according
to the invention.
15
Figure 3 shows a third view of the first embodiment of the turbocharger according to
the invention.
Figure 4 shows a first view of a second embodiment of the turbocharger according to
20 the invention.
Figure 5 shows a second view of the second embodiment of the turbocharger
according to the invention.
25 Figure 6 shows a block diagram of an internal combustion engine having an exhaust
gas aftertreatment device and a turbocharger according to the invention.
Figures 1 to 3 illustrate a first embodiment of the turbocharger according to the
invention. The turbocharger 1 contains a compressor arrangement 2, which is designed
30 to compress the fresh air required for combustion in an internal combustion engine. In
the illustrated exemplary embodiment, the compressor arrangement 2 is designed as a
radial compressor. The compressor arrangement 2 has a fresh air inlet 201, which is
designed to draw in ambient air at a first pressure. Furthermore, the compressor
10
arrangement 2 has a fresh air outlet 202, which is designed to discharge the compressed
fresh air at a second pressure. The fresh air outlet 202 can then be connected to the
intake manifold of an internal combustion engine and supply the fresh air required for
5 the combustion of the fuel in the internal combustion engine to the internal combustion
engine at increased pressure.
An exhaust gas turbine 3 having at least one turbine housing 30 is used to drive the
compressor arrangement. The turbine housing 30 has an exhaust gas inlet 301 and an
10 exhaust gas outlet 302, at least one turbine wheel being arranged in the turbine housing
30. In the illustrated exemplary embodiment, the exhaust gas turbine is also designed as
a radial turbine, i.e. the exhaust gas inlet 301 and the exhaust gas outlet 302 are
arranged approximately at right angles to one another.
15 In some embodiments of the invention, the turbine housing 30 and the compressor
housing 20 can be manufactured in one piece, for example as a cast part or in a 3D
printing method. In other embodiments of the invention, the housings can be made in
several parts or be separated and connected to one another by means of screw
connections.
20
Figures 1 to 3 also show a heated catalytic converter 4. The heated catalytic converter 4
has a housing 40 having a roughly cylindrical main shape. A gas inlet 401 is located on
the underside of the housing 4, through which exhaust gas and/or fresh air can be
supplied to the heated catalytic converter 4. Furthermore, the heated catalytic converter
25 4 has at least one fuel inlet 403. A gaseous or liquid fuel, usually gasoline or diesel, can
be supplied via the fuel inlet 403. The fuel can be completely or partially converted in
the above described manner with the exhaust gas or fresh air supplied via the gas inlet
401. The product gas generated in the heated catalytic converter 4 in this way leaves the
heated catalytic converter 4 via the gas outlet 402.
30
Furthermore, figures 1 to 3 show a holding bracket 43, which can be made of a
thermally conductive material, for example a metal or an alloy. The holding bracket is
designed to mechanically fix the catalytic converter housing 40 of the heated catalytic
11
converter 4. One end of the holding bracket 43 facing away from the catalytic converter
housing 40 is in mechanical and thermally conductive contact with the turbine housing
30. During operation of the turbocharger, hot exhaust gas flows through the turbine
5 housing 30. This causes the turbine housing 30 to heat up. Some of the heat is released
into the environment by convection and radiation. However, some of the heat
introduced into the turbine housing 30 flows into the heated catalytic converter 4 via the
holding bracket 43 and the part surface 45 formed between the catalytic converter
housing 40 and the holding bracket 43. For this purpose, the catalytic converter housing
10 40 can be made at least partially from a thermally conductive material, for example a
metal or an alloy. In this way, the heated catalytic converter 4 can be brought without or
with a reduced supply of electrical auxiliary energy to an increased temperature, at
which the fuel can be converted with fresh air or exhaust gas.
15 As can also be seen in the drawings, the catalytic converter housing 40 can also have
further ports 41. Temperature sensors or electrical heating devices can be connected via
these ports. Optionally, more than one fuel inlet 403 can be provided to render possible
a more homogeneous distribution of the fuel within the heated catalytic converter 4.
20 As further shown in figures 1and 2, the turbocharger according to the present invention
also contains a first overflow passage 15 having a first end 151 and a second end 152.
The first end 151 is connected to the exhaust gas inlet 301 of the turbine housing 30. In
this way, the exhaust gas flow leaving the internal combustion engine at a
comparatively high pressure, for example about 3.5 to about 5 bar, can be at least
25 partially extracted and supplied to the heated catalytic converter 4. For this purpose, the
second end 152 of the first overflow channel 15 is connected to the gas inlet 401 of the
catalytic converter housing 40. An optional two-way valve (not shown in the drawings)
can be located in the overflow channel 15, by means of which valve the amount of
exhaust gas supplied to the heated catalytic converter 4 can be controlled.
30
Furthermore, the turbocharger according to the first embodiment of the invention
includes a third overflow channel 35 having a first end 351 and an opposite second end
352. The first end 351 is here connected to the gas outlet 402 of the catalytic converter
12
housing 40. The second end 352 opens with an optional nozzle 353 downstream of the
turbine wheel in the turbine housing 30. Downstream of the turbine wheel, a lower
pressure is created on the one hand, since the turbine wheel draws energy from the
5 exhaust gas flow. In addition, the turbine wheel causes turbulence and therefore good
mixing of the product gas generated in the heated catalytic converter 4 with the main
exhaust gas flow. The pressure difference results in a defined flow of exhaust gas
through the heated catalytic converter 4. At the same time, the turbocharger according
to the invention has a compact design, which saves installation space and makes it easy
10 to retrofit existing internal combustion engines.
Figures 4 and 5 illustrate a second embodiment of the invention in more detail. Identical
components of the invention are provided with identical reference signs so that the
following description is limited to the essential differences of the invention.
15
As is clear from figure 4, the second embodiment dispenses with a holding bracket 43
for the mechanical and thermal coupling of the turbine housing 30 and the catalytic
converter housing 40. According to the second embodiment, the catalytic converter
housing 40 is designed in two parts with a lower part 422 and an upper part 421. In the
20 illustrated exemplary embodiment, the lower part 422 of the catalytic converter housing
40 is manufactured in one piece together with the turbine housing 30, i.e. during the
primary forming of the turbine housing 30 in a metal casting method, the lower part 422
is also manufactured in the same method step as a homogeneous component of the
turbine housing 30.
25
Due to the one-piece or monolithic production of the lower part 422 of the catalytic
converter housing 40 and the turbine housing 30, there is no interface at the part surface
45, which causes thermal coupling of the two components and impedes heat input due
to unevenness, contamination or oxidation. The heat input from the turbine housing 30
30 to the catalytic converter housing 40 can therefore be more homogeneous and/or more
effective. In other embodiments of the invention, such an integrally bonded connection
of at least one part of the catalytic converter housing and the turbine housing can also be
achieved by soldering, welding or 3D printing.
13
In the case of the monolithic production according to the second embodiment of the
invention, the overflow channels 15, 25 and 35 can also be produced in a simple manner
5 by recesses or bores in the housing. In addition, two-way or three-way valves can also
be integrated into the housing and can influence the supply of exhaust gas or fresh air
on the one hand and the removal of product gas on the other hand in order to adapt the
operating parameters of the heated catalytic converter 4 to predeterminable target
conditions.
10
Figure 6 shows a block diagram of an internal combustion engine 7 having an exhaust
gas aftertreatment device 72, 73 and 74 and a turbocharger according to the invention.
For reasons of clarity, the compressor arrangement 2, the exhaust gas turbine 3 and the
heated catalytic converter 4 are spatially separated in figure 6. A person skilled in the art
15 is of course aware that these components of the invention work together, as described
above with reference to figures 1 to 5.
The internal combustion engine 7 can be a self-ignition or spark-ignition internal
combustion engine. The internal combustion engine 7 is designed to provide mechanical
20 power by burning fuel with ambient air. The internal combustion engine 7 can be used
in a car, a truck, a ship, a construction machine or in stationary fashion in a compressor,
a generator, a combined heat and power unit or a similar device.
During operation, the internal combustion engine 7 is supplied with fresh or ambient air
25 via an air filter 77. The fresh air is brought to a higher pressure level in the compressor
arrangement 2. For this purpose, the fresh air is supplied to the fresh air inlet 201,
compressed with a compressor impeller and then supplied to the internal combustion
engine 7 via the fresh air outlet 202.
30 The compressor arrangement is driven by a rotating shaft 8, the drive power of which is
provided by an exhaust gas turbine 3. For this purpose, the exhaust gas from the internal
combustion engine 7 is supplied into the exhaust gas turbine via the exhaust gas inlet
14
301. The exhaust gas then leaves the exhaust gas turbine 3 via an exhaust gas outlet
302.
5 The exhaust gas is then supplied via an exhaust pipe 71 to an exhaust gas aftertreatment
device, which can reduce soot particles and gaseous pollutants. In the illustrated
exemplary embodiment, the exhaust gas aftertreatment device contains an oxidation
catalytic converter 72, which is designed to oxidize hydrocarbons and carbon monoxide.
The exhaust gas pre-treated in this way reaches a particulate filter 73, which retains fine
10 dust particles. The exhaust gas is then supplied into an SCR catalytic converter 74,
which reduces nitrogen oxides with the addition of urea. Exhaust gas temperatures can
be measured at different points using various temperature sensors TIA to control the
heated catalytic converter 4 and the internal combustion engine 7 in an open-loop or
closed-loop fashion.
15
The oxidation catalytic converter 72 and the SCR catalytic converter 74 require elevated
temperatures of more than 250°C, for example, in order to operate. The particulate filter
73 is also functional at low temperatures, but must be operated at elevated temperatures
from time to time in order to oxidize embedded particles and regenerate the particulate
20 filter in this way. There is therefore a need to bring the exhaust gas flowing in the
exhaust pipe 71 to predeterminable temperatures or to keep it at elevated temperatures.
According to the prior art, this can be achieved by appropriate operating conditions of
the internal combustion engine 7, for example by late or post-injection. However, this
worsens the exhaust gas behavior and increases the fuel requirement of the internal
25 combustion engine 7.
According to the invention, it is therefore proposed to use a heated catalytic converter 4
which is designed to introduce heat into at least one component 72, 73, 74 of the
exhaust gas aftertreatment device. For this purpose, fuel is supplied to the heated
30 catalytic converter 4 from a storage tank 74 via an electrically driven pump 46, which
fuel enters the catalytic converter housing 40 of the heated catalytic converter 4 via a
fuel inlet 403. A catalytic converter support, which is coated with a catalyst material, is
arranged inside the catalytic converter housing 4.
15
In the simplest case, the fuel entering via the fuel inlet 403 can be vaporized in the
heated catalytic converter 4 and leave the catalytic converter housing 4 via the gas outlet
5 402. By means of a third overflow channel 35 having a first end 351 and an opposite
second end 352, this fuel vapor can be introduced into the exhaust pipe 71, the
turbulence generated by the exhaust gas turbine 3 ensuring effective mixing. The fuel
vapor can then be oxidized at the oxidation catalyst 72 and/or a downstream component
73 or 74, where it releases heat.
10
In other operating states, the fuel can be converted in the heated catalytic converter 4
with exhaust gas and/or fresh air so that either a hot gas or a synthesis gas is formed,
which can be supplied to the exhaust pipe 71 via the third overflow channel 35 in the
same way. A synthesis gas can also be converted at the oxidation catalytic converter 72
15 or a downstream component 73, 74, it being possible that the light-off temperature is
reduced compared to vaporized but chemically unchanged fuel.
In order to convert the fuel with exhaust gas or fresh air, the heated catalytic converter 4
also contains a gas inlet 401. The gas inlet 401 is connected via a three-way valve 53 to
20 a first overflow channel 15 and a second overflow channel 25. The first overflow
channel 15 is connected via its first end 151 to the gas inlet 301 of the exhaust gas
turbine 3 so that exhaust gas can be extracted at a comparatively high pressure level and
supplied to a port of the three-way valve 53. Furthermore, the illustrated embodiment
contains a second overflow channel 25, the first end 251 of which is connected to the
25 fresh air outlet 202 of the compressor arrangement 2. The opposite second end 252 is
connected to a further port of the three-way valve 53. Depending on the position of the
three-way valve 53, fresh air or exhaust gas or both can thus be supplied into the
catalytic converter housing 40 of the heated catalytic converter 4 via the gas inlet 401.
The oxygen content in the heated catalytic converter 4 can thus be adjusted by the
30 position of the three-way valve 53 so that the type of conversion of the supplied fuel can
be influenced.
16
Both the conversion of the fuel in the heated catalytic converter 4 and the mere
vaporization require thermal energy which can, on the one hand, can be generated by at
least partial oxidation of the fuel in the heated catalytic converter 4. In addition,
5 however, this energy can also be realized according to the invention by thermal
coupling of the heated catalytic converter 4 to the exhaust gas turbine 3 and/or the
compressor arrangement 2.
An electronic open-loop or closed-loop control device 76 is available for driving the
10 amount of fuel supplied and the three-way valve 53 and, if necessary, further
components of the heated catalytic converter 4. This device can optionally be connected
to the engine control unit 75 via a data bus so that the operating conditions of the
internal combustion engine 7 can also be taken into account when driving the heated
catalytic converter 4.
15
The complete integration of the heated catalytic converter 4 into the exhaust gas
turbocharger also makes it possible to save on additional components. In the illustrated
exemplary embodiment, the three-way valve 53 can also be used to replace a wastegate
valve. For this purpose, if the pressure at the fresh air outlet 202 rises unacceptably, the
20 fuel supply to the heated catalytic converter 4 can be interrupted and the three-way
valve 53 can be opened so that exhaust gas flows through the heated catalytic converter
4 from the high-pressure side of the exhaust gas turbine 3 to the low-pressure side
without generating additional heat.
25 Of course, the invention is not limited to the illustrated embodiments. Therefore, the
above description should not be regarded as restrictive but as explanatory. The
following claims are to be understood in such a way that a stated feature is present in at
least one embodiment of the invention. This does not exclude the presence of further
features. If the claims and the above description define "first" and "second"
30 embodiments, this designation is used to distinguish between two similar embodiments
without determining a ranking order

WE CLAIM:
1. Turbocharger (1) with
5 a compressor arrangement (2) which is configured to compress the fresh air
of an internal combustion engine, comprising at least one compressor housing
(20) with a fresh air inlet (201) and a fresh air outlet (202), at least one
compressor impeller being arranged in the compressor housing (20), and
with at least one exhaust gas turbine (3) for driving the compressor
10 arrangement (2), with at least one turbine housing (30) with an exhaust gas inlet
(301) and an exhaust gas outlet (302), at least one turbine wheel being arranged in
the turbine housing (30),
characterized in that
the turbocharger (1), furthermore, comprises a heated catalytic converter (4)
15 which is configured to at least partially convert supplied fuel with fresh air and/or
exhaust gas, the heated catalytic converter (4) containing a catalytic converter
housing (40) with a gas inlet (401) and a gas outlet (402) and a fuel inlet (403),
wherein
firstly the catalytic converter housing (40) and secondly the compressor
20 housing (20) and/or the turbine housing (30) are in thermal contact on at least one
part surface (45).
2. Turbocharger according to claim 1, further comprising a first overflow channel
(15) having a first end (151) and an opposite second end (152), wherein the first
25 end (151) is connected to the exhaust gas inlet (301) of the turbine housing (30)
and the second end (152) is connected to the gas inlet (401) of the catalytic
converter housing (40).
3. Turbocharger according to any one of claims 1 to 2, further comprising a second
30 overflow channel (25) having a first end (251) and an opposite second end (252),
wherein the first end (251) is connected to the fresh air outlet (202) of the
compressor housing (20) and the second end (252) is connected to the gas inlet
(401) of the catalytic converter housing (40).
18
4. Turbocharger according to any one of claims 1 to 3, further comprising a third
overflow channel (35) having a first end (351) and an opposite second end (352),
5 wherein the first end (351) is connected to the gas outlet (402) of the catalytic
converter housing (40) and the second end (352) is connected to the exhaust gas
outlet (302) of the turbine housing (30).
5. Turbocharger according to claim 4, characterized in that at least one nozzle (353)
10 is arranged on the second end (352) of the third overflow channel (35).
6. Turbocharger according to any one of claims 2 to 5, characterized in that a 2-way
valve (52) is present in the first overflow channel (15) and/or in the second
overflow channel (25) and/or in the third overflow channel (35).
15
7. Turbocharger according to any one of claims 1 to 6, further comprising a 3-way
valve (53) with three inlets/outlets, to which the first overflow channel (15) and
the second overflow channel (25) and the gas inlet (401) are connected.
20 8. Turbocharger according to any one of claims 1 to 7, characterized in that at least
one part (421, 422) of the catalytic converter housing (40) and either the
compressor housing (20) or the turbine housing (30) are manufactured in one
piece.
25 9. Turbocharger according to any one of claims 1 to 7, characterized in that at least
one part (42) of the catalytic converter housing (40) and the compressor housing
(20) and the turbine housing (30) are manufactured in one piece.
10. Turbocharger according to claim 8 or 9, characterized in that the first overflow
30 channel (15) and/or the second overflow channel (25) and/or the third overflow
channel (35) is designed at least in sections as a bore in the catalytic converter
housing (40) and/or in the compressor housing (20) and/or in the turbine housing
(30).
19
11. Turbocharger according to any one of claims 1 to 10, characterized in that a heat
flow of about 0.5 kW to about 6 kW or of about 1 kW to about 4 kW or of about
5 0.5 kW to about 3 kW can be introduced into the catalytic converter housing (40)
by the thermal contact between the catalytic converter housing (40) on the one
hand and the compressor housing (20) and/or the turbine housing (30) on the other
hand when exhaust gas flows through the turbine housing (30).
10 12. Turbocharger according to any one of claims 8 to 10, characterized in that the
catalytic converter housing (40) and at least either the compressor housing (20) or
the turbine housing (30) are manufactured as a cast part.
13. Method for modifying an internal combustion engine with a turbocharger,
15 comprising the following method steps:
removal of the existing turbocharger and
installation of a turbocharger according to any one of claims 1 to 12.