U.S. patent application number 12/451974 was filed with the patent office on 2010-07-22 for drive train, particularly for trucks and rail vehicles.
Invention is credited to Stephan Bartosch, Jurgen Berger.
Application Number | 20100180584 12/451974 |
Document ID | / |
Family ID | 40185030 |
Filed Date | 2010-07-22 |
United States Patent
Application |
20100180584 |
Kind Code |
A1 |
Berger; Jurgen ; et
al. |
July 22, 2010 |
DRIVE TRAIN, PARTICULARLY FOR TRUCKS AND RAIL VEHICLES
Abstract
The invention relates to a drive train, especially for a
commercial vehicle, with an internal combustion engine which
produces an exhaust gas stream; with an exhaust gas line which is
connected to the internal combustion engine; with a supply air line
system for supplying a supply air flow for combustion in the
internal combustion engine, which supply air line system is
connected to the internal combustion engine; with a steam cycle,
comprising an expansion machine, at least one heat exchanger in
order to evaporate the working medium of the steam cycle, and a
condenser; the supply air line system comprises a fresh air line
for supplying a fresh air flow for combustion in the internal
combustion engine and a recirculating line for recirculating a part
of the exhaust gas stream to the fresh air side for combustion in
the internal combustion engine. The invention is characterized in
that a plurality of heat exchangers for evaporation of the working
medium of the steam cycle is provided in the recirculating line,
and a further heat exchanger for evaporation of the working medium
of the steam cycle is provided in the exhaust gas line which is
supplied with an exhaust gas stream intended for being conducted to
the ambient environment, and the working medium of the steam cycle
is first conducted through a second heat exchanger in the
recirculating line, then through the further heat exchanger in the
exhaust gas line and then through a first heat exchanger in the
recirculating line, with the recirculated part of the exhaust gas
stream first being conducted through the first heat exchanger and
then through the second heat exchanger, and is then cooled.
Inventors: |
Berger; Jurgen; (Gerstetten,
DE) ; Bartosch; Stephan; (Rammingen, DE) |
Correspondence
Address: |
FARJAMI & FARJAMI LLP
26522 LA ALAMEDA AVENUE, SUITE 360
MISSION VIEJO
CA
92691
US
|
Family ID: |
40185030 |
Appl. No.: |
12/451974 |
Filed: |
October 22, 2008 |
PCT Filed: |
October 22, 2008 |
PCT NO: |
PCT/EP2008/008918 |
371 Date: |
March 29, 2010 |
Current U.S.
Class: |
60/320 ;
60/670 |
Current CPC
Class: |
F02B 33/32 20130101;
F01N 3/021 20130101; F01N 5/02 20130101; F02M 26/24 20160201; F02B
37/00 20130101; F02B 37/013 20130101; F02B 41/10 20130101; Y02E
20/14 20130101; Y02T 10/12 20130101; F02M 26/28 20160201; Y02T
10/166 20130101; Y02T 10/16 20130101; Y02T 10/144 20130101; F02B
37/105 20130101; F01N 13/009 20140601; F02B 29/0425 20130101; F01N
2240/02 20130101; F02B 39/12 20130101; F02G 5/04 20130101; Y02T
10/146 20130101; Y02T 10/163 20130101 |
Class at
Publication: |
60/320 ;
60/670 |
International
Class: |
F01N 5/02 20060101
F01N005/02; F01K 23/06 20060101 F01K023/06 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 30, 2007 |
DE |
10 2007 052 117.2 |
Claims
1-9. (canceled)
10. A drive train, especially for a commercial vehicle, with an
internal combustion engine which produces an exhaust gas stream;
with an exhaust gas line which is connected to the internal
combustion engine; with a supply air line system for supplying a
supply air flow for combustion in the internal combustion engine,
which supply air line system is connected to the internal
combustion engine; with a steam cycle, comprising an expansion
machine, at least one heat exchanger in order to evaporate the
working medium of the steam cycle, and a condenser; the supply air
line system comprises a fresh air line for supplying a fresh air
flow for combustion in the internal combustion engine and a
recirculating line for recirculating a part of the exhaust gas
stream to the fresh air side for combustion in the internal
combustion engine; characterized in that a plurality of heat
exchangers for evaporation of the working medium of the steam cycle
is provided in the recirculating line, and a further heat exchanger
for evaporation of the working medium of the steam cycle in the
exhaust gas line which is supplied with an exhaust gas stream
intended for being conducted to the ambient environment, and the
working medium of the steam cycle is first conducted through a
second heat exchanger in the recirculating line, then through the
further heat exchanger in the exhaust gas line and then through a
first heat exchanger in the recirculating line, with the
recirculated part of the exhaust gas stream first being conducted
through the first heat exchanger and then through the second heat
exchanger, and is thereby cooled.
11. A drive train according to claim 10, characterized in that in
the supply air line system a compressor is arranged which is
especially driven by an exhaust gas turbine, in the exhaust gas
stream and which especially compresses fresh air supplied to the
internal combustion engine for combustion, and a heat exchanger is
arranged in the supply air line system in the direction of flow
behind the compressor and is supplied with the compressed supply
air or a mixture of compressed supply air and recirculated exhaust
gas stream and extracts heat from the same for evaporating the
working medium of the steam cycle.
12. A drive train according to claim 11, characterized in that
several compressors or a multi-stage compressor is provided in the
supply air line system, and the heat exchanger is arranged in the
direction of flow between the compressors or compressor stages, or
one heat exchanger each is arranged in the direction of flow behind
one and especially behind each compressor.
13. A drive train according to claim 10, characterized in that
following the heat exchanger in the recirculating line or the
second heat exchanger the recirculated part of the exhaust gas
stream is conducted and cooled by a heat exchanger embedded in a
cooling cycle, especially a vehicle cooling cycle.
14. A drive train according to claim 11, characterized in that
following the heat exchanger in the recirculating line or the
second heat exchanger the recirculated part of the exhaust gas
stream is conducted and cooled by a heat exchanger embedded in a
cooling cycle, especially a vehicle cooling cycle.
15. A drive train according to claim 12, characterized in that
following the heat exchanger in the recirculating line or the
second heat exchanger the recirculated part of the exhaust gas
stream is conducted and cooled by a heat exchanger embedded in a
cooling cycle, especially a vehicle cooling cycle.
16. A drive train according to claim 10, characterized in that an
exhaust gas turbine is arranged in the exhaust gas stream, by means
of which drive power can be transferred to a crankshaft of the
internal combustion engine, and the part of the exhaust gas stream
which is conducted through the recirculating line is branched off
from the exhaust gas stream before the exhaust gas turbine in the
direction of flow.
17. A drive train according to claim 11, characterized in that an
exhaust gas turbine is arranged in the exhaust gas stream, by means
of which drive power can be transferred to a crankshaft of the
internal combustion engine, and the part of the exhaust gas stream
which is conducted through the recirculating line is branched off
from the exhaust gas stream before the exhaust gas turbine in the
direction of flow.
18. A drive train according to claim 12, characterized in that an
exhaust gas turbine is arranged in the exhaust gas stream, by means
of which drive power can be transferred to a crankshaft of the
internal combustion engine, and the part of the exhaust gas stream
which is conducted through the recirculating line is branched off
from the exhaust gas stream before the exhaust gas turbine in the
direction of flow.
19. A drive train according to claim 13, characterized in that an
exhaust gas turbine is arranged in the exhaust gas stream, by means
of which drive power can be transferred to a crankshaft of the
internal combustion engine, and the part of the exhaust gas stream
which is conducted through the recirculating line is branched off
from the exhaust gas stream before the exhaust gas turbine in the
direction of flow.
20. A drive train according to claim 14, characterized in that an
exhaust gas turbine is arranged in the exhaust gas stream, by means
of which drive power can be transferred to a crankshaft of the
internal combustion engine, and the part of the exhaust gas stream
which is conducted through the recirculating line is branched off
from the exhaust gas stream before the exhaust gas turbine in the
direction of flow.
21. A drive train according to claim 15, characterized in that an
exhaust gas turbine is arranged in the exhaust gas stream, by means
of which drive power can be transferred to a crankshaft of the
internal combustion engine, and the part of the exhaust gas stream
which is conducted through the recirculating line is branched off
from the exhaust gas stream before the exhaust gas turbine in the
direction of flow.
22. A drive train according to claim 16, characterized in that the
further heat exchanger is arranged in the direction of flow behind
the exhaust gas turbine in the exhaust gas stream.
23. A drive train according to claim 17, characterized in that the
further heat exchanger is arranged in the direction of flow behind
the exhaust gas turbine in the exhaust gas stream.
24. A drive train according to claim 18, characterized in that the
further heat exchanger is arranged in the direction of flow behind
the exhaust gas turbine in the exhaust gas stream.
25. A drive train according to claim 19, characterized in that the
further heat exchanger is arranged in the direction of flow behind
the exhaust gas turbine in the exhaust gas stream.
26. A drive train according to claim 20, characterized in that the
further heat exchanger is arranged in the direction of flow behind
the exhaust gas turbine in the exhaust gas stream.
27. A drive train according to claim 21, characterized in that the
further heat exchanger is arranged in the direction of flow behind
the exhaust gas turbine in the exhaust gas stream.
Description
[0001] The present invention relates to a drive train, especially
for commercial motor vehicles such as trucks, buses, construction
machines, motor coaches of rail vehicles or locomotives, comprising
an internal combustion engine and a steam cycle which is operated
at least partly with heat obtained during the operation of the
internal combustion engine. It can also be used in passenger cars
or other mobile or stationary installations.
[0002] Drive trains are known in which an expansion machine in a
steam cycle is provided as a second drive unit in addition to an
internal combustion engine as the first drive unit. The internal
combustion engine is used for driving the drive train or the
vehicle. The expansion machine can also be used for driving the
vehicle according to a first embodiment, which means feeding drive
power to the drive train for transfer to the drive wheels of the
vehicle, or driving a secondary unit, e.g. a generator, in the
drive train. Conventional heat from the exhaust gas stream of the
internal combustion engine is used for evaporating the working
medium of the steam cycle, with a heat exchanger which guides the
working medium of the steam cycle being arranged in the exhaust gas
stream of the internal combustion engine and is energized by the
exhaust gas in such a way that the heat from the exhaust gas is
transferred to the working medium.
[0003] Heat which would be emitted via the exhaust to the ambient
environment without providing the steam cycle and the utilization
of the waste heat is used conventionally for steam generation. The
generated steam is then guided through the expansion machine in
which it expands under delivery of work. Thereafter, the expanded
steam is guided through a condenser in which it condenses by
supplying heat to the cooling system of the vehicle, in order to be
supplied in the liquid state via a pump to the heat exchanger in
the exhaust gas stream again, which is also known as the steam
generator.
[0004] The provision of a steam cycle conventionally leads to the
consequence that more heat needs to be carried off via the vehicle
cooling system, and the vehicle cooling system needs to be
configured to be more respectively powerful. For example, a cooling
air flow needs to be guided by a fan of the vehicle cooling system
through the condenser.
[0005] Recently, drive trains are equipped with so-called exhaust
gas recirculation (EGR), especially motor vehicles, in order to
adjust the emission values of the internal combustion engine to the
requirements stipulated under the law. Exhaust gas is guided from
the exhaust side of the internal combustion engine to the fresh air
side of the internal combustion engine and mixed with fresh air.
The mixture is then introduced for combustion together with the
fuel into the various cylinders of the internal combustion engine,
compressed and combusted under delivery of work. The share of
exhaust gas acts virtually as an inert gas during the
combustion.
[0006] The share of the exhaust gas stream which is guided in the
exhaust gas recirculation to the fresh air side needs to be cooled
as a result of its high temperature with which it exits from the
internal combustion engine. This occurs conventionally via the
vehicle cooling system, namely with cooling water in a heat
exchanger which is disposed accordingly in the exhaust gas
recirculation. The heat introduced via the exhaust gas
recirculation into the cooling water needs to be passed to the
ambient environment via the vehicle radiator, which consequently
requires a large radiator surface or a strongly increased drive
power for the cooler fan, and optionally a respectively strong
cooling water pump in order to circulate a large cooling water flow
in the cooling water cycle.
[0007] An especially large quantity of heat is introduced into the
vehicle cooling system in drive trains, especially in motor
vehicles, with exhaust gas recirculation and a steam cycle.
[0008] The heat quantity introduced into the vehicle cooling system
can be increased in such way that the drive train is provided with
a so-called supercharged internal combustion engine. It is known
that in such supercharging an exhaust gas turbine is arranged in
the exhaust gas stream, which turbine drives a compressor which
compresses the fresh air for combustion in the internal combustion
engine. During the compression, the fresh air is heated and needs
to be cooled again accordingly before it is introduced into the
internal combustion engine. This conventionally also occurs via the
vehicle radiator, usually via an air/air heat exchanger in contrast
to the cooling of the cooling water in an air/water heat exchanger.
The air/air heat exchanger also needs to be configured in a
respectively powerful way.
[0009] The unexamined German application DE 10 2006 036 122 A1
describes a drive device with an internal combustion engine which
generates an exhaust gas stream. A portion of the exhaust gas is
recirculated by means of exhaust gas recirculation to the fresh air
side of the internal combustion engine. A heat exchanger is
arranged in the exhaust gas recirculation by means of which heat is
transferred from the recirculated exhaust gas to a working medium
cycle with an expansion machine. As a result, a part of the heat of
the exhaust gas guidance in the expansion machine can be utilized.
This utilization of the heat is not optimal however.
[0010] The present invention is based on the object of providing a
drive train, especially for a motor vehicle, e.g. a rail vehicle or
truck, but also a passenger car, which is optimized with respect to
emission values of the internal combustion engine and fuel
consumption and simultaneously reduces the load on the cooling
system by a comparatively low introduction of heat into the
same.
[0011] The object in accordance with the invention is achieved by a
drive train with the features of claim 1. Advantageous and
especially appropriate embodiments of the invention are given in
the dependent claims.
[0012] The drive train in accordance with the invention comprises
an internal combustion engine which generates an exhaust gas
stream. The exhaust gas stream is guided to an exhaust gas line
which is connected accordingly to the internal combustion engine.
It is understood that several exhaust gas lines can be provided in
parallel and/or in series with one another.
[0013] Furthermore, a supply air line system is provided which
comprises at least one supply air line for supplying a supply air
flow for combustion in the internal combustion engine. The supply
air line system is connected accordingly to the internal combustion
engine. The supplied air can concern fresh air or, as illustrated,
a mixture of fresh air and exhaust gas which is mixed with exhaust
gas, for which purpose a fresh air line is provided in the supply
air line system and a recirculating line from the exhaust gas side
to the fresh air side of the internal combustion engine.
[0014] The drive train in accordance with the invention further
comprises a steam cycle which is operated with a working medium
which evaporates in a heat exchanger, expands thereafter by an
expansion machine by delivery of work and is condensed thereafter
in a condenser. The working medium can be water or any other liquid
that is capable of evaporation.
[0015] In accordance with the invention, the heat exchanger, or at
least one heat exchanger by means of which the working medium in
the steam cycle is evaporated at least in part, is provided in the
recirculating line for the exhaust gas, so that heat from the
exhaust gas recirculation can be used for evaporation of the
working medium. Evaporation of the working medium shall be
understood as being any kind of heat transfer into the working
medium, irrespective of whether the working medium is present on
the working medium side in the evaporated state or partly
evaporated state at the end of the heat exchanger in which the heat
transfer occurs, and if not yet it is completely evaporated
especially in a further heat exchanger.
[0016] According to a first embodiment in accordance with the
invention, at least two heat exchangers for evaporating the working
medium of the steam cycle are provided in the exhaust gas
recirculation, which means in the recirculating line as described
initially. The exhaust gas in the recirculating line flows through
the first heat exchanger at first and thereafter through the second
heat exchanger, with the gas emitting heat to the working medium in
each heat exchanger. The working medium of the steam cycle flows
accordingly first through the second heat exchanger in the
recirculating line, thereafter through a further heat exchanger
which is provided in the exhaust gas line which is provided with an
exhaust gas stream designated for further guidance to the ambient
environment, and finally through the first heat exchanger in the
recirculating line. As a result, two heat exchangers are provided
in the recirculating line for evaporation of the working medium of
the steam cycle with mutually different temperature levels. The
interposed further heat exchanger in the exhaust gas line lies with
respect to the temperature level at a level between the temperature
level of the first and second heat exchanger in the recirculating
line, usually as a result of an exhaust gas turbine provided
upstream in the exhaust gas line and/or a diesel particle
filter.
[0017] According to an alternative embodiment in accordance with
the invention, a heat exchanger is provided in the recirculating
line parallel to a further heat exchanger in the exhaust gas line
with respect to the flow of the working medium in the steam cycle,
with a control member provided before and/or after the heat
exchangers in the direction of flow of the working medium being
used to divided the working medium flow optionally in relation to
both heat exchangers. The division can optionally occur in a
variable manner according to an advantageous embodiment in such a
way that the entire working medium flow flows through the heat
exchanger in the recirculating line or through the further heat
exchanger in the exhaust gas line, or that the entire flow is
divided among both heat exchangers at a fixedly predetermined or
variably adjustable ratio. It is also possible to provide a bypass
for the working medium of the steam cycle, which is the heat
exchanger in the recirculating line and the further heat exchanger
in the exhaust gas line, by means of which the working medium can
be guided partly or entirely past the two heat exchangers.
[0018] When a heat exchanger for evaporating the working medium of
the steam cycle in the exhaust gas recirculation is provided in
accordance with the invention, it is then especially possible to
omit the conventional water/gas heat exchanger of the vehicle
cooling system, by means of which the heat was guided into the
cooling water from the share of the exhaust gas stream guided
through the exhaust gas recirculation, or a respectively smaller
dimensioned water/gas heat exchanger of the vehicle cooling system
can be provided in addition, through which cooling water is guided.
Since less heat is introduced into the cooling water as compared
with conventional systems by utilizing heat from the exhaust gas
recirculation for the steam cycle or for generating steam, it is
possible to dimension the vehicle cooling system for a lower
maximum cooling power, in that the radiator by means of which heat
is carried off from the cooling water to the ambient environment is
reduced in size, or the cooling water flow in the vehicle cooling
system is reduced.
[0019] A further heat source which can be used alternatively or
additionally for generating steam, which means for evaporating the
working medium of the steam cycle, is arranged in a drive train
with supercharged internal combustion engine behind a compressor in
the direction of flow of the fresh air, which compressor compresses
the fresh air and is driven especially via an exhaust gas turbine
in the exhaust gas stream of the internal combustion engine. It is
understood that it is also possible to compress a mixture of fresh
air and exhaust gas with such a compressor and/or to drive the
compressor differently than with an exhaust gas turbine, e.g. via
the crankshaft of the internal combustion engine. It is further
possible to provide a single compressor in the supply air line
system, behind which the heat exchanger for steam generation is
positioned in the direction of flow of the fresh air. It is
alternatively possible to provide several compressors behind one
another or a multi-stage compressor in the supply air line system
and to then arrange a respective heat exchanger for steam
generation between two compressors or between two compressor stages
or behind several or all compressors or compressor stages. As a
result, the heat produced during the compression of the supplied
air can be used in a purposeful manner for operating the expansion
machine and thus for generating drive power.
[0020] The invention will be explained below in an exemplary manner
by reference to embodiments, wherein:
[0021] FIG. 1 shows a drive train in accordance with the invention
with a plurality of heat exchangers used for steam generation in
the exhaust gas recirculation and a further heat exchanger in the
exhaust gas stream of the internal combustion engine;
[0022] FIG. 2 shows an embodiment according to FIG. 1, but with an
additionally integrated turbocompound system;
[0023] FIG. 3 shows an alternative arrangement of the invention
with a division of the flow of the working medium of the steam
cycle to parallel switched heat exchangers in the exhaust gas
recirculation and the exhaust gas line;
[0024] FIG. 4 shows a modification of FIG. 3;
[0025] FIG. 1 shows an internal combustion engine 1 with an exhaust
gas line 2 and a supply air line system 3. The supply air line
system 3 comprises a fresh air line 3.1 in which a compressor 7 is
arranged. The compressed fresh air is mixed with a proportion of
the exhaust gas which is recirculated via a recirculating line 3.2
to the fresh air side of the internal combustion engine 1 and
supplied to the internal combustion engine 1 for combustion. In the
present case, the quantity of the recirculated share which flows
through the recirculating line 3.2 can be adjusted via a control
valve 12.
[0026] The compressor 7 for compressing fresh air is driven via an
exhaust gas turbine 10 which is arranged in the exhaust gas stream
of the internal combustion engine 1. A particle filter 13 for
filtering particles, especially exhaust particulates, from the
exhaust gas stream is arranged in the direction of flow behind the
exhaust gas turbine 10.
[0027] A steam cycle 4 is provided in accordance with the invention
in which steam is generated which expands in the expansion machine
5 and is condensed in a condenser 7. In the present case, the
expansion machine 5, e.g. in the form of a steam turbine or a
piston engine, is used for introducing drive power into the
crankshaft 11 of the internal combustion engine. It would
alternatively also be possible to drive an auxiliary unit of the
drive train with the expansion machine 5, or to introduce drive
power to the drive wheels via another drive connection when used in
a motor vehicle.
[0028] In the illustrated embodiment, the condensed steam is guided
into a collecting vessel 14 and thereafter through a pump 15 in
order to circulate the working medium of the steam cycle 4 in the
steam cycle or to bring the working medium to the required
pressure.
[0029] In the embodiment as shown in FIG. 1, three heat exchangers
6.1, 6.2 and 16 are arranged in the recirculating line 3.2 of the
supply air line system 3, which heat exchangers are flowed through
successively in the direction of flow of the recirculated exhaust
gases in the mentioned sequence before the exhaust gas is mixed
with fresh air from the fresh air line 3.1. Accordingly, the first
heat exchanger 6.1 is provided with the recirculated share of the
exhaust gas stream at a higher temperature than the second heat
exchanger 6.2, the third heat exchanger 16 will only be provided or
a cooling of the recirculated exhaust gas will only occur when this
is necessary as a result of a too high outlet temperature of the
recirculated exhaust gas stream from the second heat exchanger
6.2.
[0030] The working medium of the steam cycle 4 is guided at first
through the second heat exchanger 6.2 in the recirculating line 3.2
before it enters the first heat exchanger 6.1 in the recirculating
line 3.2. Furthermore, a further heat exchanger 9 is provided in
the steam cycle between the second heat exchanger 6.2 and the first
heat exchanger 6.1 in order to heat or evaporate the working medium
of the steam cycle 4. Said further heat exchanger 9 is arranged in
the exhaust gas stream of the proportion of exhaust gas which is
passed to the ambient environment after flowing through the further
heat exchanger 9. In this case, the further heat exchanger 9 is
provided in the direction of flow of the exhaust gas behind the
particle filter 13.
[0031] The illustrated number of heat exchangers and the presently
described specific sequence of through-flow of the same with
exhaust gas and working medium of the steam cycle 4 optimizes the
introduction of heat into the working medium by means of the
temperature level at which the heat transfer occurs. It is possible
to deviate from the illustrated embodiment, e.g. the further heat
exchanger 9 can be provided at a different position in the exhaust
gas stream. Alternatively or in addition, three or more heat
exchangers which are flowed through by working medium could be
provided in the recirculating line 3.2. Finally, as it is
illustrated, the heat exchanger 16 which is flowed through by
cooling water could be saved or be replaced for example by an
exhaust gas/cooling air heat exchanger or other heat exchanger.
[0032] It is naturally also possible to save the particle filter 13
or to position the same at another position in the exhaust gas
stream. Alternatively or additionally, the use of an SCR system for
selective catalytic reduction of nitrogen oxides in the exhaust gas
is possible, e.g. at the position of the particle filter 13 or
behind the same, or naturally at another position. It is also
possible to provide an SCRT.RTM. system (selective catalytic
reduction trap), or a combination of CRT.RTM. and SCR system. A
CRT.RTM. combines the effect of a particle filter with that of an
oxidation catalytic converter.
[0033] In the embodiment as shown in FIG. 1, the fresh air (charge
air) which is compressed in the compressor 7 in the fresh air line
3.1 is cooled in an air-cooled heat exchanger 17 of the cooling
system in an application in a motor vehicle, especially a motor
vehicle cooling system, before it is mixed with the recirculated
exhaust gas. A respective cooling could be provided in addition or
alternatively even after the mixture. Especially advantageously, a
respective heat exchanger or several heat exchangers for cooling
this compressed fresh air, before or after its mixture with the
recirculated exhaust gas, could be "cooled" by the working medium
of the steam cycle 4, so that this occurring heat could also be
used for steam generation.
[0034] FIG. 1 shows a cooling water cycle with reference numeral 18
in which a radiator 19 (water/air radiator) is arranged, as is
known. Reference numeral 20 indicates the respective cooling air
which is guided through the radiator 19 or the heat exchanger 17.
As is shown, the cooling water in the cooling cycle, especially the
vehicle cooling cycle, is used for cooling the internal combustion
engine 1 and, in the specially illustrated embodiment, for
additionally cooling down the recirculated exhaust gas stream, when
the maximum possible heat was extracted from the same by means of
the steam cycle 4.
[0035] In the illustrated embodiment, the condenser 7 is also
supplied with the cooling air 20.
[0036] In the embodiment as shown in FIG. 2, in connection of which
the description of FIG. 1 also applies accordingly, the drive power
of the exhaust gas turbine 10 is additionally transferred to the
crankshaft 11 of the internal combustion engine 1, which occurs
here via a respective transmission. When the direction of power is
reversed, the compressor 7 can thus be driven for compressing the
fresh air by means of the internal combustion engine 1, which
advantageously always occurs when an only comparatively low exhaust
gas stream is available. The so-called turbo lag can thus be
reduced or avoided.
[0037] As is indicated with the broken line, the compressor 7 can
also be driven via an exhaust gas turbine 8 (turbo-supercharger
turbine) which is provided in addition to the exhaust gas turbine
10 in the exhaust gas stream or the exhaust line 2 and is usually
provided upstream with respect to the direction of the exhaust gas
stream of the exhaust gas turbine 10, and the exhaust gas turbine
10 (which is then designated as an exhaust gas power turbine) is
used exclusively for introducing drive power into the crankshaft 11
of the internal combustion engine 1 in order to form a
turbocompound system.
[0038] FIG. 3 shows an embodiment in which the respective
components are marked with respective reference numerals. FIG. 3
does not show all components that were explained in detail in FIGS.
1 and 2. The internal combustion engine 1 is shown in which
crankshaft 11 is in a drive connection with the expansion machine 5
via a hydrodynamic coupling which can be arranged to be
controllable or non-controllable as in the previously illustrated
embodiments, or can be switched into such a drive connection.
Instead of a hydrodynamic coupling it is also possible to provide
any other non-hydrodynamic coupling, especially one that is
controllable. The internal combustion engine 1 is cooled by means
of a cooling medium (usually cooling water) which is circulated in
a cooling cycle (see the indicated radiator 19). In this respect,
reference can be made to the description in FIG. 1. A recirculating
line 3.2 for recirculated exhaust gas is provided here again, and
an exhaust gas line 2 with an exhaust gas turbine 10 and diesel
particulate filter 13. It is understood that the exhaust gas
turbine 10 and/or the diesel particulate filter 13 could be omitted
if so desired. The statements made above apply to the further
exhaust gas treatment.
[0039] The working medium of the steam cycle flows from the pump 15
to a control member 21. It would principally be possible that the
working medium flows through one or several further heat exchangers
(not shown) before it enters the control member 21, e.g. a heat
exchanger in a vehicle cooling cycle and/or a heat exchanger for
intermediate cooling of compressed fresh air (charge air cooler).
The control member 21 causes a division of the working medium flow
of the steam cycle in the direction towards a heat exchanger 6 in
the recirculating line 3.2 in the direction to a further heat
exchanger 9 in the exhaust gas line 2. The working medium flow of
the steam cycle is combined again after these two heat exchangers
6, 9 and supplied to the expansion machine 5. It is obvious that
here further heat exchangers could be provided.
[0040] The control member 21 is usually triggered by means of a
control apparatus in such a way that the division of the working
medium flow in the steam cycle to the two heat exchangers 6 and 9
occurs depending on one or several predetermined input quantities
which can be detected or calculated. Such an input quantity can be
a temperature at a certain point in the exhaust gas stream, the
drive train or the steam cycle for example. The speed, the torque
and/or the power output of the internal combustion engine 1 could
be used as an input quantity. Further input quantities are
possible.
[0041] FIG. 4 shows a modification of FIG. 3, in which the division
of the working medium flow in the steam cycle to the two parallel
heat exchangers 6 and 9 is not achieved by means of a control
member dividing the working medium flow but by two pumps 15.1 and
15.2 which are switched in parallel with respect to one another. As
a result, pump 15.1 conveys the working medium flow in the steam
cycle through the heat exchanger 6 in the recirculating line 3.2,
and pump 15.2 conveys the working medium flow of the steam cycle
through the further heat exchanger 9 in the exhaust gas line 2.
When the pumps 15.1 and 15.2 are arranged to be controllable or
adjustable with respect to their conveying performance and are
arranged especially to be speed-controlled or speed-adjusted, the
working medium volume flow or the working medium mass flow in each
of the parallel branches of the steam cycle, which is in the branch
with heat exchanger 6 and in the branch with heat exchanger 9, can
be controlled or adjusted individually. The pumps 15.1 and 15.2 can
be arranged like pump 15 in the preceding embodiments as a
displacement machine for example. Other arrangements are also
possible, e.g. as a turbo machine. The two pumps 15.1 and 15.2
which are thus especially individually speed-controlled or
speed-adjusted convey for example from a common collecting vessel
for working medium, e.g. as was shown with reference to FIG. 1.
[0042] The described invention is preferably used in a motor
vehicle. An application in a stationary drive train, e.g. in a
block heating station, is possible for example. In the case of an
application in a vehicle, the internal combustion engine
(optionally in addition to the expansion machine 5 used for driving
the car) may be the only drive unit for driving the vehicle, or
further drive units for driving the vehicle can be provided, e.g.
an electric motor.
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