U.S. patent application number 12/160934 was filed with the patent office on 2010-07-29 for device for cooling waste gas.
This patent application is currently assigned to BEHR GMBH & CO.KG. Invention is credited to Karsten Emrich, Thomas Mitchell, Timm Roschmann.
Application Number | 20100186397 12/160934 |
Document ID | / |
Family ID | 38268792 |
Filed Date | 2010-07-29 |
United States Patent
Application |
20100186397 |
Kind Code |
A1 |
Emrich; Karsten ; et
al. |
July 29, 2010 |
DEVICE FOR COOLING WASTE GAS
Abstract
The invention relates to a device for cooling waste gas,
comprising an inlet area (1) for guiding a flow of waste gas, an
outlet area (2) for discharging the optionally cooled waste gas,
and a longitudinal housing (1) for receiving exchanging means (13)
for heat exchange. The flow of waste gas flows through the
exchanging means (13) on the way from the inlet area to the outlet
area. The inlet area (2) and the outlet area (3) are arranged
respectively on end areas of the housing (1) which are opposite in
relation to the longitudinal direction. The flow of waste gas flows
through the exchanging means (13) on a first flow path (16) and
also on a second flow path (17) which is counter thereto.
Inventors: |
Emrich; Karsten; (Stuttgart,
DE) ; Roschmann; Timm; (Stuttgart, DE) ;
Mitchell; Thomas; (Sindelfingen, DE) |
Correspondence
Address: |
FOLEY AND LARDNER LLP;SUITE 500
3000 K STREET NW
WASHINGTON
DC
20007
US
|
Assignee: |
BEHR GMBH & CO.KG
Stuttgart
DE
|
Family ID: |
38268792 |
Appl. No.: |
12/160934 |
Filed: |
January 11, 2007 |
PCT Filed: |
January 11, 2007 |
PCT NO: |
PCT/EP2007/000213 |
371 Date: |
October 20, 2008 |
Current U.S.
Class: |
60/320 ;
165/164 |
Current CPC
Class: |
Y02T 10/16 20130101;
Y02T 10/12 20130101; F02M 26/32 20160201; F02M 26/11 20160201; F02M
26/26 20160201 |
Class at
Publication: |
60/320 ;
165/164 |
International
Class: |
F01N 3/02 20060101
F01N003/02; F28D 7/00 20060101 F28D007/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 19, 2006 |
DE |
10 2006 002 856.2 |
Nov 15, 2006 |
DE |
10 2006 054 222.3 |
Claims
1. A device for cooling waste gas, comprising an inlet region for
supplying a flow of waste gas, an outlet region for discharging the
optionally cooled waste gas, and a longitudinal housing for
receiving exchanger means for exchanging heat, the flow of waste
gas flowing through the exchanger means on a route from the inlet
region to the outlet region, the inlet region and the outlet region
each being arranged at end regions of the housing which are
opposite in relation to the longitudinal direction, wherein the
flow of waste gas flows through the exchanger means on a first flow
path and also on a second flow path which is counter thereto.
2. The device as claimed in claim 1, wherein the device is a waste
gas cooler for an internal combustion engine of a motor
vehicle.
3. The device as claimed in claim 1, wherein the exchanger means
comprise a plurality of tubes for guiding waste gas which extend in
the longitudinal direction and are arranged in the housing.
4. The device as claimed in claim 3, wherein the housing has
connections through which a liquid coolant can flow.
5. The device as claimed in claim 3, wherein the tubes are each
secured in their end regions in common head pieces.
6. The device as claimed in claim 3, wherein a first group of the
tubes is associated with the first flow path and a second group of
tubes is associated with the second flow path.
7. The device as claimed in claim 3, wherein a waste gas channel is
provided and is arranged in the longitudinal direction and
substantially parallel to the tubes.
8. The device as claimed in claim 7, wherein the waste gas channel
is connected directly to the inlet region.
9. The device as claimed in claim 8, wherein the device comprises a
deflection means for deflecting the flow of waste gas from the
waste gas channel into the first flow path.
10. The device as claimed in claim 9, wherein the device comprises
a further deflection means for deflecting the flow of waste gas
from the first flow path into the second flow path.
11. The device as claimed in claim 10, wherein the further
deflection means is configured as a curved sheet metal part.
12. The device as claimed in claim 1, wherein the device comprises
an adjustment device for selectively guiding the flow of waste
gas.
13. The device as claimed in claim 12, wherein the adjustment
device in a first end position leads the flow of waste gas into the
first flow path and in a second end position leads it into an
outlet opening.
14. The device as claimed in claim 13, wherein the flow of waste
gas in the second end position is not guided by the exchanger
means, so that cooling of the flow of waste gas is substantially
avoided in the second end position.
15. The device as claimed in claim 12, wherein the adjustment
device comprises a flap which can rotate about an axis.
16. The device as claimed in claim 15, wherein a maximum angle of
rotation of the flap is not more than approximately 40 degrees, in
particular not more than approximately 30 degrees.
17. The device as claimed in claim 12, wherein the adjustment
device can be driven via an actuator.
18. The device as claimed in claim 1, wherein the adjustment device
comprises a spring, the spring allowing a restoring force to be
exerted in the direction of an end position of the adjustment
device.
19. The device as claimed in claim 18, wherein the spring is
configured as a coil spring.
20. The device as claimed in claim 19, wherein a rotatable shaft of
the adjustment device is arranged within the coil spring.
21. The device as claimed in claim 18, wherein the spring has a
coating, in particular made of a plastics material.
22. The device as claimed in claim 21, wherein the coating
comprises a polymer based on a fluorinated hydrocarbon, in
particular polytetrafluoroethylene.
23. The device as claimed in claim 18, wherein the spring is
arranged within a sleeve covering the spring.
24. The device as claimed in claim 1, wherein the ratio of a length
of the housing in the longitudinal direction to a largest diameter
of the housing is less than approximately 3.5, in particular less
than approximately 3.
Description
[0001] The invention relates to a device for cooling waste gas
according to the preamble of claim 1.
[0002] Heat exchangers which serve to cool waste gases of an
internal combustion engine are known in particular from the
construction of motor vehicles. Known among these heat exchangers
are designs which are referred to on the one hand as "I-flow"
arrangements and on the other hand as "U-flow" arrangements. The
former case relates to heat exchangers in which the inlet and
outlet connections for the waste gas are arranged on opposite sides
of an elongate housing, the waste gas flowing through the heat
exchanger region only once in a longitudinal direction. In the
latter arrangement, the waste gas flows through the heat exchanger
in a back and forth direction, i.e. in the shape of a U, so that
frequently the inlet region and the outlet region are arranged on
the same side of an exchanger housing.
[0003] The object of the invention is to disclose a heat exchanger
in which, with good flexibility with regard to the installation
position of the heat exchanger, a good cooling power is achieved in
a given overall space.
[0004] According to the invention, for a heat exchanger mentioned
at the outset, this object is achieved by the characterizing
features of claim 1. This ensures, in a given overall space, a
longer flow path of the flow of waste gas along the exchanger
means, thus allowing a high cooling power to be achieved.
[0005] In an advantageous configuration, the device is a waste gas
cooler for an internal combustion engine of a motor vehicle. The
device according to the invention can be used advantageously in
particular in combination with the often narrowly defined overall
spaces in the case of motor vehicle engines. This applies above all
at defined positions of the connections of the waste gas lines.
[0006] In a preferred exemplary embodiment, the exchanger means
comprise a plurality of tubes for guiding waste gas which extend in
the longitudinal direction and are arranged in the housing. Also
advantageously, the housing has connections through which a liquid
coolant can flow. Overall, this forms an effective, overall
space-optimized waste gas heat exchanger with liquid cooling in a
tube bundle design. Alternatively thereto, the device according to
the invention can however also be an air-cooled waste gas
cooler.
[0007] Also advantageously, the tubes can each be secured in their
end regions in common head pieces. This allows a waste gas cooler
to be produced in a simple manner.
[0008] Preferably, a first group of the tubes is associated with
the first flow path and a second group of the tubes is associated
with the second flow path, thus providing an extended total flow
route of the flow of waste gas in a simple manner.
[0009] In a particularly advantageous development, a waste gas
channel is provided and is arranged in the longitudinal direction
and substantially parallel to the tubes. The waste gas channel can
in this case be a single channel having a suitable cross section
for low-resistance guidance of the total flow of waste gas or else
a divided channel or a bundle consisting of separate tubes.
Advantageously, the waste gas channel is connected directly to the
inlet region. Particularly preferably, the device comprises in this
case a first deflection means for deflecting the flow of waste gas
from the waste gas channel into the first flow path. Also
advantageously, the device comprises a second deflection means for
deflecting the flow of waste gas from the first flow path into the
second flow path. Overall, this forms in a simple manner a compact
heat exchanger in which the flow of waste gas is guided via two
deflections firstly from the inlet region in the direction of the
outlet region, then in the opposite direction and then again in the
direction of the outlet region. The exchanger means for cooling the
flow of waste gas are in this case arranged in the region of the
first and the second flow path, wherein the waste gas channel does
not necessarily serve to exchange heat. For a simple embodiment,
the second deflection means can in particular preferably be
configured as a curved sheet metal part.
[0010] It is generally preferable for the device to comprise an
adjustment device for selectively guiding the flow of waste gas.
This ensures increased flexibility during waste gas guidance.
Particularly preferably, the adjustment device leads the flow of
waste gas in a first end position into the first flow path and in a
second end position into the outlet region. As a result, the
adjustment device can be used to select whether or not the flow of
waste gas flows through the cooling exchanger region. In the latter
case, one waste gas channel can in particular have the function of
a bypass line, wherein it has in the first end position of the
adjustment device the function of a feed line to the exchanger
means. For this purpose, provision is preferably made for the flow
of waste gas not to be guided in the second end position through
the exchanger means, thus substantially preventing cooling of the
flow of waste gas in the second end position.
[0011] In a particularly simple and preferred embodiment, the
adjustment device comprises a flap which can rotate about an axis.
In order to achieve a particularly small design, provision is
preferably made for a maximum angle of rotation of the flap to be
not more than 40 degrees, in particular not more than approximately
30 degrees. This relatively small angle of adjustment allows a
drive unit for the flap to be designed cost-effectively and simply.
It is generally preferable for the adjustment device to be able to
be driven via an actuator.
[0012] In a further preferred detailed configuration, the
adjustment device comprises a spring, the spring allowing a
restoring force to be exerted in the direction of an end position
of the adjustment device. Advantageously, the spring is in this
case configured as a coil spring, and a rotatable shaft of the
adjustment device is arranged within the coil spring. In this way,
a high restoring force of the adjustment device, for example a
rotatable flap, can be provided compactly and effectively. This may
be desirable especially when an actuator of the adjustment device
applies its adjusting force predominantly in just one
direction.
[0013] Particularly advantageously, the spring has a coating, in
particular made of a plastics material. This prevents restriction
of the spring caused by metal spraying around or welding beads such
as are formed for example during the manufacture of the device.
[0014] Generally, the adjustment device is initially inserted
during manufacture between separate housing parts, after which the
housing parts are permanently welded to one another. During this
welding process, the spring is often in an exposed position and can
become blocked or damaged by welding beads. The coating of the
spring can prevent this. Expediently, the coating can in this case
be subjected to as high temperatures as possible, for which purpose
the coating preferably comprises a polymer based on a fluorinated
hydrocarbon, in particular polytetrafluoroethylene (PTFE). Such
polymers having good surface slip and high heat resistance are
known for example under the commercial name Teflon.RTM..
[0015] If it is sufficiently heat-resistant, the coating can be
preserved even after manufacture during operation of the waste gas
coolers. This allows the frictional resistance of the spring wire,
which is for example wound helically with mutually touching
windings, to be reduced and any noise formation is avoided. In
addition, the coating provides good protection of the spring from
corrosion. In principle, the coating can however also be broken
down by the operating temperatures or for example be removed by
evaporation.
[0016] An alternative or additional embodiment provides a sleeve
which at least partly covers the spring and forms a protective
cover from metal drops which spray around during the production
process.
[0017] A spring, protected in this way by coating and/or a sleeve,
of an adjustment device can in principle advantageously be combined
with any design of a waste gas cooler and is not limited to the
particular design of the present device.
[0018] In a preferred combination with the aforementioned features
of the device, the ratio of a length of the housing in its
longitudinal direction to a largest diameter of the housing is less
than 3.5, in particular less than approximately 3. This provides a
particularly compact design, so that the device can be used
universally.
[0019] Further advantages and features of a device according to the
invention will emerge from the exemplary embodiment described
hereinafter and also from the dependent claims.
[0020] A preferred exemplary embodiment of a device according to
the invention will be described hereinafter and commented on with
reference to the appended drawings, in which:
[0021] FIG. 1 is a three-dimensional view of a device according to
the invention, looking onto the outlet region;
[0022] FIG. 2 shows the device from FIG. 1, looking onto the inlet
region;
[0023] FIG. 3 is a three-dimensional sectional view of the device
from FIG. 1, looking onto the outlet region;
[0024] FIG. 4 is a three-dimensional sectional view of the device
from FIG. 3, looking onto the inlet region; and
[0025] FIG. 5 is a schematic sectional view of the device from FIG.
1 to FIG. 4.
[0026] The device for cooling a flow of waste gas according to the
preferred exemplary embodiment is used in the engine compartment of
a car. It has a housing 1 which is configured as an elongate body
having a substantially rectangular cross section. In its
longitudinal direction, there are arranged on one end side of the
housing an inlet region 2 and on the opposing end side an outlet
region 3. These end side regions 2, 3, which are also referred to
as diffusers, each consist of compression-molded parts which are
welded to the housing 1. In the regions of the connection, the
housing 1 has slightly projecting thickenings 1c.
[0027] A rectangular flange 2a, by means of which a waste gas line
originating from the internal combustion engine of the car can be
connected to the device, is attached to the inlet region by
welding. The outlet-side continuation of the waste gas line can be
produced via a round flange 3a welded onto the outlet region 3.
[0028] The housing 1 comprises two connections 1a, 1b via which a
liquid coolant can flow through the heat exchanger housing 1 in a
manner known per se.
[0029] An actuator 4, which is configured as a pressure box, is
secured to the housing 1 via a holding metal sheet 5. A lifting rod
6 of the actuator 4 drives via a rotary lever 7 a rotary shaft 9
which is loaded with a restoring force via a spring 8. The rotary
shaft 9 passes through the wall of the outlet region 3 and is
rigidly connected to an adjustment flap 10 in the interior of the
outlet region 3, so that rotation of the shaft 9 allows the
adjustment flap 10 to be adjusted. All of the drawings FIG. 1 to
FIG. 5 show the above-described drive mechanism and the adjustment
flap 10 both in a first end position and in a second end position.
The flap 10 rests in the first end position with its edge against
the wall of the outlet region 3 and in the second end position
against a small guiding metal sheet 19. Overall, the actuator 4,
the rotary shaft 9 and the flap 10 form an adjustment device of the
heat exchanger.
[0030] The spring 8 is configured as a coil spring made of a wound
spring wire, the rotary shaft 9 passing through the windings. The
ends of the spring winding are supported at one end against the
housing and at the other end against the rotary lever 7, so that
the spring applies force to the rotary shaft 9 in the direction of
an end position of the adjustment flap.
[0031] The spring wire is coated over its entire length with PTFE
(polytetrafluoroethylene, Teflon.RTM.). During manufacture of the
waste gas cooler, the rotary shaft 9 is first pushed and secured
through the spring 8 and wall of the outlet region, the adjustment
flap 10 being welded to the rotary shaft. Subsequently, still
further welding operations are carried out, for example the welding
of the outlet region 3 onto the further housing 1. During these
welding processes of the production process, liquid metal spraying
around causes welding beads to accumulate in the environment of the
immediate welding process. The PTFE coating prevents the welding
beads from clinging to the spring 8. In addition, the PTFE has such
high heat resistance that it is not broken down or even does not
catch fire even in normal operation of the waste gas cooler.
[0032] The interior of the device is constructed as follows: The
inlet-side flange 2a opens into a cavity 2b in the inlet region 2.
The inlet region 2 is divided into the aforementioned cavity 2b and
a further cavity 2c via a first deflection means 11. The deflection
means 11 is configured as a curved metal sheet which, in order to
simplify production, is welded on during assembly of the
device.
[0033] A waste gas channel 12, which passes through the housing 1
in its longitudinal direction, adjoins the cavity 2b. The waste gas
channel 12 opens into a first portion 3b of the outlet region 3.
Although the waste gas channel 12 does in principle impart a
certain cooling to the flow of waste gas, especially as its walls
are thermally conductive, it is not configured so as to exchange
heat with the liquid coolant, so that the flow of waste gas is
cooled in the sense of the invention not substantially in the waste
gas channel 12.
[0034] A plurality of tubes 13, which in the present example are
configured as flat tubes having a rectangular cross section, are
provided parallel to the waste gas channel 12. The plurality of
tubes 13 and the waste gas channel 12, which is configured as a
single tube having a much larger cross section, are jointly
received between a respective end-side head piece 14, 15. These
head pieces 14, 15 are strong holding metal sheets with
corresponding punched-out portions for receiving the ends of the
tubes. The head pieces 14, 15 are all tightly welded to the ends of
the tubes and to the housing 1, thus forming between the head
pieces and an outer wall of the housing 1 a cavity which remains
between the individual tubes and through which the coolant can
flow. Flowing around the waste gas channel 12 can in this case be
prevented by further measures, depending on the desired cooling
power of the waste gas channel 12. The coolant flows during
operation around the tubes 13 which thus constitute exchanger means
for exchanging heat for the waste gas.
[0035] In the case of the present invention, the plurality of tubes
13 are divided into a first group and a second group of tubes 13.
In this case, the first group of tubes is associated with a first
flow path 16 and the second group of tubes with a second flow path
17 (see the arrows indicating the flow paths in FIG. 5).
[0036] The bundle of tubes 13 is divided into two flow paths 16, 17
by a first deflection means 18 arranged in the outlet region 3. The
deflection means 18 is arranged as a flow metal sheet between the
head piece 15 and the shaft 9 of the adjustment flap 10. The
deflection means 18 separates the first space 3b of the outlet
region 3 from a second space 3c. The first space 3b is located at
the entry of the first flow path 16 and the second space 3c is
located at the exit of the second flow path 17.
[0037] The function of the device according to the invention may be
seen particularly clearly from the view according to FIG. 5:
[0038] The flap 10 can be moved between two end positions, both of
which are indicated for the sake of clarity, through approximately
25 degrees with respect to an angle of rotation of the shaft 9. The
left-hand stop, as shown in FIG. 5, of the flap 10 corresponds to a
first end position. In any case, the flow of waste gas is first
led, after entering through the flange 2a and flowing through the
space 2b, through the waste gas channel 12 in which, however, it
experiences no or only slight cooling. Once the flow of waste gas
has entered the space 3b, there are various possibilities,
depending on the position of the flap 10, for further guidance of
the flow of waste gas. In the case of the first end position
(left-hand stop), the flow of waste gas is led from the space 3b
into the first group of tubes or the first flow path 16. On this
first flow path, the flow of waste gas passes through the housing 1
in the longitudinal direction, in the direction counter to the
waste gas channel 12 (see the arrows in FIG. 5). At the end of the
first flow path, the flow of waste gas enters the space 2c of the
first inlet region, where it is deflected through approximately 180
degrees. Afterwards, it enters the other bundle of tubes or the
second flow path 17 on which it passes through the longitudinal
direction of the housing 1, again in the opposite direction. After
leaving the flow path 17, the flow of waste gas enters the space 3c
and afterwards the outlet flange 10. In the case of this first end
position of the flap 10, the flow of waste gas passes through the
heat exchanger means 13 thus on a U-shaped route, so that the total
flow length along the surfaces of the cooled tubes 13 corresponds
to approximately twice the length of the housing 1.
[0039] In the case of the second end position, which corresponds to
the right-hand stop of the flap 10 in FIG. 5, the flow of waste gas
is supplied, after flowing through the space 3b, directly to the
outlet flange 10 without the flow of waste gas flowing through the
exchanger means or cooled tubes 13. In this mode of operation, the
waste gas channel 12 has a function similar to bypass channels
known per se of heat exchangers which are flowed through only in
one direction. In the case of the first end position, in which the
flow of waste gas is cooled, the waste gas channel 12 does not have
the function of a bypass channel, but rather the function of a feed
line to the exchanger means 13.
[0040] This arrangement provides a heat exchanger which has a very
compact design and at the same time has at one of its ends an inlet
region and at its other, opposing end an outlet region. As may be
seen from the true-to-scale drawings, the length of the housing 1,
including the inlet and outlet regions 2, 3, is in this case less
than three times a maximum housing diameter in a direction
perpendicular to the longitudinal direction. The dimensions and
overhangs of the flanges 2a, 3a were not taken into account in this
calculation. The flanges can also easily be made more compact, for
example by directly welding the feeding and discharging waste gas
tubes to the heat exchanger device. In particular, the relatively
small angle of adjustment of the flap 10 between the two end
positions contributes to the compact design of the device.
* * * * *