U.S. patent application number 12/313165 was filed with the patent office on 2009-05-28 for heat exchanger.
This patent application is currently assigned to DENSO CORPORATION. Invention is credited to Masaki Harada, Sumio Susa, Haruhiko Watanabe.
Application Number | 20090133860 12/313165 |
Document ID | / |
Family ID | 40668730 |
Filed Date | 2009-05-28 |
United States Patent
Application |
20090133860 |
Kind Code |
A1 |
Harada; Masaki ; et
al. |
May 28, 2009 |
Heat exchanger
Abstract
In a heat exchanger, a tube is adapted to exchange heat between
a first fluid flowing therein and a second fluid flowing through
outside of the tube, and an inner fin is disposed in the tube to
divide a flow passage in the tube into a plurality of flow paths.
The inner fin includes a plurality of fin portions with different
specifications, and the fin portions are arranged in series with
respect to a flow direction of the first fluid. Furthermore, the
fin portion with the smallest flowing resistance of the first fluid
among the plurality of fin portions is arranged on an upstream side
of the flow direction of the first fluid with respect to at least
an another fin portion. Accordingly, heat exchange performance in
the entire heat exchanger can be effectively improved.
Inventors: |
Harada; Masaki; (Anjo-city,
JP) ; Susa; Sumio; (Anjo-city, JP) ; Watanabe;
Haruhiko; (Obu-city, JP) |
Correspondence
Address: |
HARNESS, DICKEY & PIERCE, P.L.C.
P.O. BOX 828
BLOOMFIELD HILLS
MI
48303
US
|
Assignee: |
DENSO CORPORATION
Kariya-city
JP
|
Family ID: |
40668730 |
Appl. No.: |
12/313165 |
Filed: |
November 18, 2008 |
Current U.S.
Class: |
165/151 |
Current CPC
Class: |
F28D 1/05366 20130101;
F28F 1/128 20130101; F28F 1/40 20130101; F28D 2021/0082
20130101 |
Class at
Publication: |
165/151 |
International
Class: |
F28D 7/00 20060101
F28D007/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 22, 2007 |
JP |
2007-303289 |
Claims
1. A heat exchanger comprising: a tube having therein a flow
passage through which a first fluid flows, the tube being adapted
to exchange heat between the first fluid and a second fluid flowing
through an outer periphery of the tube; and an inner fin provided
in the tube to promote the heat exchange between the first fluid
and the second fluid, the inner fin being configured to divide the
flow passage in the tube into a plurality of flow paths, wherein
the inner fin includes a plurality of fin portions with different
specifications, the fin portions are arranged in series with
respect to a flow direction of the first fluid, and the fin portion
with the smallest flowing resistance of the first fluid among the
plurality of fin portions is arranged on an upstream side of the
flow direction of the first fluid with respect to at least an
another fin portion.
2. The heat exchanger according to claim 1, wherein the fin portion
with the largest flowing resistance of the first fluid among the
plurality of fin portions is arranged on a downstream side of the
flow direction of the first fluid with respect to the other fin
portion.
3. The heat exchanger according to claim 1, wherein the fin
portions are arranged symmetrically with respect to a center line
of the inner fin in the flow direction of the first fluid.
4. The heat exchanger according to claim 1, wherein the fin
portions are constructed of at least first and second different
kinds of fin portions.
5. The heat exchanger according to claim 1, wherein the plurality
of fin portions include a straight fin portion having a plurality
of wall surfaces extending linearly in the flow direction of the
first fluid, the wall surfaces being configured to divide the flow
passage of the tube into the plurality of flow paths, and a louver
fin portion including a plurality of flat portions substantially in
parallel to the flow direction of the first fluid, and a plurality
of louvers provided at the flat portions along the flow direction
of the first fluid, the louvers being formed by cutting and raising
a part of the flat portion, wherein the straight fin portion is
arranged on an upstream side of the flow direction of the first
fluid, with respect to the louver fin portion.
6. The heat exchanger according to claim 1, wherein the plurality
of fin portions include a straight fin portion having a plurality
of wall surfaces extending linearly in the flow direction of the
first fluid, the wall surfaces being configured to divide the flow
passage of the tube into the plurality of flow paths, and an offset
fin portion including wall portions arranged in a zigzag shape
along the flow direction of the first fluid, the wall portions
being configured to divide the flow passage of the tube into the
plurality of flow paths, wherein the straight fin portion is
arranged on an upstream side of the flow direction of the first
fluid, with respect to the offset fin portion.
7. The heat exchanger according to claim 1, wherein the inner fin
is a louver fin including a plurality of flat portions
substantially in parallel to the flow direction of the first fluid,
and a plurality of louvers provided at the flat portions along the
flow direction of the first fluid, the louver being formed by
cutting and raising a part of the flat portion, the fin portions
are configured to have different louver pitches in the louvers, and
the fin portion with the largest louver pitch among the plurality
of fin portions is arranged on an upstream side of the flow
direction of the first fluid, with respect to at least an another
fin portion.
8. The heat exchanger according to claim 1, wherein the fin
portions have different fin pitches, and the fin portion with the
largest fin pitch among the fin portions is arranged on an upstream
side of the flow direction of the first fluid, with respect to at
least an another fin portion.
9. The heat exchanger according to claim 1, wherein the fin
portions are continuously arranged in the flow direction of the
first fluid such that flow resistances of the first fluid in the
fin portions are increased as toward downstream in the flow
direction of the first fluid.
10. The heat exchanger according to claim 1, wherein the first
fluid flowing in the tube generally has a temperature higher than
that of the second fluid.
11. The heat exchanger according to claim 1, further comprising: a
plurality of the tubes each of which defines therein the
refrigerant passage in which the first fluid flows, the tubes being
stacked in a stacking direction; and a plurality of outer fins each
of which is located between adjacent tubes.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is based on Japanese Patent Application No.
2007-303289 filed on Nov. 22, 2007, the contents of which are
incorporated herein by reference in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to a heat exchanger. The heat
exchanger can be suitably used as an intercooler for cooling intake
air to be supplied to an internal combustion engine, for
example.
BACKGROUND OF THE INVENTION
[0003] Conventionally, a heat exchanger such as an intercooler
performs heat exchange between cooling air and intake air to be
drawn into an internal combustion engine so as to cool the intake
air (for example, JP-A-2006-90305). The intercooler includes inner
fins inserted into tubes in which the intake air flows, thereby
promoting heat exchange between the intake air and the cooling air.
The inner fins have generally the same shape, that is, the same
specification from an intake air inlet side of the tubes to an
intake air outlet side thereof in the intercooler.
[0004] FIG. 8 shows a relationship between an intake air
temperature Tg in the tube and a distance H from an intake air
inlet of the tube in the intercooler, according to experiments by
the inventors of the present application. As shown in FIG. 8,
high-temperature intake air flowing from the intake air inlet of
the tube into the tube is drastically cooled in the tube, resulting
in a large difference in temperature of the intake air between the
intake air inlet side and the intake air outlet side of the tube.
That is, the temperature Tg of the intake air is rapidly reduced
from the intake air inlet of the tube as the distance H from the
intake air inlet of the tube increases. FIG. 9 shows a relationship
between a flow velocity Vg of intake air and the distance H from
the intake air inlet of the tube in the intercooler, according to
experiments by the inventors of the present application. As shown
in FIG. 9, the flow velocity Vg of intake air flowing from the
intake air inlet of the tube into the tube has a large difference
between the intake air inlet side and the intake air outlet side of
the tube. That is, the flow velocity Vg of the intake air is
rapidly reduced from the intake air inlet of the tube as the
distance H from the intake air inlet of the tube increases. At this
time, the use of the inner fins with the same specification from
the intake air inlet side to the outlet side as described above may
drastically increase the loss in pressure at the intake air inlet
side, resulting in reduction in heat exchange performance of the
whole intercooler.
[0005] Furthermore, as shown in FIG. 8, the temperature Tg of
intake air becomes very low on the intake air outlet side of the
tube, as compared to the intake air inlet side of the tube. Thus,
the difference in temperature between the intake air and the
cooling air becomes small on the intake-air outlet side, and
thereby it may be difficult to exchange heat between the intake air
and the cooling air. At this time, the use of the inner fins having
the same specification from the intake air inlet side to the intake
air outlet side described above may be difficult to effectively
perform heat exchange at the intake air outlet side of the
tube.
SUMMARY OF THE INVENTION
[0006] In view of the foregoing problems, it is an object of the
present invention to provide a heat exchanger which can effectively
improve heat exchange performance.
[0007] It is another object of the present invention to provide a
heat exchanger having a tube in which a plurality of fin portions
with different specifications are located in the tube.
[0008] According an aspect of the present invention, a heat
exchanger includes a tube having therein a flow passage through
which a first fluid flows, and an inner fin provided in the tube.
The tube is adapted to exchange heat between the first fluid and a
second fluid flowing through an outer periphery of the tube, and
the inner fin is located in the tube to promote the heat exchange
between the first fluid and the second fluid. The inner fin is
configured to divide the flow passage in the tube into a plurality
of flow paths. Furthermore, the inner fin includes a plurality of
fin portions with different specifications, and the fin portions
are arranged in series with respect to a flow direction of the
first fluid. In addition, the fin portion with the smallest flowing
resistance of the first fluid among the plurality of fin portions
is arranged on an upstream side of the flow direction of the first
fluid with respect to at least an another fin portion. Accordingly,
the heat exchange performance in the heat exchanger can be
effectively increased.
[0009] The phrase "the fin portion with the smallest flowing
resistance of the first fluid is arranged on the upstream side of
the flow direction of the first flow with respect to at least an
another fin portion" as used herein means not only that the fin
portion with the smallest flowing resistance of the first fluid is
arranged only on the upstream side of the first fluid flow with
respect to the other fin portions, but also the following case.
That is, the phrase also means that the fin portion with the
smallest flowing resistance of the first fluid is arranged on the
upstream side of the first fluid flow, and the fin portion with the
smallest flowing resistance of the first fluid may be also arranged
on the downstream side of the first fluid flow with respect to the
other fin portion. When the fin portion with the smallest flowing
resistance of the first fluid is arranged on the upstream side of
the flow direction of the first fluid with respect to at least an
another fin portion with a flowing resistance of the first fluid
larger than the smallest flowing resistance, the shape or the like
of the other fin portion(s) can be suitably changed.
[0010] For example, the fin portion with the largest flowing
resistance of the first fluid among the plurality of fin portions
may be arranged on a downstream side of the flow direction of the
first fluid with respect to the other fin portion.
[0011] Alternatively, the fin portions may be arranged
symmetrically with respect to a center line of the inner fin in the
flow direction of the first fluid. Furthermore, the fin portions
may be constructed of at least first and second different kinds of
fin portions. For example, the plurality of fin portions may
include a straight fin portion and a louver fin portion, and the
straight fin portion may be arranged on an upstream side of the
flow direction of the first fluid with respect to the louver fin
portion.
[0012] In this case, the straight fin portion may have a plurality
of wall surfaces extending linearly in the flow direction of the
first fluid, and the wall surfaces may be configured to divide the
flow passage of the tube into the plurality of flow paths.
Furthermore, the louver fin portion may include a plurality of flat
portions substantially in parallel to the flow direction of the
first fluid, and a plurality of louvers may be provided at the flat
portions along the flow direction of the first fluid. As an
example, the louvers may be formed by cutting and raising a part of
the flat portion.
[0013] Alternatively, the plurality of fin portions may include a
straight fin portion and an offset fin portion, and the straight
fin portion may be arranged on an upstream side of the flow
direction of the first fluid with respect to the offset fin
portion. In this case, straight fin portion has a plurality of wall
surfaces extending linearly in the flow direction of the first
fluid, and the wall surfaces are configured to divide the flow
passage of the tube into the plurality of flow paths. Furthermore,
the offset fin portion including wall portions are arranged in a
zigzag shape along the flow direction of the first fluid, and the
wall portions are configured to divide the flow passage of the tube
into the plurality of flow paths.
[0014] Alternatively, the inner fin may be a louver fin that
includes a plurality of flat portions substantially in parallel to
the flow direction of the first fluid, and a plurality of louvers
provided at the flat portions along the flow direction of the first
fluid. In this case, the fin portions are configured to have
different louver pitches in the louvers, and the fin portion with
the largest louver pitch among the plurality of fin portions is
arranged on an upstream side of the flow direction of the first
fluid with respect to at least an another fin portion.
[0015] Alternatively, in the heat exchanger, the fin portions may
have different fin pitches. In this case, the fin portion with the
largest fin pitch among the fin portions is arranged on an upstream
side of the flow direction of the first fluid, with respect to at
least an another fin portion.
[0016] In any above-described structure of the heat exchanger, the
fin portions may be continuously arranged in the flow direction of
the first fluid such that flow resistances of the first fluid in
the fin portions are increased as toward downstream in the flow
direction of the first fluid. Furthermore, in the heat exchanger,
the first fluid flowing in the tube generally may have a
temperature higher than that of the second fluid.
[0017] Furthermore, the heat exchanger may include a plurality of
the tubes stacked in a stacking direction, and a plurality of outer
fins each of which is located between adjacent tubes. As an
example, the first fluid is an intake air to be supplied to an
internal combustion engine, and the second fluid is a cooling
air.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Additional objects and advantages of the present invention
will be more readily apparent from the following detailed
description of preferred embodiments when taken together with the
accompanying drawings. In which:
[0019] FIG. 1 is a front view of an intercooler according to a
first embodiment of the present invention;
[0020] FIG. 2 is a cross sectional view taken along the line I-I in
FIG. 1;
[0021] FIG. 3 is a cross sectional view taken along the line II-II
in FIG. 2;
[0022] FIG. 4 is an enlarged perspective view showing an inner fin
in the first embodiment;
[0023] FIG. 5 is a sectional view showing an inner fin when being
viewed in a stacking direction of tubes according to a second
embodiment of the present invention;
[0024] FIG. 6 is an enlarged perspective view showing a third fin
portion of the inner fin in the second embodiment;
[0025] FIG. 7 is a sectional view showing an inner fin when being
viewed in a stacking direction of tubes according to a third
embodiment of the present invention;
[0026] FIG. 8 is a graph showing a relationship between an intake
air temperature Tg in a tube and a distance H from an intake air
inlet of the tube in an intercooler; and
[0027] FIG. 9 is a graph showing a relationship between a flow
velocity Vg of intake air in a tube and a distance H from an intake
air inlet of the tube in an intercooler.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
First Embodiment
[0028] A first embodiment of the present invention will be
described below with reference to FIGS. 1 to 4. A heat exchanger
according to the first embodiment of the present invention is
typically used for an intercooler. The intercooler is configured to
perform heat exchange between outside air (cooling air) and intake
air for combustion to be supplied into an internal combustion
engine, thereby to cool the intake air. The intake air is an
example of a first fluid of the present invention, and the cooling
air is an example of a second fluid of the present invention.
[0029] As shown in FIGS. 1 and 2, a core portion 1 of the
intercooler includes a plurality of stacked flat tubes 2 each
having a flow passage formed therein for allowing intake air to
flow therethrough, inner fins 3 disposed within the flat tubes 2,
and outer fins 4 each of which is disposed between the stacked flat
tubes 2. The flat tubes 2 are stacked in a tube stacking direction
that is perpendicular to the tube longitudinal direction and a flow
direction of the cooling air, as shown in FIGS. 1 and 2. In the
present embodiment, the tube 2 is made of copper or stainless
material, and both the inner fin 3 and the outer fin 4 are made of
copper, for example.
[0030] The outer fin 4 is formed in a wave-like shape (corrugated
shape) to be bonded to the outer wall surface of the tube 2, and
adapted to promote heat exchange between cooling air flowing
through between the tubes 2 and intake air flowing in the tubes 2.
The outer fin 4 is provided with louvers 4a formed by cutting and
raising a part of the fin to have a louver window shape in order to
prevent disturbance of air flow and growing of a temperature
interface layer.
[0031] The inner fin 3 is formed into a wave-like shape (corrugated
shape) to be bonded to the inner wall surface of the tube 2, and
adapted to promote heat exchange between the cooling air and intake
air. As shown in FIG. 4, the inner fin 3 includes a plurality of
wall surfaces 3a each of which extends to connect opposite wall
surfaces of the tubes 2. A flow passage in the tube 2 is divided
into a plurality of thin wall flow paths 20 by the wall surfaces 3a
of the inner fin 3, as shown in FIGS. 2 and 4. The detailed
structure of the inner fin 3 will be described later.
[0032] Header tanks 5 and 6 are provided on both end sides of the
tubes 2 in the tube longitudinal direction, to extend in the
stacking direction of the tubes 2. Each of the header tanks 5 and 6
is located to communicate with the respective tubes 2. One header
tank 5 has an inlet 50 connected to a supercharger, from which
intake air pressure-fed is introduced. The intake air flowing into
the header tank 5 from the inlet 50 is distributed among and flows
into the respective tubes 2. The other header tank 6 has an outlet
60 connected to an intake port of the internal combustion engine.
The other header tank 6 is adapted to collect and recover intake
air flowing from the tubes 2, so as to feed the air to an intake
port of the internal combustion engine. Both header tanks 5 and 6
can be made of a metal such as copper.
[0033] FIG. 2 is a cross sectional view taken along the line I-I in
FIG. 1, FIG. 3 is a cross sectional view taken along the line II-II
in FIG. 2, and FIG. 4 is an enlarged perspective view showing the
inner fin 3 in the first embodiment.
[0034] The inner fin 3 of the present embodiment shown in FIGS. 3
and 4 is formed by applying a roller forming method to a thin
metallic material. The inner fin 3 includes the wall surfaces 3a
extending substantially in parallel to the flow direction of the
intake air in the tube 2, and top parts 3b connecting the adjacent
wall surfaces 3a. The inner fin 3 is formed in a corrugated shape
when being viewed from the flow direction of the intake air. A
plurality of the wall surfaces 3a are arranged in the flow
direction of cooling air (e.g., in the width direction of the tube
2), as shown in FIG. 2. The wall surface 3a may be a flat surface
as shown in FIG. 4.
[0035] The inner fin 3 of the present embodiment includes two
different kinds of fin portions 31 and 32. These two fin portions
31 and 32 are arranged continuously in series in the flow direction
of the intake air. One of the two fin portions 31 and 32 which is
arranged on the upstream side in the intake-air flow direction is
hereinafter referred to as the first fin portion 31, whereas the
other arranged on the downstream side in the intake-air flow
direction is hereinafter referred to as the second fin portion 32.
In the present embodiment, the first fin portion 31 and the second
fin portion 32 are continuously formed to be integrated as one
inner fin.
[0036] The second fin portion 32 is a louver fin having a plurality
of louvers 321. Specifically, the wall surface 3a of the second fin
portion 32 is integrally formed with the louvers 321 each of which
has a louver window shape by cutting and raising a part of the wall
surface 3a. Each louver 321 is formed by being bent and twisted at
a predetermined twist angle with respect to the wall surface 3a as
being viewed in the stacking direction of the tubes 2. A plurality
of louvers 321 are provided in the wall surface 3a along the flow
direction of the intake air. A louver-to-louver passage 322 is
formed between the adjacent louvers 321.
[0037] The second fin portion 32 of the present embodiment includes
turning portions 323 each reversing the twisting direction of the
louver 321, as shown in FIG. 3. Each turning portion 323 is
positioned at a center portion of the second louver portion 32 in
the flow direction of the intake air.
[0038] The first fin portion 31 does not have any louver 321, and
is a straight fin including a wall surface 30 linearly extending in
the flow direction of the intake air. Thus, a flowing resistance of
intake air in the first fin portion 31 (hereinafter referred to as
an "air flowing resistance") is smaller than that in the second fin
portion 32 with the louvers 321.
[0039] The intake air inlet side, that is, the most upstream side
of the intake air flow in the tube 2 has an intake air temperature
higher than that of other parts thereof, thereby making a flow
velocity of intake air on the inlet side higher than that of the
other parts. For this reason, providing the inner fin 3 in the tube
2 may lead to the largest loss of pressure on the intake air inlet
side. Thus, in the present embodiment, the first fin portion 31
which is the straight fin having the small air flowing resistance
is disposed on the intake air inlet side in the tube 2, and thereby
it can reduce the loss in pressure on the intake air inlet side of
the tube 2.
[0040] At this time, since the first fin portion 31 having the
small air flowing resistance has relatively low heat exchange
performance, the heat exchange performance on the intake air inlet
side of the tube 2 may be relatively reduced in the intercooler 1.
The intake air inlet side of the tube 2, however, can sufficiently
have a difference in temperature between the intake air and cooling
air, and thereby it can suppress the reduction in heat exchange
performance on the intake air inlet side of the tube 2 to a very
small level. That is, the reduction in heat exchange performance of
the intake air inlet side of the tube 2 due to reduction in heat
exchange performance of the first fin portion 31 is very small, as
compared to the increase of the heat exchange performance of the
entire intercooler due to reduction in loss of pressure on the
intake air inlet side of the tube 2.
[0041] Thus, in the present embodiment, the shape of the first fin
portion 31 is not limited to the straight line shape shown in FIG.
1, but may be suitably changed. For example, a first fin portion 31
having an air flowing resistance smaller than that of the second
fin portion 32 can be arranged on the intake air inlet side within
the tube 2. Even in this case, the heat exchange performance of the
entire heat exchanger can be effectively improved.
[0042] The intake air outlet side, that is, the most downstream
side of the intake air flow, in the tube 2 has an intake air
temperature lower than that of the other parts thereof, resulting
in a small difference in temperature between the intake air and the
cooling air, making it difficult to perform heat exchange. Thus,
the second fin portion 32 which is a louver fin having a large air
flowing resistance (or having high heat exchange performance) is
disposed on the intake air outlet side of the tube 2, and thereby
it can improve the heat exchange performance on the intake air
outlet side of the tube 2.
[0043] At this time, the air flowing resistance is increased on the
intake air outlet side of the tube 2. The intake air temperature on
the intake air output side of the tube 2 is low and thus the flow
velocity of the intake air is low, so that it can suppress the
amount of increase in loss of pressure on the intake air output
side of the tube 2 to a very small level. That is, the reduction in
heat exchange performance of the entire intercooler due to an
increase in loss of pressure on the intake air outlet side of the
tube 2 is very small, as compared to improvement of the heat
exchange performance by disposing the second fin portion 32 having
the large air flowing resistance on the intake air output side of
the tube 2.
[0044] Thus, according to the present embodiment, because the
second fin portion 32 having the air flowing resistance larger than
that of the first fin portion 31 is disposed on the intake air
outlet side of the tube 2, it can further effectively improve the
heat exchange performance in the entire heat exchanger. That is,
the second fin portion 32 is configured to have the higher heat
exchange performance between the intake air and the cooling air in
the intercooler 1, than that of the first fin portion 31, the
shapes of the first fin portion 31 and the second fin portion 32
can be suitably changed.
Second Embodiment
[0045] A second embodiment of the present invention will be
described below based on FIGS. 5 and 6. The same components as
those in the first embodiment are designated by the same reference
numerals, and a description thereof will be omitted below. FIG. 5
is a sectional view of the inner fin 3 of the second embodiment
when being viewed in the stacking direction of the tubes 2. FIG. 5
of the second embodiment is a drawing corresponding to FIG. 3.
[0046] As shown in FIG. 5, an inter fin 3 of the present embodiment
includes three different kinds of fin portions 31 to 33. The three
fin portions 31 to 33, namely, the first fin portion 31, the third
fin portion 33, and the second fin portion 32 are arranged
continuously in that order from the upstream side of the intake air
flow. The first fin portion 31 is a straight fin similar to that in
the first embodiment. The second fin portion 32 is a louver fin
similar to that in the first embodiment.
[0047] FIG. 6 is an enlarged perspective view showing the third fin
portion 33 in the second embodiment. As shown in FIG. 6, the third
fin portion 33 of the present embodiment has a corrugated sectional
shape in cross section substantially perpendicular to the flow
direction of the intake air, or when being viewed in the flow
direction of the intake air. The sectional shape is formed by
alternately positioning and bending convex portions 331 on one side
and on the other side. The third fin portion 33 includes cut-up
portions 332 formed by partially cutting and raising the fin 33 in
the flow direction of the intake air. The third fin portion 33 is
an offset fin in which wave-shaped portions formed by the cut-up
portions 332 are offset by adjacent wave-shaped portions in the
intake-air flowing direction when being viewed in the intake-air
flowing direction. The convex portions 331 of the third fin portion
33 are located in contact with the inner wall surface of the tube
2.
[0048] The inside of the tube 2 is divided into a plurality of flow
paths by the third fin portion 33. The flow paths divided in the
tube 2 are partially offset in the intake-air flowing direction.
That is, wall portions 333 for dividing the inside of the tube 2
into the flow paths are arranged in a zigzag shape along the
intake-air flowing direction. Upon viewing the third fin portion 33
in the intake-air flowing direction, the concave portions 331 are
adjacent to each other on the same side, that is, on one side and
on the other side, in the intake-air flowing direction. The concave
portions 31 are positioned so as to be offset from each other.
[0049] Returning now to FIG. 5, the first fin portion 31 serving as
the straight fin has the smaller air flowing resistance than that
of each of the second fin portion 32 serving as the louver fin and
the third fin portion 33 serving as the offset fin. In other words,
in the inner fin 3, the first fin portion 31 has the smallest air
flowing resistance. In the present embodiment, the second fin
portion 32 has the higher heat exchange performance, but the larger
air flowing resistance, as compared to that of the third fin
portion 33. That is, the first fin portion 31 is configured to have
an air flowing resistance, the third fin portion 33 is configured
to have an air flowing resistance larger than that of the first fin
portion 31, and the second fin portion 32 is configured to have an
air flowing resistance larger than that of the third fin portion
33.
[0050] Even this arrangement of the second embodiment, the entire
heat exchanging performance can be effectively improved similarly
to the above-mentioned first embodiment.
Third Embodiment
[0051] A third embodiment of the present invention will be
described below based on FIG. 7. The same components as those in
the first embodiment are designated by the same reference numerals,
and a description thereof will be omitted below. FIG. 7 is a
sectional view showing an inner fin 3 of the third embodiment when
being viewed in the stacking direction of tubes 2. FIG. 7 is a
diagram corresponding to the diagram of FIG. 3.
[0052] As shown in FIG. 7, the inner fin 3 of the present
embodiment includes two first fin portions 31 each of which is a
straight fin similar to that of the first embodiment, and a second
fin portion 32 which is a louver fin similar to that of the first
embodiment. The two first fin portions 31 are disposed one by one
on the upstream and downstream sides of the second fin portion 32
in the flow direction of intake air. In other words, the second fin
portion 31is disposed between the two first fin portions 31 in the
flow direction of the intake air.
[0053] The two first fin portions 31 may be set to have
substantially the same length in the flow direction of the intake
air. The second fin portion 32 has substantially a symmetric shape
with respect to a center line L1 in the intake-air flowing
direction. Thus, the inner fin 3 of the present embodiment has
substantially a symmetric shape with respect to a center line L2 of
the entire inner fin 3 in the intake-air flowing direction. That
is, the first and second fin portions 31 and 32 are disposed so as
to be symmetrical to each other with respect to the center line L2
of the inner fin 3 in the intake-air flowing direction. At this
time, the center line L1 of the second fin portion 32 in the
intake-air flowing direction is substantially the same as the
center line L2 of the inner fin 3 in the intake-air flowing
direction.
[0054] The intercooler with this arrangement can prevent the wrong
assembly of the inner fin 3 to the tube 2, while obtaining the same
effects as those of the first embodiment.
Other Embodiments
[0055] Although the present invention has been fully described in
connection with the preferred embodiments thereof with reference to
the accompanying drawings, it is to be noted that various changes
and modifications will become apparent to those skilled in the
art.
[0056] For example, in each of the above-mentioned embodiments, the
different kinds of fin portions 31 to 33 are employed as fin
portions with different specifications, the present invention is
not limited thereto. The fin portions with different specifications
may be constructed by setting the same kind of fins to have
different respective fin pitches. In this case, a fin portion with
the largest fin pitch among the fin portions is disposed on the
upstream side of the intake-air flowing direction with respect to
at least the other fin portions, thereby reducing the loss in
pressure on the intake air inlet side of the tube 2. As a result,
the entire intercooler can have an improved heat exchange
performance.
[0057] Fin portions with different specifications may be
constructed by employing the louver fin as the inner fin 3 and by
setting the louver fins to have different louver pitches. In this
case, a fin portion with the largest louver pitch among the fin
portions is disposed on the upstream side of the intake-air flowing
direction with respect to at least the other fin portions, so as to
reduce the loss in pressure on the intake air inlet side of the
tube 2. As a result, the entire intercooler can have improved heat
exchange performance.
[0058] Although in the first and third embodiments the louver fin
is used as the second fin 32, the present invention is not limited
thereto. Alternatively, an offset fin may be used as the second fin
32.
[0059] In the second embodiment, the first fin portion 31, the
third fin portion 33, and the second fin portion 32 are arranged in
that order from the upstream side of the intake air flow. However,
the first fin portion 31, the second fin portion 32, and the third
fin portion 33 may be arranged in that order from the upstream side
of the intake air flow.
[0060] Furthermore, the above embodiments of the present invention
may be suitably combined without being limited to the
above-described example.
[0061] For example, according an aspect of the above described
embodiments and modifications of the present invention, a heat
exchanger includes a tube 2 having therein a flow passage through
which a first fluid flows, and an inner fin 3 provided in the tube
2. The tube 2 is adapted to exchange heat between the first fluid
and a second fluid flowing through an outer periphery of the tube
2, and the inner fin 3 is located in the tube 2 to promote the heat
exchange between the first fluid and the second fluid. The inner
fin 3 is configured to divide the flow passage in the tube 2 into a
plurality of flow paths 20. Furthermore, the inner fin 3 includes a
plurality of fin portions (31, 32, 33) with different
specifications, and the fin portions (31, 32, 33) are arranged in
series with respect to a flow direction of the first fluid. In
addition, the fin portion (31) with the smallest flowing resistance
of the first fluid among the plurality of fin portions (31, 32, 33)
is arranged on an upstream side of the flow direction of the first
fluid with respect to at least an another fin portion (32, 33).
Accordingly, the heat exchange performance in the heat exchanger
can be effectively increased.
[0062] The phrase "the fin portion (31) with the smallest flowing
resistance of the first fluid is arranged on the upstream side of
the flow direction of the first flow with respect to at least an
another fin portion (32, 33)" as used herein means not only that
the fin portion (31) with the smallest flowing resistance of the
first fluid is arranged only on the upstream side of the first
fluid flow with respect to the other fin portions (32, 33), but
also the following case. That is, the phrase also means that the
fin portion (31) with the smallest flowing resistance of the first
fluid is arranged on the upstream side of the first fluid flow, and
the fin portion (31) with the smallest flowing resistance of the
first fluid may be also arranged on the downstream side of the
first fluid flow with respect to the other fin portions (32, 33).
When the fin portion (31) with the smallest flowing resistance of
the first fluid is arranged on the upstream side of the flow
direction of the first fluid with respect to at least an another
fin portion (32, 33) with a flowing resistance of the first fluid
larger than the smallest flowing resistance, the specification such
as the shape of the other fin portion(s) (32, 33) can be suitably
changed.
[0063] For example, the fin portion (31) with the largest flowing
resistance of the first fluid among the plurality of fin portions
(31, 32, 33) may be arranged on a downstream side of the flow
direction of the first fluid with respect to the other fin portion
(32, 33).
[0064] Alternatively, the fin portions (31, 32, 33) may be arranged
symmetrically with respect to a center line L2 of the inner fin in
the flow direction of the first fluid. Furthermore, the fin
portions (31, 32, 33) may be constructed of at least first and
second different kinds of fin portions. For example, the plurality
of fin portions (31, 32, 33) may include a straight fin portion 31
and a louver fin portion 32, and the straight fin portion 31 is
arranged on an upstream side of the flow direction of the first
fluid with respect to the louver fin portion 32. In this case, the
straight fin portion 31 may have a plurality of wall surfaces 30
extending linearly in the flow direction of the first fluid, and
the wall surfaces 30 may be configured to divide the flow passage
of the tube into the plurality of flow paths. Furthermore, the
louver fin portion may include a plurality of flat portions 3a
substantially in parallel to the flow direction of the first fluid,
and a plurality of louvers 321 may be provided at the flat portions
3a along the flow direction of the first fluid. As an example, the
louvers 321 may be formed by cutting and raising a part of the flat
portion.
[0065] Alternatively, the plurality of fin portions (31, 32, 33)
may include a straight fin portion 31 and an offset fin portion 33,
and the straight fin portion 31 may be arranged on an upstream side
of the flow direction of the first fluid with respect to the offset
fin portion 33. In this case, the straight fin portion 31 has a
plurality of wall surfaces 30 extending linearly in the flow
direction of the first fluid, and the wall surfaces 30 are
configured to divide the flow passage of the tube 2 into the
plurality of flow paths. Furthermore, the offset fin portion 33
including wall portions 333 are arranged in a zigzag shape along
the flow direction of the first fluid, and the wall portions 333
are configured to divide the flow passage of the tube 2 into the
plurality of flow paths.
[0066] Alternatively, the inner fin may be a single louver fin
including a plurality of flat portions 3a substantially in parallel
to the flow direction of the first fluid, and a plurality of
louvers 321 provided at the flat portions 3a along the flow
direction of the first fluid. In this case, the fin portions are
configured to have different louver pitches in the louvers 321, and
the fin portion with the largest louver pitch among the plurality
of fin portions 321 is arranged on an upstream side of the flow
direction of the first fluid with respect to at least an another
fin portion.
[0067] Alternatively, in the heat exchanger, the fin portions may
have different fin pitches. In this case, the fin portion with the
largest fin pitch among the fin portions is arranged on an upstream
side of the flow direction of the first fluid, with respect to at
least an another fin portion.
[0068] In any above-described structure of the heat exchanger, the
fin portions (31, 32, 33) may be continuously arranged in the flow
direction of the first fluid such that flow resistances of the
first fluid in the fin portions (31, 32, 33) are increased as
toward downstream in the flow direction of the first fluid.
Furthermore, in the heat exchanger, the first fluid flowing in the
tube 2 generally may have a temperature higher than that of the
second fluid. For example, the first fluid is an intake air to be
supplied to an internal combustion engine, and the second fluid is
a cooling air (i.e., outside air).
[0069] Such changes and modifications are to be understood as being
within the scope of the present invention as defined by the
appended claims.
* * * * *