U.S. patent application number 13/135661 was filed with the patent office on 2012-02-02 for intercooler.
This patent application is currently assigned to DENSO CORPORATION. Invention is credited to Masaki Harada.
Application Number | 20120024511 13/135661 |
Document ID | / |
Family ID | 45525523 |
Filed Date | 2012-02-02 |
United States Patent
Application |
20120024511 |
Kind Code |
A1 |
Harada; Masaki |
February 2, 2012 |
Intercooler
Abstract
An inner fin arranged in a flat tube has a wave shape
constructed by alternately connecting first walls and second walls.
The first wall connects two of the second walls in a connecting
direction. The first wall has a protrusion with an extending
dimension in the connecting direction and a protruding dimension
protruding from the first wall. A ratio of the extending dimension
to a height dimension of the first wall is defined as a length
ratio x/Fh, and a ratio of the protruding dimension to a width
dimension of the second wall is defined as a protrusion ratio y/Fw.
The ratios x/Fh, y/Fw are set to have values having a predetermined
relationship.
Inventors: |
Harada; Masaki; (Anjo-city,
JP) |
Assignee: |
DENSO CORPORATION
Kariya-city
JP
|
Family ID: |
45525523 |
Appl. No.: |
13/135661 |
Filed: |
July 12, 2011 |
Current U.S.
Class: |
165/181 |
Current CPC
Class: |
F28F 13/02 20130101;
Y02T 10/12 20130101; F28F 2215/10 20130101; F02B 29/0456 20130101;
F28F 1/126 20130101; F28F 3/025 20130101; Y02T 10/146 20130101;
F28D 1/05366 20130101 |
Class at
Publication: |
165/181 |
International
Class: |
F28F 1/10 20060101
F28F001/10 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 27, 2010 |
JP |
2010-168478 |
Claims
1. An intercooler comprising: a flat tube, intake air to be drawn
into an engine passing through the flat tube and being cooled by
external fluid, the flat tube having two major faces opposing with
each other in a thickness direction; and an inner fin arranged
inside of the flat tube, the inner fin having a wave-shaped
cross-section constructed by alternately connecting a plurality of
first walls and a plurality of second walls in a major direction
approximately perpendicular to the thickness direction, the second
wall being approximately parallel with the two major faces, the
first wall connecting two of the second walls in a connecting
direction corresponding to the thickness direction, wherein the
first wall linearly extends in a flowing direction of the intake
air that is approximately perpendicular to the connecting direction
and the major direction, the first wall has a protrusion protruding
in the major direction and being located at a middle position in
the connecting direction, the protrusion is defined to have an
extending dimension (x) in the connecting direction, and a
protruding dimension (y) protruding from a face of the first wall
in the major direction, the first wall is defined to have a height
dimension (Fh) in the connecting direction, and the second wall is
defined to have a width dimension (Fw) in the major direction, a
ratio of the extending dimension to the height dimension is defined
as a length ratio (x/Fh), and a ratio of the protruding dimension
to the width dimension is defined as a protrusion ratio (y/Fw), the
length ratio (x/Fh) is applied to a lateral axis of a two-axis
coordinate, and the protrusion ratio (y/Fw) is applied to a
vertical axis of the two-axis coordinate, and the length ratio
(x/Fh) and the protrusion ratio (y/Fw) are set to have values in an
area surrounded by the vertical axis and lines connecting a point
(x/Fh, y/Fw=0, 0), a point (x/Fh, y/Fw=0.89, 0.05), a point (x/Fh,
y/Fw=1.0, 0.1), a point (x/Fh, y/Fw=0.87, 0.15), a point (x/Fh,
y/Fw=0.77, 0.2), a point (x/Fh, y/Fw=0.64, 0.25), and a point
(x/Fh, y/Fw=0, 0.4) in this order.
2. The intercooler according to claim 1, wherein the length ratio
(x/Fh) is set to have a value of 0.1, and the protrusion ratio
(y/Fw) is set to have a value in a range of 0.43-0.87.
3. The intercooler according to claim 1, wherein the protrusion
protrudes on a first side in the major direction by pressing the
first wall from a second side opposite from the first side in the
major direction.
4. The intercooler according to claim 1, wherein the protrusion is
long in the connecting direction and is narrow in the flowing
direction of the intake air.
5. The intercooler according to claim 4, wherein the protrusion has
an ellipse shape that is long in the connecting direction and is
narrow in the flowing direction of the intake air.
6. The intercooler according to claim 1, wherein the protrusion is
one of a plurality of protrusions arranged in the connecting
direction.
7. An intercooler comprising: a flat tube, intake air to be drawn
into an engine passing through the flat tube and being cooled by
external fluid, the flat tube having two major faces opposing with
each other in a thickness direction; and an inner fin arranged
inside of the flat tube, the inner fin having a wave-shaped
cross-section constructed by alternately connecting a plurality of
first walls and a plurality of second walls in a major direction
approximately perpendicular to the thickness direction, the second
wall being approximately parallel with the two major faces, the
first wall connecting two of the second walls in a connecting
direction corresponding to the thickness direction, wherein the
first wall linearly extends in a flowing direction of the intake
air that is approximately perpendicular to the connecting direction
and the major direction, and the second wall has a protrusion
protruding from an inner face of the second wall toward an opening
side of the inner fin having the wave-shaped cross-section.
8. The intercooler according to claim 7, wherein the protrusion is
produced by pressing the second wall toward a center of the flat
tube.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is based on Japanese Patent Application No.
2010-168478 filed on Jul. 27, 2010, the disclosure of which is
incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to an intercooler.
[0004] 2. Description of Related Art
[0005] JP-A-2006-90305 (US 2006/0042607 A1) describes an
intercooler having a tube and an inner fin arranged in the tube.
The inner fin has a wavy cross-section, and the wavy cross-section
of the inner fin partitions inside of the tube into passages. The
inner fin linearly extends in a flowing direction of intake air, so
that the inner fin is called as a straight fin.
[0006] The inner fin is constructed by alternately connecting first
walls and second walls. The first wall partitions the inside of the
tube into the passages, and a face of the second wall is fixed to
an inner face of the tube. Both of the first wall and the second
wall are constructed by simple planes.
[0007] The straight fin has a comparatively small flow resistance
when intake air flows through the passages, so that a pressure loss
of the intercooler is low. However, a boundary layer of intake air
flow is easily generated on each face of the first wall and the
second wall. In this case, a heat radiating property of the
intercooler may be lowered.
SUMMARY OF THE INVENTION
[0008] In view of the foregoing and other problems, it is an object
of the present invention to provide an intercooler.
[0009] According to a first example of the present invention, an
intercooler includes a flat tube and an inner fin arranged inside
of the flat tube. While intake air to be drawn into an engine
passes through the flat tube, the intake air is cooled by external
fluid. The flat tube has two major faces opposing with each other
in a thickness direction. The inner fin has a wave-shaped
cross-section constructed by alternately connecting first walls and
second walls in a major direction approximately perpendicular to
the thickness direction. The second wall is approximately parallel
with the two major faces. The first wall connects two of the second
walls in a connecting direction corresponding to the thickness
direction. The first wall linearly extends in a flowing direction
of the intake air that is approximately perpendicular to the
connecting direction and the major direction. The first wall has a
protrusion protruding in the major direction and the protrusion is
located at a middle position in the connecting direction. The
protrusion is defined to have an extending dimension (x) in the
connecting direction, and a protruding dimension (y) protruding
from a face of the first wall in the major direction. The first
wall is defined to have a height dimension (Fh) in the connecting
direction, and the second wall is defined to have a width dimension
(Fw) in the major direction. A ratio of the extending dimension to
the height dimension is defined as a length ratio (x/Fh), and a
ratio of the protruding dimension to the width dimension is defined
as a protrusion ratio (y/Fw). When the length ratio (x/Fh) is
applied to a lateral axis of a two-axis coordinate, and when the
protrusion ratio (y/Fw) is applied to a vertical axis of the
two-axis coordinate, the length ratio (x/Fh) and the protrusion
ratio (y/Fw) are set to have values in an area surrounded by the
vertical axis and lines connecting a point (x/Fh, y/Fw=0, 0), a
point (x/Fh, y/Fw=0.89, 0.05), a point (x/Fh, y/Fw=1.0, 0.1), a
point (x/Fh, y/Fw=0.87, 0.15), a point (x/Fh, y/Fw=0.77, 0.2), a
point (x/Fh, y/Fw=0.64, 0.25), and a point (x/Fh, y/Fw=0, 0.4) in
this order.
[0010] Accordingly, heat radiating property of the intercooler can
be raised.
[0011] According to a second example of the present invention, an
intercooler includes a flat tube and an inner fin arranged inside
of the flat tube. While intake air to be drawn into an engine
passes through the flat tube, the intake air is cooled by external
fluid. The flat tube has two major faces opposing with each other
in a thickness direction. The inner fin has a wave-shaped
cross-section constructed by alternately connecting first walls and
second walls in a major direction approximately perpendicular to
the thickness direction. The second wall is approximately parallel
with the two major faces. The first wall connects two of the second
walls in a connecting direction corresponding to the thickness
direction. The first wall linearly extends in a flowing direction
of the intake air that is approximately perpendicular to the
connecting direction and the major direction. The second wall has a
protrusion protruding from an inner face of the second wall inward
in the connecting direction.
[0012] Accordingly, heat radiating property of the intercooler can
be raised.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The above and other objects, features and advantages of the
present invention will become more apparent from the following
detailed description made with reference to the accompanying
drawings. In the drawings:
[0014] FIG. 1 is a schematic front view illustrating an intercooler
according to a first embodiment;
[0015] FIG. 2 is a schematic cross-sectional view taken along line
II-II of FIG. 1;
[0016] FIG. 3 is a perspective view illustrating a protrusion of an
inner fin of the intercooler;
[0017] FIG. 4A is a front view illustrating the protrusion, and
FIG. 4B is a side view illustrating the protrusion;
[0018] FIG. 5 is a side view illustrating a height dimension of the
intercooler and an extending dimension of the protrusion;
[0019] FIG. 6 is a front view illustrating a width dimension of the
intercooler and a protruding dimension of the protrusion;
[0020] FIG. 7 is a graph illustrating a relationship between a
length ratio and a density ratio of supercharged air;
[0021] FIG. 8 is a graph illustrating a relationship between the
length ratio and a protrusion ratio;
[0022] FIG. 9A is a simulation model illustrating a flowing
velocity distribution of intake air in a tube of the intercooler,
and FIG. 9B is a simulation model illustrating a flowing velocity
distribution of intake air in a tube of an intercooler of a
comparison example;
[0023] FIGS. 10A-10D are views respectively illustrating
modifications of the protrusion according to a second
embodiment;
[0024] FIG. 11 is a schematic perspective view illustrating a
protrusion of an inner fin of an intercooler according to a third
embodiment; and
[0025] FIG. 12 is a front view illustrating an intercooler
according to other embodiment.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENT
First Embodiment
[0026] A first embodiment will be described with reference to FIGS.
1-9B. As shown in FIG. 1, an air-cooled type intercooler 100A has a
few number of tubes 111, and the tubes 111 are comparatively
long.
[0027] Intake air is compressed by a turbocharger (not shown), and
the compressed air is drawn into an engine (not shown) of a
vehicle. The intake air may be hereinafter referred as supercharged
air. The intercooler 100A is a heat exchanger to cool the intake
air by exchanging heat with cool air corresponding to external
fluid. The intercooler 100A mainly has a core part 110 and a pair
of header tanks 120, 130. Each component of the intercooler 100A is
made of aluminum or aluminum alloy which is excellent in thermal
conductivity. The intercooler 100A is produced by brazing, welding
or swaging its components.
[0028] The core part 110 is constructed by alternately layering the
tubes 111 and outer fins 112. An inner fin 114 is arranged in the
tube 111. A side plate 113 is arranged on the outer fin 112 located
most outside.
[0029] Intake air passes through the tube 111, and the tube 111 has
a flat rectangular cross-section, as shown in FIG. 2. A
cross-sectional area of the tube 111 is made large as much as
possible within a limited space, so as to reduce a flow resistance
of intake air.
[0030] The flat tube 111 has two major faces 111a and two minor
faces 111b. The major face 111a is approximately parallel with a
major side of the flat cross-section, and the minor face 111b is
approximately parallel with a minor side of the flat cross-section.
An inner face of the tube 111 is defined as a tube inner face 111c.
The major side of the flat cross-section is defined to extend in a
major direction.
[0031] The outer fin 112 is produced to have a wave shape by
processing a thin plate material. Plural louvers 112a are defined
in a plane part of the outer fin 112 by cutting and bending. The
outer fin 112 increases an area of radiating (exchanging) heat
toward cool air. Further, turbulent effects are generated by the
louvers 112a so as to promote the heat exchange with intake air. A
dimension of the outer fin 112 in a flowing direction of cool air
is set approximately equal with that of the tube 111.
[0032] The side plate 113 is a strengthening member extending in a
longitudinal direction of the tube 111. The side plate 113 has an
approximately U-shape cross-section, and is arranged on the outer
fin 112 located most outside in a tube layering direction. Open
side of the U-shape cross-section of the side plate 113 is located
outside and opposite from the tube 111 and the outer fin 112.
[0033] A mountain (top) part of the outer fin 112 having the wave
shape is contact and connected with the major face 111a of the tube
111. The outer fin 112 located most outside is contact and
connected with the side plate 113.
[0034] As shown in FIG. 1, the header tank 120, 130 is disposed at
an end of the tube 111 in the tube longitudinal direction. The tank
120, 130 extends in the tube layering direction, and communicates
with each of the tubes 111. The header tank 120 has a header plate
121, a tank part 122, and an inlet pipe 123. The header tank 130
has a header plate 131, a tank part 132, and an outlet pipe
133.
[0035] The header plate 121, 131 has a burring around an outer
periphery, and has a tube hole at a position corresponding to the
tube 111. The burring has plural swaging nails, and the tank part
122, 132 is mechanically connected to the burring by swaging the
nails. The end of the tube 111 is inserted and fitted with the tube
hole. The tube 111 and the header plate 121, 131 are contact and
connected with each other. An end of the side plate 113 in a
longitudinal direction is contact and connected to the header plate
121, and the other end of the side plate 113 is contact and
connected to the header plate 131.
[0036] The tank part 122, 132 is a semi-container open to the
header plate 121, 131. The open side of the tank part 122, 132 is
located on an inner side of the burring of the header plate 121,
131. A seal member (not shown) is interposed between the header
plate 121, 131 and the tank part 122, 132. The tank part 122, 132
is connected to the header plate 121, 131 by swaging the nails of
the header plate 121, 131.
[0037] The pipe 123, 133 is a communication portion that makes an
inside of the tank part 122, 132 to communicate with outside. The
pipe 123, 133 is integrated with the tank part 122, 132. Intake air
flows into the tank part 122 through the inlet pipe 123, and is
discharged out of the tank part 132 through the outlet pipe
133.
[0038] The inner fin 114 is disposed inside the tube 111. The inner
fin 114 increases an area of exchanging heat with intake air
flowing through the tube 111, so as to promote heat exchange. The
inner fin 114 is produced to have a waveform by processing a thin
plate material. Because the tube 111 has the flat rectangular
cross-section, the inner fin 114 is efficiently arranged in the
tube 111 without creating a dead space.
[0039] As shown in FIG. 2, the inner fin 114 has a first wall 114a
and a second wall 114b. The first wall 114a connects the second
walls 114b in a connecting direction corresponding to an
up-and-down direction of FIG. 2. The major faces 111a of the tube
111 oppose to each other in the connecting direction, and the first
wall 114a extends in the connecting direction. The second wall 114b
is approximately parallel with the major face 111a of the tube 111,
and extends in the major direction corresponding to a
left-and-right direction of FIG. 2.
[0040] As shown in FIG. 3, an end of the second wall 114b is
connected to the first wall 114a, and the other end of the second
wall 114b is connected to another first wall 114a. The inner fin
114 has the waveform by alternately connecting the first walls 114a
and the second walls 114b in the major direction. The first wall
114a extends approximately perpendicularly to the major face 111a
in a manner that the connecting direction corresponds to a
thickness direction of the flat tube 111. In this case, the
waveform of the inner fin 114 is rectangle or square.
Alternatively, the connecting direction may be inclined with
respect to the thickness direction. In this case, the waveform of
the inner fin 114 is trapezoid.
[0041] The inner fin 114 is so-called straight type fin. The first
wall 114a linearly extends in a flowing direction of intake air
represented by a blank arrow direction in FIGS. 3 and 4B. The first
wall 114a is arranged in the tube 111 so as to connect the major
faces 111a opposing with each other, so that an inside of the tube
111 is divided into plural passages.
[0042] The second wall 114b linearly extends in the flowing
direction of intake air, similarly to the first wall face 114a. A
face of the second wall 114b is contact and connected to the tube
inner face 111c. A width dimension of the first wall 114a in the
connecting direction is set longer than a width dimension of the
second wall 114b in the major direction, and each passage is longer
in the connecting direction than in the major direction.
[0043] As shown in FIG. 3, the first wall 114a has a protrusion
114c, 114d at a middle position in the connecting direction. For
example, the protrusion 114c, 114d is located at. a central
position in the connecting direction. The protrusion 114c protrudes
leftward in the major direction from the first wall 114a in FIG. 3,
and the protrusion 114d protrudes rightward in the major direction
from the first wall 114a in FIG. 3. Inside of the protrusion 114c,
114d is recessed in the same direction. When the first wall 114a is
seen from front, the protrusion 114c, 114d extends in the
connecting direction. Specifically, the protrusion 114c, 114d has
an ellipse shape, as shown in FIG. 4B and 5.
[0044] The protrusions 114c and the protrusions 114d are
alternately arranged in the flowing direction of intake air, on the
single first wall 114. When the first walls 114a oppose to each
other in the major direction, positions of the protrusions 114c
correspond with each other in the major direction, and positions of
the protrusions 114d correspond with each other in the major
direction.
[0045] As shown in FIG. 5, the first wall 114a of the inner fin 114
is defined to have a height dimension Fh in the connecting
direction, and the protrusion 114c, 114d is defined to have an
extending dimension x in the connecting direction. As shown in FIG.
6, the second wall 114b is defined to have a width dimension Fw in
the major direction, and the protrusion 114c, 114d is defined to
have a protruding dimension y protruding from the first wall 114a
in the major direction.
[0046] A length ratio x/Fh is defined as a ratio of the extending
dimension x to the height dimension Fh. A protrusion ratio y/Fw is
defined as a ratio of the protruding dimension y to the width
dimension Fw. The length ratio x/Fh and the protrusion ratio y/Fw
are set to have values within a hatched area of FIG. 8. When the
inner fin 114 is defined to have a fin pitch Fp between mountain
parts of the wave shape located adjacent to each other, the width
dimension Fw is equal to 1/2 of the fin pitch Fp. A temperature of
intake air is raised when the intake air is compressed by a
turbocharger (not shown), and the compressed air flows into the
tank part 122 through the inlet pipe 123. Intake air is distributed
into the tubes 111 from the tank part 122. While intake air flows
inside of the tube 111, intake air is cooled by external cool air
through heat exchange. That is, heat of intake air is emitted to
the external cool air through the inner fin 114, the face 111a,
111b of the tube 111, and the outer fin 112. The cooled air is
gathered in the tank part 132, and flows out of the outlet pipe 133
so as to be supplied to the engine.
[0047] The air-cooled type intercooler 100A has a few number of the
tubes 111, and the tubes 111 are comparatively long. Therefore, if
intake air of the intercooler 100A is defined to have a pressure
loss .DELTA.Pg represented by a following Expression 1, the
pressure loss .DELTA.Pg becomes comparatively large.
.DELTA.Pg=4f(H/de)(.rho./2g)Vg.sup.2 (Expression 1)
[0048] f=coefficient of friction
[0049] H=longitudinal length of the tube
[0050] de=diameter of a circle corresponding to the tube
[0051] p=density of the supercharged air
[0052] g=gravitational acceleration
[0053] Vg=flowing velocity of intake air in the tube
[0054] The straight type inner fin 114 is arranged in the tube 111
in a manner that the flow resistance of intake air becomes
comparatively small. FIG. 9A illustrates a distribution of flowing
velocity of intake air in the tube 111 of the first embodiment, and
FIG. 9B shows a comparison example. The flowing velocity becomes
slower in order of a flowing velocity FR1, a flowing velocity FR2,
and a flowing velocity FR3, in FIG. 9A. The flowing velocity
becomes slower in order of a flowing velocity FR11, a flowing
velocity FR12, a flowing velocity FR13, a flowing velocity FR14,
and a flowing velocity FR 15, in FIG. 9B.
[0055] As shown in FIG. 9B representing the comparison example, a
passage is defined by a wall not having the protrusion 114c, 114d,
and a boundary layer of intake air flow is easily generated on the
second wall 114b and the tube inner face 111c corresponding to an
opening part of the inner fin 114. The boundary layer causes a
decrease in the heat radiating property.
[0056] In contrast, according to the first embodiment, the flow
resistance of intake air can be maintained low. Further, the
protrusion 114c, 114d is defined on the first wall 114a of the
inner fin 114, and the length ratio x/Fh and the protrusion ratio
y/Fw are set to have values within the hatched area of FIG. 8.
Therefore, as shown in FIG. 4B, intake air flowing through the tube
111 can be deflected toward the second wall 114b and the tube inner
face 111c opposite from with each other. The boundary layer formed
on the second wall 114b and the tube inner face 111c can be
disturbed, so that a thickness of the boundary layer can be
reduced. Heat transmitting efficiency can be improved on the intake
air side, and the heat radiating property can be raised.
[0057] As shown in FIG. 9A in contrast to FIG. 9B, a distribution
line of flowing velocity FR1, FR2, FR3 is varied in a direction
approaching the second wall 114b and the tube inner face 111c. It
is confirmed that the thickness of the boundary layer is
reduced.
[0058] A reason will be described below why the length ratio x/Fh
and the protrusion ratio y/Fw are set to have the values within a
predetermined range so as to obtain the above advantages. As shown
in FIG. 7, an optimal condition to improve a density ratio
(.rho./.rho.0) of supercharged air is acquired when the length
ratio x/Fh is variously changed between 0-1, using the protrusion
ratio y/Fw as a. parameter.
[0059] The density ratio (.rho./.rho.0) of supercharged air is a
ratio of a density (.rho.) of supercharged air of the first
embodiment to a density (.rho.0) of supercharged air of the
comparison example. The density (.rho.) of supercharged air
indicates a density of air flowing out of the intercooler 100A, and
is represented by a heat radiation performance and a pressure loss
of the intercooler 100A. The density (.rho.) of supercharged air is
computed by the following Expression 2.
.rho.=(Pg1-.DELTA.Pg)/{R(Tg1-Qg/GgCp)} (Expression 2)
[0060] Pg1=inlet-side pressure of intake air
[0061] .DELTA.Pg=pressure loss of intake air of the intercooler
[0062] R=gas constant
[0063] Tg1=inlet-side temperature of intake air
[0064] Qg=heat radiating amount
[0065] Gg=Mass flow rate of intake air
[0066] Cp=Specific heat of intake air
[0067] As the density (.rho.) of supercharged air is raised, the
pressure loss is reduced and the heat radiation property is made
better, in the intercooler 100A. Further, if the density ratio
(.rho./.rho.0) of supercharged air becomes equal to or higher than
100%, the properties of the intercooler 100A are better than those
of an intercooler of the comparison example.
[0068] In FIG. 7, when the length ratio x/Fh is increased from 0 to
1.0 with a parameter of the protrusion ratio y/Fw, the density
ratio .rho./.rho.0 of supercharged air becomes equal to or higher
than 100%, and has a maximum value.
[0069] Specifically, the density ratio of .rho./.rho.0 of
supercharged air becomes equal to or higher than 100% and has the
maximum value when the protrusion ratio y/Fw has a value of 0.05
and the length ratio x/Fh is in a range of 0-0.89.
[0070] The density ratio .rho./.rho.0 of supercharged air becomes
equal to or higher than 100% and has the maximum value when the
protrusion ratio y/Fw has a value of 0.1 and when the length ratio
x/Fh is in a range of 0-1.0.
[0071] The density ratio .rho./.rho.0 of supercharged air becomes
equal to or higher than 100% and has the maximum value when the
protrusion ratio y/Fw has a value of 0.15 and when the length ratio
x/Fh is in a range of 0-0.87.
[0072] The density ratio .rho./.rho.0 of supercharged air becomes
equal to or higher than 100% and has the maximum value when the
protrusion ratio y/Fw has a value of 0.2 and when the length ratio
x/Fh is in a range of 0-0.77.
[0073] The density ratio .rho./.rho.0 of supercharged air becomes
equal to or higher than 100% and has the maximum value when the
protrusion ratio y/Fw has a value of 0.25 and when the length ratio
x/Fh is in a range of 0-0.64.
[0074] That is, with respect to each protrusion ratio y/Fw, if the
length ratio x/Fh is set in the above-mentioned predetermined
range, the density p of supercharged air can be raised compared
with the comparison example. The pressure loss is reduced, and the
heat radiation property of the intercooler 100A can be raised.
[0075] As shown in FIG. 8, when the length ratio x/Fh is applied to
a lateral axis of a two-axis coordinate, and when the protrusion
ratio y/Fw is applied to a vertical axis of the two-axis
coordinate, the length ratio x/Fh and the protrusion ratio y/Fw are
set to have values in an area surrounded by the vertical axis and
lines connecting a point (x/Fh, y/Fw=0, 0), a point (x/Fh,
y/Fw=0.89, 0.05), a point (x/Fh, y/Fw=1.0, 0.1), a point (x/Fh,
y/Fw=0.87, 0.15), a point (x/Fh, y/Fw=0.77, 0.2), a point (x/Fh,
y/Fw=0.64, 0.25), and a point (x/Fh, y/Fw=0, 0.4) in this order. In
this case, the combination of the protrusion ratio y/Fw and the
length ratio x/Fh causes the density ratio .rho./.rho.0 of
supercharged air to become more than or equal to 100%. The maximum
side value of the length ratio x/Fh of FIG. 7 to make the density
ratio 100% or more is set as an upper limit of the length ratio
x/Fh with respect to each point.
[0076] Especially, in FIG. 7, when the protrusion ratio y/Fw is set
as 0.1, the density ratio .rho./.rho.0 of supercharged air becomes
the largest. At this time, the length ratio x/Fh may be preferably
set in a range between 0.43 and 0.87.
[0077] The protrusion 114c, 114d protruding on a first side in the
major direction is produced by pressing the first wall 114a from a
second side toward the first side.
[0078] Therefore, the protrusion 114c, 114d can be easily formed by
a roller processing or a pressing processing when the inner fin 114
is produced.
Second Embodiment
[0079] As shown in FIGS. 10A-10D, an inner fin 114 has a protrusion
114e, 114f. Shape, number and location of the protrusion 114e, 114f
are different from those of the protrusion 114c, 114d of the first
embodiment.
[0080] As shown in FIG. 10A, the protrusion 114e has a circle shape
while the protrusion 114c, 114d has the ellipse shape. The
protrusion 114e may be formed by dimpling. As shown in FIG. 10B, a
plurality of the protrusions 114e may be arranged in the connecting
direction.
[0081] As shown in FIG. 10C, the protrusion 114f has a triangle
shape while the protrusion 114c, 114d has the ellipse shape. A
first angle of the protrusion 114f having the triangle shape is
located on an upstream side in the flowing direction of intake air
A second angle and a third angle are located on a downstream side
in the flowing direction of intake air, and arranged in the
connecting direction. Intake air is effectively deflected toward
the second wall 114b and the tube inner face 111c opposing with
each other in the tube thickness direction.
[0082] As shown in FIG. 10D, three of the circle protrusions 114e
are arranged to define an imaginary triangle, and the protrusions
114e are respectively located at three angle portions of the
imaginary triangle. Locations of the angle portions with respect to
the flowing direction of intake air are the same as FIG. 10C.
[0083] According to the second embodiment, similar advantages can
be obtained as the first embodiment, if the length ratio x/Fh and
the protrusion ratio y/Fw are set to have values within the hatched
area of FIG. 8. In the case of FIGS. 10B and 10D, the extending
dimension x of the protrusions 114e is defined to be entire length
of the protrusions 114e in the connecting direction.
Third Embodiment
[0084] As shown in FIG. 11, an inner fin 114 has a protrusion 114g.
A location of the protrusion 114g is different from that of the
protrusion 114c, 114d of the first embodiment.
[0085] The protrusion 114g is defined in the second wall 114b by
being pressed from outside to be connected to the tube inner face
111c. The protrusion 114g protrudes toward a center side of the
tube 111. That is, the protrusion 114g protrudes from an inner face
of the second wall 114b toward an open side of the inner fin 114
having the waveform. For example, the protrusion 114g has a circle
shape.
[0086] According to the third embodiment, the flow resistance of
intake air can be maintained low. Further, the protrusion 114g is
defined on the second wall 114b of the inner fin 114, so that
intake air flowing through the tube 111 adjacent to the second wall
114b can be disturbed by the protrusion 114g. The boundary layer
formed on the second wall 114b can be disturbed, so that a
thickness of the boundary layer can be reduced. Heat transmitting
efficiency can be improved on the intake air side, and the heat
radiating property can be raised.
Other Embodiment
[0087] The above embodiments may be applied to an intercooler 100B
shown in FIG. 12, which has a comparatively large number of tubes
111, and the tubes 111 are comparatively short, compared with the
intercooler 100A.
[0088] The protrusion 114c, 114d, 114e, 114f, 114g is not limited
to protrude on a first side in the major direction or the
connecting direction by pressing the first wall 114a or the second
wall 114b from a second side opposite from the first side in the
major direction or the connecting direction. Alternatively, the
protrusion 114c, 114d, 114e, 114f, 114g may be formed by cutting
and bending the wall 114a, 114b. In this case, the cut and
separated part is located on a downstream side in the flowing
direction of intake air, and the bent and connected part is located
on an upstream side in the flowing direction of intake air.
[0089] Each component of the intercooler 100A, 100B is not limited
to be made of aluminum or aluminum alloy, but may be made of
copper-base material or iron base material. The header tank 120,
130 is not limited to be made of aluminum-base, copper-base or
iron-base material, but may be made of resin material.
[0090] The intercooler 100A, 100B is not limited to the air-cooled
type one using air as external fluid to cool the intake air, but
may be a water-cooled type one using cooling water as the external
fluid.
[0091] Such changes and modifications are to be understood as being
within the scope of the present invention as defined by the
appended claims.
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