U.S. patent application number 13/131187 was filed with the patent office on 2011-09-29 for combined heat exchanger.
This patent application is currently assigned to Calsonic Kansei Corporation. Invention is credited to Mitsuru Iwasaki, Yuichi Meguriya.
Application Number | 20110232868 13/131187 |
Document ID | / |
Family ID | 42225683 |
Filed Date | 2011-09-29 |
United States Patent
Application |
20110232868 |
Kind Code |
A1 |
Iwasaki; Mitsuru ; et
al. |
September 29, 2011 |
COMBINED HEAT EXCHANGER
Abstract
A combined heat-exchanger includes a first air-cooled
heat-exchanger for cooling coolant for a heat generator other than
an internal combustion engine in an automobile and a second
air-cooled heat-exchanger for cooling refrigerant for
air-conditioning. The first air-cooled heat-exchanger includes an
upstream tank into which the coolant flows, a downstream tank form
which the refrigerant flows out, flow channel members that
communicate the upstream tank with the downstream tank, heat
release fins that are alternately stacked with the flow channel
members, and a water-cooled heat-exchanger for cooling the
refrigerant. The water-cooled heat-exchanger is disposed within the
downstream tank, and includes an inlet port to which the
refrigerant flows at its upper portion and an outlet port from
which the refrigerant flows out at its lower portion. According to
the heat-exchanger, staying of oil mixed in the refrigerant can be
prevented, heat exchange efficiency can improve and downsizing can
be achieved.
Inventors: |
Iwasaki; Mitsuru; (Kanagawa,
JP) ; Meguriya; Yuichi; (Tochigi, JP) |
Assignee: |
Calsonic Kansei Corporation
|
Family ID: |
42225683 |
Appl. No.: |
13/131187 |
Filed: |
November 24, 2009 |
PCT Filed: |
November 24, 2009 |
PCT NO: |
PCT/JP2009/069779 |
371 Date: |
May 25, 2011 |
Current U.S.
Class: |
165/104.13 |
Current CPC
Class: |
F28D 1/0452 20130101;
F28F 9/0234 20130101 |
Class at
Publication: |
165/104.13 |
International
Class: |
F28D 15/00 20060101
F28D015/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 26, 2008 |
JP |
2008-301312 |
Claims
1. A combined heat exchanger used for a cooling system that
includes a first air-cooled heat exchanger for cooling coolant for
a heat generator other than an internal combustion engine in an
automobile and a second air-cooled heat exchanger for cooling
refrigerant for air-conditioning, wherein the first air-cooled heat
exchanger includes an upstream tank into which the coolant flows, a
downstream tank form which the refrigerant flows out, a plurality
of flow channel members that communicate the upstream tank with the
downstream tank, a plurality of heat release fins that are
alternately stacked with the flow channel members, and a
water-cooled heat exchanger for cooling the refrigerant; the
water-cooled heat exchanger is disposed within the upstream tank or
the downstream tank, and includes an inlet port to which the
refrigerant flows at an upper portion thereof and an outlet port
from which the refrigerant flows out at a lower portion thereof;
and the second air-cooled heat exchanger is disposed below the
first air-cooled heat exchanger and the refrigerant that flown out
from the water-cooled heat exchanger flows into the second
air-cooled heat exchanger.
2. The combined heat exchanger according to claim 1, wherein the
water-cooled heat exchanger is disposed within the downstream
tank.
3. The combined heat exchanger according to claim 1, wherein the
first air-cooled heat exchanger and the second air-cooled heat
exchanger are disposed adjacent to each other on a plane
perpendicular to a flow of cooling air therethrough.
4. The combined heat exchanger according to claim 1, wherein the
water-cooled heat exchanger is configured by stacking a plurality
of refrigerant flow-passage units as flow passage of the
refrigerant with gaps therebetween, the coolant flowing through the
gaps, and each of the refrigerant flow-passage units is oriented
vertically.
5. The combined heat exchanger according to claim 4, wherein a
lower end of each of the refrigerant flow-passage units is formed
almost circularly rounded.
6. The combined heat exchanger according to claim 4, wherein each
of the refrigerant flow-passage units includes a shell tube on
which an inflow port communicating with the inlet port and an
outflow port communicating with the outlet port are formed near
both ends thereof in a flow direction of the refrigerant, and an
inner fin that is fixed in the shell tube and on which an inflow
hole corresponding to the inflow port, an outflow hole
corresponding to the outflow port and a plurality of grooves along
a flow of the refrigerant are formed; and a slit extended from the
inflow hole and a slit extended from the outflow hole are formed on
the inner fin.
7. The combined heat exchanger according to claim 4, wherein each
of the refrigerant flow-passage units includes a shell tube on
which an inflow port communicating with the inlet port and an
outflow port communicating with the outlet port are formed near
both ends thereof in a flow direction of the refrigerant, and an
inner fin that is fixed in the shell tube and on which an inflow
hole corresponding to the inflow port, an outflow hole
corresponding to the outflow port and a plurality of grooves along
a flow of the refrigerant are formed; and a notch along an edge on
a side of the inflow hole and a notch along an edge on a side of
the outflow hole are formed on the inner fin.
Description
TECHNICAL FIELD
[0001] The present invention relates to a combined heat exchanger
that uses plural types of refrigerants (e.g. engine coolant and
air-conditioning refrigerant) in a cooling cycle for an
automobile.
BACKGROUND ART
[0002] A heat exchanger is disclosed in Japanese Patent Application
Laid-Open No. 2006-162176 [Patent Document 1].
[0003] This heat exchanger is used in an air conditioner for a
vehicle, and a heat exchanger for air-conditioning refrigerant is
implemented in a tank (header) of an air-cooled heat exchanger for
engine coolant to cool air-conditioning refrigerant by air-cooled
coolant. In this heat exchanger for air-conditioning refrigerant,
the refrigerant is flown into from its lower side and frown out
from its upper side.
[0004] Oil for a compressor is subject to be mixed in
air-conditioning refrigerant, and the refrigerant circulates in a
system together with the mixed oil. Some of the mixed oil separates
from the refrigerant.
SUMMARY OF INVENTION
[0005] In the heat exchanger in the above Patent Document 1, the
refrigerant flows from its lower side to its upper side, so that it
may happen that the oil stays at a lower portion of the heat
exchanger. If the oil stays, there are concerns of degradation of
heat-exchange efficiency, or degradation of performance and
reliability of a cooling system due to insufficient lubrication in
the compressor.
[0006] In addition, a recent vehicle has heat generators such as an
internal combustion engine, an intercooler for supercharging, an
air conditioner and an electric motor for a hybrid electric
vehicle. Therefore, a compact and effective heat exchanger
(combined heat exchanger) is desired to cool these heat generators
(to exhaust heat of the heat generators).
[0007] An object of the present invention is to provide a combined
heat exchanger that can prevent oil mixed in refrigerant from
staying, and thereby it is superior in heat exchange effectiveness
and compact.
[0008] An aspect of the present invention provides a combined heat
exchanger used for a cooling system that includes a first
air-cooled heat exchanger for cooling coolant for a heat generator
other than an internal combustion engine in an automobile and a
second air-cooled heat exchanger for cooling refrigerant for
air-conditioning, wherein the first air-cooled heat exchanger
includes an upstream tank into which the coolant flows, a
downstream tank form which the refrigerant flows out, flow channel
members that communicate the upstream tank with the downstream
tank, heat release fins that are alternately stacked with the flow
channel members, and a water-cooled heat exchanger for cooling the
refrigerant; the water-cooled heat exchanger is disposed within the
upstream tank or the downstream tank, and includes an inlet port to
which the refrigerant flows at an upper portion thereof and an
outlet port from which the refrigerant flows out at a lower portion
thereof; and the second air-cooled heat exchanger is disposed below
the first air-cooled heat exchanger and the refrigerant that flown
out from the water-cooled heat exchanger flows into the second
air-cooled heat exchanger.
[0009] According to the above aspect, the refrigerant is flown into
the water-cooled heat exchanger from the inlet port at the upper
portion, and flown out from the outlet port at the lower portion.
Therefore, oil is prevented from staying at the lower portion, and
thereby heat exchange efficiency improves. In addition,
insufficient lubrication in a compressor, and degradation of
performance and reliability of the cooling system due to the
oil-staying are prevented.
[0010] In addition, since the refrigerant flown out from the
water-cooled heat exchanger smoothly flows down to the second
air-cooled heat exchanger disposed below the first air-cooled heat
exchanger (the water-cooled heat exchanger), restraining effect of
oil-staying further improves in the water-cooled heat exchanger and
the second air-cooled heat exchanger.
[0011] Especially, in a device in which flow-speed of the
refrigerant reduces due to volume decrease along with its
condensation, such as a condenser and the water-cooled heat
exchanger in a cooling system, the above-mentioned restraining
effect of oil-staying is quite noticeable.
[0012] Here, it is preferable that the water-cooled heat exchanger
is disposed within the downstream tank. According to this, since
the water-cooled heat exchanger is disposed within the downstream
tank within which the cooled coolant circulates, high heat exchange
efficiency can be brought.
[0013] Here, it is preferable that the first air-cooled heat
exchanger and the second air-cooled heat exchanger are disposed
adjacent to each other on a plane perpendicular to a flow of
cooling air therethrough.
[0014] According to this, since the first air-cooled heat exchanger
and the second air-cooled heat exchanger are disposed adjacent to
each other on the plane perpendicular to the flow of cooling air,
the combined heat exchanger can be configured extremely compact,
and thereby exerts superior performance in its installation to a
vehicle. As a result, the combined heat exchanger is used in a
cooling system in a vehicle, and thereby can effectively cool heat
generators such as an engine, an intercooler for a super-charging
unit, an air-conditioner and a drive motor in a hybrid electric
vehicle.
[0015] Here, it is preferable that the water-cooled heat exchanger
is configured by stacking a plurality of refrigerant flow-passage
units as flow passage of the refrigerant with gaps therebetween,
the coolant flowing through the gaps, and each of the refrigerant
flow-passage units is oriented vertically.
[0016] According to this, since the water-cooled heat exchanger is
disposed vertically, the refrigerant flows down almost vertically
in the refrigerant flow-passage units. As a result, the restraining
effect of oil-staying further improves.
[0017] Further, it is preferable that a lower end of each of the
refrigerant flow-passage units is formed almost circularly
rounded.
[0018] According to this, since the lower end of each of the
refrigerant flow-passage units is formed almost circularly rounded,
oil flows smoothly and thereby partial staying is restrained. As a
result, the restraining effect of oil-staying further improves.
[0019] Note that, if an upper end of each of the refrigerant
flow-passage units is formed almost circularly rounded, the
refrigerant spreads in a width direction of each of the inner fins
along with this shape. Therefore, heat-exchange efficiency between
the refrigerant and the coolant further improves.
[0020] Furthermore, it is preferable that each of the refrigerant
flow-passage units includes a shell tube on which an inflow port
communicating with the inlet port and an outflow port communicating
with the outlet port are formed near both ends thereof in a flow
direction of the refrigerant, and an inner fin that is fixed in the
shell tube and on which an inflow hole corresponding to the inflow
port, an outflow hole corresponding to the outflow port and a
plurality of grooves along a flow of the refrigerant are formed;
and a slit extended from the inflow hole and a slit extended from
the outflow hole are formed on the inner fin.
[0021] According to this, the refrigerant is spread and then
collected in a direction perpendicular to its flow due to the slits
extended from the inflow hole and the outflow hole. Therefore, the
heat exchange efficiency and the restraining effect of oil-staying
improve. In addition, since the inner fin is fixed within the shell
tube, anti-pressure strength of the shell tube is kept high.
[0022] Alternatively, it is preferable that each of the refrigerant
flow-passage units includes a shell tube on which an inflow port
communicating with the inlet port and an outflow port communicating
with the outlet port are formed near both ends thereof in a flow
direction of the refrigerant, and an inner fin that is fixed in the
shell tube and on which an inflow hole corresponding to the inflow
port, an outflow hole corresponding to the outflow port and a
plurality of grooves along a flow of the refrigerant are formed;
and a notch along an edge on a side of the inflow hole and a notch
along an edge on a side of the outflow hole are formed on the inner
fin.
[0023] According to this, the refrigerant is spread and then
collected in a direction perpendicular to its flow due to the
notches formed along the edge on the side of the inflow hole and
the edge on the side of the outflow hole on the inner fin.
Therefore, the heat exchange efficiency and the restraining effect
of oil-staying improve. In addition, since the inner fin is fixed
within the shell tube, anti-pressure strength of the shell tube is
kept high.
BRIEF DESCRIPTION OF DRAWINGS
[0024] [FIG. 1] is a schematic drawing showing a part of a cooling
system to which a heat exchanger of a first embodiment according to
the present invention is applied.
[0025] [FIG. 2] is a perspective view showing a combined state of a
sub-radiator (for others than an engine), a radiator (for the
engine) and a condenser for air-conditioning.
[0026] [FIG. 3] is a perspective view of the sub-radiator.
[0027] [FIG. 4] is a cross-sectional view showing a water-cooled
heat exchanger implemented in a downstream tank of the
sub-radiator.
[0028] [FIG. 5] is a side view of the water-cooled heat
exchanger.
[0029] [FIG. 6] is a perspective view of the water-cooled heat
exchanger.
[0030] [FIG. 7] is an exploded perspective view of the water-cooled
heat exchanger.
[0031] [FIG. 8] (a) is a plan view of an inner fin used in a heat
exchanger of a second embodiment according to the present
invention, and (b) is a cross-sectional view taken along a line
VIIIB-VIIIB in FIG. 8(a).
[0032] [FIG. 9] (a) is a plan view of an inner fin used in a heat
exchanger of a third embodiment according to the present invention,
and (b) is a cross-sectional view taken along a line IXB-IXB in
FIG. 9(a).
DESCRIPTION OF EMBODIMENT
First Embodiment
[0033] A combined heat exchanger 1 according to a first embodiment
will be explained with reference to FIGS. 1 to 7. As shown in FIG.
1, the combined heat exchanger 1 is used in a cooling system 9 in a
hybrid electric vehicle that has an engine (internal combustion
engine: not shown) and an electric motor 3 as sources of a driving
force.
[0034] The combined heat exchanger 1 is used in the cooling system
9 that includes a sub-radiator 5 (first air-cooled heat exchanger)
and a condenser 7 (second air-cooled heat exchanger) as shown in
FIG. 1. The sub-radiator 5 cools coolant for the drive motor 3 and
control devices (heat generators other than the engine) such as an
inverter or a converter. On the other hand, the condenser 7 cools
air-conditioning refrigerant.
[0035] The sub-radiator 5 includes an upstream tank 11, a
downstream tank 13, flat tubes 15 (flow channel members), heat
release fins 17, and a water-cooled heat exchanger 19 as shown in
FIGS. 1 to 3. The coolant flows into the upstream tank 11 and then
flows out from the downstream tank 13. The upstream tank 11 is
communicated with the downstream tank 13 by the flat tubes 15. The
heat release fins 17 are alternately stacked with the flat tubes
15. The water-cooled heat exchanger 19 cools the air-conditioning
refrigerant (as explained above, the refrigerant is also cooled by
the condenser 7).
[0036] As shown in FIGS. 4 and 5, the water-cooled heat exchanger
19 is disposed within the downstream tank 13. The condenser 7 is
disposed below the sub-radiator 5 as shown in FIG. 2. The
refrigerant flows into the water-cooled heat exchanger 19 from an
upper side of the water-cooled heat exchanger 19, and then flows
out from a lower side of the water-cooled heat exchanger 19, as
shown in FIG. 5. The refrigerant that has flown out from the
water-cooled heat exchanger 19 flows down to the condenser 7.
[0037] In addition, as shown in FIG. 2, the sub-radiator 5 and the
condenser 7 are disposed on a plane that is almost perpendicular to
a flow of cooling air (outside air inflowing from a front grill
during a vehicle running) for cooling them. The sub-radiator 5 and
the condenser 7 are disposed adjacent to each other.
[0038] In addition, as shown in FIG. 5, the water-cooled heat
exchanger 19 is configured by stacking plural shell tubes
(refrigerant flow-passage units) 21 as flow passages of the
refrigerant with gaps 25 therebetween. The coolant in the
downstream tank 13 flows through the gaps 25. Each of the shell
tubes 21 is oriented vertically so as to flow the refrigerant in a
vertical direction (gravity direction). Upper and lower end (at
least a lower end) of each of the shell tubes are formed almost
circularly rounded.
[0039] As shown in FIG. 3, reinforcements 26 (reinforcing members)
are attached to upper and lower end of the stacked flat tubes 15 of
the sub-radiator 5, respectively. The flat tubes 15 are subject to
an adequate load with sandwiched between the reinforcements 26, and
their both ends are inserted into the tanks 11 and 13.
[0040] In addition, as shown in FIG. 2, the sub-radiator 5 and the
condenser 7 are disposed vertically. Then, a radiator 27 for the
engine is disposed at a downstream of cooling air passing through
the sub-radiator 5 and the condenser 7. The engine coolant is
cooled by the cooling air in the radiator 27.
[0041] The water-cooled heat exchanger 19 is configured by the
shell tubes (refrigerant flow-passage units) 21, inner fins
(refrigerant flow-passage units) 29, ring-shaped patches 31, and
plate-shaped end patches 33, as shown in FIGS. 5 and 7. In
addition, a shell 21a that composes each of the shell tubes 21
includes a circumferential edge 35, beads (bulges) 39, and an
inflow port 43 and an outflow port 47 that are provided upper and
lower sides (near is both ends in a flow direction of the
refrigerant), as shown in FIGS. 4 and 6. Similarly, another shell
21b includes a circumferential edge 37, beads 41, an inflow port
45, and an outflow port 49. The circumferential edge 35 of the
shell 21a is engaged with the circumferential edge 37 of the shell
21b. The inflow port 43 of the shell 21a is engaged with the inflow
port 45 of the facing shell 21b. The outflow port 47 of the shell
21a is engaged with the outflow port 49 of the facing shell 21b.
The inner fin 29 includes an inflow hole 51 corresponding to the
inflow ports 43 and 45, an outflow hole 53 corresponding to the
outflow ports 47 and 49, and multiple grooves 55 along the flow
direction of the refrigerant. The grooves 55 are formed by
processing the inner fin 29 corrugated.
[0042] A pair of the shell 21a and 21b is engaged with each other
at their circumferential edges 35 and 37 with interposing the inner
fin 29 therebetween, so that an assembly (a unit) of the shell tube
21 is constructed. The plural shell tubes 21 are sequentially
connected with each other at their inflow ports 43 and 45 and their
outflow ports 47 and 49 with interposing the patches 31
therebetween. Here, the beads 39 and 41 on the adjacent shell tubes
21 are contacted with each other. A constant proper load applies in
a stacking direction of the shell tubes 21. In addition, the inflow
port 45 and the outflow port 49 of the outermost shell 21b are
sealed by the end patches 33. Each clearance of the gaps 25 is kept
proper by the patches 31 and the beads 39 and 41. The water-cooled
heat exchanger 19 is constructed by brazing these above-mentioned
elements with each other. The inner fin 29 is brazed with the
shells 21a and 21b at its top edges of the corrugated shape. In
addition, as shown in FIGS. 2, 5 and 6, the inflow port 43 of the
innermost shell 21a is connected with a compressor in the cooling
system 9 via an inlet port 57. Similarly, the outflow port 47 of
the innermost shell 21a is connected with the condenser 7 in the
cooling system 9 via an outlet port 59.
[0043] In the cooling system 9, the coolant for the drive motor 3
and such is circulated by a pump 61, and flown into the upstream
tank 11 as shown in FIGS. 2 and 3. The coolant is cooled by cooling
air via the heat release fins 17 while flowing through the flat
tubes 15, and then flown out from the downstream tank 13 to cool
the drive motor 3 and such.
[0044] In addition, the air-conditioning refrigerant in a
high-temperature and high-temperature gas state that has been
compressed by the compressor is flown into the shell tubes 21 of
the water-cooled heat exchanger 19 from the inflow port 43 and 45,
as shown in FIG. 5. The refrigerant is cooled by the coolant
flowing in the downstream tank 13 while flowing down along the
grooves 55 of the inner fin 19. The cooled refrigerant becomes gas
state where its superheat degree reduces or gas-fluid mixed state
where it is partially saturated, and then is flown out from the
outflow port 47 and 49. Further, the refrigerant flows down to the
condenser 7 and is condensed. The refrigerant flown out from the
condenser 7 is decompressed by a pressure reduction valve (not
shown). The decompressed refrigerant is heat-changed in an
evaporator (not shown). The refrigerant flown out from the
evaporator is compressed by the compressor. Then, this cycle is
repeated.
[0045] Next, effects according to the combined heat exchanger 1
will be explained.
[0046] Since the water-cooled heat exchanger 19 is configured so as
to flow the refrigerant from its upper side to its lower side and
then flow out it therefrom, it is restrained that lubricating oil
for the compressor that is mixed in the refrigerant stays at the
lower side of the water-cooled heat exchanger 19. Further, since
the lower end of the shell tube 21 is formed almost circularly
rounded, the restraining effect of oil-staying improves. As a
result, degradation of heat-exchange efficiency due to oil-staying,
and degradation of performance and reliability of the cooling
system 9 due to insufficient lubrication in the compressor are
restrained.
[0047] In addition, since the water-cooled heat exchanger 19 is
disposed in the downstream tank 13 for the coolant that has been
cooled by cooling air, high heat-exchange efficiency can be
brought.
[0048] In addition, since the water-cooled heat exchanger 19 is
disposed vertically, the refrigerant flows down almost vertically.
As a result, the restraining effect of oil-staying further
improves.
[0049] In addition, since the upper end of the shell tube 21 is
also formed almost circularly rounded, the refrigerant spreads in a
width direction of the inner fin 29 along with this shape, as shown
by arrows 63 in FIG. 4. As a result, heat-exchange efficiency
between the refrigerant and the coolant further improves.
[0050] Especially, in the water-cooled heat exchanger 19 and the
condenser 7 in which flow-speed of the refrigerant reduces due to
volume decrease along with its condensation, the above-mentioned
restraining effect of oil-staying is quite noticeable.
[0051] In addition, since the condenser 7 is disposed adjacent
below the sub-radiator 5 on the plane perpendicular to a flow of
cooling air, the combined heat exchanger 1 is configured extremely
compact, and thereby exerts superior performance in its
installation to a vehicle. As a result, the combined heat exchanger
1 is used in the cooling system 9 in a vehicle, and thereby can
effectively cool heat generators such as the engine, the
air-conditioner and the drive motor 3.
Second Embodiment
[0052] A combined heat exchanger according to a second embodiment
will be explained with reference to FIGS. 8(a) and 8(b).
[0053] In the combined heat exchanger according to the present
embodiment, an inner fin (refrigerant-passage unit) 101 fixed
within the shell tube (refrigerant-passage unit) 21 is extended to
circularly curved portions located at its both ends in the flow
direction of the refrigerant. In addition, a pair of slits 103
extended from the inflow hole 51 is formed on both sides of the
inflow hole 51. Similarly, a pair of slits 105 extended from the
outflow hole 53 is formed on both sides of the outflow hole 53. The
inner fin 101 is brazed with the shell tube 21 at its top edges of
the corrugated shape and at its both ends in the flow direction.
Therefore, anti-pressure strength of tube is ensured to its both
ends in the flow direction.
[0054] The slits 103 and 105 are disposed to extend over some of
the grooves 55. The refrigerant is spread (from the inflow hole 51:
the slits 103) in an almost perpendicular direction (in the width
direction) to its flow direction due to the slits 103 and 105, and
then collected (to the slits 105: the outflow hole 53). Since the
refrigerant flows in a full-width of the shell tube 21 due to slits
103 and 105, a contact area between the refrigerant and the coolant
is expanded and thereby heat-exchange efficiency improves. In
addition, since the slits 105 are inclined so as to lower their own
sides communicating with the outflow hole 53, oil in the
refrigerant is surely introduced into the outflow hole 53.
[0055] In addition, an outer diameter r of the patch 31 is smaller
than each outer diameter R of both ends 157 and 159 (FIG. 4) of the
shell tube 21. In addition, the slits 103 and 105 extend outward
from an outer circumference of the patch 31. By attaching the
patches 31 onto circumferences of the adjacent inflow ports 43 and
45 and the adjacent outflow ports 47 and 49, strength degradation
of the inner fin 29 due to slits 103 and 105 is reinforced and
thereby durability is further improved.
[0056] In addition, although both the inflow hole 51 and the
outflow hole 53 are disposed at a center on the inner fin 101 in
its width direction, they may be disposed with offset in the width
direction. In this case, the flow of the refrigerant can be further
spread in the width direction. As a result, heat-exchange
efficiency can further improve.
Third Embodiment
[0057] A combined heat exchanger according to a third embodiment
will be explained with reference to FIGS. 9(a) and 9(b).
[0058] In the combined heat exchanger according to the present
embodiment, notches 153 and 155 are formed on the inner fin
(refrigerant-passage unit) 151. The upper notch 153 is provided in
the width direction along the end 157 (FIG. 4) of the shell tube 21
on a side of the inflow ports 43 and 45. Similarly, the lower notch
155 is provided in the width direction along the end 159 (FIG. 4)
of the shell tube 21 on a side of the outflow ports 47 and 49.
[0059] In the combined heat exchanger according to the present
embodiment, the notches 153 and 155 are disposed to extend all of
the grooves 55. The refrigerant is spread (from the inflow hole 51:
the notch 153) in an almost perpendicular direction (in the width
direction) to its flow direction due to the notches 153 and 155,
and then collected (to the notch 155: the outflow hole 53). Since
the refrigerant flows in a full-width of the shell tube 21 due to
notches 153 and 155, a contact area between the refrigerant and the
coolant is expanded and thereby heat-exchange efficiency
improves.
[0060] In addition, the inflow hole 51 and the outflow hole 53 may
be disposed with offset in the width direction also on the inner
fin 151. In this case, the flow of the refrigerant can be further
spread in the width direction. As a result, heat-exchange
efficiency can further improve.
[0061] Note that the present invention is not construed with
limited only to the above embodiments and can be variously modified
within a technical scope of the present invention.
* * * * *