U.S. patent application number 16/904110 was filed with the patent office on 2020-10-08 for cooling circuit and oil cooler.
The applicant listed for this patent is DENSO CORPORATION. Invention is credited to Masashi MIYAGAWA.
Application Number | 20200318529 16/904110 |
Document ID | / |
Family ID | 1000004931948 |
Filed Date | 2020-10-08 |
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United States Patent
Application |
20200318529 |
Kind Code |
A1 |
MIYAGAWA; Masashi |
October 8, 2020 |
COOLING CIRCUIT AND OIL COOLER
Abstract
A cooling circuit includes a first coolant passage in which a
coolant flows, a second coolant passage in which the coolant flows,
a thermostat, and an oil cooler configured to heat or cool oil. The
thermostat interrupts a flow of the coolant flowing through the
first coolant passage when a temperature of the coolant flowing
into the thermostat is lower than a predetermined temperature, and
allows the coolant to flow through the first coolant passage when
the temperature of the coolant is at or above a predetermined
temperature. The oil cooler includes a first coolant inflow port, a
first coolant outflow port, a second coolant inflow port, and a
second coolant outflow port. The oil cooler heats or cools the oil
by heat exchange between the coolant flowing from the first coolant
inflow port or/and the second coolant inflow port and the oil.
Inventors: |
MIYAGAWA; Masashi;
(Kariya-city, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DENSO CORPORATION |
Kariya-city |
|
JP |
|
|
Family ID: |
1000004931948 |
Appl. No.: |
16/904110 |
Filed: |
June 17, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/JP2018/043173 |
Nov 22, 2018 |
|
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|
16904110 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F01P 11/08 20130101;
F28D 9/0093 20130101; F01P 7/16 20130101 |
International
Class: |
F01P 7/16 20060101
F01P007/16; F28D 9/00 20060101 F28D009/00; F01P 11/08 20060101
F01P011/08 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 22, 2017 |
JP |
2017-245714 |
Claims
1. A cooling circuit comprising: a first coolant passage in which a
coolant flows; a second coolant passage in which the coolant flows;
a thermostat configured to interrupt a flow of the coolant flowing
through the first coolant passage when a temperature of coolant
flowing into the thermostat is lower than a predetermined
temperature, and to allow the coolant to flow through the first
coolant passage when the temperature of the coolant is at or above
a predetermined temperature; and an oil cooler configured to heat
or cool oil, wherein the oil cooler includes: a first coolant
inflow port into which the coolant flowing in the first coolant
passage flows; a second coolant inflow port into which the coolant
flowing in the second coolant passage flows; an inner passage
provided therein to communicate with the first coolant inflow port
and the second coolant inflow port; a first coolant outflow port,
provided to communicate with the inner passage, through which the
coolant having passed through the inner passage flows out of the
oil cooler and flows into the first coolant passage; and a second
coolant outflow port, provided to communicate with the inner
passage, through which the coolant having passed through the inner
passage flows into the second coolant passage, the inner passage of
the oil cooler is configured to perform heat exchange between the
coolant flowing therein and the oil, and the first coolant passage
and the second coolant passage are coupled to the oil cooler, to
cause the coolant in the second coolant passage flows into the
inner passage only through the second coolant inflow port when the
thermostat interrupts the flow of the coolant flowing through the
first coolant passage, and to cause the coolant in the first
coolant passage and the second coolant passage flows into the inner
passage through both of the first coolant inflow port and the
second coolant inflow port when the thermostat allows the flow of
the coolant flowing through the first coolant passage.
2. The cooling circuit according to claim 1 further comprising: a
bypass passage that couples the first coolant inflow port to the
first coolant passage; and a flow regulator provided in the bypass
passage and configured to regulate a flow of the coolant flowing
from the first coolant inflow port toward the first coolant
passage.
3. The cooling circuit according to claim 2, wherein the flow
regulator is a check valve.
4. The cooling circuit according to claim 1, wherein the oil cooler
is configured to have a flow direction of the coolant flowing from
the first coolant inflow port to the first coolant outflow port,
which intersects with a flow direction of the oil flowing in the
oil cooler.
5. The cooling circuit according to claim 1, wherein the oil is
used for an transmission in a vehicle.
6. The cooling circuit according to claim 1, wherein the oil is
used for a power machine in a vehicle.
7. An oil cooler configured by a plurality of plates laminated to
define an oil passage through which an oil flows and a coolant
passage through which coolant flows, the oil passage and the
coolant passage being arranged alternatively, the oil cooler
comprising a plurality of coolant plates defining the coolant
passage, each of the coolant plate includes: an inner passage in
which the coolant flows; a first coolant inflow passage through
which the coolant flows into the inner passage; a second coolant
inflow passage through which the coolant flows into the inner
passage; a first coolant outflow passage through which the coolant
in the inner passage flows out; and a second coolant outflow
passage through which the coolant in the inner passage flows out,
the inner passage is configured to communicate with both the first
coolant inflow passage and the second coolant inflow passage and to
communicate with the first coolant outflow passage and the second
coolant outflow passage, to cause the coolant flows into the inner
passage only through the second coolant inflow port when a flow of
the coolant flowing into the first coolant inflow passage is
closed, and to cause the coolant flows into the inner passage
through both of the first coolant inflow port and the second
coolant inflow port when the coolant flows into the first coolant
inflow passage and the second coolant inflow passage.
8. The oil cooler according to claim 7, wherein the coolant plate
further includes a flow resistance applying part configured to
cause a flow resistance of the coolant flowing in a first direction
from the first coolant inflow passage toward the first coolant
outflow passage to be different from a flow resistance of the
coolant flowing in a second direction from the second coolant
inflow passage toward the second coolant outflow passage.
9. The oil cooler according to claim 8, wherein the flow resistance
applying part is an offset fin that includes a plurality of
cut-and-raised parts, formed by cutting and raising a plate
partially and lined in the first direction, and the cut-and-raised
parts adjacent to each other in the first direction are offset from
each other.
10. The oil cooler according to claim 8, wherein the cut-and-raised
parts adjacent to each other in the first direction are offset in
the second direction that is perpendicular to the first direction,
the first coolant inflow passage is located opposite to the first
coolant outflow passage in the first direction with respect to the
offset fin, and the second coolant inflow passage is located at an
opposite side of the second coolant outflow passage with respect to
the offset fin in a third direction that bisects an angle between
the first direction and the second direction.
11. The oil cooler according to claim 7, further comprising a rib
provided between the first coolant inflow passage and the second
coolant inflow passage to restrict the coolant from flowing in
shortcut between the first coolant inflow passage and the second
coolant inflow passage.
12. The oil cooler according to claim 7, wherein the second coolant
inflow passage causes the coolant to flow toward the second coolant
outflow passage in a direction that intersects with a flow
direction of the oil.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] The present application is a continuation application of
International Patent Application No. PCT/JP2018/043173 filed on
Nov. 22, 2018, which designated the U.S. and claims the benefit of
priority from Japanese Patent Applications No. 2017-245714 filed on
Dec. 22, 2017. The entire disclosures of all of the above
applications are incorporated herein by reference.
TECHNICAL FIELD
[0002] The present disclosure relates to a cooling circuit and an
oil cooler.
BACKGROUND
[0003] An oil cooler of a cooling circuit includes a heat exchanger
core in which multiple plates are laminated with each other.
SUMMARY
[0004] According to an aspect of the present disclosure, a cooling
circuit may include a first coolant passage, a second coolant
passage, a thermostat, and an oil cooler. The oil cooler includes a
first coolant inflow port, a first coolant outflow port, a second
coolant inflow port, and a second coolant outflow port. The
thermostat may be configured to interrupt a flow of the coolant
flowing through the first coolant passage when a temperature of
coolant flowing into the thermostat is lower than a predetermined
temperature, and to allow the coolant to flow through the first
coolant passage and the second coolant passage, when the
temperature of the coolant is equal to or more than a predetermined
temperature.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] The above and other objects, features and advantages of the
present disclosure will become more apparent from the following
detailed description made with reference to the accompanying
drawings.
[0006] FIG. 1 is a block diagram showing a schematic structure of a
cooling circuit according to a first embodiment.
[0007] FIG. 2 is a view showing a cross-sectional structure of an
oil cooler according to the first embodiment.
[0008] FIG. 3 is a perspective view showing a structure of an
offset fin according to the first embodiment.
[0009] FIG. 4 is a block diagram showing an operation example of
the cooling circuit according to the first embodiment.
[0010] FIG. 5 is a time chart showing changes in a coolant
temperature of an engine and in an oil temperature of a
transmission according to the first embodiment.
[0011] FIG. 6 is a block diagram showing an another operation
example of the cooling circuit according to the first
embodiment.
[0012] FIG. 7 is a block diagram showing a structure of a cooling
circuit according to a second embodiment.
DETAILED DESCRIPTION
[0013] An oil cooler may include a heat exchanger core in which
multiple plates are laminated with each other, and a passage
control valve attached to a top portion of the heat exchanger core.
The passage control valve may include a valve housing brazed to a
top of the plates and a rotary valve. The passage control valve is
provided with a low-temperature coolant inflow port through which
coolant at a low temperature is supplied, a high-temperature
coolant inflow port through which the coolant at a high temperature
is supplied, and a coolant outflow port through which the coolant
returns.
[0014] A coolant inflow port and a coolant outflow port of the heat
exchanger core are configured to communicate with an interior of
the valve housing.
[0015] The passages of the oil cooler appropriately communicate
with each other in response to a rotational position of the rotary
valve, so that oil is heated or cooled in the oil cooler.
[0016] In the oil cooler described above, a flow rate of the
coolant used when the oil is heated is different from that used
when the oil is cooled. More specifically, the flow rate of the low
temperature coolant used to cool the oil tends to be larger than
the flow rate of the high temperature coolant used to heat the
oil.
[0017] In the oil cooler, the coolant is discharged from the single
coolant outflow port, during the oil heating in which the flow rate
of the coolant is relatively small, and during the oil cooling in
which the flow rate of the coolant is relatively large. Therefore,
a pressure loss of the coolant tends to be larger, in particular,
during the oil cooling in which the flow rate of the coolant is
relatively large.
[0018] If the pressure loss of the coolant becomes larger, the flow
rate of the coolant is decreased, and thereby causing a reduction
of heat exchange performance, an increase of a load of a pump, or
the like.
[0019] The present disclosure is provided with an oil cooler and a
cooling circuit configured to change a flow rate and reduce
pressure loss, for example.
[0020] According to an exemplary embodiment of the present
disclosure, a cooling circuit includes a first coolant passage in
which a coolant flows, a second coolant passage in which the
coolant flows, a thermostat, and an oil cooler configured to heat
or cool oil. The thermostat is configured to interrupt a flow of
the coolant flowing through the first coolant passage when a
temperature of coolant flowing into the thermostat is lower than a
predetermined temperature, and to allow the coolant to flow through
the first coolant passage, when the temperature of the coolant is
equal to or higher than a predetermined temperature.
[0021] For example, the oil cooler may include a first coolant
inflow port, a first coolant outflow port, a second coolant inflow
port, and a second coolant outflow port. The coolant flowing in the
first coolant passage flows into the first coolant inflow port. The
coolant flowing in the inner passage of the oil cooler flows out of
the oil cooler through the first coolant outflow port, and returns
the first coolant passage. The coolant flowing in the second
coolant passage flows into the second coolant inflow port of the
oil cooler. The coolant flowing into the oil cooler from the second
coolant inflow port flows out of the oil cooler through the second
coolant outflow port. The oil cooler is configured to heat or cool
the oil by heat exchange between the coolant flowing from the first
coolant inflow port or/and the second coolant inflow port and the
oil.
[0022] For example, when the thermostat interrupts the flow of the
coolant in the first coolant passage, only the coolant in the
second coolant passage flows into the oil cooler. On the other
hand, when the thermostat allows the coolant to flow through the
first coolant passage, the coolant in both the first coolant
passage and the second coolant passage flows into the oil cooler.
Therefore, a flow rate of the coolant flowing in the oil cooler can
be suitably changed.
[0023] In addition, the coolant is enabled to flow out from the oil
cooler through both of the first coolant outflow port and the
second coolant outflow port. Therefore, pressure loss of the
coolant can be reduced, compared to an oil cooler which includes a
single outflow port.
[0024] According to another exemplary embodiment of the present
disclosure, an oil cooler is configured by a plurality of plates
laminated to define an oil passage through which an oil flows and a
coolant passage through which coolant flows, and the oil passage
and the coolant passage are arranged alternatively. The oil cooler
includes a plurality of coolant plates defining the coolant passage
therein. The coolant plates define an inner passage in which the
coolant flows, a first coolant inflow passage through which the
coolant flows into the inner passage, a second coolant inflow
passage through which the coolant flows into the inner passage, a
first coolant outflow passage through which the coolant in the
inner passage flows out, and a second coolant outflow passage
through which the coolant in the inner passage flows out. The inner
passage is configured to communicate with both the first coolant
inflow passage and the second coolant inflow passage and to
communicate with the first coolant outflow passage and the second
coolant outflow passage, so that the coolant flows into the inner
passage only through the second coolant inflow port when a flow of
the coolant flowing into the first coolant inflow passage is
closed, and the coolant flows into the inner passage through both
of the first coolant inflow port and the second coolant inflow port
when the coolant flows into the first coolant inflow passage and
the second coolant inflow passage.
[0025] For example, when the coolant does not flow into the first
coolant inflow passage, the coolant flows into the inner passage
from only the second coolant inflow passage. On the other hand,
when the coolant flows into the first coolant inflow passage, the
coolant flows into the inner passage of the oil cooler from both
the first coolant inflow passage and the second coolant inflow
passage. Therefore, a flow rate of the coolant flowing through the
inner passage can be suitably changed.
[0026] In addition, the coolant is enabled to flow out from the oil
cooler through both of the first coolant outflow passage and the
second coolant outflow passage. Therefore, the pressure loss of the
coolant can be reduced in the oil cooler.
[0027] Embodiments of a cooling circuit and an oil cooler will be
described with reference to the drawings as follows. The same
reference numerals in the drawings are given to the same structures
in order to eliminate explanation for easily understanding.
First Embodiment
[0028] A cooling circuit and an oil cooler according to a first
embodiment will be described below.
[0029] FIG. 1 shows a cooling circuit 10 in the present embodiment.
The cooling circuit 10 is equipped in a vehicle and includes an
engine cooling circuit 20 in which coolant for an engine 40
circulates, and a transmission cooling circuit 30 in which
hydraulic oil of a transmission 50 circulates. The engine cooling
circuit 20 includes the engine 40, a radiator 41, a heater core 42,
a thermostat 43, and a coolant pump 44.
[0030] A coolant passage W20 couples the engine 40 to the radiator
41. In addition, a coolant passage W21 couples the engine 40 to the
heater core 42. Because of this, the coolant which has exchanged
heat with the engine 40 is enabled to flow to at least one of the
radiator 41 and the heater core 42 through the coolant passage W20
or/and the coolant passage W21.
[0031] In the present embodiment, the coolant passage W20
corresponds to a first coolant passage, and the coolant which flows
in the coolant passage W20 corresponds to a first coolant.
[0032] The radiator 41 is configured to cool the coolant by heat
exchange between the coolant which flows through an inside of the
radiator 41 and air which flows through an outside of the radiator
41. The coolant cooled by the radiator 41 flows into the coolant
pump 44 through a coolant passage W22.
[0033] The coolant pump 44 is a mechanical pump which is driven by
power transferred from the engine 40 or an electric pump which is
driven by electric power supplied from a battery equipped in the
vehicle. The coolant pump 44 is configured to pressure-send the
coolant flowing in the coolant pump 44 to the engine 40 and to
circulate the coolant to components in the engine cooling circuit
20. The heater core 42 is an element of an air conditioner for a
vehicle.
[0034] The heater core 42 is configured to perform the heat
exchange between the coolant supplied from the engine 40 and the
air flowing in an air conditioning duct of the air conditioner and
to heat the air flowing in the air conditioning duct. The air
conditioner heats a vehicle interior by a blowout of the heated air
to the vehicle interior through the air conditioning duct. The
coolant flowing out of the heater core 42 flows into the thermostat
43 through a coolant passage W23.
[0035] In the present embodiment, the coolant passage W23
corresponds to a second coolant passage, and the coolant which
flows in the coolant passage W23 corresponds to a second
coolant.
[0036] The thermostat 43 is provided at an intermediate location of
the coolant passage W22 which couples the radiator 41 to the engine
40. When a coolant temperature is lower than a predetermined valve
opening temperature Tth1, the thermostat 43 becomes a closed state
and shuts off the coolant passage W22. The valve opening
temperature Tth1 is set at, for example, 80 Celsius.
[0037] When the coolant temperature is lower than the valve opening
temperature Tth1, the coolant is allowed to flow from the heater
core 42 to the engine 40, while the coolant flowing from the
radiator 41 to the engine 40 is interrupted.
[0038] When the coolant temperature is equal to or higher than the
valve opening temperature Tth1, the thermostat 43 becomes in an
open state, and the coolant passage W22 is opened. When the coolant
temperature is equal to or higher than the valve opening
temperature Tth1, the coolant is allowed to flow from the heater
core 42 to the engine 40 and to flow from the radiator 41 to the
engine 40.
[0039] When the coolant temperature becomes higher than a valve
full-opening temperature Tth2 higher than the valve opening
temperature Tth1, the thermostat 43 becomes a full-open state.
[0040] In the engine cooling circuit 20, when the coolant
temperature is low such as in case of a cold start of the engine
40, the thermostat 43 becomes in the closed state. Because of this,
the coolant pressure-sent by the coolant pump 44 is circulated
through the engine 40 and the heater core 42, while bypassing the
radiator 41.
[0041] In this case, because the radiator 41 does not cool the
coolant, the coolant temperature is easily raised for a short time
period. As a result, the engine 40 and the heater core 42 can be
easily warmed for a short time.
[0042] Subsequently, when the coolant temperature is raised to or
above the valve opening temperature Tth1, the thermostat 43 becomes
in the open state. Thus, the coolant pressure-sent by the coolant
pump 44 is circulated through the engine 40, the radiator 41, and
the heater core 42.
[0043] Because of this, the coolant cooled by the radiator 41 is
supplied to the engine 40, and the engine 40 is cooled by the heat
exchange with the coolant. A part of the coolant heated by the
engine 40 is supplied to the heater core 42, and the heater core 42
is maintained in high temperature. Therefore, the heater core 42 is
enabled to heat the air which flows in the air conditioning
duct.
[0044] The transmission cooling circuit 30 includes the
transmission 50, an oil cooler 51, and an oil pump 52. An oil
passage W30 couples the transmission 50 to an oil inflow port 510a
of the oil cooler 51. The oil flowing out of the transmission 50
flows into the oil inflow port 510a of the oil cooler 51 through
the oil passage W30.
[0045] The oil cooler 51 includes the oil inflow port 510a, a first
coolant inflow port 511a, a second coolant inflow port 512a, an oil
outflow port 510b, a first coolant outflow port 511b, and a second
coolant outflow port 512b. The oil flowing into the oil inflow port
510a flows in the oil cooler 51 and is discharged from the oil
outflow port 510b. The oil discharged from the oil outflow port
510b flows into the oil pump 52 through an oil passage W31.
[0046] The oil pump 52 is, for example, an electric pump driven by
the electric power supplied from a battery equipped in the vehicle.
The oil pump 52 is configured to pump and pressure-send the oil to
the transmission 50 and to circulate the oil through components in
the transmission cooling circuit 30.
[0047] A bypass passage W40 couples the first coolant inflow port
511a of the oil cooler 51 to the coolant passage W20. Because of
this, a part of the coolant flowing in the coolant passage W20,
that is, a part of the coolant discharged from the engine 40 flows
into the oil cooler 51 through the bypass passage W40.
[0048] A check valve 45 is disposed at an intermediate location in
the bypass passage W40. The check valve 45 is configured to allow
the coolant to flow from the coolant passage W20 toward the first
coolant inflow port 511a, while preventing the flow of the coolant
from the first coolant inflow port 511a toward the coolant passage
W20. In the present embodiment, the check valve 45 corresponds to a
flow controller.
[0049] A bypass passage W41 couples the second coolant inflow port
512a of the oil cooler 51 to the coolant passage W23. Because of
this, a part of the coolant flowing in the coolant passage W23,
that is, a part of the coolant discharged from the heater core 42,
flows into the oil cooler 51 through the bypass passage W41.
[0050] The coolant flowing into the oil cooler 51 from at least one
of the first coolant inflow port 511a and the second coolant inflow
port 512a exchanges the heat with the oil flowing in the oil cooler
51. Therefore, the oil is heated or cooled in the oil cooler 51.
The coolant flowing through the oil cooler 51 is discharged from
the first coolant outflow port 511b or the second coolant outflow
port 512b.
[0051] A bypass passage W42 couples the first coolant outflow port
511b to the coolant passage W20 at a downstream side of a
connection portion at which the coolant passage W20 is connected to
the bypass passage W40. Therefore, the coolant discharged from the
first coolant outflow port 511b flows into the coolant passage W20
through the bypass passage W42.
[0052] A bypass passage W43 couples the second coolant outflow port
512b to the coolant passage W23 at a downstream side of a
connection portion at which the coolant passage W23 is connected to
the bypass passage W41. Therefore, the coolant discharged from the
second coolant outflow port 512b flows into the coolant passage W23
after being heat exchanged with the oil in the oil cooler 51.
[0053] A detailed structure of the oil cooler 51 will be described
below.
[0054] Multiple plates are laminated in the oil cooler 51 such that
the oil passage through which the oil flows and the coolant passage
through which the coolant flows are arranged alternatively.
[0055] FIG. 2 shows a cross-sectional structure of a coolant plate
70 which forms the coolant passage of the oil cooler 51. As shown
in FIG. 2, the cross-sectional structure of each coolant plate 70
has approximately a hexagon shape in a section perpendicular to a
lamination direction in which the plates are laminated. An inner
passage 77 is formed in the coolant plate 70, and the coolant flows
in the inner passage 77. The coolant plate 70 includes a first
coolant inflow passage 72a, a second coolant inflow passage 73a, a
first coolant outflow passage 72b, and a second coolant outflow
passage 73b, which are provided to communicate with the inner
passage 77.
[0056] The coolant plate 70 further includes an oil inflow passage
71a and an oil outflow passage 71b which are not connected to the
inner passage 77. That is, the oil inflow passage 71a and the oil
outflow passage 71b are separated from the inner passage 77. The
first coolant inflow passage 72a is provided at a corner C1 of the
coolant plate 70. Two corners C2, C3 are located adjacent to the
corner C1 in the coolant plate 70. The oil outflow passage 71b and
the second coolant inflow passage 73a are provided at the corner C2
and the corner C3, respectively.
[0057] Corners C4 to C6 are formed at diagonal positions of the
corners C1 to C3, respectively, in the coolant plate 70. The first
coolant outflow passage 72b, the oil inflow passage 71a, and the
second coolant outflow passage 73b are provided at the corner C4,
the corner C5, and the corner C6, respectively.
[0058] An internal diameter of the first coolant inflow passage 72a
is larger than an internal diameter of the second coolant inflow
passage 73a. Similarly, an internal diameter of the first coolant
outflow passage 72b is larger than an internal diameter of the
second coolant outflow passage 73b.
[0059] Hereinafter, a direction from the first coolant inflow
passage 72a toward the first coolant outflow passage 72b is
referred to as X direction, while a direction perpendicular to the
X direction is referred to as Y direction, as shown in FIG. 2. In
addition, a direction from the second coolant inflow passage 73a
toward the second coolant outflow passage 73b, that is, a direction
in which an angle between the X direction and the Y direction is
bisected is referred to as a direction.
[0060] In the present embodiment, the X direction corresponds to a
first direction, the Y direction corresponds to a second direction,
and the a direction corresponds to a third direction. An offset fin
74 is disposed at the coolant inner passage 77 of the coolant plate
70. As shown in FIG. 3, the offset fin 74 includes multiple
cut-and-raised parts 740 in the X direction. Each cut-and-raised
part 740 is formed by cutting and raising a plate partially. The
offset fin 74 is opened in the X direction. The cut-and-raised
parts 740, 740 adjacent to each other in the X direction are offset
in the Y direction.
[0061] In the offset fin 74, when the coolant flows in the X
direction shown in FIG. 2, that is, when the coolant flows from the
first coolant inflow passage 72a toward the first coolant outflow
passage 72b, the coolant flows in the cut-and-raised part 740 and
through a clearance between the cut-and-raised parts 740, 740
adjacent to each other. Therefore, a flow resistance against the
coolant is small.
[0062] On the other hand, when the coolant flows in the a
direction, that is, when the coolant flows from the second coolant
inflow passage 73a toward the second coolant outflow passage 73b,
the coolant tends to collide to the cut-and-raised part 740, and
the flow resistance against the coolant becomes larger. In the
present embodiment, the offset fin 74 corresponds to a flow
resistance applying part configured to apply a flow resistance to a
fluid.
[0063] A rib 75 is located between the first coolant inflow passage
72a and the second coolant inflow passage 73a at the coolant plate
70 and extends from an inner wall of the coolant plate 70 to an
inside. The rib 75 is disposed to restrict the coolant from flowing
through a shortcut circuit between the first coolant inflow passage
72a and the second coolant inflow passage 73a.
[0064] A rib 76 is located between the first coolant outflow
passage 72b and the second coolant outflow passage 73b at the
coolant plate 70 and extends from the inner wall of the coolant
plate 70 to an inside. The rib 76 restricts the coolant from
flowing through the shortcut circuit between the first coolant
outflow passage 72b and the second coolant outflow passage 73b.
[0065] In the oil cooler 51, the oil flows from the oil inflow port
510a shown in FIG. 1 into the oil inflow passage 71a shown in FIG.
2. The oil flowing into the oil inflow passage 71a flows into an
oil inner passage formed in an oil plate which is adjacent to the
coolant plate 70. The oil flowing in the oil inner passage flows in
a direction shown by an arrow D1 in FIG. 2. The oil flows in a flow
direction D1 that intersects with a flow direction D2 of the
coolant which flows from the first coolant inflow passage 72a
toward the first coolant outflow passage 72b. The oil flowing into
the oil inner passage is discharged from the oil outflow port 510b
shown in FIG. 1 through the oil outflow passage 71b.
[0066] Next, operation examples of the cooling circuit 10 and the
oil cooler 51 in the present embodiment will be described
below.
[0067] When the temperature of the coolant flowing in the engine
cooling circuit 20 is lower than the valve opening temperature
Tth1, such as in the cold start of the engine 40, the thermostat 43
is in the closed state.
[0068] In this case, as shown by a thick line in FIG. 4, the
coolant circulates through the engine cooling circuit 20. That is,
the coolant circulates through the engine 40, the heater core 42,
the oil cooler 51, the thermostat 43, and the coolant pump 44,
while does not circulate through the radiator 41. In this case, the
coolant heated by the heat exchange with the engine 40 flows into
the second coolant inflow port 512a of the oil cooler 51 through
the coolant passage W21, the heater core 42, the coolant passage
W23 and the bypass passage W41 in this order, and flows in the
coolant inner passage 77 of the oil cooler 51.
[0069] The oil is heated by the heat exchange between the coolant
flowing in the coolant inner passage 77 of the oil cooler 51 and
the oil flowing in the oil inner passage. Thus, the oil flowing in
the transmission 50 can be heated.
[0070] The coolant in which the temperature is reduced by the heat
exchange with the oil is discharged to the bypass passage W43
through the second coolant outflow passage 73b and the second
coolant outflow port 512b. The coolant discharged to the bypass
passage W43 is heated again by flowing into the engine 40 through
the coolant passage W23, the thermostat 43, and the coolant pump
44.
[0071] In the oil cooler 51, the coolant flows from the second
coolant inflow passage 73a toward the second coolant outflow
passage 73b and tends to receive the flow resistance from the
offset fin 74. Therefore, a flow rate of the coolant which flows in
the oil cooler 51 is reduced.
[0072] As shown in FIG. 5, for example, when the operation of the
engine 40 starts at a time t10, a coolant temperature Te of the
engine 40 is increased for a shorter period, compared to an oil
temperature Tt of the transmission 50. Thereby, a temperature
difference .DELTA.T between the coolant temperature Te of the
engine 40 and the oil temperature Tt of the transmission 50 becomes
larger, and the oil can be heated even in a case where the flow
rate of the coolant flowing in the oil cooler 51 is low.
[0073] Subsequently, when the temperature of the coolant flowing in
the engine coolant circuit 20 is increased to or above the valve
opening temperature Tth1, the thermostat 43 becomes in the valve
open state. In this state, the coolant circulates through the
engine coolant circuit 20 as shown by a thick line in FIG. 6. That
is, the coolant can circulate through the all components in the
engine coolant circuit 20 in FIG. 6.
[0074] In this case, the coolant cooled at the radiator 41 flows
into the first coolant inflow port 511a of the oil cooler 51
through the engine 40, the coolant passage W20, and the bypass
passage W40.
[0075] In addition, the coolant flowing in the coolant passage W23
flows into the second coolant inflow port 512a of the oil cooler 51
through the bypass passage W41. The coolant flowing into the first
coolant inflow port 511a and the coolant flowing into the second
coolant inflow port 512a flow through the coolant inner passage 77
of the oil cooler 51, respectively.
[0076] Thus, the oil is cooled by the heat exchange between the
coolant flowing in the coolant inner passage 77 and the oil flowing
in the oil inner passage in the oil cooler 51. That is, the oil
flowing in the transmission 50 is cooled.
[0077] As shown in FIG. 5, the oil temperature Tt of the
transmission 50 is reduced, at a time t11 at which the coolant
temperature exceeds the valve opening temperature Tth1 and
thereafter.
[0078] The coolant heated by the heat exchange with the oil is
discharged to the bypass passage W42 through the first coolant
inflow passage 72a and the first coolant outflow port 511b or to
the bypass passage W43 through the second coolant outflow passage
73b and the second coolant outflow port 512b.
[0079] The coolant discharged to the bypass passage W42 flows into
the radiator 41 through the coolant passage W20 and is cooled again
in the radiator 41.
[0080] In the cooling circuit 10 and the oil cooler 51 of the
present embodiments described above, operational effects shown by
(1) to (6) can be obtained.
[0081] (1) When the thermostat 43 interrupts the flow of the
coolant in the coolant passage W20, the coolant does not flow into
the first coolant inflow passage 72a of the oil cooler 51 and flows
into the inner passage 77 of the oil cooler 51 through only the
second coolant inflow passage 73a. On the other hand, when the
thermostat 43 allows the coolant to flow through the coolant
passage W20, the coolant flows into the inner passage 77 of the oil
cooler 51 through the first coolant inflow passage 72a and the
second coolant inflow passage 73a.
[0082] Therefore, the flow rate of the coolant flowing in the oil
cooler 51 can be changed. In addition, the coolant is enabled to
flow out from the oil cooler 51 through the first coolant outflow
port 511b and the second coolant outflow port 512b and through the
first coolant outflow passage 72b and the second coolant outflow
passage 73b. Therefore, the pressure loss of the coolant can be
effectively reduced, compared to a known oil cooler which includes
a single outflow port and a single outflow passage.
[0083] (2) The check valve 45 is provided in the bypass passage W40
which couples the first coolant inflow port 511a of the oil cooler
51 to the coolant passage W20. The check valve 45 is configured to
check and regulate the flow of the coolant from the first coolant
inflow port 511a of the oil cooler 51 toward the coolant passage
W20.
[0084] Because of this, when the thermostat 43 is in the closed
state, a reverse flow of the coolant from the inner passage 77 of
the oil cooler 51 toward the coolant passage W20 can be
prevented.
[0085] (3) In the oil cooler 51, the coolant flowing into the first
coolant inflow passage 72a from the first coolant inflow port 511a
is discharged from the first coolant outflow port 511b through the
first coolant outflow passage 72b.
[0086] The coolant flows in the flow direction D2 that intersects
with the flow direction D1 of the oil in the oil cooler 51.
Therefore, the heat exchange between the coolant and the oil can be
performed more efficiently, and a cooling efficiency of the oil can
be enhanced.
[0087] (4) The coolant plate 70 of the oil cooler 51 includes the
offset fins 74. The offset fins 74 are configured to cause a flow
resistance against the coolant when the coolant flows in the X
direction from the first coolant inflow passage 72a toward the
first coolant outflow passage 72b to be different from a flow
resistance against the coolant when the coolant flows in the a
direction from the second coolant inflow passage 73a toward the
second coolant outflow passage 73b.
[0088] More specifically, the flow resistance of the coolant
flowing in the a direction from the second coolant inflow passage
73a toward the second coolant outflow passage 73b is larger than
the flow resistance of the coolant flowing in the X direction from
the first coolant inflow passage 72a toward the first coolant
outflow passage 72b. Therefore, the coolant tends to flow from the
first coolant inflow passage 72a toward the first coolant outflow
passage 72b, and the coolant in the oil cooler 51 tends to flow to
the radiator 41. As a result, the coolant in the cooling circuit 10
can be cooled more easily, and the cooling efficiency of the
cooling circuit 10 can be enhanced.
[0089] In addition, the difference between the flow resistances in
two directions can be caused easily by an arrangement of the offset
fin 74 in the coolant plate 70.
[0090] (5) In the oil cooler 51, the first coolant inflow passage
72a is located opposite to the first coolant outflow passage 72b
with respect to the offset fins 74 in the X direction. In addition,
the second coolant inflow passage 73a is located to the second
coolant outflow passage 73b with respect to the offset fins in the
a direction. Therefore, while high heat exchange efficiency between
the coolant and the oil can be maintained, the flow resistance of
the coolant flowing in the X direction can be kept different from
the flow resistance of the coolant flowing in the a direction.
[0091] (6) The rib 75 is provided between the first coolant inflow
passage 72a and the second coolant inflow passage 73a in the oil
cooler 51. The rib 75 enables to restrict the coolant flowing in
the shortcut between the first coolant inflow passage 72a and the
second coolant inflow passage 73a, and a reduction of heat exchange
performance of the oil cooler 51 can be restricted.
Second Embodiment
[0092] Next, a cooling circuit 10 in a second embodiment will be
described. In the second embodiment, difference parts with the
cooling circuit 10 in the first embodiment will be mainly described
below. The engine 40 in the present embodiment is an engine with a
supercharger.
[0093] As shown in FIG. 7, the cooling circuit 10 in the present
embodiment includes a CAC cooling circuit 80 through which a
coolant from a charge air cooler (CAC) 81 circulates, instead of
the circuit which includes the heater core 42 described in the
first embodiment. The CAC cooling circuit 80 includes the CAC 81, a
low temperature coolant radiator 82, a coolant pump 83, and a
thermostat 84.
[0094] The CAC 81 is configured to raise air density by cooling
intake air compressed by a supercharged engine 40. The coolant
circulates between the CAC 81 and the low temperature coolant
radiator 82 through coolant passages W50, W51.
[0095] The low temperature coolant radiator 82 is configured to
cool the coolant by heat exchange between the coolant flowing in
the low temperature coolant radiator 82 and air flowing outside of
the low temperature coolant radiator 82. The coolant pump 83 is
provided in the coolant passage W51. The coolant pump 83 is
configured to circulate the coolant in the CAC cooling circuit
80.
[0096] A coolant passage W52 couples the second coolant inflow port
512a of the oil cooler 51 to the coolant passage W50. In addition,
a coolant passage W53 couples the second coolant outflow port 512b
of the oil cooler 51 to the coolant passage W51.
[0097] In the present embodiment, the coolant passage W52
corresponds to the second coolant passage, and the coolant flowing
in the coolant passage W52 corresponds to the second coolant.
[0098] The thermostat 84 is located at a position at which the
coolant passage W50 is connected to the coolant passage W52. The
thermostat 84 is configured to become in a closed state when the
coolant temperature is lower than a predetermined temperature and
to interrupt the coolant flow in the coolant passage W50.
[0099] On the other hand, the thermostat 84 is configured to become
in an opened state when the coolant temperature is at or above a
predetermined temperature and to allow the coolant to flow through
the coolant passage W50 when the thermostat 84 is in the opened
state.
[0100] In the cooling circuit 10 of the present embodiment, a
cooling circuit W24 couples the coolant passage W20 to the coolant
passage W22. The cooling circuit W24 is a passage through which the
coolant flowing in the coolant passage W20 bypasses the radiator 41
and flows to the coolant passage W22.
[0101] According to the structure described above, when the
thermostats 43, 84 are in the closed state, the coolant which has
been heated by the heat exchange at the CAC 81 is supplied to the
oil cooler 51. Therefore, the oil cooler 51 enables to heat the oil
by the heat exchange between the coolant and the oil.
Other Embodiments
[0102] Embodiments may be suitably modified to have structures
described below. For example, an electromagnetic valve may be
provided in the bypass passage W40 as a flow controller which
regulates the flow of the coolant, instead of the check valve 45.
The oil cooled by the oil cooler 51 is not limited to the oil used
for the transmission 50 and may be oil used for a power machine
such as the engine 40.
[0103] The cooling circuit 10 may cool an electromotor equipped in
the vehicle, an inverter to drive the electromotor, or the like,
instead of the engine 40. The coolant plate 70 may include a
suitable structure other than the offset fins as the flow
resistance applying part. The present disclosure is not limited by
above examples.
[0104] The present disclosure encompasses various variations and
modifications to above examples including features of the present
disclosure, even if a skilled person modifies. The present
disclosure is not limited by the elements, the locations, the
conditions, the shapes or the like in above examples and can be
modified. Each elements in the examples may be combined suitably
except for a case where a technical inconsistency occurs.
* * * * *