U.S. patent application number 15/772139 was filed with the patent office on 2018-12-13 for cooling system for internal combustion engine.
This patent application is currently assigned to AISIN SEIKI KABUSHIKI KAISHA. The applicant listed for this patent is AISIN SEIKI KABUSHIKI KAISHA. Invention is credited to Yojiro Koga, Tadayoshi Sato.
Application Number | 20180355784 15/772139 |
Document ID | / |
Family ID | 58764131 |
Filed Date | 2018-12-13 |
United States Patent
Application |
20180355784 |
Kind Code |
A1 |
Koga; Yojiro ; et
al. |
December 13, 2018 |
COOLING SYSTEM FOR INTERNAL COMBUSTION ENGINE
Abstract
A cooling system for an internal combustion engine includes a
coolant flow passage through which coolant flows between the
internal combustion engine and a heat exchanger, a flow amount
control valve incorporated in the coolant flow passage and
configured to control flow of the coolant flowing in the coolant
flow passage, and a control section configured to effect switchover
from a full opened state to a full closed state of the flow amount
control valve based on a supply of a negative pressure produced in
the internal combustion engine and to effect also switchover from
the full closed state to the full opened state over a second period
longer than a first period required for the switchover for the flow
amount control valve from the full closed state to the full opened
state, in response to stop of the supply of the negative
pressure.
Inventors: |
Koga; Yojiro; (Kariya-shi,
Aichi, JP) ; Sato; Tadayoshi; (Chita-gun, Aichi,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
AISIN SEIKI KABUSHIKI KAISHA |
Kariya-shi, Aichi |
|
JP |
|
|
Assignee: |
AISIN SEIKI KABUSHIKI
KAISHA
Kariya-shi, Aichi-ken
JP
|
Family ID: |
58764131 |
Appl. No.: |
15/772139 |
Filed: |
November 15, 2016 |
PCT Filed: |
November 15, 2016 |
PCT NO: |
PCT/JP2016/083790 |
371 Date: |
April 30, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F01P 7/167 20130101;
F01P 2007/146 20130101; F01P 7/14 20130101; F16K 31/126
20130101 |
International
Class: |
F01P 7/14 20060101
F01P007/14 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 24, 2015 |
JP |
2015-228531 |
Claims
1. A cooling system for an internal combustion engine, the cooling
system comprising: a coolant flow passage through which coolant
flows between the internal combustion engine and a heat exchanger;
a flow amount control valve incorporated in the coolant flow
passage and configured to control flow of the coolant flowing in
the coolant flow passage; and a control section configured to
effect switchover from a full opened state to a full closed state
of the flow amount control valve based on a supply of a negative
pressure produced in the internal combustion engine and to effect
also switchover from the full closed state to the full opened state
over a second period longer than a first period required for the
switchover for the flow amount control valve from the full closed
state to the full opened state, in response to stop of the supply
of the negative pressure.
2. The cooling system for an internal combustion engine of claim 1,
wherein: the system further comprises a switching valve for
switching a pressure to be fed to the control section to either one
of a first pressure comprised of the negative pressure produced in
the internal combustion engine or a second pressure higher than the
first pressure; and a constricted portion for constricting an
opening area of a feed passage for feeding a fluid having the
second pressure to the switching valve is incorporated in the feed
passage.
3. The cooling system for an internal combustion engine of claim 1,
wherein the control section is configured such that when the flow
amount control valve is switched from the full closed state to the
full opened state, the control section firstly provides alternation
between the full closed state and a released state of the full
closed state and then provides switchover to the full opened
state.
4. The cooling system for an internal combustion engine of claim 1,
wherein: the flow amount control valve includes: a communication
passage for communicating an inlet port through which the coolant
enters the flow amount control valve to an outlet port through
which the coolant flows out of the flow amount control valve; and a
bypass passage that communicates the inlet port to the outlet port,
with bypassing the communication passage; and the control section
firstly establishes communication between the inlet port and the
outlet port via the bypass passage and then establishes
communication between the inlet port and the outlet port via the
communication passage.
Description
TECHNICAL FIELD
[0001] This invention relates to a cooling system for an internal
combustion engine for controlling flow of coolant between the
internal combustion engine and a heat exchanger.
BACKGROUND ART
[0002] Conventionally, an internal combustion engine, for realizing
improvement of driving or fuel consumption efficiency under an
optimal condition, promotes a warm-up operation at a cold time and
implements a cooling operation at a hot time. Specifically, when
the temperature of coolant is low, control is effected not to flow
the coolant to e.g. a radiator, thus promoting warm-up of the
internal combustion engine; and when the temperature of coolant is
high, the coolant is allowed to flow to e.g. the radiator, thus
controlling the temperature of the coolant to an optimal
temperature for fuel combustion. A technique usable in this type of
technique is disclosed in e.g. Patent Document 1.
[0003] A cooling water control valve disclosed in Patent Document 1
includes, in its casing, a valve body for controlling a flow amount
of cooling water (corresponding to "coolant" described above) and
an actuator for driving this valve body. The actuator is configured
to be capable of adjusting an opening degree of an opening portion
of the valve body, for effecting a flow amount control of the
cooling water.
BACKGROUND ART DOCUMENT
Patent Document
[0004] Patent Document 1: Japanese Unexamined Patent Application
Publication No. 2013-249810
SUMMARY OF THE INVENTION
Problem to be Solved by Invention
[0005] The technique disclosed in Patent Document 1 controls an
opening portion of a valve body by a motor actuator, so flow amount
adjustment of cooling water can vary from a very small amount to a
large flow amount. However, since the technique requires provision
of the motor actuator, it can result in cost increase. Further, for
fine adjustment of the flow amount, a sensor or the like needs to
be provided for detecting the opening degree of the valve body.
This can result in further increase of the cost.
[0006] Then, there is a need for a cooling system for an internal
combustion engine that can control flow of coolant at a low
cost.
Solution
[0007] According to a characterizing feature of a cooling system
for an internal combustion engine relating to the present
invention, the cooling system comprises:
[0008] a coolant flow passage through which coolant flows between
the internal combustion engine and a heat exchanger;
[0009] a flow amount control valve incorporated in the coolant flow
passage and configured to control flow of the coolant flowing in
the coolant flow passage; and
[0010] a control section configured to effect switchover from a
full opened state to a full closed state of the flow amount control
valve based on a supply of a negative pressure produced in the
internal combustion engine and to effect also switchover from the
full closed state to the full opened state over a second period
longer than a first period required for the switchover for the flow
amount control valve from the full closed state to the full opened
state, in response to stop of the supply of the negative
pressure.
[0011] With the above-described characterizing feature, the flow
amount control valve can be controlled by a negative pressure
produced in the internal combustion engine. Thus, there is no need
to additionally provide a motor actuator or an angle senor, etc.
Thus, the flow (communication) of coolant can be controlled
inexpensively. Further, with the above arrangement, it is possible
to delay the response in the switchover of the flow amount control
valve from the full closed state to the full opened state, as
compared with a conventional flow amount control valve. Therefore,
it is possible to prevent non-warmed coolant from flowing at one
time altogether through the flow amount control valve, so that
re-cooling of once warmed-up internal combustion engine or coolant
can be suppressed.
[0012] Preferably, the system further comprises:
[0013] a switching valve for switching a pressure to be fed to the
control section to either one of a first pressure comprised of the
negative pressure produced in the internal combustion engine or a
second pressure higher than the first pressure; and a constricted
portion for constricting an opening area of a feed passage for
feeding a fluid having the second pressure to the switching valve
is incorporated in the feed passage.
[0014] With the above-described arrangement, it is readily possible
for the constricted portion to realize a configuration for setting
an opening area of a feed passage for feeding fluid having the
second pressure smaller than an opening area of the feed passage
for feeding fluid having the first pressure. Therefore, the
above-described response relating to the switchover from the full
closed state to the full opened state can be realized at low
cost.
[0015] Still preferably, the control section is configured such
that when the flow amount control valve is switched from the full
closed state to the full opened state, the control section firstly
provides alternation between the full closed state and a released
state of the full closed state and then provides switchover to the
full opened state.
[0016] With the above-described arrangement, the arrangement of
delaying the response for the switchover from the full closed state
to the full opened state can be provided through control
scheme.
[0017] Further preferably:
[0018] the flow amount control valve includes: [0019] a
communication passage for communicating an inlet port through which
the coolant enters the flow amount control valve to an outlet port
through which the coolant flows out of the flow amount control
valve; and [0020] a bypass passage that communicates the inlet port
to the outlet port, with bypassing the communication passage;
and
[0021] the control section firstly establishes communication
between the inlet port and the outlet port via the bypass passage
and then establishes communication between the inlet port and the
outlet port via the communication passage.
[0022] With the above-described arrangement, prior to communication
(flow) of coolant via the communication passage, communication of
coolant can be established via the bypass passage. Therefore, by
setting the flow amount of coolant that flows via the bypass
passage smaller than the flow amount of coolant that flows via the
communication passage, the above-described arrangement of delaying
response can be realized. Incidentally, such bypass passage can be
realized by setting the flow amount area of the bypass passage
smaller than that of the communication passage or by intermittent
adjustment of the valve opening period of the bypass passage.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 is a diagram showing a configuration of a cooling
system for an internal combustion engine,
[0024] FIG. 2 is a view showing one example of a flow amount
control of coolant,
[0025] FIG. 3 is a diagram showing a configuration of a cooling
system for an internal combustion engine according to a further
embodiment,
[0026] FIG. 4 is a view showing a flow amount control of coolant
according to the further embodiment,
[0027] FIG. 5 is a view showing a flow amount control of coolant
according to a still further embodiment.
EMBODIMENTS
[0028] A cooling system for an internal combustion engine relating
to the present invention controls flow (communication) of coolant
by utilizing a negative pressure produced in the internal
combustion engine. Next, a cooling system 1 for an internal
combustion engine of this embodiment (to be referred to simply as a
"cooling system" hereinafter) will be explained.
[0029] FIG. 1 is a block diagram schematically showing a
configuration of the cooling system 1 relating to this embodiment.
As shown in FIG. 1, the cooling system 1 includes a coolant flow
passage 10, a flow amount control valve 20, a control section 30
and a switching valve 40.
[0030] The coolant flow passage 10 communicates coolant between an
internal combustion engine 2 and a heat exchanger 3. Here, the
"internal combustion engine 2" refers to an engine mounted on a
vehicle and configured to output power by combusting fuel such as
gasoline, etc. The "heat exchanger 3" refers to a heater core for
effecting heat exchange with coolant. For instance, in case warm-up
of the heat exchanger 3 is needed at e.g. the time of start of the
internal combustion engine 2, communication of the coolant to the
heat exchanger 3 is stopped for promoting the warm-up of this heat
exchanger 3. With this, when warm-up of inside of a vehicle cabin
is to be effected for instance, it is possible to reduce a time
period required until warm or hot air can be supplied into the
vehicle cabin. On the other hand, when such warm-up of the heat
exchanger 3 is not needed, coolant can be communicated to the heat
exchanger 3 for cooling this heat exchanger 3.
[0031] Further, when cooling of the internal combustion engine 2
becomes necessary, the coolant is communicated to a radiator 4 for
cooling the internal combustion engine 2. Such communications of
coolant to the heat exchanger 3 or to the radiator 4 are effected
by a water pump 5. And, according to a temperature of the coolant
detected by a water temperature sensor 6, a thermostat valve 7 is
controlled to set whether the coolant is to be communicated to the
heat exchanger 3 or to the radiator 4.
[0032] The flow amount control valve 20 is incorporated in the
coolant flow passage 10 and controls flow (communication) of the
coolant to flow in this coolant flow passage 10. As described
above, the coolant flow passage 10 communicates the coolant between
the internal combustion engine 2 and the heat exchanger 3. The flow
amount control valve 20 is incorporated in series within such
coolant flow passage 10. Therefore, this flow amount control valve
20 is arranged such that the internal combustion engine 2, the flow
amount control valve 20 and the heat exchanger 3 are disposed in
this mentioned order.
[0033] In this embodiment, the flow amount control valve 20 is
configured to include a communication passage 21 and a bypass
passage 22. The communication passage 21 establishes communication
between an inlet port 23 and an outlet port 24. The inlet port 23
is a port trough which the coolant enters (introduced) the flow
amount control valve 20. The outlet port 24 is a port through which
the coolant flows out of (discharged from) the flow amount control
valve 20. Such communication passage 21 corresponds to a main flow
passage of the coolant that communicates through the flow amount
control valve 20.
[0034] On the other hand, the bypass passage 22 establishes
communication between the inlet port 23 and the outlet port 24 with
bypassing the communication passage 21. There, the language
"bypassing the communication passage 21" means that the coolant
does not flow through the communication passage 21. Therefore, the
bypass passage 22 is disposed in juxtaposition with the
communication passage 21, between the inlet port 23 and the outlet
port 24. Such bypass passage 22 corresponds to an auxiliary flow
passage of the coolant that flows in the flow amount control valve
20. The bypass passage 22 is configured such that an opening area
of this bypass passage 22 is smaller than an opening area of the
communication passage 21. For instance, advantageously, the opening
area of the bypass passage 22 can be set to a fraction or one-few
hundreds-th of the opening area of the communication passage 21.
The bypass passage 22 is constituted of an electromagnetic valve 28
whose opened/closed state is controlled by changing a position of a
ball valve 29 in response to an activation signal. Incidentally,
advantageously, the flow amount control valve 20 can be a normally
opened type in view of fail-safe aspect, in order to prevent
blocking of coolant communication in the event of a failure.
[0035] The control section 30 effects control of the opened/closed
state of the flow amount control valve 20. Here, "control of the
opened/closed state of the flow amount control valve 20" means
switchover from the full opened state to the full closed state of
the flow amount control valve 20 as well as switchover from the
full closed state to the full opened state of the flow amount
control valve 20. The control section 30 effects such control based
on a feeding state of a negative pressure produced in the internal
combustion engine 2. Here, "a negative pressure produced in the
internal combustion engine 2" means a pressure lower than the
atmospheric pressure which will develop inside the cylinder when
the piston is lowered during an intake stroke of the internal
combustion engine 2. Then, the control section 30 switches over the
flow amount control valve 20 from the full closed state to the full
opened state based on (in response to) feeding of such negative
pressure, or the control section 30 switches over the flow amount
control valve 20 from the full opened state to the full closed
state based on (in response to) stop of feeding of such negative
pressure.
[0036] The control section 30 is configured to allow feeding of
such negative pressure of the internal combustion engine 2 via the
switching valve 40. This switching valve 40 is configured as a
three-way valve, which switches the pressure to be fed to the
control section 30 to either a first pressure which comprises the
above-described negative pressure produced in the internal
combustion engine 2 or to a second pressure higher than the first
pressure. Here, the first pressure is a pressure that is lower than
the atmospheric pressure and that is produced in the internal
combustion engine 2 as described above. The second pressure is a
pressure higher than the pressure produced in the internal
combustion engine 2. As such "second pressure", the atmospheric
pressure is employed in this embodiment. The first pressure and the
second pressure are fed to a control chamber 31 of the control
section 30.
[0037] The control chamber 31 incorporates therein a spring member
32 and a valve body 33. When the first pressure is fed to the
control chamber 31, the valve body 33 is moved toward a pressure
feed opening 34 side of the control chamber 31 against an urging
force of the spring member 32. In response to this, a link
mechanism 35 is rotated about a rotational axis to rotate a
spherical-faced valve 25 of the flow amount control valve 20 inside
the valve chamber 26. With this, an opening portion 27 of the
communication passage 21 is closed by the spherical-faced valve 25,
thus setting the flow amount control valve 20 into the full closed
state.
[0038] On the other hand, when the second pressure is fed to the
control chamber 31, the valve body 33, as being urged by the spring
member 32, is moved to the far side of the control valve 31. With
this, the link mechanism 35 is rotated about the rotational axis to
rotate the spherical-faced valve 25 of the flow amount control
valve 20 inside the valve chamber 26. With this, the
spherical-faced valve 25 is moved away from the opening portion 27
of the communication passage 21, whereby the flow amount control
valve 20 is set to the full opened state.
[0039] Here, the flow amount control valve 20 can be switched over
from the full closed state to the full opened state only by
stopping feeding of the first pressure. If a period required for
switching the flow amount control valve 20 from the full closed
state to the full opened state by such stopping of feeding of the
first pressure is defined as "first period". In this embodiment,
the control section 30 is configured to require a "second period"
longer than the first period for switching the flow amount control
valve 20 from the full closed state to the full opened state.
Namely, the control section 30 firstly establishes communication of
coolant between the inlet port 23 and the outlet port 24 via the
bypass passage 22 which is the auxiliary passage before
establishing communication of the coolant to the communication
passage 21 which is the main passage and then establishes
communication between the inlet port 23 and the outlet port 24 via
the communication passage 21.
[0040] Therefore, the establishment of communication between the
inlet port 23 and the outlet port 24 via the bypass passage 22
takes longer than the period (first period) required for direct
establishment of communication between the inlet port 23 and the
outlet port 24 via the communication passage 21, by a period
required for the establishment of communication between the inlet
port 23 and the outlet port 24 via the bypass passage 22. With this
arrangement, it is possible to suppress occurrence of inconvenience
of cooling of the internal combustion engine 2 with introduction of
coolant having a lower temperature than the temperature of this
internal combustion engine after warm-up, in spite of this internal
combustion engine 2 being actually warmed up. Incidentally, it is
possible to arrange such that coolant may be communicated also to
the bypass passage 22 or not communicated to this bypass passage
22, when coolant is flowing in the communication passage 21.
[0041] Next, a mode of the flow amount control of coolant by the
cooling system 1 will be explained. FIG. 2 shows an example of the
flow amount control mode. In this FIG. 2, the vertical represents a
flow amount of coolant that flows out of the flow amount control
valve 20 and the horizontal axis represents a time period. As
described above, the flow amount control valve 20 is a normally
opened type. Therefore, this valve 20 is maintained under its full
opened state until the internal combustion engine 2 is started at
t=t1.
[0042] When the internal combustion engine 2 is started at t=t1,
the first pressure as a negative pressure produced in the internal
combustion engine 2 is fed to the control section 30. In response
to this, the flow amount control valve 20 is switched over from the
full opened state to the full closed state (t=t2). At this time,
the thermostat valve 7 too is under its closed state, so no
communication of coolant takes place. Thus, warm-up of the internal
combustion engine 2 is promoted.
[0043] Upon completion of the warm-up of the internal combustion
engine 2 (t=t3), an activation signal is inputted to the
electromagnetic valve 28, thus allowing communication of coolant to
the bypass passage 22. With this, coolant is communicated to the
bypass passage 22. As the coolant is communicated also to the
internal combustion engine 2 under this state, heat will be
equalized over the entire internal combustion engine 2 (t=t3-t4).
Thereafter, in order to effect heat exchange between the coolant
and the heat exchanger 3, the feeding of the first pressure to the
control chamber 31 of the control section 30 is stopped, whereby
the second pressure (e.g. the atmospheric pressure) higher than the
first pressure is fed. In response to this, the flow amount control
valve 20 is shifted to the full opened state (t=t5). Further,
coolant is communicated also to the radiator 4 depending on the
temperature of this coolant, whereby the internal combustion engine
2 is cooled.
[0044] In this way, according to this cooling system 1, when the
flow amount control valve 20 is to be switched over from the full
closed state to the full opened state, during t3-t4, firstly,
coolant is communicated via the bypass passage 22 as the auxiliary
passage by an amount sufficiently smaller than the flow amount of
coolant by the communication passage 21 as a main flow passage;
thereafter, the coolant is communicated via the communication
passage 21. Therefore, in comparison with a period (first period)
required for switchover of the flow amount control valve 20 from
the full closed state to the full opened state, which is the
arrangement of communicating the coolant via the communication
passage 21 alone, the flow amount control valve 20 is switched over
from the full closed state to the full opened state, taking a
longer period (second period).
Other Embodiments
[0045] In the foregoing embodiment, it was explained that the flow
amount control valve 20 includes the communication passage 21 and
the bypass passage 22. Alternatively, the flow amount control valve
20 may not include the bypass passage 22. FIG. 3 is a block diagram
schematically showing such modified configuration of the cooling
system 1.
[0046] In this embodiment, since the bypass passage 22 is not
provided in the flow amount control valve 20, the electromagnetic
valve 28 for controlling communication state of this bypass passage
22 is not provided, either. On the other hand, a constricted
portion 42 is provided in a feed passage 41 through which the
second pressure (e.g. the atmospheric pressure) is fed to the
switching valve 40. This constricted portion 42 constricts the
opening area of the feed passage 41. Such constricted portion 42
can be constituted of a known orifice for example, or can be
constituted of a valve for adjusting the opening area. With this,
the period until the control chamber 31 is filled with fluid having
the atmospheric pressure is set longer than the period until the
control chamber 31 is filled with the atmospheric pressure fluid in
case no such constricted portion 42 is provided in the feed passage
41. Namely, as indicated by t4-t5 in FIG. 4, the period until the
flow amount control valve 20 is switched over from the full closed
state to the full opened state can be extended. Thus, like the
foregoing embodiment, the switchover of the flow amount control
valve 20 from the full closed state to the full opened state can
proceed gradually, so that the heat in the internal combustion
engine 2 can be rendered uniform.
[0047] Further, the control section 30 can be alternatively
configured such that when the flow amount control valve 20 is
switched from the full closed state to the full opened state, the
control section 30 firstly alternates between the full closed state
and a released state of the full closed state and thereafter
switches to the full opened state. With this configuration, as
shown in FIG. 5, during t3-t4, the full closed state and the
released state that allows slight communication of coolant are
alternated (effected for a plurality of times) so as to temporarily
allow a flow amount sufficiently smaller than the flow amount of
coolant under the full opened state, and thereafter the full opened
state is provided, whereby the temperature variation of the
internal combustion engine 2 can be made small like the foregoing
embodiment.
INDUSTRIAL APPLICABILITY
[0048] The present invention can be applied to a cooling system for
an internal combustion engine for controlling flow of coolant
between the internal combustion engine and a heat exchanger.
DESCRIPTION OF REFERENCE MARKS/NUMERALS
[0049] 1: cooling system (cooling system of internal combustion
engine)
[0050] 2: internal combustion engine
[0051] 3: heat exchanger
[0052] 10: coolant flow passage
[0053] 20: flow amount control valve
[0054] 21: communication passage
[0055] 22: bypass passage
[0056] 23: inlet port
[0057] 24: outlet port
[0058] 30: control section
[0059] 40: switching valve
[0060] 41: feed passage
[0061] 42: constricted portion
* * * * *