U.S. patent application number 15/281177 was filed with the patent office on 2017-03-30 for cooling control device.
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 Tatsuya MASUHISA, Kazuyoshi SHIMATANI, Hirotaka WATANABE, Masahiro YOSHIDA.
Application Number | 20170089251 15/281177 |
Document ID | / |
Family ID | 57067951 |
Filed Date | 2017-03-30 |
United States Patent
Application |
20170089251 |
Kind Code |
A1 |
SHIMATANI; Kazuyoshi ; et
al. |
March 30, 2017 |
COOLING CONTROL DEVICE
Abstract
A cooling control device includes: a cooling liquid pump whose
rotational speed is set in accordance with a rotational speed of an
engine; a cooling flow path and a heat exchanger which cool cooling
liquid discharged from the engine; a flow rate control valve which
is provided in the cooling flow path, changes an opening degree by
driving a motor, and adjusts a flow rate of the cooling liquid; and
a control portion which feedback-controls the opening degree of the
flow rate control valve based on a difference between a temperature
of the cooling liquid and a target temperature of the cooling
liquid, and corrects a gain of the feedback control in accordance
with the rotational speed of the engine.
Inventors: |
SHIMATANI; Kazuyoshi;
(Hamamatsu-shi, JP) ; YOSHIDA; Masahiro;
(Toyota-shi, JP) ; WATANABE; Hirotaka; (Anjo-shi,
JP) ; MASUHISA; Tatsuya; (Kariya-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
AISIN SEIKI KABUSHIKI KAISHA |
Kariya-shi |
|
JP |
|
|
Assignee: |
AISIN SEIKI KABUSHIKI
KAISHA
Kariya-shi
JP
|
Family ID: |
57067951 |
Appl. No.: |
15/281177 |
Filed: |
September 30, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F01P 2023/08 20130101;
F01P 2007/146 20130101; F01P 7/167 20130101; F01P 2025/30 20130101;
F01P 2025/64 20130101; F01P 7/14 20130101; F01P 7/164 20130101 |
International
Class: |
F01P 7/16 20060101
F01P007/16; F01P 7/14 20060101 F01P007/14 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 30, 2015 |
JP |
2015-194808 |
Claims
1. A cooling control device comprising: a cooling liquid pump whose
rotational speed is set in accordance with a rotational speed of an
engine; a cooling flow path and a heat exchanger which cool cooling
liquid discharged from the engine; a flow rate control valve which
is provided in the cooling flow path, changes an opening degree by
driving a motor, and adjusts a flow rate of the cooling liquid; and
a control portion which feedback-controls the opening degree of the
flow rate control valve based on a difference between a temperature
of the cooling liquid and a target temperature of the cooling
liquid, and corrects a gain of the feedback control in accordance
with the rotational speed of the engine.
2. The cooling control device according to claim 1, wherein the
gain becomes different in accordance with an opening operation or a
closing operation of the flow rate control valve.
3. The cooling control device according to claim 1, wherein the
gain becomes different in accordance with the opening degree of the
flow rate control valve.
4. The cooling control device according to claim 1, wherein the
cooling liquid pump is a mechanical pump which is driven by the
engine.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is based on and claims priority under 35
U.S.C. .sctn.119 to Japanese Patent Application 2015-194808, filed
on Sep. 30, 2015, the entire contents of which are incorporated
herein by reference.
TECHNICAL FIELD
[0002] This disclosure relates to a cooling control device, more
specifically, to a technology which manages the temperature of an
engine using a cooling liquid.
BACKGROUND DISCUSSION
[0003] JP 2014-156828A (Reference 1) discloses a cooling device of
an engine in which a cooling flow path which circulates cooling
water between the engine and a radiator is formed, and which
interposes a flow rate control valve and a cooling liquid pump in
the cooling flow path. In the cooling device, a control aspect in
which an electronic control unit (ECU) sets a target water
temperature based on operating conditions or driving conditions of
the engine, changes an opening degree of the flow rate control
valve after comparing the target water temperature with an actual
water temperature, and sets an amount of cooling water which flows
to a radiator, is illustrated.
[0004] In the cooling device of Reference 1, considering that a
frictional resistance with respect to a seal member or the like is
received and control responsiveness of the flow rate control valve
deteriorates, an operation amount of feedback control of the flow
rate control valve is corrected. Specifically, the operation amount
is calculated based on the feedback control in an operation amount
calculation portion, it is determined whether the flow rate control
valve is in a normal state where an amount of change is small or in
an excessive state where the amount of change is large in a state
determination portion, and a control amount is corrected when it is
determined that the flow rate control valve is in a normal
state.
[0005] In a cooling device disclosed in JP 2010-190142A (Reference
2), in order to maintain high responsiveness while suppressing
generation of overshoot in flow rate control of a cooling flow
path, an operation amount of a flow rate adjusting unit is
corrected based on a deviation between a target water temperature
and an actual water temperature and a rate of change of the actual
water temperature. For example, since there is a possibility of
overshooting the target temperature in a case where the deviation
is small and the change speed is high, the operation amount may be
decreased.
[0006] In a case where the cooling liquid pump is operated by using
a driving power of the engine, or the like, the rotational speed of
the cooling liquid pump is set in accordance with the rotational
speed of the engine. Therefore, the rotational speed of the cooling
liquid pump increases as the rotational speed of the engine
increases, the flow rate of the cooling flow path increases, and
fluid pressure increases. However, in a case where the flow rate
control valve receives a high fluid pressure, there is a case where
a valve body is pressed to a valve main body and opening and
closing becomes difficult. Therefore, for example, when a control
gain increases, the control responsiveness of the flow rate control
valve becomes excellent when the fluid pressure is high, but when
the fluid pressure is low, the opening degree of the flow rate
control valve substantially varies vertically from the target
opening degree, and hunting is caused. Meanwhile, when the control
gain decreases, it is possible to avoid hunting of the flow rate
control valve when the fluid pressure is low, but the response of
the flow rate control valve becomes slow when the fluid pressure is
high. In this manner, in the cooling device of the engine, there is
a case where the control responsiveness of the flow rate control
valve deteriorates as the fluid pressure of the cooling flow path
varies.
SUMMARY
[0007] Thus, a need exists for a cooling control device which is
not suspectable to the drawback mentioned above.
[0008] A feature of a cooling control device according to an aspect
of this disclosure resides in that the cooling control device
includes: a cooling liquid pump whose rotational speed is set in
accordance with a rotational speed of an engine; a cooling flow
path and a heat exchanger which cool cooling liquid discharged from
the engine; a flow rate control valve which is provided in the
cooling flow path, changes an opening degree by driving a motor,
and adjusts a flow rate of the cooling liquid; and a control
portion which feedback-controls the opening degree of the flow rate
control valve based on a difference between a temperature of the
cooling liquid and a target temperature of the cooling liquid, and
corrects a gain of the feedback control in accordance with the
rotational speed of the engine.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The foregoing and additional features and characteristics of
this disclosure will become more apparent from the following
detailed description considered with the reference to the
accompanying drawings, wherein:
[0010] FIG. 1 is a view illustrating a configuration of a cooling
control device;
[0011] FIG. 2 is a chart illustrating an opening degree of each
valve portion with respect to an operation amount of a valve
body;
[0012] FIG. 3 is a block diagram illustrating a configuration of a
control unit;
[0013] FIG. 4 is a block diagram illustrating a configuration of a
control unit of another embodiment;
[0014] FIG. 5 is a graph illustrating responsiveness of a flow rate
control valve of each control gain;
[0015] FIG. 6 is a view illustrating a state where the valve body
having a high opening degree receives fluid pressure;
[0016] FIG. 7 is a view illustrating a state where the valve body
having a low opening degree receives fluid pressure;
[0017] FIG. 8 is a view illustrating a state where the valve body
receives the fluid pressure in a case where the flow direction of
the flow body has changed;
[0018] FIG. 9 is a view illustrating a state where the valve body
having a low opening degree of another embodiment receives fluid
pressure; and
[0019] FIG. 10 is a view illustrating a state where the valve body
having a high opening degree of another embodiment receives fluid
pressure.
DETAILED DESCRIPTION
[0020] Hereinafter, the embodiment of the disclosure will be
described based on the drawings.
Configuration of Base Body
[0021] As illustrated in FIG. 1, a cooling control device which is
provided with a water pump WP (an example of a cooling liquid pump)
which sends cooling water (an example of cooling liquid) of an
engine E that serves as an internal combustion engine; a plurality
of flow paths F which are formed to be aligned; heat exchangers
which are provided in each of the plurality of flow paths F; a
cooling circuit which controls a flow of the cooling water (an
example of the cooling liquid) and is configured of a flow rate
control valve V; and a control unit (an example of a control
portion) 10 which sets an opening degree of the flow rate control
valve V.
[0022] In the cooling control device, a water temperature of the
cooling water (cooling liquid) is detected by a water temperature
sensor S (an example of a liquid temperature sensor), the control
unit 10 controls the flow rate control valve V based on the
detection result, and thus, the heat exchange is managed by the
heat exchanger.
[0023] As the heat exchanger, an EGR cooler 1, an oil cooler 2, and
a radiator 3 which will be described later are provided in the
corresponding flow path F. In addition, the water pump WP is
disposed in a return flow path FR (a part of the flow path F)
between the flow rate control valve V and the engine E.
[0024] The cooling control device is configured to manage the
temperature of the engine E (internal combustion engine) of a
vehicle, such as a passenger car. The engine E has a water jacket
which is formed in a region across a cylinder head from a cylinder
block. The cooling control device sends out the cooling water of
the water jacket to the flow path F, and allows the cooling water
to return to the water jacket by the water pump WP after supplying
the cooling water to the heat exchanger and performing the heat
exchange. In addition, the engine E transmits a driving power from
a crank shaft which serves as an output shaft to a transmission.
Furthermore, the engine E can be used generally in the internal
combustion engine not being limited to a reciprocating engine. In
addition, not being limited to a configuration in which the driving
power directly acts on the transmission, for example, the engine E
may transmit the driving power to an electric motor similar to a
hybrid type vehicle.
Flow Path and Heat Exchanger
[0025] The water temperature sensor S is provided in the engine E,
and the plurality of flow paths F through which the cooling water
discharged from the engine E is sent and which branches from a main
flow path FM, are formed. As the plurality of flow paths F (an
example of a cooling flow path), a first flow path F1, a second
flow path F2, and a third flow path F3, are formed. As the heat
exchanger, the EGR cooler 1 is provided in the first flow path F1,
the oil cooler 2 is provided in the second flow path F2, and the
radiator 3 is provided in the third flow path F3.
[0026] A technology which takes out a part of exhaust gas of the
engine E, improves components in the exhaust gas by returning the
exhaust gas to an induction system, or improves fuel efficiency, is
referred to as exhaust gas recirculation (EGR), and the EGR cooler
1 performs the heat exchange (cooling) with respect to a part of
the exhaust gas taken out of the engine E by the cooling water.
[0027] The oil cooler 2 has a configuration in which lubricating
oil stored in an oil pan 5 of the engine E is supplied by an oil
pump 6, and performs the heat exchange between the lubricating oil
and the cooling water. The lubricating oil to which the heat
exchange is performed by the oil cooler 2 is supplied to a
hydraulic operating device, such as a valve opening and closing
timing control device, or to a lubricating part of each portion of
the engine. The oil pump 6 is a variable hydraulic mechanical oil
pump which can control a liquid pressure level by 2 steps or more,
and is driven by the engine E.
[0028] The radiator 3 has a function of managing the temperature of
the engine E by releasing the heat of the cooling water, and
cooling wind is supplied by a radiator fan 7. The radiator fan 7 is
driven by a fan motor 7M configured of an electric motor.
Flow Rate Control Valve
[0029] The flow rate control valve V is configured to be a rotary
operating type in which a valve body is freely rotatably
accommodated on the inside of a valve case. In addition, a valve
motor VM (an example of a motor) which is configured of an electric
motor to perform a rotation operation with respect to the valve
body, and a valve sensor VS (an example of an opening degree
sensor) which detects a rotation angle of the valve body.
Furthermore, the flow rate control valve V may also use a sliding
operation type in which the valve body that performs a sliding
operation is accommodated on the inside of the valve case.
[0030] The flow rate control valve V includes a first valve portion
V1 which opens and closes the first flow path F1, a second valve
portion V2 which opens and closes the second flow path F2, and a
third valve portion V3 which opens and closes the third flow path
F3. The opening degree in the first valve portion V1, the second
valve portion V2, and the third valve portion V3 with respect to an
operation amount of the valve body by the flow rate control valve V
having this configuration, is illustrated in FIG. 2. Furthermore,
the first valve portion V1, the second valve portion V2, and the
third valve portion V3 are generally referred to as a valve
portion.
[0031] In FIG. 2, a longitudinal axis illustrates the opening
degree of the first valve portion V1, the second valve portion V2,
and the third valve portion V3 (the opening degree is illustrated
by a percentage), and a horizontal axis illustrates the operation
amount (rotation amount) of the valve body. As can be ascertained
from the drawing, in a case where the valve body is at an initial
position, a fully closed mode M0 in which the first valve portion
V1, the second valve portion V2, and the third valve portion V3 are
in a closed state is achieved, and the cooling water does not flow
to the first flow path F1, the second flow path F2, and the third
flow path F3.
[0032] Next, by operating the valve body from the fully closed mode
M0 in the opening direction, in a state where the second valve
portion V2 and the third valve portion V3 are maintained in a
closed state, a first supply mode M1 in which the opening degree of
the first valve portion V1 can be adjusted, is achieved.
[0033] Furthermore, by operating the valve body from the first
supply mode M1 in the opening direction exceeding a fully opened
state, in a state where the opening degree of the first valve
portion V1 is maintained to be fully opened (the third valve
portion V3 is maintained in a closed state), a second supply mode
M2 in which the opening degree of the second valve portion V2 can
be adjusted, is achieved.
[0034] In addition, by operating the valve body from the second
supply mode M2 in the opening direction exceeding a fully opened
state, in a state where the opening degree of the first valve
portion V1 and the opening degree of the second valve portion V2
are maintained to be fully opened, a third supply mode M3 in which
the opening degree of the third valve portion V3 can be adjusted,
is achieved.
[0035] In particular, in the flow rate control valve V, the supply
of the cooling water is not performed in the second valve portion
V2 before the opening degree of the first valve portion V1 reaches
the fully opened state. Similar to this, the supply of the cooling
water is not performed in the third valve portion V3 before the
opening degree of the second valve portion V2 reaches the fully
opened state. Furthermore, not being limited to this configuration,
for example, the flow rate control valve V may be provided with
four or more valve portions, or may perform the opening operation
at the same time in association with the opening degrees of the
plurality of valve portions.
Control Unit
[0036] The control unit 10 illustrated in FIG. 3 manages the entire
engine, controls a water amount of the cooling water which flows to
the flow path F by the flow rate control valve V when operating the
engine E, and manages an amount of heat exchanged by the heat
exchanger. In particular, in a case where the temperature of the
engine E is managed, it is possible to appropriately set the flow
rate of the cooling water supplied to the radiator 3 by the control
of the flow rate control valve V.
[0037] In the control unit 10, a target flow rate is set based on a
difference between the temperature of the cooling water detected by
the water temperature sensor S and the target temperature, and a
target valve opening degree of the flow rate control valve V is set
in accordance with the rotational speed (the rotational speed per
unit time) of the engine E to obtain the target flow rate.
[0038] As illustrated in FIG. 3, signals from the water temperature
sensor S (liquid temperature sensor), a revolution number sensor
21, and the valve sensor VS (opening degree sensor) are input to
the control unit 10. In addition, the control unit 10 outputs a
control signal to the valve motor VM which controls the opening
degree of the flow rate control valve V.
[0039] The water temperature sensor S is provided in the engine E
so as to detect the water temperature of the cooling water, and is
configured of a thermistor or the like. The revolution number
sensor 21 is configured of a non-contact type sensor which measures
the rotational speed of the crank shaft of the engine E, and can
detect the rotational speed (the rotational speed per unit time) of
the crank shaft from the detection of the revolution number sensor
21.
[0040] The valve sensor VS is configured of a hall IC or a
potentiometer, and detects the rotation angle of the valve body of
the flow rate control valve V. By the detection, it is possible to
detect the opening degree of the valve portion of each supply mode
in the flow rate control valve V.
[0041] The control unit 10 is provided with a central processing
unit (CPU), a digital signal processor (DSP), an application
specific integrated circuit (ASIC), or the like. In addition, in
the control unit 10, as necessary, a load correction gain 11, an
opening and closing direction correction item 12, and a valve
opening degree correction item 13 which are calculated by software,
are used.
[0042] In the control unit 10, a supply mode is selected from any
of the first supply mode M1, the second supply mode M2, and the
third supply mode M3 based on the detection result of the water
temperature sensor S. In the first supply mode M1 and the second
supply mode M2, the opening degree of the first valve portion V1
and the second valve portion V2 is set based on the detection
result of the water temperature sensor S, and the management of the
water amount of the cooling water which is supplied to the EGR
cooler 1 and the oil cooler 2 is controlled.
[0043] In the third supply mode M3, the target flow rate of the
cooling water which is supplied to the radiator 3 by the third flow
path F3 is set, the target opening degree of the flow rate control
valve V is set based on the rotational speed of the engine E, and
the driving of the valve motor VM is controlled to obtain the
target opening degree. Furthermore, in the third supply mode M3,
the travelling is performed at a low speed, and by the driving of
the fan motor 7M when the water temperature is high, the radiator
fan 7 is driven, and the cooling wind is supplied to the radiator
3. However, the fan motor 7M is not driven when travelling is
performed at a high speed.
[0044] A control state in the third supply mode M3 will be
described hereinafter.
[0045] In the control unit 10, the opening degree of the third
valve portion V3 (flow rate control valve V) changes, the flow rate
of the third flow path F3 is controlled, and the temperature of the
engine E is controlled. The control signal is output to the valve
motor VM from the control unit 10. The control unit 10 has a PWM
circuit which performs PWM control, changes a duty ratio of a pulse
width based on a corrected control gain, and controls the valve
motor VM. Accordingly, it is possible to easily and rapidly operate
the third valve portion V3.
[0046] The target opening degree of the third valve portion V3 is
calculated based on the target flow rate of the third flow path F3.
The control gain when feedback-controlling the opening degree of
the third valve portion V3 is calculated based on a difference
between the target opening degree and the actual opening
degree.
[0047] Meanwhile, in accordance with the rotational speed of the
engine, the load correction gain 11 is calculated in the feedback
control of the third valve portion V3. Furthermore, the load
correction gain 11 is corrected based on the opening and closing
direction correction item 12 and the valve opening degree
correction item 13. The opening and closing direction correction
item 12 is a parameter which corrects the control gain in
accordance with the opening operation or the closing operation of
the third valve portion V3. The valve opening degree correction
item 13 is a parameter which corrects the control gain in
accordance with the opening degree of the third valve portion V3.
The control amount and the load correction gain are multiplied
based on the actual valve opening degree and the target valve
opening degree, the final control gain is obtained, and the control
signal is output to the valve motor VM based on the control
gain.
[0048] The control unit 10 may be a control aspect which is
different from the configuration illustrated in FIG. 3. For
example, in the example illustrated in FIG. 4, the load correction
gain 11 calculated in accordance with the rotational speed of the
engine is multiplied by the control gain based on the actual valve
opening degree and the target valve opening degree, and the control
gain corrected based on the rotational speed of the engine is
obtained. After this, by adding the opening and closing direction
correction item 12 and the valve opening degree correction item 13
to the control gain, the final control gain is obtained.
[0049] In FIG. 5, a relationship between the rotational speed of
the engine and the fluid pressure (water pressure), and
responsiveness of each gain of the feedback control of the opening
degree of the third valve portion V3, is illustrated. The
rotational speed of the water pump WP is set in accordance with the
rotational speed of the engine E. Therefore, when the rotational
speed of the engine E is low, the rotational speed of the water
pump WP also decreases, and the fluid pressure received by the
third valve portion V3 is in a low state. Meanwhile, since the
rotational speed of the water pump WP also increases when the
rotational speed of the engine E increases, the fluid pressure
received by the third valve portion V3 also increases.
[0050] Under the condition, when the gain which is appropriate for
high water pressure is set, when the fluid pressure is high,
appropriate responsiveness is ensured. However, when the rotational
speed of the engine is low and the fluid pressure is low, the valve
opening degree substantially varies vertically from the target
opening degree, and hunting is caused. Meanwhile, when the gain
which is appropriate for low water pressure is set, appropriate
responsiveness is ensured when the fluid pressure is low. However,
when the rotational speed of the engine increases and the fluid
pressure is high, the time period until the valve opening degree
becomes the target opening degree becomes longer, and the
responsiveness of the feedback control of the valve opening degree
deteriorates.
[0051] Meanwhile, in the control unit 10 of the embodiment, the
gain of the feedback control is corrected by the load correction
gain 11 which is calculated in accordance with the rotational speed
of the engine. For example, the negative load correction gain 11
which is appropriate for low fluid pressure is set when the
rotational speed of the engine is low, and the load correction gain
11 which is appropriate for high fluid pressure is set when the
rotational speed of the engine is high. Accordingly, it is possible
to suppress the hunting or the delay of the responsiveness in the
third valve portion V3. As a result, it is possible to stably
perform the temperature control of the cooling liquid, and to
maintain the temperature of the engine within an appropriate
range.
[0052] The opening and closing direction correction item 12 is a
parameter which corrects the control gain in accordance with the
opening and closing direction of the third valve portion V3, that
is, the opening operation or the closing operation. A relationship
between the opening operation or the closing operation in the
operation direction of the third valve portion V3, and the fluid
pressure, will be described. In the third valve portion V3, an
inflow portion 15 on an upstream side of a valve body 32, a
communication portion 16 which is formed every time the valve body
32 is open, and an outflow portion 17 on a downstream side of the
valve body 32, are provided. In a rotary valve, in a case where the
opening operation is performed with respect to the valve body 32 to
achieve a state of FIG. 7 from a state of FIG. 6, the flow rate of
the communication portion 16 increases, and the fluid pressure of
the inflow portion 15 of the valve body 32 decreases. In addition,
in the valve body 32, an open end surface 32a is pressed to the
opening operation side by the fluid pressure, the resistance force
of the opening operation is reduced.
[0053] Meanwhile, in a case where the closing operation is
performed with respect to the valve body 32 to achieve a state of
FIG. 6 from a state of FIG. 7, the flow rate of the communication
portion 16 decreases, and the fluid pressure of the inflow portion
15 increases. In addition, since high fluid pressure acts on the
open end surface 32a in the communication portion 16, the
resistance force when the closing operation of the valve body 32
increases. In this manner, in a case where the resistance force is
large when the closing operation is performed among the opening
operation and the closing operation of the valve body 32, a
parameter in which the control gain when the closing operation is
performed becomes greater than the control gain when the opening
operation is performed, is set as the opening and closing direction
correction item 12.
[0054] The valve opening degree correction item 13 is a parameter
which corrects the control gain in accordance with the opening
degree of the third valve portion V3. A relationship between the
opening degree of the third valve portion V3 and the fluid pressure
will be described. For example, in the rotary valve, as illustrated
in FIG. 6, when the valve body 32 has a low opening degree, the
fluid pressure of the inflow portion 15 increases. Therefore, in a
case where the opening operation or the closing operation is
performed with respect to the valve body 32 from a state of FIG. 6
in which the opening degree is low, the frictional force becomes
the resistance force as the valve body 32 is pressed to a valve
main body 33.
[0055] Meanwhile, as illustrated in FIG. 7, when the valve body 32
has a high opening degree, compared to a case of FIG. 6 where the
opening degree is low, the fluid pressure of the inflow portion 15
is lower. Therefore, in a case where the valve body 32 has a high
opening degree, compared to a case where the opening degree is
lower, the resistance force which is generated based on the fluid
pressure of the inflow portion 15 is small. In this manner, in a
case where the resistance force decreases as the opening degree of
the valve body 32 increases, a parameter in which the control gain
decreases as the opening degree of the third valve portion V3
increases, is set as the valve opening degree correction item
13.
Modification Example of First Embodiment
[0056] In the embodiment, the cooling liquid flows in the
orientation opposite to that of the first embodiment with respect
to the third valve portion V3. As illustrated in FIG. 8, the
arc-like valve body 32 is provided in the outflow portion 17, and
the cooling water flows toward the outflow portion 17 from the
inflow portion 15. In this case, since the fluid pressure of the
inflow portion 15 presses an outer circumferential surface of the
arc-like valve body 32, the size or the direction of the fluid
pressure received by the valve body 32 becomes different from that
of the first embodiment. For example, there is a case where the
fluid pressure of the inflow portion 15 acts on the valve body 32
to promote the opening operation. Therefore, in the embodiment,
correction of the control gain which is different from that of the
first embodiment is performed, for example, the control gain is
further reduced when the opening operation of the third valve
portion V3 is performed.
Second Embodiment
[0057] In the embodiment, the gate type valve body 32 which is
directly operated by the third valve portion V3 (flow rate control
valve V), is provided. In this case, as illustrated in FIG. 9, the
fluid pressure of the inflow portion 15 acts to hold the valve body
32, and the flow of the fluid of the communication portion 16 also
acts on the open end surface 32a of the valve body 32. Here, when
the opening operation is performed with respect to the valve body
32 as illustrated in FIG. 10, the flow rate of the communication
portion 16 increases, and the fluid pressure of the inflow portion
15 deteriorates. Therefore, when the opening operation is performed
with respect to the third valve portion V3, the resistance force
received by the valve body 32 tends to decrease.
[0058] Meanwhile, in a case where the closing operation is
performed with respect to the valve body 32 to achieve a state of
FIG. 9 from a state of FIG. 10, the flow rate of the communication
portion 16 decreases, and the fluid pressure of the inflow portion
15 increases. Therefore, when the closing operation is performed
with respect to the third valve portion V3, the resistance force
received by the valve body 32 tends to increase. Therefore, even in
the valve body 32, a parameter in which the control gain when the
closing operation is performed becomes greater than the control
gain when the opening operation is performed with respect to the
third valve portion V3, is set as the opening and closing direction
correction item 12.
[0059] In the relationship between the opening degree of the third
valve portion V3 and the fluid pressure, as illustrated in FIG. 9,
the fluid pressure of the inflow portion 15 increases when the
valve body 32 has a low opening degree. Therefore, in a case where
the opening operation or the closing operation is performed with
respect to the valve body 32 from a state of FIG. 9 where the
opening degree is low, the frictional force becomes the resistance
force as the valve body 32 is pressed to the valve main body 33.
Meanwhile, as illustrated in FIG. 10, when the valve body 32 has a
high opening degree, compared to a case of FIG. 9 where the opening
degree is low, the fluid pressure of the inflow portion 15 is
lower. Therefore, in a case where the valve body 32 has a high
opening degree, compared to a case where the opening degree is low,
the resistance force which is generated based on the fluid pressure
of the inflow portion 15, is smaller.
Other Embodiments
[0060] (1) In the above-described embodiment, an example in which
the gain when feedback-controlling the third valve portion V3 in
the third supply mode M3 is corrected by the control unit 10, is
described, but similarly, the gain when feedback-controlling the
first valve portion V1 in the first supply mode M1 or the second
valve portion V2 in the second supply mode M2, may be
corrected.
[0061] (2) In the above-described embodiment, an example in which
the correction is performed so that the gain when
feedback-controlling the flow rate control valve V increases as the
rotational speed of the engine increases, in the control unit 10,
is described, but in a case where the resistance force received by
the flow rate control valve V deteriorates as the rotational speed
of the engine increases, the correction is performed so that the
gain decreases.
[0062] (3) In the above-described embodiment, an example in which
the parameter in which the control gain when the closing operation
of the flow rate control valve V is performed becomes greater than
the control gain when the opening operation is performed, is set as
the opening and closing direction correction item 12, is described,
but in a case where the resistance force when the opening operation
is performed among the opening operation and the closing operation
is large, a parameter in which the control gain when the opening
operation is performed is greater than the control gain when the
closing operation of the flow rate control valve V is performed, is
set as the opening and closing direction correction item 12.
[0063] (4) In the above-described embodiment, an example in which
the parameter in which the control gain decreases as the opening
degree of the flow rate control valve V increases, is set as the
valve opening degree correction item 13, is described, but in a
case where the resistance force received by the valve body 32 when
the opening degree is high, is greater than the resistance force
when the opening degree is low, a parameter in which the control
gain increases as the opening degree of the flow rate control valve
V increases, is set as the valve opening degree correction item
13.
[0064] (5) In the above-described embodiment, an example in which
the water pump WP is a mechanical pump which is driven by the
engine E, is described, but the water pump WP may be an electric
pump. Even when the water pump WP is an electric pump, it is
possible to set the rotational speed of the pump in accordance with
the rotational speed of the engine E. In a case where the electric
pump is used as the water pump WP, the gain of the feedback control
may be corrected in accordance with the rotational speed of the
pump in the control unit 10. In addition, instead of changing the
gain of the feedback control, by making the rotational speed of the
water pump WP constant, appropriate responsiveness may be ensured
in the feedback control of the flow rate control valve V.
[0065] (6) In the above-described embodiment, an example in which
the valve body 32 of the flow rate control valve V is formed in a
shape of an arc and in a shape of a plate, is described, but the
valve body 32 may have other shapes, such as a shape of a spherical
body or a circle.
[0066] A feature of a cooling control device according to an aspect
of this disclosure resides in that the cooling control device
includes: a cooling liquid pump whose rotational speed is set in
accordance with a rotational speed of an engine; a cooling flow
path and a heat exchanger which cool cooling liquid discharged from
the engine; a flow rate control valve which is provided in the
cooling flow path, changes an opening degree by driving a motor,
and adjusts a flow rate of the cooling liquid; and a control
portion which feedback-controls the opening degree of the flow rate
control valve based on a difference between a temperature of the
cooling liquid and a target temperature of the cooling liquid, and
corrects a gain of the feedback control in accordance with the
rotational speed of the engine.
[0067] According to this configuration, the cooling liquid pump
whose rotational speed is set in accordance with the rotational
speed of the engine, is provided. Therefore, the rotational speed
of the cooling liquid pump increases as the rotational speed of the
engine increases. According to a change in the rotational speed of
the cooling liquid pump, the fluid pressure of the cooling flow
path increases and decreases. When the fluid pressure of the
cooling flow path increases, there is a case where a valve body of
the flow rate control valve is held by the fluid pressure and the
opening and closing becomes difficult. Here, in the configuration,
the gain of the feedback control is corrected in accordance with
the rotational speed of the engine. For example, when the
rotational speed of the engine is low and the fluid pressure is
low, the correction of lowering the gain of the feedback control is
performed, and when the rotational speed of the engine is high and
the fluid pressure is high, the correction of increasing the gain
of the feedback control is performed. Accordingly, it is possible
to suppress hunting or delay of responsiveness in the flow rate
control valve. As a result, it is possible to stably perform
temperature control of the cooling liquid, and to maintain the
temperature of the engine to be within an appropriate range.
[0068] In addition, in the flow rate control valve, there is also a
case where the fluid pressure acts as a propulsive force with
respect to the opening and closing operation without becoming a
resistance force. In this case, the correction may be performed for
decreasing the gain as the rotational speed of the engine
increases.
[0069] Another feature of the cooling control device according to
this disclosure resides in that the gain becomes different in
accordance with an opening operation or a closing operation of the
flow rate control valve.
[0070] In the flow rate control valve, the acting fluid pressure
also becomes different according to the operation direction of the
opening operation or the closing operation. In a case where the
opening operation is performed with respect to the flow rate
control valve, a flow rate of a communication portion which is an
open region of the flow rate control valve increases, and the fluid
pressure of an inflow portion which is on an upstream side of the
valve body deteriorates. Therefore, the resistance force when the
opening operation is performed decreases. Meanwhile, in a case
where the closing operation is performed, the flow rate of the
communication portion decreases, and the fluid pressure of the
inflow portion increases. Therefore, the resistance force when the
closing operation is performed increases. Here, in this
configuration, the gain becomes different in accordance with the
opening operation or the closing operation of the flow rate control
valve. In the above-described example, the correction is performed
so that the gain when the closing operation is performed becomes
greater than the gain when the opening operation is performed.
Accordingly, it is possible to appropriately set the gain of the
feedback control when the opening operation and the closing
operation are performed with respect to the flow rate control
valve, and to suppress variation of the control responsiveness of
the flow rate control valve.
[0071] Another feature of the cooling control device according to
this disclosure resides in that the gain becomes different in
accordance with the opening degree of the flow rate control
valve.
[0072] In the flow rate control valve, the acting fluid pressure
also becomes different according to the opening degree. When the
flow rate control valve has a low opening degree, the fluid
pressure of the inflow portion of the flow rate control valve
increases. At this time, since the valve body of the flow rate
control valve is pressed to the valve main body, the frictional
force with respect to the valve main body becomes the resistance
force when the opening operation or the closing operation is
performed with respect to the valve body. Meanwhile, when the flow
rate control valve has a high opening degree, compared to the lower
opening degree, the fluid pressure of the inflow portion is lower.
Therefore, in the flow rate control valve having a high opening
degree, the resistance force generated based on the fluid pressure
of the inflow portion is smaller than that in the flow rate control
valve having a low opening degree. In this manner, since the
resistance force becomes different when the flow rate control valve
is operated according to the opening degree, in this configuration,
the gain becomes different in accordance with the opening degree of
the flow rate control valve. Similar to the above-described case,
in a case where the resistance force decreases as the opening
degree of the flow rate control valve increases, the correction is
performed so that the gain decreases as the opening degree of the
flow rate control valve increases. Accordingly, it is possible to
appropriately set the gain of the feedback control of the flow rate
control valve even in different opening degrees, and to suppress
variation of the control responsiveness of the flow rate control
valve.
[0073] Another feature of the cooling control device according to
this disclosure resides in that the cooling liquid pump is a
mechanical pump which is driven by the engine.
[0074] Similar to this configuration, when the cooling liquid pump
is a mechanical pump which is driven by the engine, the rotational
speed of the cooling liquid pump is linked with the rotational
speed of the engine. Therefore, it is not possible to arbitrarily
change the rotational speed of the cooling liquid pump. However, as
the gain of the feedback control of the flow rate control valve is
corrected in accordance with the rotational speed of the engine, it
is possible to appropriately control the temperature of the engine
even when the cooling liquid pump is an inexpensive mechanical
pump.
[0075] This disclosure can be used in a cooling control device
which manages the temperature of the engine by circulating the
cooling liquid.
[0076] The principles, preferred embodiment and mode of operation
of the present invention have been described in the foregoing
specification. However, the invention which is intended to be
protected is not to be construed as limited to the particular
embodiments disclosed. Further, the embodiments described herein
are to be regarded as illustrative rather than restrictive.
Variations and changes may be made by others, and equivalents
employed, without departing from the spirit of the present
invention. Accordingly, it is expressly intended that all such
variations, changes and equivalents which fall within the spirit
and scope of the present invention as defined in the claims, be
embraced thereby.
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