U.S. patent application number 12/952884 was filed with the patent office on 2011-10-06 for apparatus for controlling electric water pump of hybrid vehicle and method thereof.
This patent application is currently assigned to HYUNDAI MOTOR COMPANY. Invention is credited to Jae Young Choi, Seok Joon Kim, Jae Heon Lee, Byungsoon Min, Hyungseuk Ohn.
Application Number | 20110246007 12/952884 |
Document ID | / |
Family ID | 44694970 |
Filed Date | 2011-10-06 |
United States Patent
Application |
20110246007 |
Kind Code |
A1 |
Choi; Jae Young ; et
al. |
October 6, 2011 |
APPARATUS FOR CONTROLLING ELECTRIC WATER PUMP OF HYBRID VEHICLE AND
METHOD THEREOF
Abstract
The present invention relates to a water pump control apparatus
of a hybrid vehicle and a control method thereof. An exemplary
apparatus according to the present invention includes a thermostat
determining a circulation path of the coolant, a coolant
temperature sensor, a motorized water pump configured to pump a
coolant, and a control portion for controlling the motorized water
pump to circulate the coolant, if the hybrid vehicle enters into an
EV mode or an idle engine stop mode if the coolant temperature
exceeds a predetermined temperature. An exemplary method of the
present invention includes the steps of suspending operation of the
motorized water pump if the coolant temperature is less than a
predetermined value until a cooling fan is operated, and
controlling a driving speed of the motorized water pump according
to a load of the cooling fan in operation.
Inventors: |
Choi; Jae Young; (Seoul,
KR) ; Ohn; Hyungseuk; (Hwaseong, KR) ; Min;
Byungsoon; (Seongnam, KR) ; Kim; Seok Joon;
(Yongin, KR) ; Lee; Jae Heon; (Hwaseong,
KR) |
Assignee: |
HYUNDAI MOTOR COMPANY
Seoul
KR
KIA MOTORS CORPORATION
Seoul
KR
|
Family ID: |
44694970 |
Appl. No.: |
12/952884 |
Filed: |
November 23, 2010 |
Current U.S.
Class: |
701/22 ;
903/904 |
Current CPC
Class: |
F01P 7/04 20130101; F01P
7/16 20130101; B60W 10/30 20130101; F01P 7/162 20130101; F01P
2025/66 20130101; B60W 20/00 20130101; F01P 7/08 20130101; F01P
2025/12 20130101; F01P 7/164 20130101; F01P 2025/60 20130101; F01P
5/14 20130101; B60H 1/00885 20130101 |
Class at
Publication: |
701/22 ;
903/904 |
International
Class: |
F01P 5/12 20060101
F01P005/12 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 30, 2010 |
KR |
10-2010-0028562 |
Apr 29, 2010 |
KR |
10-2010-0040328 |
Claims
1. A motorized water pump control apparatus of a hybrid vehicle,
comprising: a thermostat determining a circulation path of a
coolant; a coolant temperature sensor detecting a coolant
temperature; a motorized water pump configured to pump the coolant;
and a control portion for controlling the motorized water pump to
circulate the coolant, if the vehicle enters into an EV mode or an
idle engine stop mode in a condition that the coolant temperature
exceeds a predetermined temperature value.
2. The motorized water pump control apparatus of claim 1, wherein
the control portion drives the motorized water pump, if an
operation of a heating apparatus is demanded, in the EV mode or the
idle engine stop mode.
3. The motorized water pump control apparatus of claim 1, wherein
the control portion varies a driving speed of the motorized water
pump according to a vehicle speed, if the vehicle enters into the
idle engine stop mode in a condition that the coolant temperature
exceeds the predetermined temperature value.
4. The motorized water pump control apparatus of claim 1, wherein
the control portion enters into a limp home mode, outputs an alarm
message, and drives the motorized water pump to circulate the
coolant if an error is detected.
5. A motorized water pump control method of a vehicle, comprising:
determining whether a vehicle enters into an EV mode or an idle
engine stop mode; determining whether a coolant temperature exceeds
a predetermined value if the vehicle is in the EV mode or the idle
engine stop mode; driving a motorized water pump if the coolant
temperature exceeds the predetermined temperature value; turning
off the motorized water pump if the coolant temperature is less
than the predetermined temperature value; and varying a driving
speed of the motorized water pump according to a vehicle speed if
the vehicle speed is larger than a predetermined vehicle speed
value when the motorized water pump is in operation.
6. The motorized water pump control method of claim 5, wherein the
motorized water pump is driven to circulate the coolant if
operation of a heating apparatus is demanded in the EV mode or the
idle engine stop mode.
7. A motorized water pump control apparatus of a hybrid vehicle,
comprising: a thermostat determining a circulation path of coolant
according to a coolant temperature exhausted from an engine; a
radiator emitting heat absorbed in the coolant; a cooling fan
disposed at one side of the radiator to blow air; a motorized water
pump disposed between the engine and the thermostat to circulate
the coolant; and a control portion that varies an on or off mode of
the motorized water pump according to an operating load of the
cooling fan.
8. The motorized water pump control apparatus of claim 7, wherein
the control portion monitors data relating to environmental and
driving conditions of the engine and enters into a limp home mode
so as to operate the motorized water pump if an error is detected
from the monitored data.
9. The motorized water pump control apparatus of claim 7, wherein
the control portion stops operation of the motorized water pump
until the cooling fan is operated a first time after ignition, if
the coolant temperature is lower than a predetermined temperature
value.
10. The motorized water pump control apparatus of claim 7, wherein
the control portion drives the motorized water pump at a second
speed if the cooling fan is operated at a low speed.
11. The motorized water pump control apparatus of claim 10, wherein
the control portion drives the motorized water pump at a first
speed that is slower than the second speed if the cooling fan is
turned off.
12. The motorized water pump control apparatus of claim 7, wherein
the control portion drives the motorized water pump at a third
speed that is faster than the second speed if the cooling fan is
driven at a high speed.
13. The motorized water pump control apparatus of claim 12, wherein
the control portion increases the driving speed of the motorized
water pump according to a factor value of a vehicle speed if the
vehicle speed exceeds a predetermined vehicle speed value.
14. A motorized water pump control method of a hybrid vehicle,
comprising: suspending operation of a motorized water pump in a
condition in which a coolant temperature is less than a
predetermined temperature value until a cooling fan is operated;
and controlling a driving speed of the motorized water pump
according to a load of a cooling fan while the cooling fan is being
operated.
15. The motorized water pump control method of claim 14, wherein
the motorized water pump is driven at a second speed while the
cooling fan is being driven at a low speed.
16. The motorized water pump control method of claim 15, wherein
the motorized water pump is driven at a first speed that is slower
than the second speed while the cooling fan is halted.
17. The motorized water pump control method of claim 15, wherein
the motorized water pump is driven at a third speed that is faster
than the second speed if it is determined that the cooling fan is
being operated at a high speed, and it is determined that the
engine is in a high load condition based on a determined value of a
coolant flux.
18. The motorized water pump control method of claim 17, wherein a
factor value according to the vehicle speed is applied to drive the
motorized water pump faster than the third speed if the cooling fan
is driven at a high speed, the vehicle speed exceeds a
predetermined value, and it is determined that the engine is in a
high speed and high load condition.
19. The motorized water pump control method of claim 14, wherein
the driving speed of the motorized water pump is varied
proportionally according to the vehicle speed in the high speed or
high load condition of the engine.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to and the benefit of
Korean Patent Application No. 10-2010-0028562 and 10-2010-0040328
filed in the Korean Intellectual Property Office on Mar. 30 and
Apr. 29, 2010, the entire contents of which are incorporated herein
by reference.
BACKGROUND OF THE INVENTION
[0002] (a) Field of the Invention
[0003] The present invention relates to a motorized water pump
applied to a vehicle, in particular a hybrid vehicle.
[0004] (b) Description of the Related Art
[0005] Hybrid vehicles have been developed and are increasingly
mass produced to be sold and driven by consumers. There are various
kinds of hybrid vehicles. A typical hybrid vehicle generally
includes an engine and a motor. When the hybrid vehicle is in
electric vehicle mode (EV mode), only the motor is operated.
Alternatively, when the hybrid vehicle is in hybrid vehicle mode
(HV mode), both the motor and the engine are in operation.
[0006] A hybrid vehicle typically generates electricity through
regenerative braking which charges the battery, and reduces fuel
consumption and exhaust gas through an ISG (idle stop and go)
system. The hybrid vehicle forcibly circulates a coolant so as to
prevent the engine from being overheated. Accordingly, if the
hybrid vehicle enters into the EV mode or the ISG mode in a
condition that the coolant temperature is high, the water pump
operated by the engine stops operating such that the coolant is not
circulated. The engine is repeatedly re-started with a high
temperature coolant because of the idle engine stop mode and the HV
mode, as a result, if the load of the engine is rapidly raised
after restarting the engine, the coolant can be overheated.
[0007] If a user requests use of a heating system during the EV
mode or the idle engine stop mode, a problematic situation may
arise where the hot coolant does not circulate through the heating
system. In addition, the EV mode and the idle engine stop mode
cannot be performed under cold coolant conditions, until the engine
is warmed up.
[0008] The above information disclosed in this Background section
is only for enhancement of understanding of the background of the
invention and therefore it may contain information that does not
form the prior art that is already known in this country to a
person of ordinary skill in the art.
SUMMARY OF THE INVENTION
[0009] The present invention has been made in an effort to provide
an apparatus for controlling an electric water pump of a hybrid
vehicle. In particular, the apparatuses and methods provide the
advantages of securely controlling the coolant temperature of an
engine by forcibly operating a motorized water pump when the engine
coolant temperature is high and an EV mode or an idle engine stop
mode is performed, so that the engine does not become
overheated.
[0010] The present invention provides a motorized water pump which
may be continuously operated in order to circulate the coolant so
as to securely operate an interior room heating apparatus. In
addition, the present invention provides variable control of the
motorized water pump. The motorized water pump may be varied by
applying a factor value mapped according to a vehicle speed in a
condition where the coolant temperature is high.
[0011] The present invention may also provide optimized cooling
efficiency by variably controlling a motorized water pump according
to a load of a cooling fan in a condition that a motorized water
pump is stopped until the radiator cooling fan is operated after
starting of a cold engine.
[0012] According to one embodiment of the present invention, a
motorized water pump control apparatus of a hybrid vehicle includes
a thermostat which determines a circulation path of the coolant, a
coolant temperature sensor detecting a coolant temperature, a
motorized water pump configured to pump a coolant, and a control
portion controlling the motorized water pump to circulate the
coolant, if the hybrid vehicle enters into an EV mode or an idle
engine stop mode if the coolant temperature exceeds a predetermined
temperature.
[0013] In another embodiment, the control portion may drive the
motorized water pump if operation of a heating apparatus is
demanded in an EV mode or an idle engine stop mode. In yet another
embodiment, the control portion may vary a driving speed of the
motorized water pump according to a vehicle speed if the vehicle
enters into an idle engine stop mode in a condition that the
coolant temperature exceeds a predetermined temperature value.
[0014] In a further embodiment, the control portion may enter into
a limp home mode, output an alarm message, and drive the motorized
water pump to circulate the coolant if an error is detected from
the cooling system.
[0015] A motorized water pump control method of a hybrid vehicle is
also provided. In one embodiment of the present invention, the
method includes the steps of determining whether a hybrid vehicle
enters into an EV mode or an idle engine stop mode, determining
whether the coolant temperature exceeds a predetermined value if
the hybrid vehicle is in the EV mode or the idle engine stop mode,
driving the motorized water pump if the coolant temperature exceeds
the predetermined value and turning off the motorized water pump if
the coolant temperature is less than the predetermined value, and
varying a driving speed of the motorized water pump according to a
vehicle speed if the vehicle speed is larger than a predetermined
value in a condition that the motorized water pump is being
driven.
[0016] In another embodiment, the motorized water pump may be
driven to circulate the coolant if operation of a heating apparatus
is demanded in an EV mode or an idle engine stop mode.
[0017] In a further embodiment, the motorized water pump control
apparatus of a hybrid vehicle may include a thermostat determining
a circulation path of coolant according to the coolant temperature
exhausted from the engine, a radiator emitting heat absorbed in the
coolant, a cooling fan that is disposed at one side of the radiator
to blow air, a motorized water pump that is disposed between the
engine and the thermostat to circulate the coolant, and a control
portion that turns the motorized water pump on/off according to an
operating load of the cooling fan.
[0018] In one embodiment, the control portion may monitor
environmental conditions and driving conditions of the engine, and
enters into a limp home mode so as to operate the motorized water
pump if an error is detected from the monitored data.
[0019] In another embodiment, the control portion may stop
operation of the motorized water pump until the cooling fan is
operated for the first time after ignition start, if the coolant
temperature is lower than a predetermined temperature value.
[0020] In yet another embodiment, the control portion may drive the
motorized water pump at a second speed if the cooling fan is
operated at a low speed, and if the cooling fan is turned off, the
control portion drives the motorized water pump at a first speed
that is slower than the second speed.
[0021] In another embodiment, the control portion may drive the
motorized water pump at a third speed that is faster than the
second speed if the cooling fan is driven at a high speed. In a
further embodiment, if the vehicle speed exceeds a predetermined
value, the control portion increases the driving speed of the
motorized water pump according to a factor value of the vehicle
speed.
[0022] In another embodiment, a motorized water pump control method
of a hybrid vehicle may also include suspending operation of a
motorized water pump in a condition in which the coolant
temperature is less than a predetermined value until a cooling fan
is operated, and controlling a driving speed of the motorized water
pump according to a load of the cooling fan while the cooling fan
is being operated.
[0023] In another embodiment, the motorized water pump may be
driven at a second speed while the cooling fan is being driven at a
low speed.
[0024] In yet another embodiment, the motorized water pump may be
driven at a first speed that is slower than the second speed while
the cooling fan is halted.
[0025] In a further embodiment, the motorized water pump may be
driven at a third speed that is faster than the second speed if it
is determined that the cooling fan is being operated at a high
speed, and it is determined that the engine is in a high load
condition based on a coolant flux that is determined.
[0026] In one embodiment, a factor value according to the vehicle
speed may be applied to drive the motorized water pump faster than
the third speed if the cooling fan is driven at a high speed, the
vehicle speed exceeds a predetermined vehicle speed value, and it
is determined that the engine is in a high speed and high load
condition.
[0027] In another embodiment, the speed of the motorized water pump
may be varied according to the vehicle speed in the high speed or
high load condition of the engine such that the speed of the
motorized water pump is increased or decreased proportionally.
[0028] In yet another embodiment, the coolant may be optimally
circulated according to driving conditions and a vehicle speed such
that the engine is not overheated or overcooled.
[0029] In another embodiment, an interior can be heated by a heater
in the event that the vehicle enters into an EV mode or an idle
engine stop mode.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] So that those having ordinary skill in the art to which the
subject invention pertains will more readily understand how to make
and use the devices and methods of the subject invention, preferred
embodiments thereof will be described in detail herein below with
reference to the drawings, wherein:
[0031] FIG. 1 is a schematic diagram showing a motorized water pump
control apparatus of a hybrid vehicle according to one embodiment
of an apparatus according to the present invention;
[0032] FIG. 2 is a flowchart, corresponding to the schematic
diagram in FIG. 1, showing a motorized water pump control procedure
of a hybrid vehicle according to an embodiment of a method
according to the present invention;
[0033] FIG. 3 is a schematic diagram showing a motorized water pump
control of a hybrid vehicle according to another embodiment of an
apparatus according to the present invention;
[0034] FIG. 4 is a flowchart corresponding to the schematic diagram
in FIG. 3, showing a motorized water pump control procedure of a
hybrid vehicle according to another embodiment of an apparatus of
the present invention; and
[0035] FIG. 5 is a graph, corresponding to the flowchart of FIG. 4,
showing motorized water pump control timing of a hybrid vehicle
according to an embodiment of the present invention.
DESCRIPTION OF SYMBOLS
[0036] 100: engine [0037] 110: thermostat [0038] 120: radiator
[0039] 121: cooling fan [0040] 130: coolant temperature sensor
[0041] 140: motorized water pump [0042] 150: control portion
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0043] In the following detailed description, only certain
exemplary embodiments of the present invention have been shown and
described for purposes of illustration.
[0044] As those skilled in the art would realize, the described
embodiments may be modified in various different ways, all without
departing from the spirit or scope of the present invention, and
the drawings and description are to be regarded as illustrative in
nature and not intended to restrict the scope of the invention to
the particular examples described herein.
[0045] Turning to FIG. 1, a schematic diagram of a motorized water
pump control apparatus of a hybrid vehicle according to one
embodiment of the present invention is shown. The present invention
includes an engine 100, a thermostat 110, a radiator 120, a coolant
temperature sensor 130, a motorized water pump 140, and a control
portion 150.
[0046] In accordance with this exemplary embodiment, the thermostat
110 determines a circulation path of coolant to a bypass line or
the radiator 120 according to the coolant temperature exhausted
from the engine 100.
[0047] The radiator 120 emits heat of the coolant through a contact
area of a core thereof to air, and a cooling fan is disposed at one
side of the core so as to forcibly blow the air through the core
based on the coolant temperature and a driving condition of a
vehicle.
[0048] The coolant temperature sensor 130 detects the temperature
of the coolant flowing into the engine 100 through the radiator 120
or the bypass line, and transmits the detected signal to the
control portion 150.
[0049] The motorized water pump 140 is disposed between the engine
100 and the thermostat, and is turned on or off. The operating
speed is controlled by the control signal which determines whether
or not to circulate the coolant.
[0050] Typically, the motorized water pump 140 is one of a clutch
type or an electric type.
[0051] The control portion 150 determines whether the vehicle
enters into an EV mode or an idle engine stop mode from an HV mode.
If the vehicle enters into the EV mode or the idle engine stop mode
in a condition where the coolant temperature has exceeded a
predetermined value, the control portion 150 drives the motorized
water pump 140 so as to circulate the coolant through the engine
100. In this situation, the motorized water pump 140 drives
circulation of the coolant regardless of the operation of the
engine 100, so that the engine does not overheat.
[0052] In addition, the control portion 150 may drive the motorized
water pump 140 to regularly circulate the coolant so that an
interior room of the vehicle can be heated based on a heating
demand in a case where the vehicle has entered into the EV mode or
the idle engine stop mode.
[0053] In accordance with an embodiment of the present invention,
if the vehicle enters into the idle engine stop mode or the EV mode
when the coolant temperature detected by the temperature sensor 130
has exceeded a predetermined value, typically approximately
90.degree. C. to 96.degree. C., the control portion 150 applies a
factor value mapped according to the vehicle speed to variably
control the motorized water pump 140 and to offer optimized cooling
efficiency. If the coolant temperature detected by the temperature
sensor 130 is less than the predetermined value, the control
portion 150 turns off the motorized water pump 140.
[0054] Also, in a further embodiment, if an error is detected from
the cooling system, the control portion 150 outputs an alarm signal
and simultaneously enters into a limp home mode so as to
continuously operate the motorized water pump 150 so that the
coolant can circulate in the engine.
[0055] Turning to the steps of FIG. 2, the control portion 150
analyzes driving signals detected by sensors step S101, diagnoses
the cooling system step S102, and determines whether the diagnosed
result is normal or not step S103.
[0056] If it is determined that the cooling system is in an
abnormal condition step S103, then the control portion 150 outputs
an alarm signal in a predetermined method, and enters into the limp
home mode so as to continuously operate the motorized water pump
150 so that the coolant is steadily circulated through the engine
step S104.
[0057] If it is determined that the cooling system is in a normal
condition step S103, then the control portion 150 recognizes an on
or off condition of a heater switch step S105 to determine whether
a heating device is on in step S106.
[0058] If it is determined that the heating apparatus is turned on
step S106, the motorized water pump 140 is driven, irrespective of
the coolant temperature step S107 in order to circulate the coolant
such that the interior temperature can be raised step S108.
[0059] If the heating apparatus is not turned on step S106, then a
driving mode is determined step S109, and it is then determined
whether the vehicle enters into the EV mode or the idle engine stop
mode from the HV mode step S110.
[0060] If it is determined that the hybrid vehicle enters into the
EV mode or the idle engine stop mode step S110, then it is
determined whether the coolant temperature exceeds a predetermined
value (about 90.degree. C. to 96.degree. C.) step S111, step
S112.
[0061] However, if the coolant temperature is less than the
predetermined value step S112, then the motorized water pump 140 is
turned off to reduce a load of the engine 100 or a battery,
reducing fuel consumption step S113.
[0062] If the coolant temperature exceeds a predetermined value in
step S112, the motorized water pump 140 is uniformly driven so as
to circulate the coolant step S114.
[0063] While the motorized water pump 140 is being driven to
circulate the coolant, it is determined whether the speed of the
vehicle exceeds a predetermined value step S115.
[0064] If it is determined that the speed of the vehicle exceeds a
predetermined value step S115, then a predetermined factor value
according to the speed of the vehicle is applied to the operation
speed of the motorized water pump 140 and the operation speed is
determined step S116.
[0065] After this, the control portion 150 variably controls the
motorized water pump 140 at a speed determined by the vehicle speed
to circulate the coolant through the engine step S117. In this
case, it is desirable that the higher the vehicle speed, the faster
the operation speed of the motorized water pump.
[0066] Accordingly, the motorized water pump is controlled to be
turned on or off according to the coolant temperature in a case
that the engine is turned off depending on the mode change of the
hybrid vehicle in the present invention so that the engine is
stabilized to improve operating efficiency.
[0067] Also, if the heating apparatus is turned on regardless of an
on or off condition of the engine, the coolant is circulated by the
motorized water pump to heat the interior room, thereby improving
the reliability of the hybrid vehicle.
[0068] FIG. 3 is a schematic diagram showing a motorized water pump
control apparatus of a hybrid vehicle according to another
exemplary embodiment of the present invention.
[0069] This embodiment of the present invention includes an engine
100 as a power source, a thermostat 110, a radiator 120, a
motorized water pump 140, and a control portion 150.
[0070] Here, the thermostat 110 determines a circulation path of
the coolant according to the coolant temperature exhausted from the
engine 100 to a bypass line or the radiator 120 so that coolant is
circulated through the engine 100.
[0071] A coolant temperature sensor 130 detecting the coolant
temperature is disposed inside the thermostat, and the coolant
temperature detected by the coolant temperature sensor 130 is
transmitted to the control portion 150.
[0072] The radiator 120 raises the contact area of the coolant to
the air through a core thereof in order to emit heat energy of the
coolant into the air.
[0073] A cooling fan 121 is disposed at one side of the radiator
120 so as to forcibly blow the air through the radiator 120. The
cooling fan 121 is operated at a low or high speed by the control
portion 150 according to the coolant temperature and the driving
condition, based on whether the coolant temperature is higher than
a predetermined value.
[0074] The motorized water pump 140 is disposed between the engine
100 and the thermostat 110 to be turned on or off depending on the
control signal transmitted from the control portion 150, so that
the operation speed of the control portion 150 is variably
controlled to optimize circulation of the coolant.
[0075] Typically, the motorized water pump 140 is one of a clutch
type or an electric type.
[0076] The control portion 150 is configured to determine a coolant
flux according to a load of the cooling fan 121 forcibly blowing
the air through the radiator 120. The control portion turns the
motorized water pump 140 on or off and variably controls the
operation speed of the motorized water pump 140.
[0077] In this embodiment, the control portion 150 may determine
the outside temperature, engine speed, and coolant temperature
detected by the coolant temperature sensor 130 in order to
determine driving conditions and the environmental state of the
engine 100. If an error is detected from the diagnosed conditions,
the engine 100 outputs an alarm signal and simultaneously enters
into a limp home mode such that the coolant is continuously
circulated by the motorized water pump 140.
[0078] The control portion 150 stops operation of the motorized
water pump 140 until the cooling fan 121 is operated to cool the
radiator 120 in order to shorten a warming up period of the engine
and an activation period of an exhaust catalyst in a case that the
engine is started in a cold state.
[0079] If the cooling fan 121 is operated for the first time after
ignition start, the control portion 150 drives the motorized water
pump 140 at a second driving speed according to the determined
coolant flux. If the cooling fan 121 again stops after the first
operation, the motorized water pump 140 is uniformly operated at a
first driving speed to circulate the coolant until the cooling fan
is operated once more.
[0080] In a case that the cooling fan 121 is driven at a high
speed, the control portion 150 determines the coolant flux
according to the fan speed to drive the motorized water pump 140 in
a third driving speed. If the vehicle speed exceeds a predetermined
value, the control portion 150 applies a factor value according to
the vehicle speed to compensate the driving speed of the motorized
water pump 141 so that the coolant flux can be raised.
[0081] Turning to FIG. 4, according to another embodiment of the
present invention, the control portion 150 detects atmospheric
temperature, engine speed, and coolant temperature through the
coolant temperature sensor 130 step S101, and determines whether
the engine 100 is warmed up or not step S102.
[0082] If it is determined that the engine 100 is in a cold state
step S102, the control portion 150 stops operation of the motorized
water pump 140 so as to warm up the engine step S103. In this case,
a water jacket of the engine 100 functions as a thermos to help the
engine 100 quickly warm up.
[0083] In a condition that the motorized water pump 140 is turned
off, the control portion 150 monitors the operating condition of
the cooling fan 121 for blowing the air through the radiator 120
step S104, and determines whether the cooling fan is operating step
S105.
[0084] If the cooling fan 121 sustains its "off" condition step
S105, the operation is returned step S103 to repeat the above
procedures. If it is determined that the cooling fan 121 is
operating at a predetermined low load, the necessary coolant flux
is determined by the load of the cooling fan 121 step S106 and the
control portion drives the motorized water pump 140 at a second
speed to circulate the coolant such that the engine 100 securely
sustains its condition in a low load condition of the cooling fan
step S107.
[0085] Then, it is determined whether the cooling fan 121 stops
operating or not step S108.
[0086] If it is determined that the cooling fan 121 is operating
step S108, the operation is returned to step S107 such that the
motorized water pump 140 is driven at a second speed to circulate
the coolant. If it is determined that the cooling fan 121 stops
operating step S108, the control portion 150 drives the motorized
water pump 140 at a first speed that is determined by repeated
experiments. In this instance, the first speed is slower than the
second speed, such that a coolant flux is lower than when the
cooling fan is operated step 109.
[0087] In a condition that the motorized water pump 140 is
continuously driven at a first speed, it is determined whether the
cooling fan 121 is operated at a high speed step S110.
[0088] If it is determined that the cooling fan 121 is driven at a
high speed step S110, the necessary coolant flux is determined step
S111, and the control portion drives the motorized water pump 140
at a third speed to circulate a large amount of coolant so that the
temperature of the engine 100 is securely controlled step S112.
[0089] While the motorized water pump 140 is driven at the third
speed as stated above, it is determined whether the vehicle speed
exceeds a predetermined value step S113. In one embodiment, the
predetermined vehicle speed value is approximately, 80 Km/h.
[0090] If the vehicle speed does not exceed a predetermined value
step S113, the operation is returned step S112 to drive the
motorized water pump 140 at a third speed. If the vehicle speed
exceeds the predetermined value, the control portion applies a
factor value according to the high speed of the vehicle step S114,
determines a final flux of the coolant, and compensates the driving
speed of the motorized water pump 140 so as to circulate the
coolant according to a high speed and a high load of the engine
step S115.
[0091] Operations of this invention including the functions as
described above will hereinafter be described in detail with
reference to FIG. 5.
[0092] Turning to FIG. 5, if the engine 100 is started, the
motorized water pump (EWP load) is turned off in order to quickly
warm up the engine such that the coolant is not circulated. If the
cooling fan is driven at a low speed, the control portion drives
the motorized water pump (EWP load) at a second speed P2 to
circulate the coolant.
[0093] After that, since the coolant temperature is decreased by
the operation of the cooling fan, the cooling fan is turned off in
order to uniformly sustain the coolant temperature, and the
motorized water pump (EWP load) is driven at a first speed P1 to
circulate the coolant.
[0094] Further, if the cooling fan is operated at a high speed, it
is determined that the engine is in a high load condition, and the
control portion drives the motorized water pump (EWP load) at a
third speed P3 in order to circulate a greater amount of coolant so
that the engine temperature is securely controlled.
[0095] In one embodiment, in a condition where the motorized water
pump (EWP load) is driven at the third speed P3 according to the
high load operation of the engine, if it is determined that the
vehicle speed exceeds a predetermined vehicle speed value, the
control portion applies a vehicle speed factor to determine a final
coolant flux, and drives the motorized water pump at a speed that
is faster than the third speed such that the engine temperature is
securely controlled by a large amount of circulation of the
coolant.
[0096] In the high speed and high load driving condition, the speed
of the motorized water pump is varied according to the vehicle
speed such that the coolant circulation amount is proportionally
increased or decreased.
[0097] In a situation where the engine is started in a cold state,
the present invention provides decreased warming time and exhaust
catalyst activation time, decreased entry time into the EV mode and
the idle engine stop mode, decreased fuel consumption, and overall
improvement in the exhaust gas quality.
[0098] In addition, because the subject invention provides
circulation of the coolant based on the driving conditions,
overheating of the engine is provided and driving stability and
reliability are improved.
[0099] While this invention has been described in connection with
what is presently considered to be practical exemplary embodiments,
it is to be understood that the invention is not limited to the
disclosed embodiments, but, on the contrary, is intended to cover
various modifications and equivalent arrangements included within
the spirit and scope of the appended claims.
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