U.S. patent application number 13/711530 was filed with the patent office on 2013-10-10 for electronic thermostat.
This patent application is currently assigned to Hyundai Motor Company. The applicant listed for this patent is HYUNDAI MOTOR COMPANY, INZICONTROLS CO., LTD., KIA MOTORS CORPORATION. Invention is credited to Gyuhwan Kim, Yong Jeong Kim, Philgi Lee, Jae Suk Park.
Application Number | 20130263800 13/711530 |
Document ID | / |
Family ID | 49209858 |
Filed Date | 2013-10-10 |
United States Patent
Application |
20130263800 |
Kind Code |
A1 |
Lee; Philgi ; et
al. |
October 10, 2013 |
ELECTRONIC THERMOSTAT
Abstract
An electronic thermostat apparatus for controlling a temperature
of a coolant of an engine in a vehicle may include a housing
connected to a plurality of flow paths through which the coolant of
the engine flows, a wax case installed inside the housing and
provided with a wax accommodation space therein, a glow plug heater
inserted in a wax filled inside the wax accommodation space and
configured to generate heat by receiving an external power, a
driving body engaged to the wax case and moving according to
deformation of the wax by the heat of the glow plug heater, a main
valve engaged to the driving body and configured to open/close a
radiator-side flow path by a movement of the driving body, and an
elastic member elastically biasing the main valve to the
radiator-side flow path.
Inventors: |
Lee; Philgi; (Suwon-si,
KR) ; Kim; Gyuhwan; (Suwon-si, KR) ; Park; Jae
Suk; (Suwon-si, KR) ; Kim; Yong Jeong;
(Ansan-sin, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HYUNDAI MOTOR COMPANY
KIA MOTORS CORPORATION
INZICONTROLS CO., LTD. |
Seoul
Seoul
Siheung-si |
|
KR
KR
KR |
|
|
Assignee: |
Hyundai Motor Company
Seoul
KR
Inzicontrols Co., Ltd.
Siheung-si
KR
Kia Motors Corporation
Seoul
KR
|
Family ID: |
49209858 |
Appl. No.: |
13/711530 |
Filed: |
December 11, 2012 |
Current U.S.
Class: |
123/41.08 |
Current CPC
Class: |
F01P 7/16 20130101; F01P
2070/04 20130101; G05D 23/1921 20130101 |
Class at
Publication: |
123/41.08 |
International
Class: |
F01P 7/16 20060101
F01P007/16 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 9, 2012 |
KR |
10-2012-0036932 |
Claims
1. An electronic thermostat apparatus for controlling a temperature
of a coolant of an engine in a vehicle, the electronic thermostat
apparatus comprising: a housing connected to a plurality of flow
paths through which the coolant of the engine flows; a wax case
installed inside the housing and provided with a wax accommodation
space therein; a glow plug heater inserted in a wax filled inside
the wax accommodation space and configured to generate heat by
receiving an external power; a driving body engaged to the wax case
and moving according to deformation of the wax by the heat of the
glow plug heater; a main valve engaged to the driving body and
configured to open/close a radiator-side flow path by a movement of
the driving body; and an elastic member elastically biasing the
main valve to the radiator-side flow path.
2. The electronic thermostat apparatus of claim 1, further
including: a bypass valve coupled to the driving body and
configured to open/close a bypass flow path that does not circulate
through a radiator while interworking with the main valve.
3. The electronic thermostat apparatus of claim 1, wherein the
electronic thermostat apparatus is installed at an inlet of the
engine through which the coolant flows in the engine or an outlet
of the engine through which the coolant is discharged from the
engine.
4. The electronic thermostat apparatus of claim 1, wherein the glow
plug heater includes a cylindrical case, a heating tube coupled to
one end of the case, a coil installed inside the heating tube, and
an insulation member filled in a space between the coil and the
heating tube.
5. The electronic thermostat apparatus of claim 4, wherein the coil
includes a heating coil configured to generate the heat or a
temperature adjusting coil configured to control an increase in a
temperature of the heating coil.
6. The electronic thermostat apparatus of claim 4, wherein the
insulation member is made of magnesium oxide (MgO) powder.
7. The electronic thermostat apparatus of claim 1, wherein a
transmission fluid is disposed between the wax and the driving body
in a cylindrical element guide connected to the wax case.
8. The electronic thermostat apparatus of claim 7, wherein a rubber
moving body is disposed between the transmission fluid and the
driving body.
9. The electronic thermostat apparatus of claim 7, wherein an inner
diameter of a cylindrical frame receiving the wax case is larger
than an inner diameter of a cylindrical element guide slidably
receiving the driving body.
10. An electronic thermostat apparatus for cooling a temperature of
a coolant of an engine in a vehicle, the electronic thermostat
apparatus employing a glow plug heater that heats a wax.
11. The electronic thermostat apparatus of claim 10, wherein the
glow plug heater includes: a cylindrical case; a heating tube
coupled to one end of the case; a coil installed inside the heating
tube; and an insulation member filled in a space between the coil
and the heating tube.
12. The electronic thermostat apparatus of claim 11, wherein the
coil includes a heating coil configured to generate heat or a
temperature adjusting coil configured to control an increase in a
temperature of the heating coil.
13. The electronic thermostat apparatus of claim 11, wherein the
insulation member is made of magnesium oxide (MgO) powder.
14. The electronic thermostat apparatus of claim 11, wherein a
transmission fluid is disposed between the wax disposed in the
cylindrical case and a driving body disposed in a cylindrical
element guide connected to a wax case containing the wax.
15. The electronic thermostat apparatus of claim 14, wherein a
rubber moving body is disposed between the transmission fluid and
the driving body.
16. The electronic thermostat apparatus of claim 14, wherein an
inner diameter of a frame receiving the wax case is larger than an
inner diameter of the cylindrical element guide
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application claims priority to Korean Patent
Application No. 10-2012-0036932 filed on Apr. 9, 2012, the entire
contents of which is incorporated herein for all purposes by this
reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to an electronic thermostat,
and more particularly, to an electronic thermostat capable of
rapidly reaching a target temperature by employing a glow plug type
heater.
[0004] 2. Description of Related Art
[0005] In general, a thermostat for a vehicle is installed between
an engine and a radiator, and is automatically opened/closed
according to a change in a temperature of a coolant to adjust a
flow rate flowing toward the engine, thus serving to maintain an
appropriate temperature of the coolant.
[0006] Most of the thermostats for a vehicle in the related art are
a mechanical thermostat having a structure in which power by
expansion of wax is transferred to a piston to incur an open/close
displacement of a valve.
[0007] However, the mechanical thermostat employs a method of
operating according to an open/close temperature set as a specified
temperature, that is, a method of simply opening/closing a valve
only at a preset temperature. Accordingly, in consideration recent
demands of implementing high performance and high efficiency of a
vehicle, there is a limit in actively handling a change in a
driving environment or other conditions of the vehicle.
[0008] An electronic thermostat employing a variable control method
for maintaining a temperature of a coolant of an engine in an
optimum state while complementing a drawback of the mechanical
thermostat has been recently suggested.
[0009] The electronic thermostat controls the temperature of the
coolant of the engine according to a driving environment, such as a
load state of the vehicle and the like, so that it is possible to
always maintain an optimum engine cooling state and expect effects
of improving fuel efficiency and decreasing an exhaust gas compared
to the mechanical thermostat.
[0010] FIG. 1 illustrates an example of the electronic thermostat.
As illustrated in FIG. 1, the electronic thermostat generally has a
structure in which wax 2 is accommodated in a pallet 1, a heat
generation unit 3, such as a film resistant heater, is embedded at
a front end thereof, and the heater generates heat through an
external power supply plug to expand the wax and push a piston, so
that a valve is operated.
[0011] In the electronic thermostat generating heat by using the
film resistant heater and the like in the related art, it takes
approximately 50 to 70 seconds to reach a target temperature of 300
to 350.degree. C. It takes a great deal of time to reach the target
temperature, so that there is a problem in that it is impossible to
control a temperature of the coolant in real time and it is
difficult to maximize an effect of improving fuel efficiency of a
vehicle.
[0012] The information disclosed in this Background of the
Invention section is only for enhancement of understanding of the
general background of the invention and should not be taken as an
acknowledgement or any form of suggestion that this information
forms the prior art already known to a person skilled in the
art.
BRIEF SUMMARY
[0013] Various aspects of the present invention are directed to
providing an electronic thermostat capable of controlling a
temperature of a coolant in real time and maximizing an effect of
improving fuel efficiency of a vehicle by improving a control
response characteristic of the electronic thermostat.
[0014] In an aspect of the present invention, an electronic
thermostat apparatus for controlling a temperature of a coolant of
an engine in a vehicle, may include a housing connected to a
plurality of flow paths through which the coolant of the engine
flows, a wax case installed inside the housing and provided with a
wax accommodation space therein, a glow plug heater inserted in a
wax filled inside the wax accommodation space and configured to
generate heat by receiving an external power, a driving body
engaged to the wax case and moving according to deformation of the
wax by the heat of the glow plug heater, a main valve engaged to
the driving body and configured to open/close a radiator-side flow
path by a movement of the driving body, and an elastic member
elastically biasing the main valve to the radiator-side flow
path.
[0015] The electronic thermostat apparatus may further include a
bypass valve coupled to the driving body and configured to
open/close a bypass flow path that does not circulate through a
radiator while interworking with the main valve.
[0016] The electronic thermostat apparatus is installed at an inlet
of the engine through which the coolant flows in the engine or an
outlet of the engine through which the coolant is discharged from
the engine.
[0017] The glow plug heater may include a cylindrical case, a
heating tube coupled to one end of the case, a coil installed
inside the heating tube, and an insulation member filled in a space
between the coil and the heating tube.
[0018] The coil may include a heating coil configured to generate
the heat or a temperature adjusting coil configured to control an
increase in a temperature of the heating coil.
[0019] The insulation member is made of magnesium oxide (MgO)
powder.
[0020] A transmission fluid is disposed between the wax and the
driving body in a cylindrical element guide connected to the wax
case.
[0021] A rubber moving body is disposed between the transmission
fluid and the driving body.
[0022] An inner diameter of a cylindrical frame receiving the wax
case is larger than an inner diameter of a cylindrical element
guide slidably receiving the driving body.
[0023] In another aspect of the present invention, an electronic
thermostat apparatus for cooling a temperature of a coolant of an
engine in a vehicle may employ a glow plug heater that heats a
wax.
[0024] The glow plug heater may include a cylindrical case, a
heating tube coupled to one end of the case, a coil installed
inside the heating tube, and an insulation member filled in a space
between the coil and the heating tube.
[0025] The coil may include a heating coil configured to generate
heat or a temperature adjusting coil configured to control an
increase in a temperature of the heating coil.
[0026] The insulation member is made of magnesium oxide (MgO)
powder.
[0027] A transmission fluid is disposed between the wax disposed in
the cylindrical case and a driving body disposed in a cylindrical
element guide connected to a wax case containing the wax.
[0028] A rubber moving body is disposed between the transmission
fluid and the driving body.
[0029] An inner diameter of a frame receiving the wax case is
larger than an inner diameter of the cylindrical element guide
[0030] According to the electronic thermostat according to the
exemplary embodiment of the present invention, it is possible to
minimize a time required to reach a target temperature by using the
glow plug type heater. Accordingly, it is possible to control a
temperature of a coolant in real time according to a driving
condition of a vehicle.
[0031] Further, according to the present invention, a temperature
of a coolant is controlled in real time, thereby maximally
improving fuel efficiency of a vehicle.
[0032] The methods and apparatuses of the present invention have
other features and advantages which will be apparent from or are
set forth in more detail in the accompanying drawings, which are
incorporated herein, and the following Detailed Description, which
together serve to explain certain principles of the present
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] FIG. 1 is a cross-sectional view of an electronic thermostat
in the related art.
[0034] FIG. 2 is a cross-sectional view of an electronic thermostat
according to an exemplary embodiment of the present invention.
[0035] FIG. 3 is a cross-sectional view of a glow plug type heater
according to an exemplary embodiment of the present invention.
[0036] FIG. 4 is a diagram schematically illustrating a coolant
flow path at which an electronic thermostat of the present
invention is installed.
[0037] FIG. 5 is a cross-sectional view of a coolant flow path at
which an electronic thermostat of the present invention is
installed
[0038] FIG. 6 is a perspective view of a coolant flow path at which
an electronic thermostat of the present invention is installed.
[0039] It should be understood that the appended drawings are not
necessarily to scale, presenting a somewhat simplified
representation of various features illustrative of the basic
principles of the invention. The specific design features of the
present invention as disclosed herein, including, for example,
specific dimensions, orientations, locations, and shapes will be
determined in part by the particular intended application and use
environment.
[0040] In the figures, reference numbers refer to the same or
equivalent parts of the present invention throughout the several
figures of the drawing.
DETAILED DESCRIPTION
[0041] Reference will now be made in detail to various embodiments
of the present invention(s), examples of which are illustrated in
the accompanying drawings and described below. While the
invention(s) will be described in conjunction with exemplary
embodiments, it will be understood that the present description is
not intended to limit the invention(s) to those exemplary
embodiments. On the contrary, the invention(s) is/are intended to
cover not only the exemplary embodiments, but also various
alternatives, modifications, equivalents and other embodiments,
which may be included within the spirit and scope of the invention
as defined by the appended claims.
[0042] Hereinafter, exemplary embodiments of the present invention
will be described in detail with reference to the accompanying
drawings.
[0043] FIG. 2 is a cross-sectional view of an electronic thermostat
10 according to an exemplary embodiment of the present
invention.
[0044] As illustrated in FIG. 2, the electronic thermostat 10
according to the exemplary embodiment of the present invention may
include a housing 100, a wax case 200, a glow plug type heater 300,
a driving body 400, a main valve 500, an elastic member 600, and a
bypass valve 700.
[0045] The housing 100 is a part connected to a plurality of flow
paths through which a coolant of an engine of a vehicle flows. As
illustrated in FIGS. 4 to 6 as the exemplary embodiment, the
housing 100 may be connected with a radiator-side flow path P1
through which the coolant flows in after circulating the radiator
20, a bypass flow path P2 through which the coolant directly
circulates toward the water pump 30 of the engine 40 without
circulating the radiator 20, and a water pump-side flow path P3 at
an inlet through which the coolant flows in the engine 40.
[0046] A fixed part 110 is integrally formed inside the housing
100, so that the glow plug type heater 300 may be fixed.
[0047] A space for accommodating a connector 350 connecting the
thermostat 10 to external power may be formed in the fixed part
110.
[0048] The wax case 200 is installed inside the housing 100, and
has a wax accommodation space for filling the inside of the wax
case 200 with the wax 210.
[0049] The wax case 200 may be installed under the fixed part 110
of the housing 100, and may have a through hole 220 formed inside
thereof so that a heating tube 320 of the glow plug type heater 300
passes through the through hole 220 to be inserted in the wax
accommodation space.
[0050] The glow plug type heater 300 is inserted in the wax 210
filled in the wax accommodation space of the wax case 200, and
generates heat by receiving external power through the connector
350. The glow plug type heater 300 is electronically controlled
under the control of an external controller, such as an electronic
control unit (ECU).
[0051] In general, a glow plug is an apparatus used for a diesel
engine and the like to pre-heat interior air so as to help ignition
of fuel.
[0052] That is, the present invention is characterized in that the
glow plug used for ignition of the diesel engine and the like is
applied as the heater 300 of the thermostat 100, contrary to the
related art.
[0053] FIG. 3 is a cross-sectional view of the glow plug type
heater 300 according to an exemplary embodiment of the present
invention.
[0054] As illustrated in FIG. 3, the glow plug type heater 300
according to the exemplary embodiment of the present invention may
include a cylindrical case 310, a heating tube 320 coupled to one
end of the case 310, a coil 330 installed inside the heating tube
320, and an insulation member 340 filled inside a space between the
coil 330 and the heating tube 320.
[0055] The case 310 may be formed of a metal material, and may be
coupled with the connector 350 connecting the external power at an
upper portion thereof and coupled with the wax case 200 of the
thermostat 10 at a lower portion thereof.
[0056] The heating tube 320 may be formed so that one end thereof
is closed, and may be inserted inside the wax 210 filled inside the
wax accommodation space. The heating tube 320 serves to increase a
temperature of the wax 210 by using the heat generated from the
coil 330 and prevent the coil 330 from being chemically
corroded.
[0057] In one or multiple exemplary embodiments, as illustrated in
FIG. 2, the heating tube 320 may be forcibly inserted and installed
between an interior circumferential surface of the cylindrical case
310 and a core shaft 351 inserted from the connector 350 up to an
inside of the case 310 to conduct electricity, and one end of the
heating tube 320 may be formed in a curved surface by swanging.
[0058] Specifically, as illustrated in FIG. 3A, the coil 330 may
include a heating coil 331 for generating heat by power applied
from the outside and a temperature adjusting coil 332 for
maintaining a uniform temperature by controlling temperature
increase according to a change in inherent resistance according to
an increase in a temperature of the heating coil 331.
[0059] One end of the heating coil 331 may be fixed to an interior
circumferential surface of the heating tube 320 by welding, and the
temperature adjusting coil 332 may be electrically connected to the
core shaft 351.
[0060] In one or multiple exemplary embodiments, the heating coil
331 may be coupled to an interior circumferential surface B of the
heating tube 320 by laser welding, and similarly, the temperature
adjusting coil 332 may be fixed to one end A of the core shaft 351
by laser welding and electrically connected with the core shaft
351.
[0061] In the meantime, in another exemplary embodiment, the coil
330 may only include the heating coil 331 for generating heat by
power applied from the outside as illustrated in FIG. 3B. In this
case, in one or multiple exemplary embodiment, one end of the
heating coil 331 may be coupled to the interior circumferential
surface B of the heating tube 320 by laser welding and the other
end of the heating coil may be coupled to the end A of the core
shaft 351 by laser welding.
[0062] The insulation member 340 is filled inside the heating tube
320.
[0063] In one or multiple exemplary embodiments, the insulation
member 340 may be magnesium oxide (MgO) powder. The magnesium oxide
(MgO) powder, which is an insulator, serves to maintain insulation
between the heating tube 320 and the coil 330, prevent movement of
the coil 330, and transfer heat generated in the coil 330 to the
heating tube 320.
[0064] In the meantime, the driving body 400 is disposed under the
wax case 200 to be moved by deformation of the wax 210.
[0065] In one or multiple exemplary embodiments, as illustrated in
FIG. 2, the driving body 400 is disposed inside a cylindrical
element guide 410 coupled to one end of the wax case 200 to move.
Further, a rubber moving body 440 may be disposed inside the
element guide 410 and on the driving body 400, a transmission fluid
430 may be filled in an upper portion of the rubber moving body
440, and a diaphragm 420 may be formed between an upper surface of
the transmission fluid 430 and the wax 210. Here, the transmission
fluid 430 may be semifluid.
[0066] A space filled with the transmission fluid 430 inside the
element guide 410 may include a slanted surface a diameter of which
becomes gradually smaller as becoming closer from an upper portion
at which the diaphragm 420 is installed to a lower portion.
Accordingly, pressure of the transmission fluid 430 according to
deformation of the diaphragm 420 may be concentrated to the rubber
moving body 440, and the rubber moving body 440 pressurizes the
driving body 400 disposed under the rubber moving body 440 with
force of the concentrated pressure. Accordingly, through the
aforementioned structure, the expansion pressure of the wax 210 may
be transferred to the driving body 400 without loss, so that it is
possible to accurately control flow of the coolant.
[0067] The main valve 500 performs a function of opening/closing
the radiator-side flow path P1 by the movement of the driving body
400. The radiator-side flow path P1 is a flow path allowing the
coolant discharged from the engine 40 to circulate through the
radiator 20 and flow in the engine 40.
[0068] The elastic member 600 is disposed in a lower surface of the
main valve 500 to perform a function of elastically supporting the
main valve 500 to the radiator-side flow path P 1. Accordingly,
when force is not applied from the outside, the main valve 500
closes the radiator-side flow path P1 by elastic force of the
elastic member 600.
[0069] In the meantime, the bypass valve 700 opens/closes the
bypass flow path P2 where the coolant does not circulate through
the radiator 20 by interworking with the main valve 500. The bypass
flow path P2 is a flow path allowing the coolant discharged from
the engine 40 to directly flow in the water pump 30 of the engine
without passing through the radiator 20. The bypass valve 700 may
be disposed under the driving body 400 to be moved by pressure of
the driving body 400.
[0070] In one or multiple exemplary embodiments, the main valve 500
and the bypass valve 700 may be connected through a frame 710 to be
integrally formed as illustrated in FIG. 2. In this case, the
bypass valve 700 and the main valve 50 move together by the
pressure of the driving body 400.
[0071] In the meantime, the electronic thermostat 10 of the present
invention including the aforementioned configuration may be
installed at an inlet of the engine 40 through which the coolant
flows in the engine 40 or an outlet of the engine 40 through which
the coolant is discharged from the engine 40.
[0072] FIG. 4 is a diagram illustrating an exemplary embodiment in
which the electronic thermostat 10 according to the exemplary
embodiment of the present invention is installed at the inlet of
the engine 40, FIG. 5 is a cross-sectional view in which the
electronic thermostat 10 according to the exemplary embodiment of
the present invention is connected to and installed at the coolant
flow path, and FIG. 6 is a perspective view of a coolant flow path
at which the electronic thermostat 10 according to the exemplary
embodiment of the present invention is installed.
[0073] Hereinafter, an operation of the electronic thermostat 10
according to the exemplary embodiment of the present invention will
be described with reference to FIGS. 2 to 6.
[0074] In a case where the coolant of the engine 40 is maintained
at a set temperature, the main valve 500 closes the radiator-side
flow path P1 by the elastic member 600 as illustrated in FIG.
2.
[0075] In this case, as illustrated in FIGS. 4 to 6, the coolant
discharged from the engine 40 does not circulate through the
radiator 20 and directly flows in the engine 40 through the water
pump-side flow path P3 while passing through the bypass flow path
P2.
[0076] In this situation, when a temperature of the coolant is
increased by an operation of the engine 40 and thus becomes higher
than the set temperature, the ECU instructs an operation of the
glow plug type heater 300 in order to open the main valve 500.
Accordingly, the external power is applied to the coil 300 through
the connector 350, so that the temperature of the coil rapidly
reaches the target temperature.
[0077] As the coil 330 of the glow plug type heater 300 generates
heat, the wax 210 is expanded, and the diaphragm 420 that is in
contact with the wax 210 receives pressure to be deformed. The
pressure according to the deformation of the diaphragm 420 is
transferred up to the driving body 400 by sequentially passing
through the transmission fluid 430 and the rubber moving body 440.
The driving body 400 moves down to apply pressure to the bypass
valve 700, and thus the bypass valve 700 moves down.
[0078] The bypass valve 700 moves down to block the bypass flow
path P2. Further, the main valve 500 integrally connected with the
bypass valve 700 through the frame 710 simultaneously moves down to
open the radiator-side flow path P1. Accordingly, as illustrated in
FIG. 4, the coolant discharged from the engine 40 circulates
through the radiator 20 through a flow path P1' and then moves to
the water pump-side flow path P3 through the radiator-side flow
path P1 to flow in the engine 40. In this process, the coolant is
heat-exchanged in the radiator 20, so that a temperature of the
coolant is decreased.
[0079] When the temperature of the coolant becomes lower than the
set temperature, the ECU recognizes the decrease of the temperature
of the coolant and instructs to stop an operation of the glow plug
type heater 300. Accordingly, the heat generation of the coil 330
is stopped and the expanded wax 210 is contracted, so that the
driving body 400 moves up. Accordingly, the pressure of the driving
body 400 pressing the bypass valve 700 disappears, so that the main
valve 500 moves up by the elastic force of the elastic member 600
to close the radiator-side flow path P1, and the bypass valve 700
simultaneously moves up to open the bypass flow path P2.
[0080] Through the aforementioned process, the ECU electronically
controls the thermostat 10, so that the temperature of the coolant
may be uniformly maintained at a preset temperature.
[0081] Especially, according to an exemplary embodiment of the
present invention, a temperature of the heater may rapidly reach a
target temperature by employing the glow plug type heater 300,
thereby rapidly and accurately controlling the temperature of the
coolant. According to the comparison of the experimental results,
in the related art employing the film resistant heater, it takes 50
to 70 seconds to reach a target temperature of 300 to 350.degree.
C., but in an exemplary embodiment of the present invention
employing the glow plug type heater 300, it takes 30 seconds or
shorter to reach a target temperature of 350.degree. C., so that
the present invention has a remarkably improved effect compared to
the related art.
[0082] According to an exemplary embodiment of the present
invention, the glow plug type heater 300 is applied to the
electronic thermostat 10, so that it is possible to minimize a time
required to increase a temperature of the coolant to a target
temperature, and a heating amount of the glow plug type heater is
electronically controlled through the pulse width modulation (PWM)
control by the ECU, so that a characteristic of a cooling system
may be diversified.
[0083] For convenience in explanation and accurate definition in
the appended claims, the terms "upper", "lower", "inner" and
"outer" are used to describe features of the exemplary embodiments
with reference to the positions of such features as displayed in
the figures.
[0084] The foregoing descriptions of specific exemplary embodiments
of the present invention have been presented for purposes of
illustration and description. They are not intended to be
exhaustive or to limit the invention to the precise forms
disclosed, and obviously many modifications and variations are
possible in light of the above teachings. The exemplary embodiments
were chosen and described in order to explain certain principles of
the invention and their practical application, to thereby enable
others skilled in the art to make and utilize various exemplary
embodiments of the present invention, as well as various
alternatives and modifications thereof It is intended that the
scope of the invention be defined by the Claims appended hereto and
their equivalents.
* * * * *