U.S. patent application number 16/991479 was filed with the patent office on 2020-11-26 for refrigerator.
The applicant listed for this patent is LG ELECTRONICS INC.. Invention is credited to Sangbok CHOI, Sung JHEE, Sungwook KIM, Kyongbae PARK.
Application Number | 20200370815 16/991479 |
Document ID | / |
Family ID | 1000005016180 |
Filed Date | 2020-11-26 |
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United States Patent
Application |
20200370815 |
Kind Code |
A1 |
KIM; Sungwook ; et
al. |
November 26, 2020 |
REFRIGERATOR
Abstract
A refrigerator includes an inner case defining a storage
chamber; a cold-air duct for guiding air flowing in the storage
chamber and forming a heat exchange space, together with the inner
case; an evaporator positioned in the heat exchange space; a bypass
passage disposed at the cold-air duct and allowing air to flow
while bypassing the evaporator; a sensor disposed in the bypass
passage and having an output value which changes according to the
flow rate of the air flowing through the bypass passage; a
defroster for removing frost generated on a surface of the
evaporator; and a controller for controlling the defroster on the
basis of the value output by the sensor.
Inventors: |
KIM; Sungwook; (Seoul,
KR) ; PARK; Kyongbae; (Seoul, KR) ; CHOI;
Sangbok; (Seoul, KR) ; JHEE; Sung; (Seoul,
KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
LG ELECTRONICS INC. |
Seoul |
|
KR |
|
|
Family ID: |
1000005016180 |
Appl. No.: |
16/991479 |
Filed: |
August 12, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/KR2018/012711 |
Oct 25, 2018 |
|
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16991479 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F25D 21/02 20130101;
F25D 21/006 20130101 |
International
Class: |
F25D 21/00 20060101
F25D021/00; F25D 21/02 20060101 F25D021/02 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 23, 2018 |
KR |
10-2018-0021938 |
Claims
1. A refrigerator comprising: an inner case defining a storage
space; a cool air duct to guide a flow of air within the storage
space, the cool air duct defining a heat-exchange space together
with the inner case; an evaporator disposed in the heat-exchange
space; a bypass passage disposed at the cool air duct, the bypass
passage providing for a portion of the air flow to bypass the
evaporator; a sensor disposed in the bypass passage, the sensor
having an output value varying according to a flow rate of the
portion of the air flowing through the bypass passage; a defroster
to remove frost generated on a surface of the evaporator; and a
controller configured to control the defroster based on the output
value of the sensor.
2. The refrigerator of claim 1, wherein the sensor comprises: a
heat generating element; a sensing element to sense a temperature
of the heat generating element; and a sensor printed circuit board
(PCB) on which the heat generating element and the sensing element
are installed.
3. The refrigerator of claim 2, wherein, when a difference value
between a temperature sensed by the sensing element in a state in
which the heat generating element is turned on and a temperature
sensed by the sensing element in a state in which the heat
generating element is turned off is equal to or less than a
reference temperature value, the controller is configured to
operate the defroster.
4. The refrigerator of claim 2, wherein the sensor further
comprises a sensor housing surrounding the heat generating element,
the sensing element, and the sensor PCB.
5. The refrigerator of claim 1, further comprising a passage cover
to cover the bypass passage so as to partition the bypass passage
from the heat exchange space.
6. The refrigerator of claim 5, wherein the cool air duct comprises
an elongated extension surface that is a surface in which the
bypass passage is defined, and the passage cover comprises: a cover
plate to cover the bypass passage; and a barrier extending from the
cover plate, the barrier protruding downward from the elongated
extension surface in a state in which the cover plate covers the
bypass passage.
7. The refrigerator of claim 6, wherein the bypass passage extends
along the elongated extension surface in a straight-line shape.
8. The refrigerator of claim 6, wherein the barrier further
comprises: a rear barrier continuously extending from the cover
plate, the rear barrier being disposed adjacent to the evaporator;
a plurality of side barriers extending from the rear barrier, the
plurality of side barriers being spaced apart from each other in a
left and right direction; and a front barrier connected to the
plurality of side barriers, spaced apart from the rear barrier, and
disposed at an opposite side of the evaporator with respect to the
rear barrier.
9. The refrigerator of claim 8, wherein the barrier has an opened
bottom surface, and the front barrier, the plurality of side
barriers, and the rear barrier define a guide passage to guide the
portion of the air to the bypass passage.
10. The refrigerator of claim 8, wherein the cool air duct further
comprises an inclined surface extending to be inclined from an end
of the elongated extension surface and to guide the air towards the
evaporator, and a slot provided at the rear barrier to define a
passage for allowing the air flowing along the inclined surface to
flow towards the evaporator.
11. The refrigerator of claim 5, wherein the cool air duct
comprises a bottom wall and two sidewalls, which define the bypass
passage, the passage cover comprises a cover plate to cover the
bypass passage in a state of being spaced apart from the bottom
wall, and the sensor is disposed to be spaced apart from the bottom
wall and the cover plate in the bypass passage.
12. The refrigerator of claim 11, wherein the sensor is disposed to
be spaced apart from an inlet and an outlet of the bypass passage,
and the sensor is disposed at a point at which a distance between
the bottom wall and the cover plate is bisected in the bypass
passage.
13. The refrigerator of claim 12, wherein the sensor is disposed
closer to the outlet than the inlet of the bypass passage.
14. The refrigerator of claim 5, wherein at least a portion of the
bypass passage and the passage cover is disposed to face the
evaporator within a range of a left and right width of the
evaporator.
15. The refrigerator of claim 5, wherein a blower fan is disposed
at the cool air duct, a cool air inflow hole into which the air is
introduced is defined in the cool air duct, and the bypass passage
does not overlap with the cool air inflow hole in a vertical
direction.
16. The refrigerator of claim 15, wherein an outlet of the bypass
passage is disposed in a region outside of a limit region having a
diameter greater than a diameter of the blower fan with respect to
a center of the blower fan.
17. The refrigerator of claim 16, wherein the outlet of the bypass
passage is disposed higher than an upper end of the evaporator.
18. The refrigerator of claim 16, wherein the limit region has a
diameter set to 1.5 times or more than the diameter of the blower
fan.
19. The refrigerator of claim 1, further comprising a blocking rib
to block an introduction of liquid into the bypass passage and
disposed above the bypass passage in the cool air duct.
20. The refrigerator of claim 19, wherein the blocking rib has a
left-right minimum length greater than a left-right minimum width
of the bypass passage, and the entire bypass passage in the left
and right direction is disposed to overlap the blocking rib in the
vertical direction.
Description
[0001] This application is a continuation of International
Application No. PCT/KR2018/012711 filed on Oct. 25, 2018, which
claims priority to Korean Patent Application No. 10-2018-0021938,
filed on Feb. 23, 2018, all of which are incorporated by reference
in their entirety herein.
TECHNICAL FIELD
[0002] This specification relates to a refrigerator.
BACKGROUND ART
[0003] Refrigerators are household appliances that are capable of
storing objects such as food at a low temperature in a storage
space provided in a cabinet. Since the storage space is surrounded
by heat insulation wall, the inside of the storage space may be
maintained at a temperature less than an external temperature.
[0004] The storage space may be classified into a refrigerating
storage space or a freezing storage space according to a
temperature range of the storage space.
[0005] The refrigerator may further include an evaporator for
supplying cool air to the storage space. Air in the storage space
is cooled while flowing to a space, in which the evaporator is
disposed, so as to be heat-exchanged with the evaporator, and the
cooled air is supplied again to the storage space.
[0006] Here, if the air heat-exchanged with the evaporator contains
moisture, when the air is heat-exchanged with the evaporator, the
moisture freezes on a surface of the evaporator to generate frost
on the surface of the evaporator.
[0007] Since flow resistance of the air acts on the frost, the more
an amount of frost frozen on the surface of the evaporator
increases, the more the flow resistance increases. As a result,
heat-exchange efficiency of the evaporator may be deteriorated, and
thus, power consumption may increase.
[0008] Thus, the refrigerator further includes a defroster for
removing the frost on the evaporator.
[0009] A defrosting cycle variable method is disclosed in Korean
Patent Publication No. 2000-0004806 that is a prior art
document.
[0010] In the prior art document, the defrosting cycle is adjusted
using a cumulative operation time of the compressor and an external
temperature.
[0011] However, when the defrosting cycle is determined only using
the cumulative operation time of the compressor and the external
temperature, an amount of frost (hereinafter, referred to as a
frost generation amount) on the evaporator is not accurately
reflected. Thus, it is difficult to accurately determine the time
point at which the defrosting is required.
[0012] That is, the frost generation amount may increase or
decrease according to various environments such as the user's
refrigerator usage pattern and the degree to which air retains
moisture. In the case of the prior art document, there is a
disadvantage in that the defrosting cycle is determined without
reflecting the various environments.
[0013] Accordingly, there is a disadvantage in that the defrosting
does not start despite a large amount of generated frost that
deteriorates cooling performance, or the defrosting starts despite
a small amount of generated frost that increases power consumption
due to unnecessary defrosting.
SUMMARY
Technical Problem
[0014] The present disclosure provides a refrigerator that is
capable of determining whether a defrosting operation should be
performed by using a parameter that varies depending on an amount
of frost generated on an evaporator.
[0015] In addition, the present disclosure provides a refrigerator
that is capable of accurately determining a time point at which
defrosting is required according to an amount of frost generated on
an evaporator by using a bypass passage for sensing the generated
frost.
[0016] In addition, the present disclosure provides a refrigerator
that is capable of minimizing a length of a passage for sensing
generated frost.
[0017] In addition, the present disclosure provides a refrigerator
that is capable of accurately determining a time point at which
defrosting is required even though accuracy of a sensor is used for
determining the time point at which the defrosting is required.
[0018] In addition, the present disclosure provides a refrigerator
that is capable of preventing frost from being generated around a
sensor for sensing generated frost.
[0019] In addition, the present disclosure provides a refrigerator
that is capable of preventing liquid from being introduced into a
bypass passage for sensing generated frost.
Technical Solution
[0020] A refrigerator for achieving the above objects includes a
cool air duct inside an inner case configured to define a storage
space, and the cool air duct defines a heat-exchange space together
with the inner case.
[0021] An evaporator is disposed in the heat exchange space, a
bypass passage is disposed at the cool air duct, and a sensor is
disposed in a bypass passage.
[0022] In the present disclosure, the sensor may be a sensor having
an output value varying according to a flow rate of the air flowing
through the bypass passage, and a time point at which defrosting
for the evaporator is required may be determined by using the
output value of the sensor.
[0023] The refrigerator according to this embodiment includes a
defroster configured to remove frost generated on a surface of the
evaporator and a controller configured to control the defroster
based on the output value of the sensor. When it is determined that
the defrosting is required, the controller may operate the
defroster.
[0024] In this embodiment, the sensor may include: a heat
generating element; a sensing element configured to sense a
temperature of the heat generating element; and a sensor PCB on
which the heat generating element and the sensing element are
installed.
[0025] The sensor may further include a sensor housing configured
to surround the heat generating element, the sensing element, and
the sensor PCB.
[0026] In this embodiment, when a difference value between a
temperature sensed by the sensing element in a state in which the
heat generating element is turned on and a temperature sensed by
the sensing element in a state in which the heat generating element
is turned off is equal to or less than a reference temperature
value, it may be determined that the defrosting is required.
[0027] In this embodiment, the refrigerator may further include a
passage cover configured to cover the bypass passage so as to
partition the bypass passage from the heat exchange space.
[0028] In this embodiment, the cool air duct may further include a
vertical extension surface that is a surface in which the bypass
passage is defined, and the passage cover may include: a cover
plate configured to cover the bypass passage; and a barrier
extending from the cover plate, the barrier protruding downward
from the vertical extension surface in a state in which the cover
plate covers the bypass passage, and thus, a flow rate of the air
flowing through the bypass passage before the frost is generated
may be reduced.
[0029] In this embodiment, the bypass passage may extend vertically
from the vertical extension surface in a straight-line shape so
that the bypass passage is minimized in length.
[0030] The barrier protruding to the outside of the bypass passage
may further include: a rear barrier continuously extending from the
cover plate, the rear barrier being disposed adjacent to the
evaporator; a plurality of side barriers extending from the rear
barrier, the plurality of side barriers being spaced apart from
each other in a left and right direction; and a front barrier
connected to the plurality of side barriers, spaced apart from the
rear barrier, and disposed at an opposite side of the evaporator
with respect to the rear barrier.
[0031] In this embodiment, the cool air duct may further include an
inclined surface extending to be inclined from an end of the
vertical extension surface and configured to guide the air toward
the evaporator.
[0032] In this embodiment, the cool air duct may further include a
slot configured to define a passage for allowing the air flowing
along the inclined surface to flow toward the evaporator which is
provided in the rear barrier. The slot may provide an air path and
be defined in the rear barrier.
[0033] In this embodiment, the sensor may be disposed to be spaced
apart from a bottom surface of the bypass passage and the passage
cover to prevent the frost from being generated around the sensor
within the bypass passage.
[0034] The sensor may be disposed to be spaced apart from the inlet
and the outlet of the bypass passage so as to improve sensing
accuracy of the sensor and may be disposed at a point at which a
distance between the bottom wall and the cover plate is bisected in
the bypass passage.
[0035] In this embodiment, the bypass passage may be disposed so as
not to vertically overlap with the cool air inflow hole, thereby
preventing the air discharged from the outlet of the bypass passage
from being affected by the flow rate of the air introduced into the
cool air inflow hole.
[0036] In addition, the outlet of the bypass passage may be
disposed outside the limit region having a diameter greater than
that of the blower fan with respect to a center of the blower fan
provided in the cool air duct.
[0037] In this embodiment, a blocking rib may be provided above the
bypass passage in the cool air duct to prevent liquid from being
introduced into the bypass passage.
[0038] For example, the blocking rib may have a left-right minimum
length greater than a left-right minimum width of the bypass
passage, and the entire bypass passage in the left and right
direction may be disposed to overlap the blocking rib in the
vertical direction.
Advantageous Effects
[0039] According to the disclosure, since the time point at which
the defrosting is required is determined using the sensor having
the output value varying according to the amount of frost generated
on the evaporator in the bypass passage, the time point at which
the defrosting is required may be accurately determined.
[0040] In addition, according to the disclosure, since the bypass
passage vertically extend in the straight-line shape from the cool
air duct, the length of the bypass passage may be minimized.
[0041] In addition, according to the disclosure, the sensor
according to the embodiment is disposed at the point, at which the
change in flow rate is less, in the bypass passage and disposed in
the central region of the passage in the fully development flow
region.
[0042] In addition, according to the disclosure, in the
embodiments, the sensor may be disposed to be spaced apart from the
bottom surface of the bypass passage and the passage cover to
prevent the frost from being generated around the sensor.
[0043] In addition, according to the disclosure, in the
embodiments, since the passage cover includes the barrier
protruding to the outside of the bypass passage, the flow rate in
the bypass passage before the generation of the frost may be
minimized to improve the accuracy in determining of the time point,
at which the defrosting is required, through the sensor.
[0044] In addition, according to the disclosure, the blocking rib
may be provided above the bypass passage to prevent liquid from
being introduced into the bypass passage.
BRIEF DESCRIPTION OF THE DRAWINGS
[0045] FIG. 1 is a schematic longitudinal cross-sectional view of a
refrigerator according to an embodiment of the present
invention.
[0046] FIG. 2 is a perspective view of a cool air duct according to
an embodiment of the present invention.
[0047] FIG. 3 is an exploded perspective view illustrating a state
in which a passage cover and a sensor are separated from each other
in the cool air duct.
[0048] FIGS. 4(a) and 4(b) are views illustrating a flow of air in
a heat exchange space and a bypass passage before and after frost
is generated.
[0049] FIG. 5 is a schematic view illustrating a state in which a
sensor is disposed in the bypass passage.
[0050] FIG. 6 is a view of a sensor according to an embodiment of
the present invention.
[0051] FIG. 7 is a view illustrating a thermal flow around the
sensor depending on a flow of air flowing through the bypass
passage.
[0052] FIG. 8 is a view illustrating a position of the sensor in
the bypass passage.
[0053] FIG. 9 is a view illustrating an air flow pattern in the
bypass passage.
[0054] FIG. 10 is a view illustrating a flow of air in the state in
which the sensor is installed in the bypass passage.
[0055] FIG. 11 is a view illustrating an arrangement of the bypass
passage and the passage cover in the cool air duct according to an
embodiment of the present invention.
[0056] FIG. 12 is an enlarged view illustrating the bypass passage
and a rib for preventing defrosting water from being introduced
into the bypass passage according to an embodiment of the present
invention.
[0057] FIG. 13 is a view illustrating a barrier of the passage
cover according to an embodiment of the present invention.
[0058] FIG. 14 is a graph illustrating a variation in temperature
sensed by the sensor depending on a protruding length of the
barrier.
[0059] FIG. 15 is a cross-sectional view of the barrier, taken
along line A-A of FIG. 13.
[0060] FIGS. 16(a) and 16(b) are views illustrating a change in
flow of air depending on whether a slot is provided in the
barrier.
[0061] FIG. 17 is a graph illustrating a variation in temperature
sensed by the sensor depending on a length of the slot defined in
the barrier.
[0062] FIG. 18 is a view illustrating a flow of air introduced into
a heat exchange space according to an embodiment of the present
invention.
[0063] FIG. 19 is a control block diagram of the refrigerator
according to an embodiment of the present invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0064] Hereinafter, some embodiments of the present invention will
be described in detail with reference to the accompanying drawings.
Exemplary embodiments of the present invention will be described
below in more detail with reference to the accompanying drawings.
It is noted that the same or similar components in the drawings may
be designated by the same reference numerals as far as possible
even though they are shown in different drawings. Further, in
describing the embodiments of the present disclosure, when it is
determined that detailed descriptions of well-known configurations
or functions obscure the understanding of the embodiments of the
present disclosure, the detailed descriptions may be omitted.
[0065] Also, in the description of the embodiments of the present
disclosure, the terms such as first, second, A, B, (a) and (b) may
be used. Each of the terms is merely used to distinguish the
corresponding component from other components, and does not delimit
an essence, an order or a sequence of the corresponding component.
It should be understood that when one component is "connected",
"coupled" or "joined" to another component, the former may be
directly connected or jointed to the latter or may be "connected",
coupled" or "joined" to the latter with a third component
interposed therebetween.
[0066] FIG. 1 is a schematic longitudinal cross-sectional view of a
refrigerator according to an embodiment of the present invention,
FIG. 2 is a perspective view of a cool air duct according to an
embodiment of the present invention, and FIG. 3 is an exploded
perspective view illustrating a state in which a passage cover and
a sensor are separated from each other in the cool air duct.
[0067] Referring to FIGS. 1 to 3, a refrigerator 1 according to an
embodiment of the present invention may include an inner case 12
defining a storage space 11.
[0068] The storage space may include one or more of a refrigerating
storage space and a freezing storage space.
[0069] A cool air duct 20 provides a passage, through which cool
air supplied to the storage space 11 flows, in a rear space of the
storage space 11. Also, an evaporator 30 is disposed between the
cool air duct 20 and a rear wall 13 of the inner case 12. That is,
a heat exchange space 222 in which the evaporator 30 is disposed is
defined between the cool air duct 20 and the rear wall 13.
[0070] Thus, air of the storage space 11 may flow to the heat
exchange space 222 between the cool air duct 20 and the rear wall
13 of the inner case 12 and then be heat-exchanged with the
evaporator 30. Thereafter, the air may flow through the inside of
the cool air duct 20 and then be supplied to the storage space
11.
[0071] The cool air duct 20 may include, but is not limited
thereto, a first duct 210 and a second duct 220 coupled to a rear
surface of the first duct 210.
[0072] A front surface of the first duct 210 is a surface facing
the storage space 11, and a rear surface of the first duct 220 is a
surface facing the rear wall 13 of the inner case 12.
[0073] A cool air passage 212 may be provided between the first
duct 210 and the second duct 220 in a state in which the first duct
210 and the second duct 220 are coupled to each other.
[0074] Also, a cool air inflow hole 221 may be defined in the
second duct 220, and a cool air discharge hole 211 may be defined
in the first duct 210.
[0075] A blower fan (not shown) may be provided in the cool air
passage 212. Thus, when the blower fan rotates, air passing through
the evaporator 13 is introduced into the cool air passage 212
through the cool air inflow hole 221 and is discharged to the
storage space 11 through the discharge hole 211.
[0076] The evaporator 30 is disposed between the cool air duct 20
and the rear wall 13. Here, the evaporator 30 may be disposed below
the cool air inflow hole 221.
[0077] Thus, the air in the storage space 11 ascends to be
heat-exchanged with the evaporator 30 and then is introduced into
the cool air inflow hole 221.
[0078] According to this arrangement, when an amount of frost
generated on the evaporator 30 increases, an amount of air passing
through the evaporator 30 may be reduced.
[0079] In this embodiment, a time point at which defrosting for the
evaporator 30 is required may be determined using a parameter that
is changed according to the amount of frost generated on the
evaporator 30.
[0080] For example, the cool air duct 20 may further include a
frost generation sensing portion configured so that at least a
portion of the air flowing through the heat exchange space 222 is
bypassed and configured to determine a time point, at which the
defrosting is required, by using a sensor having a different output
according to a flow rate of the air.
[0081] The frost generation sensing portion may include a bypass
passage 230 bypassing at least a portion of the air flowing through
the heat exchange space 222 and a sensor 270 disposed in the bypass
passage 230.
[0082] Although not limited, the bypass passage 230 may be provided
in a recessed shape in the first duct 210. Alternatively, the
bypass passage 230 may be provided in the second duct 220.
[0083] The bypass passage 230 may be provided by recessing a
portion of the first duct 210 or the second duct 220 in a direction
away from the evaporator 30.
[0084] The bypass passage 230 may extend from the cool air duct 20
in a vertical direction.
[0085] The bypass passage 230 may be disposed to face the
evaporator 30 within a left and right width range of the evaporator
30 so that the air in the heat exchange space 222 is bypassed to
the bypass passage 230.
[0086] The frost generation sensing portion may further include a
passage cover 260 that allows the bypass passage 230 to be
partitioned from the heat exchange space 222.
[0087] The passage cover 260 may be coupled to the cool air duct 20
to cover at least a portion of the bypass passage 230 extending
vertically.
[0088] The passage cover 260 may include a cover plate 261, an
upper extension portion 262 extending upward from the cover plate
261, and a barrier 263 provided below the cover plate 261. A
specific shape of the passage cover 260 will be described later
with reference to the drawings.
[0089] FIGS. 4(a) and 4(b) are views illustrating a flow of air in
the heat exchange space and the bypass passage before and after
frost is generated.
[0090] FIG. 4(a) illustrates a flow of air before frost is
generated, and FIG. 4(b) illustrates a flow of air after frost is
generated. In this embodiment, as an example, it is assumed that a
state after a defrosting operation is completed is a state before
frost is generated.
[0091] First, referring to FIG. 4(a), in the case in which frost
does not exist on the evaporator 30, or an amount of generated
frost is remarkably small, most of the air passes through the
evaporator 30 in the heat exchange space 222 (see arrow A). On the
other hand, some of the air may flow through the bypass passage 230
(see arrow B).
[0092] Referring to FIG. 4(b), when the amount of frost generated
on the evaporator 30 is large (when defrosting is required), since
the frost on the evaporator 30 acts as flow resistance, an amount
of air flowing through the heat exchange space 222 may decrease
(see arrow C), and an amount of air flowing through the bypass
passage 230 may increase (see arrow D).
[0093] As described above, the amount (or flow rate) of air flowing
through the bypass passage 230 varies according to an amount of
frost generated on the evaporator 30.
[0094] In this embodiment, the sensor 270 may have an output value
that varies according to a change in flow rate of the air flowing
through the bypass passage 230. Thus, whether the defrosting is
required may be determined based on the change in output value.
[0095] Hereinafter, a structure and principle of the sensor 270
according to an embodiment of the present invention will be
described.
[0096] FIG. 5 is a schematic view illustrating a state in which the
sensor is disposed in the bypass passage, FIG. 6 is a view of the
sensor according to an embodiment of the present invention, and
FIG. 7 is a view illustrating a thermal flow around the sensor
depending on a flow of air flowing through the bypass passage.
Referring to FIGS. 5 to 7, the sensor 270 may be disposed at one
point in the bypass passage 230. Thus, the sensor 270 may contact
the air flowing along the bypass passage 230, and an output value
of the sensor 270 may be changed in response to a change in a flow
rate of air.
[0097] The sensor 270 may be disposed at a position spaced from
each of an inlet 231 and an outlet 232 of the bypass passage 230. A
specific location of the sensor 270 in the bypass passage 230 will
be described later with reference to the drawings.
[0098] Since the sensor 270 is disposed on the bypass passage 230,
the sensor 270 may face the evaporator 30 within the left and right
width range of the evaporator 30.
[0099] The sensor 270 may be, for example, a generated heat
temperature sensor. Particularly, the sensor 270 may include a
sensor PCB 272, a heat generating element 273 installed on the
sensor PCB 272, and a sensing element 274 installed on the sensor
PCB 272 to sense a temperature of the heat generating element
273.
[0100] The heat generating element 273 may be a resistor that
generates heat when current is applied.
[0101] The sensing element 274 may sense a temperature of the heat
generating element 273.
[0102] When a flow rate of air flowing through the bypass passage
230 is low, since a cooled amount of the heat generating element
273 by the air is small, a temperature sensed by the sensing
element 274 is high.
[0103] On the other hand, if a flow rate of the air flowing through
the bypass passage 230 is large, since the cooled amount of the
heat generating element 273 by the air flowing through the bypass
passage 230 increases, a temperature sensed by the sensing element
274 decreases.
[0104] The sensor PCB 272 may determine a difference between a
temperature sensed by the sensing element 274 in a state in which
the heat generating element 273 is turned off and a temperature by
the sensing element 274 in a state in which the heat generating
element 273 is turned on.
[0105] The sensor PCB 271 may determine whether the difference
value between the states in which the heat generating element 273
is turned on/off is less than a reference difference value.
[0106] For example, referring to FIGS. 4(a), 4(b), and 7, when an
amount of frost generated on the evaporator 30 is small, a flow
rate of air flowing to the bypass passage 230 is small. In this
case, a heat flow of the heat generating element 273 is little, and
a cooled amount of the heat generating element 273 by the air is
small.
[0107] On the other hand, when the amount of frost generated on the
evaporator 30 is large, a flow rate of air flowing to the bypass
passage 230 is large. Then, the heat flow and cooled amount of the
heat generating element 273 are large by the air flowing along the
bypass passage 230.
[0108] Thus, the temperature sensed by the sensing element 274 when
the amount of frost generated on the evaporator 30 is large is less
than that sensed by the sensing element 274 when the amount of
frost generated on the evaporator 30 is small.
[0109] Thus, in this embodiment, when the difference between the
temperature sensed by the sensing element 274 in the state in which
the heat generating element 273 is turned on and the temperature by
the sensing element 274 in the state in which the heat generating
element 273 is turned off is less than the reference temperature
difference, it may be determined that the defrosting is
required.
[0110] According to this embodiment, the sensor 270 may sense a
variation in temperature of the heat generating element 273, which
varies by the air of which a flow rate varies according to the
amount of generated frost to accurately determine a time point, at
which the defrosting is required, according to the amount of frost
generated on the evaporator 30.
[0111] The sensor 270 may further include a sensor housing 271 to
prevent the air flowing through the bypass passage 230 from
directly contacting the sensor PCB 272, the heat generating element
273, and the temperature sensor 274.
[0112] In the sensor housing 271, a wire connected to the sensor
PCB 271 is withdrawn in a state in which one side of the sensor
housing 271 is opened. Thereafter, the opened portion may be
covered by the cover portion.
[0113] The sensor housing 271 may surround the sensor PCB 272, the
heat generating element 273, and the temperature sensor 274.
[0114] FIG. 8 is a view illustrating a position of the sensor in
the bypass passage, FIG. 9 is a view illustrating an air flow
pattern in the bypass passage, and FIG. 10 is a view illustrating a
flow of air in the state in which the sensor is installed in the
bypass passage.
[0115] Referring to FIGS. 5 and 8 to 10, the passage cover 260 may
cover a portion of the bypass passage 230 in the vertical
direction.
[0116] Thus, the air may flow along a region (that is partitioned
from the heat exchange space) of the bypass passage 230, in which
the passage cover 260 substantially exists.
[0117] As described above, the sensor 270 may be disposed to be
spaced apart from the inlet 231 and the outlet 232 of the bypass
passage 230.
[0118] The sensor 270 may be disposed at a position at which the
sensor 270 is less affected by a change in flow of the air flowing
through the bypass passage 230.
[0119] For example, the sensor 270 may be disposed at a position
(hereinafter, referred to as an "inlet reference position") that is
spaced at least 6 Dg (or 6*diameter of the passage) from the inlet
(in this instance, a lower end of the passage cover 260) of the
bypass passage 230.
[0120] Alternatively, the sensor 270 may be disposed at a position
(hereinafter, referred to as an "outlet reference position") that
is spaced at least 3 Dg (or 3*diameter of the passage) from the
outlet (in this instance, an upper end of the passage cover 260) of
the bypass passage 230.
[0121] A change in flow of air is severe while the air is
introduced into the bypass passage 230 or discharged from the
bypass passage 230.
[0122] If the change in flow of air is large, it may be wrongly
determined that the defrosting is required despite a small amount
of generated frost. Thus, in this embodiment, when air flows along
the bypass passage 230, the sensor 270 is installed at a position
at which the change in flow is small to reduce detection
errors.
[0123] For example, the sensor 270 may be disposed within a range
between the inlet reference position and the outlet reference
position. The sensor 270 may be disposed closer to the outlet
reference position than the inlet reference position. Therefore,
the sensor 270 may be disposed closer to the outlet 232 than the
inlet 231 in the bypass passage 230.
[0124] Since the flow is stabilized at least at the inlet reference
position, and the flow is stabilized until the outlet reference
position, if the sensor 270 is disposed close to the outlet
reference position, the air having a stabilized flow may contact
the sensor 270.
[0125] Thus, since it is not affected other than the flow change
due to the large and small amount of generated frost, the sensing
accuracy of the sensor 270 may be improved.
[0126] Also, referring to FIG. 9, the farther away from the inlet
231 in the bypass passage 230, the air becomes a fully developed
flow form.
[0127] Since the sensor 270 is very sensitive to the change in flow
of air, when the sensor 270 is disposed at a center of the bypass
passage 230 at the point at which the fully developed flow form
occurs, the sensor 270 may accurately sense the change in flow.
[0128] Thus, as illustrated in FIG. 10, the sensor 270 may be
installed in a central region within the bypass passage 230.
[0129] Here, the central region of the bypass passage 230 is a
region including a portion at which a distance between the bottom
wall 236 of the recessed portion of the bypass passage 230 and the
passage cover 260 is bisected. That is, a portion of the sensor 270
may be disposed at a point at which the distance between the bottom
wall 236 of the recessed portion of the bypass passage 230 and the
passage cover 260 is bisected.
[0130] Referring to FIG. 10, the sensor 270 may be spaced apart
from the bottom wall 236 of the bypass passage 230 and the passage
cover 260. Thus, a portion of the air in the bypass passage 230 may
flow through a space between the bottom wall 236 and the sensor
270, and the other portion of the air may flow through a space
between the sensor 270 and the passage cover 260.
[0131] In summary, the sensor 270 should be installed in the
central region of the passage at the point at which the change in
flow of air is minimized in the bypass passage 230 and at the point
at which the fully developed flow form flows so as to improve
accuracy sensing.
[0132] Due to this arrangement, the sensor 270 may sensitively
react to the change in flow of air according to the large or small
amount of generated frost. That is, a variation in temperature
sensed by the sensor 270 may increase.
[0133] As described above, when the variation in temperature sensed
by the sensor 270 increases, it is possible to determine the time
point at which the defrosting is required even if the temperature
sensing accuracy of the sensor 270 itself is lowered.
[0134] Since the temperature sensing accuracy of the sensor itself
is related to cost, it is possible to determine the time point at
which the defrosting is required even if the sensor 270 having a
relatively low cost having low accuracy is used.
[0135] FIG. 11 is a view illustrating an arrangement of the bypass
passage and the passage cover in the cool air duct according to an
embodiment of the present invention.
[0136] Referring to FIG. 11, a lower end 260a of the passage cover
260 may be disposed at a height similar to that of a lower end of
the evaporator 30 or a height less than that of the lower end of
the evaporator 30.
[0137] According to this arrangement, when the amount of frost
generated on the evaporator 30 increases, the air may easily flow
to the bypass passage 230.
[0138] In this embodiment, since the blower fan is disposed in the
cool air duct 20, when the blower fan rotates, a portion of the air
inflow hole 221 of the cool air duct 20 may serve as a low pressure
region.
[0139] Also, since the air flows upward along the evaporator 30, a
lower side of the evaporator 30 with respect to the evaporator 30
may serve as a high pressure region, and an upper side of the
evaporator 30 with respect to the evaporator 30 may serve as a low
pressure region.
[0140] In this embodiment, the upper end 260b of the passage cover
260 may be disposed in the low pressure region.
[0141] Thus, since the lower end 260a of the passage cover 260 is
disposed in the high pressure region, and the upper end 260b is
disposed in the low pressure region, the flow of the air in the
bypass passage 230 is possible.
[0142] In addition, in this embodiment, the upper end 260b of the
passage cover 260 may be disposed higher than the evaporator 30.
Thus, the phenomenon in which the air discharged from the bypass
passage 230 is affected by the air passing through the evaporator
may be reduced.
[0143] The bypass passage 230 may be disposed so as not to
vertically overlap the air flow hole 221. This is to prevent the
air discharged from the outlet 232 of the bypass passage 230 from
being affected by the air introduced into the air flow hole
221.
[0144] Also, the outlet 232 of the bypass passage 230 may be
disposed lower than a center C of the blower fan. Also, the outlet
232 of the bypass passage 230 may be disposed lower than the lowest
point of the air flow hole 221.
[0145] In this embodiment, the air flow hole 221 has a diameter D1,
and the blower fan has a diameter D2. The diameter D2 of the blower
fan may be greater than the diameter D1 of the air flow hole
221.
[0146] A limit region having a diameter D3 greater than the
diameter D2 of the blower fan may be set based on the center C of
the blower fan, and the outlet 232 of the bypass passage 230 may be
disposed in a region outside the limit region having the diameter
D3.
[0147] Also, to minimize a length of the bypass passage 230, the
bypass passage 230 may extend vertically in a straight line shape
in the region outside the limit region.
[0148] Here, although not limited, the diameter D3 may be set to
1.5 times or more than the diameter of the blower fan.
[0149] Since the air is introduced into the cool air duct 20
through the air flow hole 221, a flow velocity in the air flow hole
221 is fast.
[0150] Also, due to the fast flow rate of the air flow hole 221,
the flow velocity of the air in the region having the diameter D3
is fast.
[0151] If the outlet 232 of the bypass passage 230 is disposed in
the limit region, there is a change in flow of air in the bypass
passage 230 due to the effect of a fast flow velocity, and thus,
the sensing accuracy of the sensor 270 is reduced.
[0152] Thus, in this embodiment, the bypass passage 230 may extend
in the straight line shape so as not to be affected by the air
having a fast flow velocity around the air flow hole 221 while
reducing the length of the bypass passage 230, and the outlet 232
may be disposed outside the limit region.
[0153] FIG. 12 is an enlarged view illustrating the bypass passage
and a rib for preventing defrosting water from being introduced
according to an embodiment of the present invention.
[0154] Referring to FIGS. 10 and 12, since the air flowing through
the bypass passage 230 contains moisture, frost may be generated in
the passage due to a capillary phenomenon in a space between the
sensor 270 and a wall defined by the bypass passage 230 in the
bypass passage 230.
[0155] Thus, in this embodiment, the sensor 270 may be spaced apart
from the bottom wall 236 of the bypass passage 230 and the passage
cover 260 to prevent the frost from being generated in the
passage.
[0156] Although not limited, the sensor 270 may be designed to be
spaced at least 1.5 mm from each of the bottom wall 236 and the
passage cover 260 (which may be referred to as a "minimum
separation distance").
[0157] Thus, a depth D of the bypass passage 230 may be equal to or
larger than a thickness of (2*the minimum separation distance) and
the sensor 270.
[0158] The left and right width W of the bypass passage 230 may be
greater than the depth D.
[0159] If the left and right width W of the bypass passage 230 are
larger than the depth D, when the air flows in the bypass passage
230, a contact area between the air and the sensor 270 increases,
and thus, the variation in temperature detected by the sensor 270
may increase.
[0160] The cool air duct 20 may be provided with a blocking rib 240
for preventing liquid such as defrosting water or moisture
generated by being melted during the defrosting process from being
introduced into the bypass passage 230.
[0161] The blocking rib 240 may be disposed above the outlet 232 of
the bypass passage 230. The blocking rib 240 may have a protrusion
shape protruding from the cool air duct 20.
[0162] The blocking rib 240 may allow the dropping liquid to be
spread horizontally so as to prevent the liquid from being
introduced into the bypass passage 230.
[0163] The blocking rib 240 may be provided horizontally in a
straight line shape or be provided in a rounded shape to be convex
upward.
[0164] The blocking rib 240 may be disposed to overlap with the
entire left and right side of the bypass passage 230 in the
vertical direction and may have a minimum left and right length
greater than the right and left width of the bypass passage
230.
[0165] When the blocking rib 240 is provided in the cool air duct
20, since the blocking rib 240 serves as flow resistance of air,
the minimum left and right length of the blocking rib 240 may be
set to two times or less of the right and left width W.
[0166] As the blocking rib 240 is disposed closer to the bypass
passage 230, the length of the blocking rib 240 may be shortened.
On the other hand, the defrosting water may flow over the blocking
rib 240 and then be introduced into the bypass passage 230.
[0167] Thus, the blocking rib 240 may be spaced apart from the
bypass passage 230 in the vertical direction, and the maximum
separation distance may be set within a range of the right and left
width W of the bypass passage 230.
[0168] The cool air duct 20 may further include a sensor
installation groove 235 recessed to install the sensor 270.
[0169] The cool air duct 20 may include a bottom wall 236 and both
sidewalls 233 and 234 for providing the bypass passage 230, and the
sensor installation groove 235 may be recessed in one or more of
both the sidewalls 233 and 234.
[0170] In the state in which the sensor 270 is installed in the
sensor installation groove 235, the sensor 270 may be spaced at the
minimum separation distance from the bottom wall 236 and the
passage cover 260 as described above.
[0171] FIG. 13 is a view illustrating a barrier of the passage
cover according to an embodiment of the present invention, FIG. 14
is a graph illustrating a variation in temperature sensed by the
sensor depending on a protruding length of the barrier, and FIG. 15
is a cross-sectional view of the barrier, taken along line A-A of
FIG. 13.
[0172] FIGS. 16(a) and 16(b) are views illustrating a change in
flow of air depending on whether a slot is provided in the barrier,
and FIG. 17 is a graph illustrating a variation in temperature
sensed by the sensor depending on a length of the slot defined in
the barrier.
[0173] FIG. 18 is a view illustrating a flow of air introduced into
the heat exchange space according to an embodiment of the present
invention.
[0174] Referring to FIGS. 3, 8, and 12 to 18, the passage cover 260
may include a cover plate 261, an upper extension portion 262 and a
barrier 263.
[0175] The cover plate 261 may cover the bypass passage 230 and may
be provided in a thin plate shape. For example, the cover plate 261
may cover the bypass passage 230 in a state of being spaced apart
from the bottom wall 236.
[0176] A seating groove 235a for seating the cover plate 261 may be
defined vertically in the cool air duct 20. When the cover plate
261 is seated in the seating groove 235a, an outer surface of the
cover plate 261 may provide a substantially continuous surface with
respect to the cool air duct 20.
[0177] The upper extension portion 262 may also cover a portion of
the bypass passage 230 and extend to be inclined at a predetermined
angle from the cover plate 261.
[0178] The upper extension portion 262 is configured to extend to
be inclined from the cover plate 261 corresponding to a portion
(226: hereinafter, referred to as an "upper inclined portion") of
the cool air duct 20.
[0179] If the cool air duct 20 does not include an upper inclined
portion, the upper extension portion 262 may be omitted, and the
cover plate 261 may be provided in the straight line shape.
[0180] The upper extension portion 262 covers only a portion of the
bypass passage 230. Thus, a portion of the bypass passage 230 is
exposed to the outside to be the outlet 232.
[0181] A portion of the barrier 263 is disposed outside the bypass
passage 230 while the cover plate 261 covers the bypass passage
230. For example, the barrier 263 may protrude downward from upper
and lower extension surfaces 227 of the cool air duct 20.
[0182] Thus, one portion of the barrier 263 is disposed in the
bypass passage 230, and the other portion protrudes downward from
the bypass passage 230.
[0183] Specifically, the barrier 263 includes a rear barrier 267
disposed close to the evaporator 30, a front barrier 264 spaced
forward from the rear barrier 267, and a plurality of side barriers
265 and 266 connecting the front barrier 264 to the rear barrier
267. The plurality of side barriers 265 and 266 may be spaced apart
from each other in the left-right direction. Although not limited,
the plurality of side barriers 265 and 266 may be disposed in
parallel to each other.
[0184] The rear barrier 267 is a wall provided to be continuous
with the cover plate 261. The plurality of side barriers 265 and
266 are walls extending forward from the rear barrier 267. The
front barrier 264 is a wall connecting front ends of the plurality
of side barriers 265 and 266 to each other.
[0185] The front barrier 264 is disposed at an opposite side of the
evaporator 30 with respect to the rear barrier 267.
[0186] Then, a bottom surface of the barrier 263 is opened. Thus, a
guide passage 268 for guiding air to the bypass passage 230 is
provided by the front barrier 264, the plurality of side barriers
265 and 266, and the rear barrier 267.
[0187] The guide passage 268 is a passage communicating with the
bypass passage 230 at the outside of the bypass passage 230. The
guide passage 268 also serves as the bypass passage.
[0188] In the cool air duct 20, a vertical extension surface 227 in
which the bypass passage 230 is provided may be a substantially
vertical surface.
[0189] The bypass passage 230 may extend vertically in a straight
line shape from the vertical extension surface 227.
[0190] The cool air duct 20 may further include an inclined surface
228 extending from a lower end of the vertical extension surface
227. The inclined surface 228 may extend downward as a distance
from the evaporator 30 increases.
[0191] The inclined surface 228 is a surface that guides the air in
the storage space 11 to the heat exchange space 222.
[0192] Thus, the air in the storage space 11 may flow to be
inclined upward by the inclined surface 228 when viewed from a side
surface of the heat exchange space 222.
[0193] In this embodiment, the barrier 263 may serve to limit an
introduction of the air flowing to the heat exchange space 222 into
the bypass passage 230 when an amount of frost generated on the
evaporator 30 is small.
[0194] On the other hand, the barrier 230 may serve to effectively
guide the air introduced into the heat exchange space 222 to the
bypass passage 230 when an amount of frost generated on the
evaporator 30 is large.
[0195] As described above, when the change in flow rate of the air
increases due to the large and small amount of frost generated on
the evaporator 30, the sensing accuracy of the sensor 270 may be
improved by the barrier 263.
[0196] That is, if the change in flow rate of the air is large due
to the large and small amount of frost generated on the evaporator
30, the variation in temperature sensed by the sensor 270 is large,
and thus, the time point at which the defrosting is required may be
accurately determined.
[0197] In addition, as described above, when the variation in
temperature sensed by the sensor 270 increases due to the large and
small amount of frost generated on the evaporator 30, even when the
sensor 270 having low sensor accuracy is used, the time point at
which the defrosting is required may be determined.
[0198] In this embodiment, a flow rate of air introduced into the
bypass passage 230 may vary according to a length of the barrier
263 protruding from the lower end (that is a boundary between the
vertical extension surface 227 and the inclined surface 228) of the
vertical extension surface 227.
[0199] Referring to FIG. 14, a horizontal axis represents the
protruding length of the barrier, and a vertical axis represents
the variation in temperature before and after the frost
generation.
[0200] When the protruding length of the barrier 263 is short, the
flow rate of the air flowing through the bypass passage 230
increases even before the frost generation.
[0201] When the flow rate of the air flowing through the bypass
passage 230 is large before the frost generation, the variation in
temperature sensed by the sensor 270 (for example, a difference
value between the highest temperature and the lowest temperature)
is large. Thus, the flow rate of the air flowing through the bypass
passage 230 is large even after the frost generation, and the
variation in temperature sensed by the sensor 270 is large.
[0202] As a result, the variation between the temperature sensed by
the sensor 270 before the frost generation and the temperature
sensed by the sensor 270 after the frost generation (for example,
the difference between the lowest temperature before the frost
generation and the lowest temperature after the frost generation)
decreases.
[0203] On the other hand, when the protruding length of the barrier
263 increases, the flow rate of the air flowing through the bypass
passage 230 before the frost generation decreases. The variation in
temperature sensed by the sensor 270 before the frost generation
decreases.
[0204] On the other hand, since the variation in temperature sensed
by the sensor 270 is large after the frost generation, the
variation between the temperature sensed by the sensor 270 before
the frost generation and the temperature sensed by the sensor 270
after the frost generation increases.
[0205] However, when the protruding length of the barrier 263 is
too long, the flow rate of the air flowing into the bypass passage
230 decreases before and after the frost generation. As a result,
the variation between the temperature sensed by the sensor 270
before the frost generation and the temperature sensed by the
sensor 270 after the frost generation decreases.
[0206] Accordingly, the protrusion length of the barrier 230 may be
set to a value ranging of about 10 mm to about 17 mm so that the
variation in temperature sensed by the sensor 270 before and after
the frost generation is greater than the reference variation.
[0207] The lower end of the barrier 263 may be horizontally
disposed. For example, the front barrier 264 and the plurality of
side barriers 265 and 266 may be disposed on substantially the same
horizontal plane.
[0208] In this case, as illustrated in FIG. 16(a), since the air in
the storage space 11 flows upward along the inclined surface 228,
when the air, which passes through the front barrier 264, that
flows to be inclined collides with the rear barrier 267, the air
flows to the bypass passage 230 without flowing to the evaporator
30.
[0209] In this case, the flow rate of the air flowing into the
bypass passage 230 increases regardless of the amount of generated
frost.
[0210] In the case of this embodiment, the accuracy of determining
the time point at which the defrosting is required may be improved
when the flow rate of the air flowing through the bypass passage
230 is minimized before the frost generation.
[0211] Thus, a slot 269 providing a flow path of air may be defined
in the rear barrier 267 so that the air passing through the lower
end of the front barrier 264 flows directly to the evaporator
30.
[0212] When the slot 269 is defined in the rear barrier 267 as
illustrated in FIG. 16(b), the air passing through the lower end of
the front barrier 264 may not collide with the rear barrier 267,
and thus may not directly flow to the bypass passage 230.
[0213] In this embodiment, the air colliding with the front barrier
264 flows along the plurality of side barriers 265 and 266 and then
flows toward the rear barrier 267.
[0214] When the slot 269 is not defined in the rear barrier 267,
the air flowing along the side barriers 265 and 266 does not flow
to the evaporator 30 but flows to the bypass passage 230.
[0215] On the other hand, when the slot 269 is defined in the rear
barrier 267, the air flowing along the side barriers 265 and 266
flows to the evaporator 30 by the slot 269.
[0216] Thus, in this embodiment, the flow rate of the air flowing
to the bypass passage 230 may be determined actually by the flow
rate of the air directly introduced into the guide passage 268 of
at least the barrier 263 and the flow rate of the air introduced
into the barrier 263 along the slot 269 after flowing along a
circumference of the barrier 263.
[0217] In this embodiment, if a length of the slot 269 (a height
from the lower end of the barrier 262) is small, the flow rate of
the air flowing into the bypass passage 230 is large, and when the
slot 269 increases in length, the flow rate of the air flowing into
the bypass passage 230 is reduced.
[0218] However, if the length of the slot 269 is too long, the flow
rate of the air flowing through the slot 269 after flowing along
the side barriers 265 and 266 increases, and even before the frost
generation, the flow rate of the air flowing into the bypass
passage 230 increases.
[0219] Thus, in this embodiment, the length of the slot may be set
to a value ranging of about 4 mm to about 9 mm so that the flow
rate of the air flowing into the bypass passage 230 is minimized
before the frost generation. Although not limited, the length of
the slot 269 may be designed within a range of about 1/5 to about
1/2 of the protruding length of the barrier 263.
[0220] FIG. 19 is a control block diagram of the refrigerator
according to an embodiment of the present invention.
[0221] Referring to FIG. 19, the refrigerator 1 according to an
embodiment of the present invention may further include a defroster
50 operating to defrost the evaporator 30 and a controller 40
controlling the defroster 50. The controller may be an electronic
processor.
[0222] The defroster 50 may include, for example, a heater. When
the heater is turned on, heat generated by the heater is
transferred to the evaporator 30 to melt frost generated on the
surface of the evaporator 30.
[0223] The controller 40 may control the heat generating element
273 of the sensor 270 so as to be turned on with a regular
cycle.
[0224] To determine the time point at which the defrosting is
required, the heat generating element 273 may be maintained in the
turn-on state for a certain time, and a temperature of the heat
generating element 273 may be sensed by the sensing element
274.
[0225] After the heat generating element 273 is turned on for the
certain time, the heat generating element 274 may be turned off,
and the sensing element 274 may sense the temperature of the turned
off heat generating element 274. Also, the sensor PCB 272 may
determine whether a maximum value of the temperature difference
value in the turn on/off state of the heat generating element 273
is equal to or less than the reference difference value.
[0226] Then, when the maximum value of the temperature difference
value in the turn on/off state of the heat generating element 273
is equal to or less than the reference difference value, it is
determined that defrosting is required. Thus, the defroster 50 may
be turned on by the controller 40.
[0227] In the above, it has been described as determining whether
the temperature difference value of the turn on/off state of the
heat generating element 273 in the sensor PCB 272 is equal to or
less than the reference difference value. On the other hand, the
controller 40 may determine whether the temperature difference
value in the turn on/off state of the heat generating element 273
is equal to or less than the reference difference value and then
control the defroster 50 according to the determination result.
* * * * *