U.S. patent application number 15/439462 was filed with the patent office on 2018-08-23 for system and method for minimizing air leak in an hvac unit.
This patent application is currently assigned to DENSO International America, Inc.. The applicant listed for this patent is DENSO International America, Inc.. Invention is credited to Reilly Patrick MULLETT, James STANDER.
Application Number | 20180236846 15/439462 |
Document ID | / |
Family ID | 63166908 |
Filed Date | 2018-08-23 |
United States Patent
Application |
20180236846 |
Kind Code |
A1 |
STANDER; James ; et
al. |
August 23, 2018 |
SYSTEM AND METHOD FOR MINIMIZING AIR LEAK IN AN HVAC UNIT
Abstract
A heating, ventilation, and air condition (HVAC) unit may
include a casing, an evaporator, a heater core, and a first damper.
The casing may define a front airflow passageway, a rear airflow
passageway having an inlet, and first and second outlets in fluid
communication with the rear airflow passageway. The evaporator and
the heater core may be disposed within the casing. The first damper
may be disposed within the casing between the evaporator and the
heater core and movable between a first position in which airflow
is directed to the heater core and a second position in which
airflow is directed away from the heater core. Airflow across the
evaporator from the front airflow passageway to the rear airflow
passageway is directed to the first and second outlets when the
first damper is moved from the first position toward the second
position.
Inventors: |
STANDER; James; (West
Bloomfield, MI) ; MULLETT; Reilly Patrick; (Livonia,
MI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DENSO International America, Inc. |
Southfield |
MI |
US |
|
|
Assignee: |
DENSO International America,
Inc.
Southfield
MI
|
Family ID: |
63166908 |
Appl. No.: |
15/439462 |
Filed: |
February 22, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B60H 1/0005 20130101;
B60H 1/00521 20130101; B60H 1/00464 20130101; B60H 1/00564
20130101; B60H 1/00064 20130101; B60H 1/00864 20130101; B60H
2001/00099 20130101; B60H 2001/002 20130101; B60H 1/00978
20130101 |
International
Class: |
B60H 1/00 20060101
B60H001/00 |
Claims
1. A heating, ventilation, and air conditioning (HVAC) unit
comprising: a casing defining a front airflow passageway, a rear
airflow passageway and first and second outlets, the rear airflow
passageway having an inlet, the first and second outlets fluidly
coupled with the rear airflow passageway; an evaporator disposed
within the casing such that a first section of the evaporator is
disposed in the front airflow passageway and a second section of
the evaporator is disposed in the rear airflow passageway; a heater
core disposed within the casing such that a first section of the
heater core is disposed in the front airflow passageway and a
second section of the heater core is disposed in the rear airflow
passageway; a first damper disposed within the casing between the
evaporator and the heater core, the first damper movable between a
first position in which airflow is directed to the second section
of the heater core and a second position in which airflow is
directed away from the second section of the heater core; a first
blower unit configured to blow air through the front airflow
passageway; a second blower unit configured to blow air through the
rear airflow passageway; and a controller operatively connected to
the first damper, the first blower unit and the second blower unit,
wherein the controller moves the first damper from the first
position toward the second position when the first blower unit is
in an ON mode and the second blower unit is in an OFF mode, wherein
airflow across the evaporator from the front airflow passageway to
the rear airflow passageway is directed to the first and second
outlets when the first damper is moved from the first position
toward the second position.
2. The HVAC unit of claim 1, wherein the first damper controls
airflow through the rear airflow passageway.
3.-5. (canceled)
6. The HVAC unit of claim 2, wherein the first damper reduces the
airflow from the front airflow passageway from flowing across the
evaporator to the inlet of the rear airflow passageway.
7. The HVAC unit of claim 6, further comprising a second damper
disposed within the casing downstream of the heater core, and
wherein the second damper is movable between a first position and a
second position.
8. The HVAC unit of claim 7, wherein the second damper is moved to
an intermediate position to distribute the airflow from the front
airflow passageway to the rear airflow passageway out the first and
second outlets.
9. A heating, ventilation, and air conditioning (HVAC) unit
comprising: a casing defining a front airflow passageway, a rear
airflow passageway and first and second outlets, the rear airflow
passageway having an inlet, the first and second outlets fluidly
coupled with the rear airflow passageway; an evaporator disposed
within the casing such that a first section of the evaporator is
disposed in the front airflow passageway and a second section of
the evaporator is disposed in the rear airflow passageway; a heater
core disposed within the casing such that a first section of the
heater core is disposed in the front airflow passageway and a
second section of the heater core is disposed in the rear airflow
passageway; a first damper disposed within the casing between the
evaporator and the heater core, the first damper movable between a
first position in which airflow is directed to the second section
of the heater core and a second position in which airflow is
directed away from the second section of the heater core; a first
blower unit configured to blow air through the front airflow
passageway; a second blower unit configured to blow air through the
rear airflow passageway; and a controller operatively connected to
the first damper, the first blower unit and the second blower unit,
wherein the controller moves the first damper from the first
position toward the second position when the first blower unit is
in an ON mode and the second blower unit is in an OFF mode, wherein
moving the first damper from the first position toward the second
position reduces airflow across the evaporator from the front
airflow passageway from flowing across the evaporator to the inlet
of the rear airflow passageway.
10. The HVAC unit of claim 9, wherein the first damper controls
airflow through the rear airflow passageway.
11-13. (canceled)
14. The HVAC unit of claim 10, wherein the airflow from the front
airflow passageway to the rear airflow passageway is directed to
the first and second outlets when the first damper is moved from
the first position toward the second position.
15. The HVAC unit of claim 14, further comprising a second damper
disposed within the casing downstream of the heater core, and
wherein the second damper is movable between a first position and a
second position.
16. The HVAC unit of claim 15, wherein the second damper is moved
to an intermediate position to distribute the airflow from the
front airflow passageway to the rear airflow passageway out of the
first and second outlets.
17-19. (canceled)
Description
FIELD
[0001] The present disclosure relates to systems and methods for
minimizing an air leak in an HVAC unit and, in particular, to
systems and methods for minimizing a front to rear air leak in an
integrated HVAC unit.
BACKGROUND
[0002] This section provides background information related to the
present disclosure, which is not necessarily prior art.
[0003] HVAC (heating, ventilation, and air conditioning) units
provide airflow (heated and/or cooled) to a front region and a rear
region of a vehicle cabin, for example. In some instances, airflow
may only be desired in the front region of the vehicle cabin, and
therefore, airflow to the rear region is terminated. Providing
airflow to the front region of the vehicle while terminating
airflow to the rear region of the vehicle can cause undesirable air
leakage to the vehicle cabin which is discomforting to the vehicle
occupants.
[0004] The HVAC unit of the present disclosure restricts air
leakage into the vehicle cabin, and therefore, avoids vehicle
occupant discomfort.
SUMMARY
[0005] This section provides a general summary of the disclosure,
and is not a comprehensive disclosure of its full scope or all of
its features.
[0006] In one form, a heating, ventilation, and air conditioning
(HVAC) unit includes a casing, an evaporator, a heater core, and a
first damper. The casing defines a front airflow passageway, a rear
airflow passageway having an inlet, and first and second outlets.
The first and second outlets are in fluid communication with the
rear airflow passageway. The evaporator is disposed within the
casing such that a first section of the evaporator is disposed in
the front airflow passageway and a second section of the evaporator
is disposed in the rear airflow passageway. The heater core is
disposed within the casing such that a first section of the heater
core is disposed in the front airflow passageway and a second
section of the heater core is disposed in the rear airflow
passageway. The first damper is disposed within the casing between
the evaporator and the heater core and is moveable between a first
position in which airflow is directed to the second section of the
heater core and a second position in which airflow is directed away
from the second section of the heater core. Airflow across the
evaporator from the front airflow passageway to the rear airflow
passageway is directed to the first and second outlets when the
first damper is moved from the first position toward the second
position.
[0007] In some configurations, the first damper controls airflow
through the rear airflow passageway.
[0008] In some configurations, a first blower unit is configured to
blow air to the front airflow passageway.
[0009] In some configurations, a second blowerunit is configured to
blow air to the second airflow passageway.
[0010] In some configurations, the first blower unit is in an ON
mode and a second blower unit is in an OFF mode when the first
damper is moved toward the second position and the airflow from the
front airflow passageway to the rear airflow passageway is directed
toward the first and second outlets.
[0011] In some configurations, the first damper reduces the airflow
from the front airflow passageway to the rear airflow passageway
from flowing to the inlet of the rear airflow passageway.
[0012] In some configurations, a second damper is disposed within
the casing downstream of the heater core and movable between a
first position and a second position.
[0013] In some configurations, the second damper is moved to an
intermediate position to distribute the airflow from the front
airflow passageway to the rear airflow passageway out the first and
second outlets.
[0014] In another form, a heating, ventilation, and air
conditioning (HVAC) unit includes a casing, an evaporator, a heater
core, and a first damper. The casing defines a front airflow
passageway, a rear airflow passageway having an inlet, and first
and second outlets in fluid communication with the rear airflow
passageway. The evaporator is disposed within the casing such that
a first section of the evaporator is disposed in the front airflow
passageway and a second section of the evaporator is disposed in
the rear airflow passageway. The heater core is disposed within the
casing such that a first section of the heater core is disposed in
the front airflow passageway and a second section of the heater
core is disposed in the rear airflow passageway. The first damper
is disposed within the casing between the evaporator and the heater
core and is moveable between a first position in which airflow is
directed to the second section of the heater core and a second
position in which airflow is directed away from the second section
of the heater core. Moving the first damper from the first position
toward the second position reduces airflow across the evaporator
from the front airflow passageway to the rear airflow passageway
from flowing to the inlet of the rear airflow passageway.
[0015] In some configurations, the first blower unit is in an ON
mode and the second blower unit is in an OFF mode when the first
damper reduces the airflow from the front airflow passageway to the
rear airflow passageway from flowing to the inlet of the rear
airflow passageway.
[0016] In some configurations, the airflow from the front airflow
passageway to the rear airflow passageway is directed to the first
and second outlets when the first damper is moved from the first
position toward the second position.
[0017] In yet another form, the present disclosure provides a
method for reducing air leakage through an inlet of the rear
airflow passageway of an HVAC unit. The method includes turning a
first blower unit configured to blow air to the front airflow
passageway of a casing of the HVAC unit to an ON mode; turning a
second blower unit configured to blow air to the rear airflow
passageway of the casing of the HVAC unit to an OFF mode; and
moving a first damper disposed between an evaporator and a heater
core within the casing from a first position toward a second
position such that the first damper reduces airflow across the
evaporator from the front airflow passageway to the rear airflow
passageway from flowing to a first inlet of the rear airflow
passageway.
[0018] In some configurations, the airflow from the front airflow
passageway to the rear airflow passageway is directed to first and
second outlets of the rear airflow passageway when the first damper
is moved from the first position toward the second position.
[0019] In some configurations, the method includes moving a second
damper disposed downstream of the heater core to an intermediate
position such that the airflow is distributed between the first and
second outlets of the rear airflow passageway.
[0020] Further areas of applicability will become apparent from the
description provided herein. The description and specific examples
in this summary are intended for purposes of illustration only and
are not intended to limit the scope of the present disclosure.
DRAWINGS
[0021] The drawings described herein are for illustrative purposes
only of selected embodiments and not all possible implementations,
and are not intended to limit the scope of the present
disclosure.
[0022] FIG. 1 is a representative vehicle including a heating,
ventilation, and air conditioning (HVAC) unit in accordance with
the present teachings;
[0023] FIG. 2 is a perspective view of the HVAC unit of FIG. 1;
[0024] FIG. 3 is a back view of the HVAC unit of FIG. 1;
[0025] FIG. 4 is a cross-section view of the HVAC unit of FIG. 1;
and
[0026] FIG. 5 is a flowchart of a control sequence of the HVAC
unit.
[0027] Corresponding reference numerals indicate corresponding
parts throughout the several views of the drawings.
DETAILED DESCRIPTION
[0028] Example embodiments will now be described more fully with
reference to the accompanying drawings.
[0029] The foregoing description of the embodiments has been
provided for purposes of illustration and description. It is not
intended to be exhaustive or to limit the disclosure. Individual
elements or features of a particular embodiment are generally not
limited to that particular embodiment, but, where applicable; are
interchangeable and can be used in a selected embodiment, even if
not specifically shown or described. The same may also be varied in
many ways. Such variations are not to be regarded as a departure
from the disclosure, and all such modifications are intended to be
included within the scope of the disclosure.
[0030] Example embodiments are provided so that this disclosure
will be thorough, and will fully convey the scope to those who are
skilled in the art. Numerous specific details are set forth such as
examples of specific components, devices, and methods, to provide a
thorough understanding of embodiments of the present disclosure. It
will be apparent to those skilled in the art that specific details
need not be employed, that example embodiments may be embodied in
many different forms and that neither should be construed to limit
the scope of the disclosure. In some example embodiments,
well-known processes, well-known device structures, and well-known
technologies are not described in detail.
[0031] The terminology used herein is for the purpose of describing
particular example embodiments only and is not intended to be
limiting. As used herein, the singular forms, "an," and "the" may
be intended to include the plural forms as well, unless the context
clearly indicates otherwise. The terms "comprises," "comprising,"
"including," and "having," are inclusive and therefore specify the
presence of stated features, integers, steps, operations, elements,
and/or components, but do not preclude the presence or addition of
one or more other features, integers, steps, operations, elements,
components, and/or groups thereof. The method steps, processes, and
operations described herein are not to be construed as necessarily
requiring their performance in the particular order discussed or
illustrated, unless specifically identified as an order of
performance. It is also to be understood that additional or
alternative steps may be employed.
[0032] When an element or layer is referred to as being "on,"
"engaged to," "connected to," or "coupled to" another element or
layer, it may be directly on, engaged, connected or coupled to the
other element or layer, or intervening elements or layers may be
present. In contrast, when an element is referred to as being
"directly on," "directly engaged to," "directly connected to," or
"directly coupled to" another element or layer, there may be no
intervening elements or layers present. Other words used to
describe the relationship between elements should be interpreted in
a like fashion (e.g., "between" versus "directly between,"
"adjacent" versus "directly adjacent," etc.). As used herein, the
term "and/or" includes any and all combinations of one or more of
the associated listed items.
[0033] Although the terms first, second, third, etc. may be used
herein to describe various elements, components, regions, layers
and/or sections, these elements, components, regions, layers and/or
sections should not be limited by these terms. These terms may be
only used to distinguish one element, component, region, layer or
section from another region, layer or section. Terms such as
"first," "second," and other numerical terms when used herein do
not imply a sequence or order unless clearly indicated by the
context. Thus, a first element, component, region, layer or section
discussed below could be termed a second element, component,
region, layer or section without departing from the teachings of
the example embodiments.
[0034] Spatially relative terms, such as "inner," "outer,"
"beneath," "below," "lower," "above," "upper," and the like, may be
used herein for ease of description to describe one element or
feature's relationship to another element(s) or feature(s) as
illustrated in the figures. Spatially relative terms may be
intended to encompass different orientations of the device in use
or operation in addition to the orientation depicted in the
figures. For example, if the device in the figures is turned over,
elements described as "below" or "beneath" other elements or
features would then be oriented "above" the other elements or
features. Thus, the example term "below" can encompass both an
orientation of above and below. The device may be otherwise
oriented (rotated 90 degrees or at other orientations) and the
spatially relative descriptors used herein interpreted
accordingly.
[0035] FIG. 1 illustrates a vehicle 10 having a heating, venting,
and air cooling (HVAC) unit 12 disposed in a front portion 14
thereof. The HVAC unit 12 may provide airflow (heated and/or
cooled) to a front region 16 of a vehicle cabin 18 via a front set
of duct lines (not shown) and a rear region 20 of the vehicle cabin
18 via a rear set of duct lines (not shown). With additional
reference to FIGS. 2-4, the HVAC unit 12 may include a casing 22, a
rear blower unit 24, a front blower unit 26, a front damper
assembly 28 and a rear damper assembly 30. A controller 31 (FIG. 1)
may control the HVAC unit 12. That is, the controller 31 may
determine HVAC inputs from a user through a user interface (not
shown) and may control various components of the HVAC unit 12 such
as the rear blower unit 24, the front blower unit 26, the front
damper assembly 28, and the rear damper assembly 30.
[0036] The casing 22 may include a first shell 32, a second shell
34 and an evaporator housing 35. The first shell 32, the second
shell 34, and the evaporator housing 35 may be formed of a molded
plastic material, such as a thermoplastic for example, and can be
joined together by any suitable method, including plastic welding,
and/or clips for example. The first shell 32, the second shell 34
and the evaporator housing 35 may define a front airflow passageway
36, a rear airflow passageway 38, a plurality of front outlets 40
and a plurality of rear outlets 41. An evaporator 42 may be
disposed within the evaporator housing 35 of the casing 22 such
that a first section 42a is disposed in the front airflow
passageway 36 and a second section 42b is disposed in the rear
airflow passageway 38. The evaporator 42 may be any suitable type
of heat exchanger such as a plate-fin heat exchanger or a
shell-tube heat exchanger, for example, configured to remove heat
from air flowing across or through the evaporator 42. Additionally,
a heater core 44 may be disposed within the first and second shells
32, 34 of the casing 22 such that a first section 44a is disposed
in the front airflow passageway 36 and a second section 44b is
disposed in the rear airflow passageway 38. The heater core 44 can
be any suitable type of heat exchanger, such as a plate-fin heat
exchanger or shell-tube exchanger, for example, configured to add
heat to the air flowing across or through the heater core 44.
[0037] The front airflow passageway 36 may include a front supply
flue 46, a front cool flue 48, and a front heat flue 49. The front
supply flue 46 may be located upstream of the evaporator 42 and may
fluidly couple the front blower unit 26 and the evaporator 42. The
front cool flue 48 is located downstream of the evaporator 42 and
upstream of the heater core 44. That is, the front cool flue 48 is
located between the evaporator 42 and the heater core 44 so as to
fluidly couple the evaporator 42 and heater core 44. Airflow
passing though the evaporator 42 from the supply flue 46 may be
cooled as it enters into the front cool flue 48. The front heat
flue 49 is located downstream of the heater core 44 and may fluidly
couple the heater core 44 and the front outlets 40. Airflow passing
through the heater core 44 from the front cool flue 48 may be
heated as it enters into the front heat flue 49.
[0038] The rear airflow passageway 38 may include an inlet or rear
supply flue 50, a rear cool flue 52, a rear heat flue 54, and a
rear mix flue 55. The rear supply flue 50 may be located upstream
of the evaporator 42 and may fluidly couple the rear blower unit 24
and the evaporator 42. The rear cool flue 52 is located downstream
of the evaporator 42 and upstream of the heater core 44. That is,
the rear cool flue 52 is located between the evaporator 42 and the
heater core 44 so as to fluidly couple the evaporator 42 and heater
core 44. Airflow passing though the evaporator 42 from the rear
supply flue 50 may be cooled as it enters into the rear cool flue
52. The rear heat flue 54 is located downstream of the heater core
44 and may fluidly couple the heater core 44 and the rear mix flue
55. Airflow passing through the heater core 44 from the rear cool
flue 52 may be heated as it enters into the rear heat flue 54. The
rear mix flue 55 is located upstream of the rear outlets 41 and may
fluidly couple the rear cool flue 52 and/or the rear heat flue 54
to the rear outlets 41.
[0039] The plurality of front outlets 40 may be in fluid
communication with the front region 16 of the of the vehicle cabin
18. The plurality of front outlets 40 may also be fluidly coupled
with the front heat flue 49 of the front airflow passageway 36 and
may include a vent outlet 40a, a defrost outlet 40b, and a foot
well outlet 40c (FIG. 4). The vent, defrost and foot well outlets
40a, 40b, 40c may be positioned adjacent to each other at an upper
end 56 of the casing 22. Airflow passing through the front airflow
passageway 36 may exit out of one or more of the vent, defrost, and
foot well outlets 40a, 40b, 40c.
[0040] The plurality of rear outlets 41 may be in fluid
communication with the rear region 20 of the of the vehicle cabin
18. The plurality of rear outlets 41 may also be fluidly coupled
with the rear mix flue 55 of the rear airflow passageway 38 and may
include a rear vent outlet 41a and a rear foot well outlet 41b
(FIG. 4). The vent outlet 41a and foot well outlet 41b may be
positioned adjacent to each other at the lower end 58 of the casing
22. Airflow passing through the rear airflow passageway 38 may exit
out of one or both of the vent outlet 41a and foot well outlet
41b.
[0041] The rear blower unit 24 may be fluidly coupled to the rear
supply flue 50 and configured to blow air to the rear supply flue
50. The rear blower unit 24 includes a blower housing 60, a rear
blower fan 62 and a rear blower motor (not shown). The blower
housing 60 defines a rear air inlet 64 that may be in fluid
communication with the vehicle cabin 18 and the rear supply flue
50. The rear blower fan 62 is disposed within the blower housing
60. The rear blower motor (not shown) may be drivingly coupled to
the rear blower fan 62 and operable in an ON-OFF mode. When the
rear blower motor (not shown) is in the ON mode, the rear blower
motor rotates the rear blower fan 62 to draw air through the rear
air inlet 64 from the vehicle cabin 18 and into the rear supply
flue 50. In some configurations, air can be drawn through the rear
air inlet 64 from an exterior of the vehicle 10, in addition to, or
instead of, the vehicle cabin 18.
[0042] The front blower unit 26 is fluidly coupled with the front
supply flue 46 and configured to blow air to the front supply flue
46. The front blower unit 26 includes a front blower housing 66, an
inlet duct 68 and an outlet duct 70. The front blower housing 66 is
coupled to the inlet duct 68 at one side 72 and coupled to the
outlet duct 70 at another side 74 (FIG. 3). A front blowerfan (not
shown) is disposed within the front blower housing 66. A front
blower motor (not shown) may be drivingly coupled to the front
blower fan (not shown) and operable in an ON-OFF mode. When the
front blower motor is in the ON mode, the front blower motor
rotates the front blower fan to draw air through the inlet duct 68
and into the front supply flue 46 via the front blower housing 66
and the outlet duct 70.
[0043] The inlet duct 68 includes a first air inlet 76 fluidly
coupled with the exterior of the vehicle 10 and/or the HVAC unit
12, a second air inlet 78 fluidly coupled with the vehicle cabin
18, and a third air inlet 79 fluidly coupled with the exterior of
the vehicle 10 and/or HVAC unit 12. When the front blower motor
(not shown) rotates the front blower fan (not shown), air may be
drawn in from the exterior of the vehicle 10 and/or the HVAC unit
12 through the first and third air inlets 76, 79 and into the front
supply flue 46. Alternatively or additionally, air may be drawn
through the second air inlet 78 from the vehicle cabin 18 and into
the front supply flue 46.
[0044] The front damper assembly 28 is disposed within the casing
22 proximate to the plurality of front outlets 40 (FIG. 4). The
front damper assembly 28 includes a first damper 80 and a second
damper 82. The first damper 80 is pivotally attached to the casing
22 and movable between a first position and a second position. When
the first damper 80 is in the first position (shown in FIG. 4),
airflow may exit the casing 22 through the defrost outlet 40b. When
the first damper 80 is in the second position (shown in phantom
lines in FIG. 4), airflow may exit the casing 22 through the foot
well outlet 40c. It should be understood that the first damper 80
may be moved to an intermediate position (i.e., between the first
and second positions) such that airflow may exit the casing 22
through both the defrost and foot well outlets 40b, 40c.
[0045] The second damper 82 is pivotally attached to the casing 22
and movable between a first position and a second position. When
the second damper 82 is in the first position (FIG. 4), airflow may
exit the casing 22 through one or both of the defrost and foot well
outlets 40b, 40c (depending on the position of the first damper 80,
as described above). When the second damper 82 is in the second
position (shown in phantom lines in FIG. 4), airflow may exit the
casing 22 through the vent outlet 40a. In this position, airflow is
prevented from exiting the casing 22 through either the defrost and
foot well outlets 40b, 40c. It should be understood that the second
damper 82 may be moved to an intermediate position (i.e., between
the first and second positions) such that airflow may exit through
the casing 22 through the vent outlet 40a and one or both of the
defrost and foot well outlets 40b, 40c (depending on the position
of the first damper 80, as described above).
[0046] The rear damper assembly 30 is disposed within the casing 22
proximate to the plurality of rear outlets 41. The rear damper
assembly 30 includes a first damper 84 and a second damper 86. The
first damper 84 is pivotally attached to the casing 22 and disposed
between the evaporator 42 and the heater core 44. The first damper
84 is also movable between a first position and a second position.
When the first damper 84 is in the first position (FIG. 4), airflow
through the rear cool flue 52 is directed through the heater core
44 and the rear heat flue 54 to the rear mix flue 55. When the
first damper 84 is in the second position (shown in phantom lines
in FIG. 4), airflow through the rear cool flue 52 is directed
directly to the rear mix flue 55. It should be understood that the
first damper 84 may be moved to an intermediate position (i.e.,
between the first and second positions) such that airflow through
the rear cool flue 52 may be directed to both the heater core 44
and directly to the rear mix flue 55. In this way, the temperature
of the airflow through the rear mix flue 55 may be a blend or mixed
of the airflow through the rear cool flue 52 and the rear heat flue
54.
[0047] The second damper 86 is pivotally attached to the casing 22
and movable between a first position and a second position. When
the second damper 86 is in the first position (shown in FIG. 4),
airflow through the rear mix flue 55 is directed to the foot well
outlet 41b. When the second damper 86 is in the second position
(shown in phantom lines in FIG. 4), airflow through the rear mix
flue 55 is directed to the vent outlet 41a. It should be understood
that the second damper 86 may be moved to an intermediate position
(i.e., between the first and second positions) such that the
airflow through the rear mix flue 55 may be directed to both the
foot well outlet 41b and the vent outlet 41a.
[0048] With reference to FIG. 5, a flowchart 500 showing an example
implementation of a control algorithm for reducing air leakage
through the rear air inlet 64 fluidly coupled to the rear airflow
passageway 36 of the HVAC unit 12 is shown. The control algorithm
begins at 504 when the vehicle 10 is turned on by a vehicle
operator (not shown) in the front region 16 of the vehicle cabin
18.
[0049] At 508, the control algorithm, using the controller 31,
determines if the vehicle operator desires airflow (heated and/or
cooled) only in the front region 16 of the vehicle cabin 18. This
determination maybe based on the user inputs received through the
user interface (not shown) of the vehicle 10. For example, the
vehicle 10 may have occupants (not shown) in the rear region 20 of
the vehicle cabin 18 who do not wish to have airflow to the rear
region 20. In this case, the operator positioned in the front
region 16 of the vehicle cabin 18 may desire to have airflow
thereto, and therefore, may operate the user interface of the
vehicle 10 so that airflow is allowed only in the front region of
the vehicle cabin 18. If the vehicle operator desires airflow only
in the front region 16 of the vehicle cabin 18, the control
algorithm proceeds to 512; otherwise, the control algorithm remains
at 508 until the operator desires airflow only to the front region
16 of the vehicle cabin 18.
[0050] At 512, the control algorithm, using the controller 31,
determines if the front blower motor of the front blower unit 26 is
in the ON mode. If the front blower motor of the front blower unit
26 is in the ON mode, the control algorithm proceeds to 520;
otherwise, the control algorithm proceeds to 516 where the front
blower is turned to the ON mode and then proceeds to 520.
[0051] At 520, the control algorithm, using the controller 31,
determines if the rear blower motor of the rear blower unit 24 is
in the OFF mode. If the rear blower motor of the rear blower unit
24 is in the OFF mode, the control algorithm proceeds to 528;
otherwise, the control algorithm proceeds to 524 where the rear
blower motor is turned to the OFF mode and then proceeds to
528.
[0052] In response to the rear blower motor turned to the OFF mode,
airflow through the front airflow passageway 36 may leak across the
evaporator 42 into the rear supply flue 50 and out the rear air
inlet 64 into the front region 16 of the vehicle cabin 18. This air
leakage may be discomforting to the operator in the front region 16
of the vehicle 10.
[0053] At 528, the control algorithm moves the first damper 84 of
the rear damper assembly 30 from the first position toward, or to,
the second position. In this way, the pressure drop of the rear
airflow passageway 38 is reduced, which, in turn, reduces the air
leakage to the rear supply flue 50 and out the rear air inlet 64
into the front region 16 of the vehicle cabin 18. Instead, the air
leakage is directed to the rear mix flue 55 and out the rear
outlets 41. In some configurations, the first damper 84 of the rear
damper assembly 30 may be moved to the intermediate position when
the vehicle cabin 18 is warm so that the air leakage may be
directed partially through the heater core 44. In this way, the
temperature of any air leakage out of the plurality of rear outlets
41 is substantially similar to the temperature of the vehicle cabin
18, and therefore, unnoticeable to the occupants in the rear region
20 of the vehicle cabin 18. After moving the first damper 84 of the
rear damper assembly 30 from the first position toward, or to, the
second position, the control algorithm then proceeds to 532.
[0054] At 532, the control algorithm moves the second damper 82 of
the rear damper assembly 30 to, or near, the intermediate position
to further distribute any air leakage from the rear mix flue 55
between the vent outlet 41b and the vent outlet 41b so that the air
leakage is unnoticeable by the occupants in the rear region 20. The
controller 31 then proceeds to 536 and ends.
* * * * *