U.S. patent application number 12/886515 was filed with the patent office on 2011-03-24 for hvac system.
This patent application is currently assigned to GLACIER BAY, INC.. Invention is credited to G. Kevin ALSTON, Machiko Taylor.
Application Number | 20110067420 12/886515 |
Document ID | / |
Family ID | 39367872 |
Filed Date | 2011-03-24 |
United States Patent
Application |
20110067420 |
Kind Code |
A1 |
ALSTON; G. Kevin ; et
al. |
March 24, 2011 |
HVAC SYSTEM
Abstract
An HVAC system for a vehicle. The HVAC system includes a battery
management controller, which can be used to run the components of
the HVAC system when the engine of the vehicle is not running.
Inventors: |
ALSTON; G. Kevin; (Union
City, CA) ; Taylor; Machiko; (Union City,
CA) |
Assignee: |
GLACIER BAY, INC.
|
Family ID: |
39367872 |
Appl. No.: |
12/886515 |
Filed: |
September 20, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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11560160 |
Nov 15, 2006 |
7797958 |
|
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12886515 |
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Current U.S.
Class: |
62/133 ; 62/180;
62/230; 62/238.7; 62/507; 62/515 |
Current CPC
Class: |
Y02E 60/10 20130101;
H01M 10/482 20130101; Y02T 10/88 20130101; H01M 50/20 20210101;
B60H 1/00428 20130101 |
Class at
Publication: |
62/133 ; 62/515;
62/230; 62/507; 62/180; 62/238.7 |
International
Class: |
B60H 1/32 20060101
B60H001/32; F25B 39/02 20060101 F25B039/02; F25B 49/02 20060101
F25B049/02; F25D 17/06 20060101 F25D017/06; F25B 27/00 20060101
F25B027/00 |
Claims
1. An HVAC system to be installed in a vehicle comprising: a
battery management controller comprising: at least one connection
for electrically coupling a first power source with a first
voltage; at least one connection for electrically coupling a second
power source with a second voltage; wherein the battery management
controller is configured to run a temperature control system and to
supply power to the temperature control system from a combination
of the first and second power sources with a combined voltage,
wherein the second power source is disconnected when the combined
voltage drops below a predetermined amount.
2. The HVAC system according to claim 1, wherein the second power
source is at least one battery connected to an engine starter of
the vehicle.
3. The HVAC system of claim 2, wherein the first power source is at
least one auxiliary battery.
4. The HVAC system of claim 3, wherein the battery management
controller is configured to gather historical data for any one of
the at least one auxiliary battery and the at least one battery
connected to the engine starter.
5. The HVAC system of claim 4, wherein the historical data is
maximum or average battery discharge.
6. The HVAC system of claim 3, further comprising a display for
showing current approximate battery charge of the at least one
auxiliary battery or the at least one battery connected to the
engine starter.
7. The HVAC system of claim 3, further comprising a
combination/separation device configured to connect the at least
one auxiliary battery to the engine starter to assist the at least
battery connected to the engine starter during start up of the
vehicle if the at least one battery connected to the engine starter
is weakened such that the vehicle has difficulty starting.
8. The HVAC system of claim 1 further comprising: a first power
source; a compressor; a motor operatively coupled to the
compressor; and a condenser in fluid communication with the
compressor.
9. The HVAC system of claim 8, wherein the first power source, the
compressor, the motor, and the condenser are configured to be
outside a cab of the vehicle as an exterior subsystem.
10. The HVAC system of claim 9, wherein the exterior subsystem is
configured to connect to a plurality of evaporators at one
time.
11. The HVAC system of claim 10, wherein the exterior subsystem is
configured to connect to the vehicle's existing evaporator.
12. The HVAC system of claim 8, wherein the compressor is a
stepless variable speed compressor that is controlled by a power
management controller.
13. The HVAC system of claim 8, further comprising an evaporator in
fluid communication with the condenser and a circulation blower
configured to flow air past the evaporator.
14. The HVAC system of claim 13, wherein the circulation blower is
a stepless variable speed control that is controlled by a power
management controller.
15. The HVAC system of claim 1, further comprising an electric
resistance heater.
16. The HVAC system of claim 1, further comprising a reverse cycle
heating system.
17. The HVAC system of claim 1, wherein the battery management
controller is configured to recharge the first and second power
sources by using a charging device.
18. The HVAC system of claim 17, wherein the battery management
controller is configured to connect the first and second power
sources to the charging device when the voltage of the first power
source is above a predetermined level and to only connect the
second power source to the charging device when the voltage of the
first power source is below a predetermined level.
19. The HVAC system of claim 1, wherein the predetermined amount is
an amount dynamically determined based on ambient operating
conditions
20. An HVAC system to be installed in a vehicle comprising: a
reverse cycle heating system; and a battery management system
configured to control the operation of the reverse cycle heating
system when the engine of the vehicle is turned off.
21. The system of claim 19, wherein the reverse cycle heating
system is run entirely by battery power.
22. An HVAC system to be installed in a vehicle comprising: a first
power source; a compressor; a motor operatively coupled to the
compressor; a condenser; and a power management controller
configured to run the motor when the engine of the vehicle is
turned off, wherein the first power source, the compressor, the
motor, and the condenser are configured to be outside a cab of the
vehicle as an exterior subsystem.
23. The HVAC system of claim 22, wherein the exterior subsystem is
configured to connect to a plurality of evaporators at one
time.
24. The system of claim 22, wherein the exterior subsystem is
configured to connect to the vehicle's existing evaporator.
Description
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS
[0001] This application is a Continuation of U.S. application Ser.
No. 11/560,160, filed Nov. 15, 2006, incorporated herein by
reference in its entirety.
BACKGROUND
[0002] The present invention relates to a heating, ventilation, and
air conditioning (HVAC) unit or system to be installed in a
vehicle.
[0003] Truck drivers that move goods across the country may be
required to pull over at various times along their journey so as to
rest so that they do not become too fatigued. Common places for
truck drivers to rest include rest stops, toll plazas, and the
like. However, these locations usually do not have any
accommodations for the drivers, and as a result they usually remain
inside the cab of the truck inside a sleeping compartment. To
provide the driver with maximum comfort, the sleeping compartment
should be temperature controlled so that the environment in the
truck is conducive for the driver to get the rest he or she
needs.
[0004] Currently, trucks tend to use engine-belt driven compressors
for the air conditioning system to circulate and pump refrigerant
throughout the vehicle to cool the driving compartments. In
addition, an engine-belt driven pump can circulate engine waste
heat throughout the driving compartments when heating is required.
Unfortunately, these systems have the drawback of not being able to
operate when the engine is turned off. As a result, the driver has
the choice of either keeping the engine running (which requires
additional fuel) so as to run the temperature control system or
turning the engine off and not using the air conditioning or
heating systems (which can make the driver uncomfortable).
[0005] In view of the above, there is a need to provide an HVAC
system which can provide temperature control when the engine is
turned off and can provide the necessary power to the heating and
cooling system. One option is to use the battery of the truck to
power the HVAC system. This option has the drawback that the HVAC
system may have to be turned off at a certain point so that the
battery does not drain to the point that the vehicle cannot be
started. Thus, there is a need to provide a battery management
system that will maximize the amount of time that the HVAC system
can run when the engine is turned off yet does not drain the
vehicle battery such that the vehicle cannot start.
[0006] Another drawback is that heaters used in the heating system
often run on diesel fuel. As previously mentioned, engine-belt
driven pumps can circulate engine waste heat throughout the driving
compartments for heating purposes but these pumps require fuel.
Alternatively, a dedicated burner can be used which pulls fuel from
the tank (when the engine is not running) and burns it to heat air
directly or through circulated water. Thus, there is a need to
provide a heating system in the HVAC system which is capable of
running while the engine is turned off such that no diesel fuel is
being expended.
[0007] Another drawback is that the replacement of an HVAC system
can result in a laborious and costly installation process. For
example, the replacement of an HVAC system might mean the
replacement of existing and fully functional equipment that is
already on the vehicle, such as replacing the evaporator,
circulation fans, or ducting. Thus, there is a need to provide an
HVAC system that can be easily installed and does not necessarily
involve the replacement of all the existing components of a
vehicle's HVAC system.
SUMMARY
[0008] According to one embodiment of the present invention, an
HVAC system to be installed in a vehicle is disclosed, which
comprises a battery management controller. The battery management
controller can comprise at least one connection for electrically
coupling a first power source with a first voltage and at least one
connection for electrically coupling a second power source with a
second voltage. The battery management controller can be configured
to run a temperature control system and to supply power to the
temperature control system from a combination of the first and
second power sources with a combined voltage, wherein the second
power source is disconnected when the combined voltage drops below
a predetermined amount.
[0009] According to another embodiment of the present invention, an
HVAC system to be installed in a vehicle is disclosed, which
comprises a reverse cycle heating system and a battery management
system configured to run the reversed heating system when the
engine of the vehicle is turned off.
[0010] According to a further embodiment of the present invention,
an HVAC to be installed in a vehicle is disclosed, which comprises
a first power source; a compressor; a motor operatively coupled to
the compressor; a condenser; and a battery management system
configured to run the motor when the engine of the vehicle is
turned off. The first power source, the compressor, the motor, and
the condenser can be configured to be outside a cab of the vehicle
as an exterior subsystem.
[0011] It is to be understood that both the foregoing general
description and the following detailed description are exemplary
and explanatory only, and are not restrictive of the invention as
claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The features, aspects and advantages of the present
invention will become apparent from the following description,
appended claims, and the accompanying exemplary embodiments shown
in the drawings, which are briefly described below.
[0013] FIG. 1 is a schematic diagram of an HVAC system to be
installed in a vehicle according to an embodiment of the present
invention.
[0014] FIG. 2 is a schematic diagram of an HVAC system according to
another embodiment of the present invention.
[0015] FIG. 3 is a schematic diagram of an alternative
configuration of the HVAC system of FIG. 2 according to an
embodiment of the present invention.
[0016] FIG. 4 is a schematic diagram of an HVAC system according to
another embodiment of the present invention.
[0017] FIGS. 5(a) and 5(b) are schematic diagrams of the battery
management controller and the power management controller,
respectively, according to an embodiment of the present
invention.
[0018] FIGS. 6(a) and 6(b) are flow charts showing the operation of
the battery management controller during the discharging and
recharging of the power sources, respectively, according to an
embodiment of the present invention.
[0019] FIG. 7 is a flow chart showing the operation of the power
management controller according to an embodiment of the present
invention.
[0020] FIG. 8 is a schematic diagram of an HVAC system to be
installed in a vehicle according to an embodiment of the present
invention.
DETAILED DESCRIPTION
[0021] Hereinafter, various embodiments of the present invention
will be described in detail with reference to the drawings.
[0022] FIG. 1 is a schematic diagram of an HVAC system to be
installed in a vehicle according to an embodiment of the present
invention. The HVAC system 10 may comprise a motor 12, a compressor
14, circulation blowers 210 and 212, a power management controller
50, and a battery management controller 60. The motor can be
operatively coupled to the compressor 14. The compressor 14 is a
stepless continuously variable speed compressor, which is driven by
the motor 12. The compressor 14 circulates refrigerant through the
condenser 16 to an optional refrigerant receiver and dryer 18. From
the refrigerant receiver and dryer 18, the refrigerant then passes
to either a first cooling path 21 that cools the driving
compartment 23 or a second cooling path 25 that cools the sleeping
compartment 27 of the vehicle. As to the first cooling path 21, the
refrigerant passes through a refrigerant metering device 20 and an
evaporator 22. The refrigerant metering device 20 may or may not be
an expansion device, such as a thermostatic expansion valve, a
pressure control expansion valve, a capillary tube, or the like,
used in the conventional way. In one arrangement, the refrigerant
metering device 20 is a metering device feeding refrigerant into
the flooded evaporator 22 with no expansion taking place at or near
the valve 20, and thus merely meters in liquid refrigerant at a
rate sufficient to maintain the correct liquid level in the
evaporator. Air is blown over the evaporator 22 by the circulation
blower 210. After the air is cooled by the evaporator 22, the air
proceeds through an air duct 272 towards the driving compartment 23
of the vehicle.
[0023] A second cooling path 25 runs parallel to the first cooling
path 21 in which the refrigerant is provided through a refrigerant
metering device 24 and an evaporator 26. Air is blown over the
evaporator 26 by a circulation blower 212. After the air is cooled
by the evaporator 26, the air proceeds through an air duct 276
towards the sleeping compartment 27 of the vehicle. The evaporator
26 of the second cooling path 25 can be smaller than the evaporator
22 of the first cooling path 21 because the sleeping compartment 27
is typically smaller than the driving compartment 23.
[0024] The two coolant loops may be selectable through the use of
valves 28 and 29. The inclusion of such valves permits the driving
compartment 23, the sleeping compartment 27, or both compartments
to be air conditioned at a particular time. The valves 28 and 29
can be controlled through the power management controller 50 (to be
discussed below). Once the refrigerant passes through the
evaporator 22 and/or 26, the refrigerant then passes through an
optional refrigerant accumulator 30 before being returned to the
compressor 14 to restart the process.
[0025] The motor 12 can be any suitable motor. For example, the
motor 12 can be a brushless DC motor that is commutated by a square
or trapezoidal wave form. In another example, the motor 12 can be a
synchronous permanent magnet motor that is commutated with a sine
wave. When the motor is driven by a sine wave, additional benefits
can be obtained, such as better drive efficiency, better cooling
and quieter operation.
[0026] By using a variable speed compressor 14 driven by a
brushless DC or a synchronous permanent magnet motor 12, the
vehicle's HVAC system may be operated when the engine is turned on
or when the engine is turned off. The variable speed compressor 14
also can permit the HVAC system 10 to operate at a lower capacity
during the engine off operation to conserve the amount of stored
energy available for usage by the system 10. The control for this
operation is provided by a power management controller 50 that
monitors various system parameters while the battery management
controller 60 monitors the availability and status of the power
sources on the vehicle. The available power sources can include a
first power source 40, a second power source 42, and/or the
vehicle's main electrical power generation system 44.
[0027] In a similar manner, the circulation blowers 210 and 212 can
also have stepless continuously variable speeds such that the
circulation blowers can operate at a lower capacity during the
engine off operation to conserve the amount of stored energy
available for usage by the HVAC system 10. The control for this
operation is also provided by the power management controller
50.
[0028] The battery management controller 60 is configured such that
the vehicle's HVAC system 10 is capable of being powered by the
vehicle's main electrical power generation system 44, which is
available while the vehicle's engine is operating. When the
vehicle's engine is off, the HVAC system 10 can be powered with a
first power source 40 and/or a second power source 42 depending on
the power levels of the power sources (as will be described later).
In one embodiment, the first power source 40 can be one or more
auxiliary deep-cycle batteries and the second power source 42 can
be the vehicle's one or more starter batteries. In another
embodiment, one of the first and second power sources may be an
external source of AC power connected to the system through an
external connection.
[0029] In the HVAC system 10, the motor driven compressor 14 can
have the ability to modulate its output from full capacity to low
capacity. This ability to modulate allows the use of a single HVAC
system that can be used for both high output for the time periods
that the engine is operating, and low output during the time
periods when the engine is turned off so as to continue to cool or
heat the driving and/or sleeping compartments. The coordination of
this modulation is provided by the power management controller 50,
which reduces the speed of the compressor when the engine is turned
off. This modulation extends the duration of the heating and
cooling operations because the charge of the available power
sources is expended more slowly. That is, with a reduced speed of
the compressor, the electric power demand is reduced as well.
[0030] Another aspect of FIG. 1 is a heating mode of operation in
which there is an air heater in each air duct that leads to the
vehicle compartments. For example, the air heater 270 is disposed
in the air duct 272 which leads to the driving compartment 23. The
air heater 274 is disposed in the air duct 276 which leads to the
sleeping compartment 27. The air heaters 270 and 274 may be any
heater known in the art, such as an electric resistance-type
heater. The advantage of using an electric resistance-type heater
is that such a heater allows the heating function to be completed
without relying on the engine or additional fuel by merely relying
on the circulation blowers and the heaters, which are powered by
the first and/or second power sources or the vehicle electrical
power generation system. In a preferred embodiment, instead of the
air ducts 272 and 276, the air heaters 270 and 274 can be placed
within the same enclosures as the circulation blowers 210 and 212
but still in the path of the gas stream which enters the vehicle
and/or sleeping compartments. If the air heaters are in the same
enclosures as the circulation blowers, there can be a reduction in
the complexity of the installation.
[0031] To operate in the heating mode, the power management
controller 50 does not operate the compressor 14 but merely
operates the circulation blower 210 and the air heater 270 to
provide the necessary heating to the driving compartment and/or the
circulation blower 212 and the air heater 274 to provide the
necessary heating to the sleeping compartment. This configuration
provides additional power consumption savings and allows for a
longer operating duration in the heating mode. In the cooling mode
of operation, the air heaters 270 and 274 are simply not activated.
If temperature control is desired, the power management controller
50 can preferably provide pulse width modulation control (PWM) of
power to the air heaters 270 and 274. Alternatively, temperature
control can be performed by a control door known in the art (not
shown) placed in each duct (if provided) to control the flow of air
(which may or may not be cooled by the evaporators 22 and/or 26)
passing over the air heaters 270 and/or 274 to regulate the
temperature of the air flowing into their respective vehicle
compartments.
[0032] The embodiment of FIG. 1 can include alternative
configurations. For example, the first or second cooling path can
be eliminated such that there is only one expansion device, one
evaporator, one blower, and no accumulator 30. With this
configuration only one vehicle compartment can be temperature
controlled. Alternatively, ducting can be used to channel the
temperature controlled air into separate channels in which a first
channel goes to the driving compartment and a second channel goes
to the sleeping compartment. In this embodiment, a control door or
the like can be used to channel the temperature controlled air to
one compartment to the exclusion of the other.
[0033] FIG. 2 is a schematic diagram of another embodiment of the
HVAC system 10 according to another embodiment of the present
invention. The HVAC system 10 of this embodiment includes a primary
coolant loop 170 that includes a first refrigerant and a secondary
coolant loop 172 that includes a second refrigerant. The first
refrigerant in the primary coolant loop 170 is driven by the
compressor 14 which passes through the condenser 16, the receiver
and dryer 18, the refrigerant metering device 20, the first
refrigerant-to-second refrigerant heat exchanger 174, and back to
the compressor 14.
[0034] In contrast, the second refrigerant in the secondary coolant
loop 172 is driven by a low pressure liquid pump 176. The fluid
passes through a second refrigerant-to-air heat exchanger 178, a
heater 180, and the first refrigerant-to-second refrigerant heat
exchanger 174. The first refrigerant-to-second refrigerant heat
exchanger 174 serves as the heat exchange medium between the
primary coolant loop 170 and the secondary coolant loop 172. The
second refrigerant-to-air heat exchanger 178 cools the air supplied
by the circulation blower 210, which then flows to the vehicle
compartment with or without ducting. To provide heating of the
vehicle compartment, the power management controller 50 need only
operate the low pressure liquid pump 176 and the heater 180 in the
secondary coolant loop 172 and the circulation blower 210. That is,
no power is delivered to the compressor 14, and as a result the
amount of power consumption is further reduced, which extends the
time duration that heating can take place.
[0035] FIG. 3 shows an alternative configuration of FIG. 2 in which
there are two second refrigerant-to-air heat exchangers 178 and 182
in the secondary coolant loop 172. One second refrigerant-to-air
heat exchanger 178 can be used to provide cooling/heating to the
driving compartment 23 while the other heat exchanger 180 can be
used to provide cooling/heating to the sleeping compartment 27 with
or without ducting. The passage of the liquid through either or
both of the heat exchangers 178 and 182 can be selected by the
power management controller 50, which, in turn, controls the valve
184 that leads to the heat exchanger 180 and the valve 186 that
leads to the heat exchanger 178. Thus, the control of the valves
184 and 186 permits the driving compartment 23, the sleeping
compartment 25, or both compartments to be air conditioned or
heated at a particular time.
[0036] FIG. 4 shows another embodiment of the present invention in
which the HVAC system uses a reverse cycle heating system. The
reverse cycle heating system also allows the heating function to be
completed without relying on the engine or additional fuel by
merely relying on the compressor and the circulation blowers, which
are powered by the first and/or second power sources or the vehicle
electrical power generation system. As with the embodiment shown in
FIG. 1, the HVAC system 10 of FIG. 4 may comprise a motor 12, a
compressor 14, circulation blowers 210 and 212, a power management
system 50, and a battery management system 60. The motor can be a
brushless DC or a synchronous permanent magnet motor, which is
operatively coupled to the compressor 14. The compressor 14 is a
continuously variable speed compressor, which is driven by the
motor 12. Connected to the compressor is a reversing valve 502,
which allows the compressor to pump refrigerant in a cooling
direction indicated by single arrows 520 or a heating direction
indicated by double arrows 522.
[0037] As to the cooling direction, the compressor 14 circulates
refrigerant through a heat exchanger 504 (which functions as a
condenser in the cooling mode as the hot compressed gas from the
compressor condenses to a liquid as heat is given off) to a first
flow path 510 that thermally treats air going to the driving
compartment 23 and/or a second flow path 512 that thermally treats
air going to the sleeping compartment 27 of the vehicle. As to the
first flow path 510, the refrigerant passes through a refrigerant
metering device 20 and a heat exchanger 506 (which functions as an
evaporator in the cooling mode as the liquid refrigerant boils and
forms a gas as heat is absorbed by the refrigerant liquid). Air is
blown over the heat exchanger 506 by the circulation blower 210.
After the air is cooled by the heat exchanger 506, the air proceeds
towards the driving compartment 23 of the vehicle.
[0038] A second flow path 512 runs parallel to the first flow path
510 in which the refrigerant is provided through a refrigerant
metering device 24 and a heat exchanger 508 (which functions as an
evaporator during the cooling mode as the liquid refrigerant boils
and forms a gas as heat is absorbed by the refrigerant liquid). Air
is blown over the heat exchanger 508 by a circulation blower 212.
After the air is cooled by the heat exchanger 508, the air proceeds
towards the sleeping compartment 27 of the vehicle. The heat
exchanger 508 of the second flow path 512 can be smaller than the
heat exchanger 506 of the first flow path 510 because the sleeping
compartment 27 is typically smaller than the driving compartment
23.
[0039] The two coolant loops may be selectable through the use of
valves 28, 29, 514, and 516. The inclusion of such valves permits
the driving compartment 23, the sleeping compartment 25, or both
compartments to be air conditioned at a particular time. The valves
28 and 514 are opened and the valves 29 and 516 are closed when
only the driving compartment is being temperature controlled. By a
similar token the valves 29 and 516 are opened and the valves 28
and 514 are closed when only the sleeping compartment is being
temperature controlled. The valves 28, 29, 514, and 516 can be
controlled through the power management controller 50. Once the
refrigerant passes through the heat exchanger 506 and/or 508, the
refrigerant then returns to the reversing valve 502 and the
compressor 14 to restart the process.
[0040] As to the heating direction, the reversing valve 502 is
switched such that the refrigerant pumped by the compressor flows
in the reverse direction as indicated by double arrows 522. Thus,
the compressor causes the refrigerant to flow through the first
flow path 510 and/or the second flow path 512 depending if the
valves 28 and 514 and the valves 29 and 516 are opened or closed.
If the valves 28 and 514 are opened, the refrigerant flows through
the heat exchanger 506 (which functions as a condenser in the
heating mode as the hot gas is condensed to a liquid as it gives up
heat). Air is blown over the heat exchanger 506 by the circulation
blower 210. After the air is heated by the heat exchanger 506, the
air proceeds towards the driving compartment 23 of the vehicle.
Meanwhile, the refrigerant continues from the heat exchanger 506
through the refrigerant metering device 20 to the heat exchanger
504 (which functions as an evaporator in the heating mode). After
flowing through the heat exchanger 504, the refrigerant returns to
the reversing valve 502 and the compressor 14.
[0041] If the valves 29 and 516 are opened, the refrigerant flows
through the heat exchanger 508 (which functions as a condenser in
the heating mode). Air is blown over the heat exchanger 508 by a
circulation blower 212. After the air is heated by the heat
exchanger 508, the air proceeds towards the sleeping compartment 27
of the vehicle. Meanwhile, the refrigerant continues from the heat
exchanger 506 through the refrigerant metering device 24 to the
heat exchanger 504 (which functions as an evaporator in the heating
mode). After flowing through the heat exchanger 504, the
refrigerant returns to the reversing valve 502 and the compressor
14 to restart the process.
[0042] Similar to the embodiment shown in FIG. 1, the embodiment of
FIG. 4 can include a variable speed compressor 14 driven by a
brushless DC or a synchronous permanent magnet motor 12; the
control for the heating and cooling operations being provided by
the power management controller 50; the available power sources can
include a first power source 40, a second power source 42, and/or
the vehicle's main electrical power generation system 44; the
circulation blowers 210 and 212 can also have continuously variable
speed which can be controlled by the power management controller
50; and the battery management controller 50 can monitor and
control the available power sources when the engine is turned
off.
[0043] Also as with the embodiment of FIG. 1, FIG. 4 can include
alternative configurations. For example, the first or the second
cooling path can be eliminated such that there is only one
refrigerant metering device, one heat exchanger in which air passes
over, and one blower. With this configuration only one vehicle
compartment can be temperature controlled. Alternatively, ducting
can be used in which the duct channeling the temperature controlled
air can be spit into multiple channels such that a first channel
goes to the driving compartment and a second channel goes to the
sleeping compartment. In this embodiment, a control door or the
like can be used to channel the temperature controlled air to one
compartment to the exclusion of the other.
[0044] The power requirements and operation of the HVAC system 10
are handled by the battery management controller 60 and the power
management controller 50, respectively. The two controllers 50 and
60 can be software control loops with associated hardware or
circuitry, and they may be physically housed in separate devices or
the same device.
[0045] The battery management controller 60 will now be discussed
with reference to FIG. 5(a). The battery management controller 60
can fulfill a variety of different purposes including: (1)
maximizing the electrical power available for use by the HVAC
system; (2) ensuring that sufficient electrical reserve power is
available to start the engine; (3) tracking historical use (charge
and discharge) of all connected batteries; (4) determining the
current state of charge of all connected batteries; (5) determining
the current end-of life status of all connected batteries
irrespective of their respective charge level; (6) ensuring that
the charge and discharge cycles of all connected batteries are
consistent with the user's preferred compromise between battery
longevity and available stored energy; and (7) prevent overloading
of the battery charging system.
[0046] The battery management controller 60 carries out its
function by being connected to a plurality of power sources 40 and
42, a combination/separation device 61, and a charging device 61.
In one exemplary embodiment, a truck can have seven batteries in
which four batteries are connected in parallel to provide a high
capacity first battery bank as the first power source 40 and the
three remaining batteries are connected in parallel to provide a
second, somewhat smaller battery bank as the second power source
42.
[0047] The first power source 40 and/or the second power source 42
are connected to a separation device 61, temperature and voltage
sensors 63, and an engine starter 64. The first and second power
sources (e.g., the first and second battery banks) are connected to
the combination/separation device 61 so as to allow the first and
second power sources to be electrically combined or separated.
[0048] The combination/separation device 61 can be electrically
connected to supply power to the individual components of the HVAC
system 10 and can optionally be connected to other electrical power
accessories, such as microwave ovens, televisions, stereos,
refrigerators, etc. The combination/separation device 61 is
configured to electrically split and combine multiple power sources
so as to maximize the availability of power to the components of
the HVAC system 10 and the engine starter 64. Furthermore, the
combination/separation device 61 can electrically split and combine
multiple batteries to prevent overloading of a charging device 62,
such as an alternator, by selectively combining the discharged
power sources into a partially charged pack.
[0049] The temperature and voltage sensors 63 can monitor the
voltage and temperatures of the first and second power sources 40
and 42. These sensors can be used to monitor the state of charge of
the power sources so as to prevent the power sources from being
overly discharged.
[0050] The engine starter is connected to one of the power sources
so as to provide enough power to start the engine of the vehicle.
The engine starter 64 can be electrically connected to the first
power source or the second power sources but not to both. Also, the
engine starter 64 may have an optional connection 65 that leads
directly to the combination/separation device 61.
[0051] The charging device 62 can be connected to the
combination/separation device 61 so that the electrical power
output from the charging device 62 can be selectively routed to any
individual or combination of connected power sources. The charging
device can comprise one or more of the following: the engine
alternator, an accessory generator, a show power connection, and
other charging devices.
[0052] The battery management controller 60 can include a control
logic circuit 66 and a memory 67, and can be connected to the
voltage and temperature sensors 63, a user interface 51 (which can
comprise a display 310 and one or more input devices 312), the
combination/separation device 61, and the power management
controller 50. Thus, the battery management controller 60 can
receive measurements from the voltage and temperature sensors 63
and user preferences from the user interface 51. Additionally the
battery management controller 60 can receive and transmit
information in a bi-direction manner to and from the power
management controller 50. The battery management controller 60 is
used to regulate the degree of discharge among the power sources so
as to conform to the user preferred compromise between the daily
battery performance and the ultimate life of the power sources. In
addition, the memory 67 of the battery management controller can be
used to log historical data obtained during previous charge and
discharge cycles, such as voltage and temperature levels, and use
the historical data to modify the permitted depth of discharge to
ensure the completeness of future charge cycles.
[0053] In a more conventional HVAC system, the measurement of the
battery voltage under load is used to determine the
state-of-charge. While this method is low in cost and easy to
implement, it is also highly inaccurate. The voltage can be used to
accurately determine the state-of-charge but only when such
measurements are taken in conjunction with temperature and only
after the battery has been "at rest" (i.e., unloaded) for a period
or time (typically over one hour). In contrast, the battery
management controller 60 of FIG. 5(a) can use multiple sources of
historical and real-time data to more accurately determine the
amount of stored energy available for use. Additionally, the
battery management controller 60 allows a highly accurate "resting
voltage" measurement of the state of charge to be made of the power
reserve even when portions of the battery power supply are still in
use. Below is a discussion of the processes that occur during the
discharging of the power sources when in the engine is turned off,
the starting up of the engine, and the charging of the power
sources when the engine is turned on. In the discussion below, the
first and second power sources are battery banks but is should be
recognized that any type of power source can be used. For example,
one of the first and second power sources may be an external AC
connection.
[0054] The process that the battery management control circuit
undergoes during discharge is provided in FIG. 6(a). The
discharging of the first and/or second battery banks occurs when
the engine is turned off as shown in step 402, and a command is
issued from the power management controller 50 ("PMC") to the
battery management controller 60 ("BMC") to supply power to the
components of the HVAC system 10 as shown in step 404. In step 406,
upon receiving the command from the power management controller 50,
the battery management controller 60 through its control circuit 66
would determine the state of charge of the combination of the first
and second battery banks by comparing the current voltage and
temperature of the combined banks from data received by the voltage
and temperature sensors 63 with the historical data stored in the
memory 67 of the controller 60. If there is sufficient charge with
both power sources, the process proceeds to step 408. If there is
not sufficient charge, the process proceeds to step 430.
[0055] At step 408, upon determining that sufficient stored energy
was available for use, the first and second battery banks 40 and 42
would be electrically combined through the combination/separation
device 61 so as to supply power to the components of the HVAC
system 10. The power draw (current) from the HVAC system 10 is
monitored and the rate of decline in the combined battery banks 40
and 42 is noted. The power draw and rate of decline is compared to
historical data to determine the approximate state of sulfation of
the battery plates and from this comparison, the approximate
condition of the batteries is deduced. Under a given load, the
voltage of batteries in poor condition will decline faster than
batteries in good condition. Consequently, it can be predicted that
batteries in poor condition will have less total stored energy even
though the actual voltage at any given time may be the same. In one
example, data can be collected related to the maximum battery
discharge and/or the average battery discharge during an operation
cycle of the power sources when the power sources are batteries.
This data can be compiled over time such that a history of the
maximum and/or average battery discharge is stored in the memory 67
in the battery management controller 60.
[0056] As the voltage of the combined batteries falls, the battery
management controller logic circuit 66 will use the temperature,
the load, the rate of voltage change, the estimated battery
condition, the stored historical data and the user preference
inputted from the user interface 51 to determine the preferred
voltage point at which to separate the first and second battery
bank 40 and 44 using the combination/separation device 61. The user
interface can comprise a display 310 and one or more input devices
312, such as a keyboard, a control panel, or the like, so that the
vehicle occupant can input user preferences for the operation of
the HVAC system 10. For example, the user preferences can include
the operating mode of the HVAC system such as off, heating, and
cooling modes of operation.
[0057] The user preferences which are inputted using the user
interface 51 are also those factors that influence the extent to
which the battery banks 40 and 42 will be allowed to be discharged.
One example is the battery replacement life. Battery replacement
life is related to the depth of the discharge of the power source
as well as the rate of discharge, i.e., a function of the minimum
battery voltage adjusted by the load. For example, a lightly loaded
battery which is consistently discharged to 11.8 V may only last
through 100 charge/recharge cycles while a heavily loaded battery
that was consistently discharged to 11.8 V might last 200
charge/recharge cycles. If a user preference is set for a long
battery life, the batteries will be less deeply discharged and will
last longer. However, because less stored energy will be available
for use, more batteries will need to be carried to supply a given
amount of cooling or heating than would be the case if a shorter
battery life (and more deeply discharged batteries) were
selected.
[0058] In addition, the display 310 of the user interface 51 can
provide a user, such as a vehicle occupant, information related to
the status of the HVAC system 10. The display can include one or
more of an alphanumerical display, a graph, or the like. For
example, the display can include the vehicle's interior ambient
temperature, the exterior ambient temperature, the circulation
blower speeds, the usage of the power source or sources supplied to
the HVAC system 10, and warning messages, etc. In one example, if
the first power source and the second power source are batteries,
the display can show the current approximate battery charges for
each power source to the vehicle occupant.
[0059] As the HVAC operation continues, the combined battery bank
voltage can be continually monitored. The preferred voltage point
is determined based on the temperature, the load, the rate of
voltage change, the estimated battery condition, the stored
historical data and user preferences such that the preferred
voltage point becomes a predetermined amount of voltage that is
dynamically determined based on ambient operating conditions in
which the first and second power sources separate if the combined
voltage drops below the predetermined amount. If the voltage does
not drop below the preferred voltage point, the monitoring of the
power draw and rate of decline is continued. If the combined bank
voltage eventually falls to the preferred voltage point, the
battery management controller logic circuit 66 commands the
combination/separation device 61 to electrically separate the first
and second battery banks 40 and 42 at step 410. Once separated, the
HVAC power is supplied solely by the first battery bank 40 while
the second bank (i.e., the battery bank connected to the engine
starter 64) is isolated and the voltage of the second battery bank
partially recovers to an unloaded resting state. In time it will be
possible to use this "resting" voltage to accurately determine the
state of charge of the isolated bank. Then, a determination will
then be made by the control logic circuit 66 about whether
additional power can be safely drawn from the isolated bank.
[0060] With continued operation of the HVAC system 10, the voltage
of first battery bank 40 continues to decline. The battery
management controller logic circuit re-analyzes the battery bank 40
by comparing real time data on the power draw, the temperature and
the rate of voltage decline with the stored historical data and the
user input preferences to determine the amount of stored energy
available. A determination is made of the minimum system disconnect
voltage, i.e., the battery cut-out voltage. From this
determination, a calculation is made of the estimated time to
battery depletion for the first battery and this estimated time
information is communicated to the power management controller 50.
Because the estimated time information is based on both static data
(such as historical and user input) and real-time data (such as
current voltage levels and temperatures), a change in the
performance, the system load or the ambient conditions during the
operation of the HVAC system 10 can change the estimated time
information which may increase or decrease the calculation of the
available system run time.
[0061] As the HVAC system 10 continues to run, the voltage level of
the first battery is monitored in step 410. As long as there is
sufficient voltage, the battery management controller will continue
to have the first battery bank power the HVAC components and
monitor the first battery bank's voltage level. However, the power
can eventually be depleted from the first battery bank 40 to the
point where the voltage falls to the level calculated by the
control logic circuit to be the minimum allowed, i.e., the battery
cut-out voltage, and disconnect the first battery bank 40 as shown
in step 412. If continued operation of the HVAC system 10 is
desired, the battery management controller logic circuit 66 will
use the resting voltage measurement of the second battery bank 42
(which has been isolated) to determine how much, if any, additional
power can safely be drawn from that bank at step 414. If power is
available from the second battery bank (the "YES" path), the
control logic circuit 66 will set a second lower voltage level at
step 416 and command the combination/separation device 61 to
re-route power from the second battery bank 42. As the HVAC system
10 continues to run, the voltage level of the second battery is
monitored. If the voltage level remains above the second voltage,
the process remains at step 416. Power will then continue to be
supplied by the second bank 42 until such time as the voltage of
the second bank 42 falls below the second lower voltage. At that
time, the battery management controller logic circuit will command
the combination/separation device 61 to cut off all power to the
HVAC system 10 at step 420. However, if no additional power is
available from the second bank 42, the battery management
controller logic circuit will just command the
combination/separation device 61 to cut off all power to the HVAC
system 10 at step 420.
[0062] In contrast, if there is insufficient charge in both battery
banks at step 406, the battery management controller determines if
there is sufficient charge in one of the battery banks at step 430.
If there is not sufficient charge in either battery bank (the "NO"
path), the battery management controller logic circuit will command
the combination/separation device 61 to cut off all power to the
HVAC system 10 at step 430. If there is sufficient charge in one of
the battery banks (the "YES" path), the particular battery bank
with sufficient charge would supply power to the components of the
HVAC system 10 at step 432. The battery management controller logic
circuit analyzes the selected battery bank by comparing real time
data on the power draw, the temperature and the rate of voltage
decline with the stored historical data and the user input
preferences to determine the amount of stored energy available. A
determination is made of the minimum system disconnect voltage,
i.e., the battery cut-out voltage. From this determination, a
calculation is made of the estimated time to battery depletion for
the selected battery and this estimated time information is
communicated to the power management controller 50. Because the
estimated time information is based on both static data (such as
historical and user input) and real-time data (such as current
voltage levels and temperatures), a change in the performance, the
system load or the ambient conditions during operation of the HVAC
system 10 can change the estimated time information which may
increase or decrease the calculation of the available system run
time.
[0063] As the HVAC system 10 continues to run, the voltage level of
the selected battery bank is monitored. If there is sufficient
voltage, the battery management controller will continue the
monitoring process. However, the power can eventually be depleted
from the selected battery bank to the point where the voltage falls
to the level calculated by the control logic circuit to be the
minimum allowed, i.e., the battery cut-out voltage. Once the
voltage level falls below this minimum, the battery management
controller logic circuit will command the combination/separation
device 61 to disconnect the selected battery bank at step 434; thus
cutting off all power to the HVAC system 10 at step 420.
[0064] At the end of the discharge cycle, the battery management
controller 60 has regulated the battery banks 40 and 42 so that the
first battery bank 40 is more deeply discharged than the second
bank 42. Additional power has been reserved in the second battery
bank 42, which is the bank to which the engine starter 64 is
connected, thus ensuring that sufficient energy is available to
start the engine. Because the charge level of the two banks is
different, the voltage level is also different. Therefore, the
battery management controller logic circuit 66 commands the
combination/separation device 61 to keep the two battery banks
electrically separated and can monitor the voltage of each bank
individually.
[0065] At the start up of the engine, a heavy electrical load is
applied to the second bank 42 causing the voltage of the second
bank 42 to drop. The amount of drop depends on the condition, the
state of charge, and the temperature of the second bank 42 as well
as the engine itself. Thus, there is a chance that under certain
adverse conditions, the voltage drop will be so severe as to
prevent the engine from starting unless additional electrical power
is made available.
[0066] By monitoring the voltage of the first bank 40 separately
from the second bank 42, and by monitoring the rate of charge of
the voltage in the second bank 42 at the time the electrical load
is applied at the engine start up cycle, the battery management
controller logic circuit 66 can determine if additional electrical
power is available in the first battery bank 40 to provide a
starting boost. If the control algorithm in the battery management
controller logic circuit 66 determines that such power is
available, the logic circuit 66 will command the
combination/separation device 61 to electrically combine the first
battery bank 40 with the second battery bank 42 during the engine
start up cycle. In this case, the engine starter 64 is connected to
the combination of the first and second battery banks 40 and 42
through the combination/separation device 61 via the optional
connection 65; thus allowing the engine to be started. After the
engine is started, the battery management controller logic circuit
switches to its charge mode algorithm as will be described
next.
[0067] FIG. 6(b) is a flow chart showing the process for charging
the batteries after the engine has been turned on. After the engine
has started up at step 450, one or more power sources can be used
to recharge the first and second battery banks 40 and 42. When the
charging device 62 (such as the alternator) is activated at step
452, the battery management controller logic circuit 66 reviews the
historical data from the last discharge cycle to estimate the
amount of load that the recharging operation will be put on the
charging device 62 at step 454. Previously entered user input from
the user interface 51 will be used to determine if this estimated
load is "high" or "low." A deeply discharged battery bank and/or
large battery banks that contain a great deal of storage capacity
are more likely to cause a "high" load than smaller or more lightly
discharged batteries. Therefore, if the estimated load is
determined to be "high," the battery management controller logic
circuit commands the combination/separation device at step 456 to
route the electrical power from the charging device 62 to only to
the second battery bank 42 (i.e., the bank connected to the engine
starter 64). Once the second bank has reach a state of charge
sufficient to significantly reduce the load on the charging device
62, the control logic circuit commands the combination/separation
device 61 at step 458 to electrically combine the first and second
battery banks 40 and 42 so that all batteries get recharged. If, at
the beginning of the recharge cycle, the battery management
controller logic circuit determines that the load will be "low"
then all batteries from both the first and second battery banks 40
and 41 are combined via the combination/separation device 61 and
charged together at step 460. From either step 458 or step 460, the
charging of both battery banks is continued until both are fully
charged or the engine is turned off at step 462.
[0068] According to one embodiment of the present invention, so as
to ensure that the batteries are fully recharged between cycles to
prevent premature sulfation and destruction of the batteries, the
battery management controller can also monitor and store the time
and power levels of the batteries during the discharge and recharge
cycles. This historical data can verify that, in a typical
discharge and re-charge cycle, sufficient time and power is
available to fully recharge the batteries. If there is not
sufficient time and power to fully recharge, the control logic
circuit 66 can respond by raising the minimum battery cut-off
voltages thereby reducing the total amount of power which can be
drawn from the battery banks. In other words, the battery
management controller 60 can be configured to be self-learning
which allows the controller to maximize the battery replacement
life by monitoring the first and/or second power sources such that
they are not excessively discharged (i.e., drained) and such that
they are not discharged to a level that does not allow the power
source to be fully recharged during the typical engine run time.
For example, consider that a power source might be a battery in
which the battery can be safely discharged to a level X. Thus, the
level X can be the predetermined amount value during the
determination of whether the power source should be connected to
the HVAC system. However, if the run cycle of the engine was too
short to allow the battery to fully recharge during the engine run
after the battery had been partially discharged, the battery would
still be prematurely destroyed because failure to fully recharge a
battery is just as harmful as discharging it too deeply (or
draining the charge too much). To prevent the premature destruction
of a battery due to it not being fully recharged, the battery
management controller 60 can monitor the battery charge in the
power source to determine if the battery was fully recharged. If
the battery was not, then the controller 50 can be configured to
"learn" during the next operation where the power source is
connected and the engine is turned off that the battery should be
less deeply discharged, i.e., the battery should be discharged to a
level Y, which is greater than the level X. Then, the level Y can
be the predetermined amount value during the determination of
whether the power source should be connected to the HVAC
system.
[0069] Next, the power management controller 50 will be described.
The power management controller 50 controls the components of the
HVAC system 10, and works in conjunction with the battery
management controller 60. The purpose of the power management
controller 50 is to: (1) communicate to the user via the user
interface; (2) monitor safety functions and initiate appropriate
responses; (3) maximize the operational efficiency of the HVAC
system by optimizing the speed of the condenser and evaporator fans
and the speed of the compressor motor according to ambient
conditions and user preferences; (4) regulate the speed of the
condenser fans to control the condenser temperature thereby
obtaining the best compromise between increased fan motor power
consumption and increased compressor motor power; (5) regulate the
speed of the evaporator fan proportionate to the temperature
differential between the user temperature set point and the actual
ambient temperature; and (6) regulate the speed of the compressor
motor to maintain the desired evaporator temperature.
[0070] The power management controller 50 carries out its function
by being operationally connected to the battery management
controller 60, the user interface 51 (which includes a display 310
and one or more inputs 312), a plurality of sensors, and the
operational components of the HVAC system as show in FIG. 5(b). The
plurality of sensor detects a variety of parameters including: the
vehicle's interior ambient temperature detected by a temperature
sensor 304, the humidity of the vehicle's compartments by using a
humidity sensor 307, and noise and/or vibration from one or more
noise or vibration sensors 308.
[0071] As to the operational components of the HVAC system, the
power management controller 50 can run the motor 12 that drives the
compressor 14; the circulation blowers that blow the
temperature-controlled air into one or more designated compartments
(such as the vehicle compartment 23 and/or the sleeping compartment
27); the heaters for the heating system (such as the air heaters
272 and 274 from FIG. 1 or the heater 180 from FIG. 2); and the
control doors (if applicable) for the regulation of the
temperature. Additionally the power management controller 50 can
also switch any control valves to control the flow of refrigerants
(such as the valves 28 and 29 from FIG. 1 or the valves 184 and 184
from FIG. 2). In one embodiment, the motor 12 of the compressor 14
can be controlled by the power management controller 50 using a
closed loop proportional, integral, derivative (PID) control.
Similarly, the power management controller 50 can also control the
fan speed of the circulation blowers 210 and 212 via a pulse width
modulated (PWM) PID control loop that is independent of the control
for the compressor.
[0072] In one embodiment, the power management controller 50 can
modulate the speed of the motor 12, and thus can modulate the
capacity of the compressor 14 driven by the motor 12. The
modulation of the compressor can range between an upper compressor
capacity and a lower compressor capacity. The compressor capacity
can vary depending on the compressor capacity required to maintain
the evaporator 22 or 26 at the evaporator temperature T.sub.E as
commanded by the power management logic circuit 66.
[0073] In one exemplary embodiment of the present invention, the
power management controller 50 ("PMC") can work as described below
with reference to FIG. 7. The power management controller 50
receives a signal from the user interface 51 to begin operation at
step 702. Commands are sent to the battery management controller 60
("BMC") from the power supply management controller 50 to supply
power to the HVAC system 10 at step 704. The user interface 51 is
polled for the user preference settings, such as the mode of
operation, the location of temperature control, and the desired set
point temperature T.sub.sp. Also the ambient temperature T.sub.a is
read from the temperature sensor 304 at step 706.
[0074] If the user preference is for the "cooling" mode, the
process is sent to step 708 where a command is issued to start all
fans of the circulation blowers 210, 212 and the motor 12 of the
compressor 14 to a minimum speed. At step 710, the compressor speed
is then commanded to bring and hold the evaporator 22 to a
predetermined evaporator temperature T.sub.E if the vehicle
compartment is being cooled or to bring and hold the evaporator 26
to a predetermined evaporator temperature T.sub.E if the sleeping
compartment is being cooled. At step 712, the fans of the condenser
16 are commanded to bring and hold the condenser 16 to a
predetermined condenser temperature T.sub.C.
[0075] If the user preference is for the "heating" mode, a command
from the power management controller 50 is issued at step 714 to
start the fans of the circulation blowers of the evaporator 22 or
26. The electric heating element 270 or 274 is commanded at step
716 to a power level (via PWM control) proportionate to the fan
speed of the circulation blowers of the evaporator 22 or 26.
[0076] With the HVAC system 10 now running in either the heating or
cooling mode, the battery management controller 60 is polled for an
estimate of the run time based on the present power draw and stored
energy available for use in step 718. As step 720, the estimated
run time is compared to the desired run time which was programmed
into the user settings by the user using the user interface 51. The
power management controller factors the difference between the
estimated and desired run times into planning the output of the
HVAC system 10 to ensure that sufficient power is available for the
duration of the heating or cooling period (also called the "run
time plan"). Based on the run time plan, the power management
controller 50 may increase or decrease the average capacity of the
HVAC system periodically throughout the cycle. In particular, if
the amount of heating (steps 726 and 736) or the amount of cooling
(steps 726, 728, and 730) would require too much power to be drawn
from the power source(s), the highest capacity of the HVAC system
10 possible would be employed which would still allow the battery
management controller to supply power through the entire
operational period. The highest capacity possible can be obtained
through a combination of settings which would offer the best
efficiency for the prevailing conditions.
[0077] At step 722, a variety of measurements are taken at step 722
so as to ensure that the HVAC system runs efficiently with its
limited power supply. These measurements include the actual ambient
temperature of the vehicle's interior T.sub.a, the evaporator
temperature T.sub.E, and the condenser temperature T.sub.C. At step
722, temperature sensors on the evaporator measure the evaporator
temperature T.sub.E, temperature sensors on the condenser measure
the condenser temperature T.sub.C, sensors in the vehicle and/or
sleeping compartments measure the ambient temperature T.sub.a, and
the user inputs the desired ambient temperature or the set point
temperature T.sub.sp, via the user interface 51.
[0078] For efficient operation of the HVAC components in either the
cooling or heating mode, a calculation is made at step 724 in which
a difference .DELTA. between the ambient temperature T.sub.a and
the set point temperature T.sub.sp is determined. Then, the
circulation blowers at the evaporator 22 or 26 are commanded to a
speed proportionate to the difference .DELTA. at step 726. The
determination of an appropriate fan speed for the blowers at the
evaporator based on a given .DELTA. can be based on any one of a
number of methods known in the art such as tabular formulations or
computer models.
[0079] The air blown into the vehicle and/or sleeping compartments
affects the ambient temperature of the compartment; thus with
continued operation of the HVAC system, the difference (.DELTA.)
between the ambient temperature T.sub.a and the set point
temperature T.sub.sp begins to decrease. As the ambient temperature
T.sub.a nears the set point temperature T.sub.sp, the power
management controller 50 reduces the fan speed of the circulation
blowers at the evaporator 22 or 26 proportionately based on
.DELTA., as seen in step 726. If the system is in the cooling mode,
the reduced air flow over the evaporator 22 or 26 causes the
evaporator temperature T.sub.E to fall. In response, the power
management controller 50 adjusts the speed of the motor 12 that
drives the compressor 14 to maintain the desired evaporator
temperature T.sub.E at step 728. Similarly, the changing capacity
of the evaporator 22 or 26 also changes the temperature of the
condenser T.sub.C. Again, the power management controller 50
adjusts the fan speed of the condenser 16 so as to maintain the
desired condensing temperature T.sub.C at step 730. However, the
settings for the circulation blowers, the compressor, and the
condenser (which are set in steps 726, 728, and 730 respectively)
are subject to the highest possible capacity of the HVAC system
based on the run time plan. Thus, if too much power would be drawn
by these components while running at the most efficient operation,
the settings of these components would be adjusted so as to allow
the system to run for the desired run time while operating as close
as possible to the most efficient operation determined by
.DELTA..
[0080] The process continues to step 732 where the power management
controller receives data from the battery management controller 60
about whether there is sufficient power being supplied. If there is
sufficient power (the "YES" path), the process returns to step 718
and the process is repeated. If there is insufficient power (the
"NO" path), the operation of the HVAC system is terminated at step
734.
[0081] If the HVAC system is operating in heating mode rather than
the cooling mode, the power management controller 50 alters the PWM
cycle of the resistive heating elements 270 or 274 to match the
changing fan speed of the circulation blower at the evaporator 22
or 26. In this way, the temperature of the discharged air remains
constant. Thus, step 736 is carried out in FIG. 7 instead of steps
728 and 730. Similar with the cooling operation, the settings for
the circulation blowers and the heater (which are set in steps 726
and 736 respectively) are subject to the highest possible capacity
of the HVAC system based on the run time plan. Thus, if too much
power is being drawn by these components while running at the most
efficient operation, the settings of these components can be
adjusted so as to allow the system to run for the desired run time
while operating as close as possible to the most efficient
operation determined by .DELTA.. For example, the settings of the
circulation blowers may be lowered to a level that permits
operation during the entire desired run time while still operating
as close as possible to the settings for the most efficient
operation based on .DELTA..
[0082] Other system parameters can be used to control the
motor-driven compressor 14 and the circulation blowers 210 and 212.
For example, the power management controller 50 can also monitor
humidity of the vehicle's compartments by using a humidity sensor
307. If the humidity of the compartments is above a predetermined
threshold (which can be set by the vehicle occupant), the power
management controller 50 can control the compressor 14 to speed up
(up to but not exceeding the upper compressor capacity) and the
circulation blowers 210 and 210 to slow down.
[0083] Furthermore, one or more noise or vibration sensors 308 can
be used to determine the level of noise or vibration of the HVAC
system 10. Once the signal is sent to the power management
controller 50, the controller 50 determines whether there is a need
to speed up or slow down the compressor and/or blower, and to
control the compressor and/or blower accordingly.
[0084] The use of one or more system parameters, such as the
evaporator temperature, the humidity, the exterior ambient
temperature, the vehicle's interior temperature, etc. to control
the compressor and blower capacities can be accomplished by
monitoring the one or more system parameters and using a program in
the power management controller 50 that was compiled using, for
example, a multivariate model known in the art.
[0085] Other system parameters can also be provided to the power
management controller 5, which may allow the power management
controller 50 to detect faults within the HVAC system. For example,
performance and safety functions are monitored and an appropriate
response by the power management controller 50 can be initiated,
such as shutting down the system in the event of the overheating of
the motor 12 of the compressor 14.
[0086] FIG. 9 shows another embodiment of the HVAC system according
to the present invention. The embodiment in FIG. 9 is similar to
the embodiment of FIG. 1; however, FIG. 9 shows how the HVAC system
can be divided up into a split system 600 in which there is an
exterior subsystem 602 and an interior subsystem 604. The exterior
subsystem 602 can comprise components that are located on the
exterior of the vehicle's cab. The interior subsystem 604 can
comprise components that are located in the interior of the
vehicle's cab. For example, FIG. 9 shows an exterior subsystem 602
that comprises a motor 12, a compressor 14, a condenser 16, and a
first power source, which are located outside the cab of a large
vehicle, such as a truck. In addition, the second power source and
the electrical power generation system 44 can also be located on
the exterior of the vehicle's cab as is conventional with large
vehicles.
[0087] The interior subsystem 604 can comprise the circulation
blower 610, the evaporator 622 and the power management controller
50, the battery management controller 60, the display 310, and the
input device 312, which are all located inside the cab of the
vehicle. The temperature controlled air can be optionally channeled
into ducts 672, which may split into two or more ducts that may
lead to different compartments or areas of the interior of the
vehicle's cab. In one embodiment, the ducts 672 can be the
vehicle's own ducting which is already installed in the vehicle
cab. Additionally, the interior subsystem 604 can comprise the
vehicle's already existing evaporator 622 and circulation blower
610. In such a situation, the exterior subsystem 602 may be
configured to be able to connect to a plurality of different
evaporators, such as the vehicle's own evaporator. In addition, the
exterior subsystem 602 may be configured to connect to a plurality
of evaporators at one time, such as one evaporator for
cooling/heating the driving compartment and one evaporator for
cooling/heating the sleeping compartment.
[0088] In FIG. 9, the refrigerant metering device is located
exterior to the vehicle's cab as part of the exterior subsystem
602, which allows the servicing of the metering device to be easier
if it should fail. Alternatively, the refrigerant metering device
20 can be located in the interior of the cab as part of the
interior subsystem 604.
[0089] The split system 600 has several advantages. First, less
interior space is taken up by the system because a substantial
portion of the components are located exterior to the vehicle's
cab. Additionally, the vehicle's existing ducts can be used so that
no additional ducting is needed. Thus, the system can have an
easier installation process, improved efficiency, and quieter
operation.
[0090] The disclosed battery management controller and HVAC system
can provide temperature control to a vehicle occupant for extended
periods of time when the vehicle's engine is not running. In
addition, the system ensures sufficient battery power to start the
vehicle even when the HVAC system has been running for a period of
time when the engine has been turned off. The battery management
and HVAC systems can be used in large trucks, such as 18 wheelers,
as well as any other type of vehicle.
[0091] During operation, the power management controller 30
processes the user inputs to determine the operational mode of the
HVAC system 10. When either the heating or cooling mode of
operation is selected and when the engine is turned on, the vehicle
electrical power generation system is used to power the necessary
components. For example, the heater and circulation blowers are
turned on during the heating mode of operation while the
compressor, circulation blowers, and pumps are turned on during the
cooling mode of operation.
[0092] When the heating mode is operating when the engine is turned
off, the power management controller 50 commands a heater (such as
the coolant heater 180 in FIG. 2 or the air heaters 270 and 274 in
FIG. 1) and the circulation blowers 210 and 212 to turn on. The
power management controller 50 also controls the speed of the
circulation blowers 210 and 212 via a pulse width modulated (PWM)
PID control loop in order to maintain the temperature of the
driving and/or sleeping compartment at the interior set point
temperature. With the various disclosed embodiments, the heating of
the interior of the cab can be performed without relying on diesel
fuel but can be run purely by battery power. Thus, the heating can
be performed without relying on the vehicle's engine being turned
on.
[0093] When the cooling mode of operation is used when the engine
is turned off, the circulation blowers 210 and 212, the compressor
14 and/or the pump 176 are turned on. The power management
controller 50 modulates the capacity of the compressor 14 and the
circulation blowers 210 and 212 to maintain the temperature of the
driving and/or sleeping compartment at the interior set point
temperature via PID control.
[0094] In either the heating or cooling mode when the engine is
turned off, if the voltage of the combination of the first and
second power sources drops below a predetermined amount, the first
and/or second power source is disconnected and the HVAC system is
only powered by the remaining power source. Once the voltage of the
remaining power source drops below another predetermined level, the
battery management controller 60 can be configured to disconnect
the remaining power source, thus shutting down the HVAC system
10.
[0095] Upon start up of the vehicle, the alternator or other
charging device can be used to charge up the first and second power
sources (if they are batteries) so that they are fully charged. In
one embodiment of the present invention, the battery management
controller 60 can also be used to connect the first power source
(such as an auxiliary battery or bank of auxiliary batteries)
during the start up of the vehicle in the situation where the
second power source (such as the starter battery or bank of
batteries) is too weak to start the vehicle, such as in the case
where the starter battery is weakened because of very low exterior
ambient temperatures.
[0096] Furthermore, the HVAC system can be a split system with a
substantial portion of the components exterior to the vehicle's cab
such that less interior space is taken up by the HVAC system. Also,
the vehicle's existing evaporator and/or ducting can be used with
the HVAC system for an easier installation process, improved
efficiency, and quieter operation.
[0097] Given the disclosure of the present invention, one versed in
the art would appreciate that there may be other embodiments and
modifications within the scope and spirit of the invention.
Accordingly, all modifications attainable by one versed in the art
from the present disclosure within the scope and spirit of the
present invention are to be included as further embodiments of the
present invention. The scope of the present invention is to be
defined as set forth in the following claims.
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