U.S. patent application number 12/202166 was filed with the patent office on 2010-03-04 for climate control systems and methods for a hybrid vehicle.
This patent application is currently assigned to PACCAR INC. Invention is credited to William C. Kahn, Glen A. Marshall.
Application Number | 20100050671 12/202166 |
Document ID | / |
Family ID | 41092034 |
Filed Date | 2010-03-04 |
United States Patent
Application |
20100050671 |
Kind Code |
A1 |
Kahn; William C. ; et
al. |
March 4, 2010 |
CLIMATE CONTROL SYSTEMS AND METHODS FOR A HYBRID VEHICLE
Abstract
Climate control systems are provided that are suitable for
providing climate control functionality to a hybrid vehicle. The
system is capable of operating in dual modes, depending on the
present operational state of the vehicle. For example, the dual
modes may be as follows: (1) when the vehicle is currently in
transit, including intermittent stops, the climate control system
is capable of operating at its maximum output, as requested, for
cooling the passenger compartment of the vehicle; and (2) when the
vehicle is not in transit (e.g., when parked) the climate control
system operates at a reduced capacity in order for the climate
control system to be powered by the energy storage device for a set
period of time. The climate control system may reduce the capacity
based on energy reserve levels in the energy storage device.
Inventors: |
Kahn; William C.; (Denton,
TX) ; Marshall; Glen A.; (Denver, IA) |
Correspondence
Address: |
CHRISTENSEN, O'CONNOR, JOHNSON, KINDNESS, PLLC
1420 FIFTH AVENUE, SUITE 2800
SEATTLE
WA
98101-2347
US
|
Assignee: |
PACCAR INC
Bellevue
WA
|
Family ID: |
41092034 |
Appl. No.: |
12/202166 |
Filed: |
August 29, 2008 |
Current U.S.
Class: |
62/190 |
Current CPC
Class: |
B60H 2001/3266 20130101;
B60H 1/00378 20130101; B60H 1/004 20130101; B60H 2001/3292
20130101; B60H 2001/327 20130101; B60H 1/3208 20130101 |
Class at
Publication: |
62/190 |
International
Class: |
F25D 17/06 20060101
F25D017/06 |
Claims
1. A climate control system for a hybrid heavy duty vehicle having
an engine-on condition while driving and an engine-off condition
while parked, comprising: an electrically powered compressor; an
energy storage device connected in electrical communication with
the electrically powered compressor for supplying power thereto; at
least one sensor capable of outputting signals indicative of an
engine-on condition or an engine-off condition; and a controlling
component operable to receive the signals of the at least one
sensor, and based on said signals and energy storage level data
from the energy storage device, operate to selectively control the
power supplied to the electrically powered compressor so as to
provide a first compressor output level during a vehicle engine-on
condition and a second, lower, compressor output level during a
vehicle engine-off condition, wherein the second compressor output
level is selected so as to allow the compressor to operate at a
lower output as compared to the first compressor output level for a
predetermined period of time.
2. The climate control system of claim 1, wherein the controlling
component is a software component located on a hardware device.
3. The climate control system of claim 1, wherein the controlling
component is hardware circuitry
4. The climate control system of claim 1, wherein the signals
indicative of an engine-on condition are selected from the group of
signals consisting of a transmission gear signal, an engine speed
signal, a transmission input speed signal, transmission output
speed signal, and a wheel speed signal.
5. The climate control system of claim 1, wherein the signals
indicative of an engine-off condition are selected from the group
of signals consisting of a parking brake signal, a transmission
gear signal, an ignition switch signal, and a mode switch
signal.
6. A hybrid vehicle having an engine-on condition while driving and
an engine-off condition while parked, comprising: a fuel powered
engine having an engine-on condition and an engine-off condition; a
motor; a first controlling component for controlling the operation
of the fuel powered engine and the motor; wherein the first
controlling component controls the transition of the fuel powered
engine between the engine-on condition and the engine-off
condition; an electrically powered compressor; an energy storage
device connected in electrical communication with the electrically
powered compressor for supplying power thereto; at least one sensor
capable of outputting signals indicative of an engine-on or an
engine-off condition; and a second controlling component operable
to receive the signals of the at least one sensor, and based on
said signals and a state of charge of the energy storage device,
operate to selectively regulate the power supplied to the
electrically powered compressor so as to provide a first compressor
output level during a vehicle engine-on condition and a second,
lower, compressor output level during a vehicle engine-off
condition, wherein the second compressor output level is selected
so as to allow the compressor to operate at a lower output as
compared to the first compressor output level for a predetermined
period of time.
7. The vehicle of claim 6, wherein the second controlling component
includes: a memory for storing data; and a processor
communicatively coupled to the memory, wherein the processor is
operative to: cause an accumulation in the memory of one or more
energy storage device data that is indicative of SOC; cause an
accumulation in the memory of one or more vehicle operating data
that is indicative of an engine-off condition; and based on said
energy storage data and said vehicle operating data, output control
signals to effect the amount of power to be transmitted to the
electrically powered compressor.
8. The vehicle of claim 7, wherein the data indicative of an
engine-off condition is selected from the group of data consisting
of a parking brake data, a transmission gear data, an ignition
switch data, and a mode switch data.
9. A climate control method for a vehicle having an electrical
compressor powered by an energy storage device, comprising the
steps of: obtaining a signal from an A/C power switch; obtaining
data regarding the current state of operation of the vehicle;
obtaining energy reserve level data of the energy storage device;
determining the energy level to be supplied to the electrical
compressor; and controlling the energy supplied to the electrical
compressor.
10. The method of claim 9, wherein the data regarding the current
state of operation of the vehicle includes data selected from the
group consisting of transmission gear data, an engine speed data,
transmission input speed data, transmission output speed data,
wheel speed data, parking brake data, ignition switch data, and
mode switch data.
Description
BACKGROUND
[0001] Air conditioning systems are well known for climate control
in vehicles. The compressors of these air conditioning systems in
conventional vehicles are belt driven by the internal combustion
engine. Therefore, when the internal combustion engine is turned
off, the A/C compressor is also turned off. Although not a problem
during the operation of conventional vehicles, this can pose a
problem when conventional vehicles and hybrid electric vehicles
(HEVs) are parked for long periods or during the operation of
hybrid HEVs because the internal combustion engine in such HEVs is
frequently shut off while the vehicle is stopped, for example, at a
stop light, or during low vehicle speeds (or low vehicle power
demands).
[0002] Air conditioning systems are important in Class 8 trucks,
which typically include a sleeper section as part of the cab for
providing sleeping or resting quarters for the operator during
government mandated rest periods. Historically, during these
periods, the internal combustion engine of the conventional truck
would idle in order to supply power for "house" loads and for
climate control systems, such as air conditioning units.
[0003] To address this deficiency, and in order to reduce fuel
consumption and to cut emissions, newer trucks employ a small
diesel powered generator so that the main engine need not idle
during these rest periods. However, these systems are not without
problems.
SUMMARY
[0004] This summary is provided to introduce a selection of
concepts in a simplified form that are further described below in
the Detailed Description. This summary is not intended to identify
key features of the claimed subject matter, nor is it intended to
be used as an aid in determining the scope of the claimed subject
matter.
[0005] In accordance with aspects of the present invention, a
climate control system is provided for a hybrid heavy duty vehicle
having an engine-on condition while driving and an engine-off
condition while parked. The system includes an electrically powered
compressor, an energy storage device connected in electrical
communication with the electrically powered compressor for
supplying power thereto, at least one sensor capable of outputting
signals indicative of an engine-on condition or an engine-off
condition, and a controlling component operable to receive the
signals of the at least one sensor, and based on the signals and
energy storage level data from the energy storage device, operate
to selectively control the power supplied to the electrically
powered compressor so as to provide a first compressor output level
during a vehicle engine-on condition and a second, lower,
compressor output level during a vehicle engine-off condition. The
second compressor output level may be selected so as to allow the
compressor to operate at a lower output as compared to the first
compressor output level for a predetermined period of time.
[0006] In accordance with another aspect of the present invention,
a hybrid vehicle is provided having an engine-on condition while
driving and an engine-off condition while parked. The vehicle
comprises a fuel powered engine having an engine-on condition and
an engine-off condition, a motor, and a first controlling component
for controlling the operation of the fuel powered engine and the
motor. The first controlling component can control the transition
of the fuel powered engine between the engine-on condition and the
engine-off condition. The vehicle also includes an electrically
powered compressor, an energy storage device connected in
electrical communication with the electrically powered compressor
for supplying power thereto, and at least one sensor capable of
outputting signals indicative of an engine-on or an engine-off
condition. The vehicle further includes a second controlling
component operable to receive the signals of the at least one
sensor, and based on the signals and a state of charge of the
energy storage device, operate to selectively regulate the power
supplied to the electrically powered compressor so as to provide a
first compressor output level during a vehicle engine-on condition
and a second, lower, compressor output level during a vehicle
engine-off condition. The second compressor output level may be
selected so as to allow the compressor to operate at a lower output
as compared to the first compressor output level for a
predetermined period of time.
[0007] In accordance with yet another aspect of the present
invention, a climate control method is provided for a vehicle
having an electrical compressor powered by an energy storage
device. The method comprises the steps of: obtaining a signal from
an A/C power switch; obtaining data regarding the current state of
operation of the vehicle; obtaining energy reserve level data of
the energy storage device; determining the energy level to be
supplied to the electrical compressor; and controlling the energy
supplied to the electrical compressor.
DESCRIPTION OF THE DRAWINGS
[0008] The foregoing aspects and many of the attendant advantages
of this invention will become more readily appreciated by reference
to the following detailed description, when taken in conjunction
with the accompanying drawings, wherein:
[0009] FIG. 1 is a partial schematic diagrammatic view of one
embodiment of a climate control system formed in accordance with
aspects of the present invention;
[0010] FIG. 2 is a schematic diagrammatic view of one suitable
vehicle in which the climate control system of FIG. 1 may be
employed;
[0011] FIG. 3 is a functional block diagrammatic view of one
embodiment of a vehicle-wide network or CAN formed in accordance
with aspects of the present invention; and
[0012] FIG. 4 is a flow diagram of one exemplary method implemented
by the climate control system in accordance with aspect of the
present invention.
DETAILED DESCRIPTION
[0013] Embodiments of the present invention will now be described
with reference to the drawings where like numerals correspond to
like elements. Embodiments of the present invention are generally
directed to climate control systems and methods suitable for use in
vehicles, such as Class 8 trucks. More particularly, embodiments of
the present invention are directed to climate control systems
having dual operating modes, which can be suitable for use with
vehicles of the hybrid type (e.g., gas-electric, diesel-electric,
etc.). As will be described in more detail below, the climate
control system functioning in the first mode is capable of
operating at a maximum output in transit, and functioning in the
second mode is capable of operating at a lower output than the
first mode as a result of present operating parameters of the
vehicle (e.g., the vehicle is parked).
[0014] Although exemplary embodiments of the present invention will
be described hereinafter with reference to a hybrid powered heavy
duty truck, it will be appreciated that aspects of the present
invention have wide application, and therefore, may be suitable for
use with many other types of vehicles, including but not limited to
light & medium duty vehicles, passenger vehicles, motor homes,
buses, commercial vehicles, marine vessels, etc., that are hybrid
powered. Accordingly, the following descriptions and illustrations
herein should be considered illustrative in nature, and thus, not
limiting the scope of the present invention, as claimed.
[0015] Prior to discussing the details of various aspects of the
present invention, it should be understood that the following
description includes sections that are presented largely in terms
of logic and operations that may be performed by conventional
electronic components. These electronic components, which may be
grouped in a single location or distributed over a wide area, can
generally include processors, memory, storage devices, input/output
circuitry, etc. It will be appreciated by one skilled in the art
that the logic described herein may be implemented in a variety of
configurations, including but not limited to, analog circuitry,
digital circuitry, processing units, etc., and combinations
thereof. In circumstances were the components are distributed, the
components are accessible to each other via communication
links.
[0016] In the following description, numerous specific details are
set forth in order to provide a thorough understanding of exemplary
embodiments of the present invention. It will be apparent to one
skilled in the art, however, that many embodiments of the present
invention may be practiced without some or all of the specific
details. In some instances, well-known process steps have not been
described in detail in order not to unnecessarily obscure various
aspects of the present invention.
[0017] As briefly described above, embodiments of the present
invention are directed to climate control systems and methods
suitable for use in a vehicle. One suitable vehicle in which the
climate control systems may be employed will now be described in
more detail with reference to FIG. 2. Turning now to FIG. 2, there
is shown a vehicle 20, such as a Class 8 tractor, having one
suitable embodiment of a parallel hybrid powertrain 22. The vehicle
20 depicted in FIG. 2 represents one of the possible applications
for the systems and methods of the present invention. It should be
appreciated that aspects of the present invention transcend any
particular type of land or marine vehicle employing a hybrid
powertrain. Moreover, the hybrid powertrain 22 depicted in FIG. 2
has a parallel configuration, although hybrid powertrains with
series configurations, or combined hybrid configurations (i.e.,
hybrids that operate in some manner as a parallel hybrid and a
series hybrid) may also be employed.
[0018] One of ordinary skill in the art will appreciate that the
hybrid powertrain 22 and associated subsystems/components may
include many more components than those depicted in FIG. 2. For the
sake of brevity, these additional components have not be described
herein. However, it is not necessary that all of these generally
conventional components be shown or described in order to disclose
an illustrative embodiment for practicing the present invention, as
claimed.
[0019] In the embodiment shown in FIG. 2, the hybrid powertrain 22
includes an internal combustion engine 26, an electric
motor/generator 28, a power transfer unit 30, and a transmission
32. The hybrid powertrain 22 also includes a fuel source 36 or the
like that stores any suitable combustive fuel, such as gasoline,
diesel, natural gas, alcohol, etc. In use, the internal combustion
engine 26 receives fuel from the fuel source 36 and converts the
energy of the fuel into output torque. The powertrain 22 further
comprises an electrical energy storage device 38 in the form of a
high voltage battery, a bank of batteries or a capacitor.
Alternatively, a device such as a fuel cell may be used in
conjunction with a battery and/or capacitor to provide a source of
electrical power for the powertrain 22. In use, the electric motor
generator 28 can receive electrical energy from the energy storage
device 38 via a high voltage DC bus 40 and converts the electrical
energy into output torque. The electric motor generator 38 can also
operate as a generator for generating electrical energy to be
stored in the electrical energy storage device 38.
[0020] Still referring to FIG. 2, the power transfer unit 30
operatively interconnects the internal combustion engine 26, the
electric motor generator 28, and the transmission 32. The
transmission 32 may be a manual transmission, an automated manual
transmission, or an automatic transmission that includes multiple
forward gears and a reverse gear operatively connected to an output
shaft 42, and a neutral position that disconnects the output shaft
from the torque inputted into the transmission 32. The power
transfer unit 30 is configured for selectively switching between
multiple vehicle operating states, which include but are not
limited to: 1) a state where only the output torque of the engine
26 is transmitted through the transmission 32 to the output shaft
42; 2) a state where only the output torque generated by the
electric motor 28 is transferred through the transmission 32 to the
output shaft 42; 3) a state where the output torque of the internal
combustion engine 26 and the electric motor generator 28 is
combined and transferred through the transmission 32 to the output
shaft 42; and 4) a state where the internal combustion engine 26
transmits output torque to the output shaft 42 through the
transmission 32 and transmits output torque to the electric motor
generator 28 so that the electric motor generator 28 acts as a
generator for generating electrical energy to charge the energy
storage device 38. A regenerative braking state of vehicle
operation may also be provided by the power transfer unit 30, as
known in the art.
[0021] One or more clutch assemblies 44 may be positioned between
the internal combustion engine 26 and electric motor generator 28
and the power transfer unit 30 and/or the transmission 32 to
selectively engage/disengage the internal combustion engine 26
and/or electric motor generator 28 from the power transfer unit 30
and/or the transmission 32. The one or more clutch assemblies 44
may be part of the power transfer unit 30 or may be discrete
therefrom. In one embodiment, the power transfer unit 30 may
include a planetary gear set conventionally arranged for carrying
out the functions 1-4 described above. Of course, other types of
power transfer units, including other gear sets and transmissions,
may be employed. In another embodiment, the power transfer unit 30
and the transmission 32 may be arranged as a unitary device that
provides both the functions of the power transfer unit 30 and that
of the transmission 32. One type of unitary device that may be
employed by the powertrain 22 is known in the art as a power split
device.
[0022] The vehicle 20 also includes at least two axles such as a
steer axle 50 and at least one drive axle, such as axles 52 and 54.
The output shaft 42 of the transmission 32, which may include a
vehicle drive shaft 56, is drivingly coupled to the drive axles 52
and 54 for transmitting the output torque generated by the internal
combustion engine 26 and/or the electric motor generator 28 to the
drive axles 52 and 54. The steer axle 50 supports corresponding
front wheels 66 and the drive axles 52 and 54 support corresponding
rear wheels 68, each of the wheels having service brake components
70. The service brake components 70 may include wheel speed
sensors, electronically controlled pressure valves, and the like,
to effect control of the vehicle braking system.
[0023] The vehicle 20 may also include conventional operator
control inputs, such as a clutch pedal 72 (in some manual systems),
an ignition or power switch 74, an accelerator pedal 76, a service
brake pedal 78, a parking brake 80 and a steering wheel 82 to
effect turning of the front wheels 66 of the vehicle 20. The
vehicle 20 may further include a cab mounted operator interface,
such as a control console 84, which may include any of a number of
output devices 88, such as lights, graphical displays, speakers,
gages, and the like, and various input devices 90, such as toggle
switches, push button switches, potentiometers, or the like.
[0024] As will be described in more detail below, the input devices
90 may include an A/C control panel 92 and an optional mode switch
94. To provide power to the control console 84, a DC/DC converter
96 is connected to the high voltage bus 40. The DC/DC converter 96
reduces the voltage it receives, and outputs power at this lower
voltage to the control console. The DC/DC converter 96 can output
power to other low voltage electrical devices on the vehicle 20.
The DC/DC converter 96 may also condition the power prior to
directing it to the low voltage electrical devices.
[0025] To control the various aspects of the hybrid powertrain 22,
a powertrain controller 100 is provided. As shown in FIGS. 1 and 3,
the powertrain controller 100 can be a dedicated controller for the
hybrid powertrain 22 or can be incorporated in another general
vehicle controller, such as a vehicle system controller (VSC).
Although the powertrain controller 100 is shown as a single
controller, it may include multiple controllers or may include
multiple software components or modules embedded in a single
controller. For example, the powertrain controller 100 could be a
separate hardware device, or may include a separate powertrain
control module (PCM), which could be software embedded within
general purpose controller, such as a VSC.
[0026] In one embodiment, the powertrain controller 100 may control
the operation of one or more of the following devices: the internal
combustion engine 26; the electric motor generator 28; the power
transfer unit 30; the transmission 32; the electrical storage
device 38, optional clutch assemblies 42, etc. In one embodiment,
the powertrain controller 100 may include a programmable digital
computer, microprocessor, or the like that is configured to receive
(and may store) various input signals, including without
limitation, the operating speeds of internal combustion engine 26
via sensor 102 and the electric motor generator 28 via sensor 104,
transmission input speed via sensor 106, selected transmission
ratio, transmission output speed via sensor 108 and vehicle speed
via wheel speed sensors (not shown), throttle position via sensor
110, and state of charge (SOC) of the energy storage device 38. The
powertrain controller 100 may store these signals for
contemporaneous or future use. The powertrain controller 100
processes these signals and others accordingly to logic rules to
control the operation of the hybrid powertrain 22. For example, to
start or restart the internal combustion engine 26, the powertrain
controller 100 may be programmed to signal delivery of fuel to the
internal combustion engine 26 and to signal the operation of the
electrical motor generator or optional starter to start the engine.
It will be appreciated that the powertrain 100 may receive these
input signals directly from the associated sensor(s), devices,
etc., or may receive the input signals from other vehicle
subsystems, as will be described in more detail below.
[0027] To support this control, various devices (e.g., the internal
combustion engine 26, the electric motor generator 28, etc.)
controlled by the powertrain controller 100 may include their own
controllers, which communicate with the powertrain controller 100
through a vehicle-wide network, also referred to as a controller
area network (CAN) 112, as shown in FIG. 3. Those skilled in the
art and others will recognize that the CAN 112 may be implemented
using any number of different communication protocols such as, but
not limited to, Society of Automotive Engineer's ("SAE") J1587, SAE
J1922, SAE J1939, SAE J1708, and combinations thereof.
Alternatively, the aforementioned controllers may be software
control modules contained within the powertrain controller 100 or
other general purpose controllers residing on the vehicle. It will
be appreciated, however, that the present invention is not limited
to any particular type or configuration of powertrain controller
100, or to any specific control logic for governing operation of
hybrid powertrain system 20.
[0028] For example, an engine controller 114 may communicate with
the powertrain controller 100 and may function to monitor and
control various aspects of the operation of the internal combustion
engine 26, including ignition timing (on some vehicles), fuel
delivery, variable valve timing (if equipped) and the like. To that
end, the engine controller 114 typically receives signals from a
variety of sensors, including but not limited to the wheel speed
sensors (not shown) of the brake components 70, the engine speed
sensor 102, the accelerator pedal position sensor 108, etc., either
directly or by other system or device controllers (i.e., a
transmission controller 116, a power transfer unit controller 118,
the powertrain controller 100, etc.), processes such signals and
others, and transmits a variety of control signals to devices
including but not limited to fuel control devices 120 for
selectively supplying fuel to the internal combustion engine 26, an
engine retarder 122, such as a jake brake, etc.
[0029] As will be described in more detail below, the engine
controller 114 may transmit signals indicative of vehicle
operational data (e.g., engine speed, throttle position, etc.) to
the powertrain controller 100 or other system controllers via the
CAN 112 and may receive control signals from the powertrain
controller 100 or from controllers of other vehicle subsystems
either directly or via CAN 112 to effect the operation of the
internal combustion engine 26.
[0030] Similarly, the electrical energy storage device 38 may have
a controller 124 that may communicate with the powertrain
controller 100 and may function to monitor and control various
aspects of the operation of the electrical energy storage device
38. To that end, the energy storage controller 124 sends and
receives signals to and from the powertrain controller 100 and the
electrical energy storage device 38. For example, the controller
124 may receive signals from a variety of sensors, etc., such as
voltage data, current data, charge and discharge data (e.g., in amp
hours), temperature data and/or other state of charge (SOC)
determination data etc., and appropriately processes such signals.
In one embodiment, the controller 124 continuously determines the
SOC of the electrical energy storage device 38. In another
embodiment, the controller 124 determines the SOC of the electrical
energy storage device 38 upon control signals sent by the
powertrain controller 100. In another embodiment, the controller
124 sends the processed signals to the powertrain controller 100,
where they are processed to determine, for example, the SOC of the
electrical energy storage device 38.
[0031] Moreover, the electric motor generator 28 may include one or
more controllers 126 that sends and receives signals to and from
the powertrain controller 100 and the electric motor generator 28
for controlling the direction of power flow to/from the electric
motor generator 28. The vehicle may include other controllers, such
as a braking system controller (not shown), as well known in the
art, communicatively connected to the CAN 112.
[0032] As used herein, controllers, control units, control modules,
program modules, etc., can contain logic for carrying out general
or specific operational features of the vehicle 20. The logic can
be implemented in hardware components, such as analog circuitry,
digital circuitry, processing units, or combinations thereof, or
software components having instructions which can be processed by
the processing units, etc. Therefore, as used herein, the term
"controlling component" can be used to generally describe these
aforementioned components, and can be either hardware or software,
or combinations thereof, that implement logic for carrying out
various aspects of the present invention.
[0033] Referring now to FIGS. 1 and 2, in one embodiment of the
present invention, the powertrain controller 100, either alone or
in conjunction with other controllers can control the operation of
the vehicle in the following manner. It will be appreciated that
the vehicle can be controlled to operate in any number of ways or
modes. Additionally, it should be appreciated that the following
description of the operation of the vehicle in accordance to one
embodiment relates to a parallel hybrid vehicle, and that the
operation of vehicles with serial hybrid powertrains, combined
hybrid powertrains, or power assist hybrids will be slightly
different.
[0034] When it is desired to start the hybrid vehicle 20 from rest
(i.e., parked), the ignition switch 74 is moved to the start
position. Next, the vehicle operator chooses the appropriate gear,
releases the parking brake 80, if set, lifts their foot off of the
service brake pedal 78, and applies pressure on the accelerator
pedal 76. At this time, the powertrain controller 100 monitors
various hybrid powertrain operating parameters, for example, the
SOC of the energy storage device 38 and the load state of the
vehicle 20, and depending on the SOC of the energy storage device
38 and the load state of the vehicle (typically calculated by
accelerator pedal position and/or vehicle speed), the powertrain
controller 100 controls the operation of the electric motor
generator 28 only ("electric launch mode"), the internal combustion
engine 26 only, or combines the output of both via the power
transfer unit 30 ("blended torque mode") to provide motive force to
the vehicle 20.
[0035] For example, if the powertrain controller 100 determines
that the SOC of the energy storage device 38 is at a sufficient
level with respect to the vehicle load state, the powertrain
controller 100 operates the powertrain 22 in the electric launch
mode. For example, in a low load state and/or a low vehicle speed,
and a high SOC, the powertrain controller 100 operates solely in
the electric launch mode. In the electric launch mode, the internal
combustion engine 26 is off (engine-off condition), and the
powertrain controller 100 signals delivery of electrical energy
from the electrical energy storage device 38 to power the electric
motor generator 28. Upon receipt of electrical power from the
electrical energy storage device 38, the electric motor generator
28 acts as a motor to generate output torque for propelling the
vehicle 20.
[0036] On the other hand, if the powertrain controller 100
determines that the SOC of the energy storage device 38 is low with
respect to the calculated vehicle load state, the powertrain
controller 100 operates the powertrain 22 either in the hybrid
assist mode, also known as the "blended torque mode," or the engine
only mode. In the blended torque mode, the power controller 100
signals delivery of electrical energy from the electrical energy
storage device 38 to power the electric motor generator 28 and fuel
delivery to the internal combustion engine 26 so as to be started
by the electric motor generator 28, and then signals the internal
combustion engine 26 and the energy storage device/electric motor
generator to generate output torque, which is "blended" or combined
by the power transfer unit 30 according to control signals from the
powertrain controller 100. For example, in a medium load state
where the powertrain controller 100 determines that improved fuel
efficiency may be realized by operating in the blended torque mode,
or if additional torque is needed from the electric motor generator
28 during, for example, rapid acceleration situations, the internal
combustion engine 26 and the electric motor generator 28 are
operated by the powertrain controller 100 so that the generated
output torque is combined by the power transfer unit 30 and sent to
the drive axles 52 and 54 through the transmission 32.
[0037] It should also be appreciated that the vehicle 20 may start
out in electric launch mode, but based on continuously monitored
operating conditions of the powertrain, e.g., SOC and vehicle load,
the powertrain controller 100 may determine that the internal
combustion engine 26 is needed to meet the output demands of the
vehicle 20. In this case, the powertrain controller 100 signals for
the internal combustion engine 26 to be started by the electric
motor generator 28 or a separate starter motor, and signals the
appropriate components, e.g., power transfer unit 30, clutch
assemblies 44, etc. to combine the output torque of the internal
combustion engine 26 and the electric motor generator 28 for
propelling the vehicle 20.
[0038] When the hybrid vehicle 20 is cruising (i.e. not
accelerating), and the internal combustion engine 26 can meet the
vehicle load demand, the powertrain controller 100 controls the
operation of the internal combustion engine 26, the electric motor
generator 28, and the power transfer unit 28 based on the SOC of
the energy storage device 38. If the energy storage device SOC is
low, the powertrain controller 100 operates the power transfer unit
30 to split the power from the internal combustion engine 26
between the drive axles 52, 54 and the electric motor generator 28
so that the electric motor generator 28 acts as a generator and
charges the energy storage device 38. This is called the "utility
regeneration" mode. If the SOC of the energy storage device 38 is
high, the powertrain controller 100 may operate the internal
combustion engine 26 solely to propel the vehicle, or may operate
the power transfer unit 32 and the electric motor generator 28 in
the blended torque mode, as described above.
[0039] At any time the powertrain controller 100 determines during
vehicle operation that the SOC of the energy storage device 38
becomes equal to or lower than a threshold level, the internal
combustion engine 26 is immediately driven, and the output torque
of the internal combustion engine 26 is transmitted to the electric
motor generator 28 through the power transfer device 30. In this
case, the electric motor generator 28 is operated as a power
generator to charge the energy storage device 38. This may occur
during vehicle transit or idling situations as well.
[0040] The energy storage device 38 may also be charged during
vehicle movement via the regenerative braking mode. That is,
instead of using the brakes to slow or stop the vehicle 20, the
electric motor generator 28 is used to slow the vehicle 20. At the
same time, the energy from the rotating rear wheels 68 is
transferred to the electric motor generator 28 via the transmission
32 and power transfer unit 30 (the internal combustion engine 26 is
either in the engine-off mode or is decoupled from the power
transfer unit 30 by a clutch assembly 44), which in turn, causes
the electric motor generator 28 to act as a generator to charge the
energy storage device 38.
[0041] Referring now to FIG. 1, there is shown a block diagrammatic
view of one embodiment of a climate control system, generally
designated 140, formed in accordance with aspects of the present
invention. The climate control system 140 is suitable for use in a
vehicle, such as the vehicle 20 described above, for providing
climate control functionality to a hybrid vehicle. As will be
described in more detail below, the system 140 is capable of
operating in dual modes, depending on the present operational state
of the vehicle. In one embodiment, the dual modes are as follows:
(1) when the vehicle is currently in transit, including
intermittent stops, the climate control system 140 is capable of
operating at its maximum output, as requested, for cooling the
passenger compartment of the vehicle; and (2) when the vehicle is
not in transit (e.g., when parked) the climate control system 140
operates at a reduced capacity in order for the climate control
system to be powered by the energy storage device 38 for a set
period of time. As will be described in more detail below, the
climate control system 140 reduces the capacity based on energy
reserve levels in the energy storage device 38.
[0042] As best shown in the embodiment of FIG. 1, the climate
control system 140 generally includes an air conditioning unit 142
for performing air-conditioning control in a passenger compartment
of the vehicle 20, such as the cab and/or sleeper section of a
Class 8 truck. The climate control system 140 also includes air
conditioning controller 144 for controlling components of the air
conditioning unit 142 via inputs from the air conditioning (A/C)
control panel 92, the ignition switch 74, and/or the optional mode
switch 94. In one embodiment, the air conditioning unit 142 may be
an automatic-controlled air conditioner where the temperature in
the passenger compartment is automatically controlled at a
temperature set arbitrarily by the operator. Alternatively, the air
conditioning unit 142 may be a manually controlled air conditioner
where the temperature in the passenger compartment is manually
controlled by the operator though manipulation of inputs on the
control panel 92.
[0043] As shown in FIG. 1, the air conditioning unit 142 generally
includes a refrigerant cycle system 160 that lowers the temperature
of air flowing via a blower (not shown) through air-conditioning
ducting of the vehicle and into the passenger compartment. In one
embodiment, the refrigerant cycle system 160 general includes an
electrical compressor 166, a condenser 168, an expansion valve 172,
and an evaporator 176 operatively connected in a conventional
manner. The air conditioning unit 142 may include other components
not shown but well known in the art, such as a heater core, a
gas-liquid separator, an accumulator, air mix dampers, air
directional dampers or diverters, etc.
[0044] In the embodiment shown, the electrical compressor 166
includes an electric motor 180 for driving a compression mechanism
(not shown) using electrical power from the electrical energy
storage device 38. To that end, the electrical compressor 166 is
electrically connected to the high voltage DC Bus 40 via a variable
output DC to DC converter 184, which outputs a variable DC voltage
based on instructions from the air conditioning controller 144. The
electrical compressor 166 is sized to replace the engine driven
unit of conventional vehicles. In one embodiment, the electrical
compressor 166 has a variable capacity of up to about 33,000
BTU/hour, although higher or lower capacity compressors may be used
by embodiments of the present invention, as claimed.
[0045] While a variable DC voltage is applied to the compressor
motor 180 via the DC to DC converter 184 to control the output of
the air conditioning unit 142, it will be appreciated that in
another embodiment, an alternating-current (AC) voltage may be
applied to an appropriately configured electrical motor, such as an
AC induction motor, through an inverter, which is configured for
adjusting a frequency of the AC voltage based on instructions from
the air conditioning controller 144. Thus, the rotation speed of
the electrical compressor 166 can be continuously changed.
[0046] As best shown in FIG. 1, the air conditioning controller 144
is connected in electrical communication with the control panel 92,
the optional mode switch 94 and/or the vehicle ignition switch 74,
one or more sensors 182 (e.g., temperature sensors), and the DC to
DC converter 184. In use, the Air conditioning controller 144
receives input signals from the control panel 92, the one or more
sensors 182 and/or other input signals, the optional mode switch 94
or the vehicle ignition switch 74, processes these signals and
others according to logic rules to be described in detail below,
and transmits control signals to the DC to DC converter 184 in
order to control the amount of energy transmitted to the electrical
compressor 166.
[0047] It will be appreciated that the one or more sensors 182,
switches 74 and 94, etc., or other control inputs from the control
panel 92 may transmit their signals directly to the air
conditioning controller 144, as shown in FIG. 1, or may communicate
with the air conditioning controller 144 via the CAN 102. It will
be appreciated that the air conditioning controller 144 may
communicate with other electronic components of the vehicle 20 over
the CAN 102 for collecting data from other electronic components to
be utilized by the air conditioning controller 144. For example,
the engine controller 114 or powertrain controller 100 may output
one or more signals indicative of an engine-off condition (the
engine is not producing output torque) to the air conditioning
controller 144 via the CAN 112 so that the air conditioning
controller 144 may adjust the operation of the climate control
system 140. Similarly, the transmission controller 116 or
powertrain controller 100 may output a signal indicative of the
present gear of the transmission (e.g., reverse, 1st, 2nd, etc.,
neutral, or park (if so equipped). Similarly, the electrical energy
storage controller 124 or powertrain controller 100 may transmit a
signal indicative of energy reserves (e.g., ampere hours), so that
the air conditioning controller 144 may adjust the operation of the
climate control system 140. This energy reserves signal may include
a SOC signal, a current draw signal, and/or a voltage signal, etc.
The air conditioning controller 144 may receive other signals for
assisting the control of the air conditioning unit 140, such as a
signal from a parking brake sensor 186, a signal from a service
brake sensor 188, etc.
[0048] As shown in FIG. 1, the control panel 92 may include a
plurality of inputs, such as switches, knobs, levers, etc., to
operate the air conditioning unit 142. In one embodiment, the
control panel 92 includes an A/C on/off switch 190, a temperature
selector input 192, a blower fan selector input 194, and an
air-outlet mode input 196. The A/C on/off switch 190 operates to
start and stop the electrical compressor 166. The temperature
setting input 192 sets the temperature in the passenger compartment
at a requested temperature. The blower fan selector input 194
dictates the amount of air blown by the blower fan (not shown), and
the air-outlet mode input 196 changes the discharge direction of
the cooled air between a bi-level mode, a foot mode, a face mode, a
foot/defroster mode, and a defroster mode. The optional mode switch
94 may be activated by the vehicle operator to indicate that the
vehicle 20 is in an engine-off condition.
[0049] As shown in FIGS. 1 and 3, the air conditioning controller
144 is a separate controller dedicated to the climate control
system 140. However, it will be appreciated that the air
conditioning controller 144 may be an A/C control module, which
could be software embedded within an existing on-board controller,
such as the engine controller 114, a general purpose controller,
such as a cab mounted controller, that controls multiple subsystems
of the vehicle, or the powertrain controller 100.
[0050] In several embodiments, the air conditioning controller 144
and any one of the various motors, sensors, switches, actuators,
etc. of the climate control system 140 may contain logic rules
implemented in a variety of hardware circuitry components and/or
programmed microprocessors to effect control of the climate control
system 140 described herein. To that end, as further illustrated in
FIG. 1, one suitable embodiment of the air conditioning controller
144 includes a memory 200 with a Random Access Memory ("RAM") 204,
and an Electronically Erasable, Programmable, Read-Only Memory
("EEPROM") 206, a processor 208, and an A/C control module 210 for
providing functionality to the climate control system. The module
210 includes executable instructions that provide at least the
following functions: 1) general control over the climate control
system 140; and 2) specific control over the output of the electric
compressor 166, as will be described in detail below.
[0051] Those skilled in the art and others will recognize that the
EEPROM 206 is a non-volatile memory capable of storing data when
power is not supplied to the controller 144. Conversely, the RAM
204 is a volatile form of memory for storing program instructions
that are accessible by the processor 208. Typically, a fetch and
execute cycle in which instructions are sequentially "fetched" from
the RAM 204 and executed by the processor 208 is performed. In this
regard, the processor 208 is configured to operate in accordance
with program instructions that are sequentially fetched from the
RAM 204.
[0052] Turning now to FIG. 4, there is shown a flow diagram of one
exemplary embodiment of a climate control method 400 formed in
accordance with aspects of the present invention that may be
carried out by the air conditioning controller 144. The method 400
starts at block 402 and proceeds to block 404. At block 404, the
air-conditioning controller 144 monitors various inputs of the
climate control system 140, such as the A/C on/off switch 190, one
or more control inputs, such as the temperature setting knob 194,
blower fan selector knob 196, etc.
[0053] Next, at block 206, the Air conditioning controller 144
determines whether or not the A/C on/off switch 190 is activated.
If the determination is "no," the method returns to block 404. If
the controller 144 determines that the A/C on/off switch 190 is
activated, the method proceeds to block 208. At block 208, the air
conditioning controller 144 determines whether the vehicle 20 is in
transit or whether the vehicle is parked. To determine whether the
vehicle 20 is in transit or whether it is parked, the Air
conditioning controller 144 passively receives or actively
retrieves data from one or more sensors, switches, etc., regarding
current or recent vehicle operating data.
[0054] For example, the Air conditioning controller 144 may obtain
data from the engine output speed sensor 102, the transmission
input speed from sensor 106, transmission output speed via sensor
108, or vehicle wheel speed via wheel sensors (not shown). The air
conditioning controller 144 may receive other data, including the
presently selected transmission gear (e.g., park, 1.sup.st,
2.sup.nd, etc.) or may obtain data from the parking brake sensor
186 indicating whether the parking brake 80 is activated. The air
conditioning controller 144 may further receive data from the
ignition switch 74 and the optional mode switch 194. For example,
in some embodiments, the ignition switch 74 in the accessory (ACC)
position or activation of the mode switch 94 indicates that the
vehicle 20 is in a non-transit condition. It will be appreciated
that the air conditioning controller 144 may receive these signals
directly from the sensors, switches, and the like, or may receive
such signals, some appropriately processed, from the engine
controller 114, transmission controller 116, powertrain controller
100, etc. via the CAN 112.
[0055] If it is determined that the vehicle is in transit, the
method 400 proceeds to block 410, where the electrical compressor
166 is operated at its full capacity, if necessary, in order to
lower the temperature in the passenger compartment of the vehicle
as selected by temperature setting input 192. If it is determined
that the vehicle is parked, the method proceeds to block 412, where
the air conditioning controller 144 passively receives or actively
retrieves one or more signals indicative of the energy reserve
level of the energy storage device 38. The one or more signals may
include voltage data, SOC data, etc. It will be appreciated that
the air conditioning controller 144 may obtain the one or more
signals either directly from the energy storage device controller
126 or from other controllers or devices, such as the powertrain
controller 100 via the CAN 102.
[0056] Next, at block 414, the energy reserve level data is used to
determine the amount of energy to be transmitted to the compressor
166 via a power control device, e.g., DC to DC converter 184, AC
inventor (not shown). It will be appreciated that the amount of
energy supplied to the compressor 166 is less that the maximum
capacity that could be sent during transit. In several embodiments,
in order to aid in the determination of the amount of the energy to
be transmitted, other information may be utilized. For example, the
air conditioning controller 144 may obtain signals indicating
current power demands from other operating vehicle systems, such as
the entertainment system, e.g., radio, television, video player,
etc., CB, GPS, and the like. The air conditioning controller 144
may also use signals generated from the A/C control panel 92, such
as the temperature setting input 192, the blower fan selector input
194, etc., and from one or more temperature sensors 182, which
indicate the amount of cooling desired by the vehicle operator, and
the load created by the environmental conditions of the passenger
compartment.
[0057] Based on these signals and/or others, as desired, the air
conditioning controller 144 determines the energy level to be
transmitted to the electrical compressor 166. The air conditioning
controller 144 may determine the energy level as a percentage,
e.g., 20%, of the remaining energy level so that the electrical
compressor 166 may continuously operate to provide cooling to the
passenger compartment for a given period of time. The percentage
may be constant throughout its operation, or may be graduated lower
as the energy reserve levels decrease. It will be appreciated that
other methods may be used to calculate the energy transmitted to
the electrical compressor 166.
[0058] Once the amount of energy to be transmitted to the
electrical compressor 166 is calculated, the method 400 proceeds
from block 414 to block 416, where suitable controls signals are
generated based on the energy level determination made by the air
conditioning controller 144 and transmitted to the power control
device, such as the DC to DC converter 184, for controlling the
energy supplied to the electrical compressor 166. The method 400
ends at block 418. It will be appreciated that the method 400 may
include other steps, such as shutting off the power supplied to the
electrical compressor 166 when the energy levels of the energy
storage device 38 are below a preset threshold level. The threshold
level may be selected at a sufficient level to start the internal
combustion engine for recharging.
[0059] As a result, when the vehicle is parked (and the engine is
shut off), the climate control system 140 automatically limits the
energy into the air conditioning unit 142 to a preset amount of
present energy storage device capacity. This allows the energy
storage device 38 to perform for a predetermined period of time
prior to recharging. On the other hand, when the vehicle is in
transit (i.e., not parked), the climate control system 140 operates
at maximum capacity. This occurs either when the vehicle is in
motion, or when the vehicle is intermittently stopped, for example,
at a stop light, stop sign, or the like.
[0060] The principles, representative embodiments, and modes of
operation of the present invention have been described in the
foregoing description. However, aspects of the present invention
which are intended to be protected are not to be construed as
limited to the particular embodiments disclosed. Further, the
embodiments described herein are to be regarded as illustrative
rather than restrictive. It will be appreciated that variations and
changes may be made by others, and equivalents employed, without
departing from the spirit of the present invention. Accordingly, it
is expressly intended that all such variations, changes, and
equivalents fall within the spirit and scope of the present
invention, as claimed.
* * * * *