U.S. patent application number 14/260412 was filed with the patent office on 2015-10-29 for electric vehicle control based on operating costs associated with power sources.
This patent application is currently assigned to Ford Global Technologies, LLC. The applicant listed for this patent is Ford Global Technologies, LLC. Invention is credited to Kerry Eden Grand, Ming Lang Kuang, Venkatapathi Raju Nallapa, Fazal Urrahman Syed.
Application Number | 20150307082 14/260412 |
Document ID | / |
Family ID | 54261990 |
Filed Date | 2015-10-29 |
United States Patent
Application |
20150307082 |
Kind Code |
A1 |
Nallapa; Venkatapathi Raju ;
et al. |
October 29, 2015 |
ELECTRIC VEHICLE CONTROL BASED ON OPERATING COSTS ASSOCIATED WITH
POWER SOURCES
Abstract
A plug-in hybrid electric vehicle operates the engine and/or
traction motor in response to energy costs or prices received from
an external source, such as a user or network. The vehicle can
include a battery; an engine; an electric motor; a memory to store
a battery charge point, and a controller to modify the battery
charge point in response to arbitration criteria to control battery
charging from the engine. The arbitration criteria can be based at
least partially on fuel cost for the engine. The arbitration
criteria can be based at least partially on electricity cost. The
arbitration criteria can also include location of the vehicle. The
controller may alter a deadband between charging the battery with
the engine and discharging the battery to power the traction motor
based on the arbitration criteria.
Inventors: |
Nallapa; Venkatapathi Raju;
(Dearborn, MI) ; Grand; Kerry Eden; (Chesterfield,
MI) ; Syed; Fazal Urrahman; (Canton, MI) ;
Kuang; Ming Lang; (Canton, MI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Ford Global Technologies, LLC |
Dearborn |
MI |
US |
|
|
Assignee: |
Ford Global Technologies,
LLC
Dearborn
MI
|
Family ID: |
54261990 |
Appl. No.: |
14/260412 |
Filed: |
April 24, 2014 |
Current U.S.
Class: |
701/22 ;
180/65.265; 903/930 |
Current CPC
Class: |
Y02T 10/62 20130101;
Y02T 90/12 20130101; B60L 53/64 20190201; B60W 20/13 20160101; B60W
20/11 20160101; B60W 2510/244 20130101; B60W 2710/0677 20130101;
B60W 2900/00 20130101; B60L 53/665 20190201; Y10S 903/93 20130101;
Y02T 10/84 20130101; B60W 2530/00 20130101; B60W 2050/0064
20130101; B60W 2050/0005 20130101; B60W 10/06 20130101; B60W
2556/50 20200201; B60W 2050/0039 20130101; B60L 11/184 20130101;
Y02T 10/7072 20130101; B60W 10/08 20130101; B60W 10/26 20130101;
Y02T 10/70 20130101; B60W 2710/244 20130101; B60L 58/12
20190201 |
International
Class: |
B60W 20/00 20060101
B60W020/00; B60W 10/26 20060101 B60W010/26; B60W 10/08 20060101
B60W010/08; B60L 11/18 20060101 B60L011/18; B60W 10/06 20060101
B60W010/06 |
Claims
1. A plug-in hybrid electric vehicle, comprising: a battery; an
engine; an electric motor electrically connected to the battery; a
memory to store a battery charge set point, fuel cost, and
electricity cost; and a controller to control operation of the
engine and the electric motor based on the fuel cost and
electricity cost, wherein the controller modifies the battery
charge set point based at least partially on fuel cost for the
engine.
2. (canceled)
3. The electric vehicle of claim 1, wherein the controller modifies
the battery charge set point based at least partially on
electricity costs.
4. The electric vehicle of claim 1, wherein the controller modifies
the battery charge set point based at least partially on location
of the vehicle.
5. The electric vehicle of claim 1, wherein the controller is
configured to alter a deadband associated with the battery being
free from both charging by the engine and drawing power therefrom
in response to a change in at least one of fuel cost or electricity
cost.
6. A method for controlling a hybrid electric vehicle comprising:
operating an engine at a first fraction battery charge point
associated with at least one of fuel cost and electricity cost; and
operating the engine at a second traction battery charge point
different from the first traction battery charge point in response
to a change in at least one of the fuel cost and the electricity
cost.
7. The method of claim 6, further comprising receiving at least one
of the fuel cost and the electricity cost from a wireless
network.
8. The method of claim 6, further comprising modifying at least one
of the first traction battery charge point and the second traction
battery charge point in response to location of the vehicle.
9. The method of claim 6, further comprising: reducing a battery
state of charge threshold below which engine power is used to
charge the traction battery.
10. The method of claim 6, further comprising: raising a battery
state of charge threshold above which traction battery power is
requested to power a motor in response to an increase in fuel cost
relative to electricity cost.
11. The method of claim 6, further comprising: increasing a battery
state of charge threshold below which engine power is used to
charge the traction battery.
12. The method of claim 6, further comprising: raising a battery
state of charge threshold above which traction battery power is
requested to power a motor in response to a decrease in fuel cost
relative to electricity cost.
13. A plug-in hybrid electric vehicle control method, comprising:
receiving electricity cost and fuel cost by a vehicle controller;
and delaying one of a traction battery charging request and a
traction battery discharging request in response to the received
electricity cost and fuel cost.
14. The method of claim 13, wherein delaying a traction battery
charging request comprises reducing a battery state of charge
threshold below which engine power is requested to charge the
traction battery in response to an increase in fuel cost relative
to electricity cost.
15. The method of claim 13, wherein delaying a fraction battery
charging request comprises increasing a battery state of charge
threshold below which engine power is requested to charge the
fraction battery in response to a decrease in fuel costs relative
to electricity price.
16. The method of claim 13 wherein receiving electricity cost and
fuel cost comprises periodically receiving the electricity cost and
the fuel cost from a wireless network.
17. The method of claim 13 further comprising displaying a driver
interface that prompts for entry of the electricity cost and the
fuel cost.
18. The method of claim 13 wherein the electricity cost and the
fuel cost change in response to vehicle location while charging the
traction battery.
19. The method of claim 13 further comprising delaying the fraction
battery charging request by increasing a battery state of charge
threshold below which engine power is requested to charge the
fraction battery in response to vehicle location.
20. A plug-in hybrid electric vehicle, comprising: a battery; an
engine; an electric motor electrically connected to the battery; a
memory to store a battery charge set point, fuel cost, and
electricity cost; and a controller to control operation of the
engine and the electric motor based on the fuel cost and
electricity cost, wherein the controller modifies the battery
charge set point based at least partially on location of the
vehicle.
21. The vehicle of claim 20, wherein the controller modifies the
battery charge set point based at least partially on fuel cost for
the engine, at least partially on electricity costs or both.
Description
TECHNICAL FIELD
[0001] This disclosure relates to systems and methods for
controlling operation of plug-in electric vehicles based on cost
associated with at least two different power sources.
BACKGROUND
[0002] Plug-in hybrid electric vehicles (PHEVs) include a traction
battery to store electric power used by a traction motor to propel
the vehicle. The electric power may be provided by an external
power source, such as the power grid, or an on-board power source,
such as a fuel cell or internal combustion engine. In some vehicle
architectures, the on-board power source may provide torque to the
vehicle wheels alone or in combination with the traction motor,
while in other architectures the on-board power source is only used
to provide electric power to the battery and/or traction motor. The
vehicle operating strategy that determine whether to power the
vehicle using the traction battery, second power source, or both,
is typically determined by the manufacturer during design and
development to achieve desired fuel economy, vehicle performance,
and maintain the traction battery within desired operating
parameters, for example. While drivers may be provided the option
to operate in an electric only, engine only, or various types of
hybrid operating modes, these modes are generally designed to
achieve the best fuel economy within the constraints imposed by the
selected operating mode.
SUMMARY
[0003] A vehicle, systems, and methods for controlling a plug-in
hybrid electric vehicle provide greater use of a fuel burning
engine when the cost of fuel is low relative to the cost of
electricity. If the cost of electricity is relatively low compared
to the cost of fuel, then the use of plug-in charging can be
increased.
[0004] A plug-in hybrid electric vehicle can include a traction
battery, an engine (e.g., internal combustion engine), and an
electric motor. The battery can be charged by the motor or by a
plug-in to an electrical source. The vehicle can also include a
memory to store a battery charge point at which the internal
combustion engine provides motive force to generate electricity to
charge the traction battery. The vehicle can also include a
controller to modify the battery charge point in response to
arbitration criteria to control battery charging from the engine.
In an example, the arbitration criteria can be based at least
partially on fuel cost for the engine. In an example, the
arbitration criteria can be based at least partially on electricity
costs. In an example, the arbitration criteria include location of
the vehicle. In an example, the controller can alter a deadband of
neither charging the battery with the internal combustion engine
nor drawing power from the battery and can alter this deadband
using the arbitration criteria.
[0005] A hybrid electric vehicle control method can include storing
a battery charge point at which an engine begins charging a
traction battery and outputting the battery charge point, in
response to an arbitration of a price of fuel versus cost of
electricity, to control traction battery charging from the engine.
In an example, the modifying step can include using at least one of
a fuel cost and an electricity price as the arbitration criteria.
In an example, the modifying step includes using location of the
vehicle as an input to the arbitration criteria.
[0006] A hybrid electric vehicle control method can include
operating an engine at a first traction battery charge point
associated with at least one of fuel cost and electricity cost and
operating the engine at a second traction battery charge point
different from the first traction battery charge point in response
to a change in at least one of the fuel cost and the electricity
cost. In an example, the control method can include receiving at
least one of the fuel cost and the electricity cost from a wireless
network.
[0007] In an example, the control method can include modifying at
least one of the first traction battery charge point and the second
traction battery charge point in response to location of the
vehicle.
[0008] In an example, the control method can include reducing a
battery state of charge threshold below which engine power is used
to charge the traction battery.
[0009] In an example, the control method can include raising a
battery state of charge threshold above which traction battery
power is requested to power the motor in response to an increase in
fuel cost relative to electricity cost.
[0010] In an example, the control method can include increasing a
battery state of charge threshold below which engine power is used
to charge the traction battery.
[0011] In an example, the control method can include raising a
battery state of charge threshold above which traction battery
power is requested to power the motor in response to a decrease in
fuel cost relative to electricity cost.
[0012] A hybrid electric vehicle control method can include
receiving electricity cost and fuel cost by a vehicle controller
and delaying one of a traction battery charging request and a
traction battery discharging request in response to the received
electricity cost and fuel cost.
[0013] In an example, delaying a traction battery charging request
can include reducing a battery state of charge threshold below
which engine power is requested to charge the traction battery in
response to an increase in fuel cost relative to electricity
cost.
[0014] In an example, delaying a traction battery charging request
can include increasing a battery state of charge threshold below
which engine power is requested to charge the traction battery in
response to a decrease in fuel costs relative to electricity
price.
[0015] In an example, receiving electricity cost and fuel cost can
include periodically receiving the electricity cost and the fuel
cost from a wireless network.
[0016] In an example, the control method can include displaying a
driver interface that prompts for entry of the electricity cost and
the fuel cost.
[0017] In an example, the electricity cost and the fuel cost
changes in response to vehicle location while charging the traction
battery.
[0018] In an example, the control method can include delaying the
traction battery charging request by increasing a battery state of
charge threshold below which engine power is requested to charge
the traction battery in response to vehicle location.
[0019] It will be appreciated that any of the above methods may be
performed by the vehicle described herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is an example hybrid-electric vehicle with a battery
pack.
[0021] FIG. 2 is a battery pack arrangement comprised of battery
cells and battery cell monitoring and controlling systems.
[0022] FIG. 3 is a schematic view of a hybrid electric vehicle in
an example.
[0023] FIG. 4 is a graph depicting operation of a system or method
for an example hybrid electric vehicle.
[0024] FIG. 5 shows an operation graph for an example hybrid
electric vehicle.
[0025] FIG. 6 shows an operation graph for an example hybrid
electric vehicle.
[0026] FIG. 7 shows operation of a system or method for controlling
a hybrid electric vehicle.
DETAILED DESCRIPTION
[0027] Embodiments of the present disclosure are described herein.
It is to be understood, however, that the disclosed embodiments are
merely examples and other embodiments can take various and
alternative forms. The figures are not necessarily to scale; some
features could be exaggerated or minimized to show details of
particular components. Therefore, specific structural and
functional details disclosed herein are not to be interpreted as
limiting, but merely as a representative basis for teaching one
skilled in the art to variously employ the present invention. As
those of ordinary skill in the art will understand, various
features illustrated and described with reference to any one of the
figures can be combined with features illustrated in one or more
other figures to produce embodiments that are not explicitly
illustrated or described. The combinations of features illustrated
provide representative embodiments for typical applications.
Various combinations and modifications of the features consistent
with the teachings of this disclosure, however, could be desired
for particular applications or implementations.
[0028] Fluctuations in energy prices are posing a variety of
challenges to automotive customers with respect to purchasing and
operating plug-in hybrid electric vehicles (PHEVs). During periods
of higher gas prices, customers tend to favor more fuel efficient
vehicles including PHEVs over larger and less efficient vehicles.
However, in areas where electricity prices are comparatively
higher, the cost of operating PHEVs can increase operating costs
and reduce cost-savings. PHEV strategies that control under what
operating conditions the engine or power source other than the
traction battery is used are determined by the manufacturer during
development and testing to meet various goals such as fuel
efficiency, vehicle performance, and battery requirements, for
example. These strategies typically do not consider operating costs
associated with the different energy sources, such as electricity
and gasoline, for example. The present disclosure describes systems
and methods to cost efficiently use a plug-in hybrid electric
vehicle, or any other vehicle having two on-board energy or fuel
sources, by controlling operation of the vehicle based on the cost
of the associated energy/fuel source.
[0029] The operating costs of a PHEV can be affected by adjusting
the engine based battery power request in response to changes in
prices of electricity and fuel, e.g., gasoline, diesel, natural gas
propane, kerosene, bio-diesel, etc. The method described herein
focuses on reducing the cost by increasing the amount of energy
drawn from an external electrical source, e.g., the power grid
using plug-in charger, during periods when the electrical energy is
less expensive than fuel and increasing the amount of energy from
the engine to propel the vehicle and/or to charge the battery when
cost of electricity is higher than the cost of fuel.
[0030] FIG. 1 depicts an example of a hybrid-electric vehicle 102,
e.g., plug-in hybrid-electric vehicle. A plug-in hybrid-electric
vehicle 102 may comprise one or more electric motors 104
mechanically connected to a hybrid transmission 106. In addition,
the hybrid transmission 106 is mechanically connected to an engine
108. Engine 108 may be an internal combustion engine that consumes
a combustible fuel, e.g., gasoline, diesel, kerosene, natural gas,
propane etc. The hybrid transmission 106 may also be mechanically
connected to a drive shaft 110 that is mechanically connected to
the wheels 112. The electric motors 104 can provide torque to the
wheels when the engine 108 is turned on. The electric motors 104
consume electrical energy to provide torque to propel the vehicle
102. The electric motors 104 can provide deceleration capability
when the engine 108 is turned off. The electric motors 104 may be
configured as generators and can provide fuel economy benefits by
recovering energy that would normally be lost as heat in the
friction braking system. The electric motors 104 may also reduce
pollutant emissions since the hybrid electric vehicle 102 may be
operated in electric mode under certain conditions.
[0031] The traction battery or battery pack 114 stores energy that
can be used by the electric motors 104. A vehicle battery pack 114
typically provides a high voltage DC output. The traction battery
typically operates at over 100 volts which is an increased voltage
in comparison to a conventional vehicle battery nominal voltage of
12-24 volts. Although not expressly defined in the National
Electrical Code.RTM., low voltage generally refers to less than 60
volts Direct Current (DC) and 30 volts Alternating Current (AC)
calculated by root mean square (RMS), while voltages above this
threshold are generally considered high voltage, although this
convention may vary by geographic region or application. The
traction battery also has greater current capacity in comparison to
a conventional vehicle battery. This increased voltage and current
is used by electric motor(s) 104 to convert the electrical energy
stored in the battery to mechanical energy in the form of a torque
which is used to provide vehicle propulsion.
[0032] The battery pack 114 is electrically connected to a power
electronics module 116. The power electronics module 116 is also
electrically connected to the electric motors 104 and provides the
ability to bi-directionally transfer energy between the battery
pack 114 and the electric motors 104. For example, a typical
battery pack 14 may provide a DC voltage while the electric motors
104 may require a three-phase AC current to function. The power
electronics module 116 may convert the DC voltage to a three-phase
AC current as required by the electric motors 104. In a
regenerative mode, the power electronics module 116 will convert
the three-phase AC current from the electric motors 104 acting as
generators to the DC voltage required by the battery pack 114. The
methods described herein are equally applicable to a pure electric
vehicle or any other device using a battery pack.
[0033] In addition to providing energy for propulsion, the battery
pack 114 may provide energy for other vehicle electrical systems. A
typical system may include a DC/DC converter module 118 that
converts the high voltage DC output of the battery pack 114 to a
low voltage DC supply that is compatible with other vehicle loads.
Other high voltage loads, such as compressors and electric heaters,
may be connected directly to the high-voltage bus from the battery
pack 114. In a typical vehicle, the low voltage systems are
electrically connected to a 12V battery 120. An all-electric
vehicle may have a similar architecture but without the engine
108.
[0034] The battery pack 114 may be recharged by an external power
source 126, e.g., the electrical power grid 127 at a rate that can
be charged per kilowatt hour of power supplied to the battery 114
of the vehicle 102. The battery charge storage status can be
measured as a state of charge (SOC). The external power source 126
may provide AC or DC power to the vehicle 102 by electrically
connecting through a charge port 124. The charge port 124 may be
any type of port configured to transfer power from the external
power source 126 to the vehicle 102. The charge port 124 may be
electrically connected to a power conversion module 122. The power
conversion module may condition the power from the external power
source 126 to provide the proper voltage and current levels to the
battery pack 114. In some applications, the external power source
126 may be configured to provide the proper voltage and current
levels to the battery pack 114 and the power conversion module 122
may not be necessary. The functions of the power conversion module
122 may reside in the external power source 126 in some
applications. The vehicle engine, transmission, electric motors,
battery, power conversion and power electronics may be controlled
by a powertrain control module (PCM) 128.
[0035] In addition to illustrating a plug-in hybrid vehicle, FIG. 1
can illustrate a battery electric vehicle (BEV) if engine 108 is
removed. Likewise, FIG. 1 can illustrate a traditional hybrid
electric vehicle (HEV) or a power-split hybrid electric vehicle if
components 122, 124, and 126 are removed. FIG. 1 also illustrates
the high voltage system which includes the electric motor(s), the
power electronics module 116, the DC/DC converter module 118, the
power conversion module 122, and the battery pack 114. The high
voltage system and battery pack includes high voltage components
including bus bars, connectors, high voltage wires, circuit
interrupt devices,
[0036] The individual battery cells within a battery pack may be
constructed from a variety of chemical formulations. Typical
battery pack chemistries may include but are not limited to lead
acid, nickel cadmium (NiCd), nickel-metal hydride (NIMH),
Lithium-Ion or Lithium-Ion polymer. FIG. 2 shows a typical battery
pack 200 in a simple series configuration of N battery cell modules
202. The battery cell modules 202 may contain a single battery cell
or multiple battery cells electrically connected in parallel. The
battery pack, however, may be composed of any number of individual
battery cells and battery cell modules connected in series or
parallel or some combination thereof. A typical system may have one
or more controllers, such as a Battery Control Module (BCM) 208
that monitors and controls the performance of the battery pack 200.
The BCM 208 may monitor several battery pack level characteristics
such as pack current measured by a current sensor 206, pack voltage
210 and pack temperature 212. A current sensor may utilize a
variety of methods based on physical principles to detect the
current including a Hall effect IC sensor, a transformer or current
clamp, a resistor in which the voltage is directly proportional to
the current through it, fiber optics using an interferometer to
measure the phase change in the light produced by a magnetic field,
or a Rogowski coil, for example. In the event a battery cell is
charging or discharging such that the current entering or exiting
the battery cell exceeds a threshold, the battery control module
may disconnect the battery cell via the use of a circuit interrupt
device (CID) such as a fuse or circuit breaker.
[0037] In addition to the pack level characteristics, there may be
battery cell level characteristics that are measured and monitored.
For example, the terminal voltage, current, and temperature of each
cell may be measured. A system may use a sensor module 204 to
measure the characteristics of one or more battery cell modules
202. The characteristics may include battery cell voltage,
temperature, age, number of charge/discharge cycles, etc.
Typically, a sensor module will measure battery cell voltage.
Battery cell voltage may be voltage of a single battery or of a
group of batteries electrically connected in parallel or in series.
The battery pack 200 may utilize up to Nc sensor modules 204 to
measure the characteristics of all the battery cells 202. Each
sensor module 204 may transfer the measurements to the BCM 208 for
further processing and coordination. The sensor module 204 may
transfer signals in analog or digital form to the BCM 208. The
battery pack 200 may also contain a battery distribution module
(BDM) 214 which controls the flow of current into and out of the
battery pack 200.
[0038] FIG. 3 is a schematic view of hybrid electric vehicle 102
that can include modules, which can include processing circuitry to
execute instructions and methods steps and memory devices, also
referred to as non-transitory computer readable storage media, to
store data and/or instructions. Some or all of the operations set
forth in the figures may be contained as a utility, program,
subprogram, or other software, in any desired computer readable
storage medium. In addition, the operations may be embodied by
computer programs, which can exist in a variety of forms both
active and inactive. For example, they may exist as software
program(s) comprised of program instructions in source code, object
code, executable code or other formats. Exemplary computer readable
storage media include conventional computer system RAM, ROM, EPROM,
EEPROM, and magnetic or optical disks or tapes. It is therefore to
be understood that any electronic device capable of executing the
above-described functions or modules may perform those functions,
including dedicated electronic circuits, circuitry, integrated
circuits or chips, etc. Once the circuitry stores or is loaded with
the instructions the circuitry becomes a dedicated machine to
execute the instructions. The various modules may be connected or
functions may be performed in an order or sequence other than
illustrated depending upon the particular application and
implementation. Similarly, one or more functions or modules may be
repeated and/or omitted under particular operating conditions or in
particular applications, although not explicitly illustrated.
[0039] In one embodiment, the modules illustrated are primarily
implemented by software, instructions, or code stored in a computer
readable storage device or memory and executed by circuitry, one or
more microprocessor-based computers or controllers to control
operation of the vehicle based on cost of available energy sources.
In one embodiment, an energy price module 301 receives energy price
information from an external network. In another embodiment, energy
price information is provided by a user via the driver interface.
The energy price information includes the prices of one or more
energy sources available for use in the particular application. In
the representative embodiment illustrated, the energy price
information includes the prices of fuel for the internal combustion
engine and the price of electricity. This price information can be
supplied or updated periodically, and the time period may be
selected or specified by the user in some embodiments, e.g.,
hourly, daily, weekly, monthly, etc. The energy price information
can be downloaded from the internet or other database. The
information can also be loaded into a mobile communication device,
such as a cellular telephone, and then input into the vehicle,
either electronically or manually by the user via the driver
interface. In another example, the energy price database is stored
in an electronic system outside the vehicle.
[0040] A controller 305, which may be implemented in software
and/or hardware as previously described, receives the energy price
information and a user input to activate the controller 305 to
determine power set points. The controller 305 operates to
arbitrate selection and control of one or more vehicle energy
sources based on the costs of fuel and the cost of electricity from
the external source. The controller 305, using computing circuitry
and memory circuitry, determines whether to supply more electrical
energy from the internal combustion engine by operating the motor
as a generator and charging the battery and/or providing electrical
current direction to the traction motor to propel the vehicle when
the price of fuel is relatively lower than the price of electricity
from the external source. The fuel price can be a gallon or liter
of gas, either at retail price, a discount price, a wholesale price
or other pricing structure. The price of electricity can be the
retail electrical grid price of a kilowatt-hour of electricity. Of
course, energy cost information may be specified in a variety of
formats or units and may be converted to various other equivalent
formats or units depending on the particular application or
implementation. For example, energy cost information may be
automatically obtained during based on a location provided by a
satellite navigation system, e.g., GPS, or cellular signal and
associated cost information during refueling or recharging. Energy
cost information may be provided or specified based on recognition
of location, or information exchanged with a charging station, for
example. Other types of electrical sources can include rates at
electrical charging stations and/or work places, which may be
specified by kilowatt-hour, or by minutes or hours charging or
connected to a charging station, for example. Controller 305 sets
or customizes the energy-based battery power request curve 307
based on the controller's arbitrated determination or relative cost
differential between the fuel cost and the electrical energy cost.
The controller 305 can set the curve 307 at any time electrical
energy is needed to charge the battery or when there are price
changes in the fuel cost or electricity cost, for example. From the
curve 307 and the controller 305, the battery discharge limit is
sent to the battery power arbitration module 309.
[0041] The vehicle inputs module 303 receives various inputs from
the user and sensors in the vehicle. Example inputs include
accelerator pedal input, which can represent a user's power
request, and brake pedal input, which can represent a stop or speed
reduction request by the user. Vehicle inputs module 303 may
interface with or be integrated with vehicle telematics and receive
data or signals from onboard sensors or downloaded from external
sources. Other driver interface inputs are also possible. Examples
include vehicle performance preferences, electrical motor usage,
battery settings, trip information, etc. The gear selection or
automatic transmission positions (PRNDL) may also be provided as
vehicle inputs to module 303. The inputs to module 303 can be
selectively sent to the controller 305, the battery power
arbitration module 309 and the hybrid electric vehicle blending and
optimization module 311. The driver interface may include one or
more types of input and/or output devices such as a touch screen
with programmable inputs, switches, buttons, knobs, etc. to
manually enter energy price information and/or control various
types of user settings that affect control of the engine and or
motors based on energy costs.
[0042] The battery power arbitration module 309 also receives the
external temperature as an input along with the vehicle inputs from
module 303 and the battery discharge limits from the set curve 307.
The battery power arbitration module 309 determines the desired
battery power using its inputs. The desired battery power is output
to the blending and optimization module 311. It will be recognized
that the battery power arbitration module 309 and HEV blending and
optimization module 311 can be part of the power electronics module
116. The HEV blending and optimization module 311 can send signals
to the electric motor 104 and the engine 108 to control operation
of both.
[0043] FIG. 4 is a graph of electrical power requested curve 307
from the engine to provide electrical power from on-board power
sources within the vehicle. The graph has an X-axis of state of
charge (SOC) and a Y-axis of requested battery power. In an
example, the engine drives a motor to produce electrical energy for
storage in the battery or for supplying current directly to another
motor to propel the vehicle at certain set points on the curve 307.
The curve 307 is a linear function as shown with a plurality of set
points, here, four distinct set points 411, 412, 413, and 414.
There is a deadband where no energy is requested from the battery
between the zero power lower saturation limit set point 411 and the
zero power upper saturation limit set point 412. The band between
the zero power lower saturation limit (ZPLSL) set point 411 and the
battery power lower saturation limit (BPLSL) set point 413 has the
battery 114 being charged by the engine 108, e.g., a charging
request. In this example, the battery power lower saturation limit
(BPLSL) range begins at set point 414 and extends to a SOC of zero.
This is the lowest power that can be requested by the vehicle
control system and it has a lower SOC relative to the battery power
request slope between the set points 411 and 413. In this example,
the battery power upper saturation limit begins at set point 414.
This is the peak power that can be requested by the vehicle control
system and it requires a higher SOC relative to the battery power
request slope between the set points 412 and 414. In an example,
the set point 411 can be set at 30% SOC and zero power. In an
example, the set point 412 can be set at 70% SOC and zero power. In
an example, the set point 413 can be set at 10% SOC and negative 10
kWatts. In an example, the set point 414 can be set at 80% SOC and
positive 10 kWatts power.
[0044] FIG. 5 is a graph of electrical power curve 307' from the
engine to provide electrical power within the vehicle that differs
from the FIG. 4 example in that there is a difference in fuel
pricing and/or electricity pricing. In the representative example
illustrated in FIG. 5, the price of fuel has increased relative to
the price of fuel from FIG. 4. As a result, the system as described
herein changes the battery power request curve or function as
implemented in the present modules. The zero power lower saturation
limit set point 511 and the zero power upper saturation limit set
point 512 are changed from the default zero power lower saturation
limit set point 411 and the default zero power upper saturation
limit set point 412. In this example, the deadband at the zero
power request is increased in length. In an example, the zero power
lower saturation limit set point 511 is set at 15% SOC, i.e., lower
than the FIG. 4 setpoint 411, e.g., a 30% SOC. In an example, the
zero power lower saturation limit set point can be reduced by half
when the price of fuel increases. In an example, the zero power
upper saturation limit set point 512 is set at 85% SOC, i.e.,
higher than the FIG. 4 setpoint 412, e.g., a 70% SOC. In an
example, the zero power upper saturation limit (ZPUSL) set point
can be increased by a rate of about 20% to from 70% SOC to 85% SOC
when the price of fuel increases. In an example, the setpoints 513
and 514 can remain the same as setpoints 413 and 414. The battery
power lower set limit (BPLSL) set point 513 can be decreased on the
X-axis to a less than 10% SOC but the maximum charging power that
can be requested from the engine to the battery will remain the
same. The slope of the power request function from 512 to 514 can
remain the same as the slope of the power request function shown
between setpoints 412 to 414 (FIG. 4). The battery power upper
saturation limit (BPUSL) set point 514 can be increased on the
X-axis to a 90% SOC but the maximum power that can be requested
from the battery will remain the same. The slope of the charge
request function from 511 to 513 can remain the same as the slope
of the charge request function shown between setpoints 411 to 413
(FIG. 4). The fuel price increase can be relative to the price of
electricity or an absolute change in the price of fuel on its
own.
[0045] FIG. 6 is a graph of an electrical power curve 307'' from
the engine to provide electrical power within the vehicle that
differs from the examples of FIGS. 4 and 5 in that there is a
further difference in fuel pricing and/or electricity pricing. In
the representative example illustrated in FIG. 6, the price of fuel
has decreased relative to both of the above examples of FIGS. 4 and
5. As a result, the system as described herein changes the battery
power request curve or function as implemented in the present
modules to use more fuel to charge the battery and power the
vehicle. In this example, the deadband is decreased relative to the
above two examples. The zero power lower saturation limit set point
611 and the zero power upper saturation limit set point 612 are
increased and decreased, respectively. This will increase the
engine based battery power for both charging the battery and power
the electric motor. In an example, zero power lower saturation
limit set point 611 is set at 45% SOC. In an example, zero power
upper saturation limit set point 612 is set at 55% SOC. As a result
the no power requested from the internal combustion engine state,
e.g., the deadband, is only in the range of 45% SOC and 55% SOC.
That is, the deadband range is one seventh the deadband range of
the FIG. 5 example. This curve 307'' can also change the setpoints
613 and 614. The battery power lower set limit set point 613 can be
decreased on the X-axis to a less than 10% SOC but the maximum
charging power that can be requested from the engine to the battery
will remain the same. In an example, the set point 613 is set at
42.5% SOC. The slope of the power request function from 512 to 514
can remain the same as the slope of the power request function
shown between setpoints 412 to 414 (FIG. 4) or can have a greater
slope. The battery power upper saturation limit set point 614 can
be decreased on the X-axis to a 57.5% SOC but the maximum power
that can be requested from the battery will remain the same. The
slope of the charge request function from 511 to 513 can remain the
same as the slope of the charge request function shown between
setpoints 411 to 413 (FIG. 4) or can be greater. The fuel price
increase can be relative to the price of electricity or an absolute
change in the price of fuel on its own.
[0046] The above examples show fixed points of engine electricity
demand for either powering the vehicle or charging the battery. It
is within the scope of the present disclosure to allow the set
points to be adjustable to readjust the deadband. The user of the
vehicle can adjust the use of the engine for generation of
electricity. In an example, the user can select that the vehicle
use the engine to generate more electricity regardless of price,
e.g., out of environmental concerns or based on location of the
vehicle, for example.
[0047] FIG. 7 is a flowchart of a method 700 for controlling
vehicle operation based on energy costs of a vehicle having two or
more energy sources, such as a plug-in hybrid electric vehicle
having fuel for an engine and electric power for a traction motor,
with electric power provided from the engine, or from an external
battery charging source. At 701, the modules (circuitry,
electronics, software, etc.) of the vehicle store the default
electrical power request that defines the engine's contribution to
the electrical load of the vehicle. In an example, the engine's
electrical power request in its default settings can be represented
by the graph shown in FIG. 4. At 702, the energy-cost based control
is started. The user can select this feature, e.g., at an interface
on the vehicle or elected at an external device that communicates
with the vehicle, e.g., a computer, mobile phone, tablet, or other
communication device.
[0048] At 703, the energy cost for one or more energy sources is
received. The vehicle can receive the energy or fuel cost from the
operator via a vehicle or driver interface, or electrically or
wirelessly from a network. In another example, the fuel costs are
received at a computing device remote from the vehicle and
transferred by the computing device to a receiver within the
vehicle using a wired and/or wireless connection. At 704, the
electricity costs are received. The electricity costs can be
received directly by the vehicle from a wired or wireless network
such as the internet using WiFi, Bluetooth, CDMA, or similar
communication protocol, via a charging cord connected to a charging
station, or from a user via a driver interface or a remote
computing device, such as a cell phone, for example. In another
example, the electricity costs are received by a computing device
remote from the vehicle. The costs can also be associated with a
particular geographic region or location, such as the home and work
locations of the user of the vehicle. The costs can also be related
to the location of the vehicle itself during charging of the
battery from an external source. At 705, the cost changes are
calculated. The current fuel cost and electricity cost are compared
to one or more historical costs, which can be stored in memory
located on the vehicle or in a computing device. The fuel cost and
electricity costs can be compared to each other to elect to use
more of the lower cost energy source.
[0049] At 706, it is determined whether there is an increase in
fuel cost. If yes, then the vehicle may decrease the use of the
fuel consuming engine in favor of electrical energy provided by the
external power source and regenerative braking that is stored in
the battery. In an example, the engine provided electrical power
function is altered, e.g., from either the FIG. 4 graph 307 to the
FIG. 6 graph 307'' or the FIG. 5 graph 307' to either the FIG. 4
graph 307 or the FIG. 6 graph 307'' to reduce the use of fuel to
provide electrical power to charge the battery or propel the
vehicle, e.g., the SOCs at which the engine is triggered to produce
electricity and/or propel the vehicle are expanded and the deadband
increases. The process flow then can return to step 703. If at 706,
fuel cost or electrical cost does not increase, then at 708 it is
determined whether fuel cost or electrical cost decreases. If no,
then the process returns to step 703. If fuel costs have decreased,
then at 709 the use of fuel to provide electrical energy in the
vehicle, and specifically to the battery, is increased. In an
example, the engine provided electrical power function is altered,
e.g., from either the FIG. 6 graph 307'' to either of the FIG. 4
graph 307 or the FIG. 5 graph 307' to increase the use of fuel to
provide electrical power to charge the battery, e.g., the SOCs at
which the engine is triggered to produce electric are decreased and
the deadband decreases.
[0050] While the method 700 shows a strategy focused on fuel costs,
a similar type of process can be used for electricity costs. The
cost of electricity is received. If the cost of electricity drops,
then the use of electricity from an external source is increased.
If the cost of electricity rises, then the use of fuel can be
increased. The cost of fuel and the cost of electricity are
arbitration criteria used by processes, systems, modules and
devices to determine whether to increase the use of fuel, decrease
the use of fuel, increase the use of external electricity or
decrease the use of external electricity.
[0051] Certain systems, apparatus, applications or processes are
described herein as including a number of modules or mechanisms. A
module or a mechanism may be a unit of distinct functionality that
can provide information to, and receive information from, other
modules. Accordingly, the described modules may be regarded as
being communicatively coupled. Modules may also initiate
communication with input or output devices, and can operate on a
resource (e.g., a collection of information). The modules may be
implemented as hardware circuitry, optical components, single or
multi-processor circuits, memory circuits, software program modules
and objects, firmware, and combinations thereof, as appropriate for
particular implementations of various embodiments.
[0052] The processes, methods, or algorithms disclosed herein can
be deliverable to/implemented by a processing device, controller,
or computer, which can include any existing programmable electronic
control unit or dedicated electronic control unit. Similarly, the
processes, methods, or algorithms can be stored as data and
instructions executable by a controller or computer in many forms
including, but not limited to, information permanently stored on
non-writable storage media such as ROM devices and information
alterably stored on writeable storage media such as floppy disks,
magnetic data tape storage, optical data tape storage, CDs, RAM
devices, FLASH devices, MRAM devices and other magnetic and optical
media. The processes, methods, or algorithms can also be
implemented in a software executable object. Alternatively, the
processes, methods, or algorithms can be embodied in whole or in
part using suitable hardware components, such as Application
Specific Integrated Circuits (ASICs), Field-Programmable Gate
Arrays (FPGAs), state machines, controllers, or any other hardware
components or devices, or a combination of hardware, software and
firmware components.
[0053] Although exemplary embodiments are described above, it is
not intended that these embodiments describe all possible forms
encompassed by the claims. The words used in the specification are
words of description rather than limitation, and it is understood
that various changes can be made without departing from the spirit
and scope of the disclosure. As previously described, the features
of various embodiments can be combined to form further embodiments
of the invention that may not be explicitly described or
illustrated.
[0054] Although various embodiments may have been described as
providing advantages or being preferred over other embodiments or
prior art implementations with respect to one or more desired
characteristics, those of ordinary skill in the art recognize that
one or more features or characteristics can be compromised to
achieve desired overall system attributes, which depend on the
specific application and implementation. These attributes can
include, but are not limited to cost, strength, durability, life
cycle cost, marketability, appearance, packaging, size,
serviceability, weight, manufacturability, ease of assembly, etc.
As such, embodiments described as less desirable than other
embodiments or prior art implementations with respect to one or
more characteristics are not outside the scope of the disclosure
and can be desirable for particular applications.
* * * * *