U.S. patent application number 11/467038 was filed with the patent office on 2007-11-29 for locomotive and rail car braking regeneration and propulsion system and method.
Invention is credited to Thomas Lee Bartley, Paul Everett Kaufman.
Application Number | 20070272116 11/467038 |
Document ID | / |
Family ID | 38748322 |
Filed Date | 2007-11-29 |
United States Patent
Application |
20070272116 |
Kind Code |
A1 |
Bartley; Thomas Lee ; et
al. |
November 29, 2007 |
LOCOMOTIVE AND RAIL CAR BRAKING REGENERATION AND PROPULSION SYSTEM
AND METHOD
Abstract
A method of using one or more electric locomotive and energy
storage car combinations to assist a train consist up an uphill
climb, the one or more electric locomotive and energy storage car
combinations each having one or more diesel electric locomotives
and one or more separate energy storage cars, including adding the
one or more electric locomotive and energy storage car combinations
to the train consist prior to an uphill climb; using the one or
more electric locomotive and energy storage car combinations to
assist the train consist up the uphill climb; and removing the one
or more electric locomotive and energy storage car combinations
from the train consist after the uphill climb. The one or more
electric locomotive and energy storage car combinations are added
to a train consist traveling downhill to assist with the downhill
slowing through dynamic braking regeneration that is used to
recharge the energy storage of the one or more separate energy
storage cars.
Inventors: |
Bartley; Thomas Lee; (San
Diego, CA) ; Kaufman; Paul Everett; (Bernardsville,
NJ) |
Correspondence
Address: |
PROCOPIO, CORY, HARGREAVES & SAVITCH LLP
530 B STREET, SUITE 2100
SAN DIEGO
CA
92101
US
|
Family ID: |
38748322 |
Appl. No.: |
11/467038 |
Filed: |
August 24, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11420064 |
May 24, 2006 |
|
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11467038 |
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Current U.S.
Class: |
105/35 ;
903/903 |
Current CPC
Class: |
B60T 13/662 20130101;
Y02T 10/7005 20130101; Y02T 30/00 20130101; B60L 7/22 20130101;
B60T 1/10 20130101; B61C 7/04 20130101; Y02T 30/16 20130101; B60L
2200/26 20130101; Y02T 10/70 20130101; B60L 50/51 20190201 |
Class at
Publication: |
105/35 ;
903/903 |
International
Class: |
B61C 7/04 20060101
B61C007/04 |
Claims
1. A method of using one or more electric locomotive and energy
storage car combinations to assist a train consist up an uphill
climb, the one or more electric locomotive and energy storage car
combinations each having one or more diesel electric locomotives
and one or more separate energy storage cars, comprising: adding
the one or more electric locomotive and energy storage car
combinations to the train consist prior to an uphill climb; using
the one or more electric locomotive and energy storage car
combinations to assist the train consist up the uphill climb;
removing the one or more electric locomotive and energy storage car
combinations from the train consist after the uphill climb.
2. The method of claim 1, further including running the one or more
electric locomotive and energy storage car combinations downhill,
and using braking regeneration to charge the one or more separate
energy storage cars of the one or more electric locomotive and
energy storage car combinations.
3. The method of claim 2, wherein the one or more electric
locomotive and energy storage car combinations are added to the
train consist at a first switch yard to assist the train consist
uphill, the one or more electric locomotive and energy storage car
combinations are removed from the train consist at a second switch
yard.
4. The method of claim 3, wherein the second switch yard is a
summit location.
5. The method of claim 3, wherein the second switch yard is a
downhill location.
6. The method of claim 5, wherein the one or more electric
locomotive and energy storage car combinations are reversed in
direction at the second switch yard, and are added to a train
consist heading uphill at the second switch yard to assist the
train consist uphill.
7. The method of claim 1, wherein the one or more diesel electric
locomotives are one or more dual mode diesel electric
locomotives.
8. The method of claim 1, wherein the one or more diesel electric
locomotives are one or more hybrid-electric diesel electric
locomotive.
9. The method of claim 1, wherein the one or more separate energy
storage cars are one or more electric commuter rail cars configured
to haul one or more large energy storage packs.
10. The method of claim 1, wherein the one or more separate energy
storage cars are one or more converted double deck commuter rail
cars with one or more energy storage packs mounted therein to
provide a low center of gravity.
11. The method of claim 1, wherein the one or more separate energy
storage cars are at least one of one or more flat rail cars and one
or more specialty built rail car chassis with a energy storage pack
mounted thereon.
12. A method of using one or more energy storage cars to assist a
train consist up an uphill climb, the consist having one or more
electrically propelled locomotives for primary propulsion power,
comprising: adding the one or more energy storage cars to the train
consist prior to an uphill climb; using the one or more energy
storage cars to supply additional power to the one or more dual
mode locomotives to assist the train consist up the uphill climb;
removing the one or more energy storage cars from the train consist
after the uphill climb.
13. The method of claim 12, further including running the one or
more energy storage cars downhill, and using braking regeneration
to charge the one or more separate energy storage cars from the
motor/generators of the dual mode locomotives or other rail
cars.
14. The method of claim 13, wherein the one or more energy storage
cars are added to the train consist at a first switch yard to
assist the train consist uphill, the one or more energy storage
cars are removed from the train consist at a second switch
yard.
15. The method of claim 14, wherein the second switch yard is a
summit location.
16. The method of claim 14, wherein the second switch yard is a
downhill location.
17. The method of claim 6, wherein the one or more energy storage
cars are reversed in direction at the second switch yard, and are
added to a train consist heading uphill at the second switch yard
to assist the train consist uphill.
18. The method of claim 12, wherein the one or more electrically
propelled locomotives are one or more dual mode diesel electric
locomotives.
19. The method of claim 12, wherein the one or more electrically
propelled locomotives are one or more hybrid-electric diesel
electric locomotive.
20. The method of claim 12, wherein the one or more separate energy
storage cars are one or more electric commuter rail cars configured
to haul one or more large energy storage packs.
21. The method of claim 12, wherein the one or more separate energy
storage cars are one or more converted double deck commuter rail
cars with one or more energy storage packs mounted therein to
provide a low center of gravity.
22. The method of claim 12, wherein the one or more separate energy
storage cars are at least one of one or more flat rail cars and one
or more specialty built rail car chassis with a energy storage pack
mounted thereon.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation-in-part application of
U.S. patent application Ser. No. 11/420,064, filed May 24, 2006.
This application claims the benefit of this prior application and
this prior application is incorporated by reference herein as
though set forth in full.
FIELD OF THE INVENTION
[0002] The field of the invention relates to locomotive assists to
assist the propulsion of freight trains up long grades.
BACKGROUND OF INVENTION
[0003] Railroad operations often use one or more additional diesel
locomotives to assist the propulsion of freight trains up long
grades. At the top of the grades the locomotives are uncoupled from
the train at a switch yard or siding and sent back to the bottom of
the grade to assist additional trains requiring assistance up the
long grades.
[0004] A problem with these diesel locomotives used to assist the
propulsion of freight trains up long grades is that the diesel
locomotives consume a lot of diesel fuel and pollute the
environment during this frequently repeated process.
SUMMARY OF THE INVENTION
[0005] Accordingly, an aspect of the invention involves recycling
freight train braking energy from downhill grades to use as an
assist to the propulsion of freight trains traveling uphill. Rather
than using one or more diesel locomotives to assist moving the
train uphill, the method of this invention uses one or more
electric powered locomotives with one or more attached energy
storage car(s) to provide the electric power. The energy storage
car(s) contain electrical energy storage, e. g., a battery pack,
which is charged by the electric motor/generators of the locomotive
from a previous descent of the grade. At the top of the grade the
additional electric locomotives with attached energy storage car(s)
are coupled to a descending train to provide dynamic braking and
charge the energy storage device.
[0006] Another aspect of the invention involves a method of using
one or more electric locomotive and energy storage car combinations
to assist a train consist up an uphill climb. The one or more
electric locomotive and energy storage car combinations each have
one or more diesel electric locomotives and one or more separate
energy storage cars. The method includes adding the one or more
electric locomotive and energy storage car combinations to the
train consist prior to an uphill climb; using the one or more
electric locomotive and energy storage car combinations to assist
the train consist up the uphill climb; and removing the one or more
electric locomotive and energy storage car combinations from the
train consist after the uphill climb.
[0007] A further aspect of the invention involves a method of using
one or more energy storage cars to assist a train consist up an
uphill climb, the consist having one or more electrically propelled
locomotives for primary propulsion power. The method includes
adding the one or more energy storage cars to the train consist
prior to an uphill climb; using the one or more energy storage cars
to supply additional power to the one or more dual mode locomotives
to assist the train consist up the uphill climb; and removing the
one or more energy storage cars from the train consist after the
uphill climb.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The accompanying drawings, which are incorporated in and
form a part of this specification, illustrate embodiments of the
invention and together with the description, serve to explain the
principles of this invention.
[0009] FIG. 1 is a block diagram depicting an embodiment of an
axle-mounted braking regeneration system for a passive rail
car.
[0010] FIG. 2 is a block diagram depicting an embodiment of the
axle-mounted braking regeneration system on a multi-axle passive
rail car.
[0011] FIG. 3 is a graph of speed versus time for a diesel consist
with a braking regeneration, energy storage, and acceleration
system that runs at a continuous power level of 300 kW and consumes
8.4 kWh of energy, and a diesel consist without a braking
regeneration energy storage and acceleration system.
[0012] FIG. 4 is another graph of speed versus time for a diesel
consist with a braking regeneration, energy storage, and
acceleration system that runs at a continuous power level of 133 kW
and consumes 4.8 kWh of energy, and a diesel consist without a
braking regeneration energy storage and acceleration system.
[0013] FIG. 5 is a block diagram of an embodiment of a train
consist with multiple electric locomotive and battery car
combinations.
[0014] FIG. 6A is a diagram of an embodiment of multiple unit
electric commuter rail cars configured to haul large battery packs
rather than passengers.
[0015] FIG. 6B is a diagram of an embodiment of a modified
converted double deck commuter rail car with a battery pack mounted
in the rail car to provide a low center of gravity.
[0016] FIG. 6C is a diagram of an embodiment of a flat rail car or
specialty built rail car chassis with a battery pack mounted
thereon.
[0017] FIG. 7A is a block diagram depicting an embodiment of a dual
mode locomotive configured to accept electric power from an
external battery car.
[0018] FIG. 7B is a block diagram depicting an embodiment of a
hybrid-electric locomotive configured to accept power from an
external battery car.
[0019] FIG. 8 is a graph of an exemplary rail road elevation grade
profile with a summit pass.
[0020] FIG. 9 is a block diagram illustrating an exemplary computer
system that may be used in connection with the various embodiments
described herein.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
[0021] With reference to FIGS. 1 and 2, an axle-mounted braking
regeneration energy storage and acceleration system 100 for a
passive rail car 110 will be described. As used herein, "passive
rail car" refers to rail car primarily propelled (e.g., pulled,
pushed) by a separate driving rail car (e.g., locomotive). A
passive rail car has no primary power unit for the conversion of
chemical fuel into electric or kinetic energy used to propel the
vehicle. A rail car is defined as a flange wheeled vehicle where
the wheels roll on and are guided by rails on a road bed also known
as a railroad track. Although the braking regeneration system 100
will be described as being axle-mounted, in alternative
embodiments, the braking regeneration system 100 is mounted to
other and/or additional structures of a passive rail car.
[0022] In the embodiment shown, the passive rail car 110 is a Comet
V commuter rail car including multiple axles 120 with wheels 130 on
opposite ends of the axles 120 and a friction braking system
attached to multiple axles. The axles 120 rotate with rotation of
the wheels 130. In the embodiment shown in FIG. 2, each rail car
includes two trucks 135. Each truck 135 carries two axles 120. The
drive and braking regeneration system 100 is repeated for each rail
car truck 135. Although the braking regeneration system 100 will be
described as being used with a commuter rail car, in alternative
embodiments, the braking regeneration system 100 is applied to
other passive rail cars other than a commuter rail car such as, but
not by way of limitation, flat car, tank car, box car, bulk
material car, fuel car, container car, and caboose. Further,
although the braking regeneration system 100 will be described at
times as being used with a single passive individual rail car 110,
in alternative embodiments, the axle-mounted braking regeneration
system 100 is applied to an entire train of (or linked series of)
passive rail cars often referred to as a "consist".
[0023] The braking regeneration system 100 may include a gear box
140 and a motor/generator 150 for each axle 120, a single
dual-inverter/controller 160 per truck 135 (per two axles 120), a
single energy storage 170 per rail car 110, a single auxiliary
power inverter 180 per rail car, a single set of braking resistors
190 per truck, and a single control computer 200 per rail car 110.
In alternative embodiments, one or more of the number of trucks,
axles, passive rail cars, braking regeneration systems, components
of the braking regeneration system, and/or other elements described
herein may vary from that shown and described herein. For example,
but not by way of limitation, in an alternative embodiment, the
braking regeneration system 100 includes one larger generator/motor
incorporated on one axle 120 per rail car 110 instead of four
smaller gearbox/motor/generator systems, one on each axle 120 of
the rail car 110.
[0024] The gear box 140 is mechanically connected to the axle 120.
The gear box 140 transfers torque between the axle 120 and the
motor/generator 150. At the same time as the gear box 140 provides
a speed reduction to match the motor rpm to the axle shaft rpm, the
torque increases by the same ratio as the speed reduction. In
another alternative embodiment any required rpm speed reduction
occurs in the motor connection to the axle 120 and a separate gear
box 140 is not required. In yet other alternative embodiments the
gear box 140 may include a clutch, multiple gears and a
transmission. The single dual-inverter 160 controls both axle drive
motor/generators 150 on the truck 135 and performs the power flow
switching for the operation of the energy storage 170 and the
braking resistors 210. The motor/generator 150 along with the
dual-inverter 160 can be Siemens ELFA components that are used on
electric and hybrid-electric heavy-duty vehicles or other
manufacturer's components used on electrically propelled trains.
The motor/generator 150 generates energy during braking
regeneration and powers the wheels 130 via the gear box 140 and
axle 120 during an acceleration mode. In the embodiment shown, the
motor/generator 150 is a combined, integrated motor and generator;
however, in an alternative embodiment, motor/generator 150 includes
physically separated motor and generator. The energy storage 170
includes a central energy storage system, which provides the energy
storage for the energy needs of the whole rail car 110. In
alternative embodiments, one or more other types of energy storage
systems are used such as, but not limited to, one or more or a
combination of different battery chemistries, ultracapacitors,
flywheels, or springs. A single inverter and power conditioning
module 180 provides for the power needs 210 (e.g., rail car
emergency power, rail car accessory power, cooling pumps 220) on
the rail car 110. A typical commuter rail car accessory power draw
may include lighting, heating, ventilation, air conditioning
(HVAC), and plug-in power for electronic devices. The inverter and
power conditioning module 180 may replace all or part of the power
normally supplied by the head-end power (HEP) from the train
locomotive.
[0025] The motor/generator 150, the dual-inverter 100, the energy
storage 170, the auxiliary power inverter 180, and the braking
resistors 190 may be liquid cooled. The liquid cooling loop, not
shown, consists of liquid coolant, typically 50/50 water/ethylene
glycol, a heat exchanger radiator with electric fans, and coolant
pumps 220 to circulate the coolant. One or more coolant loops may
be used on the rail car to manage the temperature of the electric
power components 150, 160, the energy storage 170, the power
conditioning module 180, and the HVAC system.
[0026] One of the cooling loops may include the braking resistors
190 that may serve two different functions. The braking resistors
190 are high power electrical resistors that dissipate power by
heating a circulating fluid. The coolant heat may be dissipated in
one or more of a heat exchanging radiator that radiates heat to the
air passing through the heat exchanger, a heat exchanging radiator
to heat passenger compartment air, a coolant loop through the
energy storage to warm the energy storage 170, and any other
component on the rail car that would benefit from receiving
additional heat from the coolant or heated air from a heat
exchanger. When the motor/generator 150 is generating more power
than can be stored in the energy storage 170 and used by the
auxiliary power 180, the inverter controller 160 can switch the
excess power to the braking resistors to heat the circulating
coolant. This may occur when the braking regeneration
electromagnetic braking is used rather than add wear to the normal
friction brakes. The braking resistors 190 may also be heated by
the energy storage 170 and used to supply heat via the circulating
fluid to a heat exchanger radiator for heating the passenger
compartment of the commuter rail car.
[0027] The control computer 200 controls operation of the braking
regeneration system 100 in the manner described herein. The braking
regeneration systems 100 are controlled by the control computer 200
to initiate the acceleration and deceleration modes without
lurching the rail cars 100 and compressing the couplers. Real time
onboard sensors along with train communications provide input that
is processed by processor(s) of the control computer 200 using the
computer control algorithms related to applying power or drag to
the consist.
[0028] The braking regeneration system 100 will now be described
during deceleration and acceleration of the consist.
[0029] On deceleration, the generator 150 puts a drag on the axle
120 to slow down the rail car 110. System controls prevent the rail
cars 110 from abruptly compressing and extending the couplers. The
individual rail cars 110 have their systems activated in an in-line
or series configuration, one at a time, to prevent lurching. The
independent control system may be transparent to the remainder of
the consist or may operate as an integrated control system with
other cars of the consist. Below a minimum speed, for example 3
mph, the braking regeneration system is turned off and the standard
friction brake system is applied to stop the train.
[0030] The energy captured from deceleration would, in turn, be fed
through the inverter/controllers 160 and into the nickel metal
hydride (NiMH) battery energy storage system 170. The charge and
discharge levels of the nickel metal hydride (NiMH) battery energy
storage system 170 may be limited to extend the cycle life of the
energy storage system 170. Ultracapacitors lack sufficient energy
storage for this application. However, in an embodiment of the
invention, an ultracapacitor pack is incorporated with the battery
pack to protect and extend the life of the battery pack. Other
types of energy storage, either singly or in combinations, can
replace or be added to batteries and/or ultracapacitors.
[0031] On acceleration, the recycled stored energy is consumed as
the motor/generators 150 are then configured as electric motors 150
to help the locomotive accelerate the consist. As an example of
high power operation, the electric motor/generators 150 operate at
least 60 seconds at a 282 kW power level before exhausting the
scheduled amount of stored energy. A lower power level for a longer
period of time during acceleration puts less stress on the
components resulting in lower maintenance costs, increased system
life, and improved reliability. The energy management system is
designed to have infinite variability of control parameters to
provide for optimization of the energy capture and recycle. The
power is applied until the approximate 4.8 kWh (on average for this
embodiment) are delivered for acceleration.
[0032] The performance curves in FIGS. 3 and 4 show the
acceleration improvement that can be obtained by using the recycled
braking regeneration energy from each rail car 110 to assist the
diesel locomotive. Higher top speeds can be achieved and, thus,
regenerate more braking energy.
[0033] The performance is provided by a simulation of a PL42 diesel
locomotive with a six car Comet V consist. It is based on test
track performance for a 0% grade. The 0% grade assumption is
representative of an elevation energy neutral model for two way
travel over the route.
[0034] FIG. 3 graphically shows the acceleration and braking
performance for an average 2.6 mile distance between stations. The
acceleration curve A for the braking regeneration system 100 is
calculated at a continuous power level of 300 kW. As shown by the
curves A, B, a diesel consist with the braking regeneration system
100 accelerates faster and has a greater average speed than a
diesel consist without the braking regeneration system 100. The
performance curve A for the diesel consist with braking
regeneration propulsion shows that the consist can achieve 60 mph
in 60 seconds time and can reach maximum track speed inside of 100
seconds. The standard diesel consist (curve B) requires 105 seconds
to reach 60 mph and cannot reach maximum track speed in 2.6 miles.
This benefit is created by having the braking regeneration system
100 powering a total of 24 driven axles along with the locomotive
versus four for just the locomotive. However, this performance uses
8.4 kWh of energy, more than is available from the average recycled
braking regeneration. In the embodiment shown, the braking
regeneration system 100 assists the rail car 110 in acceleration,
but does not provide all required power to accelerate the rail car
110 to top speed. In an alternative embodiment, the braking
regeneration system 100 provides all required power to accelerate
the rail car 110 (or passive rail car) to top speed.
[0035] The graph shown in FIG. 4 is for a more efficient and
practical configuration that consumes 4.8 kWh, the same amount of
energy as is available from the average recycled braking
regeneration event. In this example, the consist can achieve 60 mph
in 75 seconds while operating at a continuous power level of 133
kW. This remains a very impressive acceleration curve for a diesel
hauled 6-car consist that can achieve a maximum track speed of 80
mph in 130 seconds in a 2.6 mile average distance between
stations.
[0036] These two graphs demonstrate the unique benefit of the
braking regeneration system 100 and the almost infinite flexibility
available to optimize energy capture. The backup emergency energy
remains available at all times in spite of the energy consumed by
acceleration. In addition, the anticipated battery life, due to a
reduction in system stress, is increased.
[0037] One of the advantages of the braking regeneration system 100
is that it allows the elimination of the emergency power battery
system on the rail car along with the battery charger. The braking
regeneration system 100 is located under floor, so eliminating the
existing emergency power battery system frees up space for the
components of the braking regeneration system 100, which may be
retrofitted onto existing commuter rail cars 110 (and/or passive
rail cars) and/or implemented into the original manufacture of the
rail car (and/or passive rail cars) and/or rail car chassis/trucks.
The energy storage 170 is managed to guarantee at least two hours
of emergency backup energy at any time to comply with the Federal
Railway Administration (FRA) regulations. This is done by
establishing a depletion point of the energy storage system 170 at
a level that insures that the energy storage system 170 will always
be able to operate. Present rail cars are marginal or non compliant
for providing two hours of emergency backup power when the rail car
is just going into revenue service after sitting for a day. The
capacity of the energy storage system 170 eliminates any concern
about meeting the emergency backup power requirement.
[0038] With the amount of onboard energy storage, the braking
regeneration system 100 will start up automatically from an
overnight layover. Should the energy drop to a minimum threshold,
three ways to start up the braking regeneration system 100 include:
1) pull or push the rail car 110 to turn the axles 120 and
generators 150, 2) use a Head-end Power (HEP) connection to provide
electric power from the auxiliary engine generator in the
locomotive, and 3) use a grid-based charger.
[0039] The first method is preferred and self managed. At start up,
the generators 150 operate while the locomotive is pulling or
pushing the rail car 110. The generators 150 place an extra drag on
the locomotive but would only be active until the energy storage
system 170 was at an operating level ready to accept the first
deceleration energy capture. Normally, the first train deceleration
would bring the energy storage system 170 to an operating capacity
level, preparing it for the next acceleration event. Each
deceleration event adds to the energy storage 170 state of charge
(SOC) to achieve a full working level.
[0040] If desired, the other two methods are available for
emergency backup. An HEP approach is similar to the current
practice: start up the HEP and let it charge the system. A grid
based charger could be used to connect the energy storage system
170 to a wayside power supply.
[0041] By way of example but not limitation of other types of
passive rail cars, another advantage of implementation of the
braking regeneration system 100 on a Comet V commuter rail car is
an estimated fuel savings of $22,500 annually and in excess of
$675,000 over the 30-year life of the rail car. This is based on
the following assumptions: one 125,000 pound rail car generates 4.7
kWh of energy savings per deceleration act from an average speed of
70 mph; assuming that the rail car is in service 320 days out of
the year and makes four revenue service trips per day (two AM peak
and two PM peak) plus weekend service and holiday service, there
are 25,600 energy reclamation opportunities (320 days at four
passenger trips a day equates to 1280 trips a year of local service
stopping 20 times); 25,600 opportunities at 4.7 kWh per stop per
car results in a total recoupable energy level of 120,320 kWh,
annual fuel savings would be approximately 9,000 gallons of diesel
fuel based on an energy efficiency of 30%; at $2.50 per gallon for
diesel fuel, fuel savings would total $22,500 annually and in
excess of $675,000 over the 30-year life of the rail car. Since
fuel costs generally rise over time, future savings are expected to
be even greater than $22,500 annually. An additional benefit
associated with the reduction in fuel use would be the reduction in
exhaust emissions that the combustion of that fuel would have
generated.
[0042] Also, by way of example but not limitation of other types of
passive rail cars, additional advantages of implementation of the
braking regeneration system 100 on a Comet V commuter car include
benefits to the subsystems on the rail car. For example, because
the recovered energy has been taken away from the generation of
heat and wear in the brake system, the brake wear and corresponding
maintenance for the brake system is reduced. The rail car
decelerates by capturing energy on deceleration, while reducing the
burden on the braking system. In hybrid-electric buses that use
brake regeneration, brake maintenance intervals have been at least
doubled. Therefore, a conservative estimate is that a 50% savings
would be realized on the maintenance of the rail car brake system.
This would double the current reline interval of the rail car 110
along with the subsequent labor and materials required to perform
the reline.
[0043] The emergency power system would be the next area of
savings. By way of example but not limitation of other types of
passive rail cars, the Comet V commuter rail car currently has a 74
volt DC emergency power system and battery charger on board each
commuter rail car. Other rail cars may operate their emergency
power system at other voltages. This method of generating and
storing energy for an emergency application period of up to 2 hours
could be completely eliminated from the rail car and would then be
incorporated into the energy storage system 170 and the auxiliary
power inverter and conditioning module 180. The functions of the
battery charger and the battery system are now assumed by the main
energy storage 170 and can easily provide the emergency
requirements. One clear benefit to this approach would be that the
system 100 would be able to easily provide more than the two hours
of required run time for the emergency backup at any point in
time.
[0044] A more advanced potential for savings is the concept that
the system 100 could actually be configured to provide adequate
power so that each rail car 110 could provide energy for itself,
thus, reducing head-end power (HEP) requirements. Under this
concept, the braking regeneration energy storage system 100 could
provide power for all hotel loads on the rail car 110 including
HVAC, lighting and communications. Because the 50 kWh of battery
energy storage supplies power to the rail car 110 through the
inverter and power conditioning module 180, the HEP requirements
are significantly reduced or eliminated. If it is desired to
transfer power from the locomotive to the passenger rail car, it
can be done through the wheels 130 by using the braking generator
150. This approach would reduce the electrical load and extend the
life of the HEP system while saving HEP fuel and reducing diesel
engine emissions. Recent locomotive designs have completely
eliminated the use of an HEP engine-generator and, instead, operate
the HEP generator from a power take off of the main diesel engine
of the locomotive. In this type of system the braking regeneration
system eliminates the need for the additional generator and could
contribute to the reduction in total overall horsepower required of
the main diesel engine of the locomotive, thus, further reducing
fuel consumption and diesel exhaust emissions.
[0045] An alternative embodiment of a braking regeneration system
uses hydraulic components where a hydraulic motor/pump replaces the
electric motor/generator 150; a hydraulic valve controller replaces
the electric inverter switch controller 160; a hydraulic
accumulator replaces the energy storage 170; and a hydraulic
retarder replaces the braking resistors 190. The hydraulic retarder
requires some form of liquid or air heat exchanger to dissipate
energy. In its simplest form a hydraulic braking regeneration
system is the hydraulic analog of the electric braking regeneration
system and is a potentially lower cost alternative to an electric
braking regeneration system to save fuel costs. Such systems have
been built for medium duty hydraulic truck drive systems.
[0046] The amount of energy stored in an accumulator is a function
of the accumulator pressure and the volume of fluid stored in the
accumulator. The temperature of the system, the type of gas used to
pre-charge the system, and the initial pressure of the pre-charge
gas can impact the amount of energy stored at a given accumulator
pressure. The equation to calculate the energy stored in an
accumulator is:
E=(Pc*Vc-(P*Vc*((Pc/P) (1/k))))/(1-k)
[0047] Where: E is the energy stored in the accumulator. [0048] Pc
is the pre-charge pressure of the accumulator. [0049] Vc is the
volume of gas in the accumulator at pre-charge. [0050] P is the
current accumulator pressure. And [0051] k is ratio of specific
heats (Boltzmann constant) for the pre-charge gas. [0052] The value
of k for a gas varies with pressure at high pressures; [0053]
values of 1.3 to 1.8 may be used for typical gases and pressures.
The pre-charge gas, pre-charge pressure, and volume of gas in the
accumulator will not vary on a rail car over a route cycle. Thus,
the State Of Charge (SOC) of a hydraulic accumulator is a function
only of its pressure. Although the accumulator pressure will vary
with charge gas temperature, the SOC can be determined with
acceptable accuracy even if this term is ignored.
[0054] A hydraulic braking regeneration system is potentially less
expensive than an electric braking regeneration system, but,
depending on the practical limits of the size of the accumulator,
may have limited energy storage. In concept, a hydraulic motor
generator would replace the auxiliary power inverter 180 to power
the auxiliary emergency and accessory electrical loads 210.
[0055] With reference to FIG. 5, an embodiment of a train consist
250 with multiple electrically propelled locomotive (e.g. diesel
electric-powered locomotive) and battery car combinations 260 and
method of recovering and recycling braking energy of the consist
250 operating over a long grade with a significant elevation change
will be described. The train consist 250 is a long train of one or
more electrically propelled locomotives 270, battery cars 280, and
passive rail cars 290 (e.g., passive rail car(s) 110). Each
multiple electrically propelled locomotive and battery car
combination 260 includes at least one electrically propelled
locomotive 270 and at least one battery car 280. As an alternative
to putting all the energy storage on individual passive rail cars
as previously described, all the energy storage or additional
energy storage is put in a battery car 280 connected to the
electrically propelled locomotive 270.
[0056] Railroad operations often use one or more additional diesel
electric locomotives to assist the propulsion of freight trains up
long grades. At the top of or some point beyond the summit of the
grades the locomotives are uncoupled from the train at a switch
yard or siding and sent back to the bottom of the grade, where they
may be used again for the same purpose with the next freight train
requiring assistance.
[0057] With reference additionally to FIG. 8, in this aspect of the
invention, freight train braking energy from the downhill grade 310
is recycled to use as an assist in the propulsion of freight trains
traveling uphill 310. Similarly, freight train braking energy from
the downhill grade 300 past the summit 320 is recycled to use as an
assist in the propulsion of freight trains traveling uphill 300.
Rather than using one or more diesel electric-powered locomotives
to assist moving the train uphill, one or more diesel
electric-powered locomotives 270 (or other electric-powered
locomotive(s)) with attached energy storage car(s) 280 are used to
provide the electric power to assist moving the train uphill 310,
300. At an upper rail switch yard 305, one or more additional
diesel electric-powered locomotives 270 with attached energy
storage car(s) 280 are coupled to a descending train first
traveling uphill 300 to the summit 320 then traveling downhill 310
to provide dynamic braking and charge the energy storage of the
energy storage cars 280. The one or more additional diesel
electric-powered locomotives 270 with attached energy storage
car(s) 280 may be the same or different than the one or more
additional diesel electric-powered locomotives 270 with attached
energy storage car(s) 280 that assisted in moving an ascending
train uphill. Although the external battery car(s) 280 have been
described as obtaining energy from braking regeneration by the
diesel electric locomotive during travel downhill 310, 300,
additionally or alternatively, the external battery car(s) 280
obtain energy from braking regeneration by one or more passive rail
cars 110 as described above with respect to FIGS. 1-4. Additionally
or alternatively, one or more passive rail cars 110 such as those
described above with respect to FIGS. 1-4 are used to assist moving
the train (e.g., uphill, on level ground, etc.).
[0058] The battery cars 280 and associated electric locomotives 270
of the combinations 260 are strategically placed at railroad grades
where they ascend and descend continually with the passing railroad
traffic. Additionally or alternatively, only the battery cars 280
are strategically placed at railroad grades where they ascend and
descend continually with passing railroad traffic hauled by a
diesel electric-powered locomotive that has been configured to
accept energy from an energy storage car.
[0059] With reference to FIGS. 6A-6C, a number of different
embodiments of energy storage cars 280A, 280B, 280C will be
described. The energy storage cars 280A, 280B, 280C contain
electrical energy storage 330, e. g., a battery pack, which is
charged by electric motor(s)/generator(s) of the locomotive 270
(and/or from electric motor(s)/generator(s) of other rail cars)
from a previous descent of the grade.
[0060] With reference to FIG. 6A, an embodiment of multiple unit
electric commuter rail cars 280A configured to haul large battery
packs 330 rather than passengers is shown. The HVAC (heating,
ventilation, and air conditioning) environmental control system
originally installed in the commuter rail car for passenger comfort
may be retained for the battery pack operation. The electric
commuter rail cars 280A are configured to operate in pairs to share
subsystems, but each car includes its own motor(s)/generator(s) for
propulsion and dynamic braking regeneration that can charge and
accept energy from the battery pack in place of, or in addition to,
an electrically propelled locomotive.
[0061] With reference to FIG. 6B, an embodiment of a modified
converted double deck commuter rail car 280B with a battery pack
330 mounted in the rail car 280B to provide a low center of gravity
is shown. Similar to commuter rail car 280A, the HVAC environmental
control system originally installed in the commuter rail car for
passenger comfort may be retained for the battery pack
operation.
[0062] With reference to FIG. 6C, an embodiment of a flat rail car
280C or specialty built rail car chassis 280C with a battery pack
330 mounted thereon is shown. The battery pack 330 may include an
enclosed shelter and battery mounting structure, and HVAC
environmental control system for the battery pack.
[0063] With reference to FIGS. 7A and 7B, a number of different
embodiments of diesel electric locomotives 270A, 270B will be
described. The locomotives 270A, 270B include one or more electric
motors 340 coupled to an axle 350 for driving the locomotive drive
wheels 360. One or more diesel engine(s) 370 power one or more
generator(s) 380 that supply electric power for powering the
electric motor 340. Although not shown, the locomotives 270 include
an onboard diesel fuel tank for supplying fuel to the diesel engine
370.
[0064] With reference to FIG. 7A, an embodiment of a dual mode
locomotive 270A configured as a multi mode locomotive to accept
electric power from the external battery car 280 is shown. The dual
mode locomotive 270A uses either diesel electric or all electric
power to power the electric motor(s) 340 to turn the drive wheels
250 in pushing and pulling operations. The multi mode locomotive
270A is a modified dual mode locomotive configured to combine
diesel electric with battery electric power to power the electric
motors(s) 340 to turn the drive wheels 250 in pulling and pushing
operations. Through braking regeneration, the motor(s)/generator(s)
340 of the locomotive 270A charge the energy storage(s) 330 of the
external battery car(s) 280. This way, freight train braking energy
from downhill grades is recycled to use as an assist to the
propulsion of freight trains traveling uphill. In another
embodiment the multi mode locomotive 270A or the hybrid locomotive
270B is configured to allow the diesel engine-generator to charge
the batteries in the energy storage car (and/or the on-board energy
storage 390) for special operations such as low noise travel with
the engine idling or turned off.
[0065] With reference to FIG. 7B, an embodiment of a
hybrid-electric locomotive 270B configured to accept power from an
external battery car 280 is shown. The hybrid-electric locomotive
270B includes on-board energy storage 390 (e.g., batteries) that
are charged by the generator 380 for supplying power to the
motor(s) 340 to turn the axle 350 and the drive wheels 360 in
pushing and pulling operations. Similar to the locomotive 270A,
through braking regeneration, the motor(s)/generator(s) 340 of the
locomotive 270B charge the energy storage(s) 330 of the external
battery car(s) 280 (and/or the on-board energy storage 390). This
way, freight train braking energy from downhill grades is recycled
to use as an assist to the propulsion of freight trains traveling
uphill.
[0066] GG and GK, "Green Goat," hybrid-electric rail yard switching
locomotives have been built by RailPower Technologies Corporation.
These "switchers" have up to 840 kWh of energy storage on-board
with maintenance free lead-acid batteries in addition to a 200 to
500 KW diesel generator set. The weight is about 275,000 pounds
with an equivalent 2000 horsepower. The inventors have determined
that these hybrid locomotives could be used/modified in accordance
with the principles of the invention described herein to perform a
grade "assist" function.
[0067] The following are some sample calculations by the inventors
in determining potential energy savings with the present
invention.
[0068] Equating energy saved to diesel fuel gallons and fuel costs
follows below: [0069] 1 gallon diesel=130,000 Btu [0070] 1 kWh=3414
Btu [0071] 1 gallon diesel=38.1 kWh [0072] Energy conversion
efficiency of diesel electric locomotive=26% [0073] 1 gallon
diesel=10 kWh recycled energy [0074] 1 MWh recycled energy=100
gallons diesel fuel saved
[0075] Li ion battery energy storage parameters: [0076] From A123
Corporation data sheets: [0077] 10-15 year calendar life [0078]
3000-7000 life cycles at 100% DoD (Depth of Discharge) [0079] 220
Wh/liter (6.2 kWh/cu. ft.) [0080] 110 Wh/kg (50 Wh/lb) [0081] From
Report ANL/ESD-42, "Costs of Lithium-ion Batteries for Vehicles,"
by Linda Gaines and Roy Cuenca, Center for Transportation Research,
Energy Systems Division, Argonne National Laboratory, 9700 South
Cass Avenue, Argonne, Ill. 60439, US Department of Energy, May
2000: [0082] Baseline Lithium-ion battery cost--$706/kWh [0083]
USABC Goal--$150/kWh (US Advanced Battery Consortium)
[0084] Recycling freight train braking energy from downhill grades
to use as an assist to the propulsion of freight trains traveling
uphill saves a considerable amount of energy compared to using one
or more additional diesel electric-powered locomotives to assist
the propulsion of freight trains up long grades. Rather than using
one or more diesel electric-powered locomotives to assist moving
the train uphill, the one or more multi mode diesel
electric-powered locomotives with one or more attached energy
storage cars assist moving the train uphill. The energy storage car
contains electrical energy storage, e. g., a battery pack, which is
charged by the electric motor/generators of the locomotive or other
cars from a previous descent of the grade. At the top of the grade
the additional electric locomotives with attached energy storage
cars are coupled to a descending train to provide dynamic braking
and charge the energy storage.
[0085] By way of example, but not limitation, one typical railroad
grade extends from San Bernardino, Calif. (elevation 1118 feet) up
the El Cajon Pass Summit (elevation 3855 feet), for an elevation
change of 2735 feet, and back down to the switch yard at Barstow,
Calif. (elevation 2163 feet). The 2735 foot elevation descent from
the summit to the switch yard at San Bernardino represents about
207 kWh of energy for a loaded freight car of 200,000 pounds.
1 foot-pound=3.766.times.10.sup.-7 kWh
200,000 pounds.times.2735 feet=206 kWh
Therefore, 20 rail cars descending the grade have about 4.1
megawatt hours (MWh) of energy. For a long consist of 100 rail cars
the energy is about 20.6 MWh not including the locomotives.
[0086] Assuming that 50% of the energy is recoverable from dynamic
braking regeneration capture and recycling, about 103 kWh of
useable energy storage is required per rail car. Operating at 50%
depth of discharge (DoD) to get 12,000 life cycles the energy
storage requirement is 206 kWh per 200,000 pound freight car. From
the Lithium-ion battery parameters the battery pack characteristics
are: [0087] Weight--4120 lbs [0088] Volume--33.2 cu. ft. [0089]
Baseline Cost--$145,436
[0090] Goal Cost--$30,900
[0091] At 80% battery efficiency each of the above cycles saves
81.6 kWh. At a diesel fuel cost of $3.00/gallon, the break even
point ($145,436/$3.00=48,479) is a fuel savings of 48,479 gallons
diesel or 485 MWh. At 81.6 kWh per cycle the break even point is
5944 battery energy storage cycles. This is well within the
expected 12,000 life cycles and suggests that another $148,000 of
diesel fuel savings (at $3.00/gallon) would accumulate before
battery replacement to help pay for the cost of installing the
batteries, motor/generators, and control equipment. With the
anticipated increasing future fuel prices and decreasing future
energy storage prices the projected savings increases beyond these
estimates. However, if the energy storage was placed on each
individual rail car, thereby adding significant weight to the rail
car, this savings is achieved only if the individual rail car
experiences thousands of life cycles within the 10 year calendar
life of the batteries.
[0092] The energy savings can be more cost effectively achieved
when the battery cars and associated electric locomotives (or the
battery cars only) are strategically placed at railroad grades
where they ascend and descend continually with the passing railroad
traffic. For the above El Cajon Summit example, one method is to
have an energy storage car for every 20 freight cars. The required
energy storage characteristics are 20 times those for a single car:
[0093] Energy Storage--2060 kWh [0094] Weight--82,400 lbs [0095]
Volume--664 cu. ft. [0096] Baseline Cost--$2.91 million [0097]
USABC Goal Cost--$618,000
[0098] Similar to the El Cajon Pass summit grade described above,
most grade applications will experience 11/2 to 2 cycles per round
trip because of the high point (summit) in the middle and lower
points at each of the rail switch yards. Therefore, estimating 1000
cycles per year, the fuel savings would pay for the batteries in
less than 6 years and at the end of 12 years (12,000 cycle life of
the batteries) there would be an extra fuel savings of $2.96
million that would have paid back more than the capital cost of
building the energy storage freight car. With the anticipated
increasing fuel costs and decreasing energy storage costs the extra
fuel savings will continue to increase. Extending this projection
from year 13 to end of year 36 (estimated rail car life) results in
an estimated $6 million diesel fuel cost savings ($250,000 per year
average over years 13 to 36) per energy storage rail car beyond the
capital costs and the energy storage costs. The estimated energy
savings is 1632 MWh per energy storage rail car per year, or
163,200 gallons of diesel fuel per energy storage rail car per
year.
[0099] For fewer charge/discharge cycles per year or for different
energy storage life characteristics, the size of the energy storage
can be decreased for a greater DoD such that the energy storage
cycle life and the energy storage calendar life match, thus saving
the overall energy storage costs while providing the required
energy storage. Alternatively, the energy storage can be sized for
a greater or lesser number of rail cars than the 20 rail cars
described in the example above.
[0100] FIG. 9 is a block diagram illustrating an exemplary computer
system 550 that may be used in connection with the various
embodiments described herein. For example, the computer system 550
(or various components or combinations of components of the
computer system 550) may be used in conjunction with the control
computers, controllers, or to control the functions described
herein. However, other computer systems and/or architectures may be
used, as will be clear to those skilled in the art.
[0101] The computer system 550 preferably includes one or more
processors, such as processor 552. Additional processors may be
provided, such as an auxiliary processor to manage input/output, an
auxiliary processor to perform floating point mathematical
operations, a special-purpose microprocessor having an architecture
suitable for fast execution of signal processing algorithms (e.g.,
digital signal processor), a slave processor subordinate to the
main processing system (e.g., back-end processor), an additional
microprocessor or controller for dual or multiple processor
systems, or a coprocessor. Such auxiliary processors may be
discrete processors or may be integrated with the processor
552.
[0102] The processor 552 is preferably connected to a communication
bus 554. The communication bus 554 may include a data channel for
facilitating information transfer between storage and other
peripheral components of the computer system 550. The communication
bus 554 further may provide a set of signals used for communication
with the processor 552, including a data bus, address bus, and
control bus (not shown). The communication bus 554 may comprise any
standard or non-standard bus architecture such as, for example, bus
architectures compliant with industry standard architecture
("ISA"), extended industry standard architecture ("EISA"), Micro
Channel Architecture ("MCA"), peripheral component interconnect
("PCI") local bus, or standards promulgated by the Institute of
Electrical and Electronics Engineers ("IEEE") including IEEE 488
general-purpose interface bus ("GPIB"), IEEE 696/S-100, and the
like.
[0103] Computer system 550 preferably includes a main memory 556
and may also include a secondary memory 558. The main memory 556
provides storage of instructions and data for programs executing on
the processor 552. The main memory 556 is typically
semiconductor-based memory such as dynamic random access memory
("DRAM") and/or static random access memory ("SRAM"). Other
semiconductor-based memory types include, for example, synchronous
dynamic random access memory ("SDRAM"), Rambus dynamic random
access memory ("RDRAM"), ferroelectric random access memory
("FRAM"), and the like, including read only memory ("ROM").
[0104] The secondary memory 558 may optionally include a hard disk
drive 560 and/or a removable storage drive 562, for example a
floppy disk drive, a magnetic tape drive, a compact disc ("CD")
drive, a digital versatile disc ("DVD") drive, etc. The removable
storage drive 562 reads from and/or writes to a removable storage
medium 564 in a well-known manner. Removable storage medium 564 may
be, for example, a floppy disk, magnetic tape, CD, DVD, etc.
[0105] The removable storage medium 564 is preferably a computer
readable medium having stored thereon computer executable code
(i.e., software) and/or data. The computer software or data stored
on the removable storage medium 564 is read into the computer
system 550 as electrical communication signals 578.
[0106] In alternative embodiments, secondary memory 558 may include
other similar means for allowing computer programs or other data or
instructions to be loaded into the computer system 550. Such means
may include, for example, an external storage medium 572 and an
interface 570. Examples of external storage medium 572 may include
an external hard disk drive or an external optical drive, or and
external magneto-optical drive.
[0107] Other examples of secondary memory 558 may include
semiconductor-based memory such as programmable read-only memory
("PROM"), erasable programmable read-only memory ("EPROM"),
electrically erasable read-only memory ("EEPROM"), or flash memory
(block oriented memory similar to EEPROM). Also included are any
other removable storage units 572 and interfaces 570, which allow
software and data to be transferred from the removable storage unit
572 to the computer system 550.
[0108] Computer system 550 may also include a communication
interface 574. The communication interface 574 allows software and
data to be transferred between computer system 550 and external
devices (e.g. printers), networks, or information sources. For
example, computer software or executable code may be transferred to
computer system 550 from a network server via communication
interface 574. Examples of communication interface 574 include a
modem, a network interface card ("NIC"), a communications port, a
PCMCIA slot and card, an infrared interface, and an IEEE 1394
fire-wire, just to name a few.
[0109] Communication interface 574 preferably implements industry
promulgated protocol standards, such as Ethernet IEEE 802
standards, Fiber Channel, digital subscriber line ("DSL"),
asynchronous digital subscriber line ("ADSL"), frame relay,
asynchronous transfer mode ("ATM"), integrated digital services
network ("ISDN"), personal communications services ("PCS"),
transmission control protocol/Internet protocol ("TCP/IP"), serial
line Internet protocol/point to point protocol ("SLIP/PPP"), and so
on, but may also implement customized or non-standard interface
protocols as well.
[0110] Software and data transferred via communication interface
574 are generally in the form of electrical communication signals
578. These signals 578 are preferably provided to communication
interface 574 via a communication channel 576. Communication
channel 576 carries signals 578 and can be implemented using a
variety of wired or wireless communication means including wire or
cable, fiber optics, conventional phone line, cellular phone link,
wireless data communication link, radio frequency (RF) link, or
infrared link, just to name a few.
[0111] Computer executable code (i.e., computer programs or
software) is stored in the main memory 556 and/or the secondary
memory 558. Computer programs can also be received via
communication interface 574 and stored in the main memory 556
and/or the secondary memory 558. Such computer programs, when
executed, enable the computer system 550 to perform the various
functions of the present invention as previously described.
[0112] In this description, the term "computer readable medium" is
used to refer to any media used to provide computer executable code
(e.g., software and computer programs) to the computer system 550.
Examples of these media include main memory 556, secondary memory
558 (including hard disk drive 560, removable storage medium 564,
and external storage medium 572), and any peripheral device
communicatively coupled with communication interface 574 (including
a network information server or other network device). These
computer readable mediums are means for providing executable code,
programming instructions, and software to the computer system
550.
[0113] In an embodiment that is implemented using software, the
software may be stored on a computer readable medium and loaded
into computer system 550 by way of removable storage drive 562,
interface 570, or communication interface 574. In such an
embodiment, the software is loaded into the computer system 550 in
the form of electrical communication signals 578. The software,
when executed by the processor 552, preferably causes the processor
552 to perform the inventive features and functions previously
described herein.
[0114] Various embodiments may also be implemented primarily in
hardware using, for example, components such as application
specific integrated circuits ("ASICs"), or field programmable gate
arrays ("FPGAs"). Implementation of a hardware state machine
capable of performing the functions described herein will also be
apparent to those skilled in the relevant art. Various embodiments
may also be implemented using a combination of both hardware and
software.
[0115] Furthermore, those of skill in the art will appreciate that
the various illustrative logical blocks, modules, circuits, and
method steps described in connection with the above described
figures and the embodiments disclosed herein can often be
implemented as electronic hardware, computer software, or
combinations of both. To clearly illustrate this interchangeability
of hardware and software, various illustrative components, blocks,
modules, circuits, and steps have been described above generally in
terms of their functionality. Whether such functionality is
implemented as hardware or software depends upon the particular
application and design constraints imposed on the overall system.
Skilled persons can implement the described functionality in
varying ways for each particular application, but such
implementation decisions should not be interpreted as causing a
departure from the scope of the invention. In addition, the
grouping of functions within a module, block, circuit or step is
for ease of description. Specific functions or steps can be moved
from one module, block or circuit to another without departing from
the invention.
[0116] Moreover, the various illustrative logical blocks, modules,
and methods described in connection with the embodiments disclosed
herein can be implemented or performed with a general purpose
processor, a digital signal processor ("DSP"), an ASIC, FPGA or
other programmable logic device, discrete gate or transistor logic,
discrete hardware components, or any combination thereof designed
to perform the functions described herein. A general-purpose
processor can be a microprocessor, but in the alternative, the
processor can be any processor, controller, microcontroller, or
state machine. A processor can also be implemented as a combination
of computing devices, for example, a combination of a DSP and a
microprocessor, a plurality of microprocessors, one or more
microprocessors in conjunction with a DSP core, or any other such
configuration.
[0117] Additionally, the steps of a method or algorithm described
in connection with the embodiments disclosed herein can be embodied
directly in hardware, in a software module executed by a processor,
or in a combination of the two. A software module can reside in RAM
memory, flash memory, ROM memory, EPROM memory, EEPROM memory,
registers, hard disk, a removable disk, a CD-ROM, or any other form
of storage medium including a network storage medium. An exemplary
storage medium can be coupled to the processor such the processor
can read information from, and write information to, the storage
medium. In the alternative, the storage medium can be integral to
the processor. The processor and the storage medium can also reside
in an ASIC.
[0118] The above description of the disclosed embodiments is
provided to enable any person skilled in the art to make or use the
invention. Various modifications to these embodiments will be
readily apparent to those skilled in the art, and the generic
principles described herein can be applied to other embodiments
without departing from the spirit or scope of the invention. Thus,
it is to be understood that the description and drawings presented
herein represent a presently preferred embodiment of the invention
and are therefore representative of the subject matter which is
broadly contemplated by the present invention. It is further
understood that the scope of the present invention fully
encompasses other embodiments that may become obvious to those
skilled in the art and that the scope of the present invention is
accordingly limited by nothing other than the appended claims.
* * * * *