Note: Descriptions are shown in the official language in which they were submitted.
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METHOD OF OPERATING VEHICLE AND ASSOCIATED SYSTEM
BACKGROUND
Technical Field.
The invention includes embodiments that relate to method of using the
propulsion
system. The invention includes embodiments that relate to a vehicle and
system.
Discussion of Art
Hybrid propulsion systems have been developed to recover some of the energy
that
would otherwise be wasted as heat during dynamic braking. The recovery of this
otherwise-wasted energy is regenerative braking. Hybrid propulsion systems can
use
two different energy sources: a heat engine and an energy storage unit. The
engine
may burn fuel to produce mechanical work - an internal combustion engine, a
turbine
engine, and a diesel engine are examples. The energy storage unit may include
an
electrically re-chargeable battery, an ultracapacitor, or a flywheel having a
high power
density.
The hybrid propulsion systems can act with regard to specific local events,
such as a
braking request or an accelleration request. The hybrid propulsion systems do
not
have a general awareness of the surrounding environment, and do not change
functionality based on that awareness. To the extent that any vehicle can
sense the
environment, one hybrid vehicle monitors ambient temperature and shuts down
battery use at ambient tempertures that would damage the batteries.
It may be desirable to have a propulsion system that implements a method of
operation that differs from those methods currently available. It may be
desirable to
have a propulsion system with properties and charecteristics that differ from
those
properties and characteristics of currently available propulsion systems.
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BRIEF DESCRIPTION
The invention includes embodiments that relate to method of operating a
vehicle
having an electric drive. The method includes defining a first zone and a
second zone.
The first zone has an associated first characteristic, and the second zone has
an
associated second characteristic that differs from the first characteristic.
The method
further includes switching an operating mode of a vehicle from a first
operating mode
in the first zone to a second operating mode in the second zone in response to
the
vehicle translating from the first zone to the second zone.
The invention includes embodiments that relate to an electrically drivable
vehicle.
The vehicle can include a controller capable of switching the operating mode
of the
vehicle from the first operating mode in the first zone to the second
operating mode in
the second zone in response to the vehicle translating from the first zone to
the second
zone. The first zone has the associated first characteristic and the second
zone has the
associated second characteristic that allows the zones to differs from each
other. The
vehicle further can include a sensor communicating with the controller that
can
determine if the vehicle translates to and from the second zone.
The invention includes embodiments that relate to a system having information
correlating an amount of electrical energy used by a vehicle to an amount of
fuel
consumed by the vehicle or an amount of emissions emitted by the vehicle. The
system includes a sensor and a controller. The sensor can measure the amount
of
energy supplied by the energy storage device and can communicate information
about
that energy amount to the controller. And, the controller can use the
correlation data
and the measured amount of the energy supplied by the energy storage device to
determine a saved amount of fuel or a reduced amount of emissions that would
have
otherwise occurred had the energy come from an engine rather than the energy
storage
device.
BRIEF DESCRIPTION OF DRAWINGS
Fig. 1 is a schematic block diagram of a method comprising an embodiment
according
to the invention.
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Fig. 2 is a schematic diagram illustrating a method comprising an embodiment
according to the invention.
DETAILED DESCRIPTION
The invention includes embodiments that relate to method of operating a
propulsion
system. The invention includes embodiments that relate to a vehicle having the
propulsion system. The invention includes embodiments that relate to the
vehicle
propulsion system. The ability to change operating modes depending on
geographic
locations may allow control of vehicle characteristics, such as emissions, and
may
allow vehicle operations liaving a reduced environmental impact in
environmentally
sensitive regions.
As used herein, voltage refers to direct current (DC) voltage unless context
or
language indicates otherwise. A prime mover includes an engine and an
electrical
generator, e.g. a diesel engine/alternator combination. Generally, an energy
battery
has a ratio that presents more energy than power, whereas a power battery has
a
greater power rating than energy rating.
With reference to Fig. 1, a method according to an embodiment of the invention
is
shown. The method includes defining zones of vehicle operation (block 100),
and
controlling the vehicle operating mode with regard to the zone in which the
vehicle is
located (block 110). Optionally, the method can include determining that a
zone
translation or change is upcoming, and switching the operating mode to prepare
for
the zone translation (block 120).
With regard to the zones, they include at least a first zone and a second
zone. The
first zone has an associated first characteristic and the second zone has an
associated
second characteristic that differs from the first characteristic. As used
herein, the first
zone is an area with relatively fewer restrictions on operating parameters,
and the
second zone is an area that has relative more concerns on operating parameters
than
the first zone. While the zone differences are discussed further hereinbelow,
a
mention here of one embodiment in which the first zone is relatively not
sensitive to
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emissions, and in which the second zone is an environmentally sensitive
region, may
help characterize the disclosure that follows.
The zones may have an interface or line separating them from each other, or
from an
inter-disposed zone (discussed later as a third zone). The first zone may be
distinguished from the second zone by a geo-fence. Other methods of defining
or
bounding the first zone include identifying a geographical area. The
geographical
limits may correspond to territorial rights, such as state lines, county
lines, country
borders, and the like. Also, the geographical limits may correspond to natural
terrain
features, such as rivers, hills, and the like. Yet other methods of bounding
the zones
include identification of certain features or characteristics that can be
associated with
a location. For example, the Los Angeles basin can be characterized as an
environmentally sensitive zone (first characteristic) that needs less
pollution and
fewer vehicle emissions. Another example is an area in which a tax scheme is
in
force (e.g., London, England) so that emissions are tracked and taxed within a
defined
municipality. The tax scheme, conversely, may supply a credit or benefit for
emissions reduction within a defined area (i.e., second zone).
The zones need not be static in some embodiments. If emissions are more
damaging
during a particular time of day, one may define a boundary of the first zone
dynamically with reference to a time of day. If noise is a concern in a noise-
sensitive
area, the zones may be differentiated by those areas where the noise is a
concern and
during those hours of the day in which the noise is concern.
The same may be done dynamically with reference to a day of a week. For
example, if
vehicle operations are to be near an area where particulate is a concern while
the local
population is exposed, then the zone may be defined to that area and during
those
days of concern. If, for example, a beach is fully occupied on a weekend, but
not on a
weekday, and particles are a concern when the beach is fully occupied, then
the zone
can be near the beach during the weekend.
With some planning, it is possible to identify yearly patterns, such as
national
holidays during which behavior is predictable. If so, then defining a boundary
of the
first zone dynamically with reference to a day of a year is possible.
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Because weather is closely monitored in most of the world, the weather,
climate or
environment may be an erivironmental indicator to define a zone. A method may
then
limit the first zone dynamically by reference to the environmental indicator
corresponding to the zone. For example, if an ozone alert is called for in an
area and
that alert is based on weather and climate conditions, that alert may serve as
an
environmental indicator - where, in one embodiment, an ozone-reduced operating
mode may be used as the second operating mode in the second zone. Other
suitable
environmental indicator may include an ultraviolet (UV) index, pollution
index,
ground level ozone content, ground level NOx content, ground level SOx
content,
carbon dioxide content, carbon monoxide content, wind speed, wind direction,
particulate matter content, or pollen count.
The first zone can be defined in absolute terms (e.g., a state line), or in
relative terms
compared to the second zone (e.g., a more restrictive tax scheme). For
example, the
first characteristic can be, relative to the second characteristic, a tax
benefit or a
reduction in one or more of tax liability based on one or more of emissions,
fuel
consumption, or noise; emissions; fuel consumption; or, noise. In an
alternative
embodiment, the first characteristic is a topologically-based ability to
regenerate an
energy storage device of the vehicle.
According to an embodiment of the invention, as the vehicle passes or
translates from
one zone to another zone, a controller on the vehicle recognizes that the
translation is
occurring (or about to occur) and controls the vehicle to switch an operating
mode of
a vehicle from a first operating mode in the first zone to a second operating
mode in
the second zone. In one aspect, the geo-fence or zone boundary is marked, and
the
operating mode switch is in response to the vehicle translating from the first
zone to
the second zone, or vice versa. Alternatively, a vehicle operator may engage a
manual
toggle to initiate the switch in one embodiment.
While operating in the first operating mode, the vehicle may be used in a
manner to
accomplish at least one of: an increase in battery life, an increase in
battery charge, an
increase in vehicle speed, or an increase in fuel economy according to one
embodiment. In another embodiment, the first operating mode may include
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optimizing vehicle perfortnance outside of the second zone so that upon
entering the
second zone at least one battery characteristic is in a determined state for
use in the
second zone. Such battery characteristics may include battery temperature or
the
battery state of charge. Particularly, the battery state of charge refers to
the useable
charge energy of the battery or bank of batteries. In another embodiment, the
vehicle
may operating in the first zone so that there is a reduction or elimination of
discharge
of an energy storage device coupled to electrical drive motors of the vehicle.
Thus,
the energy storage device devices (or batteries that are included therein) are
ready for
use upon translation into the second zone.
With reference to the second operating mode, the vehicle operates in a manner
to
accomplish at least one of: an increased tax benefit based on one or more of
reduced
emissions, reduced fuel consumption, or reduced noise; decreased emissions;
decreased fuel consumption; or, a decreased tax liability based on one or more
of
emissions, fuel consumption, or noise. Alternatively or additionally, the
vehicle in the
second mode of operation may operate so that the vehicle has decreased noise
from an
on-board engine. In one illustrative embodiment, the vehicle can top off the
charge
on an energy storage device having a bank of batteries in the first zone on
approach to
the second zone and use a diesel engine without regard to fuel efficiency, and
after
translating into the second zone the diesel engine is shut down or idled and
the vehicle
can be propelled by the energy storage device supplying electricity to
traction motors.
And, in one embodiment, the second zone may include a topologically-based need
for
a regenerated energy storage device of the vehicle. For example, the energy
stored in
the energy storage device may be drawn out and used to supply an energy boost
to
climb a hill.
The method may provide for the second operating mode to include operating the
vehicle by drawing stored energy from an energy storage device of the vehicle.
Alternatively, the second operating mode comprises operating the vehicle by
drawing
energy only from an energy storage device of the vehicle and not from an
engine of
the vehicle. Suitable energy storage devices may include batteries, fuel
cells, fly
wheels, ultracapacitors, combinations of the foregoing, and the like. Suitable
batteries
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may include energy batteries, power batteries, or both energy and power
batteries
where the energy to power ratio determines whether the battery is one or the
other.
Suitable energy batteries may include high temperature batteries, such as
metal halide
batteries, aluminum-based batteries, and sodium sulfur batteries. Suitable
power
batteries may include lithium bases, nickel metal hydride, zinc matrix, lead
acid, and
the like.
In one embodiment, the second operating mode may include a process of
determining
a compliant operating mode that is a mixture of energy from an energy storage
device
of the vehicle and from an engine of the vehicle. Once the proportion is
determined,
the controller controls the engine to run in a manner that has at least one of
less noise,
less emissions, or less of a taxable event relative to only the first mode of
operation.
The translation point, static or dynamically defined, may be determined using
a
signal/sensor pair, a global positioning system, or a calculation based on a
known
route and a distance or time/speed measurements along the route. For the
later,
locomotives having well-defined routes may be particularly amenable. A
suitable
signal/sensor pair may include a radio frequency identification (RFID) sensor
and/or
an RFID signal generator. The RFID may be used, for example, so that a zone
boundary (particularly when static) has an RFID component located thereon. The
corresponding RFID part can be located on the vehicle. Depending on the
situation, it
may be more economical to have the sensor or the emitter on the vehicle, and
the
RFID tag can be either active or passive as the application may warrant.
With reference to Fig. 2, another embodiment of the invention includes
defining a
third zone having an associated third characteristic. The method further
includes
switching the vehicle to a third operating mode in the third zone in response
to the
vehicle translating to the third zone from the first zone. The schematic
representation
in Fig. 2 illustrates the zones in an exemplary, but non-limiting, concentric
arrangement - where the first zone is outside of the second zone, and the
third zone
(or charging zone) is shown therebetween. A depot 200 is a starting point for
a
delivery truck 210 that winds on a route 212 through each of the three zones.
The
first travel segment 220 shows an operating mode in which speed and fuel
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consumption are balanced. and maximized. The second travel segment 222 shows
an
operating mode in which the on-board energy batteries are charged up to a
maximum
useable charge and the battery temperature is adjusted. The third travel
segment 224
shows an operating mode in which the engine is shut down and the energy
storage
device supplies electricity to traction motors to drive the vehicle to the
destination
230, and then after a stop to beyond the destination. The fourth travel
segment 232
shows an operating mode in which the engine is restarted and the energy
storage
device is recharged.
The third zone is disposed adjacent to the second zone. The third
characteristic, used
to define the metes and bounds of the third zone, may include a calculated
minimum
travel length to take an energy storage device on the vehicle from a current
state of
charge to a full state of charge. The third zone can extend directly outward
from the
boundary of the second zone; but, as the travel path through the third zone
can be
skew, tortuous or circuitous rather than linear and perpendicular the third
zone need
not be as wide as the minimum length needed for the vehicle to charge up the
on-
board batteries.
Another suitable third characteristic may include a topographical feature
biased for
regenerative braking, such as a downgrade. For the calculation of the minimum
travel
path, several factors may be taken into account. These factors may include:
the
amount of energy needed to traverse the second zone, the amount of additional
energy
that may be taken up by the energy storage device while in the second zone (by
regenerative braking or by a plug-in stop, for example), the time and/or
distance to the
outer boundary of the second zone, the terrain or route conditions leading up
to and
adjacent the second zone, the uptake rate of the energy storage device, the
energy
output of the regenerative braking system, and the like.
The method may include determining a current state of charge of an energy
storage
device of the vehicle and determining a minimum distance for regenerative
braking to
bring the energy storage device from the current state of charge to a full
useable state
of charge. Alternatively or additionally, the method may include adjusting a
route of
the vehicle so that a travel path of the vehicle in the third zone is of
sufficient length
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to charge an energy storage device of the vehicle to a full useable charge
state. In one
embodiment, the travel path through the third zone is adjusted to take
advantage of a
down grade, during which regenerative braking is used to charge the energy
storage
device. The method can further include determining the projected travel path
length
in the second zone, determining a state of charge of an energy storage device
of the
vehicle, determining an expected hybrid propulsion distance based on the
useable
state of charge, and comparing the expected hybrid propulsion distance to the
travel
path length. If the distance that the battery charge can carry the vehicle is
further than
the expected distance in the second zone, then the control system can just
monitor the
battery state and there is no need to top off the energy stored in the energy
storage
device. But, if the energy in the energy storage device appears insufficient,
the
controller can begin a process of charging up the energy storage device.
Suitable
charging regimes can include re-routing to a down grade to use regenerative
braking,
applying an opposing torque on the hybrid axels so that the engine indirectly
charges
the energy storage device "through the road" where the engine supplies more
propulsive power than is needed for propulsion and the hybrid axels
simultaneously
brake to re-charge, or the energy storage device communicates with the
alternator to
charge directly therefrom. Using one of the foregoing methods, it is possible
to
charge the energy storage device to a full useable state of charge in the
third zone
prior to translating to the second zone.
To optimize the recharging process, the regenerative braking may take into
account a
component limiting factor. For example, the energy storage device may have an
energy uptake of a particular rate. The method, then, may slow the vehicle
using
regenerative braking at a rate that is determined by the energy uptake rate of
the
energy storage device or, as another example, the energy generating capacity
of a
regenerative braking system coupled thereto.
In one embodiment, the first operating mode includes operating an auxiliary
electrical
system in a first, higher-energy consuming operating mode. The second
operating
mode can include operating the auxiliary electrical system a second, lower-
energy
consuming operating mode. In this manner, it may be possible to use larger
amounts
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of electrical energy where there is an abundance, and when there is a finite
supply (for
example, a finite battery capacity) change to a reduced electrical consumption
operating mode. This may allow more electrical energy to be directed to
propulsive
effort in the second zone.
Methods according to the present invention may be implemented by an
electrically
drivable vehicle. The vehicle may include at least a controller and a sensor.
The
controller can switch an operating mode of the vehicle from a first operating
mode in
a first zone to a second operating mode in a second zone. The mode switch may
be in
response to the vehicle translating from the first zone to the second zone.
The sensor
communicates with the controller, and informs the controller if the vehicle
translates
to and from the second zone. The vehicle may include an energy storage device
that
can propel, or assist in propelling, the vehicle in at least one mode of
operation. In
one embodiment, the energy storage device is not electrically coupled to an
engine-
driven alternator. An example may include a hybrid locomotive where two of the
six
traction motors are decoupled from the DC link and re-routed to the energy
storage
device. Alternatively, the vehicle may be a plug-in hybrid and not have an
engine. In
an illustrative embodiment, the vehicle is a diesel electric hybrid
locomotive. Other
suitable vehicles may include off-highway vehicles, marine vehicles, busses,
vans,
tractor-trailer rigs, and passenger vehicles. Each vehicle type, naturally,
has differing
needs and requirements associated therewith - such as voltage requirements,
emissions regulations, maintenance needs, and travel patterns.
In one embodiment, the vehicle may further include a fuel cell that is
operable to
supply energy to an auxiliary electrical system or an electrical vehicle
accessory
system. The fuel cell may be electrically coupled directly to the energy
storage device,
or may be routed through a boost converter. Alternatively, the fuel cell may
be
coupled to a traction drive motor so that the fuel cell energy may supplement
the
propulsive effort of the vehicle, as needed or desired.
In another embodiment, a system is provided that has information correlating
an
amount of energy used by a vehicle to an amount of fuel consumed by the
vehicle or
an amount of emissions emitted by the vehicle. That is, based on an amount of
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electrical energy used to drive propulsive motors, the information correlates
that
energy amount to an amount of fuel needed to generate that amount of energy
either
by an on-board engine or by an engine in another vehicle. The system includes
a
controller and a sensor. The sensor can measure either an amount of energy
supplied
by an energy storage device, or an amount of energy consumed by a propulsive
traction motor. The sensor can communicate information about that supplied or
consumed energy amount to the controller. The controller can determine, based
on
the correlation data, a saved amount of fuel or a reduced amount of emissions
based
on the amount of the energy supplied by the energy storage device or consumed
by
the traction motor.
Optionally, in the system, at least a portion of the energy supplied by the
energy
storage device was provided to the energy storage device by regenerative
braking of
the vehicle. The correlating information can refer to an engine only propelled
vehicle
that consumes fuel and emits emissions, so that the amount of fuel saved or
emissions
reduced is an amount referring to the instant vehicle relative to the engine
only
propelled vehicle. A display screen can be secured to the vehicle that
displays the
amount of fuel not consunied by the vehicle or an amount of emissions not
emitted by
the vehicle, relative to operation of that vehicle, or another like vehicle,
not operating
in a particular fuel or emissions saving mode.
A vehicle having a control system that can implement a method according to an
embodiment of the invention may have a distributed energy storage system. A
prime
mover supplies electrical power to first or conventional traction drives,
while the
remaining second or hybrid traction drives are electrically powered via one or
more
energy storage devices. During periods of extended high motive power operation
when the energy stored in the energy storage unit is sufficiently depleted,
the
controller may allow power from the prime mover to be used in the propulsion
drives
that were initially powered from the energy storage units.
During braking events, where a traction drive torque command is in the
opposite
polarity as required for traction drive operation in a motoring mode, a
portion of the
regenerative braking energy may be captured in the energy storage units, this
is
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"through the road" charging of the energy storage device. High power
regenerative
braking energy can be captured in the energy storage system until a determined
charge
or voltage limit is attained. Then, the energy can be dissipated in a
conventional
dynamic brake grid as waste heat. Likewise, during extended periods of
operation at
high motive power when the energy storage unit depletes, the power control
apparatus
directs the prime mover to supply power using energy from the on-board engine.
Selection of the electrical configuration provides that the system can propel
the
vehicle at relatively lower speeds and potentially high torques by using the
second
traction drive system, and the system can propel the vehicle at relatively
higher speeds
and moderate torques by using at least the first traction drive system.
Particularly, at
higher speeds or under heavy load conditions (heavy haul, high speed, or steep
grade)
energy can be pulled out of the energy storage device to power the second
traction
drive system in conjunction with the motive power supplied by the first
traction drive
system.
The auxiliary electrical system may be electrically connected to the energy
storage
device. The auxiliary electrical system can supplement a prime auxiliary
electrical
system by supplying electrical energy to the prime auxiliary electrical
system,
especially during periods when regenerative energy is extracted from the
traction
drive systems. The auxiliary electrical system can supplement the prime
auxiliary
electrical system by supplying electrical energy to some subcomponents while
the
prime auxiliary electrical system supplies electrical energy to other
subcomponents.
One example is that the auxiliary electrical system can operate critical
auxiliary
components while the prime auxiliary electrical system is disabled or shutdown
to
eliminate noise or emissions, or to reduce fuel consumption by the engine.
Output voltage from the engine driven alternator may be controlled based on
vehicle
speed, traction torque, and load. Depending on energy storage device and load,
propelling an electrically driven vehicle at a first, slower speed and
potentially high
torque, can be performed using the second electric motor alone, i.e. Electric
Vehicle
mode (EV), or in combination with the engine-driven alternator to a first
electric
motor, i.e. Hybrid Electric Vehicle Mode (HEV). Of note is that differing
voltages
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may be implicated by different end uses. Passenger cars and light duty trucks
may
utilize a voltage of about 200 volts to about 400 volts; medium duty trucks,
vans, and
busses may utilize a voltage of about 500 to about 650 volts; and locomotives
may use
voltages of up to about 1400 volts.
In one embodiment, the control system can initiate a braking event calling for
an
amount of a required braking power. The first available braking power can be
based
on a component limiting factor determined by at least one of: power capacity
of the
first traction motor, electrical uptake capacity of the energy storage device,
electrical
rating capacity of an electronic inverter, or electrical rating capacity of a
power
switch. The first available braking power is compared to the required braking
power.
The required braking power can be first met with the first available braking
power.
The first available braking power can be supplemented with a second available
braking power if the first available braking power is insufficient to meet the
required
braking power. The second available braking power can be based on at least a
capacity of a dynamic braking grid resistor array coupled the second traction
motor.
In one embodiment, the method may further include charging the energy storage
device by converting mechanical energy during a braking mode of operation of
the
second electric motor to electrical energy. An operating mode may be selected
for use
in which a greater than full motive power propels the vehicle relative to
another
operating mode in which power from a prime mover combines with energy supplied
from one or more energy storage devices. Alternatively, an operating mode may
be
selected in which all of the propulsive power supplied to one or more traction
motors
is energy supplied from one or more energy storage devices. Another operating
mode
is provided in which all propulsive power supplied to one traction motor is
energy
supplied from one or more energy storage devices, and in which all propulsive
power
supplied to another traction motor is energy supplied from an alternator.
Another method according to embodiments of the invention may include
initiating a
braking event calling for an amount of a required braking power. A first
available
braking power may be determined based on a component limiting factor
determined
by at least one of: power capacity of an electric motor, electrical uptake
capacity of an
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energy storage device, electrical rating capacity of an electronic inverter,
or electrical
rating capacity of a power switch; and comparing the first available braking
power to
the required braking power. "The required braking power may be supplied first
with
the first available braking power. As needed, the first available braking
power can be
supplemented with a second available braking power. The second available
braking
power is based on at least a capacity of a dynamic braking grid resistor array
coupled
thereto. Optionally, the energy storage device can include an energy battery,
and a
power battery that has a relatively faster uptake of energy than the energy
storage
battery. The regeneratively captured energy can be routed to the power device
with or
without routing to the energy battery. From there, the energy can be fed from
the
power battery to the energy battery at a rate of uptake that the energy
battery can
handle.
While examples were given with some reference to locomotives, the propulsion
system may be useful in other vehicle types. Other suitable vehicles may
include
passenger vehicles; medium or light duty vans and trucks; busses and heavy
duty
trucks and construction equipment; off-highway vehicles (OHV); and boats,
ships and
submarines.
The embodiments described herein are examples of structures, systems and
methods
having elements corresponding to the elements of the invention recited in the
claims.
This written description may enable those of ordinary skill in the art to make
and use
embodiments having alternative elements that likewise correspond to the
elements of
the invention recited in the claims. The scope of the invention thus includes
structures, systems and methods that do not differ from the literal language
of the
claims, and further includes other structures, systems and methods with
insubstantial
differences from the literal lariguage of the claims. While only certain
features and
embodiments have been illustrated and described herein, many modifications and
changes may occur to one of ordinary skill in the relevant art. The appended
claims
cover all such modifications and changes.
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