U.S. patent application number 10/051304 was filed with the patent office on 2005-06-02 for optimization method for power generation systems.
This patent application is currently assigned to Athena Technologies, Inc.. Invention is credited to Russ, Benjamin, Vos, David.
Application Number | 20050118021 10/051304 |
Document ID | / |
Family ID | 26733001 |
Filed Date | 2005-06-02 |
United States Patent
Application |
20050118021 |
Kind Code |
A2 |
Vos, David ; et al. |
June 2, 2005 |
OPTIMIZATION METHOD FOR POWER GENERATION SYSTEMS
Abstract
Apparatus for controlling the power output efficiency of a power
generation system based on an operator input. A processor is
coupled to the input means and (i) receives the generated operator
command, (ii) receives a plurality of detected ambient air
conditions, (iii) receives a plurality of detected engine
performance parameters, (iv) determines first and second engine
control commands based on the received pilot thrust command, the
detected ambient environmental conditions, and the engine
performance parameters, and (v) outputs control commands to
optimize the efficiency of the power generation system.
Inventors: |
Vos, David; (Delaplane,
VA) ; Russ, Benjamin; (Catlett, VA) |
Correspondence
Address: |
FINNEGAN, HENDERSON, FARABOW, GARRETT & DUNNER LLP
901 NEW YORK AVENUE, NW
WASHINGTON
DC
20001-4413
US
|
Assignee: |
Athena Technologies, Inc.
Vint Hill Tech Park 6786 Watson Ct.
Warrenton
VA
20187
|
Prior
Publication: |
|
Document Identifier |
Publication Date |
|
US 0131864 A1 |
September 19, 2002 |
|
|
Family ID: |
26733001 |
Appl. No.: |
10/051304 |
Filed: |
January 22, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10051304 |
Jan 22, 2002 |
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09/729,457 |
Dec 5, 2000 |
|
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6,340,289 |
Jan 22, 2002 |
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09/729,457 |
Dec 5, 2000 |
|
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09/054,411 |
Apr 3, 1998 |
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6,171,055 |
Jan 9, 2001 |
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Current U.S.
Class: |
416/25 |
Current CPC
Class: |
B60W 20/00 20130101;
F02C 9/00 20130101; Y02T 10/62 20130101; F05D 2270/051 20130101;
B60W 2555/20 20200201; B60W 20/11 20160101; F02C 9/58 20130101;
F05B 2270/1033 20130101; F02D 29/02 20130101; F05B 2240/132
20130101; F05D 2270/053 20130101; B60W 10/08 20130101; F02D
2200/0408 20130101; F02D 2200/704 20130101; F05B 2270/1031
20130101; F03D 9/25 20160501; F02C 9/44 20130101; Y02T 10/6286
20130101; F02C 9/48 20130101; F02D 41/021 20130101; B60W 10/06
20130101 |
Class at
Publication: |
416/025 |
International
Class: |
F01D 007/00 |
Claims
What is Claimed is:
1. Single input power control apparatus for controlling a
powerplant, comprising: an input means for generating a output
power command; and a processor, coupled to said input means, for
(i) receiving the generated output power command, (ii) receiving a
plurality of detected ambient air conditions, (iii) receiving a
plurality of detected powerplant performance parameters, (iv)
determining first and second powerplant control commands based on
the received output power command, the detected ambient air
conditions, and the powerplant performance parameters, and (v)
outputting first and second output signals respectively
corresponding to the first and second powerplant control
commands.
2. Apparatus according to Claim 1, wherein said detected ambient
air conditions include humidity and air pressure.
3. Apparatus according to Claim 1, wherein said first powerplant
control command comprises a powerplant speed command, and wherein
said second powerplant control command comprises a powerplant load
command.
4. Apparatus according to Claim 3, wherein said powerplant load
command comprises a manifold air pressure command.
5. Apparatus according to Claim 4, wherein said powerplant speed
command comprises a gear box RPM command.
6. Apparatus according to Claim 5, wherein said plurality of
detected engine performance parameters include gear box RPM and
manifold air pressure.
7. Apparatus according to Claim 1, wherein said processor (i)
stores plural sets of first and second powerplant control
parameters which yield highest output power efficiency for detected
ambient air conditions and output power commands, and (ii) selects
the one set of first and second powerplant control commands which
corresponds to the detected ambient air conditions and the received
output power command.
8. A wind turbine control apparatus comprising: a propeller coupled
to an electrical generator; a load coupled to said electrical
generator for the transmission of electricity; a processor, coupled
to said wind turbine, for (i) receiving a plurality of detected
ambient air conditions, (ii)receiving a plurality of detected wind
turbine performance parameters, (iii) determining a control command
based on the detected ambient air conditions, and the wind turbine
performance parameters, and (iv) outputting a control signal
corresponding to the control command.
9. The apparatus of Claim 8, further comprising a pitch servo for
(i) receiving said control signal, and (ii) changing the pitch of
said propeller corresponding to the control command.
10. The apparatus of Claim 8, further comprising a variable speed
gear box for (i) receiving said control signal, and (ii) changing
the rotational speed of said propeller corresponding to the control
command.
11. The apparatus of Claim 8, further comprising a load shedding
means coupled to said generator for (i) receiving the control
signal (ii) varying the load coupled to said generator to optimize
the performance of the wind turbine.
12. Apparatus according to Claim 8, wherein said processor (i)
stores plural sets of wind turbine control parameters which yield
highest output power efficiency for detected ambient air conditions
and (ii) selects the one set of control commands which corresponds
to the detected ambient air conditions.
13. Single input power control apparatus for controlling a ground
vehicle, comprising: an input means for generating a output power
command; and a processor, coupled to said input means, for (i)
receiving the generated output power command, (ii) receiving a
plurality of detected ambient air conditions, (iii) receiving a
plurality of detected engine performance parameters, (iv)
determining first and second engine control commands based on the
received output power command, the detected ambient air conditions,
and the engine performance parameters, and (v) outputting first and
second output signals respectively corresponding to the first and
second engine control commands.
14. Apparatus according to Claim 13, wherein said detected ambient
air conditions include ground speed and air pressure.
15. Apparatus according to Claim 13, wherein said first engine
control command comprises an engine speed command, and wherein said
second engine control command comprises an engine load command.
16. Apparatus according to Claim 15, wherein said engine load
command comprises a manifold air pressure command.
17. Apparatus according to Claim 16, wherein said engine speed
command comprises a gear box RPM command.
18. Apparatus according to Claim 17, wherein said plurality of
detected engine performance parameters include gear box RPM and
manifold air pressure.
19. Apparatus according to Claim 13, wherein said processor (i)
stores plural sets of first and second engine control parameters
which yield highest output power efficiency for detected ambient
air conditions and output power commands, and (ii) selects the one
set of first and second engine control commands which corresponds
to the detected ambient air conditions and the received output
power command.
Description
Detailed Description of the Invention
RELATED APPLICATION
[0001] This application is a continuation-in-part of Patent
Application No. 09/729,457 filed December 5, 2000, now U.S. Patent
No. 6,340,289, which is a continuation of Patent Application No.
09/054,411 filed April 3, 1998, now U.S. Patent 6,171,055, and is
incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field Of The Invention
[0003] The present invention relates to method and apparatus for
controlling the output of a power generation system using a single
input power controller.
[0004] 2. Related Background
[0005] In the field of engine control, many proposals exist for
controlling the flow of fuel to the engine in accordance with
detected engine operating parameters such as engine temperature,
engine pressure ratio, shaft speed, etc. to maximize fuel
efficiency, but such proposals fail to take into account the
ambient operating conditions. Proposals of this type are described
in U.S. Patent Nos. 4,248,042; 4,551,972; 4,686,825; 5,029,778;
5,039,037; 5,277,024; and 5,613,652. However, even if such systems
were adapted to power generation systems such as used by electric
utilities, technicians would still be required to operate and
continually adjust a plurality of control levers to optimize engine
output for given environmental conditions.
[0006] By 1985, it was recognized that aircraft engine efficiency
is highest when the engine is run with the throttle butterfly valve
fully open and the desired performance is obtained by varying
propeller speed. See, for example, SAE Technical Paper Series
850895, The Porsche Aircraft Engine P F M 3200", Helmuth Bott and
Heinz Dorsch, 1985. This article proposed a single-lever control
system for an aircraft engine that operates both the throttle and
the propeller governor with a single lever. However, the proposed
system is a mechanical linkage system which accordingly cannot
optimize engine performance based on various ambient flight
conditions. That is, the Porsche system may work well at a single
altitude, speed, and temperature, but will seriously degrade at
other flight conditions.
[0007] Similarly, it may be advantageous in a power generation
system, to allow the prime mover or engine to operate at a full
throttle condition, while manipulating the attached electrical
generator and/or connecting gear box to achieve maximum efficiency
based on current environmental parameters. This approach may also
be applied to wind turbine application as well as propulsion
systems for ground vehicles.
SUMMARY OF THE INVENTION
[0008] The present invention is intended to overcome the drawbacks
of known power generation control systems by providing a
processor-controlled system which inputs a single power command,
receives detected ambient environmental conditions, and
automatically controls the engine/generator output, and engine load
(e.g., manifold air pressure (MAP)) for the detected environmental
conditions relative to the requested power command.
[0009] According to a first aspect of the present invention, a
single input power control apparatus for controlling a poker
generation system includes a single, manually-operable input for
generating a power level generation command. A processor receives
the generated power level command, receives a plurality of detected
ambient air conditions, and determines an engine speed activation
command and an engine load activation command based on the maximum
output power efficiency for the detected ambient environmental
conditions and power level command. In one embodiment, the output
power efficiency optimization is performed off-line where the
processor accesses a look-up table which stores highest output
power efficiency values for the detected environmental conditions
and power level command. In another embodiment, the optimization is
performed on-line where the processor determines the highest output
power efficiency values by varying the existing values and
determining any change in the power output. A positive change
indicates more efficient output power values, and these will be
used to control the engine.
[0010] Similarly, according to a further aspect of the present
invention, control apparatus for use with a wind power generator
control device includes an electrical power generator connected to
a propeller of a wind turbine. A processor receives a generated
power level command, receives a plurality of detected ambient air
conditions, and determines a gear box speed activation command and
a propeller load activation command based on the maximum output
power efficiency for the detected ambient environmental conditions
and power level command. Output from the wind turbine is
automatically controlled by altering the pitch of the turbine
blades in accordance with the output of the processor, thereby
selecting the most efficient operating condition for the wind
turbine.
[0011] According to another aspect of the present invention,
apparatus for controlling a ground vehicle engine having an
internal combustion engine and an air inlet includes a single,
manually-activated structure for providing an engine thrust command
such as an accelerator pedal or a remote command in the case of an
unmanned vehicle. A processor is provided for receiving the engine
output command and detected ambient air conditions, and determines
first and second control commands for the engine. The processor
determines the first and second control commands based on the
received engine output command, the detected ambient air
conditions, and a maximum engine output efficiency value for the
detected ambient air conditions.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The novel structure and functions according to the present
invention will become readily apparent to those of ordinary skill
in the art from the following detailed description of the preferred
embodiments taken together with the accompanying drawings which
show:
[0013] Figure 1 is a block diagram of the power generation
structure according to one embodiment of the present invention;
[0014] Figure 2 is a functional block diagram of the embodiment
depicted in Fig. 1;
[0015] Figures 3 is a block diagram of the wind turbine control
structure according to another embodiment of the present
invention;
[0016] Figure 4 is a block diagram of another preferred embodiment
directed at power generation systems for ground vehicles;
[0017] Figure 5 is a contour map representing output power vs. MAP
vs. RPM in accordance with the embodiment shown in FIG. 1;
[0018] Figure 6 is a contour map showing constant output power in
accordance with the embodiment shown in FIG. 1;
[0019] Figure 7 is a graph showing the constrained maximum output
power efficiency in accordance with the embodiment shown in FIG.
1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0020] 1. Introduction
[0021] Power plants for power generation are typically comprised of
a plurality of prime power sources such as turbine engines, gas
powered internal combustion engines and the like each connected to
a generator through a variable speed transmission/gear box. The
engine burns fuel thereby converting the fuel into electrical
energy that is in turn produced by the generator. The efficiency of
the power generation system may be improved by monitoring
environmental parameters and selecting setpoints for controlling
engine speed and generator output based on the known performance of
the system.
[0022] Similarly, a wind turbine produces electrical energy by
converting the energy in the wind into rotation of a propeller
which is connected to an electrical generator by a variable speed
transmission. Wind turbine power generators, however, do not always
operate at maximum efficiency based on measurable environmental
conditions and operating parameters. Overall wind turbine operating
efficiency may be improved by monitoring the environmental
parameters and selecting setpoints of the wind turbine and the
generator/gear box to provide maximum output power efficiency.
Alternatively, if power shedding capabilities exist, the load on
the generator may be varied to also maximize wind turbine
efficiency.
[0023] In yet another example of power generation, a prime mover
such as an internal combustion engine is provided in a ground
vehicle to transmit power to the wheels of the vehicle to move the
vehicle along the ground at some desired speed. Overall prime mover
efficiency may be improved by monitoring operating parameters such
as transmission/wheel speed and engine speed to find the optimum
operating setpoints for the engine and/or transmission.
[0024] The present invention dovetails nicely with the advances
recently made in electronic control of engine parameters such as
fuel mixture, operating temperature, etc. Engine control units
(ECU=s) and power plant control units (PCU`s) are used in the
automotive industry to digitally fine-tune fuel consumption in the
power plant.
[0025] While the present invention is described with respect to
power generation systems such as wind turbines and ground vehicles,
those skilled in the art will appreciate that other applications
may include many other well known power generation systems.
[0026] 2. The Structure
[0027] Fig. 1 depicts the structure according to a preferred
embodiment of the present invention in which prime power source 2
comprises a known prime power source for use in power generation
stations, for example, a gas fired internal combustion engine, a
high speed turbine engine or the like. An electrical generator 3 is
connected to the prime power source 2 by a gear box 5. The gear box
5 may be a variable speed transmission that can be controlled by an
output from the controller. Load 4 may comprise any known
electrical power transmission means for transmission of the
electrical power generated by the generator 3.
[0028] Prime power source 2 has an intake manifold 10 and an
exhaust manifold 12. The exhaust manifold 12 has two branches, a
branch 14 which may provide output to an optional turbo charger
(not shown), and a branch 16 which is vented to the atmosphere. An
optional movable waste gate 18 controls the balance of exhaust
gases between branch 14 and 16 so as to control the amount of
exhaust gases provided to the turbo charger 14. A waste gate servo
20 controls the position of the waste gate valve 18 in accordance
with feedback from the measured intake manifold pressure (to be
described below).
[0029] The intake manifold 10 has a movable throttle valve 22 which
is controlled by a throttle servo 24. A manifold air pressure (MAP)
sensor 26 detects the intake manifold air pressure.
[0030] The control electronics are encompassed in a Full Authority
Digital Electronic Control (FADEC) 30. The FADEC 30 includes, inter
alia, a CPU unit 32, a ROM 34, and a RAM 36. In the present
embodiment, the FADEC 30 is a 16 bit microcontroller based on the
Intel 8096 microprocessor which was used in previous generations of
Ford engine ECU`s. The fuel is metered and fuel injection is
controlled by the FADEC using the speed-density method. The system
features distributorless electronic ignition with double fire
capacity. The FADEC controller is housed in a sealed enclosure with
liquid cooling for high altitude applications. The integration of
the single input power controller (SIPC) software was found, in the
present embodiment, to be most efficient as a sub-routine of the
FADEC control program. The SIPC subroutine receives the relevant
power plant parameters (to be discussed below), performs the SIPC
algorithms (also to be discussed below) and delivers control
parameters at the end of each control cycle. The FADEC software
also controls engine performance parameters such as injection,
spark, mix, etc. (To be discussed below)
[0031] Inputs to the FADEC which are used in the SIPC algorithm
include environmental condition inputs such as the humidity 38, the
ambient air pressure 40, and the ambient air temperature 42. Input
from the single input 44 is provided to the FADEC 30 through the
line 46.
[0032] The FADEC 30 receives inputs from the various engine control
sensors and provides control outputs to the various servos as
depicted in Fig. 1. Specifically, the CPU 32 outputs throttle servo
commands to the throttle servo 24, and receives MAP sensor signals
from the MAP sensor 26. The CPU 32 also receives RPM sensor signals
from the RPM sensor 8.
[0033] For controlling the engine performance parameters, the CPU
32 also receives a number of engine status parameters such as
Exhaust Gas Temperature (EGT), Cylinder Head Temperature signals
(CHTs), Universal Exhaust Gas Oxygen sensor signals (UEGO), Air
Charge Temperature signals (ACT), Mass Airflow signals (MAF), and
the Exhaust Pressure Signals (PEXH), over a bus 50. In the
preferred embodiment, these signals comprise analog signals which
may vary between -10 and +10 volts, preferably + or - 5 volts, or
as available.
[0034] The CPU 32 outputs to the prime power source 2 control
signals to control the injectors, the spark, and the fuel/air mix,
on a bus 52. Again, in the preferred embodiment, the signals are
analog signals varying between 0 and 5 volts, or as required. Of
course, some or all of the signals provided into and out of the
FADEC may be digital signals.
[0035] A display 54 may be coupled to the FADEC 30 to display the
MAP command and/or the generator RPM command. For example, where
the system according to the present invention is advisory only and
does not actually output commands to change engine and generator
performance, displayed MAP and RPM commands may provide the
operator with suggested settings for the throttle servo 24.
[0036] 3. The Functions
[0037] Fig. 2 is a functional block diagram showing the salient
features of the SIPC algorithm. Briefly, the FADEC 30 (Fig. 1)
receives both the detected environmental conditions and the
commanded power output, and uses these values to access one or more
look-up tables stored in ROM 34 or RAM 36. The look-up table will
provide an RPM command and a MAP command which will achieve the
best output power efficiency for the detected values. The control
algorithm and the look-up tables can be loaded into an existing
computer from a disk. Alternatively, the algorithm and look-up
tables may be provided in a separate computer to provide the
operator with an advisory message rather than activate the control
servos.
[0038] In more detail, the system constantly monitors the air data
60, thus knowing the ambient air conditions. This information is
employed in the control mixing algorithm 62 to select the optimum
combination of the engine speed and power (or load) setting to
maximize the output power efficiency achieved, i.e., maximum
efficiency of the combined prime power source and generator at the
detected environmental condition.
[0039] In operation, the operator commands the desired output power
percentage 64 by using the single input means 44 (Fig. 1). The
control mixing algorithm (preferably, a software subroutine running
in the FADEC 30) transforms the input output power percentage into
a MAP set point to control the engine power/load controller 66
which, in the proposed embodiment, drives the throttle servo 24 and
the waste gate servo 20 (Fig. 1) to achieve the desired inlet
manifold pressure. On non-turbo charged engines, the throttle servo
alone is driven to achieve the desired inlet manifold air pressure.
The control algorithm 62 also outputs a generator speed set point
(RPM) to the generator speed controller 68 which, in the preferred
embodiment, includes gear box servo 6, to control generator speed
by actuating the variable speed transmission until the measured
speed matches the speed set point.
[0040] With the desired output power indicated by the input 44, the
control mixing algorithm 62 interpolates stored tabulated data (to
be discussed below) to determine the MAP and RPM that will maximize
output power efficiency at this commanded output power level. Such
an interpolation must be handled very carefully, since the optimum
MAP and RPM positions may not follow well-defined, linear
functions. For example, the optimum conditions may follow irregular
boundaries of MAP and RPM.
[0041] The power output of prime power source 2 is controlled in
operation by two primary variables, MAP and RPM. The power output
and specific fuel consumption are characterized by testing and/or
prediction as functions of MAP and RPM. The generator is
characterized by maps of power coefficient and efficiency versus
advance ratio, which in turn are functions of RPM, density, and
load. The optimization algorithm maximizes the output power
efficiency of the combined power generation system.
[0042] Since the final output of the optimization algorithm is a
set of RPM and MAP data versus environmental conditions and output
power, these data are stored in the FADEC 30 in 109k-up table form
and read directly or interpolated to obtain optimum conditions at
any environmental condition and output power. In Fig. 5, a
constant-output power contour is obtained for the commanded power
output and the detected ambient air operating conditions. This
contour is projected onto the RPM-MAP plane. For this example, the
contour is represented by a series of points describing
intersections with the RPM-MAP grid lines. In Fig. 6, the RPM-MAP
contour pairs are mapped onto the output power efficiency curve.
The output power contour is re-projected onto the thrust efficiency
surface, and the result of the operation is a discrete 3D curve. In
Fig. 7, the maximum output power efficiency may be constrained for
safety and other operating conditions. For example, a
safe-operating envelope may be imposed on the projected output
power efficiency curve, and the maximum output power efficiency
within the constraint is located to yield RPM/MAP setpoints to
control the engine and propeller.
[0043] In more detail, the SIPC described earlier automatically
selects MAP and RPM values for a desired power setting, where the
MAP and RPM values are predetermined in an off-line optimization
process and stored in the FADEC look-up table. This allows the
system to get close to the optimum power generation efficiency,
except for the effects of uncertainty in the models used in the
off-line optimization. The on-line optimization algorithm discussed
above fine tunes the base off-line optimization to achieve true
optimal power generation efficiency by continually seeking the
optimum in real time. This process also corrects for
engine/generator wear and part replacements.
[0044] These control principles apply equally as well in other
power generation systems. For example, in the case of a wind
turbine, the prime power source 2 is replaced by the wind and a
propeller. FIG. 3 (where like items have like numerals) shows a
block diagram of a wind turbine system. In this embodiment, a
generator 3 is connected to a propeller 4a via a gear box 5. A load
9 is connected to the generator and is comprised of well known
electrical transmission means. In this embodiment, environmental
conditions are monitored as inputs to controller 30a. A pitch servo
6 is connected to the propeller 4a and is selectably actuated to
change the pitch of the propeller blades thereby altering the
rotational speed of the propeller. Similar to the previous
embodiment, the control algorithm selects the optimum operating
speed based on the known performance of the wind turbine and the
measured environmental parameters and generates a control signal to
the pitch servo 6. Alternatively, the gear box 5 may be a variable
speed transmission that may control the operating speed of the
generator 3. This gear box control may be in combination with the
propeller pitch control or used alone as a means to provide the
optimum power generation. A control signal from the controller 30a
to the variable speed transmission based on the measured parameters
will be provided to select the optimum generator speed for maximum
power generation. Still further, it may be advantageous to provide
load shedding means 11 connected to the generator 3 to further
optimize the operating efficiency of the wind turbine. In this
arrangement, CPU 32 would provide a control signal to the load
shedding means 11 to change the flow of electrical power in the
most efficient manner based on the measured operating parameters
and environmental conditions.
[0045] Still further, the aforementioned control system may be
applied to ground vehicles. Referring to FIG. 4, where like items
have like numerals, a ground vehicle is provided with an engine 2a
connected to a transmission 5a. The transmission is connected to a
plurality of wheels 7 that are in contact with the ground. The
engine 2a consumes fuel and propels the vehicle along the ground in
accordance with an input command 44 from an operator.
Alternatively, the ground vehicle could be unmanned. Optimum
operating setpoints for the engine 2a and transmission 5a are
determined based on an algorithm stored on the FADEC 30 as
previously discussed. This system could easily be applied to hybrid
electrical vehicles, fuel cell powered vehicles, battery powered
vehicles and vehicles with continuously variable transmissions.
Optionally, a control signal may be provided to the transmission 5a
to alter the transmission`s settings and further provide a means
for optimizing the power generation from the engine 2a.
[0046] 4. Conclusion
[0047] The input power controller structure and functions described
above can simplify operational tasks and greatly improve engine and
power generation performance by selecting the best efficiency for
the commanded thrust and detected environmental/operating
conditions.
[0048] The individual components shown in outline are designated by
blocks in the Drawings are all well-known in the engine control
arts, and their specific construction and operation are not
critical to the operation or best mode for carrying out the
invention.
[0049] While the present invention has been described with respect
to what is presently considered to be the preferred embodiments, it
is to be understood that the invention is not limited to the
disclosed embodiments. To the contrary, the invention is intended
to cover various modifications and equivalent arrangements included
within the spirit and scope of the appended claims. The scope of
the following claims is to be accorded the broadest interpretation
so as to encompass all such modifications and equivalent structures
and functions.
* * * * *