U.S. patent application number 09/797342 was filed with the patent office on 2001-11-29 for pneumatic/mechanical actuator.
This patent application is currently assigned to QUOIN INTERNATIONAL, INC.. Invention is credited to Jacobson, Michael Dean.
Application Number | 20010045093 09/797342 |
Document ID | / |
Family ID | 26881231 |
Filed Date | 2001-11-29 |
United States Patent
Application |
20010045093 |
Kind Code |
A1 |
Jacobson, Michael Dean |
November 29, 2001 |
Pneumatic/mechanical actuator
Abstract
A pneumatic/mechanical actuator described herein consists of a
variation of a Brayton-cycle machine for generating actuation
force. The system avoids the continues heat problem of a
Brayton-cycle by using compressed gas to drive a reversible
turbine. The turbine only is driven when a change of actuation
position. The system includes an internal-combustion engine-air
compressor, a pneumatic energy storage and transfer system, a
fuel/air mixing means, two electric pilot valves, two lean-ratio
high-pressure catalytic-bed burners, a small-diameter and
reversible turbine, a ratio speed-reducing transmission, an
optical-encoder feedback position and speed sensor and a ball-screw
push-rod mechanism. An alternative embodiment uses a free piston
engine compressor hybrid to provide the compressed air. Manual or
computer control may be used to monitor and direct desired changes
in actuator position.
Inventors: |
Jacobson, Michael Dean;
(Ridgecrest, CA) |
Correspondence
Address: |
Kenneth G. Pritchard
P. O. Box 306
Ridgecrest
CA
93556
US
|
Assignee: |
QUOIN INTERNATIONAL, INC.
|
Family ID: |
26881231 |
Appl. No.: |
09/797342 |
Filed: |
February 28, 2001 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
60185537 |
Feb 28, 2000 |
|
|
|
Current U.S.
Class: |
60/602 |
Current CPC
Class: |
F01D 1/30 20130101; Y02E
60/16 20130101; Y02E 60/15 20130101; F02C 6/16 20130101; F02D 29/04
20130101 |
Class at
Publication: |
60/602 |
International
Class: |
F02D 023/00 |
Claims
What is claimed is:
1. A machine for generating actuation force with rapid, precise,
and large displacement motion comprising: a power source; a
pneumatic power supply system operably connected to said power
source for providing compressed air; an electric power source
connected to said power source such that said electrical power
source is recharged as needed by said power supply; an actuation
system with a push rod connected to said power supply, said
pneumatic power supply, and said electrical power supply such that
said push rod is moved in a desired manner; and a control operator
connected to said actuator system to direct changes to the motion
of said push rod in a predictable manner.
2. An actuation force machine as described in claim 1 where said
power source comprises an internal combustion engine, and a fuel
supply.
3. An actuation force machine as described in claim 1 where said
actuator system comprises two burners, a push burner and a pull
burner, each burner connected to said power supply and to said
electrical power supply, said burners each having an exhaust port;
two control valves, one for each burner, each connected to said
pneumatic power source to receive compressed air, each connected to
said control operator such that said control operator can only
activate one of said two control valves at a time, and one of said
control valves feeding compressed air to said push burner and the
remaining of said control valves feeding air to said pull burner; a
reversing turbine operably mounted next to the exhaust port of each
burner such that said reversing turbine spins one direction,
clockwise due to one burner's exhaust port and spins the opposite
direction, counterclockwise due to the second burner's exhaust
port; a speed reducing transmission operably connected to said
reversing turbine to provide a predetermined rate of motion change
to variations in speed of said reversing turbine; and a ball-screw
push rod mounted to said speed reducing transmission for providing
preselected force and motion output.
4. An actuation force machine as claimed in claim 2 where said
actuator system comprises two burners, a push burner and a pull
burner, each burner connected to said power supply and to said
electrical power supply, said burners each having an exhaust port;
two control valves, one for each burner, each connected to said
pneumatic power source to receive compressed air, each connected to
said control operator such that said control operator can only
activate one of said two control valves at a time, and one of said
control valves feeding compressed air to said push burner and the
remaining of said control valves feeding air to said pull burner; a
reversing turbine operably mounted next to the exhaust port of each
burner such that said reversing turbine spins one direction,
clockwise due to one burner's exhaust port and spins the opposite
direction, counterclockwise due to the second burner's exhaust
port; a speed reducing transmission operably connected to said
reversing turbine to provide a predetermined rate of motion change
to variations in speed of said reversing turbine; and a ball-screw
push rod mounted to said speed reducing transmission for providing
preselected force and motion output.
5. An actuation force machine as claimed in claim 1 where said
electrical power supply comprises an alternator driven by said
power supply; and a battery connected to said alternator such that
battery is charged adequately to provide electrical power to said
actuator system.
6. An actuation force machine as claimed in claim 2 where said
electrical power supply comprises an alternator driven by said
power supply; and a battery connected to said alternator such that
battery is charged adequately to provide electrical power to said
actuator system.
7. An actuation force machine as claimed in claim 3 where said
electrical power supply comprises an alternator driven by said
power supply; and a battery connected to said alternator such that
battery is charged adequately to provide electrical power to said
actuator system.
8. An actuation force machine as claimed in claim 4 where said
electrical power supply comprises an alternator driven by said
power supply; and a battery connected to said alternator such that
battery is charged adequately to provide electrical power to said
actuator system.
9. An actuation force machine as described in claim 3 where said
two burners further comprise catalytic-bed combustion reactors.
10. An actuation force machine as described in claim 4 where said
two burners further comprise catalytic-bed combustion reactors.
11. An actuation force machine as described in claim 7 where said
two burners further comprise catalytic-bed combustion reactors.
12. An actuation force machine as described in claim 8 where said
two burners further comprise catalytic-bed combustion reactors.
13. An actuation force machine as claimed in claim 3 where said
reversing turbine has two blade sets one for rotating said turbine
in a clockwise direction and the second blade set for rotating said
turbine in a counterclockwise direction, said configuration of said
two blade sets requiring separate gas input to each to drive said
turbine.
14. An actuation force machine as claimed in claim 4 where said
reversing turbine has two blade sets one for rotating said turbine
in a clockwise direction and the second blade set for rotating said
turbine in a counterclockwise direction, said configuration of said
two blade sets requiring separate gas input to each to drive said
turbine.
15. An actuation force machine as claimed in claim 7 where said
reversing turbine has two blade sets one for rotating said turbine
in a clockwise direction and the second blade set for rotating said
turbine in a counterclockwise direction, said configuration of said
two blade sets requiring separate gas input to each to drive said
turbine.
16. An actuation force machine as claimed in claim 8 where said
reversing turbine has two blade sets one for rotating said turbine
in a clockwise direction and the second blade set for rotating said
turbine in a counterclockwise direction, said configuration of said
two blade sets requiring separate gas input to each to drive said
turbine.
17. An actuation force machine as claimed in claim 11 where said
reversing turbine has two blade sets one for rotating said turbine
in a clockwise direction and the second blade set for rotating said
turbine in a counterclockwise direction, said configuration of said
two blade sets requiring separate gas input to each to drive said
turbine.
18. An actuation force machine as claimed in claim 12 where said
reversing turbine has two blade sets one for rotating said turbine
in a clockwise direction and the second blade set for rotating said
turbine in a counterclockwise direction, said configuration of said
two blade sets requiring separate gas input to each to drive said
turbine.
19. An actuator force machine as claimed in claim 3 where said
actuator system further comprises an optical encoder position and
speed feedback sensor connected to said speed reducing transmission
to monitor the speed and direction of said speed reducing
transmission and also having said sensor output fed to said control
operator.
20. An actuation force machine as described in claim 1 where said
power source and pneumatic power supply comprises a hybrid
engine-compressor free piston having two opposing pistons in a
housing with a single engine compartment, two bounce chamber
compressors one connected to each of said pistons within said
housing such that as said pistons move away from each other each
bounce chamber compressor shows, stops and then pushes said pistons
back towards the other at the same time, a fuel source for
injecting fuel into said engine compartment connected to said
engine compartment, two compression chambers, one each around each
of said pistons, said compression chambers decreasing in volume as
said bounce chamber compressors move said pistons towards each
other; an air transfer chamber which receives air from said two
compression chambers while said pistons are moving towards each
other and which exhausts air into said engine compartment while
said pistons are moving away from one another; a manifold for
venting combustion gases from said engine compartment after
combustion has occurred; and an air intake connected to said
compression chamber for filling them with air while said pistons
are moving apart.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application Ser. No. 60/185,537, filed Feb. 28, 2000, the
disclosure of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates generally to the field of actuation
systems, and more particularly to a pneumatic/mechanical
robotic-system actuator. Specifically, this actuation system
provides efficient and direct chemical (fuel) to mechanical energy
conversion using a combined internal-combustion free-piston or
piston-crank engine-air compressor to generate pressurized air as a
working fluid. The invention further relates to an autonomous power
supply that can support actuation function for long periods of time
using only chemical energy. As in a Brayton-cycle, this is fed
through lean-burn catalytic reactors into a drive turbine to
operate a ball-screw push rod mechanism. The resultant actuator is
thermodynamically efficient, providing significant force in
addition to rapid, precise, and large-displacement motion.
[0004] 2. Description of Prior Art
[0005] Actuators are used in many mechanical systems to produce
motion. The primary types include hydraulic, pneumatic, and
electric motor driven systems. These systems are designed to
provide motive force, rapid motion (with high frequency bandwidth
response) and precise positioning. At the same time such systems
must not sacrifice too much energy or consume too much working
fluid. Another desired attribute is the ability to produce high
power output from a small, compact package, i.e. having high
energy-density. While the above qualities and benefits are needed
in actuation systems, the technology used dictates the limits and
compromises of each system with respect to providing all the
features. Generally, a system will provide the advantages of some,
but not all, desired features. No prior actuation system has been
able to operate on compressed air provided by a small
fuel-efficient internal combustion engine-compressor. To date
compressed air systems could not simultaneously provide rapid
response, low fuel consumption, low working fluid loss, and
significant output force. A significant problem of Brayton-cycle
machine is the continuous high temperature that quickly erodes
components.
[0006] Prior technologies include pneumatic (compressed air)
systems, hydraulic systems, and electromechanical systems.
[0007] The prior technologies are deficient in certain critical
functions. The pneumatic system except when very high pressures are
used is typically a poor performer in the areas of stiffness, of
providing high bandwidth, and of maintaining position accuracy. The
hydraulic system has a problem with high consumption of working
fluid while providing both large-displacement motion and high
force. The electromechanical systems are most common. These become
excessively large and complex because of heavy batteries if
designed to generate both a high force and rapid motion. Electrical
batteries are present in a large number of forms. For this
application, batteries would provide adequate performance for
approximately 20-30 minutes. They would then be recharged or
discarded. FIG. 1 is a prior art continuous-combustion gas turbine
known also as a Brayton-cycle gas turbine. A combustible fuel, such
as gasoline, is provided via input 10 to a burner 12 which ignites
the fuel by mixing it with compressed air from an air compressor 14
in manifold 13. After fuel ignition burning and mixing high
temperature gases are allowed to exit via nozzles 16. As is well
known nozzles provide areas where gas pressure is decreased and
velocity increased. After passing through nozzles 16 high velocity
gas turns a turbine wheel 18 which in turn drives a load via shaft
20. Spent gas is vented via exhaust 22.
[0008] A Brayton-cycle machine is thus built using a compressor to
feed air under pressure to an air transfer manifold 13. The bypass
air flow mixing and combustion chamber burning permits a constant
pressure heat addition. The addition of heat energy to the cycle at
a constant pressure is the unique feature that characterizes the
Brayton-cycle process. This process may include flow mixing between
bypass air and combustor outlet air. The expansion process uses
turbine 18 as the energy extractor. Exhaust 22 constitutes constant
pressure heat removal. Because of the desired constant high
temperature heat addition in manifold 13, the related components
burner 12, manifold 13, nozzles 16, and turbine wheel 18 quickly
erode.
SUMMARY OF THE INVENTION
[0009] The primary object of the present invention is an actuator
with efficient conversion of chemical (fuel) into mechanical energy
in the form of compressed air that generates a force to move
objects without high temperature erosion problems for working
components.
[0010] Another object of the invention is an actuator providing
precise movement.
[0011] Another object of the invention is an actuator with
large-displacement motion.
[0012] A further object of the invention is an actuator producing
rapid motion.
[0013] Yet another object of the invention is an actuator providing
conversion of energy from fuel into compressed air using an
integrated free-piston or piston-crank internal combustion
engine-air compressor.
[0014] A final object of the invention is to provide an actuator
with high-energy density that offers compact packaging and high
power output.
[0015] Other objects and advantages of the present invention will
become apparent from the following descriptions, taken in
connection with the accompanying drawings, wherein, by way of
illustration and example, an embodiment of the present invention is
disclosed.
[0016] The machine described is for generating actuation force with
rapid, precise, and large-displacement motion comprising: an
internal combustion engine-air compressor energy source, a
pneumatic working fluid, two high pressure burners, two control
valves, a reversible turbine, a speed-reducing transmission, a
ball-screw push-rod mechanism, an optical encoder and a control
system.
[0017] Like a Brayton-cycle machine it uses two high-pressure
burners coupled to a reversible-drive turbine and transmission to
generate large-displacements with precise positioning using a
ball-screw push rod.
[0018] Each of these relates to the present system; offering forms
of energy transfer based on working fluid or mechanical drive to
develop controlled forces. The present system emulates a hydraulic
actuator in that it is capable of producing large-displacement
motion and significant force. It relates to the pneumatic system in
that the working fluid is compressed air. It is similar to the
electro-mechanical actuator in that it uses a stiff output gear
train and ball-screw push rod to generate force.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a prior art Brayton-cycle shown in cross
section;
[0020] FIG. 2 is a schematic block diagram of the complete
system;
[0021] FIG. 3 is a schematic diagram illustrating operation of the
actuator;
[0022] FIG. 4 is a cutaway diagram illustrating operation of the
reversing turbine;
[0023] FIG. 5 is a side view of the reversing turbine;
[0024] FIG. 6 is a cutaway diagram illustrating operation of the
hot catalytic-bed reactor;
[0025] FIG. 7 is a cutaway schematic diagram of one embodiment of
internal combustion engine-air compressor; and
[0026] FIG. 8 is similar to FIG. 5 except an integrated free-piston
engine-air compressor is shown.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0027] Detailed descriptions of the preferred embodiment are
provided herein. It is to be understood, however, that the present
invention may be embodied in various forms. Therefore, specific
details disclosed herein are not to be interpreted as limiting, but
rather as a basis for the claims and as a representative basis for
teaching one skilled in the art to employ the present invention in
virtually any appropriately detailed system, structure or
manner.
[0028] Turning first to FIG. 2 there is shown a schematic block
diagram of the present invention for generating actuation force
with rapid, precise, and large-displacement motion. In the
preferred embodiment of the invention, system energy is provided by
a first power supply 24. Power supply 24 may be a small
internal-combustion engine 25 fed from a fuel tank 26. The fuel may
be gasoline or any other combustible fuel. Engine 25 in turn is
used to drive air compressor 27. Compressor 27 feeds compressed air
to storage tank 28 which provides a reserve of compressed air at a
predesired pressure. This portion of the system converts energy in
the form of fuel into a mechanical form by driving a compressor
that generates the compressed-air working fluid. It is
automatically operable, when required, by use of starter 29.
Starter 29 may be further controlled by a pressure-sensing switch
30 that senses the pressure of compressed air stored in
compressed-air storage tank 28. Compressed-air storage tank 28 is
charged with compressed air by air compressor 27 when compressor 27
is driven by engine 25 of power supply 24. Air intake means 31
feeds internal combustion engine 25 with air to sustain the
combustion process of engine 25. Air intake means 31 also feeds air
to air compressor 27 that feeds high-pressure air into the
compressed-air storage tank 28. Fuel supply 26 functions to store
and to passively feed fuel to both engine 25 and to actuator 40 as
needed and on-demand, as determined by the actions of engine 25 and
actuator 40. The functions of the power supply 24, and the
pneumatic power system 32 (which includes air compressor 27, and
compressed-air storage tank 28) are to combine to generate a supply
of high-pressure air to act as the working fluid to power actuator
40. Compressed air from air storage tank 28 is fed to two control
valves 60 and 70 within actuator 40. Control valves 60 and 70
receive direction from control operator 80 which may be an optical
encoder or any computer for issuing output signals based on
preselected sensor input, not shown. Manual human control may also
be used to decide instructions to be issued. Two preferred
embodiments of an integrated engine 25 and air-compressor 27 that
offer the functions of both power supply 24 and pneumatic power
system 32 within an integrated unit are further described in FIG.
6.
[0029] Actuator 40 provides bi-directional force and motion output
through push rod 41 that consists of a ball-screw mechanical arm.
Push rod 41 is driven by a rotation means 42. Rotation means 42 may
consist of the output of a 32:1 rotary speed-reducing transmission
coupled to a small high-speed (100 K rpm) reversing-turbine. The
push-pull action of push rod 41 depends on the ability to
reverse-drive a reversing turbine 50. This is accomplished by the
action of control valves 60 and 70 as well as innovative design of
the reversing turbine 50, to be described later in FIG. 4.
[0030] Reversing-turbine 50 receives power input from pneumatic
power system 32 (and elements 60, 70, 61, 71) that, working
together, control and deliver a supply of hot, high-pressure air.
As in a Brayton-cycle machine, the air, supplied from the
compressed-air tank 28, is fed to reversing turbine 50 through
either one of two hot, high-pressure burners known as the push
reactor burner 61 and the pull reactor burner 71, to be described
in more detail later in FIG. 6. These burners receive high-pressure
air from air storage tank 28 under the control of valves 60 and 70.
Valves 60 and 70 consist of electrically-controlled pilot valves
that switch high-pressure air under the control of small electrical
currents supplied by the control operator system 80 based upon
operator commands. Burners 61 and 71 function to heat the
high-pressure input air from tank 21 to a temperature of about
1800.degree. F. with the addition of fuel from supply 26, using an
electrical power ignition system 90, and under the action of a
catalyst-bed lean-burn combustion process within each burner. The
functions of burners 61 and 71 are controlled separately, by the
flow of air from control valves 60 or 70, to determine which burner
will supply power to the reversing turbine 50. Burners 61 and 71
add heat at constant pressure. The energy content may be doubled or
more with no significant change of pressure. By design, the choice
of burner 61 or 71 also dictates the direction of rotation of
turbine 50. This in turn determines the direction of motion (to
push or to pull) that push rod 41 will produce; thereby meeting the
needs and the functional requirements placed upon actuator system
40 by operator control system 80.
[0031] Finally, FIG. 2 shows the electric power system 90 which has
an alternator 91 driven by engine 25. Alternator 91 charges a
battery 92 which provides electrical power to actuator 40 and
provides a utility power output 93 for other systems not shown. A
further function of the electric power system 90 is to supply
various sensors (such as pressure switches, optical encoders) and
the engine starter 29 with electric power to support those
functions. A final function of the electric power system 90 is to
provide utility power output to support miscellaneous user needs;
such as to provide lighting or to supply power tools with
energy.
[0032] In accordance with the present invention, FIG. 3 shows a
more detailed schematic diagram illustrating operation of the
actuator 40 portion of the invention. Actuator 40 produces
bi-directional force and motion output through push rod 41, a
ball-screw mechanical arm. Push rod 41 is driven by a
rotationally-operable ball bearing screw-jack means 42 which
couples into the output of a 32:1 rotary speed reduction
transmission means 43. Transmission means 43 input is driven by a
reversing-turbine 50 which may be a small high-speed reversing
turbine, for example turbine speed may be 100 K rpm. The push-pull
bi-directional action of push rod 41 depends on the ability to
reverse-drive turbine 50. This function is accomplished by the
action of control valves 60 and 70, as well as the reversing
turbine 50 design described in FIG. 4.
[0033] Reversing-turbine 50 receives power input from hot,
high-pressure air derived from pneumatic power system 32.
Pressurized air is fed to turbine 50 through one of two
high-pressure reactor-burners, the push reactor-burner 61 or the
pull reactor-burner 71. These reactor-burners receive high-pressure
air from air storage tank 28 under control of valves 60 and 70.
Valves 60 and 70 may consist of electrically controlled pilot
valves operable under control of small electrical currents supplied
by control operator system 80. The reactor-burners 61 and 71 react
a mixture of fuel and air, provided by fuel injector/mixers 62 and
72, to heat pressurized input air for example of 150 psi pressure,
from tank 28 to a temperature of approximately 1800 F. This
function is accomplished under the action of a catalyst-bed
lean-burn combustion process within each reactor-burner. Burners 61
and 71 are controlled separately to determine which burner will
supply heated air to reversing turbine 50. The choice of
reactor-burner 61 or 71 dictates the direction of rotation of
turbine 50. This determines the direction of motion, that is to
push or to pull, that push rod 41 produces; thereby meeting the
needs placed on actuator system 40 by operator control system
80.
[0034] To provide for actuator system 40 feedback control, an
optical-encoder 44 is integrated within reversing turbine 50. This
consists first of holes 56, shown in FIG. 5, through the turbine 50
web or gear web as shown in FIG. 3. As reversing turbine 50
rotates; each revolution, the holes (each in turn and not at the
same time) come into alignment with a first beam of light 46 and a
second light sensor 47. Light 46 and sensor 47 as a design choice
may scan via holes 56 in turbine 50. The light sensor 47 receives
light emitting through the hole opening, as alignment occurs, and
responds by producing an electrical signal. The frequency and
count-number of signals generated by light sensor 47 are fed-back
to the operator control system computer 80 and used to determine
the speed and position of push-rod 41 and thereby precisely-control
the motion and position.
[0035] In accordance with an important feature of the present
invention, there is shown in FIG. 4 a schematic diagram
illustrating the operation of the reversing turbine 50 portion of
the invention. Reversing turbine 50 consists of a single rotor 51
that locates around the outer perimeter of the rotor 51 two sets of
oppositely-directed radial-inflow turbine blades; the push blade
set 52, and the pull blade set 53. The multiplicity of blades
contained in blade set 52 and 53 are designed to cause reversing
turbine 50 to rotate in a preferred direction; either clockwise or
counterclockwise. The direction of rotation of reversing turbine 50
is caused by the action of hot, high-pressure air impinging onto
either blade set 52 or blade set 53 separately, and not at the same
time. By the novel design of this turbine rotor, there are two
separate nozzle and gas flow control system interfaces. These
include nozzle 54 and hot-air source 61 for push-functions; and
nozzle 55 and hot air source 71 for pull-functions, both meeting
with the same rotor 51 but communicating with either blade set 52
(for push functions), or blade set 53 (for pull functions).
Furthermore, these nozzles, 54 and 55, are independently operable,
without interference from one to the other. This is accomplished by
locating the two radial-inflow blade sets 52 and 53 at the same
diameter of the turbine rotor 51, but mechanically separated and
situated on opposite sides thereof. The opposed-sets of identical,
but having reversed curve-profiles, blades enables the turbine
direction of rotation to be controlled simply by selecting which
nozzle 54 or 55 is fed by hot, high-pressure air. Because the
turbine rotor 51 may be very small for example 1.0" diameter, with
very high speed for example 100 K rpm, the time required to reverse
the turbine is very short--on the order of 0.01 seconds for the
example above--yet the power output can be very large--on the order
of 2100 ft-lb./sec. This power is usefully taken advantage of
through the function of the gear-reduction transmission 43 that
makes the high-speed rotary turbine power available to the
ball-screw push-pull actuator arm also known as push rod 41. The
resultant gear reduction provides an actuator push rod 41 force
output on the order of 3800 lbs. force and enables an actuator arm
41 maximum linear speed on the order of 6.5 in/sec. For the above
example the gear reduction ratio is 32:1. This may be higher or
lower as a matter of design choice.
[0036] FIG. 5 is a side view of FIG. 4. Radial blades 52 form a
ring around the turbine wheel. When hot gas is directed on radial
blades 52 they spin the wheel counterclockwise as shown in FIG. 5.
Radial blades 53 also form a ring around the turbine wheel but on
the far side and thus are shown by dotted lines. When hot gas is
directed on them, they will spin the wheel in a clockwise
direction.
[0037] To accomplish another important function of the invention,
there is shown in FIG. 6 a schematic diagram illustrating the
operation of the hot catalytic-bed reactor-burner portion of the
invention. Each burner-reactor 61 and 71 is identical and is
designed to react high-pressure air fed from storage tank means 28
with fuel supplied from storage source 29 as shown in FIG. 3. The
fuel and high-pressure air are mixed in fuel injector mixing means
62 and 72 in advance of being supplied to each reactor-burner tank
61 and 71. Each reactor-burner tank 61 and 71 contains a catalytic
bed 63 shown in FIG. 6 and a hot-wire glow plug means 64 fed by
power from electrical power 90 and controlled by operator control
system 80. The beneficial function of catalytic bed 63 is to react
a lean-mixture of high-pressure air with fuel, burning this mixture
quickly by a very short combustion-reaction time constant. This
provides efficient, clean, and complete combustion; all within the
confines of a short burner tank. It also provides the ability to
rapidly start the combustion process, once catalytic bed 63 is
heated to normal operating temperature. Finally, the
high-temperature air output, for example 1800.degree. F. from
burner 61 promotes more-efficient energy-extraction from the
turbine output stage of the actuator system 40.
[0038] To accomplish a further important function of the invention,
there is shown in FIG. 7 a schematic diagram illustrating the
operation of the integrated internal-combustion engine 25 and air
compressor 27 portions of the invention.
[0039] FIG. 7 shows a hybrid piston-crank internal combustion
engine 72 and air compressor 73 as one possible embodiment. In this
embodiment, a two-cylinder machine is illustrated having a common
crankshaft 74 and two piston-cylinders 75 configured in a vee
arrangement. One cylinder and piston forms the internal-combustion
engine 72 (in either a two-cycle or four-cycle configuration) that
is operable to drive the opposite slaved piston and cylinder, the
air compressor portion of the engine-compressor assembly. The two
machines are joined by the common crankshaft 74 to form a hybrid
engine-air compressor that is both compact and operable to convert
fuel-based chemical energy into mechanical energy in the form of
compressed air. A common air storage tank 28 is also shown that
receives compressed air for accumulation and storage.
[0040] An alternate embodiment to FIG. 7 is FIG. 8 which has a
hybrid free-piston internal combustion engine 111 and air
compressors 130. In this embodiment a two-piston machine is
illustrated having a common combustion chamber 116 and two
double-duty pistons 117 configured in a linear cylinder 118, known
as an opposed-piston inward-firing free-piston gasifier. Each
double-duty piston 117 forms both an internal-combustion engine 111
(associated with the inner small-diameter piston) and an air
compressor 130 (associated with the outer large-diameter piston).
The opposite pistons and cylinders form two internal combustion
engines 111 and air compressors 130, each the mirror image of the
other. Both machines are joined within a common cylinder 118 and by
a common combustion chamber 116 to form a hybrid free-piston
engine-air compressor (well known in prior art as a free-piston
gasifier) that is both compact and operable to convert fuel-based
chemical energy into mechanical energy in the form of compressed
air. A common air storage tank 121 which has a plurality of intake
ports 119 is also shown that receives compressed exhaust air via
intake ports 119 for accumulation and storage. The air compressor
actually functions as a supercharger for the combustion chamber.
That is, the compressed air with added fuel is manifolded into the
combustion chamber prior to the motion of the pistons to the center
of the engine. Upon ignition, the expanding gas at first propels
pistons 111 outward, then exhaust at high pressure into manifold
137. Pistons 111 are slowed and stopped by air in bounce chamber
132, one for each piston 111. As the air in bounce chambers 132 is
compressed it slows, stops, and then pushes pistons 111 back
towards each other. As bounce chambers 132 are still being
compressed new intake air is brought into compressor 130 via air
intake valves 113. When pistons 111 are relatively far apart air
from storage tank 121 enters engine 116. As pistons 111 approach
each other the air intake is sealed off and storage tank 121 is
refilled via air intakes 119. This process produces high pressure
output air that may be heated to a temperature of approximately
800.degree. F. This improves overall Brayton-cycle efficiency and
reduces the requirement for heat addition provided by catalytic
burners 61 and 71 shown previously while at the same time providing
a more compact engine and compressor arrangement. The combination
and method of using a free-piston engine and air compressor (i.e.
any form of free-piston gasifier) within an actuation system will
provide for many new applications.
[0041] As an example, the uniquely combined elements described
above provide an actuator system 40 and a method that offers the
beneficial features of:
[0042] Generating significant force to move objects; on the order
of 3800 lbf.
[0043] Providing precise movement with typical position accuracy of
0.005".
[0044] Producing large-displacement, linear motion on the order of
6" stroke.
[0045] Producing rapid motion on the order of 6.5"/sec linear
output motion with 15-20 Hz Bandwidth response characteristic and
25 Hz Bandwidth open-loop response.
[0046] Having an efficient energy-conversion from power source 10
to push rod 41 on the order of 9% overall thermodynamic efficiency
with potential for further improvement to 25%.
[0047] While the invention has been described in connection with a
preferred embodiment, it is not intended to limit the scope of the
invention to the particular form set forth, but on the contrary, it
is intended to cover such alternatives, modifications, and
equivalents as may be included within the spirit and scope of the
invention as defined by the appended claims.
* * * * *