Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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VARIABLE COMPRESSION PISTON ASSEMBLY
Background of the Invention
The invention relates to a variable compression
piston assembly, and to an engine that has double ended
pistons connected to a universal joint for converting
linear motion of the pistons to rotary motion.
Most piston driven engines have pistons that are
attached to offset portions of a crankshaft such that as
the pistons are moved in a reciprocal direction
transverse to the axis of the crankshaft, the crankshaft
will rotate.
U.S. Patent 5,535,709, defines an engine with a
double ended piston that is attached to a crankshaft with
an off set portion. A lever attached between the piston
and the crankshaft is restrained in a fulcrum regulator
to provide the rotating motion to the crankshaft.
U.S. Patent 4,011,842, defines a four cylinder
piston engine that utilizes two double ended pistons
connected to a T-shaped T-shaped connecting member that
causes a crankshaft to rotate. The T-shaped connecting
member is attached at each of the T-cross arm to a double
ended piston. A centrally located point on the T-cross
arm is rotatably attached to a fixed point, and the
bottom of the T is rotatably attached to a crank pin
which is connected to the crankshaft by a crankthrow
which includes a counter weight.
in each of the above examples, double ended
pistons are used that drive a crankshaft that has an axis
transverse to the axis of the pistons.
Summary of the Invention
According to the invention, a variable compression
piston assembly includes a plurality of pistons, a
transition arm coupled to each of the pistons, and a
rotating member coupled to a drive member of the
transition arm and configured for sliding movement along
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an axis of the drive member. The movement of the
rotating member relative to the drive member changes the
compression ratio of the piston assembly.
Embodiments of this aspect of the invention may
include one or more of the following features.
The pistons are double ended pistons. The
transition arm is coupled to each of the double ended
pistons at approximately a center of each piston.
Movement of the rotating member relative to the
transition arm changes the compression ratio and
displacement of each double ended piston.
The assembly includes two pistons, and the axis of
rotation of the rotating member and the axes of the two
pistons lie on a common plane. The rotating member is a
flywheel. A control rod is operationally connected to
the flywheel such that actuation of the control rod
provides linear movement of the flywheel relative to the
transition arm.
In certain illustrated embodiments, the rotating
member is configured to be positionable in a zero-stroke
position in which rotation of the rotating member occurs
without corresponding movement of the pistons. The
rotating member comprises a pivot member pivotally
mounted to a control member. Actuation of the control
member results in movement of the pivot member to vary
the compression ratio.
The pistons can be arranged with their axes
parallel or non-parallel.
Drive pins connect the transition arm to the
pistons. The drive member extends into an opening in the
rotatable member adjacent to the periphery of the
rotatable member. The drive member extends into a pivot
pin located in the rotatable member. A main drive shaft
is connected to the rotatable member. The drive shaft
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axis is parallel to the axis of each pisto.^.. A universal
joint connects the transition arm to a support.
At least one of the pl-urality of pistons :las an
output pump piston for driving a pump.
According to another aspect of the invention, a
method for varying the compression ratio of a piston
assembly includes providing a plurality of pistons, a
transition arm coupled to each of the pistons, and a
rotating member coupled to a drive member of the
transition arm and configured for sliding movement
relative to an axis of the drive member. The rotating
member is moved relative to the drive member to change
the compression ratio of the piston assembly.
According to another aspect of the invention, a
method of increasing the efficiency of a piston assembly
includes providing a plurality of double ended pistons, a
transition arm coupled to each of the double ended
pistons at approximately a center of each of the pistons,
and a rotating member coupled to a drive member of the
transition arm and configured for sliding movement
relative to the drive member. The rotating member is
moved relative to the drive member to change the
compression ratio and displacement of the double ended
piston assembly.
_. . . ., ~ :.~ ... ,..u.,_. .........~ .~. . , . ..., .
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In accordance with another aspect of the
invention, there is provided a piston assembly, comprising:
at least two pistons having axes lying on a common plane, a
piston rod of each piston being configured for linear
motion, a transition arm coupled to each of the pistons and
including at least two drive arms, each drive arm defining a
drive arm axis, and a universal joint connecting the
transition arm to a support by two pins to permit pivoting
motion about two axes, wherein a center of the universal
joint lies other than on the common plane, and at least two
joints, each joint coupling the transition arm to a
respective one of the pistons and providing four degrees of
freedom between the transition arm and the respective
piston, the four degrees of freedom being a first degree of
freedom that includes rotation about the drive arm axis, a
second degree of freedom that includes sliding along the
drive arm axis, a third degree of freedom that includes
pivoting about an axis perpendicular to the drive arm axis,
and a fourth degree of freedom that includes sliding in the
direction of the perpendicular axis, wherein each joint
comprises an outer member coupled to the piston and an inner
member mounted within the outer member such that the inner
member slides along the perpendicular axis to provide the
fourth degree of freedom.
In accordance with another aspect of the
invention, there is provided a piston assembly, comprising:
at least two pistons having axes lying on a common plane, a
piston rod of each piston being configured for linear
motion, a transition arm coupled to each of the pistons, and
a universal joint connecting the transition arm to a support
by two pins to permit pivoting motion about two axes,
wherein a center of the universal joint lies other than on
the common plane, and a joint for coupling the transition
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arm to a respective one of the pistons, the joint providing
four degrees of freedom between the transition arm and the
respective piston.
In accordance with another aspect of the
invention, there is provided a piston assembly, comprising:
a plurality of pistons, a piston rod of each piston being
configured for linear motion, a transition arm, a plurality
of drive members, each drive member coupling the transition
arm to a respective one of the pistons, and a universal
joint connecting the transition arm to a support by two pins
to permit pivoting motion about two axes, wherein each drive
member is capable of movement relative to the universal
joint, and a plurality of joints, each joint for coupling a
respective drive member to a respective one of the pistons,
wherein at least one of the joints provides degrees of
freedom in four directions between the drive member and the
respective piston.
In accordance with another aspect of the
invention, there is provided an assembly, comprising: at
least two double-ended members, a first of the double-ended
members having first and second elements configured for
linear motion along a first axis, and a second of the
double-ended members having first and second elements
configured for linear motion along a second axis, the first
and second axes lying on a common plane, a transition arm
coupled to each of the double-ended members, wherein an axis
of rotation of a rotating member coupled to the transition
arm lies other than on the common plane, the axis of the
first of the double-ended members and the axis of the
rotating member lie on a first plane, and the axis of the
second of the double-ended members and the axis of the
rotating member lie on a second plane which intersects the
first plane at about a 90-degree angle, at least two joints,
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each joint for coupling the transition arm to a respective
one of the double-ended members, each joint providing four
degrees of freedom between the transition arm and the
respective double-ended member, and a universal joint
connecting the transition arm to a support by two pins to
permit pivoting motion about two axes.
In accordance with another aspect of the
invention, there is provided a piston assembly, comprising:
at least two pistons having axes lying on a common plane, a
piston rod of each piston being configured for linear
motion, wherein at least one of the pistons comprises a
double-ended piston, a transition arm coupled to each of the
pistons, and a universal joint connecting the transition arm
to a support by two pins to permit pivoting motion about two
axes, wherein a center of the universal joint lies other
than on the common plane.
In accordance with another aspect of the
invention, there is provided a piston assembly, comprising:
a plurality of pistons, a piston rod of each piston being
configured for linear motion, wherein at least one of the
pistons comprises a double-ended piston, a transition arm, a
plurality of drive members, each drive member coupling the
transition arm to a respective one of the pistons, and a
universal joint connecting the transition arm to a support
by two pins to permit pivoting motion about two axes,
wherein each drive member is capable of movement relative to
the universal joint.
Brief Description of the Drawings
FIGS. 1 and 2 are side view of a simplified
illustration of a four cylinder engine of the present
invention;
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FIGS. 3, 4, 5 and 6 are top views of the engine of
FIG. 1 showing the pistons and flywheel in four different
positions;
FIG. 7 is a top view, partially in cross-section
of an eight cylinder engine of the present invention;
FIG. 8 is a side view in cross-section of the
engine of FIG. 7;
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FIG. 9 is a right end view of FIG. 7;
FIG. 10 is a side view of FIG. 7;
FIG. 11 is a left end view of FIG. 7;
FIG. 12 is a partial top view of the engine of
FIG. 7 showing the pistons, drive member and flywheel in
a high compression position;
FIG. 13 is a partial top view of the engine in
FIG. 7 showing the pistons, drive member and flywheel in
a low compression position;
FIG. 14 is a top view of a piston;
FIG. 15 is a side view of a piston showing the
drive member in two positions;
FIG. 16 shows the bearing interface of the drive
member and the piston;
FIG. 17 is an air driven engine/pump embodiment;
FIG. 18 illustrates the air valve in a first
position;
FIGS. 18a, 18b and 18c are cross-sectional view of
three cross-sections of the air valve shown in FIG. 18;
FIG. 19 illustrates the air valve in a second
position;
FIGS. 19a, 19b and 19c are cross-sectional view of
three cross-sections for the air valve shown in FIG. 19;
FIG. 20 shows an embodiment with slanted
cylinders;
FIG. 21 shows an embodiment with single ended
pistons;
FIG. 22 is a top view of a two cylinder, double
ended piston assembly;
FIG. 23 is a top view of one of the double ended
pistons of the assembly of FIG. 22;
FIG. 23a is a side view of the double ended piston
of FIG. 23, taken along lines 23A, 23A;
FIG. 24 is a top view of a transition arm and
universal joint of the piston assembly of FIG. 22;
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FIG. 24a is a side view of the transition arm and
universal joint of FIG. 24, taken along lines 24a, 24a;
FIG. 25 is a perspective view of a drive arm
connected to the transition arm of the piston assembly of
FIG. 22;
FIG. 25a is an end view of a rotatable member of
the piston assembly of FIG. 22, taken along lines 25a,
25a of FIG. 22, and showing the connection of the drive
arm to the rotatable member;
FIG. 25b is a side view of the rotatable member,
taken along lines 25b, 25b of FIG. 25a;
FIG. 26 is a cross-sectional, top view of the
piston assembly of FIG. 22;
FIG. 27 is an end view of the transition arm,
taken along lines 27, 27 of FIG. 24;
FIG. 27a is a cross-sectional view of a drive pin
of the piston assembly of FIG. 22;
FIGS. 28-28b are top, rear, and side views,
respectively, of the piston assembly of FIG. 22;
FIG. 28c is a top view of an auxiliary shaft of
the piston assembly of FIG. 22;
FIG. 29 is a cross-sectional side view of a zero-
stroke coupling;
FIG. 29a is an exploded view of the zero-stroke
coupling of FIG. 29;
FIG. 30 is a graph showing the figure 8 motion of
a non-flat piston assembly;
FIG. 31 shows a reinforced drive pin;
FIG. 32 is a top view of a four cylinder engine
for directly applying combustion pressures to pump
pistons; and
FIG. 32a is an end view of the four cylinder
engine, taken along lines 32a, 32a of FIG. 32.
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Description of the Preferred Embodiments
FIG. 1 is a pictorial representation of a four
piston engine 10 of the present invention. Engine 10 has
two cylinders 11 (FIG. 3) and 12. Each cylinder 11 and
12 house a double ended piston. Each double ended piston
is connected to transition arm 13 which is connected to
flywheel 15 by shaft 14. Transition arm 13 is connected
to support 19 by a universal joint mechanism, including
shaft 18, which allows transition arm 13 to move up an
down and shaft 17 which allows transition arm 13 to move
side to side. FIG. 1 shows flywheel 15 in a position
shaft 14 at the top of wheel 15.
FIG. 2 shows engine 10 with flywheel 15 rotated so
that shaft 14 is at the bottom of flywheel 15.
Transition arm 13 has pivoted downward on shaft 18.
FIGS. 3-6 show a top view of the pictorial
representation, showing thetransition arm 13 in four
positions and shaft moving flywheel 15 in 90 increments.
FIG. 3 shows flywheel 15 with shaft 14 in the position as
illustrated in FIG. 3a. When piston 1 fires and moves
toward the middle of cylinder 11, transition arm 13 will
pivot on universal joint 16 rotating flywheel 15 to the
position shown in FIG. 2. Shaft 14 will be in the
position shown in FIG 4a. When piston 4 is fired,
transition arm 13 will move to the position shown in FIG.
5. Flywheel 15 and shaft 14 will be in the position
shown in FIG 5a. Next piston 2 will fire and transition
arm 13 will be moved to the position shown in FIG. 6.
Flywheel 15 and shaft 14 will be in the position shown in
FIG. 6a. When piston 3 is fired, transition arm 13 and
flywheel 15 will return to the original position that
shown in FIGS. 3 and 3a.
When the pistons fire, transition arm will be
moved back and forth with the movement of the pistons.
Since transition arm 13 is connected to universal joint
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16 and to flywheel 15 through shaft 14, flywheel 15
rotates translating the linear motion of the pistons to a
rotational motion.
FIG. 7 shows (in partial cross-section) a top view
of an embodiment of a four double piston, eight cylinder
engine 30 according to the present invention. There are
actually only four cylinders, but with a double piston in
each cylinder, the engine is equivalent to a eight
cylinder engine. Two cylinders 31 and 46 are shown.
Cylinder 31 has double ended piston 32, 33 with piston
rings 32a and 33a, respectively. Pistons 32, 33 are
connected to a transition arm 60 (FIG. 8) by piston arm
54a extending into opening 55a in piston 32, 33 and
sleeve bearing 55. Similarly piston 47, 49, in cylinder
46 is connected by piston arm 54b to transition arm 60.
Each end of cylinder 31 has inlet and outlet
valves controlled by a rocker arms and a spark plug.
Piston end 32 has rocker arms 35a and 35b and spark plug
44, and piston end 33 has rocker arms 34a and 34b, and
spark plug 41. Each piston has associated with it a set
of valves, rocker arms and a spark plug. Timing for
firing the spark plugs and opening and closing the inlet
and exhaust values is controlled by a timing belt 51
which is connected to pulley 50a. Pulley 50a is attached
to a gear 64 by shaft 63 (FIG. 8) turned by output shaft
53 powered by flywheel 69. Belt 50a also turns pulley
50b and gear 39 connected to distributor 38. Gear 39
also turns gear 40. Gears 39 and 40 are attached to cam
shaft 75 (FIG. 8) which in turn activate push rods that
are attached to the rocker arms 34, 35 and other rocker
arms not illustrated.
Exhaust manifolds 48 and 56 as shown attached to
cylinders 46 and 31 respectively. Each exhaust manifold
is attached to four exhaust ports.
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FIG. 8 is a side view of engine 30, with one side
removed, and taken through section 8-8 of FIG. 7.
Transitions arm 60 is mounted on support 70 by pin 72
which allows transition arm to move up and down (as
viewed in FIG. 8) and pin 71 which allows transition arm
60 to move from side to side. Since transition arm 60
can move up and down while moving side to side, then
shaft 61 can drive flywheel 69 in a circular path. The
four connecting piston arms (piston arms 54b and 54d
shown in FIG. 8) are driven by the four double end
pistons in an oscillator motion around pin 71. The end
of shaft 61 in flywheel 69 causes transition arm to move
up and down as the connection arms move back and forth.
Flywheel 69 has gear teeth 69a around one side which may
be used for turning the flywheel with a starter motor 100
(FIG. 11) to start the engine.
The rotation of flywheel 69 and drive shaft 68
connected thereto, turns gear 65 which in turn turns
gears 64 and 66. Gear 64 is attached to shaft 63 which
turns pulley 50a. Pulley 50a is attached to belt 51.
Belt 51 turns pulley 50b and gears 39 and 40 (FIG. 7).
Cam shaft 75 has cams 88-91 on one end and cams 84-87 on
the other end. Cams 88 and 90 actuate push rods 76 and
77, respectively. Cams 89 and 91 actuate push rods 93
and 94, respectively. Cams 84 and 86 actuate push rods
95 and 96, respectively, and cams 85 and 87 actuate push
rods 78 and 79, respectively. Push rods 77, 76, 93, 94,
95, 96 and 78, 79 are for opening and closing the intake
and exhaust valves of the cylinders above the pistons.
The left side of the engine, which has been cutaway,
contains an identical, but opposite valve drive
mechanism.
Gear 66 turned by gear 65 on drive shaft 68 turns
pump 67, which may be, for example, a water pump used in
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the engine cooling system (not illustrated), or an oil
pump.
FIG. 9 is a rear view of engine 30 showing the
relative positions of the cylinders and double ended
pistons. Piston 32, 33 is shown in dashed lines with
valves 35c and 35d located under lifter arms 35a and 35b,
respectively. Belt 51 and pulley 50b are shown under
distributor 38. Transition arm 60 and two, 54c and 54d,
of the four piston arms 54a, 54b, 54c and 54d are shown
in the pistons 32-33, 32a-33a, 47-49 and 47a-49a.
FIG. 10 is a side view of engine 30 showing the
exhaust manifold 56, intake manifold 56a and carburetor
56c. Pulleys 50a and 50b with timing belt 51 are also
shown.
FIG. 11 is a front end view of engine 30 showing
the relative positions of the cylinders and double ended
pistons 32-33, 32a-33a, 47-49 and 47a-49a with the four
piston arms 54a, 54b, 54c and 54d positioned in the
pistons. Pump 67 is shown below shaft 53, and pulley 50a
and timing belt 51 are shown at the top of engine 30.
Starter 100 is shown with gear 101 engaging the gear
teeth 69a on flywheel 69.
A feature of the invention is that the compression
ratio for the engine can be changed while the engine is
running. The end of arm 61 mounted in flywheel 69
travels in a circle at the point where arm 61 enters
flywheel 69. Referring to FIG. 13, the end of arm 61 is
in a sleeve bearing ball bushing assembly 81. The stroke
of the pistons is controlled by arm 61. Arm 61 forms an
angle, for example about 150, with shaft 53. By moving
flywheel 69 on shaft 53 to the right or left, as viewed
in FIG. 13, the angle of arm 61 can be changed, changing
the stroke of the pistons, changing the compression
ratio. The position of flywheel 69 is changed by turning
nut 104 on threads 105. Nut 104 is keyed to shaft 53 by
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thrust bearing 106a held in place by ring 106b. In the
position shown in FIG. 12, flywheel 69 has been moved to
the right, extending the stroke of the pistons.
FIG. 12 shows flywheel moved to the right
increasing the stroke of the pistons, providing a higher
compression ratio. Nut 105 has been screwed to the
right, moving shaft 53 and flywheel 69 to the right. Arm
61 extends further into bushing assembly 80 and out the
back of flywheel 69.
FIG. 13 shows flywheel moved to the left reducing
the stroke of the pistons, providing a lower compression
ratio. Nut 105 has been screwed to the left, moving
shaft 53 and flywheel 69 to the left. Arm 61 extends
less into bushing assembly 80.
The piston arms on the transition arm are inserted
into sleeve bearings in a bushing in piston. FIG. 14
shows a double piston 110 having piston rings 111 on one
end of the double piston and piston rings 112 on the
other end of the double piston. A slot 113 is in the
side of the piston. The location the sleeve bearing is
shown at 114.
FIG. 15 shows a piston arm 116 extending into
piston 110 through slot 116 into sleeve bearing 117 in
bushing 115. Piston arm 116 is shown in a second
position at 116a. The two pistons arms 116 and 116a show
the movement limits of piston arm 116 during operation of
the engine.
FIG. 16 shows piston arm 116 in sleeve bearing
117. Sleeve bearing 117 is in pivot pin 115. Piston arm
116 can freely rotate in sleeve bearing 117 and the
assembly of piston arm 116, Sleeve bearing 117 and pivot
pin 115 and sleeve bearings 118a and 118b rotate in
piston 110, and piston arm 116 can moved axially with the
axis of sleeve bearing 117 to allow for the linear motion
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of double ended piston 110, and the motion of a
transition arm to which piston arm 116 is attached.
FIG. 17 shows how the four cylinder engine 10 in
FIG. 1 may be configured as an air motor using a four way
rotary valve 123 on the output shaft 122. Each of
cylinders 1, 2, 3 and 4 are connected by hoses 131. 132,
133, and 144, respectively, to rotary valve 123. Air
inlet port 124 is used to supply air to run engine 120.
Air is sequentially supplied to each of the pistons la,
2a, 3a dn 4a, to move the pistons back and forth in the
cylinders. Air is exhausted from the cylinders out
exhaust port 136. Transition arm 126, attached to the
pistons by connecting pins 127 and 128 are moved as
described with references to FIGS. 1-6 to turn flywheel
129 and output shaft 22.
FIG. 18 is a cross-sectional view of rotary valve
123 in the position when pressurized air or gas is being
applied to cylinder 1 through inlet port 124, annular
channel 125, channel 126, channel 130, and air hose 131.
Rotary valve 123 is made up of a plurality of channels in
housing 123 and output shaft 122. The pressurized air
entering cylinder 1 causes piston la, 3a to move to the
right (as viewed in FIG. 18) . Exhaust air is forced out
of cylinder 3 through line 133 into chamber 134, through
passageway 135 and out exhaust outlet 136.
FIGS. 18a, 18b and 18c are cross-sectional view of
valve 23 showing the air passages of the valves at three
positions along valve 23 when positioned as shown in FIG.
18.
FIG. 19 shows rotary valve 123 rotated 180 when
pressurized air is applied to cylinder 3, reversing the
direction of piston la,3a. Pressurized air is applied to
inlet port 124, through annular chamber 125, passage way
126, chamber 134 and air line 133 to cylinder 3. This in
turn causes air in cylinder 1 to be exhausted through
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line 131, chamber 130, line 135, annular chamber 137 and
out exhaust port 136. Shaft 122 will have rotated 3600
turning counter clockwise when piston la,3a complete it
stroke to the left.
Only piston la,3a have been illustrated to show
the operation of the air engine and valve 123 relative to
the piston motion. The operation of piston 2a,4a is
identical in function except that its 360 cycle starts
at 90 shaft rotation and reverses at 2700 and completes
its cycle back at 90 . A power stroke occurs at every
900 of rotation.
FIGS. 19a, 19b and 19c are cross-sectional views
of valve 123 showing the air passages of the valves at
three positions along valve 123 when positioned as shown
in FIG. 19.
The principle of operation which operates the air
engine of FIG. 17 can be reversed, and engine 120 of FIG.
17 can be used as an air or gas compressor or pump. By
rotating engine 10 clockwise by applying rotary power to
shaft 122, exhaust port 136 will draw in air into the
cylinders and port 124 will supply air which may be used
to drive, for example air tool, or be stored in an air
tank.
In the above embodiments, the cylinders have been
illustrated as being parallel to each other. However,
the cylinders need not be parallel. FIG. 20 shows an
embodiment similar to the embodiment of FIG. 1-6, with
cylinders 150 and 151 not parallel to each other.
Universal joint 160 permits the piston arms 152 and 153
to be at an angle other than 90 to the drive arm 154.
Even with the cylinders not parallel to each other the
engines are functionally the same.
Still another modification may be made to the
engine 10 of FIGS. 1-6. This embodiment, pictorially
shown in FIG. 21, may have single ended pistons. Piston
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la and 2a are connected to universal joint 170 by drive
arms 171 and 172, and to flywheel 173 by drive arm 174.
The basic difference is the number of strokes of pistons
la and 2a to rotate flywheel 173 360 .
Referring to FIG. 22, a two cylinder piston
assembly 300 includes cylinders 302, 304, each housing a
variable stroke, double ended piston 306, 308,
respectively. Piston assembly 300 provides the same
number of power strokes per revolution as a conventional
four cylinder engine. Each double ended piston 306, 308
is connected to a transition arm 310 by a drive pin 312,
314, respectively. Transition arm 310 is mounted to a
support 316 by, e.g., a universal joint 318 (U-joint),
constant velocity joint, or spherical bearing. A drive
arm 320 extending from transition arm 310 is connected to
a rotatable member, e.g., flywheel 322.
Transition arm 310 transmits linear motion of
pistons 306, 308 to rotary motion of flywheel 322. The
axis, A, of flywheel 322 is parallel to the axes, B and
C, of pistons 306, 308 (though axis, A, could be off-axis
as shown in FIG. 20) to form an axial or barrel type
engine, pump, or compressor. U-joint 318 is centered on
axis, A. As shown in FIG. 28a, pistons 306, 308 are 180
apart with axes A, B and C lying along a common plane, D,
to form a flat piston assembly.
Referring to FIGS. 22 and 23, cylinders 302, 304
each include left and right cylinder halves 301a, 301b
mounted to the assembly case structure 303. Double ended
pistons 306, 308 each include two pistons 330 and 332,
330a and 332a, respectively, joined by a central joint
334, 334a, respectively. The pistons are shown having
equal length, though other lengths are contemplated. For
example, joint 334 can be off-center such that piston 330
is longer than piston 332. As the pistons are fired in
sequence 330a, 332, 330, 332a, from the position shown in
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FIG. 22, flywheel 322 is rotated in a clockwise
direction, as viewed in the direction of arrow 333.
Piston assembly 300 is a four stroke cycle engine, i.e.,
each piston fires once in two revolutions of flywheel
322.
As the pistons move back and forth, drive pins
312, 314 must be free to rotate about their common axis,
E, (arrow 305), slide along axis, E, (arrow 307) as the
radial distance to the center line, B, of the piston
changes with the angle of swing, a, of transition arm 310
(approximately f150 swing), and pivot about centers, F,
(arrow 309). Joint 334 is constructed to provide this
freedom of motion.
Joint 334 defines a slot 340 (FIG. 23a) for
receiving drive pin 312, and a hole 336 perpendicular to
slot 340 housing a sleeve bearing 338. A cylinder 341 is
positioned within sleeve bearing 338 for rotation within
the sleeve bearing. Sleeve bearing 338 defines a side
slot 342 shaped like slot 340 and aligned with slot 340.
Cylinder 341 defines a through hole 344. Drive pin 312
is received within slot 342 and hole 344. An additional
sleeve bearing 346 is located in through hole 344 of
cylinder 341. The combination of slots 340 and 342 and
sleeve bearing 338 permit drive pin 312 to move along
arrow 309. Sleeve bering 346 permits drive pin 312 to
rotate about its axis, E, and slide along its axis, E.
If the two cylinders of the piston assembly are
configured other than 180 apart, or more than two
cylinders are employed, movement of cylinder 341 in
sleeve bearing 338 along the direction of arrow 350
allows for the additional freedom of motion required to
prevent binding of the pistons as they undergo a figure 8
motion, discussed below. Slot 340 must also be sized to
provide enough clearance to allow the figure 8 motion of
the pin.
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Referring to FIGS. 24 and 24a, U-joint 318 defines
a central pivot 352 (drive pin axis, E, passes through
center 352), and includes a vertical pin 354 and a
horizontal pin 356. Transition arm 310 is capable of
pivoting about pin 354 along arrow 358, and about pin 356
along arrow 360.
Referring to FIGS. 25, 25a and 25b, as an
alternative to a spherical bearing, to couple transition
arm 310 to flywheel 322, drive arm 320 is received within
a cylindrical pivot pin 370 mounted to the flywheel
offset radially from the center 372 of the flywheel by an
amount, e.g., 2.125 inches, required to produce the
desired swing angle, a(FIG. 22), in the transition arm.
Pivot pin 370 has a through hole 374 for receiving
drive arm 320. There is a sleeve bearing 376 in hole 374
to provide a bearing surface for drive arm 320. Pivot
pin 370 has cylindrical extensions 378, 380 positioned
within sleeve bearings 382, 384, respectively. As the
flywheel is moved axially along drive arm 320 to vary the
swing angle, a, and thus the compression ratio of the
assembly, as described further below, pivot pin 370
rotates within sleeve bearings 382, 384 to remain aligned
with drive arm 320. Torsional forces are transmitted
through thrust bearings 388, 390, with one or the other
of the thrust bearings carrying the load depending on the
direction of the rotation of the flywheel along arrow
386.
Referring to FIG. 26, to vary the compression and
displacement of piston assembly 300, the axial position
of flywheel 322 along axis, A, is varied by rotating a
shaft 400. A sprocket 410 is mounted to shaft 400 to
rotate with shaft 400. A second sprocket 412 is
connected to sprocket 410 by a roller chain 413.
Sprocket 412 is mounted to a threaded rotating barrel
414. Threads 416 of barrel 414 contact threads 418 of a
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stationary outer barrel 420. Rotation of shaft 400,
arrow 401, and thus sprockets 410 and 412, causes
rotation of barrel 414. Because outer barrel 420 is
fixed, the rotation of barrel 414 causes barrel 414 to
move linearly along axis, A, arrow 403. Barrel 414 is
positioned between a collar 422 and a gear 424, both
fixed to a main drive shaft 408. Drive shaft 408 is in
turn fixed to flywheel 322. Thus, movement of barrel 414
along axis, A, is translated to linear movement of
flywheel 322 along axis, A. This results in flywheel 322
sliding along axis, H, of drive arm 320 of transition arm
310, changing angle, g, and thus the stroke of the
pistons. Thrust bearings 430 are located at both ends of
barrel 414, and a sleeve bearing 432 is located between
barrel 414 and shaft 408.
To maintain the alignment of sprockets 410 and
412, shaft 400 is threaded at region 402 and is received
within a threaded hole 404 of a cross bar 406 of assembly
case structure 303. The ratio of the number of teeth of
sprocket 412 to sprocket 410 is, e.g., 4:1. Therefore,
shaft 400 must turn four revolutions for a single
revolution of barrel 414. To maintain alignment,
threaded region 402 must have four times the threads per
inch of barrel threads 416, e.g., threaded region 402 has
thirty-two threads per inch, and barrel threads 416 have
eight threads per inch.
As the flywheel moves to the right, as viewed in
FIG. 26, the stroke of the pistons, and thus the
compression ratio, is increased. Moving the flywheel to
the left decreases the stroke and the compression ratio.
A further benefit of the change in stroke is a change in
the displacement of each piston and therefore the
displacement of the engine. The horsepower of an
internal combustion engine closely relates to the
displacement of the engine. For example, in the two
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cylinder, flat engine, the displacement increases by
about 20% when the compression ratio is raised from 6:1
to 12:1. This produces approximately 20% more horsepower
due alone to the increase in displacement. The increase
in compression ratio also increases the horsepower at the
rate of about 5% per point or approximately 25% in
horsepower. If the horsepower were maintained constant
and the compression ratio increased from 6:1 to 12:1,
there would be a reduction in fuel consumption of
approximately 25%.
The flywheel has sufficient strength to withstand
the large centrifugal forces seen when assembly 300 is
functioning as an engine. The flywheel position, and
thus the compression ratio of the piston assembly, can be
varied while the piston assembly is running.
Piston assembly 300 includes a pressure
lubrication system. The pressure is provided by an
engine driven positive displacement pump (not shown)
having a pressure relief valve to prevent overpressures.
Bearings 430 and 432 of drive shaft 408 and the interface
of drive arm 320 with flywheel 322 are lubricated via
ports 433 (Fig. 26).
Referring to FIG. 27, to lubricate U-joint 318,
piston pin joints 306, 308, and the cylinder walls, oil
under pressure from the oil pump is ported through the
fixed U-joint bracket to the top and bottom ends of the
vertical pivot pin 354. Oil ports 450, 452 lead from the
vertical pin to openings 454, 456, respectively, in the
transition arm. As shown in FIG. 27A, pins 312, 314 each
define a through bore 458. Each through bore 458 is in
fluid communication with a respective one of openings
454, 456. As shown in FIG. 23, holes 460, 462 in each
pin connect through slots 461 and ports 463 through
sleeve bearing 338 to a chamber 465 in each piston.
Several oil lines 464 feed out from these chambers and
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are connected to the skirt 466 of each piston to provide
lubrication to the cylinders walls and the piston rings
467. Also leading from chamber 465 is an orifice to
squirt oil directly onto the inside of the top of each
piston for cooling.
Referring to FIGS. 28-28c, in which assembly 300
is shown configured for use as an aircraft engine 300a,
the engine ignition includes two magnetos 600 to fire the
piston spark plugs (not shown). Magnetos 600 and a
starter 602 are driven by drive gears 604 and 606 (FIG.
28c), respectively, located on a lower shaft 608 mounted
parallel and below the main drive shaft 408. Shaft 608
extends the full length of the engine and is driven by
gear 424 (Fig. 26) of drive shaft 408 and is geared with
a one to one ratio to drive shaft 408. The gearing for
the magnetos reduces their speed to half the speed of
shaft 608. Starter 602 is geared to provide sufficient
torque to start the engine.
Camshafts 610 operate piston push rods 612 through
lifters 613. Camshafts 610 are geared down 2 to 1
through bevel gears 614, 616 also driven from shaft 608.
Center 617 of gears 614, 616 is preferably aligned with
U-joint center 352 such that the camshafts are centered
in the piston cylinders, though other configurations are
contemplated. A single carburetor 620 is located under
the center of the engine with four induction pipes 622
routed to each of the four cylinder intake valves (not
shown) . The cylinder exhaust valves (not shown) exhaust
into two manifolds 624.
Engine 300a has a length, L, e.g., of about forty
inches, a width, W, e.g., of about twenty-one inches, and
a height, H, e.g., of about twenty inches, (excluding
support 303).
Referring to FIGS. 29 and 29a, a variable
compression compressor or pump having zero stroke
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capability is illustrated. Here, flywheel 322 is
replaced by a rotating assembly 500. Assembly 500
includes a hollow shaft 502 and a pivot arm 504 pivotally
connected by a pin 506 to a hub 508 of shaft 502. Hub
508 defines a hole 510 and pivot arm 504 defines a hole
512 for receiving pin 506. A control rod 514 is located
within shaft 502. Control rod 514 includes a link 516
pivotally connected to the remainder of rod 514 by a pin
518. Rod 514 defines a hole 511 and link 516 defines a
hole 513 for receiving pin 518. Control rod 514 is
supported for movement along its axis, Z, by two sleeve
bearings 520. Link 516 and pivot arm 514 are connected
by a pin 522. Link 516 defines a hole 523 and pivot arm
514 defines a hole 524 for receiving pin 522.
Cylindrical pivot pin 370 of FIG. 25 which
receives drive arm 320 is positioned within pivot arm
504. Pivot arm 504 defines holes 526 for receiving
cylindrical extensions 378, 380. Shaft 502 is supported
for rotation by bearings 530, e.g., ball, sleeve, or
roller bearings. A drive, e.g, pulley 532 or gears,
mounted to shaft 502 drives the compressor or pump.
In operation, to set the desired stroke of the
pistons, control rod 514 is moved along its axis, M, in
the direction of arrow 515, causing pivot arm 504 to
pivot about pin 506, along arrow 517, such that pivot pin
370 axis, N, is moved out of alignment with axis, M, (as
shown in dashed lines) as pivot arm 504 slides along the
axis, H, (FIG. 26) of the transition arm drive arm 320.
When zero stroke of the pistons is desired, axes M and N
are aligned such that rotation of shaft 514 does not
cause movement of the pistons. This configuration works
for both double ended and single sided pistons.
The ability to vary the piston stroke permits
shaft 514 to be run at a single speed by drive 532 while
the output of the pump or compressor can be continually
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varied as needed. When no output is needed, pivot arm
504 simply spins around drive arm 320 of transition arm
310 with zero swing of the drive arm. When output is
needed, shaft 514 is already running at full speed so
that when pivot arm 504 is pulled off-axis by control rod
514, an immediate stroke is produced with no lag coming
up to speed. There are therefore much lower stress loads
on the drive system as there are no start/stop actions.
The ability to quickly reduce the stroke to zero provides
protection from damage especially in liquid pumping when
a downstream blockage occurs.
If two cylinders not spaced 180 apart (as viewed
from the end) or more than two cylinders are employed in
piston assembly 300, the ends of pins 312, 314 coupled to
joints 306, 308 will undergo a figure 8 motion, as shown
in FIG. 30. FIG. 30 shows the figure 8 motion of a
piston assembly having four double ended pistons. Two of
the pistons are arranged flat as shown in FIG. 22 (and do
not undergo the figure 8 motion), and the other two
pistons are arranged equally spaced between the flat
pistons (and are thus positioned to undergo the largest
figure 8 deviation possible) . The amount that the pins
connected to the second set of pistons deviate from a
straight line (y axis of FIG. 30) is determined by the
swing angle (mast angle) of the drive arm and the
distance the pin is from the central pivot point 352 (x
axis of FIG. 30).
In a four cylinder version where the pins through
the piston pivot assembly of each of the four double
ended pistons are set at 45 from the axis of the central
pivot, the figure eight motion is equal at each piston
pin. Movement in the piston pivot bushing is provided
where the figure eight motion occurs to prevent binding.
When piston assembly 300 is configured for use,
e.g., as a diesel engines, extra support can be provided
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at the attachment of pins 312, 314 to transition arm 310
to account for the higher compression of diesel engines
as compared to spark ignition engines. Referring to FIG.
31, support 550 is bolted to transition arm 310 with
bolts 551 and includes an opening 552 for receiving end
554 of the pin.
Engines according to the invention can be used to
directly apply combustion pressures to pump pistons.
Referring to FIGS. 32 and 32a, a four cylinder, two
stroke cycle engine 600 (each of the four pistons 602
fires once in one revolution) applies combustion pressure
to each of four pump pistons 604. Each pump piston 604
is attached to the output side 606 of a corresponding
piston cylinder 608. Pump pistons 604 extend into a pump
head 610.
A transition arm 620 is connected to each cylinder
608 and to a flywheel 622, as described above. An
auxiliary output shaft 624 is connected to flywheel 622
to rotate with the flywheel, also as described above.
The engine is a two stroke cycle engine because
every stroke of a piston 602 (as piston 602 travels to
the right as viewed in FIG. 32) must be a power stroke.
The number of engine cylinders is selected as required by
the pump. The pump can be a fluid or gas pump. In use
as a multi-stage air compressor, each pump piston 606 can
be a different diameter. No bearing loads are generated
by the pumping function, and therefore, no friction is
introduced other than that generated by the pump pistons
themselves.
Other embodiments are within the scope of the
following claims.
