Note: Descriptions are shown in the official language in which they were submitted.
~51322
Background of the Invention
This invention relates to unidirectional rotary ex- ;
pansion steam power units of the type having a planetating rotor,
and more particularly to an improvement in means for effecting
rotation of the rotor in such engines.
In rotary expansion steam engines of the Wankel type, --
the flow of pressure fluid into the working chambers is con-
trolled by valves external to the engine cavity, the action of
which valves is synchronized with the rotor motion through the
crankshaft and gear trains or like systems. Such engines are
known as variable cutoff or variable displacement engines -~
because the amount of steam admitted, and hence the expansion
thereof, may be varied by altering the time during which the
inlet valv~s are open. This necessity for external valves
and mechanisms for timing their operation results in an ex-
pansion engine of relatively great complexity, bulkiness, and
cost. Therefore, expansion engines of the Wankel type have not
heretofore been competitive with sliding vane type expansion
engines, in spite of the greater capability and ef~iciency of
the Wankel type engines.
Summary of the ~n_ention
This invention comprises an expansion power unit
having a planetating rotor which re~uires no external valves
and timing mechanisms and hence is relatively small in size,
simple in construction, and inexpensive to operate. The
planetating rotor itself functions in cooperation with passages
in the housing walls to control the timing and duration of the
flow of pressure fluid to and from working chambers. An added
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valuable feature of the invention is the fact that it is adapted
for starting without the use of a separately powered external
starting system, and for operation always in a single direction. `
The units are also well adapted for either direct or compound
energization with the power fluid.
Internal combustion single rotor engines produce
intermittent torq~e, and, depending or port design, may produce
a negative torque during a portion of one single rotation, thus
requiring a flywheel and operation with minimum rotational
speeds of approximately 500 rpm. Because my single rotor
engine delivers uninterrupted torque moments, it is capable of
slow speed operation and does not require a flywheel as does a
Wankel type internal combustion engine.
To achieve these benefits, I provide a housing having
opposed end walls spaced by a peripheral wall to define a multi-
lobed cavity in which a hollow rotor is constrained to perform
what I define as planetation movement, that is, revolution about
a first axis combined with rotation about a second axis which
remains parallel to the first axis, the speed of rotation having
a known relation to the speed of revolution. The rotor has side
wall surfaces which intersect at apices to determine lines of
sealing contact with the peripheral wall of the housing which
define a plurality of planetating working chambers. The cham-
bers successively increase and decrease in volume as they follow
the movement of the rotor. The side wall surfaces of the rotor
are in apposition and in slightly spaced relation to the end
walls of the housing, and carry seal means for preventing the
escape o~ pressure fluid continuously supplied to the hollow
rotor. On at least one side wall surface the seal means in-
cludes inner,valviny seal means extending around the rotor~ and
outer, working chamber isolation seal means. At least the
adjacent end wall of the housing is provided with passage means
~5~Z~Z
effective to conduct power fluid past the seal means to the
working chambers during first portions of the rotor movement,
and to provide egress for said fluid from said working chambers
during second portions of the rotor movement.
A feature of the invention is that the passage means
in the housing end wall can be so located as to prevent power
fluid from being supplied to any working chamber prematurely
to the extent of creating an undesirable negative torque, a
defect usually found in fixed-displacement or fix~d-cutoff
engines lacking external valves and valve gear. As a result
my engine may be designed to provide positive and uninterrupted
torque at any speed above zero rpm.
Various advantages and features of novelty which
characterize my invention are pointed out with particularity
in the claims annexed hereto and forming a part hereof. However,
for a better understanding of the invention, its advantages,
and objects attained by its use, reference should be had to
the drawing which forms a further part hereof, and to the
accompanying descriptive matter, in which there is illustrated
and described a preferred embodiment of the invention.
The invention is directed to a rotating machine
comprising, in combination:
a housing having opposite end walls spaced apart
a.l.ong a first axis b~ a peripheral wall shaped to define an
epitrochoidal cavity s~mmetrical about the first axis and
configured as two lobes intersecting at lobe junctures which
define a minor axis of the section of the housing normal to
the first axis, one of the lobes lying in first and second
quadrants about the first axis and the other lying in third and
fourth ~uadrants thereabout;
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a rotor symmetrical about a further axis and movable
in the cavity, the rotor having opposite side wall surfaces
adjacent, and in slightly spaced relation, to the end walls of
the housing, and intercon~ected by a plurality of peripheral
flank surfaces which intersect at apices to determine lines of
sealing contact with the peripheral wall;
means, including a crankshaft on which the rotor . -
rotates on the further axis eccentrically with respect to the
first axis, for limiting motion of the rotor in the cavity to
10 planetating movement about the first axis in the direction from ~:
the fourth quadrant to the first quadrant, so that the apices
sweep through the lobes;
spaced seal means, including inward valving seal means
and outward chamber isolating seal means, carried by the side wall ..
surfaces of the rotor to move in the interstices between the
side wall surfaces and the adjacent end walls of the housing, so
that the rotor and the housing jointly define a plenum space
inward of the valving means and a plurality of distinct working
chambers, outward of the isolating seal means, which move about
the first axis and successively increase and decrease in volume
with the movement of the rotor;
means for conducting a fluid into the housing at a . `
site inward of the valving seal means;
bridging passage means in the inner surEaces of the
end walls, sized to conduct fluid from the plenum space to the
working chambers during first predetermined portions of the
movement, the bridging passage means being positioned off the
minor axis in the odd numbered ones of the quadrants and extend-
ing inward from near the location of the peripheral wall to
sites lying inward of the valving seal means during the first
predetermined portions of the movement;
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:~65!322
and further passage means in the inner surfaces of
the end walls for affording fluid connection with the working :.
chambers during second predetermined portions of the movement, .. .;
the further passage means being positioned off the minor axis
in the even numbered ones of the quadrants to always lie outward
of the valving seal means, and to be located between the valving
and isolating seal means except during the second predetermined
portions of the movement.
According to another broad aspect of the invention
there is provided in a rotating machine including a housing
having opposite end walls spaced apart along a first axis by a
peripheral wall shaped to define an epitrochoidal cavity
symmetrical about the first axis and configured as two lobes
intersecting at lobe junctures which define a minor axis oE the
section of the housing normal to the first axis, one of the
lobes lying in first and second quadrants about the first axis
and the other l~ing in third and fourth quadrants thereabout;
a rotor symmetrical about a further axis and movable
in the cavity, the rotor having opposite side wall surfaces
adjacent, and in slightly spaced relation, to the end walls of
the housing, and interconnected by a plurality of peripheral
flank surfaces which intersect at apices to determine lines of
sealing contact with the peripheral wall of the housing;
means, including a crankshaft on which the rotor
rotates on the further axis eccentrically with respect to the
first axis, for limiting motion of the rotor in the cavity to
planetating movement about the first axis in the direction from
the fourth quadrant to the first quadrant, so that the apices
sweep through the lobes;
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spaced seal means, including inward valving seal means
and outward chamber isolating seal means, carried by at least
one side wall surface of the rotor to move in the interstice
between the side wall surface and the adjacent end wall of the
housing, so that the rotor and the housing jointly define a
plenum space inward of the valving seal means and a plurality of
distinct working chambers, outward of the isolating seal means,
which move about the first axis and successively increase and -`
decrease in volume with the movement of the rotor; `
and means for conducting a fluid into the housing at
a site inward of the valving seal means, the improvement which
comprises~
bridging passage means in the inner surface of
at least one of the end walls, sized to conduct
pressure fluid from the plenum space to the working
chambers during first predetermined portions of
khe movement;
and further passage means in the inner surface
of the one of the end walls for affording egress of
pressure fluid from the working chambers during
second predetermined portions of the moveme~t.
According to yet another broad aspeck of the invention
there is provided in a rotating machine including a housing
having opposite end walls spaced apart along a first axis by a
peripheral wall shaped to define an epitrochoidal cavity
symmetrical about the first axis and configures as two lobes
intersecting at lobe junctures which define a minor axis of the ~
section of the housing normal to the first axis, one of the . ~.
lobes lying in first and second quadrants about the first axis
30 and the other lying in third and fourth ~uadrants thereabout; ~:
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1~;D65822
a rotor symmetrical about a further axis and movable
in the cavity, the rotor having opposite side wall surfaces
adjacent, and in slightly spaced relation, to the end walls of
the housing, and interconnected by a plurality of peripheral
flank surfaces which intersect at apices to determine lines
of sealing contact with the peripheral wall of the housing;
means, including a crankshaft on which the rotor
rotates on the further axis eccentrically with respect to the
first axis, for limiting motion of the rotor in the cavity to
planetating movement about the first axis in the direction from
the fourth quadrant to the first quadrant, so that the apices
sweep through the lobes;
spaced seal means, including inward valving seal means
and outward chamber isolating seal means, carried by at least
one side wall surface of the rotor to move in the interstice
between the side wall surface and the adjacent end wall of the
housing, so that the rotor and the housing jointly define a
plenum space inward of the valving seal means and a plurality of
distinct working chambers, outward of the isolating seal means,
which move about the first axis and successively increase and
decrease in volume with the movement of the rotor;
and means for conducting a fluid into the housing at a
site inward of the valving seal means, the imp.rovement which
comprises:
! bridging passage means in the inner surface
of at least one of the end walls, sized to conduct
pressure fluid between the plenum space and the
working chambers during first predetermined portions
of the movement, the bridging passage means being
positioned off the minor axis in an odd numbered
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one of the quadrants and extendin~ inward from
near the location of the peripheral wall to a site
lying inward oE the valving seal means during the
first predetermined portions of the movement; :~
and further passage means in the inner : :
surface of the one of the end walls for affording
egress of pressure fluid from the working chambers
during second predetermined portions of the
movement.
~inally, in accordance with yet another broad aspect
of the invention there is provided in a rotating machine including
a housing having opposite end walls spaced apart along a first
axis by a peripheral wall shaped to define an epitrochoidal :
cavity symmetrical about the first axis and configured as two
lobes intersecting at lobe junctures which define a minor axis
of the section of the housing normal to the first axis, one of :
the lobes lying in first and second quadrants about the first
axis and the other lying the third and fourth quadrants thereabout;
a rotor symmetrical about a further axis and movable
in the cavity, the rotor having opposite side wall surfaces
adjacent, and in slightly spaced relation, to the end walls of `
the housing, and interconnected by a plurality of peripheral ;~
flank surfaces which intersect at apices to determine lines o~
sealing contact with the peripheral wall of the housing;
means, including a crankshaft on which the rotor
rotates on the further axis eccentrically with respect to the
first axis, for limitlng motion of the rotor in the cavity to
planetating movement about the first axis in the direction from
the fourth quadrant to the first quadrant, so that the apices
sweep through the lobes;
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spaced seal means, including inward valving seal means
and outward chamber isolating seal means, carried by at least
one side wall surface of the rotor to move in the interstice
between the side wall surface and the adjacent end wall of the
housing, so that the rotor and the housing jointly define a
plenum space inward of the valving seal means and a plurality
of distinct working chambers, outward of the isolating seal
means, which move about the first axis and successively increase
and decrease in volume with the movement of the rotor;
and means for conducting a fluid into the housing at a
site inward of the valving seal means, the improvement which
comprises:
bridging passage means in the inner surface of at
least one of the end walls, sized to conduct pressure
fluid from the plenum space to the working chambers
during first predetermined portions of the movement,
the bridging passage means being positioned off the
minor axis in an odd numbered one of the quadrants and
extending inward from near the location of the
peripheral wall to a site lying inward of the valving
means during the first predetermined portions of the
movement;
and further passage means in the inner surface of
the one of the end walls for affording egress of
pressure fluid from the working chambers during second
predetermined portions of the movement, the second
passage means being positioned off th~ minor axis in
an even numbered one of the quadrants to always lie
outward of the valving seal means, and to be located
between the seal means except during the second
predetermined portions of the movement.
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Please refer to the claims appended hereto for a
description of further modifications to the invention. .
Brief Description of the Drawings ~
In the drawing, FIGURE 1 is a view of a power unit - -
according to my invention seen axially, with an end wall removed
for clarity of illustration;
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~6S1~22
FIGURE 2 iS an enlarged sectional vi.ew of the power
unit, taken generally along the line 2-2 of FIGURE 1 and show-
ing the rotor in a "dead-center" position; I .
FIGURES 3, 4 and 5 are views like FIGURE 2 showing
the rotor in other positions,
FIGURE 6 is a diagram illustrating the principles
~ determining the shapes and locations of passage means essential
-- to the invention; and
FIGURE 7 shows a power system made up of a plurality
.- 10 of power untis as disclosed in FIGURES 1-5.
.~ Description of the Preferred Embodiment
:. As shown in FIGURES 1-5, a power unit according to my
invention comprises a housing 11, a rotor 12, and a crankshaft
13. Housing 11 comprises a pair of opposite end walls 14 and
15, spaced apart along the axis 16 of crankshaft 13 by a peri-
pheral wall 17 shaped to define a cavity 20 symmetrical about
axis 16 and having a pair of epitrochoidal lobes 21 and 22 which
intersect at lobe iunctures 23 and 24 which define the minor axis .
of the housing. Crankshaft 13 is mounted in bearing inserts 18 `.
and 19 in end plates 14 and 15, and includes an eccentric 25 which
is itself circular in traverse section to engage a hollow circular .`
il bearing 26 in rotor 12. The rotor is symmetrical about the axis ..
27 of bearing 26 and eccentric 25 and hence is radially displaced ..
from axis 16 by an eccentricity e. It compris.es a pair of op~
po~ite side wall ~urfaces 30 and 31, adjacent and in slightly ;.
spaced relation to housing end walls 14 and 15, and interconnect- ~
ed by a plurality of smooth epitrochoidal flank surfaces 32,33 and :
34 which intersect at apices 35, 36 and 37. The rotor includes .:.:
a rim 40 of varying thickness, a web 41, and a hub 42 containing .:
bearing 26. Web 41 is provided with a plurality of paraxial
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~L~65822
apertures 43. Rotor 12 is referred to as hollow to define aper-
tures 43 and the spaces 44 and 45 inward from rim 40 on each ~;
side of web 41 which function as a plenum space. An external
gear 46 is fixed to bearing insert 19 concentric with axis 16
and hence with crankshaft 13, and an internal gear 47 is fixed
in rotor 12 concentric ~o axis 27 to mesh with gear 460 -
For the structure shown, where housing 11 has two lobes
and rotor 12 has three apices, the tooth ratio between gear 47 ~ `
; and gear 46 is 3:2. It will be appreciated that epi~rochoidal
cavities of more lobes can be used, with rotors of more apices,
and that the gear ratio will change accordingly. Crankshaft 13
is mounted for rotation in bearings 50 and 51 carried by inserts
18 and 19, respectively.
Eccentric 25 and gears 46 and 47 combine to limit the
movement of rotor 13 in housing 11 to a combination o rotation
about axis 27 and revolution about axis 16, which I have defined
as planetating movement. Apices 35, 36 and 37 define the
location of lines of sealing contact between the rotox and the
housing, and may be provided with suitable seal bl~des 52, 53
and 540 Rotor flanks 32, 33 and 34 and housing lobes 21 and 22
combine to define a plurality of wor]cing chambers 55, 56 and 57,
which moVe about axis 16 with movement of flank sur~aces 32, 33 ~"
and 3~ respectively o~ the rotor, decxeasing and increasing in
volume cyclically as they do so.
Pressure fluid is supplied to the hollow rotor from
a source such as a steam boiler, not .shown, through a conduit `
59 and an inlet connection 60 to an annular channel 61 in wall `
14, and ik is intended to be supplied to working chambers 55, ~
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56, and 57 at appropriate times to act on the rotor flanks 32,
33 and 34 respectively so as to cause rotor planetation in a
generally clockwise direction as seen in FIGURE 1. To this
end, O-rings 62 or other suitable means are provided between
wall 17 and walls 14 and 15, respectively, and similar O~rings
63 are provided to seal inserts 18 and 19 to housing walls 14
and 15. Side wall surfaces 30 and 31 are also provided with
seal means to control the flow of pressure fluid in the
interstices 64 and 65 between them and housing end walls 14 and
15, all respectively. These seal means comprise valving seal
means and working chamber isolation seal means respectively.
The former comprises sealing rings 66 of sealing material
received in circular grooves 70 in the rotor side wall suraces.
The latter comprises sealing members 67, 68 and 69 received in
grooves 71 in the side wall faces and suitably sealed at their
ends to blades 52, 53 and 54.
In the inner surface of wall 15, in the area of lobe ~ `
22 near lobe junction 23 (FIG. 1), there is provided first
passage means comprising a plurality of grooves 72a, 72b, 72c
extending generally radially from axis 16, and for a double
acting engine similar grooves 73a, 73b and 73c, axe similarly
located in the like area of lobe 21. The purpose and location
of these passage means is to conduct pressure fluid from the
hollow rotor to the cavity lobes at appropriate times to cause
the desired motion of rotor 12 by pressure on a flank thereof.
In the "dea~-center" position of the crankshaft, shown in
~IGURE 1, working chamber 57 is at its smallest volume, and
passage means 73 conducts pressure fluid past seal means 66
and 69 to lobe 21 to act on flank surfac~ 34 of rotor 12,
while passage means 72 does not reach past seal means 66
and hence does not supply pressure fluid to lobe 22 to
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act on flank surface 33. Other conditions are illustrated in :~
FIGURES 3-5 and will be discussed presently below.
Further passage means 74, 75 are provided in wall 15
at locations near lobe junctions 23 and 24. The purpose of
these passages is to provide egress for pressure fluid from ~ `
cavity lobes 21 and 22 at appropriate times, and for this ~.
purpose, they are connected through apertures 76, 77 and con-
duits 80 and 81 to an exhaust connection, not shown, which may
be a condenser for reducing the exhaust steam to water and .-
returning it to the boiler. As shown in FIGURE 1, working
chamber 55 is in communication with passage 74, while passage
75 is isolated by seal means 66 and 69. Again, other conditions
are illustrated in PIGURES 3-5. ~
In FIGURES 1 and 2, there are shown additional con-
duits 82 and 83 leading to passages 72 and 73, and connected as
at 84 to inlet conduit 59 through a starting valve 85. `
For an understanding of the principles underlying the
location and shaping of passage means 72, 73, reference should :
now be made to FIGURE 6. In this Figure O is the axis of ro-
tation of the crankshaft, e is the eccentricity of the eccentric
25, and R is the inside radius of sealing ring 66. Two angles
A and B are of interest, and will presently be de:Eined. It will : ;
be realized that the circle O of radius e traces the path o the
center o the aircular eccentric around the crankshaft axis, and . :
the circle O of radius R + e is the outer limit of all positions
of the sealing ring. Dead center of the crankshaft is a position
in which eccentric 25 is nearest to a lobe juncture, and is also
as has been pointed out, the position o~ minimum volume of a
working chamber. Moreover, at this crankshaft position the moment .
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1~165~22
arm o~ pressure acting on the rotor flank defining that working
chamber is zero. Power fluid admitted to the working chamber later
in the rotation of the crankshaft cannot have a negative tor~ue
effect on the rotor, and passage means 72, 73 could be designed
not to admit fluid before then. However, a finite interval is
required for the passage of power fluid into the chamber, and --
practically the fluid admission can begin a few degrees ahead
dead center, to have the minimum volume of the working chamber
fully charged with power fluid by the time the rotor is in the
dead-center position, without building up a significant reverse
torque, particularly since the moment arm is approaching zero.
A lead angle of ten degrees not only may be tolerable, but is
desirable to insure adequate filling of the working chamber
with power 1uid. This is the angle A of FIGURE 6.
The angle B is defined purely geometrically. It is
the position of the rotor at which the volume Z of the working
chamber reaches a value, compared to the maximum volume, which ;
is the reciprocal of the expansion ratio. The latter is chosen ~ ~-
as a matter of design, having a bearing on the efficiency of the
engine and its power output. An expansion ratio of 8:1 is
representative. In determining the volume it is necessary to
consider not only the space between a flank of the rotor and ~;
the apposed housing wall~ but al~o the volumes o~ th~ grooves
making up passage means 72 and 73: these passages should there-
fore be as shallow as can be without restricting tha flow of
power fluid unduly. As shown in ~he Figure, a typical value for
angle B is 105.
The shaded area in FIGURE 6 is defined by the circle
of radius R plus e centered on O, and by two circles of radius
R centered on the circle of radius e at the radii defining
angles A and b respectively. Passage means 72 should terminate
inwardly within this area for optimum operation of my engine.
~;5~322
To the extent that the inner edges of the grooves lie further ~
inward than this area, the power of the engine suffers because .~:
power fluid is then permitted to enter the working chamber pre-
maturely, resulting in a negative torque component at the
crankshaft. Outwardly the passage means must extend quite close
to wall 17 to communicate with t.he working chambers in their
minimum volume condition. The same principles apply in respect
to passage means 7~a, 73b and 73c. ..
I have shown three grooves in side-by-side relation.
One advantage of this arrangement over a single wider groove is
that it is less wearing on sealing member 66 as it sweeps over
the area when support ridges are present. The actual shape of ~
the grooves is not critical: in FIGURE 6 I have shown grooves
73a, 73b and 73c as having a slightly different configuration
from grooves 72a, 72b and 72c, but it is to be noted that they
all terminate inwardly within the critical shaded area.
Passage means 74 are not so critical. It is only
necessary that they be positioned for uncovering by sealing
members 67, 68,69 when the working chambers have reached their
maximum volume and for re-covering before power fluid is next
admitted to the working chambers, and that they be large enough
to prevent restriction in the exhaust flow of power .~luid.
This function may :indeed be performed by an outlet passage
properly positioned in wall 17, as suggested by the dotted
line passage 78 in FIGURE 6. For convenience of description
it may be said that inlet passages are located in the first and
third quadrants, and outlet passages are located in the second
and fourth quadrants. ;;~
A cycle of driven operation of my crankshaft 13 will
now be traced through FIGURES 1, 3, 4 and 5. For the locations
1~6582~ ~
of passage means 72, 73, 74 and 75 shown, the rotation of the
crankshaft is clockwise, as is the planetation of rotor 12 in
cavity 20. In the position of the rotor shown in FIGURE 1,
working chamber 55 is free to exhaust at passage means 74,
chamber 56 is closed off but filled with pressure fluid,
although not yet at its maximum volume, and chamber 57 is open
at passage means 73 to admit power fluid, and is at its minimum ` ~
volume. The moment arm of power fluid force on flank 34 acting -~ -
on crankshaft 13 through eccentric 25 is momentarily zero, but ' -
the fluid foxce on flank 33 has a moment arm in a direction to
rotate the crankshaft clockwise, and as soon as the "dead-center"
position is passed, the moment arm of the fluid force on flank :
34 increases in the same direction, while that on flank 33
decreases.
Rotation of crankshaft results, and is accompanied by ;
planetation of rotor 12. After 90 degrees of rotation of crank-
shaft 13, which accompanies 30 degrees of rotation of rotor 12
about axis 27, sealing ring 66 closes off passage means 73 from
communication with chamber 57, isolating the power fluid in
chamber 57 to give up its energy by expansion. After about 150
degrees rotation of the crankshaft, which accompanies 50 degrees
of rotation of rotor 12 about axis 27, sealing member 67 closes
o~ passage means 74 and sealing ring 68 opens passage means 75.
FIGURE 3 shows the relative position of the parts after 180
degrees of rotation of the crankshaft, accompanied by 60 degrees
of rotation of the rotor.
FIGURES 4 and 5 show respectively the relative
positions of the parts after 210 degrees and 300 degrees re-
spectively of crankshaft rotation, which accompanies 70 degrees
and 100 degrees respectively of rotation of rotor 12.
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It will be appreciated that each rotation of the crank-
shaft by 360 degrees is accompanied by rotor rotation of 120
degrees, in which the cycle just described for flank 34 is
repeated for flank 33 and then for flank 32. Three crankshaft
cycles are needed for a single rotor cycle.
Referring again to FIGURES 3 and 2, the need for
elements 82, 83 and 85 will nGw be apparent. If valve 85 is
open momentarily, pressure fluid is admitted to the working
chamber via passages 82 and 83. Although passage means 75 is ;
open to exhaust, chamber 57 is sealed, so the fluid pressure on
flank surface 34 causes rotation of the crankshaft in the desired
direction. After starting is accomplished, valve 85 is closed
and engine operation continues as originally described.
It will ~e appreciated that the power unit just des-
cribed functions as the equivalent of a three-cylinder piston
engine: each flank of rotor 12 is sub~ect to two power strokes
per rotation of the rotor about axis 27, which accomplishes
three rotations of crankshaft 13 about axis 16.
The power obtainable from any engine is determined by
its displacement. In piston engines, the total power available
is increased not only by increasing the size oE the cylinders
but by increasing their number, the pistons acting about a
common crankshaft, and the same principle is applicable to my
power units, as is shown in FIGURE 7. ~he eEficiency of power
extraction from a pressure fluid is not affected if several
power units on a common crankshaft are supplied individuall~
with the fluid, but may be considerably increased by the prac-
tice known as compounding, which comprises passing the power
fluid through more than one power unit in sequence, extracting
a first portion of the power from the fluid in the first unit
through initial expansion of the power fluid, and extracting more
power in another unit through additional expansion of power fluid,
--11--
16~65~;~2
the sum effect of the successi~e expansions being greater than
can be practically obtained in only one expansion in one unit.
To accomplish this, the displacement of the later unit must be
greater than that of the first unit, to allow for effective
expansion of the pressure fluid exhausting from the first unit.
FIGURE 7 also shows how three of my power units may be compounded,
the fluid exhausting from one being fed to two others. ;
A still further feature of my invention is also shown
in FIGURE 7. Consider the case of a ~ehicle which does most of
its traveling in relatively level country, but must occasionally
traverse extended relatively steep grades. An engine designed
for adequate power to traverse the grades at acceptable speeds
would be operating at an inefficiently low power lev~l in the
substantially flat portions of its travel. I have devised a
conduit system which operates three of my power units in~
dependently or in a compound relation, depending on the position-
ing of a set of valves, to drive a single crankshat. By this
: . .
arrangement, the compounding configuration can be used for
greater efficiency in level terrain, and all units can be
directly energized to obtain greater torque when mountainous
country is encountered. This is the functional equivalent, in
simpler form, of having a second engine to couple in when addi-
tional torque is needed.
FIGVRE 7" speci~ically shows how three o my units may
be arranged in a system for operation e~iciently at a first
power rating, or less eficiency at a higher power rating.
Three power units lOa, lOb, and lOc are used, each like unit
10 described above, and their rotors are carried on a common
crankshaft 89. Pressure fluid is provided to the engines in a
conduit 90 to a manifold 91, which is connected by a first tap
Y12--
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92 to the inlet of unit lOa. The outlets 80a and 81a of unit
lOa are connected by a conduit 93 to a second manifold 94, from -
which conduits 95 and g6 lead to a pair of valves 97 and 100.
These valves are also connected by conduits 101 and 102 to :.
manifold 91, and by conduits 103 and 104 to the inlets of units
lOb and lOc. Manifold 94 is further connected through a valve
105 to a conduit 106. Conduit 106 and the outlets 80b, 80c, .:~-
81b and 81c of units lOb and lOc, are permanently connected to
an exhaust or a condenser. Valves 97, 100 and 105 may be .
interconnected by suitable means 107 for simultaneous operation :-
betw~en two system configurations, as follows. In the irst
onfigu~ation, valve 105 is closed, valve 97 connects conduit
95 to conduit 103, and valve 100 connects conduit 96 to conduit
104. In this coniguration, power fluid is supplied d.irectly
to unit lOa, while units lOb and lOc are energized with the
power fluid exhausted from unit lOa. The combined volumes of
units lOb and lOc are approximately half that of unit lOa. By
the amiliar process of compounding, a first portion o the ...
energy in the pressure 1uid is extracted by unit lOa, and a
second portion is extracted by units lOb and lOc. ~:
If the occasion arises when greater power is needed ~:
and eficiency can be sacrificed, valves 97, 100 and 105 are
moved to establish the second system coniyuration. Here
pressure 1uid is supplied to unit lOa directly as before, to
unit lOb directly through manifold 91, conduit 101, valve 97, ~.
and conduit 103, and directly to unit lOc through manifold 91,
conduit 102, valve 100 and conduit 104: units lOb and lOc ex-
haust as beore, while unit lOa exhausts through conduit 93,
maniold 94, valve 105, and conduit 106.
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An additional advantage of my structure lies in the
fact that it can function as an efficient compressor. Conduits
80 and 81 of FIGURE 1 then comprise the inlet of the machine,
and conduit 59 is the outlet: the shaft 13 must be mechanically
driven in the direction opposite to that in which it runs as a
motor. Check valving is desirable to prevent the compressor -
from being run as an air motor when not being mechanically -
driven. - `
From the foregoing, it will be evident that I have
invented a new and improved rotary expansion power unit which
retains the advantages of power to weight ratio and power to
volume ratio which characterize rotary expansion engines, while
avoiding the complications of external valving and starting
mechanisms, which may operate at low or high speeds because
of its continuous torque, and which is well adapted for use in
a power system in which several units are energized either `
directly or in compound fashion to give the user an election
between maximum available torque and maximum fuel economy. ~`~
Numerous characteristics and advantages of my inven-
tion have been set forth in the foregoing description, together
with details o the structure and unction of the invention, and
the novel features thereof are pointed out in the appended claims.
The disclosure, however, is illustrative only, and changes may
be made in detail, especially in matters o~ shape r size, and
arrangement of parts, within the principle of the invention, to
the full extent indicated by the broad general meaning of the
terms in which the appended claims are expressed.
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