Internal Combustion Engine Having a Spherical Chamber

Technical Field

This invention relates generally to machines which are generic to in- ternal combustion engines and pumps; more specifically, the invention re¬ lates to a rotary engine which is capable of operating on an Otto, Diesel or Stirling cycle, as well as operating as a positive displacement pump. Background Art

The desire of achieving outstanding performance with acceptable fuel consumption and tolerable exhaust products has prompted many different versions of internal combustion engines, most of which are utilized in auto¬ mobi les and trucks around the world. Traditional Otto cycle engines em¬ ploy a plurality of distinct pistons which reciprocate within an engine block and uti lize some mechanism (such as a crank shaft) to convert straight-line motion into rotary motion . Such constructions typically re¬ quire many parts and elaborate lubrication systems, contributing to sub¬ stantial expense in original manufacturing processes and in repairs — when needed. To avoid some of the inherent deficiencies of a device which re¬ quires the changing of a power stoke from a straight-line direction into power output as a rotary motion, it has been proposed to make what are called rotary engines . By use of the expression "rotary engines" most people are likely to think of the fami ly of engines which are progeny of Dr. Felix Wankel . Of course, those who are skilled in the art recognize that even engines having as much initial promise as the Wankel engines

have sometimes proved to have problems that were not readily apparent

from a conceptual study .

Another alternative to the well-known linear engines with their cyl¬ indrical, reciprocating pistons is an engine having a spherical cavity which

is divided into either two or four compartments by a rotating plate and other cooperating parts . Examples of engines having two compartments (and which may therefore be categorized as "two cylinder" engines) are the engines shown in U .S . Patents 3, 156,220 and 3, 156,221 to Miller. Such engines include a rotor whose periphery constitutes a segment of a sphere, so that the rotor may rotate within the spherical housing and be sealed with respect to the inner wall . A nutator moves with respect to the rotor as the rotor rotates about a fixed axis, thereby defining two chambers . During each 360° rotation of the rotor in a 4-cycJe configuration, it would be pos¬ sible to have one power stroke . Of course, such a two-chamber embodi- ment provides only half the effective displacement of a spherical engine which has four chambers instead of two in the same size cavity. Hence, if it should be essential for a designer to achieve a given amount of dis¬ placement in order to power a certain sized automobi le or the like, it would be necessary to utilize two of the 2-cylinder devices instead of a single 4-cy Under construction. In effect, then, there is both a weight and ^" space penalty with a Miller-type engine, as compared with a spherical engine having compression and expansion functions on both sides of a central dividing plate, instead of on only one side of the plate.

Another group of sperical-cavity engines includes those which uti-

Hze a design disclosed nearly 100 years ago in U .S. Patent 295, 380 to

Froude (patented in March 18, 1884) . A more modern example of the

Froude concept is found in U .S . Patent 3, 877, 850 to Berry . An advantage

of the Berry-type construction is that it may accurately be described as

equivalent to a four-cylinder engine, because there are four separate com-

partments which reach a maximum and a minimum size during each revolu¬ tion of a power output shaft. Unfortunately, two of the four compartments

are 90° out of phase with respect to the other two compartments , which

means that it is impossible to have cooperation between pai rs of compart¬

ments . As illustrated in Figure 1 of the Berry '850 patent, the two com-

partments which are on the right side of the plate 25 (i.e. , the compart¬ ments which are perpendicular to the plane of the drawing) are respec¬ tively at their maximum and minimum sizes, whereas the two compartments on the left side of the plate are both 90° away from their respective minimum and maximum sizes . One result of such a construction is that the ignition sequence for compartments on opposite sides of the plate occur 90° apart, followed by 270° with no ignition. Such an asymmetrical fi ring sequence

would cause undesi rable roughness in engine operation, and would almost

necessarily dictate that there be a companion device which is connected to

a common power output shaft — in order to "smooth out" the power output from such an engine. While there are some suggestions for variations on

^' the basic Berry design which provide a more symmetrical output, such

variations are restricted to either two-cycle operations without auxiliary compression means or four-cycle operations with auxi liary compression

means . Besides the relatively recent U .S . patents to Berry (3 ,816, 038

and 3, 877, 850) , there are earlier U .S . patents that logically fit in the same

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category of subject matter, including U .S. Patent 826, 985 to Appel, U .S . Patent 1 , 904, 373 to Ke pthorne, and U .S . Patent 1 ,967, 167 to Weis .

Sti ll another class of engines has been mentioned as having the poten¬ tial for providing efficient and non-polluting engines for use in vehicles and the like, namely, Stirling engines, which are based upon the 1816 in¬ vention of Reverend Robert Stirling of the Church of Scotland. An excel¬ lent description of Stirling engines may be found in the August, 1973 issue

of Scientific American (Volume 229, No. 2, beginning at page 80) . As is clearly pointed out in the Scientifi c American article, Stirling engines have been characterized as external combustion engines — for the reason that the heat source is external of the working chambers of the engine. So far as is known, there has never been any suggestion of a construction in which the operating principles of a Sti rling engine could be applied with an internal combustion device . Because of the unique arrangement of eie- ments which are hereinafter described, an internal combustion Sti rling engine is obtainable — as well as an Otto and/or Diesel cycle engine. ^' Disclosure of Invention

In its most simple embodiment, the invention includes a housing with a generally spherical compression chambei — in which a generally disc- shaped rotor rotates at a substantially uniform speed. Connected to the rotor plate for rotation therewith is a separator plate; and the separator plate is also hingedly connected to the rotor plate, so that the separator plate may change its relative position with respect to the rotor plate while both plates are rotating within the spherical cavity . Appropriate ports are opened and closed (by vi rtue of being uncovered and subsequently

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covered) at times which are effective to admit a fresh charge of gas and

subsequently discharge a compressed quantity of gas. The addition of appropriate ignition means causes the device to operate like an internal

combustion engine in one embodiment, or as a pump or compressor in other embodiments .

In a complex embodiment of the invention, gases are transferred ex¬ ternally of a first, large spherical chamber through a second, smaller

spherical chamber, both of which have rotors as described above. The main rotor shafts of the two chambers are geared to rotate together but in opposite di rections . An ignition device such as a spark plug is placed in the small sphere, such that the sphere functions as a combustion chamber

and transfer valve for passing gases from a compression compartment to an expansion compartment in the larger sphere. The ratio of the large sphere's compartment displacement to the small sphere's compartment displacement is the compression ratio of the engine.

In another complex embodiment, a housing has two spherical chambers which are in communication with each other at appropriate times . Suitable heat exchangers are provided in the communication paths between appro¬ priate compartments of the two spherical chambers . One of the two cham- bers is smaller than the other, and the main shafts of the two rotors are co¬ axial; the smaller spherical chamber serves the function of a transfer valve between compartments of the larger spherical chamber. The two differ¬ ently sized spherical chambers and the connecting passages (with thei r

associated heat exchangers) are effective in providing the four states of a gas in a classical Stirling engine, namely: 1 ) cool and expanded; 2) cool

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and compressed; 3) hot and compressed; and 4) hot and expanded . Of

course, the chemical transformation of air and/or an air/fuel mixture dur¬ ing one of the "cycles" described herein should make it apparent to a very critical observer that this engine should not properly be called a pure Stirling engine. However, it is believed that the construction disclosed herein is sufficiently close to the classical definition as to justify calling it

a Stirling engine which is distinguished by operating with internal com- bustion of an air/fuel mixture. And, it does not seem to be unreasonable to refer to the construction, for convenience, as simply a Stirling engine. Indeed, if a person does not refer to this particular version of the engine as a Stirling engine, then he is left with the problem of how to classify it — because it certainly is not like well known Brayton, Ericsson , Otto or Diesel engines . So, if it is not sufficiently akin to pure Stirling engines as to be categorized with them, then someone must create a new label and definition for this innovative species of engines . Brief Description of Drawings

Figure 1 is a perspective view, partially sectioned, of an exemplary pump showing elements of the invention in an assembled condition;

Figure 2 is a fragmentary view of two of the primary moving parts that are shown in Figure 1 , and being shown in the same relative position ^" as the parts in Figure 1;

Figures 3-10 are views simi lar to Figure 2 but showing the parts in the respective positions they would occupy during continued rotation of said parts; Figure 11 is a partially sectioned top view of an apparatus simi lar to

Figure 1;

Figure 12 is an exploded view of an exemplary apparatus like that shown in Figure 1;

Figure 13 is a partially sectioned perspective view of a construction

like that shown in Figure 1 but configured expressly for use as a positive displacement, internal combustion engine;

Figure 14 is a top, plan view of a main rotor for use in an embodi¬ ment of the invention using internal transfer between certain compartments; Figure 15 is a fragmentary cross-sectional view of a portion of the

rotor shown in Figure 14;

Figure 16 is a cross-sectional view of a rotor taken in the plane indicated by lines 16—16 in Figure 14;

Figure 17 is a diagrammatic i llustration of the functions of four com¬ partments of an engine at any one instant, with the reference numerals shown in this figure being used to refer to structure that is shown in other figures;

Figure 18 is a somewhat schematic, cross-sectional view, in eleva¬ tion, of a dual-sphere embodiment of an 1C engine, wherein external trans¬ fer of fluids between the two spheres is uti lized; Figure 19 is a view similar to Figure 18 wherein the rotors associated with the two spherical cavities are coaxial, and heat exchangers are em¬ ployed to achieve the characteristics of a Stirling engine; and

Figure 20 is a top plan view , partially sectioned, showing an exemplary spatial arrangement of two spherical cavities like those shown in Figure 19.

Best Mode for Carrying Out the Invention

To begin, it wi ll perhaps be best to describe a very simple construction

— namely, a pump — which wi ll provide a foundation for the more complex description which is to follow . More specifically, a pump will be described

which is adapted to receive power at its main rotor shaft and deliver a working fluid through an exit port. Referring initially to Figure 1 , an

exemplary pump 10 includes a rigid body 12 having a generally spherical cavity 14 therein. Also, there is at least one opening into the cavity 14 for accommodating a support shaft 18 for a generally disc-shaped rotor 20. The shaft 18 will typically be adapted to receive rotary power from some source (not shown) , so that it may cause rotation of the rotor 20 about a first axis 22. Porting means , such as inlet port 24 and outlet port 26, cooperate with other ports (which cannot be readily seen in this view) for admitting and venting working fluids to and from the spherical cavity . A separator plate 28 is movable with respect to the rotor 20 about a second axis 30. The separator plate 28 also rotates with the rotor (about the first axis) , and cooperates with the rotor to define compartments of varying size during rotation of the rotor. One way in which the separator plate may be conveniently caused to move with respect to the rotor 20 is to provide an equitorial groove 32 in the cavity wall, in such a way that a plane is defined by the equitorial groove which neither encompasses nor is perpendicular to the first axis 22. By providing at least one pin 34 — and preferably two diametrically opposed pins— rat the periphery of the plate 28, and causing the pin (s) to ride within the grove 32, rotation of the rotor 20 will inherently cause the connected separator plate 28 to osci llate

with respect to the rotor . To better explain the compartments which vary in size during rotation of the rotor 20, Figures 2-10 wi ll now be discussed . In Figure 2 the housing has been removed, for clarity, and the rotor 20

is shown generally horizontal and the separator plate 28 is shown general- ly vertical . This is not a usual beginning phase of any typical pumping operation, but it is a convenient point at which to momentari ly interrupt motion of the elements 20, 28 for examination . A fi rst segment of the spherical cavity within the housing is designated as compartment 40; and the complementary spherical segment (on the opposite side of separator plate 28) is designated as compartment 42.

In Figure 3, the rotor 20 has been rotated 45° about axis 22 from its position in Figure 2; and, because the pins 34, 36 must ride in the equi¬ torial groove, they cooperate to guide or restrain separator plate 28. The longitudinal axis of arrow 38 lies in the plane defined by the equitorial groove 32. Thus , rotation of rotor 20 about its axis has caused the sep¬ arator plate 28 to shift its position (or "move") with respect to the rotor; still, the two elements 20, 28 may be said to rotate as a unit about axis 22. It wi ll also be seen that the compartment 40 indicated in Figure 2 has now become much larger, whi le the adjacent compartment 42 has become correspondingly smaller. When the separator plate 28 has a size (diameter) •which is substantially the same as that of the rotor 20, there wi ll be four compartments formed by the combination of the rotor and separator plate.

Hence, in addition to compartments 40, 42, there will be two companion compartments on the reverse side of the rotor 20; and, these other two

compartments constitute essentially mi rror images of the fi rst-named

compartments, progressively increasing and decreasing in size — in tandem with compartments 40, 42.

In Figure 4, the relatively movable rotor 20 and plate 28 have reached a position where the compartment sizes are at thei r maximum and minimum, respectively . That is , the face 44 on the rotor 20 is in its most-removed position with respect to face 48 on plate 28, and the compartment 40 bet¬ ween faces 44 and 48 may be considered to be in its most "open" condition . Continued rotation of rotor 20, arriving eventually at a position represent¬ ed by Figure 5, causes the faces 44, 48 to begin to approach one another again. Thus , compartment 40 is beginning to close and compartment 42 is beginning to open . The relative positions of the separator plate 28 and rotor 20 during continued rotation of the rotor are shown in Figures 6-10. Referring again to Figure 1 , the pump 10 preferably has at least some means for controlling the admission of a working fluid through the porting means 24, 26 at appropriate times . In its simplest embodiment, the rotor 20 and the separator plate 28 may be used to selectively separate the various ports at appropriate times, such that fluid which is captured bet¬ ween certain approaching faces wi ll be forced through a desired port and blocked from other ports . Thus , in an embodiment where rotary power from an external source is applied to shaft 18, the work done by. the rotor naturally produces the expulsion of a working fluid from certain compart¬ ments at particular times . In another embodiment, rotary power is gener¬ ated within the housing by the controlled ignition of an air/fuel mixture and the subsequent expansion of gases within appropriate compartments .

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The preferred manner of causing the separator plate 28 to osci llate with

regard to the rotor 20 has been generally described as a combination of an equitorial groove and two coplanar pins that ride within the groove. More

precisely, the preferred construction includes an equitorial groove in the cavity wall as described above, and a ring 64 which is sized to fit snugly in but sti ll rotate freely within the groove . Planar thrust bearings , repre¬ sented by the fragmentary showing of bearing 66, serve to transfer thrust from separator plate 28 to the housing 12. A compression seal 68 is also advantageously provided on each side of the ring 64 — interiorly of the adjacent thrust bearings . The groove, incidentally, is ideally established by providing a shallow spacer ring 60 between two body sections 13A, 13B having inclined faces; the body sections are oriented so that thei r inclined faces are juxtaposed, and bolts or the like hold the ring 60 in place bet¬ ween the sections 13A, 13B . It should be apparent that such a design for the body sections 13A, 13B wi ll obviously foster ease in the assembly of the various elements of the construction, and it wi ll also simplify the manu¬ facture of many of the parts shown herein.

The ring 64 is engaged with the separator plate 28 at two diametrically opposite points along the periphery of the plate by the pins 34, 36. As stated earlier, when the rotor 20 is rotated, the separator plate 28 is caused to twist because pins 34, 36 are constrained to remain in the plane of the ring 64. The uniformity with which the separator plate 28 turns or "twists" depends to a substantial degree upon the angle which the plane of the ring 64 makes with respect to the first axis 22. If the angle A shown in Figure 11 is as large as 90°, then rotation of the separator plate 28 wi ll

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be exactly the same as the rotation of rotor shaft 18, which would produce

a very smooth action but would provide no change in the size of the com¬ partments between the rotor and the separator plate. Hence, no beneficial work could be realized from such a device. The other extreme for the

angle A is 0°, which produces an essentially jammed condition wherein the parts wi ll not turn . Obviously, then, an angle A_ somewhere between

0 and 90° is desirable; and, in fact, an angle of about 30° seems to offer particularly desirable advantages , so it may be called a preferred angle. A few general comments can be made about the angle A _^ . First, a small- er angle provides a larger effective volume (i .e. , effective displacement) in a given sized spherical chamber. Also, a smaller angle A produces greater torque — when a particular construction is being operated as an engine instead of a pump, because there is a longer "stroke" and more leverage. However, a smaller angle A _^ also produces greater variation in the angular velocity of the trust, ring as the rotor turns; conversely, an angle A _^ of 90° would produce no variation in the thrust ring angular veloc¬ ity . Perhaps it should also be noted that an angle A _^ of 45° provides the same mechanical advantage when the device is being externally driven {in the manner of a pump) as it is when it is operating as an engine (from ex- panding gases, etc. ) .

Referring next to Figure 12, a construction is shown (in an "exploded" view) which fosters ease in assembly and which also includes some of the various sealing elements that would conceivably be desirable between the moving parts. As with the earlier-described rotor, the rotor 20A rotates about axis 22; and said axis both extends through the center of the rotor

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and lies in a plane that encompasses the rotor. As shown in this figure,

the rotor 20A includes two generally wedge-shaped segments, with the

thin portions of the two "wedges" facing one another. The wedge-shaped

segments are separated by a hub 21 having a generally barrelled shape

whose longitudinal axis 30 is perpendicular to the rotor's axis of rotation 22. The hub 21 has journals 50, 52 which are adapted to receive bearings

54, 56 — which are in end caps that form parts of separator plate 28. In this

embodiment the separator plate 28 is divided into two confronting parts which, because of their appearance, can be aptly referred to as yoke mem-

bers 70, 72. Connecting pieces 74, 76, each having an arc-shaped exterior

surface, are sized to mate with the yoke pieces 70, 72 and thereby form the

disk-shaped separator plate. Bolts 58A, 58B , 58C, 58D engage threaded apertures in the right and left yokes 70, 72 in order to hold the yokes and

connecting pieces 74, 76 securely together. Seals are advantageously provided in order to produce efficiently seg¬ regated compartments within the spherical chamber. Left seal 78 is pro¬ vided with four elongated "fingers" which fit snuggly within complementary grooves in left yoke 70 and connecting pieces 74, 76. A right seal (not shown) engages similar grooves on the other side of the separator plate .

Of course, the lengths of the depending fingers are such that distal ends are essentially touching when the left and right seals are installed and the

various pieces are assembled and bolted together. Interior sealing between

separator plate 28 and the barrel-shaped hub 21 is accomplished by an arc-

shaped seal 80 which is captured between appropriate grooves in the yoke

members and the hub . A spring 82 constantly urges the seal 80 toward the

hub 21 in order to ensure intimate contact therewith. Only one of the arc- shaped contacting seals 80 is shown above the hub in Figure 12, but a

corresponding seal would be provided below the hub . In an equivalent

manner, arc-shaped seals represented by interlocking seal members 84A,

84B fit in grooves in the rotor's peripheral surface and provide a tight seal with the interior of the spherical cavity , it is probably appropriate to em¬ phasize here that ail of the described sealing members have a continuous wiping relationship with their respective cooperating surfaces, and they do not change their relative angle of contact during rotation of the parts . In other words, each sealing member is always perpendicular to the con¬ fronting portion of the mechanism, and does not exhibit the varying incli¬ nation that is typical with some rotary devices . Lubrication of the various seals may be accomplished by introducing a lubricant into the gases prior to their entry into the respective compartments, or by the di rect convey- ance of a lubricant through passages in the housings and rotors . Such a network of passage has not been shown in the drawing in the interest of simplicity; but such passages are well known to those ski lled in the art.

Referring sti ll to Figure 12, the separator plate 28 — like the rotoi — has four faces which are generally defined by two intersecting planes; and those two planes intersect one another at essentially the center of the ^" separator plate. Thus, the confronting faces of the rotor and separator plate are shaped so that they closely match one another when they are brought to a point of touching or nearly touching one another. A distin¬ guishing characteristic of the apparatus disclosed herein is that the re- spectively confronting faces can be brought to a position of contact

throughout essentially all of thei r area — such that the volume of a compart¬ ment which is defined by the space between two confronting faces can be

made to be essentially zero. As for the maximum compartment size, theo¬

retically it may be as much as one-half of the volume of the spherical cavity . As a practical matter, the thickness of a rotor and the necessity to provide a power transfer shaft of a practical size causes a maximum compartment size to be on the order of one-thi rd the volume of a sphere whose diameter is the same as the diameter of the rotor.

The employment of a rotary mechanism as an internal combustion engine is accomplished by providing a means for transferring the gas that has been compressed in one compartment to a compartment on the other side of the separator plate. Such a transfer can take place either enti rely within the spherical cavity or externally of the cavity through an auxi lliary valving mechanism . To illustrate the internal transfer technique, reference will now be made to Figure 13. The engine 110 includes a rigid body 112 having therein a generally spherical cavity 114. A generally disc-shaped rotor 120 is mounted for rotation within the spherical cavity 114 about a fi rst axis 122. As with the previously described pump, a separator plate 128 is connected to the rotor 120 for rotation therewith about the first axis 122; additionally, the separator plate is movable with respect to the rotor about a non-parallel second axis 130. In the preferred embodiment, the separator plate 128 and the rotor 120 are simi larly sized, and they are hinged at essentially their mid-points — such that four compartments are formed by the relatively movable separator plate and the rotor. Additionally there is provided a means for causing the separator plate

128 to move relative to the rotor 120 so as to define compartments of con¬

tinually varying size during rotation of the rotor. The preferred means for causing the desired relative motion includes an equitorial groove in the cavity wall, which groove defines a plane that neither contains the first axis nor is perpendicular to the first axis. There is also provided a struc¬ ture for essentially "connecting" the separator plate and the equitorial groove at two diametrically opposed points on the periphery of the separa¬ tor plate. The preferred structure includes a ring which is sized to fit within the groove and rotate therein . The ring has two cylindrical bores for receiving two pins 134, 136 that move with the separator plate. The pins 134, 136 need not be fixed to either the ring or the separator plate, but they must be captured so as to foster pivotable movement between the ring and the separator plate. At the appropriate time, when the rotor and the attached separator plate rotate, the ring is drivingly moved around the equitorial groove.

Transferal of gases within the engine 110 is. accomplished by providing a longitudinal and cylindrical bore within the main shaft 118; and, within this bore is fitted a hollow tube 139 which is aptly called a transfer tube. Referring additionally to Figure 14 (which is a plan view of the rotor 120) , the tube 139 has an inlet port 141 and an outlet port 143, both of which are relatively long and both of which are oriented with their long sides ex¬ tending in a direction that is generally parallel to the longitudinal axis of the transfer tube . The precise size (area) and shape of a given port open¬ ing wi ll naturally be established so as to "tune" a transfer tube to the other parameters of the engine, including the engine's rotational speed,

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etc. Besides being longitudinally spaced, the two transfer tube ports 141 , 143 are not radially aligned; and by virtue of being oriented about 90°

apart, they become aligned with rotor ports 121 , 123 at different times . Figure 14 shows rotor port 121 which is periodically aligned with inlet port 141 and functions like a valve in that it rotates and intermittently pass¬ es compressed gas into the static transfer tube 139. Actually, the port 121 is formed by a slot that extends all the way through the rotor 120, which

slot is closed by the transfer tube . When the rotor 120 turns, it period¬ ically causes one "end" of said slot to be aligned with the static port 141 — thereby justifying the categorization of the end of the slot as a "port" . Of course, this alignment of static port 141 with the slot in rotor 120 wi ll occur once every 180 of rotor rotation, as first one compartment and then another compartment (on the opposite side of the rotor) comes into alignment with the port 141. The duration of any communication between static port 141 and rotating port 121 wi ll normally be approximately 90°, and cessation of the alignment will normally occur at minimum compartment volume.

Also clearly shown in Figure 14 is port 123, which is periodically aligned with outlet port 143 in the transfer tube, venting gases into one of the four compartments for subsequent expansion as a part of the delivery of power by the engine . Additionally visible in Figure 14 is a shallow ^' recess or depression 125 in the otherwise planar face of the rotor, which recess extends outwardly from both sides of the port 123. As wi ll be more fully explained hereinafter, the combustion of gases within the adjacent compartment is fostered by this recess 125, which contributes its volume to the volume of the transfer tube 139; it is the compressed gases in these

two regions that are ignited by an appropriate ignition device. In ac¬ cordance with custom, the combined volumes of the transfer tube 139 and the recess 125 would be called the combustion chamber.

Before concentrating again on Figure 13, it will perhaps be appro-

priate to di rect at least some attention to Figures 15 and 16, and to discuss the ignition of gases in this particular embodiment of an internal combus¬ tion engine. The planar cross-sectional view of the rotor 120 illustrated in Figure 15 shows very clearly that the slot which produces the port 121 passes through the rotor, as does the slot that creates the port 123. Also shown in the bore of the rotor shaft is stator tube 147 (Figure 13, secured to the housing 112) , but the hollow transfer tube 139 has been omitted — for clarity .

Figure 15 also shows mounted within the stator tube 147 a nozzle 151 which is intended to represent a fuel injector that could be used as an integral part of the engine. Because such fuel injectors are well known , it is not believed necessary to go into extensive detai l as to the design or operation of such devices . Thus , it Is believed to be sufficient to simply say that, in accordance with this design, such an injector could be posi¬ tioned as shown in order to introduce fuel under pressure into the com- pressed gas in the transfer tube 139 .

Figure 16 shows an alternate ignition device for the engine in the form of a spark plug 153 that is mounted within a stator tube 147 in a manner similar to the previously described fuel injector. While the elon¬ gated shape of the spark plug 153 may appear somewhat unusual to those who are familiar with conventional automobi le spark plugs , there is nothing

exotic about the operation of the plug; and only its elongated insulator

would distinguish it in any way from previously known spark plugs .

Referring again to Figure 13, the transfer tube 139 is shown as being

held in a fixed position within the engine by vi rtue of 1) being captured

within the cylindrical bore in the rotor 120, and 2) by being locked against unwanted rotation by the engagement of intermeshing teeth or lugs 155, 157 on confronting ends of the transfer tube and the stator tube. While the

scale of the drawing does not permit i llustration of the tolerances with re¬ spect to lugs 155, 157, they have a somewhat loose fit. And, because the two tubes 139, 147 are designed as two distinct members, the transfer tube 139 has the ability to move slightly — in response to the pressurized gas being pushed into port 141 — in an upward di rection (as seen in this particular figure) . This slight upward displacement of the transfer tube 139 promotes a seal between the outer surface of the tube and the confining walls of the bore; concentric seals around tube 139 are also provided.

Another advantage of the two-element tube design is that optimiza¬ tion of material selection is permissible, with a high temperature alloy (i .e. , a material commonly used in exhaust valves) being used for the transfer tube 139, and a more malleable or easi ly machined material being used on the stator tube 147. One reason that it would be particularly nice for the "outer" end of the stator tube 147 to be easi ly machineable is that this would make it easier to bui ld an integral gear into the tube 147 — which would be useful in optimizing a scavenging function that is dependent upon the orientation of the tube 139, as explained below. First, it should be remembered that the exhaust port 160 in the

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chamber wall wi ll be open and one of the engine's four compartments will

be exhausting spent gases immediately prior to admitting a fresh charge of compressed gas through stator port 143. When it seems desirable, open¬ ing of the port 143 into the compartment above the rotor 120 can be made to

occur just slightly before the closing of exhaust port 160; this will promote a scavenging effect as the Incoming (compressed) charge assists in sweep¬ ing the last of the spent gases out of the exhaust port. Of course, there should be close correlation between the closing of exhaust port 160 and the opening of port 143, so that there will not be an inordinate loss of freshly compressed gas . But, once a decision has been made with regard to the location of exhaust port 160 and/or any valving associated with that port, the most reasonable way to thereafter influence the desired cooperative in¬ teraction between stator port 143 and exhaust port 160 is to rotate transfer tube 139. This can be accomplished by rotating tube 147 which is engaged with tube 139, thereby adjusting the time of alignment between stator port 143 and rotor port 123. By temporari ly loosening the bolts 162 that extend through slots in the flange 164, and then slightly rotating the flange about the axis 122, the relative times at which the respective ports 123, 143 come into alignment is easily affected. If the engine 110 shown in Figure 13 is to be operated at only a single speed, the optimum alignment of the transfer tube 139 can be set and bolts 162 securely tightened . However, if the engine is to operate at a variable speed, a new factor takes on some significance, namely, the amount of time that it wi ll take for the exhaust gases to be physically removed from the compartment which is adjacent exhaust port 160. At

- 21 - ^{' •} . : high operating speeds, it will likely be desirable to have port 143 open

somewhat earlier than at low speeds , in order to let more incoming gases

assist in pushing out the spent gases . Therefore, a transfer tube 139

whose position is continuously variable can offer distinct advantages; and,

machining or affixing a gear on the outer end of tube 147 (in lieu of the flange 164) wi ll provide the necessary means for continuously adjusting the relative position of the transfer tube 139. Such a gear could be keyed to tube 147 so that it would be oriented similarly to accessory or drive gear 166 which is keyed to rotor 120. Because speed governors for engines are so well known, and because changing the orientation of tube 139 by use of a gear would be simi lar to the use of many speed governor mechanisms, it is believed that those ski lled in the art wi ll recognize how this can be accomplished without further description. Of course, a lever or other structural element could also be used instead of a gear to turn tube 147, in a manner analogous to the way that a vacuum advance is used . to slightly rotate a distributor in many automobile engines .

Referring still to Figure 13, the housing for the engine has two clearly discernable ports in the spherical wall that defines the engine cavity . Port 159 (in the top, left-hand corner of the spherical cavity) is in communication with a compartment that is expanding; and, this port con¬ stitutes the inlet port through which fresh air or an ai r/fuel mixture is being drawn into the engine . Exhaust port 160 on the opposite side of the separator plate 128 is also open at the same time that port 159 is open; and, spent gases are being expelled through port 160. Below the rotor as it is depicted in Figure 13 are the remaining two compartments (on either side

of the separator plate 128) ; the "left" compartment is involved in com¬ pressing a previously admitted charge of fresh gases, and the "right" com¬

partment contains gases that are expanding as a result of the immediately

preceeding ignition . The respective functions of the four compartments of a four-cycle engine are shown diagrammatical ly in the four quadrants of Figure 17. Of course, the compartment that is shown as being involved in the compression of a given charge of gas wi ll soon change places with the upper compartment, and then wi ll be involved in the ingestion of another charge of fresh gas . Simi larly , the compartment that is indicated as being momentarily involved in expansion of burning gases wi ll soon be involved in the expulsion of these fully expanded gases; they wi ll then be referred to as exhaust gases . One way of describing the apparatus is to say that two of the four compartments are dedicated to the ingestion of fresh gas and the remaining two compartments are dedicated to the expulsion of ex- haust gases; and, the transfer tube that extends through the rotor serves as an internal passage between the two different kinds of compartments, at appropriate times.

It is perhaps worthy of mention at this time that the engine operation which is illustrated by Figure 17 includes the ignition of an air/fuel mix- ture every 180° of rotor rotation . That is, power is realized in a sym¬ metrical fashion by the expansion of burning gases every time the rotor turns 180°. As much as anything else, this characteristic of the engine being disclosed herein constitutes a distinguishing feature in com¬ parison with prior art engines such as the one disclosed in U .S . Patent 3, 877, 850 to Berry (which has two ignitions separated by only 90°,

followed by 270° during which no ignition takes place) .

Turning next to another embodiment of the engine, reference will

now be made to Figure 18 — which i llustrates a dual-cavity engine in which gases are transferred between certain engine compartments through an external arrangement of conduits, etc. Because of the extensive descrip¬ tion and illustration with regard to the previous embodiment, it is believed that it is now adequate to disclose this particular construction in a some¬ what diagrammatic form — with it being understood that the same kinds of seals, bearings, etc. , that were described with respect to the single- sphere embodiment could also be used in this dual-sphere embodiment. The engine 210 comprises a body 212 which has two distinct and slightly separated spherical cavities 214, 216, with the first cavity being larger then the second cavity . As with engine 110, this engine has a rotor 220 mounted for rotation within spherical cavity 214 in a sealing fashion, so as to divide the cavity into two hemispherical compartments . A separa¬ tor plate 228 is mounted for rotation with the rotor 220, and it is also adapted for osci llation about an axis which lies in the central plane of the rotor; such osci llation is achievable by use of an equitorial ring of the kind shown in Figures 1 and 11 , etc. As with the earlier-described em- bodiment, the separator plate 228 produces four variable-volume compart- ' ments during rotation of the rotor. If desired, each of these four variable- volume compartments may be reduced to essentially zero volume at the time that the separator plate 228 momentari ly comes to a position of contact or near contact with the rotor 220. An extention of the rotor shaft 218 (to the left of the rotor in Figure 18) may be uti lized as the power output shaft of

the engine; and another extension (to the right of the rotor 220) is ad¬ vantageous ly uti lized to synchroni ze the respective activities in chambers in 214, 216.

An inlet port 241 is provided in the wall of body 212 for the purpose of drawing in a fresh charge of air into the spherical cavity 214 during the time that the separator plate 228 is moving in a clockwise di rection, as seen in Figure 18. That is , when the compartment immediately adjacent inlet port 241 is expanding, a fresh charge of ai r (or an air/fuel mixture) will be admitted to the engine. A means for introducing a combustible fuel into the engine 210 is shown diagrammatlcally as carburetor 221 , which is in communication with inlet port 241 . The carburetor 221 is not shown in any greater detai l, because it may be any of a variety of well- known devices for vaporizing the particular fuel that is to be burned . And, because it is believed that the engine disclosed herein can be made to ef- ficiently burn a wide variety of fuels, it wi ll be left to those skilled in the art to select a particular carburetor for whatever fuels are to be utilized. The body 212 also has an outlet port 243 through which compressed ai is removed from the first cavity 214, after it has been compressed between the separator plate 228 and the rotor 220. Compressed gases are then moved through external passage 245, which is connected to the intake port 249 of the small spherical cavity 216.

Rotor shaft 218 in the larger compartment 214 may be conveniently referred to as the main rotor shaft, because — for one reason — it is larger than rotor shaft 219 within cavity 216. Also, it is probably more expedient to obtain the engine's power output di rectly from that chamber where

burning gases wi ll be expanding and driving the rotor 220. Rotor shaft

219 is mounted so as to be parallel to main shaft 218, in order that rotation of the two shafts may be synchronized, as through the two i llustrated gears

224, 226 shown externally of the body 212. Of course, the direction of rotation of gear 226 will be opposite to that of gear 224, with the result that rotor shaft 219 will turn in a di rection opposite to rotor shaft 218. As a consequence, compartment 251 in small cavity 216 wi ll be contracting at the same time that compartment 231 in large cavity 214 is expanding in size. On the other side of small rotor 222 the compartment 252 wi ll be expanding at the same time that compartment 233 is contracting. Hence, the transfer of gases from compartment 233 through passage 245 into compartment 252 is fostered by interaction between rotors (pistons) 220, 222.

As with other engines, it wi ll normally be appropriate to ignite the air/fuel mixture at what amounts to top dead center (T .D .C . ) of the com- partment; so, ignition should occur when compartment 231 is at essentially its minimum volume, and the compartment 251 is at its maximum volume. This can be accomplished by locating ignition plug 256 (e.g . , a spark plug) so that it is in communication with cavity 216; and ignition wi re 257 pro¬ vides the electrical energy to plug 256 at appropriate times , in accordance with conventional practice. Thus , the small sphere 216 serves both as a combustion chamber and as a transfer valve — for passing gases from a com¬ pression compartment 233 to an expansion compartment 231 in the large cavity 214. In fact, the size of the "combustion chamber" essentially determines the compression ratio of the engine; that is, the ratio of the large sphere's displacement to the small sphere's displacement constitutes

OMPI

the compression ratio of the engine.

While other mechanisms could perhaps be uti lized to play the role of an "external" transfer valve and combustion chamber, the embodiment illustrated in Figure 18 is particularly advantageous . Also, it should be noted that two of the compartments in the small sphere 216 have not been described as being involved in the combustion process . This means that these two remaining compartments are available for other duties which might be of use in conjunction with the engine, such as pumping and/or "compressing" a fluid — as with a so-called supercharger. Referring next to Figure 19, an internal combustion engine 310 has a housing 312 with an internal cavity 314. A rotor 320 is mounted in cavity 314 for rotation with rotor shaft 318; and, separator plate 328 rotates with and osci llates with respect to the rotor, so as to establish variable- olume compartments within the cavity 314. Reduction in the volume of compart- ment 333 causes compression of any gases in said compartment, in the same manner as described with regard to device 110, etc. Working gases are present in compartment 333 by virtue of having been admitted to the engine through an inlet port 341 that draws in a charge of fresh air as the separator plate 328 moves away from inlet 341 . Subsequent rotation of the rotor wi ll cause the fresh charge of ai r to be physically translated within ^" the cavity 314 such that it is then in a position to be expelled from the "lower" compartment 333 through outlet port 343. This outlet port 343 is in communication with a heat exchanger 345, which may be conveniently referred to as a cooling passage because the compressed charge of air which has been expelled from compartment 333 is cooled as it passes to a

second and smaller cavity 316. Concurrent compressing and cooling of the

ai r which is being expelled from compartment 333 obviously reduces the

work which must be done in compressing said ai r. After the ai r has been

fully compressed and is moving through the system, a second heat ex-

changer 365 is uti lized to impart heat to the compressed (but cooled) air

before it is subsequently ignited. Using exhaust gases from a previous

cycle as the heating medium in heat exchanger 365, a particularly effica¬ cious arrangement of passages and structural elements produces a bene¬

fit with essentially no additional work — beyond that requi red to overcome friction. That is, all of the work to compress a given charge of gas has already been done when the gas is compressed in compartment 333; and

the subsequent heating of that gas in heat exchanger 365 requires no additional work. The construction thus fosters efficiency by salvaging at least some of the heat from the exhaust gases that otherwise would be lost

to the environment.

The mechanism associated with the small sphere 316 serves a double purpose. First, it serves as a means for segregating ai r in the cooling

passage 345 from air in the heat exchanger 365; secondly, the combination

of the rotor 322 and separator plate 330 function together as a transfer valve for moving gases . In this embodiment the two rotor shafts are co¬ axial , and the direction of rotation of the two rotors 320 , 322 are the same. So, compartment 373 is expanding at the same time that compartment 333 is

contracting; and gases are received in compartment 373 in a cooled and compressed state. Gases on the other side of small rotor 322 in compart- ment 375 are forced through outlet port 364 and through heat exchanger

365 — at the same time that a new charge of air is being admitted to com¬

partment 373. After absorbing heat in heat exchanger 365, the discrete charge of gases enters compartment 371 on the other side of the separator plate. Of course, compartments 371 and 375 are formed by partitioning a fixed volume with the separator plate 330; and the interior volume of the tubes in heat exchanger 365 is also fixed. Therefore, the total volume of compartments 371 , 375 and the inner passages of the heat exchanger 365 remains constant. Any heat added during, the transfer of gases from com¬ partment 375 to 371 is therefore an isometric process; and the temperature of the compressed gases can be increased without having to perform any new work.

The compressed and heated ai r which has been through heat ex¬ changer 365 then passes through port 368 (as the rotor 322 rotates) and into the combustion passage 380. In the preferred embodiment, the com- bustion passage 380 has both a fuel injection nozzle 382 and an ignitor 384 which is within the spray pattern of the nozzle; the ignitor 384 may be either a spark plug or a glow plug or an equivalent device.

The air/fuel mixture which begins to burn in the combustion pass¬ age 380 continues to burn and expand into compartment 331 . A relatively large volume in the combustion passage 380 wi ll cause a lowered "peak " pressure" during combustion, if pressures at the end of the expansion stroke are low. Therefore, a small combustion passage 380 is generally preferred. The mechanical advantage that exists because of the difference between the pressurized surface areas of large separator plate 328 and small separator plate 330 causes large compartment 331 to expand — which

provides the "power stroke" of the engine . Continued rotation of the rotor

will cause the lower compartment (which was full of expanding gases) to be translated to an upper position where the compartment is in communica¬

tion with exhaust port 337. That is, those gases which are shown at a given time as being present in lower compartment 331 will shortly there¬ after be in the position of the upper compartment which is identified as ex¬

haust compartment 335. The hot gases, now aptly called exhaust gases, are then forced through the hot side of heat exchanger 365 as the exhaust compartment contracts . As suggested in the drawing, the gas-to-gas heat exchanger 365 will be most beneficial if it is of the counter-flow type. Having yielded as much of their residual heat as is possible in the heat exchanger 365, .the gases are then vented to the atmosphere or some other apparatus . Of course, if the fuel which is to be burned in this engine is one such as hydrogen instead of a typical hydrocarbon fuel , the exhaust products coming out of heat exchanger 365 may consist of sub¬ stantial quantities of water along with waste gases .

A review of Figure 19 from a "systems" point of view should make it apparent that cool air has been brought into the large cavity 314 and com¬ pressed without allowing any substantial temperature increase, such that the air admitted to compartment 373 may be said to have experienced iso¬ thermal compression . Of course, this assumes that the efficacy of the heat exchanger 345 approaches the ideal . Next, the discrete charge of gas is heated while being kept at a fixed volume as it passes through the cool side of heat exchanger 365, where it absorbs heat; thus, the gas ex- periences isometric heating . The given charge of gas which is being

considered is then passed through the combustion chamber where it ex¬

pands at a substantially constant temperature, by virtue of the burning of a gas/fuel mixture within "the gas" as it passes into compartment 331 . Finally, the given charge of gas experiences essentially isometric cooling as it passes through the hot side of heat exchanger 365. (Again, this as¬ sumes that the efficacy of the heat exchanger 365 approaches the ideal; but this is not an unrealistic assumption, because the hot side of heat ex¬ changer 365 can be made as large as seems to be desirable in order to ex¬ tract the last practical quantity of heat from the vented charges of gas . ) Those skilled In the art wi ll recognize that these four phases constitute what is referred to as the Stirling cycle.

It is perhaps appropriate to mention here that maintaining a high temperature in the expansion gases (by controlling the fuel supply, etc. ) up to essentially the end of the expansion phase is quite tolerable with this construction . Unlike other internal combustion engines that discharge their spent gases into the atmosphere, this internal combustion engine makes use of the residual heat in the expansion gases, by transferring at least most of the heat to an incoming charge of fresh aii — through heat ex¬ changer 365. Referring next to Figure 20, the manner in which a dual-sphere em¬ bodiment of the invention may be configured is readily visible. The large and small cavities 314, 316 are positioned side by side, and they have re¬ spective rotors 320, 322 that are connected to a power output shaft 318 for rotation therewith; of course, in this particular embodiment, the two rotors are coaxial . Also easily recognizable in this top view of an

exemplary engine is the inlet vent 341 through which a charge of fresh ai r may be drawn into the large cavity; the exhaust vent 366 and the two par¬ allel rings 390, 392 are also clearly visible in the partially sectioned view .

Turning attention at this time to the two rings 390, 392, it should be noted that they have a character that is similar to that of a flywheel; but they differ from the conventional flywheel of an internal combustion engine in that they have a rotary velocity that is both variable and different from that of the power output shaft. The signi ficance of this wi ll perhaps be better understood after a brief review of conventional engine design practice.

With internal combustion engines of the type found in most auto¬ mobiles , trucks and fixed installations, torque is obtained by providing a mechanical link (or crank) between a variable-volume chamber and a power output shaft. When the chamber is at or near its minimum volume and ignition occurs , the pressure in the chamber is at its maximum; but the pressure falls off rapidly as the volume of the chamber expands, and it o wi ll have been greatly diminished by the time the crank is at 90 — where the crank has its maximum mechanical advantage . In other words, the peak torque from a given cylinder occurs well before the mechanical ad- vantage of the mechanism reaches its maximum — in contrast to a more near¬ ly constant pressure engine, such as the steam engine envisioned by Appel in U .S . Patent 826, 985. And because gases are concurrently being com¬ pressed in other "chambers" of a multi-cylinder engine, it is common for the net torque acting on the power output shaft to actually become negative in the latter stages of a given power stroke.

Rapid fluctuation of forces (and hence torque) acting on the many components of the drive train is harmful to those components , and extensive efforts are therefore routinely employed to reduce such fluctua¬ tions . One rather obvious technique is to employ multiple cylinders whose powerstrokes overlap, and the V-8 engine is perhaps the most well known example of this design approach . Another technique is to elongate the power stroke, and the Wankel engine is certainly a good example of this approach. And, of course, there is the technique that is probably more universally uti lized for many kinds of engines, namely, use of the common flywheel . Unfortunately, none of these design techniques have proven entirely successful .

The deficiency of the common flywheel is inherent in the way it is combined with a typical engine. When an engine's generated torque is at its highest level and it is operating under a constant load, that torque causes the rate of rotation of the power output shaft to increase; conversely, the rate of shaft rotation decreases when the generated torque is at its lowest level . The addition of a common flywheel moderates this variation somewhat, because of the "variable load" that is introduced by virtue of well-known inertial effects . Any effort by the pistons to increase shaft rotation requires an acceleration of the rigidly attached flywheel mass, thereby absorbing some of the energy that is produced at peak torque levels . When the generated torque level falls, the flywheel is slowed by the engine load; in this manner the flywheel returns back into the system some of the energy that was consumed in accelerating it. While such a system definitely has some merit, it should be noted that the system involves — and

indeed requires — the concurrent and equal acceleration and deceleration of

the flywheel and the power output shaft, because they are keyed or other¬

wise connected together.

An ideal energy storage and recovery system should deal with the

problem of shaft speed fluctuation; and, logically, energy should be stored during the first half of a power stroke and recovered during the second

half of the stroke — but the output shaft speeds should be left as nearly con¬

stant as possible. The construction disclosed herein, of course, does just o this. During the first 90 of constant mainshaft rotation after TDC, the o ring is caused to accelerate; and during the immediately following 90 of

constant mainshaft rotation, the ring is caused to decelerate. Thus, dur¬

ing that portion of an engine cycle when the torque generated by the engine

is relatively high, a portion of the engine's output is used to accelerate a rotating member (the ring) ; and the rotating member experiences an in- crease in its rate of rotation relative to the rate of rotation of the power output shaft. Later in a cycle, when the torque that is instantaneously being generated by the engine is relatively low , the rotational speed of the rotating member (relative to that of the power output shaft) is decreased; and energy recovered by vi rtue of said decrease is applied as torque that is acting on the power output shaft. In this manner, the variation in output

torque realized at the power output shaft is minimized . Of course, the mass of a ring (such as ring 64 which is clearly visible in Figure 12) , and the

way it is structurally coupled to the power output shaft, and the angle it

makes with respect to the power output shaft, will have some impact on the

degree of "match" between a given internal combustion engine and a pro¬ posed ring. Too, it will obviously be easier to select a complementary ring for an engine that is adapted to operate at a single speed — as compared with choosing a "compromise" ring for a variable speed engine. As soon as the torque characteristics of a given engine are established, it is be¬ lieved that those skilled in the art would be able to employ the teachings revealed herein to design a ring that would tend to "smooth out" those variations that are deemed to be the most troublesome. In designing an optimum ring, however, it must be kept in mind that the ring performs at least three major tasks: 1) it functions as a type of flywheel, in temporarily storing and then releasing energy; 2) it constitutes a power-transfer mecha¬ nism, assisting in the conversion of a fuel's heat of combustion into mechani¬ cal energy; and 3) it serves to "complete" the spherical cavity — by virtue of having its interiorly facing surface form an extension gf the static walls of said cavity .

While only certain preferred embodiments of the invention have been disclosed in detail herein, it should be apparent to those skil led in the art that modifications thereof can be made without departing from the spirit of the invention . Thus, any specific structure shown herein is intended to be exemplary and is not meant to be limiting, except as described in the

claims appended hereto.

O PI