US3624740A

US3624740A - Rotary piston internal combustion engine

Info

Publication number: US3624740A
Application number: US33619A
Authority: US
Inventors: Fredrik Jeremias Hogguer
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-05-02
Filing date: 1970-05-01
Publication date: 1971-11-30
Anticipated expiration: 1988-11-30
Also published as: DE2020882A1; FR2044756A1

Abstract

The rotary piston of an internal combustion engine has a geometrical configuration such that all lines through the axis of rotation of the piston are of equal length.

Description

United States Patent [72] Inventor FredrIkJeremlasI-logguer [50] FieldolSearch 123/807, Nleuw Loosdrechtsedlik 264, Netherlands 8.35, 8.41; 418/210, 240, 150 [21) AppLNo. 33,619 1221 Filed May 1,1970 1 Rekmmcfled 4s Patented Nov. 30, 1971 UNITED STATES PATENTS [3 1 Priorities Mas/2,1969 154,231 8/1874 Dietz 418 240x 3 Netherlands 1,033,514 7/1912 A1fo1'd.. 418/240 [3 6906731; 1,157,806 10/1915 Rixen 418/240 Dec-l9,l969.Nethrlands,N9-69l9089 1,944,956 1 1934 Thomas.... 4181240 2,215,873 9/1940 Gahm 418/240X 3,361,119 1/1968 COnOIly.... 41s/240x {54] ROTARY PISTON INTERNAL COMBUSTION ENGINE 8 Claims, 21 Drawing Figs.

[52] US. l23/8.07, 123/835, l23/8.41, 4181210, 418/240,418/150 [51] Int. Cl ..F02h 53/06, F02b 55/08 Primary Examiner-Allan D. Hemnann Attorney-Burns, Doane, Swecker 8: Mathis ABSTRACT: The rotary piston of, an internal combustion engine has a geometrical configuration such that all lines through the axis of rotation of the piston are of equal length,

PATENTEBRUV 30 I9" SHEET 01 0F 10 PATENTEUNUV 30 IBYI SHEET U20F10 PATENTEDunv 30 Ian 3, 24, 740

sum 03 0F 10 PATENTEnunv so IBYI 3, 524, 740

SHEET UUUF 10 PATENTEnuuv 30 I97] SHEET USUF 10 PATENTEUNHVSOIS?! 3,524,740

SHEET 070F 10 PATENTEDuuvaomn 3,624,740 SHEET U80F 10 ROTARY PISTON INTERNAL COMBUSTION ENGINE This invention relates to an internal combustion engine comprising an engine housing having a virtually right-circular cylindrical inner wall, a rotary, out-of-round, cylindrical, hollow piston within said housing, pairs of diametrically opposed slides guided in fixed parts of said housing for radial move ment and continuously in contact with the periphery of said piston to define sections of varying radial dimensions between said housing and said piston for different phases of the combustion process, the slides of each pair being interconnected by a diametrical coupling rod.

An engine of this kind, hereinafter referred to as of the kind described, is known, and has various disadvantages, the most important one of which is that the shape of the periphery of the piston makes it necessary for the coupling rods of the pairs of slides to be provided with a resilient member to ensure that the slides are always in contact with the piston.

It is an object of the present invention to provide an improved construction of the engine, thereby to overcome these and other disadvantages.

According to the invention, there is provided an internal combustion engine of the kind described, in which the crosssectional configuration of the peripheral wall of the piston is composed of two opposed quadrants of a circle having a common center in the axis of rotation of the piston and respectively having a larger radius R and a smaller radius r, said quadrants being connected by arcuate portions in the other quadrants, whose geometrical configuration is the locus of points to be found by drawing in one of the last-mentioned quadrants an auxiliary arc of a circle having a radius r and having its center in the radius bounding the larger of said firstmentioned quadrants and the quadrant in which the auxiliary arc is drawn, and at a distance R-r from the axis of rotation of the piston, drawing a diametral line R+r from each point of said auxiliary circle through the center of said first-mentioned quadrants, producing said diametral line to a second auxiliary circle in the opposite quadrant, said second auxiliary circle having a radius r and having its center in the other radius boundingithe larger of said first-mentioned quadrants and at a distance R-r from the axis of rotation of the piston and bisecting the line by which said diametral line is produced.

It is thus achieved that, as a result of the fact that all diametral lines through the axis of rotation of the piston, or, in space, the rectangular diametral planes of the piston are of equal length, the coupling rods may be rigid, provided their coefficient of expansion be equal to that of the material of the piston.

In one embodiment of the invention, in which the engine is of the four-stroke type, the inner periphery of the housing is defined by an inscribed right-circular cylinder having a radius of curvature equal to that of the piston sector having the larger radius of curvature, increased by the compression space.

In another embodiment of the invention, in which the engine is of the two-stroke type, the peripheral wall of the piston is of virtually uniform thickness throughout, and also has radial pairs of slides continuously in contact with its inner periphery, said slides being guided in slots of a centric, solid core in the form of a solid of revolution and fixedly connected with the housing of the engine, the inner periphery of the piston located closest to the center passing along the basis of said core, a thick, crescent-shaped disk, bounding one flat piston wall and extending halfway the other flat piston being secured to the peripheral wall of the piston, and having a centric right-circular cylindrical circumference, and except for the portion of the outer periphery of the piston which passes along the cylindrical wall of the housing, extends outside the other portions at the outer periphery of the piston, and is provided with an outlet, the flat piston surface at the upper side of the core having an inlet, the peripheral wall of the piston having a passage opening adjacent to, but trailing relative to, said outlet.

The invention will now be described with reference to the accompanying drawings, which, inter alia, illustrate a nonlimitative embodiment of a four-stroke engine and a twostroke engine. In said drawings,

FIG. 1 shows a diagram according to which both the outer circumference and the inner circumference of the piston according to the invention are designed, the latter circumference being of interest for a two-stroke engine;

FIG. 2-9 are diagrammatic showings of the internal combustion engine according to the invention, showing various phases of a four-stroke process;

FIG. 10-16 are diagrammatic showings of an internal combustion engine according to the invention, showing various phases of a two-stroke process;

FIG. I7 is an axial sectional view of an embodiment of a four-stroke engine according to the invention, with two pistons in the same position, namely, on the line XVII-XVII of FIG. 18;

FIG. 13 is a cross-sectional view of the engine of the line XVIIIXVIII of FIG. 17;

FIG. 19 shows, on a slightly enlarged scale, an axial section of an embodiment of a two-stroke engine according to the invention on the line XlX-X of FIG. 20, the upper half of the section being turned through relative to the lower half;

FIG. 20 and 21 are two cross-sectional views of the engine on the lines XXXX and XXIXXI, respectively, of FIG. 19.

Referring particularly to FIG. '1, both the four-stroke and the two-stroke engine require such a peripheral configuration of the piston that slides coupled pairwise by means of a rigid coupling rod are continuously in contact with the periphery of the piston, which coupling rod intersects the axis of rotation according to diametral lines. For this purpose, all diametral lines must be equally long. 7

The peripheral configuration of the hollow piston, generally indicated at l, and as viewed in cross section, is composed of two opposing quadrants of circles, namely

arcs

2 and 3, respectively having a larger radius R and a smaller radius r. The two

arcs

2 and 3 are interconnected by transitional arcs 4, 4'.

The configuration of the transitional arcs is determined by drawing two additional quadrants of a circles, namely rightand left-hand auxiliary arcs 5 and 5' having centers 0, 0' and a radius r and beginning at the ends of the arc with radius R. Virtually straight lines 6 connect the auxiliary arcs 5, 5' having a radius r with the arc 3.

On the horizontal diametral line 7 a line having a length R+r is set ofi' from the left-hand auxiliary arc 5' in FIG. 1 to determine point 8. The middle 9 of the line between 8 and the righthand auxiliary arc is a point of the right-hand transitional are 4. In the same way other points of the transitional arcs are determined by drawing other diametral lines and setting off R+r either from the left-hand or from the right-hand auxiliary arc.

The radii R and r in FIG. 1 concern the inner periphery of the wall of the piston.

The outer circumference of the piston wall can be designed in the same manner. It is simpler, however, when thickness d is set off radially outwardly from the inner arcs on the diametral lines. It follows that the thickness of the peripheral wall of the piston varies slightly and is greatest where the diametral lines intersect the circumference at right angles, in other words where they are perpendicular to the tangent at that point.

There will now follow a description of the four-stroke process of the engine according to the invention with particular reference to FIG. 2-9.

In FIG. 2-9, numeral 10 designates the inner circumference of the wall of the housing, sometimes referred to as the cylinder, and l the rotary piston. The inner circumference 10 is determined by an inscribed circle which in FIG. 2-9, owing to the diagrammatic representation largely coincides with the inner circumference.

The piston 1 has two

circumferential sections

2, 3 in the form of an arc of a circle concentric with the inscribed circle and respectively having a larger radius R and a smaller radius r. The arcs with radius R and r, respectively, define opposing sectors l1, 12, each having an angle at the center or axis of rotation 13 of 90. The two other sectors 14, naturally also have an angle at the center of 90, and are defined by transitional arcs 4, 4'.

The dot-dash lines in FIGS. 2-9 which define the sectors are the radial axes of movement of slides, two of which are shown diagrammatically at 16, 17. There are further four pairs of poppet valves in the housing, one

pair

18, 19 of which is shown, 18 being an inlet valve and 19 an outlet valve. Finally, there is shown a diagrammatic spark plug disposed between

valves

18 and 19.

In the quadrant between

slides

16, 17, which are continuously held in contact with the circumference of the piston, a complete four-stroke working process takes place, as a result of which the piston rotates in the direction of arrow 21.

The Z-shaped arrow 22 in FIG. 2 indicates ignition, it being supposed that there is a compressed explosive mixture in the quadrant between the piston and the inner wall of the housing.

Owing to the rotation of the piston, initiated by a starting motor not shown, the space 23 between the piston and the cylinder is increased (see FIG. 3) and expansion occurs". The forces generated are such as to move the arc 4 of the piston, this being the only member which can move in this space, and thereby to impart a rotary impulse to the piston.

The piston rotates further, whereby the concentric are 3-- the

arcs

4', 3, 4 can be regarded as the inner arc of a virtually crescent-shaped portion removed from an originally truly circular pistoncomes to lie opposite

valves

18, 19. Since further expansion is impossible, because the space 23 has reached its maximum volume, the outlet valve 19 begins to open (FIG. 4). Expulsion continues as the piston rotates along, thevalve 19 reaching its maximum opening in FIG. 5. Expulsion is promoted owing to the space 23 being decreased in size again by the are 41.

In the position of the piston of FIG. 6-which is equal to that of FIG. 2 and comparable to the outer dead center of a A crank connecting rod piston enginethe outlet valve 19 is closed and the inlet valve 18 begins to open.

As the piston I rotates further, the space 23 is again increased owing to the movement of transitional are 4 and when the inlet valve 18 is fully open, the inlet phase is accomplished, in other words, air or a combustible mixture-depending on whether the engine works according to the diesel principle or the Otto principle, is drawn into the space 23 (FIG. 7).

The end of the inlet phase is shown in FIG. 8, in which Figure the inlet valve is shown as being closed.

Finally, after the inlet valve-and also the outlet valve-are fully closed, compression occurs owing to the fact that the volume of the space 23 is again reduced by the transitional arc (FIG. 9). After one further quarter revolution ofthe piston, ignition can again occur, and the situation of FIG. 2 has been reached.

In FIGS. 29, arrows are shown at the valve rods, which indicate the direction of movement of the valves.

There will now follow a description of the two-stroke process of the engine according to the invention with reference to FIGS. 10-16.

FIG. 10 shows the beginning of the power stroke resulting from combustion or explosion which has just occurred owing to sparking from the spark plug 20. The combustion chamber 23 is bounded by the cylinder wall 10 of the engine housing, the circumferential surface of the piston 1 and two outward radial slides 16 and 17. The

slides

16 and 17 each form part of a diametrally coupled pair of slides, the slides on the opposite sides being designated by 16 and 17. The direction of rotation of the piston is indicated by arrow 21.

FIG. 11 shows the power stroke in full operation. Owing to the widening space 24, expansion of the combusted gases takes place. The power stroke ends when the outlet port has passed slide 16. This is shown in FIG. I2. The outlet port is arranged in a thick disk to be described hereinafter. The disk is connected with the circumferential wall of the piston I and is also active as a balancing weight. Consequently the outlet port 25 rotates along with the oubof-round piston wall.

In the position shown in FIG. 12, a passage opening 26 is located just before the slide 16as seen in the direction of rotation according to arrow 21-in the piston wall. Through the passage opening 26, the inner space 27 of the piston communicates with the outside chambers. Disposed in the inner chamber of the piston is a fixed, centrally arranged solid core 28, preferably in the form of a solid of revolution, which will be described later. This core defines with the piston wall a space 29, which is widened as the piston rotates, as shown in FIG. 13. The chamber 29 is further bounded by two radial slides 30 and 3I-disposed within the piston-which together with slides 30' and 31' respectively form an integral diametral pair of slides whose direction of to and fro movement coincides with that of the outward pairs of slides 16, I7 and 17, 17, respectively.

As shown in FIG. 13, the widening chamber 29 comes in communication with the inlet port 32 of the piston, which is in continuous communication with the air and fuel mixture inlet of the engine, to be described hereinafter. Accordingly, there is intake of fresh mixture within the piston.

In the position shown in FIG. 14, the piston has rotated so far that expulsion via port 25 from the space between the

slides

16 and 17 terminates, and intake into the spaces between the inward slides 30, 31, 30' via port 32 is in full progress.

An earlier intake of mixture in the space 33 between the wall of piston l, the body 28, and the

slides

30 and 31 which has been compressed in the restricted space 33 in FIG. l3 referred to as precompressionnow flows through the space 34 outside the piston wall and between the

slides

16 and 17, in which at the end of the exhaust period a lower pressure prevails than in the inner space 33.

In the position of FIG. 14, the outer space 34 begins to decrease in volume, and after the passage opening 26 has passed slides 17, 31 as shown in FIG. 15, compression is continued in this space. In the position of FIG. 13, in which the outlet port 25 and the passage opening 26 are between the

same slides

16 and 17, the mixture flowing via opening 26 into the space 34 will expell the remainder of combusted gases through the outlet port 26. This is the scavenging, which is of the greatest importance in a two-stroke engine.

In the position according to FIG. 16, compression outside the piston wall and intake within the piston wall continue until the position of FIG. 10 is reached, followed by ignition and explosion, initiating the power stroke.

The above described process takes place between slides 16 and 17 (30 and 31'). At the same time it takes place between slides 17 and 16' (3! and 30'), 16' and 17' (30' and 3I) and finally between slides 17 and 16 (31 and 30), that is, four times in one revolution of the piston. Accordingly, there are four power strokes per revolution of the piston without an interruption during the next revolution, as would be the case in a four-stroke engine with a single rotary piston.

There will now follow a description of an embodiment of a four-stroke engine according to the invention with particular reference to FIGS. 17 and 18. As appears from the description of FIG. 2-9, this engine works with two pairs of slides and four pairs of valves. In FIGS. 17 and I8 and 29, like parts are designated by the same reference numerals. In FIG. 17, the engine is provided with two equally positioned pistons I, I, rotating within a common cylindrical wall 10 of the engine housing. The rotary shaft consists of three sections, namely, shaft 13 which connects the two pistons, and the ends of which are provided with key grooves 35 which engage with countergrooves of hub members 36, the latter being connected with the facing piston walls 38 by means of bolts, of which the axes 37 are shown only. The piston walls 39 facing away from each other are provided with hollow taps 40 in an alignment with shaft 13, which taps constitute the two other sections of the shaft and are journaled in roller bearings 41 for rotation relative to outward cylindrical stubs 42 of the flat sidewalls 43 of the engine housing. I

The connecting shaft 13 is journaled in roller bearings 46 via bearing blocks 45 relative to the fixed partition wall 44.

The radially reciprocating slides cooperating with the peripheral walls of the pistons, one pair of which is shown connected by a connecting rod 47 with a slot 48 for the passage of shaft 13, are provided with means, such as flat springs (not shown) to urge them into sealing sliding contact with the peripheral wall of the respective piston in cooperation with a lubricant film and allowing for some clearance owing to thermal influences. A cross section of the other connecting rod 47, provided with a slot 48, is to be seen in FIG. 17.

The slides 16, 16' (and also the slides 17, 17', not visible in FIG. 17) are constituted by two

wings

49, 50, formed integrally with each other. Since connecting rod 47, 47' of each pair of slides engages slightly eccentrically, so that there is a risk of warping, the free ends of the wings are received in radial grooves 51 in the sidewalls 43 of the engine housing.

The poppet valves, of which in FIG. 18 the rods of the uppermost associated pair are designated by 18 and 19, are not shown in FIG. 17. The latter figure only shows the upper parts of the valve springs 52, spring cups 53, rockers 54, and tappets 55. The valves on the right-hand side and on the left-hand side have their axes respectively located in one plane perpendicular to the axis of rotation. However, the tappets of the inlet valves are axially offset relative to the tappets of the outlet valves through a distance 56, as a result of which all outlet valves and all inlet valves can each be operated by a

single cam

57, 58. In this way, all rockers are of equal length, resulting in an equal lifting height. (In FIG. 17, reference numerals 52 and higher are only shown in the right-hand half).

Cams

57 and 58 are arranged on a sleeve 59 freely rotatable on hollow taps 40. Sleeve 59 carries a gear wheel 60 at its end, which 2:1 with a sprocket 61 which with a sprocket 62 is keyed to an intennediate shaft 63. Shaft 63 is joumaled for free rotation in a case 64 extending radially from stub 42. The last-mentioned sprocket 62 engages with a sprocket 65 keyed to tap 40. This established the 2:1 ratio of the rotation of the cams and the piston.

On account of their eccentricity, the pistons are each provided with a balancing weight 66, cast in one piece with the piston. When the pistons consist of welded together pieces of metal plating the balancing weight may be a separate member.

In the zone of the valve cups, the inner wall of the cylinder is formed as a regular polygon 67, but axially beside the valve cup zone as a right-circular cylinder 68.

The slide compartments 70 are closed with covers 69, while the outwardly flaring tubes 71 in the hollow taps are designed for passing cooling fluid to the interior of the piston, which fluid can flow back through the annular space 72 between the tubes and the tap wall.

The two-stroke embodiment of the engine according to the invention will now be described in greater detail. This engine operates as described with reference to FIGS. -16. The reference numerals used in these figures are also used in FIGS. 19, 20, and 21 for designating like parts.

In the two-stroke rotary engine, the piston 1 is divided into two

axial parts

73 and 74, secured together. A ring 77 of radially varying thickness and right-circular cylindrical circumference is secured to sidewall 75the left-hand one in FIG. 19*of the part 73 by means of bolts 76, which ring surrounds the peripheral wall of the piston proper and acts as a balancing weight. The balancing weight has its largest thickness at 78.

In the part 73 of the piston (see FIGS. 19 and the inner surface of the circumferential wall of the piston is in cooperation with

internal slides

30, 31 and 31', the outer surface of the piston wall of part 74 being continuously in contact with

external slides

16, 16', 17 and 17'. Each internal pair of slides forms an integral piece by means of an

intermediate member

79, 79 half as wide as the slides, the external slides being pairwise coupled by coupling rods 47, 47' with threaded ends 80 and adjusting nuts 81, in the same way as in the four-stroke engine, and being guided in recesses 82, 82 in the central core 28, which in the subject embodiment is truly right-circular cylindrical.

This core extends axially throughout the two

parts

73, 74 of the piston and is secured to wall 84 of the engine housing bounding part 74 by means of a central tap bolt 83. An eccentrically disposed pin 85 restrains the core from rotating along with the piston.

Unlike the four-stroke engine of FIGS. 17 and 18, the twostroke engine has a single piston, composed of two

different parts

73, 74, and the

slides

16, 16', 17 and 17' are guided by round pins 86 formed integrally with covers 69.

The piston part 74 (see FIGS. 19 and 21), has no slide in its interior and its peripheral wall may have a thickness different from that of part 73, which is designed in accordance with FIG. 1. Part 74 is provided with some oil baffles 87, by means of which the wall is connected with central bushing 88. This bushing is journaled on an inwardly extending stub 92 of the wall 84 of the engine housing by means of a double-needle bearing with needles 89, and intermediate ring 91. The outside opening of stub 92, which has an intermediate wall 93 as a supporting surface for tap bolt 83, is closed with a cover 94, which is clamped against wall 94 by tap bolts 95. The sidewall 97 of piston part 74 is sealed by means of a flat, broad stationary ring 96.

The sidewall 98 of piston part 73 is connected with a shaft 100 by tap bolts 99, from which shaft the power of the engine can be taken off. Shaft 100 is journaled by means of needle bearing 101 in an inlet stub 102 with a lip 103, which forms part of the wall 104 of the engine housing.

At the flanged portion 105 of shaft 100, through which the tap bolts 99 are inserted, the shaft is provided with a central, stepped, blind bore 106, in which is arranged a ball bearing 107, which supports the stationary core 128 via a connecting member 108 secured to the bore by tap bolts 109.

FIGS. 19, 20 and 21 clearly show inlet port 32, passage 32 and outlet port 25.

The interior of the piston is cooled by a suitable fluid which enters through a supply tube not shown and can flow away through a discharge tube 110. For this purpose, ring 96, stub 92 and sidewall 97 of the piston are provided with passages 1 1 1.

112,113, 114, designate connecting pins, and 116, 117, 118, 119, 120, 121, 122 designate suitable sealing means. The latter may be gaskets, resilient plates or elastic insertions, grease gaskets, and like means.

The engine housing consists of two halves, each having a sidewall 104, 82 and a

circumferential portion

123, 124, formed integrally therewith, and through which extend long connecting bolts not shown.

In the four-stroke engine according to the invention, combustion takes place four times in succession during each revolution with one piston and, owing to the second piston, again four combustions during the next revolution. Each piston must perform one revolution for intake and compression.

In the two-stroke engine with one piston, there are four explosions during each revolution, that is, eight explosions in two revolutions. In this embodiment the volume of the inner space between the piston wall and the core is larger than the volume of the outer space between the inner wall of the housing and the piston wall.

It will be clear that modifications can be made in numerous minor details without departing from the scope of the invention.

lclaim:

1. An internal combustion engine comprising an engine housing having a virtually right-circular cylindrical inner wall, a rotary, out-of-round cylindrical, hollow piston within said housing, diametrically opposed pairs of slides guided in fixed parts of said housing for radial movement and continuously in contact with the periphery of said piston to define sections of varying radial dimensions between said housing and said piston for different phases of the combustion process, the slides of each pair being interconnected by a diametral coupling rod, in which the cross-sectional configuration of the peripheral wall of the piston is composed of two opposed quadrants of a circle having a common center in the axis of rotation of the piston and respectively having a larger radius R and a smaller radius r, said quadrants being connected by arcuate portions in the other quadrants, whose geometrical configuration is the locus of points to be found by drawing in one of the last-mentioned quadrants an auxiliary arc of a circle having a radius r and having its center in the radius bounding the larger of said first-mentioned quadrants and the quadrant in which the auxiliary arc is drawn, and at a distance R-r from the axis of rotation of the piston, drawing a diametral line R+r from each point of said auxiliary circle through the center of said first-mentioned quadrants, producing said diametral line to a second auxiliary circle in the opposite quadrant, said second auxiliary circle having a radius r and having its center in the other radius bounding the larger of said first-mentioned quadrants and at a distance. R-r from the axis of rotation of the piston, and bisecting the line by which said diametral line is produced.

2. An internal combustion engine according to claim 1 and operating according to the four-stroke principle, wherein the inner periphery of the housing is defined by an inscribed rightcircular cylinder having a radius of curvature equal to that of the piston sector having the larger radius of curvature, increased by the compression space.

3. An internal combustion engine according to claim 1, characterized in that a pair of radially movable valves is arranged between each pair of successive slides, said valves being preferably formed as poppet valves, and controlling an inlet channel and an outlet channel, the flat sides of the valve cups facing the piston forming with the adjacent parts of the inner circumference of the wall of said housing a polygon with which the inscribed right-circular cylinder is locally in contact.

4. An internal combustion engine according to claim 1, comprising two equally positioned pistons, and wherein each slide is duplicated to be simultaneously in contact with both peripheral walls of the piston, the connecting rods of each pair of slides engaging with the slides adjacent the middle, and extending between the two pistons said rods having a slot through which extends the rotary shaft connecting the two pistons.

5. An internal combustion engine according to claim 1, and operating according to the two-stroke principle, in which the peripheral walls of the piston is of virtually uniform thickness throughout, and also has radial pairs of slides continuously in contact with its inner periphery, said slides being guided in slots of a centric, solid core in the form of a solid of revolution and fixedly connected with the housing of the engine. the inner periphery of the piston located closest to the center rubbing along the basis of said core, a thick crescent-shaped disk, bounding one fiat piston wall and extending halfway the other flat piston wall, being secured to the peripheral wall and having a centric right-circular cylindrical circumference, and except for the portion of the outer periphery of the piston which rubs along the cylindrical wall of the housing, extends outside the other portions at the outer periphery of the piston, and is provided with an outlet, the flat piston surface at the upper side of the core having an inlet, the peripheral wall of the piston having a passage opening adjacent to, but trailing relative to, said outlet.

6. An internal combustion engine according to claim 5, wherein two radially inward pairs of slides and two radially outward pairs of slides are provided, which together with the inner circumference of the piston and the core define an intake chamber, a transition chamber and a precompressing chamber, and with the outer circumference of the piston and the cylinder wall define an intake chamber, and end compression chamber, and an expansion chamber, respectively.

7. An internal combustion engine according to claim 6, wherein the inward pairs of slides consist of a single integral rece. p 8. An internal combustion engine according to claim 5 wherein the volume of the inner space between the piston wall and the core is larger than the volume of the outer space between the inner wall of the housing and the piston wall.

* I i l

Claims

1. An internal combustion engine comprising an engine housing having a virtually right-circular cylindrical inner wall, a rotary, out-of-round cylindrical, hollow piston within said housing, diametrically opposed pairs of slides guided in fixed parts of said housing for radial movement and continuously in contact with the periphery of said piston to define sections of varying radial dimensions between said housing and said piston for different phases of the combustion process, the slides of each pair being interconnected by a diametral coupling rod, in which the cross-sectional configuration of the peripheral wall of the piston is composed of two opposed quadrants of a circle having a common center in the axis of rotation of the piston and respectively having a larger radius R and a smaller radius r, said quadrants being connected by arcuate portions in the other quadrants, whose geometrical configuration is the locus of points to be found by drawing in one of the last-mentioned quadrants an auxiliary arc of a circle having a radius r and having its center in the radius bounding the larger of said first-mentioned quadrants and the quadrant in which the auxiliary arc is drawn, and at a distance R- r from the axis of rotation of the piston, drawing a diametral line R+ r from each point of said auxiliary circle through the center of said first-mentioned quadrants, producing said diametral line to a second auxiliary circle in the opposite quadrant, said second auxiliary circle having a radius r and having its center in the other radius bounding the larger of said first-mentioned quadrants and at a distance R-r from the axis of rotation of the piston, and bisecting the line by which said diametral line is produced.

2. An internal combustion engine according to claim 1 and operating according to the four-stroke principle, wherein the inner periphery of the housing is defined by an inscribed right-circular cylinder having a radius of curvature equal to that of the piston sector having the larger radius of curvature, increased by the compression space.

5. An internal combustion engine according to claim 1, and operating according to the two-stroke principle, in which the peripheral walls of the piston is of virtually uniform thickness throughout, and also has radial pairs of slides continuously in contact with its inner periphery, said slides being guided in slots of a centric, solid core in the form of a solid of revolution and fixedly connected with the housing of the engine, the inner periphery of the piston located closest to the center rubbing along the basis of said core, a thick crescent-shaped disk, bounding one flat piston wall and extending halfway the other flat piston wall, being secured to the peripheral wall and having a centric right-circular cylindrical circumference, and except for the portion of the outer periphery of the piston which rubs along the cylindrical wall of the housing, extends outside the other portions at the outer periphery of the piston, and is provided with an outlet, the flat piston surface at the upper side of the core having an inlet, the peripheral wall of the piston having a passage opening adjacent to, but trailing relative to, said outlet.

7. An internal combustion engine according to claim 6, wherein the inward pairs of slides consist of a single integral piece.

8. An internal combustion engine according to claim 5 wherein the volume of the inner space between the piston wall and the core is larger than the volume of the outer space between the inner wall of the housing and the piston wall.