EP0328835B1 - Central shaft internal combustion engine with annular, opposing and solidly joined pistons - Google Patents

Description

The present invention relates to internal combustion engines with annular pistons, mounted in opposition and integral with each other, and with a central drive shaft, these engines using fuels such as diesel, kerosene, petrol, etc ... and may have two, four, six, eight cylinders or more.

Currently, commercial internal combustion type engines, fitted with conventional pistons, consume a large amount of energy to deliver a low useful power. This relatively low efficiency is mainly due to the design of the movable members constituted by the pistons, the connecting rods, the crankshaft and the valves. These conventional motors are further weakened by the large number of moving parts which they comprise and which are subjected to permanent and significant forces.

In order to remedy these drawbacks, it has already been proposed by English patent No. 11,027 an internal combustion engine operating with better fuel efficiency and considerably simplified construction.

The advantage of the engine proposed in this English patent resides in the elimination of the connecting rods and the crankshaft, which also makes it possible to obtain an engine whose speed of rotation is adapted to its use, without adversely affecting its performance.

In the internal combustion engine according to English Patent No. 11,027, two annular cylinders are each arranged on one side of a central corrugated member, and opening towards one another, and two annular pistons, mounted in opposition and each on one side of the corrugated central member, are mounted so that the head of each of the annular pistons slides with sealing in one of the annular cylinders. Thus, the reciprocating movement of the pistons is transformed into a rotary movement of the central drive shaft, which coaxially passes through the annular cylinders and pistons, by means of the corrugated central member, which is integral with the central shaft.

The annular pistons each cooperate with the corrugated central member extending substantially radially between them, relative to the axis of rotation of the central shaft, so that the pistons move away from each other simultaneously or approach each other simultaneously. The central corrugated member is a radial plate having a corrugated edge and each of the opposite faces of which receives the thrust of one of the pistons, by means of axial fingers, interposed between the base of each annular piston and the opposite face. of the corrugated radial disc, the axial fingers associated with one of the pistons occupying positions offset in the circumferential direction relative to the axial fingers associated with the other piston. In addition, these pistons have inward radial projections, which penetrate into a groove formed in the external periphery of the plate, in order to keep the pistons always in contact with the plate, while the thrust of the pistons is applied to the tray by fingers. These axial fingers are retained by radial pins which extend towards the outside by projections penetrating into longitudinal grooves formed in the casing connecting the two annular cylinders to each other, so that the pistons are guided in alternating axial movement in the fixed cylinders in rotation, if the central shaft is a rotary drive shaft.

If the engine is with spark ignition, the fuel mixture is supplied by the hollow engine shaft, by means of a cylindrical plug, integral with the cylinders and housed in the hollow shaft, so that the fuel mixture reaches all first in the chamber delimited between the two annular pistons and then enters the annular combustion chambers, between the piston heads and the bottom of the annular cylinders, when the annular pistons approach each other, in a cycle four-stroke as in a two-stroke cycle, the passage of the fuel mixture being ensured in axial channels extending over a certain axial distance in the internal face of the internal radial wall of the annular cylinders, and opening in the chambers combustion opposite a curved part of the corresponding annular piston head. The exhaust of the burnt gases is effected by exhaust orifices drilled in the external radial wall of each annular cylinder. When the pistons are pushed towards each other by the explosion of the combustible mixture in the combustion chambers, the corresponding axial fingers transmit this thrust to the corrugations of the central disc, and are thus forced to move against the inclined parts of the corrugations, which causes the rotation of the corrugated disc, and therefore of the shaft, while the spacing of the two pistons from each other results from the rotation of this corrugated disc whose inclined parts force the axial fingers to push the pistons towards the bottom of the corresponding combustion chambers, under the effect of the inertia of rotation acquired by the corrugated disc and the shaft.

In alternative embodiments, the base of each of the annular pistons has a corrugated profile, which corresponds to the corrugations of the central disc, and which comes into contact with these corrugations by means of rolling members such as balls. In this case, the projections of the undulations of a piston correspond to the recesses of the undulations of the opposite piston, in order to obtain movements of simultaneous separation or simultaneous bringing together of the two pistons.

In another variant, the pistons also have their corrugated base, but the corrugated central disc is replaced by a cross-shaped member, integral with the shaft, and carrying pairs of rollers positioned so that they come into contact with the wavy edges of the two pistons which, in this case, have perfectly corresponding corrugations, that is to say that the projections of the corrugations of one piston are opposite the projections of the corrugations of the opposite piston, so that the pistons move away from or approach each other simultaneously, as in all the other cases described in this English patent.

The ignition is ensured by candles mounted in the bottoms of the cylinders, and the number and the shape of the corrugations will depend on the type of engine and the desired speed of rotation.

Improvements to this engine have been proposed in US Patent No. 4,090,478, which describes a multicylinder and sinusoidal engine. This motor comprises a casing constituted by the assembly of two trunks of cylinders, and which has a central cylindrical bore, for the passage of a hollow shaft having, in its external lateral surface, two pairs of corrugated grooves, offset axially and at sinusoidal undulations, the central bore being surrounded by several cylindrical bores, distributed regularly in the peripheral direction around the central cylindrical bore and axes parallel to that of the latter. In each peripheral cylindrical bore are housed two independent pistons, the piston heads of which are turned towards one another so as to delimit between them a single combustion chamber per peripheral cylinder, and each of the pistons is connected by a mechanism of coupling to a pair of sinusoidal grooves, for the transformation of the reciprocating axial movement of the pistons into a rotational movement of the central hollow shaft. In this motor, the two independent pistons housed in each peripheral circular cylindrical bore are pistons which approach or move away simultaneously, and the admission of fuel mixture into the combustion chamber delimited between the two pistons, as well as the exhaust of the burnt gases of this combustion chamber are provided axially in the hollow shaft and then, radially, by a complex system of valves and valves. Likewise, ignition is ensured partially by the interior of the hollow central shaft, and at the using a complex mechanism. The coupling mechanism of each of the pistons to a pair of sinusoidal grooves of the hollow central shaft comprises two parallelepipedic pushers housed in radial passages of corresponding shape of the pistons and separated from one another radially by springs, of so that one is applied against the external lateral surface of the hollow shaft by means of balls retained in housings in a portion of a sphere hollowed out in the internal radial face of this pusher and engaged simultaneously in the sinusoidal grooves of the shaft, while the other pusher, in the external radial position, is applied against the internal radial face of the casing by means of balls, also housed in recesses in the portion of a sphere formed in the external radial face of this pusher and received moreover in longitudinal slots machined in the internal face of the casing.

As a result, such an engine has an extremely complex structure, and its manufacturing and maintenance costs are very high.

Also known from US Pat. No. 3,786,790 is an internal combustion piston engine with double action reciprocally mounted in a casing with two chambers separated from each other by a fixed annular partition. In each of the two chambers is housed an annular piston surrounding a central drive shaft which passes through the partition and, coaxially, the entire casing, and the two annular pistons are integral with one another by an annular sleeve also surrounding the central shaft and passing through the partition. The two annular pistons thus form a monolithic piston block which slides axially and alternately in one direction and in the other in the casing. A single combustion chamber is arranged in the intermediate partition separating the two chambers in which the annular pistons slide. The combustion chamber further comprises a ball valve alternately placing one of the two chambers of the casing in communication with the combustion chamber, so that the combustion and expansion time of a combustible mixture causes the displacement of a piston towards the corresponding bottom of the cylinder and simultaneously the compression by the other piston of the combustible mixture, previously admitted into the corresponding housing chamber, towards the combustion chamber in which the valve ball is moved to close the communication with the other room. Also in this engine, the transformation of the alternating axial movement of the pistons into the rotation movement of the central shaft is ensured by balls partially engaged in a spherical cap housing formed in the internal lateral surface of the connecting sleeve of the two pistons, thus than in a corrugated groove, of substantially sinusoidal shape, formed in the periphery of the central shaft.

The disadvantage of such an engine lies essentially in the extreme stresses undergone by the ball valve mounted in the single combustion chamber formed in the intermediate wall, as well as in the production of this combustion chamber and of the associated ball valve.

By the present invention, it is proposed to improve the combustion engines known by the English patent GB 11,027, without using a structure as complex and expensive as that of the engines according to US Pat. No. 4,090,478, but with reliability and higher efficiency than those of engines according to US Patent 3,486,790, which can only operate in combination with relatively complex intake and exhaust systems comprising a large number of valves.

Already known from patent applications DE-A-3226379 and DE-A-290893 are internal combustion engines substantially of the type described in GB 11027 and comprising pistons forming rigid assemblies and operating as monolithic blocks. The transformation mechanism which couples the piston block and the shaft in DE-3226379 consists of radial fingers retained in the piston block and engaged to follow the undulations around the shaft.

The internal combustion engine according to the invention, which can be a spark ignition engine, of the two or four stroke type, petrol, or even a diesel engine, operating with a feed pump, or a turbo-compressor, a carburetor or an injection pump, and which can be combined with a gearbox, a clutch, and, where appropriate, with a dynamo, a battery, etc., is an engine of the type known by the English patent GB 11.027 and comprising at least one motor shaft, driven in rotation by at least one motor assembly that the shaft crosses coaxially, and which comprises a cylindrical casing, each axial end of which is integral with one of two annular and hollow cylinders, open towards one another and each closed by a bottom on the opposite side, and two annular pistons guided in axial translation in the casing, in which they are mounted in opposition, so that each of them has a piston head engaged in sealed and reciprocating axial sliding in one respectively of the two annular cylinders, in each which an annular combustion chamber is delimited between the corresponding cylinder bottom and the piston head. Each combustion chamber is supplied by an intake system of an oxidizing gas and / or a fuel and is in communication, through the external radial wall of the corresponding annular cylinder, with an exhaust system for the burnt gases. . The two pistons, the casing, the two cylinders and the shaft are mounted coaxial around the longitudinal axis of the shaft, and the alternating axial displacements of the pistons are transformed into rotation of the shaft around its axis by a mechanism transforming movement coupling the pistons to a central part of the shaft, and comprising fingers, one end of each of which is required to follow endless undulations, peripheral around the axis of the shaft and of the same axial amplitude , which are presented by a rigid member, the two pistons being integral with one another by their base and constitute a monolithic piston block, of which a central body slides in the casing so that the two pistons move simultaneously in axial direction and alternately in one direction and in the other, and the fingers of the movement transformation mechanism being radial fingers, retained in one of the two rigid members constituted by the central part of the shaft and by the central body of the piston block, while the corrugations are defined by at least one groove formed in an axial surface of the another rigid member, and in which one or which is engaged one end of each radial finger.

The engine proposed by the invention is characterized in that the piston block comprises, at each of its axial ends, a double axial skirt comprising two annular coaxial rings around the axis of the shaft and radially spaced one of the 'other, and one of which, in the external radial position, constitutes the actual annular piston head, sliding in an annular cylinder and comprising external and internal radial segments sliding against the respectively external and internal walls of the corresponding annular cylinder, while that the annular crown in the internal radial position on the double skirt guides the piston block in its axial displacements by sliding inside the internal wall of this annular cylinder, the internal crown of each double skirt of the piston block is advantageously hollow and comprises a flat and radial ring, which is axially spaced from the central body of the piston block to which it is secured by at least one column e substantially axial and rigid, and which slides axially with sealing in an annular waiting chamber, delimited between the internal wall of the corresponding annular cylinder and a coaxial sleeve, surrounding the shaft and fixed opposite the corresponding cylinder, the flat ring of each internal ring then being pierced with axial openings regularly distributed over its surface and associated with valves, so that the internal crown forms, with the waiting chamber, a pump for admitting oxidant gas and / or fuel into the corresponding combustion chamber, and in which the valves are intended, on the one hand, to open the passage through the openings towards the inside of this internal ring, when the latter moves with the corresponding piston head towards the bottom of the corresponding cylinder, in order to admit into this hollow internal ring fuel gas and / or fuel available in the chamber d '' and, on the other hand, to close the openings of the flat ring when this internal ring moves with the corresponding piston head towards the other cylinder, in order to push oxidant gas and / or fuel into the corresponding combustion chamber, through holes drilled in the internal wall of the corresponding cylinder, preferably near the bottom dead center of the corresponding annular piston.

According to alternative embodiments of the motor according to the invention, the motor shaft can pass through a single motor assembly and be actuated by it, or else the motor shaft can pass through several motor assemblies and be actuated by one or more of those -ci, which allows to leave one or more engine assemblies at rest.

In addition, in each engine assembly, the spacing of the annular cylinders is of course determined by the axial length of the common casing which separates them, so that when an annular piston is at its top dead center (TDC), the another annular piston is at its bottom dead center (PMB) in the other annular cylinder.

Finally, when the forces transmitted between the pistons and the central shaft require their distribution simultaneously over several grooves wavy, the corrugations of these grooves are necessarily in phase.

In an advantageously simple and reliable embodiment of the movement transformation mechanism, the central part of the shaft is a swollen cylindrical part, of larger diameter than the adjacent axial parts of the shaft which are housed in the motor assembly , and in the cylindrical lateral surface of which is formed each corrugated groove in which the internal radial ends of the fingers move crossing radially the central body presented by the piston block and which is tubular and slides axially around the swollen central part of the shaft, each groove in this central part forming regular undulations, the number of which depends on the desired speed of rotation for the shaft.

Advantageously, to ensure good peripheral distribution of the forces, simultaneously on the various undulations of a groove in the shaft, as well as undulations of a groove on the undulations of the other groove or grooves, the central body of the According to the invention, the annular piston block is traversed in its middle part by radial finger guide holes, these holes being grouped into at least two identical sets of at least two holes each, the different sets of holes being equidistant from each other. from each other in circumferential direction around the axis of the shaft, and the holes of each assembly being parallel to each other and offset axially in the same radial plane, while the central swollen part of the shaft has grooves wavy in phase, in number equal to the number of holes per set of holes, and offset axially in correspondence with the axial offsets of the holes of each set of holes.

Advantageously moreover, the radial fingers of the movement transformation device are simultaneously used to ensure the axial guidance of the piston block in the assembly formed by the casing and the two annular cylinders. To this end, according to the invention, the casing has axial openings, opening into its cylindrical bore, and each placed radially opposite a set of holes in the piston block, the radial fingers housed in the holes this assembly each having its external radial end engaged in the corresponding lumen, which thus guides them axially with the piston block in the casing.

In order to guarantee good cooperation of the radial fingers with the corresponding grooves of the shaft, the internal radial end of each of the fingers passing through the same set of holes drilled in the piston block is kept engaged in a corrugated groove in the central part. of the shaft by a cage, fixed on the external face of the casing around the corresponding lumen, and united with bearings ensuring good circulation of the external radial ends of these fingers in said corresponding lumen. In addition, the part of each finger which passes through the piston block is advantageously mounted in the corresponding hole formed in the piston block by means of at least one needle bearing.

In addition, it is advantageous for each radial finger guided in a radial hole and in a lumen which respectively pass through the piston block and the casing, to be divided, substantially at mid-length, into two parts arranged end to end and such that the internal radial end of the internal radial part of the finger and the external radial end of the external radial part of the finger are engaged and can rotate independently of each other, and possibly in opposite directions, respectively in the corresponding groove of the shaft and in the corresponding light of the casing.

In the best embodiment known to date, the swollen central part of the shaft has two wavy grooves, and the central body of the piston block is pierced with four sets of two radial holes each, to accommodate eight fingers guided axially in four longitudinal housing light and which are closed to the outside by four cages.

In order to complete this best embodiment, in which each double end skirt of the piston block simultaneously constitutes the actual piston head and a pump for admitting oxidant gas and / or fuel in the corresponding combustion chamber, it is advantageous that, in addition, a circular flange, coaxial with the casing, the piston block, and the cylinders, is fixed against the bottom of each annular cylinder and has a central opening provided with a passage and rotation guide bearing of the motor shaft.

It is therefore advantageous for the combustion gas and / or fuel intake system to have an intake manifold extending parallel to and outside the casing, ending at each of the two axial ends of the assembly. motor by a substantially radial duct which is connected to an annular tube provided with axial openings arranged facing axial orifices formed in the flange on the corresponding side, and in which independent and compensated valves are mounted, allowing the supply of the corresponding waiting chamber for oxidizing gas and / or fuel.

In order to promote the cooperation of the supply valves mounted in the axial orifices of the end flanges of the engine assembly and of the valves associated with the axial openings formed in the flat ring of the internal crown in the configuration of the intake pump and so that the phase of compression of the volume of oxidant gas and / or of fuel contained in the internal ring, for its transfer into the intake chamber, is simultaneous with an intake phase by aspiration of a new volume of oxidant gas and / or fuel in the waiting chamber, it is advantageous that the longitudinal axis of each intake valve is coincident with the longitudinal axis of one of the openings drilled in the flat ring of the internal crown which slides in the corresponding waiting chamber.

Finally, when the engine according to the invention is of the spark-ignition type, the flanges and the bottoms of the cylinders are advantageously pierced with opposite axial passages, opening out into a corresponding combustion chamber, and in which are mounted ignition flues. .

Of course, in such an embodiment, the relative axial dimensions of the outer ring and the inner ring of each double skirt are chosen so that the annular pump thus associated with each piston head ensures good supply of the corresponding annular combustion chamber , by stirring at constant displacement of the quantity of combustible mixture necessary to obtain the best yield.

• La figure 1 représente, en perspective, un ensemble superposé comportant deux cylindres annulaires et deux flasques d'extrémité, pour coopérer avec une paire de pistons;
• La figure 2 représente, en perspective, deux pistons annulaires assemblés par leur base et formant un bloc-piston monolitique;
• La figure 3 représente, en perspective, un carter cylindrique destiné à être solidarisé à l'ensemble des deux cylindres et des deux flasques de la figure 1, et dans lequel le bloc piston de la figure 2 est destiné à être monté coulissant;
• La figure 4 représente, en perspective, un arbre moteur qui est logé dans l'ensemble moteur constitué par le bloc piston,les deux cylindres, les deux flasques et le carter,
• La figure 5 représente, schématiquement, en coupe longitudinale et axiale, les pièces essentielles d'un ensemble moteur monté coaxialement autour de l'axe longitudinal de l'arbre moteur central, et
• La figure 6 représente, schématiquement, en demi-coupe transversale, des doigts radiaux d'un mécanisme de transformation du mouvement axial et alternatif du bloc piston en un mouvement de rotation de l'arbre, et le guidage axial du bloc piston dans le carter, pour éviter sa rotation par réaction.

The invention will be better understood and other advantages and characteristics of the invention will emerge from the description given below, without limitation, of a preferred embodiment of the engine according to the invention, described with reference to the drawings annexed on which:

• Figure 1 shows, in perspective, a superimposed assembly comprising two annular cylinders and two end flanges, for cooperating with a pair of pistons;
• FIG. 2 represents, in perspective, two annular pistons assembled by their base and forming a monolithic piston block;
• 3 shows, in perspective, a cylindrical casing intended to be secured to the assembly of the two cylinders and the two flanges of FIG. 1, and in which the piston block of FIG. 2 is intended to be mounted sliding;
• FIG. 4 represents, in perspective, a drive shaft which is housed in the engine assembly constituted by the piston block, the two cylinders, the two flanges and the casing,
• FIG. 5 schematically represents, in longitudinal and axial section, the essential parts of an engine assembly mounted coaxially around the longitudinal axis of the central drive shaft, and
• FIG. 6 schematically represents, in half cross-section, radial fingers of a mechanism for transforming the axial and reciprocating movement of the piston block into a rotary movement of the shaft, and the axial guidance of the piston block in the casing , to avoid its rotation by reaction.

Figures 1 to 6 show an internal combustion engine, of the spark-ignition type and whose combustion cycle is two-stroke, to simplify the description below. This engine essentially comprises a piston block 1, consisting of two annular pistons 2 and 3 assembled in opposition by their base, of circular cross section, so that these assembled bases constitute a central body 1 a cylindrical and tubular by which the piston block 1 slide axially in the internal bore of a cylindrical casing 4, of circular section, each of the axial ends of which has a radial fixing flange. This casing 4 is, at each of its two axial ends, secured to an open axial end of an annular cylinder 5, in the form of a hollow crown. These annular cylinders 5 are each closed at its axial end opposite to that by which it is secured to the casing, by a bottom 5 a against which is applied one of two circular flanges 6, each having a central opening 7 provided with a bearing 17 to allow the maintenance, the axial passage and the guiding in rotation of a motor shaft 8 or motor output shaft, which crosses coaxially, around its longitudinal axis AA, the casing 4, the two cylinders 5 on the one hand and on the other side of this casing 4, and the two end flanges 6 on either side of the cylinders 5, as well as the piston block 1 formed of the pistons 2 and 3 assembled. The parts of the motor assembly thus formed around the shaft 8 are kept stacked and tightened axially by a series of axial studs (not shown) which connect the two flanges 6. As shown in FIG. 2, the monolithic piston block 1 , formed by the assembly in opposition of the annular pistons 2 and 3, has a cylindrical and tubular central body 1 a which is pierced, in its middle part, with eight radial guide holes 18, grouped in four pairs of holes which are regularly distributed in circumferential direction around the longitudinal axis of the tubular piston block 1, that is to say which are positioned at 90 ° from each other, the two holes 18 of each pair being further axially spaced one of 1 other, parallel to each other in the same radial plane of the piston block 1. Thus, these eight holes open into the outer side surface of the tubular central body 1 has in its inner side surface, and are pairwise in vis-à-vis each other. At the opposite axial side end to the central body 1a of the piston block 1, each annular piston 2 and 3 comprises a double axial skirt 2 a, 3 a, consisting of two coaxial annular rings, one of which, in an external radial position , is an outer or peripheral ring 9 which is radially spaced from the other, in the internal radial position or internal ring. This internal ring essentially consists of a flat ring 10 disposed radially and coaxially, and secured to the corresponding side of the central body 1 a of the piston block 1 by a plurality of axial columns 10 a , and the flat ring 10 is pierced with 11 has axial holes, regularly distributed over its surface in the circumferential direction, and with which are associated valves 11. These valves 11 are leaf-spring valves which are fixed on the face of the flat ring 10 which faces the body central 1 a of the piston block, and which are prestressed in the closed position of the orifices 11 has drilled in the flat ring 10 of the internal crown, so that the latter can act as an intake pump, ensuring the supply of a cylinder 5 in a combustible mixture, as explained below.

The outer ring 9 of the double axial skirt 2 a or 3 a of the piston 2 or 3 is shaped as the actual piston head, which is engaged so as to slide axially with sealing in both directions in one of the cylinders annular and hollow 5 (see FIGS. 2 and 5), in which an annular combustion chamber 12 is delimited between the corresponding bottom 5 a of the cylinder 5 and this external radial crown 9. The internal radial wall 13 of each cylinder 5 is pierced with intake holes 14, which open into the corresponding combustion chamber 12, when the external radial crown 9 or piston head proper is practically in its bottom dead center position (PMB), that is to say when it is moved axially as far as possible from the bottom 5 a of the corresponding cylinder 5. Substantially at the same axial level, the external radial wall 15 of each annular cylinder 5 is pierced with holes 16 which open to the outside of the corresponding cylinder 5 to allow the escape of combustion gases. These holes 14 and 16, which are substantially radial, and respectively delimiting the intake passages and the exhaust passages to or from each annular combustion chamber 12, are distributed regularly or grouped into sets of holes distributed regularly over the entire periphery of the corresponding cylinder 5, as shown in FIG. 1. In this figure it can be seen that the exhaust holes 16 are grouped in sets of three holes arranged side by side in circumferential direction, these sets of three holes being themselves regularly distributed in this same circumferential direction.

As is clearly shown in Figures 1 and 5, the two annular cylinders 5 are mounted in opposition, on either side of the housing 4, and being open one towards the other, in such a way that the external radial crown 9 of the double axial skirt 2 a or 3 a of each piston 2 or 3 can move axially in the combustion chamber 12 of the corresponding cylinder 5, the two cylinders 5 being separated from each other with a spacing which corresponds to the axial length of the casing 4.

As shown in FIGS. 4 and 5, the shaft 8 has, at mid-length, a central part 19 which is swollen, of cylindrical shape of circular section, with a larger diameter than the adjacent axial parts of the shaft 8 In the external lateral face of this central part 19 are formed two grooves 20, of square cross section, which are sinusoidal and peripheral grooves, closing on themselves, or even continuous and endless grooves, and these grooves 20 each form four regular undulations in the longitudinal direction of the shaft 8, and on its periphery, that is to say undulations of the same axial amplitude.

As shown in FIGS. 3 and 5, the housing 4 has four slots 21 drilled radially and extending in the longitudinal direction so as to open into the internal cylindrical bore of the housing 4. These slots 21 are regularly distributed in the circumferential direction around the longitudinal axis of the casing 4, so that they are separated from each other by an angle of 90 °, in order to coincide each with one of the four pairs of guide holes 18 formed radially in the central body 1 a tubular of the piston block 1 shown in Figure 2.

As shown in FIGS. 5 and 6, eight radial fingers 22, arranged in four pairs of two fingers, are each introduced radially into a lumen 21 of the casing 4 and into one of the two corresponding radial holes 18 passing through the central body 1 a . Each of the fingers 22 is thus housed radially through the casing 4 and the piston block 1, so that its internal radial end is housed respectively in one of the two grooves 20 wavy in phase and offset axially along the shaft 8 with the same spacing as that which separates the two radial holes 18 from a pair of holes centered in the same radial plane of the central body 1 a .

Each of the four pairs of radial fingers 22 is held so that the internal radial end of each of the two corresponding fingers 22 is engaged in that of the two grooves 20 which occupies the corresponding axial position on the central part 19 of the shaft 8, by means of one of four identical cages 23, fixed on the outer part of the casing 4, and each around one of the four slots 21, and each cage 23 contains two ball bearings (not shown) in order to improve the displacement, in the corresponding lumen 21 of the casing 4, of the external radial ends of the two fingers 22 projecting in this lumen 21.

As shown in FIGS. 5 and 6, each of the fingers 22 is divided, substantially at mid-length, into two parts 22 a and 22 b , which allows the internal radial end of the internal radial part 22 a to roll in the corresponding groove 20 of the shaft 8, and at the external radial end of the corresponding external radial part 22 b , to rotate and roll in the cage 23 and in the slot 21 independently of one another, and in particular in the opposite direction.

As shown in FIGS. 1 and 5, each flange 6 and each cylinder 5 have an annular shape and delimit a central opening for the passage of the drive shaft 8, and eight holes 24, equidistant in circumferential direction, are drilled in coincidence and in the axial direction through the flange 6 and the bottom 5 a of the adjacent cylinder, so as to open into the annular combustion chamber 12, to receive spark plugs which will be activated by a common or individual ignition device, not shown .

As shown in FIG. 5, the fuel mixture is supplied to the engine assembly by a supply system comprising a supply or intake manifold 25, which extends parallel to the shaft 8 but outside the casing 4, and which itself receives the fuel mixture coming from a carburetor (not shown) by a radial inlet opening 26. This inlet manifold 25, longitudinal, has its two ends connected perpendicularly by substantially radial conduits 25 a to two annular end tubes 27 which are applied coaxially against the external axial faces of the two flanges 6. To allow the passage of the combustible mixture, each of the two annular tubes 27 is open on the side of the flange 6 corresponding, opposite orifices axial longitudinal 28 formed through the corresponding flange 6, and regularly distributed in circumferential direction, radially inside the spark plug holes 24. These axial orifices 28 of the flanges 6, whose axes are coincident with those of at least some of the passages axial 11a of the neighboring flat ring 10, serve for the axial guidance of valves 29, independent and compensated by springs (not shown), each of which is housed by its rod in an orifice 28, so that the valve head is of the side of the internal axial face of the corresponding flange 6. Each valve 29 can thus be moved axially towards the central body 1a of the piston block 1, so that the valve head is spaced from the corresponding seat machined in the inner axial face of the flange 6 corresponding to let in the combustible mixture in a waiting chamber 30 which is an annular chamber delimited radially between the internal radial wall 13 of the corresponding annular cylinder 5 and an axial sleeve 35, supported coaxially around the shaft 8 by the corresponding flange 6, and extending axially substantially up to the bulged part 19 of the shaft 8, and so that the central body 1 has the piston block 1 slides with sealing around this sleeve 35. In addition, the internal crown of the corresponding double axial skirt, and which is formed by the flat ring 10 and its columns 10 a connecting to the central body 1 a , is also slidably mounted axially in this waiting chamber 30, which is subdivided into two x parts, including an upstream part 30 a , adjacent to the flange 6 and the corresponding valves 29, and of which the other part is a downstream part 30 b , adjacent to the central body 1 a . These two parts 30 a and 30 b are separated from each other by the flat ring 10, which slides with sealing on the one hand against the internal radial wall 13 of the corresponding annular cylinder 5 and on the other hand against the sleeve 35 delimiting this chamber 30.

Thus, the internal crown, formed of the flat ring 10 with its axial passages 11 a and its valves 11, is secured by the columns 10 a to the central body 1 a , and forms with the waiting chamber 30 a pump admission of fuel mixture into the corresponding annular combustion chamber 12, operating as follows: at start-up, during the first axial strokes of the piston block 1 in the casing 4 and the two cylinders 5, the filling of the combustion chambers 12 is imperfect, but a balance is established very quickly, and the filling becomes normal. During the admission time, for piston 2 for example, this piston 2 moves towards its bottom dead center (PMB), that is to say it moves away from the bottom 5 a of the cylinder 5 in which slide the corresponding 9 piston head, which causes the admission of the combustible mixture in the upstream part 30a of the holding chamber 30. this is ensured by the recoil of the internal ring and the flat ring 10 which, on the one hand, due to the increase in the volume of part 30 a of the waiting chamber 30, controls by suction the opening of the corresponding valves 29 and the arrival in part 30 a of the chamber 30 d '' a fresh volume of combustible mixture coming from the intake manifold 25, while, on the other hand, as the valves 11 remain closed shutter openings 11 position has the flat ring 10 simultaneously causes compression of the fuel mixture volume in the downstream portion 30 b of the waiting room 30, which results in the transfer of this volume of combustible mixture into the corresponding annular combustion chamber 12 through the intake orifices 14. This introduction of combustible mixture into this combustion chamber 12 drives out the gases previously burned in this chamber through the holes d 'exhaust 16 leading to peripheral tubes 31 connected to an exhaust manifold 32. During the compression time of the piston 2, that is to say when the piston head 9 moves in the corresponding cylinder 5 towards the bottom 5 a of the latter, that is to say towards its top dead center (PMB), the corresponding inner ring and its flat ring 10 undergo the same axial translation, which has for effect of compressing the upstream part 30 a of the chamber 30, while the downstream part 30 b is dilated. This causes on the one hand the closing of the corresponding valves 29, applied against their respective seats on the flange 6 by cutting off any arrival of combustible gas coming from the intake manifold 25, and, simultaneously, the valves 11 open by bending of the spring blades which constitute them towards the interior of the chamber part 30 b , due to the compression of the combustible mixture in the chamber part 30 a , so that combustible mixture is transferred from this upstream chamber part 30 a to the downstream part 30 b . In this way, the intake pump constituted by the cooperation of the flat ring 10 of the inner ring of the double axial skirt of each piston 2 or 3, with the corresponding waiting chamber 30, operates as a fuel mixture suction pump in the upstream part 30 a this chamber and discharge of the combustible mixture of the downstream portion 30 b of the chamber inwardly of the corresponding 12 annular combustion chamber, after transfer of the upstream portion 30a to the downstream portion 30b.

Of course, due to the fact that the pistons 2 and 3 form a monolithic piston block 1, the retraction of an annular piston 2 or 3 towards its PMB, corresponds to the compression of a fresh volume of combustible mixture by the annular piston 3 or 2 opposite which advances simultaneously towards its TDC

When an annular piston 2 or 3 arrives at its TDC, the corresponding spark plugs cause the ignition of the fuel mixture contained in the corresponding annular combustion chamber 12, and the explosion drives this piston towards its PMB, by moving the opposite piston towards its TDC, causing a new cycle.

The intake pumps thus produced are therefore subjected to the same alternating axial movements as the pistons, which are the driving elements for the pumps and drive them, but which can only deliver their driving force because of the supply of fuel mixture provided by these pumps.

Each outer ring 9, forming the actual piston head, of the corresponding piston 2 or 3, has internal and external segments 34 which allow good sealing against the inner and opposite cylindrical faces of the outer 15 and inner 13 radial walls defining the annular combustion chamber 12.

The four pairs of radial fingers 22 transform the translational movement of the piston block 1 into a rotary movement of the motor shaft 8, by the fact that any axial movement of the piston block 1 causes the fingers 22 in a translational movement of the same amplitude, and these fingers 22 roll by their internal radial end in the corrugated grooves 20 of the shaft 8, causing a rotary movement of the latter.

In FIG. 2, the axial spacing of the two holes 18 of a pair of holes in a particular angular position at the periphery of the central body 1 a , corresponds to the spacing of the two corrugated grooves 20 of the central part 19 of the 'shaft 8 shown in Figure 4, and the height or amplitude of a ripple is substantially equal to the axial stroke of the piston 1. In addition, the radial fingers 22 can rotate on themselves in the holes 18 of the block piston 1 by means of needle bearings 33 mounted in each of these holes 18, as shown in FIGS. 5 and 6.

In a variant of the motor according to the invention, the movement transformation mechanism is reversed, insofar as radial fingers are housed and retained in the bulged central part 19 of the motor shaft 8, so that one at less of their ends, in the external radial position, is engaged and can roll in one of the sinusoidal grooves formed in the cylindrical face in the internal radial position on the annular piston block 1, and in particular on its central body 1 a .

In such an engine, it will also be noted that each of the flanges 6 is necessary to ensure the admission of oxidant gas and / or fuel to the annular combustion chambers 12, as well as for the mounting and guiding of the rotary shaft. 8. On the other hand, these flanges 6 are only pierced with spark plug receiving holes if the engine is of the spark-ignition type. If this engine is a diesel engine, there is no need to drill the flanges 6 and the bottoms 5 has cylinders 5 for the spark plug housing.

The internal combustion engine according to the invention finds more particularly its application for the equipment of airplanes and other types of aerodynes, because of the facility which it presents to adapt the rotation speed of the shaft. to the nature of the use, but, of course, such an engine can be used to equip marine or land vehicles.

The reference signs inserted after the technical characteristics mentioned in the claims are intended only to facilitate understanding of the latter, and in no way limit their scope.

Claims (11)

1. Internal-combustion engine, comprising at least one driving shaft (8), driven in rotation by at least one engine assembly which the shaft penetrates coaxially (AA) (8), and which comprises a cylindrical housing (4) each axial end of which is integral with one of two hollow and annular cylinders (5), open towards each other and each closed by a base (5a) on the opposite side, and two annular pistons (2, 3) guided in axial translation in the housing (4) in which they are fitted opposed, so that each of them exhibits a piston head (9) engaged to slide fluid-tightly in axial reciprocation each in one of the two annular cylinders (5), in each of which an annular combustion chamber (12) is delimited between the corresponding cylinder base (5a) and the piston head (9), each combustion chamber (12) being supplied by an admission system (10, 30, 29, 28, 25) for a conburent gas and/or a fuel and being in communication, through an exterior radial wall (15) of the corresponding annular cylinder (5), with a combustion gas exhaust system (16, 31, 32), the two pistons (2, 3), the housing (4), the two cylinders (5) and the shaft (8) being fitted coaxially about the longitudinal axis (AA) of the shaft (8) and the reciprocating axial movements of the pistons (2, 3) being converted into rotation of the shaft (8) about its axis (A) by a movement oonversion mechanism coupling the pistons (2, 3) to a central part (19) of the shaft (8), and comprising pawls (22), one end of each of which is compelled to follow endless undulations, circumferential (20) about the axis (AA) and of the same axial amplitude, which are exhibited by a rigid member, wherein the two pistons (2, 3) move simultaneously in the axial direction and alternately in each sense, and in that the pawls (22) of the movement conversion mechanism are radial pawls, retained in one of the two rigid members formed by the central part (19) of the shaft (8) and by the central element (1a) of the piston block (1), whereas the undulations (20) are defined by at least one groove made in an axial surface of the other rigid member, and in which or in each of which, one end of each radial pawl (22) is engaged, characterized in that the piston block (1) comprises, at each of its axial ends, an axial double skirt (2a, 3a) comprising two annular crowns (9, 10) coaxial about the axis (AA) of the shaft (8) and mutually spaced radially, and one of which (9), in the outer radial position, forms said head of the corresponding annular piston (2, 3), sliding in the corresponding annular cylinder (5) and comprising outer and inner radial serpents (34), sliding against the outer (15) and inner (13) walls respectively of said annular cylinder (5), whereas the annular crown in the inner radial position (10) on the double skirt guides the piston block (1) in its axial movements by sliding within the inner wall (13) of said annular cylinder, the inner annular crown (10) of each double skirt of the piston (1) is hollow and comprises a flat and radial ring (10) which is spaced axially from the central element (1a) of the piston block (1) to which it is attached by at least one substantially axial and rigid column (10a) and which slides axially fluid tightly in an annular ante-chamber (30) delimited between the inner wall (13) of the corresponding annular cylinder (5) and a coaxial sleeve (35), surrounding the shaft (8) and fixed relative to said cylinder (5), the flat ring (10) of each inner crown in provided with axial apertures (11a) distributed regularly over its surface and associated with valves (11), so that the inner crown, with the antechamber (30), forms an admission pump for comburent gas and/or fuel into the corresponding combustion chamber (12), and in which the valves (11) are intended, on the one hand, to open the passage through the apertures (11a) into the interior of this inner crown, when the latter moves with the head (9) of the corresponding piston (2, 3) towards the base (5a) of the corresponding cylinder (5), to admit into this hollow inner crown (10) comburent gas and/or fuel available in the antechamber (30), and, on the other land, to close the apertures (11a) when this inner-crown (10) moves with the corresponding piston head (9) towards the other cylinder (5), in order to deliver comburent gas and/or fuel into said combustion chamber (12) through orifices (14) provided in the inner wall (13) of the corresponding cylinder (5).

2. An engine as claimed in claim 1, characterized in that said central part (19) of the shaft (8) is an enlarged cylindrical part, of greater diameter than the adjacent axial parts of the shaft which are housed in the engine assembly, and in the lateral cylindrical surface of which each undulated groove (20) is made, in which move the inner radial ends of the pawls (22) radially penetrating said central element (1a), which is tubular and slides axially about said central part (19) of the shaft (8), each groove (20) forming regular undulations, the number of which is a function of the required speed of rotation of the shaft (8).

3. An engine as claimed in claim 2, characterized in that the central element (1a) of the annular piston block (1) is penetrated in its median part by radial guide holes (18) for the pawls (22), said holes (18) being grouped in at least two identical sets of at least two holes (18) each, the different sets of holes (18) being mutually equidistant in the circumferential direction, and the holes of each set being mutually parallel and staggered axially in one and the same radial plane, whereas the enlarged central part (19) of the shaft (8) exhibits undulated grooves (20) in equal phase and number to the number of holes (18) per set of holes, and axially staggered correspondingly to the axial staggering of the holes (18) of each set of holes.

4. An engine as claimed in claim 3, characterized in that the housing (4) exhibits axial ports, (21) leading into its cylindrical bore, and each placed radially opposite a set of holes (18) of the piston block (1), the pawls (22) housed in the holes (18) of said set each having its exterior radial end engaged in the corresponding port (21), which guides them axially with the piston block (1) in the housing (4).

5. An engine as claimed in claim 4, characterized in that the inner radial end of each of the pawls (22) penetrating one and the same set of holes (18) in the piston block (1) is kept engaged in an undulated groove (20) of the central part (19) of the shaft (8) by a cage, (23) fixed on the exterior face of the housing (4), about the corresponding port (21), and equipped with bearings ensuring good circulation of the outer radial ends of said pawls (22) in said corresponding port (21).

6. An engine as claimed in claim 5, characterized in that each radial pawl (22) guided in a radial hole (18) and in a port (21) which penetrates the piston block (1) and the housing (4) respectively, is divided, substantially at mid-length, into two parts (22a, 22b) arranged end ot end and such that the inner radial end of the inner radial part (22a) and the outer radial end of the outer radial part (22b) are engaged and can rotate mutually independently, and optionally in opposite senses, in the corresponding groove (20) of the shaft (8) and of the corresponding port (21) of the housing (4) respectively.

7. An engine as claimed in either of claims 5 and 6, characterized in that the enlarged central part (19) of the shaft (8) exhibits two undulated grooves (20), and the central element (1a) of the piston block (1) is provided with four sets of two radial holes (18) housing eight pawls (22) guided axially in four ports (21) of the housing (4) which are closed towards the outside by four cages (23).

8. An engine as claimed in any of claims 1 to 7, characterized in that a circular plate (6), coaxial with the housing (4), with the piston block (1) and with the cylinders (5), is fixed against the base (5a) of each cylinder (5) and exhibits a central aperture (7) fitted with a passage and rotational guide bearing for the shaft (8).

9. An engine as claimed in claim 8, characterized in that the admission system for comburent gas and/or fuel comprises an admission pipe (25), extending parallel to the housing (4) and outside the latter, terminating at each of the two axial ends of the engine assembly into a substantially radial conduit (25a) which is connected to an annular tube (27) provided with axial apertures opposite axial orifices (28) made in the plate (6) on the corresponding side, in which independent and compensated valves (29) to supply said antechamber (30) with comburent gas and/or fuel are fitted.

10. An engine as claimed in claim 9, characterized in that the longitudinal axis of each admission valve (29) coincides with the longitudinal axis of one of the apertures (11a) made in the flat ring (10) of the inner crown sliding in the corresponding antechamber (30).

11. An engine as claimed in any of claims 8 to 11, of the controlled ignition type, characterized in that the plates (6) and the bases (5a) of the cylinders (5) are provided with opposite axial passages (24), leading into the annular combustion chambers (12) and in which sparking plugs are fitted.

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