Abstract:
The engine includes at least two cylinders  2  laid out flat and opposed one to the other, a crankshaft  9  to transmit to the output shaft of the engine the energy provided by the explosions in cylinders  2 . A rigid connecting rod assembly  18  connects crankshaft  9  to the pistons  17  mobiles in cylinders  2 . Connecting rod assembly  18  is assembled directly on the crankshaft  9  which is cast solid, without sliding shoe. The bottom of each cylinder  2  ends in a trunked cone whose top determines, with an end of piston  17 , an exhaust port which is closed before the lights of transfer, by starting a strong depression and a overfeeding of the engine.

Description:
FIELD OF THE INVENTION 
     The present invention relates to an spark-ignition engine of the type flat and with opposite cylinders. 
     BACKGROUND OF THE INVENTION 
     One flat knows engines and with opposed cylinders, which are equipped with an reticulated connecting rod assembly placed in a casing in two parts whose mating plane is located in the axis of the crankshaft and perpendicular to the plan which passes by the axis of the cylinders. 
     With this known design of the engines flat and with opposed cylinders, the pressures of explosion are transmitted, through the crankshaft, directly with the screw fasteners of the two half-casings. So very quickly, the casing becomes deformed and flees. 
     Moreover, with the known engine mentioned above, the crankshaft is heavier because it must comprise masses of balancing much more important. The engine itself is heavy, bulky, and with much of parts moving. 
     SUMMARY OF THE INVENTION 
     The present invention has as an aim to cure the disadvantages mentioned above presented by the engines known flat and opposite cylinders mentioned above, and it proposes for this purpose to produce an spark-ignition engine, flat and with opposed cylinders, which constitutes a more compact unit, more rigid and with a maximum of standard and modular parts. It aims at constructing a lighter, more reliable unit and of a less cost price, comprising less parts moving, and showing of a reduced rate of consumption and of pollution. 
     The spark-ignition engine according to the invention is of the type including at least two cylinders laid out flat and opposed one to the other, a crankshaft ensuring the drive the shaft of exit of the engine of the energy provided by the explosions in the known as cylinders, and a connecting rod assembly connecting the crankshaft to the mobile pistons in the known as cylinders. It is characterized in that the known as connecting rod assembly is rigid and is assembled directly on a cast solid crankshaft, without sliding shoe. 
     Indeed, by replacing the conventional connecting rod assembly articulated by a rigid connecting rod assembly, the system balances itself and the inertias are withdrawn instead of being cancelled to no purpose, by ensuring a profit of power of approximately 30%. The masses of balancing of the crankshaft are used only for balancing of the crank pins, and, so they are much lighter than with an articulated connecting rod assembly for which it is necessary to take account of the mass of the rod and the piston. 
     With a rigid connecting rod assembly according to the present invention, the pistons which are perfectly guided do not touch the cylinders, only the ring seals ensure the contact and the sealing with a very weak surface of friction. 
     According to an additional characteristic of the invention, the spark-ignition engine includes two identical half-casings whose mating plane passes by the axis of the cylinders, the rigid connecting rod assemblies, the flanged guides of the rigid connecting rod assemblies, the pistons and the cylinder heads of the engine. With this provision, the assembly is facilitated and, once the assembled casing, it occurs only very few efforts on the bolts assembling the two half-casings. The casing thus obtained has same rigidity as a cast solid casing. 
     According to another characteristic of the invention, the half-casings are positioned one compared to the other by the components of the engine, this positioning being ensured in a plan by sealing rings and bearings of guidance of the crankshaft and, in a perpendicular plan, by the flanged guides of the rigid connecting rod assembly. One thus obtains a perfect positioning of the half-casings one compared to the other, without use of the centerpiece necessary with a conventional casing and which bring often only one defective precision. 
     According to still another characteristic of the invention, the bottom of each cylinder ends in a truncated cone whose top determines an annular light of exhaust with the end of the piston emerging inside the cylinder. This passage of exhaust entirely free, and with a precise adjustment of the exhaust fumes passage by the length of the small diameter of the piston, constitutes a particularly advantageous solution 
     This solution is made possible, according to a complementary characteristic of the invention, by the fact that the piston presents contrary to the connecting rod assembly a part of small diameter on which the sealing is held by the interior diameter of a ring placed between the cylinder and the cylinder head of the engine, the end of the piston emerging from the known as ring at each point died low, by then allowing the passage of exhaust fumes by the interior diameter of the known as ring. 
     The lubrication of the ring and the cooling of the cylinder are ensured by an oil circulation in an annular throat laid out between the ring and a shim external to the ring. The gauged exhaust of the oil of the annular throat regulates the oil pressure of the engine. 
     So that the exhaust fumes are evacuated easily, the cylinder presents a conical end which ensures their guidance and their concentration. 
     The conical part of the cylinder allows a dynamic overfeeding of the engine. Indeed, during closing to the exhaust of the cone of pressure determined by the cone at the head of the cylinder and the small diameter of the piston, the speed of exhaust of gases is close from the speed of the sound and, with speed, these gases are crushed in the cone and are very strongly densifient from the top of the cone where the pressure is strongest (about 100 bars) to reach a null pressure at the place of the largeest diameter of the cone, the remainder of the cylinder being with a negative pressure whose absolute value increases while approaching the lights of transfer. 
     Because of the important depression on the level of the lights of transfer, the induction valves open instantaneously under the effect of the difference in pressure between the atmospheric pressure outside the cylinder and the vacuum inside the cylinder, by starting a complementary filling of air. When the induction valves are closed during the closing of the lights of transfer, gas pressure which was standardized a little inside the cylinder reached 4 bars or more before compression does start. This value of 4 bars is however only indicative, and it varies according to the pressure losses, of the dimensions given to the exhaust ports, of transfer, and admission, and speed of revolutions of the engine. 
     The point angle of the conical part of the cylinder also has a great influence on the value of the dynamic pressure, the aforementioned increasing when this angle increases up to a value of approximately 60°. Thus, more dynamic pressure will be sought, and more one will decrease the point angle of the conical part of the cylinder, until a limit imposed by the pressure loss on the exhaust which becomes too important and/or by a too great height of the unfavourable cone on a good general design of the head of the cylinder. 
     The dynamic pressure thus generated is so important that the volumetric filling, carried out by the lower part of the pistons in ascending phase, has little importance and can even be lower than 1 without influencing in a sensitive way the dynamic pressure of overfeeding obtained at the moment of the closing of the lights of transfer, right before the phase of compression. It is thus possible to use stems of connecting rod assembly of diameter higher than the small diameter of the pistons, which finds mainly its application on the small engines and the micro engines. 
     According to another characteristic of the invention, the pistons can be out of steel, aluminium or another metal, and the part of small diameter of each piston is hollow, is filled by a coolant and is closed by a tight stopper. One obtains thus that the combustion chamber remains hot, with a uniform temperature on the height of the piston. According to another realization, the pistons can be out of aluminium with, on the surface, an insulating ceramic layer of great hardness, which is self-lubricating hot like cold. The temperature is then standardized by conduction on all the matter of the piston, which presents the thickest possible walls for a good conduction of the calories of the end of the small diameter of the piston until worms the ring and the shim of the large diameter of the aforementioned. 
     The end of the part of small diameter of the piston is then free, and not plugged up anymore, and it presents only one hole for the passage of the head of screw. The end of the external diameter of the piston ends in a light round cone and is polished to facilitate the introduction of the piston into the ring of exhaust. 
     According to another characteristic of the invention, it is the latch-tightening screw of the three parts of the piston on the rigid connecting rod assembly which is used to center the parts compared to the axis of the stems of the rigid connecting rod assembly so that the pistons are centered perfectly on the stems of the rigid connecting rod assembly. 
     According to another characteristic of this invention, the components of the engine are manufactured separately, which facilitates manufacture and makes it possible to use materials and surface treatments adapted to each function. These components which pile up, are centered and blocked between them include the stage of connecting rod assembly, the eduction valve box, the sleeve, the cylinder, the ring with its shim and the cylinder head, and they are sandwiched between the cylinder head and the casing. 
     According to another characteristic of the invention, the crankshaft internally comprises conduits of lubrication of large diameter going from the outside of a crank pin of the crankshaft thru the middle of a stage of the crankshaft, two known as conduits coming from two crank pins of the crankshaft thus which can be connected inside a crankshaft bearing while being fed by a single oil arrival under pressure. Of this way, all the crank pins and the stages of the crankshaft can be reduced, even in the case of a crankshaft with four crank pins. Each crank pin has jets for the passage of oil on the plane faces of an attachment, or a hole of lubrication. 
     According to still another characteristic of the invention the rigid connecting rod assemblies present, for their assembly on the crank pins of the cast solid crankshaft, lights open on a side, a removable hat ensuring the closing of each known as light once the connecting rod assembly placed on the crank pin. 
     The crankshaft, like the rigid connecting rod assembly, is soaked and receives a surface treatment very hard and self-lubricating. Aquaplaning as well as the presence of hard surfaces self-lubricating make it possible to ensure a long operation life. 
     According to another characteristic of the invention, the connection of the crank pin with the light of the connecting rod assembly can be carried out in various ways which include: 
     the use of a split ring assembled on the crank pin and which plays the part of roller, 
     a direct contact of the crank pin on the connecting rod assembly thanks to a very hard and self-lubricating surface treatment, deposited on soaked surfaces, which combines with aquaplaning. 
     According to still another characteristic of the invention, the stages of connecting rod assembly are assembled without sealing so that the running clearance of these stages makes it possible for the gas under pressure below the pistons to pass towards the interior of the casing while putting says it casing under pressure of air and by driving out oil being in the casing by a drain equipped with a non-return valve. 
     One can thus function &lt;&lt;dry casing&gt;&gt; without having to use of cam in the casing. The oil thus driven out of the casing is collected in a tank from where it is then pumped to put in pressure the circuit of lubrication. 
     Advantageously, the oil cam ensuring the pressurization of the circuit of lubrication is incorporated in the injection cam. This provision allows a simpler design of the engine, the cam oil being accessible from outside what facilitates any intervention relating to it. 
     According to still another characteristic of the invention, the injection cam is coupled directly in end of crankshaft, and this last is prolonged by the injection cam shaft which can be equipped with a pulley to actuate an alternator or a cam. 
     According to another characteristic still of the invention, to facilitate cooling without losing reliability, the cylinder head is out of high-strength hammered steel, whereas the other components of the engine contained by the cylinder head are out of aluminium. It is the cylinder head which heats more, but the grade of the steel used allows that it does not become deformed. The cooling of the cylinder head is mixed: a cooling by oil with a circulation around the ring, and an air cooling whose flow sweeps the cylinder. This cooling can also be water/oil, or even oil/oil in order to have one radiator of cooling. 
     The cylinder head is fixed in a multitude of points so that the pressure is regularly held on all its periphery. This cylinder head, made out of steel, shim compressed the aluminium components of the engine and prevents that they become deformed. 
     It is understood that the engine according to the invention, incorporating the characteristics above mentioned, has the advantages of a strong profit of weight, of a profit of appreciable volume, a low cost, low fuel consumption, a weak heating, a weak pollution and a great reliability. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For rendering comprehensible well the invention one will describe some hereafter, as an example without restrictive character, a form of execution preferred in reference to the annexed diagrammatic drawing in which: 
     FIG. 1 is a horizontal cut of an engine flat and with cylinders opposed according to the invention, this cut being taken by the mating plane of the two half-casings of the engine; 
     FIG. 2 is, on a large scale a sight in section of a cylinder of the engine; 
     FIGS. 3 and 4 are, on a large scale, a sight in section and a sight in plan, respectively, of a stage of attachment equipping the engine with FIG. 1; 
     FIGS. 5 and 6 are, also at greater scale, a sight in section and a sight in plan, respectively, eduction valve box; 
     FIG. 7 is a sight in section, on a large scale, of a sleeve of a cylinder of the engine; 
     FIG. 8 is a sight of detail in end of the paddles present on the sleeve of FIG. 7; 
     FIG. 9 is a sight of top, partially in section, of a rigid connecting rod assembly of the engine of FIG. 1, this connecting rod assembly being represented open; 
     FIG. 10 is a side sight corresponding on FIG. 9; 
     FIG. 11 is a sight in section of the hat intended to close the rigid connecting rod assembly of FIGS. 9 and 10; 
     FIG. 12 is, on a large scale, a sight burst out in cut of a piston of the engine of FIG. 1; 
     FIG. 13 is a sight in plan of the ring seal assembled on the large diameter of the piston and its internal shim associated; 
     FIG. 14 is a sight in plan of the ring of exhaust and its associated external shim; 
     FIGS. 15 and 16 are respectively a sight in section and a sight in plan of a cylinder head associated to a cylinder of the engine; 
     FIG. 17 shows a roller intended to be interposed between the rigid connecting rod assembly and the crank pin of the crankshaft; 
     FIG. 18 is a detail sight of FIG. 17, showing cuttings of the roller facilitating the closing of the aforementioned by joining, on the crank pin, and 
     FIG. 19 shows an alternative of a piston. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In reference on FIG. 1, one represented into  1  a half-casing of an engine including four cylinders flat, opposed two to two. Each cylinder  2  is in support on a side on half-casing  1  by means of a stage of connecting rod assembly  3  and an eduction valve box  4  and other side against a cylinder head  5 . Openings in glance  6  spared on the periphery of the cylinder head  5 ,  7  spared in the cylinder  2 ,  8  spared in the eduction valve box  4  allow the passage of pins or screw  8 ′ to block the unit formed by elements  5 ,  2 ,  4  and  3 . 
     Crankshaft  9  passes in a central stage  10  and is guided by bearing liners  11 . Crankshaft  9  is bored by drains of large diameter  12  which are used to reduce the crankshaft and which meet in the medium of the central stage  10  from where arrives of the lubricant under pressure by a hole  13  which corresponds with a throat formed between bearings  11 . Thrusts  14  make it possible to position crankshaft  9  and to support the pushes, whereas the sealing of the stages is ensured by sealing rings  15  which center half-casings  1  with bearings  11  around crankshaft  9  in a plan. 
     Each cylinder  2  internally wears a sleeve  16  with which a piston  17  cooperates, and two opposite pistons  17  are connected together by a rigid connecting rod assembly  18  of which the central part is in direct contact with a crank pin  19  of crankshaft  9 . Jets  20  of crank pins  19  sprinkle with lubricant the plane faces of connecting rod assembly  18  which are in contact with crank pins  19 . 
     Surfaces in friction of crankshaft  9  and connecting rod assemblies  18  are hardened thermically and covered with a surface treatment very hard and self-lubricating. This treatment constitutes a guarantee of reliability because it makes it possible to work dry with starting, or in the event of lack of oil. 
     Connecting rod assemblies  18  are positioned in casing  1  and on crankshaft  9  by the stages of connecting rod assembly  3  whose central residences  21  guide perfectly these connecting rod assemblies  18  in two opposite points on both sides of casing  1 . The play between the stages and the stems  22  of connecting rod assemblies  18  is very weak, about 0,02 to 0,04 mm. Guidance is also done with the side faces of the rigid connecting rod assemblies  18  in support against the con-rod axle crank face  19 . 
     Two opposite pistons  17  are perfectly centered with the stems  22  of the connecting rod assemblies  18 , by screws  32 , so that these two pistons  17  assembled on a connecting rod  18  form nothing else that one rigid and perfectly centered part. 
     As one sees it on FIG. 1, the cylinder head  2  ends in a truncated cone  2 ′ whose top determines, with the end of emerging piston  17  coming from this cylinder, an exhaust light  3 ′ which is closed before the lights of transfer  58 . With the closing of the exhaust port  3 ′, the gases which move at very high speed crush and densify very strongly in the top of cone  2  ′ of the cylinder by producing a strong depression on the level of the lights of transfer  58  which are still open. This depression starts a second air inlet in the same driving cycle by producing an important overfeeding which lasts until the closing of the lights of transfer  57 . 
     Piston  17  present on its large diameter a cone  17 ′ identical to the cone  2 ′ of the cylinder  2  and which is prolonged, towards the small diameter of the piston, by a machining which determines an annular combustion chamber  60  when piston  17  arrives at the point died high. 
     This annulus  60 , variable and appreciably triangular section, allows a variable thickening of the air-fuel mixture. For an operation in weak mixture, a sufficient thickening with a good lighting always occurs in the high part of the combustion chamber  60  on the level of injector  42 , which makes it possible to light all the mixture remaining, even if the aforementioned is very low in carburizing. 
     As one more particularly sees it on FIG. 12, piston  17  is made of two parts  23 ,  24  which take in sandwich an internal shim  25  and one ring seal  26 . The part  23  of the piston presents an interior room  27  cylindrical continuing at an end by a cylindrical boring  28  coming in glance from a central cylindrical housing  29  from the part  24  of the piston. At its other end, room  27  is closed by a stopper  30 . 
     At the interior of room  27  a screw  31  is presenting a rectified cylindrical part  32  which centers two parts  23 , 24  of piston  17  and fixes it  25  of ring  26  with the stems  22  of connecting rod assembly  18  (see FIGS.  9  and  10 ). The interior face  33  of screw  31  is also rectified to ensure the sealing between this screw and the part  23  of the piston. As one will further see it, room  27  is intended to contain a coolant, and stopper  30  ensures the tight closing of this room. 
     The small diameter external  34  of the part  23  of piston  17  is perfectly concentric with boring  28  and, on this diameter  34 , only rubs a ring of exhaust  35  which will be described further. 
     Large diameters  36 , 37  of parts  23 , 24  of piston  17  are assembled with much play so that they do not touch sleeve  16 . Only ring  26  is in contact with sleeve  16  of cylinder  2 , which is made possible thanks to the guidance and the perfect centering of the parts between them. 
     With FIG. 13, one sees ring  26  ensuring the sealing by his external diameter  38  between piston  17  and  16  line it. The shim  25 , which is centered by screw  31 , rule the play of ring  26  in height, by allowing an assembly floating of this ring in the throat determined between the parts  23  and  24  of piston  17 . 
     Thus the ring  26 , which is mobile with piston  17 , ensures him only a perfect sealing and of long duration with sleeve  16 . 
     According to an alternative represented on FIG. 19, piston  17 ′ is made out of aluminium covered on the surface of an insulating ceramic layer of great hardness (2400HV). The interior of the piston, which does not contain any more fluid, is open with a nose bullet radiated on the small diameter to facilitate the penetration of ring  35  assembled with tightening on the interior diameter  44 . 
     In reference on FIG. 2, one represented cylinder  2 , presenting at an end a centering  39  for cylinder head  5  and, at his other end a centering  40  in the eduction valve box  4 . The bottom of centering  39  includes an annular throat  41  with semicircular section in which the oil of lubrication and cooling circulates. 
     In cylinder  2 , one represented into  41 ′ the housing of a fuel injector communicating by an opening  42  with the higher part of the interior volume of cylinder  2 . The axis of the injector is tangent with the small diameter of piston  17 , the injection being done in the direction of rotation of gases. The injector is located in top of room  60 , in order to carry out an injection in two times so necessary with a larger density of fuel in the top of the conical part of the cylinder. 
     In the part of centering  39  of cylinder  2  are laid out, as represented on the FIG. 14, the ring seal  35  and fixes it  43  laid out concentrically outside this ring. Ring  35  fact the sealing, by its interior diameter  44  on small diameter  34  of the piston  17 . This ring  35  is static and it is centered by diameter  34  of piston  17 . The shim  43 , which regulates the play in height of ring  35  is centered by cylinder  2 . 
     Between shim  43  and ring  35  is formed an annular throat  45  which corresponds with throat  41  in cylinder  2  and with a throat  46  in cylinder head  5  (see FIG. 15) to form an annular throat of strong section and having an important heat-transferring surface. In this throat circulates the oil of lubrication of ring  35  and cooling of the top of cylinder  2  and cylinder head  5 . This oil escapes then towards a cooler (not represented) which is also used as oil tank. The exhaust of oil is regulated by a throttling which defines the oil pressure with which the engine functions. 
     The ring of exhaust  35  is made of two superimposed discs crossed into  35 ′, for their positioning, by two small pins a length higher than the thickness of the discs and which are placed in two holes spared in the cylinder. This provision is essential for the engines of four cylinders or more, in which a ring seal is always released with the stop, by preventing this ring slipping and from making a thrust with the piston during starting. The end of small diameter of piston  17  presents towards the outside a round-off  23 ′ making the nose bullet of piston  17  in the ring of exhaust  35 , facilitating the introduction of the piston into this ring. A weak play is always envisaged on the pins to keep the floating rings. 
     Attachments  18  guide perfectly the pistons which are assembled with an important play compared to the sleeve and with the cylinder correspondents, so that there is no friction piston/sleeve. Only rings  35  and  26  are in contact to ensure the sealing. 
     In reference on FIGS. 15 and 16, one represented cylinder head  5 , having surfaces of contact  47  with the ring  35  and his shim  43 , which are well ground to ensure a good sealing, as well as centering  48  with part  39  of cylinder  2 . The cylinder head presents radial fingers  49  bearing openings  6  of passage of the latch-tightening screws, with supports  50  of these screws. This form with fingers  49  ensures a better cooling of cylinder head  5  as well as a reduction of the aforementioned. 
     Cylinder head  5  is manufactured in a steel with high mechanical characteristics hot, so that it does not become deformed. 
     On FIGS. 3 and 4 one represented a stage  3  for the connecting rod assembly  18 , whose external diameter  51  (as one sees it on the FIG. 1) ensures the positioning of half-casings  1  in a plan. Stage  3  presents a face of support  52 ′ for the sleeve  16 , which blocks the stage on casing  1 . Radial peripheral residences  53  are intended to receive springs  54  (see FIG. 1) operating valves  55  of the eduction valve boxes  4 , which slip on face  52 , whereas central housing  21  of two stages  3  in glance guides a connecting rod assembly  18 . 
     On FIGS. 5 and 6 one represented an eduction valve box  4  which is centered by its interior diameter  56  on stage  3 . The eduction valve box  4  presents, regularly spaced on its periphery, eight openings inlet  57  which, with diameter  56 , are used as seats with valves  55  (FIG. 1) which are positioned by springs  54  in support in housing  53  of stages  3 , and by their longitudinal slip on face  52  of stage  3 . 
     The inlet openings  57  are conical to facilitate the passage of the air and, between these lights  57 , pass orifice  8  of the assy screw  8 ′. 
     In reference on FIGS. 7 and 8, one sees sleeve  16  of the cylinder  2 , whose columns  59  of the lights of transfer  58  have the shape of static paddles which print a rotational movement to the air which engages there at high speed, this air turning like a cyclone around small diameter  34  of piston  17 . The interior volume of cylinder  2  is reduced with the rise of piston  17 , to form the combustion chamber  60  when the piston is at its point died high. 
     It is noticed that face  61  of sleeve  16  is resting against cylinder  2 , whereas its face  62  is resting against stage  3 . 
     Sleeve  16  is assembled with tightening over its length in order to block stage  3  in correspondence with the lights of the eduction valve box. 
     Sleeve  16  received a surface treatment very hard and self-lubricating. 
     On FIGS. 9 and 10, one represented the opened rigid connecting rod assembly  18 , equipped with his two axes in alignment  22  which guide it in stages  3 . The faces of support  63  of connecting rod assembly  18  are intended to rub on crank pin  19  of crankshaft  9 , whereas the faces of side guidance  64 , parts  65  of fixing of the pistons, centerings  66  and supports  67  cooperate with the perfect centering of pistons  17  and the stems  22  of connecting rod assembly  18 . 
     Connecting rod assembly  18  is represented opened, to allow the introduction or the shrinking of the crank pin of the crankshaft. On each side of the open part of the connecting rod assembly, grooves  68  cooperate with fixings  69  to close the connecting rod assembly by means of hat  70  with semicircular section represented on the FIG.  11  and which gives to the connecting rod assembly the rigidity of a cast solid attachment. As one sees it with this FIG. 11, hat  70  present of the grooves  71 , which are assembled without play in grooves  68  of connecting rod assembly  18  and residences  72  being used for the passage of fastening screws not represented. 
     In alternative, as one sees it on FIGS. 17 and 18, one represented another form of connection between a connecting rod assembly  18  and one crank pin  19 . To this end a ring  73  is interposed between the crank pin of the crankshaft and the connecting rod assembly, in order to remove direct friction between these the last two elements. 
     This steel ring is covered with a hard and self-lubricating surface. After manufacture, ring  73  is cut out by electroerosion with the wire, to allow its assembly on the crank pin, then the slit left by the wire is filled with the assembly by an adhesive of structure which makes the ring cast solid and that cannot be taked to pieces. 
     As one sees it in particular on FIG. 18, the two cuttings separating parts  74  and  75  of ring  73  form a key which locks two half-rings  74 ,  75  after joining between them. 
     Ring  73  is around crank pins  19  and rolls on the tracks of connecting rod assemblies  18  as the wheel of a train on its rail. 
     Another form of connection, already known by itself, would consist in using shoes. 
     The balance of the engine describes above is regulated by the crank pins  19  of crankshaft  9  which are fixed to 90° 0  one compared to the other, so that an explosion occurs with each rotation of 90° of the crankshaft. These explosions occur by auto-ignition when piston  17  is at the point died high, with a pressure of approximately 30 bars. However lighting can also be controlled with a lower pressure, for example for an operation with gases. 
     The injection in room  60  is carried out into  42  and the explosion propels the unit made up of a connecting rod assembly  18  and two pistons  17 , by ensuring the drive of crankshaft  9  by crank pin  19 . The inertia of connecting rod assembly  18  is cancelled by withdrawing compressive forces of precompression, aspiration and, to transmit a force higher of 30% approximately than that transmitted by a conventional connecting rod assembly articulated under the same conditions. 
     In the engine describes above and represented on FIG. 1, one sees that there are only three moving parts moving, which are the two connecting rod assemblies  18  and crankshaft  9 , as well as the valves  55  which are thirty two. 
     One will notice the presence in the engine, according to the invention, of a great number of identical component. As follows: 
     four stages of connecting rod assembly  3 , 
     four eduction valve boxes  4 , 
     four sleeves  16 , 
     four cylinders  2 , 
     four rings of exhaust  35 , 
     four rings of admission  26 , 
     four cylinder heads  5 , 
     four pistons  17 , 
     two rigid attachments  18 , 
     thirty two valves  55 , 
     thirty two springs of valves  54 , 
     six half bearings of stages  11 . 
     The same elements are used for construction of engines having 2,4,6,8 or 10 cylinders, only different half-casings  1 , crankshafts  9 , the intake manifolds (not represented) placed on the eduction valve boxes  4 , the injection cam, the wheel and the dummy crank-case. 
     It will be understood that the description above was given to simple title of example, without restrictive character, and that constructive additions or amendments could be made there without coming out of the framework of the invention. 
     It will be understood in particular that, without leaving the framework of the invention, one could produce a radial engine, with four cylinders laid out around a casing of square section, with a cylinder all the 90° and one crankshaft with only one crank pin on which two rigid connecting rod assemblies placed are assembled side to coast and 90° one compared to the other. 
     The stacking of the parts would be then the same one as on an engine flat according to the invention and operation would be identical. To increase the rigidity of the tubular casing, the aforementioned would then be closed with each end by flasks whose edges would cover each end of the casing. The casing thus would consist of three parts, which are a cast solid tubular casing and two flasks forming lids which are used as stages for the crankshaft.