WO1993008390A1

WO1993008390A1 - Total injection type internal combustion engine with exhaust gas heated compressed air

Info

Publication number: WO1993008390A1
Application number: PCT/FR1991/000794
Authority: WO
Inventors: Gérard Hervier
Original assignee: Hervier Gerard
Priority date: 1990-10-18
Filing date: 1991-10-14
Publication date: 1993-04-29
Also published as: FR2668199B1; FR2668199A1

Abstract

Internal combustion engine of the piston type for a motor vehicle, powered by a separate compressed air supply which is injected into each cylinder after having being heated by the exhaust gases. The invention relates to heat exchange and gas distribution means, its connection to the cylinders and the new configuration of the chamber and of the pistons. It is comprised of a frustroconical rotating distributor (15) pushed against a bore (5), having the sameconicity, by the pressure of the air on the intake pipe (18), and linked to each cylinder by a gas-transfer pipe (6). Heat exchange take place in three steps: first, preheating in the cells (7) of the timing case (3), then in the fixed exchanger (8) and finally in a rotating heat exchanger (16) arranged between the rotor (15) and the intake pipe (18). The accelerator pedal controls the air intake by means of a valve (10) and varies the volume injected by means of the angular offset of the rotor (15) with respect to the crankshaft. Fuel injection is regulated so that the temperature of the burnt gases is optimal.

Description

TOTAL INJECTION TYPE INTERNAL COMBUSTION ENGINE WITH HEATING OF AIR COMPRESSED BY EXHAUST GASES

The invention relates to an internal combustion piston engine, more specifically intended for the automobile, the fundamental difference from which is compared to current engines is that the air is not compressed in the cylinders where performs combustion but comes from a separate compressed air production unit. This type of engine, which operates on a two-stroke cycle, has sometimes been called "TOTAL INJECTION ENGINE" because it injects, under pressure, both the fuel and the oxidant. In fact this engine has not spread because, in order to gather all the advantages that it can offer in theory, we run up against great technical difficulties; in particular it is necessary, before its admission, to bring the air to the highest possible temperature, by recovering the heat of the exhaust gases, and to distribute with the minimum of losses the very hot gases entering and leaving the cylinders.

The present invention provides a set of original technologies so that such an engine can operate with optimum performance; it only concerns the engine itself and implicitly assumes the existence of a unit which will supply it with compressed air; it is not the subject of any description or claim here.

The advantages brought by this new motorization of the vehicles can be considerable; the most striking aspects concern consumption, fuel, pollution, behavior and ecology. The significantly higher yield and the reduction in losses lead to a significant drop in consumption under all market conditions and especially in urban traffic. The choice and composition of the fuel requires far fewer constraints; there is no need for a detonating or other additive; it is possible without mixing or substituting synthetic alcohols for the hydrocarbons. Combustion is cleaner and more complete because it is similar to that of a gas burner with high excess air; pollution due to discharges of unburnt, soot and carbon monoxide is practically eliminated. One can easily make this self-starting engine with direct control by the accelerator pedal; as soon as the support for air and fuel is stopped, it is immediately stopped; this elimination of unnecessary discharges, if it were generalized, would considerably clean up the atmosphere of congested urban areas. Finally, this engine is particularly well placed to promote, in the medium and long term, ecological fuels, from vegetable sources only, with a view to rebalancing the cycle of carbon dioxide on earth destroyed by the overconsumption of fossil fuels. The following description is in two parts; in the first, by referring to the diagram in FIG. 1 and to the diagrams of FIGS. 2 and 3, we will focus above all on the theoretical and fundamental aspects of this engine, on the conditions to be fulfilled to optimize performance, on the essential elements that make it up. The detailed description of the different parts and techniques used is the subject of the second part; the drawings with reference to FIGS. 4 and beyond are more particularly adapted to the most common version of this engine, that is to say that of two cylinders; it is understood that the claims apply to all adaptable versions of this engine. Many of the components are identical to those which exist in known current engines; the description which follows will be attached only to the new organs of this engine and to the particular modifications of these current components.

Figure 2 shows the theoretical engine gas circuit. In the countercurrent exchanger the compressed air is brought to high temperature by the burnt outlet gases, the distributor transfers the gases entering and leaving each cylinder. On the pressure and volume diagram, the cycle of successive transformations in the chamber of a cylinder has been plotted, for various states of charge, during the round trip of the piston. The points separating each phase are identified by a letter. The diagram in Figure 3 gives the angular position of the crankshaft for each of these points. H and B are the top and bottom dead centers; VH and VB the corresponding volumes. The cycle includes the following phases:

_ (Y H A) INTAKE: the air first fills VH then through the isobar HA an additional volume which varies with the angular position of point A set by the distributor.

_ (A C) COMBUSTION: the fuel is injected so that combustion begins a little before A, which is as short as possible and leads to an increase in both temperature and pressure. _ (C D) RELAXATION: this transformation is close to an adiabatic; the final pressure is higher the greater the volume at A.

_ (D B E) EXHAUST: upon opening the distributor, there is a sudden expansion of the gases; the energy of the transfer is supplied by the gas itself and therefore causes the temperature to drop. _ (E R) DELIVERY: it takes place at almost constant pressure and temperature; the piston provides the transfer work.

_ (RYH) RECYCLING: between the end of the delivery and the start of the intake, the distributor creates an isolation zone; the small mass of gas that is enclosed in R is recycled and compressed to the pressure of the intake air.

On the diagram in Figure 3 the hatched phases are those where the chamber must be isolated by the distributor. In common engines, the compression ratio is the most important parameter for performance; which requires working there at very high pressures. In the cycle described above, a very good yield is obtained even with a moderate pressure of the intake air, for example that commonly supplied by a single-stage volumetric compressor. Here it is the temperature of the admitted air which is the major parameter and it is the resistance of the materials in direct contact with the exhaust gases which will set the limit. It is advantageous, in order to optimize, at all times, the thermodynamic efficiency of the engine to regulate the gas outlet temperature to the maximum admissible value, by acting on the quantity injected of the fuel. Consequently the work provided during the cycle and consequently the torque delivered is practically proportional to the mass of air admitted.

On the solid line cycle described above, this mass is maximum when the end of admission angle A is the greatest; but it should be noted that the higher the torque, the more the trigger will be truncated and will bring about a significant drop in efficiency.

When point A is at its minimum position, close to H, the trigger

CD is complete; the cycle drawn in phantom is obtained which corresponds to the most economical torque for using the engine; it is advantageous to fix the volumes VB and VH so that this torque is statistically most often used in driving the vehicle.

The last cycle plotted on the diagram, in dotted line, is used to give the weakest torques necessary for displacements at low speed; here the admitted volume remains blocked at a minimum, that is to say at a value close to VH, and the admitted mass is reduced by reducing the pressure by throttling the intake valve.

Compared to the different versions of DIESEL engines in service, the injection and combustion problems of this engine are easier to control for the following reasons: _ injection can be done at moderate pressure; _ a fuel more volatile than diesel will be burned there and which will vaporize instantly after injection;

_ the very high temperature prevailing in the chamber will greatly reduce the ignition time and eliminate the explosive combustion phase. Figure 1 presents a simplified image of the engine components and explains the main aspects of its operation. A casing (3) is clamped by its plate (4) against each cylinder (2) and communicates with it by a conduit (6) used for the transfer of gases. A rotating assembly, driven by the villebrequin using the transmission (14) is enclosed in this casing; its primary role is to ensure the distribution of gases with the cylinders by means of a rotor (15), of frustoconical shape, coming to bear against a bore (5), of the same taper machined in the casing. The external conical surface of the rotor carries at least one orifice (19) for the injection of air and an orifice C20) for the expulsion of the burnt gases. The conduit (6) opens into the bore through a narrow orifice; the gas is transferred at each passage of the mobile orifices (19) and (20) in front of it. The rotating assembly also performs the final phase of the transfer of heat between the burnt gases and the air by means of an exchanger (16) arranged as an extension of the rotor and conveying the air therein by a nozzle (18). ; the exchange surface is enlarged externally by projecting parts (17) which rotate in the direct flow of gases.

At the end of the housing is fitted a tight rotary connection with a fixed part (9) in which the end piece (18) slides; this connection brings a thrust force which can be adjusted to a fixed and precise value by the choice of the section. This is essential for the proper functioning of the distribution; in fact the rotor (15) itself receives forces due to the pressure of the gases which tend to move it away from the bore (5); to ensure contact, the opposing thrust on the end piece (18) is established at the level just necessary. This technique allows, on the one hand to reduce leaks to the distributor, on the other hand to let filter between the conical surfaces a microscopic gaseous film sufficient to greatly lower the coefficient of friction and prevent abrasion or seizure.

The air from the source (1) first fills the partitioned chamber (7), arranged in the distribution stator, that is to say in the part of the casing which surrounds the rotor. During its passage in the stator the air is preheated; thanks to the heat thus evacuated the stator can be maintained at a moderate temperature level. The second phase of air heating takes place in a fixed exchanger (8), against the flow of the exhaust gas flowing from the exchanger (16).

The motorized valve (10), preferably arranged on the air circuit between the two exchangers, is controlled by the accelerator pedal (11) and controls the starting or stopping of the engine. We now turn to the second part, focused on the concrete presentation of a two-cylinder version of this engine. The main part of this description will relate to the completely new member thereof, which performs all the operations of air heating and gas distribution, and somehow replaces several well-known elements such as the cylinder head and its inlet and outlet manifolds, starter, exhaust silencers. This organ is quite long and voluminous; its overall longitudinal view, which is a section along a plane passing through the central axis, for greater clarity, is distributed over two figures; Figure 5 where we see the exchangers and the inlet valve integrated at the end, and Figure 7, which shows the distribution block connected on one side to the exchangers and the other to the drive device. The other overview, offered by FIG. 4, is a cross section passing through the axes of the cylinders; it will describe the transfers between the distributor and the cylinders as well as the specific arrangements made for them and for the pistons. In addition to these general views, reference will be made, during the description which follows, to a few additional or detailed views as well as to two operating diagrams; one, Figure 11, relates to the entire control of the air intake by the accelerator pedal; the other, FIG. 12, proposes an overall arrangement for the injection of fuel more specially adapted to this type of engine.

The rotor (15) rotates at half the speed of the crankshaft and has two holes (19), opposite by the diameter, for the injection of air and likewise two holes (20) for the expulsion of gases. This arrangement balances the radial thrusts on the rotor. The duct entry slots (6) are offset by 90 degrees. The cylinders (2) are arranged in parallel with alternating movement of the pistons. The two-stroke cycle described above is carried out successively in each cylinder with a phase shift of half a turn of the Villebrequin. Thus we can see, in Figure 4, that the left piston has started its descent and that we are at the end of the intake phase; on the opposite side, the right piston rises and expels the gases.

The distribution stator (21) is a fairly massive foundry piece whose plate (4) acts as a cylinder head for the cylinders which are clamped between it and the motor casing by tie rods. The bottom of the plate (4) is machined so that the cylinders come to be embedded there by enclosing a wafer (24), made of ceramic, pierced in the center of a round hole in which the end of the conduit (6) . Each side of the plate (4) has a row of threaded holes (22), opening at the end of the duct (6), and used to fix the combustion control elements (injectors, spark plugs, temperature gauges). The entire casing of the stator (21) around the conical bore (5), with the exception of the passages (6), is filled by cells (25) in which circulates the supplied fresh air; their exchange surface and their internal volume are sufficient to maintain the entire mass of the stator at a moderate temperature.

Each cylinder, a cross section of which can be seen in FIG. 9, consists of a cast iron body (2), furnished at its periphery with longitudinal grooves (30), and enclosed in a welded steel ferrule (31) or crimped at each end. Through the tubultires (32) a coolant which can advantageously be pressurized water is circulated in the grooves (30). Each piston consists of an aluminum alloy body (13) on top of which are stacked an elastic flat washer (28), an insulating plate (27), and finally a ceramic cap (26); these three parts are pressed against the piston by a flange (29), made of very refractory steel, carrying the upper sealing segments, and fixed to the piston by its lower skirt. This particular piston isolation technique is possible in this engine because the pressure exerted on the cap (26) is low. On the other hand, it is necessary to cool the collar (29) separately so that it can withstand the extreme temperatures of combustion; for this, a forced circulation of cooled oil is established between the piston and the walls of the cylinder; the oil is discharged by the engine pump into a small conduit (33) opening out in the middle of the cylinder at a point always situated between the top and bottom sealing segments; the oil comes out through a row of small holes emerging flush with the piston vault after having ^" crossed skirt and wall. At top dead center the cap (26) fits with very little play in the flared profile of the wafer (24), so that the volume of the chamber is practically equal to that of the duct (6); when the piston begins to descend, the air admitted into the duct (6) is forced to pass at high speed through the narrow annular space existing between the ceramic pieces; the fuel is injected at the entrance of this space and there is a very rapid and efficient mixing of the constituents. The temperature and the radiation which reign there are particularly high; this favors the immediate and complete combustion of the gas mixture.

Heat transfer in the rotating part is mainly done through a bundle of steel tubes (34) lined over its entire length with radial fins (35); these are large diameter washers, in thin sheet metal, fitted on the tubes, in order to increase the contact surface with the burnt gases, while stiffening the bundle. At each end the washers are replaced by thick flanges (36), soldered on the tubes, and embedded on one side in an air intake box (37) and on the other in the rotor (15), these two parts being interconnected and pressed against the beam by a central axis (38) provided with a tightening nut (39). To achieve maximum efficiency in the exchanger, the burnt gases are forced to go back and forth between the center and the periphery, each time passing through the bundle of tubes. This movement is obtained on the one hand by stacking on the axis (38) ceramic deflectors (40) which create a series of rounded grooves, on the other hand by placing partitions in the desired places, in place of the fins. of two types; some (41) prevent outside passage and force the gases to return to the center; the others (42) close the passage in the center by pressing against the deflectors (40). These are brought to a very high temperature and create intense radiation towards the exchanger; their internal profile is arranged to have the minimum contact with the axis (38); it is preferable that it is hollow and that a light air flow is circulated there.

The fixed exchanger is arranged all around the rotary exchanger and completely encloses it, as can be seen in the cross section of Figure 6. It comprises a main body (43), preferably cast in a good conductive alloy , provided with external longitudinal grooves (44) and internal (45), an external cylindrical casing (46) in steel and an internal ferrule (47) in stainless steel. On the valve side, the body (43) and its casing (46) close towards the center; distribution side, the enclosure ends with a flange which makes it possible to fix the entire heating block, with a sealed socket, to the front face of the stator (21). The air, at its outlet from the cells (25), is channeled in the grooves (44) upstream of the valve (48) of the valve. The burnt gases, after their last passage on the bundle (34), penetrate into the internal grooves (45) by a circular space at the end of the ferrule (47); these gases, after having yielded most of their initial heat, emerge at the other end of the fixed exchanger by a series of holes through the body (43) and the envelope (46), as shown in the view in section of Figure 8; these gases are then channeled through a sheath (57) to the outside.

The normally closed type air intake valve is fixed and centered at the end of the exchangers; the opening of the valve (48) is obtained by sending pressurized air into a jack comprising a body (50) and a piston (51) connected to the valve. The valve body (52) is fitted at the end and in the center of the fixed exchanger (43); it comprises the seat and the valve guide (48) as well as the axis on which the housing (37) rotates. The cylinder body (50) has a flange which allows the end of the casing (46) to be tightly tightened against the valve body (52); the studs (53), machined on the front face thereof, ensure centering while letting the air pass upstream of the valve.

The pressure prevailing downstream is a linear function of that existing in the cylinder; this valve can therefore be used as an intake pressure regulator; to have the same pressure downstream as upstream, this pressure must also be maintained in the cylinder. This whole device has no spring and is capable of operating at the relatively high temperatures prevailing there.

When the valve opens and the downstream pressure increases rapidly, the intake air acquires a high speed for a short time. It is advantageous to use the corresponding kinetic energy to trigger the first rotations of the motor, in the desired direction; it is then able to continue its startup alone. For this, on the radial path of the movement of air towards the inlet of the housing (37), there is a diffuser (54) and a small turbine (55) which can be seen in cross section in FIG. 6. The diffuser (54) is integral with the body (52) and comes in extension of the axis of the bearing. The turbine (55) is itself integrated into the housing (37) which can be cast in one piece, for example in an alloyed cast iron. The distribution rotor (15) has an internal partitioning which separates the intake air and the burnt gases and contributes ^" efficiently to the transfer of heat between them; working permanently at very high temperature it must be cast in an alloy refractory or formed in a ceramic material In the figure the sectional view has been arranged in order to show the passage for the exhaust (58) at the top and the passage (59) for the air intake at the bottom.

The air leaving the bundle of tubes (34) first fills the circular cavity (60) of the front face, then the two intake ducts (59), finally a large central spherical cavity (61) extended by a nozzle. in which the hollow axis (38) is fitted. The total volume of air accumulated in the rotor is relatively high compared to the volume injected into each cylinder; this limits, in part, the pressure drop following the very short duration of this injection. The cavity (61) is closed at the rear by a cover (62), made of steel, welded to the shaft (38) and extended by a shank provided with a conical bearing and grooves, used for driving the entire rotating assembly.

Fresh compressed air from the central unit enters the stator (21) through a side inlet and first fills the entire circular internal cavity (99); it then crosses the cells (25) and exits towards the different grooves (44) of the fixed exchanger. The entire outer surface of the stator and the casing (46) is covered with insulation. On the rear side of the stator is fixed an insulating ceramic plate with a central bore for the passage of the drive. The latter is designed to minimize heat loss and the temperature of sensitive rooms. It includes a pulley (56), driven by a toothed belt, rotating in a bearing (64), itself held by a support (65) fixed to the stator near the air inlet, where the temperature is the lower. These rooms, visible in the rear view of Figure 10, are largely ventilated by the ambient air. The support (65) is fixed with precision, for example with centering shoulder screws, so that the axis of rotation of the pulley (56) coincides with that of the distributor. The coupling between these last two parts is obtained by a wafer (66), of highly insulating ceramic material, riveted on a steel hub (67) itself secured to the tail of the cover (62). The wafer (66) is driven by parallel axes (68), integral with the pulley (.), And on which it can slide axially under the action of the springs (69) placed on these same axes. During operation, the thrust of air from the end bearing compresses these springs; when stationary, they push the rotating assembly against the stop (49) and create a small space between the conical surfaces of the rotor and the stator; the cylinders can breathe and there is no more friction; the engine runs idle on its momentum and to stop it you have to use external braking. The springs (69) hold the pulley (56) against the bearing (64) which will preferably be of the ball and angular contact type.

FIG. 11 shows, advantageously gathered in the same housing (70): a servo-valve which controls the pressure of the jack (50) of the intake valve, a drive device, with phase shift, of the driving pulley (71 ) which itself drives the distributor at half the speed of the crankshaft, finally the associated control of these two elements by the cable (72) of the accelerator pedal.

The servo valve includes a drawer (73) sliding inside a free piston (74) which receives on one side the thrust due to the air pressure in the chamber (75) and on the other the force of a spring (76). The depression of the drawer opens a passage for compressed air to the chamber (75) and the piston moves as long as the pressure there is sufficient to compress the spring (76). Conversely if the drawer is allowed to retreat, by the effect of its small return spring (77), the air in the chamber escapes through the passage created at the end of the drawer and the pressure drop causes the piston to return. The latter therefore faithfully follows the movement of the slide valve and to each position thereof corresponds to a precise value of the pressure relaxed downstream of the intake valve. The spring (76) is calibrated so that this pressure is maximum at the end of the slide stroke and corresponds, at the start of the stroke, to the minimum engine torque sought. At rest the cylinder (50) is vented and the valve is naturally closed.

The pulley (71) is driven by a pair of helical pinions with perpendicular axis and of the same diameter, one (78) fixed and integral with the crankshaft, the other (79) mobile and capable of being move axially on a splined shaft (84) integral with the pulley (71). A pusher (80), sliding in a cover (81) fixed to the housing (70), comes to rest against a bearing (82) fitted at the end of the pinion (79). This movable assembly is pushed back towards the cover by a spring (83) which bears on the bottom of a shaft cavity (84). This whole mechanism is lubricated by engine oil. When the plunger (80) is pressed while compressing the spring (83), an angular phase difference occurs between the two pinions which creates an advance to the distributor and the volume of air admitted increases with the angle of end of admission.

The pulley (71) is fixed to the shaft by a conical fitting, which is blocked by tightening, with the toothed belt in place, after having carefully positioned the distributor with respect to the pistons. The rondel¬ the spring (85) serves to hold the shaft (84) against its bearings. The traction of the cable (72) by the accelerator pedal is exerted on a lever (86) articulated on one side at the end of the pusher (80) and on the other at that of the drawer (73); the latter sinks first because it requires very little effort; when it reaches the end of its travel, the pusher (80) sinks in turn, requiring greater effort, because of the spring (83) -and the reaction of the teeth. The torque delivered by the motor increases regularly over the entire pedal travel; the position corresponding to the economic torque is easily perceived by the driver as a result of the change in effort and serves as a benchmark for driving the vehicle. The arsenal of existing technologies for metering and injecting fuel into an internal combustion engine is varied enough to offer solutions adapted to the total injection engine which has just been described. Consider the fuel you choose. The ecological vocation of this engine militates in favor of a fuel highly enriched with vegetable-based alcohols; compared to diesel, such a fuel will have a lower viscosity and calorific value, and conversely a much higher volatility and heat of vaporization. In this case, it may be advantageous to use so-called electronic injection techniques, that is to say with injectors whose movement of the needle is controlled by an electronic processor. The system proposed by the invention is shown diagrammatically in FIG. 12 and comprises two parts: one for pumping, the other for injection.

A rotary positive displacement pump (87), driven by the engine, draws the fuel into a tank (88) through a non-return valve (89) and discharges it into an accumulator (91); the regulation is made by an electro-valve (92), normally open and controlled by pressure. At the start the valve closes and the pump (87) charges the accumulator (91) until the operating pressure is reached; the valve then opens and the pump only delivers on itself; when stopped the accumulator is slowly emptied towards the tank through a small nozzle (90).

The injection part comprises: at least one injector (93) per cylinder and a temperature measurement (94), an electronic processor (95), finally on the circuit connecting the accumulator (91) to the injectors (93) a device for variable throttle (96), controlled by a small stepping motor (97), which can be achieved by a cam whose profile moves in front of a calibrated hole. The basic parameters of the injection are linked at each instant by the relation: 6. NOT . V = S. AT . U in which: _ N is the speed of rotation of the engine in revolutions / minute _ V is the unit volume of fuel to be injected in cm3 _ S is the throttling section of the device (96) in cm2 _ A is the angular duration injection in degrees

U is the speed of the liquid in section S in cm / second

This speed U depends above all on the regulated pressure in the accumulator and can therefore, as a first approximation, be considered to be constant. To modulate V, the processor will act essentially on S, by positioning the motor (97), and on A by the very precise emission of the tops which control the opening and closing of the injectors. Variation total of the second member of the above relation must be able to equal that of the first; for example if the variation ratio of N is 9 and that of V 8, it must be possible to reach 72 with the couple S_A, for example by setting 16 for S and 4.5 for A. From complete bench tests, by exploring the total range of speeds and torques, we know the preferred values to give to S, A as well as in advance to the injection. This "map" of values is placed in the memory of the processor (95) and will serve as references for defining its action. At all times the processor is informed: _ by a magnetic sensor of the position and the speed of the crankshaft _ by a sensor for displacement of the position of the accelerator pedal, therefore of the torque requested by the driver _ finally by the sensors (94) of the exhaust gas temperature.

From these elements the processor instantly calculates the parameters used to drive the engine (97) and the injectors (93); this calculation is done in two stages: first read the values in the ROM then correct them more or less in order to maintain the temperature of the gases (94) in an optimal range; this last point is particularly important; it prevents overheating of the parts most exposed to high temperatures; it allows starting to accelerate the warming up of the engine; finally for all operating conditions it guarantees the best thermodynamic efficiency.

To accelerate the gasification of the jet of liquid fuel and at the same time protect the nozzle nose, a nozzle (98) is placed in front of it and fixed in an orifice (22) of the duct (6). Figure 13 shows the enlarged views of this arrangement. The nozzle (98) has a central core, which ends in a point just in front of the injection orifice, with all around the helical grooves. The fuel flows in thin layers therein in a swirling motion. There is a very efficient transfer of heat from the hot walls to the fuel and most of it is gasified before entering the duct (6).

Claims

1) Piston engine, internal combustion, intended for driving motor vehicles, operating in a two-stroke cycle with injection of both fuel, hydrocarbons and / or alcohols, and of oxidizer, compressed air in an organ separated from the engine and brought to high temperature by the exhaust gases, characterized in that the admission of this air from its source (1) to the cylinder (s) (2) is carried out by means of the elements following:

_an air intake valve (10), normally closed and the opening of which is controlled by the accelerator pedal (11); _ a rotary distributor (15) of frustoconical shape with a duct (18) bringing air through the large face of the cone and at least one injection orifice (19), of this air, disposed at the periphery; a general casing (3) surrounding the distributor (15), with a bore (5) of the same conicity as the latter, and clamped against the top of the cylinders (2) by a plate (4) integrated in the foundry of said casing;

_ for each cylinder (2) a gas transfer duct (6), passing through the plate (4) and opening into the bore (5) through an orifice in the form of a slot, oriented along the generatrix of the cone ; _ a transmission (14) of the distributor (15) by toothed belt, driven by the crankshaft and such that the orifice (19) passes in front of the slot in the conduit (6) when the piston (13) is close to top dead center; a tight rotary connection, supplied with compressed air by the valve (10), with a fixed part (9), integrated at the end of the casing (3), in which the duct (18) can slide and the section of which is fixed so that the pushing force of the air thereon is just sufficient when running to keep the distributor (15) in contact against the conical bore (5).

2) Engine according to claim 1 characterized in that the circuit of the burnt gases leaving the cylinders (2) and their heat transfer to the intake air are produced in the same member integrated into the distributor (15) and the casing ( 3) by means of the following devices: at least one gas ejection orifice (20) disposed at the periphery of the distributor (15) so as to pass in front of the slot in the conduit (6) during the upward stroke of the piston (13 ); a first exchanger (16), of dynamic type, integrated between the distributor (15) and the duct (18), internally traversed by the intake air and externally by the axial flow of gases escaping from the distributor ( 15) the exchange surface being enlarged by external fins (17); _ a second exchanger (8), also against the current but fixed, arranged all around the previous one and recovering the residual heat of the gases before their rejection in the open air; _ a preheating circuit (7), arranged in the hot walls of the casing (3) around the distributor (15), in which fresh compressed air from the source (1) is circulated before it enters the exchanger (8), while lowering the temperature of said walls;

_ a heat-insulating envelope (12) arranged all around the casing (3). 3) Engine according to claims 1 and 2 characterized in that, in its most common version, it is composed of at least one distributor assembly (15,21) attached on one side to a group of two cylinders (2) , arranged in parallel with alternating movement of the pistons (13), and the other to the group of exchangers, this assembly comprising: _ a distribution rotor (15), the conical surface of which has two air injection orifices (19), opposite by the diameter, and similarly two orifices (20) for the exhaust of the burnt gases, rotating at half the speed of the crankshaft with an angular phase shift system, controlled by the accelerator pedal, capable to vary the angle of closure of the intake;

_ a distribution stator (21), made of cast iron, itself having:

_ two symmetrical conduits (6) whose slots opening into the conical bore (5) are offset by 90 degrees;

_ a succession of cooling cells (25) occupying the entire periphery of the bore (5) with the exception of the location of the conduits (6);

_ on the rear face a circular cavity 9) which receives the fresh air by at least one lateral inlet and distributes it in the cells (25); _ on the front face a connection flange;

_ on each side of the plate (4) orifices (22), opening at the end of the conduits (6), and where the combustion control elements are fixed (in ectors, candles, temperature sensors).

4) Engine according to claim 3 characterized in that each cylinder:

_ forms a separate unit, clamped between the motor housing and the plate (4) by means of tie rods (23);

_ consists of a main body (2), made of cast iron, fitted over its entire periphery with longitudinal grooves (30), around which is clamped a steel ferrule (31), welded or crimped at each end; _ is cooled both externally by circulating, from the tubes (32) of the ferrule (31), in the grooves (30) a liquid under, pressure based on demineralized water, and internally by injecting into the center of the cylinder, through an orifice (33) of pressurized oil, previously cooled in an exchanger by ambient air; is embedded in a housing machined in the bottom of the plate (4) by enclosing a wafer (24), made of ceramic material resistant to very high temperatures, drilled in the center of a round hole, slightly flared, arranged in the extension of the conduit ( 6). 5) Engine according to all of claims 1 to 4, characterized in that the pistons are arranged with the following specific provisions: on top of the main body (13), cast in an aluminum alloy, are stacked in the order an elastic flat washer (28), made of stainless steel sheet, a rigid insulating plate (27), finally a cap (26), made of ceramic material resistant to very high temperatures;

_ these three parts (26,27,28) are strongly tightened by a flange (2§) in refractory steel, which is supported on the edges of the cap (26) and carries the upper sealing segments, and whose lower skirt is attached to the body (13) by soldering and / or crimping; _ the body (13) and the collar (29) are directly cooled by a forced circulation of oil under pressure, injected by the orifices (33) of the cylinders, in an annular space arranged around the piston between the upper and lower seals, and driven back by a row of small holes which cross the walls and emerge flush with the vault of the piston; _ the upper profile of the cap (26) fits together with a small clearance in that of the wafer (24) so that the volume at top dead center is practically equal to that of the duct (6) and that when the piston begins its descent a narrow flared annular passage is created between the ceramic pieces (24) and (26). 6) Motor according to all of claims 1 to 3, characterized in that the rotary exchanger comprises the following elements: a bundle of tubes (34), made of refractory steel, fitted in a series of radial washers (35), thin sheet metal, offering a large direct contact surface with the burnt gases; _ connection flanges (36), welded at each end of the bundle (34), and fitted tightly in a circular cavity, on one side against a box (37) which distributes the intake air in the tubes, and on the other against the rotor (15) which distributes this air to the cylinders; _ a shaft (38), preferably in steel and hollow, attached on one side to the rotor (15) and provided on the other with a nut (39) allowing the beam (34) to be tightened between the housing (37 ) and the rotor (15);

_ deflectors (40), ceramic, stacked and centered on the shaft (38), forming a series of circular grooves and having internally only small areas of contact with the shaft (38);

_ partitions (41,42), regularly arranged along the beam (34), and which complete the action of the deflectors (40) by forcing the flow of burnt gases to carry out a succession of back and forth between the center and the periphery by crossing each time the bundle of tubes (34) and licking the washers (35).

7) Motor according to all of claims 1 to 6 characterized in that the fixed exchanger (43,46,47) and the intake valve (50,52), integrated at its end, form an elongated cylindrical member, fully insulated, which completely encloses the rotary exchanger and includes:

_ a main body (43), cast in an alloy which is a good conductor of heat, provided with external longitudinal grooves (44) and internal (45) nested alternately against each other, closing at the end on a bore in which comes '' fitting the body (52) of the valve; _ a cylindrical outer casing (46), made of steel, fixed by a flange on one side to the front face of the stator (21) and on the other to the cylinder body (50) of the valve, fitted tight against the grooves ( 44) by forming canalsa¬ tions in which circulates and heats the air coming from the cells (25); _ a cylindrical inner ferrule (47), made of stainless steel, fitted tightly into the body (43), encircling with a very small clearance the partitions (41) of 1 "rotating exchanger and forcing the gases leaving the latter to circulate, to against the current, in the grooves (45) then to escape into the open air through holes placed at the end of these which pass through the walls of the body (43) and of the envelope (46). 8) Motor according to Claims 1 to 7, characterized in that the cylinder-assisted valve integrated at the end of the fixed exchanger (43, 46), and which controls the admission of air into the housing (37), is produced and operates in the following ways:

__ the cylinder body (50) is provided with a flange which makes it possible to firmly and tightly seal the flat and machined end of the casing (46) against the body (52), the face of which support is provided with studs (53) ensuring both precise centering and air passages; _ the body (52) has a machined cylindrical end on the exchanger side serve as an axis of rotation of the housing (37), with to limit the axial movement of said housing an anti-friction abutment washer (49); the movable equipment of the valve comprises a valve (48), the rod of which, sliding in a guide incorporated in the body (52), is fixed to a piston (51) of the cylinder body (50), the section of this piston being slightly greater than that of the valve (48); when stopped, this valve is applied against its seat, machined inside the aforementioned tubing of the body (52), by venting the chamber of the jack (50); _ the opening of the valve and consequently the starting of the engine is obtained by sending in the aforementioned chamber a pressure either equal to that of the source (1), for an admission without expansion, or to a fraction of this- ci, for a strangled admission.

9) Engine according to all of claims 1 to 8 characterized in that the first turns of the engine, in the right direction, to start starting as soon as the valve opens (48), are obtained by: a fixed diffuser (54 ), integrated into the valve body (52) in the extension of the axis of rotation of the housing (37), which receives in the center the radial air flow produced by the opening of the valve and directs it, thanks to its slats, creating a rotating movement at high speed; a small turbine (55), integrated in the casing foundry (37) at the entrance of the circular cavity which feeds the bundle of tubes (34) and whose blades transform the kinetic energy of the air streams into a torque of rotation, the movement being transmitted by the shaft (38) to the entire mobile engine assembly.

10) Motor according to all of claims 1 to 9 characterized in that the distribution rotor (15) is constructed and arranged as follows: said rotor is cast in an alloy, or formed in a ceramic material, resistant to high temperatures and comprises an internal partition separating the intake air and the exhaust gases;

_ the hot air coming from the bundle (34) first fills the circular cavity (60), then two conduits (59) which open onto the conical wall through the orifices (19), finally a large spherical central cavity (61) , extended at the front by a sheath in which the shaft is fitted (38); _ the burnt gases pass through the passage (58), around the cavity (61) and its sheath, and are ejected axially in the center; the central shaft (38) is welded to a head (62) which bears against the rear face of the rotor, closing the cavity (61), and is extended by a short axis provided with a conical seat and grooves for the rotor drive.

11) Motor according to all of claims 1 to 10 characterized in that 1 * rotor drive (15) is made with the following elements: _ a pulley (56) with toothed belt, itself driven by the crankshaft , rotating in a bearing (64), preferably with ball and oblique contact, Im-Even held in a support (65), fixed to the stator (21) near the air inlet, all these parts (56, 64.65) being largely ventilated by ambient air;

_ a wafer (66), made of insulating ceramic material, riveted on a steel hub (67), itself coupled to the head (62) and sliding on guides (68), parallel to the axis of rotation and integrated to the pulley (56); _ springs (69), preferably fitted on the guides (68), which hold the pulley (56) against its bearing (64) and, when stationary, push back the wafer (66) and the whole assembly rotating against the thrust washer (49) by slightly separating the conical surface of the rotor (15) from that of the bore (5);

_ a plate (63), made of rigid insulating material, fixed on the entire rear face of the stator (21), with a central orifice adjusted to provide a sealed passage to the hub (67). 12) Engine according to claim 3 characterized in that the phase shift device between the crankshaft and the rotor (15), controlled by the accelerator pedal, comprises: a return by couple of helical gears, with perpendicular axis, one (78) fixed at the end of the crankshaft, the other (79) sliding axially, by means of grooves on a shaft (84) at the end of which is fixed a toothed pulley (71) itself driving the pulley (56) of the rotor (15); _ a crankcase (70) made of aluminum, provided with a cover (81) for mounting, attached to the crankcase of the engine at the end of the crankshaft, with a circulation of the oil therefrom to lubricate the preceding members (78, 79.84); _ a pusher (80), sliding in a central bore of the cover (81) exactly in the axis of the shaft (84) and the end of which rests against a rigid ball bearing (82) fixed at the end pinion (79); a spring (83), for the return of the pusher (80), which is supported on one side at the bottom of a central cavity arranged in the shaft (84) and on the other firmly holds the pinion (79) , by its bearing (82), against the cover (81) "

13) Engine according to all of claims 1 to 12 characterized in that the accelerator pedal acts gradually on the air mass compressed, injected at each cycle, thanks to the following arrangements: _ a cable (72), actuated by said pedal, pulls in the middle of an articulated lever (86) which distributes this force on one side on the pusher (80) and on the other on the slide (73) of a compressed air servo-valve whose body, integrated in the casing (70), has a pressurizing chamber (75); the slide (73) slides both in the body of the servo-valve and in a free piston (74) connected on its periphery to the source of compressed air and subjected on the control side to the air pressure of the chamber ( 75) and the other to the opposing force of a spring (76); _ the depression of the drawer (73) in the piston (74) opens a passage of compressed air towards the chamber (75) and its recoil, by the small return spring (77), lets out the air from this same room to the outside; _ the pressure in the chamber (75), which increases with the depression of the slide (73) and the compression of the spring (76), is transmitted by piping to the jack (50) of the inlet valve; the spring is calibrated so that, at the end of its travel, this pressure is equal to that of the source of compressed air; _ the spring (83) is dimensioned so that the depression of the pusher (80) requires a much higher effort than that of the drawer (73) and begins when the latter is at the end of its travel, creating a position of reference, the accelerator pedal, for economical driving of the vehicle;

14) Engine according to all of claims 1 to 13 characterized in that the fuel metering and injection system comprises: _ an accumulator (91) in which the fuel is maintained at a constant pressure by a positive displacement pump (87 ) driven by the engine; _ by cylinder at least one injector (93), electrically controlled by solenoid, and a temperature measurement (94), both fixed in the orifices (22) opening into the duct (6);

_ between the accumulator (91) and the injectors (93) a device (96) creating a variable throttled section by means of a cam, driven by a stepping motor (97), and whose profile s' gradually deviates from a nozzle; an electronic processor (95) which simultaneously controls the engine (97) and the injectors (93) from information transmitted by sensor: speed and position of the crankshaft, position of the accelerator pedal, temperature of the burnt gases; _ a nozzle (97), centered just in front of the outlet of each injector, forcing the fuel jet to divide into multiple layers in helical grooves arranged over the entire periphery of said nozzle.