EP3662153B1 - External heat source engine with slide valves - Google Patents

Description

Technical area

The present invention relates to an external hot source engine.

State of the prior art

External hot source engines, for example of the Ericsson type, are experiencing renewed interest and development, with the aim of reducing pollutant emissions or reducing energy consumption by recovering heat discharges. This type of engine operates between two heat sources external to the engine via exchangers. It uses valves to control the flow of the working fluid (in the gas phase) between two chambers, one for compression and the other for expansion.

For positive displacement machines such as piston internal combustion engines, distributions using valves actuated by cams are also known. This type of distribution has various limitations. In particular, the pressure on the face of the valve opposite the working chamber must be low. In addition, the maximum lift of the valve is low if the duration (measured in degrees of angle of rotation of the cam) of opening of the valve is short. In addition, the cam drive consumes energy.

We also know volumetric machines, such as compressors, which use valve distribution. This solution requires that the pressure differential on each valve always have, at each stage of the machine's operating cycle, an appropriate value and direction so that the valve is in the state - open or closed - necessary at the considered stage of the cycle.

In certain volumetric machines with an external hot source, such as those described in the two patent applications FR 2 905 728 And FR 2,954,799 , the working gas is compressed in a working chamber, then transferred to a hot source, and from there re-transferred into the same working chamber at the start of an expansion period of this chamber. To be effective, the two aforementioned transfers of the working gas must be brief and take place through a passage section large enough to minimize pressure losses. These requirements are difficult to meet with cam-controlled valve timing. Furthermore, this type of cycle is difficult to compatible with distribution by valves. US2006213207 A1 , EP2816013 A2 And US2008148731 A1 disclose external hot source motors.

The aim of the present invention is to propose an external hot source engine making it possible to remedy at least in part the problems cited above. It also aims to offer a space-saving engine.

Presentation of the invention

According to a first aspect of the invention, at least one of the objectives is achieved with an external hot source engine according to claim 1.

According to the invention, the distribution comprises at least one rotary valve mounted in rotation in the cylinder head and comprises internal passages opening through its side wall by at least one mouth which communicates selectively with the working chamber by at least one opening made in the cylinder head.

The engine according to the invention has the advantage, compared to devices comprising valves, of distributing gas flows with little pressure loss, via large passage sections for very short periods of time. Compared to a motor implementing an ERICSSON cycle, the motor according to the invention makes it possible to significantly divide friction and load losses. It makes it possible to improve the efficiency of the engine while reducing the number of parts and thus the size and weight of the engine.

By bushel we mean a cylindrical element comprising internal passages in which the working gas can circulate. An internal passage is for example a conduit. The plug is arranged so that its axis of rotation is perpendicular to the axis of the cylinder above which it is arranged. The plug is located between the working chamber and the exchanger along the working gas path. The rotary movement of the plug is synchronized with the reciprocating movement of the piston, so that the working gas can pass through the plug via the internal passages, and thus distribute the gas between the working chamber and the exchanger. Preferably, each internal passage communicates with at least two openings provided through the side wall of the plug, each opening being located at one of the two ends of the internal passage. At a certain stage of the cycle, the working gas flows between the working chamber and the cold inlet of the exchanger, passing through at least one port of the cylinder head and at least one internal passage of the rotating plug. A mouthpiece is an opening in the plug which selectively coincides with at least one opening made in the breech.

The valve distribution system makes it possible to provide a large section for the passage of the working gas, particularly as soon as a mouth begins to coincide with a port in the cylinder head. As the speed of rotation of the plug is substantially constant, the passage section increases rapidly, for example linearly, until the mouth coincides perfectly with the opening of the cylinder head. On the contrary, by its geometry (substantially ovoid), a cam actuates a valve according to a substantially sinusoidal law so that the passage section of the working gas increases very slowly at the start of the opening movement.

• un gaz de travail, sensiblement froid est admis dans la chambre de travail,
• ledit gaz est comprimé dans ladite chambre de travail, puis
• transféré dans l'échangeur dans lequel un fluide calo-cédant (la source chaude) circule, de façon à chauffer le gaz de travail ;
• le gaz de travail chauffé est re-transféré dans la chambre de travail en début d'un temps d'expansion de la même chambre de travail ; puis
• l'expansion se poursuit et se termine alors que la chambre de travail est isolée de l'échangeur ; et
• le gaz de travail est échappé de la chambre de travail.

The valve distribution makes it possible to carry out the thermodynamic cycle, of the four-stroke type, as follows:

• a substantially cold working gas is admitted into the working chamber,
• said gas is compressed in said working chamber, then
• transferred into the exchanger in which a heat-transfer fluid (the hot source) circulates, so as to heat the working gas;
• the heated working gas is re-transferred into the working chamber at the start of an expansion time of the same working chamber; Then
• the expansion continues and ends while the working chamber is isolated from the exchanger; And
• the working gas is escaped from the working chamber.

Thanks to the plug, the two aforementioned transfers of the working gas are brief and take place through a passage section large enough to minimize pressure losses.

Preferably, at least one port of the cylinder head is capable of communicating with two internal passages of the plug which open through the side wall of the plug via two circumferentially aligned mouths. The angular difference between the two neighboring mouths is between 5 and 15 degrees. These values, like the angular values provided subsequently, concerning the mouths and the orifices, are indicated for a rotation speed of the plug of between 3000 and 4000 rpm (revolutions per minute) and a temperature of the heat transfer fluid of between 500°C and 600°C (degrees Celsius). Said two internal passages are, one, a passage through which the working gas enters the working chamber, and the other, a passage through which the working gas leaves the working chamber. This characteristic allows a working gas leaving the working chamber, and a working gas entering the working chamber, to cross paths. This avoids an unfavorable phenomenon of relatively low pressure in the working chamber at the start of the expansion phase.

• un passage interne destiné à faire circuler le gaz de travail froid et comprimé entre la chambre de travail et l'extrémité froide de l'échangeur, et
• un passage interne, distinct du précédent, destiné à faire circuler le gaz de travail, comprimé et chauffé, entre l'extrémité chaude de l'échangeur et la chambre de travail.

For example, the bushel includes:

• an internal passage intended to circulate the cold and compressed working gas between the working chamber and the cold end of the exchanger, and
• an internal passage, distinct from the previous one, intended to circulate the working gas, compressed and heated, between the hot end of the exchanger and the working chamber.

The working gas entering the exchanger is said to be “cold” in comparison with its higher temperature when it leaves the exchanger “hot”. It must, however, be clearly understood that the “cold” working gas entering the exchanger is already heated by its compression in the working chamber. Likewise, the “cold” end of the exchanger is still at a temperature close to that of the working gas at the end of compression.

Preferably, the distribution is arranged so that, towards the end of compression, the working chamber begins to communicate with the cold end of the exchanger when the pressure in the working chamber is lower than the pressure in the 'exchanger. During operation of the engine and with reference to the cycle described above, the cold and compressed working gas and/or being compressed enters the rotating plug as soon as at least part of the mouth coincides with the light so as to circulate the cold and compressed working gas towards the cold end of the exchanger. The passage section between the working chamber and the mouth increases with the rotation of the bushel. When the mouth of the plug coincides perfectly with the port of the breech, the passage section is maximum. The majority, at least 50%, of the volume of cold and compressed working gas has then passed said mouth. Then, due to the rotation of the plug and the end of the compression, only part of the mouth coincides with the light, so as to circulate the remaining part of the cold and compressed working gas towards the cold end of the exchanger. Simultaneously, the passage section between the working chamber and the second mouth, of the second internal passage, increases so that part of said mouth coincides with the same light. The working gas leaving the second mouth, and therefore entering the working chamber, comes from the hot end of the exchanger after being heated. The working gas thus makes a loop passing through the same port of the cylinder head but through different internal passages of the valve. This makes it possible to make said larger light, and therefore to further increase the passage section offered to the gas to pass into the exchanger and return. For a short time the cold working gas and the hot working gas pass each other.

In one embodiment, at the end opposite the mouths, the internal passages open out through the side wall of the plug through orifices which communicate selectively with fixed connections depending on the angular position of the plug. The plug ports allow working gas to flow from the internal passages of the plug to the fittings or from fittings to the internal passages of the plug.

Preferably, for each internal passage, the geometry of the at least one bushel is such that the orifice is capable of communicating with the corresponding connector when the mouth communicates with the working chamber. This characteristic makes it possible to communicate the working chamber with the connections, so as to circulate the working gas.

Said connections include a cold connection communicating with the cold end of the exchanger and a hot connection communicating with the hot end of the exchanger. Said fittings include an inlet fitting communicating with the working gas inlet and an exhaust fitting communicating with the working gas exhaust.

For the above and for the rest of the application, the terms mouth and orifice correspond to or qualify openings made through the side wall of the plug. The term mouthpiece is used to describe each opening capable of communicating with the port of the breech for the passage of the working gas from the working chamber to the bushel or vice versa. The term orifice is used to describe each opening capable of communicating with a fitting for the passage of working gas from the valve to the fitting or vice versa. A mouthpiece cannot serve as an orifice and vice versa. For this, on the side wall of the at least one bushel, the at least one mouth is offset axially relative to the at least one orifice.

According to one embodiment, the mouths and orifices or openings of the plug are only arranged through the side wall.

According to another embodiment, the mouths and orifices or openings of the plug can be arranged, in part or only, across the two axial faces of the plug.

According to a preferred embodiment, the engine comprises a low pressure valve controlling the selective communication of the working chamber with the intake and the exhaust. The motor includes a high pressure valve controlling the selective communication of the working chamber with the hot and cold ends of the exchanger. This characteristic makes it possible to simplify the construction of the engine by dissociating the so-called “high pressure” flows and the so-called “low pressure” flows and to reduce its size. The bushels may have the same or different diameters. Bushels of identical diameter make it possible to simplify the construction of the engine. This achievement also satisfies the need to provide a relatively large passage section for the gas going to and returning from the exchanger, since the gas is then compressed, the volume which must flow is smaller than at the inlet and at the exhaust. However, a high pressure plug with a diameter greater than the diameter of the low pressure plug makes it possible to further enlarge the passage section of the internal passages, going to the exchanger and returning.

Preferably, the motor comprises two fixed connections, a so-called “high pressure” connection and a so-called “low pressure” connection. The high pressure connection comprises a cold connection communicating with the cold end of the exchanger and a hot connection communicating with the hot end of the exchanger. The low pressure fitting includes an inlet fitting and an exhaust fitting.

According to a preferred embodiment, the thermodynamic cycle is carried out in a single cylinder. The cylinder head, surmounting the working chamber, supports the high pressure plug and the low pressure plug, which are arranged parallel to each other when viewed parallel to the axis of the plug. The cylinder head has a general geometric shape evoking a triangle. It has a lower face and two curvilinear side faces whose upper ends meet.

The cylinder head has two concave and opposite side faces, each face being arranged to receive a cylindrical bushel, by complementarity of shape. In particular, each side face has a section in the form of an arc of a circle substantially coaxial with the axis of the received bushel. The lights are made in the side faces. Preferably, the lights are rectangular in shape to limit pressure losses.

The cylinder head has a substantially flat lower face intended to be in contact with the engine liner. The lower face includes a chamber opening which defines the entrance to a transition cavity and which, during operation of the engine, extends the volume of the working chamber (similar in shape to the shape of the cylinder) seen parallel to the bushel axis. The transition cavity has a substantially triangular shape. Preferably, the piston head has a shape complementary to the shape of the transition cavity, so that the head can enter the transition cavity.

According to the invention, the at least one mouth comprises two mouths for the same internal passage, capable of communicating simultaneously with the working chamber, through two lights. Each mouth can coincide with a light. This characteristic is particularly advantageous with a view to finding a compromise between a large passage section for the flow of the working gas, limiting the pressure loss of said flow and limiting the leaks of working gas between the plug and the cylinder head. This compromise is all the more important for the high pressure valve.

For example in the compression phase of the working gas and during its routing towards the cold end of the exchanger, the gas passes into the two mouths of the high pressure valve passing through the two ports of the cylinder head so that the flow is divided in two to cross the two lights and the two mouths, forming two flow lines. After the two mouths, each flow line circulates in a conduit opening into a common conduit. The internal passage actually has the shape of a Y according to this particular embodiment.

Preferably, the slots and the mouths have a rectangular shape to limit pressure losses.

Preferably, at least one of the mouths is subdivided by at least one mullion. This characteristic makes it possible to support sealing devices, placed on the cylinder head, when the at least one mouth passes in front of a port of the cylinder head. The mullions can be fitted to both the mouths of the low pressure plug and those of the high pressure plug.

For the above and for the rest of the description, by mullion we mean a bar intended to subdivide only the mouth without protruding inside the bushel (without subdividing the internal passage). It extends circumferentially to connect two longitudinal sides of a mouth so as to extend the circumference of the bushel.

According to another embodiment, which may be compatible with the previous embodiment, at least one passage comprises two passages leading in parallel to the same resource, each capable of communicating simultaneously with a respective port of the cylinder head. This characteristic makes it possible to offer a large passage section for the working gas.

For example, during the return of the working gas coming from the hot end of the exchanger, the flow of the working gas is divided into two flow lines, which circulate in two distinct internal passages inside the valve. The two flow lines are divided before entering the two ports of the plug and rejoin after the exit of the two ports of the cylinder head.

Preferably, the shape of the sections and the layout of the internal passages are made to promote the circulation of the working gas in precise directions, for example to promote the suction of the gas, in particular to avoid a compression effect in the bushel. In addition, they are arranged to limit differential pressures along each bushel. This limits the friction between the valve and the cylinder head and thus limits the risk of working gas leaks around the valve.

According to other embodiments, the external hot source engine may comprise several cylinders such as an internal combustion engine. For example, the engine may include at least two cylinders. In this case, it may include all or part of the characteristics described so far. The at least one plug may comprise two orifices aligned circumferentially to communicate selectively with the same connection, and which each communicate with a respective passage associated with a respective one of the cylinders. This characteristic makes it possible to reduce the size of the bushel and therefore the size of the engine.

The orifices are opposed for example by 180 degrees and the internal passages upstream of said orifices are adjoining and have a common wall.

In the case of two or more cylinders, the plug is advantageously the same for all the cylinders which are arranged in line with each other.

Preferably, the engine includes sealing devices to limit gas leaks. The ports are surrounded by sealing devices to close the gap between the peripheral wall of the plug and an adjacent surface of the cylinder head all around each port. The sealing device may comprise bars of a dry friction material, for example graphite. For example, the bars are arranged on the side faces of the cylinder head around the lights.

According to another aspect of the invention, which may be compatible with the first aspect, there is provided a motorization assembly comprising a motor according to one or more of the characteristics stated above and a heat exchanger having a heat-receiving path extending between a cold end and a hot end selectively connected to the working chamber towards the end of a compression phase and towards the beginning of a relaxation phase, respectively. The working gas circulates in the heat-receptor path.

Preferably, the exchanger is of the counter-current type. The heat exchanger comprises a heat-transferring path traveled in one direction by a heat-transferring fluid, a direction which is opposite to the direction of travel of the working gas in the heat-receiving path. The caloreceptor pathway is distinct from the caloreceptor pathway.

According to one embodiment, the heat exchanger comprises a heat-transfer path traveled by the exhaust gases of an internal combustion engine. According to another embodiment, the heat exchanger comprises a heat-transfer path traversed by a fluid heated with solar energy.

Description of the figures and embodiments

• les figures 1a, 1b, 2a, 2b et 2c sont des représentations schématiques d'un moteur à source chaude externe, comprenant deux boisseaux rotatifs selon l'invention, le moteur étant couplé avec un échangeur de chaleur, l'ensemble moteur et échangeur étant vu en coupe lors des principales phases de fonctionnement du moteur : la figure 1a illustrant une phase d'admission d'un gaz de travail dans le cylindre du moteur, la figure 1b illustrant une phase d'échappement du gaz hors dudit cylindre, la figure 2a illustrant une phase de fin de compression du gaz de travail et au cours de laquelle le gaz est également dirigé vers une extrémité froide de l'échangeur de chaleur, la figure 2b illustrant une phase dans laquelle un boisseau présente une position dite « de balayage » qui autorise la communication fluidique simultanée de l'extrémité froide et l'extrémité chaude de l'échangeur avec le cylindre du moteur, la figure 2c illustrant une phase de détente du gaz de travail après son passage dans l'échangeur ;
• la figure 3 est une vue de dessous et en perspective d'une culasse, selon un mode de réalisation, prévue pour un moteur comprenant deux cylindres, la culasse présentant quatre lumières pour chaque cylindre ;
• la figure 4 est une vue en perspective éclatée d'une partie haute d'un moteur, selon un mode de réalisation comprenant deux cylindres, la partie haute comprenant une culasse, conforme à la figure 3, portant d'une part un boisseau dit « basse pression » recouvert d'un raccord, et d'autre part un boisseau dit « haute pression » qui est vu en éclaté entre la culasse et un raccord prévu pour recouvrir le boisseau haute pression ;
• les figures 5a, 5b, 6a et 6b sont des vues montrant la position angulaire des boisseaux avant et après la phase illustrée par la figure 2b, les figures 5a et 6a illustrant en particulier le boisseau haute pression, selon un mode de représentation similaire à celui de la figure 4, les figures 5b et 6b étant des vues en coupe d'un moteur entier, les figures 5a et 5b illustrant la position angulaire du boisseau haute pression juste avant la position de balayage et les figures 6a et 6b illustrant la position angulaire du boisseau haute pression juste après la position de balayage ;
• les figures 7a et 7b sont des vues montrant la position angulaire des boisseaux lors de la phase d'admission du gaz de travail illustrée par la figure 1a, la figure 7a est une vue en perspective d'une partie haute d'un moteur, selon un mode de réalisation comprenant deux cylindres, la partie haute comprenant une culasse portant d'une part un boisseau haute pression recouvert d'un raccord, et d'autre part un boisseau basse pression qui est vu en éclaté entre la culasse et un raccord prévu pour recouvrir le boisseau basse pression, la figure 7a illustrant en particulier l'orientation du boisseau basse pression selon son axe de rotation, la figure 7b étant une vue en coupe d'un moteur entier ;
• les figures 8a et 8b sont des vues montrant la position angulaire des boisseaux lors de la phase d'échappement du gaz de travail illustrée par la figure 1b, la figure 8a est une vue en perspective conforme à la figure 7a et illustrant l'orientation du boisseau basse pression selon son axe de rotation, la figure 8b étant une vue en coupe d'un moteur entier.

Other advantages and particularities of the invention will appear on reading the detailed description of implementations and embodiments in no way limiting, and the following appended drawings:

• THE figures 1a, 1b, 2a, 2b and 2c are schematic representations of an external hot source engine, comprising two rotating bushels according to the invention, the engine being coupled with a heat exchanger, the engine and exchanger assembly being seen in section during the main operating phases of the engine : there figure 1a illustrating a phase of admission of a working gas into the cylinder of the engine, the figure 1b illustrating a phase of escape of the gas from said cylinder, the figure 2a illustrating a phase at the end of compression of the working gas and during which the gas is also directed towards a cold end of the heat exchanger, the figure 2b illustrating a phase in which a plug has a so-called “scanning” position which allows simultaneous fluidic communication of the cold end and the hot end of the exchanger with the engine cylinder, the figure 2c illustrating an expansion phase of the working gas after its passage through the exchanger;
• there Figure 3 is a bottom perspective view of a cylinder head, according to one embodiment, provided for an engine comprising two cylinders, the cylinder head having four ports for each cylinder;
• there Figure 4 is an exploded perspective view of an upper part of an engine, according to an embodiment comprising two cylinders, the upper part comprising a cylinder head, conforming to the Figure 3 , carrying on the one hand a so-called “low pressure” valve covered with a fitting, and on the other hand a so-called “high pressure” valve which is seen exploded between the cylinder head and a fitting designed to cover the high pressure valve;
• THE figures 5a, 5b , 6a and 6b are views showing the angular position of the bushels before and after the phase illustrated by the figure 2b , THE figures 5a And 6a illustrating in particular the high pressure valve, according to a mode of representation similar to that of the Figure 4 , THE figures 5b And 6b being sectional views of an entire engine, the figures 5a and 5b illustrating the angular position of the high pressure valve just before the sweep position and the figures 6a and 6b illustrating the angular position of the high pressure valve just after the sweep position;
• THE figures 7a and 7b are views showing the angular position of the bushels during the working gas admission phase illustrated by the figure 1a , there figure 7a is a perspective view of an upper part of an engine, according to an embodiment comprising two cylinders, the upper part comprising a cylinder head carrying on the one hand a high pressure valve covered with a fitting, and on the other hand a low pressure valve which is seen exploded between the cylinder head and a connection provided to cover the low pressure valve, the figure 7a illustrating in particular the orientation of the low pressure valve along its axis of rotation, the figure 7b being a sectional view of an entire engine;
• THE figures 8a and 8b are views showing the angular position of the bushels during the exhaust phase of the working gas illustrated by the figure 1b , there figure 8a is a perspective view conforming to the figure 7a and illustrating the orientation of the low pressure valve along its axis of rotation, the figure 8b being a cutaway view of an entire engine.

These embodiments being in no way limiting, we can in particular consider variants of the invention comprising only one selection of characteristics described subsequently isolated from the other characteristics described (even if this selection is isolated within a sentence including these other characteristics), if this selection of characteristics is sufficient to confer a technical advantage or to differentiate the invention by compared to the state of the prior art. This selection includes at least one preferably functional characteristic without structural details, and/or with only part of the structural details if this part only is sufficient to confer a technical advantage or to differentiate the invention from the state of the art. anterior.

• un bloc-moteur dans lequel est formée une cavité cylindrique appelée cylindre 2,
• un piston mobile 3 agencé pour se déplacer en va et vient dans le cylindre 2,
• une culasse 4 coiffant le bloc-moteur au-dessus du cylindre 2, une chambre de travail 5 étant délimitée pour un gaz de travail, typiquement de l'air, dans le cylindre 2 entre le piston 3 et la culasse 4,
• une distribution montée dans la culasse 4, agencée et configurée pour faire communiquer sélectivement la chambre de travail 5 avec les ressources suivantes :
  • ∘ une admission A de gaz de travail,
  • ∘ une extrémité froide B d'un échangeur de chaleur,
  • ∘ une extrémité chaude C de l'échangeur de chaleur,
  • ∘ un échappement D.

THE figures 1a, 1b, 2a, 2b and 2c illustrate the main operating phases of an external hot source engine 1, and will make it possible to describe the engine, according to an embodiment including the essential characteristics. The engine includes:

• an engine block in which a cylindrical cavity called cylinder 2 is formed,
• a movable piston 3 arranged to move back and forth in the cylinder 2,
• a cylinder head 4 covering the engine block above the cylinder 2, a working chamber 5 being delimited for a working gas, typically air, in the cylinder 2 between the piston 3 and the cylinder head 4,
• a distribution mounted in the cylinder head 4, arranged and configured to selectively communicate the working chamber 5 with the following resources:
  • ∘ a working gas admission A,
  • ∘ a cold end B of a heat exchanger,
  • ∘ a hot end C of the heat exchanger,
  • ∘ an exhaust D.

The engine is connected to a heat exchanger 6 for heat exchange between the working gas, called heat-receiving fluid, and a heat-transferring fluid. The heat exchanger 6 is of the counter-current type. It includes a heat-yield path 61 traversed by the heat-yield fluid from the left to the right. It further comprises a heat-receiving path 62, represented under the heat-giving path 61, with reference to the figures 1a to 2c , so that the working gas travels the heat-receptor path from right to left. The caloreceptor pathway is distinct from the caloreceptor pathway. The heat transfer fluid is, for example, the exhaust gases of an internal combustion engine.

The heat exchanger 6 is connected to the engine via fittings and pipes so as to be able to circulate the working gas from the engine to the exchanger and vice versa. Likewise, one or more fittings or pipes are connected to the engine to provide intake and exhaust.

The distribution comprises two rotating bushels 20, 30 mounted in rotation in the cylinder head 4, above the working chamber 5. The axes of rotation of the two bushels are parallel to each other and orthogonal to the axis of the cylinder 2. The bushels comprise a so-called “low pressure” bushel 30 arranged and configured to control the selective communication of the working chamber 5 with the inlet A and the exhaust D. The bushels include a so-called “high pressure” bushel 20 arranged and configured to control the selective communication of the working chamber 5 with the hot C and cold B ends of the exchanger 6. Preferably, the high pressure valve 20 is used only to control the circulation of the working gas between the chamber work and the exchanger. Likewise, the low pressure valve is used only to control the intake and exhaust. This characteristic makes it possible to simplify the construction of the engine by dissociating the so-called “high pressure” flows and the so-called “low pressure” flows and to reduce its size. The bushels have identical diameters to simplify the construction of the engine.

Each bushel 20, 30 includes internal passages for conducting the working gas between the working chamber 5 and the resources. Each internal passage has two ends which open through the side wall of a bushel each through at least one opening. The distribution is arranged and configured so that the rotary movements bushels are synchronized with the reciprocating movement of the piston, so that the working gas can pass through the bushels via the internal passages. The openings are arranged and configured to selectively coincide with at least one port made in the cylinder head and at least one port made in a fixed connection. The mouth is the opening facing the port of the breech during the passage of the working gas between the working chamber and the plug or vice versa. The opening opposite a fitting during the passage of the working gas between the plug and said fitting or vice versa is called an orifice. A mouthpiece cannot serve as an orifice and vice versa. For this, the orifices have an axial offset with the mouths.

• pour l'admission A, un passage interne comprenant une embouchure d'admission et un orifice d'admission,
• pour l'échappement D, un passage interne comprenant une embouchure d'échappement et un orifice d'échappement, et

le boisseau haute pression comprend :

• pour le transfert du gaz de travail depuis la chambre de travail 5 vers l'extrémité froide B de l'échangeur 6, un passage interne comprenant au moins une embouchure froide et au moins un orifice froid,
• pour le transfert du gaz de travail depuis l'extrémité chaude C de l'échangeur 6 vers la chambre de travail 5, un passage interne comprenant au moins une embouchure chaude et au moins un orifice chaud.

According to one embodiment, which goes beyond the text of the claims, of an engine comprising a single cylinder, the low pressure valve comprises:

• for intake A, an internal passage comprising an intake mouth and an intake orifice,
• for the exhaust D, an internal passage comprising an exhaust mouth and an exhaust port, and

the high pressure valve includes:

• for the transfer of the working gas from the working chamber 5 to the cold end B of the exchanger 6, an internal passage comprising at least one cold mouth and at least one cold orifice,
• for the transfer of the working gas from the hot end C of the exchanger 6 to the working chamber 5, an internal passage comprising at least one hot mouth and at least one hot orifice.

The plug distribution makes it possible to carry out the thermodynamic cycle, the main phases of which will now be described.

In reference to the figure 1a , the phase of admission of a working gas into the working chamber 5 is illustrated. The synchronization of the piston 3 and the plugs 20, 30 is such that the movement of the piston 3 is downward while the rotation of the plug is low. pressure 30 allows an inlet mouth 32 of the low pressure valve to communicate with a port of the cylinder head and simultaneously allows an intake port 34 to communicate with a port of an intake fitting. The working gas passes through the internal passage between the inlet port and the inlet mouth so as to be admitted into the working chamber 5. Simultaneously, no mouth of the high pressure valve communicates with a port of the cylinder head . The working gas is preferably air taken from the external environment. When the piston has reached bottom dead center, the low pressure valve 30 has pivoted so that the inlet mouth 32 of the low pressure valve no longer communicates, even partially, with a port in the cylinder head (excluding possible closing delay). admission).

Then the piston rises so that the trapped working gas is compressed in the working chamber. In reference to the figure 2a , a phase of end compression of the working gas is illustrated. The synchronization of the piston 3 and the valves 20, 30 is such that the movement of the piston 3 is upward while the rotation of the high pressure valve 20 allows a cold mouth 21 of the high pressure valve to communicate with a port in the cylinder head and simultaneously allows a cold orifice 23 to communicate with a port of a connection of the cold end B of the exchanger 6. The working gas passes through the internal passage between the cold mouth and the cold orifice so as to be transferred towards exchanger 6 to be heated. At the same time, no mouth of the low pressure valve communicates with a port in the cylinder head. The synchronization of the high pressure valve relative to the rise of the piston during compression is adjusted so as to limit an unfavorable phenomenon of relatively high pressure in the working chamber.

In reference to the figure 2b , the synchronization of the piston 3 and the valves 20, 30 is such that the piston 3 is located at top dead center while the rotation of the high pressure valve 20 allows a double circulation of working gas inside the latter. The cold mouth 21 of the high pressure valve 20 coincides at least partially with the same port of the cylinder head as previously, and simultaneously the cold orifice 23 coincides at least partially with the same port of a connection of the cold end B of exchanger 6, as previously. A so-called cold internal passage of the high pressure valve allows the working gas to be transferred from the working chamber to the exchanger 6, via the cold end B. In addition, the synchronization allows a hot mouth 22 to coincide at least partially with the same light as for the cold mouth 21, and simultaneously allows to a hot orifice 24 to coincide at least partially with a port of a connection of the hot end C of the exchanger 6. A so-called hot internal passage, distinct from the cold internal passage, allows the working gas to be transferred from the exchanger 6, via the hot end C, towards the working chamber 5.

Communication between the cold end B and the hot end C of the exchanger is then established so that part of the incoming working gas and part of the outgoing working gas come into contact. Working gas still passes through the internal passage between the cold mouth and the cold port, and working gas passes through the internal passage between the hot port and the hot mouth. The volume of previously compressed gas is in fact distributed in the path between the cold end B and the hot end C of the exchanger 6, the working gas being heated thanks to the heat transfer fluid present in the heat-yield path 61 of the exchanger 6. Simultaneously, no mouth of the low pressure valve communicates with a port of the cylinder head.

Afterwards, the heated working gas leaving the high pressure valve expands in the working chamber. In reference to the figure 2c , the synchronization of the piston 3 and the valves 20, 30 is such that the movement of the piston 3 is downward while the rotation of the high pressure valve 20 allows the hot mouth 22 of the high pressure valve to communicate with the same light of the cylinder head as previously and simultaneously allows a hot orifice 24 to communicate with the same port, as previously, of a connection of the hot end C of the exchanger 6. The working gas passes through the internal passage between the hot orifice 24 and the hot mouth 22 so as to be transferred from the exchanger 6 to the working chamber to be relaxed. At the same time, no mouth of the low pressure valve communicates with a port in the cylinder head. Once the piston has reached bottom dead center, no mouth of the high pressure valve communicates with any port in the cylinder head.

In reference to the figure 1b , an exhaust phase of the working gas is illustrated. The synchronization of the piston 3 and the valves 20, 30 is such that the movement of the piston 3 is upward while the rotation of the low pressure valve 30 allows an exhaust mouth 31 of the low pressure valve to communicate with a port in the cylinder head and simultaneously allows an exhaust port 33 to communicate with a port of an exhaust fitting. The working gas passes through the internal passage between the exhaust mouth 31 and the exhaust port 33 so as to be expelled from the working chamber 5. Simultaneously, no mouth of the high pressure valve communicates with a port of the cylinder head. The working gas is released into the external environment. When the piston has reached top dead center, the low pressure valve has pivoted so that the exhaust mouth 31 of the low pressure valve no longer communicates, even partially, with a port in the cylinder head (excluding any possible delay in intake closure). ).

Preferably, the exhaust connection and the intake connection form a single part comprising at least one inlet for the intake and at least one outlet for the exhaust, each of the resources being transferred into a respective conduit. For the following, we can call an exhaust connection and/or an inlet connection indifferently as a so-called “low pressure” connection.

Thanks to the plug, transfers of the working gas are brief and take place through a passage section large enough to minimize pressure losses. Furthermore, as the thermodynamic cycle can be carried out in a single cylinder, the engine has a very small footprint compared to the external hot source engine of the prior art.

We will now describe a specific embodiment, which will be described in these differences with the above embodiment. According to one embodiment, an external hot source engine comprising two cylinders is provided.

In reference to the Figure 3 , there is shown a cylinder head 4 arranged and configured to be installed on an external hot source engine comprising two cylinders arranged in a so-called “in-line” arrangement.

The cylinder head 4 is then provided to overcome an engine block in which two cylinders are formed. It has a lower face 46 and two side faces (not visible on the Figure 3 ) designed to support respectively the high pressure plug and the low pressure plug, which are arranged parallel to each other.

The lower face 46 is substantially flat and is intended to be in contact with the engine jacket. It comprises two chamber openings 46a, 46b, each chamber opening being designed to coincide with a cylinder of the engine. Each chamber opening 46a, 46b defines an entrance for a transition cavity 45 dug inside the cylinder head. The transition cavity 45 has a substantially triangular shape and is, in operation, facing the working chamber. Preferably, the piston head has a shape complementary to the shape of the transition cavity, so that the head can enter the transition cavity. During engine operation, the volume of the cavity extends the volume of the working chamber.

According to the embodiment represented by the Figure 3 , the cylinder head includes eight ports, four ports being provided per cylinder (four on the left part and four on the right part of the Figure 3 ) to circulate the working gas according to the operating phases described above.

For a cylinder, two so-called “high pressure” 41hp lights are provided to circulate the gas towards the high pressure valve and vice versa, and two so-called “low pressure” 41bp lights are provided to circulate the working gas towards the low pressure valve and vice versa. The 41hp high pressure lights are made on the same first side face of the cylinder head. The 41bp low pressure ports are made on the same side face of the cylinder head opposite the first face; the four lights opening into a transition cavity.

In reference to the Figure 4 , there is shown a high engine arranged and configured to be installed on a jacket of an engine with an external hot source comprising two cylinders arranged in a so-called “in” arrangement. line ". The high engine includes a cylinder head 4, conforming to the Figure 3 , on which is mounted a low pressure valve 30 of which only one end is visible on the Figure 4 . The low pressure valve is covered with a low pressure fitting 70 which will be described in more detail below. The cylinder head 4 has on one side face a receiving surface 40 on which a rotating plug, here the high pressure plug 20, can be received. The receiving surface 40 has a concave shape, so as to cooperate by complementarity of shape with the high pressure plug 20. In particular the receiving surface has a section in the shape of an arc of a circle substantially coaxial with the axis of the received plug . The arrangement of the cylinder head 4 is substantially symmetrical with regard to the shape of the side faces. The high pressure valve like the low pressure valve has, in a cross section, a circular exterior shape. In addition, the two bushels have a substantially identical diameter.

According to the embodiment represented by the Figure 4 , the receiving surface 40 comprises four high pressure lights 41hp: two pairs of adjacent lights 41a, 41b, each pair being designed to cooperate with a cylinder. Preferably, the lights have a rectangular shape to limit pressure losses during the circulation of the working gas flow.

• pour l'un des cylindres, dit « cylindre a », le gaz de travail subit une phase de compression, et
• pour l'autre cylindre, dit « cylindre b », le gaz de travail subit une phase de détente.

There Figure 4 shows the high pressure valve in a particular angular position when the engine synchronization is such that:

• for one of the cylinders, called “cylinder a”, the working gas undergoes a compression phase, and
• for the other cylinder, called “cylinder b”, the working gas undergoes an expansion phase.

In this particular position, no working gas circulates in the internal passages of the high pressure valve 20.

With reference to figures 4 , 5a , 6a , the cylinder head 4 comprises two ports 41a provided to overcome cylinder a, and two ports 41b provided to overcome cylinder b. The high pressure valve 20 comprises two adjacent cold outlets 21a, of identical dimensions and aligned on the periphery of the valve, along a direction parallel to the axis of rotation of the bushel. The cold nozzles have a substantially rectangular shape whose longitudinal dimension extends in a direction which is parallel to the axis of rotation of the plug. The cold openings 21a are intended to coincide with the ports 41a of the cylinder head so that the working gas can circulate from the working chamber of the cylinder a towards the high pressure plug 20. At the other end of the internal passage and in reference to the figure 4 , there is a cold orifice 23a arranged at the periphery of the high pressure valve. The two cold mouths 21a on the one hand, and the cold orifice 23a on the other hand, respectively define the two ends of the internal passage used to circulate the working gas towards the cold end of the exchanger. The orifice 23a is intended to coincide with a port 63a of the high pressure connection 60. The orifice 23a has a rectangular shape whose longitudinal dimension extends in a direction which is orthogonal to the axis of rotation of the plug.

In addition, the ports 41 are spaced from one another so that the orifices (cold and hot) face the receiving surface 40 of the cylinder head 4 between two ports. Preferably, the spacing between two transverse edges of two adjacent slots is equal to or greater than the transverse dimension of an orifice. The orifices are therefore sized according to the spacing between two slots, or the spacing between one slot and the axial end of the receiving surface. Thus, for example, the cold orifice 23a is aligned circumferentially with the circumferential surface separating the two cold orifices 21a.

In reference to the Figure 4 , we can also distinguish that the high pressure plug comprises two adjacent hot mouths 22a, of identical dimensions and aligned on the periphery of the plug, along a direction parallel to the axis of rotation of the plug. The hot nozzles have a substantially rectangular shape whose longitudinal dimension extends in a direction which is parallel to the axis of rotation of the plug. The hot mouths 22a are circumferentially aligned with the cold mouths 21a. The hot mouths 22a are intended to coincide with the lights 41a of the cylinder head so that the working gas can flow from the high pressure valve 20 to the working chamber of the cylinder a. Furthermore, the hot mouths 22a and the cold mouths 21a are spaced apart along the circumference of the plug by a very small angular clearance, for example 5 to 15 degrees. The angular movement is chosen so that a light 41 can communicate simultaneously with a cold mouth and a hot mouth.

For example, each hot mouthpiece has, along the circumference of the plug, an angular opening of between 20 and 50 degrees, preferably between 25 and 35 degrees. Given that the engine carries out four main phases and that the internal passages are separated by walls of non-zero thickness, these values are chosen according to a compromise between the need for a large passage section of the working gas flow, reduction of pressure losses and bulk (diameter and length of the bushel). Each cold mouthpiece has, along the circumference of the plug, an angular opening of, for example, between 10 and 40 degrees, preferably between 20 and 30 degrees.

Furthermore, each light 41hp has, along the circumference of the receiving surface 40, an angular opening of, for example, between 15 and 30 degrees.

Preferably, the orifices have, along the circumference of the plug, an angular opening of between 100 and 350 degrees, preferably between 120 and 150 degrees.

Concerning cylinder b and depending on the particular angular position of the high pressure valve, the synchronization of the engine is such that no mouth communicates with the ports 41b of the cylinder head. In reference to the Figure 4 , it can be seen in part that the high pressure valve comprises a cold orifice 23b intended to coincide with a port 63b of the high pressure connection 60 so that the working gas coming from the working chamber of the cylinder b can circulate from the high pressure valve towards the high pressure connection. It can also be seen that the high pressure valve comprises two hot orifices 24b intended to communicate respectively with two ports of the high pressure connection 60 so that the working gas coming from the hot end of the exchanger can circulate from the high pressure connection (via two ports including a port 65 and another non-visible port) towards the high pressure plug destined for the working chamber of cylinder b. The high pressure connection 60 has a covering surface 69 arranged and configured to cooperate by complementarity of shape with the peripheral surface left free by the cylinder head 4. The covering surface 69 has, in a cross section, a shape substantially in the form of an arc of a circle .

Between the part of the high pressure valve selectively communicating with cylinder a and the part of the high pressure valve communicating selectively with cylinder b, the mouths and orifices are respectively diametrically opposed.

• pour le cylindre a, le gaz de travail subit une phase d'échappement, qui sera décrit ci-dessous, et
• pour le cylindre b, le gaz de travail comprimé et/ou en cours de compression est transféré vers l'extrémité froide de l'échangeur (également visible sur la figure 5b).

We will now describe with reference to the figures 5a, 5b , 6a and 6b the angular positions of the high pressure valve 20 when the working gas circulates between the working chamber of cylinder b and the exchanger. There figure 5a shows the high pressure valve in a particular angular position when the engine synchronization is such that:

• for cylinder a, the working gas undergoes an exhaust phase, which will be described below, and
• for cylinder b, the compressed and/or compressed working gas is transferred to the cold end of the exchanger (also visible on the figure 5b ).

With reference to figure 5a , the high pressure plug 20 comprises two cold mouths 21b seen in transparency of the circumference of the plug and conforming to the cold mouths of the Figure 4 . The two cold mouths 21b form the entrance to the internal passage, also seen in transparency, up to a cold orifice 23b. Said internal passage comprises two conduits extending respectively from a cold mouth 21b, then the two conduits join towards a common conduit, thus forming the internal passage between the two cold mouths 21b and the cold orifice 23b. The synchronization of the engine is such that the cold outlets 21b communicate with the lights 41b of the cylinder head so that the working gas circulates from the working chamber of the cylinder b towards the high pressure valve, and simultaneously the cold port 23b, conforming to the cold port of the Figure 4 , communicates with the light 63b of the high pressure connector 60 so that the working gas circulates from the high pressure valve to the high pressure connector. In reference to the figure 5b , the cold mouth 21b coincides perfectly with the port 41b of the cylinder head, and the cold port 23b coincides perfectly with the port 63b of the high pressure connection. The gas, which has been previously compressed in the working chamber by the rise of the piston 3, is pushed back into the internal passage of the high pressure valve 20.

In addition, we can also partly distinguish two hot orifices 24a intended to communicate respectively with two ports of the high pressure connection 60 so that the working gas coming from the hot end of the exchanger can circulate from the high pressure connection ( via two lights, a light 64a and a light 65) towards the high pressure valve 20 destined for the working chamber of the cylinder a.

• pour le cylindre a, le gaz de travail subit une phase de fin d'échappement, qui sera décrit ci-dessous, et
• pour le cylindre b, le gaz de travail sort de l'extrémité chaude de l'échangeur et est transféré vers la chambre de travail du cylindre b pour être détendu (également visible sur la figure 6b).

With reference to figures 6a and 6b , the angular position of the high pressure valve is such that said valve has rotated a few degrees counterclockwise, so that the working gas circulates from the hot end of the exchanger towards the combustion chamber. cylinder work b. There figure 6a shows the high pressure valve in a particular angular position when the engine synchronization is such that:

• for cylinder a, the working gas undergoes an end of exhaust phase, which will be described below, and
• for cylinder b, the working gas leaves the hot end of the exchanger and is transferred to the working chamber of cylinder b to be expanded (also visible on the figure 6b ).

With reference to figure 6a , the high pressure valve 20 comprises two hot orifices 24b conforming to the orifices of the Figure 4 . Each hot orifice 24b forms an entrance to an internal passage, seen transparently from the circumference of the plug, to a hot mouth 22b, the two hot mouths also being seen transparently from the periphery of the plug. Each internal passage leads in parallel the working gas and communicates respectively and simultaneously with a port of the cylinder head. The working gas flow is divided into two flow lines which flow through two separate internal passages within the plug. The two flow lines are divided before entering the two orifices 24b of the high pressure valve and rejoin after the exit of the two ports 41b of the cylinder head. This characteristic makes it possible to offer a large working gas flow passage section.

The synchronization of the motor is such that the hot orifices 24b communicate with lights (the light 65 and a second non-visible light) of the high pressure connection 60 so that the working gas circulates from the hot end of the exchanger towards the high pressure valve 20, and simultaneously the hot mouths 22b, conforming to the hot mouths of the figure 4 , communicate with the ports 41b of the cylinder head so that the working gas circulates from the high pressure valve towards the working chamber of the cylinder b. In reference to the figure 6b , the hot mouth 22b coincides perfectly with the port 41b of the cylinder head, and the hot orifice 24b coincides perfectly with the port 65 of the high pressure connection 60. The gas, which has been previously heated in the exchanger, is expanded in the working chamber of cylinder b so as to push piston 3 in a downward movement.

During operation of the engine and with reference to the cycle described above, the cold and compressed working gas and/or being compressed enters the rotating high pressure valve 20 as soon as at least part of the two cold outlets 21b communicates with the lights 41b so as to circulate the cold and compressed working gas towards the cold end of the exchanger. The passage section between the working chamber and the cold outlets increases with the rotation of the high pressure valve. When the cold mouths of the high pressure valve coincide perfectly with the openings of the cylinder head, the passage section is maximum. Most of the volume of cold and compressed working gas passed through said mouths. Then, due to the rotation of the high pressure valve and the end of compression, only part of the mouthpieces communicate with the ports, so to circulate the remaining part of the cold and compressed working gas towards the cold end of the exchanger. Simultaneously, the passage section between the working chamber and the hot mouths increases so that a part of said hot mouths communicates with the same light. The working gas leaving the hot mouths, and therefore entering the working chamber, comes from the hot end of the exchanger after having been heated. The working gas thus makes a loop passing through the same openings in the cylinder head but through different internal passages of the high pressure valve. For a short time the cold working gas and the hot working gas pass each other.

According to a particular embodiment of the high pressure valve provided for an engine comprising two cylinders, the high pressure valve 20 comprises two orifices aligned circumferentially to communicate selectively with the high pressure connection. In reference to the figure 5a , one of the hot orifices 24a, intended to achieve communication of the working gas coming from cylinder a, and one of the hot orifices 24b, intended to achieve communication of the working gas coming from cylinder b, are aligned circumferentially. Said orifices are arranged substantially in the center of the bushel and are opposed by 180 degrees. The internal passages upstream of said orifices are adjoining and have a common wall. During operation of the engine, each of said two orifices successively communicates a passage associated with a port 65 of the high pressure connection. This characteristic makes it possible to reduce the size of the bushel and therefore the size of the engine.

We will now describe with reference to the figures 7a, 7b , 8a and 8b the angular positions of the low pressure valve 30 when the working gas circulates between the working chamber of one of the cylinders and a low pressure connection 70.

With reference to figures 7a And 8a , there is shown a high engine similar to the figures 4 , 5a and 5b . Only the low pressure part of the upper engine will be described since the high pressure part of the upper engine is identical to the figures 4 , 5a and 5b . As for the high pressure part, the side face housing the low pressure valve has a surface of reception 40 comprising four low pressure lights 41bp: two pairs of adjacent lights 41a, 41b being designed to cooperate respectively with a cylinder a and a cylinder b.

• pour le cylindre a, du gaz de travail est admis dans la chambre de travail (phase d'admission), et
• pour le cylindre b, le gaz de travail subit une phase de détente.

There figure 7a shows the low pressure valve in a particular angular position when the engine synchronization is such that:

• for cylinder a, working gas is admitted into the working chamber (admission phase), and
• for cylinder b, the working gas undergoes an expansion phase.

In this particular position, no working gas circulates in the internal passages of the high pressure valve.

With reference to figures 7a , 8a , the cylinder head 4 comprises ports 41a provided to overcome cylinder a, and ports 41b provided to overcome cylinder b. The low pressure valve 30 includes two adjacent inlet mouths 32a (not visible on the figures 7a ), of identical dimensions and aligned on the periphery of the bushel, along a direction parallel to the axis of rotation of the bushel. The intake mouths 32a have a substantially rectangular shape whose longitudinal dimension extends in a direction which is parallel to the axis of rotation of the plug. According to the angular position represented by the figure 7a , the inlet mouths 32a communicate with the two ports 41a of the cylinder head 4 so that the working gas circulates from the low pressure valve 30 towards the working chamber of the cylinder a. At the other end of the internal passage and with reference to the figures 7a and 7b , there is an inlet orifice 34a arranged at the periphery of the low pressure valve (partially visible on the figure 8a ). The two inlet mouths 32a on the one hand, and the inlet port 34a on the other hand, respectively define the two ends of the internal passage used to circulate the working gas from the low pressure connection 70 towards the chamber working cylinder a. According to the angular position shown, the inlet orifice 34a communicates with an inlet port 74a of the low pressure connection 70.

During operation, the outside air, serving as working gas, is introduced into the low pressure connection via an intake inlet 71. The intake port 34a has a rectangular shape whose longitudinal dimension extends in a direction which is orthogonal to the axis of rotation of the bushel.

In reference to the figure 7b , an inlet mouth 32a coincides perfectly with a port 41a of the cylinder head, and the inlet orifice 34a coincides perfectly with the port 74a of the low pressure connection 70. The downward movement of the piston 3 allows the admission of the gas from work, see arrow fA.

Furthermore with reference to figures 7a And 8a , each pair of lights 41bp is spaced from an axial end 49 of the receiving surface 40 so that the inlet orifices face the receiving surface 40 of the cylinder head 4 between an axial end 49 of the receiving surface 40 and a transverse edge 39 of a slot 41bp of the cylinder head. Preferably, the spacing between an axial end 49 of the receiving surface 40 and a transverse edge 39 is equal to or greater than the transverse dimension of an inlet orifice.

In reference to the figure 7a And 8a , we can also distinguish that the low pressure valve 30 comprises two adjacent exhaust mouths 31a, of identical dimensions and aligned on the periphery of the valve, along a direction parallel to the axis of rotation of the valve. The exhaust mouths 31a have a substantially rectangular shape whose longitudinal dimension extends in a direction which is parallel to the axis of rotation of the plug. Exhaust ports 31a are circumferentially aligned with intake ports 32a. The exhaust ports 31a are intended to communicate with the ports 41a of the cylinder head so that the working gas can circulate from the working chamber of the cylinder a to the low pressure valve 30 via an internal passage. At the opposite end of the exhaust ports 31a, the internal passage opens through an exhaust port 33a. Furthermore, the exhaust mouths 31a and the intake mouths 32a are spaced apart along the circumference of the plug by a small angular clearance, for example, from 100 to 350 degrees, preferably from 200 to 250 degrees.

Preferably, each exhaust mouth has, along the circumference of the low pressure valve, an angular opening of between 70 and 100 degrees, preferably between 80 and 90 degrees. Furthermore, each intake mouth has, along the circumference of the plug, an angular opening of, for example, between 70 and 100 degrees, preferably between 80 and 90 degrees.

Furthermore, each light 41bp has, along the circumference of the receiving surface 40, an angular opening comprised, for example, between 40 and 100 degrees.

Preferably, the intake and exhaust ports have, along the circumference of the valve, an angular opening of between 30 and 60 degrees, preferably between 40 and 55 degrees.

Between the part of the low pressure valve communicating selectively with cylinder a and the part of the low pressure valve communicating selectively with cylinder b, the mouths and orifices are respectively diametrically opposed according to the embodiment shown.

Concerning cylinder b and depending on the particular angular position of the low pressure valve, the synchronization of the engine is such that no mouth coincides with the ports 41b of the cylinder head. In reference to the figure 7a , we can see that the low pressure valve comprises two inlet openings 32b intended to communicate with two ports 41b so that the working gas coming from the low pressure connection 70 can circulate from the low pressure valve (passing through an orifice admission 34b not visible on the figure 7a ) towards the working chamber of cylinder b. It can also be seen in part that the low pressure valve 30 comprises two exhaust mouths 31b intended to communicate respectively with the two ports 41b of the cylinder head 4 so that the working gas can circulate from the working chamber of the cylinder b towards the low pressure connection 70. It can also be seen that the low pressure valve 30 includes an exhaust port 33b. The exhaust mouths 31b on the one hand, and the exhaust port 33b on the other hand correspond to the two ends of the internal passage allowing the working gas coming from the working chamber of cylinder b to circulate towards the low pressure connection.

There figure 8a shows in particular the angular position of the low pressure valve 30 when working gas escapes from the working chamber of cylinder b. With reference to figure 8a , the two exhaust mouths 31b of the low pressure valve 30 are seen in transparency of the circumference of the valve and conform to the exhaust mouths of the figure 7a . The two exhaust ports 31b form the entrance to the internal passage, also seen transparently, up to the exhaust port 33b. The synchronization of the engine is such that the exhaust ports 31b communicate with the ports 41b of the cylinder head 4 so that the working gas circulates from the working chamber of the cylinder b towards the low pressure plug, and simultaneously the orifice d exhaust 33b, conforming to the exhaust port of the figure 7a , communicates with the port 75 of the low pressure connection 70 so that the working gas circulates from the low pressure valve to the low pressure connection. In reference to the figure 8b , the exhaust mouth 31b coincides perfectly with the port 41b of the cylinder head, and the exhaust port 33b coincides perfectly with the port 75 of the low pressure connection. The movement of piston 3 is such that the working gas is pushed back into the internal passage of the low pressure valve 30 then towards the low pressure connection 70, see arrow fD.

With reference to figures 7a And 8a , the exhaust orifices 33a and 33b are aligned circumferentially along the periphery of the low pressure valve 30. Said orifices are opposed for example by 180 degrees and the internal passages upstream of said orifices are adjoining and have a common wall. During operation of the engine, each orifice successively communicates an internal passage associated with a single exhaust port 75 of the low pressure connection. This characteristic makes it possible to reduce the size of the bushel and therefore the size of the engine.

Furthermore, each pair of lights 41bp is spaced from one another along the receiving surface 40 so that the orifices exhaust are facing the receiving surface 40 of the cylinder head 4 separating the pair of light 41a from the pair of light 41b. Preferably, the spacing between the two pairs of lights is equal to or greater than the transverse dimension of an exhaust orifice.

Claims (14)

1. An external hot source engine (1) comprising:

   - at least one cylinder (2),

   - a piston (3) moving back and forth in the cylinder (2),

   - a cylinder head (4) defining, with the piston (3) and the cylinder (2), a working chamber (5) for a working gas,

   - a distribution mounted in the cylinder head (4) and selectively communicating the working chamber (5) with the following resources:

   • a working gas intake (A),

   • a cold end (B) of a heat exchanger (6),

   • a hot end (C) of the heat exchanger (6),

   • an exhaust (D),

   characterized in that the distribution comprises at least one rotary slide valve (20, 30) mounted in rotation in the cylinder head (4) and including internal passages opening through the sidewall thereof by at least two holes (21, 22, 31, 32) for at least one same passage, said holes (21, 22, 31, 32) being adapted for simultaneously communicating with the working chamber (5), by at least one opening (41) made in the cylinder head (4),

   and in that the internal passages lead to the working gas between the working chamber and the resources.
2. The engine (1) according to claim 1, characterized in that at least one opening (41) of the cylinder head is adapted for communicating with two internal passages of the slide valve which open through the sidewall of the slide valve by two circumferentially aligned holes (21, 22; 31, 32).
3. The engine (1) according to claim 2, characterized in that said two internal passages are, one, is a passage through which the working gas enters in the working chamber (5), and the other, is a passage through which the working gas leaves the working chamber (5).
4. The engine (1) according to any of claims 1 to 3, characterized in that at the end opposite the holes (21, 22; 31, 32), the internal passages open through the sidewall of the slide valve (20, 30) by orifices (23, 24; 33, 34) which selectively communicate with fixed connectors (60, 70) according to the angular position of the slide valve.
5. The engine (1) according to claim 4, characterized in that, for each passage, the geometry of the at least one slide valve (20, 30) is such that the orifice (23, 24; 33, 34) is adapted for communicating with the corresponding connector (60, 70) when the hole (21, 22; 31, 32) communicates with the working chamber (5).
6. The engine (1) according to claim 4 or 5, characterized in that, on the at least one slide valve (20, 30), the at least one hole (21, 22; 31, 32) is axially offset relative to the at least one orifice (23, 24; 33, 34).
7. The engine (1) according to any of claims 1 to 6, characterized in that the at least one slide valve comprises a low-pressure slide valve (30) controlling the selective communication of the working chamber (5) with the intake (A) and the exhaust (D).
8. The engine (1) according to any of claims 1 to 7, characterized in that the at least one slide valve comprises a high-pressure slide valve (20) controlling the selective communication of the working chamber (5) with the hot (C) and cold (B) ends of the exchanger (6).
9. The engine (1) according to claim 8, characterized in that the distribution is arranged so that, at the end of the compression, the working chamber (5) begins to communicate with the cold end (B) of the exchanger (6) when the pressure in the working chamber is lower than the pressure in the exchanger (6).
10. The engine (1) according to any of claims 1 to 9, characterized in that at least one passage comprises two passages leading in parallel to a same resource, adapted for simultaneously communicating each with one opening (41) of the cylinder head.
11. The engine (1) according to any of claims 1 to 10, having at least two cylinders, characterized in that the at least one slide valve (20, 30) includes two orifices circumferentially aligned to selectively communicate with a same connector, and which communicate each with a respective passage associated with a respective one of the cylinders.
12. The engine (1) according to any of claims 1 to 11, characterized in that the openings (41) are surrounded by a sealing device to close the gap between the peripheral wall of the slide valve and an adjacent surface of the cylinder head all around each opening (41).
13. An engine drive assembly comprising an engine (1) according to any of claims 1 to 12 and a heat exchanger (6) having a heat receiving path (62) extending between a cold end (B) and a hot end (C) selectively connected to the working chamber (5) at the end of a compression phase and at the beginning of an expansion phase, respectively.
14. The assembly according to claim 13, characterized in that the heat exchanger (6) comprises a heat yielding path (61) traveled by the exhaust gases of an internal combustion engine.

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