FR3105295A1 - Two-part coaxial bushel, and external hot-source motor comprising the latter - Google Patents

Abstract

Valve in two coaxial parts, and external hot source engine comprising the same The present invention relates to a valve (10) for an external hot source engine (1) of the type comprising: a cylinder (2), a piston (3), a cylinder head (4), a working chamber (5) for a working gas, a distribution comprising said valve selectively making the working chamber communicate with different resources. The valve (10) comprises two coaxial parts: a guide part (11) of the working gas, comprising internal passages emerging radially through at least one mouth which communicates selectively with the working chamber (5) through at least one port ( 41) made in the cylinder head (4), and a distribution part (16) of the working gas, movable and arranged on the periphery of the guide part (11), comprising at least one window (17) which selectively communicates the working chamber (5) with at least one of said internal passages so that the working gas flows selectively between the working chamber (5) and the different resources. The present invention also relates to an external hot source engine comprising said valve. Figure for the abstract: Fig. 3

Description

Valve in two coaxial parts, and external hot source engine comprising the same

The present invention relates to a plug for an engine with an external hot source of the type comprising: at least one cylinder, at least one piston, a cylinder head, a working chamber for a working gas, a distribution comprising said plug and selectively communicating the chamber working with different resources. The plug comprises two coaxial parts:

- a part for guiding the working gas, comprising internal passages opening out radially via at least one opening which communicates selectively with the working chamber via at least one opening made in the cylinder head, and

- a working gas distribution part, movable and arranged on the periphery of the guide part, comprising at least one window which selectively causes the working chamber to communicate with at least one of said internal passages so that the working gas selectively flows between the working chamber and the various resources. It also relates to an external hot source engine equipped with said valve.

State of the prior art

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

For volumetric machines such as in particular internal combustion piston engines, timing systems 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 valve lift is low if the duration (measured in degrees of cam rotation angle) of valve opening is short. In addition, the cam drive consumes energy.

Volumetric machines are also known, such as compressors, which use valve distribution. This solution requires that the pressure differential on each valve always has, at each stage of the operating cycle of the machine, 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 2905728 and FR 2954 799, air taken from the atmosphere is admitted and compressed in a working chamber, then transferred to a source hot, and from there re-transferred to the same working chamber at the start of a period of expansion of this chamber, producing mechanical energy collected by a piston, then evacuated to the atmosphere.

To be effective, the two transfers of the working gas, from the working chamber to the hot source then from said hot source to said working chamber, must be brief and take place through a passage section large enough to minimize the load losses. These requirements are difficult to meet with valve timing controlled by cams. Furthermore, this type of cycle is not easily compatible with valve distribution.

Patent application FR 3069884 discloses an external hot source engine comprising bushels. Each slider is rotatably mounted in the cylinder head and has 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. Each bushel is made from a single piece. The bushel offers a larger passage section for the working gas and makes it possible to reduce pressure drops between the working chamber and the resources. Although satisfactory, this type of distributor has the following disadvantages:

• significant heat exchanges between the hot flow, coming from the hot end of an exchanger, entering the working chamber and the cold flow leaving the working chamber, reducing the ability to draw heat from the hot resource, And
• a double valve effect in the path of the working gas with a discontinuity between a port of the cylinder head and a mouth of the plug on the one hand, and a port of the plug and a port of a connection of a resource on the other hand, not conducive to the circulation of air between the working chamber and the hot resource.

It is eager to always improve the two gas transfers indicated above and/or to propose efficient technical solutions in order to carry out the two gas transfers in the engine and to increase its performance.

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

According to a first aspect of the invention, at least one of the objectives is achieved with a plug for an external hot source engine of the type comprising:

- at least one cylinder,

- a piston moving back and forth in the cylinder,

- a cylinder head defining, with the piston and the cylinder, a working chamber for a working gas,

- A distribution, including said valve, mounted in the cylinder head and selectively communicating the working chamber with different resources.

The valve is characterized in that it comprises two coaxial parts:

- a part for guiding the working gas, comprising internal passages opening out radially via at least one opening which communicates selectively with the working chamber via at least one opening made in the cylinder head, and

- a working gas distribution part, arranged on the periphery of the guide part and movable relative to the guide part, the distribution part comprising at least one window which selectively causes the working chamber to communicate with at least one of said internal passages so that the working gas selectively flows between the working chamber and the various resources.

The valve according to the invention has the advantages of simultaneously limiting heat losses and pressure losses, and of ensuring better continuity of the flows between the working chamber and the hot resource, thus making it possible to improve the efficiency and/or the performance of an external hot source engine equipped with said valve.

By bushel is meant a cylindrical device comprising internal passages in which the working gas can circulate. An internal passage is for example a duct. The valve is arranged so that its axis of rotation is perpendicular to the axis of the cylinder above which it is arranged. The valve is located between the working chamber and a heat exchanger along the path of the working gas. The plug presented here has the particularity of comprising two coaxial parts: a guide part and a distribution part surrounding the guide part. The rotary movement of one part and/or the other part of the guide part and the valve valve part is/are synchronized with the reciprocating movement of the piston, so that the working gas can pass through the bushel 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 made through the side wall of the guide part 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 by passing through at least one port of the cylinder head, at least one internal passage of the guide part of the valve and at least one opening of the distribution part of the valve.

Called mouth, an opening located at one end of the guide part of the valve. The mouthpiece selectively coincides with at least one slot in the breech. One calls window, an opening of the part of distribution of the bushel. A window selectively coincides with at least one lumen and at least one mouthpiece. A window can coincide with at least one orifice. Called orifice, an opening located at another end of the guide part of the plug. The orifice is located opposite the mouthpiece.

For the foregoing and for the rest of the application, the terms mouth and orifice correspond to, or qualify, openings made through the side wall of the guide part of the plug. The term mouth is used to qualify each opening capable of communicating with the port of the cylinder head for the passage of the working gas from the working chamber to the valve or vice versa. A mouth is always made through the peripheral wall of the guide part, also called the circumferential wall. The term orifice is used to qualify each opening capable of communicating with a connection for the passage of the working gas from the valve to the connection or vice versa. An orifice can be made through the peripheral wall of the guide part, also called the circumferential wall, or through the transverse wall of the guide part. A mouthpiece cannot be used as an orifice and vice versa. For this, in the case where the orifice is made on the peripheral wall of the guide part, the at least one mouth is offset axially with respect to the at least one orifice.

For the foregoing and for the rest of the application, the term window corresponds to, or qualifies, an opening made through the side wall of the valve distribution part. The term window is used to qualify each opening capable of communicating with the port of the cylinder head and a mouth, for the passage of the working gas from the working chamber to the valve or vice versa. In this case, we can use the expression mouthpiece window. In addition, the term window is used to qualify each opening capable of communicating with an orifice and a connection, for the passage of the working gas from the plug to the connection or vice versa. In this case, we can use the expression orifice window. A window can be made through the peripheral wall of the distribution part, also called the circumferential wall, or through the transverse wall of the distribution part.

Finally, the adjectives "hot" and "cold" are understood to have a relative meaning simply meaning that a hot element, for example a hot mouthpiece or a hot orifice, is generally hotter than a cold element, for example a mouthpiece. cold or a cold orifice, when the engine is running.

By side wall is meant, evoking the guide part or the dispensing part, on the one hand a peripheral wall, also called circumferential wall, which extends along a cylindrical face of said part, or on the other share a transverse wall, also called the axial face of said part, which extends along a flat face of said part.

The valve distribution system makes it possible to offer a large section for the passage of the working gas, in particular as soon as a mouth begins to coincide with a window in the distribution part and with a port in the cylinder head. As the speed of rotation of the valve is substantially constant, the passage section increases rapidly, for example linearly, until the mouth coincides perfectly with the port of the cylinder head.

Valve timing allows the following four-stroke type thermodynamic cycle to be carried out:

• a substantially cold working gas is admitted into the working chamber,
• said gas is compressed in said working chamber, then
• transferred to the exchanger in which a heat-transferring fluid (the hot source) circulates, so as to heat the working gas;
• the heated working gas is transferred back 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 exhausted from the working chamber.

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

Preferably, at least one opening of the cylinder head is capable of communicating with two internal passages of the guide part of the plug which open through the peripheral wall of the guide part by two mouths aligned circumferentially, according to the angular position of the part. of distribution.

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.

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” compared to its higher temperature when it leaves the exchanger “hot”. It must however be understood that the “cold” working gas entering the exchanger is already heated by its compression in the working chamber. Similarly, 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 the 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 the operation of the engine and with reference to the cycle described above, the cold and compressed working gas and/or in the process of compression enters the in the guide part of the plug, which is fixed, since at least a window of the rotating distribution part coincides simultaneously with a part of the mouth and with the port 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 mouthpiece increases with the rotation of the distribution part of the valve. When the mouth of the valve coincides perfectly with the opening of the cylinder head, the passage section is maximum. The major part, at least 50%, of the volume of cold and compressed working gas has then passed through said mouth. Then, due to the rotation of the guide part of the valve and the end of the compression, only a part of the mouth coincides with the port, 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 lumen. The working gas leaving the second mouthpiece, 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 leads to making said port larger, and therefore to further increase the passage section offered to the gas to pass through the exchanger and come back. For a short time the cold working gas, leaving the working chamber, and the hot working gas, entering the working chamber, intersect. This avoids an unfavorable phenomenon of relatively low pressure in the working chamber at the start of the expansion phase.

Preferably, the section of the light is at least equal to the sum of the sections of the hot and cold mouthpieces. Preferably, the section of the light is at least equal to the sum of the sections of the hot and cold mouthpieces and of the cross section of the wall separating the hot mouthpiece from the cold mouthpiece.

According to an exemplary embodiment, the two neighboring mouthpieces are aligned circumferentially and offset by an angle of between 5 and 15 degrees.

These values, like other angular values provided later, concerning the mouths, orifices and windows, are indicated for a speed of rotation of the valve between 1000 and 3000 rpm (revolutions per minute), preferably between 2000 and 3000 rpm (revolutions per minute). In addition, the nominal pressure prevailing in the heat exchanger can be between 4 and 5 bar absolute and the heat-transferring fluid can have a temperature between 500°C and 900°C (degrees Celsius).

According to a preferred embodiment, the guide part is fixed relative to the motor. Since most of the bushel is static, the gases are on the one hand less disturbed when flowing through the bushel. In addition, the heat of the hot gases is on the other hand less dissipated by convection and/or conduction of the internal and/or external surface of the internal passage(s) of the valve, or of the external surface of the valve with regard to the cylinder head. In particular, the heat of the hot gases is less dissipated by convection and/or conduction from the internal and/or external surface of the internal passage(s) of the plug compared to the internal passage(s) in which cold gases flow. By hot gas relative to cold gas, we mean a hot gas which has a higher temperature than that of a cold gas. This makes it possible to limit or avoid the decrease in the temperature difference between the hot part of the bushel and the cold part of the bushel; the engine principle residing on the temperature difference between the hot source and the cold source.

Finally, there is a synergistic effect. As gas flow is facilitated, heat dissipation is reduced. With regard to the prior art, the temperature difference between the hot gases and the cold gases within the engine is maximized, making it possible to obtain a significantly improved efficiency, at least beyond the addition of the two effects taken separately.

Preferably, the guide part comprises at least one orifice, arranged at the end of an internal passage opposite the at least one mouth, so that the internal passages open through a wall of the guide part of the plug by the at least one orifice which allows the internal passage to communicate with a corresponding fixed connection. A fixed connection connects the engine with a resource, for example a cold or hot end of an exchanger.

According to a first embodiment, the at least one orifice is arranged on a peripheral wall of the guide part. This characteristic has the advantage of causing the gases to cross radially in the valve and thus makes it possible to limit the travel distance of the gases between the working chamber and the resources. According to one example, the guide part may comprise two orifices, a cold orifice and a hot orifice, arranged on the peripheral wall.

According to a second embodiment, the at least one orifice comprises two orifices: an orifice arranged on a peripheral wall of the guide part and an orifice arranged on a transverse wall of the guide part. Preferably, the at least one orifice comprises two orifices: an orifice, called cold orifice, arranged on a peripheral wall of the guide part and an orifice, called hot orifice, arranged on a transverse wall of the guide part. This feature has the advantage of limiting heat transfer between the internal passages, in which hot gases and cold gases respectively flow, from the internal passage containing a hot gas to an internal passage containing a cold gas or vice versa, because the distance of the hot orifice from the cold orifice.

According to a third embodiment, the at least one orifice is arranged on a transverse wall of the guide part. This characteristic has the advantage of leaving at least one orifice constantly open, and thus of limiting the loss of pressure. The guide part may comprise two orifices, a cold orifice and a hot orifice, arranged on a transverse wall. According to a first example, the two orifices can be arranged on the same transverse wall, or the same axial face. According to a second example, each orifice is arranged on a distinct opposite transverse wall.

Preferably, the dispensing part is generally tubular in shape. The dispensing part includes at least one radially directed window arranged and configured to, during a rotation of said part, selectively align with at least one mouth of the valve guide part.

According to one embodiment, the dispensing part is of generally tubular shape, and the dispensing part comprises at least one window arranged and configured to selectively align itself, during a rotation of said part, with at least one orifice of the guide part of the plug. According to an embodiment compatible with the first and the second embodiment of the guide part, the dispensing part is of generally tubular shape, and the dispensing part comprises at least one window directed radially and arranged to selectively align with at least one mouth, and at least one radially directed window arranged to align with at least one orifice.

The distribution part may further comprise, for a cylinder, the same window directed radially, selectively communicating one or the other of two internal passages with the working chamber. In one embodiment particularly compatible with the third embodiment of the guide part, the dispensing part comprises, for a cylinder, a single radially directed window.

According to one embodiment, the at least one mouthpiece comprises two mouthpieces for the same internal passage, capable of communicating simultaneously with the working chamber, through two ports. Each mouthpiece 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 drop of said flow and limiting the leaks of working gas between the plug and the cylinder head.

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

Preferably, the openings and the openings 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 equip the mouths of the low pressure valve as well as those of the high pressure valve.

For the above and for the rest of the description, a mullion is understood to mean a bar designed 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 mouthpiece so as to extend the circumference of the plug.

According to one 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 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 lines of flow are divided before entering the two ports of the valve and meet after the exit of the two openings of the cylinder head.

According to one option, the guide part comprises at least one cavity arranged between the internal passages of the guide part, the cavity forming an axially directed channel. This cavity can allow the introduction of a gas in order to heat the internal passages.

According to a second aspect of the invention, at least one of the objectives is achieved with an external hot source engine comprising:

- at least one cylinder,

- a piston moving back and forth in the cylinder, being connected to a motor shaft,

- a cylinder head defining, with the piston and the cylinder, a working chamber for a working gas,

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

- a working gas inlet,

- a cold end of a heat exchanger,

- a hot end of the heat exchanger,

- an exhaust,

characterized in that it comprises at least a first valve arranged according to one or more of the characteristics of the first aspect.

According to optional improvements of the invention:
- the engine comprises a second valve, called low pressure, controlling the selective communication of the working chamber with the intake and the exhaust, the second valve comprising internal passages emerging radially via at least one mouth which communicates selectively with the chamber work by at least one light made in the cylinder head,
- the second plug comprises a radially directed orifice and an axially directed orifice, each orifice being arranged at the end of the corresponding internal passage opposite its mouth,
- the second valve is a low pressure valve controlling the selective communication of the working chamber with the intake and the exhaust, and the first valve is a high pressure valve controlling the selective communication of the working chamber with the hot ends and heat exchanger cold; this characteristic makes it possible to simplify the construction of the motor by separating the so-called "high pressure" flows and the so-called "low pressure" flows and to reduce its size
- the bushels can have identical diameters, making it possible to simplify the construction of the engine,
- the bushels can have different diameters, for example the first so-called high pressure bushel can be of a diameter greater than the diameter of the second so-called low pressure bushel, this characteristic makes it possible to further enlarge the passage section of the internal passages, going to the interchange and coming back;
- the motor comprises means for driving one of the parts of the slider at a speed proportional to the speed of the motor shaft,
- the motor comprises means for driving the distribution part of the valve at a speed proportional to the speed of the motor shaft,
- the engine comprises, alternatively to the second bushel, a valve train, of the type used for internal combustion engines,
- the motor includes two fixed connections, a so-called “high pressure” connection and a so-called “low pressure” connection,
- the high pressure connector comprises a cold connector communicating with the cold end of the exchanger and a hot connector communicating with the hot end of the exchanger,
- The low pressure connector comprises an inlet connector, communicating with the inlet of the working gas, and an exhaust connector communicating with the exhaust of the working gas.

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 valve and the low pressure valve, which are arranged parallel to each other seen parallel to the axis of the valve.

According to other embodiments, the external hot source engine can 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 some of the characteristics described so far.

In the case of two or more cylinders, the valve is potentially the same for all the cylinders which are arranged in line with each other. According to another embodiment, one bushel is provided per cylinder.

Preferably, the engine includes sealing devices to limit gas leaks.

According to one embodiment, the ports may be 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 material for dry friction, for example graphite. For example, the strips are arranged around the cylinder head ports.

According to another embodiment, which may be compatible with the previous one, the mouths may be surrounded by sealing devices to close the radial gap between the guide part and the valve distribution part.

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 set out above and a heat exchanger having a heat-receiving path s' 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 an expansion phase, respectively. The working gas flows through the heat sink path.

Preferably, the exchanger is of the counter-current type. The heat exchanger comprises a heat-transferring path traversed 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 heat-transferring path is distinct from the heat-receiving path.

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 by solar energy.

Other advantages and features of the invention will appear on reading the detailed description of implementations and non-limiting embodiments, and the following appended drawings:

figure 1 comprises two figures 1a and 1b showing two schematic representations of an external hot source engine, comprising two valves, a low pressure valve, to the left of each of figures 1a and 1b, and a high pressure valve, to the right of each of FIGS. 1a and 1b, comprising two coaxial parts according to the invention, a guide part and a distribution part, the high-pressure valve being illustrated according to a first embodiment, in which the guide part comprises internal passages, each internal passage opening radially through a mouthpiece and an orifice, the dispensing part comprising a radially directed mouthpiece window arranged to selectively align with a mouthpiece, and a radially directed orifice window arranged to selectively align with an orifice, the engine being coupled with a heat exchanger, the engine and exchanger assembly being seen in section during two main operating phases of the engine: FIG. 1a illustrating a phase of admission of a working gas into the engine cylinder, FIG. 1b illustrating a gas exhaust phase from said cylinder;

figure 2 comprises three figures 2a, 2b and 2c showing three schematic representations of an engine according to figure 1, the motor and exchanger assembly also being seen in section during three main operating phases of the engine: figure 2a illustrating a phase of end of compression of the working gas and during which the gas is also directed towards a cold end of the heat exchanger, FIG. 2b illustrating a phase in which a valve has a so-called “scavenging” position which allows simultaneous fluid communication of the cold end and the hot end of the exchanger with the cylinder of the engine, FIG. 2c illustrating a phase of expansion of the working gas after it has passed through the exchanger;

FIG. 3 is a cross-sectional view of an engine comprising a low-pressure valve, on the right of the figure, and a high-pressure valve, on the left of the figure, comprising two coaxial parts, the section plane being perpendicular to the axes of the valves, FIG. 3 illustrating a phase at the end of compression of the working gas and showing the position of the various moving parts, including the angular position of the valves, in particular the angular position of the distribution part relative to the guide part of the upper valve pressure, the position of the dispensing part being such that a window is angularly offset by a few degrees relative to a cold mouthpiece;

Figure 4 is a zoom of the high pressure valve of Figure 3;

Figure 5 is a zoom of the high pressure valve according to Figures 3 and 4, Figure 5 illustrating a position in which the window of the distribution part is centered relative to a cold mouthpiece;

Figure 6 is a zoom of the high pressure valve according to Figures 3 and 4, Figure 6 illustrating a position in which the window of the distribution part is angularly offset by a few degrees relative to a cold mouthpiece and also to a hot mouthpiece;

Figure 7 is a zoom of the high pressure valve according to Figures 3 and 4, Figure 7 illustrating a position in which the window of the distribution part is centered relative to a hot mouthpiece;

FIG. 8 is a zoom of the high pressure valve in accordance with FIGS. 3 and 4, FIG. 8 illustrating a position in which the window of the dispensing part is angularly offset by a few degrees relative to a hot mouthpiece so that said window of the distribution part no longer coincides with the hot mouthpiece;

FIG. 9 is an exploded perspective view of a high pressure valve according to a second embodiment of the invention, the valve comprising a distribution part and a guide part, the guide part comprising two cold mouthpieces and two mouthpieces hot, the distribution part comprising only two windows, called mouth windows, the distribution part being provided to cover the guide part of the plug;

FIG. 10 is an exploded perspective view of a valve according to the same embodiment as FIG. 9, the guide part comprising an orifice, called the cold orifice, arranged on the circumferential wall, the dispensing part comprising a window, said orifice window, arranged on the circumferential wall;

FIG. 11 is a view in longitudinal section of the engine having a high-pressure valve according to the embodiment of FIGS. 9 and 10, the section plane passing through the axis of said valve and through the axis of the piston, FIG. 11 illustrating a phase during which the working gas is in communication with one of the cold ends of the heat exchanger;

FIG. 12 is a zoom of the high pressure valve according to FIGS. 9, 10 and 11, illustrating a phase during which the working gas is directed towards a cold end of the heat exchanger, or else, during which the working gas, coming from a hot end of the heat exchanger, is directed to the working chamber;

Figure 13 is a zoom of the high pressure valve according to Figures 9, 10 and 11, illustrating a phase during which the working gas, coming from a hot end of the heat exchanger, is directed towards the chamber of work, or else, during which the working gas is directed to a cold end of the heat exchanger;

FIG. 14 is an exploded perspective view of a high pressure valve according to a third embodiment of the invention, the valve comprising a distribution part and a guide part, the guide part comprising two cold mouthpieces and two mouthpieces hot, the distribution part comprising two windows, called mouth windows, the distribution part being provided to cover the guide part of the plug;

figure 15 comprises two figures 15a and 15b showing two perspective views of a guide part of a valve according to the embodiment of figure 14, in which two orifices are arranged on a transverse wall, the valve being provided for an engine comprising a cylinder, FIG. 15a showing the valve in transparency so as to visualize the internal passages;

FIG. 16 is a view in longitudinal section of an engine having a high-pressure valve according to FIGS. 14 and 15, the section plane passing through the axis of said valve and through the axis of the piston, FIG. 16 illustrating a phase during which the working gas is directed to a cold end of the heat exchanger.

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

Figures 1a, 1b, 2a, 2b and 2c illustrate the main operating phases of an engine with an external hot source 1, and will make it possible to describe the engine comprising valves according to one embodiment. The engine includes:

• an engine block in which is formed a cylindrical cavity called cylinder 2,
• a movable piston 3 arranged to move back and forth in the cylinder 2,
• a cylinder head 4 covering the engine block above cylinder 2, a working chamber 5 being delimited for a working gas, typically air, in cylinder 2 between piston 3 and 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 inlet 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 the heat-receiving fluid, and a heat-transferring fluid. The heat exchanger 6 is of the countercurrent type. It comprises a heat-transferring path 61 traversed by the heat-transferring fluid from left to right. It further comprises a heat-receiver path 62, shown below the heat-transfer path 61, with reference to FIGS. 1a to 2c, so that the working gas travels the heat-receiver path from right to left. The heat-transferring path is distinct from the heat-receiving path. The heat-transferring fluid is, for example, the exhaust gases of an internal combustion engine.

The heat exchanger 6 is connected to the engine via fittings 60, see figures 11 and 16, and pipes so as to be able to circulate the working gas from the engine to the exchanger and vice versa. Similarly, one or more fittings or pipes are connected to the engine to make the intake and the exhaust.

The distribution comprises two bushels, a first bushel 10, called "high pressure" bushel, and a second bushel 30, called "low pressure" bushel, mounted in the cylinder head 4, above the working chamber 5. Each bushel has the general shape of a cylinder. The axes of the two valves are parallel to each other and orthogonal to the axis of the cylinder 2. The low pressure valve 30 is arranged and configured to control the selective communication of the working chamber 5 with the inlet A and the exhaust D. The high pressure valve 10 is 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 10 is used only to control the circulation of the working gas between the working chamber and the exchanger. Similarly, the low pressure valve 30 is used only to control the intake and exhaust. This characteristic makes it possible to simplify the construction of the motor by separating the so-called “high pressure” flows and the so-called “low pressure” flows and to reduce its size. The valves have, for example, but not necessarily, identical diameters making it possible to simplify the construction of the engine. The low-pressure valve 30 is made in one piece or in one piece and is rotatably mounted in the cylinder head 4. The high-pressure valve 10 is made in two coaxial parts: a so-called “guide” part 11 and a called "distribution" 16. The guide part 11 has a generally cylindrical shape and is fixed relative to the cylinder head 4. The distribution part 16 has a generally tubular shape which surrounds the guide part 11 and which is rotatable relative to the guiding part. The distribution part 16 of the high pressure valve is rotatably mounted in the cylinder head 4. Only the distribution part is rotary as regards the high pressure valve.

Each bushel 10, 30 includes internal passages to conduct 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 plug, each with at least one opening. The distribution is arranged and configured so that the rotary movements of the valves are synchronized with the reciprocating movement of the piston, so that the working gas can pass through the valves via the internal passages. The apertures are arranged and configured to selectively coincide with at least one lumen in the cylinder head and at least one lumen in a fixed fitting. The mouth is the opening opposite the bore of the cylinder head during the passage of the working gas between the working chamber and the valve or vice versa. An orifice is the opening facing a fitting when the working gas passes between the plug and said fitting or vice versa. A mouthpiece cannot be used as an orifice and vice versa. For this, the orifices have an axial offset with the mouths. The mouth window is the opening facing both a mouth and a port when the working gas passes between the working chamber and the valve or vice versa. The orifice window is the opening opposite both an orifice and a fitting during the passage of the working gas between the plug and the said fitting or vice versa.

According to one embodiment of an engine comprising a single cylinder, the low pressure valve comprises:

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

the guide part of the high pressure valve comprises, according to any embodiment of the guide part:

• 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, and

the distribution part of the high pressure valve comprises, according to any embodiment of the distribution part, at least one window, called the mouth window, for the transfer of the working gas from the working chamber 5 towards the cold end B of exchanger 6, then for the transfer of working gas from the hot end C of exchanger 6 to working chamber 5.

Valve distribution allows the thermodynamic cycle to be carried out, the main phases of which will now be described.

Figures 2a, 2b and 2c schematically illustrate an engine comprising a high pressure valve made according to a first particular embodiment; said Figures 2a, 2b and 2c showing a high pressure valve comprising two mouths and two orifices arranged on the peripheral wall of the guide part of the high pressure valve.

According to a first embodiment similar to that of FIG. 9, the high pressure valve comprises two cold mouthpieces 21 and two hot mouthpieces 22 arranged on the peripheral wall of the guide part 11, and two mouthpiece windows 17 arranged on the peripheral wall of the distribution part 16, each window 17 being provided to overlap successively above a cold mouth 21 then a hot mouth 22, during operation. According to one embodiment, the guide part comprises a single cold mouthpiece and a single hot mouthpiece, and the dispensing part comprises a single mouthpiece window.

Figure 10 shows a high pressure valve according to Figure 9, rotated through an angle of approximately 180 degrees, comprising a cold orifice 23 arranged on the peripheral wall of the guide part 11, and an orifice window 19 , called cold orifice window, arranged on the peripheral wall of the distribution part 16, said window being provided to be superposed on said orifice during operation. According to the first embodiment not shown, but similar to that of Figure 10, the high pressure plug comprises two orifices, a cold orifice 23 and a hot orifice 24 (see Figure 2c), arranged on the peripheral wall of the part of guide 11, and two orifice windows 19, a cold orifice window 19c (see FIGS. 2a, 2b) and a hot orifice window 19h (see FIGS. 2b and 2c), arranged on the dispensing part. The cold orifice 23 is offset axially relative to the cold 21 and hot 22 mouthpieces. The hot orifice is axially offset relative to the cold 21 and hot 22 mouthpieces. This arrangement is not limiting. Other arrangements of the holes on the guide part will be described in more detail below.

In addition, Figures 3, 4, 5, 6, 7 and 8 illustrate a first high pressure valve according to one embodiment and seen in section. These figures show the rotation of the distribution part of the high pressure valve relative to the guide part of said valve and relative to the cylinder head of the engine, during operation of the engine in addition to Figures 1a, 1b, 2a, 2b and 2c. In particular, the angular displacement of a mouthpiece window 17 is shown, relative to the cold 21 and hot 22 mouthpieces and relative to the bore of the breech.

Referring to Figure 1a, there is illustrated the phase of admission of a working gas into the working chamber 5. The synchronization of the piston 3 and the valves 10, 30 is such that the movement of the piston 3 is downward during that the rotation of the low pressure valve 30 allows an intake 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 connection . The working gas passes through the internal passage between the inlet orifice 34 and the inlet mouth 32 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 outside environment. When the piston has reached bottom dead center, the low pressure slider 30 has pivoted so that the inlet mouth 32 of the low pressure slider no longer communicates, even partially, with a port in the cylinder head (apart from any closing delay admission).

Then the piston rises so that the trapped working gas is compressed in the working chamber. Referring to Figures 3 and 4, the synchronization of the piston 3 and the distribution part 16 of the high pressure valve 10 is such that the movement of the piston 3 is upwards while the rotation of the distribution part 16 takes place in the clockwise direction. The dispensing part comprises a window, called the mouth window 17. With reference to FIG. 4, the mouth window 17, whose opening length is represented by a dotted circular arc, is located in a position angle shifted by a few degrees with respect to the cold mouth 21, whose opening length is represented by an arrow with two opposite points, and with respect to the opening 41 of the cylinder head, so that part of the said window begins to fit between the cold mouthpiece 21 and said light 41.

Referring to Figure 2a, there is illustrated an end compression phase of the working gas. The synchronization of the piston 3 and the valves 10, 30 is such that the movement of the piston 3 is upwards while the rotation of the distribution part 16 of the high pressure valve 10 allows the mouth window 17 to be inserted radially between a lumen of the breech and a cold mouthpiece 21. Referring to Figure 5, the mouthpiece window 17 is centered relative to the opening of the cold mouthpiece 21. This position has the effect of communicating the cold mouthpiece 21 of the guide part with the lumen of the cylinder head so that the working gas enters the associated internal passage. Simultaneously, the synchronization allows a window, called the cold port window 19c, to be inserted between the cold port 23 and a slot of a connection of the cold end B of the exchanger 6. This position has the effect of communicating the cold orifice 23 and the light of a connection of the cold end B of the exchanger 6 so that the working gas enters said connection. The working gas passes through the internal passage between the cold mouth 21 and the cold orifice 23 so as to be transferred to the exchanger 6 to be heated. Simultaneously, no mouth of the low pressure valve communicates with a port of the cylinder head. The synchronization of the distribution part 16 of the high pressure valve with respect 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.

Referring to Figure 2b, the synchronization of the piston 3 and the valves 10, 30 is such that the piston 3 is at top dead center, or a position close to top dead center, while the rotation of the dispensing part of the high pressure valve 10 allows the mouthpiece window 17 to position itself circumferentially simultaneously partially opposite the cold mouthpiece 21 and partially opposite the hot mouthpiece 22, so as to achieve a double circulation of working gas inside the high pressure valve. Referring to Figure 6, the mouthpiece window 17 is located circumferentially between the cold mouthpiece 21 and the hot mouthpiece 22 so that said window 17 overlaps the wall separating the cold internal passage from the hot internal passage. The cold mouth 21 and the hot mouth 22 of the guide part 11 each coincide at least partially with the same light 41 of the cylinder head.

Simultaneously, the synchronization allows the cold port window 19c to be positioned partially opposite the cold port 23 and partially with the same lumen of a connection of the cold end B of the exchanger 6, than before. A so-called cold internal passage of the guide part allows the working gas to be transferred from the working chamber to the exchanger 6, via the cold end B.

In addition, simultaneously the synchronization allows an orifice window, called hot orifice window 19h, to be positioned partially opposite a hot orifice 24 and a lumen of a hot end connection C of the exchanger 6, so as to cause the hot orifice 24 to coincide at least partially with a hole in 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, to the working chamber 5.

A 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 and intersect. Working gas still passes through the internal passage between the cold mouthpiece 21 and the cold port 23, and working gas passes through the internal passage between the hot port 24 and the hot mouthpiece 22. The volume of gas previously compressed 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 by the heat-transferring fluid present in the heat-transferring path 61 of the exchanger 6. The heated working gas leaving the hot mouth 22 begins to expand. Simultaneously, no mouth of the low pressure valve communicates with a port of the cylinder head.

Then the heated working gas coming out of the high-pressure valve expands into the working chamber. Referring to Figure 2c, the synchronization of the piston 3 and the high pressure valve 10 is such that the movement of the piston 3 is downward while the rotation of the distribution part 16 of the high pressure valve 10 allows the mouthpiece window 17 to be inserted radially between the slot 41 of the cylinder head and the hot mouth 22 of the guide part. Referring to Figure 7, the mouthpiece window 17 is centered relative to the opening of the hot mouthpiece 22. This position has the effect of communicating the hot mouthpiece 22 of the guide part with the slot 41 of the cylinder head so that the working gas can exit the hot internal passage and enter the working chamber.

Simultaneously, the synchronization of the motor allows the hot port window 19 o'clock to be inserted between the hot port 24 and the port of a connection of the hot end C. This position has the effect of communicating the port hot 24 with the same port 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 heat exchanger 6 towards the working room to be relaxed.

Simultaneously, no mouth of the low pressure valve communicates with a port of the cylinder head. Once the piston has reached bottom dead center, neither high-pressure valve mouth communicates with a port in the cylinder head. According to one embodiment, no mouth of the high pressure valve communicates with a port of the cylinder head before the piston reaches its bottom dead center.

With reference to FIG. 1b, an exhaust phase of the working gas is illustrated. The synchronization of the piston 3 and the valves 10, 30 is such that the movement of the piston 3 is upwards while the rotation of the low pressure valve 30 allows an exhaust mouth 31 of the low pressure valve to communicate with a port of the cylinder head and simultaneously allows an exhaust port 33 to communicate with a lumen 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. Referring to Figure 8, the clockwise rotation of the dispensing part is such that the mouth window 17 is angularly offset by a few degrees so that the latter is no longer and is not vis-à-vis, even partially with the hot mouthpiece 22. The working gas is released into the external environment. When the piston has reached top dead center, the low pressure slider has pivoted so that the exhaust mouth 31 of the low pressure slider no longer communicates, even partially, with a port in the cylinder head (apart from any exhaust closing delay ).

Thanks to the valve, the transfers of the working gas are brief and take place through a passage section large enough to minimize pressure drops. In addition, heat transfers between the working gas and the walls of the high pressure valve are minimized, in particular concerning the gas coming from the hot end of the exchanger and heading towards the working chamber. Furthermore, since 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.

In addition, the hot mouthpieces 22 and the cold mouthpieces 21 are moved apart along the circumference of the plug by a very small angular movement, for example 5 to 15 degrees. The angular travel is chosen so that a port 41 can communicate simultaneously with a cold mouthpiece and a hot mouthpiece.

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. Since the engine performs four main phases and 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 drops and bulk (diameter and length of the bushel). Each cold mouthpiece has, along the circumference of the plug, an angular opening comprised, for example, between 10 and 40 degrees, preferably between 20 and 30 degrees.

In addition, each light has, along the circumference of the receiving surface 40, an angular opening comprised, for example, between 15 and 30 degrees.

Preferably, each orifice has, along the circumference of the plug, an angular opening of between 100 and 350 degrees, preferably between 120 and 150 degrees.

We will now describe two other specific embodiments of the high pressure valve, which will be described in their differences with the above embodiment. The two high pressure valves described below are arranged to cooperate with a single cylinder, see figures 11 and 16.

Referring to Figures 9, 10, 11, 12 and 13, there is shown a second embodiment of a high pressure valve of the type comprising a guide portion having a radial cold orifice and an axial hot orifice.

The high pressure valve 10 comprises a guide part 11 having the shape of a cylinder. The guide part comprises a base arranged at one end, in order to fix it to the cylinder head. The guide part 11 comprises on its peripheral surface two mouths, called cold mouths 21, adjacent and axially aligned. It further comprises two other mouthpieces, called hot mouthpieces 22, adjacent and axially aligned. The cold mouthpieces 21 are aligned circumferentially with the hot mouthpieces 22. The mouthpieces have a rectangular shape. The cold and hot mouthpieces each have a substantially rectangular shape whose longitudinal dimension extends in a direction which is parallel to the axis of the plug. The shape and opening dimensions of the cold mouthpieces are substantially identical to the shape and opening dimensions of the hot mouthpieces.

The high pressure valve 10 includes a distribution part in the shape of a tube. The distribution part comprises a pivot shaft 26 which is arranged at one end of said distribution part. The distribution part comprises on its peripheral surface two windows, called mouth windows 17, aligned axially. The mouthpiece windows 17 have a shape and opening dimensions substantially identical to the shape and dimensions of the mouthpieces. In addition, the axial spacing of the windows is identical to that of the mouths 21, 22.

Figure 10 shows the valve in Figure 9 rotated angularly by approximately 180 degrees. The guide part 11 comprises on its peripheral surface a single orifice, called the cold orifice 23. With regard to FIG. 9, the cold orifice 23 is offset axially with respect to the cold 21 and hot 22 mouths. a rectangular shape whose longitudinal dimension extends in a direction which is orthogonal or circumferential to the axis of the plug. The dispensing part 16 comprises on its peripheral surface, a window, called the orifice window 19. The orifice window 19 has a shape and opening dimensions substantially identical to the shape and opening dimensions of the hot hole.

Referring to Figures 9, 10, 11, 12 and 13 the dispensing part is provided to cover and surround the guide part.

Figures 11, 12 and 13 show the path of the internal passages of the guide part of the high pressure valve according to Figures 9 and 10. In addition, the guide part comprises a hot orifice 24 opening onto a transverse end, or axial face , of the guide part.

In the foreground of Figures 11 and 12, there is shown the path of two ducts extending from two cold mouths 21. The two ducts meet to form a single duct to the cold orifice 23, forming the internal passages cold. As FIGS. 11 and 12 each illustrate a working gas transfer phase towards the cold end of an exchanger, like FIG. 2a, the mouth windows 17 coincide with the cold mouths 21, and the orifice window 19 coincides with the cold orifice 23. In the background, the hot internal passages are shown.

Referring to Figure 13, there is shown, in the foreground, the path of two ducts extending from two hot mouths 22. The two ducts meet to form a single duct to the hot orifice 24, forming hot internal passages. In the background, the cold internal passages are represented.

This embodiment has the advantage of further dissociating the hot streams from the cold streams and thus of minimizing the heat transfers between these two streams.

According to a variant embodiment not shown, the high pressure plug comprises a guide part having an axial cold orifice and a radial hot orifice.

Referring to Figures 14, 15 and 16, there is shown a third embodiment of a high pressure valve of the type comprising a guide portion having an axial cold orifice and an axial hot orifice. This embodiment will be described in its differences with the above embodiment.

The cold 23 and hot 24 orifices are each arranged on a transverse face or end of the guide part 11. The routing of the cold and hot internal passages is respectively such that the ducts extend from two mouths and join to form a single duct which opens at an axial end of the guide part 11, see figure 16. With reference to figure 15, the hot and cold internal passages are arranged in the guide part in a substantially symmetrical manner with respect to a plane passing through the axis of the guide part.

With reference to Figure 14, the absence of a radially arranged orifice makes it possible to produce a high pressure valve of a shorter length compared to the other embodiments. Furthermore, the distribution part includes only mouthpiece windows.

According to a particular embodiment and with reference to FIG. 14, each mouthpiece comprises a mullion 25 dividing the opening of the mouthpiece into two. In this case, two ducts extend from a mouthpiece, see figures 15 and 16.

According to one embodiment, compatible with the three embodiments of the high pressure valve, the distribution part 16 is driven in rotation by a pulley 28 which sets the distribution part 16 in motion via the pivot shaft 26, see figures 11, 12, 13 and 16.

According to a particular embodiment, compatible with the three embodiments of the high pressure valve, the guide part 11 comprises a cavity 27 arranged between the hot and cold internal passages, see FIGS. 11 and 16. The cavity 27 is intended to receiving and storing a hot gas. This characteristic makes it possible to maintain the highest possible temperature for the working gases coming from the hot end of the exchanger and heading towards the working chamber.

Preferably, the high pressure plug comprises sealing devices arranged between the guide part and the distribution part. Referring to Figures 5 to 8, the sealing devices have the shape of a plate curved in an arc of a circle so as to be inserted between the guide part and the distribution part. Each sealing device comprises a notch at each end so as to produce a central extra thickness which is intended to be placed in a housing 13 of the sealing device arranged on the peripheral surface of the guide part, see FIGS. 9 and 14.

Claims (15)

Valve (10) for an external hot source engine (1) of the type 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, comprising said valve, mounted in the cylinder head (4) and selectively communicating the working chamber with different resources,
characterized in that the plug (10) comprises two coaxial parts:
- a guide part (11) of the working gas, comprising internal passages emerging radially via at least one mouth (21, 22) which communicates selectively with the working chamber (5) via at least one opening (41) made in the cylinder head (4), and
- a distribution part (16) of the working gas, arranged on the periphery of the guide part (11) and movable relative to the guide part (11), the distribution part comprising at least one window (17) which selectively communicates the working chamber (5) with at least one of said internal passages so that the working gas flows selectively between the working chamber (5) and the various resources. Valve (10) according to Claim 1, characterized in that the guide part (11) is fixed relative to the motor (1). Valve (10) according to Claim 1 or 2, characterized in that the guide part (11) comprises at least one orifice (23, 24) arranged at the end of an internal passage opposite the at least one mouth (21, 22), so that the internal passages open through a wall of the guide part (11) of the plug (10) by the at least one orifice (23, 24) which allows the internal passage to communicate with a corresponding fixed connection (60, 70). Valve (10) according to Claim 3, characterized in that the at least one orifice (23, 24) is arranged on a peripheral wall of the guide part (11). Plug (10) according to Claim 3, characterized in that the at least one orifice (23, 24) comprises two orifices: an orifice (23, 24) arranged on a peripheral wall of the guide part (11) and a orifice (23, 24) arranged on a transverse wall of the guide part (11). Valve (10) according to Claim 3, characterized in that the at least one orifice (23, 24) is arranged on a transverse wall of the guide part (11). Valve (10) according to one of Claims 3 to 6, characterized in that the distribution part (16) is of generally tubular shape, and in that the distribution part (16) comprises at least one window (17) arranged and configured to selectively align, during a rotation of said part, with at least one orifice (23, 24) of the guide part (11) of the plug. Valve (10) according to Claim 4 or 5, characterized in that the distribution part (16) is of generally tubular shape, and in that the distribution part (16) comprises at least one window (17) directed radially arranged to selectively align with at least one mouth (21, 22), and at least one radially directed window (17) arranged to align with at least one port (23, 24). Valve (10) according to one of Claims 1 to 6, characterized in that the distribution part (16) is generally tubular in shape. Valve (10) according to one of Claims 1 to 9, characterized in that the distribution part (16) comprises at least one radially directed window (17) arranged and configured for, during a rotation of the said part, selectively aligning with at least one mouth (21, 22) of the guide portion (11) of the plug. Valve (10) according to one of Claims 1 to 9, characterized in that the distribution part (16) comprises, for a cylinder (2), the same window (17) directed radially, selectively causing one or the other of two internal passages with the working chamber (5). Plug (10) according to one of the preceding claims, characterized in that the guide part (11) comprises at least one cavity (27) arranged between the internal passages of the guide part (11), the cavity (27) forming an axially directed channel. External hot source engine (1) comprising:
- at least one cylinder (2),
- a piston (3) moving back and forth in the cylinder (2), being connected to a motor shaft,
- 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 inlet (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 it comprises at least a first plug (10) arranged according to one of the preceding claims. Engine (1) according to the preceding claim, characterized in that it comprises a second valve (30), called low pressure, controlling the selective communication of the working chamber (5) with the inlet (A) and the exhaust (D), the second valve (30) comprising internal passages emerging radially via at least one mouth (31, 32) which communicates selectively with the working chamber (5) via at least one slot (41) formed in the cylinder head ( 4). Motor (1) according to the preceding claim, characterized in that the second plug (30) comprises a radially directed orifice and an axially directed orifice, each orifice being arranged at the end of the corresponding internal passage opposite its mouth.