EP2281107B1 - Engine with a variable volume chamber - Google Patents

Abstract

The invention relates to an engine including: - a cylinder that contributes to define a chamber (3), - a first piston (4), said first piston (4) and cylinder are subjected to a first relative back-and-forth motion, - an output shaft (8), - a second piston (14), said second piston (4) and cylinder are subjected to a second relative back-and-forth motion, said output shaft (8) mounted coaxially to said pistons (4, 14), - a first means for converting (5) said first relative back-and-forth movement into rotational motion of the output shaft (8), including, on one side, a first corrugated guide track (9) and, on the other side, a first guide element (10) designed to move along said guide track (9), - a first adjustment member (5) to position the first guide track (9).

Description

TECHNICAL AREA

The present invention relates to the general technical field of motors, and in particular engines whose operation is based on the variation of volume of a chamber (for example by compression and expansion of a working fluid within the chamber) such engines providing mechanical energy usable for example to propel vehicles (such as automobiles, motorcycles, aircraft or boats), to animate machines (industrial or agricultural), or to provide mechanical energy energy conversion devices, like generators.

• un cylindre qui contribue à délimiter une chambre dont le volume varie entre une valeur minimale et une valeur maximale,
• un premier piston contribuant lui aussi à délimiter ladite chambre, lesdits premier piston et cylindre étant conçus pour-subir un premier mouvement relatif de va-et-vient sous l'effet de la variation du volume de la chambre,
• et un arbre de sortie rotatif.

The invention more specifically relates to an engine comprising at least the following three components:

• a cylinder which contributes to delimit a chamber whose volume varies between a minimum value and a maximum value,
• a first piston also contributing to define said chamber, said first piston and cylinder being designed to undergo a first relative back-and-forth movement under the effect of the variation of the volume of the chamber,
• and a rotary output shaft.

PRIOR ART

Engines using a chamber whose volume variation is used to supply mechanical energy to a receiving system (car, machine or other) are known for a long time and widespread, since internal combustion engines (or " engines engines "), which equip the cars, based on such a principle of operation.

The architecture of these engines is generally blasé on the implementation of a cylinder which is closed in its upper part by a cylinder head. The cylinder and the cylinder head form a combustion chamber whose volume is defined by the stroke of a piston sliding in the cylinder in a reciprocating movement imparted by the pressure variations resulting from the combustion cycles operated in the chamber. of combustion. The piston is itself connected to a crankshaft, via a connecting rod, to transform the rectilinear translation movement of the piston into rotational movement of the crankshaft.

This known engine architecture generally gives satisfaction, but has no less serious disadvantages. In particular, these known motors use a relatively heavy and complex mechanical and kinematic chain of transmission and force transfer between the pistons and the output shaft. This is, of course, a potential source of failure and loss of energy efficiency, and is not intended to increase reliability or reduce cost. In addition, these known motors implement a large number of moving parts, which corresponds to a mass in motion, likely again to cause problems of efficiency and reliability. These known engines also prove to be also relatively heavy and bulky, so that their location within a vehicle, and particularly within a motor vehicle of the particular car type can be problematic, especially with respect to correct positioning of the center of gravity of the engine in the vehicle. Finally, the efficiency of these known engines is not optimal in the different modes of use of the engine, which leads to overconsumption of fuel. In order to remedy this latter problem, it has been proposed to adapt the volume of the combustion chamber according to the level of stress on the engine.

The combustion engines thus modified to allow a dynamic adjustment of the volume of the combustion chamber are generally designated by the term " variable compression ratio engines" or "VCR" engines (for " Variable Compression Ratio "), in as the compression ratio of the air / fuel mixture in the combustion chamber varies with the volume of said chamber. These variable compression engines thus allow an optimization of the efficiency compared to conventional explosion engines, and avoid (or at least minimize) the appearance of undesirable phenomena such as rattling. However, the known variable compression engines also suffer from the drawbacks mentioned above with regard to conventional combustion engines. These disadvantages are even accentuated since the realization of a variable compression ratio chamber is generally obtained, in known VCR engines, by the implementation of complex mechanical control systems of the piston stroke, which not only weigh down the motor and affect the reliability, but are also likely to cause the appearance of undesirable vibration and acoustic phenomena. In addition, the industrialization of these known VCR engines proves tricky, which leads to a significant increase in the cost price of the engine.

SUMMARY OF THE INVENTION

The invention therefore aims to remedy the various disadvantages listed above and to propose a new engine whose performance is optimized and whose architecture is particularly simple, lightweight and reliable.

Another object of the invention is to provide a new construction engine particularly compact and robust.

Another object of the invention is to propose a new engine of particularly simple design and easy to manufacture.

Another object of the invention is to propose a new motor which is economical to manufacture.

Another object of the invention is to propose a new engine whose operation is based on simple and proven mechanical principles.

Another object of the invention is to propose a new motor whose construction particularly limits the occurrence of undesirable vibratory and acoustic phenomena.

Another object of the invention is to propose a new motor implementing a minimum moving mass and likely to provide important intake and / or exhaust sections.

Another object of the invention is to propose a new engine that implements a minimum of different parts.

• un cylindre qui contribue à délimiter une chambre dont le volume varie entre une valeur minimale et une valeur maximale,
• un premier piston contribuant lui aussi à délimiter ladite chambre, lesdits premier piston et cylindre étant conçus pour subir un premier mouvement relatif de va-et-vient sous l'effet de la variation du volume de la chambre,
• un arbre de sortie rotatif,

ledit moteur comprenant en outre :

• un deuxième piston qui contribue également à délimiter le volume de ladite chambre, lesdits deuxième piston et cylindre étant conçus pour subir un deuxième mouvement relatif de va-et-vient sous l'effet de la variation du volume de la chambre, ledit arbre de sortie étant monté coaxialement auxdits premier et deuxième pistons,
• un premier moyen de conversion dudit premier mouvement relatif de va-et-vient en mouvement rotatif de l'arbre de sortie, comprenant d'une part un premier chemin de guidage sensiblement ondulé solidaire de l'un desdits trois composants et d'autre part un premier élément de guidage qui est conçu pour se déplacer le long dudit premier chemin de guidage et qui est solidaire d'un autre desdits trois composants,
• un premier organe de réglage de la position du premier chemin de guidage et/ou du premier élément de guidage relativement au(x) composant(s) dont il(s) est (sont) solidaire(s), pour régler la valeur minimale et/ou la valeur maximale du volume de la chambre.

The objects assigned to the invention are achieved by means of an engine comprising at least the following three components:

• a cylinder which contributes to delimit a chamber whose volume varies between a minimum value and a maximum value,
• a first piston also contributing to define said chamber, said first piston and cylinder being designed to undergo a first relative reciprocating movement under the effect of the variation of the volume of the chamber,
• a rotary output shaft,

said engine further comprising:

• a second piston which also contributes to defining the volume of said chamber, said second piston and cylinder being designed to undergo a second relative back-and-forth movement under the effect of the variation of the volume of the chamber, said output shaft being mounted coaxially with said first and second pistons,
• first conversion means of said first relative reciprocating movement in rotary motion of the output shaft, comprising on the one hand a first substantially corrugated guide path secured to one of said three components and secondly a first guide member which is adapted to move along said first guide path and which is integral with another one of said three components,
• a first member for adjusting the position of the first guide path and / or the first guide element relative to the component (s) of which it (they) is (are) integral, to set the minimum value and / or the maximum value of the volume of the chamber.

SUMMARY DESCRIPTION OF THE DRAWINGS

• La figure 1 est un schéma de principe, selon une vue de côté en coupe partielle, d'un exemple de moteur conforme à l'invention.
• La figure 2 illustre, selon une vue de côté en coupe partielle, un exemple de moteur à combustion selon l'invention, correspondant au principe constructif de la figure 1.
• La figure 3 illustre, selon une vue en perspective, le moteur de la figure 2 sans son cylindre.
• La figure 4 illustre, selon une vue en perspective, un détail de conception du moteur des figures 2 et 3.

Other objects and advantages of the invention will appear in more detail on reading the description which follows, with reference to the appended drawings, given purely by way of non-limiting illustration, in which:

• The figure 1 is a block diagram, according to a side view in partial section, of an exemplary motor according to the invention.
• The figure 2 illustrates, in a partial sectional side view, an example of a combustion engine according to the invention, corresponding to the constructive principle of the figure 1 .
• The figure 3 illustrates, in a perspective view, the engine of the figure 2 without his cylinder.
• The figure 4 illustrates, in a perspective view, a design detail of the engine of figures 2 and 3 .

BEST MODE OF REALIZING THE INVENTION

The invention relates to an engine, that is to say a device capable of providing a mechanical work usable in particular for propelling a vehicle, and for example a motor vehicle, a motorcycle, an aircraft or a boat, or for operating a machine (machine tool, public works machine, agricultural machine, pump, compressor) or an energy conversion device, such as a generator.

The engine 1 according to the invention preferably constitutes an internal combustion engine ("internal combustion engine "), that is to say a motor capable of to produce mechanical energy from the combustion therein of a working fluid containing a fuel, and for example a hydrocarbon-based fuel such as gasoline. The invention is however not limited to combustion engines and may relate to a motor whose operation is not based on the combustion of a fuel, as is the case for example with compressed air engines.

The engine 1 according to the invention comprises at least the following three components: a cylinder 2, a first piston 4 and a rotary output shaft 8.

The cylinder 2 contributes to delimit a chamber 3 whose volume varies between a minimum value and a maximum value. Advantageously and known per se, the volume of the chamber 3 varies cyclically during the operation of the engine 1, so that the volume of the chamber 3 passes alternately and continuously from its minimum value to its maximum value and vice versa.

In the case, illustrated in the figures, where the engine 1 is an internal combustion engine, the chamber 3 forms a combustion chamber designed to accommodate a working fluid intended to undergo combustion within said chamber 3. The working fluid is therefore in this case a combustible fluid and it is preferably formed of a gas consisting of a mixture of air and vaporized fuel. This gas is intended to undergo a rapid combustion, and more precisely an explosion (or even more precisely a deflagration), within the chamber 3. The fuel may for example consist of a petroleum derivative, it being understood that the invention is absolutely not limited to a specific working fluid. The variation of the volume of the chamber 3 is thus generated, in the example illustrated in the figures and as is well known per se, by the variation of the volume of the working fluid present in the chamber 3, under the effect of the combustion phenomenon (which causes a relaxation of the working fluid).

The cylinder 2 is for example, as illustrated in the figures, in the form of a hollow tube, preferably rectilinear, of longitudinal axis X-X 'extension. Advantageously, as illustrated in the figures, the cylinder 2 has a substantially circular section. It is however quite possible that the cylinder 2 has a non-circular section, and for example a polygonal section, without departing from the scope of the invention. The inner wall 20 of the cylinder 2 contributes to define, in the embodiment illustrated in the figures, the chamber 3. In the case where the engine 1 is an internal combustion engine (as in the example illustrated in the figures), and therefore that the chamber 3 forms a combustion chamber, the cylinder 2 is preferably made of a material having a high mechanical and thermal strength, such as for example a metal material of the cast iron or aluminum alloy type, so as to overcome the thermal and mechanical stresses resulting fuel combustion within the chamber 3.

• Configuration A : le cylindre 2 est fixe (immobile) tandis que le premier piston 4 est monté mobile relativement au cylindre 2 pour se déplacer selon un mouvement de va-et-vient (mouvement alternatif) par rapport audit cylindre 2.
• Configuration B : le premier piston 4 est fixe (immobile) tandis que le cylindre 2 est monté mobile relativement au premier piston 4 pour se déplacer selon un mouvement de va-et-vient (mouvement alternatif) par rapport audit premier piston 4.

The first piston 4 also contributes to defining the volume of the chamber 3, said first piston 4 and cylinder 2 being designed to undergo a first relative movement back and forth under the effect of the variation of the volume of the chamber 3 In other words, the invention provides in particular one or the other of the following constructive configurations:

• Configuration A: the cylinder 2 is stationary (stationary) while the first piston 4 is movably mounted relative to the cylinder 2 to move in a reciprocating (reciprocating) movement with respect to said cylinder 2.
• Configuration B: the first piston 4 is stationary (immobile) while the cylinder 2 is mounted movably relative to the first piston 4 to move in a reciprocating (reciprocating) movement with respect to said first piston 4.

In the preferred example illustrated in the figures, and which corresponds to the configuration A, the first piston 4 is designed to slide in the cylinder 2 in a reciprocating movement under the effect of the volume variation of the chamber 3. Thus, the first piston 4 is threaded inside the cylinder 2 and is tightly fitted against the inner wall 20 of the cylinder 2, so as to slide within the cylinder 2 along the axis X-X ', while remaining permanently in sealing contact with the inner wall 20 of said cylinder 2. The configuration A is very particularly preferred because it allows easy implementation of the engine 1, and is generally more reliable and easy to manufacture than the configuration B. realization of the sealed contact between the first piston 4 and the inner wall 20 of the cylinder 2 can be achieved by any means known to those skilled in the art, taking up and adapting for example the well known technical solutions and Proven implemented in the prior art.

The first piston 4 advantageously has a head 4A which contributes to delimit the chamber 3.

The head 4A preferably has a cross section which is complementary to the internal cross section of the cylinder 2, this section preferably being a circular section as in the examples illustrated in the figures. The first piston 4 further comprises a skirt 4B which extends from and to the periphery of the head 4A. Advantageously, the first piston 4 has a longitudinal axis of extension Y-Y ', which corresponds to the axis of symmetry of the cross section of the head 4A of said piston. The axis longitudinal YY 'of the first piston 4 is advantageously coincides with the extension axis XX' of the cylinder 2 when the first piston 4 is installed in a functional position inside the cylinder 2, as illustrated in FIG. figure 2 . According to the preferred embodiment illustrated in the figures, which corresponds to a sub-configuration A1 of the configuration A, the first piston 4 is designed to slide in the cylinder 2 in a pure axial translation movement, that is to say that said first piston 4 is guided relative to the cylinder 2 to be able to move in longitudinal translation, parallel to the axis X-X ', without rotation of the first piston 4 on itself. In other words, the first piston 4 is in this case mechanically linked to the cylinder 2 by a slide connection. Such axial guidance of the first piston 4 in pure translation in the cylinder 2 limits not only the problems of vibration and premature wear of the piston against the jacket encountered in the engines of the prior art, but also the problems of loss. of efforts encountered in these same engines. These problems essentially come from the fact that in the prior art, the pistons are not directly guided in the cylinder, but are indirectly through the linkage which works off-axis during the movements of the piston under load.

There are of course a multitude of technical possibilities, well known to those skilled in the art, for making such a sliding connection between the first piston 4 and the cylinder 2.

In the embodiment illustrated in the figures, this sliding connection, which allows the first piston 4 to slide in the cylinder 2 in a substantially pure rectilinear translational movement, is achieved by the cooperation of at least one slide 4C mounted on the first piston 4 and a corresponding slide 2A formed in the cylinder 2 and extending substantially parallel to the axis XX 'longitudinal extension of said cylinder 2. Preferably, in order to ensure a balanced guide of the first piston 4 relative to the cylinder 2, the first piston 4 is provided with two sliders arranged diametrically opposite on the piston relative to the axis YY 'of symmetry of this last. In order to improve the slide / slide contact, particularly in order to limit the friction which adversely affects the efficiency of the motor, each slide advantageously comprises a roller 40C rotatably mounted on an axis 400C itself mounted in an orifice formed through the skirt. 4B, so that said axis 400C extends substantially radially relative to the extension axis XX 'of the first piston 4. Each roller 40C is designed to roll in the corresponding slide 2A, which advantageously consists, as illustrated in the figures, in a rectilinear groove formed in the inner wall 20 of the cylinder 2, on the surface of said inner wall 20, facing the corresponding roller.

The invention is however absolutely not limited to the implementation of a first piston 4 mounted in a slide connection in the cylinder 2. It is for example quite possible without leaving the frame of the invention, the first piston 4 undergoes, during its movement back and forth, a rotation on itself about its axis YY ', so that the movement of the first piston 4 in the cylinder 2 is in this case not a pure axial translation movement but a helical translation movement (sub-configuration A2).

In the case of the configuration B, it is also possible to provide a rectilinear (sub-configuration B1) or rotary (sub-configuration B1) back-and-forth movement of the cylinder 2 relative to the first piston 4.

The various configurations envisaged in the foregoing are summarized in Table 1 below. <u> Table 1 </ u> Configuration Sub-configuration Cylinder movement Movement of the first piston AT A1 None (fixed cylinder) Straight back and forth A2 None (fixed cylinder) Rotary back and forth B B1 Straight back and forth None (fixed first piston) B2 Rotary back and forth None (fixed first piston)

The rotary output shaft 8 preferably has a rectilinear character and extends along a longitudinal axis Z-Z ', in which it is designed to rotate.

The output shaft 8 is preferably mounted coaxially with the first piston 4, so that the X-X ', Y-Y' and Z-Z 'axes are advantageously combined. Preferably and as illustrated in the figures, the output shaft 8 passes through the first piston 4, that is to say that said first piston 4 is threaded on the output shaft 8. For this purpose, the first piston 4 is provided with an orifice through which the output shaft 8 passes, the interface between the first piston 4 and the output shaft 8 preferably being sealed.

According to the invention, the engine 1 comprises a first conversion means of said first relative reciprocating movement in rotary motion of the output shaft 8, and more preferably in continuous rotary motion, in a single direction of rotation. , of the output shaft 8.

The first conversion means comprises on the one hand a substantially corrugated first guiding path 9 integral with one of said three components (cylinder 2, first piston 4 or output shaft 8) and on the other hand a first guiding element. 10 which is adapted to move along said first guide path 9 and which is integral with another of said three components. The invention thus relates to several constructive variants, the main ones are summarized in Table 2 below. <u> Table 2 </ u> Sub - configuration of the invention (see Table 1) Variant of the invention Component with which the first guide path is secured Component with which the first guide element is secured A1 A11 Output tree First piston A1 AT 12 First piston Output tree A2 A21 Cylinder First piston A2 A22 First piston Cylinder B1 B11 Cylinder Output tree B1 B12 Output tree Cylinder B2 B21 Cylinder First piston B2 B22 First piston Cylinder

Preferably, the cooperation between the first guide path 9 and the first guide element 10 is reciprocal, that is to say that it not only makes it possible to convert the relative movement of reciprocating piston 4 / 2 cylinder in rotary motion of the output shaft 8, but also to convert the rotary motion of the output shaft 8 in relative motion of reciprocating piston 4 / cylinder 2.

The example illustrated in the figures corresponds to variant A11 of Table 2 above. In this variant, the output shaft 8 is fitly fitted into the central orifice formed through the first piston 4 to allow the latter to slide along the output shaft 8 while remaining in sealing contact with said output shaft 8, and thus avoid any communication between the inside of the chamber 3 and the outside through the interface between the output shaft 8 and the first piston 4. The first path guide 9 is integral with the output shaft, while the first guide element 10 is integral with the first piston 4.

• les variations de pression au sein de la chambre 3, obtenues par des cycles de déflagration d'un mélange détonant (du type mélange air/carburant vaporisé), entraînent un mouvement alternatif rectiligne du premier piston 4, qui se déplace en translation pure,
• le premier piston 4 entraîne lui-même en rotation l'arbre de sortie 8, lequel constitue l'arbre moteur destiné à être raccordé à l'objet à entraîner, par exemple aux roues d'un véhicule automobile.

The variant A11 of the engine 1 according to the invention illustrated in the figures operates according to the following general principle:

• the pressure variations within the chamber 3, obtained by detonation blast cycles (of the vaporized air / fuel mixture type), cause a rectilinear reciprocating movement of the first piston 4, which moves in pure translation,
• the first piston 4 itself drives in rotation the output shaft 8, which constitutes the drive shaft intended to be connected to the object to be driven, for example to the wheels of a motor vehicle.

Such a design avoids the implementation of force references according to different working axes, as in the prior art, and allows on the contrary a direct transmission of the action of the first piston 4 on the output shaft 8. In in other words, the first piston 4 directly drives the output shaft 8 in rotation, which gives the engine 1 a particularly compact character, the latter can thus be easily integrated into the chassis of a vehicle. Such a design is also likely to improve the center of gravity of the vehicle due to the essentially longitudinal nature of the engine 1, which allows the positioning of said engine 1 along the axis of symmetry of said vehicle. Thanks to the direct and coaxial drive of the output shaft 8 by the first piston 4, the torsional effects to which the output shaft 8 is subjected are largely minimized with respect to those imparted to the crankshafts by the connecting rods of the engines. the prior art.

Advantageously, the first guide path 9 has a substantially sinusoidal shape. More precisely, in the example illustrated in the figures, the first guide path 9 extends along an annular profile around the longitudinal extension axis Z-Z'-of the output shaft 8.

Preferably, the first guide path 9 comprises a first groove while the first guide member 10 comprises a first finger which protrudes from the first piston 4 and engages in said first groove. Preferably, the first guide member 10 comprises two fingers arranged diametrically opposite relative to the Y-axis Y 'and engaging the same first groove. In order to improve the contact between the first guide element 10 and the first groove, the first finger advantageously comprises a roller 10A rotatably mounted on an axis itself mounted in an orifice formed through the skirt 4B, so that that said axis extends substantially radially with respect to the extension axis XX 'of the piston 4. Preferably, the axis in question corresponds to the axis 400C on which the roller 40C is mounted. In this particularly simple and reliable embodiment, the roller 10A is mounted on the axis 400C, inside the skirt 4B, to engage the corresponding sinusoidal groove, while the roller 40C is mounted on the same axis 400C, outside the skirt 4B, to engage the corresponding rectilinear groove 2A. According to the invention, the motor 1 further comprises a first member 5 for adjusting the position of the first guide path 9 and / or the first guide element 10 relative ai (x) component (s) which he (they) is (are) integral (s), to set the minimum value and / or the maximum value of the volume of the chamber 3.

The invention therefore relates in particular to the alternative sub-variants mentioned in Table 3 below. <u> Table 3 </ u> Variant (see Table 2) Sub - variant Medium (s) whose position is adjusted by the adjusting member 5 Value (s) of chamber volume set by regulator 5 A11 A111 First guide path Minimum and maximum values A11 A112 First guide path Minimum value A11 A113 First guide path Maximum value A11 A114 First guide element Minimum and maximum values A11 A115 First guide element Minimum value A11 A116 First guide element Maximum value A11 A117 First path and guide element Minimum and maximum values A11 A118 First path and guide element Minimum value A11 A119 First path and guide element Maximum value AT 12 A121 First guide path Minimum and maximum values AT 12 A122 First guide path Minimum value AT 12 A123 First guide path Maximum value AT 12 A124 First element of quidage Minimum and maximum values AT 12 A125 First guide element Minimum value AT 12 A126 First guide element Maximum value AT 12 A127 First path and guide element Minimum and maximum values AT 12 A128 First way and quidage element Minimum value AT 12 A129 First path and guide element Maximum value A21 A211 First guide path Minimum and maximum values A21 A212 First guide path Minimum value A21 A213 First guide path Maximum value A21 A214 First guide element Minimum and maximum values A21 A215 First guide element Minimum value A21 A216 First guide element Maximum value A21 A217 First path and guide element Minimum and maximum values A21 A218 First path and guide element Minimum value A21 A219 First path and guide element Maximum value A22 A221 First guide path Minimum and maximum values A22 A222 First guide path Minimum value A22 A223 First guide path Maximum value A22 A224 First guide element Minimum and maximum values A22 A225 First guide element Minimum value A22 A226 First guide element Maximum value A22 A227 First path and guide element Minimum and maximum values A22 A228 First path and guide element Minimum value A22 A229 First path and guide element Maximum value B11 B111 First guide path Minimum and maximum values B11 B112 First guide path Minimum value B11 B113 First guide path Maximum value B11 B114 First guide element Minimum and maximum values B11 B115 First guide element Minimum value B11 B116 First guide element Maximum value B11 B117 First path and guide element Minimum and maximum values B11 B118 First path and guide element Minimum value B11 B119 First path and guide element Maximum value B12 B121 First guide path Minimum and maximum values B12 B122 First guide path Minimum value B12 B123 First guide path Maximum value B12 B124 First guide element Minimum and maximum values B12 B125 - First guide element Minimum value B12 B126 First guide element Maximum value B12 B127 First path and guide element Minimum and maximum values B12 B128 First path and guide element Minimum value B12 B129 First path and guide element Maximum value B21 B211 First guide path Minimum and maximum values B21 B212 First guide path Minimum value B21 B213 First guide path Maximum value B21 B214 First guide element Minimum and maximum values B21 B215 First guide element Minimum value B21 B216 First guide element Maximum value B21 B217 First path and guide element Minimum and maximum values B21 B218 First path and guide element Minimum value B21 B219 First path and guide element Maximum value B22 B221 First guide path Minimum and maximum values B22 B222 First guide path Minimum value B22 B223 First guide path Maximum value B22 B224 First guiding guide element Minimum and maximum values B22 B225 First guide element Minimum value B22 B226 First guide element Maximum value B22 B227 First path and guide element Minimum and maximum values B22 B228 First path and guide element Minimal steam 822 B229 First path and guide element Maximum value

The invention is thus based on the idea of adjusting the position of the guide path 9 and / or the guide element 10 to adjust the volume of the chamber 3, which allows to adjust in particular the compression ratio. In this way, the invention makes it possible to obtain a variable compression ratio motor 1 of particularly simple, compact and reliable construction. In particular, acting directly on the position of the guide path 9 and / or the guide element 10 proves to be a particularly simple and effective technical measure for accurately adjusting the compression ratio, even during operation. of the engine 1.

The exemplary embodiment illustrated in the figures corresponds to the subvariant A111 (see Table 3 above). According to this sub-variant, the first-setting member 5 is designed to adjust the position of the first path of 9 relative to the output shaft 8, which means that the first guide path is movable relative to said output shaft 8, while being attached thereto to transmit to the shaft 8 the movement (converted) of the first piston 4.

According to this sub-variant A111, the guide element 10 is in turn fixed in position relative to the component that carries it, namely the first piston 4. According to the sub-variant A111, the adjustment member 5, allowing to adjust the position of the first guide path 9 relative to the output shaft 8, makes it possible to set both the minimum value and the maximum value of the volume of the chamber 3. Indeed, in this sub-variant A111, the first piston 4 performs a back-and-forth movement of predetermined amplitude (imparted by the shape of the guide path 9) around a median position. The adjustment member 5 is designed in this case to move this median position, which amounts to shift the alternating stroke of the first piston 4 and thus to simultaneously change the minimum value and the maximum value of the volume of the chamber 3. L However, the invention is not limited to such a mode of operation and it is quite possible that the adjustment member 5 acts only on the maximum value or on the minimum value of the volume of the chamber 3, by example by operating in a timely manner a displacement of the guide path 9 and / or the guide element 10) to maintain the minimum value or the constant maximum value.

In the embodiment illustrated in the figures (which corresponds to the subvariant A111), the first adjustment member 5 advantageously comprises a first adjustment piece 6 (illustrated alone on FIG. figure 4 ) slidably mounted on and along the output shaft 8, said first part 6 carrying the first guide path 9. The first guide piece 6 is advantageously in the form of a sleeve 6A which extends longitudinally along an axis W-W '. Said sleeve 6A is threaded on the output shaft 8, coaxially with the latter, so that the axes X-X ', Y-Y', ZZ 'and WW' are substantially merged. Preferably, the sleeve 6A is guided in a pure axial translation movement on the output shaft 8, that is to say that the output shaft 8 and the sleeve 6A are connected by a mechanical link of the slide type. For this purpose, the sleeve 6A is for example provided with an oblong hole 7, which is intended to cooperate with a pin 17 fixed directly on the output shaft 8 and protruding radially from the latter. The pin 17 is received in the oblong hole 7, so that the cooperation between the pin 17 and the oblong hole 7 provides a guide in translation of the sleeve 6A on the output shaft 8. The sleeve 6A can thus slide on the output shaft 8, in a race whose amplitude corresponds to the length of the oblong hole 7. The length of the oblong hole 7 is in turn determined with respect to the desired adjustment range of the minimum and maximum values of the volume of the room 3.

According to the advantageous embodiment illustrated in the figures (sub-variant A111), the first adjustment member 5 comprises firstly a threaded well 18 which is fixed to the cylinder 2 and which is coaxial with the output shaft 8 and on the other hand a threaded tube 19 attached at a first end thereof to the first adjusting member 6, said threaded tube 19 being capable of being screwed and unscrewed into the threaded well 18 to vary the position of the first piece 6 relative to the output shaft 8, which is fixedly mounted relative to the cylinder 2. More specifically, the threaded tube 19 is threaded coaxially on the output shaft 8, so as to freely rotate relative thereto around of the Y-Y 'axis. To this end, the tube 19 is preferably provided, towards its end attached to the first adjusting member 6, a needle stop 19A which provides the connection between the threaded tube 19 and the sleeve 6A. In order to control the screwing / unscrewing of tube 19 in the well 18, the second end of the threaded tube 19, opposite the first end attached to the sleeve 6, is provided with a gear 19B for driving in rotation of the threaded tube 19. This toothed wheel 19B is it - Even designed to be rotated by a control system (not shown in the figures) mechanical and / or electrical. The control system may for example comprise an electric motor provided with a pinion which meshes with the toothed wheel 19B. Alternatively, the control system can draw its motive power directly from the output shaft 8. In a particularly interesting embodiment, the engine 1 comprises a management module of the control system of the gear wheel 19B, said management module being preferably designed to automatically adjust, continuously and permanently the compression ratio (by setting the minimum and / or maximum values of the volume of the chamber 3) as a function of the stresses and / or the speed of the engine 1, to optimize in particular the torque, the speed and the efficiency of the engine 1. The management module preferably comprises for this purpose sensors that collect information on the instantaneous operation of the engine 1 and a computer (microprocessor) that processes this information to provide to the control system an order of rotation of the toothed wheel19B in one direction or the other, to change the position of the travel path guidance 9 and thus the compression ratio of the engine 1. The computer can thus be programmed to greatly increase the compression ratio at the beginning of acceleration, so that the engine 1 provides a high torque, then reduce the rate of compression. compression to regain torque at high speed.

Advantageously, the engine 1 according to the invention comprises a second piston 14 which also contributes to defining the volume of the chamber 3, said second piston 14 and cylinder 2 being designed to undergo a second relative movement back and forth under the effect of the variation of the volume of the chamber 3. Preferably and as illustrated in the figures, the engine 1 thus comprises in this case a cylinder 2 in which the first and the second piston 4, 14 are mounted to slide axially. In this particularly advantageous embodiment, which is illustrated in the figures, the chamber 3 is preferably formed by the interstitial space separating the first and the second piston 4, 14 in the cylinder 2.

In other words, the chamber 3 corresponds in this case to the free space of variable volume located inside the cylinder 2, between the pistons 4, 14. Advantageously, as illustrated in the figures, the first and second pistons 4 , 14 are mounted in opposition within the cylinder 2, that is to say so that their respective heads 4A, 14A face each other. The chamber 3 thus extends in the space delimited axially by the heads 4A, 14A of the first and second pistons 4, 14 and radially by the internal wall 20 of the cylinder 2 extending between said heads 4A, 14A of said pistons 4, 14. The chamber 3 thus has a variable volume which depends on the relative position of the first and second piston 4, 14. Advantageously and as illustrated in the figures, the first piston 4 and the second piston 14 are designed to move according to movements counter-movement in the cylinder (which is in this case fixed), so that said pistons 4, 14 move toward and away from each other substantially simultaneously (the first and second movements back and forth are opposed). In other words, the first piston 4 and the second piston 14 move symmetrically with respect to the median plane of the chamber 3, perpendicular to the axis X-X '. In the preferred embodiment illustrated in the figures, each piston 4, 14 is designed to move in the cylinder 2 individually, that is to say independently of the other piston 14, 4. Preferably, the second piston 14 is identical to the first piston 4 and it is also mounted in the motor 1 identically to said first piston 4. In this advantageous embodiment, which is illustrated in the figures, the output shaft 8 is also mounted coaxially with the second piston 14, the output shaft 8 and the second piston 14 cooperating to convert the movement of the second piston 14 into rotary movement of the output shaft 8. For this purpose, the engine 1 comprises a second conversion means of said second relative movement of va-and - comes in rotary motion from the output shaft 8.

Said second conversion means comprises on the one hand a second substantially corrugated guide path 15 integral with one of the following three elements: cylinder 2, output shaft 8 and second piston 14 and secondly a second guide element 16 which is adapted to move along said second guide path 15 and which is integral with another of said three elements. Advantageously, said motor 1 further comprises a second adjustment member 50 for the position of the second guide path 15 and / or the second guide element 16 relative to the element (s) of which it (s) is (are) integral, to set the minimum value and / or the maximum value of the volume of the chamber 3. In the particularly advantageous embodiment illustrated in the figures, the motor 1 has an overall symmetry even compared to the median plane of the chamber 3, c that is to say the plane passing through the center of the chamber 3 and which is perpendicular to the axis XX 'of longitudinal extension of the cylinder 2.

• une chambre 3 délimitée par deux pistons 4, 14 travaillant de préférence en opposition et de concert pour convertir leurs mouvements de va-et-vient opposés en un mouvement rotatif continu de l'arbre de sortie 8,
• et des premier et de préférence deuxième moyens de réglage 5, 50 permettant d'agir sur le volume disponible de la chambre 3, et donc sur le taux de compression.

This means that all the construction arrangements relating to the second piston 14, the second guide path 15, the second guide member 16 and the second adjustment member 50 are identical to those respectively relating to the first piston 4, the first path 9, the first guide element 10 and the first adjustment member 5. It is particularly interesting to combine:

• a chamber 3 delimited by two pistons 4, 14 preferably working in opposition and in concert to convert their opposite back and forth movements into a continuous rotary movement of the output shaft 8,
• and first and preferably second adjustment means 5, 50 for acting on the available volume of the chamber 3, and thus on the compression ratio.

Indeed, the presence of two pistons with adjustable stroke allows to finely control the compression ratio, acting separately on the pistons 4, 14 to adjust the compression ratio.

The use of two pistons 4, 14 to define the same chamber 3 also allows, by acting symmetrically on the pistons 4, 14, to benefit from a large amplitude variation of compression ratio without imparting a significant displacement piston stroke, since each piston contributes half to the variation of the compression ratio.

The invention also relates as such to a vehicle, of the motor vehicle type, equipped with a motor 1 according to the invention.

POSSIBILITY OF INDUSTRIAL APPLICATION

The invention finds its industrial application in the design, manufacture and use of motors.

Claims (11)

1. An engine (1) comprising at least the following three components:

   - a cylinder (2) which contributes to delimiting a chamber (3) whose volume varies between a minimum value and a maximum value,

   - a first piston (4) also contributing to delimiting said chamber (3), said first piston (4) and cylinder (2) being designed to undergo a first relative reciprocating movement under the effect of the variation of the volume of the chamber (3),

   - a rotary output shaft (8),

   said engine (1) also comprising:

   - a second piston (14) which also contributes to delimiting the volume of said chamber (3), said second piston (4) and cylinder (2) being designed to undergo a second relative reciprocating movement under the effect of the variation of the volume of the chamber (3), said output shaft (8) being mounted coaxially to said first and second pistons (4, 14),

   - a first means (5) of converting said first relative reciprocating movement into rotary movement of the output shaft (8), comprising, on the one hand, a first guidance path (9) of substantially undulating form joined to one of said three components (2, 4, 8) and, on the other hand, a first guidance element (10) which is designed to be displaced along said first guidance path (9) and which is joined to another of said three components (2, 4, 8),

   - a first member (5) for adjusting the position of the first guidance path (9) and/or of the first guidance element (10) relative to the component(s) (2, 4, 8) to which it (they) is (are) joined, to adjust the minimum value and/or the maximum value of the volume of the chamber (3).
2. The engine (1) as claimed in claim 1, characterized in that the first guidance path (9) is joined to the output shaft (8), whereas the first guidance element (10) is joined to the first piston (4).
3. The engine (1) as claimed in one of the preceding claims, characterized in that the first guidance path (9) comprises a first groove, whereas the first guidance element comprises a first finger which engages in said first groove.
4. The engine (1) as claimed in one of the preceding claims, characterized in that the first adjustment member (5) comprises a first adjustment part (6) mounted to slide over and along the output shaft (8), said first adjustment part (6) bearing the first guidance path (9).
5. The engine (1) as claimed in claim 4, characterized in that the first adjustment member (5) comprises, on the one hand, a threaded well (18) which is fixed to the cylinder (2) and which is coaxial to the output shaft (8) and, on the other hand, a threaded tube (19) attached at a first of its ends to the first adjustment part (6), said threaded tube (19) being capable of being screwed and unscrewed in the threaded well (18) to vary the position of the first adjustment part (6) relative to the output shaft (8), which is mounted fixedly relative to the cylinder (2).
6. The engine (1) as claimed in claim 5, characterized in that the second end of the threaded tube (19) is provided with a toothed wheel (19B) in order to drive the threaded tube (19) in rotation.
7. The engine (1) as claimed in one of claims 1 to 6, characterized in that said chamber (3) is formed by the interstitial space separating said first and second pistons (4, 14) in the cylinder (2).
8. The engine (1) as claimed in one of claims 1 to 7, characterized in that the first and second reciprocating movements are opposite, such that said first and second pistons (4, 14) move toward one another and away from one another substantially simultaneously.
9. The engine (1) as claimed in one of claims 1 to 8, characterized in that it comprises a second means of converting said second relative reciprocating movement into rotary movement of the output shaft (8), said second conversion means comprising, on the one hand, a second guidance path (15) of substantially undulating form joined to one of the following three elements: cylinder (2), output shaft (8) and second piston (14) and, on the other hand, a second guidance element (16) which is designed to be displaced along said second guidance path (15) and which is joined to another of said three elements (2, 8, 14), said engine (1) also comprising a second member (50) for adjusting the position of the second guidance path (15) and/or of the second guidance element (16) relative to the element (s) (2, 8, 14) to which it (they) is (are) joined, to adjust the minimum value and/or the maximum value of the volume of the chamber (3).
10. The engine (1) as claimed in one of claims 1 to 9, characterized in that it constitutes an internal combustion engine, said chamber (3) being designed to accommodate a working fluid intended to undergo a combustion within said chamber (3).
11. A vehicle equipped with an engine (1) conforming to one of the preceding claims.

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