EP1939424B1 - Internal combustion engine with variable swept volume and/or variable compression ratio with a swing follower between the crankshaft and the connecting rod - Google Patents

Abstract

The engine has a cylinder (10) in which a piston (14) slides between a top dead center and a bottom dead center under an action of a connecting rod (20). A crankshaft (38) controls displacement of the piston under an effect of a cam follower (26) to vary a swept volume and a compression ratio of the engine. The cam follower is pivotingly mounted around an articulation axle (46) and displaced in translation along a direction. The cam follower is connected to the connecting rod and to the crankshaft respectively by two ends (24, 28) of the follower. An independent claim is also included for a method for varying a swept volume and a compression ratio.

Description

The present invention relates to an internal combustion engine with variable compression ratio and / or variable displacement.

It concerns engines with direct or indirect fuel injection, particularly of the Diesel or Gasoline type with or without controlled ignition.

As is widely known by those skilled in the art, it is useful to be able to vary the compression ratio and / or the displacement of an engine according to its conditions of use.

In the case of a variation of the compression ratio, it makes it possible to increase the efficiency of the engine, especially at low speed and at low load, or to prevent the occurrence of rattling which can be a destructive phenomenon of the engine . Generally the compression ratio of an engine is defined as the ratio between the volume formed by the dead volume of the combustion chamber added to that swept by the piston between its bottom dead center (LDC) and its top dead center (TDC). and the dead volume of this room.

The change in displacement makes it possible to modify the quantity of air admitted to the combustion chamber and consequently to use the engine at high loads over a large part of its range of use. The displacement of a motor is considered as the volume swept by the piston between its position of bottom dead center (PMB) and its position of high point (PMH).

As best described in the application French Patent No. 2,807,105 it is known to use devices which make it possible to vary the compression ratio by varying the volume of the combustion chamber to the point where dead top of the piston, this volume being more commonly referred to as dead volume.

These devices generally comprise a connecting rod whose small end is connected to an axis of a sliding piston in the engine cylinder and whose connecting rod head is connected to a hinge with one end of a rod used to vary the distance. between the axis of the piston and the axis of the crankpin which controls the displacement of the piston in a rectilinear reciprocating movement within the cylinder. This link comprises a body carrying an axis of articulation with the crankpin and another end subjected to the action of a control means which controls the tilting of this link about the axis of the crankpin. The tilting makes it possible to modify the inclination of the body of this link relative to its longitudinal axis and thus to modify the distance between the axis of the piston and the axis of the crankshaft.

Other variations devices, such as those better described in the documents GB 2,312,242 , US 4,917,066 , EP 0 248 655 , GB 228,706 , US 926,564 or US 680,337 comprise an articulated connection system with a rocker pivoting about an axis of articulation and movable in translation in one direction by displacement control means. This rocker comprises a light inside which is housed this axis of articulation and is connected by one of its ends to the connecting rod and the other of its ends to a connecting rod connected to the crankshaft.

One of the major disadvantages of these devices is to require the use of high power control means to allow the variation of length of the connecting rod.

In addition, these devices of the prior art do not allow to easily and surely change the compression ratio without changing the cubic capacity.

In addition, the position of the hinge pin in the lumen is difficult to determine depending on the desired variation.

The present invention proposes to overcome the drawbacks mentioned above by means of a device of simple design and easy to use.

For this purpose, the present invention relates to an internal combustion engine comprising at least one cylinder in which a piston slides between a top dead center and a bottom dead center under the action of a rod of axis XX and a crankshaft controlling in displacing said piston under the effect of an articulated connection system making it possible to vary the engine displacement and / or the compression ratio of the engine, said articulated connection system comprising a rocker pivotally mounted about an articulation axis and displaceable in translation in at least one direction by displacement control means, said rocker comprising a light inside which said shaft is housed and being connected at one of its ends to said connecting rod and at the other end thereof a link connected to said crankshaft, and a slide bearing the hinge pin and cooperating with the light of said rocker, characterized in that the rocker carries rainu inclined res cooperating with projections carried by the axis of articulation and through the slider through slots and in that the axis of articulation carries end faces on which is applied a force to obtain the displacement of said axis .

The displacement control means may comprise an eccentric bearing a bore for receiving the hinge axis.

The displacement control means may comprise two eccentrics arranged in parallel with each other and between which is placed the rocker with its axis of articulation.

The eccentric may carry a control means for rotation about its axis.

Preferably, the control means may comprise an axial bar.

The longitudinal axis of the connecting rod and the longitudinal axis of the rocker can form between them a non-zero angle.

• les figures 1 à 15 qui illustrent un moteur à combustion interne à taux de compression variable et/ou à cylindrée variable non couvert par la présente invention et parmi lesquelles :
  • la figure 1 est un schéma montrant un moteur dans une configuration moyenne nominale de cylindrée ;
  • les figures 2 et 3 sont des schémas illustrant le moteur de la figure 1 avec une position du piston au point mort haut et point mort bas respectivement ;
  • la figure 4 est un schéma montrant un moteur de la figure 1 dans une configuration moyenne de réduction de cylindrée ;
  • les figures 5 et 6 sont des schémas illustrant le moteur de la figure 4 avec une position du piston respectivement au point mort haut et point mort bas ;
  • la figure 7 est un schéma montrant un moteur de la figure 1 dans une configuration moyenne d'augmentation de cylindrée ;
  • les figures 8 et 9 sont également des schémas illustrant le moteur de la figure 7 avec une position du piston au point mort haut et point mort bas ;
  • la figure 10 est une vue schématique montrant un moteur pour une configuration moyenne initiale de taux de compression ;
  • la figure 11 est une vue schématique montrant le moteur de la figure 10 dans une configuration d'augmentation de taux de compression ;
  • la figure 12 est aussi une vue schématique montrant le moteur de la figure 10 pour une configuration de réduction de taux de compression ;
  • la figure 13 montre un schéma du moteur dans une configuration initiale pour aussi bien une variation de la cylindrée qu'une variation du taux de compression ;
  • la figure 14 montre le moteur de la figure 13 pour une augmentation du taux de compression ;
  • la figure 15 est un schéma du moteur de la figure 13 avec une augmentation du taux de compression et une réduction de la cylindrée ;
  • la figure 16 qui est une vue éclatée montrant un exemple de réalisation de l'un des éléments du moteur à combustion interne à taux de compression variable et/ou à cylindrée variable selon invention ;
  • la figure 17 qui est une vue frontale partielle de l'élément de la figure 16 ;
  • la figure 18 qui est une vue en coupe partielle d'une partie des éléments du moteur de l'invention comme schématisé à la figure 13 et
  • la figure 19 qui est une vue partielle en perspective de constituants de l'élément de la figure 18.

The other features and advantages of the invention will now appear on reading the following description, given solely by way of illustration and not limitation, and to which are appended:

• the Figures 1 to 15 which illustrate an internal combustion engine with variable compression ratio and / or variable displacement not covered by the present invention and among which:
  • the figure 1 is a diagram showing an engine in a nominal average displacement configuration;
  • the Figures 2 and 3 are diagrams illustrating the driving force of the figure 1 with a piston position at top dead center and bottom dead center respectively;
  • the figure 4 is a diagram showing a motor of the figure 1 in a medium displacement reduction configuration;
  • the Figures 5 and 6 are diagrams illustrating the driving force of the figure 4 with a position of the piston respectively at top dead center and bottom dead center;
  • the figure 7 is a diagram showing a motor of the figure 1 in an average configuration of displacement increase;
  • the Figures 8 and 9 are also diagrams illustrating the driving force of the figure 7 with a piston position at top dead center and bottom dead center;
  • the figure 10 is a schematic view showing a motor for an initial average compression ratio configuration;
  • the figure 11 is a schematic view showing the motor of the figure 10 in a compression rate increase configuration;
  • the figure 12 is also a schematic view showing the engine of the figure 10 for a compression rate reduction configuration;
  • the figure 13 shows a diagram of the engine in an initial configuration for a variation of the displacement as well as a variation of the compression ratio;
  • the figure 14 shows the engine of the figure 13 for an increase in the compression ratio;
  • the figure 15 is a diagram of the engine of the figure 13 with an increase in the compression ratio and a reduction in displacement;
  • the figure 16 which is an exploded view showing an exemplary embodiment of one of the elements of the internal combustion engine variable compression ratio and / or variable displacement according to the invention;
  • the figure 17 which is a partial frontal view of the element of the figure 16 ;
  • the figure 18 which is a partial sectional view of a part of the motor elements of the invention as shown schematically in FIG. figure 13 and
  • the figure 19 which is a partial perspective view of constituents of the element of the figure 18 .

We are now talking about Figures 1 to 3 which show an internal combustion engine which comprises at least one cylinder 10 closed in the upper part by a cylinder head 12. Inside this cylinder is placed a piston 14 for delimiting a combustion chamber 16 formed by the side wall of the cylinder , the cylinder head and the upper part of the piston. This piston is slidable, in a reciprocating rectilinear motion, inside the cylinder between a high position, known as High Dead Point (TDC), where it is closest to the cylinder head delimiting a dead volume C0 in this chamber. ( figure 2 ) and a low position, called Low Dead Point (PMB), where it is farthest from this cylinder head forming an active volume C1 in said chamber ( figure 3 ).

The piston is connected by an articulated piston pin 18 to a base of a connecting rod 20 whose head 22 is connected by a hinge pin 23 to the end 24 of a rod 26 which will be called a rocker in the sequence of the description. This rocker comprises another end 28 which is hingedly connected to an axis 30 carried by one end of a link 32 whose other end 34 is articulated on the crankpin 36 of a crank, such as the crankshaft 38 that usually includes any engine.

Thus, the rocker in association with the rod forms a linkage system articulated between the connecting rod and the crankshaft.

It should be noted that the general axis XX of the piston passing through the piston pin 18 and the small end pin 22 and the general axis YY of the rocker passing through the axes of the ends 24 and 28 of the rocker form between they have a non-zero angle so as to ensure proper operation of the assembly and to minimize the forces between the piston and the cylinder wall. Similarly, the longitudinal axis of the link 32 forms a non-zero angle with the axis YY of the rocker.

The rocker comprises between its two ends a bearing body 40 which comprises, preferably in its central region, a longitudinal slot 44 extending between the two ends of the rocker over a distance D and passing through the thickness of said body 40. Inside of this light is housed a hinge axis or pivot 46 of axis ZZ substantially perpendicular to the axis YY and which is fixedly connected to a fixed portion of the motor 50, as the housing block. The rocker is caused to move linearly along the axis YY, that is to say in a horizontal movement with reference to the figure 1 under the influence of any control means known to those skilled in the art. By way of non-limiting example, as illustrated in the figures, these means 52 comprise a horizontal jack 54 whose jack rod 56 is connected by any known means to the body 40 of the rocker without interfering with the pivoting of the rocker around of the pivot.

Preferably, but not mandatory, there are provided locking means 58 between the pivot 46 and the light 44 so as to immobilize this pivot in the light in a desired position. These means can be of all types within the reach of those skilled in the art as a pin through both the longitudinal walls of the light and the pivot.

When operating the engine, in a nominal average position as illustrated in figure 1 the piston 14 is in a median position between its PMH and its PMB and the crankshaft pin 36 is also in a median location between its 0 ° position and its 180 ° position. The pivot 46 is in a median position (D / 2) inside the aperture 44 while being immobilized by the locking means 58. This position of the pivot thus makes it possible to delimit two lever arms on the rocker, an arm a lever 26a of extension L1 between the axis of articulation of the end 24 of the rocker and the axis ZZ of the pivot 46 and another lever arm 26b of length L2 between this pivot axis and the axis of articulation of the other end 28 of this rocker.

Under the impetus of the rotation of the crankshaft 38 as indicated by the arrow R, the crankpin 36 passes from the middle position of the figure 1 to that indicated 180 ° of the figure 2 which corresponds substantially to the PMH of the piston 14. In this configuration, the rocker 26 has rotated about the pivot 46 in a clockwise direction under the impulse of the rod 32 and has driven via the rod 20 the piston 14 to its PMH leaving a dead volume C0 in the combustion chamber 16.

Continuing its rotation, always in the direction of the arrow R indicated in the figures, the crankshaft 38 drives the crank pin 36 from its 180 ° position to its 0 ° position, as indicated on the figure 3 . During this movement and from the configuration illustrated in the figure 2 , the rod 32 causes the tilting of the rocker in a counterclockwise direction about the pivot 46 to arrive at the position of this rocker illustrated on the figure 3 . During this movement of the rocker, it takes, through the rod 20, the piston 14 in a downward movement from the TDC illustrated in FIG. figure 2 up to its PMB by creating an active volume C1 in the combustion chamber 16.

Thus, the nominal cylinder capacity Cn of this engine is the difference between the active volume C1 and the dead volume C0 (Cn = C1-C0). Of course, to obtain the displacement of a multi-cylinder engine, the nominal capacity will be multiplied by the total number of cylinders.

In the case where it is desired to reduce the nominal engine displacement ( Figures 4 to 6 ) and from the nominal position illustrated in figure 1 where the tilter is in substantially horizontal position, the pivot 46 is unlocked from the light 44 by the means 58, the actuator is actuated so that its rod 56 is to translate, in a substantially horizontal rectilinear movement, the rocker 26 to the right of the figure 4 . At the end of this translational movement, the pivot is located at the end of the light closest to the cylinder by causing a modification of the lever arm of the rocker without changing the orientation of the rocker. So, as indicated on the figure 4 the lever arm 26'a has an extent L1 smaller than the extent L1 of the figure 1 and the lever arm 26'ba an extent 2 greater than the extent L2. Once this position is reached, the pivot is immobilized in the light by the locking means 58.

During the movement of the crankshaft 38 in a clockwise direction from its median position of the figure 4 up to its 180 ° position of the crankpin 36 of the figure 5 the link 32 controls the rocker 26 to pivot about the pivot 46 in a clockwise motion. Under the effect of this tilting, the piston 14 reaches its PMH ( Figure 5 ) leaving in the combustion chamber a dead volume C'0 greater than the volume C0, given essentially that the lever arm 26'a is smaller than the lever arm 26a.

When continuing the movement of the crank pin from its 180 ° position to its 0 ° position of the figure 6 , the rocker 26 pivots, from the configuration of the figure 5 around the pivot 46 in a counterclockwise direction by driving the piston 14 towards its PMB, leaving in the chamber 16 a volume C'1 smaller than the volume C1 of the figure 3 . Likewise, this reduction in the active volume C'1 comes from the fact that the lever arm 26'a is smaller than the lever arm 26a.

Thanks to this, the reduced displacement (Cr) corresponds to the difference between C'1 and C'0 (Cr = C'1-C'0) and this displacement is much lower than the nominal displacement of Figures 1 to 3 .

When, on the contrary, it is desired to increase the engine displacement, it is sufficient to control the displacement of the rocker 26 in a direction opposite to that of the figure 4 in order to increase the lever arm 26 "a and to decrease the lever arm 26" b ( Figures 7 to 9 ).

For this, the jack 54 controls the rod 56 so that it moves in horizontal translation the rocker to the left of the figure 7 until this pivot is positioned at the end of the light 44 furthest from the cylinder. This position of the pivot causes a modification of the lever arms of the rocker ( Figure 7 ) with an extension "L" 1 of the lever arm 26 "has greater than that L1 of the figure 1 and an extension L "2 of the lever arm 26" b smaller than the extension L2 of the figure 1 . Once this position is reached, the pivot is immobilized in this position with respect to the light thanks to the locking means 58.

During the movement of the crankshaft to the 180 ° position of the crankpin 36 from the middle position of the crankshaft figure 7 , the rocker 26 rotates about the pivot 46 in a clockwise direction under the action of the rod 32. Under the impulse of the rod 20, the piston 14 is brought to its TDC ( figure 8 ) with a dead volume C "0 smaller than the dead volume C0 of the figure 2 .

In the continuity of the movement of the crankshaft 38 according to the arrow R with a movement of the crank pin 36 from its 180 ° position to its 0 ° position, the rocker 26 pivots around the pivot 46 under the effect of the link 32 in an anti-lock direction. time by driving, by the rod 20, the piston in a downward movement to its PMB. Once this PMB reached, there remains in the combustion chamber 16 an active volume C "1 which is larger than the volume C1 of the figure 3 .

As a result, the increased cubic capacity (Ca) is larger than the nominal cubic capacity (Cn) because C "1 is larger than C1 and C" 0 is smaller than C0.

The Figures 10 to 12 show another example that the compression ratio of the engine can be modified with, essentially, the same elements as those described in relation to the Figures 1 to 9 .

The figure 10 is an illustration of the engine in a nominal average position with, in solid lines, the piston 14 which is in a median position between its PMH and its PMB and the crankpin 36 of the crankshaft between its 0 ° position and its 180 ° position.

This internal combustion engine comprises at least one cylinder 10, a cylinder head 12 and a piston 14 for delimiting a combustion chamber 16. This piston slides, in a reciprocating rectilinear motion, inside the cylinder between its PMH and its PMB ,

The piston is connected by an articulated piston pin 18 to the connecting rod 20 which is itself connected by an axis 23 to the end 24 of a rocker 126, the other end 28 of which is linked by a hinge pin 30 to the link 32 which is articulated on the crankpin 36 of the crankshaft 38.

The rocker comprises between its two ends a body 140 provided with a bearing 60 receiving a pivot 46 ZZ axis. Advantageously, this pivot is movable in translation in a vertical movement, referring to the figure 10 , relative to a fixed part 50 of the engine but stationary relative to the body 140 of the rocker. This pivot thus makes it possible to define two lever arms of fixed dimensions which may be identical or different, a lever arm 126a between the end 24 of the rocker and the axis of the pivot and a second lever arm 126b between the other end. 28 of the rocker and this same pivot axis,

This pivot is advantageously placed on a sole 48 sliding on the fixed part of the motor 50, as the housing block. As already mentioned in relation to the Figures 1 to 9 , the vertical linear displacement of the pivot and rocker assembly can be provided by any 52V control means known to those skilled in the art, such as a vertical cylinder 54V whose 56V cylinder rod is connected to the rocker. The pivot housed in the bearing 60 of the body 140 allows the rotation of the rocker around the pivot 46 without this pivot being able to move in translation in the body 140.

Of course, a provision similar to that of the preceding figures may be provided with a bearing 60 in the form of vertical light and a pivot placed in this slot and fixedly connected to a fixed part of the motor. In this configuration, only the tipper is subjected to 52V control means to ensure its vertical linear displacement.

In the nominal compression ratio (Tn) configuration as illustrated in FIG. figure 10 the axis ZZ of the pivot 46 is located at a distance H from a fixed point of the engine which, for example, is considered in the plane P passing through the cylinder head gasket between the top of the cylinder and the cylinder head.

Thus, the piston delimits a dead volume T0 in the combustion chamber 16 when this piston is at its TDC, as indicated by the dashed lines of FIG. figure 10 , and an active volume T1 when the same piston is at its PMB (indicated by the double dashes of the figure 10 ). The nominal compression ratio (Tn) is therefore equal to T1 / T0.

When it is planned to increase the compression ratio of the engine, as shown in figure 11 , the rocker, and therefore the pivot 46 associated with the sole 48, are moved by the rod 56V of the cylinder 54V upwards of this figure. By this translational movement, the rocker 126 pivots around the axis 30 of its end 28 in a clockwise direction by driving the piston 14 upwardly. As a result, the height H 'between the fixed point P and the axis ZZ of the pivot 46 is smaller than the height H defined above. Thus, when the pin 36 reaches the 180 ° position starting from the middle position of the figure 11 , the piston 14 delimits at its TDC (broken lines of the figure 11 ) a dead volume T'0 of the combustion chamber 16 which is smaller than the volume T0 of the figure 10 . As the crankpin rotates further to the 0 ° position, the piston ends at the PMB (double dash figure 11 ) under the action of pivoting of the rocker in a counterclockwise direction around the pivot 46 with a volume T'1 smaller than the volume T1 but with a volume swept by the piston (T'1-T'0) which is substantially identical to that of the figure 10 . Consequently, the compression ratio (T'1 / T'0) of the engine of the figure 11 is more important than that of the figure 10 .

Conversely, if you want to reduce the compression ratio of the motor, you just need to get to the configuration of the figure 12 on which the rocker 126, the pivot 46 and its sole 48 are moved in translation by the rod 56V of the cylinder 54V downwardly of this figure by causing a tilting about the axis 30 of the rocker 126 in a counterclockwise direction and that a downward movement of the piston 14. The height H "between the fixed point P and the pivot 46 is accordingly greater than the height H of the nominal compression ratio of the figure 10 . In the 180 ° position of the pin 36, the piston 14 at the TDC defines (broken lines of the figure 12 ) a dead volume T "0 of the combustion chamber which is larger than the volume T0 of the figure 10 . In the situation of the piston at the PMB (double dashes of the figure 12 ) with a crank position at 0 °, this piston defines in the combustion chamber 16 a volume T "1 larger than the volume T1 but with a volume swept by the piston (T" 1-T "0) which is substantially identical to that of the figure 10 . As a result, the compression ratio (T "1 / T" 0) of the engine of the figure 12 is weaker than that of the figure 10 .

We now refer to Figures 13 to 15 which illustrate a combination of the possibility of engine displacement variation Figures 1 to 9 and compression ratio of Figures 10 to 12 while keeping almost all the elements of these types of variation.

In the example shown in figure 13 , the engine includes the same elements as those of Figures 1 to 9 with at least one cylinder 10, a yoke 12, a piston 14 for delimiting a combustion chamber 16 and sliding, in a reciprocating rectilinear motion, inside the cylinder between its PMH and its PMB, a connecting rod 20 connected by a axis 23 at the end 24 of a rocker 26 whose other end 28 is connected to one end of a rod 32 whose other end 34 is articulated on the crankpin 36 of a crankshaft 38.

As previously described in relation to Figures 1 to 9 , the rocker comprises between its two ends a body 40 provided with a longitudinal slot 44 inside which is housed a pivot 46 of axis ZZ mounted on a sole 48 sliding on a fixed part 50 of the engine. Advantageously, locking means 58 between the pivot 46 and the light 44 are provided to immobilize in translation this pivot in the light.

The rocker 26 is, in the case of Figures 13 to 15 , controlled in translation displacement in two substantially orthogonal directions, a first substantially horizontal direction and a second substantially vertical direction by considering these figures.

These linear movements are provided by any control means known to those skilled in the art. By way of nonlimiting example, these means comprise two cylinders with a horizontal cylinder with its jack rod 56, as previously described in relation to the Figures 1 to 9 , for horizontal movement and a vertical cylinder with its 56V rod for vertical movement, as shown in Figures 10 to 13 .

1. I - Taux de compression nominale et cylindrée nominale ;
2. II - Augmentation du taux de compression seul ;
3. III - Diminution du taux de compression seul ;
4. IV - Diminution de la cylindrée seule ;
5. V - Augmentation de la cylindrée seule ;
6. VI - Augmentation du taux de compression et augmentation de la cylindrée ;
7. VII - Diminution du taux de compression et augmentation de la cylindrée ;
8. VIII - Diminution de taux de compression et diminution de la cylindrée ou
9. IX - Augmentation de taux de compression et diminution de la cylindrée.

Thanks to this, it is possible to realize the following different configurations of variation of compression ratio and / or displacement as referenced on the Figures 13 to 15 :

1. I - Nominal compression ratio and nominal displacement;
2. II - Increase of the compression ratio alone;
3. III - Decrease of the compression ratio alone;
4. IV - Decrease of the cubic capacity alone;
5. V - Increase of the cubic capacity alone;
6. VI - Increase of the compression ratio and increase of the cubic capacity;
7. VII - Decrease of the compression ratio and increase of the cubic capacity;
8. VIII - Decrease in compression ratio and decrease in displacement or
9. IX - Increase in compression ratio and decrease in displacement.

So in the nominal configuration I ( figure 13 ), the engine has a nominal compression ratio (Tn) which corresponds to that of the figure 10 with a height H with respect to a fixed point P of the engine and a nominal displacement (Cn) similar to that illustrated in FIG. figure 1 with a lever arm 26a of the length of the rocker L1 and another lever arm 26b of length L2.

In configuration II ( figure 14 ) corresponding to an increase in compression ratio, the pivot 46 is blocked or remains blocked by the means 58 in the light 44 in a central position corresponding to that of the figure 1 . The actuator rod 56V is actuated in the retracted position so as to move the rocker as well as the pivot and its sole relative to the fixed part 50 in a vertical upward movement movement. This action makes it possible to pivot the rocker 26 around its end 28 in a clockwise direction thus bringing the piston 14 of the yoke 12 and decreasing the height of the axis ZZ of the pivot 46 relative to the fixed point P in a height H '. In this configuration, the rocker follows the operation described in connection with the figure 11 obtaining a decrease in the compression ratio of the engine.

From this configuration II, it is possible either to obtain in addition an increase in the displacement with a position of the pivot 46 according to the configuration VI or a reduction of this displacement by placing the pivot in the configuration IX, as illustrated in FIG. figure 15 .

To arrive at this configuration IX, the locking means 58 are actuated to unlock the pivot 46 of the light 44. The rod 56 of the cylinder is actuated to act on the rocker 26 so as to translate it in a horizontal movement to the right of the figure 15 away from the cylinder 10 until the pivot comes into abutment on the end of the light closest to the cylinder. Once this position is reached, the pivot 46 is immobilized in translation in the aperture 44 by the locking means 58 thus generating a lever arm 26'a of length L'1 and a lever arm 26'b of length L ' 2.

In this configuration, the operation of the motor is identical to that described in relation to the Figures 4 to 6 by providing a decrease in displacement in addition to the increase in the compression ratio.

Thus, it is possible not only to vary either the compression ratio or the displacement, but also to associate a variation of compression ratio with a displacement variation.

We are now talking about Figures 16 to 19 which illustrate an exemplary embodiment of the rocker 26 and the pivot as well as control means in displacement of the rocker.

On the Figures 16 and 17 , the rocker 26 comprises an elongate body 40 of axis YY with a first end 24 and a second end 28. An elongated slot 44 of substantially rectangular section of extent D and height E is formed in the median region of the body 40. traversing this body and having both vertical open faces 62 and 64 at a distance N in the front and rear part of this rocker, as shown in FIG. figure 16 . This light comprises two lateral faces 66 and 68 at a distance D from one another and perpendicular to the axis YY and two horizontal faces 70 and 72 at a distance E from each other and substantially perpendicular to the lateral faces. 66 and 68. Oblong grooves 74 and 76 of general axis inclined at an angle α with respect to the axis YY are provided facing each other on the upper and lower parts of the body 40 while passing through the horizontal faces 70 and 72. The extent of each groove is provided in such a way that it is contained in each horizontal face of the light.

This light is intended to house a slide 78 of rectangular parallelepipedal shape of height E 'substantially equal to the height E of this light 44, of longitudinal extent D smaller than the extent D of the light and of depth N' substantially equal to the distance N between the two open faces 62 and 64 of the light. This slider thus comprises two lateral faces 80, 82 at a distance D ', two horizontal faces 84, 86 at height E' and two end faces 88, 90 at a distance N 'from one another. Advantageously, this slide is made of a material allowing it to slide in the light 44.

The slider has a bore 92 traversing from one side to the slider and whose axis Z'Z 'is substantially orthogonal to the end faces 88, 90 being equidistant from the vertical lateral faces 80, 82 and horizontal 84, 86. This slider also bears on the upper and lower horizontal portions two slits 98, 100 of shorter length than the depth of the slider. These slots are facing each other and cross the horizontal portions to open into the bore 92. As visible on the figure 16 , the slots 98 and 100 are of substantially identical direction to the axis Z'Z 'being placed equidistantly between the side faces 80 and 82.

A cylindrical pivot 46 of circular section substantially identical to the bore 92 is provided to be slidably housed in this bore. This pivot comprises a length V between its two end faces 102, 104 which is greater than the depth of the slide 78. This pivot also carries a bore 105 of axis X'X 'substantially perpendicular to the longitudinal axis ZZ of this pivot. This drilling is designed to receive a cylindrical peg 106 passing therethrough forming two projections 108 and 110. Advantageously, this peg has a diameter which is slightly smaller than the width of the slits 98, 100 of the slider so as to allow the sliding sliding of protrusions in these slots. These projections are provided to receive two sliding pads 112, 114 as will be explained in the following description. These pads are advantageously square parallelepiped shaped with two horizontal flat faces 116, 118, two lateral faces 120, 122 of distance substantially equal to the width of the grooves 74, 76, and two end faces 128, 130. Each pad carries a vertical bore 132, 134 opening on both horizontal faces 116 and 118 and slightly smaller in diameter than that of the projections so as to be rotatable around these projections.

The assembly of all these elements is carried out so as to obtain an assembly as illustrated in FIG. figure 17 . To do this, the slider 78 is placed in the light 44 of the rocker 26 so that the slits 98, 100 are opposite the grooves 74, 76 with the axis Z'Z 'of the bore 92 perpendicular to the YY axis of the rocker. The pivot 46 is then introduced coaxially inside the bore 92 with a provision that the hole 105 is opposite the grooves and slots. The pin 106 is inserted through the grooves, slots and the bore so that the projections 108, 110 are placed in the grooves 74, 76 and that the pin is immobilized in the pivot 46, by mounting by especially tightening. Finally the pads 112, 114 are mounted on the projections so that the lateral faces of these pads can slide in the grooves and the lower horizontal faces bear on the slide 78. Of course, these pads are immobilized axially on the projections while being able to rotate circumferentially thereon by any means known to those skilled in the art, such as circlips arranged at the ends of projections.

The set illustrated on the figure 17 is in a nominal position, which corresponds to that of figures 1 or 13 , where the pivot is located in the middle position (D / 2) in the slot 44 leaving a free space I1 and I2 between the side faces 66, 80 and 68, 82 of the slider and the light. In this position, the projections 108 and 110 are located in the middle of the length S of the grooves 74, 76 as well as in the middle of the length of the slots 98, 100. In this position the rocker has a lever arm 26a of length L1 between the axis ZZ of the pivot 46 and the axis of articulation of the end and another lever arm 26b of length L2 between this pivot axis and the axis of articulation of the end 28.

In operation and reporting for better understanding in addition to the figure 18 , it is expected, to reduce the engine displacement as shown schematically on the figure 4 , decreasing the lever arm 26a to a length 1 and increasing the lever arm 26b to a length L'2. To achieve this, a force, such as the action of a cylinder rod, is exerted on one of the end faces 102, 104 of the pivot 46 and in its axial direction (arrows F or F 'of the figure 18 ).

Thus, a pushing action on the rear face 104 of the pivot 46 along the arrow F causes the axial displacement thereof in the slide 78 in a forward movement of the figure 17 . Under the effect of the cooperation of the pads 112, 114 in the inclined grooves 74, 76, the rocker moves on the slide housed in the light 44 to the right (considering the figure 17 ) in a horizontal translational movement until the side face 66 of the light and the side face 80 of the slider are in contact by removing the free space I1. During this movement and given the presence of the slots 98, 100, in which the projections 108, 110 slide, this slide undergoes no forward movement. At the end of this movement horizontal translation, the axis ZZ of the pivot 46 is at a distance 1 of the end 24 of the rocker smaller than the nominal distance L1 and at a distance L'2 of the other end 28 greater than the distance nominal L2. This allows, as described above in relation to the Figures 4 to 6 , reduce the engine displacement.

If it is desired to increase the displacement of this engine either from the nominal position of the assembly or from the displacement reduction position described above, it suffices to exert an action of the opposite direction on the pivot 46. For this, a thrust action on the front face 102 of the pivot 46 along the arrow F '(or a traction action on the rear face 104) causes its axial displacement along the axis ZZ in a movement towards the backwards by considering the figure 17 . During this movement, the cooperation of the pads 112, 114 in the inclined grooves 74, 76 causes a displacement of the rocker and pivot to the left of the figure 17 until the empty space 12 disappears by contact of the side face 68 of the light with the side face 82 of the slider. In this position, the axis of the pivot is at a distance L "1 from its end 24 which is greater than the length L1 and at a distance L" 2 from its end 28 which is smaller than the length L2. Thus, it is allowed to increase the cubic capacity as it is explained in relation to the Figures 7 to 9 .

Of course, those skilled in the art will make all the arrangements to calculate the length S of the grooves and their inclinations α to delimit the extents of the spaces I1 and I2 necessary for the desired variations in displacement.

The Figures 18 and 19 illustrate an embodiment of variation of compression ratio that can be combined with that of the displacement of the engine, as already shown schematically in FIG. Figures 13 to 15 .

This variation in rate is achieved by an eccentric disk 136 adapted to pivot about its axis Z "Z" which has a direction identical to that of the axis Z'Z 'of the pivot 46. This eccentric is placed in a circular housing 138 carried by a fixed part 144 of the engine, as a tab from the engine block. This eccentric door, spaced from the axis Z "Z", a through bore 146 of axis substantially parallel to the axis Z "Z" and of diameter substantially equal to the diameter of the pivot 46 so as to allow rotation and sliding of the pivot in this bore. Advantageously and as shown on the Figures 18 and 19 , there is provided a second eccentric 136 and its support 144 identical and arranged parallel to the first leaving sufficient space and necessary to accommodate the rocker 26. These two eccentric are connected to each other at a point on their peripheral surface 148 by an axial bar 150 so as to simultaneously drive the two eccentrics 136 around the Z axis "Z".

After placing the eccentrics in the housings with a coax of the two bores 146, the rocker 26 with its slider housed in the slot 44 is placed in the space between the two eccentrics so that its axis YY is substantially orthogonal to the axis Z "Z" and that the axis Z'Z 'of the slider is coaxial with that of the bores 146. The pivot 46 which has a length V greater than the spacing between the internal faces of the eccentrics, is then introduced into the bore 146 of one of the eccentrics, the bore 92 of the slider and the bore 146 of the other eccentric 136 to arrive at the position of the figure 18 . The rod 106 and the pads 112 and 114 are then put in place as previously mentioned.

In the nominal position ( figure 19 ) which corresponds to that schematically figures 10 and 13 the axis ZZ of the pivot 46, which coincides with that of the bores 146, is at a height H of a fixed point of the engine.

To increase the compression ratio, an action is exerted on the bar according to the arrow F1 by causing a partial rotation of the eccentrics 136 around the Z axis "Z" and a displacement of the bores 146 and the pivot 46 around this axis in a counterclockwise direction. This allows movement of the entire rocker to the fixed point of the engine. At the end of this rotation, the axis ZZ of the pivot 46 is at a height H 'of the fixed point which is smaller than the height H and which corresponds to the operation schematized on the figure 11 .

Conversely, if it is desired to reduce the compression ratio either from the position obtained above or from the nominal position, an action according to the arrow F'1 is exerted on the bar 150. This action has the effect of rotating the eccentrics around the Z "Z" axis in a clockwise direction by moving the bores 146 in the same direction and moving the rocker assembly away from the fixed point. As a result, the height H "of the axis ZZ of the pivot 46 is at a distance H" greater than the height H or the height H '. This position corresponds to the schemas of the figure 12 for which the operation applies.

The present invention is not limited to the example described above in which, for both the displacement variation and the variation of the compression ratio, the pivot is in each case in extreme positions, such as abutting on the ends of the light 44.

It may be envisaged that this pivot can occupy all positions between its nominal position and the extreme positions so as to achieve a multiplicity of displacement and / or compression rate variations.

Claims (4)

1. An internal combustion engine including at least one cylinder (10) in which a piston (14) slides between a top dead centre (TDC) and a bottom dead centre (BDC) under the action of a connecting rod (20) having an axis XX and a crankshaft (38) which causes said piston to be displaced under the effect of a hinged link system (26) which makes it possible to vary the swept volume and/or the compression ratio of the motor, said hinged link system including a rocker (26) pivotably mounted around a hinge pin (46) and displaceable in translation along at least one direction by displacement control means (52, 52V), said rocker including an opening (44) inside which said axle is accommodated and being linked by one (24) of its ends to said connecting rod and by the other (28) of its ends to a connecting link (32) linked to said crankshaft, and a slide (78) which bears the hinge pin (46) and cooperates with the opening (44) of said rocker, characterised in that the rocker (26) bears sloping grooves (74, 76) which cooperate with the projections (108,110) borne by the hinge pin and passing through the slide through slots (98, 100) and In that the hinge pin (46) bears end faces (102, 104) on which there is applied a force (F, F') In order to bring about the displacement of said axle.
2. The Internal combustion engine according to Claim 1, characterised in that the displacement control means Include an eccentric member (136) bearing a receiving bore (146) for the hinge pin (46).
3. The internal combustion engine according to Claim 2, characterised in that the displacement control means include two eccentric members (136) arranged parallel to each other and between which there is placed the rocker with its hinge pin.
4. The internal combustion engine according to Claim 2 or 3, characterised In that the eccentric member bears a control means (150) for rotation around Its axis.

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