EP1018597B1 - Charged two or four stroke internal-combustion engine - Google Patents

Description

The present invention relates to a compressed engine with two or four-stroke internal combustion with one or several cylinders, and operating by admission of fuel mixture or by admission of fresh air with direct or indirect injection of fuel. The invention applies equally well to the gasoline engine equipped spark plugs, to the diesel engine whose ignition is obtained by compression.

Although the invention is described in the following more particularly with reference to a single-cylinder engine for the engine two-stroke, which is well suited for all small applications industrial engines intended for the motoculture, garden tools, lawn mowers, chainsaws, brush cutters or the invention is in no way limited and applies also to multi-cylinder engines with two or four strokes, online or in V.

We already know a two-stroke single-cylinder engine that works by natural aspiration in the cylinder of a mixture carburetor that passes through the cylinder housing. This engine has a intake pipe of the air / fuel mixture and a pipe exhaust gases, both of which emerge through lights in the lower part of the cylinder, in the vicinity of the Low Dead Point (PMB). The carbureted mixture from the carburetor is sucked into the casing through a valve, during the ascending phase of the piston which causes a depression in the crankcase, then is pushed back towards the cylinder, during the downward phase of the piston generating a overpressure in the crankcase. During the downward phase of the piston, the mixing inlet lights open substantially at the same time as the exhaust lights, so that about 20% of the mixture is directly discharged to the exhaust, causing high fuel consumption and pollution atmospheric. The main advantage of this engine is its low cost, but the new anti-pollution standards condemn, ultimately, this type engine.

Another known engine is the loop-scan type, which works with a volumetric compressor, for example of the type Roots, to facilitate the introduction of the fuel mixture into the cylinder and generate supercharging at low pressure. This engine features also a pipe of admission of the mixture and a pipe exhaust pipes, both of which open lights in the lower part of the cylinder. In this engine, the mixture fuel is admitted into the cylinder from the compressor, with a orientation such that the mixture undergoes rotational movement looping ascending, like a looping, in the cylinder, while the burned gases from the previous cycle are removed by the exhaust lights. The particular arrangement of the lights intake and exhaust makes it possible not to send directly to the exhaust part of the admitted mixture, which reduces at a time consumption and pollution of the environment.

Yet another known engine is of the "uniflow" type which also works with a volumetric compressor. This engine has an intake pipe connected upstream to the compressor and downstream to an intake crown that leads through a plurality lights in the lower part of the cylinder, with an orientation such that the mixture is introduced with a large rotational movement. The burnt gases are evacuated at the top of the cylinder through one or several exhaust valves. This type of engine allows check the filling of the cylinder and the possible recycling of the gases burned to achieve cleaner combustion. Otherwise, when this type of engine runs on diesel, the introduction of air in the lower part of the cylinder makes it possible to obtain a very strong movement of rotation of the air, which is necessary to obtain a good performance. This engine makes it possible to consume even less fuel than the loop scanning motor and also reduces polluting emissions to the outside.

However, these last two types of motor have a cost superior to the crankcase transfer motor because they have more of organs, in particular the compressor, and in addition, for the engine uniflow, a valve control. In addition, the compressors Roots type have low efficiency, for example an engine two-stroke single cylinder having a displacement of one liter and one power of 55kW, consume 17kW to drive the compressor. In addition, a Roots compressor does not operate beyond a pressure above 1.2 bar.

Finally, we know the engine with exhaust valves and of admission, which makes it possible to obtain the lowest consumption and pollutant emissions, but this engine is also the more expensive because it requires to control both the valves exhaust and intake. The efficiency of this engine is better because the control of the opening and closing of the valves by external parts to the cylinder, allows to use the whole race of the piston, whereas with the previous engines where the admission takes place by lights, a part of the compression stroke and the race relaxing is lost.

WO-A-9 318 287 discloses an engine according to the preamble of claim 1.

The object of the invention is to propose a compressed engine to internal combustion with two or four strokes, for example Loop sweep, uniflow or valve, or four-stroke to which improves performance and reduces polluting emissions.

For this purpose, the subject of the invention is a combustion engine internal device according to claim 1.

According to the invention, the angle of the dihedron, whose edge is formed by the axis of the crankshaft and whose two half-planes extend respectively to the eccentric and the crankpin, is of the order of 90 ° to obtain a phase shift between the top dead centers (TDC) of the engine piston and compressor piston associated with the same cylinder, phase shift which ensures maximum pressure in the chamber compression prior to admitting the fuel mixture or fresh air in the combustion chamber.

In this case, when the stage of the compression chamber, which communicates directly with the cylinder, is located between the piston of compressor and the crankshaft, the crankpin is out of phase in advance by relative to the eccentric in the direction of rotation of the crankshaft, and conversely, when the aforementioned stage is located on the piston side of compressor opposite the crankshaft, the eccentric is out of phase in advance with respect to the crankpin in the direction of rotation of the crankshaft.

Advantageously, the displacement of the compressor is of the order of the size of the cylinder, but with a compressor piston having a diameter significantly greater than the diameter of the engine piston, to obtain a low compression stroke of the piston of compressor in the compression chamber.

In a particular embodiment, the chamber of compression is two stages located on either side of the piston of compressor, a first stage being supplied with a fuel mixture or fresh air through a first non-return valve or valve, and connected by a discharge pipe provided with a second non-return valve or a valve, on the second floor which communicates with the cylinder by an intake manifold possibly equipped with a third valve anti-return or a valve. The use of a compressor with two stages allows to obtain a higher boost pressure in the cylinder. However, in this case, the volumetric ratio of the cylinder may be reduced so as not to reach maximum pressure of combustion which is incompatible with the mechanical strength of the cylinder. The engine equipped with this two-stage compressor will work similarly to the known supercharging system of type hyperbar.

The two-stroke engine of the invention can also be equipped with a device for recovering energy from puffs Exhaust and partial recirculation of exhaust gas providing an additional volume communicating with the cylinder to through means of closing and opening, whose movements are controlled synchronously or out of phase with those of the piston in the cylinder, so that during the relaxation phase, the flue gases compress the air in the additional volume penetrating at least partially, that this mixture air and gas burned be trapped under pressure, then that mixture is admitted into the cylinder during the compression phase.

Advantageously, after the mixture of air and gas burned previously trapped in the additional volume, was admitted into the cylinder, said additional volume is again filled with fresh air in from the compressor.

According to another characteristic, the sealing means and mentioned above comprise two rotary shutters, for example rotary bushels with several lanes, interconnected by the additional volume, one of the shutters being associated with the compressor and the other shutter at the exhaust of the cylinder.

Preferably, the two rotary shutters are arranged way that the following operations occur: in a first time, when the engine piston is in the vicinity of its TDC, a airflow from the compressor passes through the lower shutter associated with the compressor, sweeps the additional volume, crosses the upper shutter associated with the exhaust and escapes to the outside by an exhaust manifold; in a second time, from about half of the expansion stroke of the engine piston, on the one hand, the upper shutter communicates the cylinder with the additional volume to fill it with an air and gas mixture burned under pressure, and secondly, the cylinder communicates with the exhaust; in a third time, the upper shutter trap the mixture of air and gas burned in the additional volume; in one fourth time, the air coming from the compressor is admitted into the cylinder, and in a fifth time, at the beginning of the race of compression of the engine piston, the mixture entrapped and under pressure is admitted into the cylinder.

In a first variant, the upper shutter is associated with at least one exhaust valve located at the top of the cylinder and the lower shutter is connected to the cylinder by a pipe arranged in the lower part of the cylinder, so that the additional volume is set under pressure by its upper end by means of flue gases from the exhaust valve through the shutter higher, and is emptied into the cylinder by its lower end to through the lower shutter.

In a second variant, the upper shutter is connected to the cylinder by a pipe arranged at the bottom of the cylinder and the lower shutter is interposed on the discharge pipe between the two stages of the compressor, so that the volume additional amount is pressurized using the flue gases from of the cylinder through the upper obturator and be emptied into the cylinder by the pipe connected to the upper shutter.

Advantageously, for two or four stroke engines, the intake pipe towards the cylinder and / or the pipe of discharge of the two-stage compressor is cooled by all means appropriate.

The two-stroke engine may be of the loop scan type, in which the fuel mixture or the fresh air is admitted from the compressor through an intake manifold opening through lights at the bottom of the cylinder with an orientation such that the mixture or the air is introduced with an upward rotating movement in a loop, while the flue gases of the previous cycle are discharged by exhaust lights also arranged in the lower part of the cylinder.

The two-stroke engine can still be of the uniflow type, in which the fuel mixture or the air is admitted in the lower part of the cylinder through intake lights distributed at the base of the cylinder and fed by a ring itself connected to the compressor, then that the burned gases from the previous cycle are discharged through one or several exhaust valves provided at the top of the cylinder.

Finally, the two or four stroke engine can be of the type to exhaust and intake valves, in which the valves are at the top of the cylinder and the intake valve (s) are powered by the compressor.

The invention also applies to a multi-type motor cylinders, in which the compressors associated with each cylinder are alternately arranged on each face of the housing cylinder.

To better understand the object of the invention, we will describe now, as purely illustrative and non-illustrative examples restrictive, several embodiments shown in the drawing Annex.

• la figure 1 est une vue schématique en coupe verticale d'un premier mode de réalisation utile à la compréhension du moteur de l'invention, du type à deux temps à balayage en boucle, à compresseur mono-étage et à piston de compresseur basculant avec un agrandissement partiel de ce dernier ;
• les figures 2A à 2D sont des vues partielles analogues à la figure 1 et en coupe verticale suivant la ligne II sur la figure 3, représentant respectivement le piston de moteur à son PMH, en cours de détente, à son PMB et en cours de compression, pour un moteur à deux temps ;
• la figure 3 est une vue en coupe suivant la ligne III de la figure 2A ;
• la figure 4 est une vue analogue à la figure 1, mais suivant une variante dans laquelle le piston de compresseur est à déplacement linéaire, avec un agrandissement partiel de ce dernier ;
• les figures 5A à 5D sont des vues analogues aux figures 2A à 2D et en coupe verticale suivant la ligne V sur la figure 6A, mais représentant une autre variante selon l'invention, dans laquelle le piston de compresseur est une membrane déformable et le cylindre est équipé d'une bougie d'allumage ;
• les figures 6A à 6D sont des vues en coupe suivant la ligne VI des figures 5A à 5D respectivement, avec un agrandissement partiel de ladite membrane sur la figure 6A ;
• la figure 7 est une vue en coupe suivant la ligne VII de la figure 5A ;
• la figure 8 est une vue analogue à la figure 4, mais représentant un moteur à deux temps à compresseur bi-étages ;
• la figure 9 est une vue analogue à la figure 8, mais représentant le moteur à deux temps équipé, en outre, d'un système de recirculation partielle des gaz d'échappement ;
• les figures 10 et 11 sont des vues analogues respectivement aux figures 1 et 4, mais représentent un deuxième mode de réalisation du moteur à deux temps utile à la compréhension de l'invention du type uniflow ;
• la figure 12 est une vue analogue à la figure 11, mais représentant le moteur à deux temps équipé d'un compresseur bi-étages ;
• la figure 13 est une vue analogue à la figure 12, mais représentant le moteur à deux temps équipé, en outre, d'un système de récupération de l'énergie des bouffées d'échappement :
• les figures 14 et 15 sont des vues analogues aux figures 1 et 4 respectivement, mais représentent un troisième mode de réalisation du moteur à deux temps utile à la compréhension de l'invention, du type à soupapes d'échappement et d'admission ;
• la figure 16 est une vue schématique de dessus d'un moteur à quatre cylindres en ligne utile à la compréhension de l'invention ;
• la figure 17 est une vue analogue à la figure 15, mais représentant un moteur à quatre temps équipé d'un compresseur bi-étages ;
• les figures 18 à 25 sont des vues partielles et en coupe, analogues à la figure 14, représentant un moteur à quatre temps au cours des différentes phases successives de son cycle.

On this drawing :

• FIG. 1 is a diagrammatic view in vertical section of a first embodiment useful for understanding the motor of the invention, of the two-stroke type with loop scanning, single-stage compressor and tilting compressor piston with a partial enlargement of the latter;
• FIGS. 2A to 2D are partial views analogous to FIG. 1 and in vertical section along the line II in FIG. 3, respectively representing the engine piston at its TDC, being released, at its PMB and being compressed , for a two-stroke engine;
• Figure 3 is a sectional view along the line III of Figure 2A;
• Figure 4 is a view similar to Figure 1, but in a variant in which the compressor piston is linear displacement, with a partial enlargement of the latter;
• FIGS. 5A to 5D are views similar to FIGS. 2A to 2D and in vertical section along the line V in FIG. 6A, but representing another variant according to the invention, in which the compressor piston is a deformable membrane and the cylinder is equipped with a spark plug;
• Figs. 6A to 6D are sectional views taken along the line VI of Figs. 5A to 5D respectively, with partial enlargement of said membrane in Fig. 6A;
• Figure 7 is a sectional view along the line VII of Figure 5A;
• Figure 8 is a view similar to Figure 4, but showing a two-stage compressor two-stage compressor;
• Figure 9 is a view similar to Figure 8, but showing the two-stroke engine further equipped with a partial recirculation system of the exhaust gas;
• Figures 10 and 11 are views similar respectively to Figures 1 and 4, but show a second embodiment of the two-stroke engine useful for understanding the invention of the uniflow type;
• Figure 12 is a view similar to Figure 11, but showing the two-stroke engine equipped with a two-stage compressor;
• FIG. 13 is a view similar to FIG. 12, but showing the two-stroke engine further equipped with an energy recovery system for the exhaust puffs:
• Figures 14 and 15 are views similar to Figures 1 and 4 respectively, but show a third embodiment of the two-stroke engine useful for understanding the invention, the type of exhaust valves and intake;
• Figure 16 is a schematic top view of a four-cylinder in-line engine useful for understanding the invention;
• Figure 17 is a view similar to Figure 15, but showing a four-stroke engine equipped with a two-stage compressor;
• Figures 18 to 25 are partial views in section, similar to Figure 14, showing a four-stroke engine during the various successive phases of its cycle.

For the sake of clarity, in all the figures, the elements identical or similar will bear the same reference numbers.

Figures 1 to 9 show various variants useful for understanding the invention applied to an internal combustion engine 1 single cylinder to two time and loop scan.

In the first variant shown in FIGS. 1 to 3, the 1 comprises a cylinder 1 defined between the cylinder block 2 and the cylinder head 3 of the engine. The breech 3 has a recess 3a in upper part of cylinder 1 to define a combustion chamber because the proposed representation is that of a gasoline engine. The invention can be applied equally well to a diesel engine with direct injection or indirect.

In the cylinder 1, a piston of engine 4 which defines a combustion chamber 5 inside the cylinder 1 between the cylinder head 3 and the piston 4. The engine piston 4 is provided at its periphery with sealing segments 6 shown on the Figure 1. A rod 7 is articulated by its small end 7a to the piston 4 and by its connecting rod head 7b at the crankpin 8 of a crankshaft 9.

An eccentric 10 is mounted on the crankshaft 9 and articulated on a rod 11 which is rigidly fixed in the center of a compressor piston 12 in the form of a disc. The piston of compressor 12 has at its periphery a spherical border 12a provided with a sealing segment 13 also with a spherical edge, which is immobilized in rotation with respect to the compressor piston, in a position such that the slot of the segment 13 is not placed in lower part of the housing 2. The compressor piston 12 moves alternatively by tilting inside the chamber of compression 14a of a single-stage compressor 14 attached to the housing 2. The compression chamber 14a of the compressor 14 is supplied with fuel mixture or fresh air through a suction pipe 15 equipped with a non-return suction valve 15a. The fuel mixture or the pressurized fresh air is discharged from the compressor 14 to a intake pipe 16 provided with a non-return check valve 16a. The intake pipe 16 opens at the bottom of the cylinder 1 by a plurality of lights 17 which have an orientation such that that the mixture or air under pressure is introduced with a movement of ascending rotation in a loop in the cylinder in the manner of a looping. The cylinder 1 is further provided with one or more pipes exhaust 18 which open at the bottom of the cylinder, substantially at the same level as the intake ports 17.

As can be seen in FIG. 1, the eccentric 10 is shifted by one angle  of the order of 90 ° with respect to the crankpin 8, in the direction of rotation of the crankshaft, as indicated by the arrow F, so that the TDC of the engine piston 4 is 180 ° out of phase with the TDC of the compressor piston 12. Referring to FIG. the axis of the rod 11 of the compressor 14 is shifted by a distance d relative to the axis of the connecting rod 7 of the engine piston 4.

The cylinder capacity of the cylinder 1 is substantially of the same order of magnitude than the compressor's capacity 14, but the piston of compressor 12 has a diameter much greater than that of the engine piston 4, so that the compression stroke c of the piston compressor 12 is relatively low.

Finally, the intake pipe 16 may be provided with a heat exchanger 19, conveying a refrigerant, for example water, or fresh air can be blown for a motor to air cooling, for cooling the air leaving the compressor 14, which makes it possible to increase the air mass admitted into the cylinder 1, especially as the compression of air in the compressor 14 releases a large amount of heat. However, the cooling of the intake pipe 16 is optional.

Referring now to Figures 2 and 3, we see that the crankpin 8 of the crankshaft 9 is provided opposite to the small end 7b a counterweight 20 which serves as a counterweight.

We have indicated by broken lines in FIG. PMH and PMB positions of the engine piston 4.

It is also indicated, in phantom in Figure 1, the path of the eccentric 10 and the path of the crankpin 8.

We will now describe the operation of this engine in reference to Figures 2A to 2D.

In FIG. 2A, the engine piston is at the end of compression, at its PMH, while the compressor piston 12 is at its PMB, that is to say in its rightmost position in Figure 2A. Being relaxation, under the action of the combustion of gases in the chamber of combustion 5, the engine piston descends, as shown in the figure 2B, after a rotation of about 90 ° of the crankshaft 9, which causes simultaneously the tilting of the compressor piston 12 around its upper portion, thus generating a first compression in the compression chamber 14a. At the end of relaxation, the engine piston 4 arrives at his PMB, simultaneously discovering the tubing exhaust 18 and the intake ports 17, after a rotation additional 90 ° of the crankshaft 9. Simultaneously, the piston of 12 compressor rocking around its lower portion to reach its leftmost maximum compression position in the chamber compression 14a, which causes the admission of air or carburetted mixture under pressure in the combustion chamber 5, thus flushing the exhaust gases and filling the cylinder. In FIG. 2D, the engine piston is shown in FIG. of its compression phase, after an additional rotation of 90 ° crankshaft, which closes both the exhaust and the intake and causes the compressor piston 12 to tilt around its upper portion, and thus a first relaxation of the chamber of compression 14a, the fresh air or the fuel mixture being sucked by the suction pipe 15, because of the depression thus generated in room 14a. Finally, when the engine piston 4 arrives at its TDC shown in Figure 2A, after an additional 90 ° rotation of the crankshaft 9, the compressor piston 12 tilts around its lower portion, to bring it back to its rightmost position, fresh air or fuel mixture thus continuing to be sucked into the compression chamber 14a. The cycle of operation that comes to be described is thus repeated successively.

As shown in FIGS. 2A to 2D, the eccentric 10 is formed by a disc mounted eccentrically on the shaft of crankshaft 9.

However, because of the alternative tilting of the piston of compressor 12, there is a risk that the oil contained in the crankcase passes into the compression chamber 14a, causing a oil consumption and pollution of the environment because the oil is thus evacuated to the outside.

This disadvantage is removed in the variant illustrated on the Figures 4 to 7, where the swinging compressor piston 12 is replaced by a compressor piston 112 shown in Figure 4 which moves alternatively in linear translation in the compression chamber 14a.

This compressor piston 112 also has at its periphery a sealing segment and comprises at its center a rod 121 rigidly attached to the compressor piston 112 and articulated to its free end to the rod 11 of connection with the eccentric 10. The rod 121 is guided in translation by a guide sleeve 122 which is connected to the casing 2 by a vertical partition 123. The sleeve 122 can be equipped internally with a sealing ring crossed by the rod 121, or alternatively a sealing bellows S can be connected between the rod 121 and said vertical partition 123, which eliminates any risk of oil passing between the crankcase and the compressor.

In FIGS. 5 to 7, it can be seen that the cylinder 1 as well as the compressor 14 are provided with cooling fins 21.

At the top of the cylinder 1 is arranged a spark plug 22.

The motor M1 is constituted here of a first block which forms the cylinder 1, a second block which forms the casing 2 and a third block that forms the compressor 14. As a result, the compressor piston 112 in the form of rigid disk can be replaced by a membrane deformable 212 whose periphery is fixed between the second and third blocks mentioned above. To facilitate membrane deformation 212, a corrugation 212a may be provided in the vicinity of its periphery, as shown in Figure 6A.

As best seen in FIGS. 6A to 6D, the rod 121 connects the center of the deformable membrane 212 to an articulated cross member 124 whose free ends slide in a groove 125 provided in the casing 2 and are each connected to two arms 111, which extend from on either side of the axis of the compressor 14. The connecting rod the eccentric is thus formed by the whole of the crossbar 124 and two arms 111. The two arms 111 of the link are each mounted on a disk 10 which is respectively mounted eccentrically on the shaft 9 of the crankshaft between the side wall of the housing 2 and an arm of the crank pin 8. Needle roller bearings 22 to 24 are respectively provided at the free ends of the cross member 124, between each link arm 111 and the eccentric disc 10, and at the level of the shaft 9. However, if the rotation is slow enough, these bearings can be replaced by ball bearings or by slip rings.

As can be seen in FIG. 7, in this case, the axis of the piston of compressor is centered on the axis of the engine piston, unlike the variant of the tilting compressor piston of Figures 1 to 3.

The operating cycle of this engine including the piston of compressor is mounted with a tie rod, is substantially the same as that of the tilting piston engine. When rotating the crankshaft 9, the cross member 124 moves in rectilinear translation in the grooves 125, which causes the displacement of the rod 121 which causes a deformation of the membrane 212. In FIG. 5A, the 4 engine piston is at its PMH, and the diaphragm is deformed into bending to the right towards the crankshaft. In Figure 5B, the engine piston is halfway through its relaxation phase, and the membrane 212 is in a substantially flat, vertical position. Sure 5C, the engine piston 4 is at its PMB, and the diaphragm 212 is deformed in flexion to the left, opposite the crankshaft. Finally, in FIG. 5D, the engine piston 4 is halfway in its upward stroke of compression, and membrane 212 is again in a flat position, at rest.

By way of example, the motor shown in FIGS. comprises a cylinder 1 having a diameter of about 42 mm and a useful stroke of 38 mm for the engine piston 4, and a compressor 14 having a diameter of 80 mm, with a useful stroke of about 8.5 mm for the compressor piston 212.

The variant illustrated in Figure 8 differs from the variant represented in FIG. 4, essentially by the fact that compressor 14 has a two-stage compression chamber 14a and 14b. The first stage 14b is formed between the partition 123 and the compressor piston 112, while the second stage 14a is formed on the other side of the compressor piston 112. The first stage 14b comprises in the upper part a suction pipe 115 provided with a check valve 115a. This first stage 14b is crossed by the rod 121 of the compressor piston 112. In the lower part of the first stage 14b, there is provided an intermediate discharge pipe 130 which communicates in the lower part of the second stage 14a of the compressor 14. This intermediate discharge pipe 130 is provided with a check valve 130a and a cooling system 19. The second stage 14a of the compressor 14 communicates in the upper part with the intake manifold 16, similarly to the compressor single stage described in Figures 1 to 7.

The different valves 115a, 130a and 16a of the compressor 14 and the valves 118a and 217 of the motor, can be advantageously replaced by mechanically or electronically controlled valves or hydroelectronics, which can be managed by a calculator digital technology, in order to drive on demand all the motor parameters, to know the compression ratio in the compressor and / or in the engine cylinder, as well as the relaxation rates.

Although Figure 8 shows a compressor piston 112 in hard plane disk shape, it could just as easily be replaced by a deformable membrane similar to that shown on the Figures 5 and 6.

During the compression phase of the engine piston 4, the piston compressor 112 moves to the right, to compress the first stage 14b of the compression chamber, which causes the backflow of air through line 130 to the second floor 14a. During the descending phase of relaxation of the engine piston 4, the compressor piston 112 moves to the left, causing an overcompression of the air contained in the second stage 14a, which can go back through the pipe 130, because of the non-return valve 130a, and thus escapes to the intake pipe 16 to a pressure higher than that which would be obtained with a compressor mono-floor. Simultaneously, a depression is generated in the first stage 14b, which causes the suction of the air from the suction tubing 115.

In FIG. 8, the stroke of the compressor piston 112 has been indicated in c .

In FIG. 9, the motor of FIG. 8 is equipped with a device of energy recovery from exhaust puffs and partial recirculation of the exhaust gas, the principle of which is described in detail in the French patent application No. 98-07835 of 22 June 1998 belonging to the present applicant.

An additional volume 40, which may have any suitable shape, communicates in the lower part with a pipe 41 which leads to a rotary shutter 42, for example, a bushel turning three tracks, which is interposed on the discharge pipe 130 mentioned above, downstream of the valve 130a. Additional volume 40 communicates also, in the upper part, with a pipe 43 which leads to a second upper rotary shutter 44, for example a bushel three-way, the latter communicating, on the one hand, by a duct 45 in the lower part of the cylinder 1, and, on the other hand, by a pipe 46, with an exhaust manifold (not shown) connected to the exhaust pipe 18 above.

We will now describe the operation of the illustrated engine in Figure 9.

When the engine piston 4 arrives near its TDC, in the compression phase, the lower bushel 42 communicates the first stage 14b of the compressor 14 with the line 41, while closing the passage to the second floor 14a, while the bushel upper 44 communicates line 43 with the pipe exhaust 46, while closing the passage to the pipe 45 which opens at the bottom of the cylinder 1. As a result, the air compressed by the compressor piston 112 in the first stage 14b is evacuated to the exhaust, by sweeping the additional volume 40, the the remainder of the mixture of air and flue gases in this volume 40 thus being evacuated to the outside and replaced by fresh air.

Then, at the beginning of the relaxation phase of the engine piston 4, shown in FIG. 9, bushels 42 and 44 close off all communication, the rotation of the bushels being able to be enslaved to the rotation of the crankshaft 9, or controlled by a central unit of electronic management.

When the engine piston 4 arrives substantially at the end of relaxation, the engine piston 4 discovers the opening of the pipe 45 and the combustion gases under pressure in the cylinder 1 then escape through this pipe 45 and pass through the shutter 44 to the additional volume 40, the upper shutter 44 being in a closed position of the exhaust pipe 46. Simultaneously, the shutter 42 closes the passage of the pipe 41, so that the flue gases compress the air that is in the additional volume 40 and enter it partially.

Simultaneously, or shortly after the opening of Line 45, the engine piston 40 also discovers the exhaust manifold 18, to evacuate the rest of the flue gases, which are driven out by the fresh air under pressure introduced by the intake ports 17 and coming from the second stage 14a of the compressor, under the compression action exerted by the compressor piston 112 which moves to the left. When the engine piston 4 reaches its PMB, the upper bushel 44 closes any communication and the lower bushel 42 opens the passage between the first and second stages of the compressor, while now closed the passage to Line 41, so that the mixture under pressure air and flue gas, which was in the volume additional 40 is trapped there. At PMB, the scan of cylinder 1 is ends and the latter begins to fill with fresh air to the high pressure delivered by the compressor 14.

When the compression phase begins in the cylinder, the compressor piston 112 represses the compressed air in the first stage 14b to the second stage 14a, through the lower bushel 42 which keeps open the communication of Line 130, while now closed the passage to Line 41. Simultaneously, the upper bushel 44 opens the passage between the additional volume 40 and the cylinder 1, while keeping the passage towards the exhaust pipe 46, so that the air and gas mixture burned that is trapped in volume 40 can escape through pipes 43 and 45 in the cylinder 1, which achieves both a supercharging in cylinder 1 and a recovery of energy from exhaust puffs.

When the engine piston 4 exceeds approximately halfway its ascending phase, exhaust manifold 18 and line 45 are closed by the engine piston 4 and the bushels 44 and 42 are move progressively towards the position that puts in communication the first stage 14b of the compressor with the exhaust 46.

Note that, in this case, the bi-stage compressor 14 presents less effective than in the case of Figure 8, because part of the compression stroke of the first stage 14b of the compressor 14 is used to scan the additional volume 40.

We will now describe the application of the invention to an engine single-cylinder two-stroke type uniflow M2, with reference to Figures 10 to 13.

The three variants shown respectively in FIGS. 12 correspond to the variants represented in FIGS. 1, 4 and 8 of FIG. looped motor. In these circumstances, the operation of the uniflow M2 motor will be described only once for all of these three variants.

In a uniflow motor, as shown in FIG. intake duct 16 opens on an annular ring 117 surrounding the lower part of the cylinder 1, said ring 117 having a plurality of lights (not shown) that partially open cylinder 1 with an orientation such that air is introduced in the cylinder with a large rotational movement. The exhaust pipe 118 is provided at the top of the cylinder 1 and has at least one valve 118a which is controlled by all adapted way.

When the engine piston 4 is at its TDC, the one or more 118a exhaust valves are closed, as well as the lights which are blocked by the piston body of the engine. end of expansion of the engine piston 4, the exhaust valve or valves 118a open, to evacuate the burnt gases, and the engine piston 4 discovers the lights of the intake crown 117, so that the compressed air coming from the compressor 14 flushes up the gases burned towards the exhaust. The filling of the cylinder 1 in combustion air continues until the beginning of compression of the piston motor 4, as long as the intake lights remain uncovered by the engine piston 4.

In the variant of FIG. 13, the motor M2 is also equipped with a device for recovering energy from puffs exhaust and partial recycling of the exhaust gas. This device comprises an additional volume 140 which is formed by a adapted section pipe communicating at both ends with a rotary shutter 142, 144 which can be constituted by a bushel rotating several ways. The upper bushel 144 communicates, in addition, with the exhaust pipe 118, downstream of the exhaust valve (s) 118a provided at the top of the cylinder 1, and with two other pipes 145 and 146 which end to an exhaust manifold, not shown.

The lower bushel 142 communicates, moreover, with a pipe 141 which opens at the bottom of the cylinder 1, above of the intake ring 117, and with the intake pipe 16.

The rotary movements of the bushels 142, 144 are linked by in all appropriate ways, known to those skilled in the art and therefore not described, to the rotary motion of the crankshaft 9, in ratio 1/1 or different from 1/1, phased or out of phase with the movement of the crankshaft.

In addition, in FIG. 13, the positions of the two stages 14a and 14b of the compressor 14 are reversed relative to the piston of compressor 112. Indeed, the inlet pipe 16 communicates with the stage 14b which is located between the compressor piston 112 and the vertical wall 123, while the first stage 14a located on the side of the compressor piston 112 opposite the crankshaft 9, is supplied with air through the suction line 115. As a result, the operation the compressor 14 is reversed, and the crankpin 8 of the crankshaft must be out of phase with an angle  of approximately 90 ° with respect to the eccentric 10, in the direction of rotation F of the crankshaft 9.

When the engine piston 4 is at its TDC, the valve 118a or the exhaust valves that are eventually provided, are closed as well as bushels 142 and 144.

During the expansion phase of the engine piston 4, the 118a exhaust valves open and top shutter 144 rotates, for example in the same direction as the crankshaft 9, to make communicate the exhaust pipe 118 with the pipe 140 forming the additional volume. The lower bushel 142a also turned the same amount in the same direction but this did not brought no communication of pipelines. It results that a puff of gas burned under pressure is repressed via the exhaust pipe 118 in the pipe 140, which compresses the air in it while introducing a portion of gas burned, corresponding to the angular period of transfer.

When the engine piston 4 reaches an intermediate position between the line 141 and the intake ring 117, the 118a exhaust valves are still open, but the bushel 144 having turned puts into communication the pipes 118 and 145, while closing the passage to the line 140; the bushel lower 142 also turned, but without realizing communication. As a result, the air / gas mixture burned, which was previously introduced under pressure (about 3.5 bar at full load) in Line 140, is trapped there and that the burned gases escape through line 145 to the exhaust manifold.

When the engine piston 4 reaches its PMB, the shutter 144, although having continued to rotate, maintains the communication between the pipes 118 and 145; shutter lower 142 also turned, but without realizing communication; the lights of the intake crown 117 are unmasked. As a result, the air coming from floor 14b of compressor 14 runs a sweep that vents the gases burned through the exhaust valve 118a and the cylinder 1 fills with air at the relatively high pressure of the compressor 14. The mixture Air / flue gas is still trapped under pressure in Line 140.

When the engine piston 4 begins its phase of compression, it closes the lights of the crown of admission 117 and outcropping at Line 141; the shutter 142 having continued to turn, pipes 118 and 145 may still be communicating, but this is ineffective because the valve or valves exhaust 118a are closed; the lower bushel 142 sets communication channel 141 with line 140. In results that the air / gas mixture burned, which was trapped under pressure in this pipe 140, escapes and fills the cylinder 1 under pressure. This achieves both a supercharging of the cylinder and a partial recirculation of flue gases, known as Exhaust Gas Recirculation (EGR), which has the effect of reducing Nitrogen oxide emissions at low speed.

When the engine piston 4 continues its compression, until close the line 141, the exhaust valve 118a remain closed, and the bushels 142, 144 pivot in a position where all communications are prohibited.

When the engine piston 4 arrives substantially at the end of compression, the exhaust valve 118a remains closed, but the upper bushel 144 ports the pipeline 140 with line 146; the lower bushel 142 sets communicating the pipe 140 with the intake pipe 16. As a result, the fresh air from the compressor 14 flows through the pipes 16, 140 and 146 for evacuating the residual air / gas mixture burned in line 140 to the outside.

When the engine piston reaches the TDC, the cycle is ready to restart.

FIGS. 14 and 15 show the application of the invention to an M3 engine of the two-stroke single-cylinder type and to exhaust and intake valves.

Figures 14 and 15 show two variants that correspond to the variants of FIGS. 10 and 11 of the motor M2 of the type uniflow.

The only difference, which is common to both variants, is in that the intake pipe 16 opens at the top of the cylinder 1 where is provided one or more intake valves 217. The operation of this type of engine is similar to the previous ones.

Although both variants of Figures 14 and 15 have a mono-stage compressor, one could also provide a two-stage compressor (see engine of the type shown in FIG. 17) and / or a device for partial recirculation of the exhaust gases, without departing from the scope of the invention.

In FIG. 17, an M4 compressor motor is shown two-stage that can be used both for a two-stroke engine than for a four-stroke engine. The elements of this M4 engine, which identical to those of the engines previously described, bear the same reference numbers.

Figures 18 to 25 show the different phases of the cycle of operation of a four-stroke M4 engine of the type to exhaust and intake valves and single stage compressor comprising a tilting compressor piston. Of course, the M4 engine may include one or more cylinders. The four-stroke engine operation will now be described in reference to Figures 18 to 25.

In FIG. 18, the engine piston 4 is at the end of compression, at its PMH, while the compressor piston 12 is at its PMB, that is, in its rightmost position in Figure 18. In this position, the intake valve 217 and the exhaust valve 118a are closed, as well as the suction valve 15a and the flap of repression 16a. The angular phase shift between the crankpin 8 and the eccentric 10 is of the order of 90 °, but this phase shift is more precisely calculated according to the efficiency of the compressor and filling rate of the cylinder. The position shown in Figure 18 corresponds to the ignition of the fuel mixture in the chamber of combustion.

For the position illustrated in FIG. 18, the chamber 14a of the compressor 14 is filled with fresh air, while the pipeline intake is filled with compressed hot air.

During relaxation, under the action of the combustion of gases in the combustion chamber 5, the engine piston goes down, as illustrated in FIG. 19, after a rotation of about 150.degree. crankshaft 9, which simultaneously causes the tilting of the piston of compressor 12 around its upper portion and then a start of tilting around its lower portion, thus generating a first compression in the compression chamber 14a.

As illustrated in FIG. 18, the rotation of the crankshaft 9 is done clockwise, illustrated by the arrow F.

In the position illustrated in Figure 19, the chamber of combustion 5 is filled with flue gases that are starting to escape by the exhaust manifold 118, as illustrated by the arrow F2, to following the opening of the exhaust valve 118a which is moves in its lower position as shown in Figure 19. The intake valve 15a remains closed, but the discharge valve 16a opens, allowing compressed air to be forced back into the chamber of compressor 14a to the inlet pipe 16 which already contains compressed air. Thus, supercharged air is obtained in the intake duct 16, as illustrated by the arrow F1.

At the end of relaxation, the engine piston 4 arrives at its PMB, as illustrated in Figure 20 after rotation of approximately 30 ° additional clockwise as indicated by the arrow F. In this position, the compressor piston 12 has finished tilting around its lower portion to reach its position of leftmost maximum compression in the chamber of compression 14a. The inlet valve 15a remains closed and the flap of backflow 16a remains open to finish overcompressing the air in the intake duct 16, as indicated by the arrow F1. In this position, the flue gases continue to escape through the tubing exhaust 118, in the direction of the arrow F2. We have reached here the first stage of the four-stroke cycle of the M4 engine.

During the subsequent rotation of the crankshaft 9, as illustrated in FIG. 21, the engine piston 4 during its phase of compression of the combustion chamber, just repress the burnt gases to the exhaust manifold 118. In the position illustrated on the Figure 21, the crankshaft turned about 160 ° further. In this position, the compressor piston 12 has tilted around its upper portion, then around its lower portion, to reach a detent position of the compression chamber 14a. During the expansion phase of the compressor 14, the suction valve 15a is open and the discharge valve 16a is closed, to suck air fresh, as indicated by the arrow F3 in the compression chamber 14a. At the same time, the intake valve 217 opens to admit compressed air in the combustion chamber as illustrated by the arrow F4 and drive the rest of the flue gas to the tubing exhaust. Figure 22 shows the end of the compression stroke of the engine piston 4, for which the crankshaft 9 has made a 360 ° rotation from its initial position shown in the figure 18. In this position, the suction valve 15a has closed, and the two valves 217 and 118a remain open. The arrow F4 indicates the admission of compressed hot air into the combustion chamber. The position of Figure 22 illustrates the second cycle time at four time.

To go to FIG. 23, the crankshaft 9 has rotated by one twenty additional degrees, to begin the phase of 4. In this position, the valve exhaust 118a has closed, but the intake valve remains opened. The discharge valve 16a also opens to push back the fresh air contained in the compression chamber 14a in the intake duct 16, as indicated by the arrow F1. When the engine piston 4 reaches its PMB as illustrated in FIG. 24, that is to say at the third stage of the four-stroke cycle, the combustion chamber 5 was filled with hot compressed air from, on the one hand, compressed air contained in the pipe 16 and, on the other hand, the compressed air contained in the compression chamber 14a and discharged by the compressor piston 12, since the discharge valve 16a has remained open. We have thus obtained a double filling of the combustion chamber 5.

In FIG. 25, the additional rotation of the crankshaft 9 about 30 °. In this position, the two valves 217 and 118a are closed and we get a start of air compression contained in the combustion chamber 5. The discharge valve 16a is also closed, but the inlet valve 15a is open to admit fresh air back into the compression chamber 14a. At the latest at the end of the compression stroke of the engine piston 4, the fuel can be injected into the combustion chamber 5. Then, the engine piston 4 reaches its TDC, as illustrated in FIG. 18.

Although this is not represented, the different engines of the invention may be equipped with injectors, for direct injection or indirect use of gasoline or diesel, or work with blends précarburés.

Finally, in FIG. 16, a four-motor M is shown cylinders 1 in line, comprising four compressors 14 of the single-stage type tilting compressor piston, whose rods 11 are offset from the axis of the respective cylinder, the compressors 14 being arranged alternately on each lateral face of the cylinder block 2.

Of course, the invention also applies to all types of motors, mono or poly-cylinders, in line or in V.

Although the invention has been described in connection with several particular embodiments, it is quite obvious that it is not not limited and includes all technical equivalents described means as well as their combinations if these enter in the context of the invention.

Claims (15)

1. Two-stroke or four-stroke internal combustion engine (M, M1, M2, M3, M4), operating by admitting a carburated mixture or by admitting fresh air with the direct or indirect injection of fuel, the engine having at least one cylinder (1) defining a variable-volume combustion chamber (5) in which an engine piston (4). coupled by a connecting rod (7) to the wrist pin (8) of a crankshaft (9) executes a reciprocating movement, and a compressor (14) associated with each cylinder in order to supercharge the cylinder with carburated mixture or with fresh air, said compressor (14) including at least one stage, in the compression chamber (14a, 14b) of which there moves a compressor piston (12, 112, 212) which is coupled to the crankshaft (9) by a link rod (11, 111) articulated to an eccentric (10), said eccentric being mounted on the shaft of said crankshaft (9), the compressor piston (112, 212) being secured at its centre to a rod (121) articulated to the link rod (111) for connection to the eccentric (10), said rod being guided in translation in a direction which intersects the axis of the cylinder (1), the compressor piston being a deformable diaphragm (212) connected at its periphery to the side wall of the compression chamber, the angle between the axis of the cylinder and the axis of the compression chamber being of 90°, characterized in that the angle () of the dihedron, the solid angle of intersection of which is formed by the axis of the crankshaft (9) and the two half-planes of which extend one towards the eccentric (10) and the other towards the wrist pin (8), is of the order of 90° so as to obtain a phase shift of 180° between the top dead centre (PMH) positions of the engine piston (4) and of the compressor piston (12, 112, 212) which are associated with the same cylinder, which phase shift ensures that the pressure in the compression chamber (14a, 14b) is at its maximum before the carburated mixture or the fresh air is admitted into the combustion chamber (5).
2. Engine according to Claim 1, characterized in that when the stage (14b) of the compression chamber which communicates directly with the cylinder (1) is located between the compressor piston (112, 212) and the crankshaft (9), the wrist pin (8) has a phase shift in advance of the eccentric (10) in the direction of rotation (F) of the crankshaft and, conversely, when the aforementioned stage (14a) is on the opposite side of the compressor piston (12, 112, 212) to the crankshaft, the eccentric has a phase shift in advance of the wrist pin in the direction of rotation of the crankshaft.
3. Engine according to either of Claims 1 and 2, characterized in that the cylinder capacity of the compressor (14) is of the order of magnitude of that of the cylinder (1), but with a compressor piston (12, 112, 212) which has a diameter markedly greater than the diameter of the engine piston (4), so that the compressor piston has a short compression stroke (C) in the compression chamber.
4. Engine according to one of Claims 1 to 3, characterized in that said diaphragm has an undulation (212a) at its periphery, to make it easier to deform.
5. Engine according to one of Claims 1 to 4, characterized in that the compression chamber has two stages (14a, 14b) located one on each side of the compressor piston (112, 212), a first stage (14a or 14b) being supplied with carburated mixture or with fresh air by a first nonreturn valve (115a) or a valve, and connected by a delivery duct (130) fitted with a second nonreturn valve (130a) or a valve to the second stage (14b or 14a) which communicates with the cylinder (1) via an inlet duct (16) possibly fitted with a third nonreturn valve (16a) or a valve.
6. Two-stroke internal combustion engine according to one of Claims 1 to 5, characterized in that it is equipped with an additional volume (40, 140) communicating with the cylinder (1) through closure and opening means (42, 44; 142, 144), the movements of which are controlled either in synchronism or with a phase shift with respect to those of the engine piston (4) in the cylinder so that during the expansion phase, the burnt gases compress the air in the additional volume and at least partially enter it, so that this air and burnt gases mixture is trapped under pressure therein, and then so that this mixture is admitted into the cylinder during the compression phase.
7. Engine according to Claim 6, characterized in that after the air and burnt gases mixture previously trapped in the additional volume (40, 140) has been admitted into the cylinder (1), said additional volume is once again filled with fresh air from the compressor (14).
8. Engine according to Claim 6 or 7, characterized in that the aforementioned closure and opening means comprise two rotary shutters (42, 44; 142, 144), for example multi-way rotary spools, connected to each other by the additional volume (40, 140), one (42, 142) of the shutters being associated with the compressor (14), and the other shutter (44, 144) being associated with the exhaust from the cylinder (1).
9. Engine according to Claim 8, characterized in that the two rotary shutters are arranged in such a way that the following operations take place: in a first phase, when the engine piston (4) is near its PMH, a flow of air from the compressor (14) passes through the lower shutter (42, 142) associated with the compressor, sweeps through the additional volume (40, 140), passes through the upper shutter (44, 144) associated with the exhaust and is exhausted to the outside via an exhaust manifold; in a second phase, from about halfway through the expansion stroke of the engine piston, on the one hand, the upper shutter (44, 144) places the cylinder (1) in communication with the additional volume so as to fill it with a pressurized mixture of air and burnt gases and, on the other hand, the cylinder communicates with the exhaust; in a third phase, the upper shutter traps the air and burnt gases mixture in the additional volume; in a fourth phase, air from the compressor (14) is admitted into the cylinder and, in a fifth phase, at the start of the engine piston compression stroke, the trapped and pressurized mixture is admitted into the cylinder.
10. Engine according to Claims 9, characterized in that the upper shutter (44) is connected to the cylinder (1) by a pipe (45) arranged towards the bottom of the cylinder and the lower shutter (42) is fitted on the delivery pipe (130) between the two stages (14a, 14b) of the compressor (14) so that the additional volume (40) is pressurized by means of the burnt gases from the cylinder (1) through the upper shutter (44) and is emptied into the cylinder through the pipe (45) connected to the upper shutter.
11. Engine according to Claim 9, characterized in that the upper shutter (144) is associated with at least one exhaust valve (118a) located at the top of the cylinder (1) and the lower shutter (142) is connected to the cylinder (1) by a pipe (141) arranged towards the bottom of the cylinder so that the additional volume (140) is pressurized via its upper end by the burnt gases from the exhaust valve (118a) through the upper shutter (144) and is emptied into the cylinder via its lower end through the lower shutter (142).
12. Engine according to one of Claims 1 to 10, characterized in that it is of loop scavenging type (M1), in which the carburated mixture or the fresh air is admitted from the compressor (14) through an inlet duct (16) opening via ports (17) into the lower part of the cylinder (1) with an orientation such that the mixture or the air is introduced with a looping upward rotating movement, while the burnt gases from the previous cycle are discharged through exhaust ports (8) also arranged towards the bottom of the cylinder.
13. Engine according to one of Claims 1 to 9 and 11, characterized in that it is of the uniflow type (M2), in which the carburated mixture or the air is admitted towards the bottom of the cylinder (1) through inlet ports distributed at the base of the cylinder and supplied by a ring (117), itself connected to the compressor (14), while the burnt gases from the previous cycle are discharged through one or more exhaust valves (118a) located at the top of the cylinder.
14. Two-stroke internal combustion engine according to one of Claims 1 to 9 and 11, or four-stroke internal combustion engine according to one of Claims 1 to 5, characterized in that it is of the type with exhaust and inlet valves (M3, M4), in which the valves (118a, 217) are located at the top of the cylinder (1) and the inlet valve or valves (217) are supplied by the compressor (14).
15. Engine according to one of Claims 1 to 14, characterized in that it is of the type with several in-line cylinders (M), in which the compressors (14) associated with each cylinder (1) are arranged alternately on each face of the crankcase (2).

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