EP1018597A1 - Charged two or four stroke internal-combustion engine - Google Patents

Abstract

The engine has at least one cylinder with a combustion chamber and a piston (4) connected by a rod (7) to a crankshaft (9). Each cylinder is supercharged with air or a combustible mixture by a compressor (14) with at least one stage containing a piston (112). The compressor piston is connected to the crankshaft (9) by an arm (11) pivoted to a cam (10) mounted on the crankshaft so that there is a 90-degree difference in the engine and compressor piston phases.

Description

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

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

We already know a two-stroke single-cylinder engine that works by natural suction in the cylinder of a mixture fuel which passes through the cylinder crankcase. This engine has a air / fuel mixture intake pipe and one pipe exhaust of the burnt gases, both of which lead to lights in the lower part of the cylinder, near the bottom dead center (PMB). The fuel mixture from the carburetor is drawn into the casing through a valve, during the ascending phase of the piston which creates a vacuum in the casing, then is driven back to the cylinder, during the descending phase of the piston generating a overpressure in the housing. During the descending phase of the piston, the mixture 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 high pollution atmospheric. The main advantage of this engine is its low cost, but the new anti-pollution standards ultimately condemn this type engine.

Another known motor is of the loop scanning type, which works with a positive displacement compressor, for example of the type Roots, to facilitate the introduction of the fuel mixture into the cylinder and cause a low pressure boost. This engine has also a mixture inlet pipe and a pipe exhaust pipes, both of which lead through 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 a rotational movement ascending in a loop, like a looping, in the cylinder, while the gases burned from the previous cycle are evacuated by the exhaust lights. The particular arrangement of the lights intake and exhaust allows not to send directly towards the exhaust part of the admitted mixture, which reduces both consumption and environmental pollution.

Yet another known engine is of the "uniflow" type which also works with a positive displacement compressor. This engine has an intake pipe connected upstream to the compressor and downstream to an intake ring which opens by a plurality of lights in the lower part of the cylinder, with an orientation such that the mixture is introduced with a significant rotational movement. The burnt gases are evacuated in the upper part of the cylinder through one or several exhaust valves. This type of motor allows check the filling of the cylinder and the possible recycling of gases burned, to obtain a less polluting 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 air rotation, which is necessary for good performance. This engine consumes even less fuel than the loop scanning motor and also reduces polluting emissions to the outside.

However, these latter two types of motor have a cost well higher than 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 of Roots type have low efficiency, for example a motor two-stroke single cylinder with a displacement of one liter and a 55kW power, will consume 17kW to drive the compressor. In addition, a Roots compressor does not work beyond a pressure greater than 1.2 bars.

We finally know the engine with exhaust valves and intake, which provides the lowest consumption and lowest 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 organs to the cylinder, allows to use the whole stroke of the piston, whereas with the previous engines where the admission takes place by lights, part of the compression stroke and the stroke relaxation is lost.

The object of the invention is to propose a motor compressed to two- or four-stroke internal combustion, for example of the loop, uniflow or valve, or four-stroke valves, which improves performance and reduces polluting emissions.

To this end, the invention relates to a combustion engine internal two- or four-stroke, operating by admission of fuel mixture or by fresh air intake with direct injection or indirect fuel, the engine comprising at least one cylinder defining a variable volume combustion chamber, in which alternately moves a motor piston which is coupled by a crankpin connecting rod of a crankshaft, and an associated compressor to each cylinder to obtain a cylinder overfeeding fuel or fresh air mixture, characterized in that said compressor is a compressor comprising at least one stage, in the compression chamber from which a compressor piston moves, which is coupled to the crankshaft by a link articulated on a eccentric, said eccentric being mounted on the shaft of said crankshaft.

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

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

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

In a particular embodiment, the piston of compressor is rigidly fixed in its center to the connecting rod with the eccentric, so that the compressor piston moves in the compression chamber by alternating tilting around the lower and upper parts of the compression chamber, the axis of the compressor being offset, in the direction of the crankshaft axis, by relative to the axis of the cylinder. In this case, the compressor piston can have at its periphery a spherical border provided with a segment spherical seal which is preferably stationary in rotation by relative to the compressor piston, in a position such as the slot of the segment is not placed in the lower part of the compressor, to limit oil consumption and therefore pollution of the environment.

In another embodiment, the compressor piston is secured in its center by a rod articulated to the connecting rod with the eccentric, said rod being guided in translation in one direction which intersects the axis of the cylinder. In a first variant, the piston compressor is a deformable membrane connected at its periphery to the side wall of the compression chamber, said membrane preferably having a ripple at its periphery to facilitate its deformation. In a second variant, the compressor piston is a rigid cylinder displaceable in axial translation and provided at its periphery of at least one sealing segment.

This second embodiment is advantageous in that it poses no risk of oil passing between the crankcase and the compressor compression chamber, because it is possible to have a seal or bellows on the piston rod of the compressor.

In a particular embodiment, the compression is two stages located on either side of the piston compressor, a first stage being supplied with a fuel mixture or fresh air by a first non-return valve or a valve, and connected by a discharge pipe fitted with a second non-return valve or a valve, on the second stage which communicates with the cylinder by an intake manifold possibly fitted with a third valve check valve or valve. The use of a two compressor stages provides 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 which is incompatible with the mechanical strength of the cylinder. The engine fitted with this two-stage compressor will operate analogously to the known type supercharging system hyperbar.

The two-stroke engine of the invention can also be equipped with a device to recover energy from puffs exhaust and partial exhaust gas recirculation in providing an additional volume communicating with the cylinder to through shutter and opening means, the movements of which are controlled synchronously or out of phase with those of the piston engine in the cylinder, so that, during the expansion phase, the burnt gases compress the air in the additional volume by entering it at least partially, that this mixture of air and burnt gases is trapped there under pressure, then this mixture is admitted into the cylinder during the compression phase.

Advantageously, after the mixture of air and burnt gases previously trapped in the additional volume, has been admitted in the cylinder, said additional volume is again filled with fresh air by from the compressor.

According to another characteristic, the sealing means and opening aforementioned comprise two rotary shutters, for example multi-way rotary valves, interconnected by the additional volume, one of the shutters being associated with the compressor and the other shutter at the cylinder exhaust.

Preferably, the two rotary shutters are arranged so that the following operations take place: in a first time, when the engine piston is near its TDC, a air flow from the compressor through the lower shutter associated with the compressor, sweeps the additional volume, crosses the upper shutter associated with the exhaust and escapes towards the exterior by an exhaust manifold; in a second time, from about half the trigger stroke of the engine piston, on the one hand, the upper shutter connects the cylinder with the additional volume to fill it with an air and gas mixture burned under pressure, and on the other hand, the cylinder communicates with the exhaust; thirdly, the upper shutter traps the mixture of air and burnt gases in the additional volume; in one fourth step, air from the compressor is admitted to the cylinder, and in a fifth step, at the start of the compression of the engine piston, the trapped and pressurized mixture 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 put under pressure by its upper end by means of the burnt gases from the exhaust valve through the shutter upper, and is emptied into the cylinder by its lower end at through the lower shutter.

In a second variant, the upper shutter is connected to the cylinder by a pipe arranged in the lower part 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 is put under pressure by means of burnt gases from from the cylinder through the upper shutter and is emptied into the cylinder by the pipe connected to the upper shutter.

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

The two-stroke engine can be of the loop scanning type, into which the fuel mixture or fresh air is admitted from compressor by an inlet manifold opening through lights in the lower part of the cylinder with an orientation such as mixing or the air is introduced with an upward rotation movement in a loop, while the gases burned from the previous cycle are evacuated by exhaust lights also arranged in the lower part of the cylinder.

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

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

The invention also applies to an engine of the type with several in-line cylinders, in which the compressors associated with each cylinder are arranged alternately on each side of the housing cylinder.

To better understand the object of the invention, we will describe now, by way of purely illustrative examples and not restrictive, several embodiments shown in the drawing Annex.

• la figure 1 est une vue schématique en coupe verticale d'un premier mode de réalisation 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, 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 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 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 selon 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 schematic view in vertical section of a first embodiment of the engine of the invention, of the two-stroke type with loop scanning, with single-stage compressor and with tilting compressor piston with a partial enlargement of this last ;
• FIGS. 2A to 2D are partial views similar to FIG. 1 and in vertical section along line II in FIG. 3, representing respectively the engine piston at its TDC, during expansion, at its TDC and during compression , for a two-stroke engine;
• Figure 3 is a sectional view along line III of Figure 2A;
• Figure 4 is a view similar to Figure 1, but according to a variant in which the compressor piston is linearly displaced, 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 showing another variant, in which the compressor piston is a deformable membrane and the cylinder is equipped with a spark plug;
• Figures 6A to 6D are sectional views along line VI of Figures 5A to 5D respectively, with a partial enlargement of said membrane in Figure 6A;
• Figure 7 is a sectional view along line VII of Figure 5A;
• Figure 8 is a view similar to Figure 4, but showing a two-stroke engine with two-stage compressor;
• Figure 9 is a view similar to Figure 8, but showing the two-stroke engine further equipped with a partial exhaust gas recirculation system;
• Figures 10 and 11 are views similar to Figures 1 and 4 respectively, but show a second embodiment of the two-stroke engine of 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;
• Figure 13 is a view similar to Figure 12, but showing the two-stroke engine further equipped with an energy recovery system of 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 of the invention, of the type with exhaust and intake valves;
• Figure 16 is a schematic top view of a four-cylinder in-line engine according to 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 sectional views, 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 analogous will bear the same reference numbers.

Figures 1 to 9 show various variants of the invention applied to a two-cylinder single-cylinder M1 internal combustion engine time and loop scan.

In the first variant shown in Figures 1 to 3, the engine M1 comprises a cylinder 1 defined between the cylinder block 2 and the cylinder head 3 of the engine. The cylinder head 3 has an obviously 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 just as well to a direct injection diesel engine or indirect.

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

An eccentric 10 is mounted on the crankshaft 9 and articulated on a link 11 which is rigidly fixed in the center of a compressor piston 12 in the shape of a disc. The piston of compressor 12 has at its periphery a spherical border 12a provided with a sealing segment 13 also having a spherical border, which is immobilized in rotation relative to the compressor piston, in a position such that the segment 13 slot is not placed in lower part of the casing 2. The compressor piston 12 moves alternately by tilting inside the chamber compression 14a of a single-stage compressor 14 attached to the casing 2. The compression chamber 14a of the compressor 14 is supplied with fuel or fresh air mixture via a suction line 15 fitted 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 fitted with a non-return discharge valve 16a. The intake pipe 16 opens at the bottom of the cylinder 1 by a plurality of lights 17 which have such an orientation that the mixture or the air under pressure is introduced with a movement of rotation ascending 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 into the lower part of the cylinder, substantially at the same level as the intake lights 17.

As shown in Figure 1, the eccentric 10 is offset by angle  of the order of 90 ° relative to the crank pin 8, in the direction of rotation of the crankshaft, as indicated by arrow F, so that the TDC of engine piston 4 is 90 ° out of phase with TDC of the compressor piston 12. Referring to FIG. 3, it can be seen that the axis of the link 11 of the compressor 14 is offset by a distance d relative to the axis of the connecting rod 7 of the engine piston 4.

The displacement of cylinder 1 is substantially of the same order of size than the displacement of compressor 14, but the piston of compressor 12 has a diameter significantly larger than that of the engine piston 4, so that the compression stroke c of the piston compressor 12 is relatively small.

Finally, the intake pipe 16 can be provided with a heat exchanger 19, conveying a refrigerant, for example from water or fresh air can be blown for a air cooling, to cool the air leaving the compressor 14, which increases the mass of air admitted into cylinder 1, all the more so as the compression of the air in the compressor 14 gives off 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 crankshaft 9 is provided opposite the big end 7b a counterweight 20 which serves as a counterweight.

The broken lines in FIG. 1 indicate the TDC and TDC positions of the engine piston 4.

The path has also been indicated in dashed lines in FIG. 1. eccentric 10 and the crankpin path 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 TDC, while the compressor piston 12 is at its TDC, that is to say in its rightmost position in Figure 2A. Being trigger, under the action of the combustion of gases in the combustion 5, the engine piston goes down, as illustrated in the figure 2B, after a rotation of approximately 90 ° of the crankshaft 9, which causes simultaneously tilting the compressor piston 12 around its upper portion, thus generating a first compression in the compression chamber 14a. At the end of expansion, the engine piston 4 arrives at his PMB, simultaneously discovering the tubing exhaust 18 and intake lights 17, after rotation additional 90 ° of the crankshaft 9. Simultaneously, the piston of compressor 12 swings around its lower portion to reach its leftmost maximum compression position in the chamber of compression 14a, which causes the admission of air or fuel mixture under pressure in the combustion chamber 5, thus driving the burnt gases towards the exhaust and filling the cylinder. In FIG. 2D, the engine piston has been represented during of its compression phase, after an additional 90 ° rotation of the 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 compression 14a, the fresh air or the fuel mixture being sucked in by the suction line 15, due to the vacuum thus generated in room 14a. Finally, when the engine piston 4 reaches its TDC illustrated in Figure 2A, after an additional 90 ° rotation of the crankshaft 9, the compressor piston 12 rocks around its lower portion, to bring it back to its rightmost position, fresh air or the fuel mixture thus continuing to be drawn into the compression chamber 14a. The coming operating cycle to be described is thus repeated successively.

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

However, due to the alternating tilting of the piston compressor 12, there is a risk that the oil contained in the crankcase passes into the compression chamber 14a, causing a oil consumption and environmental pollution due to the fact that the oil is thus discharged to the outside.

This drawback is eliminated in the variant illustrated on the Figures 4 to 7, where the tilting compressor piston 12 is replaced by a compressor piston 112 illustrated in FIG. 4 which moves alternately in linear translation in the compression chamber 14a.

This compressor piston 112 also has at its periphery a sealing segment and comprises in its center a rod 121 rigidly fixed to the compressor piston 112 and articulated at its free end to the link 11 connecting with the eccentric 10. The rod 121 is guided in translation by a guide sleeve 122 which is connects to the casing 2 by a vertical partition 123. The sleeve 122 can be fitted internally with a sealing ring through which the rod 121, or alternatively a sealing bellows S can be connected between the rod 121 and said vertical partition 123, which removes all 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, a spark plug 22 is arranged.

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

As best seen in Figures 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 to the eccentric is thus formed by the assembly of the cross member 124 and two arms 111. The two arms 111 of the link are each mounted on a disc 10 which is respectively mounted eccentrically on the shaft 9 of the crankshaft between the side wall of the casing 2 and an arm of the crankpin 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 eccentric disc 10, and at shaft level crankshaft 9. However, if the rotation is slow enough, these bearings can be replaced by ball bearings or by slip rings.

As shown in Figure 7, in this case, the axis of the piston 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 compressor is mounted with a stick 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 engine piston 4 is at TDC, and the diaphragm is deformed into bending to the right towards the crankshaft. In Figure 5B, the engine piston is halfway in its expansion phase, and the membrane 212 is in a substantially flat, vertical position. Sure FIG. 5C, the engine piston 4 is at its PMB, and the membrane 212 is deformed in flexion to the left, opposite the crankshaft. Finally, in FIG. 5D, the engine piston 4 is halfway in its upward compression stroke, and the membrane 212 is again in a flat position, at rest.

By way of example, the engine shown in Figures 5 to 7 comprises a cylinder 1 having a diameter of approximately 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 compressor piston 212.

The variant illustrated in Figure 8 differs from the variant represented in FIG. 4, essentially by the fact that the 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 has in the upper part a suction pipe 115 provided with a non-return 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, an intermediate discharge pipe 130 is provided which communicates in the lower part of the second stage 14a of the compressor 14. This intermediate discharge line 130 is provided with a non-return valve 130a and a cooling system 19. The second stage 14a of compressor 14 communicates in the upper part with the intake manifold 16, similar to the compressor single-stage described in Figures 1 to 7.

The various valves 115a, 130a and 16a of the compressor 14 and the engine valves 118a and 217 can advantageously be replaced by mechanically or electronically controlled valves, or hydro-electronics, which can be managed by a computer digital, in order to control all motor parameters on demand, know the compression ratio in the compressor and / or in the engine cylinder, as well as expansion rates.

Although Figure 8 shows a compressor piston 112 in rigid flat disc 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 air delivery, via line 130, to the second stage 14a. During the downward expansion phase of the engine piston 4, the compressor piston 112 moves to the left, causing overcompression of the air contained in the second stage 14a, which does not can go back through line 130, due to the non-return valve 130a, and therefore escapes towards the intake pipe 16 to a pressure higher than that which would be obtained with a compressor single-stage. Simultaneously, depression is generated in the first stage 14b, which causes the suction of air from the suction pipe 115.

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

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

An additional volume 40, which can have any suitable form, communicates in the lower part with a pipe 41 which leads to a rotary shutter 42, for example, a three-way rotary plug tracks, which is interposed on the above-mentioned discharge line 130, 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 plug turning in three ways, the latter communicating, on the one hand, by a pipe 45 in the lower part of cylinder 1, and, on the other hand, by a line 46, with an exhaust manifold (not shown) connected to the aforementioned exhaust pipe 18.

We will now describe the operation of the illustrated motor in figure 9.

When the engine piston 4 comes close to its TDC, in the compression phase, the lower plug 42 communicates the first stage 14b of compressor 14 with line 41, while closing the passage to the second stage 14a, while the plug upper 44 connects line 43 with line exhaust 46, while closing the passage to the pipe 45 which opens into the lower part of 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 balance of the air and burnt gas mixture in this volume 40 thus being evacuated to the outside and replaced by fresh air.

Then, at the start of the expansion phase of the engine piston 4, shown in Figure 9, the plugs 42 and 44 close all communication, the rotation of the bushels being able to be controlled with the rotation of the crankshaft 9, or else controlled by a central unit of electronic management.

When the engine piston 4 substantially reaches the end of trigger, the engine piston 4 discovers the opening of the pipeline 45 and the combustion gases being under pressure in cylinder 1 then escape through this pipe 45 and pass through the shutter 44 up to additional volume 40, the upper shutter 44 being in a position for closing the exhaust pipe 46. Simultaneously, the shutter 42 closes the passage of the pipe 41, so that the burnt gases compress the air in the additional volume 40 and partially penetrate it.

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 burnt gases, which are expelled 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 BDC, the upper plug 44 blocks all communication and the lower plug 42 opens the passage between the first and the second stage of the compressor, while now closed the passage to line 41, so that the pressurized mixture of air and burnt gases, which was in the volume additional 40 is thus trapped there. At PMB, the scanning of cylinder 1 is finishes and the latter begins to fill with fresh air at high pressure delivered by the compressor 14.

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

When the engine piston 4 exceeds about halfway through its ascending phase, the exhaust pipe 18 and the pipe 45 are closed by the engine piston 4 and the valves 44 and 42 are gradually move to the position that ports the first stage 14b of the compressor with the exhaust 46.

Note that, in this case, the two-stage compressor 14 has lower efficiency than in Figure 8, because part of the compression stroke of the first stage 14b of the compressor 14 is used to scan 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 Figures 10 to 12 correspond to the variants represented in FIGS. 1, 4 and 8 of the loop scanning motor. Under these conditions, the operation of the uniflow M2 motor will be described only once for all of these three variants.

In a uniflow engine, as shown in Figure 10, the intake pipe 16 opens onto an annular ring 117 surrounding the lower part of the cylinder 1, said ring 117 having a plurality of lights (not shown) which partially open bottom of 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 cylinder 1 and has at least one valve 118a which is controlled by any adapted means.

When the engine piston 4 is at its TDC, the one or more exhaust valves 118a are closed, as well as the lights which are blocked by the body of the engine piston 4. In end of expansion of the engine piston 4, the exhaust valve (s) 118a open, to evacuate the burnt gases, and the engine piston 4 uncovers the lights on the intake crown 117, so that the compressed air coming from the compressor 14 pushes up the gases burned towards the exhaust. The filling of cylinder 1 in combustion air continues until the compression piston begins engine 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 to recover energy from puffs exhaust and partial exhaust gas recycling. This device has an additional volume 140 which is formed by a adapted section pipe communicating at both ends with a rotary shutter 142, 144 which may be constituted by a multi-way rotating bushel. The upper bushel 144 communicates, in addition, with the exhaust pipe 118, downstream the exhaust valve (s) 118a provided at the top of the cylinder 1, and with two other pipes 145 and 146 which terminate to an exhaust manifold not shown.

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

The rotary movements of the plugs 142, 144 are linked by any suitable way, known to those skilled in the art and therefore not described, to the rotary movement of the crankshaft 9, in 1/1 ratio or different from 1/1, phased or phase-shifted relative to the movement of the crankshaft.

Furthermore, in FIG. 13, the positions of the two stages 14a and 14b of compressor 14 are reversed with respect to the piston of compressor 112. In fact, the intake pipe 16 communicates with 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 crankshaft 9, is supplied with air fresh via the suction line 115. As a result, the operation of compressor 14 is reversed, and crankpin 8 of crankshaft must be phase shifted by an angle  of about 90 ° relative 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 which are possibly provided, are closed as well as plugs 142 and 144.

During the expansion phase of the engine piston 4, the one or more exhaust valves 118a open and the upper shutter 144 swivels, for example in the same direction as the crankshaft 9, to make communicating the exhaust pipe 118 with the pipe 140 forming the additional volume. The lower bushel 142 has also turned the same amount in the same direction, but this did brought no connection of pipes. The result a puff of burnt gas under pressure is discharged via the exhaust pipe 118 in pipe 140, which compresses the air therein, while introducing a portion of gas therein burned, corresponding to the angular period of transfer.

When the engine piston 4 reaches an intermediate position between the pipe 141 and the intake ring 117, the one or more 118a exhaust valves are still open, but the plug 144 having turned connects lines 118 and 145, while closing the passage to line 140; bushel lower 142 also rotated, but without setting communication. As a result, the air / burnt gas mixture, which has been previously introduced under pressure (approximately 3.5 bar at full charge) in line 140, is trapped there and the burnt gases escape through line 145 to the exhaust manifold.

When the engine piston 4 reaches its PMB, the shutter superior 144, although having continued to rotate, maintains the communication between lines 118 and 145; the shutter lower 142 also rotated, but without setting communication; the intake crown lights 117 are unmasked. As a result, the air coming from stage 14b of the compressor 14 performs a sweep which evacuates the burnt gases through the exhaust valve (s) 118a and the cylinder 1 is filled with air at the relatively high pressure of compressor 14. The mixture air / burnt gas is still trapped under pressure in line 140.

When the engine piston 4 begins its compression, it closes the lights on the intake crown 117 and is flush with line 141; shutter 142 having continued to rotate, lines 118 and 145 may still be communicating, but this has no effect because the valve (s) exhaust 118a are closed; the lower bushel 142 puts in communication line 141 with line 140. It As a result, the air / burnt gas mixture, which was trapped under pressure in this pipe 140 escapes and fills the cylinder 1 under pressure. This achieves both cylinder overfeeding and partial recirculation of the burnt gases, an operation known as EGR (Exhaust Gas Recirculation), which has the effect of reducing low-speed nitrogen oxide emissions.

When the engine piston 4 continues to compress, up to close the line 141, the exhaust valve (s) 118a remain closed, and the plugs 142, 144 pivot in a position where all communications are prohibited.

When the engine piston 4 substantially reaches the end of compression, the exhaust valve (s) 118a remain closed, but the upper plug 144 connects the pipe 140 with line 146; the lower bushel 142 puts in communication the line 140 with the intake line 16. As a result, the fresh air coming from the compressor 14 borrows the lines 16, 140 and 146 to evacuate the residual air / gas mixture burned in line 140 to the outside.

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

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

Figures 14 and 15 show two variants which correspond to the variants of FIGS. 10 and 11 of the M2 motor 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 one or more intake valves 217 are provided. The operation of this type of engine is analogous to the previous ones.

Although the two variants of FIGS. 14 and 15 include a single-stage compressor, we could also provide a two-stage compressor (see motor of the type shown in Figure 17) and / or a device for partial recirculation of exhaust gases, without departing from the scope of the invention.

In FIG. 17, an M4 compressor motor has been represented. two-stage which can be used as well for a two-stroke engine than for a four-stroke engine. The elements of this M4 engine, which are identical to those of the motors described above, bear the same reference figures.

In Figures 18 to 25, the different phases of the operating cycle of an M4 type four-stroke engine single-stage exhaust and intake and compressor valves comprising a tilting compressor piston. Of course, the M4 engine can have one or more cylinders. The operation of the four-stroke engine 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 TDC, while the compressor piston 12 is at its TDC, 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 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 the cylinder filling rate. The position illustrated in figure 18 corresponds to the ignition of the fuel mixture in the 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 hot compressed air.

During expansion, under the action of the combustion of gases in the combustion chamber 5, the engine piston goes down, as illustrated in figure 19, after a rotation of approximately 150 ° of the crankshaft 9, which simultaneously causes the piston to tilt of compressor 12 around its upper portion, 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 carried out clockwise, illustrated by arrow F.

In the position illustrated in Figure 19, the combustion 5 is filled with burnt gases that begin to escape by the exhaust manifold 118, as illustrated by the arrow F2, at following the opening of the exhaust valve 118a which is moves to its low position as shown in Figure 19. The inlet valve 15a remains closed, but the outlet valve 16a opens, allowing compressed air to be forced back into the compressor 14a to the inlet pipe 16 which already contains compressed air. Thus, one obtains supercharged air in the intake pipe 16, as shown by arrow F1.

At the end of expansion, the engine piston 4 arrives at its PMB, as illustrated in figure 20 after rotation of approximately 30 ° 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 compression 14a. The inlet valve 15a remains closed and the discharge 16a remains open to finish over-compressing the air in the intake pipe 16, as indicated by arrow F1. In this position, the burnt gases continue to escape through the tubing exhaust 118, in the direction of arrow F2. Here we have reached first time 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, expels the burnt gases to the exhaust manifold 118. In the position illustrated in the figure 21, the crankshaft has rotated by an additional 160 °. In this position, the compressor piston 12 has tilted around its upper portion, then around its lower portion, to reach an expansion 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 in air fresh, as indicated by arrow F3 in the compression chamber 14a. Simultaneously, the intake valve 217 opens to admit the compressed air in the combustion chamber as illustrated by the arrow F4 and thus expel the rest of the burnt gases towards the manifold 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 illustrated 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 time of the cycle with four time.

To pass to FIG. 23, the crankshaft 9 has pivoted by one twenty additional degrees, to start the phase of expansion of the engine piston 4. In this position, the valve 118a has closed, but the intake valve remains opened. The discharge valve 16a also opens to discharge the fresh air contained in the compression chamber 14a in the intake pipe 16, as indicated by arrow F1. When the engine piston 4 reaches its BDC as illustrated in FIG. 24, that is to say during the third step of the four-stroke cycle, the combustion chamber 5 has been filled with hot compressed air on the one hand, from the compressed air contained in the pipeline intake 16 and, on the other hand, 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 of about 30 °. In this position, the two valves 217 and 118a are closed and the start of air compression is obtained 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 engine piston compression stroke 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 it is not shown, the different engines of the invention can be fitted with injectors, for direct injection or indirect petrol or diesel, or work with mixtures precarburized.

Finally, in FIG. 16, a motor M has been represented with four cylinders 1 in line, comprising four compressors 14 of the single-stage type with tilting compressor piston, the links 11 of which are shown off-axis with respect to the axis of the respective cylinder, the compressors 14 being arranged alternately on each side face of the cylinder block 2.

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

Although the invention has been described in connection with several particular embodiments, it is obvious that it is not there in no way limited and that it includes all technical equivalents means described as well as their combinations if these enter in the context of the invention.

Claims (19)

Two or four-stroke internal combustion engine (M, M1, M2, M3, M4), operating by admitting fuel mixture or by admission of fresh air with direct or indirect injection of fuel, the engine comprising at least one cylinder (1) defining a variable volume combustion chamber (5), in which alternately moves a motor piston (4) which is coupled by a connecting rod (7) to the crankpin (8) of a crankshaft (9), and a compressor (14) associated with each cylinder to obtain a cylinder overfeed in a fuel mixture or in fresh air, characterized in that said compressor (14) is a compressor comprising at least one stage, in the compression chamber (14a, 14b) from which a piston moves compressor (12, 112, 212), which is coupled to the crankshaft (9) by a link (11, 111) articulated on an eccentric (10), said eccentric being mounted on the shaft of said crankshaft (9), and in that the angle () the dihedral, the edge of which is formed by the axis of the crankshaft (9) and whose two half-planes extend respectively towards the eccentric (10) and the crankpin (8), is of the order of 90 ° to obtain a phase shift between the top dead center (TDC) of the engine piston (4) and the piston compressor (12, 112, 212) associated with the same cylinder, phase shift which ensures maximum pressure in the compression chamber (14a, 14b) before admitting the fuel mixture or fresh air into the combustion chamber (5). Motor 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 piston of compressor (112, 212) and the crankshaft (9), the crankpin (8) is phase shifted ahead of the eccentric (10) in the direction of rotation (F) of the crankshaft, and vice versa, when the aforementioned stage (14a) is located on the opposite side of the compressor piston (12, 112, 212) at the crankshaft, the eccentric is out of phase with respect to the crankpin in the direction of rotation of the crankshaft. Motor according to one of claims 1 and 2, characterized by fact that the displacement of the compressor (14) is of the order of magnitude of that of the cylinder (1), but with a compressor piston (12, 112, 212) having a diameter significantly greater than the diameter of the piston motor (4), to obtain a small compression stroke (C) of the compressor piston in the compression chamber. Motor according to one of Claims 1 to 3, characterized by the causes the compressor piston (112, 212) to be fixed in its center a rod (121) articulated to the connecting rod (111) with the eccentric (10), said rod being guided in translation in a direction which intersects the cylinder axis (1). Motor according to claim 4, characterized in that the compressor piston is a deformable membrane (212) connected to its periphery to the side wall of the compression chamber, said membrane preferably comprising an undulation (212a) at its periphery to facilitate its deformation. Motor according to claim 4, characterized in that the compressor piston is a rigid cylinder (112) movable in axial translation and provided at its periphery with at least one segment sealing. Motor according to one of Claims 1 to 3, characterized by the causes the compressor piston (12) to be rigidly fixed at its center to the connecting rod (11) with the eccentric (10), so that the compressor piston moves in the compression chamber (14a) by alternating tilting around the lower parts and top of the compression chamber, the axis of the compressor (14) being offset, in the direction of the axis of the crankshaft (9), relative to the axis of the cylinder (1). Motor according to claim 7, characterized in that the compressor piston (12) has a border at its periphery spherical (12a) provided with a spherical sealing segment (13) which is preferably stationary in rotation relative to the piston of compressor, in a position such that the segment slot is not placed in the lower part of the compressor (14). Motor according to one of Claims 1 to 6, characterized by the the fact that the compression chamber has two stages (14a, 14b) located on either side of the compressor piston (112, 212), a first stage (14a or 14b) being supplied with a fuel mixture or with fresh air by a first non-return valve (115a) or a valve, and connected by a discharge pipe (130) provided with a second non-return valve (130a) or a valve, on the second stage (14b or 14a) which communicates with the cylinder (1) via an intake manifold (16) possibly fitted with a third non-return valve (16a) or a valve. Two-stroke internal combustion engine according to one of the Claims 1 to 9, characterized in that it is equipped with a volume additional (40, 140) communicating with the cylinder (1) through shutter and opening means (42, 44; 142, 144), including movements are controlled synchronously or phase shifted with those of the engine piston (4) in the cylinder, so that when expansion phase, the burnt gases compress the air in the additional volume by entering it at least partially, that this mixture of air and burnt gases is trapped there under pressure, then mixture is admitted into the cylinder during the compression phase. Motor according to claim 10, characterized in that only after the mixture of air and burnt gases previously trapped in the additional volume (40, 140), has been admitted into the cylinder (1), said additional volume is again filled with fresh air from the compressor (14). Motor according to claim 10 or 11, characterized by fact that the aforementioned closing and opening means include two rotary shutters (42, 44; 142, 144), for example multi-way rotary valves, interconnected by volume additional (40, 140), one (42, 142) of the shutters being associated with the compressor (14) and the other shutter (44, 144) at the exhaust of the cylinder (1). Motor according to claim 12, characterized in that the two rotary shutters are arranged so that the following operations: initially, when the piston of engine (4) is near its TDC, an air flow coming from of the compressor (14) passes through the lower shutter (42, 142) associated with the compressor, scans the additional volume (40, 140), crosses the upper shutter (44, 144) associated with the exhaust and escapes outwards via an exhaust manifold; in a second time, starting from about half of the trigger stroke of the piston motor, on the one hand, the upper shutter (44, 144) sets communicating the cylinder (1) with the additional volume for the fill with a mixture of air and burnt gases under pressure, and on the other hand, the cylinder communicates with the exhaust; in a third time, the upper shutter traps the mixture of air and burnt gases in the volume additional; fourth, the air coming from the compressor (14) is admitted into the cylinder, and into a fifth time, at the start of the compression stroke of the engine piston, the trapped and pressurized mixture is admitted into the cylinder. Motor according to claims 10 and 13 taken combination, characterized in that the upper shutter (44) is connected to the cylinder (1) by a pipe (45) arranged in the lower part of the cylinder and the lower shutter (42) is interposed on the pipe discharge (130) between the two stages (14a, 14b) of the compressor (14), so that the additional volume (40) is pressurized at means of the burnt gases from the cylinder (1) through the shutter upper (44) and is emptied into the cylinder by the pipe (45) connected to the upper shutter. Motor according to claim 13, characterized in that the upper shutter (144) is associated with at least one valve exhaust (118a) located at the top of the cylinder (1) and the shutter lower (142) is connected to the cylinder (1) by a pipe (141) arranged in the lower part of the cylinder, so that the additional volume (140) is pressurized by its upper end by means of the burnt gases from the exhaust valve (118a) through the upper shutter (144), and is emptied into the cylinder by its lower end through the lower shutter (142). Motor according to one of claims 1 to 14, characterized by the fact that it is of the loop scanning type (M1), in which the fuel mixture or fresh air is admitted from the compressor (14) by an intake manifold (16) opening through lights (17) in lower part of the cylinder (1) with an orientation such as mixing or the air is introduced with an upward rotation movement in a loop, while the gases burned from the previous cycle are evacuated by exhaust lights (18) also arranged in the lower part of the cylinder. Motor according to one of claims 1 to 13 and 15, characterized by the fact that it is of the uniflow type (M2), in which the fuel mixture or air is admitted at the bottom of the cylinder (1) to through intake lights distributed at the base of the cylinder and powered by a crown (117) itself connected to the compressor (14), while the gases burned from the previous cycle are discharged through one or more exhaust valves (118a) provided at the top of the cylinder. Two-stroke internal combustion engine according to one of the claims 1 to 13 and 15, or an internal combustion engine with four time according to one of claims 1 to 9, characterized in that it is of the type with exhaust and intake valves (M3, M4), in which the valves (118a, 217) are located at the top of the cylinder (1) and the intake valve (s) (217) are supplied by the compressor (14). Motor according to one of claims 1 to 18, characterized by the fact that it is of the type with several cylinders in line (M), in which the compressors (14) associated with each cylinder (1) are arranged alternately on each side of the cylinder block (2).

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