JP7214638B2 - valve ignition prechamber - Google Patents

Description

The subject of the present invention is a valve ignition prechamber making it possible to ignite a main charge introduced into a combustion chamber of an internal combustion engine by means of a spark ignited pilot charge, said prechamber being said main charge. designed to optimize the efficiency of the pilot charge to ignite the

The maximum and average efficiencies of state-of-the-art reciprocating internal combustion engines are relatively low. In automobiles, the maximum efficiency is about 35% for Otto cycle spark ignition engines and about 40% for Diesel cycle engines. Regarding the average efficiency in current use of automobile engines, it is in most cases less than 20 percent for spark ignition engines and less than 25 percent for diesel engines.

In such engines, part of the energy released by the combustion of fuel and not converted into useful work is dissipated, mainly in the form of heat in the cooling system and the exhaust of the engine.

In addition to low efficiency, reciprocating internal combustion engines used in automobiles produce polluting gases and particles that are harmful to the environment and health.

Despite these unfavorable characteristics, Otto cycle or diesel internal combustion engines are used in nearly every vehicle in the world because there are no other solutions that offer better energy, environmental, performance, and economic compromises. is deployed in

This situation explains the significant research and development efforts made by engine manufacturers to do whatever it takes to improve the energy and environmental balance of internal combustion engines. These efforts are aimed, inter alia, at perfecting the technologies that make up the engines and adding to them new capabilities that enable the execution of new strategies.

Among these strategies is the dilution of reciprocating internal combustion engine air and fuel charges with either neutral gases or oxygen-enriched fresh air.

The present invention relates to this dilution and is particularly directed to spark ignited reciprocating internal combustion engines that consume either gasoline or natural gas most of the time.

Diluting the charge of a spark ignition engine with fresh air or with pre-cooled exhaust gases makes it possible to increase the average and/or maximum thermodynamic efficiency of the engine. This reduces fuel consumption for the same useful work.

When a spark ignition engine operates at partial torque, introducing a diluted charge into its (their) cylinders results in less pumping losses than introducing an undiluted charge. Said loss reduction is due to the fact that the diluted charge material is larger for the same energy content. Therefore, for introducing the same amount of energy into the cylinder, the intake throttling of the engine, which is normally done by a throttle valve, is less pronounced and the gas pressure generated at the intake is higher. In addition, introducing the same energy into the cylinder of a spark ignition engine increases the mass and total heat capacity of the charge due to dilution of the charge. All other things being equal, therefore, the combustion of the charge takes place at a lower temperature. In addition to reducing the amount of nitrogen oxides produced by combustion, the low temperature reduces heat loss at the cylinder wall resulting from the transfer of some of its heat by the charge material to the wall. Let

Finally, the charge is less susceptible to uncontrolled auto-ignition of the air-fuel mixture, especially if the charge is diluted with oxygen-poor or oxygen-free neutral gases. Such autoignition causes rattling, an undesirable phenomenon characterized by explosive combustion that degrades the performance of spark ignited engines and damages the mechanical parts of which they are composed. The rattle desensitization provided by charge dilution may force the engine to operate at a higher compression ratio and/or with the most favorable time-triggered ignition possible from a performance standpoint. to enable.

In this particular context of dilution air and fuel loading, spark ignition engines operating with stoichiometric amounts differ from those above operating with excess air, also called "lean burn".

Stoichiometrically operating engines are only compatible with three-way catalysts, devices known per se for aftertreatment of pollutants resulting from combustion. The catalyst is responsible for burning the unburned hydrocarbons in the combustion chamber of the heat engine. The products of this combustion are water vapor and carbon dioxide already present in the atmosphere. The three-way catalyst also completes the oxidation of the notoriously polluting carbon monoxide, converting it to carbon dioxide, and reducing nitrogen oxides, making them about 78% of the earth's atmosphere. Converts to atmospheric dinitrogen, which is naturally non-polluting.

Reduction of nitrogen oxides by a three-way catalyst requires that the charge introduced into the engine is stoichiometric, i.e. it contains the correct amount of oxygen required for combustion of the hydrocarbons contained in said charge. need.

Excess oxygen makes it impossible for the three-way catalyst to reduce nitrogen oxides. It is therefore not possible to aftertreat the nitrogen oxides contained in the exhaust gases of engines operating with excess air using a three-way catalyst.

This means that engines running on excess air - to meet increasingly stringent environmental regulations - must have equipment specifically designed to reduce nitrogen oxides, such as nitrogen oxide traps or nitrogen oxides with urea. The reasons for accepting a device for selective catalytic reduction are explained. Such devices are generally placed at the outlet of a dual oxidation catalyst that has previously burned unburned hydrocarbons and completed oxidation of carbon monoxide and, increasingly, of a particulate filter.

Assuming that diesel engines naturally run with excess air, almost all European diesel vehicles have been equipped with aftertreatment devices to convert nitrogen oxides to dinitrogen since the Euro VI standard came into force in Europe. ing.

The problem with these devices is that they are expensive, complex, and their size and maintenance requirements make them almost exclusively used in diesel engines, where practically they can only operate with excess air. It is expensive.

As far as spark ignition engines are concerned, engine manufacturers make every effort to operate them stoichiometrically so that they remain compatible with three-way catalysts, which are simple and inexpensive for that matter.

To benefit from reduced fuel consumption caused by dilution of the charge in spark ignition engines without having to suffer the special economic disadvantages of nitrogen oxide traps or devices for selective catalytic reduction of nitrogen oxides with urea. Second, it is necessary to dilute the charge of the engine with oxygen-free neutral gas rather than oxygen-enriched air.

This latter gas is usually obtained by recycling the exhaust gases of the engine itself, which no longer contains oxygen and is available and abundant. This strategy is known under the name "Exhaust Gas Recirculation" or its acronym "EGR".

Since the gases exit hot at the exhaust of a spark ignited engine, their temperature must be reduced before mixing with fresh gases to prevent them from overheating the charge introduced into the engine. . This strategy is known as "cooled EGR" and specifies that the recirculated exhaust gas is cooled before being mixed with the fresh gas received by the engine. French engine manufacturers use the "Frenglish" term "EGR refroidi" which is easy to understand and use.

Pre-cooling of EGR gases is required for at least two purposes.

First, the temperature of the EGR gas/fresh gas mixture received by the spark ignition engine needs to remain low so that the volumetric efficiency of the engine remains high when operating at maximum torque. In fact, for a given intake pressure, the mass of the mixture introduced into the cylinder of the engine becomes all the more important that the mixture is cold. Pre-cooling of the EGR gases becomes even more important if the engine is supercharged by a turbocharger or any other means.

Second, hotter EGR gas/fresh gas mixtures cause rattling, which is detrimental to the performance of the engine.

The problem is that the cooled EGR diluted charge is low in oxygen. This is paradoxical as it is also a particularly sought-after goal for the charge material to remain stoichiometric and resistant to rattling. The result of this oxygen depletion is that combustion initialization is more difficult to achieve and develops slower than when the charge is not diluted with cooled EGR.

In a spark ignition engine combustion is initiated by creating a hot electric arc between two electrodes separated from each other by a few tenths of a millimeter.

When the air-fuel charge is highly diluted with cooled EGR, the electric arc passes through a mixture that is globally lean in oxygen and fuel. In fact, inhomogeneities inevitably arise in the three-dimensional space of the combustion chamber, with some pockets richer in oxygen and/or fuel than others, so that by chance there are dozens of gaps between the cathode and anode of the spark plug. The risk of misfire increases when the minute of space does not contain a sufficiently combustible EGR gas/fresh gas mixture.

Once combustion is initiated as expected, the fuel energy contained in the charge begins to be released as heat and the flame begins to develop. To accomplish this process, the flame transfers its heat in successive steps to the surrounding EGR gas/fresh gas mixture, ie from the combustible layer to the trailing combustible layer. Each layer releases heat as it is brought to its ignition temperature by the previous layer, combusts and it transfers to the next layer. According to the chain reaction principle, flame propagates in the three-dimensional space of the combustion chamber of a spark ignition engine.

The main problem with cooled EGR is that it makes combustion initiation difficult and due to the overall reduction in its temperature and the combustible and/or It is to considerably slow the development of the latter, due to varying degrees of abundance of fuel.

Moreover, it has been experimentally observed that the higher the content of charge material in the cooled EGR, the more unstable the engine. From a certain given content, misfires occur and efficiency (previously tended to increase with cooled EGR content of the charge) decreases. Above a certain content of EGR, the spark ignition engine shuts down and combustion cannot be initialized.

It is also observed that the unburned hydrocarbon and carbon monoxide content of the exhaust gas increases in parallel with the cooled EGR content of the charge. This is due to the fact that the pockets of mixture are too poor to be properly faced and burned by the flame on their path and that the boundary layer flame plugging near the cold inner walls of the engine combustion chamber thickens. Both are the cause.

Furthermore, experimentally, it is also observed that the higher the ignition power, the higher the cooled EGR content of the charge material is possible without significantly altering the stability of the engine.

Thus, many laboratories, such as the Southwest Laboratories in the United States, have developed increasingly powerful electric ignition devices to push down the accessible limits of cooled EGR content of charge materials. The objective of this strategy is, of course, to improve the efficiency of spark ignition engines.

The problem with increasing the power of electric ignitions is that their performance degrades rapidly with their power. Therefore, more power is required to obtain less and less additional ignition power.

In addition, high power is important if the spark plug electrodes are spaced apart from each other so that the spark is more likely to cross combustible pockets, or if the duration of the spark is increased, or if the spark is repeated. This results in higher and higher voltages and powers, which make the implementation of spark plug electrical insulation more complex, while dramatically shortening spark plug life.

The difficulty in igniting the charge material is due to the fact that cooled EGR is more of a concern in turbocharged spark ignited engines where the goal is essentially to reduce sensitivity to rattle. But also. However, the higher the boost pressure, the denser the EGR gas/fresh gas mixture between the electrodes of the spark plug at the moment of spark activation, and the more voltage required to provoke the spark. On that basis, cooled EGR, with the same energy introduced into the engine's cylinders, does not go in the right direction because the mass of the gas between the electrodes increases with the resistance of said gas to ignition.

Patent FR 2 986 564 belonging to the applicant is noted to be a strong response to these problems. The spark ignition and high pressure stacking devices for internal combustion engines referred to in the above patents are highly flammable and not diluted with cooled EGR at the center of the spark plug and just before the spark is triggered. and proposes injecting a potentially slightly fuel-rich, near-stoichiometric pilot charge under high pressure.

After being injected by the device, the charge material pilot immerses the spark plug electrodes as soon as an electric arc is formed between the electrodes, and the charge material immediately ignites and releases the energy it contains. Thus, the charge material itself is the means to ignite itself, and its power is hundreds to thousands of times greater than that of the electric arc that allowed it to ignite. It is practically impossible to obtain such ignition power by electrical means alone.

In fact, experience has shown that cooled EGR rates of about 50 percent are possible with such devices, compared with only about 30 percent for simply the most powerful electric ignition devices.

The approach taken in patent FR 2 986 564 was proposed by inventor Fred N. Sauer andJ. No. 4,319,552 to Brian Barry or DE 41 40 962 A1 belonging to the Bosch Company in related form.

In any event, Orbital Company's U.S. Pat. No. 6,564,770 states that the purpose of this patent is to ensure a composition of the main charge that is as uniform as possible at relatively low pressures and that the main charge is highly diluted with EGR. It does not fall into this category as it does not form a pilot charge for ignition purposes.

The problem with the devices described in patent FR 2 986 564 and the devices described in the related patents they just mentioned lies in the development of said combustion rather than the very efficient initiation of combustion. . In particular, when the burn fraction of the fuel contained in the main charge reaches about 50%, the combustion struggles to progress, thereby reducing the total time required to burn all of the main charge. longer than the time required to burn all of the EGR-diluted charge.

As a result, some of the potential energy gain of cooled EGR is lost due to very slowly developing combustion.

However, a spark ignition engine is found in the same engine on the one hand with a main charge having a cooled EGR content of the order of 50% and on the other hand when the same engine burns an undiluted charge. The greatest benefit of cooled EGR would be found if it were possible to simultaneously operate with stability and total combustion duration comparable to that of the EGR engine.

The solution can come from the use of a pre-chamber into which the pilot charge material can be introduced, said pre-chamber being able to house the electrodes of the spark plug; can be formed as an integral part of the spark plug as proposed in .

The first advantage of such a prechamber is that it potentially keeps the pilot charge as close as possible to the electrodes of the spark plug, which is the main fuel of the spark ignition engine prior to ignition of said charge. Dispersion of the charge material in the combustion chamber can be limited.

A second advantage of the prechamber is that once ignited, the pilot charge pressurizes the prechamber and the prechamber passes through holes contained in the prechamber at high speed to the main combustion chamber of the spark ignition engine. to send the torch.

Ignition of the main charge with this torch is very efficient. This is because the flame is initiated at multiple locations in the combustion chamber, moving from the perimeter of the combustion chamber to the center of the combustion chamber, rather than starting from the center of the combustion chamber as is the case with normal spark plug ignition. and tangentially between each torch.

The energy of the fuel is therefore released in a very short time, which is favorable for the thermodynamic efficiency of spark ignition engines. Not only is the trigger more productive in terms of useful work, but the slightest sensitivity to rattle resulting from such rapid combustion makes the engine run at a significantly higher volumetric ratio. because it makes it possible

In any case, the solution proposed in US Pat. It does not compare to the numerous patents that concern fuel injected into the chamber alone or not, and not a mixture of air and fuel.

Among these patents, for example, GB 2 311 327 A from <Fluid Research Limited>, US Patent No. 4,864,989 from <Tice Technology Corp>, US U.S. Pat. No. 4,124,000, U.S. Pat. No. 4,239,023 from <Ford Motor Company>, inventor U.S. Pat. No. 4,892,070 from Dieter Kuhnert, inventor Reference is made to what is known under US Patent Application Publication No. 2001/0050069 A1 from Radu Oprea and Edward Rakosi, or US Patent Application Publication No. 2012/0103302 A1 from inventor William Attard, and the principles thereof. based on, an ignition system called "Turbulent Jet Ignition" was developed by the German company Mahle for Formula 1 engines.

In fact, with respect to "lean-burn" spark-ignited engines, the sole purpose of which is to enrich the fuel load around the ignition point on glands where the charge material is overall fuel-lean but oxygen-rich. and a spark-ignited engine operating with a highly diluted charge with cooled EGR, and around the ignition point, the charge is generally depleted of fuel and oxygen. There is a fundamental difference between the solutions described in FR 2 986 564 and related patents, which aim to build a fuel-oxygen rich mixture on less ground.

At this stage, as proposed in patent FR 2 986 564, EGR is achieved by injecting a highly combustible pilot charge consisting of air and fuel and enveloping the spark plug electrodes with said charge. It can be seen that it makes it possible to effectively ignite a strongly diluted main charge.

It has also been found that once the main charge is ignited, combustion proceeds rapidly until about 50 percent of the total fuel contained in the charge is burned. Above the 50%, combustion develops more slowly, so from a given EGR content of the main charge, the thermodynamic efficiency of the spark ignition engine decreases instead of increasing as expected.

The latter problem of combustion development in excess of 50% occurs when pilot charge material is injected into the prechamber containing the electrodes of the spark plug, as proposed in U.S. Pat. No. 4,319,552. assumed to be wholly or partially resolved.

Indeed, the prechamber emits a torch of hot gas energized at high velocity through its holes, which not only initiates combustion over a large radial length around the ignition point, but also of the flame perpendicular to the torch. It will crease the flame front which will facilitate development.

However, this last solution may prove unsatisfactory for a number of reasons, some of which have led to the abandonment of prechamber-based ignition systems, particularly in the context of spark ignition engines.

In fact, to be effective, the prechamber must have a protruding dome that penetrates well into the combustion chamber of the engine so that the air exposed by and through said dome is exposed. The holes through which the hot gases are emitted to form the torch are positioned well inside the combustion chamber so that the torch does not lick the cold inner walls of the engine.

However, as soon as combustion is initiated in the prechamber, the gas contained within the prechamber rises in pressure rapidly and is discharged at high velocity through the holes. In doing so, the gas heats the dome.

When combustion of the main charge is initiated, the pressure in the combustion chamber of the engine rapidly exceeds that in the prechamber, causing hot gases to pass in the opposite direction through the holes in the dome, reheating the dome.

During expansion of the gases by the piston of a spark ignition engine, the pressure in the prechamber becomes greater than the pressure in the combustion chamber of the engine. As a result, the hot gas contained within the prechamber passes through the holes three times and further heats the dome.

However, from a certain temperature, the protruding dome becomes like a "hot ball" in the internal combustion engine ignition system invented by Stuart Herbert-Akroyd and described in patent CHD4226 of Dec. 4, 1891. behave. Such hot spots can lead to inadvertent, non-spark controlled ignition of the main charge material. The rattling that may follow can damage or even destroy the spark ignition engine.

A solution may be to significantly cool the dome to prevent it from becoming a hotspot. However, the resulting heat release sacrifices, on the one hand, the efficiency of the hot gas torch, whose temperature and velocity drop during passage through the dome holes, and, on the other hand, the thermodynamic efficiency of the spark ignition engine. occur at the expense of

Therefore, the inability of the prechamber to behave like a "hot ball" igniter as described above, or at least the initiation of combustion of the main charge material to be reliably triggered at selected times and occurring at uncontrolled times. It is essential that there is no

This involves cooling a hot portion of the prechamber that can trigger auto-ignition, which spreads the hot gas torch into the three-dimensional space of the engine's combustion chamber containing the main charge material. without significantly impairing the effectiveness of

Also note that the configuration of the pressurized air-fuel pilot charge is not energetically free. It is necessary to first compress the air (this requires a compressor driven by the spark ignition engine itself) and then inject fuel into the air. Another strategy could be to directly compress the previously composed air-fuel mixture.

Therefore, for the same ignition efficiency, the smaller the mass and pressure of the pilot charge compared to that of the main charge, the lesser the mass and pressure of the spark ignition engine when operating under higher EGR rates, due to non-negligible energy costs. The final energy balance will be better. It is therefore necessary to give the pilot charge the highest possible specific efficiency for the mass and pressure of the pilot charge by all possible means in order to ignite the charge.

In other words, for the same ignition efficiency, the pilot charge should contain as little air-fuel mixture as possible, previously placed under the lowest possible pressure.

Therefore, it is necessary to avoid as far as possible the pilot charge from dispersing into the main charge prior to its ignition. This is because such dispersion reduces the specific efficiency of the pilot charge to ignite the main charge and increases the mass of said pilot charge (which does so at the expense of fuel efficiency in spark ignited engines). because it can only be offset by

Dispersion is due, inter alia, to the time required by the injector to introduce the pilot charge into the prechamber to effect injection of said pilot charge under a pressure necessarily greater than that of the main charge.

The injection pressure of the pilot charge remains nearly constant, while the pressure of the main charge increases under the influence of compression of the spark ignition engine's piston after it rises towards its top dead center. Please note. The initiation of injection of the pilot charge is therefore performed under a greater differential pressure than the termination of said injection. As a result, the rate of discharge of the constituent gases of the pilot charge by the injector is greater at the beginning of injection than at the end of injection.

Prior to injecting the pilot charge, the pressure in the prechamber is lower than the pressure in the compression chamber of the engine. Accordingly, a portion of the main charge material first enters the prechamber as the charge material is being compressed.

The injector then injects a pilot charge into the prechamber where it has a high EGR content and mixes with a portion of the main charge previously introduced into the prechamber.

The excess gas mass resulting from the above portion is then exhausted from the prechamber along with a portion of the pilot charge, which mixes with the high EGR content gas in and out of the prechamber.

Therefore, the combustibility of the mixture of air, fuel and EGR is necessarily non-uniform within and outside the volume of the prechamber. The effectiveness of igniting the pilot charge as early as possible is thus reduced, as is the efficiency of the hot gas torch for igniting the main charge.

This decrease in efficiency can only be offset by increased air and fuel mass in the pilot charge, at the expense of the overall energy efficiency of the spark ignition engine.

Ideally, therefore, dispersal of the pilot charge into the main charge prior to ignition of the pilot charge should be avoided by any possible means.

This does not at all matter the fact that it would be very advantageous to improve the device described in patent FR 2 986 564. In fact, the device has been effective in initiating combustion at very high levels of cooled EGR and in developing said combustion until about 50% of the fuel contained in the main charge has been burned. .

The purpose would be to give the device the ability to develop the combustion very quickly until at least 90% or 100% of the fuel has been burned.

As mentioned earlier, this is not possible with prechambers such as those suggested in U.S. Pat. It can be achieved provided that it is possible to avoid it. To this end, avoid it behaving like a "hot ball", prevent the pilot charge material from dispersing into the main chamber, and There is a need to significantly improve the effectiveness of the prechamber, including limiting the amount of energy required while maintaining the same ignition efficiency.

All of these objectives are addressed by a valve ignition prechamber according to the invention, which - according to a particular embodiment - allows:
• Significantly reduce the heat load experienced by the protruding dome exposed by the prechamber. This is accomplished by dividing by about 3 the number of passes of hot gas through the holes in the dome through which the gas exits, thereby exposing the dome to excessive temperatures and the main charge material. are protected from becoming hot spots that can cause inadvertent self-ignition.
minimizing the mass and pressure of the pilot charge required not only for initializing the combustion of the EGR heavily diluted main charge, but also for the rapid development of said combustion until all of said main charge is burned; to do.
- To achieve this last objective, avoid dispersion of the pilot charge in the main charge during its injection into the prechamber.

To achieve all of these objectives, the valve ignition prechamber according to the invention allows:
when the pressure therein is lower than the pressure in the combustion chamber, in order to avoid undesirable back and forth excursions of hot gases through the holes in the protruding dome through which the prechamber communicates with the combustion chamber; , keep the antechamber closed.
- keep the prechamber closed for the majority of the pilot charge injection time so that the injection takes place in a closed space in which the pilot charge gases cannot mix with the main charge gases; to do.
• Reducing pilot charge mass and injection pressure while maintaining high pressure and ejection velocity of hot gas through protruding dome holes.

The valve ignition prechamber is designed to be inexpensive to mass produce so as to remain compatible with the economic constraints of most applications for which it is intended, including automotive.

The valve ignition prechamber according to the invention, of whatever type, whatever kind of fuel, gas, liquid or solid it consumes, and whatever its main charge is by cooled EGR, It is understood to be applicable to any spark ignited rotary or linear internal combustion engine diluted or not by any natural neutral gas or by oxygen-rich gas or by any other combustion agent.

It is also understood that the pilot charge received by the valve ignition prechamber according to the present invention may include fuel and/or a combustible agent different from fuel and/or a combustible agent that constitutes the main charge of a spark ignition engine.

Other features of the invention are set forth in the present description and in the secondary claims depending directly or indirectly from the main claim.

An ignition prechamber valve according to the invention is provided for an internal combustion engine with a cylinder head capping the cylinder to form a combustion chamber in which a main charge can be burned, said prechamber comprising:
- at least one stratified cavity, located in the cylinder head on the one hand and connected to the combustion chamber by a laminated duct, and on the other directly or indirectly carrying a pilot charge previously pressurized by compression means; at least one stratified cavity receiving a stratified injector capable of injecting into said cavity, said charge material comprising a combustible/AF fuel mixture readily combustible by a spark;
an ignition means that opens into the stack cavity and is capable of igniting the pilot charge;
the lamination duct can be closed in whole or in part, exposing on the one hand the cavity-side face exposed to the pressure of the gases in the lamination cavity and on the other hand the chamber-side face exposed to the pressure of the gases in the combustion chamber; towards the laminated cavity if the pressure in the laminated cavity is lower than the pressure in the combustion chamber, or towards the combustion chamber if the pressure in the combustion chamber is lower than the pressure in the laminated cavity. a laminated valve capable of translating relative to said duct under the influence of gas pressure towards
- at least one cavity-side valve stop that determines the position of the stack valve closest to the stack cavity;
• at least one chamber-side valve stop that determines the position of the stacked valve closest to the combustion chamber;

The valve ignition prechamber according to the present invention closes all or part of the laminate duct when it is closest to the laminate cavity, while opening the duct over a wider portion when it is positioned closest to the combustion chamber. Equipped with a laminated valve that

A valve ignition prechamber according to the present invention comprises a cavity-side valve stopper consisting of a valve closing seat positioned within or at either end of the laminated duct, said seats surrounding and/or at the ends of the laminated valve. cooperating with a cavity-side valve support surface located on the part.

A valve ignition prechamber according to the invention comprises a valve closing seat and a cavity side valve seat which form a seal when in contact with each other, said seal being closed when the pressure in the combustion chamber is higher than the pressure in the stacked cavity. prevent any gas from passing through the contact.

A valve ignition prechamber according to the present invention comprises a chamber-side valve stop consisting of a valve opening seat located in or at either end of the laminated duct, said seats surrounding and/or at the ends of the laminated valve. It cooperates with a chamber-side valve support surface located on the part.

A valve ignition prechamber according to the present invention includes a valve opening seat and a chamber-side valve seat that form a seal when in contact with each other, thereby preventing any gas from passing through the contacts.

The valve ignition prechamber according to the present invention comprises a laminated valve, which positions said valve substantially centrally within the laminated duct, whatever the axial position of said valve with respect to said duct, and said Guiding means are provided around its perimeter to maintain approximately the same longitudinal orientation as the duct.

The valve ignition prechamber according to the invention is such that when the valve opening seat and the chamber-side valve support surface are in contact with each other, the laminated valve, together with the laminated duct, forms a laminated cavity on the one hand and at least one gas discharge hole on the other hand. forming a torch ignition prechamber simultaneously communicating with the combustion chamber via .

The valve ignition prechamber according to the invention comprises the inner peripheral wall of a cylindrical torch ignition prechamber, while the stacked valve has a circular outer periphery and is received within said prechamber with low radial clearance.

The valve ignition prechamber according to the invention comprises a laminated duct which houses the torch ignition prechamber and which projects and opens into the combustion chamber in the form of a protruding discharge dome from which the gas discharge holes open.

A valve ignition prechamber according to the present invention comprises a valve release seat located within a protruding discharge dome.

The valve ignition prechamber according to the present invention is such that when the stacked valve is placed near the combustion chamber, i.e., when placed in close proximity to or in contact with the chamber-side valve stopper with which it cooperates, said valve: Providing for exposing at least one gas discharge hole connecting the laminate cavity with the combustion chamber.

The valve ignition prechamber according to the invention comprises ignition means consisting of an ignition spark plug closing a first end of a perforated connecting tube, the perforated connecting tube passing through all or part of the internal volume of the laminated cavity. and its body is radially traversed by at least one radial slot connecting the interior of said tube to said interior volume, while a second end of said tube receives a laminate duct and a laminate valve; On the one hand, the center electrode of the spark plug and the ground electrode are accommodated in the perforated connecting tube.

A valve ignition prechamber according to the present invention has a cavity-side surface that exposes the aerodynamic dome.

A valve ignition prechamber according to the invention comprises a cavity-side surface forming a ground electrode facing a center electrode contained in an ignition spark plug, the ignition spark plug constituting the ignition means.

A valve ignition prechamber according to the present invention comprises a laminated valve that is axially thicker at its periphery than at its center, which receives a cavity-side valve support surface and a chamber-side valve support surface.

The description that follows, with reference to the accompanying drawings, given as non-limiting examples, will serve for a better understanding of the invention, its features and the advantages it may offer.

1 is a schematic cross-sectional view of a valve ignition prechamber according to the invention, such as can be installed in a cylinder head of an internal combustion engine; FIG. Figure 2 is a schematic cross-sectional view of a valve ignition prechamber according to the present invention, wherein the laminated valve completely closes the laminated duct when the cavity-side valve support surface included in said laminated valve contacts the valve closing seat with which it cooperates; Alternatively, the stacked valve forms a torch ignition prechamber housed in a protruding discharge dome when the valve rests on the chamber-side valve stop. 3A-3D are partial enlarged schematic cross-sectional views of a valve ignition prechamber according to the present invention and according to the particular configuration shown in FIG. 2, said enlarged views showing various stages of operation of said prechamber; Figure 3 is a schematic cross-sectional view of a valve ignition prechamber according to the invention incorporating the main features shown in Figure 2 with the addition of a radially drilled connecting tube traversed by radial slots, said tube being a laminated cavity; It passes through the internal volume and is integrated with the ignition spark plug, while the cavity side face of the laminated valve forms a ground electrode facing the center electrode contained in said spark plug. 10 is a three-dimensional view of a valve ignition prechamber in accordance with the present invention and in accordance with the embodiment shown in FIG. 9; FIG. 10 is a three-dimensional view of a broken longitudinal section of a valve ignition prechamber according to the invention and according to the variant embodiment shown in FIG. 9; FIG. 10 is an exploded three-dimensional view of a valve ignition prechamber in accordance with the present invention and in accordance with an alternative embodiment shown in FIG. 9; FIG.

1 to 12 show various details of the valve ignition prechamber 1, its components, its variants and its accessories.

From FIG. 1 it can be seen that the valve ignition prechamber 1 is specially designed for the internal combustion engine 2 . The internal combustion engine 2 comprises a cylinder head 3 which caps a cylinder 4 to form with a piston 31 a combustion chamber 5 in which a main charge 30 can be combusted.

1 to 12, the valve ignition prechamber 1 according to the invention comprises at least one laminated cavity 6, which is arranged on the one hand in the cylinder head 3 and connected to the combustion chamber 5 by means of a laminated duct 7, On the other hand, it is noted that it receives a layered injector 8 which can directly or indirectly inject a pilot charge 9 pre-compressed by compression means 10 into said cavity 6 .

According to the invention, the pilot charge material 9 consists of a combustible-AF fuel mixture readily combustible by a spark.

1, 2 and 9 show that a laminate injector 8 is included in the valve ignition prechamber 1 according to the invention and directly or indirectly injects a pilot charge 9 into the laminate cavity 6 via an injector outlet duct 28. shows what you can do.

The stacked injectors 8 can be of any type without limitation and the combustible-AF fuel mixture contained in the charge 9 can be injected with the possible assistance of another injector, either gas or liquid, or known per se. It may consist of any device capable of introducing a pilot charge 9 into the lamination cavity 6 by any operating procedure, whether formed upstream or downstream of said lamination injector 8 with the aid of a vaporizer. can.

Furthermore, the lamination cavities 6 and the lamination ducts 7 can advantageously be coated with a refractory material known per se or made from said materials. Alternatively, an air gap is left between at least part of the lamination cavity 6 and/or lamination duct 7 and the cylinder head 3 receiving these components 6,7, whereby said components 6,7 and said cylinder head 3 You may make it limit the heat exchange between.

1 to 12, the valve ignition prechamber 1 according to the invention comprises ignition means 11 opening into the stacking cavity 6 and capable of igniting the pilot charge 9, said means 11 optionally itself It can be seen that it consists of a known ignition spark plug 12 .

1 to 12, the valve ignition prechamber 1 according to the invention is a laminated valve 13 capable of closing all or part of the laminated duct 7 while the gas present in the laminated cavity 6 is blocked. It is noted that it includes a laminated valve 13 that exposes a cavity-side surface 14 exposed to pressure and a chamber-side surface 15 that, on the other hand, is exposed to the pressure of gases present in combustion chamber 11 .

The laminated valve 13 is directed towards the laminated cavity 6 when the pressure in the laminated cavity 6 is lower than the pressure existing in the combustion chamber 5 or the pressure existing in the combustion chamber 5 exists in the laminated cavity 6. Note that it is possible to translate with respect to the laminated duct 7 under the influence of the pressure of the gas towards said combustion chamber 5 when it is lower than the pressure.

Note that the laminated valve 13 can also move within the laminated duct 7 under the influence of gravity or acceleration, but this is neither seen as an advantage nor as a desired mode of operation.

It can be emphasized that the laminated valve 13 can be made from a heat resistant superalloy and kept as light as possible, or it can be made from a ceramic material such as silicon carbide.

In addition to what has just been said, it is noted that the valve ignition prechamber 1 according to the invention includes at least one cavity-side valve stop 16 that determines the position of the stack valve 13 closest to the stack cavity 6 . This is particularly evident in FIGS. 3-8.

Furthermore, the valve ignition prechamber 1 according to the invention comprises at least one chamber-side valve stop 17 that determines the position of the stack valve 13 closest to the combustion chamber 5 .

As a variant of the valve ignition prechamber 1 according to the invention, the laminated valve 13 can close all or part of the laminated duct 7 when it is closest to the laminated cavity 6 while it is in the combustion chamber 5. It is noted that the duct 7 is open over a wider portion when located closest.

3 to 8, the cavity-side valve stop 16 may consist of a valve closing seat 18 provided in or at either end of the laminated duct 7, said seat 18 being located in the laminated valve 13. It is noted that it cooperates with cavity-side valve support surfaces 19 located around and/or at the ends of the .

Also, the valve closing seat 18 and the cavity-side valve support surface 19 can form a seal when they are in contact with each other, said seal allowing the pressure in the combustion chamber 5 to Note that it prevents any gas from passing through the contact when higher than .

As another variant, the chamber-side valve stop 17 may consist of a valve opening seat 20 provided in or at either end of the laminated duct 7 , said seat 32 surrounding the laminated valve 13 . and/or with the chamber-side valve support surface 21 arranged at the end.

In this case, the valve opening seat 20 and the chamber-side valve support surface 21 can form a seal when they are in contact with each other, thereby preventing any gas from passing through said contact.

As is evident from FIGS. 3 to 8 and 12, the laminated valve 13 may be provided with guide means 22 around its circumference, which hold said valve 13 approximately in the center of the laminated duct 7 and , maintains approximately the same longitudinal orientation of the duct 7 regardless of the axial position of the valve 13 relative to the duct 7 .

2, 3, 6, 8 and 9, the laminated valve 13 can form a torch ignition prechamber 23 with the laminated duct 7 when the valve opening seat 20 and the chamber side valve support surface 21 are in contact. , the torch ignition prechamber 23 simultaneously communicates with the stack cavity 6 on the one hand and the combustion chamber 5 via at least one gas discharge hole 24 on the other hand.

In this particular context of the ignition prechamber valve 1 according to the invention, the inner peripheral wall of the torch ignition prechamber 23 may be cylindrical, whereas the laminated valve 13 has a circular perimeter and the inner peripheral wall of said prechamber 23 has a circular perimeter. , so that regardless of the position of the valve 13 relative to the prechamber 23, a small radial gap remains between the valve 13 and the wall, and the small gap is It forms a restricted passage that slows the passage of gas between the cavity 6 and the combustion chamber 5 .

1 to 12 show, according to a particular embodiment of the valve ignition prechamber 1 according to the invention, the laminated duct 7 houses a torch ignition prechamber 23 and a protruding discharge dome 25 from which the gas discharge holes 24 open. can be opened and protruded into the combustion chamber 5 in the form of

It is noted that the gas discharge holes 24 can be directed more or less towards the combustion chamber 5 and exit more or less tangentially at the periphery of the projecting discharge dome 25 . Additionally, the shape of the gas discharge holes 24 may vary depending on whether the jet of gas exiting said holes 24 is designed to be directional or diffusive. By way of example, gas discharge holes 24 may be cylindrical, conical, or form a convergence or divergence.

Advantageously, and as shown in FIGS. 1-12, the valve opening seat 20 can be arranged in a protruding discharge dome 25, which is made of an anti-friction and/or non-stick material and/or known per se. Or it can be coated with a refractory material or made from the above materials.

In general, when the stacked valve 13 is placed near the combustion chamber 5, i.e. near or in contact with its cooperating chamber-side valve stop 17, said valve 13 will be exposed to the stacked cavity. It is understood that at least one gas discharge hole 24 connecting 6 to combustion chamber 5 may be exposed.

9-12, the ignition means 11 may consist of a spark plug 12 closing a first end of a perforated connecting tube 26, the perforated connecting tube 26 being the inner volume of the laminate cavity 6. and its body is radially traversed by at least one radial slot 27 connecting the interior of said tube 26 to said interior volume, the second end of said tube 26 being The center electrode 40 and the ground electrode 39 of the spark plug 12 are accommodated in the perforated connecting tube 26, receiving the laminated duct 7 and the laminated valve 13. As shown in FIG.

9-12, it should be noted that the perforated connecting tube 26 may be part of the spark plug 12 from which it extends its seating surface. In this case, the spark plug 12 is screwed directly into the cylinder head 3 by a thread formed on the outer cylindrical surface of its seat and/or on the outer cylindrical surface of the perforated connecting tube 26 extending from it.

Alternatively, the spark plug 12 may be threaded into the tube 26 while the tube 26 is threaded into the cylinder head 3 . In any case, a seal is formed between the cylinder head 3 on the one hand and the spark plug 12 and/or the perforated connecting tube 26 on the other hand, both at the spark plug 12 and the laminate duct 7 .

9-12 show that the cavity-side surface 14 can expose the aerodynamic dome 29, in particular by providing the least possible resistance to the flow of gas and Generating as little turbulence as possible in the flow makes it possible to direct the gas discharge holes 24 .

1 to 12 illustrate that, according to a particular embodiment of the valve ignition prechamber 1 according to the invention, the cavity-side surface 14 forms a ground electrode 39 facing a center electrode 40 contained within the spark plug 12. The spark plug 12 constitutes the ignition means 11 and an electric arc is formed between the ground electrode 39 and the central electrode 40 when a high voltage current flows from the central electrode 40 to the ground electrode 39. shows that it is possible.

1-12 further illustrate that the laminated valve 13 may be axially thicker at its periphery, which receives the cavity-side valve support surface 19 and the chamber-side valve support surface 21, than at its center.

This feature gives the valve 13 a radial thickness that gradually increases from the center of the valve 13 towards its periphery, whereby the valve 13 comprises valve support surfaces 19, 21 and a valve It is the lightest possible and most resistant to shocks possible while ensuring that the support surfaces 19,21 cool most effectively at the contact between the cooperating sheets 18,20.

Modes of Operation of the Present Invention The modes of operation of the valve ignition prechamber 1 according to the present invention are readily understood with reference to FIGS.

According to a non-limiting example of application of the valve ignition prechamber 1 according to the invention shown in FIG. It can be seen that it is implemented in an internal combustion engine 2 with a cylinder head 3 capping a cylinder 4 .

The piston 31 is connected to the crankshaft 37 via a connecting rod 38, and when the piston 31 is driven by alternating translational movements within the cylinder 4, the piston 31 imparts rotary motion to the crankshaft 37. Please pay attention to

FIG. 1 also shows that the combustion chamber 5 can be arranged to communicate with the intake duct 32 via the intake valve 34 while said combustion chamber 5 can be arranged to communicate with the exhaust duct 33 by means of the exhaust valve 35 . show.

1 to 8 are taken here by way of example to explain the mode of operation of the valve ignition prechamber 1 according to the invention, showing that said prechamber 1 is integrated with the cylinder head 3 . 1 to 8 also show that the ignition means 11 here consist of a spark plug 12 known per se, the electrodes of which open into the laminate cavity 6 . A laminate injector 8 capable of injecting a pilot charge 9 into the laminate cavity 6 via an injector outlet duct 28 can be seen in FIGS.

In FIG. 1 it is noted that prior to injection by the laminated injector 8, the pilot charge 9 consisting of a combustible combustible-AF fuel mixture is pressurized by the laminated compressor 36 forming the compression means 10. be done. This is also a non-limiting example of embodiment of the valve ignition prechamber 1 according to the invention and is taken here as an example to explain the mode of operation.

In order to explain the mode of operation of the valve ignition prechamber 1 according to the invention, it is assumed here that the volumetric ratio of the internal combustion engine 2 is 14:1, excluding the valve ignition prechamber 1 . To obtain this result, when a volume of 500 cubic centimeters is displaced by piston 31, the volume of combustion chamber 5 is 38.5 cubic centimeters.

Further, and as a non-limiting example, the volume of the ignition valve prechamber 1, including the volume of the laminate duct 7 and the volume of the injector outlet duct 28, is here 0.5 cubic centimeters.

The exemplary embodiments shown in FIGS. 1-8 will now be used to describe in detail the mode of operation of the valve ignition prechamber 1 according to the invention, wherein the cavity-side valve stopper 16 is located in the laminated duct 7. It is found to consist of a valve closing seat 18 arranged, said seat 18 cooperating with a cavity side valve support surface 19 arranged around the stack valve 13 .

Here, the valve closing seat 18 and the cavity-side valve support surface 19 are selected to form a seal when in contact with each other, the seal being such that the pressure in the combustion chamber 5 is higher than the pressure in the stack cavity 6. Occasionally prevent any gas from passing through the contact.

To explain the mode of operation of the valve ignition prechamber 1 according to the invention, it is also provided that the chamber-side valve stopper 17 consists of a valve opening seat 20 arranged in the laminated duct 7, said seat 32 being the laminated valve It is also noted to cooperate with a chamber-side valve support surface 21 located around 13 . This particular configuration is clearly visible in FIGS. 3-8.

In this particular situation, it is provided to provide a seal when the valve opening seat 20 and the chamber side valve support surface 21 contact each other to prevent the passage of any gas at said contact.

2, 3, 6 and 8, when the valve opening seat 20 and the chamber-side valve support surface 21 are in contact with each other, the laminated valve 13 together with the laminated duct 7 extend into the annular torch ignition prechamber 23. , and that said pre-chamber 23 is in simultaneous communication with the stacking cavity 6 on the one hand and the combustion chamber 5 on the other hand via several gas discharge holes 24 .

The inner peripheral wall of the torch ignition prechamber 23 is cylindrical, while the stack valve 13 has a circular peripheral edge and is housed in the prechamber 23 with a small radial clearance so that the above Regardless of the position of valve 13, a small radial gap remains between said valve 13 and said wall, said small gap permitting the passage of gas between laminated cavity 6 and combustion chamber 5 through said small gap. Note also that it forms a restricted passageway that slows down .

1 to 8, the laminated duct 7 projects and opens into the combustion chamber 5 in the form of a projecting discharge dome 25, which accommodates the torch ignition chamber 23 and, according to this example, the combustion chamber 5. It is also noted to open therefrom a gas discharge hole 24 directed toward the . It is incidentally noted that the valve opening seat 20 is located within the protruding discharge dome 25 .

1-8, the cavity-side face 14 of the laminated valve 13 exposes an aerodynamic dome 29 which, among other things, provides the lowest possible resistance to the flow and allows the flow to enter the flow. It can be seen that it makes it possible to direct the gas flow towards the gas discharge holes 24 by creating the lowest possible turbulence.

It is also noted that the laminated valve 13 is axially thicker at its periphery than at its center. This feature ensures the most effective cooling possible at the contact between the valve support surfaces 19, 21 and the seats 18, 20 with which the valve support surfaces 19, 21 cooperate, while ensuring that the valve Allowing 13 to be the lightest possible and as resistant to impact as possible. As a non-limiting example, stack valve 13 can be made of superalloys that are mechanically and thermally highly resistant.

For the embodiment of the valve ignition prechamber 1 according to the invention shown in FIGS. , the maximum travel that the stack valve 13 can move between the valve closing seat 18 and the valve opening seat 20 is considered to be equal to 15/100 millimeters.

In order to understand the mode of operation of the valve ignition prechamber 1 according to the invention, it is now useful to divide its operation into four stages of the internal combustion engine 2 with reference to FIGS.

Consider that the internal combustion engine 2 operates on a near stoichiometric air-gasoline main charge 30 heavily diluted with cooled recirculated exhaust gas known as "cooled EGR". The charge material 30 is therefore resistant to ignition and in no way facilitates its rapid development of combustion within the three-dimensional space of the combustion chamber 5 .

The pilot charge 9 implemented by the valve ignition prechamber 1 according to the invention is therefore not only capable of initializing the combustion of the main charge 30, but also of developing said combustion in the shortest possible time. It is expected to have the maximum efficiency possible. It will be appreciated that these two objectives are directly achieved by the valve ignition prechamber 1 according to the invention.

According to the non-limiting embodiment of the valve ignition prechamber 1 according to the invention, which will now be taken to describe its mode of operation, the pilot charge 9 is one comma 6 of the fuel contained in the main charge 30 %, the pilot charge material 9 consists of a highly combustible combustible-AF fuel mixture with a spark.

Here, the four-stroke cycle designed/conceived by Otto/Baud de Rochas is decomposed in the usual order.

In the intake phase, the piston 31 of the internal combustion engine 2 descends into the cylinder 4 with which it cooperates, whereby the main charge 30 coming from the intake duct 32 through the intake valve 34 which is kept open. introduced into the cylinder 4;

During the above stages the pressure in the combustion chamber 5 is lower than the pressure in the stacking cavity 6 . As a result, and as shown in FIG. 3, the stack valve 13 remains pressed against the valve opening seat 20 with which it cooperates and the stack cavity 6 is opened by the gas discharge holes 24 through the torch ignition prechamber 23. It is placed in communication with the combustion chamber 5 .

When the piston 31 reaches its bottom dead center, the inlet valve 34 closes and the piston 31 begins to rise within the cylinder 4 to its top dead center.

The piston 31 then compresses the main charge 30 and the pressure in the combustion chamber 5 is higher than the pressure in the stacking cavity 6 .

The pressure difference between the combustion chamber 5 and the cavity 6 is reduced, on the one hand, by the small cross-sectional area of the gas discharge holes 24 and, on the other hand, by the stack valve 13 and the torch, irrespective of the position of the valve 13 relative to the prechamber 23 . Since a small radial clearance remains with the inner wall of the ignition prechamber 23, it increases more rapidly.

The constituent gases of the main charge 30 have substantially no passageway other than the gas discharge holes 24 to go from the combustion chamber 5 to the stacking cavity 6 .

Since the gas discharge holes 24 leave only a passage portion limited to said gas, the difference between the pressure acting on the cavity side surface 14 and the pressure acting on the chamber side surface 15 increases, which causes the stack valve 13 to against the valve closing seat 18 with which it cooperates. This situation is clearly shown in FIG.

The time required for the laminated valve 13 to break the contact it forms with the valve opening seat 20 with which it cooperates on the one hand, and to make contact with the valve closing seat 18 on the other hand, is determined by a few degrees of rotation of the crankshaft 37, or Corresponding to only 1 or 2 degrees of rotation, these values are given for information only.

In doing so, the lamination valve 13 closes the lamination duct 7 and the combustion chamber 5 no longer communicates with the lamination cavity 6 . The ever-increasing pressure in the combustion chamber 5 due to the upward movement of the piston 31 in the cylinder 4 no longer affects the pressure in the stacking cavity 6, said pressure remaining stable.

A few crankshaft degrees after the laminate valve 13 closes the laminate duct 7 , the laminate injector 8 begins to inject the pilot charge 9 into the laminate cavity 6 . This situation is illustrated in FIG. The temperature of the constituent gas charge 9 is about 80 degrees according to this example.

A few crankshaft degrees after the laminate valve 13 closes the laminate duct 7 , the laminate injector 8 begins to inject the pilot charge 9 into the laminate cavity 6 . This situation is illustrated in FIG. The temperature of the constituent gases of the charge 9 is, according to this example, about 80 degrees.

The flow velocity of the injector is calculated so that the pressure in the laminated cavity 6 remains always lower than the pressure in the combustion chamber 5, so that the laminated valve 13 cooperates with the valve through its cavity-side valve support surface 19. It never leaves the closing sheet 18 .

At crankshaft 37 a few degrees before top dead center of piston 31, the pressure in combustion chamber 5 and to which main charge 30 is exposed reached nearly 40 bar, while the pressure in lamination cavity 6 reached 20 bar. . The stack injector 8 stops injecting the pilot charge 9 into the stack cavity 6 .

As shown in FIG. 6, a high voltage current is applied to the terminal end of spark plug 12 when piston 31 reaches near its top dead center. A spark plug 12 ignites a pilot charge 9 held within the stack cavity 6 .

Furthermore, it is noted that a pressure of only 20 bar in said cavity 6 allowed only moderate voltages to be applied to the end of the spark plug 12 .

As shown in FIG. 6, the pilot charge 9 consists of a combustible combustible-AF fuel mixture, and the flame initiated by the spark plug 12 propagates very rapidly through the pilot charge 9 and its temperature , like the pressure in the stacking cavity 6, rises rapidly as well.

When the pressure reaches for example 45 bar, ie 5 bar higher than the pressure in the combustion chamber 5, the stack valve 13 has already moved 15/100 millimeters. In doing so, the valve 13 moves out of contact with the valve closing seat 18 and rests on the valve opening seat 20 . This situation is also illustrated in FIG.

In this process, the laminated valve 13 gradually exposes the gas discharge holes 24 and hot gas (eg, heated to a temperature of about 2,000° C.) passes through the torch ignition prechamber 23 and at the protruding discharge dome 25. , began to be emitted from the lamination cavity 6 in the form of a torch through said hole 24 . This effect provided by the valve ignition prechamber 1 according to the invention is illustrated in FIG.

As the pressure in the stacking cavity 6 continues to rise, the pressure in said cavity 6 is 20 bar higher than the pressure in the combustion chamber 5 . As a result, the pressure of the hot gases drops by 20 bar while passing through the gas discharge holes 24, thereby reducing their temperature to about 1,300 degrees. In exchange, the gases are moved at high speed, which allows them to penetrate deeply into the volume of combustion chamber 5 .

In doing so, the hot gases ignite the surrounding gases that make up the main charge 30 . In addition to releasing the fuel energy they contain into heat, the ambient gases are moved by the hot gas at high local velocities, which embodies in the form of microturbulence. The folding of the flame front resulting from the above microturbulence promotes the development of combustion, which propagates rapidly throughout the main charge 30 and the entire combustion chamber 5 volume.

The efficiency of the valve ignition prechamber 1 according to the present invention in developing said combustion because the hot gas torch formed all around the protruding discharge dome 25 ignites the main charge 30 at multiple locations within the combustion chamber 5. is noted to be quite high.

Indeed, once initiated radially from the center of the combustion chamber 5 to the periphery, the combustion of the charge material 30 proceeds from the periphery of the combustion chamber 5 to the periphery of the combustion chamber 5 in a second stage. It develops radially towards the center and tangentially between each hot torch exiting the protruding discharge dome 25 through the gas discharge holes 24 .

When the combustible-AF fuel mixture comprising the pilot charge 9 is completely combusted and largely discharged in the form of hot gas jets through the gas discharge holes 24, combustion develops in the combustion chamber 5 and The pressure in chamber 5 rises faster than the pressure in lamination cavity 6 .

Also, as soon as this situation is reached, the chamber-side face 15 of the stack valve 13 is subjected to a pressure greater than the pressure acting on the cavity-side face 14 of said valve 13 . Laminated valve 13 is then rapidly moved 15/100 millimeters towards laminated cavity 6 and is pressed firmly against the cooperating valve closure seat 18 . This situation is illustrated in FIG.

Since the combustion of the main charge 30 occurs very quickly despite the high "cooled EGR" content of the main charge 30, said combustion occurs only after the piston 31 reaches top dead center. Complete in just a few degrees of 37. Therefore, the thermodynamic efficiency of the internal combustion engine 2 can reach its maximum level, because while expansion has barely started, the entire energy contained in the constituent fuel of the main charge 30 has already been released. because he fell.

As shown in FIG. 7, the stack valve 13 remains closed while the piston 31 begins its expansion stroke, converting most of the heat of the high temperature burned gases of the main charge 30 into useful work. start. This work is transmitted to the crankshaft 37 by the piston 31 via the connecting rod 38 .

By doing so, the pressure and temperature in the combustion chamber 5 are gradually lowered. When the pressure reaches, for example, 60 bar, the pressure remaining in the stacking cavity 6 will be higher than the pressure in the combustion chamber 5 .

As a result of this situation, the valve seat 21 on the chamber side of the stack valve 13 returns to contact with the valve opening seat 20, as shown in FIG. The stack valve 13 again fully exposes the gas discharge hole 24 through which the residual hot gases of the pilot charge 9 are expanded by the piston 31 during continued expansion of the main charge 30. is released.

When the piston 31 reaches the bottom dead center, the exhaust valve 35 is opened, and after the gas finishes expanding in the exhaust duct 33, the piston 31 moves upward in the cylinder 4 toward the top dead center. is actively pushed back into the duct 33 by .

During the exhaust stroke of piston 31 , stack cavity 6 can finish exhausting residual hot gases from pilot charge 9 via gas discharge holes 24 . This discharge can also continue during the intake phase which, according to the normal sequence, marks the start of a new four-stroke cycle designed/conceived by Otto/Baud de Rochas.

As can be seen throughout the description presented, unlike known devices according to the state of the art, the valve ignition prechamber 1 according to the invention allows limiting the injection pressure of the pilot charge 9 to approximately 20 bar.

This relatively low pressure not only makes it possible to limit the energy consumption of the laminate compressor 36, but also limits its complexity in that a single compression stage is sufficient to reach said pressure. made it possible.

Furthermore, only 1.6% of the fuel contained in the main charge 30 contributes to the strong ignition of the charge 30 (approximately 200 times stronger than conventional spark ignition), as well as the three dimensions of the combustion chamber 5 where the ignition is It was enough to ensure that it occurred at multiple locations evenly distributed in space.

Both the low compression pressure of the pilot charge 9 on the one hand and the small amount of combustible-AF fuel mixture contained in said charge 9 on the other hand are consumed by the laminated compressor 36 to compress said pilot charge 9. contributes to minimizing the energy consumed.

This therefore makes it possible to minimize the amount of work that the laminated compressor 36 applies directly or indirectly to the crankshaft 37 of the internal combustion engine 2, which maximizes the final energy efficiency of said engine 2. contributes to becoming

Furthermore, the time allowed for the lamination injector 8 to inject the pilot charge 9 into the lamination cavity 6 depends on the compression phase of the internal combustion engine 2 according to the four-stroke cycle designed/conceived by Otto/Baud de Rochas. It is noted that the allotted time is approximately equivalent. This made it possible, on the one hand, to limit the required dynamics of the injector 8 and, on the other hand, to limit the supply pressure of the injector 8 . This in particular contributes to reducing the cost and complexity of the injector 8, while giving it greater reliability and durability.

It is noted that during the entire injection of the pilot charge material 9 into the stacking cavity 6, said charge material 9 was mixed with only a very small amount of residual combustion gases. The content of the combustion gases in the charge 9 before spark ignition is only about 1/1000, which is extremely low.

As a result of this, the pilot charge 9 maintains maximum flammability, which combined with a pressure of only 20 bar when the spark plug 12 ignites said charge 9, allows said spark to obtain said ignition. It made it possible to limit the voltage applied to the end of the plug 12 . As a result, power consumption for supplying power to the spark plug 12 is reduced, and the durability of the spark plug 12 is increased.

During the sequence of operations shown in successive steps in FIGS. 3-8, the thermal load on the protruding discharge dome 25 is applied to any state-of-the-art ignition prechamber (such a prechamber lacking a laminated valve 13). is reduced to the minimum necessary in that the hot gas passes through the gas discharge holes 24 only once, as compared to three times.

Due to this peculiarity, the dome tends to rise to excessively high temperatures, causing untimely and uncontrolled ignition of the main charge material leading to rattling and damage or even destruction of the internal combustion engine 2. It has become possible in particular to prevent the formation of hot spots. Furthermore, the protruding discharge dome 25 remains cool, making it possible to provide a high compression ratio for the internal combustion engine 2 without the risk of rattling.

Therefore, the valve ignition prechamber 1 according to the invention provides a spark that operates under a high rate of cooled EGR regardless of the load and rotational speed of the internal combustion engine 2 and without sacrificing their combustion stability. It makes it possible to manufacture an ignition internal combustion engine 2 .

As a result of the high ratio of EGR, the intake pressure of the internal combustion engine 2 is naturally higher at part load than that of an internal combustion engine 2 of the same design operating without cooled EGR. This reduces the pumping losses caused by modulation of the load by the intake pressure, said modulation being actuated, for example, by a butterfly.

Furthermore, an internal combustion engine 2 receiving a valve ignition prechamber 1 according to the invention reduces heat losses as well as the amount of nitrogen oxides per kilowatt-hour produced by said internal combustion engine 2 . This is due to the possibility provided by the valve ignition prechamber 1 according to the invention to introduce a high proportion of cooled EGR into said charge 30. Combustion of the main charge 30 occurs at a lower average temperature. derived from the facts.

In this situation it is to be expected that the compression ratio of the internal combustion engine 2, made possible by the valve ignition prechamber 1 according to the invention, will be higher than that of the same engine operating without rattle and without cooled EGR. can be done. This is favorable for the efficiency of the internal combustion engine 2 described above.

Furthermore, the reduction in pumping losses and heat losses provided by the valve ignition prechamber 1 according to the invention significantly reduces the displacement of the internal combustion engine 2 with ISO torque and ISO power by adding supercharging, for example by turbocharging. Reducing the need is noted. In fact, it is possible to reduce or even eliminate supercharging while maintaining high energy performance compared to the state of the art.

As a result of this set of properties and advantages provided by the valve ignition prechamber 1 according to the present invention, the affordable cost, low fuel consumption, low carbon dioxide emissions and post-treatment of the pollutants by a simple three-way catalyst It becomes possible to obtain a guaranteed internal combustion engine 2 .

It is noted that the valve ignition prechamber 1 according to the invention can be applied in other fields than internal combustion engines. The prechamber 1 can be applied, for example, to gas nailers, firearms, or any device that requires combustion of a main charge by a pilot charge with the best possible efficiency.

The possibilities of the valve ignition prechamber 1 according to the invention are not restricted to the applications described, the preceding description is given only as an example and is used instead of the embodiments described here. It should also be understood not to limit the scope of the above invention, which would cover any other equivalent embodiments.

Claims (14)

A valve ignition prechamber for an internal combustion engine (2) with a cylinder head (3) capping the cylinder (4) to form a combustion chamber (5) in which the main charge (30) can be burned 1) and
at least one cavity (6) arranged in said cylinder head (3) on the one hand and connected to said combustion chamber (5) by a duct (7) and on the other hand preceded by compression means (10) receiving an injector (8) capable of directly or indirectly injecting a pressurized pilot charge (9) into said cavity (6), said pilot charge (9) being readily combustible by a spark; at least one cavity (6) consisting of a combustible-fuel mixture;
igniting means (11) opening into said cavity (6) and capable of igniting said pilot charge (9);
The duct (7) can be closed in whole or in part, exposing on the one hand the cavity-side face (14) exposed to the pressure of the gas in the cavity (6) and on the other hand the combustion chamber (5). ), the valve (13) exposing a chamber-side face (15) exposed to the pressure of the gas in the cavity, if the pressure in the cavity is lower than the pressure in the combustion chamber (5), the cavity towards (6) or towards said combustion chamber (5) if the pressure in said combustion chamber is lower than that in said cavity (6) into said duct (7) under the influence of said gas pressure. a valve (13) translatable relative to;
at least one cavity-side valve stop (16) that determines the position of the valve (13) closest to the cavity (6);
at least one chamber-side valve stop (17) that determines the position of the valve (13) closest to the combustion chamber (5);
said chamber-side valve stopper (17) comprising a valve opening seat (20) located within said duct (7) or at either end of said duct (7), said valve opening seat (20) and said valve (13), together with said duct (7), with said cavity (6) on the one hand and said combustion chamber (5) on the other hand, when the chamber -side valve support surfaces (21) are in contact with each other; , forming a torch ignition prechamber (23) simultaneously communicating via at least one gas discharge hole (24). The valve (13) closes all or part of the duct (7) when it is closest to the cavity (6), while when it is positioned closest to the combustion chamber (5). 2. Valve ignition prechamber according to claim 1, characterized in that the duct (7) is open in its wider part. Said cavity-side valve stopper (16) comprises a valve closing seat (18) located within said duct (7) or at either end of said duct (7), said valve closing seat (18) comprising: 2. Valve ignition prechamber according to claim 1, characterized in that it cooperates with a cavity-side valve support surface (19) arranged around and/or at the end of the valve (13). Said valve closing seat (18) and said cavity-side valve support surface (19) form a seal when in contact with each other, said seal allowing the pressure in said combustion chamber (5) to 4. Valve ignition prechamber according to claim 3, characterized in that it prevents the passage of any gas when the pressure therein is higher. characterized in that said valve opening seat (20) and said chamber-side valve support surface (21) form a seal when in contact with each other, thereby preventing the passage of any gas, A valve ignition prechamber according to claim 1. said valve (13) is positioned approximately centrally within said duct (7) and with said duct (7) regardless of the axial position of said valve (13) relative to said duct (7); 2. A valve ignition prechamber according to claim 1, characterized in that it is provided with guide means (22) around its periphery which maintain substantially the same longitudinal orientation. wherein said valve (13) has a circular outer periphery and is housed within said torch ignition prechamber (23) with radial clearance, while the inner peripheral wall of said torch ignition prechamber (23) is cylindrical; 2. A valve ignition prechamber as claimed in claim 1. Said duct (7) projects into said combustion chamber (5) in the form of a protruding discharge dome (25) which houses said torch ignition prechamber (23) and from which said gas discharge holes (24) open. 2. A valve ignition prechamber according to claim 1, characterized in that it is open. 9. Valve ignition prechamber according to claim 8, characterized in that the valve opening seat (20) is arranged in the protruding discharge dome (25). when said valve (13) is arranged near said combustion chamber (5), i.e. when it is arranged close to or in contact with said chamber-side valve stopper (17) with which it cooperates, said valve 2. Valve ignition prechamber according to claim 1, characterized in that (13) exposes at least one gas discharge hole (24) connecting said cavity (6) with said combustion chamber (5). said ignition means (11) consists of a spark plug (12) closing a first end of a perforated connecting tube (26), said perforated connecting tube (26) being the internal volume of said cavity (6) and its body is radially traversed by at least one radial slot (27) connecting the interior of said perforated connecting tube (26) to said interior volume, while said The second end of the perforated connecting tube (26) receives said duct (7) and said valve (13), while the center electrode (40) and ground electrode (39) of said spark plug (12) are connected. A valve ignition prechamber according to claim 1, characterized in that it is housed in the perforated connecting tube (26). 2. Valve ignition prechamber according to claim 1, characterized in that the cavity-side surface (14) exposes an aerodynamic dome (29). Said cavity-side face (14) forms a ground electrode (39) facing a center electrode (40) contained in a spark plug (12), said spark plug (12) constituting ignition means (11). The valve ignition prechamber according to claim 1, characterized in that: Claim characterized in that said valve (13) is axially thicker at its perimeter which receives said cavity-side valve support surface (19) and said chamber-side valve support surface (21) than at its center. 4. A valve ignition prechamber according to item 3.

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