method for injecting a gaseous oxidant-fuel mixture

Abstract

METHOD FOR INJECTING A GAS-FUEL OXIDIZING MIXTURE The method for injecting a gas-fuel-oxidizing mixture (1) of a pilot charge (39) into an ignition pre-chamber (2) consists of measuring the angular position of a crankshaft (7), then using a filling electrical current profile (22) that imposes a filling lift law (23) on a gas-fuel mixture injector (9) that opens into said pre-chamber (2), using an overlap variable (25) that fixes the offset between the ignition (41) of the pilot charge (39) in the ignition pre-chamber (2) and the end of the injection of said charge (39), using a trigger variable for the filling electrical current profile (26), using a mixture variable (27), and this in order to generate for each operating point of an internal combustion engine (4) an injection data set (28), then to execute said game (28). Figure for the abbreviation: Fig. 1

Description

Title of the invention: Method for injecting a gaseous oxidizer-fuel mixture

[0001] The present invention relates to a method of injecting a gaseous oxidizer-fuel mixture into an ignition pre-chamber, said method allowing the energy and power of combustion of said mixture in said pre-chamber to be regulated, in order to maximize the thermodynamic efficiency of an internal combustion engine, to reduce its pollutant emissions, to facilitate its starting at all temperatures, and to improve its dynamic, acoustic, and vibratory behavior.

[0002] The maximum effective efficiency of reciprocating internal combustion heat engines used in automobiles is around thirty-eight percent for Otto cycle spark-ignition engines, and around forty percent for Diesel cycle engines.

[0003] As regards the average efficiency in normal use of said engines, it is most often less than twenty-five percent for spark-ignition engines, and thirty percent for Diesel engines, which leads to significant greenhouse gas emissions and an accelerated depletion of fossil energy resources, mainly petroleum.

[0004] In addition to low efficiency, said engines produce polluting gases and fine particles harmful to the environment and health.

[0005] Despite these unfavorable characteristics, due to a lack of alternative solutions offering a better compromise in energy, environment, functionality, and economy, internal combustion engines with Otto or Diesel cycles equip the vast majority of motor vehicles in circulation worldwide.

[0006] The supremacy of internal combustion engine vehicles comes from the fact that they are cheap to produce, can be recharged in a few minutes, offer long ranges, and mainly consume oil, that is to say an abundant energy distributed at low cost almost everywhere on the planet.

[0007] However, in view of the risks that oil resources pose to the climate and to the energy sovereignty of oil-importing countries, the states of many countries discourage motorists from buying internal combustion engine cars by surtaxing them, and encourage said motorists to buy electric vehicles by means of purchase subsidies.

[0008] Despite this state interventionism, the electrification of the automobile is encountering resistance from motorists who are reluctant to buy electric cars, even Subsidized, they remain more expensive than their thermal counterparts, have more limited range, and take longer to recharge.

[0009] In addition to these obstacles to the development of electric cars, there is often problematic access to a charging point at home or at work, an uncertain resale value, high repair and insurance costs, and a mixed ecological and environmental assessment over the entire life cycle.

[0010] In addition, the significant pressure exerted by the "all-electric" strategy on mineral resources and on electricity production makes projections on the actual future penetration of electric cars uncertain.

[0011] Taking into account the uncertainties regarding the future of the electric car, and the growing environmental and energy constraints, the improvement of the energy efficiency of reciprocating internal combustion engines appears essential, due to the large market share occupied by said engines and their strong potential for commercial deployment.

[0012] Alongside said improvement, the development of low carbon or carbon-neutral fuels such as electrofuels produced from green hydrogen and carbon dioxide directly captured from the atmosphere seems to be the way forward, in addition to the production of a sustainable share of biofuels from biomass.

[0013] One of the most effective strategies for increasing the efficiency of reciprocating internal combustion engines with spark ignition is to equip them with ignition pre-chambers known per se, generally one per cylinder.

[0014] The ignition pre-chambers are provided to emit, via ignition torch emission orifices, high-temperature ignition torches into the main combustion chamber of said engines, in the form of turbulent jets, to ignite a main charge composed of air and fuel contained in said chamber.

[0015] The ignition torches release an ignition energy several hundred to several thousand times greater than that delivered by a spark produced between the electrodes of a spark plug, and said torches deploy at high speed in the internal three-dimensional volume of the combustion chamber, generating vigorous local turbulence as they pass, all of which causes rapid and efficient combustion of the main charge.

[0016] To obtain this result, a pilot charge is introduced into the ignition pre-chamber either in whole or in part through the ignition torch emission orifices, or in whole or in part through an injector which opens into said pre-chamber, or through both, before being ignited by a spark plug known per se, which also opens into said pre-chamber.

[0017] To be effective in igniting the main charge and ensuring rapid combustion conducive to the efficiency of the heat engine, the pilot charge must be highly flammable and reactive, that is to say, contain few residual burnt gases from the previous cycle.

[0018] This necessity gives full interest to the pre-chamber ignition with flap that is the subject of the patent belonging to the applicant published on July 19, 2018 under number WO2018 / 130772, and to its main improvements whose patents, which also belong to the applicant, have been published in particular under Nos WO2020053501 and WO2022 / 079367, said flap separating the internal volume of the pre-chamber from that of the main chamber.

[0019] Unlike the pilot charge which must remain pure, the main charge must be diluted with a gas which does not participate in the combustion but which reduces the average temperature of the gases during the combustion of said main charge, reduces the production of nitrogen oxides, and increases the intake pressure of the heat engine which promotes its efficiency at partial loads.

[0020] Thus diluted, the main charge limits heat losses to the internal walls of the main combustion chamber, which is also favorable to the energy efficiency of the heat engine.

[0021] Ideally, the main charge should be diluted with a non-reactive gas which allows the heat engine to operate at stoichiometry, and which acts as a knock moderator to prevent any detonating combustion of the main charge, which would be destructive to said engine.

[0022] Moderating knocking makes it possible to fix a high compression ratio of the heat engine which promotes its energy efficiency, and to set the combustion of the main charge of said engine at the optimum of efficiency, these two actions reducing the energy consumption of said engine for the same work produced.

[0023] The most obvious way to dilute the main charge with an additional non-reactive gas is to add to the internal combustion engine an exhaust gas recirculation device called "EGR", which is the acronym for the Anglo-Saxon term "Exhaust Gas Recirculation", this in order to both maintain a stoichiometric main charge, and to moderate knocking.

[0024] A stoichiometric main charge is required to post-treat the pollutants that were produced during the combustion of the main charge by means of a trifunctional catalyst, the latter being notoriously efficient, economical, and widely used in automobiles and throughout the world.

[0025] Indeed, pre-ignition chamber engines that operate with a lean mixture and are therefore non-stoichiometric and run with excess air, require a complex and expensive device for post-treatment of nitrogen oxides by selective catalytic reduction.

[0026] The efficiency of these spark-ignition engines is comparable to that of equivalent Diesel engines, and they have the same pollutant aftertreatment constraints, so producing them is not worthwhile.

[0027] In practice, only pre-ignition chamber engines operating at stoichiometry and whose main charge is diluted at the EGR are of real commercial interest due to their high efficiency on the one hand, and the possibility of post-treating pollutants by means of a simple three-way catalyst on the other.

[0028] However, such engines require that a fuel mixture - and not a fuel alone unlike engines operating in excess of oxygen - be introduced into their ignition pre-chamber, said mixture having preferably been pre-prepared before its introduction into said pre-chamber so as to have the desired fuel richness, and to be perfectly homogeneous.

[0029] The prior preparation of said fuel mixture is the objective of the forced recirculation mixer, the patent of which belonging to the applicant was published on November 4, 2021 under No. WO2021219943, said mixer cooperating with a source of pressurized air such as a compressor known per se.

[0030] Said fuel mixture is then introduced into the ignition pre-chamber by an injector whose nose opens into said pre-chamber.

[0031] It is observed that the way in which the injector injects said fuel mixture has a strong impact on the course of combustion in the pre-ignition chamber and, by cascade effect, on the course of combustion in the main combustion chamber of the internal combustion engine.

[0032] In particular, the turbulence which is animated by the fuel mixture in the ignition pre-chamber has strong consequences on the combustion speed of said mixture in said pre-chamber, and on the ejection speed of the ignition torches in the main combustion chamber.

[0033] In this respect, if the spark plug ignites the fuel mixture in said pre-chamber while the mixture injector has finished injecting, the turbulence of said mixture is low and its combustion speed is slow.

[0034] In this case, the ignition torches are ejected at low speed into the main chamber which avoids excessive overmixing of said hot torches with the cold main charge, and avoids extinction of the nascent flame and misfire of said charge, particularly when it is diluted with EGR.

[0035] If, on the contrary, the spark plug ignites the fuel mixture in said pre-chamber while the mixture injector is injecting, the turbulence of said mixture is strong, as is its combustion speed.

[0036] In this case, the ignition torches are ejected at high speed into the main chamber to ignite reactive main charges either diluted with fresh air or slightly diluted at the EGR, for example when the internal combustion engine is running at high speed and moderate load, and to burn said main charges in a minimum time which makes it possible to avoid knocking and to deliver a high thermodynamic efficiency.

[0037] However, excessive slowness or speed of combustion of the pilot charge impairs the efficiency of the heat engine, and the energy and power of combustion of the pilot charge should ideally always be adapted to the nature of the main charge and the operating conditions of said engine.

[0038] Taking into account the above, it is observed that the way in which the mixture injector introduces the pilot charge into the ignition pre-chamber has a direct consequence in particular on the efficiency and / or the torque and power performance of the internal combustion engine.

[0039] Indeed, the same quantity of pilot charge can be introduced into the ignition pre-chamber over a longer or shorter period depending on whether the injector is partially open at low flow for a long time or is kept fully open at high flow for a short time, all variants between these two extremes being possible.

[0040] Therefore, the method and means used to inject the pilot charge relative to the ignition of said charge are crucial for the energy efficiency of the internal combustion engine on the one hand, and for the quantity of pollutants produced by said engine on the other hand, as well as for the stability and the acoustic and vibration emissions of said engine.

[0041] In this respect, the method for injecting a gaseous oxidizer-fuel mixture according to the invention can be applied to any internal combustion heat engine with an ignition pre-chamber, provided that the latter receives an injector for a homogeneous gaseous mixture of fuels, said method allowing in particular the adjustment of the quantity, energy and combustion speed of said mixture in said pre-chamber, which allows, according to a particular embodiment of said method: • To maximize the energy efficiency of said engine regardless of its operating point, whether said engine is operating at a stabilized or transient speed-load, in cold start, in temperature transient, in hot operation, and over the entire torque and power range; • To minimize the amount of pollutants produced by the combustion of the main charge in the main combustion chamber of said engine; • To optimize the operation of pollutant after-treatment devices that cooperate with said engine; • To optimize the stability of said engine and to better control its acoustic and vibration emissions; • In general, to optimize the efficiency of the pilot load to produce the desired effects on the combustion of the main load.

[0042] To achieve these objectives, the method of injecting a gaseous oxidizer-fuel mixture according to the invention makes it possible, from a set of measurable parameters, to apply to the terminals of an electrically controlled injection actuator of a gaseous oxidizer-fuel mixture injector, an injector electrical current profile such that said actuator imposes on an injector needle that includes said injector a filling lift law which makes it possible, among other things and simultaneously, to regulate the quantity of a gaseous oxidizer-fuel mixture introduced into an ignition pre-chamber as a pilot charge, and to regulate the combustion rate of said mixture.

[0043] It is understood that the method of injecting a gaseous oxidizer-fuel mixture according to the invention is intended, in addition to reciprocating internal combustion heat engines, for any other application similar in its concept and principle which could advantageously take advantage of the particular characteristics and functionalities of said injection method according to the invention.

[0044] The other features of the present invention have been described in the description and in the secondary claims directly or indirectly dependent on the main claim.

[0045] The method of injecting a gaseous oxidizer-fuel mixture according to the present invention into an ignition pre-chamber comprising a cylinder head of a spark-ignition reciprocating internal combustion engine, said pre-chamber having at least one ignition torch emission orifice opening into a main combustion chamber comprising said engine and into which a main charge consisting of an oxidizer and a fuel can be introduced, said engine also comprising at least one crankshaft, at least one camshaft, and at least one gaseous fuel mixture injector opening into the ignition pre-chamber, said injector comprising at least one injector needle which can either rest in a sealed manner on a needle seat, said injector being then closed, or,to be lifted from said seat by an electrically controlled injection actuator controlled by a computer, said injector then being open, which has the effect of introducing into said pre-chamber a pilot charge consisting of a gaseous fuel mixture which is made up of an oxidizer and a fuel and which has been previously pressurized by means of compression, said mixture having been formed in an oxidizer-fuel mixer while the ignition of the pilot charge, The ignition in the pre-chamber can be triggered by the computer by means of a spark plug that opens into said pre-chamber, and consists of: • Measure, using a crankshaft angular position sensor, the crankshaft angular position CA to transmit to the computer the crankshaft angular position relative to that of the internal combustion engine; • Use at least one electrical filling current profile that can be applied by the computer to electrical supply terminals of the electrically controlled injection actuator, said profile being intended to impose on the injector needle a filling lift law from which follows, on the one hand, the temporal evolution of the position of said needle relative to that of the needle seat with which it cooperates, and on the other hand, a filling opening time of the gaseous fuel mixture injector; • Use an overlap variable that fixes the offset between, on the one hand, the angular position of the crankshaft CA at the time of ignition of the pilot charge in the pre-ignition chamber by the spark plug, and on the other hand, the angular position of the crankshaft CA at the time of the injector needle resting on the needle seat with which it cooperates; • Use a trigger variable for the electrical current profile of filling which sets, as a function of the overlap variable, the crankshaft angular position CA from which the computer applies the electrical current profile of filling to the electrical supply terminals of the electrically controlled injection actuator, said trigger variable being calculated by said computer, on the one hand, from the crankshaft angular position CA where the ignition of the pilot charge in the pre-ignition chamber is triggered by the computer, and on the other hand, from the filling opening time of the gaseous fuel mixture injector which is imposed by the electrical current profile of filling; • Use a richness variable that sets the mass proportion of oxidizer and fuel that make up the gaseous fuel mixture constituting the pilot charge produced by the oxidizer-fuel mixer; • Generate, for each engine operating point, an injection data set that includes a filling current profile, a value assigned to the recovery variable, a value assigned to the filling current profile trigger variable, and a value assigned to the mixture variable; said data set determines the quantity, composition, and turbulence of the gaseous fuel mixture constituting the pilot charge at the moment of ignition of said mixture, which determines the speed of combustion of said mixture in the pre-ignition chamber on the one hand, and the thermal power released by said combustion on the other hand; • Execute the injection data set corresponding to the operating point of the internal combustion engine.

[0046] The method for injecting a gaseous fuel mixture according to the present invention consists of: • Use a sweep electrical current profile trigger variable that fixes an angular position of the AC crankshaft; • Apply, to the crankshaft angular position CA resulting from the trigger variable of the electrical current scavenging profile and via the computer, an electrical current scavenging profile to the electrical supply terminals of the electrically controlled injection actuator, said scavenging profile being intended to impose on the injector needle a scavenging lift law from which, on the one hand, the temporal evolution of the position of said needle relative to the needle seat, and on the other hand, a scavenging opening duration of the gaseous fuel mixture injector is derived.

[0047] The method for injecting a gaseous fuel mixture according to the present invention consists of: • Measure, using an injector needle position sensor, the distance d between the injector needle and the needle seat to transmit said distance d to the computer in real time; • Correct the electrical current profile for filling if it does not lead, on the one hand, to the filling lift law of the injector needle, and on the other hand, to the filling opening time of the gaseous fuel mixture injector, as originally provided by said profile.

[0048] The method for injecting a gaseous fuel mixture according to the present invention consists of: • Measure, using an injector needle position sensor, the distance d between the injector needle and the needle seat to transmit said distance d to the computer in real time; • Correct the electrical current scanning profile if it does not lead, on the one hand, to the injector needle sweep lift law, and on the other hand, to the gaseous fuel mixture injector sweep opening duration, as originally provided by said profile.

[0049] The method for injecting a gaseous fuel mixture according to the present invention consists of: • Measure the pressure p in the ignition pre-chamber using a pre-chamber pressure sensor to transmit said pressure p to the computer in real time; • Correct the electrical current profile of the filling injector if said profile does not lead to a pre-chamber filling pressure profile as it should be taking into account the operating conditions of the internal combustion engine.

[0050] The method of injecting a gaseous fuel mixture according to the present invention comprises a lift-filling flow conversion model which determines, from the operating conditions of the internal combustion engine, from the filling lift law, and from the pressure measured by a pressure sensor and the temperature measured by a temperature sensor of the gaseous fuel mixture to be introduced into the ignition pre-chamber by the gaseous fuel mixture injector, a mass flow rate of gaseous fuel mixture filling constituting the pilot charge which is actually introduced by said injector into said pre-chamber.

[0051] The method of injecting a gaseous fuel mixture according to the present invention comprises a scavenging lift-flow conversion model which determines, from the operating conditions of the internal combustion engine, from the scavenging lift law, and from the pressure measured by a pressure sensor and the temperature measured by a temperature sensor of the gaseous fuel mixture to be introduced into the ignition pre-chamber by the gaseous fuel mixture injector, a mass flow rate of scavenging gaseous fuel mixture which is actually introduced by said injector into said pre-chamber.

[0052] The method of injecting a gaseous fuel mixture according to the present invention comprises a filling electric current profile, a recovery variable, a richness variable, an injection data set, a slewing profile and a trigger variable for the slewing electric current profile which are stored in the computer's memory and / or calculated in real time by the latter.

[0053] The method for injecting a gaseous fuel mixture according to the present invention consists of: • Measure, using a camshaft angular position sensor, the CSA camshaft angular position to transmit to the computer the angular position of the camshaft relative to that of the internal combustion engine; • Use the CSA camshaft angular position to determine at which crankshaft revolution of the internal combustion engine is affected the trigger variable of the filling electrical current profile and the trigger variable of the scavenging electrical current profile.

[0054] The other features of the present invention have been described in the description and in the secondary claims directly or indirectly dependent on the main claim.

[0055] The following description, with reference to the attached drawings given by way of non-limiting examples, will allow for a better understanding of the invention, its features, and the advantages it is likely to provide:

[0056] [Fig-1] is a schematic representation of the method of injecting a gaseous oxidizer-fuel mixture according to the invention and a schematic cross-section of the internal combustion engine and its accessories to which said method applies.

[0057] DESCRIPTION OF THE INVENTION:

[0058] [Fig.1] The method of injecting a gaseous oxidizer-fuel mixture 1 according to the invention, various details of its components, its variants, and its accessories have been shown.

[0059] Fig. 1 shows that the method of injecting a gaseous oxidizer-fuel mixture 1 according to the invention applies to an ignition pre-chamber 2 comprising a cylinder head 3 of a reciprocating internal combustion engine 4 with spark ignition, said pre-chamber 2 being designed to emit ignition torches in the form of hot gases.

[0060] The ignition pre-chamber 2 has at least one ignition torch emission orifice 5 which opens into a main combustion chamber 6 which comprises the internal combustion engine 4 and into which a main charge 40 consisting of an oxidizer 15 and a fuel 16 can be introduced.

[0061] The internal combustion engine 4 also includes at least one crankshaft 7, at least one camshaft 8, and at least one gaseous fuel mixture injector 9 which opens into the ignition pre-chamber 2.

[0062] The gaseous fuel mixture injector 9 includes at least one injector needle 10 which can either rest in a sealed manner on a needle seat 11, the said injector 9 being then closed, or be lifted from the said seat 11, that is to say be held at a distance from the said seat 11, by an electrically controlled injection actuator 12 controlled by a computer 13, the latter being made up of one or more separate or non-separate modules.

[0063] The electrically controlled injection actuator 12 can be direct or indirect controlled, and of electromagnetic, piezoelectric, electro-hydraulic, electro-pneumatic type, and with staged or non-staged control.

[0064] When the gaseous fuel mixture injector 9 is open, it introduces into the ignition pre-chamber 2 a pilot charge 39 formed of a gaseous fuel mixture 14 which is as homogeneous as possible and which consists of, on the one hand, an oxidizer 15 such as atmospheric air, and on the other hand, a fuel 16 such as, for example, gasoline, ethanol, hydrogen or methane.

[0065] Before being introduced into the ignition pre-chamber 2 by the gaseous fuel mixture injector 9, the gaseous fuel mixture 14 constituting the pilot charge 39 has been previously pressurized by compression means 17 consisting for example of a piston compressor, vane compressor or any other type known to those skilled in the art, said mixture 14 having been formed in an oxidizer-fuel mixer 18 which may be a carburetor, a mixer such as that described in patent WO2021219943 belonging to the applicant, or any other mixing device known or not to those skilled in the art.

[0066] The ignition 41 of the pilot charge 39 in the ignition pre-chamber 2 can be triggered by the computer 13 by means of a spark plug 19 which opens into said pre-chamber 2, and more specifically in most cases by a spark produced between the electrodes of said spark plug 19.

[0067] It has been shown in [Fig.1] that the method of injecting a gaseous oxidant-fuel mixture 1 according to the invention consists of measuring, by means of a crankshaft angular position sensor 20, the crankshaft angular position CA in order to transmit to the computer 13 the crankshaft angular position 7 relative to that of the internal combustion engine 4.

[0068] The crankshaft angular position sensor 20 can consist of an angular encoder or a phonic wheel known per se.

[0069] The method of injecting a gaseous oxidizer-fuel mixture 1 according to the invention also consists of using at least one electrical filling current profile 22 of variable intensity and therefore of variable voltage as a function of time, said profile 22 being able to be applied by the computer 13 to electrical supply terminals 36 which are present in the electrically controlled injection actuator 12.

[0070] The electrical filling current profile 22 is intended to impose on the injector needle 10 a filling lift law 23 from which follows, on the one hand, the temporal evolution of the position of said needle 10 relative to that of the needle seat 11 with which it cooperates, and on the other hand, a filling opening time 24 of the gaseous fuel mixture injector 9.

[0071] The filling lift law 23 can take an infinite number of forms, while the filling opening time 24 of the gaseous fuel mixture injector 9 can advantageously be expressed as an angular sector of crankshaft rotation 7 during which the injector needle 10 is open and introduces fuel mixture. gaseous 14 in the ignition prechamber 2, said filling lift law 23 and said filling opening duration 24 being adapted to each operating point of the internal combustion engine 4 to serve, separately or jointly, objectives of efficiency, pollutant emission and dynamic performance of said engine 4.

[0072] As shown in [Fig.1], the method of injecting a gaseous oxidizer-fuel mixture 1 according to the invention also consists of using at least one overlap variable 25 which fixes the offset between, on the one hand, the angular position of the crankshaft CA at the time of the ignition 41 of the pilot charge 39 in the pre-ignition chamber 2 by the spark plug 19, and on the other hand, the angular position of the crankshaft CA at the time of the repositioning of the injector needle 10 on the needle seat 11 with which it cooperates, said offset being able to be expressed for example in degrees of rotation of the crankshaft 7.

[0073] The recovery variable 25 can be positive and in this case, the ignition 41 of the pilot charge 39 in the ignition pre-chamber 2 occurs while the injector needle 10 is still lifted from the needle seat 11, or negative, the ignition 41 of the pilot charge 39 in said pre-chamber 2 occurring only after the injector needle 10 has returned to contact with the needle seat 11.

[0074] The recovery variable 25 is mainly intended to adapt the level of turbulence of the gaseous fuel mixture 14 present in the ignition pre-chamber 2 at the time of its ignition 41, in order to regulate the combustion speed of the pilot charge 39 thus constituted, and with the objective of optimizing the efficiency and power, and limiting the polluting emissions of the internal combustion engine 4 according to the operating point of the latter, and according to the objectives associated with this point.

[0075] Fig. 1 also illustrates that the method of injecting a gaseous oxidant-fuel mixture 1 according to the invention also uses a trigger variable of the filling electrical current profile 26 which sets, as a function of the recovery variable 25, the crankshaft angular position CA from which the computer 13 applies the filling electrical current profile 22 to the electrical supply terminals 36 of the electrically controlled injection actuator 12.

[0076] The triggering variable of the electrical current profile of filling 26 is calculated by said computer 13, on the one hand, from the angular position of crankshaft CA where the ignition 41 of the pilot charge 39 in the pre-ignition chamber 2 is triggered by the computer 13 via the spark plug 19, and on the other hand, from the filling opening time 24 of the gaseous fuel mixture injector 9 which is imposed by the electrical current profile of filling 22.

[0077] In [Fig. 1], it has also been shown that the method of injecting a gaseous oxidizer-fuel mixture 1 according to the invention uses a richness variable 27 expressed for example in grams of fuel per gram of oxidizer, which fixes the mass proportion of oxidizer 15 and fuel 16 which makes up the gaseous fuel mixture 14 constituting the pilot charge 39 produced by the oxidizer-fuel mixer 18, the computer 13 being able to control said mixer 18 to achieve said proportion.

[0078] Fig. 1 also shows that the method of injecting a gaseous oxidizer-fuel mixture 1 according to the invention generates, for each operating point of the engine 4, an injection data set 28 which includes a filling electrical current profile 22, a value assigned to the recovery variable 25, a value assigned to the triggering variable of the filling current profile 26, and a value assigned to the richness variable 27.

[0079] The injection data set 28 fixes the quantity, composition and turbulence of the gaseous fuel mixture 14 constituting the pilot charge 39 at the time of ignition 41 of said mixture 14, which determines the rate of combustion of said mixture 14 in the pre-ignition chamber 2 on the one hand, and the thermal power released by said combustion on the other hand.

[0080] It is noted that, generally, the more the ignition 41 of the gaseous fuel mixture 14 in the ignition pre-chamber 2 takes place when the injector needle 10 is further from the needle seat 11 and the flow rate of gaseous fuel mixture 14 entering said pre-chamber 2 is greater, the higher the rate of combustion of said mixture 14.

[0081] As shown in [Fig.1], the method of injecting a gaseous oxidant-fuel mixture 1 according to the invention can consist of using a triggering variable of the electrical current scanning profile 45 which fixes an angular position of the crankshaft CA.

[0082] In this case, the method of injecting a gaseous oxidant-fuel mixture 1 according to the invention also consists of applying to the crankshaft angular position CA resulting from the triggering variable of the electrical current scanning profile 45 and via the computer 13, an electrical current scanning profile 29 to the electrical supply terminals 36 of the electrically controlled injection actuator 12 said scanning profile 29 preceding the electrical current filling profile 22.

[0083] In this case, the electrical sweep current profile 29 is designed to impose on the injector needle 10 a sweep lift law 32, from which follows, on the one hand, the temporal evolution of the position of said needle 10 relative to the seat needle 11, and on the other hand, a scavenging opening time 33 of the gaseous fuel mixture injector 9.

[0084] It is noted that the sweep-off law 32 aims to sweep the ignition pre-chamber 2 with fresh gaseous fuel mixture 14, and to replace the burnt gases resulting from the previous combustion with said fresh mixture 14.

[0085] Fig. 1 also shows that the method of injecting a gaseous oxidant-fuel mixture 1 according to the invention can consist of measuring, by means of an injector needle position sensor 30, the distance d between the injector needle 10 and the needle seat 11 in order to transmit said distance d in real time to the computer 13.

[0086] In this case and according to this variant, the method of injecting a gaseous oxidant-fuel mixture 1 according to the invention consists of correcting the filling electrical current profile 22 if the latter does not lead, on the one hand, to the filling lift law 23 of the injector needle 10, and on the other hand, to the filling opening time 24 of the gaseous fuel mixture injector 9, as originally provided by said profile 22 and this, as long as said law 23 and said time 24 are not sufficiently close to what is originally provided by said profile 22.

[0087] As shown in [Fig.1], the method of injecting a gaseous oxidizer-fuel mixture 1 according to the invention can also consist of measuring, by means of a prechamber pressure sensor 34, the pressure p which prevails in the ignition prechamber 2, in order to transmit said pressure p in real time to the computer 13.

[0088] In this case, the method of injecting a gaseous oxidant-fuel mixture 1 according to the invention consists of correcting the electrical current profile of the filling injector 22 if said profile 22 does not lead to a filling pressure profile of the prechamber 35 such as it should be taking into account the operating conditions of the internal combustion engine 4 and this, as long as said pressure profile 35 is not sufficiently close to what it should be.

[0089] This last variant is particularly relevant if the ignition pre-chamber 2 receives a valve according to patent No. WO2018 / 130772 belonging to the applicant, said variant being able to apply identically to the electric sweep current profile 29.

[0090] As another variant shown in [Fig. 1], the method for injecting a gaseous oxidizer-fuel mixture 1 according to the invention may include a lift-filling flow conversion model 37 which determines, from the operating conditions of the internal combustion engine 4, from the filling lift law 23, and from the pressure measured by a pressure sensor 31 and the temperature measured by a temperature sensor 42 of the gaseous fuel mixture 14 to be introduced into the ignition pre-chamber 2 by the gaseous fuel mixture injector 9, a constitutive mass flow rate of the gaseous fuel mixture filling 38 of the pilot charge 39 which is actually introduced by said injector 9 into said prechamber 2.

[0091] Said flow 38 can then be transmitted to the oxidizer-fuel mixer 18 so that the latter can adjust the proportion of fuel 16 to be introduced into the oxidizer 15 to make the gaseous fuel mixture 14.

[0092] Similarly and as illustrated in [Fig. 1], the method of injecting a gaseous oxidizer-fuel mixture 1 according to the invention may include a scavenging lift-flow conversion model 49 which determines, from the operating conditions of the internal combustion engine 4, from the scavenging lift law 32, and from the pressure measured by a pressure sensor 31 and the temperature measured by a temperature sensor 42 of the gaseous fuel mixture 14 to be introduced into the ignition prechamber 2 by the gaseous fuel mixture injector 9, a mass flow rate of scavenging gaseous fuel mixture 50 which is actually introduced by said injector 9 into said prechamber 2.

[0093] As before, the result obtained is then transmitted to the oxidizer-fuel mixer 18 so that the latter can produce a mixture of oxidizer 15 and fuel 16 in the desired proportions.

[0094] As a variant of the method of injecting a gaseous oxidant-fuel mixture 1 according to the invention, the electrical current profile of filling 22, the recovery variable 25, the richness variable 27, the injection data set 28, the scavenging profile 29 and the trigger variable of the electrical current profile of scavenging 45 can be recorded in the memory of the computer 13 and / or calculated in real time by the latter.

[0095] As another variant, the method of injecting a gaseous oxidant-fuel mixture 1 according to the invention can measure from a camshaft angular position sensor 21 the camshaft angular position CSA to transmit to the computer 13 the angular position of the camshaft 8 relative to that of the internal combustion engine 4.

[0096] Having done this and still according to this last variant, the method of injecting a gaseous oxidant-fuel mixture 1 according to the invention uses the angular position of the camshaft CSA to determine at which crankshaft revolution of the internal combustion engine 4 is affected the triggering variable of the filling electrical current profile 26 and the triggering variable of the scavenging electrical current profile 45, this being necessary if the thermodynamic cycle of the internal combustion engine 4 takes place over more than one crankshaft revolution 7.

[0097] OPERATION OF THE INVENTION:

[0098] The operation of the process of injecting a gaseous oxidant-fuel mixture 1 according to the invention can be easily understood from [Fig.1].

[0099] In [Fig. 1] and by way of non-limiting example, the method of injecting a gaseous oxidizer-fuel mixture 1 according to the invention has been shown as advantageously applicable to a reciprocating internal combustion engine 4 with spark ignition which includes a crankshaft 7, two camshafts 8 and a cylinder head 3, the latter forming, with a cylinder 46 and a piston 47, a main combustion chamber 6 into which an intake valve 48 can introduce a main charge 40 consisting of a mixture made of an oxidizer 15 and a fuel 16.

[0100] It can be seen in [Fig.1] that a crankshaft angular position sensor 20 measures the crankshaft angular position CA to transmit in real time to a computer 13 also noted "ECU" the angular position of the crankshaft 7 relative to that of the internal combustion engine 4.

[0101] Said engine 4 performing, according to this example, a four-stroke Otto thermodynamic cycle known per se, a camshaft angular position sensor 21 measures the camshaft angular position CSA and transmits to the computer 13 the angular position of one of the two camshafts 8 relative to that of said engine 4, which allows said computer 13 to distinguish the crankshaft revolution 7 where the compression and expansion of the Otto cycle take place, from the crankshaft revolution 7 where the exhaust and intake take place.

[0102] In [Fig.1], it has been shown that the method of injecting a gaseous oxidizer-fuel mixture 1 according to the invention is intended for an internal combustion engine 4 whose cylinder head 3 houses an ignition pre-chamber 2 into which, on the one hand, the electrodes of a spark plug 19 open, and on the other hand, the nose of a gaseous fuel mixture injector 9 which can introduce into said pre-chamber 2 a gaseous fuel mixture 14 denoted “AF”, the latter forming a pilot charge 39.

[0103] In [Fig.1], it is noted that before being introduced into the ignition pre-chamber 2, the gaseous fuel mixture 14 was pressurized by compression means 17 such as a piston, screw, vane compressor or any type known to those skilled in the art, and was formed in an oxidizer-fuel mixer 18 such for example as the forced recirculation mixer which is the subject of patent No. WO2021219943 belonging to the applicant, from an oxidizer 15 also noted "A", and a fuel 16 also noted "F".

[0104] It can be seen in [Fig.1] that the ignition pre-chamber 2 opens into the main combustion chamber 6 via ignition torch emission orifices 5 which connect said pre-chamber 2 with said chamber 6, so that when the pilot charge 39 is ignited by the spark plug 19 in said pre-chamber 2, ignition torches, not shown in said [Fig.1], are emitted in the main combustion chamber 6 in the form of high-temperature gases already burned, or in the process of combustion.

[0105] The said ignition torches have the function of igniting the main charge 40 by providing it with a thermal and turbulent energy much higher than that ordinarily delivered by a simple spark plug.

[0106] This ignition strategy, known by the Anglo-Saxon term "Turbulent Jet ignition" from which the acronym "TJI" is derived, allows the combustion of the main charge 40 to be initiated at multiple points in the volume of the main combustion chamber 6, while generating strong local turbulence which puckers the flame front and promotes rapid and complete combustion of said main charge 40.

[0107] Associated with a pilot charge 39 pre-prepared by means of an oxidizer-fuel mixer 18, said strategy makes it possible to efficiently ignite any main charge 40, even if the latter is made of a fuel-lean mixture 16 compared to stoichiometry, or if said charge 40 is close to stoichiometry but highly diluted with exhaust gases recirculated according to the strategy known by the Anglo-Saxon acronym "EGR", the lean mixture and the dilution to "EGR" both requiring high ignition powers.

[0108] Let us recall here that the combustion of lean fuel mixtures 16 or of highly diluted mixtures at 1' "EGR" which allows the "TJI" ignition strategy makes it possible to significantly increase the thermodynamic efficiency of internal combustion engines 4 thanks, at least, to a reduction of the heat losses at the internal walls of said engine 4, to a moderation of the sensitivity to knocking of the introduced fuel mixture forming the main charge 40 which makes it possible to increase the compression ratio of said engine 4 and to optimize the angular timing of the combustion, and to a reduction of pumping losses at the intake of said engine 4.

[0109] If, in addition, the ignition pre-chamber 2 is equipped with a stratification valve such as that described in patent WO2018 / 130772 belonging to the applicant and in the resulting improvement patents published in particular under Nos. WO2020053501 and WO2022 / 079367, it is possible to produce internal combustion engines 4 with high energy efficiency and low emissions, which are capable of meeting the functional requirements of a modern hybrid or non-hybrid automobile, and which emit few regulated or unregulated pollutants.

[0110] It is easily deduced from the above that the way in which the combustion of the pilot charge 39 in the pre-ignition chamber 2 takes place determines the way in which the combustion of the main charge 40 takes place in the main combustion chamber 6.

[0111] In particular, the amount of energy contained in the pilot charge 39 and the speed at which this energy is released determine whether or not the main charge 40 is burned under optimal conditions.

[0112] For example, if the combustion of the pilot charge 39 is too rapid, there may be overmixing of the hot ignition torches with the cold main charge 40, which leads to inefficient combustion of said charge 40, or even to a misfire of said charge 40.

[0113] If, on the contrary, the combustion of the pilot charge 39 is too slow and / or too low in energy, the combustion of the main charge 40 may also be too slow or even incomplete, which leads to a lower efficiency of the internal combustion engine 4 and to high pollutant emissions.

[0114] These considerations are closely linked to the "TJI" ignition strategy, particularly when the latter is applied to internal combustion engines 4 subjected to large variations in torque, speed and power, and to infinitely variable operating conditions, which is for example the case of automotive internal combustion engines 4.

[0115] This largely explains why, despite its many advantages, the "TJI" ignition strategy has long been applied to industrial internal combustion engines operating at fixed speed and load, but not to internal combustion engines dedicated to automotive propulsion.

[0116] For indeed, in an automotive internal combustion engine 4, the energy and ignition power of the main charge 40 which must be delivered by the combustion of the pilot charge 39 in the form of ignition torches must ideally vary constantly, in parallel with the operating conditions of the internal combustion engine 4.

[0117] Meeting this hitherto unmet need to control the energy and ignition power of the main charge 40 according to the conditions of the internal combustion engine 4 is made possible by the method of injecting a gaseous oxidizer-fuel mixture 1 according to the invention, and this, all the more effectively if said method 1 cooperates with an ignition pre-chamber 2 equipped with a stratification valve such as that described in patent WO2018 / 130772.

[0118] To achieve this result, the method of injecting a gaseous oxidant-fuel mixture 1 according to the invention offers all the necessary levers to effectively control the combustion conditions of the pilot charge 39 and this, to obtain a combustion of said charge 39 close to ideal both with regard to the energy released by said combustion, and with regard to the speed at which said energy is released, that is to say the power of said combustion.

[0119] It is noted that inside the ignition pre-chamber 2, the gaseous fuel mixture 14 which forms the pilot charge 39 is subjected to turbulence resulting from its introduction into said pre-chamber 2 by the gaseous fuel mixture injector 9, said mixture 14 bathing the electrodes of the spark plug 19.

[0120] Now, it is noted that the intensity of said turbulence has a direct impact on the ability of said spark plug 19 to ignite 41 of the pilot charge 39, and on the development of the combustion of said charge 39 in the pre-ignition chamber 2.

[0121] If the intensity of said turbulence is too low, the combustion of the pilot charge 39 initiated between the electrodes of the spark plug 19 may be too slow to develop, while if said intensity is too high, said combustion may eventually begin, but with a high risk of being extinguished by blowing out the nascent flame.

[0122] However, insofar as we remain within a level of turbulence compatible with the ignition 41 of the pilot charge 39 by the spark plug 19, we note that a high intensity turbulence leads to a faster combustion of said charge 39 than a lower intensity turbulence, which affects the rate of release of the energy contained in said charge 39 and therefore, the power released by the combustion of said charge 39 to ignite the main charge 40 via ignition torches.

[0123] Now, the intensity of the turbulence to which the pilot charge 39 is subjected at the time of its ignition 41 in the ignition pre-chamber 2 by the spark plug 19 is in particular dependent on the time lag between the moment of said ignition 41 and the moment when said charge 39 is introduced into said pre-chamber 2 by the injector of gaseous fuel mixture 9.

[0124] Because indeed, during the introduction of the pilot charge 39 into the ignition pre-chamber 2 by the gaseous fuel mixture injector 9, the pressure of the gaseous fuel mixture 14 upstream of said injector 9 is greater than the pressure prevailing in the ignition pre-chamber 2.

[0125] As a result, the gaseous fuel mixture 14 entering said prechamber 2 is agitated with a more or less intense turbulence, the latter decreasing rapidly once the gaseous fuel mixture injector 9 is closed.

[0126] As such, the longer the delay between the end of the injection of the pilot charge 39 and its ignition 41, the less intense the turbulence of the gaseous fuel mixture 14 constituting said charge 39 in the ignition pre-chamber 2 is at the time of said ignition 41, the slower the combustion of the pilot charge 39, and the lower the power delivered by said combustion for the purpose of igniting the main charge 40.

[0127] On the contrary, if the ignition 41 of the pilot charge 39 is triggered by the spark plug 19 while the injection of said charge 39 into the ignition pre-chamber 2 is not completed, said ignition 41 takes place in a context of intense turbulence of the gaseous fuel mixture 14 constituting said charge 39, the combustion of the pilot charge 39 is rapid, and the power delivered by said combustion for the purpose of igniting the main charge 40 is high.

[0128] This is why the method of injecting a gaseous oxidizer-fuel mixture 1 according to the invention uses an overlap variable 25 which fixes, from the crankshaft angular position CA, the negative or positive crankshaft angular offset 7 between, on the one hand, the moment of ignition 41 of the pilot charge 39 in the ignition pre-chamber 2 by the spark plug 19, and on the other hand, the resting of the injector needle 10 on its needle seat 11, said resting marking the end of the introduction of the pilot charge 39 into the ignition pre-chamber 2 by the gaseous fuel mixture injector 9.

[0129] There is therefore a direct link between the value of the recovery variable 25 on the one hand, and the intensity of the turbulence of the gaseous fuel mixture 14 constituting said charge 39 at the time of its ignition 41 on which depends the power of the combustion of said charge 39 delivered for the purpose of igniting the main charge 40 on the other hand.

[0130] In other words, if the ignition 41 of the pilot charge 39 occurs at a crankshaft angular position CA of a few degrees, for example ten or twenty degrees, earlier than the crankshaft angular position CA at which the injector needle 10 returns to rest on its needle seat 11, the ignition 41 and the introduction of the pilot charge 39 into the ignition prechamber 2 take place simultaneously, and said charge 39 is subjected to high intensity turbulence at the time of said ignition 41.

[0131] If, on the contrary, the ignition 41 of the pilot charge 39 occurs at a crankshaft angular position CA of a few degrees, for example three to ten degrees, later than the crankshaft angular position CA at which the injector needle 10 returns to rest on its needle seat 11, the ignition 41 of the pilot charge 39 occurs only after the introduction of said charge 39 into the ignition pre-chamber 2 has been completed, there is then no longer any overlap between said ignition 41 and the introduction of the pilot charge 39 into the ignition pre-chamber 2, and said charge 39 is subjected only to a turbulence of lesser intensity at the time of said ignition 41.

[0132] In addition to the overlap between the ignition 41 and the introduction of the pilot charge 39 into the pre-ignition chamber 2 which conditions the intensity of the turbulence to which the gaseous fuel mixture 14 constituting the pilot charge 39 is subjected at the time of its ignition 41, it is noted that said intensity is all the greater as the flow rate of gaseous fuel mixture 14 delivered by the gaseous fuel mixture injector 9 is high at the time of said ignition 41.

[0133] Therefore, the way in which the same mass of pilot charge 39 is introduced into the ignition prechamber 2 by the gaseous fuel mixture injector 9 also determines the intensity of the turbulence to which the gaseous fuel mixture 14 constituting said charge 39 is subjected at the time of its ignition 41 by the spark plug 19.

[0134] Said manner is defined by the filling lift law 23, which is itself determined by the filling electrical current profile 22 applied by the computer 13 to the electrical supply terminals 36 of the electrically controlled injection actuator 12.

[0135] For example, to introduce the same mass of pilot charge 39 into the ignition pre-chamber 2, the injector needle 10 can rise from its needle seat 11 a lot but briefly so as to generate a turbulence of high intensity but brief, or on the contrary rise a little but for a long time, thus generating a turbulence of less intensity over a longer time.

[0136] There are therefore an infinite number of possibilities for adjusting the intensity of the turbulence which is animated by the pilot charge 39 at the moment of its ignition 41 by the spark plug 19, whatever the mass of said pilot charge 39, and whatever the energy contained in said charge 39.

[0137] This is why the method of injecting a gaseous oxidant-fuel mixture 1 according to the invention provides on the one hand, an electric filling current profile 22 which can take an infinite number of forms and which can lead to an infinite number of filling lifting laws 23, and on the other hand, a recovery variable 25 which can take an infinite number of values ​​and from which a triggering variable of the filling current profile 26 is derived.

[0138] The combination formed by the angular position of the crankshaft CA at the time of ignition 41 of the pilot charge 39, by the electrical current profile of filling 22, and by the recovery variable 25, allows the energy, power and timing of the ignition of the main charge 40 in the pre-ignition chamber 2 to be adjusted simultaneously.

[0139] By combining different values ​​assigned to the recovery variable 25 with different filling electric current profiles 22 leading to different filling lifting laws 23, the method of injecting a gaseous oxidizer-fuel mixture 1 according to the invention therefore makes it possible to choose in all circumstances with what energy and what power released by the combustion of the pilot charge 39 is ignited the main charge 40 of a spark-ignited internal combustion engine 4.

[0140] This freedom allows said engine 4 to be operated under the most favorable conditions for high thermodynamic efficiency, minimal emissions, and a optimal dynamic, acoustic and vibrational operation, particularly if the ignition pre-chamber 2 of said engine 4 is equipped with a stratification valve such as that described in patent WO2018 / 130772 belonging to the applicant.

[0141] Among the operating circumstances of the internal combustion engine 4, we can mention the idle speed and load, intermediate speeds and loads, speed and load transients, full load, full power, as well as starting at low or even very low temperatures, the warm-up phase of the pollutant aftertreatment catalyst, and in general, all the points and modes of operation of an internal combustion engine 4, whether automotive or dedicated to any other application, without limitation.

[0142] As can be seen in [Fig.1], to further optimize the combustion of the pilot charge 39 and optionally, the method of injecting a gaseous oxidizer-fuel mixture 1 according to the invention provides for a trigger variable of the electrical current scanning profile 45 which corresponds to an angular position of the crankshaft CA to which the computer 13 applies an electrical current scanning profile 29 to the electrical supply terminals 36 of the electrically controlled injection actuator 12.

[0143] The electric current scanning profile 29 results in imposing on the injector needle 10 a scavenging lift law 32 which precedes the filling lift law 23, for example by some degrees of crankshaft rotation 7.

[0144] During the entire duration of the scavenging opening 33 which results from it and which takes place when the pressure in the main combustion chamber is low, the gaseous fuel mixture injector 9 introduces into the pre-ignition chamber 2 a small quantity of gaseous fuel mixture 14 which has the function of expelling the residual burnt gases from the previous cycle so that when the introduction of the pilot charge 39 itself follows, the latter is as pure as possible and as little diluted as possible by the said burnt gases.

[0145] Indeed, avoiding diluting the pilot charge 39 with residual burnt gases from the previous cycle makes said charge 39 more reactive and easier to ignite by the spark plug 19, the latter then being more durable because it is sufficient to deliver less electrical energy between its electrodes, while the combustion of the pilot charge 39 is more stable from one cycle to the next.

[0146] The use of a triggering variable of the electric sweep current profile 45 and the sweep lift law 32 associated with it is all the more effective if the method of injecting a gaseous oxidizer-fuel mixture 1 according to the invention is applied to an ignition pre-chamber 2 equipped with a stratification valve such as that described in patent WO2018 / 130772.

[0147] As the fuel richness of the gaseous fuel mixture 14 constituting the pilot charge 39 also plays a predominant role in the combustion speed of said charge 39 in the pre-ignition chamber 2 and in the efficiency of said charge 39 in igniting the main charge 40, the method of injecting a gaseous oxidizer-fuel mixture 1 according to the invention incorporates a richness variable 27.

[0148] Indeed, depending on the fuel richness 16 of the gaseous fuel mixture 14 constituting the pilot charge 39, during the combustion of the latter, the gases ejected at high temperature from the pre-ignition chamber 2 to the main combustion chamber 6 via the ignition torch emission ports 5 can contain more or less hydroxyl radicals, carbon monoxide or unburned hydrocarbons, these chemical species playing a predominant role on the efficiency and kinetics of the combustion of the main charge 40.

[0149] It will also be noted that the fuel richness 16 of the gaseous fuel mixture 14 also has a strong influence on the combustion rate of the pilot charge 39 in the ignition prechamber 2, knowing that a fuel richness 16 of the order of one point two to one point three times the stoichiometry constitutes a good compromise in most cases.

[0150] Therefore, taking into account the above, the method of injecting a gaseous oxidizer-fuel mixture 1 according to the invention provides for grouping the main parameters influencing the combustion of the pilot charge 39 in the ignition pre-chamber 2 in the form of an injection data set 28 which is written in the memory of the computer 13 and / or which is calculated in real time by the latter.

[0151] Said set 28 comprises, for each operating point of the internal combustion engine 4, a filling electrical current profile 22, a value assigned to the recovery variable 25, a value assigned to the triggering variable of the filling current profile 26, and a value assigned to the richness variable 27, to which may be added a triggering variable of the scavenging electrical current profile 45 and a scavenging electrical current profile 29.

[0152] Thus, the injection data set 28 fixes the quantity, composition and turbulence of the gaseous fuel mixture 14 constituting the pilot charge 39 at the time of ignition 41 of said mixture 14, which determines the rate of combustion of said mixture 14 in the pre-ignition chamber 2, the thermal power released by said combustion, the chemical species emitted in the main combustion chamber 6 and therefore, the efficiency of said combustion in igniting the main charge 40 in the main combustion chamber 6 and in promoting as rapid and complete a combustion as possible of said main charge 40.

[0153] The possibilities of the method of injecting a gaseous oxidant-fuel mixture 1 according to the invention are not limited to the applications which have just been described and it must also be understood that the preceding description has been given only by way of example and that it does not in any way limit the field of said invention which would not be exceeded by replacing the details of execution described by any other equivalent.

Claims

1. Demands Method of injecting a gaseous oxidizer-fuel mixture (1) into an ignition pre-chamber (2) comprising a cylinder head (3) of a reciprocating spark-ignition internal combustion engine (4), said pre-chamber (2) having at least one ignition torch emission orifice (5) opening into a main combustion chamber (6) comprising said engine (4) and into which a main charge (40) consisting of an oxidizer (15) and a fuel (16) can be introduced, said engine (4) also comprising at least one crankshaft (7), at least one camshaft (8), and at least one gaseous oxidizer-fuel mixture injector (9) opening into the ignition pre-chamber (2), said injector (9) comprising at least one injector needle (10) which can either rest in a sealed manner on a needle seat (11), said injector (9) being then closed, or,to be lifted from said seat (11) by an electrically controlled injection actuator (12) controlled by a computer (13), said injector (9) then being open, which has the effect of introducing into said pre-chamber (2) a pilot charge (39) formed of a gaseous fuel mixture (14) which consists of an oxidizer (15) and a fuel (16) and which has been previously pressurized by compression means (17), said mixture (14) having been formed in an oxidizer-fuel mixer (18), while the ignition (41) of the pilot charge (39) in the ignition pre-chamber (2) can be triggered by the computer (13) by means of a spark plug (19) which opens into said pre-chamber (2), characterized in that it consists of:, • Measure, using a crankshaft angular position sensor (20), the crankshaft angular position (CA) to transmit to the computer (13) the crankshaft angular position (7) relative to that of the internal combustion engine (4); • Use at least one electrical filling current profile (22) that can be applied by the control unit (13) to electrical supply terminals (36) present on the electrically controlled injection actuator (12), said profile (22) being designed to impose on the injector needle (10) a filling lift law (23) of which on the one hand, there follows the temporal evolution of the position of said needle (10) relative to that of the needle seat (11) with which it cooperates, and on the other hand, a filling opening time (24) of the gaseous fuel mixture injector (9); Use an overlap variable (25) which fixes the offset between, on the one hand, the crankshaft angular position (CA) at the time of ignition (41) of the pilot charge (39) in the ignition pre-chamber (2) by the spark plug (19), and on the other hand, the crankshaft angular position (CA) at the time of the injector needle (10) resting on the needle seat (11) with which it cooperates; Use a trigger variable of the electrical filling current profile (26) which sets, as a function of the recovery variable (25), the crankshaft angular position (CA) from which the computer (13) applies the electrical filling current profile (22) to the electrical supply terminals (36) of the electrically controlled injection actuator (12), said trigger variable (26) being calculated by said computer (13), on the one hand, from the crankshaft angular position (CA) where the ignition (41) of the pilot charge (39) in the pre-ignition chamber (2) is triggered by the computer (13), and on the other hand, from the filling opening time (24) of the gaseous fuel mixture injector (9) which is imposed by the electrical filling current profile (22); Use a richness variable (27) which fixes the mass proportion of oxidant (15) and fuel (16) which make up the gaseous fuel mixture (14) constituting the pilot charge (39) produced by the oxidant-fuel mixer (18); Generate for each engine operating point (4) an injection data set (28) which includes a filling electrical current profile (22), a value assigned to the recovery variable (25), and a value assigned to the profile trigger variable. of filling current (26), and a value assigned to the richness variable (27), said set (28) fixing the quantity, composition and turbulence of the gaseous fuel mixture (14) constituting the pilot charge (39) at the time of ignition (41) of said mixture (14), which determines the speed of combustion of said mixture (14) in the pre-ignition chamber (2) on the one hand, and the thermal power released by said combustion on the other hand; • Execute the injection data set (28) corresponding to the operating point of the internal combustion engine (4).

2. A method for injecting a gaseous fuel mixture according to claim 1, characterized in that it consists of: • Using a trigger variable of the electrical current scanning profile (45) which fixes a crankshaft angular position (CA); • Applying, to the crankshaft angular position (CA) resulting from the trigger variable of the electrical current scanning profile (45) and via the computer (13), an electrical current scanning profile (29) to the electrical supply terminals (36) of the electrically controlled injection actuator (12), said scanning profile (29) being provided to impose on the injector needle (10) a scavenging lift law (32) from which, on the one hand, the temporal evolution of the position of said needle (10) relative to the needle seat (11) is derived, and on the other hand, a scavenging opening duration (33) of the gaseous fuel mixture injector (9).

3. A method for injecting a gaseous fuel mixture according to claim 1, characterized in that it consists of: • Measuring, by means of an injector needle position sensor (30), the distance (d) between the injector needle (10) and the needle seat (11) in order to transmit said distance (d) in real time to the computer (13); • Correcting the electrical current profile of the filling (22) if the latter does not lead, on the one hand, to the filling lift law (23) of the injector needle (10), and on the other hand, to the filling opening time (24) of the gaseous fuel mixture injector (9), as originally provided for by said profile (22).

4. Method of injecting a gaseous fuel mixture according to claim 2, characterized in that it consists of: • Measuring by means of an injector needle position sensor (30) the distance (d) between the injector needle (10) and the needle seat (11) in order to transmit said distance (d) in real time to the computer (13); • Correcting the electrical current scavenging profile (29) if the latter does not lead, on the one hand, to the scavenging lift law (32) of the injector needle (10), and on the other hand, to the scavenging opening duration (33) of the gaseous fuel mixture injector (9), as originally provided by said profile (29).

5. Method of injecting a gaseous fuel mixture according to claim 1, characterized in that it consists of: • Measuring by means of a prechamber pressure sensor (34) the pressure (p) which prevails in the ignition prechamber (2) in order to transmit said pressure (p) in real time to the computer (13); • Correcting the electrical current profile of the filling injector (22) if said profile (22) does not lead to a prechamber filling pressure profile (35) such as it should be taking into account the operating conditions of the internal combustion engine (4).

6. A method for injecting a gaseous fuel mixture according to claim 1, characterized in that it comprises a lift-to-fill rate conversion model (37) which determines, from the operating conditions of the internal combustion engine (4), from the lift-to-fill rate law (23), and from the pressure measured by a pressure sensor (31) and the temperature measured by a temperature sensor (42) of the gaseous fuel mixture (14) to be introduced into the ignition pre-chamber (2) by the gaseous fuel mixture injector (9), a mass flow rate of the gaseous fuel mixture filling (38) constituting the charge pilot (39) which is actually introduced by said injector (9) into said prechamber (2).

7. A method for injecting a gaseous fuel mixture according to claim 2, characterized in that it comprises a lift-flow scavenging conversion model (49) which determines, from the operating conditions of the internal combustion engine (4), from the lift scavenging law (32), and from the pressure measured by a pressure sensor (31) and the temperature measured by a temperature sensor (42) of the gaseous fuel mixture (14) to be introduced into the ignition pre-chamber (2) by the gaseous fuel mixture injector (9), a mass flow rate of gaseous fuel mixture scavenging (50) which is actually introduced by said injector (9) into said pre-chamber (2).

8. Method of injecting a gaseous fuel mixture according to any one of claims 1 and 2, characterized in that the filling electric current profile (22), the recovery variable (25), the richness variable (27), the injection data set (28), the scavenging profile (29) and the scavenging electric current profile trigger variable (45) are stored in the computer memory (13) and / or calculated in real time by the latter.

9. A method for injecting a gaseous fuel mixture according to any one of claims 1 and 2, characterized in that it consists of: • Measuring, by means of a camshaft angular position sensor (21), the camshaft angular position (CSA) to transmit to the computer (13) the camshaft angular position (8) relative to that of the internal combustion engine (4); • Using the camshaft angular position (CSA) to determine at which crankshaft revolution of the internal combustion engine (4) the trigger variable of the filling electrical current profile (26) and the trigger variable of the scavenging electrical current profile (45) is assigned.

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