Patent Grant
11293385
The present invention relates to a forced recirculation mixer essentially designed to mix at least one liquid and at least one gas in determined proportions, and over a wide range of mass flow.
Said mixer according to the present invention is particularly suitable for the implementation of the valve-controlled ignition pre-chamber which was the subject of patent No. FR 3,061,743 published on Aug. 16, 2019, said patent belonging to the applicant.
Said pre-chamber is so designed that a pilot charge is injected into a stratification cavity by a stratification injector, said charge being in the majority of cases and particularly in the automotive industry consisting of a readily-inflammable air-gasoline mixture which has previously been pressurized by compression means.
The invention according to patent FR 3,061,743 is in fact particularly intended for the automotive market. However, said market is very sensitive to the cost price, weight and size of any equipment, which must remain as low as possible. The automotive market is also very demanding in terms of robustness, reliability, service life, and maintenance.
This is the context in which the valve-controlled ignition pre-chamber according to patent FR 3,061,743 falls, said pre-chamber requiring both high metering precision of the air-gasoline mixture which constitutes the pilot charge, and a high quality of preparation of said mixture which must be as homogeneous as possible.
However, the preparation of said mixture takes place at a relatively high pressure of the order of forty or fifty bars, while the flow rate of the air with which the gasoline must be mixed is very low, which flow rate of air can vary in intensity in a ratio of one hundred and fifty, or even more.
In addition, it is essential that the gasoline is fully vaporized in the air which receives it before introducing the resulting air-gasoline mixture into the stratification cavity by means of the stratification injector.
It is also essential to prevent any partial re-condensation of gasoline despite the high pressure to which the air-gasoline mixture is subjected; said re-condensation may occur if the homogeneity of said mixture is insufficient.
In fact, the quality of the combustion of the pilot charge in the stratification cavity depends both on its composition and in particular on the air/gasoline ratio of the mixture to be burned, and on its homogeneity.
It is therefore primarily to implement the valve-controlled ignition pre-chamber according to patent FR 3,061,743 that, according to a particular embodiment, the forced recirculation mixer according to the invention:
It is to be understood that the forced recirculation mixer according to the invention can not only be applied to the valve-controlled ignition pre-chamber according to patent FR 3,061,743, but also to any other application, whatever the type or the field, which requires mixing at least one gas with at least one liquid in precise proportions and in a homogeneous manner, regardless of said gas or said liquid.
The forced recirculation mixer according to this invention is designed to mix at least one vaporizable liquid with at least one gas to be mixed so as to form a homogeneous gaseous mixture, said mixer comprising:
The forced recirculation mixer according to the present invention comprises at least one external coaxial duct, each end of which is closed by a reversing terminating end, at least one internal coaxial duct being accommodated in the external coaxial duct and a gap being left for the homogeneous gas mixture to circulate, on the one hand, between each reversing terminating end and the internal coaxial duct and, on the other hand, between the inner face of the external coaxial duct and the outer face of the internal coaxial duct, the direction of circulation of the homogeneous gas mixture in the external coaxial duct being opposite to the direction of circulation of said mixture in the internal coaxial duct.
The forced recirculation mixer according to the present invention comprises a stirring turbine which is wholly or partly accommodated in one of the reversing terminating ends, the homogeneous gas mixture being sucked through the center of said turbine via the internal coaxial duct before being discharged to the periphery of said turbine via the gap left between the inner face of the external coaxial duct and the outer face of the internal coaxial duct.
The forced recirculation mixer according to the present invention comprises a reversing terminating end which accommodates the stirring turbine which has a hollow hemi-toroidal shape, and blades which comprises the stirring turbine having a complementary protruding hemi-toroidal shape, a small play being left between said terminating end and said blades.
The forced recirculation mixer according to the present invention comprises a gas inlet duct which passes through one of the reversing terminating ends to emerge into the internal coaxial duct.
The forced recirculation mixer according to the present invention comprises a reversing terminating end crossed by the gas inlet duct which has a hollow hemi-toroidal shape from which said duct emerges.
The forced recirculation mixer according to the present invention comprises a liquid injection nozzle which emerges into the interior of the gas inlet duct, or at the outlet thereof.
The forced recirculation mixer according to the present invention comprises an internal coaxial duct which is held in position in the external coaxial duct by at least one stirring vane which radially connects said internal coaxial duct to said external coaxial duct.
The forced recirculation mixer according to this invention comprises an external coaxial conduit or any of the reversing terminating ends thereof, which is wholly or partly surrounded by a draw-off ring, the inside of the latter being connected to the inside of the external coaxial duct by at least one radial draw-off orifice, the mixture draw-off duct being connected to the stirring enclosure by means of said ring and said orifice.
The forced recirculation mixer according to the present invention includes a stirring enclosure which includes heating or cooling means.
The forced recirculation mixer according to the present invention comprises a turbine motor which is an electric motor which comprises, on the one hand, a rotor which is rotationally connected to the stirring turbine and which is enclosed in the stirring enclosure, and on the other hand, a stator which is placed outside said enclosure, magnetic fields produced by said stator being capable to pass through the wall of the stirring enclosure to cause the rotor to rotate.
The forced recirculation mixer according to the present invention comprises means for the introduction of liquid in a controlled quantity which consist of a liquid piston pump which comprises a pump casing, said pump also comprising at least one single or double acting pump piston which, by the action of a piston actuator cooperating with displacement control means, is capable to move in translation in a pump cylinder to form at least one pump chamber of variable volume in which the vaporizable liquid can be introduced via an inlet valve, and from which said liquid can be expelled to the liquid injection nozzle via a discharge valve.
The forced recirculation mixer according to the present invention comprises a piston actuator which consists of a actuator rotary electric motor secured to the pump casing, said motor being capable to rotate in either direction in order to rotationally drive driving transmission means which are integral in translation with the pump casing and which cooperate with driven transmission means which are integral in translation with the pump piston, said driving transmission means reacting with said casing to longitudinally move in translation said driven transmission means.
The forced recirculation mixer according to the present invention comprises driving transmission means which consist of a worm which rotates a worm wheel which has a wheel thread, the driven transmission means consisting of a piston thread that cooperates with the wheel thread.
The forced recirculation mixer according to the present invention comprises a gas mass flowmeter which measures, directly or indirectly, the mass flow rate of the gas to be mixed circulating in the gas inlet duct and/or the mass flow rate of the homogeneous gas mixture circulating in the mixture draw-off duct.
The forced recirculation mixer according to the present invention comprises means for the introduction of liquid in a controlled quantity which consist of an impulse pump which comprises a single or double acting impulse pump piston which, by the action of a pump solenoid actuator, is capable to move in translation through an impulse pump cylinder with which it forms at least one impulse pump chamber of variable volume into which the vaporizable liquid can be introduced via an impulse pump inlet valve, and from which said liquid can be expelled to the liquid injection nozzle via an impulse pump discharge valve.
The forced recirculation mixer according to the present invention comprises a volume and/or mass flow rate of vaporizable liquid which is sent back to the computer by a vaporizable liquid flowmeter placed upstream or downstream of the controlled quantity liquid introduction means.
The forced recirculation mixer according to the present invention comprises a vaporizable liquid flowmeter which is constituted by a flowmeter piston which can move in a sealed manner in a flowmeter cylinder so as to form, on the one hand, a flowmeter upstream chamber which is directly or indirectly connected to a pressure source and, on the other hand, a flowmeter downstream chamber which is directly or indirectly connected to the liquid injection nozzle, the position of said piston in said cylinder being transmitted to the computer by a position sensor, a flowmeter piston return spring tending to push the flowmeter piston towards the flowmeter upstream chamber.
The forced recirculation mixer according to the present invention comprises a flowmeter upstream chamber which is connectable to the flowmeter downstream chamber by a flowmeter piston return valve.
The forced recirculation mixer according to the present invention includes a flowmeter piston return valve which includes an orientable sealing plate which can be held pressed on a valve orifice by a valve solenoid actuator.
The forced recirculation mixer according to the present invention comprises a nozzle accumulator which is interposed between the means for the introduction of liquid in a controlled quantity and the liquid injection nozzle.
The forced recirculation mixer according to the present invention comprises a nozzle accumulator which comprises a nozzle accumulator piston which, together with an accumulator cylinder, forms an accumulator chamber, said piston being pushed towards said chamber by an accumulator spring, the liquid injection nozzle being integral with said piston and passing through the latter right through in the lengthwise direction thereof.
The description which will follow made with reference to the accompanying drawings and provided by way of non-limiting examples will make it possible to better understand the invention, the characteristics thereof, and the advantages that it is likely to provide:
The forced recirculation mixer 1 according to the present invention, various details of its components, its variants, and its accessories are shown in
As is clear from
It can be seen from
It is to be noted in
It is to be noted that the liquid injection nozzle 9 may be an integral part of the means 10 for the introduction of liquid in a controlled quantity, the latter possibly consisting for example of an electromagnetic, piezoelectric or electro-hydraulic-controlled injector, known per se, or a pump injector whose piston or pump diaphragm is actuated by a solenoid or a piezoelectric battery and whose injected quantity of vaporizable liquid 2 per unit of time is reasonably controllable.
In
As shown in
It is to be noted that, as shown in
As shown in
It can also be seen in
As an alternative embodiment of the forced recirculation mixer 1 according to the invention shown in
In this case, the reversing terminating end 15 through which the gas inlet duct 7 passes may have a hollow hemi-toroidal shape from which said duct 7 emerges.
In
As shown in
It is also to be noted that, as shown in
As can be seen in
In
As an alternative shown in
It is to be noted that according to this particular configuration of the forced recirculation mixer 1 according to the present invention, the wall of the stirring enclosure 5 can be advantageously made of non-magnetic material such as stainless steel, aluminum, or brass.
It will be noted that the displacement control means 44 may, for example, be constituted by an angular or linear, optical or “Hall effect”, absolute or incremental encoder, or be constituted by the step-by-step driving of one or more linear or rotary electric motors, said control means 44 making it possible, in any case, a computer 45 to drive the position and the advancement speed of the pump piston 33 in the pump cylinder 35 and thus, to control the amount of vaporizable liquid 2 introduced into the recirculation loop 6 per unit of time.
It will also be noted that the pump piston 33 may comprise a piston seal 19 made, for example, of elastomer, said seal 19 may be simple, or composite and constituted of an O-ring that cooperates with a ring made of PTFE charged with anti-abrasive and/or anti-friction particles.
It is to be noted in
It will also be noted that the driving transmission means 40 may for example consist of a wheel which is tapped at its center and which is connected to the actuator rotary electric motor 39 by means of a reducer formed by a series of pinions, an epicyclic train, a succession of toothed pulleys and toothed belts, or any other type of reduction gear known to those skilled in the art, said wheel cooperating with a threaded rod which is integral in translation with the pump piston 33 and which forms the driven transmission means 41.
It will also be noted that the driving transmission means 40 and the driven transmission means 41 can be replaced by any other mechanism producing an equivalent or similar effect such as a rack and pinion gear device, or a pulley and cable device.
As shown in
As shown in
Once the mass flow rate of the vaporizable liquid 2 to be introduced into the stirring enclosure 5 is determined, the computer 16 can control the means 10 for the introduction of liquid in a controlled quantity so that it delivers to the liquid injection nozzle 9 the mass flow of vaporizable liquid 2 necessary for the formation of the desired homogeneous gas mixture 4 in the stirring enclosure 5.
In this case, the impulse pump piston 64 may form with the impulse pump cylinder 67 at least one impulse pump chamber 68 of variable volume into which vaporizable liquid 2 may be introduced via an impulse pump inlet valve 69, and from which said liquid 2 may be expelled to the liquid injection nozzle 9 via an impulse pump discharge valve 70.
In
According to this particular configuration of the forced recirculation mixer 1 of the invention, the vaporizable liquid flowmeter 71 may be constituted by a flowmeter piston 72 which can move in a sealed manner in a flowmeter cylinder 73 so as to form a flowmeter upstream chamber 75 which is directly or indirectly connected to a pressure source 77; the latter may be constituted by the fuel pump 53 of an internal combustion engine 51 which in parallel feeds the injectors known per se of said engine 51.
In this case, the flowmeter piston 72 also forms with the flowmeter cylinder 73 a flowmeter downstream chamber 76 which is directly or indirectly connected to the liquid injection nozzle 9.
Still according to this particular configuration of the forced recirculation mixer 1 of the invention, the position of the flowmeter piston 72 in the flowmeter cylinder 73 is transmitted to the computer 45 by a position sensor 74 which may be inductive, capacitive, optical, or of any type known to those skilled in the art, a flowmeter piston return spring 78 tending to push the flowmeter piston 72 toward the flowmeter upstream chamber 75.
As can be seen clearly in
In this case, vaporizable liquid 2 is transferred from the flowmeter upstream chamber 75 to the flowmeter downstream chamber 76, this transfer resulting from the force exerted by the flowmeter piston return spring 78 on the piston flowmeter 72 which has the effect of moving the latter in the direction of the flowmeter upstream chamber 75.
It is to be noted that the flowmeter piston return valve 72 may be of the “normally open” type as shown in
As another variant embodiment of the forced recirculation mixer 1 according to the present invention, it has been shown in
In this case, the nozzle accumulator 80 may comprise a nozzle accumulator piston 81 which, together with an accumulator cylinder 82, forms an accumulator chamber 83, said piston 81 being pushed in the direction of said chamber 83 by an accumulator spring 84, the liquid injection nozzle 9 being integral with said piston 81 and passing right through the latter in the lengthwise direction thereof.
The operation of the forced recirculation mixer 1 according to the present invention is easily understood in view of
To illustrate this operation, let us suppose here that, as shown schematically in
As can be seen in
In addition, and compared to a carburetor or injector placed at the inlet of the compressor 18, the forced recirculation mixer 1 according to the invention prepares a homogeneous gaseous mixture 4 of more precise composition, of greater homogeneity, and potentially reduces the quantity of homogeneous gaseous mixture 4 stored between the inlet of the compressor 18 and the stratification injector 20.
The mixer 1 according to the present invention also ensures permanent mixing of the homogeneous gas mixture 4 even when the internal combustion engine 51 is momentarily stopped, which is desirable, for example, in the context of thermal-electric hybrid applications such as found in automobiles.
As such, the forced recirculation mixer 1 according to the present invention provides a greater freedom in the technical definition of the compressor 18 than a carburetor or injector placed at the inlet of said compressor 18.
The fact remains that a carburetor or injector remains a possible solution for implementing the valve-controlled ignition pre-chamber 21 on any internal combustion engine 51, in particular if said engine is fitted to a mass-produced automobile.
In the context of the particular application of the forced recirculation mixer 1 according to the invention disclosed herein, the homogeneous gas mixture 4 constitutes the pilot charge 55 introduced by the stratification injector 20 in the valve-controlled ignition pre-chamber 21 on each cycle of the internal combustion engine 51.
According to this particular example of the use of the forced recirculation mixer 1 of the invention, the stratification injector 20 and the valve-controlled ignition pre-chamber 21 thus form gas draw-off means 12.
We will assume here that the gas 3 to be mixed is atmospheric air 49 while the vaporizable liquid 2 is gasoline 50 as commonly consumed by automobiles.
Let us also suppose here that the homogeneous gas mixture 4 which feeds the stratification injector 20 must be composed, as a non-limitative example, of fourteen grams of air 49 per gram of gasoline 50, said gas mixture 4 being therefore slightly rich compared to stoichiometry.
Let us consider that in this particular application of the forced recirculation mixer 1 according to the invention, the mass flow of homogeneous gas mixture 4 to be supplied to the stratification injector 20 when the internal combustion engine 51 is idling is one hundred and fifty times lower than the mass flow of said mixture 4 to be supplied to said injector 20 when said engine 51 is operating at full power.
Let us consider here that whatever the operating point of the internal combustion engine 51, the mass proportion of air 49 and gasoline 50 of which the homogeneous gaseous mixture 4 is constituted must not vary.
Let us also assume that the homogeneous gas mixture 4 consisting of air 49 and gasoline 50 is supplied to the stratification injector 20 under a pressure of forty bars.
To achieve this result, we note in
As a non-limiting example of an embodiment of said mixer 1,
In
Thus constituted, the liquid piston pump 32 forms the means 10 for the introduction of liquid in a controlled quantity.
It is to be noted in
To achieve a homogeneous gas mixture 4 in the proportion of fourteen grams of air 49 per gram of gasoline 50 under a pressure of forty bars, the stirring enclosure 5 in which said mixture 4 is produced must be carried at a temperature of at least seventy degrees Celsius.
Said temperature is necessary so that all of the gasoline 50 which forms the homogeneous gas mixture 4 passes to the vapor state and remains in said state, taking into account the saturated vapor pressure of said gasoline 50 at said temperature.
This is why, as shown in
Thus, the thermal control chamber 26 is a heating or cooling means 25 which ensures that gasoline 50, from which the homogeneous gas mixture 4 is formed in part, remains entirely vapor, this despite the pressure of forty bars to which said mixture 4 is subjected.
When the internal combustion engine 51 is idling, the total quantity of homogeneous gaseous mixture 4 introduced each second into the valve-controlled ignition pre-chamber 21 by the stratification injector 20 is very small. As an order of magnitude, said amount may be twenty-two normalized cubic centimeters of air 49 mixed with two point five cubic millimeters of gasoline 50.
Also, to obtain a homogeneous mixture of air 49 and gasoline 50, the homogeneous gas mixture 4 is stirred in the recirculation loop 6 formed by the internal cavity of the stirring enclosure 5.
Let us assume here that the stirring enclosure 5 contains sixty cubic centimeters of homogeneous gaseous mixture 4 subjected to a pressure of forty bars. This quantity of said mixture 4 is that which is supplied each minute by the stratification injector 20 to the valve-controlled ignition pre-chamber 21 in the form of pilot charges 55 when the internal combustion engine 51 is operating at idle.
When the internal combustion engine 51 is idling, the mass flow rate of homogeneous gaseous mixture 4 circulating in the recirculation loop 6 is thus several tens to several hundreds of times greater than the flow rate of said mixture 4 drawn-off from the stirring enclosure 5 by the stratification injector 20 to supply the valve-controlled ignition pre-chamber 21.
The current flow of homogeneous gaseous mixture 4 contained in the stirring enclosure 5 and the stirring of said mixture 4 produced by its incessant displacement in the recirculation loop 6 allows to average the composition of said mixture 4 over a long period of time, and making said mixture 4 highly homogeneous.
The stirring of the homogeneous gas mixture 4 is particularly shown in
It is to be noted in
In
In
It is to be noted in
This particular configuration of the turbine motor 28 avoids the use of a rotating shaft sealing passing through the wall of the stirring enclosure 5 to ensure the rotation drive of the stirring turbine 13, this being advantageous in view of the relatively high pressure of forty bars prevailing in said enclosure 5.
As can be clearly seen in
As can be seen in
The liquid injection nozzle 9 introduces into the air 49 circulating in the gas intake conduit 7 the necessary quantity of vaporizable liquid 2 constituted here by gasoline 50 symbolized by the letter “F”, so that a more or less homogeneous gaseous mixture 4 is formed, containing more or less gasoline 50 in the liquid state, this in the proportion of fourteen grams of air 49 per gram of gasoline 50.
Thus, the air 49 is pre-mixed with the gasoline 50, part of which evaporates in the gas inlet duct 7, and the resulting gas mixture then flows into the stirring enclosure 5.
The premixture of air 49 and gasoline 50 is then set in motion in the recirculation loop 6 by the homogeneous gas mixture 4 already circulating there. Said premixture is then stirred in particular by the stirring turbine 13 and by the stirring blades 22, the gasoline 50 which constitutes said premixture evaporating entirely to form the desired homogeneous gas mixture 4.
It should be noted that if some of the gasoline 50 leaves the gas inlet duct 7 in the liquid state, it will inevitably be deposited on the surface of the blades 17 of the stirring turbine 13, on the inner or outer face of the internal coaxial duct 16, on the inner face of the external coaxial duct 14, or on the surface of the stirring blades 22. Then, the forced circulation of the homogeneous gas mixture 4 in the recirculation loop 6 will dry said surfaces which carry said gasoline 50 in the liquid state, so that said gasoline 50 joins said gas mixture 4 in the vapor state.
As shown in
It is to be noted in
As can be seen in
Thus, when the homogeneous gas mixture 4 is drawn-off from the stirring enclosure 5 by the stratification injector 20, said mixture 4 is perfectly homogeneous, and consists exclusively of air 49 and gasoline 50 in proportion to fourteen grams of air 49 per gram of gasoline 50.
To obtain precisely such a proportion of air 49 and gasoline 50, it is necessary to know the mass flow of air 49 admitted into the stirring enclosure 5, in order to be capable to introduce into said air 49 the right quantity of gasoline 50 via the liquid injection nozzle 9.
For this reason, the forced recirculation mixer 1 of the invention cooperates, according to the embodiment described here to illustrate its operation, with a mass flowmeter of gas 46 which can be depressogenic, pitot tube, ludion, with cup, propeller or turbine, with pallet, ionic, ultrasonic, electromagnetic, Coriolis, Karman tourbillon or vortex effect, with hot wire or film, thermal mass, or in general, of any type known to the skilled person.
Said flowmeter 46 returns the effective mass flow rate of air 49 allowed in the stirring enclosure 5 to the computer 45, which is symbolized in
As shown in
As shown in
As can be clearly seen in
As the worm wheel 43 rotates by the action of the worm 47, it screws or unscrews the female wheel thread 56 around the male piston thread 57, thereby moving the double-acting pump piston 33 translationally in the pump cylinder 35.
It is to be noted in
It is also to be noted in
Finally, it can be noted in
In
It is to be noted, particularly in
Thus, if the worm wheel 43 has thirty teeth, if the pitch of the wheel thread 56 and the piston thread 57 is one millimeter, and taking into account the thirty pulses generated by the “Hall Effect” encoder at each turn of the actuator rotary electric motor 39, a pulse of the “Hall Effect” encoder corresponds to a displacement of the pump piston 33 of approximately one micrometer.
As the ratio between the displacement of pump piston 33 and the amount of gasoline 50 expelled from the corresponding pump chamber 36 is known from computer 45, the latter can precisely control the rotation of the actuator rotary electric motor 39 so as to generate a mass flow of gasoline 50 to be expelled via the liquid injection nozzle 9 worth one fourteenth of the mass flow of air 49 sent back to said computer 45 by the gas mass flowmeter 46.
As can be easily inferred from the above, the forced recirculation mixer 1 according to the present invention makes it possible to produce a homogeneous gas mixture 4 formed here of air 49 and gasoline 50 in proportion to fourteen grams of air 49 per gram of gasoline 50.
For this, the forced recirculation mixer 1 does not require a high-pressure gasoline pump, the pressure of a few bars usually supplied by the gasoline pumps 53 fitted to the most widespread multipoint injection systems in the automotive industry is, for example, sufficient to supply the liquid piston pump 32. Indeed, it is the liquid piston pump 32 itself which is in charge of raising the pressure of the gasoline 50 to more than forty bars necessary for the introduction of said gasoline 50 in the stirring enclosure 5 via the liquid injection nozzle 9.
To achieve the desired result, the forced recirculation mixer 1 according to the invention also does not require a high-precision injector whose injected quantity remains uncertain in all cases, particularly at very low flow rates. It should also be noted that the particular configuration of the forced recirculation mixer 1 does not require atomizing the gasoline 50 in fine droplets to ensure the entire vaporization. In fact, this vaporization can be carried out a posteriori in the recirculation loop 6, without damage to the average content of gasoline 50 of the homogeneous gas mixture 4.
As can be inferred from the figures and from the present description of operation of the forced recirculation mixer 1, the liquid piston pump 32 simultaneously ensures the injection and the measurement of the flow rate of the gasoline 50 introduced into the stirring chamber 5 via the liquid injection nozzle 9. Said liquid piston pump 32 therefore avoids having to use a gasoline flowmeter 50 to form the homogeneous gas mixture 4 in due proportion of air 49 and gasoline 50.
It can be seen that if the diameter of the pump piston 33 is twelve millimeters, this with a worm wheel 43 of thirty teeth, a wheel thread pitch 56 and a piston thread pitch 57 of one millimeter, and with thirty pulses generated by the “Hall effect” encoder with each revolution of the actuator rotary electric motor 39, one pulse of the “Hall effect” encoder corresponds to approximately zero point eight milligrams of gasoline 50 injected into the stirring enclosure 5 via the liquid injection nozzle 9.
If the pitch of the wheel thread 56 is halved, the amount of gasoline 50 injected per pulse of the “Hall effect” encoder is twice as small.
It should be noted that, to the total number of pulses generated by the “Hall effect” encoder over the entire stroke of the pump piston 33, thus corresponds a certain quantity of gasoline 50, determined with great precision.
As a result, the accuracy of the amount of gasoline 50 introduced into the stirring enclosure 5 via the liquid injection nozzle 9 between two pulses of the “Hall effect” encoder is on average very high.
Since the stirring enclosure 5 dilutes said quantity of gasoline 50 in a large quantity of homogeneous gas mixture 4 over a relatively long time, the richness of the homogeneous gas mixture 4 drawn off by the stratification injector 20 is very precise, which favors control in all circumstances of the operation of the valve-controlled ignition pre-chamber 21 according to patent FR 3,061,743.
It is to be noted that since the pump piston 33 is double-acting, its maximum forward speed may, for example if its diameter is twelve millimeters, not exceed three or four millimeters per second to supply the valve-controlled ignition pre-chambers 21 of a supercharged internal combustion engine 51 of two liters of cylinder capacity operating at maximum power.
This millimeter speed makes it possible to equip said piston 33 with a perfectly sealed piston seal 19, the service life of which will be long despite it operates in gasoline 50 which has no particular lubricating properties.
Indeed, the piston seal 19 may for example be composite and include a ring made of PTFE charged with anti-friction particles, said ring being held in contact with the pump cylinder 35. Such a piston seal 19 is particularly suited to the operating conditions which have just been described and can last at least as long as the internal combustion engine 51 of which it cooperates in supplying the valve-controlled ignition pre-chamber 21 with a homogeneous gas mixture 4 via the stratification injector 20.
It is to be noted that according to the exemplary embodiment of the forced recirculation mixer 1 of the invention which has just been described, the computer 45 advantageously compensates for the losses of average flow rate of gasoline 50 during changes in direction of the double-acting piston pump 33 in the pump cylinder 35.
Indeed, at the reversing point of said piston 33, the actuator rotary electric motor 39 must compensate some play such as the one between the worm 47 and the worm wheel 43, or to compensate for the deformation of the piston seal 19 in its groove when changing the direction of the pressure difference to which the seal 19 is subjected.
The computer 45 can make this compensation by measuring the electrical current required by the actuator rotary electric motor 39 to move, such intensity making it possible to detect when the pump piston 33 again faces a pressure of at least forty bars.
The computer 45 can also incorporate data on the necessary compensation at the reversing point of the pump piston 33, which data resulting of bench tests carried out prior to the first use of the forced recirculation mixer 1 according to the invention.
Thus, taking into account the time allocated to the re-loading operation of the pump piston 33, the computer 45 can reconstruct the average flow required to obtain the homogeneous gas mixture 4 according to the desired air ratio 49 to gasoline 50, bearing in mind that the richness temporary change as seen by the stratification injector 20 is negligible provided the current large amount of homogeneous gas mixture 4 contained in the stirring enclosure 5.
In
According to the example embodiment of the forced recirculation mixer 1 of the invention shown in
It will also be assumed here that the gas 3 to be mixed is atmospheric air 49 while the vaporizable liquid 2 is gasoline 50 as commonly consumed by automobiles.
The impulse pump piston 64 forms, together with the impulse pump cylinder 67, an impulse pump chamber 68 of variable volume into which the gasoline 50 can be introduced via an impulse pump inlet valve 69, and from which said gasoline 50 can be expelled to the liquid injection nozzle 9 via an impulse pump outlet valve 70.
It is to be noted that the impulse pump discharge valve 70 may be highly calibrated—to several bars—so that if the pressure which prevails in the stirring enclosure 5 is lower than that which prevails in the gasoline circuit 50 located upstream of the impulse pump 63, the stirring enclosure 5 does not fill up with gasoline 50 in an undesirable manner.
To inject gasoline 50 into the stirring enclosure 5, the computer 45 supplies the solenoid coil 95 of the pump solenoid actuator 65 with electric current. This has the effect of pushing back the impulse pump piston 64 in the direction of the impulse pump chamber 68, said piston 64 expelling the corresponding quantity of gasoline 50 out of said chamber 68 via the impulse pump discharge valve 70 and the liquid injection nozzle 9.
This done, the computer 45 stops supplying the solenoid coil 95 with electric current so that a pump piston return spring 66 returns the impulse pump piston 64 to bottom dead center and the impulse pump chamber 68 again draws in gasoline 50 via its impulse pump inlet valve 69.
It is to be noted that the pump piston return spring 66 is not necessary if the supply pressure of gasoline 50 which prevails upstream of the impulse pump inlet valve 69 is sufficient to push the impulse pump piston 64 back to bottom dead center within the allotted time.
The nozzle accumulator 80 makes it possible to provide a liquid injection nozzle 9 leaving only a small section to the passage of gasoline 50, which favors a fine atomization of said gasoline 50 at the outlet of said nozzle 9 in the stirring enclosure 5.
The nozzle accumulator 80 also makes it possible the pressure peaks occurring at the outlet of the impulse pump discharge valve 70 to be clipped, thus avoiding the over-sizing of the solenoid coil 95 so as to counter these peaks.
In addition, the nozzle accumulator 80 reduces the range of variations of the gasoline flow rate 50 vaporized into the stirring enclosure 5 by the liquid injection nozzle 9 which conducts to a better homogeneity of the homogeneous gas mixture 4 formed in said enclosure 5.
According to the non-limitative example shown in
In
It can easily be inferred from the above that the gasoline flow rate 50 injected into the stirring enclosure 5 by the impulse pump 63 is the product of the cylinder capacity of said pump 63 by its volumetric efficiency by its actuation frequency.
By way of example, if the cylinder capacity of said pump 63 is thirteen cubic millimeters, if the volumetric efficiency of said pump 63 is seventy percent, and its actuation frequency is thirty Hertz, then, the flow rate of said pump 63 is two hundred and seventy-three cubic millimeters per second.
For the computer 45 to adjust the effective flow rate of the impulse pump 63 necessary for the formation in the stirring enclosure 5 of the homogeneous gas mixture 4 according to the desired air 49 to gasoline 50 ratio, as can be seen in
Thanks to the vaporizable liquid flowmeter 71, the computer implements a software control loop of the “PID controller” type, known per se.
Indeed, the gas mass flowmeter 46 sends back to the computer 45 the effective mass flow of air 49 entering the stirring enclosure 5, of which naturally results the setpoint of the flow of gasoline 50 to be introduced into said enclosure 5 by the impulse pump 63 taking into account the desired air 49 to gasoline 50 ratio.
The flow rate of the gasoline 50 thus forms the value set by the PID controller, said flow rate may oscillate more or less around the set value assigned to it provided that the effective value of said flow rate is close to that set value when averaged over a few seconds.
Indeed, the forced circulation by the stirring turbine 13 of the homogeneous gaseous mixture 4 in the stirring enclosure 5 homogenizes said mixture 4 despite variations in the flow rate of gasoline 50 around the set value.
To regulate up or down the flow rate of gasoline 50, the computer 45 can modulate the frequency and/or the activation power of the pump solenoid actuator 65 of the impulse pump 63.
According to the example of the non-limitative embodiment of the forced recirculation mixer 1 of the invention shown in
It is noted, particularly in
The flowmeter piston sealed extenders 101 ensure that for the same displacement of the flowmeter piston 72, the volume of gasoline 50 admitted or discharged by the flowmeter upstream chamber 75 is identical to that simultaneously admitted or discharged by the flowmeter downstream chamber 76. Thus, the flow rate of gasoline 50 delivered by the gasoline pump 53 is in no way disturbed by the back-and-forth movements of the flowmeter piston 72 in the flowmeter cylinder 73, regardless of the speed of said back-and-forth movements.
The position of the flowmeter piston 72 in the flowmeter cylinder 73 is transmitted to the computer 45 by a position sensor 74 which, in this case, is an absolute linear encoder as marketed by the “Posic” company.
The encoder reads a target strip 100 which is carried by a support-strip guided slider 97, which can be moved in longitudinal translation in a slider guide rail 98 in which it is accommodated with small play, on the one hand, and in the extension of the flowmeter piston 72, on the other hand.
It is to be noted that the support-strip guided slider 97 is secured in translation to the flowmeter piston 72 by a coupling magnet 99, the latter being permanently attracted by the flowmeter piston sealed extender 101 which is positioned on the side of the target strip 100.
In
One can easily infer from the diagram of
In fact, to determine the mass flow of gasoline 50 introduced into the stirring enclosure 5 by the impulse pump 63, the computer 45, on the one hand and via the position sensor 74, retrieves the distance traveled per unit of time by the flowmeter piston 72, and, on the other hand, by means of a temperature sensor 103 placed at the flowmeter downstream chamber 76, the temperature of said gasoline 50.
For example, if the effective section of the flowmeter piston 72 is one hundred and forty square millimeters, when the latter moves one millimeter per second, the volume flow rate of gasoline 50 introduced into the stirring enclosure 5 by the impulse pump 63 is one hundred and forty cubic millimeters per second.
To calculate the mass flow of gasoline 50 introduced into the stirring enclosure 5, the density at twenty degrees Celsius and the thermal expansion coefficient of said gasoline 50 being known because they are entered by the computer (not shown) of the internal combustion engine 51, the computer 45 only has to multiply the density of said gasoline 50 by its volume flow rate.
For greater precision, a pressure sensor 102 may optionally be provided at the flowmeter downstream chamber 76, to allow the computer 45 to include the compressibility of the gasoline 50 into its density calculation of said gasoline. 50.
When the flowmeter piston 72 reaches the end of the reading stroke, that is to say when the volume of the flowmeter downstream chamber 76 reaches its predetermined minimum value, the flowmeter piston return valve 72 opens and connects said downstream chamber 76 with the flowmeter upstream chamber 75, which has the effect of transferring gasoline 50 contained in the flowmeter upstream chamber 75 into the flowmeter downstream chamber 76.
This gasoline transfer 50 results from the force exerted by the flowmeter piston return spring 78 on the flowmeter piston 72, said force having the effect of moving the latter towards the flowmeter upstream chamber 75.
During said transfer of gasoline 50, which may last about 100 milliseconds, the volume flow measurement of gasoline 50 is temporarily interrupted. However, the total measurement error is very small as the computer 45 can reconstitute the flow rate of gasoline 50 during the interruption of the measurement by averaging the flow rate of gasoline 50 recorded just before the opening of the flowmeter piston return valve 72 and that recorded immediately after the closing of said valve 72.
It should be noted that the return of the flowmeter piston 72 described above rarely occurs, for example every 10 minutes when the internal combustion engine 51 is idling, and every four seconds when said engine 51 is operating at full power.
It is to be noted that the flowmeter piston return valve 72 may be of the “normally open” type as shown in
In
In
For example, the compressor outlet leak-proof check valve 90 is used to hold the stirring enclosure 5 under pressure when the internal combustion engine 51 is shut down for a time ranging from a few seconds to a few minutes, said valve 90 being useful when the discharge valves of compressor 18 are not perfectly sealed.
There is also the canister discharge solenoid valve 91 which makes it possible for the stirring enclosure 5 to be gradually depressurized when the internal combustion engine 51 is shut down and cools down. When said solenoid valve 91 opens, the gasoline 50 in the vapor state which forms the homogeneous gaseous mixture 4 contained in said enclosure 5 is transferred to a canister 92 known per se, such canister 92 equipping the majority of modern cars.
It will be noted that the exemplary embodiments of the forced recirculation mixer 1 according to the present invention which have just been described are non-limiting.
In fact, the forced recirculation mixer 1 according to the invention can be applied to fields other than that of internal combustion engines, such as chemistry, industrial processes or all devices in any field whatsoever which require the production in situ of a mixture which is homogeneous and/or precisely dosed consisting of at least one gas and at least one liquid.
The possibilities of the forced recirculation mixer 1 according to the present invention are not limited to the applications which have just been described and it must also be understood that the above description has only been provided by way of example and that it in no way limits the field of said invention, from which one would not depart by replacing the details of execution described by any other equivalent.
| Number | Name | Date | Kind |
|---|---|---|---|
| 4353848 | Carsten | Oct 1982 | A |
| 5992397 | Hideaki | Nov 1999 | A |
| 20100000502 | Hassan | Jan 2010 | A1 |
| Number | Date | Country |
|---|---|---|
| 102182587 | Sep 2011 | CN |
| 3 061 743 | Aug 2019 | FR |
| Number | Date | Country | |
|---|---|---|---|
| 20210340937 A1 | Nov 2021 | US |
| Number | Date | Country | |
|---|---|---|---|
| 63017087 | Apr 2020 | US |
