• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The present invention relates to an internal combustion engine with a compression ratio of between 13.5 and 16.5 and to direct injection with compression ignition comprising a combustion chamber (34) delimited on one side by the upper face (44). a piston (16) having a stud (48) disposed at the center of a concave bowl (46) with at least two mixing zones (Z1, Z2), injection means comprising at least one injector (30) projecting fuel according to at least two plies (36, 38) of fuel jets of different lap angles (A1, A2). According to the invention, the fuel injector comprises two rows of injection orifices (33a, 33b) placed one above the other and the number of orifices of each row (Ninf, Nsup) is greater or equal than -4.Ns + 14 and smaller or equal than -4.Ns + 16 for the lower water table or -4.Ns + 18 for the upper water table where Ns is the number of swirls of this engine with a number of swirls is less than 1.5.
    公开号:FR3020401A1
    申请号:FR1453660
    申请日:2014-04-24
    公开日:2015-10-30
    发明作者:Lionel Martinez；Stephane Richard；Olivier Laget
    申请人:IFP Energies Nouvelles IFPEN；
    IPC主号:
    专利说明:

    [0001] The present invention relates to a direct injection internal combustion engine, in particular to a compression ignition engine, and to a method for controlling the injection of fuel into such an engine.
    [0002] It relates more particularly to an engine used in the aeronautical or road field or in the field of stationary installations, such as a generator. This type of engine generally comprises at least one cylinder, a piston comprising a pin disposed in a concave bowl and sliding in this cylinder in a reciprocating rectilinear motion, means for admitting an oxidizer, means for exhausting burnt gases , a combustion chamber, and injection means for injecting a fuel into the combustion chamber.
    [0003] As is generally admitted, during the design of an engine, the constraints of performance, pollutant emissions and mechanical strength of the combustion chamber are becoming stronger while the means to satisfy them are opposite.
    [0004] Thus the increase in performance generally leads to an increase in pollutant emissions and higher mechanical stresses. It is necessary to overcome these constraints so as to ensure a limited emission of pollutants and satisfactory mechanical strength over the entire operating range of the engine and in particular at very high load. In particular for pollutant emissions the use of all the oxidant present in the combustion chamber, for example an oxidizer comprising ambient pressure air, supercharged air, or a mixture of air (supercharged or not) ) and recirculated flue gas is of great importance.
    [0005] Indeed, it is necessary that the fuel mixture (oxidizer / fuel) in the combustion chamber is as homogeneous as possible.
    [0006] In practice, the fuel remains confined in the bowl and can not mix with the oxidant located in particular in the flush, that is to say in the volume located in the upper part of the combustion chamber defined by the wall of the cylinder and the face of the bolt opposite the piston. This has the disadvantage of creating areas of high richness in the combustion chamber generating a high production of soot, carbon monoxide (CO) and unburned hydrocarbons (HC) during the combustion of this fuel mixture.
    [0007] In addition, to return to the problem of mechanical strength, the heat load is concentrated on the reentrant of the piston, that is to say the collar or the bowl diameter restriction which marks the transition between the piston bowl and the upper zone encompassing hunting, which can be limiting in terms of mechanical strength at very high loads.
    [0008] To overcome these disadvantages, and as is better described in the French patent application No. 13 60426 of the applicant, it is intended to use an internal combustion engine comprising fuel injection means with jets according to at least two web angles and a piston having a bowl provided with a nipple with two volumes of combustion zones and internal aerodynamics substantially improving the quality of combustion. This makes it possible to use a larger amount of oxidant compared to traditional engines and to distribute the heat load over a larger area of the combustion chamber.
    [0009] In this type of engine, the mixture between the fuel injected and the oxidizer, such as air at ambient pressure or supercharged air or a mixture of air (supercharged or not) with exhaust gases Recirculated, admitted into the combustion chamber is done in two stages.
    [0010] Firstly during the fuel injection, the oxidant, located on the periphery of the fuel jet, is driven by the same jet. A small-scale mixture resulting from the turbulence generated by this entrainment then occurs.
    [0011] In order to improve this fuel / oxidant mixture, a swirling motion of the oxidant, called swirl, is used in a second step, which "brews" the unmixed fuel on a large scale. This swirl can be seen as a rotational movement of the oxidizer around an axis substantially parallel or coincident with that of the combustion chamber. This swirl can be obtained by a particular admission of the oxidant, such as by a specific geometry of the intake ducts. In this configuration, however, it should be noted that while the small scale mixture made in the gaseous spray is very fast, the large-scale mixing associated with the swirling movement is slower. The performance of the engine, its fuel consumption or the emissions of pollutants such as soot, carbon monoxide or unburned hydrocarbons, are very dependent on the ability to quickly mix the fuel with the accepted oxidizer. A work of optimization of the injection system and the level of swirl is thus generally realized in order to optimize the performances of the engine. One of the solutions consists in using a swirl rate, referred to as Ns, which is relatively high, of the order of 2 to 3, this ratio being equal to the ratio between the speed of rotation of the swirling motion of the oxidizer and that of the crankshaft. A disadvantage of this solution is that on certain operating points of the engine and more particularly when the fuel injection pressure is low, or when a large quantity of fuel is injected, the fuel jets can be deviated circumferentially. in an excessive way, resulting in an interaction, or even a superposition between the different jets. This phenomenon can significantly increase the emissions of soot and unburned hydrocarbons, while degrading the combustion efficiency and thus the power and consumption.
    [0012] The present invention proposes to overcome the drawbacks mentioned above by means of a process which makes it possible to obtain a better mixture between the oxidant (gaseous fluid) and the fuel injected while allowing the use of a system for injecting fuel at at least two ply angles and a piston whose profile allows the combustion chamber to have at least two combustion zones. For this purpose, the invention relates to a direct injection internal combustion engine with compression ignition comprising at least one cylinder, a cylinder head carrying fuel injection means, a piston sliding in this cylinder, a combustion chamber defined on one side by the upper face of the piston having a pin rising in the direction of the cylinder head and disposed in the center of a concave bowl with at least two mixing zones, said injection means comprising at least one injector projecting fuel according to at least two layers of fuel jets having different angles of lap, a lower layer of jet axis C1 for the zone and an upper layer of jet axis C2 for the zone, characterized in that the fuel injector comprises at least two rows of injection ports placed one above the other and that number of orifices of each row is greater than or equal to -4.Ns + 14 and smaller or equal than - 4.Ns + 16 for the bottom row or -4.Ns + 18 for the top row, where Ns is the swirl rate of that engine. The minimum compression ratio may be around 13.5 and the maximum compression ratio may be around 16.5. The number of swirls may be preferably less than 1.5 and even more preferably of the order of 1.
    [0013] The orifices of the fuel jets of a fuel ply have an angular phase shift with the fuel jet orifices of the other fuel ply.
    [0014] The fuel jet plies comprise a lap angle different from each other.
    [0015] The invention also relates to a fuel injection method for a compression-ignition direct injection internal combustion engine comprising at least one cylinder, a cylinder head carrying fuel injection means, a piston sliding in this cylinder, a combustion chamber bounded on one side by the upper face of the piston having a pin rising in the direction of the cylinder head and disposed in the center of a concave bowl, said method of injecting the fuel in at least two layers of fuel jets different web angles, a lower sheet of jet axis Cl and an upper layer of jet axis C2, characterized in that it consists in injecting the fuel by two rows of injection ports placed on the one on top of the other and that number of orifices in each row is greater than or equal to -4.Ns + 14 and smaller or equal than -4.Ns + 16 for the lower table or -4.Ns +18 for the tablecloth where Ns is the number of swirls of this engine The other features and advantages of the invention will now appear on reading the description which will follow, given by way of illustration and not limitation, and to which are appended: Figure 1 which shows an internal combustion engine according to the invention; - Figure 2 which is a partial view on a large scale of a half-section of the profile of the piston bowl of the engine of Figure 1; - Figure 3 which is a cross-sectional local sectional view of the bowl during the initial fuel injection phase; - Figures 3A and 3B are sectional views respectively along lines AA and BB of Figure 3; - Figure 4 which is another view in transverse local section of the bowl during the final phase of fuel injection; - Figures 4A and 4B are sectional views respectively along lines AA and BB of Figure 4; - Figure 5 which is a variant of Figure 3 with a cross-sectional local sectional view of the bowl during the initial phase of fuel injection; - Figure 5A which is a sectional view along the line AA of Figure 5; FIG. 6 which is another cross-sectional view of the bowl (of the variant shown in FIG. 5) during the fuel injection terminal phase and FIG. 6A which is a sectional view along the line AA of FIG. Figure 6. - Figure 7 which is a graph showing the correlation of the number of holes with the number of swirl Ns for each of the two layers.
    [0016] Referring to FIG. 1, an internal combustion engine with a low compression ratio preferably between 13.5 and 16.5, with direct injection with compression ignition, comprises at least one cylinder 10, a cylinder head 12 closing the cylinder in upper part, fuel injection means 14 carried by the cylinder head and a piston 16 of axis XX 'sliding in the cylinder in a reciprocating rectilinear motion. By fuel, it is understood a liquid fuel, such as diesel, kerosene or any other fuel having the physico-chemical characteristics for the operation of a compression ignition type engine including a direct injection system of the fuel. This engine also comprises a flue exhaust means 18 with at least one exhaust pipe 20 whose opening can be controlled by any means, such as for example an exhaust valve 22 and an intake means 24. an oxidizer with at least one intake pipe 26 whose opening can be controlled by any means, such as an intake valve 28. The intake means are shaped to admit the oxidant with a given swirl rate preferably less than 1.5. For this, the intake means may comprise at least one valve means and the motor may comprise at least one control means for actuating the valve means so as to obtain the determined swirl rate, preferably less than 1.5 . These admission means may also comprise a specific geometry of the intake manifold 26.
    [0017] The injection means comprise at least one fuel injector 30, preferably disposed in the axis XX 'of the piston whose nose 32 comprises a plurality of orifices 33 through which the fuel is sprayed and projected towards the chamber combustion engine 34.
    [0018] It is from these injection means that the projected fuel forms at least two plies of fuel jets, here two plies 36 and 38 of fuel jets 40 and 42, which, in the example shown, have an axis general confused with that of the piston 16 while being located axially one above the other. More precisely, the ply 36, which is located closest to the piston 16, is hereinafter referred to as the lower ply, while the ply 38 placed furthest from this plunger is called the upper ply. As can be seen in FIG. 1, these two plies form plane angles A1 and A2 that are different from one another. By ply angle, it is understood the vertex angle that forms the cone from the injector and whose fictitious peripheral wall 20 passes through all the axes C1 or C2 of the fuel jets 40 or 42. Advantageously, the angle Al web of the low web is preferably between 40 ° and 105 °, while the ribbon angle A2 of the upper web is preferably between 155 ° and 180 °. For reasons of simplification in the rest of the description, the angle α1 corresponds to A1 / 2 while the angle a2 corresponds to A2 / 2 (see FIG. 2). Preferably, the difference between the angle A1 and the angle A2 is greater than or equal to 50 °. This thus makes it possible to limit the overlaps of fuel jets between the two sheets and therefore the formation of pollutants, such as soot, as well as any interaction between the sheets during injection and large-scale swirling processes. .
    [0019] This configuration of the injector also makes it possible to position the orifices of the two plies above each other, although in general it may be preferred to angularly shift them to ensure the absence of interaction between the jets, as this is better described in the French patent application No. 14/52119 of the applicant. Of course, it can be expected that the injection means are not arranged in the axis XX ', but in this case, the general axis of the fuel jet layers from the fuel injector is at least substantially parallel to this axis XX '. Similarly, it may be provided that each web is carried by a separate injector (single-web injector) with dedicated targeting in separate areas of the combustion chamber.
    [0020] The combustion chamber 34 is delimited by the internal face of the cylinder head 12 opposite the piston, the circular inner wall of the cylinder 10 and the upper face 44 of the piston 16. This upper face of the piston comprises a concave bowl 46, here of axis coincident with that of the cylinder, whose concavity is turned towards the cylinder head and which houses a stud 48 located substantially in the center of the bowl, which rises towards the cylinder head 12, being preferably coaxial with the axis of the sheets Of course, it can be provided that the axis of the bowl is not coaxial with that of the cylinder but the essential lies in the arrangement according to which the axis of the sheet of fuel jets. , the axis of the stud and the axis of the bowl are preferably merged. Referring additionally to Figure 2, the stud 48, of generally frustoconical shape, has an apex 50 preferably rounded, continuing, deviating symmetrically from the axis XX 'towards the outside of the piston 16, by a substantially rectilinear inclined surface 52 continuing with an inclined flank 54 to reach a bottom 56 of the bowl.
    [0021] Of course and without departing from the scope of the invention, the inclined surface 52 may be non-existent (zero length) and the inclined side 54 then connects the top of the stud to the bottom of the bowl.
    [0022] In the example of FIG. 2, the bottom of this bowl is rounded with a concave curved surface 58 in the form of an arc of radius R1, referred to as the inner rounded surface, connected to the bottom of the inclined sidewall 54 and another concave rounded surface 60 in an arc of radius R2, said outer rounded surface, connected by one of its ends to the lower end of the inner rounded surface at a point M and the other of its ends to a side wall 62, here substantially vertical, at one point N. The two rounded surfaces 58 and 60 thus define the lower part of a toric volume, here a torus of substantially cylindrical section 64 and center B whose role will be explained in the following description.
    [0023] The lateral wall 62 continues, always deviating from the axis XX ', by a rounded convex surface 66 in a circular arc of radius R3, called a reentrant, ending in an inclined plane 68 connected to a concave inflexion surface. 69 This flat surface is continued by an outer convex surface 72 in an arc of radius R5 which arrives at a flat surface 74 extending to the vicinity of the wall of the cylinder. The combustion chamber thus comprises two distinct zones Z1 and Z2 in which mixing takes place between the oxidant they contain (air - supercharged or not - or mixture of air and recirculated flue gases) and the fuel from the combustion chamber. injector as well as the combustion of the fuel mixture thus formed. The zone Z1, delimited by the stud 48, the torus 64 of the bottom of the bowl, the wall 62 and the rounded convex surface 66, forms the lower zone of the combustion chamber which is associated with the lower layer 36 of fuel jets. C1 axis. Z2 zone, demarcated by the inclined plane 68, the concave surface 69, the substantially planar surface 70, the convex surface 72, the flat surface 74, the peripheral inner wall of the cylinder and the cylinder head 12, constitutes the upper zone of this chamber. which is associated with the upper layer 38 of C2 axis fuel jets. In this configuration, the bowl comprises, for a position of the piston close to top dead center: - an outer diameter of FD bowl bottom with a radius considered between the axis XX 'and the lowest point M of the bowl, c' that is to say at the intersection between the ray surfaces R1 and R2, - a diameter of the bowl opening BD with a radius considered near the bottom of the bowl and corresponding to a distance taken between the axis XX 'and the furthest point of the external concave surface 60, - a neck diameter GD with a radius which corresponds to the distance between the axis XX 'and the vertical wall 62 which defines the outlet section of this bowl, - a diameter d high injection Dl with a radius which corresponds to the distance between the axis XX 'and the beginning of the inflection surface 69 at the point P between the inclined plane 68 and the convex surface 66 delimiting a length L6 of the jets 38 between the T2 origin of the C2 axis of the jets on the axis of the nose of the injector and the point P and which responds the formula 'Dl isin (a2), - a developed length of the diametrical half-cut Cb of the bowl, constituted by the length from the intersection of the top of the nipple with the axis XX' to the wall of the cylinder; a height H of stud between the bottom of the bowl at the point M to the top of the stud, - a height L of the bowl between the bottom of the bowl at the point M to the plane surface 74, a junction height L3, which corresponds to the extent of the lateral wall 62, considered between the end of the outer rounded surface 60 at the point N and the beginning of the outer rounded surface 66, a height L4 considered between the point P and the point M, a tilt angle a3 with respect to a vertical for the inclined sidewall 54, a tilt angle a4 formed by the main axis C1 of the fuel jets of the lower sheet 36 impacting the torus with the tangent at the point d F impact by delimiting a length L5 of the jets 40 between the origin Ti of the axis C1 of the jets on the axis of the nose of the injector and the point F. This length L5 corresponds to the formula 1D2 / sin (al) with ID2 which corresponds to a low injection diameter with a radius which corresponds to the distance between the axis XX 'and the point F, - an angle of inclination a5 considered at the tangency of the outer rounded surface 60 with the side wall 62 at the point N, - an angle of inclination a6 with respect to the horizontal and the tangent to the substantially plane wall 70 an angle of inclination a7 with respect to the horizontal and the inclined plane 68 at the intersection point P. All these parameters are appreciated for a position of the piston 16 in the vicinity of the top dead center which corresponds to a distance D considered between the point M and the origin T2 of the axis C2 of the jets 42.
    [0024] More precisely, this distance D is equal to the sum of the height L4 and the height C, height C which corresponds to the axial height between the origin T2 and the point P. This height corresponds to the formula 'Dl itan (a2 ). Thus, the dimensional and angular parameters of this bowl satisfy at least one of the following conditions: the angle a4 is greater than 80 °. This amounts to passing more than half of the fuel jet between the center B of the torus 64 and the pin and more precisely the lower part at the point M and thus to ensure an aerodynamic movement in the torus going back up the cylinder, - the angle a5 must be positive and less than 90 °. Preferably, it must be of the order of 30 ° to 40 ° to direct the fuel jets 40 of the lower sheet 36 to the volume of oxidizer Si to use the oxidizer of this zone while limiting the rise of this fuel to the upper layer 38, the volume Si of oxidant situated between the fuel jets 40 of the lower layer is minimized, again with a view to optimizing the use of the oxidizer in the chamber, the position of the top of the stud 48 is as close as possible to the nose 32 of the injector 30 in order to limit the volume of oxidizer under the injector which will not be impacted by the fuel jets, which again amounts to minimizing the volume Si. Thus the ratio H / L is greater than 40% and preferably greater than 60%, - the angle a3 is substantially equal to or greater than the angle α1 of the lower layer (-10 ° <α3-α1 <10 °). Thus, the general axis of the jets of the lower layer tangents the flank 54 of the stud. The fuel jets 40 of the lower ply 36 can thus interact with the rounded surface 58 by vaporizing completely before impacting the piston, the volume of oxidizer S 2 between the two plies is non-zero since the interaction between the plies is harmful. for pollutants. The volume S2 must nevertheless be minimized. To do this, the length of junction L3 between the torus and the reentrant 66 (convex rounded surface of radius R3) must be such that L3 / (2 * length of R2) <1 or (L3 / length of R2 <2) so to ensure that the volume of oxidizer S2 available between the upper and lower plies 38 and 38 is small relative to the volume of fuel generated by the jets of the lower ply, - the second combustion zone Z2 located in the upper part of the plunger which starts from the reentrant 66 is intended for the fuel jets 42 of the upper sheet 38, - the combustion volume of the zone Z2 is at least equal to one tenth of the total volume of the bowl, - the so-called hunting zone is formed by the inclined plane 68, the concave surface 69, the flat surface 70, the convex surface 72 and the flat surface 74. the angle a6 is between 100 and 75 °, which makes it possible to burst the fuel jets 42 to create an aerodynamic motion above the piston and additionally to a use the oxidizer in the hunting area. This aerodynamics allows a better fuel / oxidant mixture above the piston, in particular during the expansion and thus promote the oxidation of the flue gases, - to promote the distribution of fuel from the jets 42 in the flush, a guide surface 68 is provided between the reentrant 66 and the surface 70. This guide surface may be rounded in extension of the reentrant or substantially flat. This guiding surface serves to concentrate the fuel jets 42 and to guide them towards the convex surface 72. Thus this guiding surface has an angle a7 at the point of intersection P whose deviation from the ply angle α2 is less than 45 °, the location of the inflection surface 69 is such that the distances L5 and L6 are approximately of the same order (0.5 <L5 / L6 <2). Thus, advantageously the fuel jets will substantially impact at the same time the piston in the torus and the inflection zone respectively. the diameter D1 must be such that ID1 / GD> 1 and 'D1 <(GD + (Cb-GD) * 2/3). This allows the fuel jets 42 to optimize the aerodynamics above the piston. In addition, the ratio BD / L is less than 6, preferably less than 4, the ratio R2 / R1 is less than 1, preferably less than 0.6, the ratio FD / BD is less than 1, the ratio Cb / BD ratio is less than 2 to keep a complete vaporization of the fuel and to avoid the wetting of the wall of the cylinder, - the ratio GD / BD is between 0.7 and 1 for the toroid aerodynamics and the rise of the fuel jets the H / L ratio is greater than 40%, preferably greater than 60% to minimize the volume of oxidant between the nozzle nose and the nipple; the L5 / L6 ratio is between 0.5 and 2; the impact of the two sheets at the same time, A1 is between 40 ° and 130 ° with al = A1 / 2, A2 is between 130 ° and 180 ° with a2 = A2 / 2, 25-a3 is substantially equal to al, - a4 is greater than 80 °, - a5 is between 0 ° and 90 °, preferably substantially 30 ° to 40 °, - the angle a6 is co Between 15 ° and 75 °, a7-a2 is less than 45; the ratio ID1 / GD is greater than 1; and D1 is less than (GD-F (Cb-GD) 2/3).
    [0025] Thus, thanks to this setting of the bowl, the fuel jets of the lower sheet 36 directly target the torus 64 and do not directly impact the reentrant 66.
    [0026] As a result, the combustion of the fuel / lower oxidant mixture takes place essentially in the volume of the torus while the combustion of the fuel / higher oxidant mixture takes place essentially in the flush and above the piston. In addition, the interaction of the jets of the upper layer with the jets of the lower layer is limited, which makes it possible to homogenize the oxidant / fuel mixture while complying with high-load mechanical strength constraints. Referring now to FIG. 3 in conjunction with FIG. 1 which illustrates an example of fuel injection into the combustion chamber 34. As already mentioned, the injector 30 carries at its nose 32 injection 33 from which radially leave the fuel jets (see Figure 1). These orifices consist of at least two series of fuel injection radial apertures 33a and 33b placed substantially parallel to each other. The orifices are arranged circumferentially on the nose and the series are placed one above the other. One of the series comprises orifices 33a through which the fuel is injected by forming the lower layer of jets 36 of axis C1 for the mixing zone Z1. The other of the series comprises orifices 33b for fuel injection forming the upper layer 38 of jet C2 axis for the mixing zone Z2. In this configuration, the radial injection of the fuel jets is carried out in a radial direction from the injector away from the injector towards the walls of the combustion chamber and which corresponds to the axes C1 and C2. Of course and without departing from the scope of the invention, the diameters of the orifices 33a and 33b may be different. By way of example, the diameter of the orifices 33a may be greater than the diameter of the orifices 33b. As the injection pressure is identical in the region of the nose of the injector, this has the effect of producing two layers of fuel jets with different flow rates. The fact that the two combustion zones Z1 and Z2 operate independently, also makes it possible to choose the number of orifices of the two sheets independently. Knowing that the swirl rate "Ns" in the zone Z1 is always greater than the swirl rate "Ns" in the zone Z2, it will be possible to use a higher number of holes for the upper layer 38 because the jet jet interactions of the same sheet due to the swirling flow of the gaseous fluid will be weaker.
    [0027] Thus, it will seek to multiply the number of orifices N of different layers to promote the speed of mixing and combustion. For the lower layer, it is proposed to correlate the swirl ratio "Ns" in the zone Z1 and the number of orifices of the jets of this "Ninf" layer such as -4.Ns + 14 Ninf -4.Ns + 16 .
    [0028] Concerning the upper layer 38, the correlation depends on the number of orifices of the fuel jets of this "Nsup" layer with -4.Ns + 14Nsug-4.Ns + 18. Given that the swirl rate in zone Z1 is always greater than the swirl rate in zone Z2, it will be possible to use a higher number of injection orifices for the upper layer because the jet jet interactions of this zone water table due to the swirling flow of the gaseous fluid will be lower. In addition, the fact that the two combustion zones Z1, Z2 operate independently, also makes it possible to choose the number of injection orifices 25 of the two sheets independently. The mixture between the fuel and the oxidant is then mainly achieved by the entrainment of the oxidant by the fuel jets, the contribution related to the vortex swirl remaining weak and being retained only to complete the mixing process by stirring. large scale during the relaxation of the piston.
    [0029] Referring now additionally to Figure 3 which illustrates, without limitation, an injector with 24 injection ports with 12 orifices 33a and 12 orifices 33b, the jets 40 of the ply 36 are regularly distributed circumferentially each being separated from each other. an angle α substantially equal to 300 with respect to their axis C1 and the jets 42 of the ply 38 are also distributed regularly circumferentially each being separated by an angle p substantially equal to 30 ° with respect to their axis C2. In addition, the apertures 33a of the lower ply and the orifices 33b of the upper ply here have an angular phase shift, denoted b2, which is here substantially equal to the half-angle between two jets of the same ply. This angular phase shift has the advantage of reducing the risk of interaction between the two layers when the fuel from the lower layer rises from the bottom of the bowl to the upper part of the Z1 zone in the terminal injection phase. A particularity of this injection system lies in the fact that it uses a large number of holes and not necessarily equal on each of the plies with a low swirl number, ideally less than 1.5, in order to achieve the mixing between the fuel and the gaseous fluid in the fastest possible manner and this mainly during the injection process. This mixture is then mainly achieved by the entrainment of the gaseous oxidant by the fuel jets, the swirl swirling contribution remaining low and being retained only to complete the mixing process by a large-scale stirring at the same time. the relaxation of the piston. Thus, during the injection of the fuel, the oxidant is admitted into the combustion chamber 34 in a swirling motion S with a swirl ratio preferably less than 1.5. The fuel jets are here, without being restrictive, 24 in number being distributed here equally between the two plies (12 jets for the lower ply 30 and 12 jets for the upper ply) and the angle b2 is 15 °.
    [0030] The fuel jets 40 of the lower layer are directed towards the bottom of the bowl 46 in the zone Z1 (FIG. 3A-section along the line AA of FIG. 3) while the jets 42 of the upper layer are oriented towards the top of the bowl in zone Z2 (FIG. 3B-section along line BB of FIG. 3).
    [0031] During the final phase of injection, it can be seen that, with a moderate number of swirls Ns, ideally of the order of 1, the fuel jets of the two layers do not overlap (FIG. 4) and that the combustion has used almost all the oxidant present in the zone Z1 (Figure 4A-section along the line AA of Figure 4) and in the zone Z2 (Figure 4B-section along line BB of Figure 4). The variant of Figures 5, 5A, 6 and 6A differs from Figures 3 and 4 in that the orifices 33a and 33b of the two layers are on top of each other (Figure 5, zero phase shift b2).
    [0032] In this configuration, the fuel jets 40 of the lower ply are directed towards the bottom of the bowl 46 in the zone Z1 while the jets 42 of the upper ply are oriented towards the top of the bowl in the zone Z2 without the jets overlap each other (Figure 5A - cut along line AA of Figure 5).
    [0033] Similarly, it can be observed that during the final injection phase with a moderate number of swirls Ns, ideally of the order of 1, the fuel jets of the two layers do not overlap (FIG. 5) and that the fuel used almost all the oxidant present in zones Z1 and Z2 (FIG. 6A-section along the line AA of FIG. 6).
    [0034] Thus the use of such an injection system using a large number of holes favors the rapid mixing between the fuel injected and the oxidant by the drive mechanism in the jets. However, the number of holes must be adapted in each of the zones (Z1 and Z2) to the number of swirls Ns (via the two relations proposed, it will be possible to refer to FIG. 7) and to the shape of the piston (associated angles of plies ).
    [0035] This rapid mixing mechanism allows a greater homogenization thus limiting, during combustion, the generation of pollutants such as soot in areas with high fuel content or NOx in low fuel-rich areas. This non-pollutant generation allows an increase in the combustion efficiency and therefore a reduction in the specific consumption of this type of engine.
    权利要求:
    Claims (6)
    [0001]
    CLAIMS1) Direct injection internal combustion engine with compression ignition comprising at least one cylinder (10), a cylinder head (12) carrying fuel injection means (14), a piston (16) sliding in this cylinder, a combustion chamber (34) bounded on one side by the upper face (44) of the piston having a stud (48) extending towards the cylinder head and arranged in the center of a concave bowl (46) with at least two zones mixing device (Z1, Z2), said injection means comprising at least one injector (30) projecting fuel according to at least two plies (36, 38) of fuel jets of different angles of ply (Ai, A2), a lower layer (36) of jet axis Cl for zone (Z1) and an upper layer (38) of jet axis C2 for zone (Z2), characterized in that the fuel injector comprises at least two rows of injection ports (33a, 33b) placed one above the other and that number of orifices of each row (Ninf, Nsup) is greater than or equal to -4.Ns + 14 and smaller or equal than - 4.Ns + 16 for the bottom row or -4.Ns + 18 for the top row, or Ns is the swirl rate of this engine.
    [0002]
    2) Engine according to claim 1, characterized in that the minimum compression ratio is around 13.5 and the maximum compression ratio is around 16.5.
    [0003]
    3) Motor according to claim 1 or 2, characterized in that the number of swirl (Ns) is preferably less than 1.5 and even more preferably of the order of 1.
    [0004]
    4) Motor according to one of the preceding claims, characterized in that the orifices (33a) of the fuel jets (40) of a fuel ply (36) has an angular phase shift (b2) with the orifices (33b) of fuel jets (42) from the other fuel ply (38).
    [0005]
    5) Engine according to one of the preceding claims, characterized in that the fuel jet plies (36, 38) comprise a lap angle (Ai, A2) different from each other.
    [0006]
    6) A method of fuel injection for a direct injection internal combustion engine with compression ignition comprising at least one cylinder (10), a cylinder head (12) carrying fuel injection means (14), a piston ( 16) sliding in this cylinder, a combustion chamber (34) bounded on one side by the upper face (44) of the piston having a stud (48) erected towards the cylinder head and disposed in the center of a concave bowl (46), said method of injecting the fuel into at least two different ply angle fuel jet plies (A 1, A 2), a lower Cl axis spine (36) and an upper ply (38). ) of jet axis C2, characterized in that it consists in injecting the fuel by two rows of injection orifices (33a, 33b) placed one above the other and that a number of orifices each row (Ninf, Nsup) is greater than or equal to -4.Ns + 14 and smaller or equal than -4.Ns + 16 r the lower layer or -4.Ns + 18 for the upper layer or Ns is the number of swirls of this engine.
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    同族专利:
    公开号 | 公开日
    EP3134627B1|2020-08-05|
    CN107076007A|2017-08-18|
    FR3020401B1|2016-05-06|
    CN107076007B|2020-01-17|
    WO2015162005A1|2015-10-29|
    EP3134627A1|2017-03-01|
    US10024222B2|2018-07-17|
    US20170051657A1|2017-02-23|
    引用文献:
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    WO2013016713A2|2011-07-27|2013-01-31|Deyang Hou|Methods for low temperature combustion and engines using the same|
    EP2615296A1|2012-01-16|2013-07-17|Ford Global Technologies, LLC|Method and apparatus for injecting fuel into the combustion chamber of an internal combustion engine|
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    JP2002285849A|2001-03-23|2002-10-03|Isuzu Motors Ltd|Combustion system for diesel engine|
    US6755359B2|2002-09-12|2004-06-29|The Boeing Company|Fluid mixing injector and method|
    CN1332126C|2004-08-31|2007-08-15|侯德洋|Combustion system and method for self adaption controllable heat premixing direct jet type diesel engine|
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    DE102011017479A1|2011-04-19|2012-10-25|Daimler Ag|Internal combustion engine|
    US9022006B2|2011-11-04|2015-05-05|Enock N Segawa|Method and devices for process intensified wall integrated operations for IC engines|
    FR3012522B1|2013-10-25|2018-08-24|IFP Energies Nouvelles|COMBUSTION ENGINE WITH DIRECT INJECTION OF COMPRESSION IGNITION FUEL AND FUEL INJECTION METHOD FOR SUCH ENGINE.|
    FR3018552B1|2014-03-14|2019-07-05|IFP Energies Nouvelles|COMBUSTION ENGINE WITH DIRECT INJECTION OF COMPRESSION IGNITION FUEL COMPRISING PISTON COOLING MEANS.|
    FR3018550B1|2014-03-14|2019-04-12|IFP Energies Nouvelles|METHOD FOR CONTROLLING FUEL INJECTION OF AN INTERNAL COMBUSTION ENGINE WITH DIRECT INJECTION, ESPECIALLY COMPRESSION IGNITION, AND ENGINE USING SUCH A METHOD|
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    FR3018550B1|2014-03-14|2019-04-12|IFP Energies Nouvelles|METHOD FOR CONTROLLING FUEL INJECTION OF AN INTERNAL COMBUSTION ENGINE WITH DIRECT INJECTION, ESPECIALLY COMPRESSION IGNITION, AND ENGINE USING SUCH A METHOD|
    JP6485489B2|2017-05-23|2019-03-20|マツダ株式会社|ENGINE CONTROL DEVICE AND ENGINE CONTROL METHOD|
    DE102018006635B4|2018-08-22|2020-07-09|Daimler Ag|Method for operating an internal combustion engine for a motor vehicle, and internal combustion engine for a motor vehicle|
    CN109339943B|2018-09-01|2021-04-20|哈尔滨工程大学|Natural gas direct injection dual-fuel engine combustion system with tumble combustion chamber|
    US10731544B2|2018-09-24|2020-08-04|Caterpillar Inc.|Internal combustion engine and method for its operation|
    CN109854359B|2018-10-30|2020-10-27|中国北方发动机研究所|Swirl groove type combustion chamber suitable for vortex combustion system|
    CN112879148A|2021-01-25|2021-06-01|华中科技大学|Asymmetric combustion chamber system suitable for high power density diesel engine|
    法律状态:
    2015-04-14| PLFP| Fee payment|Year of fee payment: 2 |
    2015-10-30| PLSC| Publication of the preliminary search report|Effective date: 20151030 |
    2016-04-20| PLFP| Fee payment|Year of fee payment: 3 |
    2017-04-26| PLFP| Fee payment|Year of fee payment: 4 |
    2018-04-13| PLFP| Fee payment|Year of fee payment: 5 |
    2019-04-25| PLFP| Fee payment|Year of fee payment: 6 |
    2020-04-29| PLFP| Fee payment|Year of fee payment: 7 |
    2022-01-07| ST| Notification of lapse|Effective date: 20211205 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1453660A|FR3020401B1|2014-04-24|2014-04-24|DIRECT INJECTION INTERNAL COMBUSTION ENGINE HAVING A DOUBLE ANGLE OF FLOOR FOR CARRYING A CARBIDE MIXTURE IN A COMBUSTION COMBUSTION CHAMBER WITH A LOW COMBUSTION RATE AND A LOW COMPRESSION RATE AND METHOD FOR USING THE SAME.|FR1453660A| FR3020401B1|2014-04-24|2014-04-24|DIRECT INJECTION INTERNAL COMBUSTION ENGINE HAVING A DOUBLE ANGLE OF FLOOR FOR CARRYING A CARBIDE MIXTURE IN A COMBUSTION COMBUSTION CHAMBER WITH A LOW COMBUSTION RATE AND A LOW COMPRESSION RATE AND METHOD FOR USING THE SAME.|
    EP15713911.4A| EP3134627B1|2014-04-24|2015-04-08|Internal combustion engine having a double angled direct injection to produce a fuel mixture in a combustion chamber with a double combustion zone and a low compression ratio and method for its use in an engine.|
    PCT/EP2015/057594| WO2015162005A1|2014-04-24|2015-04-08|Direct-injection internal combustion engine with dual cone angle for producing a fuel mixture in a dual zone combustion chamber with a low compression rate and method for using such an engine|
    US15/306,434| US10024222B2|2014-04-24|2015-04-08|Direct-injection internal-combustion engine with dual sheet angle for producing a fuel mixture in a combustion chamber with dual combustion zone and low compression ratio, and method for using same|
    CN201580021045.XA| CN107076007B|2014-04-24|2015-04-08|Direct injection internal combustion engine with double cone angle for producing a fuel mixture in a dual zone combustion chamber having a low compression ratio and method of using the same|
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