A gas intake manifold that creates aerodynamic movement of gas within a cylinder

Abstract

The present invention relates to a gas intake pipe (2) for a cylinder of a heat engine, the intake pipe comprising means for deflecting the gas so as to generate a tumbling-type aerodynamic movement of the gas inside the cylinder, the deflecting means comprising at least a "ramped" shape (6) on the lower profile (12) of the intake pipe and a concave area on the upper profile (10) of the intake pipe (2).

Description

[Technical field]

[0001] The present invention relates to the field of gas intake pipes for internal combustion engines, in particular to gas intake pipes capable of generating an aerodynamic gas movement inside the engine cylinder. [Background technology]

[0002] This type of engine generally comprises at least one cylinder, a piston sliding in a reciprocating translatory motion within the cylinder, intake means for an oxidizer, combustion gas exhaust means, a combustion chamber, and injection means for injecting fuel.

[0003] It is generally recognized that when designing engines, the performance and pollutant emission constraints are becoming ever higher, requiring new solutions to be found in order to increase the ultimate engine efficiency.

[0004] Increasing combustion efficiency is thus key to limiting emissions for comparable or better performance, and it is therefore very important that all of the fuel present in the combustion chamber is used by the oxidizer, which may include, for example, ambient air, supercharged air, or a mixture of air (supercharged or not) and recirculated combustion gases.

[0005] In fact, the fuel mixture (oxidizer / fuel) in the combustion chamber needs to be as homogeneous as possible.

[0006] Furthermore, to ensure good efficiency and combustion rate, it is desirable to have a high turbulence level, and more specifically a high turbulent kinetic energy level, during ignition and subsequent combustion of the fuel mixture.

[0007] This high turbulence level can be achieved by certain intake aerodynamics, namely tumble (rotational motion of the gases in the cylinder about the longitudinal axis of the engine), or swunble. The latter type of aerodynamics is characterized in that the macroscopic motion of the fuel mixture is a combination of swirl (rotational motion of the gases in the cylinder about the axis of the cylinder) and tumble (rotational motion of the gases in the cylinder about the longitudinal axis of the engine, which is generally perpendicular to the axis of the cylinder).

[0008] Swirl, the macroscopic rotational motion of the fuel mixture around an axis collinear with the cylinder axis, is characterized by good conservation of motion during the intake process, more specifically during the ascent of the piston. It is an aerodynamic macroscopic motion commonly used for compression ignition internal combustion engines, and is a good method of homogenizing the fuel mixture for such engines.

[0009] Tumble is also a macroscopic rotational motion of the fuel mixture, but around an axis that is globally perpendicular to the cylinder axis. It has the unique feature of transforming into a microscopic aerodynamic motion that creates turbulence as the piston rises. It is a commonly used aerodynamic macroscopic motion for spark ignition internal combustion engines, and is a good way to obtain adequate burning rates for such engines. This motion is also very sensitive to the combustion chamber geometry and lift law in terms of spread as well as maximum lift height.

[0010] The use of a swanble allows one to benefit from the advantages of the two aerodynamic structures detailed above, thanks to a higher level of turbulence during the compression phase than is observed in the best current spark ignition engines, and therefore from superior homogenization and better combustion rates.

[0011] Various technical solutions have been developed to achieve these turbulent flows within the cylinder.

[0012] A first solution is described in particular in US Pat. No. 6,606,975. This solution consists in controlling flaps arranged in the intake pipe so as to generate turbulence. The patent further refers to the concept of low load swirl. Such a solution is complex and has disadvantages with regard to cylinder filling.

[0013] The second solution is described in particular in US Patent No. 5,056,486. This solution provides an asymmetric intake manifold definition that allows to generate complex aerodynamics. However, this solution requires a phase shift of the intake valve opening, which is a disadvantage at high loads.

[0014] A third solution is described in particular in the patent applications DE 10128500 A1 and EP 1783341 A1. This solution makes it possible to generate complex aerodynamics by using passive or active attachments in the intake manifold. In any case, these attachments limit the cylinder filling with gas. Moreover, active attachments require control systems that make such a solution more complex. [Prior art documents] [Patent documents]

[0015] [Patent Document 1] U.S. Patent No. 6,606,975 [Patent Document 2] U.S. Pat. No. 5,056,486 [Patent Document 3] German Patent No. 10128500 [Patent Document 4] European Patent Application Publication No. 1783341 Summary of the Invention [Problem to be solved by the invention]

[0016] To overcome these drawbacks, the present invention relates to a gas intake device for a cylinder of a heat engine. The tube comprises means for deflecting the gas so as to generate a tumbling-type aerodynamic movement of the gas in the cylinder. The deflection means comprise at least the shape of a "tremplin" on the lower profile (intrados) of the tube and a concave-shaped area on the upper profile (extrados) of the tube. The goal of the present invention is to generate a tumbling-type aerodynamic movement of the gas in the cylinder without flaps being placed in the tube, without an opening phase shift of the intake tube and without passive or active appendages in the intake tube. The "tremplin" is understood to be an element that promotes the separation of the gas flow from the lower profile. This ramp shape and this concave-shaped area are dimensioned to generate a high-velocity gas flow, which in turn allows to generate a defect-free tumbling-type turbulence. The tube according to the present invention further offers an interesting compromise between a tumbling-type aerodynamic gas movement and cylinder filling.

[0017] The invention further relates to such an intake manifold equipped with means for generating swirl (and therefore swambule). [Means for solving the problem]

[0018] The invention relates to a gas intake pipe for a cylinder of an internal combustion engine, the intake pipe comprising a deflection means for deflecting the gas so as to generate an aerodynamic movement of the gas in the cylinder about an axis substantially perpendicular to the axis of the cylinder, the deflection means comprising a ramp shape on a lower profile of the intake pipe and a concave shape of an upper profile of the intake pipe, the lower and upper profiles of the intake pipe being defined in the position of use of the intake pipe, the radius of curvature of the lower profile forming the ramp is less than 40 mm, the concave shape of the upper profile comprises an intermediate region with a radius of curvature in the range between 50 mm and 150 mm and a final region with a radius of curvature in the range between 10 mm and 100 mm, the final region facing the ramp shape of the lower profile.

[0019] According to one embodiment, the radius of curvature of the lower profile forming the ramp lies in the range between 20 mm and 30 mm, preferably in the range between 25 mm and 27 mm.

[0020] According to one implementation, the radius of curvature of the intermediate region is in the range between 100 mm and 130 mm.

[0021] According to one embodiment, the radius of curvature of the final region is in the range between 60 mm and 70 mm.

[0022] According to one embodiment, said lower profile comprises a concave initial region with a radius of curvature R5 ranging between 200 mm and 350 mm, preferably between 230 mm and 300 mm, more preferably between 270 mm and 280 mm.

[0023] Advantageously, the arc length of the ramp shape is in the range between 6% and 9% of the arc length of the concave shape of the initial region of the lower profile, and preferably corresponds substantially to 1 / 13 of the arc length of the concave shape of the initial region of the lower profile.

[0024] According to one implementation, the upper profile comprises an initial region of convex shape, preferably the radius of curvature of the initial region of the upper profile is equal to or greater than 400 mm.

[0025] Preferably, the arc length of said initial region of said upper profile is substantially equal to the sum of the arc lengths of said intermediate and final regions of said upper profile.

[0026] Advantageously, the ratio of the maximum cross-sectional area of ​​said intake manifold to the minimum cross-sectional area ranges between 1 and 2, preferably being 1.5.

[0027] According to one embodiment, the means for deflecting the gas further comprises an inclination of the intake manifold, defined by an angle β of a tangent at the intersection of the intake manifold with the outlet of the intake manifold, in the range between 0° and 45°, preferably in the range between 5° and 45°.

[0028] According to a feature, the intake pipe comprises means for generating an aerodynamic movement of the gas within the cylinder, around an axis parallel to the axis of the cylinder.

[0029] The invention also relates to a gas intake device for a cylinder of an internal combustion engine, comprising an intake pipe according to any one of the above characteristics, at least one intake valve arranged in the intake pipe, and at least one calibration of the intake valve arranged at one end of the intake pipe and directed towards a firing surface of the cylinder, wherein on the lower profile of the intake pipe, the intersection of the intake pipe and the calibration of the intake valve lies on a generatrix that makes an angle α ranging between 5° and 45° with a plane that passes through the intersection between the intake pipe and the calibration and is parallel to the firing surface of the cylinder.

[0030] According to one embodiment, said angle α ranges between 5° and 20°, preferably between 8° and 15°.

[0031] The invention further relates to an internal combustion engine comprising at least one intake pipe according to one of the above characteristics, at least one exhaust pipe and at least one cylinder provided with fuel injection means.

[0032] The invention further relates to the use of an internal combustion engine according to one of the above characteristics for a Miller cycle or an Atkinson cycle.

[0033] Other features and advantages of the device according to the invention will become apparent from reading the following specification, given by way of non-limiting example, with reference to the attached drawings, in which: [Brief description of the drawings]

[0034] [Figure 1] 2 shows an intake manifold according to an embodiment of the present invention in its operating position; FIG. [Diagram 2] FIG. 2 is a diagram showing the parameters of an intake manifold according to an embodiment of the present invention in its operating positions; [Diagram 3] 1A and 1B are views showing the intrados of intake devices according to first and second variants of the invention, respectively in their operating positions; [Figure 4] 1 shows a cylinder of an internal combustion engine according to an embodiment of the present invention in its operating position; [Diagram 5] 4 is a graph of the tumble vs. permeability tradeoff for a prior art intake tube and a tube according to the present invention; [Figure 6] FIG. 2 shows curves of the tumble number, the turbulent kinetic energy (TKE) and the swirl number within the context of standard laws for an intake system according to a first variant of the invention and for an intake system according to a second variant of the invention. [Figure 7] FIG. 2 shows curves of tumble number, turbulent kinetic energy (TKE) and swirl number within the context of Miller's law for an intake system according to a first variant of the invention and for an intake system according to a second variant of the invention. [Figure 8] FIG. 2 shows the curve of the evolution of the intake manifold cross section as a function of the distance of the measurement plane relative to the intake manifold inlet. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] The present invention relates to a gas intake manifold for a cylinder of an internal combustion engine. Such an intake manifold is provided with an inlet through which gas flows and an outlet through which gas flows out into the cylinder.

[0036] According to the invention, the intake manifold comprises means for deflecting the gas so as to generate an aerodynamic movement of the gas in the cylinder around an axis substantially perpendicular to the axis of the cylinder. In other words, the intake manifold comprises means for generating an aerodynamic movement of the gas of the tumble type in the cylinder. It is recalled that the tumble has the particular feature of transforming into a microscopic aerodynamic movement that creates turbulence as the piston rises. The tumble is an aerodynamic macroscopic movement commonly used in spark ignition-internal combustion engines and is a good way to obtain a good combustion speed in spark ignition-internal combustion engines. This movement is also very sensitive to the combustion chamber geometry and the lift law, in terms of its spread as well as its maximum lift height.

[0037] The intake manifold consists of a lower profile (intrados) and an upper profile (extrados) defined in the working position of the intake manifold. The lower and upper profiles are connected by two side walls.

[0038] The gas deflection means consists of a concave "tremplin" on the lower profile (intrados) of the intake pipe and a concave shape of the upper profile (extrados) of the intake pipe. The ramp shape promotes the separation of the gas flow in the intake pipe and directs the gas to the upper part of the intake pipe and therefore to the upper part of the cylinder so as to maximize the aerodynamic movement of the gases of the tumble type. The concave shape of the upper profile gives the intake pipe a convergent shape that promotes the gas velocity increase. Moreover, this combination of the ramp shape and the concave shape of the upper profile gives aerodynamic gas movement of the tumble type without any specific attachment of the mask type, flap type or blade type.

[0039] The ramp shape of the lower profile is achieved by means of a curvature of the lower profile with a radius of curvature of 40 mm or less. The concave of the upper profile is achieved by two successive concave regions in the direction of gas flow, called the intermediate region and the final region, respectively. The final region of the upper profile faces the ramp shape of the lower profile in the intake pipe. This region is called final because it is located at the intake pipe outlet. The radius of curvature of the final region is in the range between 10 mm and 100 mm, while the radius of curvature of the intermediate region is in the range between 50 mm and 150 mm.

[0040] The combination of the ramp shape and the concave area with specific dimensions allows the creation of a high velocity gas flow, which in turn allows the creation of a flawless tumble type turbulence. Furthermore, the intake pipe according to the invention offers a good compromise between tumble and cylinder filling.

[0041] Advantageously, the radius of curvature of the final region may be smaller than that of the intermediate region, thus reducing the cross-sectional area and therefore increasing the gas velocity within the intake pipe.

[0042] Preferably, the radius of the ramp shape may range between 20 mm and 30 mm, more preferably between 25 mm and 27 mm, in order to improve the effect of the ramp without restricting the filling of the cylinder. Indeed, the smaller the radius of curvature of the ramp area, the more the intake pipe promotes the generation of aerodynamic gas movements of the tumble type at the expense of the cylinder filling. On the other hand, the larger the radius of curvature of the ramp area, the more the intake pipe promotes the filling of the cylinder at the expense of the generation of aerodynamic gas movements of the tumble type.

[0043] Advantageously, the radius of curvature of the middle region of the upper profile may range between 100 mm and 300 mm, which range allows optimizing the occurrence of the convergence effect.

[0044] Advantageously, the radius of curvature of the final region of the upper profile may range between 60 and 70 mm, which range also allows optimizing the occurrence of the convergence effect.

[0045] According to one embodiment of the invention, the lower profile (intrados) of the intake manifold can include an initial region of concave shape. This region is called initial because it is close to the intake manifold inlet. The initial region of the lower profile determines the general shape of the manifold and influences parameters such as the filling and the robustness of the intake manifold. The initial region is directly followed by a ramp-shaped region.

[0046] In this embodiment, the radius of curvature of the initial region of the lower profile can be in the range between 200 mm and 350 mm, preferably between 230 mm and 300 mm, more preferably between 270 mm and 280 mm, these ranges allowing the optimum filling and robustness of the intake manifold.

[0047] Furthermore, for this embodiment, the arc length of the ramp shape can range between 6% and 9% of the arc length of the concave initial region of the lower profile, and preferably the arc length of the ramp shape can substantially correspond to 1 / 13 of the arc length of the concave initial region of the lower profile, and this ratio between the arc lengths of the lower profiles is ideal for the generation of tumble-type aerodynamic gas movements.

[0048] According to one realization of the invention, the upper profile (extrados) of the intake manifold can include an initial region of convex shape (in the gas flow direction through the intake manifold). This region is called initial because it is close to the intake manifold inlet. The convex initial region of the upper profile determines the inlet cross section of the intake manifold. Preferably, the initial region of the upper profile is geometrically similar to the initial region of the lower profile. The initial region is directly followed by an intermediate region, which itself is directly followed by a final region. For this realization of the invention, the upper profile includes three regions with clearly distinguishable radii of curvature.

[0049] For this realization of the invention, the radius of curvature of the convex initial region of the upper profile can be greater than 400 mm, so that it is large.

[0050] Further, for this implementation of the invention, the arc length of the convex initial region can be substantially equal to the sum of the arc lengths of the intermediate and final regions of the upper profile, and the ratio between the arc lengths of this upper profile is ideal for generating tumble-type aerodynamic motion.

[0051] According to one aspect of the invention, the tube convergence, i.e. the progression of the cross-sectional area of ​​the intake tube, can be selected such that the ratio between the maximum cross-sectional area of ​​the intake tube and the minimum cross-sectional area of ​​the intake tube is in the range between 1 and 2, and preferably the ratio is 1.5. Thus, a proper vortex tumble can be formed.

[0052] According to one aspect of the invention, the passage cross section of the intake pipe can have a generally rectangular shape with rounded corners, in which case the intersection of the intake pipe with the calibration part of the valve consists of four edges, i.e. one edge on the intrados side, one edge on the extrados side and two lateral edges.

[0053] According to a feature of the invention, the cross-sectional shape of the intake manifold can include a horizontal straight section in its lower region in its operating position, which shape promotes the generation of a swath-type aerodynamic movement.

[0054] According to one exemplary embodiment, the gas deflection means may further include an inclination of the intake pipe. This inclination of the intake pipe may be defined by an angle β of the tangent at the intersection of the intake pipe with the calibration section, which is in the range between 0° and 45°, preferably in the range between 5° and 45°. This inclination may be combined with the gradient of the upper combustion chamber of the cylinder. The inclination of the intake pipe may tilt the gas flow entering the cylinder to form a tumble-type aerodynamic gas movement. For example, an optimization of the tumble-type aerodynamic gas movement may be obtained using the tangence between the angle β and the angle of the gradient of the upper combustion chamber.

[0055] According to one embodiment of the present invention, the intake pipe may further comprise a means for generating an aerodynamic gas movement around an axis collinear with the cylinder axis within the cylinder. In other words, the intake pipe may comprise a means for generating a swirl type aerodynamic gas movement. Thus, in combination with the means for generating a tumble type aerodynamic gas movement, this embodiment may generate a swirling type aerodynamic gas movement.

[0056] It is recalled that swirl is characterized by a good preservation of the gas-fuel mixture during the intake process, and more specifically during the rise of the piston. It is an aerodynamic macroscopic motion commonly used in compression ignition internal combustion engines, in which it is a good way to homogenize the fuel mixture.

[0057] The use of swirl benefits from the advantages of both tumble and swirl aerodynamic structures, and therefore from superior homogenization and better combustion rates thanks to higher turbulence levels during the compression phase than those observed in the best current spark ignition engines.

[0058] Furthermore, the invention relates to a gas intake device for a cylinder of an internal combustion engine.

[0059] The gas intake device is a gas intake pipe for supplying gas to the cylinder according to any one of the combinations of the variants described above, i.e. a gas intake pipe provided with gas deflection means for generating an aerodynamic movement of the tumble type and, if necessary, of the swann type; an intake valve inserted in the intake pipe, which allows gas to flow into the cylinder when the valve is opened; an intake valve calibration part arranged at the end of the intake valve on the cylinder side, the calibration part being a substantially cylindrical mechanical part along which the valve moves and facing the firing surface of the cylinder; Equipped with.

[0060] The face feu or face combustion is understood to be the lower face of the cylinder head (of an internal combustion engine) perpendicular to the cylinder axis. The valve calibrator is inserted into the lower face of the cylinder head to supply gas to the cylinder.

[0061] According to one embodiment of the invention, the intake system is formed in such a way that in the intrados (lower profile) of said intake pipe, the intersection of the intake pipe and the valve calibration section lies on a generatrix that passes through the intersection between the intake pipe and the valve calibration section and makes an angle α in the range between 5° and 45° with respect to a plane that passes through the intersection between the intake pipe and the valve calibration section and is parallel to the contact surface. The intrados of the intake pipe is understood to be the lower surface of the intake pipe. Thereby, the intersection of the lower surface of the intake pipe with the valve calibration section is inclined with respect to a plane that is parallel to the contact surface. This inclination allows the gases to be deflected at the inlet of the calibration section and also at the inlet of the cylinder. This deflection of the gases generates an aerodynamic gas movement in the cylinder in a direction parallel to the cylinder axis, in other words an aerodynamic gas movement of the swirl type. This inclination can lead to a rotation of the intake pipe at its end (the end of the intake pipe then twists) and promotes a swirling aerodynamic movement of the gases. Moreover, this embodiment allows the generation of aerodynamic gas movements of the swirl type without any specific attachments of the mask, flap or blade type, and the structure of these intake devices does not entail any additional constraints on their placement in the cylinder head of a single or multi-cylinder internal combustion engine.

[0062] An inclination angle α in the range between 5° and 45° allows the generation of a swirl-type aerodynamic gas motion. Below 5°, the inclination is insufficient to significantly affect the aerodynamic gas motion in the cylinder. Above 45°, the geometry of the intake manifold is complex and difficult to achieve, and the aerodynamics of the gas deteriorates.

[0063] By combining tumble and swirl aerodynamic gas movements, the gas intake system according to the invention provides a swirling aerodynamic gas movement in the cylinder, which makes it possible to benefit from superior homogenization and better combustion rates thanks to a higher turbulence level than observed in the best current spark ignition engines.

[0064] According to one embodiment of the invention, the angle α can range between 5° and 20°, preferably between 8° and 15°. These angle ranges make it possible to optimize the swirl type aerodynamic gas movements and therefore the combined swam type aerodynamic gas movements.

[0065] According to one realisation of the invention, the calibration section may comprise a mask partially covering the calibration section outlet so as to direct the gas within the cylinder and thus promote aerodynamic movement of the gas.

[0066] The gas may be an oxidizer or a fuel mixture (indirect injection) and may include air at ambient pressure, supercharged air, or a mixture of air (supercharged or not) and combustion gases, among others.

[0067] Figure 1 shows, by way of non-limiting example, a schematic representation of an intake system in an operating mode position according to an embodiment of the invention. Figure 1 shows a side view. The intake system 1 comprises an intake pipe 2, a valve (not shown) and a calibration part 4 of the intake valve.

[0068] The intake manifold 2 has an upper profile 10 (extrados) and a lower profile 12 (intrados). The upper profile 10 and the lower profile 12 are connected by two side walls 15. The various regions of the upper and lower profiles are delimited by thick lines with points P1 to P7.

[0069] The lower profile 12 comprises a region forming a concave ramp 6 at the intake manifold outlet, bounded by points P1 and P2. The radius of curvature R1 of this region is less than 40 mm, for example equal to 26 mm. The lower profile 12 further comprises a concave initial region 11 bounded by points P2 and P3. The radius of curvature R5 of this region lies in the range between 200 mm and 350 mm, for example equal to 275 mm.

[0070] The upper profile 10 comprises, at the intake manifold outlet, a concave final region 5 bounded by points P4 and P5. The radius of curvature R2 of this final region 5 lies between 10 mm and 100 mm, for example equal to 65 mm. The upper profile 10 further comprises a concave intermediate region 8 bounded by points P5 and P6. The radius of curvature R3 of this intermediate region 8 lies between 50 mm and 150 mm, for example equal to 115 mm. The upper profile 10 additionally comprises a convex initial region 9 bounded by points P6 and P7. The radius of curvature R4 of this initial region is greater than 400 mm, for example equal to 500 mm.

[0071] Figure 2 is a view similar to figure 1 for an embodiment of the invention. In this embodiment, the gas deflection means intended to generate an aerodynamic gas movement of the tumble type further comprises an inclination of the intake pipe 2 at an angle β between a direction line XX, which is tangent to the intersection of the intake pipe 2 with the calibration part 4, and a horizontal line AA. This inclination promotes an aerodynamic movement of the gas of the tumble type.

[0072] Figure 3 shows diagrammatically, by way of non-limiting example, an intrados (lower surface) view of a gas intake device, which is in a plane perpendicular to the contact surface. The left view corresponds to a device according to a first variant of the invention, which only has gas deflection means for generating an aerodynamic gas movement of the tumble type. The right view corresponds to a device according to a second variant of the invention, which comprises gas deflection means for generating an aerodynamic gas movement of the tumble type and a slope of the intersection between the intake pipe and the valve calibrator in the intrados to generate an aerodynamic gas movement of the swirl type.

[0073] In these figures, the line FF belongs to the plane of the firing surface (defined by a cylinder not shown), and the direction line F'F' is a line belonging to a plane parallel to the firing surface FF that passes through the intersection of the intake pipe 2 and the intake valve calibration portion 4.

[0074] According to the first variant illustrated in the left-hand diagram, the intersection 7 between the intake manifold 2 and the intake valve calibration part 4 merges with the line F'F'.

[0075] On the other hand, according to the second variant shown in the right-hand diagram, the intersection 7 of the intake manifold 2 with the intake valve calibration part 4 lies on the generatrix of the axis YY inclined at an angle α to the line F'F'. This angle α lies in the range between 5° and 45°. It can be seen in the right-hand diagram that this inclination generates a slight rotation of the intake manifold 2, which has an approximately rectangular cross section, close to the connection.

[0076] FIG. 8 is a curve representing the cross-section ratio RS as a function of the distance D of the cross-section relative to the intake manifold inlet in an exemplary embodiment of the invention. The cross-section ratio RS corresponds to the area of ​​the cross-section considered relative to the area of ​​the intake manifold cross-section at the inlet. The distances are normalized, with a distance of 0 corresponding to the intake manifold inlet and a distance of 1 corresponding to the intake manifold outlet. The curve shows an initial quasi-constant, then a drop in the cross-section ratio due in particular to the ramp shape and the final region of the upper profile, followed by a sharp increase in the cross-section ratio at the intake manifold outlet. In this example, the ratio of the maximum cross-section to the minimum cross-section of the intake manifold is approximately 1.8.

[0077] The invention also relates to an assembly comprising a cylinder of an internal combustion engine and an intake device according to one of the variants or a combination of variants described above.

[0078] Furthermore, the invention relates to a cylinder-intake system assembly according to one of the variants or combinations of variants described above for supplying gas to a cylinder.

[0079] The present invention further provides a method for manufacturing a liquid crystal display comprising the steps of: At least one intake device according to any one of the preceding variants or combinations of variants for supplying gas to the cylinder; at least one exhaust device for discharging the combustion gases from the cylinder, the exhaust device advantageously comprising an exhaust valve; A piston that moves back and forth within a cylinder to generate mechanical energy from combustion (by rotation of the crankshaft); a fuel injection means for generating combustion; The present invention relates to an internal combustion engine equipped with

[0080] According to one embodiment, the fuel injection means may be direct injection means, i.e. the fuel injection means is arranged directly in the cylinder.

[0081] Alternatively the fuel injection means may be indirect injection means, i.e. the fuel injection means is located within the intake system.

[0082] According to one realisation of the invention, the internal combustion engine is a spark ignition engine, in which case the engine further comprises at least one plug for generating the combustion of the gas / fuel mixture.

[0083] Alternatively, the internal combustion engine may be a compression ignition engine, in which case the engine does not have a plug to create the combustion of the gas / fuel mixture.

[0084] According to one aspect of the invention, when the cylinder is equipped with two intake pipes, these two pipes can be identical and parallel to the central plane of the combustion chamber.

[0085] In one variation, gas can be supplied to the cylinder through a Siamese intake system.

[0086] The internal combustion engine may include a number of cylinders, in particular three, four, five or six cylinders.

[0087] The cylinder bore can be of any size, however the present invention is particularly suitable for a cylinder diameter of about 75 mm.

[0088] 4 shows, by way of non-limiting example, a schematic partial view of a cylinder of an internal combustion engine in an operating mode position according to an embodiment of the invention. The cylinder 13, in which a piston (not shown) moves, comprises a combustion chamber 14. The intake system 1, in particular the valve calibrator 4, opens into the combustion chamber 14. An exhaust system (not shown) is also arranged in the combustion chamber 14.

[0089] The axial direction of the cylinder 13 is designated CC. The figure also shows the firing surface FF, which is perpendicular to the axis CC and corresponds to the lower part of the cylinder head (not shown) of the internal combustion engine.

[0090] The intake system 1 is identical to the intake system of FIGS. 1, 2 and 3 and in particular comprises an intake pipe 2, a valve 3 and a valve calibration part 4.

[0091] Furthermore, the invention relates to the use of an internal combustion engine according to one of the variants or combinations of variants mentioned above in connection with a Miller cycle or an Atkinson cycle.

[0092] The Miller cycle is a thermodynamic cycle characterized by the closure of the intake valve during the intake phase before the bottom dead center of the piston, which improves the recovery of work in addition to cooling the intake charge. The intake device according to the invention is particularly suitable for use in so-called Miller cycles over a wide operating range, thanks to the generation of a swam-type aerodynamic movement of the gas.

[0093] The Atkinson cycle is a thermodynamic cycle that is used especially in variable speed internal combustion engines.

[0094] The internal combustion engine according to the invention can be used in the field of load applications, such as road, sea or air transport, or in stationary installations, such as power plants. EXAMPLES

[0095] The features and advantages of the intake manifold according to the invention will become apparent from reading the application examples that follow.

[0096] FIG. 5 is a graph of the tumble coefficient as a function of the permeability coefficient Cf. The tumble coefficient is defined as the ratio of the angular velocity of the gas around the center of mass in the direction x (perpendicular to the cylinder axis) to the angular velocity of the crankshaft, and the permeability coefficient corresponds to the capacity of the intake pipe to allow the passage of an air flow with respect to the available cross-sectional area. The permeability coefficient is thus related to the cylinder filling. In the figure, the intake pipe AA according to the prior art available on the market is represented by a triangle, and the intake pipe INV according to the invention is represented by a square. It is clear that the intake pipe INV according to the invention offers a better compromise between high tumble coefficient and permeability coefficient than the solution from the prior art AA. In fact, for the same permeability coefficient Cf, the tumble coefficient obtained with the intake pipe according to the invention is twice as high as that obtained with the intake pipe according to the prior art.

[0097] For a second example, the characteristics of an internal combustion engine equipped with an intake system according to the first variant, which has only a tumble-type aerodynamic movement of the gases (corresponding to the left side in FIG. 3), are compared with the same internal combustion engine equipped with an intake system according to the second variant of the invention, which has a swam-type aerodynamic movement of the gases (corresponding to the right side in FIG. 3). In this example, the value of the angle α is 15°.

[0098] Figure 6 shows the curves of tumble number T (top left), turbulent kinetic energy TKE (top right) and swirl number S (bottom left) as a function of crank angle °Vil for the part of the engine cycle from intake bottom dead center (360°) to compression top dead center (720°). The diagram on the bottom right shows the turbulent kinetic energy TKE for a reduced angular range area at crank angle °Vil close to the combustion occurring after compression top dead center (720° crank angle). The tumble number in direction x is defined as the ratio of the angular velocity of the gas around the center of mass in direction x (perpendicular to the cylinder axis) to the angular velocity of the crankshaft. The swirl number is defined as the ratio of the angular velocity of the gas around the center of mass in the cylinder axis direction to the angular velocity of the crankshaft. The tumble number and the swirl number are dimensionless.

[0099] 6 relates to a standard cycle. In these figures, the curve corresponding to the internal combustion engine equipped with the intake system based on the first modification is designated INV1, and the curve corresponding to the internal combustion engine equipped with the intake system based on the second modification of the present invention is designated INV2.

[0100] Turbulence kinetic energy (TKE) represents the amount of energy "trapped" within the air mass.

[0101] It should be noted in these figures that the two intake devices make it possible to generate aerodynamic movements of the tumble type (high tumble number T). Furthermore, it should be noted that the swirl number S is much higher for the intake device INV2 according to the second variant. Thus, the inclination of the intersection of the intake pipe with the calibrated part makes it possible to generate effectively aerodynamic movements of the swirl type. The device according to the second variant thus makes it possible to generate effectively aerodynamic movements of the swirl type (tumble and swirl). Furthermore, it should be noted that the intake device according to the second variant offers a gain in turbulent kinetic energy TEK compared to the first variant, by allowing this turbulent energy to increase before combustion.

[0102] FIG. 7 shows the curves of the tumble number T (top left), the turbulent kinetic energy TKE (top right) and the swirl number S (bottom left) as a function of the crank angle °Vil for the part of the engine cycle from intake bottom dead center (360°) to compression top dead center (720°). The diagram on the bottom right shows the turbulent kinetic energy TKE for a reduced angular range area at crank angles °Vil close to the combustion occurring after compression top dead center (720° crank angle). FIG. 7 relates to the Miller cycle. In these figures, the curve corresponding to the internal combustion engine equipped with an intake device according to the first variant is called INV1 and the curve corresponding to the internal combustion engine equipped with an intake device according to the second variant is called INV2.

[0103] It should be noted in these figures that the two intake devices make it possible to generate aerodynamic movements of the tumble type (high tumble number T). Furthermore, it should be noted that the swirl number S is much higher for the intake device INV2 according to the second variant. Thus, the inclination of the intersection of the intake pipe with the calibrated part makes it possible to effectively generate aerodynamic movements of the swirl type. The device according to the second variant thus makes it possible to effectively generate aerodynamic movements of the swann (tumble and swirl) type. Furthermore, it should be noted that the intake device according to the first variant offers a gain in turbulent kinetic energy TEK compared to the first variant by allowing this turbulent energy to increase before combustion.

[0104] The generation of a swirl type aerodynamic gas motion thus allows a better conservation of the energy contained in the aerodynamic motion during the intake of the engine cycle, and therefore the turbulence level which initiates combustion is higher than in a purely tumble type tube, especially with respect to the lift law suitable for Miller cycle operation.

[0105] The use of the intake devices according to the invention results in a significant increase in the combustion efficiency, and furthermore, the configuration of these intake devices does not involve any additional constraints on their placement in the cylinder head of a single or multi-cylinder engine, which is a major advantage in comparison with existing solutions for generating swabs.

Claims

1. A gas intake pipe for a cylinder of an internal combustion engine, the intake pipe (2) comprising deflection means for deflecting the gas so as to generate an aerodynamic movement of the gas in the cylinder about an axis substantially perpendicular to the axis of the cylinder, the deflection means comprising a ramp shape on a lower profile (12) of the intake pipe and a concave shape of an upper profile (10) of the intake pipe (2), the lower and upper profiles (12, 10) of the intake pipe (2) being defined in a use position of the intake pipe (2), 1. An intake duct, characterized in that the radius of curvature R1 of the ramp (6) of the lower profile (12) is between 20 mm and 30 mm, and the concave shape of the upper profile comprises an intermediate region (8) with a radius of curvature R3 in the range between 100 mm and 130 mm and a final region (5) with a radius of curvature R2 in the range between 60 mm and 70 mm, the final region (5) facing the shape of the ramp of the lower profile (12).

2. An intake pipe as described in claim 1, wherein the radius of curvature R1 of the ramp (6) of the lower profile (12) is in the range between 25 mm and 27 mm.

3. An intake manifold according to claim 1 or 2, wherein the lower profile (12) comprises a concave initial region (11) with a radius of curvature R5 ranging between 200 mm and 350 mm.

4. 4. An intake manifold as claimed in claim 3, wherein the arc length of the ramp shape (6) is in the range between 6% and 9% of the arc length of the concave shape of the initial region (11) of the lower profile (12).

5. An intake manifold according to any one of the preceding claims, wherein the upper profile (10) comprises a convex initial region (9).

6. 6. An intake manifold as claimed in claim 5, wherein the arc length of the initial region (9) of the upper profile (10) is substantially equal to the sum of the arc lengths of the intermediate region (8) and the final region (5) of the upper profile (10).

7. 7. An intake manifold according to any one of claims 1 to 6, wherein the ratio of the maximum cross-sectional area of ​​the intake manifold (2) to the minimum cross-sectional area is in the range between 1 and 2.

8. 8. An intake manifold according to claim 1, wherein the deflection means for deflecting the gas further comprises an inclination of the intake manifold (2) in the range between 0° and 45°, determined by an angle β between a tangent to the lower profile at the intersection of the intake manifold (2) with the calibration portion (4) and the horizontal.

9. 9. An intake manifold (2) according to any one of the preceding claims, comprising means for generating an aerodynamic movement of the gas within the cylinder about an axis parallel to the axis of the cylinder.

10. A gas intake system (1) for a cylinder of an internal combustion engine, comprising an intake manifold (2) according to any one of claims 1 to 9, at least one intake valve (3) arranged in the intake manifold (2), and at least one calibrated part (4) of the intake valve (3) arranged at one end of the intake manifold (2) and directed towards a firing surface (FF) of the cylinder, 1. An intake system, characterized in that the flow passage cross section has a substantially rectangular shape with rounded corners, and on the lower profile of the intake pipe (2), an intersection (7) of the intake pipe (2) with the calibrated portion (4) of the intake valve (3) lies on a generatrix (YY) that makes an angle α in the range between 5° and 45° with a plane (F'F') that passes through the intersection (7) between the intake pipe (2) and the calibrated portion (4) and is parallel to the firing surface (FF) of the cylinder, so that the one end of the intake pipe is twisted.

11. 11. The intake system of claim 10, wherein the angle α is in the range between 5° and 20°.

12. An internal combustion engine comprising at least one cylinder equipped with at least one intake pipe (2) according to any one of the preceding claims, at least one exhaust pipe and fuel injection means.

13. 13. Use of an internal combustion engine according to claim 12 for a Miller cycle or an Atkinson cycle.

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