FR2954443A1 - VALVE FOR USE, IN PARTICULAR, TO BE IMPLANTED IN AN AIR INTAKE CIRCUIT OF A THERMAL ENGINE - Google Patents

Abstract

The invention relates to a valve (1) comprising a body and at least one flap (V1 ', V2', V3 ', V4') mounted on a shaft (A) to be movable between at least one closure position and a position of full opening of a duct (C'2, C'3, C'4, C'5), provided convergent and / or divergent, formed in the body, the flap having a peripheral edge (B'1) , intended to come into contact with the body of the valve, in continuity of material with the rest of the flap, the axis (X) of the shaft (A) being offset relative to a median plane (P) of the flap.

Description

RFR0564 Valve intended, in particular, to be installed in an air intake circuit of a heat engine

The present invention relates to a valve intended, in particular, to be implanted in an air intake circuit of a heat engine. The invention also relates to such an intake circuit. BACKGROUND OF THE INVENTION It is known to use valves to control the passage of air in the cylinders of a heat engine, these valves being controlled in order to optimize combustion by improving the fuel air mixture during operation. the admission phase. In order to improve combustion, it is possible, in particular, to use a device with supply ducts whose geometry allows the creation of a swirling air movement, also called "swirl" flow, in the chamber of combustion. This type of dis-positive is common in diesel injection engines: there are generally two supply ducts per cylinder, including a main duct and a secondary duct, the closure of the main duct allowing the creation of the "swirl" stream. . Whether in the specific context of creating a "swirl" current or in the more general context of the air circulation in an intake circuit, it is important to understand that the valves driving the flow rate of different air flows operate reliably and accurately. Thus, when they have to completely close off an air flow, any leakage leakage causes unwanted air leaks to create pressure drops and disturbances having a negative impact on the overall performance of the air. engine. 1 The valves are generally in the form of a body provided with a conduit in which one or more flaps are mounted on the same shaft. In the case of valves controlling the passage of air in the cylinders of a heat engine, generally there is a main duct and a secondary duct per cylinder. The shutters are each provided with a through sleeve disposed in the middle part of the flaps, in which the shaft is received, so that the axis of the shaft passes through the center of each flap, in its plane. . The rotation of the shaft, guided by bearings and actuated by motor means, causes the movement of the flaps of a closed position, where the flap rests against a shoulder (also called seat) in the duct, at a fully open position, where the flap is detached at the maximum of this shoulder, with different possible intermediate positions. The clearance between the flaps and their associated seats, on the one hand, between the shaft and its bearings, on the other hand allows the flaps to move correctly to and from their closed positions, minimizing both the risks of leakage between the edge of the shutters and their associated seats once the shutters in the closed position, and the risk of jamming flaps when they dock or leave their associated seats. However, this shutter design is subject to improvement. Indeed, in particular, the flap edge interface / associated seat when the flap is in the closed position is interrupted locally in two diametrically opposite zones to one another and corresponding to the passages of the traversing axis, which There is a potential risk of increased leakage in these specific zones along the housing of the shaft. OBJECTS OF THE INVENTION The subject of the invention is a valve whose design aims at minimizing the aforementioned drawbacks. It thus aims a valve of improved design, limiting at best the risk of leakage when one or more shutters mounted on the same shaft pass in the closed position, and, incidentally, also limiting any risk of jamming flaps when they are rotated while remaining simple in design.

GENERAL DEFINITION OF THE INVENTION The aforementioned problem is solved according to the invention by means of a valve comprising a body and at least one flap, mounted on a shaft to be movable between at least one closed position and a fully open position. a duct, provided convergent and / or divergent, formed in the body, the flap having a peripheral edge, intended to come into contact with the valve body, in continuity of material with the rest of the flap, the axis of the shaft being offset relative to a median plane of the flap. Within the meaning of the invention, a component comprises a component defining two opposite main faces, most often substantially flat and parallel between them, said flap being intended to pivot relative to an axis. The flap is here preferably butterfly type, and can adopt different geometric shapes, including having a circular circumference, oval, parallelepiped. It has a central axis, generally its axis of symmetry, passing through its center and which is normal to its principal facets. The middle plane of the shutter comprises a plane passing through the thickness of the flap, and substantially equidistant from its two main faces. The solution according to the invention already improves the seal in that it provides a convergent duct and / or divergent, which promotes contact between the flap and the duct in the closed position. In addition, according to the invention, the axis of the shaft is offset relative to the median plane of the flap which, at the same time, limits the risk of jamming and allows contact between the periphery of the shutter and the periphery of the seat associated which is continuous when the shutter is in the closed position. This continuous flap / seat contact over the entire circumference of the flap is extremely advantageous because it eliminates potential leakage problems at the discontinuity areas due to the passage of the traversing shaft in its prior known configuration. It is thus deported the shaft out of the seating area of the ducts, so that it no longer compromises the flap / seat seal when the flap is in the closed position. This provides a solution for improved sealing, while limiting the risk of jamming, this with a valve of particularly simple design since offering direct contact with the duct in the body is i.e. without the use of a seal or sealing segment. According to one embodiment, the axis of the shaft is further offset with respect to the central axis of the flap.

This further limits the risk of trapping flaps against the walls of the ducts when the flaps are rotated and without resorting to complicated forms of duct. The offset provided is sufficient for the flap to rotate appropriately to adopt all the positions provided from the full opening to the shutter, without its perimeter comes rubbing on the walls of the duct when it rotates, without risking problems. berthing when it arrives in its closed position against its associated seat.

BRIEF DESCRIPTION OF THE DRAWINGS Other characteristics and advantages of the invention will emerge more clearly in the light of the following description and the attached drawings, relating to a particular embodiment, with reference to the figures of the accompanying drawings in which: FIG. 1 illustrates a sectional view of a valve according to the prior art - FIG. 2 illustrates a perspective representation of a valve according to the invention without the shaft provided with its shutters; - Figure 3 illustrates a cross-sectional view of a shutter according to the invention in the closed position of a duct (the shaft on which the flap is mounted not being shown); - Figure 4 is a cross-sectional view of a shutter according to the invention according to Figure 3, in the closed position of the conduit which it is associated in the valve according to a first variant; - Figure 5 is a cross-sectional view of a shutter according to the invention according to Figure 3, in the closed position of the conduit which it is associated in the valve, according to a second variant. The set of figures is very schematic and does not necessarily respect the scale to facilitate reading, each represented element retaining the same reference in all figures. DESCRIPTION OF EMBODIMENTS OF THE INVENTION FIG. 1 is a very simplified cross-section showing the implantation of a valve according to the prior art in an air intake circuit of a heat engine. . There is shown a body 1 delimiting a main duct C into which three secondary ducts C1, C2, C3 open. In the body 1 is mounted a shaft A of axis X and transverse to the secondary ducts C1, C2, C3. On the shaft A, are mounted tightly three shutters V1, V2, V3. The shutters are here butterfly type. They have a substantially circular contour corresponding to the contour of the orifices through which the secondary ducts C1, C2, C3 open into the main duct C. The vo-lets comprise two opposite substantially plane faces and parallel to each other, except in a median zone crossing the shutter over its entire diameter and which defines a sleeve (not shown) in which is engaged the shaft A. When the shaft A rotates to bring the shutters in the closed position against the seats (not shown) of the secondary conduits C1, C2, C3 edges B1, B2, B3 of the flaps are supported on the seats, with however two contact discontinuities corresponding to two diametrically opposite passage zones A1, A'l of the shaft A. Even when the flaps are perfectly applied on their associated seats, there is a risk of leakage located in these areas A1, A'1 where the shaft A is in contact locally with each seat, risks that it is difficult to delete keeping this valve configuration. Figure 2 shows a valve according to the invention, which has been removed the shutters and the shaft that carries them for clarity. This figure will be described with FIG. 3, which represents a shutter of the valve according to the invention, and FIG. 4, which represents the same flap once in support, in the closed position, on the seat of its associated duct in valve. The valve according to the invention comprises a main duct and four secondary ducts C'2, C'3, C'4, C'5, here convergent, intended to be shut off on command by four flaps tightly mounted and in series on a shaft A mu rotated using motor means and not shown.

The valve thus consists of n modules, with, here, n equal to 4, each module having its secondary conduit and its associated flap opening into the main conduit. The axis X of the shaft A has been deported, so as not to cross the seats C'21, C'31, C'41, C'51 of the secondary ducts as follows. It can be seen in FIG. 2 that the drilling of the orifices 01 to 08 for receiving the shaft A is shifted forward, according to the figure, with respect to the positioning of the seats of the secondary ducts. As illustrated more precisely in Figure 3: the flap V1 '(and, identically, the other three flaps) is circular, defined by two flat faces F1, F2 connected by a side edge B'l thinned. This lateral surface B'1 can have a truncated or toric shape. The flap V1 'has a central Y axis of symmetry passing through its center 0, and a median plane P which passes substantially in the thickness of the flap in its middle, which is perpendicular to the central axis. This plane P is also, substantially, what can be designated by the so-called sealing plane, once the flap bears on the associated seat of the duct. The vo-let, in addition, is provided with a sleeve V'll in which is received the shaft A, the sleeve being arranged projecting from one side of one of the faces F1 of the flap. This sleeve delimits a passage section S intended to receive the shaft, section centered on the axis X of the shaft, and whose central axis, which is substantially the axis X of the shaft A, does not do not cross the central axis Y of the flap V1 '. According to the invention, the flap is made in continuity of material of the sleeve to its peripheral edge, coming into contact with the duct in the closed position. In other words, the shutter is mono-material, including its sleeve. As represented in FIG. 3, the axis X of the shaft A is offset relative to the median plane P of the flap of a given distance d1. This offset guarantees continuity of flap / seat contact, the shaft thus being deported out of the seating area of the secondary ducts. The axis X of the shaft A may also be offset relative to the central axis Y of the flap V1 'of a given distance d2 (the distance d2 being measured perpendicularly to the two axes). Thus, it imposes a minimum distance between the axis X of the shaft and the center 0 of the flap, so that the movement of the flap V'1 from one position to another, and especially when it docked or left the seat of the conduit C'2, is not thwarted by friction of its edge against the inner wall of the conduit. As detailed in FIG. 4, and according to a first variant, the shutter V1 '(and all other shutters in the same way) cooperates, in the closed position, with a seat C'21 present in the associated conduit C'2 , the seat having a scope pt at least partially in the form of a truncated cone whose Z axis is inclined with respect to the central axis Y of the flap in the closed position and / or with respect to the axis of the leads. Here, the central axis Y of the flap and the axis of the duct are merged. The scope of the seat intended to come into contact with the edge B'1 of the flap when it is in the closed position resting on the seat is understood by bearing.

The edge B'1 of the flap can be of curved, toric or frustoconical profile to facilitate the docking of the vo-let against the seat. Here, it is at least partially in the form of a sphere portion, thus a toric surface, whereas the seat span area on which it will rest when the shutter is in the closed position is tapered . Thus, in the closed position, a linear contact between the edge of the flap and its associated seat, with two advantages to this: firstly, it avoids jamming the flap when it leaves or arrives in its position d ' shutter, on the other hand, it ensures a good seal when it is in the closed position. The fact that the Z axis is inclined with respect to the axis X allows the flap V'l to pivot relative to the axis X without its edge comes jamming or rub excessive against the scope pt or the wall internal duct near the seat C'21. The inclination a is preferably between 0 ° and 20 °, in particular at least 2 or at least 50, and here about 10 to 150, which gives the flap the desired deflection relative to its duct. C'2 associated. It can thus be seen that, according to the invention, there may be an offset (angle α greater than 0 °) or not (angle α equal to 0 °). FIG. 5 represents a second variant of positioning the flap in the seat of the duct, in the closed position: here, the axis Z is not inclined with respect to the central axis Y of the flap in the closed position and or relative to the axis of the duct: there is no angular offset and the angle θ as shown in the figure is both the angle of the cone of the seat and that measuring the spacing the edges of the shutter. FIG. 5 represents, by the dashed lines, the trajectory of the flap V'l towards the seat C'21 of the associated duct. The angles and y as shown are the angles of the tangent to the path of the flap V'l in the closed position of the duct, measured in a plane perpendicular to the axis X of the shaft A and passing through the center 0 component V'l. According to the invention, and therefore also in the case of the variant shown in Figure 4, these two angles are at least 3 °, and are in particular between 5 and 15 °. They are here about 5 °. Preferably, the values of the angles p and y are chosen to be identical or similar. The choice of these angle values ensures a trajectory of the flap without friction or jamming.

According to the invention, the appropriate values are selected for the distances d1 and d2, and possibly, when it is provided, the inclination of the Z axis of the seat having a seat at least partially in the form of a truncated cone by relative to the central axis Y of the shutter in the closed position and / or with respect to the axis of the duct, so as to obtain the values of angles R and y in the range of values mentioned above. We have indeed a relation between dl, d2, 6, r (r being the radius of the shutter) and the offset of angle a, that it is null or not, and the angles R and y, which can be written The invention also relates to any intake circuit of a heat engine comprising at least one valve as described above. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention is not limited to the embodiments that have just been described, but on the contrary covers any variant using, with equivalent means, the essential characteristics mentioned above. Thus, in the example described, the flaps were mounted tight on the shaft, but they can indifferently be mounted sliding in translation on the shaft, preferably sliding in translation and not in rotation. The seat of the shutter can be defined by a shoulder-ment defining the range, or be devoid of such a shoulder, the shutter being in the closed position when it extends perpendicularly to the duct occupying the entire section of passage of it.

Similarly, the example described relates to a plurality of flaps mounted on the same shaft, but the invention also applies to a valve with a single flap mounted on a shaft.

The shutters can be metal, plastic material or composite material. In conclusion, the technical solution of the invention makes it possible to obtain a better tightness of the ducts when the shutters are in the closed position, by modifying the way in which the shaft is engaged in the shutters, but without making their manufacture more complex.

Claims (12)

REVENDICATIONS1. Valve (1) comprising a body and at least one flap (V1 ', V2', V3 ', V4'), mounted on a shaft (A) to be movable between at least one closed position and a fully open position a duct (C'2, C'3, C'4, C'5), provided convergent and / or divergent, formed in the body, the flap having a peripheral edge (B'1), intended for come into contact with the body of the valve, in continuity of material with the rest of vo-let, the axis (X) of the shaft (A) being offset relative to a median plane (P) of the shutter. 2. Valve according to claim 1 wherein the axis (X) of the shaft (A) is further offset relative to the central axis (Y) of the flap. 3. Valve (1) according to one of the preceding claims, characterized in that the flap (V1 ') is provided with a sleeve (Vil') in which the shaft (A) is received, the sleeve being disposed projecting from one side of one of the faces (F1, F2) of the flap. 4. Valve (1) according to the preceding claim, characterized in that the axis of the passage section of the sleeve (Vii ') does not cross the central axis (Y) of the flap (V1'). 5. Valve (1) according to one of the preceding claims, characterized in that a plurality of flaps (V1 ', V2', V3 ', V4') are connected in series on the same shaft (A). 30 35 6. Valve (1) according to one of the preceding claims, characterized in that the flap (V1 ', V2', V3 ', V4') is slidably mounted in translation or clamped on the shaft (A). 7. Valve (1) according to one of the preceding claims, characterized in that the flap (V1 ', V2', V3 ', V4') cooperates, in the closed position, with a seat (0'21 , 0'31.0'41.0'51) present in the associated conduit (C'2, C'3, C'4, C'5), the seat having a bearing (p) at least partially in the form of a truncated cone whose axis (Z) is inclined relative to the central axis (Y) of the shutter in the closed position and / or relative to the axis of the duct. 8. Valve (1) according to one of the preceding claims, characterized in that the angles (I3, y) of the tangent to the path of the flap (V'1) in the closed position of the duct, measured in a plane perpendicular to the axis (X) of the shaft (A) and passing through the center (0) of the flap (V'1) are at least 3 °, and are in particular between 5 and 15 °. 9. Valve (1) according to one of the preceding claims, characterized in that the flap (V1 ', V2', V3 ', V4') is delimited by a frustoconical or toric lateral surface (B'1). 10. Valve (1) according to one of the preceding claims, characterized in that the flap (V1 ', V2', V3 ', V4') is delimited by a lateral surface (B'1) toric and that it rests, in the closed position, on a seat (C'21, C'31, C'41, C'51) present in the associated channel (0'2, 0'3, 4.0'4.0 '5) whose span (pt) is in the form of a truncated cone.35 11. Valve (1) according to one of the preceding claims, characterized in that it is an air intake circuit valve of a heat engine. 12. Intake circuit of a heat engine, characterized in that it comprises at least one valve (1) according to one of the preceding claims.