FR3052527A1 - FLUID FLOW CONTROL VALVE COMPRISING A VALVE BODY - Google Patents

Abstract

The present invention describes a valve (1) for controlling a fluid flow rate, comprising: - a valve body (6), - a fluid circulation duct (2) arranged in the valve body (6), - a rotary shutter (3) disposed in the duct (2), the rotary shutter (3) having a functional fluid passage (4) extending transversely to its axis of rotation, the rotary shutter (3) being configured for controlling the flow of fluid in the conduit, characterized in that the valve (1) has at least one sealing member (5) disposed in the rotary shutter (2) and configured to be pressed against the valve body ( 6) so as to prevent parasitic flow of fluid along a path other than the aforementioned functional passage.

Description

Flow control valve having a valve body

The present invention relates to a control valve of a fluid flow, in particular for the recirculation of exhaust gas on a combustion engine of a motor vehicle.

For example, US Pat. No. 8,862,369 discloses the principle of recirculating part of the exhaust gas from a combustion engine to the engine intake circuit. This technology enables diesel engines to reduce nitrogen oxide emissions. On supercharged spark ignition engines, it reduces fuel consumption.

The recirculated gas flow rate is controlled by a valve. An important characteristic for this type of valve is its sealing, that is to say it is desirable that the valve has a low parasitic leakage level. Another important characteristic is the pressure drop generated by the valve, and it is desirable that this pressure drop be low. It is said that the valve has good permeability.

The principle of this type of valve is to have a movable shutter in a recirculated exhaust gas flow conduit, the position of the movable shutter to control the flow through the valve. There are several technologies, among which we find valve-type shutters, driven by a translational movement, and shutters type shutter or plug, driven by a rotational movement.

This type of valve is capable of operating over a very wide temperature range, between ambient temperature and about 900 ° C. The different parts are thus subject to dimensional variations due to the expansion due to temperature. The design of the valve must therefore be compatible with a significant evolution of the operating clearance between the moving parts of the valve.

Valves having a valve-type movable shutter generally have a low level of leakage because it is possible to ensure a high pressure of the valve on its seat. On the other hand, their permeability is often not very good, because even in the fully open position, the passage section of the duct is restricted by the presence of the valve. This type of valve generally generates a high pressure drop, unfavorable to obtain high flows.

Valves having a shutter-type movable shutter have good permeability because the conduit is not closed when the valve is in the fully open position. On the other hand, their level of internal leakage is high. Indeed, the clearance between the flap and the valve body must be sized for the highest temperatures likely to be encountered. This game therefore creates a high leak under most conditions of current use. The same is true of the bushel type valves.

The object of the invention is to obtain a rotary valve type valve having both a low level of leakage and good permeability, while being compatible with high operating temperatures. For this purpose, the invention proposes a valve for controlling a fluid flow, comprising: a valve body, a fluid circulation duct, arranged in the valve body, a rotary shutter disposed in the duct; rotary shutter comprising a functional passage of fluid extending transversely to its axis of rotation, the rotary shutter being configured to control the flow of fluid in the conduit, characterized in that the valve comprises at least one sealing member disposed in the rotary shutter and configured to be pressed against the valve body to prevent spurious flow of fluid along a path other than the aforementioned functional passage.

Due to the operating clearances, there is free space between the shutter and the valve body, which creates a leakage path. The sealing member disposed in the rotary shutter and pressed against the valve body makes it possible to seal this free space. Thus, the leak is eliminated.

Advantageously, the sealing member is guided by an inner surface for guiding the rotary shutter.

Preferably, the sealing member is movable in the inner guiding surface. The sealing member can move slightly inside the inner guide surface in a translational movement.

More preferably, the sealing member is pressed against the valve body by an elastic return member.

The force applied by the elastic element makes it possible to maintain the sealing member against the valve body even when the operating clearances change, for example due to the change in the temperature of the parts, or because of their wear. . In addition, the dimensional dispersions between the parts, inevitable for mass-produced parts, are compensated since the assembly with a movable sealing member and an elastic return member makes it possible to maintain contact between the sealing member and the valve body in all circumstances. The valve seal is thus improved, regardless of the operating conditions of the valve.

According to an exemplary implementation, the sealing member has an opening facing the fluid flow conduit when the rotary shutter is in a position of maximum opening.

The fluid passing through the flow conduit then passes through the rotary shutter passing through the inner surface of the sealing member.

Advantageously, the fluid can pass only through the functional fluid passage when the rotary shutter is in the open position. The main role of the sealing member is to seal the valve when the rotary shutter is in the closed position. The sealing member also closes the escape path when the valve is in the open position.

Preferably, the surface of the sealing member pressed against the valve body has a shape complementary to that of the inner surface of the valve body receiving the rotary shutter.

The complementary shape of the surfaces in contact allows good contact between the sealing member and the valve body. The amount of gas capable of creeping between the two surfaces is minimized, which ensures a good seal of the valve.

According to one embodiment, the rotary shutter is of generally cylindrical shape. The shutter, just like the valve body receiving the shutter, can thus be manufactured simply.

Preferably, the functional fluid passage of the rotary shutter is cylindrical in shape. The recess allowing the functional passage of fluid can thus be achieved simply, for example by drilling.

Advantageously, the rotary shutter is arranged to prohibit the flow of fluid in the conduit for certain angular positions of the rotary shutter.

By adapting the diameter of the functional fluid passage to the diameter of the valve body conduit and the outer diameter of the rotary shutter, the flow of fluid in the valve is stopped when the shutter is rotated 90 ° from its position. ensuring maximum opening.

According to one embodiment, the inner guide surface in which the sealing member is disposed is cylindrical.

The guide surface can thus be made in a simple manner, for example by turning.

According to one embodiment, the sealing member has a generally hollow cylinder shape. The sealing member can thus be manufactured and assembled in the valve in a simple manner.

Preferably, the inside diameter of the sealing member is equal to the diameter of the fluid circulation duct.

Thus, when the shutter is in the fully open position, the fluid passing through the valve does not encounter a change in section of the duct as it passes from the inside of the circulation duct disposed in the valve body inside the valve. the sealing member. The pressure losses are thus minimized.

According to one embodiment, the surface of the sealing member pressed against the valve body has a generally cylindrical cap shape.

The bearing surface has a substantially constant width. The larger the width, the better the valve seal, but the smaller the passage section. A compromise is therefore to be found according to the conditions of use of the valve, for example according to its maximum operating pressure.

According to one embodiment, the elastic return member is disposed between the sealing member and an element rigidly connected to the rotary shutter. The sealing member and the elastic return member are inserted inside the guide surface of the rotary shutter. The holding member is then inserted into the shutter on the opposite side to the sealing member, and is assembled in the shutter. A fixed bearing surface is thus created for the elastic return member.

According to one embodiment, the elastic return member is a wave spring.

This type of spring is particularly compact.

In a variant, the elastic return member is a helical spring.

This type of spring is inexpensive to produce.

According to one embodiment, the bearing surface of the elastic return member against the sealing member is a shoulder formed on the periphery of the sealing member. The elastic return member is thus disposed between the inner surface for guiding the rotary shutter and the shoulder of the sealing means, which ensures its radial positioning.

Preferably, the ratio between the area of the bearing surface of the elastic return member against the sealing member and the area of the fluid passage surface defined by the passage of the rotary shutter is between 0.1 and 0.3.

This provides a good compromise between loss of passage section for the fluid passing through the valve and space available to dispose the spring.

More preferably, the ratio between the area of the bearing surface of the sealing member against the valve body and the area of the fluid passage surface defined by the passage of the rotary shutter is between 0.2 and 0.3.

This value is a good compromise between improving the seal and reducing the passage section.

According to one embodiment, the axis of the duct portion located upstream of the rotary shutter and the axis of the duct portion located downstream of the rotary shutter are collinear.

Preferably, the axis of the duct portion located upstream of the rotary shutter and the axis of the duct portion located downstream of the rotary shutter coincide.

In this case, the conduit is rectilinear and the fluid undergoes no change of direction in the valve. The pressure losses are thus minimized, the mounting of the valve in the circuit is facilitated.

According to one embodiment, the axis of the duct portion located upstream of the rotary shutter and the axis of the duct portion located downstream of the rotary shutter are concurrent at a point on the axis of rotation of the rotary shutter.

By bringing the outlet duct closer to the inlet duct of the valve, the valve can be more compact than when the ducts are aligned.

According to one embodiment, the sealing member is made of metal, in particular steel, bronze, aluminum.

According to one embodiment, the rotary shutter is made of metal, in particular steel, bronze, aluminum.

The materials of the sealing member and the rotary shutter are selected according to the constraints of the application, such as the temperature and the maximum pressure of the fluid, or its corrosiveness.

According to one embodiment, the valve is arranged to circulate exhaust gas between an exhaust system of a combustion engine and a combustion engine combustion gas intake circuit.

This type of valve is used in a well known manner to reduce the pollutant emissions of combustion engines.

Preferably, the recirculated exhaust gas is taken upstream of a turbocharger of the engine.

More preferably, the recirculated exhaust gas is readmitted into the intake circuit downstream of a supercharger engine.

In this type of architecture conventionally called "high pressure", the valve is subjected to high temperatures and pressures. It is therefore particularly advantageous to have a valve in which the sealing member can compensate for dimensional variations caused by operating temperature variations.

A valve according to the invention can also be used in a "low pressure" type exhaust gas recirculation architecture. "Low pressure" means that exhaust gas sampling in the exhaust line takes place downstream of the turbine, the exhaust gas being recirculated upstream of the compressor. Preferably, the exhaust gas is taken downstream of the pollution control device.

According to one embodiment, the valve comprises a single sealing member disposed in the rotary shutter, the sealing member being configured to be pressed against the valve body, the sealing member being opposite the duct portion located upstream of the rotary shutter when the rotary shutter is in the maximum open position of the valve.

Alternatively, the valve comprises a single sealing member disposed in the rotary shutter, the sealing member being configured to be pressed against the valve body, the sealing member being opposite the portion of the duct located downstream of the rotary shutter when the rotary shutter is in the maximum open position of the valve.

It is possible to arrange the sealing member either upstream of the shutter or downstream of the shutter. The effectiveness for improving the seal is similar.

According to a preferred embodiment, the valve comprises two distinct sealing members, arranged in the rotary shutter, each sealing member being configured to be pressed against the valve body, a sealing member being opposite a portion of duct situated upstream of the rotary shutter when the rotary shutter is in the maximum open position of the valve, and the other sealing member being opposite a portion of duct situated downstream of the shutter; rotary shutter when the rotary shutter is in the maximum open position of the valve.

By using two separate sealing members, the level of leakage is further reduced compared to the configuration with a single sealing member.

Advantageously, the two sealing members are identical.

The valve uses standardized parts to facilitate assembly and to obtain components more economically.

Preferably, the elastic return member is disposed between the two sealing members and simultaneously plates the two sealing members against the valve body.

The same force is applied to the two sealing members, since each end of the elastic return member acts on a sealing member.

According to one embodiment, the elastic return member is a single spring.

The spring is disposed between the two sealing members, the mounting is simple.

According to one embodiment, the elastic return member is a stack of springs.

It is thus possible to have different stiffnesses between the springs, and thus differentiated displacement strokes between the two sealing members. The invention also relates to a combustion engine comprising an exhaust gas recirculation valve as described above. The invention will be better understood on reading the figures.

FIG. 1 schematically represents a combustion engine equipped with an exhaust gas recirculation valve,

FIG. 2 schematically describes a valve according to the state of the art,

Figure 3 is a sectional front view of a valve according to the invention, shown in fully open position.

FIG. 4 is a side sectional view of the valve of FIG. 3,

Figure 5 is a sectional front view of the valve of Figure 3, shown in the closed position.

FIG. 1 shows a combustion engine 20 comprising an exhaust gas recirculation valve 1.

The operation of the combustion engine is conventional: the combustion air is admitted into the intake circuit 21, which comprises a supercharger 25 for increasing the density of the admitted gas mixture.

The fuel is injected into the combustion chambers of the engine 20 by a not shown injection system. After combustion, the exhaust gas is discharged through the exhaust circuit 22. The majority of the exhaust gas passes through the turbine 26 of the turbocharger 24 and causes it to rotate. The energy received by the turbine 26 makes it possible to perform the compressive work of the compressor 25, the turbine 26 and the compressor 25 being integral with the same rotation shaft, the compressor assembly 25 and the turbine 26 forming the turbocharger 24. After being released in the turbine 26, the exhaust gas passes through a pollution control system 27, for removing pollutants present in the exhaust gas, in particular the particles, and are discharged to the outside.

Part of the exhaust gas is recirculated to the intake circuit 21 of the engine 20 via the recirculation circuit 23. The recirculation circuit 23 comprises a heat exchanger 28 and the valve 1.

The valve 1 is arranged to circulate exhaust gas between an exhaust circuit 22 of a combustion engine 20 and an intake circuit 21 of combustion gas of the combustion engine 20. [R28] The recirculation circuit 23 is of the "high pressure" type, that is to say that the recirculated exhaust gas is taken upstream of a turbocharger 26 of the engine 20 [R29], and the exhaust gas recirculated exhaust are readmitted into the intake circuit 21 downstream of a supercharger 25 of the engine 20.

The control of the recirculated exhaust gas flow in the circuit 23 is achieved by varying the gas passage section in the valve 1, by means of a movable shutter. An electric motor controls the position of the shutter, via a control mechanism, not shown. A control unit of the combustion engine, not shown, controls the electric motor of the valve 1 to ensure the flow of recirculated exhaust gas adapted to the operating conditions of the engine 20.

In a "high pressure" type of architecture such as that described in the example described, the valve 1 receives gases at high temperature and under high pressure. Indeed, the gas temperature can reach 900 ° C and the absolute pressure 5 bar.

Figure 2 illustrates a disadvantage of a rotary valve shutter according to the state of the art.

The gases are admitted into the valve 1 through the inlet orifice 16 of the duct 2. The rotary shutter 3 is of generally cylindrical shape. The rotary shutter 3 is disposed in the valve body 6 which has a bore receiving the rotary shutter 3. The control system of the shutter 3 has not been shown. The rotary shutter 3 is arranged to prevent the circulation of fluid in the duct 2 for certain angular positions of the rotary shutter 3. In these positions, the duct 2 is closed by the shutter 3, as is the case on Figure 2. The shutter 3 comprises a functional passage 4 for the flow of gas in the valve when the passage is aligned, partially or totally, with the inlet duct and the outlet duct.

In the example shown, the functional fluid passage 4 of the rotary shutter 3 is of cylindrical shape.

Sufficient clearance must be provided between the rotary shutter 3 and the valve body 6 to absorb the differential expansions caused by the temperature difference between the rotary shutter 3 and the housing in which the shutter pivots. Because of this game, there is a leakage path between the shutter 3 and the valve body, which makes that there is a leakage rate F even when the rotary shutter 3 is in the closed position, as shown in FIG. FIG. 2. The gases forming the leakage flow F exit from the valve through the outlet orifice 17 of the duct 2. The object of the invention is to eliminate this leakage flow rate.

Figure 3 shows a schematic valve according to the invention.

The valve 1 for controlling a fluid flow comprises: a valve body 6, a fluid circulation duct 2, arranged in the valve body 6, a rotary shutter 3 disposed in the duct 2, the rotary shutter 3 having a functional fluid passage 4 extending transversely to its axis of rotation, the rotary shutter 3 being configured to control the flow of fluid in the conduit, and is characterized in that the valve 1 comprises at least one valve member. sealing 5 disposed in the rotary shutter 3 and configured to be pressed against the valve body 6 so as to prevent spurious flow of fluid along a path other than the aforementioned functional passage. The sealing member 5 is pressed against the valve body at the bearing surface 12.

The leakage path of a valve according to the state of the art is thus closed. The sealing member 5 is pressed against the valve body 6 by an elastic return member 7. The sealing member 5 is guided by an inner surface 18 for guiding the rotary shutter 3. 5 is movable in the inner surface 18 of guiding. The sealing member 5 can move slightly inside the rotary shutter, in a translational movement. When, during the use of the valve, the clearance between the rotary shutter 3 and the valve body 6 increases or decreases slightly, under the effect of the temperature of the gases passing through the valve 1, the force applied by the resilient return member 7 keeps the sealing member 5 against the valve body 6. Indeed, when the game increases, the force applied by the elastic return member 7 pushes the sealing member 5 and keeps it pressed against the valve body 6. When the play decreases, the sealing member 5 fits slightly inside the guide surface 18 of the rotary shutter 3, by pushing the elastic return member 7.

In the same way, the dimensional dispersions between the parts produced in series are compensated, since the assembly with a movable sealing member 5 and an elastic return member 7 makes it possible to ensure the contact between the sealing member 5 and the valve body 6 regardless of the clearance value. Thus, the seal of the valve 1 is improved, whatever the operating conditions, throughout the lifetime of the valve.

The inner guide surface 18 in which the sealing member 5 is disposed is cylindrical. The inner guide surface 18 can thus be made simply, for example by turning. The sealing member 5 has a generally hollow cylinder shape. The sealing member 5 can thus be obtained simply, in particular by turning to obtain the external shape, a bore then making it possible to obtain the inner surface in which the recirculated exhaust gas circulates.

In the example shown in FIGS. 3 to 5, the valve 1 comprises two distinct sealing members 5, 5 'arranged in the rotary shutter 3, each sealing member 5, 5' being configured to be pressed against the valve body 6, a sealing member 5 being opposite a conduit portion 14 located upstream of the rotary shutter 3 when the rotary shutter 3 is in the maximum open position of the valve, and another sealing member 5 'facing a portion of duct 15 located downstream of the rotary shutter 3 when the rotary shutter 3 is in the maximum open position of the valve.

In the example shown, the two sealing members are identical. Each sealing member 5, 5 'is in contact with the valve body 6 at a contact surface 12, 12'. The elastic return member 7 is disposed between the two sealing members 5, 5 'and simultaneously plates the two sealing members against the valve body 6.

The same force is applied to the two sealing members, since each end of the elastic return member acts on a sealing member.

In the example of Figures 3 to 5, the elastic return member is a single spring.

In this example, the elastic return member 7 is a wave spring. This type of spring is very compact, which promotes obtaining a high passage section for a given size. The sealing member 5 comprises an opening facing the fluid circulation duct 2 when the rotary shutter 3 is in a position of maximum opening. It is the same for the second sealing member 5 '.

More precisely, and as illustrated in FIGS. 3 and 4, the inside diameter of the sealing member 5, 5 'is equal to the diameter of the fluid circulation duct 2. [R14] In the fully open position of the valve 1, the fluid flow therefore does not encounter a change of section at the passage passing from the conduit 2 to the inner surface of the closure member 5, the inlet side of the valve, or passing from the closure member 5 'to the conduit 2, the output side of the valve. The pressure drops generated by the valve 1 are thus minimized.

The fluid can pass only through the fluid functional passage 4 when the rotary shutter 3 is in the open position.

The surface 12 of the sealing member 5 pressed against the valve body 6 has a shape complementary to that of the internal surface of the valve body 6 receiving the rotary shutter 3. [R7] It is the same for the surface 12 'of the sealing member 5'.

The surface 12 of the sealing member 5 pressed against the valve body 6 has a generally cylindrical cap shape.

Preferably, the ratio between the area of the bearing surface 13 of the elastic return member 7 against the sealing member 5 and the area of the fluid passage surface delimited by the passage 4 of the rotary shutter 3 is between 0.2 and 1.5. By this ratio is meant the quotient of the area of the bearing surface 13 of the elastic element 7 against the sealing member 5 and the area of the fluid passage surface provided by the passage 4 of the rotary shutter 3.

This gives a good compromise between the loss of passage section for the fluid passing through the valve and the space available to dispose the spring.

More preferably, the ratio between the area of the bearing surface 12 of the sealing member 5 against the valve body 6 and the area of the fluid passage surface delimited by the passage 4 of the rotary shutter 3 is between 0.3 and 1.9. As before, this ratio is calculated as the quotient of the area of the bearing surface 12 of the sealing member 5 against the valve body 6 and the area of the fluid passage surface offered by the passage 4 of the rotary shutter 3.

This value is a good compromise between improving the seal and reducing the passage section.

According to one embodiment, the axis of the duct portion 14 located upstream of the rotary shutter 3 and the axis of the duct portion 15 located downstream of the rotary shutter 3 are collinear.

In the example shown, the axis of the duct portion 14 located upstream of the rotary shutter 3 and the axis of the duct portion 15 located downstream of the rotary shutter 3 coincide. Thus, the flow conduit is rectilinear and the fluid undergoes no change of direction in the valve. The pressure losses are thus minimized, moreover the mounting of the valve in the recirculation circuit 23 is facilitated.

According to one embodiment, the sealing member 5, 5 'is made of metal, in particular steel, bronze, aluminum.

According to one embodiment, the rotary shutter 3 is made of metal, in particular steel, bronze, aluminum.

The materials of the sealing member and the rotary shutter are selected according to the constraints of the application, such as the temperature and the maximum pressure of the fluid, or its corrosiveness.

According to embodiments not shown, the described valve may also comprise one or more of the following characteristics, considered individually or in combination with one another:

The bearing surface 13 of the elastic return member 7 against the sealing member 5 is a shoulder formed on the periphery of the sealing member 5. The elastic return member is thus disposed between the surface internal guide of the rotary shutter and the shoulder of the sealing means, which ensures its radial positioning. The elastic return member 7 is disposed between the sealing member 5 and an element rigidly connected to the rotary shutter 3. The resilient return member 7 is a helical spring.

This type of spring has good reliability while being inexpensive. The axis of the duct portion 14 located upstream of the rotary shutter 3 and the axis of the duct portion 15 located downstream of the rotary shutter 3 are concurrent at a point situated on the axis of rotation of the the rotary shutter 3.

By thus bringing the outlet duct of the inlet duct of the valve closer, the valve can be more compact.

The valve 1 comprises a single sealing member 5 disposed in the rotary shutter 3, the sealing member 5 being configured to be pressed against the valve body 6, the sealing member being opposite the portion duct located upstream of the rotary shutter 3 when the rotary shutter 3 is in the maximum open position of the valve.

Alternatively, the valve 1 comprises a single sealing member 5 'disposed in the rotary shutter 3, the sealing member 5' being configured to be pressed against the valve body 6, the sealing member being in position. view of the duct portion located downstream of the rotary shutter 3 when the rotary shutter 3 is in the maximum open position of the valve.

The construction of the valve is simplified using a single sealing means. It is possible to arrange the sealing member either upstream of the shutter or downstream of the shutter. The elastic return member 7 is a stack of springs. The springs are against each other. The elastic return member 7 comprises a plurality of springs, the springs not being in contact with each other. In this case applying to the configuration with two sealing members, each spring bears on a fixed part of the rotary shutter 3, for example a shoulder.

It is thus possible to have different stiffness between the springs. The contact pressure between each sealing member and the valve body can thus be differentiated.

The valve of the example described is an exhaust gas recirculation valve. The same principle can be applied to other types of valves for combustion engines. The sealing member may be of low friction coefficient of friction polymer, especially PTFE.

For different applications for which the thermal stresses are not severe, the sealing member may be made of plastic. The invention is not limited to the embodiments described and illustrated, which have been given by way of example. On the contrary, other applications are also possible without departing from the scope of the invention.

Claims (10)

A fluid flow control valve (1), comprising: a valve body (6), a fluid circulation duct (2) arranged in the valve body (6), a rotary shutter (3). ) disposed in the duct (2), the rotary shutter (3) having a functional fluid passage (4) extending transversely to its axis of rotation, the rotary shutter (3) being configured to control the flow of fluid in the conduit, characterized in that the valve (1) has at least one sealing member (5) disposed in the rotary shutter (3) and configured to be pressed against the valve body (6) so as to prevent a parasitic flow of fluid along a path other than the aforementioned functional passage. 2. Valve according to the preceding claim, wherein the sealing member (5) is guided by an inner surface (18) for guiding the rotary shutter (3). 3. Valve according to one of the preceding claims, wherein the sealing member (5) is pressed against the valve body (6) by an elastic return member (7). [R4] 4. Valve according to one of the preceding claims, wherein a surface (12) of the sealing member (5) pressed against the valve body (6) has a shape complementary to that of an internal surface of the body valve (6) receiving the rotary shutter (3). 5. Valve according to one of claims 2 to 4, wherein the inner surface (18) of guide in which is disposed the sealing member (5) is cylindrical. 6. Valve according to one of claims 3 to 5, wherein the elastic return member (7) is a wave spring. 7. Valve according to one of the preceding claims, arranged to circulate exhaust gas between an exhaust system (22) of a combustion engine (20) and an intake circuit (21) of oxidizing gas of the combustion engine (20). Valve according to one of the preceding claims, according to which the valve (1) comprises two distinct sealing members (5, 5 ') arranged in the rotary shutter (3), each sealing member (5, 5 ') being configured to be pressed against the valve body (6), a sealing member being opposite a duct portion (14) located upstream of the rotary shutter (3) when the rotary shutter (3) is in the maximum open position of the valve, and the other sealing member being opposite a portion of duct (15) located downstream of the rotary shutter (3) when the rotary shutter (3) is in the maximum open position of the valve. 9. Valve according to the preceding claim, wherein the resilient return member is disposed between the two sealing members (5,5 ') and simultaneously plate the two sealing members (5, 5') against the body of valve (6). 10. A combustion engine comprising an exhaust gas recirculation valve according to one of the preceding claims.