VALVE, IN PARTICULAR FOR AN INTERNAL COMBUSTION ENGINE

Abstract

A valve (1), in particular for a combustion engine, comprising:—a body (2) in which the following are provided: a housing (8) in which at least one bearing is arranged, and a conduit (3) designed to be traversed by a fluid, and—a shutter (5) mounted pivoting in the body (2) by a pin (7) received with radial clearance in the bearing, the shutter (5) pivoting between:—an open position, and—a closed position in which it comes into contact with the body (2) via a first contact area of the shutter located on a first side of the pin (7) and via a second contact area of the shutter located on a second side of the pin (7) opposite said first side, the switching of the shutter (5) from the open position to the closed position being accompanied by a radial movement of the pin (7) in the bearing.

Description

The present invention concerns a valve, in particular for an internal combustion engine.

The invention in particular applies when the internal combustion engine is used for the propulsion of a vehicle, for example a motor vehicle. It may be an engine the fuel of which is petrol or diesel. The valve may be integrated into the air circuit of the internal combustion engine.

In the context of the invention, the “internal combustion engine air circuit” means the circuit between the admission inlet and the exhaust outlet of the internal combustion engine. The valve may be in the admission circuit, the exhaust circuit, or a recirculation loop through which exhaust gas recirculation (EGR) gases pass.

In the case of a valve including:

• • a body including a duct in which a fluid flows, and
  • a shutter mounted to be mobile in the body between an open position and a closed position in which it has to block the duct,
    there are problems of the valve leaking when the shutter is in the closed position. To solve these problems, it is known to use a seal that is disposed between the body and the shutter when the latter is in the closed position. However, a seal of this kind is liable to expand because of the high temperatures that can be reached in its environment.

Another solution to this problem linked to the use of a seal is to bring the shutter directly into contact with the body when the shutter is in the closed position. However, a dimensional constraint between the shutter and the part of the duct in which it moves must be complied with to prevent the shutter from being wedged against the wall of said part of the duct before reaching the closed position, as is described hereinafter with references to FIGS. 24 and 25.

In those figures, the body 102 has a sealing plane P coming into contact with a sealing plane P′ of the shutter 105 when the shutter is in the closed position to block the duct 103 in the body 102. Because of the rigid nature of the contacts between the shutter and the body, it is found that the shutter 105 is prevented from being wedged against the wall of the body 102 if the distance Dv measured between the center of the pin 107 enabling the shutter 105 to pivot in the body 102 and the sealing plane P′ of the shutter 105 is less than or equal to the distance Dc measured between the center of the housing 108 of the body 102 in which the pin 107 is received and the sealing plane P of the body 102.

This dimensional constraint must further be weighted to allow for inaccuracies in respect of the dimensions of the various components of the valve during manufacture thereof. Because of this weighting, there may be relatively large empty sections between the body and the shutter when the shutter is in the closed position, these empty sections, also known as “leakage sections”, potentially causing leaks greater than what can be tolerated when the valve is in the closed position.

There exists a requirement for a valve that is relatively simple to manufacture and effectively overcomes the disadvantages referred to above.

An object of the invention is to address this requirement and, in one of its aspects, it does so by means of a valve, in particular for an internal combustion engine, comprising:

• • a body including: a housing in which is disposed at least one bearing and a duct adapted to have a fluid pass through it, and
  • a shutter mounted to pivot in the body by means of a pin received with radial play in the bearing,
    the shutter pivoting between:
  • an open position, and
  • a closed position in which it comes into contact with the body in a first contact area of the shutter on a first side of the pin and in a second contact area of the shutter on a second side of the pin opposite said first side,
    the passage of the shutter from the open position to the closed position being accompanied by radial movement of the pin in the bearing.

The above valve makes it possible to prevent the shutter from being wedged against the wall of the duct when the shutter goes to the closed position without it being necessary to comply with any excessive dimensional constraint between the shutter and the part of the duct in which it moves.

This dimensional constraint is reduced thanks to the use of the play of the bearing(s), which constitutes an adjustment variable with regard to inaccuracies in the dimensions of the various components of the valve during manufacture thereof.

The shutter is preferably not directly in contact with the body when it is in the open position.

When it moves, the shutter may be in a single closed position, in which it comes into contact with the body. The valve may be a valve in the admission circuit of the internal combustion engine, in the exhaust circuit of the internal combustion engine, or in an exhaust gas recirculation loop enabling the latter gases to be re-injected into the admission side of the internal combustion engine. This recirculation loop may be a “low-pressure” loop or a “high-pressure” loop.

The valve is in particular a so-called “two-port” valve.

Alternatively, the valve may be a so-called “three-port” valve. The valve may then be at the inlet of the recirculation loop, that is to say at the place in the exhaust circuit at which the recirculation loop starts. The so-called “three-port” valve may alternatively be at the outlet of the recirculation loop, that is to say at the place in the admission circuit where the exhaust gases are re-injected into the admission side.

The valve may therefore be at most a three-port valve.

The closed position, in which the shutter blocks the duct, and the open position may each be an extreme position for the pivoting of the shutter. In other words, the pivoting of the shutter between the open position and the closed position defines the maximum amplitude of the movement in rotation of the shutter.

There is advantageously no flexible element of the valve between the shutter and the body when the shutter is in the closed position. Here “flexible” is used in contrast to “rigid”, the body and the shutter then being rigid.

A flexible element of this kind is a seal, for example. The shutter and the pin may be connected by a support extending along at least a portion of the pin. The pin and the shutter may be in different planes.

The valve therefore has a pin offset relative to the shutter, in contrast to valves in which the pin and the shutter are in the same plane.

Alternatively, the pin and the shutter may be in the same plane.

The body may have a sealing plane of the body coming into contact with the first and/or second contact area of the shutter when the shutter is in the closed position and the first and/or the second contact area of the shutter may be in a sealing plane of the shutter.

The first contact area of the shutter may be in a sealing plane of the shutter other than a plane intersecting the axis.

The second contact area of the shutter may be in another sealing plane of the shutter other than a plane intersecting the axis.

When the shutter is in the closed position, the sealing plane of the body and the sealing plane of the shutter have at least one point of contact. The radial play of the bearing(s) may distance a portion of the shutter from the sealing plane of the body when the shutter goes to the closed position.

The distance between the center of the housing and the sealing plane of the body may be greater than the distance between the center of the pin and the sealing plane of the shutter. This dimensional constraint, which is generally imposed, makes it possible to prevent the shutter from being wedged against the wall of the duct when the shutter goes to the closed position. If this constraint is complied with, no play in the bearing is necessary to prevent the shutter from being wedged against the wall of the duct. The second area of contact of the shutter against the body can make it possible to prevent excessive movement of the pin in the bearing and thus to prevent excessively large leakage sections existing when the shutter is in the closed position. This therefore reduces the use of the radial play available in the bearing(s), given that the movement of the shutter because this play to prevent wedging is then not necessary.

Alternatively, the distance between the center of the housing and the sealing plane of the body may be less than the distance between the center of the pin and the sealing plane of the shutter. This situation can arise even though an attempt has been made to comply with the above dimensional constraint, because of inaccuracies in the dimensions of the components of the valve during manufacture thereof. If no play of the bearing(s) is used, this situation leads to wedging of the shutter against the wall of the duct when the shutter goes to the closed position, which normally prevents the use of any such valve. Using the play in the bearing(s) makes it possible to revert to the previous situation in which there is no wedging.

Thus the invention can make it possible nevertheless to use valves in which, for reasons of inaccuracies in the dimensions of the components of the valve during manufacture thereof, the above dimensional constraint between the shutter and the wall of the body in which it moves are not complied with.

The play in the bearing(s) may be sized to be greater than or equal to a predefined overall inaccuracy for the shutter and the part of the duct in which the shutter moves, this predefined overall inaccuracy resulting in particular from the linear combination of predefined individual inaccuracy for each side of the shutter and the part of the duct in which the shutter moves. Each predefined overall inaccuracy is for example fixed as a function of feedback in respect of the technique used to manufacture the corresponding component of the valve.

The predefined overall inaccuracy may be obtained by adding the predefined individual inaccuracies for the following dimensions:

• • distance between the center of the housing and the sealing plane of the body,
  • distance between the center of the pin and the sealing plane of the shutter,
  • thickness of the shutter,
  • height of a groove in the duct, one part of the shutter in which the second area of contact is situated in the closed position moving in this groove when the shutter goes from the open position to the closed position.

In accordance with a first embodiment of the invention, the first and/or second contact area of the shutter forms a line contact with the body when the shutter is in the closed position.

Each contact area of the shutter may form a line contact with the body when the shutter is in the closed position.

In accordance with this first embodiment of the invention, only the first contact area of the shutter can come into contact with the sealing plane of the body when the shutter is in the closed position. The second contact area of the shutter may be in another plane of the shutter and come into contact with the body elsewhere than in the sealing plane of the body when the shutter is in the closed position. The sealing plane of the shutter and this other plane of the shutter may then be parts of opposite faces of the shutter, the latter in particular taking the form of a plate.

The shutter may have a rectangular shape in section, the first contact area and the second contact area being on opposite sides of the shutter.

Alternatively, the shutter may have a half-moon shape in section the diameter of which is extended by a rectangle and the first area of contact may be on the circle of the half-moon and the second contact area carried by the side of the rectangle opposite the side of the rectangle coinciding with the diameter of the half-moon.

When the part of the shutter carrying the second contact area in the closed position moves in a groove in the body and forming part of the duct, the second contact area can then contact the bottom of the groove formed by said other plane.

In accordance with a second embodiment of the invention, the first and/or second contact area of the shutter may form a plane contact with the sealing plane of the body when the shutter is in the closed position.

For example, each contact area of the shutter forms a plane contact with the sealing plane of the body when the shutter is in the closed position.

The first and second contact areas of the shutter may be in the sealing plane of the shutter and each of said contact areas of the shutter then contacts the sealing plane of the body when the shutter is in the closed position. The shutter may then be a self-centering shutter, by virtue of the fact that the contacts between the shutter and the body occur in a single plane when the shutter is in the closed position and radial play exists in the bearing(s). With such a valve, when the shutter is in the closed position, the contacts between the shutter and the body can enable immobilization of the pin without the latter being in contact with the bearing(s).

The sealing plane of the shutter may a plane other than a plane intersecting the pin.

In accordance with this second embodiment of the invention, the first contact area of the shutter may be carried by a first part of the shutter and be part of the upper face of said first part and the second contact area of the shutter may be carried by a second part of the shutter and be part of the lower face of said second part. In other words, in accordance with this second embodiment of the invention, the first and second contact areas may be parts of opposite faces of the shutter whilst being in the same plane.

Each of the first and second parts may be a separate part, said parts being rigidly coupled to each other to form the shutter. Each of these parts is a plate, for example. Said parts are in particular rigidly coupled to each other at the level of the sealing plane of the shutter.

In accordance with this second embodiment of the invention, the part of the duct in which the shutter moves may be formed in two parts of the body rigidly coupled to each other at the level of the sealing plane of the body. Part of the sealing plane of the body may be defined by the upper face of one of these parts of the body, which then comes into contact with the part of the lower face of the second part of the shutter forming the second contact area when the shutter is in the closed position whereas another part of the sealing plane of the body may be defined by the lower face of another part of the body which then comes into contact with the part of the upper face of the first part of the shutter forming the first contact area when the shutter is in the closed position.

In accordance with the second embodiment of the invention, the length of the second part of the shutter measured along the pin may be less than the length of the first part of the shutter measured along the pin. The shutter is then formed by two parts of different length and the length of the first part can be such that in the closed position no leakage occurs at the level of this first part and only the second part causes leaks.

The invention may be better understood by reading the following description of nonlimiting embodiments thereof and examining the appended drawings, in which:

FIGS. 1 to 11 relate to a valve in accordance with a first embodiment of the invention, FIGS. 1 and 2 representing the valve in elevation, FIG. 3 representing the shutter and the pin separately, FIG. 4 being a plan view of the valve from FIG. 1, FIGS. 5 to 7 representing in section taken along the line A-A a first valve similar to that from FIG. 4, FIGS. 8 to 10 representing in section taken along the line A-A a second valve similar to that from FIG. 4, and FIG. 11 diagrammatically representing a valve in accordance with the first embodiment of the invention when it is of the “three-port” type,

FIGS. 12 to 23 relate to a valve in accordance with a second embodiment of the invention, FIGS. 12 and 13 representing the valve in elevation, FIG. 14 representing the shutter and the pin separately, FIG. 15 being a plan view of the valve from FIG. 12, FIGS. 16 to 18 representing in section taken along the lines A-A, B-B and C-C a first valve similar to that from FIG. 15, FIGS. 19 to 21 representing in section taken along the lines A-A, B-B and C-C a second valve similar to that from FIG. 15, FIG. 22 representing the valve from FIG. 15 in an exaggerated manner,

FIG. 23 diagrammatically representing a valve in accordance with the second embodiment of the invention when it is of the “three-port” type, and

FIGS. 24 and 25 have already been described.

There has been represented in FIG. 1 a valve 1 covered by the invention. In this figure the valve 1 is a so-called “two-port” valve but the invention is not limited thereto, as emerges hereinafter.

The valve 1 that is to be described is a valve used in an air circuit of an internal combustion engine, used for example to propel a motor vehicle.

The valve 1 includes a body 2, for example made from aluminum, steel, plastic or stainless steel, in which is formed a duct 3. This is for example an admission duct, an exhaust duct or a duct forming an exhaust gas recirculation (EGR) loop, which can be a high-pressure loop or a low-pressure loop. The body 2 of the valve may be made by assembling two parts 2a and 2b, these two parts being in contact on a plane P of which one wall defines a part of the duct 3, as emerges hereinafter. The plane P is referred to as the “sealing plane” of the body 2 hereinafter. The part 2b has not represented in FIG. 2.

In the example considered gases that can reach a high temperature, for example up to 700° C., pass through the duct 3.

As represented in FIGS. 1 and 2, the valve 1 includes a shutter 5 disposed in the body and mounted to pivot thanks to a pin 7 received in a housing 8 of the body 2 by means of one or more bearings that are not represented. The pin 7 extends in a direction X and the bearing(s) have radial play in the direction X allowing the pin 7 to move in the bearing and in the housing 8 perpendicularly to the direction X. FIG. 3 represents the shutter 5 and the pin 7 separately. As can be seen in FIG. 3, the shutter can take the form of a cylinder of circular cross section. In the example described a support 9 extending radially relative to the pin 7 connects the pin 7 and the shutter 5.

In the FIG. 3 example, the shutter 5 is globally plane and perpendicular to the direction of the support 9.

As emerges hereinafter, the shutter 5 has two areas 11 and 12 of contact with the body 2 when it is the closed position. The first contact area 11 is on a first side of the pin 7, that is to say a first side of the support 9 here and the second contact area 12 is on a second side of the pin 7, that is to say a second side of the support 9 here. The second contact area 12 is carried by a portion of the shutter moving in a groove 13 formed in the duct 3. Here the second contact area 12 comes into contact with the bottom of the groove 13.

The distance between the center of the housing 8 and the sealing plane P of the body 2 is designated “Dc”. In the example shown in FIGS. 1 to 11, the upper face of the shutter 5 defines a joint plane P′ of the shutter 5, as explained hereinafter, and the distance between the center of the pin 7 and this plane P is designated “Dv”.

In the example shown in FIGS. 5 to 7, the distance Dc is less than Dv, that is to say the sealing plane P′ of the shutter is farther from the sealing plane P of the body from the pin 7. In the prior art, such a configuration, which can be explained by the margins of error in respect of the dimensions of the various components of the valve 1 during manufacture thereof, prevents the shutter 5 from reaching its closed position, the shutter being wedged against the wall of the duct 3 before it can reach the closed position.

In FIG. 5, the shutter 5 is still in the open position and gases can circulate in the duct 3 and through the valve 1. Here the shutter 5 is not in contact with the body 2, neither the first contact area 11 nor the second contact area 12 coming into contact with the body 2.

In FIG. 6, the shutter 5 is moving toward the closed position by pivoting of the pin 7 in the housing 8. Contact is then established between the shutter 5 and the body 2 of the valve 1.

As can be seen in FIG. 7, in contrast to the prior art valves, the fact that the sealing plane P′ of the shutter 5 is farther than the sealing plane P of the body 2 from the pin 7 does not prevent the shutter 5 from reaching a closed position in which it comes into contact with the body 2 in two separate areas 11 and 12. In fact, as represented in FIG. 7, because of the closing torque applied to the shutter by an actuator that is not represented, the pin 7 moves radially relative to the direction X in the housing 8, with the result that the positions relative to the pin 7 of the sealing plane P′ of the shutter 5 and the sealing plane P of the body 2 are modified and the contact that can be seen in FIG. 6 between the shutter 5 and the body does not prevent the shutter 5 from continuing to move toward the closed position.

In this example the shutter comes into contact with two separate walls of the duct 3. In this first embodiment of the invention only the first contact area 11 is in the sealing plane P′ of the shutter 5 and in this embodiment only this first contact area 11 comes into contact with the sealing plane P of the body 2.

In this embodiment there is therefore only one area of contact between the sealing plane P of the body 2 and the sealing plane P′ of the shutter 5.

Here the second contact area 12 is in a plane parallel to the sealing plane P′ of the shutter 5 and defining the face of the shutter 5 opposite that formed by the sealing plane P′.

The play in the bearing(s) making it possible to prevent the shutter 5 from being wedged against the wall of the body 2 when the shutter 5 goes to the closed position is determined taking into account the inaccuracies in respect of the following dimensions, for example:

• • distance Dv,
  • distance Dc,
  • thickness e of the shutter 5 in the second contact area 12,
  • height h of the groove 13.

In this example the play in the bearings is chosen to prevent wedging of the shutter 5 in the following extreme cases because of the dimensional inaccuracies:

• • (i) maximum Dc, minimum Dv, maximum h and minimum e, corresponding to potential interference at the top of the bearings,
  • (ii) minimum Dc, maximum Dv, minimum h and maximum e, corresponding to potential interference at the bottom of the bearings.

Four dimensions may be taken into account for the distance Dv, i.e. four individual levels of inaccuracy to be defined:

• • the straightness of the pin 7, for which an individual level of inaccuracy of 0.02 mm in respect of the diameter of the pin 7 is set, for example,
  • the position of the driving flats on the pin 7, for which an individual level of inaccuracy of 0.1 mm is set, for example,
  • the position of the driving flats on the pin 5, for which an individual level of inaccuracy of 0.04 mm is set, for example, and
  • the position of the sealing plane P′ of the shutter 5, for which an individual level of inaccuracy of 0.04 mm is set, for example.

Two dimensions are to be taken into account for the distance Dc, i.e. two individual levels of inaccuracy to be defined:

• • the position of the sealing plane P of the body 2, for which an individual level of inaccuracy of 0.1 mm is set, for example, and
  • the coaxial relationship of the bearings, for which a level of inaccuracy of 0.04 mm in respect of the diameter of the bearings is set, for example.

There is therefore a variation of ±0.10 mm in Dv and ±0.07 mm in Dc.

In the extreme case (i), the compensation of play available in the upward direction must be at least (+0.07)−(−0.1)=0.17 mm in the example considered.

In the extreme case (ii), the compensation of play available in the downward direction must be at least (−0.07)−(+0.1)=−0.17 mm.

A predefined overall error margin of 0.34 mm is therefore obtained, as a result of which the bearings are sized so that each of them offers at least 0.34/2 mm, i.e. 0.17 mm, of radial play in this example.

FIGS. 8 to 10 also represent the valve 1 when the shutter 5 goes from the open position to the closed position. In contrast to the example that has just been described, the distance Dc is greater than the distance Dv, that is to say the sealing plane P′ of the shutter is nearer the pin 7 than the sealing plane P of the body. In this case, in contrast to the previous case, it is not necessary to modify the relative positions of the sealing plane P′ of the shutter 5 and the sealing plane P of the body 2 relative to the pin 7 to enable the shutter 5 to reach the closed position.

The second contact area 12, on the side of the pin 7 opposite the side bearing the first contact area 11, makes it possible to prevent excessive radial movement of the pin 7 in the housing 8. The second contact area in fact comes to bear against the bottom of the groove 13, preventing further movement of the pin 7 in the bearing because of the closing torque applied by the valve actuator. This therefore prevents serious leaks when the shutter 5 is in the closed position because of this movement linked to the existence of the radial play in the bearings.

In accordance with this first embodiment of the invention, when the shutter is in the closed position the shutter 5 forms a line contact with the body 2 in the first contact area 11 and in the second contact area 12.

The embodiments shown FIGS. 1 to 10 relate to a so-called “two-port” valve. However, the first embodiment of the invention also covers so-called “three-port” valves, as FIG. 11 shows. In this figure, the duct 3 comprises an inlet 20, a first outlet 21 and a second outlet 22. For example, the first outlet 21 allows the gases circulating in the exhaust circuit to continue their path in the latter and the second outlet 22 opens into a recirculation loop to the admission side of the engine. In this example, the shutter 5 of the valve 1 from FIGS. 1 to 10 has an extension 24 extending beyond the part of the shutter 5 including the second area 12, so that the latter is disposed between said extension 24 and the part of the shutter including the first area 11.

In FIG. 11, the shutter 5 is in a position in which the exhaust gases recirculate in the EGR loop. The extension 24 partially blocks the passage toward the first outlet 21, in order to create a back-pressure for maintaining sufficient pressure on the upstream side of the valve 5 to enable a high flow rate toward the second outlet 22.

A valve 1 in accordance with a second embodiment of the invention is described next with reference to FIGS. 12 to 22.

FIGS. 12 to 15 are similar to FIGS. 1 to 4. In accordance with this second embodiment, the shutter 5 comprises two portions 30 and 31 formed by separate parts fastened together. Each of these parts is in the form of a plate and the upper face 32 of the plate 30 lies against the lower face 33 of the plate 31 without these plates 30 and 31 being exactly superposed. In this example, the upper face 32 of the plate 30 and the lower face 33 of the plate 31 are coplanar and be in the sealing plane P′ of the shutter 5. The sealing plane P of the body 2 is similar to that described with reference to the first embodiment of the invention. Screws 35 are used to fix the plate 31 to the plate 30, for example.

In the embodiment represented the plate 30 is nearer the pin 7 than the plate 31 and here the plate 30 is connected to the support 9.

Here the upper face of the shutter 5 is defined by the portion of the upper face 32 of the plate 30 not facing the plate 31 and by the upper face of the plate 31 and the lower face of the shutter 5 is defined by the lower face of the plate 30 and by the portion of the lower face 33 of the plate 31 not facing the plate 30.

Still in this embodiment, and as can be seen in FIG. 14, the length l1 of the plate 30 as measured in the direction X is greater than the length l2 of the plate 31.

In accordance with this second embodiment of the invention, the two parts 2a and 2b of the body are rigidly coupled to each other at the level of the sealing plane P of the body 2.

FIGS. 16 through 18 each represent three views in section of a position of the shutter 5 when Dv is greater than Dc.

In FIG. 16, the shutter 5 is in the open position and is not in contact with the body 2. In FIG. 17, the shutter 5 is going from the open position toward the closed position and the upper face 32 of the plate 31 is on the point of coming into contact with the sealing plane P of the body 2, this contact causing wedging of the shutter 5 in the duct 3 in the prior art.

As can be seen in FIG. 17, thanks to the radial play in the bearing(s), the pin 7 is able to move radially, allowing the plate 30 to move away from the sealing plane P of the body 2. The shutter 5 can continue its movement until it reaches the closed position in which it comes into contact with the sealing plane P of the body 2 via the first area 11 and the second area 12. Here the first area 11 is on the upper face 32 of the plate 30 and the second area 12 is on the lower face 33 of the plate 31. The first area 11 and the second area 12 are therefore in the same plane, namely the sealing plane P′ of the shutter 5. Here the contact between the shutter 5 and the body 2 via the first and second areas 11 and 12 is plane, occurring exclusively between the respective sealing planes P and P′.

For example, the play in the bearing(s) for preventing the shutter 5 from being wedged against the wall of the body 2 when the shutter 5 goes to the closed position is determined in accordance with this second embodiment of the invention by taking into account the inaccuracies in respect of the following dimensions:

• • distance Dv, and
  • distance Dc.

In this embodiment the play in the bearings is chosen so that it prevents wedging of the shutter 5 in the following extreme cases resulting from dimensional inaccuracies:

• • (i) maximum Dc, minimum Dv, corresponding to potential interference at the top of the bearings,
  • (ii) minimum Dc, maximum Dv, corresponding to potential interference at the bottom of the bearings.

Four dimensions are to be taken into account for the distance Dv, i.e. four individual levels of inaccuracy to be defined:

• • the straightness of the axis 7, for which an individual level of inaccuracy of 0.02 mm in respect of the diameter of the pin 7 is set, for example,
  • the position of the driving flats on the pin 7, for which an individual level of inaccuracy of 0.1 mm is set, for example,
  • the position of the driving flats on the shutter 5, for which an individual level of inaccuracy of 0.04 mm is set, for example, and
  • the position of the sealing plane P′ of the shutter 5, for which an individual level of inaccuracy of 0.04 mm is set, for example.

Two dimensions are to be taken into account for the distance Dc, i.e. two individual levels of inaccuracy to be defined:

• • the position of the sealing plane P of the body 2, for which an individual level of inaccuracy of 0.1 mm is set, for example, and
  • the coaxial relationship of the bearings, for which a level of inaccuracy of 0.04 mm in respect of the diameter of the bearings is set, for example.

There is therefore a variation of ±0.1 mm in Dv and ±0.07 mm in Dc.

In the extreme case (i), the compensation of play available in the upward direction must be at least (+0.07)−(−0.1)=0.17 mm in the example considered.

In the extreme case (ii), the compensation of play available in the downward direction must be at least (−0.07)−(+0.1)=−0.17 mm.

There is therefore obtained a predefined overall error margin of 0.34 mm, which means that the bearings are sized so that each of them offers at least 0.34/2 mm, i.e. 0.17 mm, of radial play in this example.

FIGS. 19 to 21 are similar to FIGS. 16 to 18 but correspond to a valve 1 in which Dv<Dc, i.e. the sealing plane P′ of the shutter 5 is nearer the pin 7 than the sealing plane P of the body 2. As represented in FIG. 22, which represents the valve 1 in accordance with the second embodiment of the invention in plan view with the difference between the length l1 of the plate 30 and the length l2 of the plate 31 exaggerated; by virtue of the different lengths l1 and l2, in the closed position there are two leakage sections S on respective opposite sides of the plate 31.

Although the second embodiment of the invention described with references to FIGS. 12 to 21 relates to so-called “two-port” valves, the second embodiment of the invention also covers so-called “three-port” valves, as can be seen in FIG. 22.

The invention is not limited to the embodiments that have just been described.

Unless otherwise specified, the expression “including a” must be understood as synonymous with the expression “including at least one”.

Claims

1. A valve for an internal combustion engine, comprising:

a body including: a housing in which is disposed at least one bearing and a duct adapted to have a fluid pass through it, and a shutter mounted to pivot in the body by means of a pin received with radial play in the bearing, the shutter (5) pivoting between: an open position, and a closed position in which the shutter comes into contact with the body in a first contact area of the shutter on a first side of the pin and in a second contact area of the shutter on a second side of the pin opposite said first side, the passage of the shutter from the open position to the closed position being accompanied by radial movement of the pin in the bearing.

2. The valve as claimed in claim 1, wherein the valve lacks any flexible element disposed between the shutter and the body when the shutter is in the closed position.

3. The valve as claimed in claim 1, wherein the shutter and the pin are connected by a support extending along at least a portion of the pin.

4. The valve as claimed in claim 1, the body having a sealing plane of the body coming into contact with the first contact area and/or the second contact area of the shutter when the shutter in the closed position and the first contact area and/or the second contact area of the shutter being in a sealing plane of the shutter.

5. The valve as claimed in claim 4, wherein the distance between the center of the housing and the sealing plane of the body is greater than the distance between the center of the pin and the sealing plane of the shutter.

6. The valve as claimed in claim 4, wherein the distance between the center of the housing and the sealing plane of the body is less than the distance between the center of the pin and sealing plane of the shutter.

7. The valve as claimed in claim 1, wherein the first contact area and/or the second contact area of the shutter form a line contact with the body when the shutter is in the closed position.

8. The valve as claimed in claim 7, wherein the shutter has a rectangular shape and the first contact area and the second contact area being on opposite sides of the shutter.

9. The valve as claimed in claim 7, wherein only the first contact area of the shutter is in the sealing plane of the shutter, the second contact area of the shutter being in another plane of the shutter.

10. The valve as claimed in claim 9, the sealing plane of the shutter and said other plane of the shutter being on opposite faces of the shutter.

11. The valve as claimed in claim 1, wherein the first contact area and/or the second contact area of the shutter form a plane contact with the sealing plane of the body when the shutter is in the closed position.

12. The valve according to claim 11, wherein the first contact area and the second contact area of the shutter are in the sealing plane of the shutter and each of said contact areas of the shutter contacts the sealing plane of the body when the shutter is in the closed position.

13. The valve as claimed in claim 11, the first contact area of the shutter being on a first part of the shutter and on the upper face of said first part, the second contact area of the shutter being on a second part of the shutter and on the lower face of said second part.

14. The valve as claimed in claim 13, wherein the first part and the second part are rigidly coupled to each other to form the shutter in the sealing plane of the shutter.

15. The valve as claimed in claim 13, wherein the length of the second part of the shutter measured along the pin is less than the length of the first part of the shutter measured along the pin.

16. The valve as claimed in claim 4, the sealing plane of the shutter being a plane other than a plane intersecting the pin.

17. The valve as claimed in claim 1, wherein the valve is a three-port valve, and each of the open and closed positions comprise an extreme position for the pivoting of the shutter.