FR3057945B1 - SHUTTER GRILLET FOR A HEAT EXCHANGER COOLED BY AN AIR FLOW - Google Patents

Abstract

The invention relates to a shutter gate (3) for a heat exchanger (2) cooled by an air flow comprising a static shutter mask (18) capable of closing off a flow of air, the grid of shutter (3) being adapted to be removably mounted on a heat exchanger (2) by an elastic interlocking means.

Description

SHUTTER GRID FOR A HEAT EXCHANGER COOLED BY AN AIR FLOW

The description particularly relates to a shutter gate for heat exchanger cooled by an air flow, in particular for a charge air cooler.

In the field of motor vehicles, the boost gas to the engine is cooled by a heat exchanger commonly called charge air cooler (RAS). Some of these chillers, hereinafter referred to as air chokes, are cooled by air.

The air RAS comprise a bundle of conduits in which a supercharging gas to be cooled is circulated, a bundle of ducts comprising fins through which air circulates and inlet and outlet boxes for the passage of the supercharging gas at through the air RAS.

Under certain temperature conditions of the charge gas and air, especially in winter when the outside temperature is negative, frost forms in the charge gas circulation ducts. When the ice melts, for example when the vehicle is parked in a garage, a large amount of water accumulates in the outlet box of the air RAS. When the motor vehicle is restarted, water is sent to the engine, causing the engine to shut down and the starter fuse blowing.

To avoid this accumulation of frost, one solution is to mask part of the surface of the air RAS to prevent air from flowing through it.

One solution is to apply on the surface of the exchanger an adhesive tape impervious to air.

A disadvantage is that this solution is permanent.

The problem of frost in the air RAS is not present in the summer months when the outside temperature remains positive, it is advantageous to be able to remove the shutter mask for example the summer months in order to recover the full performance exchange of air RAS. For these purposes, it is also desirable that it is quick and easy to mount the shutter mask on the exchanger, for example by a garage during the winter equipment of the car. The self-adhesive waterproof tape does not have this feature.

The shutter mask can also remain mounted on the air RAS all year round. Nevertheless, it remains an advantage to be able to quickly mount a sealing mask on the exchanger, in particular for factory assembly.

The variable shutter and controlled mobile solutions found on the exchangers of the front of the vehicle, even if it would meet the need for partial shutter in the winter months and possibly non-shutter the summer months are too much expensive, complex and too large space for the need for masking air RAS. The invention therefore aims to solve these problems by providing a static and removable shutter grid adapted to be mounted and removed quickly and easily on a heat exchanger. The invention relates in particular to a shutter gate for a heat exchanger cooled by an air flow comprising a static shutter mask capable of closing off an air flow, the shutter gate being able to be mounted removable on a heat exchanger by a resilient interlocking means.

According to one aspect of the invention, the closure mask comprises a shape of T, L or I-strip.

According to one aspect of the invention, the resilient interlocking means comprises at least one fixing claw adapted to removably fix the shutter grid on a heat exchanger.

According to one aspect of the invention, the at least one fixing claw is able to removably fix the closing gate against a groove of a collector plate of a heat exchanger.

According to one aspect of the invention, the at least one fixing claw is made of material with the closing gate.

According to one aspect of the invention, the at least one fastening claw comprises a chamfer for assisting in mounting said shutter grille on the exchanger on which it is adapted to be mounted.

According to one aspect of the invention, the resilient interlocking means comprises at least two fastening claws connected by a support bar, the two fixing claws being able to removably fix the shutter grille on a heat exchanger. heat by digital support on the support bar.

According to one aspect of the invention, the resilient interlocking means comprises at least one retaining tab adapted to hold the closing gate on a heat exchanger.

According to one aspect of the invention, the at least one holding lug is able to hold the closing gate against a groove of a collector plate of a heat exchanger.

According to one aspect of the invention, the at least one retaining tab is made of material with the closing gate.

According to one aspect of the invention, the shutter gate comprises a frame.

According to one aspect of the invention, the frame comprises four sides substantially forming a rectangle.

According to one aspect of the invention, the shutter grid comprises longitudinal reinforcements.

According to one aspect of the invention, the shutter grid comprises lateral reinforcements.

According to one aspect of the invention, the lateral reinforcements are located between the longitudinal reinforcements.

According to one aspect of the invention, the lateral reinforcements are arranged in staggered relation to each other.

According to one aspect of the invention, the longitudinal reinforcements extend from one side of the frame to the closure mask.

According to one aspect of the invention, the longitudinal reinforcements are parallel to one side of the frame.

According to one aspect of the invention, the lateral reinforcements are parallel to one side of the frame.

According to one aspect of the invention, the shutter gate comprises at least one fixing claw and at least one retaining tab.

According to one aspect of the invention, the at least one attachment claw is connected to a first side of the frame and the at least one holding lug is connected to a side opposite the first side of said frame.

According to one aspect of the invention, the shutter gate comprises at least one absorption means capable of absorbing a thermal expansion of an exchanger on which the shutter gate is adapted to be mounted.

According to one aspect of the invention, the shutter gate comprises a frame, the at least one absorption means comprising a resilient U-shaped portion connected to the frame.

According to one aspect of the invention, the at least one absorption means comprises a U-shaped elastic connection between the frame of the closure grille and the at least one fixing claw.

According to one aspect of the invention, the at least one absorption means comprises a U-shaped elastic connection between the frame of the closure grille and the at least one retaining tab.

According to one aspect of the invention, the shutter grid comprises a frame having four sides substantially forming a rectangle, the shutter mask comprising a shutter strip extending along one side of the frame 10, over any the length of said side of the frame 10. The invention also relates to a heat exchange assembly comprising a heat exchanger comprising an outer face of entry of an air flow and a shutter gate, the grid shutter being removably mounted on said outer face by a resilient interlocking means.

According to one aspect of the invention, the outer surface of the inlet of the air flow of the heat exchanger comprises a passage surface of the air flow, the shutter mask sealing between 7 and 30% of the surface. passage of the air flow, preferably between 7 and 15%.

According to one aspect of the invention, the distance between the shutter mask of the shutter gate and the external inlet face of an air flow of the exchanger is between zero and four millimeters.

According to one aspect of the invention, the shutter gate is facing the outer face of an inlet of an air flow exchanger.

According to one aspect of the invention, the surface of the shutter gate opposite the surface of the external inlet face of an air flow of the exchanger is between 90% and 100%.

According to one aspect of the invention, the surface of the shutter gate facing the surface of the external inlet face of an air flow of the exchanger is between 30% and 90%.

According to one aspect of the invention, the heat exchanger is a charge air cooler. Other characteristics and advantages of the invention will appear on reading the description which follows. This is purely illustrative and should be read with reference to the accompanying drawings in which: - Figure 1 shows a perspective view of an exchange assembly comprising a closure grid mounted on a heat exchanger according to a first variant; of a first embodiment of the invention, - Figure 2 shows a perspective view of an exchange assembly according to Figure 1, the closing gate being partially mounted on the exchanger, - Figure 3 represents a side view of an exchange assembly according to FIG. 1, crossed by air; FIG. 4 represents a perspective view of the shutter grid according to FIGS. 1, 2 and 3, FIG. 5a shows a perspective view of two claws for fixing the shutter grille, FIG. 5b shows a sectional view of a claw for fixing the shutter grille against a groove of a collector plate of FIG. a heat exchanger 6a is a perspective view of a bracket holding the gate; FIG. 6b is a sectional view of a bracket for holding the gate against a groove of a header plate; of a heat exchanger, - Figure 7a shows a front view of an exchange assembly comprising a closure gate having a closure mask according to the first variant of the first embodiment according to Figures 1,2 and 3, - Figure 7b shows a front view of an exchange assembly comprising a closing gate having a closure mask according to a second variant of the first embodiment, - Figure 7c shows a front view. an exchange assembly comprising a shutter gate comprising a shutter mask according to a third variant of the first embodiment, - Figure 8 shows a front view of an exchange assembly comprising a shutter gate according to a second embodiment.

The following achievements are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each element mentioned in the context of an embodiment relates only to this same embodiment, or that features of this embodiment apply only to this embodiment.

Figures 1 and 2 illustrate a first embodiment of a heat exchange assembly 1, according to a first variant. The heat exchange assembly 1 comprises a heat exchanger 2 and a shutter gate 3. The heat exchanger 2 comprises a heat exchange bundle 7 comprising an outer face 8 of a flow inlet cooling air. The fluid to be cooled passes through the heat exchanger 1 through 17 inlet and outlet manifolds.

These manifolds 17 are fixed to the heat exchange bundle 7, each on a collector plate 4, for example by crimping, each of the collector plates 4 itself being fixed on the heat exchange bundle 7, for example by brazing.

Each manifold plate 4 comprises a groove 6 in which is inserted a manifold 17. This is visible in Figures 5b and 6b.

The shutter gate 3 comprises a shutter mask 18.

The shutter mask 18 is static. It is fixed in a predetermined position with respect to the shutter gate 3, for example, in the plane of the grid 18. The shutter mask 18 is not orientable and can not move on the grid of FIG. shutter 18.

The shutter gate 18 is removably mounted on the heat exchanger. It can be dismantled and reassembled on the heat exchanger without being damaged quickly and easily.

The assembly and disassembly does not require tools or additional parts. It can be done with one or two hands by an elastic interlocking means 11, more particularly visible in FIG.

The heat exchange bundle 7 of the heat exchanger 2 comprises fluid circulation ducts to be cooled, these ducts opening into the manifolds 17.

Between these fluid circulation ducts to be cooled are channels for circulating a cooling air fluid. These channels advantageously comprise fins to improve the heat exchange surface with air.

In the plane of the outside face 8 of the inlet of the cooling air stream of the heat exchanger 2, the circulation channels of a cooling air fluid define a surface 9 for passage of the air flow. . In FIG. 2, this surface 9 for the flow of air corresponds, for its visible part, that is to say, not hidden by the shutter gate 3, to the discontinuous gray surface of which only a part has been referenced. 9 not to weigh down the figure.

The passage surface 9 of the air flow consists of the sum of the area defined by each circulation channel of a cooling air fluid in the plane of the outside face 8 of the air flow inlet. cooling the heat exchanger 2.

The closure mask 18, when mounted on the heat exchanger 2 as illustrated in FIG. 1, closes between 7 and 30% of the air flow passage surface 9, preferably between 7 and 15 %.

Figure 3 illustrates the heat exchange assembly 1 according to a side view.

An air flow 5 arrives on the heat exchange unit 1, on the side on which the shutter gate 3 is mounted.

Part of the air flow 5 is blocked by the sealing mask 18 which is impervious to air.

Another part of the air flow 5 passes through the zone 29 of the shutter gate 3 which does not include the shutter mask 18, enters the heat exchanger 2 via its outer face 8 at its surface 9 for the passage of unobstructed air flow then passes through the heat exchanger 2 to emerge by its opposite face.

In FIG. 3, the distance between the shutter mask 18 of the shutter gate 3 and the external inlet face 8 of an air flow of the exchanger is zero. The shutter mask 18 is pressed against the outer face 8.

This distance is preferably between zero and four millimeters.

FIG. 4 illustrates the shutter gate 3.

The shutter grid 3 comprises a substantially coplanar frame 10 comprising four sides substantially forming a rectangle.

Advantageously, the shape of the grid adapts to the shape of the heat exchanger.

The coplanar characteristics of the shutter 3 and rectangular frame 10 are particularly suitable for a heat exchanger 2 whose beam 7 is substantially parallelepiped shape.

A heat exchange unit 1 comprising a heat exchanger 2, the external face 8 of the inlet of the cooling air flow has a significant radius of curvature advantageously comprises a non-coplanar shutter 3 of substantially identical radius of curvature to that of said outer face 8.

Similarly, a heat exchange unit 1 comprising a heat exchanger 2 whose outer face 8 inlet cooling air flow is trapezoidal may comprise a shutter 3 whose frame 10 is trapezoidal .

Thus, the frame 10 of the closing gate may be of different shapes, for example rectangular, round, trapezoidal, polygonal and coplanar or not.

In FIG. 4, the closure mask comprises a closure strip 18 extending along one side of the frame 10, along the entire length of said frame side 10. The closure mask 18 is a strip of closure shutter in the form of I.

The shutter grid 3 comprises longitudinal reinforcements 20 and lateral reinforcements 21.

The lateral reinforcements 21 are located between the longitudinal reinforcements 20.

The lateral reinforcements are arranged in staggered relation to each other. This makes it possible to distribute them better on the surface of the shutter grid.

In FIG. 4, the staggered arrangement is understood taking into account one of the sides of the grid 10. In an arrangement of three lateral reinforcements 21, two side reinforcements are fictitiously counted, these two imaginary reinforcements being included in one of the sides of the frame 10. The taking into account of dummy reinforcements is justified by the fact that in FIG. 4, a single lateral reinforcement 21 between two longitudinal reinforcements 20 is sufficient to stiffen the shutter grille 3.

Depending on the geometry of the closing gate 3, it may be necessary to add lateral reinforcements 21 to improve its mechanical strength.

In FIG. 4, the longitudinal reinforcements extend from one side of the frame 10 to the closing mask 18.

The longitudinal reinforcements 20 are parallel to one side of the frame.

The lateral reinforcements 21 are parallel to another side of the frame.

In the case of a rectangular frame, the longitudinal reinforcements 20 are perpendicular to the lateral reinforcements 21.

This geometry is not limiting. The number and location of the longitudinal and lateral reinforcements 21 may be different.

There may be no need to put such reinforcements 20 and 21.

The reinforcements 20 and 21 may make a non-zero angle and not right with the sides of the frame 10, for example 45 °.

Advantageously, the longitudinal reinforcements 20 are arranged on the closing gate 3 so as not to close the surface 9 for passage of the air flow when the shutter gate 3 is mounted on the exchanger 2.

For example, the longitudinal reinforcements 20 are arranged on the closing gate 3 so as to be arranged facing the circulation passages of the fluid to be cooled of the beam 7, that is to say between the discontinuities of the surface 9 of the passage of the air flow.

The shutter gate 3 comprises an elastic interlocking means 11.

The resilient interlocking means 11 comprises a fastening claw 13 adapted to removably fix the shutter grille 3 on the heat exchanger 2.

In particular, the fastening claw 13 is able to removably fix the shutter grille 3 against the groove 6 of the collector plate 4 of the heat exchanger 2.

The fastening claw 13 is made of material with the shutter gate 3.

The fastening claw 13 may also be a separate part of the frame 10 and connected by a mechanical connection to the frame 10, for example by gluing, brazing, force fitting, to form the closing gate 3.

The fastening claw 13 is located on one side of the frame 10 of the shutter grille 3. The fastening claw 13 coming from material with the shutter grille 3, a notch 25 on the side of the frame 10 is advantageously made to the location of the fastening claw 13 to facilitate the manufacture of the shutter grid 3.

The shutter grille 3 comprises four fastening claws 13 located on the same side of the frame 10.

As illustrated in FIG. 5a, the fastening claws 13 are connected two by two by a support bar 14.

A support, digital or via a machine, on the support bar 14 allows an elastic movement of the two claws 13 which are connected by this support bar 14. This allows an elastic interlocking of the grid shutter 3 on the heat exchanger 2.

Advantageously, the fastening claws 13 comprise at their end a chamfer 16 for assisting in mounting said shutter grid 3 on the exchanger on which it is adapted to be mounted.

As illustrated in FIG. 5b, the fixing claws 13 are designed to be fixed against the groove 6 of a collector plate 4 of the heat exchanger 2.

Thus, the fastening claws 13 comprise a support zone 27 of complementary shape to the groove 6 of the manifold plate 4 making it possible to ensure good fixing of the shutter grille 3 against the heat exchanger 2.

The shutter gate 3 comprises at least one absorption means 15 capable of absorbing a thermal expansion of the heat exchanger 2 on which the shutter gate is mounted.

As illustrated in FIGS. 5a and 5b, the absorption means 15 comprises a resilient U-shaped portion connected to the frame 10 of the closing gate 3.

The U-shape of the elastic portion is not limiting. It could be V-shaped, W-shaped, coil spring or leaf spring.

The absorption means 15 comes from material with the frame 10.

The absorption means 15 may also be a separate part of the frame 10 and connected by a mechanical connection to the frame 10, for example by colla, brazing, force fitting, to form the closing gate 3.

To reinforce the mechanical strength of the elastic U-shaped portion of the frame 10, a rib 19 is disposed at the junction between said U-shaped elastic portion and said frame 10.

In particular, the absorption means 15 comprises a U-shaped elastic connection between the frame of the closure grille and each fastening claw 13.

This elastic U-shaped connection between the frame of the closure grille and each fastening claw 13 makes it possible to absorb the thermal expansion between the heat exchanger 2 and the closing gate 3, but also makes it possible to provide a means of elastic interlock 11.

The fastening claws 13 may be arranged along two opposite sides of the frame 10 of the shutter grille 3.

For example, a pair of fixing claws 13 connected by a support bar 14 each disposed on two opposite sides of the shutter grid makes it possible to mount and dismount the shutter grid manually with two hands, one finger of each of the hands resting on each of the two support bars 14 simultaneously or not.

Several pairs of fastening claws 13 may be arranged on one and the same side of the frame 10 of the shutter grille 3, as illustrated in FIG. 4. The support on the support bar 14 may be digital or made by a machine.

As illustrated in FIG. 4, the resilient interlocking means 11 may also comprise at least one retaining lug 12, in particular four retaining tabs, capable of holding the closure grille 3 on the heat exchanger 2.

Each holding lug 12 is able to hold the closing gate 3 against a groove 6 of the header plate 4 of the heat exchanger 2.

Each holding lug 12 is made of material with the closing gate 3.

Each holding lug 12 may also be a separate part of the frame 10 and connected by a mechanical connection to the frame 10, for example by glue, brazing, force fitting, to form the closing gate 3.

The four retaining lugs 12 are located on one side of the frame 10 of the closure grille 3. Each retaining lug 12 coming from material with the closure grille 3, a notch 25 on the side of the frame 10 is advantageously realized. at the location of each retaining tab 12 to facilitate the manufacture of the shutter grid 3.

The shutter gate 3 comprises at least one absorption means 15 capable of absorbing a thermal expansion of the heat exchanger 2 on which the shutter gate is mounted.

The absorption means 15 comes from material with the frame 10.

The absorption means 15 may also be a separate part of the frame 10 and connected by a mechanical connection to the frame 10, for example by adhesive, brazing, force fitting, to form the closing gate 3.

As illustrated in FIGS. 6a and 6b, the absorption means 15 comprises a resilient U-shaped portion connected to the frame 10 of the closing gate 3.

The U-shape of the elastic portion is not limiting. It could be V-shaped, W-shaped, coil spring or leaf spring.

To reinforce the mechanical strength of the elastic U-shaped portion of the frame 10, a rib 19 is disposed at the junction between said U-shaped elastic portion and said frame 10.

In particular, the absorption means 15 comprises a U-shaped elastic connection between the frame of the closure grille and each retaining tab 12.

This elastic U-shaped connection between the frame of the closure grille and each retaining tab 12 makes it possible to absorb the thermal expansion between the heat exchanger 2 and the shutter gate 3.

The holding lug 12 extends substantially perpendicularly to the portion of the U-shaped elastic link to which it is connected.

In FIG. 6b, the groove 6 of the header plate is U-shaped and comprises a groove bottom 61, a groove side edge 62 and a raised edge 63.

The raised edge 63 is the end edge of the crimping plate 4, for example a crimping edge.

The lateral groove edge 62 is the edge of the groove 6 opposite the raised edge 63.

The groove bottom 61 is the portion between the raised edge 63 and the groove side edge 62.

The end edge 28 of the holding lug 12 bears against the header plate 4 when the closing gate 3 is mounted on the exchanger 2.

The holding lug 12 is also in abutment against the lateral edge of the groove 62 when the closing gate 3 is mounted on the exchanger 2.

Another embodiment (not shown) consists in the fact that the shutter grid 3 is maintained against a collecting plate 4 by pressing on the one hand the junction 26 between the elastic U-shaped connection and the locking tab. holding 12 against the groove bottom 61 of the collector plate 4 and secondly the holding lug 12 against the groove side edge 62. The shape of the junction 26 is then advantageously complementary to that of the throat bottom 61 against which it is maintained.

Advantageously, the closing gate 3 comprises at least one attachment claw 14 and at least one retaining lug 12.

The at least one fixing claw 13 is connected to one side of the frame 10 and the at least one holding lug 12 is connected to the opposite side of said frame 10.

In particular, as illustrated in FIG. 4, the shutter grille 3 comprises four retaining tabs 12 distributed on one side of the frame 10.

Advantageously, the holding lugs 12 are regularly distributed on one side of the frame 10.

The shutter gate 3 comprises two pairs of fastening claws 13 each connected by a support bar 14. The two pairs of fastening claws 13 are arranged on the opposite side of the frame 10 on which the four retaining tabs are distributed. 12.

Advantageously, the closing gate comprises fastening claws 13 disposed on one side of the frame 10 and holding lugs 12 arranged on the opposite side of the frame 10.

The number of fixing claws 13 and retaining tabs 12 depends on the geometry and the size of the shutter gate 3.

Figures 1 to 4 illustrate a shutter grid 3 comprising a substantially rectangular frame 10 whose large side is about 280 mm and the small side is about 220 mm.

In this configuration, it is advantageous for the shutter grille 3 to comprise four retaining lugs 12 and two pairs of fixing claws 13.

The mounting of the shutter grille 3 on the exchanger 2 comprising two collector plates comprises two steps:

The first assembly step, illustrated in FIG. 2, comprises an introduction of the retaining tabs 12 under a first collector plate 4 of the heat exchanger 2.

This makes it possible to maintain one side of the closing gate against the groove 6 of the header plate 4 of the heat exchanger

The second mounting step comprises a fixing of the retaining lugs 12 against a second collector plate 4 of the heat exchanger 2.

Fixing the retaining lugs 12 against the second collector 4 is carried out for example by the following succession of steps: - support, for example digital, on the support bars 14 pairs claws fixing 4, - lowering the grid shutter 3 on the side comprising the fixing claws 14, - introduction of the end of the fixing claws 14 under the collecting plate 4, in particular under the groove 6 of the header plate 4, - loosening of the support bars 14 .

The disassembly of the grid comprises the following two steps:

The first disassembly step comprises disconnecting the fastening claws against the second collector plate 4 of the heat exchanger 2.

The disconnection of the retaining lugs 12 from the second collector plate 4 is carried out for example by the following succession of steps: - support, for example digital, on the support bars 14 of the claw fixing pairs 4, - clearance of the end of the fixing claws 14 of the collecting plate 4, in particular of the groove 6 of the collecting plate 4, - lifting of the closing gate 3 on the side comprising the fixing claws 14 - loosening of the support bars 14.

The second disassembly step comprises a release of the holding lugs 12 from the first collector plate 4 of the heat exchanger 2.

The closure mask may be of different shape and for example comprise a shape of T, L or I strip.

FIG. 7a illustrates an I-shaped closure strip 18, which is the first variant of the first embodiment according to FIGS. 1 to 4.

Figure 7b illustrates a second variant of the first embodiment. The shutter mask 18 is T-shaped. The shutter mask 18 comprises a first sealing strip 181 extending along one side of the frame 10 over its entire length and a second sealing strip. 182 extending from the first sealing strip 181 to the opposite side of the frame side 10 along which the first strip 181 extends.

The second strip 182 extends at a non-zero distance from the two sides adjacent to the side of the frame 10 along which the first strip 181 extends.

Figure 7c illustrates a third variant of the first embodiment. The shutter mask 18 is L-shaped. The first strip 181 is identical to that of FIG. 7b.

The second strip 183 is different from that of FIG. 7b in that it extends along a side adjacent to the side of the frame 10 along which the first strip 181 extends.

All that has been described concerning the first variant of the first embodiment applies to the second and third variants of the first embodiment.

The shutter gate 3 is opposite the outer face 8 of an inlet of an air flow exchanger.

In FIGS. 1, 2, 3, 7a-7c, which illustrates a first embodiment, the surface of the shutter gate 3 opposite the surface of the outer face 8 of an inlet air flow. the exchanger is between 90% and 100%.

The surface of the shutter grid 3 is defined by the area of the frame 10. For example, when the frame 10 is substantially rectangular in shape and comprises two small sides and two long sides, the surface of the shutter gate 3 is a result of the product of the length of the short side by the length of the long side.

According to a second embodiment illustrated in FIG. 8, the area of the shutter gate 3 facing the surface of the external inlet face 8 of an air flow of the exchanger is between 30% and 90%.

All that has been described concerning the first embodiment applies to the second embodiment.

Claims (12)

Heat exchange assembly (1) comprising a heat exchanger (2) adapted to be cooled by an air flow (5) and a shutter gate (3) comprising a closure mask (18) static, the heat exchanger (1) having an outer face (8) of the inlet air flow (5), the closing gate (3) being removably mounted on said outer face (8) by means elastic interlocking element (11), the external airflow inlet face (8) (5) of the heat exchanger (2) comprising a surface (9) for passage of the air flow (5) , the closing mask (18) sealing between 7 and 30% of the surface (9) for passage of the air flow (5), preferably between 7 and 15%. 2. shutter grid (3) according to claim 1, the closure mask (18) comprising a shape of T, L or I strip. 3. shutter grid (3) according to any one of the preceding claims, the elastic interlocking means (11) comprising at least one fixing claw (13) adapted to removably fix the shutter gate (3). ) on a heat exchanger (2). 4. Blanking grid (3) according to the preceding claim, the at least one fastening claw (13) being adapted to removably fix the closing gate (3) against a groove (6) of a header plate (4) a heat exchanger (2). 5. Grid closure (3) according to any one of claims 3 to 4, the at least one fixing claw (13) being integral with the closing gate (3). 6. shutter grid (3) according to any one of the preceding claims, the elastic interlocking means (11) comprising at least two fastening claws (13) connected by a support bar (14), both fixing claws (13) being able to removably fix the closing gate (3) on a heat exchanger (2) by digital support on the support bar (14). 7. shutter grid (3) according to any one of the preceding claims, the resilient interlocking means (11) comprising at least one retaining tab (12) adapted to hold the closure gate (3) on a heat exchanger (2). 8. Blanking grid (3) according to the preceding claim, the at least one holding lug (12) being able to hold the closing gate (3) against a groove (6) of a header plate (4). a heat exchanger (2). 9. shutter grid (3) according to any one of claims 7 to 8, the at least one retaining tab (12) being integral with the closing gate (3). 10. Shutter grid (3) according to any one of the preceding claims, comprising at least one absorption means (15) adapted to absorb thermal expansion of an exchanger (2) on which the grid of shutter (3) is suitable for mounting. 11. Blanking grid (3) according to claim 10, the closing gate (3) comprising a frame (10), the at least one absorption means (15) comprising a resilient U-shaped portion connected to the frame ( 10). 12. heat exchange unit (1) according to any one of the preceding claims, the heat exchanger (2) being a charge air cooler.