FR3137635A1 - COLLISION DETECTION SYSTEM FOR MOTOR VEHICLE AND VEHICLE COMPRISING SUCH A SYSTEM - Google Patents

Abstract

The invention relates to a collision detection system (1) for a motor vehicle, said system (1) comprising a shock absorption device (3) comprising a housing (9), at least two pressure sensors (7), a fluid pipe (5) each of whose ends is connected to one of said pressure sensors (7), said pipe (5) being housed at least partially in the housing (9) of said absorption device (3), characterized in that said system (1) comprises means (11) for regulating the pressure of the fluid of said pipe (5). Figure to be published with the abstract: Fig. 2

Description

COLLISION DETECTION SYSTEM FOR MOTOR VEHICLE AND VEHICLE COMPRISING SUCH A SYSTEM

The present invention relates to the field of collision detection systems for motor vehicles, in particular collisions with pedestrians or the like.

Motor vehicles include various protection systems intended to ensure the protection of users, but also of third parties. Among the various protection systems, there are collision detection systems which are systems intended to be installed in various locations on the vehicle and configured to detect an impact between the vehicle and an object external to the vehicle, such as pedestrians. , bicycles, other vehicles, etc.

These collision detection systems may in particular be accelerometers which detect a collision depending on the variation in the acceleration of the vehicle, or even pressure sensors which detect a collision on the basis of a variation in pressure, generally an increase , detected by said pressure sensors.

There are also collision detection systems dedicated to detecting collisions with pedestrians or the like, the aim of which is to reduce the shock suffered by the pedestrian during a collision with the vehicle. For this, the collision detection system is located in a bumper of the vehicle, for example the front, and is associated with an active type hood. Thus, when a collision is detected by the collision detection system at the front bumper of the vehicle, dedicated means are activated to raise the hood in order to cushion the pedestrian's impact on this. hood.

Indeed, the fact that the hood can be raised after detection of a collision with a pedestrian makes it possible to increase the distance between the hood and the rigid components placed in the engine compartment, which allows the hood to deform during the collision with the pedestrian and to reduce the violence of the pedestrian's impact with the vehicle, and more particularly with the hood.

Furthermore, among the different types of collision detection systems with a pedestrian or equivalent, there are in particular those comprising a shock absorption device, an element also referred to as an absorber, in which a fluid pipe is placed. each end of which is connected to a pressure sensor. Each of said sensors is thus configured to detect variations in fluid pressure. In addition, each of the sensors is for example connected to an on-board computer of the vehicle or another organ which can, if necessary, trigger an appropriate safety organ, for example an active bonnet of the vehicle.

The collision detection system is therefore installed at the level of a bumper, so during a collision, the object or pedestrian hitting the bumper will cause an impact at the level of the absorber and therefore of the pipe of fluid causing a variation in pressure of said fluid detectable by the pressure sensor(s). Depending on the pressure variation measured and received by the vehicle's on-board computer, appropriate vehicle safety systems are therefore triggered.

This type of collision detection system by measuring a pressure variation requires in particular that the fluid pipe be protected as best as possible from environmental attacks, and to avoid, among other things, false collision detections.

It is also necessary to define a route for the fluid pipe in the shock absorption device, in particular to respect maximum radii of curvature and avoid pinching of said pipe. In addition, it is necessary for the path of the pipe along said shock absorption device to be as regular and homogeneous as possible in order to not favor any area of said absorption device during a shock over another.

Furthermore, at rest (or when the vehicle is moving), the pressure of the fluid in the pipe must be as homogeneous as possible, also to prevent the pressure variations generated by an impact from varying depending on the position of the impact on the bumper, and therefore on the shock absorption device.

The present invention thus proposes to remedy at least one of the aforementioned drawbacks by proposing a new collision detection system for a motor vehicle, said system comprising:
- a shock absorption device comprising a housing;
- at least two pressure sensors;
- a fluid pipe, each end of which is connected to one of said pressure sensors;
said pipe being housed at least partially in the housing of said absorption device,
characterized in that said system comprises means for regulating the pressure of the fluid of said pipe.

Said collision detection system according to the invention thus comprises dedicated means for regulating the pressure of the fluid and thus making it possible to accommodate, for example directly, the fluid pipe in said shock absorption device according to a predefined path presenting for example curvatures or incurvations, while limiting the appearance of localized overpressures which could harm the operation of said system.

According to a possible characteristic, said pressure regulation means are mechanical means.
Said pressure regulation means are advantageously mechanical, such as pressure regulation elements or structures, because they are simple, robust and inexpensive to implement.

According to another possible characteristic, said pressure regulating means comprise openings arranged in the walls of the housing housing said fluid pipe.
The fact that the walls of the housing housing said pipe have openings makes it possible, on the one hand, to reduce the stresses exerted by the walls on the pipe, and, on the other hand, for the pipe to deform during variations in pressure of the pipe. fluid and avoid local overpressure.

According to another possible characteristic, said pressure regulation openings are arranged alternately on opposite walls of said housing.
There is thus a distribution of openings, or notches, arranged on the opposite free walls of the housing housing the fluid pipe, advantageously in an alternating manner to limit the appearance of excess pressure zones in the fluid pipe and that the pressure is as homogeneous as possible in said pipe.
The pressure regulating means thus comprise openings or notches giving substantially a crenel shape to said walls of said housing.

According to another possible characteristic, said openings of the pressure regulating means are arranged in a regular manner, that is to say that the distance between each opening on a wall of the housing is substantially identical.

According to another possible characteristic, said fluid pipe has at least one curved portion, said pressure regulating means being arranged as close as possible to said at least one curved portion of said pipe.
The pressure of the fluid in the pipe is greater after a curved portion of the pipe, thus, by positioning pressure regulating means as close as possible to said curvature or curvature of the pipe, there is a reduction in localized overpressures.

According to another possible characteristic, said housing has at least one curved portion, said pressure regulating means being arranged as close as possible to said at least one curved portion of said housing.

By “arranged as close as possible” is meant the fact that the regulating means are arranged just after and/or sufficiently close to a curved (or curved) portion of the pipe to limit overpressure of the fluid in the pipe, and preferably arranged in a straight portion of the pipe (and generally of the housing).

According to another possible characteristic, said fluid disposed in the pipe is a liquid, such as water, brine, brake fluid, etc.

According to another possible characteristic, the walls of the housing and/or the pipe have(have) a radius of curvature less than 35 millimeters, and preferably less than 20 millimeters.

According to another possible characteristic, said fluid pipe has an elasticity of at least 60 Shore A, said pipe being for example made of silicone.

According to another possible characteristic, said absorption device is made of polymer foam, for example polyphenylene ether foam, having a density of between 40 g/L and 120 g/L.

According to another possible characteristic, said system comprises means for holding said pipe in the housing of the absorption device.
Said system thus includes holding means to facilitate fixing the pipe in the housing, thus simplifying the manufacture of the collision detection system on the production line.

According to another possible characteristic, said holding means are mechanical means.
Said holding means are advantageously mechanical, because they are simple, robust and inexpensive to implement.

According to another possible characteristic, said holding means are studs extending projecting into said housing.
The presence of studs to hold the pipe in the housing makes it possible to limit the use of attached fixing means, such as clips, facilitating the manufacture of the system according to the invention and reducing its manufacturing cost.

According to another possible characteristic, said holding means are integral with the walls of said housing. The fact that the holding means, such as projections, studs or others, come integrally with the housing, and more generally with the shock absorption device, facilitates the manufacturing process and reduces the cost of manufacturing said absorption device.

According to another possible characteristic, said absorption device has a first face and a second opposite face, called respectively front face and rear face (in the mounted position), said housing being arranged in the second face of said absorption device.
Said absorption device is advantageously intended to be arranged, in the mounted position, in a bumper, front or rear, generally between a bumper reinforcement and a bumper skin, and generally in the lower part.

According to another possible characteristic, said housing has a substantially circular section.
Said housing housing said fluid pipe advantageously has a section for holding said pipe of substantially circular section, so that the walls of the housing exert the most homogeneous mechanical stress possible on said pipe.

The invention also relates to a motor vehicle bumper, characterized in that it comprises a collision detection system comprising all or part of the characteristics set out above, as well as a bumper skin and a reinforcement. bumper.
Furthermore, said collision detection system according to the invention is advantageously arranged between the bumper skin and said bumper reinforcement.

The invention also relates to a motor vehicle, characterized in that said vehicle comprises a collision detection system comprising all or part of the characteristics set out above.

The invention will be better understood, and other aims, details, characteristics and advantages thereof will appear more clearly during the following description of a particular embodiment of the invention, given solely for illustrative purposes and not restrictive, with reference to the appended drawings, in which:
- There illustrates a schematic, front and perspective view of a collision detection system according to the invention;
- there is a rear view of the system ;
- there [ ] is an enlarged and partial view of the pressure regulation means of the system of the ;
- there is another enlarged and partial view of part of the system of the ;
- there is an enlarged, cross-sectional view of part of the system of the .

In the following description, the term “include” is synonymous with “include” and is not restrictive in that it authorizes the presence of other elements in the vehicle, or the structure to which it relates. It is understood that the term “understand” includes the terms “consist of”. Likewise, the terms “lower”, “upper”, “front”, “rear”, “longitudinal” and “transverse” will be understood in relation to the general orientation of the motor vehicle, whether thermal or hybrid. or electric.

Note that in the different figures, the same references designate identical or similar elements.
In addition, an orthogonal reference XYZ is defined in relation to the vehicle, namely:
- an X axis, defining a longitudinal and horizontal direction of the vehicle,
- a Y axis, defining a transverse and horizontal direction, which with the X axis defines a horizontal XY plane,
- a Z axis, defining a vertical direction, orthogonal to the horizontal XY plane, the Z axis with the X axis defining a vertical XZ plane.

In the present application, it will be noted that “substantially parallel” means a direction deviating by at most 20°, or even by at most 10° or at most 5° from a parallel direction. It should also be noted that “substantially orthogonal” means a direction deviating by at most 20°, or even by at most 10° or by at most 5°, from an angle with a value of 90°. .

There thus illustrates a schematic, front and perspective view of a collision detection system 1 for a motor vehicle. While the is a rear view of system 1 of the .

Said system 1 comprises a shock absorption device 3, which is therefore an element configured to absorb the energy following a collision (that is to say the energy of the resulting shock). Said device 3 can also be referred to as an absorber and the two terms will be used interchangeably below.

Thus, the absorber 3 is an element having a shock absorption function and which is for example placed in a bumper of a motor vehicle, in particular between a bumper reinforcement and a bumper skin.

Said absorber 3 has an elongated shape and is therefore intended to be placed in a front or rear bumper of a motor vehicle. Said absorber 3 can have various shapes, openings, fixing means, structural elements, etc. depending on the technical constraints imposed on said absorber 3 to allow its integration into a bumper of the vehicle. While allowing the use of other vehicle components, sensors, cameras, etc. arranged on related elements or located near said absorber 3.

Said absorber 3 has two opposite longitudinal ends 3a and 3b, as well as a middle zone 3c connecting said longitudinal ends 3a and 3b. The absorber 3 or shock absorption device is for example in one piece and/or made of polymer foam, such as polypropylene foam, polyphenylene ether, etc. Advantageously, the polymer foam of the absorber 3 has a density of between 40 and 120 g/L.

In addition, said absorber 3 comprises two opposite faces, a first face 3d, called the front face, that is to say a face intended to be oriented towards the front or the exterior of the vehicle, when the reinforcement 3 is in mounted position, as well as a second 3rd face, called the 3rd rear face, that is to say a face intended to be oriented towards the vehicle (or the interior of the vehicle) when the reinforcement 3 is in the mounted position.

It will thus be noted that in the mounted position, the absorber 3 therefore extends transversely with respect to the longitudinal axis of the vehicle (or X axis, and substantially orthogonal to said X axis), and/or in a substantially parallel direction. to the Y axis of said vehicle.

Said system 1 also includes a fluid pipe 5 and two pressure sensors 7. Said pipe 5 thus has two opposite ends at the end of each of which is fixed or connected a pressure sensor 7, distinct from one another. The pipe 5 advantageously extends along an axis substantially parallel to the longitudinal axis of said absorber 3.

It will be noted that we mean the fact that the pressure sensors 7 are connected to the fluid pipe 5, the fact that the pressure sensors are configured to measure the pressures or pressure variations of the fluid of said pipe 5. While the fluid of the pipe 5 is advantageously a liquid, such as water, brine, brake fluid, etc.

In addition, said pressure sensors 7 are connected to the on-board computer (not shown) of the motor vehicle, in particular to report the measured pressure values. Thus, the on-board computer is configured to trigger, depending on the pressure values measured by said pressure sensors 7, one or more safety devices of the vehicle, such as an active hood.

It will also be noted that said pressure sensors 7 are advantageously fixed to the absorber 3 and/or to other structural elements (not shown) of the vehicle, such as a bumper reinforcement.

In addition, said absorber 3 comprises a housing 9 configured to accommodate or accommodate, at least partially, the pipe 5, for example force-fitted into said housing 9. Furthermore, said housing 9 is advantageously located on the rear face 3e of said absorber 3, in order to protect said fluid pipe 5 from environmental attacks (and limit the detection of false positive collisions).

Said housing 9 generally extends over the entire length of said absorber 3, therefore from one end 3a to the other 3b and through the middle zone 3c. Said housing 9 of the absorber 3 may have curved or curved portions 9a depending on integration or other constraints. Consequently, said fluid pipe 5 may also have one or more curved or curved portions 5a (curved shape generally imposed by said housing 9).

Advantageously, the radius of curvature of said curved portions 5a and/or 9a (respectively of the pipe 5 and/or the housing 9) is less than 35 millimeters, and preferably less than 20 millimeters.

Thus, when an impact or collision occurs at the level of the bumper, the absorber 3 deforms, causing the localized compression of the pipe 5, and thus causing a variation in pressure of the fluid contained in said pipe 5. This variation in pressure is detected by one or both pressure sensors 7 and thus makes it possible to detect, at least approximately, the position and/or intensity of the shock (or collision) at the level of the absorber 3, and therefore at what level of the bumper (where said absorber 3 is located).

In addition, depending on the intensity of the shock and/or location, that is to say the pressure variation recorded by said pressure sensors 7, the on-board computer can be configured to trigger a safety device. , for example a change in the position of the vehicle hood (active type hood), in order to minimize the damage suffered by a possible pedestrian coming into contact with the vehicle, such as the hood.

In addition, said fluid pipe 5 advantageously has an elasticity of at least 60 Shore A (that is to say that the material from which said pipe is made has at least said elasticity characteristics).

Furthermore, the housing 9 is advantageously an open cavity arranged directly in the absorber 3, the holding section of which, that is to say the section in contact with the pipe 5, has for example a substantially circular section (section according to an XZ plane in the mounted position). The shape of the holding section of housing 9 is advantageously the same over the entire length of housing 9.

It will be noted that the shape of said section of housing 9 generally has a shape similar or close to that of the pipe 5, this in order to optimize the retention of the pipe in the housing 9 and to homogenize the stresses exerted by the wall of the housing 9 on the pipe 5 (and thus also homogenize the pressure of the fluid in said pipe, without the pipe being crushed).

As more particularly visible at the , said housing 9 also includes pressure regulation means 11, among other mechanical means, making it possible to limit the appearance of local overpressures, for example following curvature or curvatures of the housing 9, and therefore of the pipe 5. It will be noted, however, that It is advantageous to provide regulation means 11 even in the absence of such geometries to allow more freedom to said pipe 5 and allow better homogeneity (or distribution) of the fluid pressure all along the pipe 5.

Thus, the regulating means 11 are advantageously openings 11a or notches arranged in the walls of said housing 9 (and therefore the absorber 3), in particular at the level of the housing holding section 9 (that is to say the walls of housing 9 defining the holding section of said pipe).

Said pressure regulation openings 11a are arranged alternately on opposite walls of said housing 9, so that said regulation means 11 have substantially the shape of slots. It will be noted that by “alternating openings” is meant the fact that the openings 11a arranged on opposite walls of the housing 9 are offset relative to each other (said opposite openings are not or only partially facing each other. ).

In addition, said openings 11a of the pressure regulating means 11 are advantageously arranged in a regular manner, that is to say that the distance between each opening 11a on a wall of the housing 9 is substantially identical. The distance between each opening 11a (between two consecutive openings located on the same wall) is for example less than 20 mm, and preferably less than 10 mm.

Furthermore, said regulating means 11 (and therefore the openings 11a) are arranged as close as possible to said at least one curvature of said pipe 5 (or of the housing 9), and advantageously in a straight portion of the pipe and/or of the housing.

Furthermore, without limitation, in the embodiment described, the curved portions of the pipe 5a and the housing 9a, more particularly visible at the , are located at the ends 3a and 3b of said absorber 3, while the regulating means 11 are located in the middle zone 3c of said absorber 3.

It will be noted that "arranged as closely as possible" means the fact that the regulating means are arranged just after and/or sufficiently close to a curved (or curved) portion to limit overpressure of the fluid in the pipe and preferably in a straight portion of the pipe.

Advantageously, said regulating means 11, and the openings 11a, are arranged at a distance less than 20 mm (or millimeters) from the curved portion 5a of the pipe 5 (and therefore also from the curved portion 9a of the housing 9), preferably at a distance of less than 10 mm, and even more preferably at a distance of less than 5 mm.

In addition, the system 1 advantageously comprises, for each curved portion 5a of the pipe 5a, associated pressure regulation means 11, the number of openings 11a, the spacing between openings 11a, etc. being for example a function of the radius of curvature of said curved portion 5a.

As more particularly visible at the , said system 1 can also advantageously comprise means 15 for holding said pipe 5 in the housing 9 of the absorber 3.

The holding means 15 are mechanical means, such as studs 15a (or protuberances) extending projecting into said housing 9, for example from the opposite walls of the housing 9, and advantageously facing each other .

In addition, said studs 15a or protuberances are advantageously made integrally with the absorber 3. Said studs 15a are also preferably located at the open longitudinal ends of the housing 9.

In an embodiment not shown, the holding means 15 (and the studs 15a) are an attached part and/or overmolded on the absorber 3.

In another alternative embodiment not shown, the pressure regulating means 11 are an attached part and/or overmolded on the absorber 3, the absorber 3 comprising one or more recesses (or cavities) to arrange said regulating means therein. 11.

Claims (10)

Collision detection system (1) for a motor vehicle, said system (1) comprising:
- a shock absorption device (3) comprising a housing (9);
- at least two pressure sensors (7);
- a fluid pipe (5) each of whose ends is connected to one of said pressure sensors (7);
said pipe (5) being housed at least partially in the housing (9) of said absorption device (3),
characterized in that said system (1) comprises means (11) for regulating the pressure of the fluid of said pipe (5). System (1) according to the preceding claim, characterized in that said pressure regulating means (11) are mechanical means. System (1) according to any one of the preceding claims, characterized in that said pressure regulating means (11) comprise openings (11a) arranged in the walls of the housing (9) housing said fluid pipe (5). System (1) according to the preceding claim, characterized in that said openings (11a) of the pressure regulating means are arranged alternately on opposite walls of said housing (9). System (1) according to the preceding claim, characterized in that said fluid pipe (5) has at least one curved portion (5a), said pressure regulating means (11) being arranged as close as possible to said at least one portion curved 5(a) of said pipe 5. System (1) according to any one of the preceding claims, characterized in that said fluid pipe (5) has an elasticity of at least 60 Shore A. System (1) according to any one of the preceding claims, characterized in that said absorption device (3) is made of polymer foam having a density of between 40 g/L and 120 g/L. System (1) according to any one of the preceding claims, characterized in that it comprises means (15) for holding said pipe (5) in the housing (9) of the shock absorption device (3). System (1) according to the preceding claim, characterized in that said holding means (15) are studs (15a) extending projecting into said housing (9). Motor vehicle, characterized in that it comprises a collision detection system (1) according to any one of the preceding claims.