COLLISION DETECTION SYSTEM FOR MOTOR VEHICLES AND VEHICLES EQUIPPED WITH SUCH A SYSTEM

Abstract

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

Description

Title of the invention: COLLISION DETECTION SYSTEM FOR MOTOR VEHICLES AND VEHICLES COMPRISING SUCH A SYSTEM

[0001] The present invention relates to the field of collision detection systems for motor vehicles, in particular collisions with pedestrians or equivalents.

[0002] Motor vehicles include various protection systems designed to ensure the safety of users, but also of third parties. Among these various protection systems are collision detection systems, which are systems designed to be installed at 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.

[0003] These collision detection systems may include accelerometers which detect a collision based on the variation in the acceleration of the vehicle, or pressure sensors which detect a collision based on a variation in pressure, generally an increase, detected by said pressure sensors.

[0004] There are also collision detection systems specifically designed for detecting collisions with pedestrians or equivalent vehicles, the purpose of which is to reduce the impact experienced by the pedestrian during a collision with the vehicle. For this purpose, the collision detection system is located in a bumper of the vehicle, for example, the front bumper, and is associated with an active hood. Thus, when a collision is detected by the collision detection system at the level of the vehicle's front bumper, dedicated means are activated to raise the hood in order to cushion the impact of the pedestrian on the hood.

[0005] Indeed, the fact that the hood can lift after detection of a collision with a pedestrian makes it possible to increase the distance between the hood and the rigid components located in the engine compartment, which allows the hood to deform during the collision with the pedestrian and to reduce the violence of the impact of the pedestrian with the vehicle, and more particularly with the hood.

[0006] Furthermore, among the various types of pedestrian collision detection systems, there are those comprising a shock absorption device, also known as an absorber, in which a fluid tube is arranged, each end of which is connected to a pressure sensor. Each of these sensors is thus configured to detect variations in fluid pressure. In addition, each sensor is, for example, connected to the vehicle's on-board computer or another component that can, if necessary, trigger an appropriate safety device, such as an active vehicle hood.

[0007] The collision detection system is therefore installed at the level of a bumper. Thus, during a collision, the object or pedestrian striking the bumper will cause an impact on the energy absorber and therefore on the fluid hose, resulting in a pressure variation of said fluid that can be detected by the pressure sensor(s). Depending on the pressure variation measured and received by the vehicle's on-board computer, the appropriate safety systems of the vehicle are then activated.

[0008] 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 aggressions, and avoid among other things false collision detections.

[0009] It is also necessary to define a path for the fluid pipe within the shock-absorbing device, in particular to respect maximum bending radii and avoid pinching of said pipe. Furthermore, it is necessary that the path of the pipe along said shock-absorbing device be as regular and homogeneous as possible so as not to favor any area of ​​said shock-absorbing device over another during an impact.

[0010] Furthermore, at rest (or when the vehicle is in motion), the fluid pressure in the pipe must be as homogeneous as possible, also to prevent pressure variations caused by an impact from varying according to the position of the impact on the bumper, and therefore on the shock absorption device.

[0011] The present invention thus aims to remedy at least one of the aforementioned drawbacks by proposing a new collision detection system for motor vehicles, 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 within the housing of said absorption device, characterized in that said system includes means for regulating the pressure of the fluid in said pipe.

[0012] Said collision detection system according to the invention thus includes dedicated means for regulating the fluid pressure and thus allowing the fluid pipe to be housed, for example directly, in said shock absorption device along a predefined path presenting, for example, bends or curves, while limiting the occurrence of localized overpressures which could harm the operation of said system.

[0013] According to one possible characteristic, said pressure regulation means are mechanical means. The said means of pressure regulation are advantageously mechanical, such as pressure regulation elements or structures, because they are simple, robust and inexpensive to implement.

[0014] According to another possible feature, said pressure regulation means include openings provided in the walls of the housing containing said fluid pipe. The fact that the walls of the housing containing said pipe have openings allows, on the one hand, to reduce the stresses exerted by the walls on the pipe, and, on the other hand, to allow the pipe to deform during variations in fluid pressure and to avoid local overpressures.

[0015] According to another possible feature, said pressure regulating 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 accommodating the fluid pipe, advantageously in an alternating manner to limit the appearance of overpressure zones in the fluid pipe and to ensure that the pressure is as homogeneous as possible in said pipe. The pressure regulating means thus include openings or notches giving a substantially crenellated shape to the walls of said housing.

[0016] According to another possible feature, said openings of the pressure regulating means are arranged regularly, that is to say, the distance between each opening on a wall of the housing is substantially identical.

[0017] According to another possible feature, said fluid pipe has at least one curved portion, said pressure regulating means being disposed as close as possible to said at least one curved portion of said pipe. The fluid pressure in the pipe is greater after a bend in the pipe; therefore, by positioning pressure regulating means as close as possible to said bend or inclination of the pipe, localized overpressures are reduced.

[0018] According to another possible feature, 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.

[0019] The term "arranged as close as possible" means that the regulating means are arranged just after and / or sufficiently close to a curved (or curved) portion of the pipe to limit overpressures of the fluid in the pipe, and preferably arranged in a straight portion of the pipe (and generally of the housing).

[0020] According to another possible characteristic, said fluid disposed in the pipe is a liquid, such as water, glycol water, brake fluid, etc.

[0021] According to another possible feature, the walls of the housing and / or the pipe have a radius of curvature of less than 35 millimeters, and preferably less than 20 millimeters.

[0022] 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.

[0023] According to another possible feature, said absorption device is made of polymer foam, for example polyphenylene ether foam, having a density between 40 g / L and 120 g / L.

[0024] According to another possible feature, said system includes means for retaining said pipe in the housing of the absorption device. The system includes means of support to facilitate the fixing of the pipe in the housing, thus simplifying the manufacture of the collision detection system on the production line.

[0025] According to another possible characteristic, said retaining means are mechanical means. These means of support are advantageously mechanical, because they are simple, robust and inexpensive to implement.

[0026] According to another possible feature, said retaining means are studs extending outwards into said housing. The presence of studs to hold the pipe in the housing limits the use of additional fastening means, such as staples, facilitating the manufacture of the system according to the invention and reducing its manufacturing cost.

[0027] According to another possible feature, said retaining means are formed as part of the wall of said housing. The fact that the retaining means, such as projections, studs, or the like, are formed as part of the housing, and more generally with the shock-absorbing device, facilitates the manufacturing process and reduces the manufacturing cost of said shock-absorbing device.

[0028] According to another possible feature, said absorption device has a first face and a second opposite face, referred to respectively as front face and rear face (in mounted position), said housing being arranged in the second face of said absorption device. The said absorption device is advantageously intended to be placed, 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.

[0029] According to another possible characteristic, said housing has a substantially circular cross-section. The housing containing the fluid pipe advantageously has a pipe retaining section with a substantially circular cross-section, so that the walls of the housing exert the most homogeneous mechanical stress possible on the pipe.

[0030] The invention also relates to a motor vehicle bumper, characterized in that it comprises a collision detection system having all or part of the features stated above, as well as a bumper skin and a bumper reinforcement. Furthermore, the said collision detection system according to the invention is advantageously arranged between the bumper skin and said bumper reinforcement.

[0031] 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 stated above.

[0032] The invention will be better understood, and other objects, details, features and advantages thereof will become more apparent from the following description of a particular embodiment of the invention, given solely by way of illustration and not limitation, with reference to the accompanying drawings, in which: - Fig. 1 illustrates a schematic, front and perspective view of a collision detection system according to the invention; - [Fig.2] is a rear view of the system in [Fig.1]; - the [[Fig.3]] is an enlarged and partial view of the pressure regulation means of the system of the [Fig.2]; - [Fig. 4] is another enlarged and partial view of part of the system of the [Fig.2]; - [Fig.5] is an enlarged, cross-sectional view of part of the system in [Fig.2],

[0033] In the following description, the term "include" is synonymous with "include" and is not limiting in that it permits the presence of other elements in the vehicle, or the structure to which it relates. It is understood that the term "include" includes the terms "consist of". Similarly, the terms "lower", "upper", "front", "rear", "longitudinal" and "transverse" shall be understood in relation to the general orientation of the motor vehicle, whether it is internal combustion, hybrid or electric.

[0034] It should be noted that in the different figures, the same references designate identical or similar elements. Furthermore, an orthogonal XYZ coordinate system is defined with respect 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, together 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.

[0035] In this application, it should be noted that "substantially parallel" means a direction deviating by no more than 20°, or even by no more than 10° or 5°, from a parallel direction. It should also be noted that "substantially orthogonal" means a direction deviating by no more than 20°, or even by no more than 10° or 5°, from an angle of 90°.

[0036] Figure 1 thus illustrates a schematic, front and perspective view of a collision detection system 1 for a motor vehicle. While Figure 2 is a rear view of the system 1 of Figure 1.

[0037] Said system 1 comprises a shock-absorbing device 3, which is therefore an element configured to absorb energy following a collision (i.e., the resulting shock energy). Said device 3 may also be referred to as an absorber, and the two terms will be used interchangeably hereafter.

[0038] Thus, the absorber 3 is an element having a shock absorption function and which is for example disposed in a motor vehicle bumper, in particular between a bumper reinforcement and a bumper skin.

[0039] 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 may have various shapes, openings, means of attachment, structural elements, etc., depending on the technical constraints imposed on said absorber 3 to allow its integration into a vehicle bumper. This integration also allows the use of other vehicle components, sensors, cameras, etc., located on related elements or near said absorber 3.

[0040] Said absorber 3 has two opposing longitudinal ends 3a and 3b, as well as a median zone 3c connecting said longitudinal ends 3a and 3b. The absorber 3 or shock-absorbing device is, for example, a single piece and / or made of polymer foam, such as polypropylene foam, polyphenylene ether foam, etc. Advantageously, the polymer foam of the absorber 3 has a density between 40 and 120 g / L.

[0041] Furthermore, 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 outside of the vehicle, when the reinforcement 3 is in the mounted position, and a second face 3e, called the rear face 3e, that is to say a face intended to be oriented towards the vehicle (or the inside of the vehicle) when the reinforcement 3 is in the mounted position.

[0042] It should 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 in a substantially orthogonal to said X axis), and / or in a direction substantially parallel to the Y axis of said vehicle.

[0043] 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.

[0044] It will be noted that we understand that the pressure sensors 7 are connected to the fluid pipe 5, that the pressure sensors are configured to measure the pressures or pressure variations of the fluid in said pipe 5. Whereas the fluid in pipe 5 is advantageously a liquid, such as water, glycol water, brake fluid, etc.

[0045] Furthermore, said pressure sensors 7 are connected to the vehicle's on-board computer (not shown), in particular to transmit the measured pressure values. Thus, the on-board computer is configured to trigger, based on the pressure values ​​measured by said pressure sensors 7, one or more vehicle safety features, such as an active hood.

[0046] It should also be noted that said pressure sensors 7 are advantageously fixed to the absorber 3 and / or to other (not shown) structural elements of the vehicle, such as a bumper reinforcement.

[0047] Furthermore, said absorber 3 includes a housing 9 configured to house or accommodate, at least partially, the pipe 5, for example pressed into said housing 9. Moreover, 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 aggressions (and limit the detection of false positive collisions).

[0048] Said housing 9 generally extends along 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 bent portions 9a depending on integration or other constraints. Consequently, said fluid pipe 5 may also have one or more curved or bent portions 5a (the bent shape generally imposed by said housing 9).

[0049] 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.

[0050] Thus, when a shock or collision occurs at the bumper, the absorber 3 deforms, causing localized compression of the pipe 5, and thereby causing a pressure variation of the fluid contained in said pipe 5. This pressure variation is detected by one or both of the 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 absorber 3, and therefore at what level of the bumper (where said absorber 3 is located).

[0051] Furthermore, depending on the intensity of the shock and / or location, i.e. 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 position of the vehicle hood (active hood type), in order to minimize the damage suffered by a possible pedestrian coming into contact with the vehicle, such as the hood.

[0052] In addition, said fluid pipe 5 advantageously has an elasticity of at least 60 Shore A (that is to say that the material in which said pipe is made has at least said elasticity characteristics).

[0053] Furthermore, the housing 9 is advantageously an open cavity formed directly in the absorber 3, the retaining section of which, i.e., the section in contact with the pipe 5, has, for example, a substantially circular cross-section (cross-section along an XZ plane in the mounted position). The shape of the retaining section of the housing 9 is advantageously the same along the entire length of the housing 9.

[0054] It will be noted that the shape of said section of the housing 9 generally has a shape similar or close to that of the pipe 5, in order to optimize the holding 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 to homogenize the pressure of the fluid in said pipe, without the pipe being crushed).

[0055] As particularly visible in [Fig.3], said housing 9 also includes pressure regulation means 11, among others mechanical, allowing the limitation of the occurrence of local overpressures, for example following incurvations or bends of the housing 9, and therefore of the pipe 5. It should be noted however that it is advantageous to provide regulation means 11 even in the absence of such geometries to allow more freedom of movement of said pipe 5 and to allow better homogeneity (or distribution) of the fluid pressure all along the pipe 5.

[0056] Thus, the regulating means 11 are advantageously openings lia or notches arranged in the walls of said housing 9 (and therefore the absorber 3), in particular at the level of the retaining section of housing 9 (that is to say the walls of housing 9 defining the retaining section of said pipe).

[0057] Said pressure regulating openings 1 are arranged alternately on opposite walls of said housing 9, such that said regulating means 1 have substantially a crenellated shape. It should be noted that "alternating openings" means that the openings 1 arranged on opposite walls of housing 9 are offset from one another (said opposite openings are not, or only partially, directly opposite each other).

[0058] Furthermore, said openings 1 of the pressure regulating means 11 are advantageously arranged regularly, that is to say, the distance between each opening 1a on a wall of the housing 9 is substantially identical. The distance between each opening 1a (between two consecutive openings located on the same wall) is, for example, less than 20 mm, and preferably less than 10 mm.

[0059] Furthermore, said regulating means 11 (and therefore openings 1a) are arranged as close as possible to said at least one bend of said pipe 5 (or housing 9), and advantageously in a straight portion of the pipe and / or housing.

[0060] Furthermore, by way of non-limitation, in the described embodiment, the curved portions of the pipe 5a and the housing 9a, more particularly visible in [Fig.4], are located at the ends 3a and 3b of said absorber 3, while the regulating means 11 are located in the middle area 3c of said absorber 3.

[0061] It should be noted that "arranged as close as possible" means that the regulating means are arranged just after and / or sufficiently close to a curved (or bent) portion to limit overpressures of the fluid in the pipe and preferably in a straight portion of the pipe.

[0062] Advantageously, said regulating means 11, and the openings 1a, are arranged at a distance of 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.

[0063] In addition, the system 1 advantageously includes for each curved portion 5a of the pipe 5a, associated pressure regulation means 11, the number of openings lia, the spacing between openings lia, etc. being for example a function of the radius of curvature of said curved portion 5a.

[0064] As more particularly visible in [Fig.5], said system 1 may also advantageously include means for retaining said pipe 5 in the housing 9 of the absorber 3.

[0065] The retaining means 15 are mechanical means, such as studs 15a (or protrusions) extending outwards into said housing 9, for example from the opposite walls of housing 9, and advantageously facing each other.

[0066] Furthermore, said studs 15a or protuberances are advantageously formed from material with the absorber 3. Said studs 15a are also preferentially located at the open longitudinal ends of the housing 9.

[0067] In an embodiment not shown, the retaining means 15 (and the pads 15a) are an added part and / or overmolded onto the absorber 3.

[0068] In another embodiment not shown, the pressure regulation means 11 are an added and / or overmolded part on the absorber 3, the absorber 3 having one or more recesses (or cavities) for disposing of said regulation means 11.

Claims

Demands

1. Collision detection system (1) for motor vehicle, said system (1) comprising: - a shock absorption device (3) having a housing (9); - at least two pressure sensors (7); - a fluid hose (5) each end of which is connected to one of said pressure sensors (7); said hose (5) being housed at least partially in the housing (9) of said absorption device (3), characterized in that said system (1) comprises means for regulating the pressure of the fluid of said hose (5), said pressure regulation means (11) comprising openings provided in the walls of the housing (9) housing said fluid hose (5).

2. System (1) according to the preceding claim, characterized in that said pressure regulation means (11) are mechanical means.

3. System (1) according to any one of the preceding claims, characterized in that said pressure regulating means (11) comprise openings (lia) arranged in the walls of the housing (9) housing said fluid pipe (5).

4. System (1) according to the preceding claim, characterized in that said openings (1 la) of the pressure regulation means are arranged alternately on opposite walls of said housing (9).

5. 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 disposed as close as possible to said at least one curved portion 5(a) of said pipe 5.

6. 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.

7. 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 between 40 g / L and 120 g / L.

8. System (1) according to any one of the preceding claims, characterized in that it comprises means for retaining said (15) 12 pipe (5) in the housing (9) of the shock absorption device (3).

9. System (1) according to the preceding claim, characterized in that said retaining means (15) are studs (15a) extending in projection into said housing (9).

10. Motor vehicle, characterized in that it comprises a collision detection system (1) according to any one of the preceding claims.