Flexible electro-resistive impact detection sensor for front carrier mounted airbag

Abstract

A measuring device for actuating an airbag system (35) for mitigating the indentation in the event of an offset impact with a rigid barrier (56) on a front corner of a motor vehicle (10), the airbag system (35) comprising a front motor vehicle support (16) with a forwardly projecting distal end (22), an airbag (36) attached near the distal end (22) of the front support (16), the airbag (36) having a stowed state and an inflated state, an inflator (62) operatively coupled to the airbag (36) and responsive to electrical actuation for inflating the airbag (36) with a gas, a flexible impact detection sensor (58, 74, 76) for generating a signal in the event of an impact, and a control unit (60) for processing the signal from the detection sensor (58, 74,76) and for electrically actuating the inflator (62) upon calculation of a predetermined impact severity at the front corner of the motor vehicle (10), wherein the airbag (36) in the inflated state acts against the offset rigid barrier (56) to generate a lateral force against the offset rigid barrier (56) to push the motor vehicle (10) away from the barrier (56) and thereby redirect the impact energy by lateral movement of the motor vehicle (10), wherein the measuring device is characterized in that the impact detection sensor (58, 74, 76), an electroresistive impact detection sensor (58, 74) and comprising a force-resistive film (78) having a conductive ink (80) printed on a transparent plastic membrane (82), and wherein the conductive ink (80) changes its resistance in response to the material stress occurring upon flexion of the plastic membrane (82), or a flexible fiber optic cable (92), a light source (94), a photodiode (96), and an amplifier (98), wherein the flexible fiber optic cable (92) has a core material (100) surrounded by a layer of cladding material (102) having a refractive index different from that of the core material (100), wherein the layer of cladding material (102) is modified to have bare sections (106) without cladding material (102) in a defined pattern, and wherein an amount of light detected by the photodiode (96) from the light source (94) through the flexible fiber optic cable (92) changes in response to the material stress occurring when the flexible fiber optic cable (92) is bent.

Description

[0001] The present invention relates generally to an airbag for a motor vehicle for minimizing indentation into the vehicle during an impact event, and more particularly to a front side member mounted airbag that is deployed to inflate and mitigate the impact of a small offset impact against a rigid barrier.

[0002] Airbag systems for use in motor vehicles are generally well known to those skilled in the art. Traditionally, such airbag systems have been used in the interior of motor vehicles to mitigate and reduce impacts of vehicle occupants against components and structural parts within the vehicle interior, such as steering wheels, instrument panels, knee bolsters, side door panels, and body pillars.

[0003] However, the present disclosure relates to the application of such airbag systems in combination with external components of the motor vehicle for managing and controlling impact events of the motor vehicle against external objects. In particular, the airbag system is designed to manage and control the impact event at the front corner of the motor vehicle. Therefore, numerous test protocols and standards have been and are being developed regarding vehicle integrity in the event of such a collision.For example, the Insurance Institute for Highway Safety (IIHS) has adopted a new small-offset frontal impact test, the test objective of which is to manage and control damage and injuries resulting from actual motor vehicle-to-stationary rigid pole impact events (offset from the motor vehicle's center of gravity and off-center from the main frame rail), collinear-offset vehicle-to-vehicle impact events (again offset from the motor vehicle's center of gravity), and oblique-angle vehicle-to-vehicle frontal impact events. The IIHS test protocol includes the evaluation of such rigid pole impact events and currently calls for a 25 percent overlapping rigid barrier with a rounded end simulating a 6-inch radius pole.The impact speed for the test is 40 mph (64 km / h). The test protocol under consideration will be referred to as the "SORB" (Small Offset Rigid Barrier Impact) 40 mph impact test.

[0004] As part of the SORB test protocol, current front-end structures are being evaluated to optimize vehicle behavior during impact events on small-offset piles. Therefore, solutions to mitigate SORB impact events would be beneficial.

[0005] DE 44 26 090 A1 discloses a safety system for a motor vehicle having protective devices such as extendable bumper parts, which can be triggered automatically via an evaluation unit connected to various distance sensors or manually by the driver or passenger. DE 10 2004 009 301 A1 discloses an impact sensing device having an acceleration sensor on the shock absorber. The acceleration sensor is arranged between the bumper and a bumper fascia. DE 198 18 586 C1, DE 102 17 031 A1, and DE 10 2008 038 062 B3 disclose further generic sensor devices.

[0006] The objective technical problem to be solved can be seen as eliminating or at least mitigating the disadvantages of the prior art. This problem is solved by the subject matter of the independent patent claims.

[0007] A measuring device according to the subject matter of patent claim 1 and a method according to the subject matter of patent claim 6 are provided.

[0008] In particular, the airbag assembly disclosed herein provides the described optimization of vehicle behavior by providing a deployable structure mounted on the vehicle's front side member behind the bumper. Upon vehicle impact with the SORB, a sensor mounted on the front bumper sends a signal to an electronic control unit, or ECU. Once the signal is processed, the ECU activates an inflator mounted on the side member, which deploys the airbag. The airbag design is configured such that the airbag deploys in a triangular shape, preferably creating a 30-degree angle between the longitudinal axis of the side member and the motor vehicle. The 30-degree angled end of the triangular deployed airbag is preferably located in close proximity to the vehicle's front bumper system.This deployment configuration allows the vehicle to generate a very high Y-force against the rigid barrier to push the vehicle away from the barrier, thus redirecting the impact energy through lateral movement of the vehicle and thereby minimizing vehicle crush.

[0009] According to one aspect of the present disclosure, an airbag system is disclosed that mitigates indentation in the event of an offset impact against a rigid barrier at a front corner of a motor vehicle. The airbag system includes a front motor vehicle beam having a forwardly projecting distal end and an airbag mounted proximate the distal end of the front beam, the airbag having a stowed condition and an inflated condition, wherein the airbag, in the inflated condition, has a leading edge inclined at an angle. An inflator is operatively coupled to the airbag and responsive to electrical actuation for inflating the airbag with a gas.An impact detection sensor generates a signal upon impact. A control unit processes the signal generated by the detection sensor and, after calculating a predetermined impact severity for the front corner of the vehicle, electrically actuates the inflator. The angled leading edge of the airbag, when inflated, acts against the offset rigid barrier, generating a lateral force against the offset rigid barrier to push the vehicle away from the barrier and thus redirect the impact energy through lateral movement of the vehicle.

[0010] Another aspect of the present disclosure is an airbag system having a pair of airbags, one of the pair of airbags being mounted on each side of the motor vehicle.

[0011] Another aspect of the present disclosure is an airbag system, wherein the motor vehicle has a front wheel mounted proximate the front support, and wherein the airbag is mounted forward of the front wheel.

[0012] Another aspect of the present disclosure is an airbag system, wherein the motor vehicle includes a body panel having an outer and an inner surface, the airbag disposed proximate the inner surface to act through the body panel to generate a lateral force against the offset rigid barrier.

[0013] Another aspect of the present disclosure is an airbag system utilizing an airbag having a substantially triangular configuration when inflated, wherein an angled leading edge corresponds to the hypotenuse of the triangular configuration, a leading end of the airbag corresponds to the apex of the triangular configuration, and a trailing end corresponds to the base of the triangular configuration.

[0014] Another aspect of the present disclosure is an airbag system wherein the apex of the triangular configuration has an angle of about 30 degrees.

[0015] Another aspect of the present disclosure is an airbag system, wherein the motor vehicle is equipped with an automatic occupant restraint system having a sensor for deploying the occupant restraint system, and the impact detection sensor is also the trigger sensor for the automatic occupant restraint system.

[0016] Another aspect of the present disclosure is an airbag system having an impact detection sensor mounted on an inner surface of the outboard portion of the front bumper.

[0017] An additional aspect of the present disclosure is an airbag system having an impact detection sensor that detects flexion of the outboard portion of the front bumper during the impact event.

[0018] Another aspect of the present disclosure is an airbag system having an impact detection sensor including a conductive foil that generates an electrical signal when flexed.

[0019] Yet another aspect of the present disclosure is an airbag system having a crash detection sensor comprising a fiber optic cable that generates a variable output signal in response to bending of the fiber optic cable.

[0020] Another aspect of the present disclosure is an airbag system for a motor vehicle comprising a front support, an airbag mounted on the front support, the airbag having an angled front edge when inflated, an inflator, a sensor for generating a signal upon impact of an object against the corner of the vehicle, and a controller for receiving the signal from the sensor and actuating the inflator, the angled front edge of the airbag generating a lateral force against the object.

[0021] And yet another aspect of the present disclosure is an airbag system using a front beam having a distal end and an outer surface, wherein the airbag is attached to the distal end of the front beam on the outer side surface of the front beam.

[0022] Another aspect of the present disclosure is an airbag system utilizing a pair of front beams extending forward from each side of the motor vehicle, with a pair of airbags mounted on each of the outer side surfaces thereof.

[0023] Yet another aspect of the present disclosure is a method of deploying an airbag system for generating a lateral force against an offset rigid barrier to urge the motor vehicle away from the barrier and thereby redirect impact energy through lateral movement of the motor vehicle, the method comprising the steps of: providing a front motor vehicle beam having a forwardly projecting distal end, securing an airbag proximate the distal end of the front beam, the airbag having a stowed condition and an inflated condition, the airbag in the inflated condition creating a sloped angled leading edge, providing the airbag with an inflator operatively coupled to the airbag and responsive to electrical actuation for inflating the airbag with a gas,Providing an impact detection sensor for generating a signal upon an impact event and providing a control unit for processing the signal generated by the detection sensor, electrically actuating the inflator at a predetermined impact severity on the front corner of the motor vehicle and presenting the inclined angled front edge of the airbag in the inflated state to act against the offset rigid barrier to generate a lateral force against the offset rigid barrier to push the motor vehicle away from the barrier and thereby redirect the impact energy through lateral movement of the motor vehicle.

[0024] Yet another aspect of the present disclosure is a method wherein the airbag, when inflated, has a substantially triangular configuration, wherein the angled leading edge of the hypotenuse corresponds to the triangular configuration, a leading end of the airbag corresponds to the apex of the triangular configuration having an angle of approximately 30 degrees, and a trailing end corresponds to the base of the triangular configuration.

[0025] These and other aspects, objects and features of the present disclosure will be understood and appreciated by those skilled in the art upon closer examination of the following description, claims and appended drawings.

[0026] The drawings show: Fig. 1 is a front perspective view of a front frame side member of a motor vehicle incorporating the first embodiment of the airbag for the airbag system according to the present disclosure in the inflated state; Fig. 2 is a rear perspective view of a front frame side member of a motor vehicle incorporating the first embodiment of the airbag for the airbag system according to the present disclosure in the inflated state; Fig. 3 is a bottom view of the first embodiment of the airbag for the airbag system of the present disclosure in the inflated state; Fig. 4 is a front view of the first embodiment of the airbag in the inflated state according to the present disclosure; Fig. 5 is a side view of the first embodiment of the airbag in the inflated state according to the present disclosure; Fig. 6 is a front perspective view of a second embodiment of the airbag in the inflated state according to the present disclosure; Fig. 7 is a plan view of the second embodiment of the airbag in the inflated state in contact with the impact barrier according to the present disclosure; Fig. 8 is a plan view of the second embodiment of the airbag in the stowed state according to the present disclosure; Fig. 9 is a rear perspective view of the first embodiment of the built-in bumper flexion impact sensor for use with the airbag system of the present disclosure; Fig. 10 is a top perspective view of the first embodiment of the bumper flexion impact sensor for use with the airbag system of the present disclosure; Fig. 11a is another perspective view of the first embodiment of the bumper flexion impact sensor for use with the airbag system of the present disclosure; Fig. 11b is another perspective view of the first embodiment of the bumper flexion impact sensor for use with the airbag system of the present disclosure; Fig. 12 is a schematic view of the second embodiment of the bumper flexion impact sensor for use with the airbag system of the present disclosure; Fig. 13 is a perspective view of the second embodiment of the bumper flexion impact sensor for use with the airbag system of the present disclosure; and Fig. 14 is a rear perspective view of the second embodiment of the built-in bumper flexion impact sensor for use with the airbag system of the present disclosure;

[0027] For the purposes of this description, the terms “upper”, “lower”, “right”, “left”, “rear”, “front”, “vertical”, “horizontal” and terms derived therefrom shall refer to the invention as described in Fig. 1. It is to be understood, however, that the invention is capable of various alternative orientations and sequences of steps unless expressly stated to the contrary. It is also to be understood that the specific devices and methods illustrated in the accompanying drawings and described in the following description are simply exemplary embodiments of the inventive concepts defined in the appended claims. Therefore, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered limiting unless expressly stated to the contrary in the claims.

[0028] Referring to Fig. 1-4, a motor vehicle 10 includes a front frame 12, including a pair of front beams 16 of the motor vehicle. In one embodiment of the present disclosure, the front frame 12 may extend substantially the length of the body, but in other configurations may extend outside and forward of a self-supporting body structure of the motor vehicle 10, as is typical in smaller vehicles. Each of the front beams 16 may have a beam configuration with integrated ribs 18 and flanges 20 for reinforcement, as shown in Fig. 1-8. The front supports 16 may also have a tubular configuration, as shown in Fig. 9 and Fig. 14. In both cases, each of the front beams 16 includes a front distal end 22 provided with a flange 24 to which a bumper assembly 26 may be attached, either directly or indirectly via an intermediate bumper bracket 28.

[0029] The bumper assembly 26 may take one of many possible configurations, but typically preferably includes a steel reinforcement beam 30 to which is attached an outer body panel 32 having a decorative finish and color-matched to the overall exterior color of the motor vehicle 10. The attachment of the bumper assembly 26 to the front beam 16 may also include a low-speed (i.e., 5-9 mph) impact absorber 154, such as a polygel absorber having a slidable piston and tube assembly capable of absorbing the impact energy of a low-speed impact without damage to the distal end 22 of the front beams 16 and with minimal damage to the outer body panel 32, as shown in FIGS. Fig. 9 and Fig. 14 shown.

[0030] The front beams 16, as well as other front body structures and engine components (in the case of motor vehicles with a front-mounted engine), have a deformable front portion 34 (which may also be used for impact absorption), as is already known. It is contemplated and intended that the front portion 34 will deform upon contact with an object in a forward collision, such as that in the NCAP test mentioned above, in order to absorb the impact energy associated with such a forward collision. As is common in such systems, one or more accelerometers are used as the sensing means to generate an electrical signal upon contact with the sudden negative acceleration in a frontal impact.This signal is then detected by the on-board electronic control unit or ECU 60 and then used to determine whether the built-in occupant restraint system, such as one or more airbag assemblies, should be deployed in the passenger compartment in the event that a predetermined negative acceleration is detected.

[0031] Further optimization of the structural vehicle behavior for SORB impact events can be achieved by providing a front beam-mounted airbag system 35 for mitigating the impact during a 40 mph SORB impact. An airbag 36 is attached, in the stowed state, to an outer surface 38 of the impact can ("bouncer") or a deformable segment 156 of the distal end 22 of the front side member 16, as best shown in Fig. 8. The front side member-mounted airbag 36, when stowed, preferably includes a number of predetermined folds 40, 42, 44, 46 for effecting deployment, as indicated below. Preferably, a pair of the front side member-mounted airbags 36 are positioned in front of each of the front wheels 48. In this manner, the front side member-mounted airbag 36 is secured to the front beam 16 of the motor vehicle 10 behind the front bumper assembly 26. In addition, the motor vehicle 10 may also include a front side body panel 50 for cosmetic purposes, such as the front fender shown in Fig. 7, having an outer surface 52 and an inner surface 54, with the airbag 36 disposed proximate the inner surface 54 and acting through the body panel 50 to generate a lateral force against the SORB barrier 56, as discussed below.

[0032] Upon a vehicle impact with the SORB barrier 56, a sensor 58 sends a signal to an electronic control unit or ECU 60. Once the signal is processed, the ECU 60 activates an inflator 62 operatively coupled to the front rail-mounted airbag 36, causing the front rail-mounted airbag 36 to deploy. The airbag 36 is preferably configured such that, when inflated, the airbag 36 deploys in a substantially triangular configuration, creating an angled leading edge 64 corresponding to the hypotenuse of the triangular configuration, a leading end 66 of the airbag corresponding to the apex of the triangular configuration and preferably having an angle of about 30 degrees, and a trailing end 68 corresponding to the base of the triangular configuration.This deployment configuration allows the vehicle to generate a very high lateral or Y-force against the SORB barrier 56, which propels the motor vehicle 10 laterally away from the SORB barrier 56, thus redirecting the impact energy through lateral movement of the motor vehicle 10 and thereby minimizing the crush of the motor vehicle, as best shown in FIG. Fig. 7 is shown.

[0033] As in Fig. 6-8, the front end 66 of the airbag may extend laterally outward to form an offset wall 70 to fill the space between the deployed airbag and the inner surface 54 of the front side panel 50. It is noted, however, that the angled front edge 64 is disposed at the same angle of approximately 30 degrees to the longitudinal axis of the motor vehicle to generate the Y-force necessary to move the motor vehicle 10 laterally. As further shown in Fig. 6, it may be helpful to mount the stowed airbag 36 in a frame 72, preferably made of steel or aluminum, to provide a reinforced space within which the airbag 36 can be inflated and thus maintain the shape of the angled leading edge 64 when deployed and coming into contact with the SORB barrier 56.

[0034] As previously indicated, accelerometers can be used as a sensing device to generate an electrical signal during sudden negative acceleration in a frontal impact, in order to deploy the passenger compartment airbag(s) when a predetermined negative acceleration is detected. These accelerometers can also be used to signal a vehicle impact with the SORB. However, under certain circumstances, such as small-overlap frontal impact events, the time required by conventional frontal impact detection systems may not be ideal and may not be sufficient to properly deploy the disclosed airbag structure.These types of impact events may require additional measurement systems specifically designed to capture small overlap frontal impact events, depending on the vehicle's frontal structure, impact speed, and the object involved in the impact.

[0035] Therefore, a separate sensor 58 mounted on the front bumper is preferably used to send a signal to the ECU 60 (as in Fig. 12) to inflate the airbag 36 upon impact with a SORB barrier 56, preferably within 5 to 15 milliseconds of the onset of the impact event. In fact, the front side member airbag 36 is preferably fully deployed and in position before the front beams 16 and impact can 154 begin to deform (approximately 10 to 20 milliseconds), depending on the front end structure of the vehicle. Therefore, in addition to conventional automotive impact sensors, a front bumper-mounted sensor 58 for determining deflection in the bumper reinforcement beam 30 may be employed to more quickly send a signal to the ECU 60 associated with the front bumper-mounted sensor 58 mounted on an outboard portion of the front bumper. This position provides an ideal signal for detecting the SORB impact event, regardless of the sensor design.However, this is a harsh environment, with temperatures reaching 105°C and salt spray from wheel spray when driving in rainy conditions. Two preferred concepts are one or more electroresistive beam flexure sensors 74 mounted on the front bumper beam, or one or more beam flexure sensors 76 on the front bumper based on fiber optic technologies.

[0036] The first concept, a flexible electroresistive sensor 74, is a flexible sensor design that monitors the flexion of the bumper reinforcement beam 30 located behind the front fascia 32. The flexible electroresistive sensor 74 includes a force-resistive film 78 consisting of a conductive ink 80 printed on a transparent plastic membrane 82. The conductive ink 80 changes resistance in response to the material stress that occurs when the membrane 82 flexes. By applying a voltage and measuring the change, the amount of flexion in the flexible electroresistive sensor 74 can be measured, as shown in Fig. 9. Thus, during an impact event, the membrane 82 flexes, generating an electrical signal from which the actual impact severity is measured and compared to the predetermined impact severity to determine whether deployment of the airbags 36 is required. If the deflected signal equals or exceeds a signal level corresponding to a predetermined impact severity, deployment of the airbag 36 is initiated. Because the flexible electroresistive sensor 74 operates at current levels that are insufficient to activate a communication protocol commonly used in automotive applications, the current level of the flexible electroresistive signal 74 must be increased in a separate step, after which the signal is output at a voltage level commonly used in automotive applications.

[0037] The flexible electroresistive sensor 74 is attached to a rear surface 31 of the outer portion 33 of the front bumper beam 30, forward of the front frame rail 16, to detect a small-displacement impact event that initially results only in bending of the outer portion 33 of the front bumper beam 30. Such bending only occurs when the impact is against an object with sufficient mass to bend the sheet metal bumper beam 30 and does not affect local, short-duration impact events that are highly resonant and do not result in significant displacement in the bumper beam 30. This improves the discrimination capability of the flexible electroresistive sensor 74 compared to an accelerometer, which also responds to oscillating signals resulting from vibrations.To provide a timely decision signal, the flexible electroresistive sensor 74 is preferably attached directly to a rear surface 31 of the outer portion 33 of the front bumper beam 30, as shown in FIG. Fig. 9. This mounting position is superior to mounting the front bumper beam electroresistive bending sensor 74 to the bumper fascia 32 in that the front bumper beam 30 is structurally more robust than the fascia 32 and will not bend during incidental impact events with low-mass objects such as shopping carts or bicycles.

[0038] In order for a flexible membrane sensor to function and survive in this environment, the force-resistive film sensor preferably uses a conductive ink 80 that retains its electrical properties at high temperatures (i.e., above 100°C). The flexible electroresistive sensor 74 is also preferably coated with a waterproof but flexible coating 86 to protect the ink 80 from water and salt spray, as shown in Fig. 10. The coating 86 may be a separate, solid piece wrapped around the flexible electroresistive sensor 74, or a tube surrounding the flexible electroresistive sensor 74 and sealed at the ends. The coating 86 may be applied to the flexible electroresistive sensor 74 using a dipping or spraying process. In this way, the coating 86 protects the flexible electroresistive sensor 74 from temperature extremes and contact with liquids that occur at the front bumper assembly 26. The materials for the coating 86 must be flexible enough that, when applied, they do not impair the flexural characteristics of the flexible electroresistive sensor 74.

[0039] Furthermore, the flexible electroresistive sensor 74 can be bonded to the metal of the bumper beam 30 with an adhesive such that the entire length of the flexible electroresistive sensor 74 is fixed and must expand and contract along with the bumper. However, the different thermal expansion coefficients of the ink 80 and membrane 82 of the force-resistive film sensor and the metal sheet of the front bumper beam 30 to which it is attached induce an inherent deviation in the signal during temperature changes, which can be significant compared to the output of the flexible electroresistive sensor 74 when flexed. To minimize this deviation, the flexible electroresistive sensor 74 is preferably attached at fixed points along its length. These can be wire clips 88 attached to the flexible electroresistive sensor 74 or integrated into the protective coating 86, as shown in Fig. 11a. However, this can also be a channel 90 that is rigidly attached to the bumper beam 30 or integrated into it, in which the flexible electroresistive sensor 74 lies loosely, as in Fig. 11b. Such an arrangement allows the elements of the flexible electroresistive sensor 74—ink 80, membrane 82, and coating 86—to thermally expand and contract independently of the thermal expansion and contraction of the front bumper beam 30, thereby reducing the amount of signal variation due to thermal cycling in the system. The flexible electroresistive sensor 74 can thus be used for the timely detection of SORB impact events. Furthermore, the flexible electroresistive sensor 74 is relatively inexpensive and environmentally robust, maintaining its sensing capabilities even in the presence of liquid mist and temperature changes.

[0040] Alternatively, a flexible fiber optic sensor 76 can be used to detect a SORB impact. The flexible fiber optic sensor 76 consists of a fiber optic cable 92, a light source 94, a photodiode 96, and an amplifier 98, as shown in Fig. 12. The light source 94, preferably an infrared light-emitting diode (LED), transmits a light signal through the fiber 92 of the fiber optic cable, which is received by the photodiode 96, preferably an infrared detector, which in turn outputs an electrical signal from an amplifier 98 proportional to the received light intensity "FS" and is passed to the control unit ECU 60.

[0041] The flexible fiber optic cable 92 consists of a core material 100 surrounded by a thin layer of cladding material 102 having a different refractive index than the core material 100. Normally, any light that bounces off the walls 104 of the core material 100 is reflected back into the core material 100, and no light is lost by bending the cable. However, if a portion of the cladding is removed, creating a bare section 106 on the core material 100, as shown in Fig. 13, a portion of the light that strikes the wall 104 of the core material 100 at an angle exits the core material 100. Bending the flexible fiber optic cable 92 allows even more light to escape. The amount of light incident on the photodiode 96 thus changes by decreasing it, and the signal from the photodiode 96 changes by decreasing it, thereby indicating how much the fiber optic cable 92 has been bent. Furthermore, if the jacket 102 is removed from only one side of the fiber optic cable 92, the photodiode 96 can be used to detect a directional signal indicating whether the fiber optic cable 92 is bending toward or away from the bare portion 106 of the modified side of the fiber optic cable 92.

[0042] As previously noted, the impact in the SORB test mode is preferably detected within 5 milliseconds of the initial contact to provide timely activation of the airbag 36 mounted on the front side member. By carefully positioning the fiber optic cable 92 in the relevant area and modifying the jacket 102 to create bare sections 106 in a defined pattern, the flexible optical sensor 76 can be configured to provide a signal for specifically detecting the SORB impact mode. As shown in Fig. 14, the fiber optic cable can be attached to the rear surface 31 of the outer portion 33 of the bumper reinforcement beam 30, as well as to the distal portion 22 of the frame rail 16 near the flange 24. In this configuration, the flexible optical sensor 76 measures any rearward flexion of the outer portion 33 of the front bumper assembly 26. To enable this specific mode, the jacket 102 is removed to form bare sections 106 in specific areas of the fiber optic cable 92. That is, the portion of the fiber optic cable 92 directly attached to the outer portion 33 of the front bumper reinforcement beam 30 preferably has the jacket 102 removed to form bare sections at regular intervals on one side to detect any local deformations of the bumper reinforcement beam 30 outside the frame rail 16.The jacket 102 is preferably removed to form bare sections 106 with smaller pitches in the bend radius to allow for timely indication of deformations between the bumper reinforcement beam 30 and the front side member 16 and flange 24. The jacket 102 is preferably removed only in those sections of the fiber optic cable 92 to form bare sections 106 on one side of the cable to distinguish between inward bending and outward bending.

[0043] Detection of the specific SORB impact mode of interest is accomplished by comparing the detected light intensity signal to a predetermined light intensity signal corresponding to an impact severity justifying airbag deployment, and deploying the airbag if the detected light intensity signal equals or exceeds the predetermined light intensity signal. The portion of fiber optic cable 92 attached to the front beam 16 has not had its jacket removed because the deformation of the front beam 16 occurs too late in the event to be useful for activation of the front side member airbag system 35. Using this selective jacket removal technique, a length of fiber optic cable 92 can be designed to perform timely bend detection in a specific orientation and direction.The optical cable sensor may be bonded with an adhesive to a rear surface of the front bumper beam substantially along the entire length of the sensor in contact with the bumper and the front beam. The fiber optic sensor may also be attached to the rear of the front bumper beam and to the distal portion of the front beam at fixed points along its length using wire clips 88 attached to the sensor, as shown in FIG. Fig. 11a shown.

[0044] The disclosed front beam-mounted SORB airbag system 35 is lightweight, has a minimal package size, and utilizes proven inflator technology. Furthermore, the disclosed front beam-mounted SORB airbag system 35 does not compromise efforts to optimize automotive vehicle performance in the NCAP (New Car Assessment Program) full frontal impact crash test at 35 mph. This means that the disclosed front beam-mounted SORB airbag system 35 can deploy in all cases where a frontal impact component may be present (e.g., full frontal impact, offset frontal impact, and angled impact). While a SORB impact event may also be detected by conventional frontal impact sensors, causing restraint systems to deploy in frontal collisions, separate sensors 58 mounted on the front bumper reinforcement beam provide improved performance.

Claims

[1] A measuring device for actuating an airbag system (35) for mitigating the indentation in the event of an offset impact with a rigid barrier (56) on a front corner of a motor vehicle (10), the airbag system (35) comprising a front motor vehicle support (16) with a forwardly projecting distal end (22), an airbag (36) attached near the distal end (22) of the front support (16), the airbag (36) having a stowed state and an inflated state, an inflator (62) operatively coupled to the airbag (36) and responsive to an electrical actuation for inflating the airbag (36) with a gas, a flexible impact detection sensor (58, 74, 76) for generating a signal in the event of an impact event, and a control unit (60) for processing the signal from the detection sensor (58, 74,76) and for electrically actuating the inflator (62) upon calculation of a predetermined impact severity at the front corner of the motor vehicle (10), wherein the airbag (36) in the inflated state acts against the offset rigid barrier (56) to generate a lateral force against the offset rigid barrier (56) to push the motor vehicle (10) away from the barrier (56) and thereby redirect the impact energy by lateral movement of the motor vehicle (10), wherein the measuring device , characterized by is that the impact detection sensor (58, 74, 76) an electroresistive impact detection sensor (58, 74) and comprising a force-resistive film (78) having a conductive ink (80) printed on a transparent plastic membrane (82), and wherein the conductive ink (80) changes its resistance in response to the material stress occurring upon flexion of the plastic membrane (82), or a flexible fiber optic cable (92), a light source (94), a photodiode (96), and an amplifier (98), wherein the flexible fiber optic cable (92) has a core material (100) surrounded by a layer of cladding material (102) having a refractive index different from that of the core material (100), wherein the layer of cladding material (102) is modified to have bare sections (106) without cladding material (102) in a defined pattern, and wherein an amount of light detected by the photodiode (96) from the light source (94) through the flexible fiber optic cable (92) changes in response to the material stress occurring when the flexible fiber optic cable (92) is bent. [2] Measuring device according to claim 1, wherein a front bumper beam (30) is attached to the distal end (22) of the front beam (16) and the sensor (58, 74, 76) is attached to an outer part (33) of the bumper (30) and is designed to measure the bending in the bumper (30). [3] Measuring device according to claim 2, wherein the sensor (58, 74, 76) is attached directly to a rear side of the front bumper beam (30). [4] Measuring device according to claim 3, wherein the sensor (58, 74, 76) is attached to a rear surface (31) of the front bumper beam (30). [5] Measuring device according to claim 3, wherein the sensor (58, 74, 76) is attached at fixed points along its length to a rear surface (31) of the front bumper beam (30). [6] Method for deploying an airbag system (35) in a motor vehicle (10), the method comprising the following steps: Providing a front motor vehicle carrier (16) having a distal end (22) projecting forward; Providing an airbag (36) having a stowed state and an inflated state; Equipping the airbag (36) with an inflator (62) operatively coupled to the airbag (36) and responsive to electrical actuation to inflate the airbag (36) with a gas; Providing a flexible impact detection sensor (58, 74, 76) for generating a signal in response to an offset impact event; Providing a control unit (60) for processing the signal generated by the detection sensor (58, 74, 76); and Electrically actuating the inflator (62) upon a predetermined impact severity on the vehicle (10), whereby the procedure characterized by is that the impact detection sensor (58, 74, 76) an electroresistive impact detection sensor (58, 74) and comprising a force-resistive film (78) having a conductive ink (80) printed on a transparent plastic membrane (82), and wherein the conductive ink (80) changes its resistance in response to the material stress occurring upon flexion of the plastic membrane (82), or a flexible fiber optic cable (92), a light source (94), a photodiode (96), and an amplifier (98), wherein the flexible fiber optic cable (92) has a core material (100) surrounded by a layer of cladding material (102) having a refractive index different from that of the core material (100), wherein the layer of cladding material (102) is modified to have bare sections (106) without cladding material (102) in a defined pattern, and wherein an amount of light detected by the photodiode (96) from the light source (94) through the flexible fiber optic cable (92) changes in response to the material stress occurring when the flexible fiber optic cable (92) is bent. [7] The method of claim 6, further comprising the steps of applying a voltage to the electroresistive sensor (58, 74) and measuring the amount of deflection in the electroresistive film sensor (58, 74) to determine the amount of deflection in the bumper (30). [8] The method of claim 6, wherein the method for the electroresistive sensor (58, 74) further comprises the step of comparing the actual impact severity to the predetermined impact severity and deploying the airbag (36) when the impact severity equals or exceeds the predetermined impact severity.

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