Patent Publication Number: US-2015074969-A1

Title: Integrated passenger airbag

Description:
FIELD OF THE INVENTION 
     The present invention generally relates to an airbag for a motor vehicle to optimize occupant protection during a frontal impact event, specifically an integrated airbag mounted in the instrument panel that is triggered to inflate in the event of and to mitigate frontal impacts to restrain the torso, head, and lower extremities of a motor vehicle passenger. 
     BACKGROUND OF THE INVENTION 
     Improving the crashworthiness of motor vehicles has long been the goal of automobile manufacturers and policymakers. In the United States, Federal Motor Vehicle Safety Standard (FMVSS) No. 208 was promulgated to encourage improved occupant responses to frontal impact events. In sum, FMVSS 208 presently requires that a simulated vehicle occupant experience head and thoracic de-accelerations and right and left femur loads within specified limits following a motor vehicle impact with a rigid barrier at an impact velocity of 35 MPH. Additionally, the National Highway and Traffic Administration conducts its New Car Assessment Program (NCAP), which reports the results of its testing to the public based on the testing conducted according to the procedures of FMVSS 208. 
     In view of such testing protocols, front end structures have been optimized to meet frontal safety requirements in such frontal impact events. That is, techniques have been adopted to absorb the kinetic energy from such frontal impacts and reduce the severity of the secondary impact that potentially occurs between the motor vehicle occupant and the interior components of the passenger compartment. In addition to engineered structures for front end components, such as the engine compartment, hood, fenders, and front wheel suspension and undercarriage components, occupant restraints have been employed. Such occupant restraint systems, particularly for front passengers, include adaptive seatbelts, energy absorbing glove boxes, and airbag systems. 
     Airbag systems for use in motor vehicles are generally well-known in the art. 
     Traditionally, such airbag systems have been used within motor vehicle interiors to mitigate and reduce occupant impacts with motor vehicle interior components and structures, such as steering wheels, instrument panels, knee bolsters, glove boxes, side door panels, and body pillars. Such airbag systems are designed to deploy very quickly upon detection of the impact event, depending on its severity. 
     In the adoption of frontal impact airbags, however, it is sometimes necessary to utilize two separate airbags to restrain the motor vehicle occupant to obtain optimal test results within the specified criteria. In particular, in the case of a front seat passenger position, a first passenger airbag is often mounted in an upper portion of the instrument panel and, when inflated, engages the torso and head of the passenger. A separate second knee airbag may be mounted in a lower portion of the instrument panel and, when inflated, engages the lower extremities, in particular, the knees of the passenger, to reduce loading on the occupant&#39;s femurs. However, the use of a separate knee airbag incurs additional cost, complexity, and weight. For example, additional structural steel is required to attach the knee airbag to the instrument panel and provide appropriate reinforcement. Hence, solutions for obtaining acceptable simulated occupant responses, particularly femur loads, without use of a separate knee airbag would be advantageous. 
     The airbag assembly disclosed herein particularly accomplishes the foregoing optimization of simulated occupant response to a frontal impact event by providing an integrated airbag mounted on the upper portion of the instrument panel. The integrated airbag in the inflated condition has a main airbag portion defining an upper chamber and a lower extended portion defining a chamber depending from the main airbag portion. The main airbag portion in the inflated condition acts against the head and torso of the motor vehicle occupant so as to generate a restraining force against the head and torso of the motor vehicle occupant, and the lower extended portion in the inflated condition acts against the pair of knees of the motor vehicle occupant so as to mitigate femur forces on the knees of the motor vehicle occupant. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the present disclosure, an integrated airbag system is disclosed for mitigating motor vehicle occupant injuries in the event of a high speed impact of a motor vehicle with a frontal rigid barrier or other structure disposed in front of the motor vehicle. The motor vehicle includes an occupant compartment having a forward facing seat upon which an occupant is supported and a panel disposed in front of and facing the forward facing seat, wherein the panel has an upper portion and a lower portion. The airbag system includes an integrated airbag mounted on the panel, the integrated airbag having a stowed condition and an inflated condition. The integrated airbag in the inflated condition has a main airbag portion defining an upper chamber and a lower extended portion defining a chamber depending from the main airbag portion in fluid communication with the main airbag portion. An inflator is operationally coupled with the integrated airbag and is responsive to electrical actuation for inflating the integrated airbag with a gas. An impact detection sensor generates a signal upon an impact event, and a controller processes the signal generated by the detection sensor and electrically actuates the inflator upon computing a predetermined impact severity to the motor vehicle, wherein the main airbag portion in the inflated condition acts against the head and torso of the motor vehicle occupant so as to generate a restraining force against the motor vehicle occupant and the lower extended portion in the inflated condition acts against the pair of knees of the motor vehicle occupant so as to mitigate the femur forces on the knees of the motor vehicle occupant generated by contact with the lower portion of the panel during the impact event. 
     Still another aspect of the present disclosure is an airbag system wherein the forward facing seat is a front seat of the motor vehicle, the motor vehicle occupant is the front seat passenger, and the panel is the motor vehicle instrument panel. 
     Yet another aspect of the present disclosure is an airbag system wherein the occupant compartment includes a windshield disposed adjacent and above the instrument panel that in part defines an upper space amid the head and torso of the motor vehicle occupant, the windshield, and the instrument panel, wherein the main airbag portion in the inflated condition substantially fills the upper space amid the head and torso of the motor vehicle occupant, the windshield, and the instrument panel. 
     An additional aspect of the present disclosure is an airbag system wherein the lower portion of the instrument panel in part defines a lower gap between the knees of the motor vehicle occupant and the instrument panel, wherein the lower extended portion in the inflated condition substantially fills the lower gap between the knees of the motor vehicle occupant and the lower portion of the instrument panel. 
     Another aspect of the present disclosure is an airbag system utilizing an integrated airbag mounted within a recess provided in the instrument panel. 
     Still another aspect of the present disclosure is an airbag system wherein the integrated airbag is mounted in the upper portion of the instrument panel. 
     A further aspect of the present disclosure is an airbag system wherein the femur loading on the motor vehicle occupant during the impact event is initially in tension, while subsequent femur loads are in compression. 
     Another aspect of the present disclosure is an airbag system wherein the lower extended portion is inflated subsequent to the inflation of the main airbag portion. 
     Yet a further aspect of the present disclosure is an airbag system wherein the main airbag portion defines a substantially spherical chamber, and the lower extended portion defines a substantially rectangular chamber. 
     An additional aspect of the present disclosure is an integrated airbag for mitigating occupant injuries in the event of a frontal impact comprising a main portion, a lower extended portion depending from the main portion, and an inflator mounted in a panel, wherein the main portion when inflated acts against the head and torso of the occupant, and the lower extended portion when inflated acts against the occupant&#39;s knees to mitigate the femur forces on the knees generated by contact with the panel during the impact. 
     Yet another aspect of the present disclosure is an airbag system wherein the main portion of the airbag defines a substantially spherical chamber, and the lower extended portion defines a substantially rectangular chamber depending from the main airbag portion. 
     A still further aspect of the present disclosure is a method of employing an airbag system to generate a resistive force against a motor vehicle occupant in the event of a high speed impact of a motor vehicle with a frontal rigid barrier or other structure disposed in front of the motor vehicle to restrain the motor vehicle occupant from impact with interior components of the motor vehicle is disclosed, as set forth above. The method includes the steps of providing an occupant compartment with a forward facing seat upon which an occupant is supported and an instrument panel disposed in front of and facing the front seat, wherein the instrument panel has an upper portion and a lower portion. The integrated airbag, when in the inflated condition, has a main airbag portion defining an upper chamber, and a lower extended portion defining a chamber depending from the main airbag portion. The impact detection sensor is mounted in the motor vehicle for generating a signal upon a frontal impact event proximate the front of the motor vehicle and providing the signal to a controller. An inflator is operationally coupled with the integrated airbag responsive to electrical actuation for inflating the integrated airbag with a gas when the controller computes a predetermined impact severity to the motor vehicle. The main airbag portion is inflated to act against the head and the torso of the motor vehicle occupant so as to generate a restraining force against the motor vehicle occupant, while the lower extended portion is inflated to act against the pair of knees of the motor vehicle occupant so as to mitigate the femur forces on the knees of the motor vehicle occupant generated by contact with the lower portion of the instrument panel during the impact event. 
     Another aspect of the present disclosure is a method of employing an airbag system wherein the lower extended portion is inflated subsequent to the inflation of the main portion. 
     A yet additional aspect of the present disclosure is a method of employing an airbag system wherein the main airbag portion defines a substantially spherical chamber, and the lower extended portion defines a substantially rectangular chamber. 
     These and other aspects, objects, and features of the present disclosure will be understood and appreciated by those skilled in the art upon studying the following specification, claims, and appended drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings: 
         FIG. 1  is a side view of the passenger airbag of the prior art in the inflated condition; 
         FIG. 2  is a side view of the passenger airbag and separate knee airbag of the prior art in the inflated condition; 
         FIG. 3  is a side view the integrated passenger airbag in the inflated condition in accordance with the present disclosure; 
         FIG. 4  is a perspective front view of the integrated passenger airbag in the inflated condition in accordance with the present disclosure; 
         FIG. 5  is a graphical representation comparing the expected right femur loads with no knee airbag provided, with a separate knee airbag provided, and with an integrated airbag in accordance with the present disclosure; and 
         FIG. 6  is a graphical representation comparing the expected left femur loads with no knee airbag provided, with a separate knee airbag provided, and with an integrated airbag in accordance with the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     For purposes of description herein, the terms “upper,” “lower,” “right,” “left,” “rear,” “front,” “vertical,” “horizontal,” and derivatives thereof shall relate to the invention as oriented in  FIG. 1 . However, it is to be understood that the invention may assume various alternative orientations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification, are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise. 
     Referring to  FIGS. 1-4 , a motor vehicle  10  includes an interior occupant compartment  12  including a front seat assembly  14  and an instrument panel  16 , the occupant compartment  12  being defined in part by a windshield  18  and a roof portion  20 . The occupant  22 , in particular a front seat passenger, is supported by the front seat assembly  14 . The front seat assembly  14  is typically configured to move forward and rearward. The front seat occupant  22  is primarily restrained by a front passenger seat belt assembly  24  having a belt web  26 , a lower detachable mount  28  attached to the inboard of the front seat assembly  14 , an upper seat belt ring  30  on the so-called B-pillar  32  through which the belt web  26  passes, and a lower housing  34  within which a web reel and an inertial clutch assembly  36  is mounted that restrains the belt web  26  from further deploying in the event of a frontal crash event. However, it should be noted that the occupant  22  may be belted or unbelted and still obtain the benefits of the improvement of the present disclosure. 
     Additional occupant protection may be provided by a standard passenger airbag  38 , without the improvement disclosed herein, as shown in  FIG. 1 . The passenger airbag  38  is mounted on the upper surface  40  of the instrument panel  16 , proximate the windshield  18  and facing upwardly and toward the front seat occupant  22 , and is disposed to actuate upon a frontal impact of a predetermined severity. That is, upon vehicle impact with a rigid barrier (not shown), a sensor  42  sends a signal to an electronic control unit  44  or ECU. Once the signal is processed, the ECU  44  actuates an inflator  46  operationally coupled with the front passenger airbag  38  to deploy the front passenger airbag  38 . The passenger airbag  38 , typically constructed from nylon or polyester, is configured such that the passenger airbag  38  will deploy in a substantially spherical configuration when in the inflated condition to substantially fill the space within the occupant compartment  12  below the windshield  18  proximate the instrument panel  16  and in front of the occupant  22 , thereby creating a relatively compliant surface  48  against which the torso  50  and head  52  of the occupant  22  are restrained during an impact event. 
     However, while the passenger airbag  38  shown in  FIG. 1  has proven to be extremely effective in obtaining compliance with the head and thoracic de-acceleration criteria in simulated vehicle occupant responses, such a passenger airbag  38  is not itself effective in mitigating the right and left femur loads within the specified limits following a motor vehicle impact with a rigid front barrier at an impact velocity of 35 MPH. For this purpose, energy absorbing knee bolsters  56  have been employed, as seen in  FIG. 1 . 
     Another solution for mitigating the right and left femur loads within the specified limits has been the adoption of a separate, second knee airbag  58  mounted in a lower portion  60  of the instrument panel  16  that, when inflated, engages the lower extremities, in particular, the knees  62  of the occupant  22 , to reduce loading on the occupant&#39;s femurs  64 , as shown in  FIG. 2 . However, the use of a separate knee airbag  58  incurs additional cost, complexity, and weight. For example, additional structural steel is required to attach the separate knee airbag  58  to the instrument panel  16  and to provide appropriate reinforcement. A separate knee airbag  58  also consumes valuable space within the instrument panel and requires separate sensor loops for the airbag electronics. That is, the use of a separate knee airbag  58  requires two inflators  46  and  66 , one for the passenger airbag  38  and one for the knee airbag  58 , in order to provide optimized protection for an occupant&#39;s torso  50 , head  52 , and lower extremities, such as knees  62  and femurs  64 . Two airbags, two igniters, and duplicate related circuitry are required. 
     The integrated airbag  68  of the present disclosure provides an effective in-position airbag deployment solution to the airbag systems of the prior art. The disclosed integrated airbag  68 , also constructed of nylon or polyester, is mounted in a recess  70  located on the upper portion  40  of the instrument panel  16  in the stowed condition. The integrated airbag  68  has a main airbag portion  72  when in the inflated condition. The main airbag portion  72  defines an upper chamber that substantially fills an upper space defined by the windshield  18  disposed adjacent and above the instrument panel  16 . Preferably, the main airbag portion is substantially spherical, as shown, so as to efficiently fill the upper space. However, other shapes can be adopted, such as triangular, rectangular, elliptical, or trapezoidal. The main airbag portion  72  thus acts against the torso  50  and head  52  of the occupant  22  in the inflated condition so as to generate a restraining force against the occupant  22 . 
     The integrated airbag  68  of the present disclosure also has a lower extended portion  74  defining a chamber depending from the main airbag portion  72  and in fluid communication with the main airbag portion  72 , as shown in  FIGS. 3 and 4 . The lower portion  60  of the instrument panel  16  in part defines a lower gap G between the knees  62  of the motor vehicle occupant  22  and the lower portion  60  of the instrument panel  16 , wherein the lower extended portion  74  in the inflated condition substantially fills the lower gap G between the knees  62  of the motor vehicle occupant  22  and the instrument panel  16 . Preferably, the lower extending portion  74  is substantially rectangular, as shown. However, other shapes can be adopted, such as triangular, elliptical, or trapezoidal, so long as the gap G is filled. 
     The lower extended portion  74  thus acts against the pair of knees  62  of the motor vehicle occupant  22  in the inflated condition so as to reduce the femur forces on the knees of the knees  62  of the occupant  22  generated by contact with the lower portion  60  of the instrument panel  16  during an impact event. Preferably, the width of the lower extended portion  74  is sufficient to ensure contact with the lower extended portion  74  by both knees  62  of the occupant  22 . Similarly, the depth of the lower extended portion  74  is preferably sufficient to ensure vertical contact with the lower extended portion  74  by the knees  62  of the 5 th  percentile prototypical female occupant, the 50 th  percentile prototypical male occupant, and the 95 th  percentile prototypical large male occupant. 
     As above, an inflator  46  is operationally coupled with the integrated airbag  68  and is responsive to electrical actuation for inflating the integrated airbag  68  with a gas, such as sodium azide, when an impact detection sensor  42  generates a signal upon an impact event and directs the signal to a controller  44  for processing the signal generated by the detection sensor  42  upon computing a predetermined impact severity to the motor vehicle  10 . 
     The disclosed integrated airbag  68  is believed to provide unique occupant protection for the lower extremities of the motor vehicle occupant  22 . As shown in the simulations depicted in  FIGS. 5-6 , the peak femur  64  loads for the passenger airbag  38  acting against only the occupant&#39;s torso  50  and head  52  in combination with a knee bolster  56  is expected to be nearly three times higher than that of the passenger airbag  38  acting against the occupant&#39;s torso  50  and head  52  in combination with a separate knee airbag  58 . In further comparison, due to the configuration of the integrated airbag  68  of the present disclosure, the lower extended portion  74  is inflated subsequent to the inflation of the main airbag portion  72 . As a consequence, the torso  50  and head  52  of the occupant  22  are initially restrained, while the lower extremities of the occupant  22  tend to move forward due to inertia. Subsequently, the lower extended portion  74  is deployed and begins to act against the knees  62  of the occupant  22 . Accordingly, the initial loading experienced by the occupant&#39;s femur  64  during an impact event is such that the initial femur  64  load is in tension and subsequent femur  64  loads are in compression, as shown in  FIGS. 5-6 , with the peak femur  64  loads comparing favorably with those experienced with the passenger airbag  38  acting against the occupant&#39;s torso  50  and head  52  in combination with a separate knee airbag  58 , but without the cost and complexity associated with a separate knee airbag  58 . 
     Thus, a cost-effective method of employing an airbag system to generate a resistive force against a motor vehicle occupant  22  in the event of a high speed impact of a motor vehicle  10  with a frontal rigid barrier or other structure disposed in front of the motor vehicle  10  to restrain the occupant  22  from impact with interior components of the motor vehicle  10  is disclosed, as set forth above. In operation, an integrated airbag  68  is provided within an occupant compartment  12  provided with a forward facing seat  14  upon which an occupant  22  is supported and an instrument panel  16  disposed in front of and facing the front seat  14 , wherein the instrument panel  16  has an upper portion  40  and a lower portion  60 . The integrated airbag  68  has a main airbag portion  72  preferably defining a substantially spherical chamber and a lower extended portion  74  preferably defining a substantially rectangular chamber depending from the main airbag portion  72 . The impact detection sensor  42  mounted in the motor vehicle  10  generates a signal upon a frontal impact event proximate the front of the motor vehicle  10  and provides the signal to a controller  44 . An inflator  46  is operationally coupled with the integrated airbag  68  responsive to electrical actuation for inflating the integrated airbag  68  with a gas when the controller  44  computes a predetermined impact severity to the motor vehicle  10 . The main airbag portion  72  is inflated to act against the torso  50  and head  52  of the occupant  22  so as to generate a restraining force against the occupant  22 , while the lower extended portion  74  is inflated to act against the pair of knees  62  of the occupant  22  so as to reduce the femur forces on the knees  62  of the occupant  22  generated from contact with the lower portion  60  of the instrument panel  16  during an impact event. 
     The integrated airbag  68  of the present disclosure provides uniform restraint to occupant&#39;s torso  50 , head  52 , and knees  62 . In addition, the integrated airbag  68  has the advantage of using a single module to protect the occupant&#39;s torso  50 , head  52 , and lower extremities. The integrated frontal impact airbag system disclosed herein is lightweight, requires minimum packaging, and utilizes well-proven inflator technology. Further, the disclosed integrated frontal impact airbag system avoids the additional cost, complexity, and weight of a separate knee airbag. For example, the additional structural steel required to attach the separate knee airbag  58  to the instrument panel  16  and to provide appropriate reinforcement, as well as the duplicate sensor loops for the separate knee airbag  58 , is completely avoided. 
     It is to be understood that variations and modifications can be made on the aforementioned structure without departing from the concepts of the present invention, and further it is to be understood that such concepts are intended to be covered by the following claims unless these claims by their language expressly state otherwise.