Abstract:
An airbag module for protecting an occupant of a vehicle includes an airbag including an inflatable portion and an inflator for providing inflation gas for inflating the inflatable portion of the airbag. The airbag includes a non-inflatable portion located within the inflatable portion so that in the longitudinal direction of the vehicle the non-inflatable portion is bounded on both sides by the inflatable portion of the airbag and wherein the non-inflatable portion extends the entire cross vehicle width of the airbag. The airbag is configured to inflate into a position so that a surface of the airbag faces the occupant. The stiffness of the inflatable portion varies along the surface facing the occupant based on a changing distance from the surface to the non-inflatable portion.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to and the benefit of U.S. Provisional Application No. 61/213,674, filed Jul. 1, 2009, the entirety of which is herein incorporated by reference. 
    
    
     BACKGROUND 
     The present disclosure relates generally to the field of airbags for use in motor vehicles. More specifically, this disclosure relates to an airbag having a non-inflated portion, upon deployment, to tailor the restraint forces, which may vary along different portions of the airbag, to reduce the likelihood of injury of the occupant. 
     Airbags are one type of restraint system typically located in vehicles to protect occupants from injury during a vehicle dynamic impact event. Typical restraint systems include sensors located in the vehicle to initiate deployment of the airbag. An airbag may deploy and inflate, by gas rapidly entering the airbag, typically through the use of an inflator containing an explosive charge (e.g., pyrotechnic device). Passenger airbags are typically stored within and deployed from the vehicle dashboard or instrument panel, and are typically packaged through a process of folding and rolling to compact the airbag in order to minimize its required packaging space. During a vehicle dynamic impact event, a passenger airbag may deploy from the upper portion (i.e., above the glove box) of the dashboard, in substantially rearward and upward directions to protect the head and torso of the occupant. A passenger airbag may also deploy from the rear facing portion of the dashboard in substantially a rearward direction towards the occupant. Driver airbags are typically stored within the steering column and are typically packaged through a process of folding and rolling to compact the airbag in order to minimize its required packaging space. During a vehicle dynamic impact event, a driver airbag may deploy in substantially a rearward direction towards the driver to protect the head and torso of the driver. 
     It has been known to construct a vehicle to include an airbag having a single chamber whereby the gas generated by an inflator is directly forced into the airbag chamber, unfolding and expanding the airbag chamber to provide protection to the vehicle occupant during a vehicle impact. This method of air bag construction may involve mounting the air bag on the top facing surface of the dashboard or on the rear facing surface of the dashboard. It has also been known to construct a bi-lobular air bag, which comprises of a single chamber having two side by side lobes separated by a gap or void, but each lobe being directly inflated by the inflator. These methods of construction have several disadvantages, the key disadvantage being that during deployment of the air bag, each lobe will have substantially similar expansion forces, therefore exerting substantially uniform restraint forces onto all areas of contact with the occupant. 
     It would be advantageous for an airbag to be constructed to include at least one non-inflated portion (or volume), whereby the size, shape, and location of the non-inflated portion may be configured to tailor the reaction (or restraint) forces from the different portions of the airbag. An airbag having tailored restraint forces, during deployment, may mitigate occupant injury by providing restraint forces optimized for different regions of the occupant (e.g., head and neck regions), according to the varying mass of the different regions of the occupant (e.g., the head has a lower mass than the torso of an occupant). This configuration would provide optimized occupant protection and reduce head and neck injuries. 
     SUMMARY 
     According to one exemplary embodiment, an airbag module for protecting an occupant of a vehicle includes an airbag including an inflatable portion and an inflator for providing inflation gas for inflating the inflatable portion of the airbag. The airbag includes a non-inflatable portion located within the inflatable portion so that in the longitudinal direction of the vehicle the non-inflatable portion is bounded on both sides by the inflatable portion of the airbag and wherein the non-inflatable portion extends the entire cross vehicle width of the airbag. The airbag is configured to inflate into a position so that a surface of the airbag faces the occupant. The stiffness of the inflatable portion varies along the surface facing the occupant based on a changing distance from the surface to the non-inflatable portion. 
     According to another exemplary embodiment, an airbag module for protecting an occupant of a vehicle includes an airbag including an inflatable portion and an inflator for providing inflation gas for inflating the inflatable portion of the airbag. The airbag includes a non-inflatable portion located within the inflatable portion. The non-inflatable portion extends the entire cross vehicle width of the airbag. The airbag is configured to inflate into a position so that a surface of the airbag faces the occupant. A volumetric ratio of a volume of a space enveloped by the inflatable portion to a volume of the inflatable portion only is greater than or equal to 1.2. 
     According to another exemplary embodiment, an airbag module for protecting an occupant of a vehicle includes an airbag including an inflatable portion and an inflator for providing inflation gas for inflating the inflatable portion of the airbag. The airbag includes a non-inflatable portion located within the inflatable portion so that in the longitudinal direction of the vehicle the non-inflatable portion is bounded on both sides by the inflatable portion of the airbag. The non-inflatable portion extends the entire cross vehicle width of the airbag. The airbag is configured to inflate into a position so that a surface of the airbag faces the occupant. The inflatable portion includes first and second fluidly connected inflatable chambers by a flow restricting channel. The second inflatable chamber is located adjacent to the surface of the airbag facing the occupant. Inflation gas enters the second inflatable chamber after passing through the first inflatable chamber and the flow restricting channel so that after initiation of the inflator and prior to completion of the inflation of the airbag the stiffness of the airbag at a point on the surface adjacent the second inflatable chamber is less than the stiffness of the airbag at a point on the surface adjacent the first inflatable chambers. 
     According to another exemplary embodiment, an airbag module for protecting an occupant of a vehicle includes an airbag including an inflatable portion and an inflator for providing inflation gas for inflating the inflatable portion of the airbag. The airbag includes a low pressure inflatable portion located within the inflatable portion so that in the longitudinal direction of the vehicle the low pressure inflatable portion is bounded on both sides by the inflatable portion of the airbag. The low pressure inflatable portion extends the entire cross vehicle width of the airbag. The airbag is configured to inflate into a position so that a surface of the airbag faces the occupant. The inflatable portion includes first and second fluidly connected inflatable chambers by a flow restricting channel. The second inflatable chamber is located adjacent to the surface of the airbag facing the occupant. Inflation gas enters the second inflatable chamber after passing through the first inflatable chamber and the flow restricting channel. The second inflatable chamber includes a vent to allow inflation gas to escape from the second inflatable chamber into the low pressure inflatable chamber so that low pressure inflatable chamber inflates to a pressure less than the first and second inflatable chambers. 
     According to another exemplary embodiment, an airbag module for protecting an occupant of a vehicle includes an airbag including an inflatable portion and an inflator for providing inflation gas for inflating the inflatable portion of the airbag. The airbag includes a non-inflatable portion located within the inflatable portion so that in the longitudinal direction of the vehicle and in the cross vehicle direction the non-inflatable portion is bounded on all four sides by the inflatable portion of the airbag. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only, and are not restrictive of the invention as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features, aspects, and advantages of the present invention will become apparent from the following description, appended claims, and the accompanying exemplary embodiments shown in the drawings, which are briefly described below. 
         FIG. 1  is a perspective view of a motor vehicle, according to an exemplary embodiment. 
         FIG. 2  is a perspective view of the interior passenger compartment of a motor vehicle that includes a passenger air bag integrated into the dashboard, according to an exemplary embodiment. 
         FIG. 3  is a cross-car section view of the interior passenger compartment of  FIG. 2 , taken along line  3 - 3 , illustrating the airbag assembly in the folded or undeployed state, according to an exemplary embodiment. 
         FIG. 4  is a cross-car partial section view of the interior passenger compartment of  FIG. 3  illustrating the airbag assembly with a non-inflated portion, shown in an unfolded or deployed state, according to an exemplary embodiment. 
         FIG. 5   a  is a cross-car view of a passenger airbag assembly with a non-inflated portion shown in the unfolded or deployed state, according to an exemplary embodiment. 
         FIG. 5   b  is a rear view of the airbag assembly of  FIG. 5   a  shown in the unfolded or deployed state, according to an exemplary embodiment. 
         FIG. 6  is a cross-car section view of the airbag assembly of  FIG. 5   a , illustrating the gas flow within the airbag assembly during deployment or unfolding, according to an exemplary embodiment. 
         FIG. 7  is a cross-car view of an exemplary embodiment of a passenger airbag assembly with a low pressure inflatable portion and a tether shown in the unfolded or deployed state. 
         FIGS. 8   a - 8   l  are cross-car views of airbag assemblies shown in the unfolded or deployed state and illustrating various shapes of the non-inflated portions, according to various exemplary embodiments. 
         FIG. 9   a  is a cross-car view of a passenger airbag assembly with a non-inflated portion, shown in the unfolded or deployed state, according to another exemplary embodiment. 
         FIG. 9   b  is a rear view of the airbag assembly of  FIG. 9   a  shown in the unfolded or deployed state, according to an exemplary embodiment. 
         FIG. 10   a  is a cross-car view of a passenger airbag assembly with a non-inflated portion, shown in the unfolded or deployed state, according to another exemplary embodiment. 
         FIG. 10   b  is a rear view of the airbag assembly of  FIG. 10   a , shown in the unfolded or deployed state, according to an exemplary embodiment. 
         FIG. 10   c  is a top view of the airbag assembly of  FIG. 10   a , shown in the unfolded or deployed state, according to an exemplary embodiment. 
         FIG. 11   a  is a cross-car view of a passenger airbag assembly with a non-inflated portion, shown in the unfolded or deployed state, according to another exemplary embodiment. 
         FIG. 11   b  is a rear view of the airbag assembly of  FIG. 11   a , shown in the unfolded or deployed state, according to an exemplary embodiment. 
         FIG. 12   a  is a cross-car view of a passenger airbag assembly with a non-inflated portion, shown in the unfolded or deployed state, according to another exemplary embodiment. 
         FIG. 12   b  is a rear view of the airbag assembly of  FIG. 12   a , shown in the unfolded or deployed state, according to an exemplary embodiment. 
         FIG. 12   c  is a top view of the airbag assembly of  FIG. 12   a , shown in the unfolded or deployed state, according to an exemplary embodiment. 
         FIG. 13  is a cross-car view of a passenger airbag assembly with multiple inflated portions, shown in the unfolded or deployed state, according to an exemplary embodiment. 
         FIG. 14  is a cross-car view of a traditional passenger airbag assembly shown in the unfolded or deployed state and illustrating the deflection of the occupant, according to an exemplary embodiment. 
         FIG. 15  is a cross-car view of a passenger airbag assembly with a non-inflated portion shown in the unfolded or deployed state and illustrating the decreased deflection of the occupant, according to an exemplary embodiment. 
         FIG. 16   a  is a cross-car view of a driver airbag assembly with a non-inflated portion, shown in the unfolded or deployed state, according to another exemplary embodiment. 
         FIG. 16   b  is a rear view of the airbag assembly of  FIG. 16   a , shown in the unfolded or deployed state, according to an exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Referring generally to the FIGURES, airbag assemblies are disclosed, which include airbags having non-inflated portions to improve restraint and reduce impact of the occupant during a vehicle dynamic impact event. Restraint of the occupant is improved by reducing the restraint forces imparted from the airbag to the occupant by reducing the deflection and acceleration the occupant undergoes during a vehicle impact event, and by having a tailored stiffness, which may be variably configured along the profile of the airbag to further reduce restraint forces imparted onto vital areas of the occupant, such as the head and neck regions. 
     Referring to  FIG. 1 , an exemplary embodiment of a motor vehicle  20  is illustrated and includes an airbag assembly  30 . The vehicle  20  is illustrated as a typical sedan, but the device of this disclosure may be used within any type of passenger vehicle as well as other moving vehicles that offer occupant protection to seated passengers in the form of frontal airbags. The airbag assembly  30  may be used within the vehicle  20  to provide any occupant (e.g., driver, passenger) of the vehicle  20  with frontal protection during a vehicle dynamic event that triggers deployment of the airbag assembly  30 . 
     Referring to  FIG. 2 , the passenger compartment  21  of the vehicle  20  of  FIG. 1  is illustrated, according to an exemplary embodiment, and includes a seat assembly  22 , a dashboard assembly  24 , and an airbag assembly  30 . The airbag assembly  30  may be coupled to the dashboard assembly  24  to accommodate varying customer packaging requirements. According to another exemplary embodiment, the airbag assembly  30  may be incorporated within or as part of the dashboard assembly  24 , such that the vehicle manufacturer will install one assembly opposed to separate assemblies. The airbag assembly  30  is flexibly configurable for use in varying package requirements, and may be tailored to satisfy specific needs of the vehicle manufacturer. 
     Referring to  FIG. 3 , the airbag assembly  30  is illustrated in the undeployed state and in its stored position. The airbag assembly  30  is shown stored within the dashboard  24 , above the glove-box  26 , and rearward of the windshield  25 . According to other embodiments, the airbag assembly  30  may be configured within or coupled to the glove-box  26 . According to an exemplary embodiment, the airbag assembly  30  includes an airbag  31 , a gas generator (or inflator)  37 , and a housing  39 . The housing  39  may be made from steel or other useful material (e.g., aluminum, magnesium, composite, polymer) and configured for attachment to the dashboard  24 , the glove-box  26 , or any other useful component of the vehicle  20 . The housing  39  may further provide structural support to the airbag assembly  30 , may store the folded airbag  31 , and may retain the gas generator  37 . 
     Referring to  FIG. 4 , the airbag  31  is illustrated in its deployed or unfolded state, providing frontal protection to the occupant  23  seated in the seat assembly  22  of the passenger compartment  21 . During a vehicle dynamic impact that triggers deployment of the airbag  31 , the gas generator  37  generates inflation gas, typically through the use of an explosive charge (e.g., pyrotechnic device). The inflation gas is then forced into the inflatable chambers of the airbag  31 , such as the first inflated chamber or inflatable portion  34 . The gas causes the airbag  31  to expand, breaching the dashboard assembly  24 , and then to deploy and unfold toward the occupant  23  seated in the seat assembly  22 . As the inflatable chambers fill with inflation gas, the airbag  31  deploys in substantially upward and rearward directions toward the occupant to protect the head and torso of the occupant  23 . Upon deployment, the airbag  31  includes the first inflated chamber or inflatable portion  34  and a non-inflatable or less inflatable portion  33 . 
     The occupant  23  displaces in the forward direction due to acceleration induced by a frontal impact of the vehicle  20 , and comes into contact with the deploying airbag  31 , which minimizes the displacement and the acceleration of the occupant  23 . By reducing the displacement and acceleration of the occupant  23 , the force and energy imparted onto the occupant  23  are reduced, reducing impact of the occupant  23 . 
     Referring to  FIGS. 5-10 , the airbag assembly  30  is shown in the deployed or unfolded state, according to an exemplary embodiment, and includes the airbag  31  and the gas generator  37 . The airbag  31  may be made from a traditional airbag material, such as high strength nylon, and may comprise of one or more than one panel coupled through a conventional method, such as stitching. When deployed, the airbag  31  includes at least one inflated chamber  34  and at least one non-inflated or less inflated portion  33 . The inflated chamber  34  may include one or more than one portion, whereby each portion may or may not be interconnected with other portions. The portions of the inflated chamber  34  may be separate from the other portions, but each portion has the same internal pressure during deployment. According to other embodiments, airbags that have multiple chambers, may have different internal pressures from chamber to chamber, but different portions within each respective chamber should have the same internal pressure. According to some exemplary embodiments, the non-inflated or less inflated portion  33  may be a void within the airbag  31  (e.g., open to the atmosphere) that is not inflated ( FIG. 6 ). In other exemplary embodiments, the non-inflated or less inflated portion  33  may be a second chamber ( FIG. 7 ) having a lower pressure than the inflated chamber  34 . 
     The airbag  31  is configured to inflate into a position where the non-inflated or less inflated portion  33  is defined or bounded by interior surfaces of the inflated chamber  34 . In one exemplary embodiment, the ratio of the volume of a space enveloped by the inflatable portion  33  to a volume of the inflatable portion  33  may be greater than or equal to approximately 1.2. In other exemplary embodiments, the ratio may be greater than about 1.0, between about 1.2 and about 1.5, about 1.3, about 1.4, or about 1.5. A conventional airbag may have an inflatable space of about 120 L of gas, however the airbag described in the various exemplary embodiments herein may have an inflatable space of less than 120 L, between about 70 L and 100 L, or about 85 L. 
     The different portions may be configured to achieve a certain gas flow during airbag deployment. For example, as shown in  FIG. 6 , the inflation gas may flow in a counter-clockwise direction from the front of the airbag  31  to the lower-rear portion of the airbag  31 , then up the center-rear portion to the upper-rear portion. Between the upper-rear portion and the upper front portion, the airbag  31  includes a point or an edge where the gas does not flow between portions of the inflated chamber  34 . For example, the point or edge may be stitched, bonded, adhered, and/or otherwise joined together to prevent gas from flowing between the upper-rear and upper-front portions. According to other embodiments, the gas flow may be configured to flow in a clockwise direction, both clockwise and counter-clockwise directions, or any useful direction. 
     The non-inflated portion  33 , according to the exemplary embodiment illustrated, may have a cross-car shape that is substantially triangular, which is positioned substantially central in the cross-car view to the deployed airbag  31 , extending rearward and upward, and may also extend in the cross-car direction the entire width of the airbag  31  as shown in  FIG. 5   b . According to other exemplary embodiments, such as those illustrated in  FIGS. 8   a - 8   l , the non-inflated portion  33  may vary in shape (e.g., round, teardrop, polygon, random), taking the form of any useful shape, may vary in size, and may vary in position on the airbag  31 . The configuration (e.g., shape, size, position) of the non-inflated portion  33  is not limited to those embodiments illustrated in  FIGS. 8   a - 8   l , rather the illustrated embodiments show that a non-inflated portion may take any shape that is advantageous to varying customer requirements. According to an exemplary embodiment, the non-inflated portion  33  may be a void within the airbag  31 , which is not inflated during airbag deployment. The void may have a tailored geometry to adjust the stiffness and the volume of the airbag  31  to tailor restraint forces exerted onto the occupant during airbag deployment. According to another embodiment, the non-inflated portion  33  may be a portion of the airbag that is constructed (e.g., stitched) to not inflate during airbag deployment, or may be a portion of another fabric that is coupled (e.g., stitched) to the airbag to form a portion of the airbag which does not inflate during airbag deployment. 
     The non-inflated portion  33  affects the stiffness of the airbag  31 , when deployed, by compressing, crumpling, or displacing when subjected to a lower force relative to the force required to compress or displace the portions of inflated chamber  34 . The shape, size, and position of the non-inflated portion  33  primarily affect the stiffness of the airbag  31  and may be tailored specifically to achieve a predetermined displacement from a predetermined force. During a vehicle dynamic impact event, the occupant  23  (or a portion, such as the head, of the occupant  23 ), having a mass, displaces with an acceleration caused by the deceleration of the vehicle. This accelerating mass creates a force and a reaction force when the mass contacts another object, such as a deploying airbag. When the occupant  23  contacts the airbag  31 , the airbag imparts restraint forces onto the occupant at the areas of contact, such as the head and torso, decelerating and protecting the occupant. The reaction forces exerted by the occupant onto the airbag displace (i.e., compress in the fore-aft direction) the airbag along the areas of contact. The displacement of the airbag and hence the force the airbag imparts onto the occupant are affected by the stiffness of the airbag  31 . The non-inflated portion  33 , having no internal pressure or a lower internal pressure relative to the inflated chamber, lowers the stiffness of the airbag  31  by having a lower stiffness relative to the stiffness of the inflated portions of the airbag. This lower stiffness allows the non-inflated portion  33  to collapse or compress when subjected to a lower force relative to the inflated chamber. Therefore the airbag  31  having a non-inflated portion  33  tailors the stiffness along the airbag profile to reduce the restraint forces imparted onto the contacting occupant, during airbag deployment, by absorbing energy generated from the vehicle impact. 
     The varying shape of the non-inflated portion  33  produces varying degrees of stiffness of the airbag  31  along the profile of the airbag which comes in contact with the occupant  23 . The thicker portions of the non-inflated portion  33  and the thinner portions of the inflated chamber  34  (in the fore-aft direction) produce a lower stiffness relative to the thinner portions of the non-inflated portion  33  and the thicker portions of the inflated chamber  34 . The substantially triangular shape and position of the non-inflated portion  33  illustrated in  FIGS. 5-10  provide variable stiffness along the profile of contact of the airbag  31 . This shape provides for a relative high stiffness for the portion below the non-inflated portion  33  that supports the chest and torso regions, while creating a relative medium stiffness for the portion above the rearward facing corner of the triangle of the non-inflated portion  33  that supports the head and neck regions, and also provides for a relative low stiffness in the portion of the rearward facing corner of the triangle that may support the head of a smaller occupant, such as a fifth percentile occupant. The relative high, medium, and low stiffness portions are illustrated in  FIG. 6 . Thus the non-inflated portion  33  of the airbag  31  is configured to provide varying stiffness to different body features of different size occupants, optimizing occupant protection. 
     The non-inflated portion  33  also affects the overall volume of the airbag  31 . The airbag  31  having the non-inflated portion  33  will have less inflated volume (when deployed) than a conventional airbag, having substantially the same outer profile, such as illustrated in  FIG. 14 , due to the reduction in volume created by the non-inflated portion  33 . This volume reduction could allow for the use of a smaller gas generator  37  for the airbag assembly  30 , reducing weight and cost, or could allow for a shorter deployment time of the airbag assembly  30 . According to another exemplary embodiment, the airbag  31  having the non-inflated portion  33  could have an increased outer profile with substantially the same inflated volume (when deployed) as an airbag assembly without a non-inflated portion. For example, an airbag could be lengthened in the fore-aft direction, bringing the deployed airbag closer to the occupant, and reducing the deflection or displacement the occupant undergoes during a vehicle crash prior to contact with the airbag, such as the airbag illustrated in  FIG. 15 . 
     The airbag  31  may further include one or more than one vent hole  36 . According to the exemplary embodiment shown in  FIG. 7 , the airbag  31  of the airbag assembly  30  includes a first inflated chamber  34 , a side panel  32 , a second inflated chamber  35  (low pressure), two vent holes  36  to atmosphere, and a flow restricting channel or vent hole  40  between the chambers  34 , 35 . The side panel  32  may be coupled to the inflated chamber  34  to form the second inflated chamber  35 . The vent holes  36  may be used, as shown, to exhaust inflation gas from the inflated chamber  34  or the second inflated chamber  35  directly to the atmosphere (i.e., outside of the airbag assembly  30 ). The vent hole  40  may be used to transfer inflation gas from the first inflated chamber  34  to the second inflated chamber  35 . According to other embodiments, a vent hole may be used to transfer or exhaust inflation gas to other areas, portions, or chambers of the airbag assembly, and those skilled in the art will recognize that vent holes are not limited to these illustrated embodiments. 
     Also referring to  FIG. 7 , the airbag assembly  30  may further include at least one tether  41 . The tether  41  may be coupled to the airbag  31  using conventional methods (e.g., stitching) to improve airbag deployment, or may be used to modify airbag stiffness by controlling the opening or closing of a vent hole  40 . The tether  41  may be coupled to the inside of the chamber of the airbag, may be coupled to the exterior of the airbag, or any useful combination or configuration. According to an exemplary embodiment, the tether  41  may be brought into tension induced by the expansion of the inflated chamber  34  being filled with inflation gas. During deployment, but prior to contact with an occupant, this tension in the tether  41  may exert a closure force which exceeds the force from the inflation gas trying to open the vent hole  40 , therefore keeping the vent hole  40  shut and prohibiting inflation gas from exhausting out through the vent hole  40 . However, upon contact between the occupant  23  and the airbag  31 , the tension in the tether  41  is reduced due to the force imparted onto a portion of the inflated chamber  34  proximate to the tether  41  by contact from the occupant being accelerated. When the opening force on the vent hole  40  (exerted by the inflation gas within the inflated chamber  34  pressurizing the chamber) exceeds the closing force on the vent hole  40  (from the tension in the tether  41 ), the vent hole  40  opens allowing inflation gas to exhaust (or vent) out of the inflated chamber  34 . The inflation gas exhausted through the vent hole  40  may vent into the second inflated chamber  35 , inflating the second inflated chamber  35 . The second inflated chamber  35  is inflated to a pressure that is lower than the pressure in the inflated chamber  34 , reducing the stiffness of the airbag  31  upon occupant impact. According to various exemplary embodiments, the size of the vent hole  40  may be increased or decreased to tailor the amount of gas flowing into the second chamber  35  and thus to tailor the stiffness of the airbag  31 . 
     According to another exemplary embodiment illustrated in  FIG. 13 , a multiple chamber airbag assembly  130  is shown and includes an airbag  131  and a gas generator  37 . Airbag  131  includes a first inflated chamber  34 , a second inflated chamber  35 , a vent hole  40 , and a tether  41 . During a vehicle dynamic event that triggers deployment of the airbag assembly  130 , the gas generator  37  generates and forces inflation gas directly into the first inflated chamber  34 , expanding and unfolding the airbag  131 . The tether  41  may be coupled to the airbag  131  so that as the airbag  131  expands and pressure within first inflated chamber  34  increases, the tension in the tether  41  will also increase, whereby the tension in the tether  41  imparts a closure force onto the valve cover of the vent hole  40 , which exceeds the force from the inside pressure of the first inflated chamber  34  trying to open the valve cover of the vent hole  40 . The airbag assembly  130  is configured so that when an occupant contacts the airbag  131  (induced by deceleration of the vehicle during impact), the force from the occupant compresses a portion of the inflated chamber  34  proximate to the tether  41 . This compressing reduces the tension in the tether  41  so that the force from the inside pressure of the first inflated chamber  34  exceeds the closure force imparted on the valve cover of the vent hole  40  by the tether  41 , thereby opening the valve cover of the vent hole  40 . According to this embodiment, when the valve cover of the vent hole  40  is open, inflation gas exhausts from the first inflated chamber  34  through vent hole  40  into the second inflated chamber  35 . This venting may reduce occupant impact by tailoring the stiffness of the airbag to reduce the energy imparted into the occupant from contact with the airbag by directing some energy to diffuse gas from the first inflated chamber  34  into the second inflated chamber  35 . 
     The multiple chamber airbag assemblies, as disclosed, in addition to improving occupant restraint also retain the advantage of having a possible volume reduction, since the inflation gas used to inflate the second inflated chamber  35  is reused, or first used to inflate the first inflated chamber  34 . By reducing the airbag volume that the gas generator  37  directly inflates, the use of a smaller and less expensive gas generator may be permissible. According to other embodiments, the same gas generator may be used, but the inclusion of a non-inflated volume within the airbag assembly allows for the size of the airbag to increase in the direction toward the occupant and still have substantially the same inflated volume as an airbag configured without a non-inflated portion. The airbag having the non-inflated portion may improve occupant protection by minimizing deflection and acceleration of the occupant, by providing a contact position between occupant and airbag which is closer to the position of the occupant prior to the vehicle dynamic impact event. 
     According to the exemplary embodiment shown in  FIG. 13 , the airbag assembly  130  may further include a non-inflated or less inflated portion  35 . According to other embodiments, a multiple chamber airbag assembly may include the non-inflated or less inflated portion  35  within the first inflated chamber, between any two or more chambers, or configured in any useful manner. The multiple chamber airbag assembly  130  may also include more than one vent hole  40 , for example to vent from the first inflated chamber  34  to the non-inflated or low pressure portion  35 . One or more other vent holes  36  may be used to exhaust gas from any chamber to outside of the airbag assembly  130 . By venting inflation gas through multiple chambers prior to exhausting the gas to the atmosphere (i.e., or outside the airbag assembly), the temperature of the gas is lowered, reducing the chance of damage (e.g., burn damage) to the vehicle or occupants from the gas. The multiple chamber airbag assembly  130  may also include more than one tether  41 . 
     The airbag assembly  30 ,  130  may further include a side panel  32 , which may be made from a traditional airbag material, such as high strength nylon. The side panel  32  may comprise one or more panels coupled through a conventional method, such as stitching. According to an exemplary embodiment, the side panel  32  may be coupled using conventional methods (e.g., stitching) to the first inflated chamber  34  of the airbag  31 , 131  to form the second inflated chamber  35 , such as shown in  FIG. 13 . According to other embodiments, the side panel  32  may be coupled to any feature or member of the airbag  31 , 131 , or any combination of features or members of the airbag  31 , 131 , to form at least one chamber that is indirectly inflated from inflatable chamber  34  through at least one vent hole  40 . The side panel  32  may further include a vent  36  for venting exhaust gases from the second inflated chamber  35  to the atmosphere. The vent  36  may be positioned on one or both sides of the second inflated chamber  35 . The side panel  32  may be configured to form a non-inflated portion  35  when coupled to the airbag  31 , 131  or coupled to a second side panel. 
     Referring to  FIGS. 9   a  and  9   b , an airbag assembly  330  is illustrated in its deployed or unfolded state, and includes a gas generator  37  and an airbag  331 . The airbag  331  includes an inflated chamber  34  and a non-inflated portion  33 . The non-inflated portion  33  comprises a cross-car portion and a fore-aft portion. The cross-car portion of the non-inflated portion  33 , as shown, may be substantially ear-shaped and may run the entire width of the airbag  331 . The non-inflated portion  33  may have varying shapes and varying widths and may be configured in varying positions along the airbag  331 . The fore-aft portion of the non-inflated portion  33 , as shown, may be substantially oval-shaped and may extend from the rear-most surface (i.e., the leading edge during deployment) of the airbag  331  to the cross-car portion of the non-inflated portion  33 . According to other embodiments, the fore-aft portion may have varying shapes, may extend having varying depths, and may have varying positions. According to an exemplary embodiment, the fore-aft portion of the non-inflated portion  33  is positioned to retain the head of the occupant during a dynamic impact in a manner that does not generate a moment about the base of the neck of the occupant (in a clockwise or counterclockwise rotation in a cross-car view, such as  FIG. 9   a ) that could induce whiplash of the occupant. The fore-aft portion of the non-inflated portion  33  may be configured to reduce forces into the head and neck of the occupant, during airbag deployment, but maintain the required high stiffness of the airbag  331  in the regions supporting the shoulders of the occupant. 
     Referring to  FIGS. 10   a - 10   c , an airbag assembly  430  is illustrated in its deployed or unfolded state, and includes a gas generator  37  and an airbag  431 . The airbag  431  may be made from one or more than one panel coupled together, and includes an inflated chamber  34 , a non-inflated portion  33 , and at least one pocket  38  (or split). The pocket  38  may form an exterior void along the airbag  431 , for example a V-shaped void with the base of the V pointing toward the inside of the airbag. A pocket, such as pockets  38 ,  38 ′ may reduce the inflated volume of the airbag  431  or may lessen impact with the occupant. According to an exemplary embodiment, pocket  38  may be formed in the center (cross-car) of the rear facing surface (i.e., leading edge during deployment) of the airbag  431  and may have a non-inflated portion  33  positioned forward of the pocket  38 . When the airbag  431  is deployed, the pocket  38  is configured to lower the restraint forces imparted into the head and chest of the occupant, by allowing the shoulders of the occupant to absorb more impact loads. The airbag assembly  430 , having a non-inflated portion  33  positioned forward of the pocket  38 , may further reduce impact with the occupant by having a tailored stiffness through the region of contact with the head, neck and upper chest of the occupant. The tailored stiffness may result in relative lower restraint forces imparted from airbag  431  to the head and neck of the occupant. The pockets  38 ,  38 ′ may be configured to reduce impact for out of position occupants as well. 
     Referring to  FIGS. 11   a  and  11   b , an airbag assembly  530  is illustrated in its deployed or unfolded state, and includes a gas generator  37  and an airbag  531 . The airbag  531  includes an inflated chamber  34  and a non-inflated portion  33 . According to an exemplary embodiment, the inflated chamber  34 , when deployed, may have a rearward facing lower portion  46  which has a substantially trapezoidal shape. The trapezoidal shape may have a V-shaped notch when viewed from the rearward direction (i.e., by the occupant). The trapezoidal shape may also have a rearward facing upper portion  45  that necks down from a width that may be substantially the same as the width of the lower portion  46 . The shape of the upper portion  45  may substantially correspond and mate to the V-shaped notch in the lower portion  46 . The upper and lower portions  45 ,  46  may have a tongue-and-groove style interface. The V-shaped configuration of the upper portion  45  of the airbag  531  allows for a varying stiffness of airbag  531 , which results in lower restraint forces imparted into the head and neck regions of the occupant during impact. The V-shaped configuration of the lower portion  46  of airbag  531  also allows a varying stiffness of the airbag  531 . The varying stiffness may result in a relatively higher stiffness to the portions that support the shoulders of the occupant, imparting relatively higher restraint forces into the shoulders. Therefore, the V-shape configuration may reduce loading into the head, neck, and central chest region of the occupant and allow for the relative higher loading to take place through the shoulders, less vital areas of the occupant. Additionally, the V-shaped configuration of the upper and lower portions  45 ,  46  may offer improved restraint for different sized occupants, because taller occupants generally have broader shoulders and shorter occupants generally have narrower shoulders. Therefore, the V-shape configuration of the airbag supports different sized occupants. 
     According to other embodiments, the shapes and sizes of the upper and lower portions of the airbag may vary, or the airbag assemblies may also include pockets, or tethers. Additionally, the shape, size, and position of the non-inflated portion  33  may be modified to tailor the stiffness of the airbag to accommodate varying customer requirements. 
     Referring to  FIGS. 12   a - 12   c , an airbag assembly  630  is illustrated in its deployed or unfolded state, and includes a gas generator  37  and an airbag  631 . The airbag  631  includes an inflated chamber  34  and a non-inflated portion  33 . The non-inflated portion  33 , according to an exemplary embodiment, may extend in a substantially vertical direction from the top of the airbag  631  to an approximate midpoint of the depth of the airbag  631 . The non-inflated portion  33  may have a cross-section (when viewed from the top) that is substantially triangular when the airbag  631  is deployed. According to other embodiments, the non-inflated portion  33  may extend from other surfaces, such as from the bottom surface, and may extend all the way through the depth, width, or thickness of the airbag, or may extend less than the full depth, width, or thickness of the airbag. Additionally, the cross-section may be varied to tailor the stiffness of airbag  631 . 
     Referring to  FIG. 15 , the airbag assembly  30  is shown in the deployed or unfolded state with the airbag  31  supporting the occupant  23  at the time of contact, and illustrates an advantage of the airbag assembly  30  over a conventional passenger airbag  61 , shown in  FIG. 14 . The airbag  31  may have substantially the same inflated volume as the conventional airbag  61 , but because the airbag  31  has a non-inflated portion  33 , the airbag  31  is longer in the fore-aft direction. Having the same inflated volume allows for each airbag assembly to be constructed using the same gas generator  37 , however, because the airbag  31  is longer in the fore-aft direction, the airbag  31  allows for a lower displacement “d” and angle of rotation “a” of the occupant  23  (as illustrated in  FIG. 15 ) compared to the displacement “D” and angle of rotation “A” of the occupant  23  (as illustrated in  FIG. 14 ) for the conventional airbag  61 . The displacement “d” and “D” correspond to the fore-aft distance the occupant travels from the initial pre-vehicle impact position to the occupant-airbag impact position. Therefore, by allowing less displacement of the occupant relative to conventional airbags, the airbag  31  having a non-inflated portion  33  reduces impact of the occupant by restraining the occupant when the occupant has a lower energy and inertia. The more displacement (“D” or “d”) the occupant is allowed to undergo during a vehicle dynamic impact event, the higher the acceleration of the occupant is upon impact with the airbag, resulting in higher restraint forces imparted from the airbag onto the occupant. 
     Referring to  FIGS. 16   a  and  16   b , a driver airbag assembly  180  is illustrated in its deployed or unfolded state, and includes an airbag  181 . The airbag  181  may be coupled directly to the steering assembly  96  of a vehicle, such as the vehicle  20 . The airbag  181  may include a gas generator, which generates and forces inflation gas directly into the airbag  181  when triggered by a dynamic impact event. During deployment, the airbag  181  includes an inflated chamber  184  and a non-inflated portion  183 . According to an exemplary embodiment, the inflated chamber  184  includes a round base portion  185  (when viewed by the driver) that has a substantially uniform thickness. The inflated chamber  184  may also include a support portion  186  that is interconnected to the base  185  at the bottom and the top side. As shown, the support portion  186  and the base portion  185  may be separated by a gap having a varying depth between the interconnections on the top and bottom sides. The support portion  186 , according to the exemplary embodiment shown, may be wider at the top and bottom sides relative to the center portion, such that the side surfaces are concave. According to other embodiments, the support portion  186  may have any useful profile when viewed the rear. The support portion  186  includes a pocket  188 , which according to an exemplary embodiment, is oval shaped when viewed from the rear and extends through the entire fore-aft depth of the support portion  186 . The pocket  188  may be configured to form any useful shape and may extend the entire depth or any distance less than the entire depth of the support portion  186 . The pocket  188  is configured to accept a portion of the head or facial region of the occupant to reduce the restraint forces imparted into the head and neck regions to reduce occupant impact. 
     The non-inflated portion  183  forms the void that separates the base portion  185  and the support portion  186  of the inflated chamber  184  of the airbag  181 , in the fore-aft direction. According to an exemplary embodiment, the non-inflated portion  183  forms substantially a D-shape when viewed from the cross-car direction. The non-inflated portion  183  may take the form of any useful shape, and is configured to provide variable stiffness of the airbag  181  to reduce occupant impact with the airbag  181 . The stiffness of the driver airbag  181  may be tailored like the passenger airbags disclosed in this application, through variable configuration of the shape, size, and position of the non-inflated portion  183 . 
     According to other exemplary embodiments, the airbag assembly  30  may include an airbag or portions of an airbag as disclosed in U.S. Patent Application Publication No. 2005/0206138, which is herein incorporated by reference in its entirety. According to other exemplary embodiments, 
     Airbag assemblies having a non-inflated portion improve restraint and reduce impact through reducing the restraint forces imparted onto the occupant by reducing the deflection and acceleration the occupant undergoes during an impact, and by having a tailored stiffness, which may be variably configured along its profile to further reduce restraint forces imparted to vital areas of the occupant, such as the head and neck regions. Additionally, airbags having non-inflated regions may be coupled with new pre-crash technology to further improve restraint. For example, a vehicle may include new pre-crash technology, which may through sensors measure the velocity, displacement, and acceleration of the vehicle relative to other objects, and may inform the vehicle of a crash before actual impact of the vehicle. Currently, airbags are deployed using sensors that detect impact of the vehicle, so technology that predicts impact could be used to deploy the airbags sooner. This technology coupled with airbags having non-inflated portions, could further mitigate the restraint forces exerted onto an occupant during a vehicle dynamic impact event by minimizing the deflection an occupant travels during a crash event. 
     As utilized herein, the terms “approximately,” “about,” “substantially”, and similar terms are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. It should be understood by those of skill in the art who review this disclosure that these terms are intended to allow a description of certain features described and claimed without restricting the scope of these features to the precise numerical ranges provided. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and claimed are considered to be within the scope of the invention as recited in the appended claims. 
     It should be noted that the term “exemplary” as used herein to describe various embodiments is intended to indicate that such embodiments are possible examples, representations, and/or illustrations of possible embodiments (and such term is not intended to connote that such embodiments are necessarily extraordinary or superlative examples). 
     The terms “coupled,” “connected,” and the like as used herein mean the joining of two members directly or indirectly to one another. Such joining may be stationary (e.g., permanent) or moveable (e.g., removable or releasable). Such joining may be achieved with the two members or the two members and any additional intermediate members being integrally formed as a single unitary body with one another or with the two members or the two members and any additional intermediate members being attached to one another. 
     References herein to the positions of elements (e.g., “top,” “bottom,” “above,” “below,” etc.) are merely used to describe the orientation of various elements in the FIGURES. It should be noted that the orientation of various elements may differ according to other exemplary embodiments, and that such variations are intended to be encompassed by the present disclosure. 
     It is important to note that the construction and arrangement of the multiple chamber air bag system as shown in the various exemplary embodiments is illustrative only. Although only a few embodiments have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter described herein. For example, elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes and omissions may also be made in the design, operating conditions and arrangement of the various exemplary embodiments without departing from the scope of the present invention.