Patent Application
20150054265
The present invention generally relates to a side air curtain for a motor vehicle to optimize side impact protection while simultaneously providing occupant ejection mitigation from the vehicle during a vehicle side impact or rollover event, specifically a side air curtain that includes a controlled pressure chamber that provides a variable pressure chamber throughout the course of the impact event.
Side air curtain systems for use in motor vehicles have been adopted to mitigate occupant ejection during motor vehicle side impact or rollover events, and are generally well-known in the art. Traditionally, such side air curtain systems have been used in combination with exterior motor vehicle components to manage and control motor vehicle impact events with external objects and rollover events. In particular, Federal Motor Vehicle Safety Standard (FMVSS) No. 226 has been promulgated to address side impact and rollover events that potentially may result in occupant ejection from the interior of the motor vehicle. In sum, where a side air curtain is employed to mitigate occupant ejection, FMVSS 226 presently requires the side air curtain to maintain pressure for up to 6 seconds after deployment.
Further, side impact airbag systems have been developed to address vehicle intrusion in the event of a side impact pursuant to FMVSS 214 and to provide occupant restraint against occupant collision with interior motor vehicle components, such as the so-called A pillar, B pillar, and interior upper rail assembly. In contrast to side air curtains, however, side airbag systems are designed to deploy very rapidly after detecting the first impact event and stay inflated for only about 100 milliseconds.
Since side air curtain pressure must be sustained over the 6 seconds duration of inflation, the side air curtain initial pressure is typically raised to a level sufficient to provide stiffness in the side air curtain throughout the 6 seconds set forth in the requirements of FMVSS 226. However, higher initial side air curtain pressures have been found to aggravate head impact response criteria upon initial impact. Thus, to comply with both FMVSS 214 and FMVSS 226, a lower initial pressure in the side air curtain is desirable, with a higher sustained pressure provided later in the impact event.
To achieve such a goal, a dual stage inflator can be used. A first stage inflator can be used to pressurize the side air curtain to a first pressure for a limited time after the first impact, with a second stage inflator used to pressurize the side air curtain to a second, higher pressure later in the impact event to mitigate ejection. However, such a dual stage inflator system presents a cost penalty, presents significant packaging challenges, and adds weight to the motor vehicle. Hence, solutions for providing side impact occupant protection while also mitigating occupant ejection during such side impact events would be advantageous.
The vehicle side air curtain disclosed herein particularly accomplishes the foregoing optimization of vehicle performance and provides a cost-efficient approach to address the problem by employing a side air curtain having an integral separate, self-contained controlled pressure chamber in the location required for compliance with FMVSS 214 in limited fluid communication with the remainder of the side air curtain. For a limited period of time, the controlled pressure chamber of the side air curtain experiences an initial pressure favorable to head impact protection during the initial impact time period, while the remainder of the side air curtain experiences a significantly higher initial pressure adapted to optimize the longer duration of the side air curtain pressurization. After the initial impact time period, the pressure differential between the controlled pressure chamber and the remainder of the side air curtain causes the pressure in each of the controlled pressure chamber and the remainder of the side air curtain to equalize at a stabilized pressure that is optimized to sustain a sufficient inflation pressure for the time required for ejection mitigation protection.
According to one aspect of the present disclosure, a vehicle side air curtain for a motor vehicle has an inflator, a main inflatable chamber, and an integral separate, self-contained controlled pressure chamber in limited fluid communication with the main inflatable chamber of the side air curtain and disposed for impact by the head and upper thoracic region of a vehicle occupant. The main inflatable chamber of the side air curtain is inflated to an initial pressure substantially immediately following actuation of the inflator and a second lower stabilized pressure thereafter to extend the duration of the pressurization of the main inflatable chamber of the side air curtain beyond the initial impact time period. The controlled pressure chamber of the side air curtain is inflated to an initial pressure substantially lower than the initial pressure of the main inflatable chamber of the side air curtain and to a pressure favorable to side impact occupant protection substantially immediately following actuation of the inflator.
Still another aspect of the present disclosure is a side air curtain where the pressure differential between the main inflatable chamber of the side air curtain and the controlled pressure chamber causes the pressure in the controlled pressure chamber to equalize with the second stabilized pressure in the main inflatable chamber after the initial impact time period, such that the pressure of each of the controlled pressure chamber and the main inflatable chamber of the side air curtain remain at relatively elevated levels thereafter to mitigate occupant ejection.
Yet another aspect of the present disclosure is a side air curtain where the initial pressure in the main inflatable chamber is at least 100 KPa within 30 milliseconds after actuation of the inflator and the second lower stabilized pressure in the main inflatable chamber is about 80 KPa within 100 milliseconds after actuation of the inflator.
An additional aspect of the present disclosure is a side air curtain where the initial pressure of the controlled pressure chamber of the side air curtain is less than 20 KPa within 30 milliseconds after actuation of the inflator and the pressure of the controlled pressure chamber of the side air curtain is about 80 KPa within 100 milliseconds after actuation of the inflator.
Another aspect of the present disclosure is a side air curtain where the pressure in each of the main inflatable chamber and the controlled pressure chamber is about 80 KPa at 100 milliseconds, which maintains sufficient pressure level in both for at least 6 seconds for ejection mitigation.
An additional aspect of the present disclosure is a side air curtain mounted on the upper side rail assembly of the motor vehicle.
A further aspect of the present disclosure is a side air curtain where the main inflatable chamber is in fluid communication with the controlled chamber via a gas vent that regulates the rate of fluid flow between the main inflatable chamber and the controlled pressure chamber.
Yet a further aspect of the present disclosure is a side air curtain where the main inflatable chamber is in fluid communication with the controlled pressure chamber via a plurality of gas vents.
An additional aspect of the present disclosure is a side air curtain where the main inflatable chamber comprises a plurality of interconnected cavities in fluid communication one to the other about their peripheries to form a substantially flat side panel to prevent occupant ejection and the controlled pressure chamber is disposed within the plurality of the cavities.
Yet another aspect of the present disclosure is a side air curtain where the controlled pressure chamber is disposed proximate the head and upper thoracic region of a vehicle occupant when deployed.
A still further aspect of the present disclosure is a side air curtain where the main inflatable chamber comprises a non-inflated vent panel that is interconnected about its periphery to the plurality of cavities.
Another aspect of the present disclosure is a side air curtain where the main inflatable chamber comprises a non-inflated vent panel disposed longitudinally proximate the middle of the flat panel and the controlled pressure chamber is disposed longitudinally forward on the flat panel and proximate the head and upper thoracic region of a vehicle occupant when deployed.
A yet additional aspect of the present disclosure is a side air curtain comprising an inflator, a main chamber, and an impact chamber in limited fluid communication with the main chamber, wherein the main chamber is inflated to a first pressure immediately after actuation of the inflator and a second pressure thereafter, and the impact chamber is inflated to a pressure substantially lower than the first pressure of the main chamber immediately after actuation of the inflator.
A further aspect of the present disclosure is a method of mitigating occupant ejection and occupant injury, the method comprising the steps of providing a vehicle side air curtain having an inflator, a main inflatable chamber, and an integral separate controlled, self-contained pressure chamber in limited fluid communication with the main inflatable chamber of the side air curtain and disposed for impact by the head and upper thoracic region of a vehicle occupant, inflating the main inflatable chamber of the side air curtain in response to a side impact or rollover event to an initial pressure substantially immediately following actuation of the inflator and a second lower stabilized pressure thereafter to extend the duration of the pressurization of the main inflatable chamber of the side air curtain beyond the initial impact time period, inflating the controlled pressure chamber of the side air curtain to an initial pressure favorable to side impact occupant protection and substantially lower than the initial pressure of the main inflatable chamber of the side air curtain substantially immediately following actuation of the inflator, and equalizing the pressure differential between the main inflatable chamber of the side air curtain and the controlled pressure chamber after the initial impact time period to the second lower stabilized pressure, such that the pressure of each of the controlled pressure chamber and the main inflatable chamber of the side air curtain remain at elevated levels to mitigate occupant ejection.
Still another aspect of the present disclosure is a method of mitigating occupant ejection and occupant injury where the initial pressure in the main inflatable chamber is at least 100 KPa within 30 milliseconds after actuation of the inflator and the second stabilized pressure in each of the main inflatable chamber and the controlled pressure chamber is about 80 KPa within 100 milliseconds after actuation of the inflator.
Yet another aspect of the present disclosure is a method of mitigating occupant ejection and occupant injury where the initial pressure of the controlled pressure chamber of the side air curtain is less than 20 KPa within 30 milliseconds after actuation of the inflator and the second stabilized pressure in each of main inflatable chamber and the controlled pressure chamber is about 80 KPa within 100 milliseconds after actuation of the inflator.
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.
In the drawings:
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
Referring to
As shown, the side air curtain 36 when deployed extends forward to the windshield 22 and rearward to the hatchback 28 and sufficiently downwardly so as to essentially obscure the front and rear side window assemblies (not shown). The side air curtain 36 is thus able to mitigate occupant ejection during a side impact event. As noted above, FMVSS 226 requires that the side air curtain 36, if employed, maintains a sufficient pressure to mitigate ejection for a period of 6 seconds after impact and deployment.
A standard side air curtain 36, without the improvement disclosed herein, is shown in
As can be seen in
Further, when a side impact or rollover event occurs, the occupant tends to move toward the vehicle side structure by inertia. However, instead of impacting the A pillar, B pillar, or upper rail of the roof assembly, the occupant's head and upper thoracic region preferably impacts a side impact airbag that is designed to optimize impacts from the head and/or thoracic regions of the vehicle occupant by being inflated to a relatively soft structure. The de-acceleration experienced by the occupant's head is thus reduced. Preferably, the region impacted by an occupant's head and upper thoracic region is less than 20 KPa at about 30 milliseconds after inflation initiation.
As noted above, however, the relative stiffness of the standard side air curtain 36 renders optimization of a relatively soft impact surface desired for alleviation of side impacts under FMVSS 214 difficult. That is, the pressure within the standard side air curtain 36 at a time period 30 milliseconds after inflation initiation, when contact of the head and thoracic region of the occupant typically occurs, is typically about 60 KPa, even though it is desirable that the region near the vehicle occupant's head and thoracic region of the side air curtain be at a pressure of less than 20 KPa at 30 milliseconds after actuation of the inflator.
The side air curtain incorporating the improvement disclosed herein is shown in
As shown in
The rate of inflation of the controlled pressure chamber 50 from main chamber 48 can be controlled through the size, number, and disposition of the gas vent 52 provided between the two chambers in the transition panel 54. That is, where a larger gas vent 52 is provided or where a plurality of gas vents 52 are provided to create a relatively large combined cross-sectional area, a higher initial pressure within the controlled pressure chamber 50, with relatively lower peak gas pressure in the main inflation chamber 48, will be experienced, as depicted in
Further, the time for pressure equalization can be regulated. For example, as noted above, in a first embodiment of the vent, as shown in
Thus, it can be readily contemplated that the performance of the controlled pressure chamber 50 to provide side impact protection under FMVSS 214 can be adjusted to provide optimal performance by controlling the size and number of the vents 52 in the transition panel 54 provided between the main inflation chamber 48 and the controlled pressure chamber 50 of the side air curtain 36. Preferably, the vent 52 provides for the main inflation chamber 48 to experience a pressure of at least 110 KPa within 30 milliseconds after actuation of the inflator 38 and approximately 80 KPa within 100 milliseconds after actuation of the inflator 38. Similarly, the air pressure in the controlled pressure chamber 50 is preferably less than 20 KPa within 30 milliseconds after actuation of the inflator 38, and more preferably less than 5 KPa, but approximately 80 KPa within 100 milliseconds after actuation of the inflator 38.
In accordance with the foregoing disclosure, the need for a second inflator to provide a higher inflation pressure to the main inflation chamber 48 of the side air curtain 36 can be avoided, while simultaneously providing the necessary relative softness to the controlled pressure chamber 50 as the side impact portion of the side air curtain 36 so as to optimize the side impact crash criteria.
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.
