Browse Prior Art Database

Passive Adaptive Can Vent for Airbags

IP.com Disclosure Number: IPCOM000147698D
Publication Date: 2007-Mar-21
Document File: 7 page(s) / 79K

Publishing Venue

The IP.com Prior Art Database

Abstract

Concept describes vent that can be added to either the bag or container of an airbag to replace, or supplement the normal venting. The vent is designed so that vent area is regulated by the gas pressure inside the airbag. It may have a low effective area (~20%) for the high pressure condition when the inflator is deployed before the airbag door is opened to provide 'can venting' to improve out of position performance. The effective vent area also adapts during normal use to provide optimum venting for both belted and unbelted occupants in medium to high severity crash events.

This text was extracted from a Microsoft Word document.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 23% of the total text.

ABSTRACT     Passive Adaptive Can Vent for Airbags

Concept describes vent that can be added to either the bag or container of an airbag to replace, or supplement the normal venting.

The vent is designed so that vent area is regulated by the gas pressure inside the airbag.

It may have a low effective area (~20%) for the high pressure condition when the inflator is deployed before the airbag door is opened to provide "can venting" to improve out of position performance. The effective vent area also adapts during normal use to provide optimum venting for both belted and unbelted occupants in medium to high severity crash events.

The vent area may be regulated by a pressure sensitive plate / diaphragm acting on a valve with the appropriate flow characteristics.  

Vent offers following advantages

1.     Vent area self regulates according to internal bag pressure to provide optimized vent characteristic.  (This is also possible in the industry using pyrotechnically activated vents but at higher cost and only in discrete steps and dependant on a separate control system) 

2.     The efficiency of the bag will be improved over conventional bags as less gas is vented prior to occupant contact with the bag

3.     Possible to provide "aspiration" to help fill the bag

4.     The vent will also tend to compensate for the inflator output dependency on temperature

5.     Allowing all the venting through the can also avoids / reduces inflator effluent entering the passenger compartment.  This may permit simplifications in inflator design, e.g. reduced filter area giving higher gas yield, giving lower overall system cost

6.     The adaptivity of the vent may help compensate variability of inflator with respect to temperature

7.     Improved out of position performance.  Ability to locate full venting in the can allows earlier gas exit, i.e. if door opens slowly due to occupant loading,  a proportion of venting is available immediately without delay required for unfolding bag to expose conventional bag located vent

 

                                                                                                           

1st February 2006

Subject:  Passive Adaptive Can Vent for Airbags

Conventional Airbag Can Venting

A proportion of the venting may be through the rear of the airbag housing, where the area is tuned to

1. be small enough so that not too much gas volume from the inflator is lost before the airbag door is opened.  Limiting case is at cold temperature with lowest inflator gas output and strongest door opening resistance, where if vent is too large door may not open, or open late with insufficient gas in the bag for occupant restraint

2. be large enough to allow the gas to be "dumped" in the case where an occupant may be in...