International Journal of Energetic Materials and Chemical Propulsion

CLEAN LIQUID AND HYBRID GAS GENERATOR SYSTEM FOR INFLATING CAR AIRBAGS

Краткое описание

The need to clean and low cost gas generator systems for the use to inflate the airbags in motor vehicles has greatly increased. Aiming to avoid the disadvantages of solid azide- and tetrazol-based gas generants, and combinations of high pressure inert gas with solid propellants to be adapted in current and near-future airbags, this investigation has been carried out to manage to apply water solutions of stabilized hydrogen peroxide from 55 to 60wt% in concentration to the combustors to be integrated in airbag module. There are some favorable properties with such a low concentration H₂O₂ solution: azeotropic behavior to suppress the freezing point lower than 233K, no hazard of causing the spontaneous explosion accident due to the self-accelerated decomposition during long time storage in confined vessel, low production cost and contribution to downsizing of the modules. First of all, however, it must be stressed that the decomposition products of H₂O₂ emitted from airbags into the environment are only clean oxygen, water haze and dry vapor.
This paper reports the achievement of successfully combusting simple H₂O₂ solution and hybrid propellant consisting of H₂O₂ solution of achievement in the practical application of the combustors loading simple H₂O₂ solution combined with pressurized oxygen to inflate airbags for passenger cars. In order to acquire the design data a series of investigation was conducted by means of heavy wall combustors to develop the starter for realizing the H₂O₂ decomposition at the designated time sequence, and developed a two stage injection method which pours the incandescent combustion products into H₂O₂ solution. At the event of collision the initiator should start, followed by firing the main booster. The initiator is the B/KNO₃ pyrotechnic granules and pellets, catalyst powder and the booster is the pyrotechnics powder and highly energetic material. The total amount is approximately 3∼7g. The combustor is divided to a primary reaction chamber in which gas generant cartridge is placed and a secondary decomposition chamber putting the catalyst net for completing H₂O₂ decomposition. The experimental gas generator systems have proved to be capable of meeting the strict safety and environment standards and of corresponding to the time budget, which are requested in the deployment procedure items for 60 and 150 liter airbags at the temperature from 233 to 363K specified by Japanese Industrial Standards.