Method for inflating a gas bag and gas bag module for use in this method

Inactive Publication Date: 2005-09-01
TRW AIRBAG SYST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0010] The use of ammonium perchlorate as prevailing or even sole oxidizing agent makes possible the provision of gas-generating mixtures which are practically totally converted into gas during combustion. Hereby, a maximum efficiency of the propellant is achieved. Ammonium perchlorate is, furthermore, compatible with almost all organic fuels. The gas generators, owing to the use of pyrotechnic propellants with a high gas yield of over 95 percent, can be operated with a smaller quantity of propellant than conventional gas generators. Gas yield is to be understood here as the mass of the generated gas in relation to the mass of the propellant which is used. The gas generators can therefore be produced so as to be smaller and, by dispensing with cumbersome and expensive filter materials, also lighter and more favourably priced. The hydrochloric acid occurring from the reaction of the ammonium perchlorate with the fuel is reliably neutralized inside the gas bag. Therefore, no toxic or corrosive gas arrives into the interior of the vehicle. Furthermore, through the evolution of heat of the neutralization reaction, the service life of the gas bag is also increased.

Problems solved by technology

Owing to the high toxicity of these mixtures, recently, however, propellants based on organic fuels and inorganic oxidizing agents are being used.
Therefore, large quantities of so-called slag-forming constituents or cooling agents must be added to these azide-free propellants, which, however, reduce the gas yield of the propellant.
With the burning of propellants containing ammonium perchlorate, however, hydrochloric acid is produced as a by-product, which is not desirable, owing to its toxicity and corrosivity.
These mixtures, however, likewise have an insufficient gas yield, owing to the additives which are then necessary.
The described arrangement of an additional container in the gas bag leads, moreover, to increased structural space requirements.
Also, a complete distribution of the substances arranged in the container during the short unfolding phase of the gas bag is not guaranteed.
The coating therefore promotes only the adjustment of the balance of the components present in the gas mixture which, however, will be dependent on further external parameters such as pressure and temperature and will only occur to a very incomplete extent owing to the short reaction time which is available.

Method used

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Embodiment Construction

[0011] In accordance with the invention, the coating has a constituent of chemical substances which react directly with the hydrochloric acid and convert the latter into harmless solid reaction products. Thereby, the gaseous hydrochloric acid occurring in the combustion reaction is reliably held back in the gas bag. The chemical substances can be selected for example from the group consisting of the oxides, peroxides, hydroxides, carbonates, hydrogen carbonates and oxalates of alkali metals, alkaline earth metals and transition metals and also mixtures thereof. These substances are easily available and favourably priced. Furthermore, for example, organic amines or polymeric compounds with basic functional groups are also able to be used. Polymeric compounds of the group of polyamines and ion exchanger resins are suitable to a particularly preferable extent. All these compounds are also able to be used in a mixture with each other.

[0012] Moreover, surface-active substances can also ...

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Abstract

A method for inflating a gas bag of a safety arrangement in vehicles provides a gas generator which contains a pyrotechnic propellant comprising an organic fuel and ammonium perchlorate as an oxidizing agent. The pyrotechnic propellant, after its activation, releases a gas which has an amount of hydrochloric acid. A coating is arranged on the inner surface of the gas bag, on which the hydrochloric acid is neutralized or absorbed.

Description

TECHNICAL FIELD [0001] The invention relates to a method for inflating a gas bag of a safety arrangement in vehicles and also a gas bag module for use in this method. BACKGROUND OF THE INVENTION [0002] Safety arrangements for vehicles usually contain a gas bag module which comprises an inflatable gas bag and a gas generator connected to the gas bag. The gas generator usually contains a pyrotechnic propellant which is activated as a result of a vehicle accident and within a very short space of time releases a gas or gas mixture for inflating the gas bag. [0003] In the past, in particular mixtures of sodium azide and inorganic nitrates were used as pyrotechnic propellant. Owing to the high toxicity of these mixtures, recently, however, propellants based on organic fuels and inorganic oxidizing agents are being used. These azide-free propellants are distinguished by high combustion temperatures which favour the occurrence of liquid or gaseous by-products. Therefore, large quantities of...

Claims

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Application Information

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IPC IPC(8): B60R21/16B60R21/235C06B23/02C06B29/22C06D5/06
CPCB60R21/235B60R2021/23514C06D5/06C06B29/22C06B23/02
InventorZEUNER, SIEGFRIEDREIMANN, UWESCHROPP, ROLANDROEDIG, KARL-HEINZ
OwnerTRW AIRBAG SYST