This paper presents and discusses the development of a new air bag inflator based on fast combustion reactions of methane-oxygen mixtures. The performance of this inflator was evaluated in terms of pressure-time relationships inside the inflator and in a receiving tank simulating an air bag, and by assessing the temperature-time relationship in the tank. Several critical issues were studied, including stoichiometry, initial mixture pressure, and extreme ambient conditions, in order to develop the inflator. Other design parameters were investigated and optimized: burst disk thickness and type, ignition device, tank purging gas, concentration of carbon monoxide (CO), severity of temperature in the tank, and the inflator size. A theoretical and integrated model was developed in order to simulate the behaviour of the inflator. The experimental results made at different conditions were found to be in agreement with the model. The performance of the inflator was compared with that of sodium azide, and strategies for its implementation in an actual air bag system were formulated.
Abstract