Effect of Gas Thermodynamics on the Aggressiveness of Airbag Inflator

In automotive industry, aggressiveness of airbags is associated with the output of inflators, which is often presented by tank pressure. The purpose of this paper is to give an in-depth discussion of the thermodynamics behind the airbag inflator so that we can understand correctly and utilize properly the relationship between inflator power and tank pressure. In this paper, through a more rigorous derivation and a detailed analysis of the tank tests, we not only qualitatively analyze the relationship of inflator power to tank pressure, the heat transfer effect and the gas composition effect, but also we quantify the contribution of these parameters. The numerical algorithm and calculations also have been shown here for the most common types of the inflators, such as azide and non-azide pyrotechnic inflators, stored gas inflators and hybrid inflators to verify the analytic predictions and conclusions.