Design of the Airbag Inflation System Applicable to Conventional and Autonomous Vehicles

Abstract

The emergency transformation of various aspects of life and business these days requires prompt evaluation of autonomous vehicles. One of the primary reassessments deals with the applicability of the vehicle passive safety system to the protection of arbitrarily positioned passengers. To mitigate possible risks caused by the simultaneous deployment of several big airbags, a new principle of their operation is required. Herein, the aspirated inflator for a driver airbag is developed that can provide 50L-airbag inflation within 30–40 ms. As a result, about 3/4 of the air is to be entrained into an airbag from the vehicle compartment. The process is initiated by a supersonic pulse jet (1/3 air volume) generated pyrotechnically. Then the Prandtl–Meyer problem formulation enables guiding linear and angular dimensions of the essential parts of the device. Accordingly, a family of experimental models of varied geometry is fabricated and tested to determine their operational effectiveness in a range of motive pressure within ~ 3–7 MPa. Experiments are performed on a specially designed facility equipped with compressed-air tanks and a high-speed valve to mimic the inflator operation with the pyrotechnic gas generator. The aspirated inflator operability is characterized using multivariate measurements of pressure fields, high-speed video-recording of the airbag inflation process, and evaluation of aspiration (entrainment) ratio. The average volume aspiration ratio measured at 300 K is found to reach 2.8 and it’s expected to almost double at 1200 K.