Study on failure mechanism of ferrule sealing for fuel cell vehicles under low-temperature environment

Historically, few studies have examined sealing failure in twin ferrule pipeline fittings under extreme temperatures. This research investigates their sealing performance in onboard hydrogen systems under such conditions. Experimental results revealed divergent low-temperature sealing behavior: one fitting showed no leakage, while the other leaked 100–200 ppm. Material analyses indicated that surface processing quality influences sealing but is not the decisive factor. Instead, the material mismatch between the front ferrule and the joint body was identified as the primary cause of sealing failure from room temperature to low temperature. Finite element method (FEM) simulations at 19.85°C and -40°C confirmed experimental findings. To reduce hydrogen leakage in fuel cell vehicles at low temperatures, the study recommends using consistent materials for the front ferrule and joint body.