Effect of lubricant oil composition on hydrogen auto-ignition in a heated constant-volume autoclave

This study examined the impact of the base oil and additives in formulated lubricant oils on the ignition behavior of hydrogen. The minimum auto-ignition temperature (AIT) was measured using a heated, constant-volume autoclave at 20 bar. Four fully formulated lubricant oils (Oils A, B, C, and D) with different additive compositions and base oils were tested to evaluate their influence on hydrogen ignition. The focus was on additives containing calcium (Ca) and magnesium (Mg), as these elements are known to affect pre-ignition. The study also investigates the individual effects of Ca and Mg additives in base oil. Ca-based additives are known to be strong promoters of pre-ignition, while Mg-based additives tend to have no effect. However, the results indicate that the Ca-based additive has no significant effect, while the Mg-based additive has a minor inhibitory effect, on hydrogen ignition behavior in the heated constant-volume-autoclave. Base oil, on the other hand, has a greater influence on H₂ ignition. The results also show that different lubricant formulations have different auto-ignition characteristics. Lubricants with a full package are more resistant to auto-ignition. Among the lubricants tested, the ester-based formulation exhibited the highest AIT, while the lubricant oil had a lower tendency to auto-ignite under hydrogen-rich conditions.