The wear and fatigue behaviours of hollow head & sodium filled engine valve

Increasing performance of IC engines often leads to higher combustion temperatures causing premature failure of exhaust valves. This paper presents for the first time a tribological assessment of hollow head & sodium filled valves (HHSVs) produced using a new and novel manufacturing process. Tests were conducted on HHSVs using bespoke bench-top wear and fatigue apparatus and they survived defined durability tests. Compared to traditional solid valves; the highest temperature of the hollow stem & sodium filled valves decreased from 745 °C to 590 °C, the new design and manufacturing process did not adversely affect the classical wear mechanisms (e.g. oxidation accelerated adhesion) or the material loss magnitude, and the design of HHSVs gives a 16.1% reduction in mass.