TAMAVS

Tribology analysis of different materials for valve seats: an experimental and numerical investigation of several materials to further develop H2 engine application

The transition towards decarbonization has encouraged the development of hydrogen (H₂) fueled internal combustion engines, opening new challenges related to the high temperatures and pressures developed in the combustion chamber, in the absence of lubricating films generated by residues of conventional combustion. Such conditions exacerbate wear phenomena, particularly on valve seats.

The project aims to characterize the tribological behavior of different materials used in valve seats, under extreme operating conditions representative of a high-performance hydrogen-fueled engine. Experimental tests, conducted with multifunctional tribometers at UniPi, will allow for the evaluation of wear, friction coefficient, and behavior at temperatures up to 500 °C, in controlled atmospheres free of contaminants.

Materials of type CUBE, COMO, and CO have been selected, capable of offering differentiated characteristics in terms of thermal conductivity and hardness at high temperatures. The tribological analyses, which involve real pairings between machined valve seats and pins with stellite coating (as applied on exhaust valves), will be conducted both in pin-on-disk mode and in oscillating motion, with the possibility of controlling temperature and relative humidity thanks to heated modules and closed-loop systems.

To support the experimental campaign, a predictive FEM model will be developed, in collaboration between Ferrari and UniNa, aimed at estimating the wear rate as a function of local operating conditions (contact pressure, sliding speed, thermal deformations). The iterative numerical model will be based on the evolution of the product pV and will allow for predicting the growth of wear of the valve seats over time, integrating the experimental data obtained from a single-cylinder and from a test bench.