How do the piston rings get lubricated?
It will not be possible to lubricate the piston rings with liquid lubricants, therefore they will be made from self lubricating materials. Fortunately, advances in recent decades in the field of tribology have resulted in PTFE materials that have been successfully used in compressors and in stirling engines that operate at high temperatures for long periods without lubrication. Also, keep in mind that there are no piston sidewall forces acting on the piston rings in the PC2S engine and the rings will not be directly exposed to the combustion process.
