Rotary Valves Make Normal Valves Look Silly - Why Aren’t We Using Them?

Four stroke engines, which is what 99% of the engines on the road are, need to let air in during intake. The combustion chamber must be sealed during compression and combustion and we must let air out during the exhaust. This means that we need a system that can seal and unseal the chamber thousands of time per minute while at the same time withstanding the incredibly harsh conditions present in the combustion chamber. And this is exactly what poppet valves do. They are great at sealing the chamber because the conical shape of the valve face fits into the conical shape of the valve seat creating a positive seal. Both the face and seat are made of hardened metals which offer impressive resistance to wear and increased temperature. As compression or combustion pressure acts on the valve head it actually pushes it harder against the countersunk seat. The greater the pressure the better the seal. Unfortunately other than being great at sealing the chamber poppet valves realistically don’t have any