Stearns and Willys both used the Knight sleeve valve engine for a time. It's advantage was mainly quiet operation but sealing and lubrication problems did not permit it's continued success against the poppet valve. There have been a lot of sliding and rotary valve designs but as of now none have proved overall superior to the poppet valve. I personally do not believe that the valve springs account for a significant amount of the overall power loss as heating of the springs does not seem to be a problem and that is where the losses would have to go. Inertia and spring action do not in theirself represent any power loss. It should be fairly easy to measure the power taken to drive a valve train and compare various arrangements. I agree that other valve arrangements offer less restriction than the poppet valve, but the airflow in a gasoline engine is restricted by the throttle almost all the time in a passenger car engine and reduced restriction does not equal improved economy. I certainly like to see new ideas and hope this one works out.CB&Q wrote:Myu Dad spoke of a car, way back before I was born, which utilized "Sleeve Valves" which surrounded the combustion cylinder. I believe the car was the Stearns-Knight.
This system was not a "pipe dream", but actually was in production and sold to the public. I once saw a diagram of the system, long ago, but since I am saddled with "dial-up" internet service, only the truly important searches are done.
Just thought I'd throw in 2 cent's worth. CB&Q