The Stirling cycle The Rider or Compression engine The Ericsson cycle The Ringbom cycle, named after the inventor Ossian Ringbom of Helsinki, Finland. Free Piston engines The Manson cycle. A valved single piston/displacer engine so called after a design by A.D Manson published in Newnes Pratical Mechanics in 1952. The design also appears in a patent granted in Germany to Michael Ruppel in 2000.