The Manson cycle engine was designed back in 1952 by A.D. Manson and first published in Newnes Practical Mechanics March 1952 p193. Here a drawing form the original publication:

Michael Ruppel slightly modified Manson’s idea

and built this engine:

A nice drawing of Manson’s engine concept I found on Walter Haag’s web page, who built a replica of the Manson/Rupp engine.

Interesting links:
http://www.geocities.ws/kenboak/Manson.html
http://www.w-haag.de/mansonstirling.htm
Patent of Michael Ruppel of a modified Manson engine – DE 19904269A1

I will explain my motivation of dealing with this engine type soon. So more is coming …