This is called a
Swing Piston Engine I think.
Another concept I saw in the 80s was basically a regular engine, but bent into a circle so both ends were touching each other. Since a cam shaft no longer works when it is bent, the reciprocating action of the cylinders was achieved by a drum that had a profile of a sine wave around its circumference. This gave the up/down motion that the camshaft normally provided. the valves worked in the same way.
I used to be quite excited by this concept, but the lack of interest and no working prototype of note yet makes me wonder.
![Image](http://www.regtech.com/images/finalengine_320x240.gif)