6 stroke engine

[bruceb]

And any pump can be made to "run"- the devil is in the efficiency. Several automotive AC compressors use the swash plate style design. Free piston, extra piston, rotarys and many other designs actually can run pretty well, but can't easily meet emission standards, often as a result of too much quench area. The plain old piston four stroke is very well developed and does the job quite well with modern valve and fuel control systems. However, I still like and use small two stroke outboards for their simplicity B

[Frog4]

Larsen RADAX engine
Axial Vector engine
linear drive engine