We haven’t looked at any new internal combustion engines for a while and I just spotted this one, the Circle Cycle engine. It’s described as an orbital, non-reciprocating internal combustion engine, having pistons and cylinders and able to run on a variety of combustible liquids or gasses. It has no engine block, no crankshaft or connecting rods, no separate flywheel, no intake or exhaust valves, no water pump and no radiator or any of the hardware usually associated with these items.

The engine uses direct injection of fuel into the center of the combustion chamber and it can be configured to run as either spark ignition or diesel. Potential applications, according to the website, are pretty much what you would expect, which is anything you would use any other internal combustion engine for.

The company has been developing the engine for five years and believes it is at the stage where it can be taken to the next step, which is design and production for specific applications, so they are looking to sell or license the patent or enter into a joint venture with someone who can carry it forward.

The only part of the design I question is the gearing necessary to keep the cylinders and pistons in alignment while the large geared wheels are turning. Any hiccup in operation or broken tooth on one of the gears could result in catastrophic failure, but they may have addressed that somewhere in the design and it may be more apparent if we were to see the actual engine up close.

There are a lot of photos, drawings and animations on the site plus a great deal more explanation of the concept. Is it better, more efficient or in some way an improvement on what we already have? I can’t say, but it’s pretty ingenious and cool to watch in operation, just the sort of thing any gearhead should enjoy.

Link: Circle Cycle

Animation and videos below:

Animation to show the process.

Prototype hand cranked in slow motion.

Prototype running on propane.