Pneumatics Blog

I think the scroll expander guys may have a real chance at getting bought up by some corporation and then having their work buried before it ever gets to a large scale market application.

Its too practical and has realistic applications that can in fact benefit from such a device. That alone will get the attention of the greedy giants that seem to always buy up and bury new tech that works!

The piston air motor guys seem like a typical college level machining lab project to me. All of their fancy electronic valves and timing can easily be installed right on a standard issue automotive engine just by using a different head design.

Unfortunately there is still that real life problem of the physics that says compressed air tanks just don't hold enough power to drive a decent sized vehicle fast enough and far enough to be practical at any realistic tank pressures. The compress and decompress energy looses cant be recovered effectively on a vehicle application. In a stationary application they can be.

For stationary applications where tank size is not a problem they clearly have some real beneficial short term operation applications but for vehicles the practical portability and realistic efficiency issues still have not been solved.

I agree with you, until a better method/price is found to get the air compressed, there is little or no chance of acceptance, simply too inefficient.

I belive more in supercapassitors

Hello temtrech,

The scroll expander has sliding motion on many hard to control surfaces which may be its biggest drawback. I don't share your enthusiasms on that one.

The scroll compressor system was used by Audi as a supercharger but only for a little while (a few years) until it fell out of favour. I would not hold my breath for that one.

VW too. If you have one of them go wrong today, only some third party suppliers in Germany can help, VW not anymore....

I agree Andy, yes VW more so than Audi.

That should give some answer to the question of its viability.

Dead right!

Actually I am not all that enthusiastic about it. I just think its an interesting way to make an air motor. And scroll compressors are known for being slightly more energy efficient in their ideal operating range and working conditions or atleast thats what was taught to me. Plus they do have fewer moving parts.

The very rapid response times and clean method of operation and energy storage concepts are more interesting to me than anything else.

But yes its too early to tell if this scroll expander concept will catch on.

I think the rapid response time comes from their small rotating moment of inertia. The weight of the rotating body is low and mainly the radius is very small, resulting in low kgm^2, hence fast acceleration and quick response.

For the same reason they run generally at high speeds which is not so good for wear and noise. All in all the turbine is still the better bet for charging engines. Turbines run even faster and therefore can be made smaller in overalls size.

For other applications the scroll compressor might do its job. It all depend where and for what purpose it is going to be used.

One of the most impressive 'air motor' configurations I have seen was a motor & IC engine that was displayed and actually won a NASA first place award several years ago called the MYT Engine ( Mighty Yet Tiny Engine ) designed by a Mr. Raphial Morgado.

I was hoping it would be funded soon but he had some internal executive management problems with some of the people he hired and they squandered away and mis-managed his assets terribly.

The principle of the pistons working together is nice, it has been around since the 1960's. See also Kauertz, Virmel (from Virginia and Melvin Rolfsmeyer) and a slew of others. It might work ok as an air compressor or pump. In ICE application the linkage may not stand up too well.

I was not aware that the MYT engine Raphial Morgado had (mis-)management problems. Things like that are too common. Does he get new funding?

Earlier this year I heard he is going into production. May be not yet.

I'm using two 3200 PSI scuba tanks with a 5 gallon piston accumulator for hydraulic launch assist and braking regeneration. Works great, weighs 280 lbs.