Air turbine/compressor regenerative braking/ cruise control!!

[stovie]

I've been thinking of taking some 2 inch drill pipe to make into adriveline for my s10. At which time I would like to take some 3/4 to 1 inch steel pipe to cut in halves to use as 1 inch wide fines for a air turbine to drive the driveline under light loads like cruising on the highway, or regenerative braking around town!!

For the compressor part I'd like to offset two 4-6 inch wide rotor type compressors!! Looking into it I could by a couple feet of different size pipe and weld this together pretty easily!?!

https://m.youtube.com/watch?v=b2fen0tI3oI

https://m.youtube.com/watch?v=fxDEK3Ymx30

[oil pan 4]

Air motors need a lot of air and they don't do a lot of work.
Air compressors and air motors need to have pretty tight clearances to work at all.

[JRMichler]

If you use good components, it takes about 4 hp to the compressor to get 1 hp out of an air motor. Home made compressors and motors will do far worse.

It's because of the laws of thermodynamics, specifically adiabatic vs isothermal compression and expansion.

[acparker]

Hydraulic hybrids are essentially compressed gas hybrids, as the "spring" in the system is compressed nitrogen or air. It may be that a hydraulic pump/motor is more efficient at converting pressure into motion (and vice versa) than an air pump/motor.

[JRMichler]

Hydraulic pumps and motors can be over 90% efficient near their best efficiency points. The accumulators in a hydraulic hybrid are sized such that the air compression and expansion is nearly isothermal. The result is that system efficiency can exceed 75%.

[acparker]

I was extremely disappointed that Citroen's parent company chose to scuttle the Air Car, their hydraulic hybrid that was to have been marketed last year (iirc, the entire hydro-pneumatics engineering department was sacked as well). All Citroen's are now just rebadged Peugeots. Unfortunately, cutting-edge engineering and design usually bleeds money, so I can't really blame them for the business decision.

[stovie]

I'll be using a rotary compressor, reducing a lot of the "pumping losses" of a regular compressor!! The compressors going to have around 100-200 cubic inches of displacement while the "motor" will only have about 2-3 inches!! I also have a plan to test out having a "turbo compressor" as a pre-compressor to supply air at higher than atmospheric!!