Vacuum is a good idea. What kinds of pumps could be found easily to pull a vacuum on steam, though? I mean, the engine produces tons of vacuum, but then it would pull all the steam through the intake which is probably not good. I'm wondering if a washer fluid pump would be able to put up with that kind of temp or even be able to pull enough.
On a side note, I was able to get an old 2-stroke to turn over on air earlier, so I'm gonna high-tail it over to home depot/radio shack to grab a reed switch and solenoid valve to see if I can get it running on compressed air, then on steam. Seems pretty doable, though those solenoids have a short life. Once I have it running on steam, I'll get some pics/video and try to get it turning an alternator or whatever I have around to bog it down. Baby steps, though. Today I'm going to try to get it running on compressed air.
So, I'm looking through my thermodynamics text book at the saturation values of water, r-134a, and r-410 and at 190F, 134a has a saturation pressure of about 450 psi. My table for 410 stops at 160F, but it's pressure is 710 psi. Water at boiling is only 14 psi. I'm probably wrong in inferring that this means a similar volume of liquid refrigerant would produce a lot more pressure, so I'll have to discuss this with my thermo prof, but it's something to take note of. Especially since I think get oil into that sort of system for lubrication would be a lot easier than using steam oil and trying to deal with emulsification.
Let me hear some thoughts on this from all the engineers that lurk on here
