One afternoon, while bicycling up (yet another) hill, I thought how much fun cycling would be but for the friggin' hills! And, rather than adapt myself to the reality (I live somewhere hilly), I chose to adapt reality to me! Specifically, I wanted to create a temporary storage device that would gather excess energy on downhills and return it on uphills! Since lead-acid batteries are heavy, bad for the environment, and tend to corrode bike frames, I considered air. Simple enough--capture energy on descent; return it on ascent. I just need someone knowlegable enough to crunch the numbers. Minimum requirements would be: get me, bike, cargo, and engine (call it 275# total) up a 400', 8% grade at 15 mph, with me pedaling just as hard as on level ground. Well, 15 mph is 22fps, of which 1.76 fps is straight up. Dividing by 2, we need 0.88hp (0.66 kW) output for 227 sec, for 0.047 kW hr (0.063hp hr?) storage capacity. So, what I'd like to know is 1. where might I find a not-quite 1hp air engine? 2. Would an old propane grill tank at <= 200 psi be sufficient storage capacity? (I plead ignorance on how to convert psi into hp or kw...sorry!) Note that this avoids the main complaint of batteries/fuel cells/etc because the "ultimate source" of the energy is STILL me; I'd just effectively make the terrain behave as if it were less hilly than it actually is.
I know this isn't what your looking for, but I thought what Trondheim, Norway did was pretty cool. https://www.youtube.com/watch?v=7j1PgmMbug8
Well that sounds like a good idea but you will need to invent it first. A compressed air engine might help(propane or other air tank) but you will need to create a nozzle similar to a rocket engine nozzle. That won't help with gathering air on the downhill side; it will require a compressor with a power source, otherwise it will not capture enough air. That pesky 2 law of thermomechanics just keeps getting in the way. Unfortunatly if you don't happen to live in Norway a electric bike is still less polluting than anything else, other than what you are doing already!
how about a reversible piston pump engine? engage it on the downhills so that your pedaling fills the tank and on the up side reverse it so that the air that just filled the tank now turns the pistons. of course the engine is disengaged on the flats. this sounds heavy.
i was thinking about your idea earlier today and that idea just might be plausible as a assist while pedaling but i do not see there being enough power to fully drive the bike up a hill and i was also thinking of a reverse piston pump zenloki
