cogeneration

[dukedesmo]

has anyone tried to hook up a generator to a 5 wheel to generate electricity to eliminate alternator?

[GasSavers_RoadWarrior]

In my opinion, that would be less efficient than an alternator, because the power needed to drive it would be subject to transmission losses, instead of coming straight from the engine and the wheel would cause aerodynamic losses.

[kamesama980]

yea, it'll be less efficient and have 5x the parts to maintain.

[DarbyWalters]

You would need to figure out a way to make it part of one of the four wheels you already have on the ground...or something else that is already turning like a driveshaft ect.

[GasSavers_RoadWarrior]

Even then, if it takes 2HP to turn an alternator off the engine, and transmission loss is 15%, then it takes 2.3HP at the engine to turn it off a roadwheel.

Better way is to use wasted energy, heat, or exhaust momentum, pyroelectric generator, or turbine, conventional or tesla type on the exhaust. Could probably find a way to run a small stirling cycle motor off exhaust heat to drive an alternator.

[DarbyWalters]

Maybe something "wind powered"?

[GasSavers_RoadWarrior]

Maximum efficiency of an impeller is about 85%, then there's parasitic aero drag off the installation as well as the 2.3HP worth of induced drag that you're making power from. So by then you need about 3HP more at the engine to drive your 2HP worth of alternator.

[lunarhighway]

the weight might undo the benefits but what about a small stirling engine driven by exhoust heat? this woud add 0 drag and would recycle other wise wasted engergy? .... of course than a full stirling-electric hybrid would be great... in theory it could run on anything that burns and the electric motors would cover the warm up time the stirling engine needs

[GasSavers_Glacial]

Hm, a turbine spun by a liquid that will phase-change between ambient and exhaust temperatures could generate some power.

Exhaust manifold for evaporation, radiator for cooling, turbine in between. Shouldn't be too hard.

[GasSavers_RoadWarrior]

Could probably do it with a closed loop steam system, might take a few miles to get going though. Which means you need to lug around a largish battery. Wonder if you could have a vacuum bladder that is strong enough to pull the pressure in the system low, such that the water will flash boil at lower temperatures during warm up.

Edit: one might be able to arrange it with check valves such that it pulls low on cooldown, but that would presume that it got up to working temperature every trip.