Turbo power

The earlier post on turbos reminded me of an idea I had:

If an exhaust driven turbine was used to drive a car's alternator instead of using a belt, would it be any better or worse in terms of using the engine's power?

I mean, the turbo effectively makes use of 'lost' power so I idly thought it would be more efficient.

Reply to
Mark W
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nope

Reply to
Theo

yes

Reply to
Tony Bond

maybe

Reply to
Andrew Ratcliffe

you have answers ranging from nope to yes to maybe ;)

it's a grand idea, but how would you stop the heat from causing problems? I can understand if there was a way for the boost produced to spin up an alternator, that could be looked into, but direct from the exhaust wouldn't be such a great idea and what if you were on idle all the time? turbo's produce boost under load so you need to drive the car to get it to make any power

Reply to
dojj

I've been thinking about this sort of thing for a while off and on, when I'm bored. And I came to the conclusion the best thing would be some sort of heat > electricity conversion, presumably using a chemical reaction. But I'm buggered if I know if it's possible!

Reply to
Stuffed

Something akin to a solar panel, using the heat difference between coolant and air would work. And that's all free energy. Good thinking. Stuffed.

Reply to
Sales!

Heat to electricity is easy, use the exhaust gasses to heat a water reservoir and use the steam from this to run a small steam engine which can drive an alternator. Obviously the water would need to be kept topped up but at least it's free.

Reply to
Homer

That'd be the main problem - if someone does a lot of town driving. Maybe some sort of cog driven alternator that only engages at idle speed - shouldn't have thought it'd have too much of an effect on fuel consumption at idle speed. Just an idea. Probably a terrible one.

Peter

Reply to
AstraVanMan

In article , snipped-for-privacy@WithThanks.com spouted forth into uk.rec.cars.modifications...

Quite a sound one actually.

How about standard belt driven alternator, with some sort of clutch/free wheel in the belt wheel.

At low revs/idle the belt drives the alternator, at higher revs when the turbo is spooled up, a rod conecting it to the alternator turns the alternator. A side effect of this may be that the alernator belt drive may actually keep the turbo spinning when off the gas liek a supercharger? Engine driven till spooled?

Reply to
MeatballTurbo

speaking to someone yesterday they said it needed to be the same thing as the car needs like AC rather than DC or something and this method wouldn't do the job because of that or something what really needs to be done is to have some way of disengaging the pulley in the same way as the AC pump clutch that way you only get it used when you need to charge the battery

ok, a failure would be the end of the day for you, but why not?

Reply to
dojj

In article , snipped-for-privacy@fsnet.co.uk spouted forth into uk.rec.cars.modifications...

Well, and alternator provides DC and is belt driven, so if it was belt/clutch/turbo output(PTO) shaft driven.

biggest problem I can see is, to keep the alternator cool, you would need to have a long shaft from one side of the engine to another, that could lead to wavering in the bearing of the turbo, and eventually destroy is as the bearing breaks down from the the extra load.

Reply to
MeatballTurbo

In article , snipped-for-privacy@fsnet.co.uk spouted forth into uk.rec.cars.modifications...

Shaft from turbo to alternator belt pulley. Shaft goes through pulley, pulley has a free wheel within it like a bike sprocket freewheel.

When turbo isn't spooled up, the belt is turning off the crank end, and turning the shaft. When the turbo spools up and accelerates past the speed of the belt driven pulley, the centre section freewheels away.

Would maybe need some kind of gear mechanism from the end of the shaft to slow the speed of the alternator when usign the turbo to turn it.

Reply to
MeatballTurbo

We're getting a bloody complicated alternator now. Wonder how long before the increase in weight and frictional losses cancel out any advantages over a boggo one?

Reply to
Doki

On a modern car, you can't anyway, because the EMS can't control the engine when the battery is flat and bump starting is no longer an option.

Reply to
Sales!

Peltier effect heat pumps can do this. Heat one side cool the other and they make a small amount of energy :) it is small though!

Reply to
Ed

Its quite a good idea, however, the power the turbine could produce is way in excess of what you would ever need in a car, think in excess of

20Kw hahaha, thats in excess of 1600 amps! Imagine the size of alternator you would need, oh and the insane reduction gearbox. It would be a good idea for a constant rpm engine, and could work in some cases, but for a car it wouldnt be ideal.

Ed

Reply to
Ed

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