Reinventing the Alternator

[James O'Neill]

I recently read a post on "How much energy does an alternator use?". So I read some more online articles and found that some people have thought of running their alternator on their drive shaft. This doesn't seem more economical to me, since you will still loose engine power .
If the alternator creates engine drag and ultimately makes the car less efficient, how can you go around this without doing away with your alternator?
My thoughts:
Instead of running your alternator off the drive shaft with a belt, why don't you make the drive shaft the alternator? You could assemble the rotor around the drive shaft and fix the stator to the chassis.
Does this idea sound plausible? Or would it make the drive shaft too heavy and ultimately make the engine even lesser efficient?

[RedDevil]

It is very feasible.

An added bonus is that the rotor can replace the flywheel.
It can even double as a motor for short bursts of EV power during EOC, prolonging coasts etc. and support/rev up the engine while accelerating hard.
Add some smart electronics and a small extra battery and you have a hybrid!

The Honda IMA system is a fine example of that setup.
Maybe you can use the motor, electronics and converter from a Civic Hybrid or Insight.

[James O'Neill]

Originally Posted by RedDevil

It is very feasible.

An added bonus is that the rotor can replace the flywheel.
It can even double as a motor for short bursts of EV power during EOC, prolonging coasts etc. and support/rev up the engine while accelerating hard.
Add some smart electronics and a small extra battery and you have a hybrid!

The Honda IMA system is a fine example of that setup.
Maybe you can use the motor, electronics and converter from a Civic Hybrid or Insight.

I also read of a Villiers bike that has its alternator on the end of the drive shaft.
Does this mean that there are already similar setups of my idea that proves its feasibility?

[RedDevil]

I found this: Alternator to a Villiers 2T

But TBH I know nothing of the subject, just that my Insight has a motor/generator instead of a flywheel and no traditional alternator.
(though it has a starter engine even when it seldom uses it)

[Daox]

Moving the alternator around isn't going to change efficiency at all in and of itself. IF you operate the alternator differently, you can probably realize some gains though regenerative braking which some OEMs are already doing. If you simply move the alternator to the drive shaft, it does virtually nothing for efficiency besides possibly getting rid of a belt which is very minor.

[Frank Lee]

You do realize that a driveshaft or d.s. driven alternator only charges when the vehicle is moving, and at significant speed at that. In the hands of the general public this will result in dead batteries (too much idling).

You also realize that non-belt driven "alternators" are not new or unique; best examples being just about every motorcycle or small engine powered piece of equipment made in the last century. In that regard, I'm not sure why automotive doesn't do something similar. Perhaps it is harder to get the needed capacity, or more expensive. But it could be that the belt drive was there already and it's easy and cheap to glom an alternator on to it.

[Daox]

Good point on the alternator RPM on a driveshaft Frank. You'd likely need to rewind it to operate at much lower rpms.

[NeilBlanchard]

This is another way to generate electricity with an ICE vehicle:

Thermoelectrics: A Lot Of Heat Is Wasted, So Why Not Convert It Into Power? : All Tech Considered : NPR

[RedDevil]

DRIVEshaft! Argh. You don't want your car to die in a traffic jam.
I was thinking about the crankshaft.

The thermoelectric conversion has not yet seen successful application in regular cars, afaik.
Which is a shame, I would really like that. But I fear the weight, cost and low efficiency is prohibitive.

[James O'Neill]

Alright, I see your points on the drive shaft alternator not working when the car isn't moving.
But in EVs there are no traditional alternators on the count that they use more power than they generate. So what if you build an alternator around the drive shaft on EVs and hybrids? Would this be an efficient way to generate power to recharge the batteries?