NuVinci continuously variable transmission for anciliaries (alternator etc)

[Logic]

First a 'How it works':

https://www.youtube.com/watch?v=kVPjhmTThPo

Then ye; the engineer there saw the possibilities of using this to keep the rpms of the alternator and aircon etc constant, regardless of engine rpm.
(Well; more constant I would guess as I doubt this thing has the range to keep ancillary rpms completely constant..?)

Here's the link:
https://www.oemoffhighway.com/drivet...y-transmission

So where is this tech? Why isn't it in every new car since 2011?
(Patent price? That means we'll see it in 2031 when the patent expires)

It's available for bicycles and comes with an auto mode (electronic), so could be modded to work in a car by someone with a lathe etc and the skill.
Or one might try contacting NuVinci / Fallbrook Technologies.

Edit: A link showing alternator efficiency at various rpm and other pertinent efficiency info:
https://www.delcoremy.com/documents/...ite-paper.aspx

(I NB that a cooling air duct made out of a piece of vacuum cleaner pipe and some paper clips and Prestik or whatever is low hanging fruit)

[redpoint5]

No mention of mechanical efficiency ratio, so that's probably the killer.

[Logic]

Originally Posted by redpoint5

No mention of mechanical efficiency ratio, so that's probably the killer.

85%

https://www.cyclingabout.com/speed-d...arbox-systems/

Some of the listed gearboxes come with auto shift, which would also work.
But many of them require a break in power for the change.
That means a clutch, which would be a good thing to completely disconnect the alternator and aircon (on the drive side), from the engine.

All this ads weight, so your power to weight ratio goes down.
Less or more than you save..??
Fact of the matter is no-one has tried this, so until it is tried; we don't know.

[redpoint5]

Ouch, a traditional drivetrain on a bicycle is 96% efficient.

[Logic]

Originally Posted by redpoint5

Ouch, a traditional drivetrain on a bicycle is 96% efficient.

And an alternator is~10% more efficient at 1600 rpm exactly, if I'm reading the graph in the the linked alternator paper correctly. Do take a look.

That may not be true for all alternators, but I'm guessing; Similar graph - Different rpms..?
That's a narrow peak versus the rev range normally used in driving.
So we're back up to 95-ish %.
(Only half the amps but definitely an eco mode that would be sufficient a lot of the time.)

If the gearbox and clutch is on the driving (not driven) pulley?
People are reporting 10% with 'alternator delete' due to additionally eliminating belt inefficiency.

(If the belt's missing until you start slowing down and have energy to burn, you have the alternator delete... and free charging.)
(Naturally there are in-between settings and the battery never gets too low)

Also; if it's 'to wheel' efficiency; the bending chain/belt on teeth inefficiency of the baseline straight chain is already in that 85%.

It just adds up.
BUT
This idea's way expensive, and why start there if there's so much room for improvement in the stock alternator itself. Thinner laminates and fancy new diodes (was it?) etc.

So it's just nice to be able to go : "Hmmm!? Interesting numbers!" occasionally.

(I've expounded again! I suppose I write for all readers)

[freebeard]

...and why start there if there's so much room for improvement in the stock alternator itself.

Aren't alternators axial flux? There are advantages to radial flux. IIRC there is a third option but I don't remember the search term.

[redpoint5]

Originally Posted by Logic

And an alternator is~10% more efficient at 1600 rpm exactly, if I'm reading the graph in the the linked alternator paper correctly. Do take a look...

If the gearbox and clutch is on the driving (not driven) pulley?
People are reporting 10% with 'alternator delete' due to additionally eliminating belt inefficiency.

(If the belt's missing until you start slowing down and have energy to burn, you have the alternator delete... and free charging.)
(Naturally there are in-between settings and the battery never gets too low)

I'll take a closer look when I get a moment.

10% gain from an alternator delete depends on the vehicle. If you've got a 100 MPG vehicle, then deleting the alternator can save 10%, but if you're driving a 15 MPG pickup, the alternator load is practically nothing in comparison.

I think I've read on here there are expensive alternators that might cut inefficiency in half.

Alternators should have been eliminated a decade ago though, with hybrid motors serving the dual role of generator. Prius eliminated the accessory belt I think 2 decades ago. The best serpentine system is no serpentine system. The best part serves multiple functions.

My instinctual take is that marginally improving the horse and buggy is solving for the wrong problem.

[cRiPpLe_rOoStEr]

Originally Posted by Logic

Why isn't it in every new car since 2011?

Just look at most full-hybrids, which don't even have an accessory belt to start with.

[Piotrsko]

Um because they have a DC-DC converter? If they're running a belt drive they are doing something that is more efficient when moving than a DC pump

[cRiPpLe_rOoStEr]

[QUOTE=Piotrsko;696047]Um because they have a DC-DC converter?
That's not what I meant when I mentioned most hybrids no longer having accessory belt drives. As a motor-generator unit may be directly coupled to the ICE, sometimes even fulfilling the same role of the transmission in a non-hybrid equivalent, and some accessories being powered electrically even while the ICE is off, basically there is not much sense having an accessory belt drive.