carguy123
carguy123 PowerDork
10/30/12 8:09 a.m.

http://www.stangtv.com/videos/tech-videos/power-adders/procharger-introduces-revolutionary-programmable-ratio-supercharger/

Looks like CVT to me.

GameboyRMH
GameboyRMH PowerDork
10/30/12 8:17 a.m.

Yep a centrifugal supercharger driven through a CVT. Actually a really good idea, this fixes the big problem of superchargers, which is that they only respond to RPM. With a TPS input it can respond to load irrespective of RPM, or just run at the highest possible boost all the time.

erohslc
erohslc HalfDork
10/30/12 8:19 a.m.

Yup. Now we just need someone to put CVT between the wheels of a turbo. Run the exhaust side and compressor side at optimal RPM's independently. No more wastegate, uses heat energy that is otherwise wasted instead of vampiring off off the crankshaft.

alfadriver
alfadriver PowerDork
10/30/12 8:33 a.m.

Better not have a patent on that, as I wrote a paper with that idea way back in 1990. Although, my idea was a little more- use the CVT not just to control boost, but as a throttle- where you extract a little bit of the pumping losses back out of the CVT.

It would not be much, but better than nothing.

(Prior art trumps patent application)

GameboyRMH
GameboyRMH PowerDork
10/30/12 8:34 a.m.
alfadriver wrote: Better not have a patent on that, as I wrote a paper with that idea way back in 1990. ... (Prior art trumps patent application)

Hahaha I love your idealism.

alfadriver
alfadriver PowerDork
10/30/12 8:34 a.m.
erohslc wrote: Yup. Now we just need someone to put CVT between the wheels of a turbo. Run the exhaust side and compressor side at optimal RPM's independently. No more wastegate, uses heat energy that is otherwise wasted instead of vampiring off off the crankshaft.

Not a bad idea. but how to implement that at over 100k rpm and the smalll power that the turbos operate would be a cool mechanical trick. Something to develop.

alfadriver
alfadriver PowerDork
10/30/12 8:35 a.m.
GameboyRMH wrote:
alfadriver wrote: Better not have a patent on that, as I wrote a paper with that idea way back in 1990. ... (Prior art trumps patent application)
Hahaha I love your idealism.

I certainly would not hesitate to try the technology without "permission", that's for sure. It's not new.

DaveEstey
DaveEstey SuperDork
10/30/12 8:37 a.m.

I prefer this method of constant boost:

http://www.youtube.com/watch?v=11687nVdzdk

GameboyRMH
GameboyRMH PowerDork
10/30/12 8:55 a.m.
DaveEstey wrote: I prefer this method of constant boost: http://www.youtube.com/watch?v=11687nVdzdk

I wonder if it would make more sense to use a (serious) electric supercharger...a second heavy-duty alternator and big electric motor and gearbox probably weighs less, and is much simpler.

Edit: I get that the APU is better for race use and more powerful overall since it's not taking any power from the engine, but it would be horrifically wasteful and complicated for anything but a pure race car.

dinger
dinger Reader
10/30/12 10:00 a.m.

Don't Roots style blowers already make constant boost? At least, the TRD one I had in my 4Runner did.

Seems like a lot of added complication just to make a centrifugal blower work like a roots blower already does.

GameboyRMH
GameboyRMH PowerDork
10/30/12 10:05 a.m.
dinger wrote: Don't Roots style blowers already make constant boost? At least, the TRD one I had in my 4Runner did. Seems like a lot of added complication just to make a centrifugal blower work like a roots blower already does.

No the boost is directly related to engine speed on that kind of blower. With the CVT supercharger you could make an absolutely constant amount of boost, where it is at the same level regardless of engine speed, or you could get a great deal of boost at low revs and have it taper off to a safe level as revs increase - like running a huge pulley at low revs and a smaller one at high revs, meaning relatively low variance in the level of boost.

yamaha
yamaha Dork
10/30/12 10:06 a.m.

In reply to dinger:

Nah, toyota just rigged up your boost guage to read constant......prolly didn't even put the s/c on it, just a cog drive belt setup to whine......

KATYB
KATYB Dork
10/30/12 10:08 a.m.

i think alot of wanting the centrifugal is for the reason of packaging its alot easier to package a centrifugal blower into a vehicle. less oart engineering and also some modern vehicles do not have the hood clearance (that extra 1 or 2 inches of a blower on top of the engine) to fit one under the hood. i personally like this idea.

KATYB
KATYB Dork
10/30/12 10:10 a.m.

also i like that u can change the boost amounts without having to change the pulleys out. ie ok going to the track wanna run race gas and up the boost ok fine fill up push a button and ur done. sure beats the alternative.

erohslc
erohslc HalfDork
10/30/12 10:13 a.m.
alfadriver wrote:
erohslc wrote: Yup. Now we just need someone to put CVT between the wheels of a turbo. Run the exhaust side and compressor side at optimal RPM's independently. No more wastegate, uses heat energy that is otherwise wasted instead of vampiring off off the crankshaft.
Not a bad idea. but how to implement that at over 100k rpm and the smalll power that the turbos operate would be a cool mechanical trick. Something to develop.

I assume that you are worried a CVT could handle 100K shaft speeds?

But the centrifugal SC (with or without CVT) must already step-up crankshaft speeds to turbo speeds (the compressor section is basically same as a turbo), a not insignificant task.

So one brute force approach would be to simply reduce the exhaust turbine speed to crankshaft speed (for benefit of the CVT), a much simpler task.

Carter

GameboyRMH
GameboyRMH PowerDork
10/30/12 10:18 a.m.

I figured it's nothing a couple of gearsets (like the one already on the turbine side of this thing) can't handle.

But hang on a minute, does a CVT turbo make more sense than a variable-vane SSVGT?

erohslc
erohslc HalfDork
10/30/12 10:20 a.m.
GameboyRMH wrote:
dinger wrote: Don't Roots style blowers already make constant boost? At least, the TRD one I had in my 4Runner did. Seems like a lot of added complication just to make a centrifugal blower work like a roots blower already does.
No the boost is directly related to engine speed on that kind of blower. With the CVT supercharger you could make an absolutely constant amount of boost, where it is at the same level regardless of engine speed, or you could get a great deal of boost at low revs and have it taper off to a safe level as revs increase - like running a huge pulley at low revs and a smaller one at high revs, meaning relatively low variance in the level of boost.

Roots (positive displacement) supercharger output volume is (approximately) proportional to RPM. And engine volume is also (approximately) proportional to RPM.

So in a roots system, the boost pressure IS approximately constant over RPM, determined by pulley ratio.

But the OP refers to a centrifugal SC, not positive displacement.

Jaynen
Jaynen HalfDork
10/30/12 10:23 a.m.

Audi already has a true electric turbo doesn't it?

erohslc
erohslc HalfDork
10/30/12 10:28 a.m.
GameboyRMH wrote: I figured it's nothing a couple of gearsets (like the one already on the turbine side of this thing) can't handle. But hang on a minute, does a CVT turbo make more sense than a variable-vane SSVGT?

Gearsets that perform a large speed step-up suffer some issues. The parasitic friction on the output (high speed) side is multiplied by the step-up ratio (bad). Whereas in a speed reducing gearset, parasitic friction on output (low speed) side is reduced by the step down ratio (good).

I belive that you will find that the dynamic range of a variable-vane SSVGT is limited compared to an equivalent CVT, and that efficiency is not as good.

But we don't have an actual turbo speed CVT to compare and measure.

Carter

erohslc
erohslc HalfDork
10/30/12 10:43 a.m.
GameboyRMH wrote:
DaveEstey wrote: I prefer this method of constant boost: http://www.youtube.com/watch?v=11687nVdzdk
I wonder if it would make more sense to use a (serious) electric supercharger...a second heavy-duty alternator and big electric motor and gearbox probably weighs less, and is much simpler. Edit: I get that the APU is better for race use and more powerful overall since it's not taking any power from the engine, but it would be horrifically wasteful and complicated for anything but a pure race car.

The power density and efficiency of an electric driven SC work against it. A starter motor makes about 1-2 HP, and is only that light because it is designed to perform for a few seconds at full load. A SC can require continuous 25-50 HP, and the motor must be rated to perform continuously at full load.

Have you ever seen a commercial duty 50 HP electric motor?

Diesel electric locomotives can get away with it because scaling up works in their favor, and the weight at that size is not such a penalty.

The newer rare-earth magnets, advanced winding methods (thin film, coreless rotors, etc.) and control electronics make this size of electric motors more viable for automotive use. Perhaps they can even employ the multiphase AC technology used by hybrid/electric cars instead of DC.

Personally, I think that there is a lot of efficiency to be had by running an efficient high speed alternator off of an exhaust gas turbine, perhaps colocated on the same shaft as a conventional turbo.

codrus
codrus Reader
10/30/12 3:55 p.m.
dinger wrote: Don't Roots style blowers already make constant boost? At least, the TRD one I had in my 4Runner did. Seems like a lot of added complication just to make a centrifugal blower work like a roots blower already does.

Yes, roots and twin-screw blowers make roughly constant boost (the seals are imperfect, so you lose some of it at lower RPMs), but the efficiency of the compressor is significantly less than that of a centrifugal compressor, and they tend to be bigger, heavier, and more expensive to manufacture.

alfadriver
alfadriver PowerDork
10/30/12 4:37 p.m.

In reply to erohslc:

You make it sound so easy- should be a fun project for you to try.

But I don't see it being all that great- particularly for response. The straight shaft set up allows for as little mass as possible, which lets the wheels speend up quite quickly. Any mechanism that you put on there will dramatically increase the rotating mass, which will slow down turbine spooling.

It's a lot easier to deal with in a brute force manner for a engine driven compressor.

Variable vane worked quite well, technically. Just didn't last long enough.

And I don't think Audi has a electric turbo. Electric assist- perhaps. But not pure electric driven.

erohslc
erohslc HalfDork
10/30/12 6:40 p.m.
alfadriver wrote: In reply to erohslc: You make it sound so easy- should be a fun project for you to try. But I don't see it being all that great- particularly for response. The straight shaft set up allows for as little mass as possible, which lets the wheels speend up quite quickly. Any mechanism that you put on there will dramatically increase the rotating mass, which will slow down turbine spooling. ...

Are you referrring to the turbo driven alternator? That one has already been done, so far on relatively constant speed applications.

But the high RPM of an auto turbo means high frequencies, which enable very lightweight magnetic and electrical components. For example, high frequency (>>20 KHz) switching regulators and components used in modern electronics feature tiny, tiny ferrite core transformers.

And the rotor for a high frequency turbo alternator need not contain any iron at all. A thin disk of fiberglass/epoxy acts as mechanical support, with the 'windings' formed by the etched pattern of the copper cladding. It's old technology, the pancake motors used in radiator fans are built that way. Kolmorgen used to make multi-HP motors that way. The rotational inertia of such a rotor is insignificant compared to the turbines.

Modern power control electronics, with software, would enable such a setup to be seamlessley integrated with modern cars electrical systems. Instead of wastefully controlling the turbine RPM by blow off or bypass, it can be controlled by increasing the charge rate of the turbo alternator. This can be accomplished either by controlling the excitation current in the field winding, or if permanant magnets are used, by direct pulse width modulation of the output current from the rotor.
In theory, the same rotor could even be used briefly as a motor, to help spool the turbo more quickly.

Considering the extermes that OEM's are going to meeting CAFE standards, this looks like low hanging fruit to me, especially if the vehicle is already fitted with a turbo (Ford, are you listening?).

(Sorry, guess I kind of went on a rant there.)

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