Electric Supercharger?! (adaptable for fuel economy?)

[niky]

If you like classic Niven, you should pick up Rainbow Mars. Collects all the old Time Traveller stories and binds them together with a Martian epic that includes all forms of fictional Martian known to man (except Bradbury's), a Beanstalk (both the literary and the sci-fi kind) and time travel. Great read.

-

It even has unicorns.

[Domman56]

I don't see this being too beneficial at all. POSSIBLY in bottom end when you are accellerating, Like others have said the PSI can help slightly but i did read that hotrod issue with the leaf blowers and Once higher up in the rev range the leafblowers were virtually useless they only really seemed to help near the bottom/middle and that's something that can put out a large amount of PSI

[user removed]

Green Car Congress: CPT launching water-cooled electric supercharger for commercial diesel engines

regards
Mech

[pete c]

Turbo chargers are pertty much a no-brainer for diesels. I could see some sort of electric supercharger working for brief periods. I could also see it being used as a means of recovering energy during braking.

You take an engine running at decent rpms, cut the fuel, open the throttle wide and let the electric turbine windmill. Not sure how much energy it would recover, but, it could be something. I could also see where it might work as a throttle during steady state cruising. Once again, you open the throttle wide and use the turbine as a throttle by varying the regenerative drag. This was discussed a while ago. I couldn't see it having the response to work as the only throttle, but, perhaps in conjuction with a traditional throttle.

[Frank Lee]

Originally Posted by Old Mechanic

Green Car Congress: CPT launching water-cooled electric supercharger for commercial diesel engines

regards
Mech

The aim with Cobra was to develop a 24 volt electrical supercharger to eliminate transient turbo lag, in other words be active for a few seconds or more but sufficiently robust to do so repeatedly without any thermal management issues...

The torque increase and transient response with Cobra also provides a cost-effective alternative to expensive variable geometry turbocharging by simply combining the electric supercharger with a standard, lower-cost, fixed-geometry turbocharger.

Looks like they're going through all that trouble just to reduce turbo lag, by ADDING the electric unit IN ADDITION TO a standard turbo.

I didn't know turbo lag was still such an issue? And that the electric system can be more cost effective/compact/efficient/simple than a variable-geometry turbo?

[niky]

Cheaper? Debatable. But at least not using variable geometry on the main turbo makes it more robust. Variable geometry turbos are finicky things, and more vulnerable to coking and hydraulic oil-feed failures than many people are comfortable with.

I'd have thought a simple supercharger for twin-charging would be better... but having a standalone electric supercharger would make for much simpler plumbing and installation than twin-charging.

[kah]

Some Aussies (Mighty Car Mods) recently tested an electric supercharger, though for power improvement, and found no improvement. Based on their conclusion, i don't think it would help FE at all.

http://www.youtube.com/watch?v=cbGWg...feature=showob

Their other videos are also very interesting and enjoyable.

[metromizer]

Reading this thread is a hoot... there is so much misinformation floating around regarding supercharging it isn't funny. The confusion happens because of clowns who try to sell snake oil by calling a $69 12v squirrel cage fan with some flexible dryer ducting an zip ties '12volt supercharger kit' Something for almost nothing... Hmmmm... too good to be true.

Real honest to God engineered turbocharge and supercharger systems cost thousands of dollars to do correctly. They also take power, lots of it to drive. Anyone ever watch NHRA drag racing, the 8000hp top fuel cars? I've had the good fortune to crew on one of those teams. If I remember right, those superchargers take something like 700hp to turn at the speeds they need to supply 55psi of boost to a 500cu in engine at 7500rpm. If you see a 'street car system' for a 2liter that claims to give even 6psi of boost, but draws less than several hundred amps to drive, be suspicious, very suspicious.

Back to the original posters question/idea: I could see some merit in overall FE if a 'part time' system were employed, on demand supercharging'. When I say overall, I mean using an undersized power plant for the vehicle, say a 1liter in a 2800lb car, 60hp on a good day. Most would never have the patience to drive something like that (most of us on this forum, excluded) but it could get fantastic FE while cruising in that little 1liter's 'sweetspot' . Then use an 'on demand' supercharger to help add 40% more power temporarily, you get up to highway speeds. While in temporary supercharged mode, 8-14 psi, FE would be awful, but you make it up while cruising more efficiently, 90% of the time.

You'd really need to engineer such a system to make it work for FE, would need to increase fuel flow rates and limit ignition timing advance under boost conditions (as to not lean out the engine and melt the ring lands) but this stuff isn't new, an aftermarket programmable ECM would handle this chore. If you chose electric (see link below, an example of a real electric supercharger that supplies power increasing boost).

Controlled Power Technologies... VTES

You'd need several extra 12v batteries that could quickly discharge as much as 350amps into the supercharger motor, than have an alternator of sufficient size to re-charge those extra batteries during cruising. The bigger challenge in a retrofit system would be managing incoming air flow under both conditions, blown, and high efficiency normally aspirated. In the electric supercharger in the link above, it looks like they slow the rpms down during non-boosted operation, drawing only 1.5amps. Mercedes has/had a part time belt driven supercharger system, that manages this airflow problem somehow. Some type of flapper door that toggles between one incoming air route to the other?

[ecomodded]

Haha a hoot for sure, i have washed a few videos from those two "testers" in the past.
The twin leaf blower turbo has hilarious.
Once they tested a start button install, only to find it was a useless mod, as the key still needed to be used.

[some_other_dave]

Originally Posted by metromizer

Back to the original posters question/idea: I could see some merit in overall FE if a 'part time' system were employed, on demand supercharging'.

How about a belt-driven supercharger with something like an AC clutch on the pulley? I'm remembering the first "Mad Max" movie... If the draw from the belt and pulley when it was not engaged was low enough, it could serve as an on-demand system.

-soD