Ready to get flamed... Electric supercharger?

[Victor Meldrew]

Logic dictates that the bolt on electric supercharger has to be pants or all the manufacturers would be fitting them on there cars...

But if you could get one that gave enough flow to give a possitive improvement...

1. The inlet ducting and thottle body housing has to be airtight and able to contain pressure up to a point, or it would let in dust..
2. The ECU has a wide band lambda fitted and the fueling is self correcting up to a point..
3. There is loads of space now in the boot.
4. My mind works in mysterious ways.
5. They aint that expensive.
6. Supercharging is permitted in class A8.
7. If you never ask....

[Mikie711]

You must be a home coz you've obviously been on the piss!!!!!!.

You have to be able to regulate the air flow relative to engine speed. Not sure how you would do that with out some fairly elaborate electronic control. Motor would end up being a fair size to handle the compression of the required air flow especially at high engine rpm that and it would have to be 12V so you would need a much larger alternator to handle thwe current draw a large electric motor would draw.

Other than that and a few hundred other problems you'll have crack it...........go for it and let us know how you get on

[Victor Meldrew]

You must be a home coz you've obviously been on the piss!!!!!!.

You have to be able to regulate the air flow relative to engine speed. Not sure how you would do that with out some fairly elaborate electronic control. Motor would end up being a fair size to handle the compression of the required air flow especially at high engine rpm that and it would have to be 12V so you would need a much larger alternator to handle thwe current draw a large electric motor would draw.

Other than that and a few hundred other problems you'll have crack it...........go for it and let us know how you get on

Not at home, not pissed, just bored out of my tits...

[Victor Meldrew]

Motor would end up being a fair size to handle the compression of the required air flow especially at high engine rpm that and it would have to be 12V so you would need a much larger alternator to handle thwe current draw a large electric motor would draw.

I have no idea what the cf/min of the engine is at the moment, but in theory... all I need is a fan that can give a higher flow than what the engine pulls at peak flow to give some increase in pressure in the inlet manifiold. I have found a fan that flows 1000CFM and pulls 30amp.

You have to be able to regulate the air flow relative to engine speed.

Why? The desired end result is correct combustion, the wide band lambda feedback should still correct the fueling to give you this regardless of air flow and engine speed

[robin]

You have to have some way to work out how much air got pushed into the cylinder - you need to make sure that you don't push in more air than can safely be compressed. At high RPM that's easy - the flow into the cylinder is heavily restricted by the inlet valve duration. At low RPM, that's harder - the system is normally self limiting - it's designed safe at atmospheric pressure - but not at much more than that.

With a turbo, there isn't much problem - it'll not produce much boost below 3,000 RPM anyway.

With a mechanical supercharger, it'll produce boost across the rev range, but because it's syncronised to the engine rotation, the boost at low RPM is limited.

With an electric supercharger, you need to back the fan speed off at lower RPM, turbo-stylee.

Now assuming you have a suitable feedback mechanism to match fan speed to engine speed, you then need a mechanism to work out (or predict) how much air has actually entered the cylinder, revolution by revolution.

You also need to work out what to do with the pressure when the throttle is closed ...

All of this is easy from an electronics perspective; but you need a fan that can produce an extra 0.5 bar or so at 6,000 L/min (which is, I think, 200-ish cfm).

You need to look at your fan specs, but most ordinary fans really struggle to create significant pressure (they're good for shifting huge volumes, but not at pressure).

Cheers,
Robin

[BiggestNizzy]

I have seen these they are possible but they cannot be described as "fans" and are not cheap, most electirc superchargers are scams but they do exist, the one I saw had at least half a dozens motors attached to what looked like conventional looking super charger.

what about a ramair scoop, it won't do that much to be honest but will look cool.

[Victor Meldrew]

So technically its possible, but in reality not worth the bother..

[robin]

Well, it depends what you think the hard part is ... I think that electric superchargers are possible - the sort of power they can get out of KERS shows you that small form factor motors with the required power output do exist, but they're probably still a lot more expensive than a mechanical supercharger.

In 10 years I would guess that (assuming we're still allowed to burn hydrocarbons) electric superchargers might well feature on small form factor high efficiency engines (rather than use hybrids in the Prius/Lexus way). The engines would have very small capacities - at n/a levels enough to drive around grid-locked town; they would use dynamic valve trains to allow the engine to spin over without compressing (turn off cylinders, etc). Then when you hit somewhere that more power is required, the supercharger can come into play and get you up to 2-3x the capacity, effectively (also, the supercharger can replace the starter motor - blow started engine, anybody .

The conversion from mechanical->electric->mechanical energy is going to be very inefficient no matter how you look at it - so the technology would have to be very sophisticated in order to yield a net improvement in efficiency.

Where outright performance is the way ahead, I would guess that mechanical superchargers/turbo chargers tuned to the power delivery of the engine are likely to yield the best results for some time to come.

Cheers,
Robin

[woody]

What you want John is a steam turbine; use the heat from the exhaust to generate steam to drive a turbine that will drive a compressor.

[Victor Meldrew]

What you want John is a steam turbine; use the heat from the exhaust to generate steam to drive a turbine that will drive a compressor.

The amount of times I've seen a K series with steam blowing out of it you could be right.

[Rich H]

Nah, water injection with the fuel, at high temps it turns to steam giving massive expansion and higher temps.

3 phase motors are super efficient (95%+) but as robin says it's going to be the fan that is the problem.
My RC boat motor will sink 100A at 6V or so but it gets fecking hot inside a minute, so it's water cooled! Also it only runs for 3 mins or so.
You can run them on less voltage or load or revs to get higher efficiencies. They spin up to stupid revs too.

Problem will always be the lekky, you need several bhp:
1kW=1.3Bhp
1kW @ 13V=77A...
13bhp = 770A...

[woody]

3 phase motors are super efficient (95%+) but as robin says it's going to be the fan that is the problem.

But it's not a fan that you need; it's a compressor.

[Rich H]

What a bilge fan won't work?!?!

[BiggestNizzy]

What a bilge fan won't work?!?!

Did you see that website too ?


http://www.ecycle.com/supercharger.html

http://www.turbominis.co.uk/forums/inde ... &tid=11130

[Victor Meldrew]

What a bilge fan won't work?!?!

Did you see that website too ?

Must have missed the link...