RE: Electric Superchargers On The Way

[RichardR]

The Black Flash said:

Up until now, the wisdom has been that the power required to drive an SC means that it's been more efficient to use a belt directly to the SC, rather than using it to drive the alternator which in turn drives the SC.
Be interesting to know how they've got around that. The advantage of being able to switch it on or off are obvious though.

The article states that it is specifically designed to be used in conjunction with a turbo, so it's presumably an evolution of the current super/turbocharger combinations but with the electric operation allowing an instant increase in compression at engine speeds where even a convential supercharger would not be spinning fast enough to generate any significant pressure.

[jambon t2]

I may of missed it but the article does not make any claims about top end power. I thought the intention was to improve drivability of downsized engines . i.e. improve the torque in the low (sub 3000) range. At these speeds turbo/super chargers dont work - this electric blower can still work as it would use power stored in the battery ? also less air required at these lower rpm so it is easier for it to acheive a useful result. I think the article says that it complements turbo/super charger.

[the Fantom]

JonRB said:

The Black Flash said:

The advantage of being able to switch it on or off are obvious though.

preferably with a switch on the gear-lever Max Max style.

The ebay ones are triggered by a switch which is operated when the accelerator pedal is fully depressed - makes sense as you only want the extra boost when at full throttle. I would expect the one being discussed above to be ECU controlled.

[mikea4tdi]

Don't forget the unit will be for a small engine 1 to 1.4 ltrs so you shouldn't compare it against the turbo size for a 2 to 3 ltrs car.
It should give the low down torque required and can be turned on or off or regulate the boost as needed by the driver also maximising effeciency when cruising at 60 etc.

Regen braking requires a lot more hardware and hence is expensive, note f1 KERS systems is basically that a regen device for a standard engined vehicle.

[red_slr]

Anyone who is involved with RC models will know that there are some fairly decent flow rates to be had with big brushless motors and ducted fans. 1Kg of thrust is no problem, and IIRC quite a few people have managed 2kg of thrust from larger fans.

Also, there are some massive RC helicopters running on motors now - only 3 years ago there was no chance you could get these big models flying on anything other than gas motors.

http://www.icare-rc.com/plettenberg_predator.htm

[dwilkie]

Good point, the T25 is as you say sized for a 2 Litre. It's kinda not what I mean though, the point I was trying to get across was the 120mm fans in our servers are rated at 115cfm, and are quite large. Surely a fan that small would struggle to move any reasonable amount of air?

It's not my area of expertise, but dont' mistake this for trolling, i am actually genuinely interested

[gareth_r]

There has been a working electric supercharger for a while, but it needs a lot more power than a PC cooling fan
http://www.boosthead.com/home.php

The Knight electric supercharger takes up to 1200 amps at 12 volts - almost 20 bhp ... good luck with producing that much power with anything you buy from eBay......

Edited by gareth_r on Wednesday 23 September 14:17

[dwilkie]

That one you linked though draws a sizable voltage and a huge current for something in a car...

[gareth_r]

dwilkie said:

That one you linked though draws a sizable voltage and a huge current for something in a car...

Precisely. Doesn't the Merc SLR use something like 100bhp to drive its supercharger at peak power?

Edited by gareth_r on Wednesday 23 September 14:19

[mrmr96]

andyroo said:

I may have missed something, but wouldn't the power needed to operate this thing drain a similar amount from the engine via, presumably, a larger alternator?

You're quite right in so far as there will be a parasitic effect on the engine via extra current draw on the alternator. But these things will allow more air to be pumped into the engine, which allows more fuel to be burnt per revolution, increasing torque and therefore power. This is not a free energy machine, it's a way to burn more petrol and the extra power will more than offset the parasitic effect of running the charger.

[barks]

So this is basically the same as the VW turbo supercharged units but rather than getting its power from being driven mechanically the supercharger gets it power by the engine driving an alternator and then supplying a current to drive an electric motor which in turn drives the supercharger.

So why not ditch the turbocharger and install an exhaust driven turbine alternator? That way you could reduce load on the belt driven alternator as the engine speed builds up. Assuming your electric supercharger is up to the task of providing the necessary boost at high RPMS. This would also allow you to control boost without the use of a wastegate as you can control turbine speed directly .

Edited by barks on Wednesday 23 September 14:37

Edited by barks on Wednesday 23 September 14:41

[Playerhater]

This isnt a new idea! I fitted my girlfriends hair dryer motor to the exhaust of my mates 1 ltr micra, and through a switch not unlike a Ferrari's on the wheel in the third setting it gave a healthy gain 85bhp atw! Currently we are trying to use her GHDs as a alternative to the troublesome coil pack in my S3.

[ctallchris]

Stig said:

andyroo said:

I may have missed something, but wouldn't the power needed to operate this thing drain a similar amount from the engine via, presumably, a larger alternator?

Well spotted - and they were doing so well!

A standard supercharger will be spinning at a rate according to the engine speed. If it's controlled electrically you have more control. You probably would have to increase the alternator size but a standard alternator produces excess current which is wasted at high speeds (where the supercharger would need to be driven hard).

The extra draw on the alternator would definitely be less than mechanically driving the supercharger.

[Marf]

http://www.integralp.com/supergen.aspx

This looks quite promising too.

[jambon t2]

"One horsepower for rating electric motors is equal to 746 watts. "

so in SLR case that would be a 74.6KW electirc motor (100 bhp for SC)

which would be 6216 amps @ 12 volts ;-D

anybody know how to work out cable size for 6216 amps @ 12 v ?

Edited by jambon t2 on Wednesday 23 September 14:51

[alock]

Article said said:

...delivered in less than a second.

That lag belongs in the 80s

[crb]

alock said:

Article said said:

...delivered in less than a second.

That lag belongs in the 80s

I think they mean 1 sec from ignition, not foot down......................boost.

[Aerostar]

How can it classed as a supercharger, if it is not connected and driven by the engine? I presume the electricity is obtained by some sort of kinetic recovery system which is stored for use at some later time, or otherwise a alternator, fuel cell or battery?

[ctallchris]

Aerostar said:

How can it classed as a supercharger, if it is not connected and driven by the engine? I presume the electricity is obtained by some sort of kinetic recovery system which is stored for use at some later time, or otherwise a alternator, fuel cell or battery?

Supercharging an engine is just the act of forcing induction via a compressor. A turbocharger is a type of supercharger the "turbo" bit just comes from the turbovanes in the exhaust which drive the supercharger bit

http://en.wikipedia.org/wiki/Supercharging#Superch...

[barks]

crb said:

alock said:

Article said said:

...delivered in less than a second.

That lag belongs in the 80s

I think they mean 1 sec from ignition, not foot down......................boost.

No I think they mean from foot down. Remember though that this is at low engine RPM and is complemented by a typical mechanical turbocharger when the engine speed is higher. So at higher engine speed you will get whatever boost response your mechanical turbocharger gives. At lower speeds you have to wait a second for the electric motor to spin up the compressor, I think its this spin up time that they are quoting. A second really isnt a long time to wait for boost! It will give boost from engine idle as long as it can get enough electrical power to spin up the compressor.