electric super chargers

[Helicopter]

Agreed, we can discuss volumetric efficiency in great lengths, but even 80% of 235 litres/sec = 228 litres/sec of air to give you 1lb boost at 6000 rpm. Even at 3000 rpm you need 114 litres/sec of flow with pressure to get a wopping 1lb of boost. Using a propeller, its easy to generate air flow, but pressure cannot not be maintained regardless how fast the propeller is spinning.

So I will say it here again, it is not possible to flow this amount of air and maintain pressure using a single stage propeller [which is what this electric 'supercharger' device is]. In fact this design is no more than a ducted fan assembly as used in model RC aircraft.

We can debate this all day, but I work with real jet engines. To produce air flow and pressure we need either complex multiple axial stages or alternatively using a single centrifugal compressor. [Why do I have to repeat this?]

This little cheap device will do nothing but drag heaps of power from the battery and as a bonus act as an neat air flow obstruction at higher rpm's.

Remember electric motors have been around for 100 years, yet no one has managed to make a 'practical' supercharger [for medium to large capacity engines] without resorting to an electric motor the size of a bucket seat and a multitude of 12V batteries in the boot. I would hope common sense would prevail, but don't let me stop anyone who wants to throw away some money.
Good luck.

 

[EvoVIIIJDM]

this is what we are talking about?

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[Cursed CX8]

lets just buy one and see if it works, hell lets buy 2, the cheap one at $99 and the $300 one for holdens on ebay. lol

 

[commsirac]

Agreed, we can discuss volumetric efficiency in great lengths, but even 80% of 235 litres/sec = 228 litres/sec of air to give you 1lb boost at 6000 rpm. Even at 3000 rpm you need 114 litres/sec of flow with pressure to get a wopping 1lb of boost. Using a propeller, its easy to generate air flow, but pressure cannot not be maintained regardless how fast the propeller is spinning.

So I will say it here again, it is not possible to flow this amount of air and maintain pressure using a single stage propeller [which is what this electric 'supercharger' device is]. In fact this design is no more than a ducted fan assembly as used in model RC aircraft.

We can debate this all day, but I work with real jet engines. To produce air flow and pressure we need either complex multiple axial stages or alternatively using a single centrifugal compressor. [Why do I have to repeat this?]

This little cheap device will do nothing but drag heaps of power from the battery and as a bonus act as an neat air flow obstruction at higher rpm's.

Remember electric motors have been around for 100 years, yet no one has managed to make a 'practical' supercharger [for medium to large capacity engines] without resorting to an electric motor the size of a bucket seat and a multitude of 12V batteries in the boot. I would hope common sense would prevail, but don't let me stop anyone who wants to throw away some money.
Good luck.

Why say it again when you have already said it.......I for one wasnt disagreeing that the device based on simple physics as we understand it couldnt deliver the claims.
I accept your point that (80% of a lot, is still a lot), however,(20% error due to neglecting ve is also significant) I did clarify your calculations as there seemed to be some distress from others as to their accuracy and you welcomed being corrected here!

.
The air volumes are correct as are my calculations based on the 5 litre engine, so offence taken Andrew246, and always happy to be corrected if wrong.!!

But now you are unhappy?
I didnt get involved into the effect of the volume of vaporised fuel either, as it is unclear whether we are talking specifically about the VR/S, direct injection, manifold injection or even just petrol powered cars in general.

 

[Helicopter]

Who's unhappy? I'm always happy.......I think!

I guess the main aim of my ramblings was to first concure with what most people already stated, and secondly with the addition of some technical emphasis to the fact
it was impossible for this device to perform the way it was claimed, as it appeared some members did have a few doubts.
I don't like it when people are fooled into spending hard earned money by these ebay sellers, that's all.

 

[Cheap6]

This thread has got rather interesting.

There's not too much that is new in automotive technology. I have a magazine article somewhere from the '80's about a turbo. manufacture (KKK I think) looking at using an electric motor designed for propelling torpedos (as in Naval explosive devices) to drive a centrifugal supercharger.

Apparently one issue (and the reason for using the torpedo motor) was the rapid response time required to prevent unacceptable throttle lag, so it appears that it's not just the ability to pump air at the rate required that is important but also the ability to accelerate the compressor to a boost producing speed in an acceptable timespan.

i found this site should have a look it produces 5psi
Thomas Knight Turbo Electric Supercharger - Tech Review - Turbo Magazine

HOWEVER there is one type of electric supercharger that does work. these are the ones that have like 3 huge batteries of their own, and the s/c only engages on full throttle creating good boost for about 15 seconds. still don't see the point though...

Not suggesting the device sounds a good idea, though if you use the power comes from idle batteries that can provide a couple of kW for the length of a drag, rather than taking it off the motor, then it may have merit.

The ESC-400 does look interesting, given that it would appear to provide what is really required for a road vehicle or a vehicle used for drag racing. The use of the positive displacement type S/C may remove some of the compressor kinetic energy requirement ie. power absorbed accelerating the compressor.

Conceptually, it's not vastly different from a parallel hybrid like Prius or Honda's Integrated Motor Assist (IMA) in that the electric power is stored slowly and released only when high power is demanded. It's just that the available electrical power is being used in a different way.

(It is a general misconception that the only gain from parallel ICE-electric hybrids is from the kinetic energy reclaimed with regenerative braking. That is only part of the economy gains seen. Much is from the ability to more closely match the ICE to the average power requirement rather than the peak requirement. One article I read (with a petrol electric parallel hybrid - again from the '80's) found that the average power used was 6kW, with the peak 40kw for a 1500kg car, in urban driving. This is also the reason why the gain with Diesel-electric hybrids is not so great; they are already quite efficient at part load. It's also why those people fitting extra batteries to Prius' - and adding the ability to plug into mains power - don't get the concept. They are really wanting a pure electric vehicle rather than a hybrid.)

my air compressor tank is capable of 150psi, maybe i should carry it in the boot and pipe it into the intake.

OPEN VALVE=40PSI boost!!!

I know that comment is intended as facetious but it's not completely out there either. While it would be difficult to find volume enough in a car to store sufficient air at normal (industrial type - ~100-150psi) compressor pressures (I've done the numbers ), the same concept using much higher storage pressures (like diving cylinder pressures) has been considered and developed to the stage of working prototypes. This occurred 40 years ago (I said there's not much new in automotive technology).

One system used an air ejector - converting the pressure energy in the cylinder to kinetic energy in a nozzle, entraining ambient air in the flow, then converting the combined flow back to (lower) pressure energy in a diffuser. The second system used a second inlet valve (and cam to open it) for each cylinder which admitted the compressed air directly when required. These systems have the advantage of perfect intercooling of the component of the air being inducted that is precompressed. This is because the duty cycle is low enough to allow the air in the tank to cool to nearly ambient before it is introduced into the engine.

In each system the cylinder pressure was restored using an engine driven compressor operating when engine power demand was lower than peak.

The aim was to allow a downsized engine as per extant petrol-electric hybrids.

It's also interesting to see that Zex, a manufacturer of nitrous equipment, has a device claimed to exploit the air ejector principle.

https://shop.sae.org/technical/papers/670109

https://shop.sae.org/technical/papers/920843

Large Steam System Condensers - Heat Exchanger* -* Engineers Edge

http://www.graham-mfg.com/downloads/225.pdf

Zex.com - Nitrous Performance (search "air ejector")

 

[jd67]

they are a joke

 

[jd67]

what a waste of money