CPT Electric Superchargers

[lamb jiblets]

Anyone seen this weeks Auto car mag. Thers an artical on electric superchargers,
They say it will improve mid range 45-65mph by 40%, with the ever increasing tech in electrc motors (switched reluctance drive bushless motors) do we now think this will be a worthwile bolt on when avalible? or are we all sceptical of such things.

[shangani]

Two words:

Snake Oil

Think about a supercharger and how much parasitic loss they have. What sort of electric motor would you need to provide the same effect?

[bencollins]

Ive always wondered about these.
"In my head" they work, because of the thousands of litres of air going through the engine every minute. Im curious and will b reading thee indie analysis. thanks for the tip off.

[dilbert]

There is no reason why they shouldn't work in general. I have also seen people trying to peddle fans like those you find inside a computer case, which are just not going to do the business.

[Scuffers]

bencollins said:

Ive always wondered about these.
"In my head" they work, because of the thousands of litres of air going through the engine every minute. Im curious and will b reading thee indie analysis. thanks for the tip off.

lol!

• IF* you can shift 500CFM at 0.5+ bar then yes, it will work, however, you might just want to look at the sort of power required to do this...

[dilbert]

shangani said:

Two words:

Snake Oil

Think about a supercharger and how much parasitic loss they have. What sort of electric motor would you need to provide the same effect?

It's probably worth bearing in mind that no new military ship smaller than a cruiser is likely to have anything but electric drive from pretty much a couple of years ago. There have been some advances in semiconductors that make it possible. The motor is not the problem. It's controlling the motor that is the problem.

I'm not really sure what the advantage of using a motor is, beyond say the packaging of the engine, but a good old belt would seem the simplest approach. I wouldn't know if there is a compromise to be made with a belt drive system, but certainly a variable speed electric drive could give total control of the compressor speed, and complete independence from the traditional crank/compressor pulley ratio.

I would imagine that a large chunk of the 20hp that you need to drive the compressor, is due to transmission losses, and the potential crank~compressor ratio compromise. These are simply not present with an electric drive. Certainly 10hp in a suitably sized package is not beyond the bounds.

Edited by dilbert on Sunday 13th April 23:34

[subaqua]

LOL... isn't it reputed to be the case that the maclaren mercedes SLR needs over 120bhp just to run the blower - that'll be the K from your standard S1 operating at max output.

[dilbert]

subaqua said:

LOL... isn't it reputed to be the case that the maclaren mercedes SLR needs over 120bhp just to run the blower - that'll be the K from your standard S1 operating at max output.

Your numbers sound dodgey to me, but what do I know!

I'd also say that most cars aren't Mercedes McLarens. The majority are about 1800cc, and with a compressor like I described, you're looking at 200bhp output with the compressor. I wouldn't be at all surprised if we see more of the electric supercharger myself.

With the sort of control you get from the electric drive, you can combine good performance and fuel economy, at remarkably low cost. That's always been a good recipe for sales.

Edited by dilbert on Sunday 13th April 23:41

[GreenV8S]

I see the electric supercharger more likely to be a 'fill in' or anti-lag device for a turbo. And having nothing at all in common with little 'supercharger' fans that the scallywags are selling on ebay.

[dilbert]

GreenV8S said:

I see the electric supercharger more likely to be a 'fill in' or anti-lag device for a turbo. And having nothing at all in common with little 'supercharger' fans that the scallywags are selling on ebay.

Amen to that!

[Esprit]

Interesting video on youtube of someone doing dyno runs with/without a common electric garden leafblower hooked up to their intake.... The motor in one of those is a couple of kilowatts at the most.

Seemed to yield actual noticeable results. Certainly not the sort of thing you can run high boost on for mega horsepower, but no reason why an efficiently designed system shouldn't be able to provide a good, economical boost in power and torque.

[Poledriver]

Esprit said:

Interesting video on youtube of someone doing dyno runs with/without a common electric garden leafblower hooked up to their intake.... The motor in one of those is a couple of kilowatts at the most.

Seemed to yield actual noticeable results. Certainly not the sort of thing you can run high boost on for mega horsepower, but no reason why an efficiently designed system shouldn't be able to provide a good, economical boost in power and torque.

Link?

[Esprit]

Poledriver said:

Esprit said:

Interesting video on youtube of someone doing dyno runs with/without a common electric garden leafblower hooked up to their intake.... The motor in one of those is a couple of kilowatts at the most.

Seemed to yield actual noticeable results. Certainly not the sort of thing you can run high boost on for mega horsepower, but no reason why an efficiently designed system shouldn't be able to provide a good, economical boost in power and torque.

Link?

http://youtube.com/watch?v=dyR0U_fYtwY

That's one of them, there was a slightly better one floating around too on an older car. using a bigger blower

[dilbert]

If you're interested in the possible motor technologies, cop a look at this for some ideas.

http://www.automation.siemens.com/ld/ac-motor-high/html_76/asyn-kaefig/h-compact/h-compact.html 

I mean these are big motors, but for their output, they're physically quite small. Scale it down and you're on to an application winner. Water cooled, perhaps 1.5KV, not bad.....

For the inverter, perhaps a nice place to start would be with General Atomics;

http://www.power-inverters.net/ 

I wonder how much carbon offsetting that's worth??!!

Edited by dilbert on Monday 14th April 02:25

[Silent1]

dilbert said:

GreenV8S said:

I see the electric supercharger more likely to be a 'fill in' or anti-lag device for a turbo. And having nothing at all in common with little 'supercharger' fans that the scallywags are selling on ebay.

Amen to that!

Like a Pious, but with the batteries performing some sort of lag-assist for a big turbo

[Scuffers]

GreenV8S said:

I see the electric supercharger more likely to be a 'fill in' or anti-lag device for a turbo. And having nothing at all in common with little 'supercharger' fans that the scallywags are selling on ebay.

exactly..

consider that the Eaton M62 we use on the Honda's is pulling the best part of 40Bhp to drive it....that's 30KW....

now, a simple belt is way more effecent than an alternator/battery/invertor/electric motor/etc...

there are elec chargers used in snow-mobile racing, but they only run for 5-6 sec's and pull 4x25A into a 1,000cc engine.

[kambites]

Scuffers said:

now, a simple belt is way more effecent than an alternator/battery/invertor/electric motor/etc...

Not by as much as you'd think.

It's more efficient to use a petrol engine to drive a pair of electric motors via a generator than to have a gearbox and diff making a physical connection. A typical transmission is, what, 80% efficient (bhp at the wheels vs bhp at the flywheel). An electrical drive system can easily be 90% efficient as long as you're not having to store the energy anywhere.

The problem with an electric supercharger is that you'd need an alternator and motor combination capable of producing about 40bhp which would end up being far bigger and heavier than a simple belt driven system. It would have its advantages though...

[dilbert]

kambites said:

Scuffers said:

now, a simple belt is way more effecent than an alternator/battery/invertor/electric motor/etc...

Not by as much as you'd think.

It's more efficient to use a petrol engine to drive a pair of electric motors via a generator than to have a gearbox and diff making a physical connection. A typical transmission is, what, 80% efficient (bhp at the wheels vs bhp at the flywheel). An electrical drive system can easily be 90% efficient as long as you're not having to store the energy anywhere.

The problem with an electric supercharger is that you'd need an alternator and motor combination capable of producing about 40bhp which would end up being far bigger and heavier than a simple belt driven system. It would have its advantages though...

That's just it. We're all used to the power/proportions if common or garden motors that run off anything from 12V up to perhaps 240.

If you crank the voltage up to beyond a kilovot, motors become fantastic things, small, seriously powerful. Obviously the motor has to be designed to suit, but the higher the voltage, the better. People ought to have some feeling for that concept in respect of the battery power drills that you get. Remember the 7V jobbies, how they've moved on now that they are as much as 18V.

The other thing to think about it that most cars have all of the facilities for water cooling. You can apply that to electic motors too.

[Fume Troll]

Certainly not snake oil, electically driven superchargers have lots of interesting potential for increasing overall system efficiency. No, the electric system won't be as mechanically efficient as a belt when viewed simply, but the ability to turn it up/down/off and run it off stored power is very interesting.

Cheers,

FT.

[LivinLaVidaLotus]

As someone has already said, the higher the voltage, the more efficient the motor is at doing any given item of work. I'm sure most people must have done the experiment in their school days - have a motor connected to a pulley, lift a weight from the floor to a set height - measure how many joules are used at different voltages.