Electric Turbocharger

[sierra]

Subaru were talking about using the heat from the exhaust to generate electricity not the pressure and momentum from the exhaust that turbos utilise.
There may well be more energy in the exhaust heat which is currently only a problem not a benefit.
My question is how will they convert heat into electricity and the only solution I can think of is to use the fuel cell principle.
You have to wonder if other waste heat, at much lower temperatures, from the cooling systems could also be used instead of being dumped to atmosphere??

So much for that idea. I thought they used heat from the fuel to generate electricity. Should have looked it up instead of relying on assumptions!

Maybe a modern version of the heat pump?

[solma]

@neutron256

KERS can be the same thing as an hybride cars per definition(Kinetics energy recovery system), my point is mostly in the technology use in actual "KERS" system, mostly use it as short burst of energy(that's the difference with "hybrid" car, as they are design for fuel economy/long term usage of recovered energy).

As you stated, Porsche, Ferrari use it, that prove my point, its for race/high performance application with a specific usage. The fact is that technology have been develop for political reason, gas engine pollute, high performance car had bad reputation with green people, meaning bad image for racecar and the industry=less money.

[solma]

Originally Posted by sierra

Subaru were talking about using the heat from the exhaust to generate electricity not the pressure and momentum from the exhaust that turbos utilise.
There may well be more energy in the exhaust heat which is currently only a problem not a benefit.
My question is how will they convert heat into electricity and the only solution I can think of is to use the fuel cell principle.
You have to wonder if other waste heat, at much lower temperatures, from the cooling systems could also be used instead of being dumped to atmosphere??

So much for that idea. I thought they used heat from the fuel to generate electricity. Should have looked it up instead of relying on assumptions!

Maybe a modern version of the heat pump?

They could use that kind of semiconductor http://www.pcbfacile.com/media/DT12-8_a.pdf, the cost is high and life short. Again alot of way of doing thing.

[Frostyman]

Originally Posted by Huehuecoyotl

Call me ginea pig..

Now now, gem, I know I have told you before, it's Guinea. lol

[ptuning]

Unfortunately, this concept is currently not be feasible, given the off-the-shelf components that are currently available to us.

We'll assume that a geared SC or TC are one and the same here. A typical supercharger that produces even a few psi of boost will likely consume about 20hp or so to run.

For the power levels that the current SC guys are trying to achieve, you're probably looking at closer to 40-50hp to run the SC.

A typical automotive alternator outputs around 90-120amps or so and a high output (audio guys use) unit may crank out upwards of 200 amps.

One HP equates to 746 watts. In order to achieve 20 hp, you'd need 14,920 watts of power. Given a typical alternator output of 14.4 volts and 200 amps, you'd still only see 2,880 watts of continuous power. You'd need 6-200amps alternators in order to drive the SC constantly under load, with just enough left over to run the car's electrical system.

While it's possible to have the alternator charge a set of say, very expensive lithium ion batteries... the extra weight, expense, and complexity would not make it a very viable option and you'd still not be able to use it at will.

Maybe if the automotive world adapted a 96 or even 120 volt system, this idea would actually be somewhat feasible.

Tuning would be interesting too, unless you had a very expensive motor controller or an elaborate bleed off system, otherwise you'd have a lot of boost down low when the SC switches on and very little boost up top.

This is always an interesting topic of discussion. Feel free to correct the math if it's off. If anyone wanted to try it out, check out this link, but think mini shot of nitrous at a very high price.

http://www.turbomagazine.com/tech/04.../photo_02.html

[neutron256]

Originally Posted by solma

@neutron256

KERS can be the same thing as an hybride cars per definition(Kinetics energy recovery system), my point is mostly in the technology use in actual "KERS" system, mostly use it as short burst of energy(that's the difference with "hybrid" car, as they are design for fuel economy/long term usage of recovered energy).

As you stated, Porsche, Ferrari use it, that prove my point, its for race/high performance application with a specific usage. The fact is that technology have been develop for political reason, gas engine pollute, high performance car had bad reputation with green people, meaning bad image for racecar and the industry=less money.

Porsche and Ferrari use KERS because they have a lot of experience with it from the racing world. There are plenty of non-supercar manufacturers developing it. Yes it is best for a short burst of speed, like getting the car moving again after coming to a stop which is when engine output is at its least efficient. It has a ways to go before its ready for most production cars, but I have little doubt it will become as common as electric hybrids soon.

[jamesm]

It's far more practical to use the electric motor to assist the engine at low speeds than it is to have it try and compress the intake charge. Either way you'll need a bunch of lipos and a fancy speed controller, so may as well just make it a hybrid and not worry about packaging constraints and lost energy in the electric 'turbo'.

[Shankenstein]

Originally Posted by ptuning

We'll assume that a geared SC or TC are one and the same here. A typical supercharger that produces even a few psi of boost will likely consume about 20hp or so to run.

For the power levels that the current SC guys are trying to achieve, you're probably looking at closer to 40-50hp to run the SC.

A typical automotive alternator outputs around 90-120amps or so and a high output (audio guys use) unit may crank out upwards of 200 amps.

This is precisely what I was hoping to find out. A light-duty supercharger uses 20 HP to generate 60 hp.

20 hp = 15 kW. At 12V, that's a 1250 A alternator. At 90V (a convenient setup for DC motors), that's a 167 A alternator, which is much more feasible. Lots of windings and more power to dissipate through the rectifiers, but it's possible.

If they used a bank of ultracaps to stabilize the system and store recovered energy... I could see 2 of these installed across the rear axle: Maxwell 75V bank

That's 188F of capacitance at 75V. 1/2 * C * V^2 = 529 kJ. Let's say you're running the 1/4 mi and want free flowing exhaust, so the supercharger is running 100% off KERS. You get 3 full runs. Running with the exhaust turbine on would probably not drain the pack at all, but the back pressure would hurt power levels.

Power to weight ratio. Batteries add 110 lbs. turbine/supercharger/motors/wires, etc. might add 90 lbs. 160 hp / 2600 lbs vs 220 hp / 2800 lbs. That's a 25% increase in power-weight ratio using only wasted energy from the engine.

Just sayin', the technology may not be there yet, but that doesn't make it impossible or even a bad idea.

[XPR Small Block]

really? you guys believe this crap works?

[Shankenstein]

I believe that air compresssors compress air.

I believe that generators generate electricity.

I believe that batteries and caps store electricity.

Whether it can be done efficiently or effectively, is what the discussion is about. As an R&D engineer, I see dissenting opinions and welcome the perspective they can provide... but don't be surprised if non-contributing discussion is ignored. Remember the first thing I wrote:

Originally Posted by Shankenstein

Purely hypothetical discussion ahead. Turn back all ye who may say "this is stupid!"

This was actually talking to you.

[carbonBLUE]

Originally Posted by Calum

There's been a lot talk about this from BMW aswell, though I haven't seen anything in a while. One of the biggest problems was moving the electrical power around at the current 12 volt automotive standard. A few OEM's were lobbying to move to 48 volt systems, or even 48 volt partial systems. It seemed from what I read that the infrastructure became a lot more manageable at the voltage.

Originally Posted by Shankenstein

Purely hypothetical discussion ahead. Turn back all ye who may say "this is stupid!"

If an exhaust turbine and wastegate are installed on our engine, what is an example of turbine shaft torque and speed? How much energy (temperature and pressure above atmospheric) can be used for regeneration?

Two options for generating power:
- gear down heavily and employ a high-output alternator
- run a DC electric motor in reverse

Similarly, can an intake compressor be run from a DC motor? Not talking the tiny electric superchargers on eBay... I'm talking voltage step-up + 1/2 hp dc motor + centrifugal/twin screw compressor (a la Vortech).

The idea has been tossed around by Subaru: HERE for the next WRX.

I'm just trying to wrap my head around how challenging this would be.

Potential issues:
- Sizing a battery/capacitor bank
- Management of alternator clutching
- Management of battery/capacitor bank discharge rate
- Integrated BOV with instant pressure relief (compressor motor braking)
- Cost and hardware weight would be high.

Potential awesome:
- No lag, as long as you've got battery power.
- Boost pressure can be closely controlled via dedicated feedback controller.
- The system can be switched to "ECO" mode for regenerating energy to supplement the alternator (would require an isolator for starting battery).
- The system can be switched off completely.
- Combination of the above. ECO mode during low load, low rpm driving. Instantly switch on above X% load.

Comments? Discussion?

or you could go with a heavy flywheel, bolt a supercharger to the flywheel just as the starter is, then you dont have to worry about belts!



or strap an alternator to the flywheel in the same fashion, vary voltage depending on how much power you need to run the electric supercharger. This way you can create instant boost at any rpm. this means you can run any psi at any given rpm

[sierra]

Originally Posted by carbonBLUE

or strap an alternator to the flywheel in the same fashion, vary voltage depending on how much power you need to run the electric supercharger. This way you can create instant boost at any rpm. this means you can run any psi at any given rpm

Are we assuming that using the electrical energy stored to produce boost will produce more power than simply using it to drive a brushless electric motor?
I find that very hard to believe.

[spyingwind]

Originally Posted by sierra

Are we assuming that using the electrical energy stored to produce boost will produce more power than simply using it to drive a brushless electric motor?
I find that very hard to believe.

About the best helper in looking for the right motor Wikipidia - Comparison by major categories.

It doesn't really matter what motor is chosen, because it will come down to the part that generates the power for the motor. It has to have a high enough efficiency and can put out enough power to run our motor.

Maybe a modified SC or TC?

Oh also, this was a good read. Wikipedia -Turbocharger - Boost threshold

[mad_sb]

Hmm, so it seems what you need is a small petrol or diesel engine to run the electrical generator, a system for storing the electricity, and a dc motor that can introduce power into the drive train... oh wait.. that's a hybrid

Lol, anyway, this is a good topic. Thinking outside of the box is always good even if it does not produce any viable results in that moment... it can lead to other thoughts and other ideas as well as eliminating the ones with no potential.

Are there any fuel cell technologies that could produce enough power to drive a reasonable sized ESC?

Potential Energy (gasoline) -> Mechanical energy (combustion) - > Electrical Energy (generator) -> Potential Energy (storage system) -> Electrical Energy -> Mechanical Energy (SC DC Motor) -> Additional Potential Energy (compressed air)... seems like to many state changes to be efficient.. each step has losses associated with it.