Exhaust driven Alternator

[FormulaTwo]

Alright I have read about this. And i want to do it. Because i feel it can be done.

please remember
not an alternator
but a "wind generator"
useded to turn wind into electricity.

tried to change the post title****

I think a few of you have this confused.
In this case, the wind will be the EXHAUST flow.
On the models i have seen, they generate 8000watts, at 15mph of wind....

Now, im not sure how many RPMS it will be turning at 15mph, but it seems the turbo would spin a ton more. Which would most likely equal out to more power being generated.


A belt driven alternator in not efficient. This site has proven that.
For a performance car, a turbo is more efficient than a Supercharger, there is a big debate on this but regardless....

I want to make a way to charge my battery from my exhaust gas, instead of a belt, Removing all acc. belts from the engine.

A friend of mine has a t25 turbo from an eclipse sitting around..
I am thinking i can find a way to combine this with a wind generator


WIND GENERATOR like this....


Somehow combining the rod from the wind generator to the center section of the turbo exhaust turbine.

According to this website, the generator it will produce 8000watts.
Now i know watts, amps and volts all work out together but i do not actually understand them or their formulas.

http://www.survivalunlimited.com/windpower/pmasc.htm



Ideas......

- Use HF manifold (found on VX civics, HF crx's)
- Wind Generator (8000 watts)
- T25 turbo (Mitsubishi eclipse 95-99 models)
(break down turbo, Use "hot side")
- Make a new rod that will connect the hot side exhaust wheel to the wind generator)


Exhaust will flow down through manifold, into turbine housing. Spinning the wheel, which in turn will spin the Wind generator core.

I have everything i need to do it. I can weld etc....

My only problems are....

- A way to make a center section that will use bearings, INSTEAD of with an engine oil feed line.
- Finding a way to connect the generator shaft to the Turbo shaft and wheel.
- making it balanced.
- making it dependable
- finding a formula to figure out how many watts it will produce at certain engine rpms, and if it will be enough to charge the battery under normal highway driving etc...

If you guys can help me with this it would be appreciated.
Once again, I am not trying to TURBOcharge my car. Just replace the alternator with a new system.
I would draw up a picture but i do not have time right now. Maybe tomorrow
Help me out, we will make my car the guinea pig!

More pics,

[omgwtfbyobbq]

I'm thinking you'll need an oiling system because the heat from the exhaust will probably cook any bearing/grease combination. There's also the matter of what the heat will do to the generator, etc...
If you're really dead set on doing this you might want to run the turbo normally, and instead of going through an IC to the intake, have it go through an impellor that's connected to an alt. But even then, it's way complicated and you'd probably be better off running an extra battery and charging it while at home.

[Matt Timion]

I've been brainstorming this for a while now, but I don't have the knowhow. If you can get a working model, I am certain you can sell it to Honda enthusiasts.

[FormulaTwo]

The only reason I do not want to run oil lines etc... is because, im worried that when i remove the compressor housing and make a way to connect the rod. That there will be an oil leak. Causing Oil to spray freely, or into the o2 housing .


An article on the generator idea.
http://www.greencarcongress.com/2005..._exhaust_.html

Someone help me figure this out. I am determined to make this work!

[JanGeo]

yup rpm will stop you dead before you go any further . . . turbo 60,000-150,000 rpm . . . alternator 15,000 rpm max . . . what makes you think you can get turbo power out of an engine at low power throttle use also.

[onegammyleg]

Hi ALL

I rather like the redneck way instead



The funny thing about this picture , is that IT IS GENUINE

[onegammyleg]

But seriously , the whole idea of running an ALT from exhaust gasses is not a very good one.
As pointed out in other posts , exhaust gas flow would be too little to turn it at idle or light throttle and it is likely that you rwould need a gear box to reduce the rpm to the ALT.
But that would again make for low output at any normal driving speed at lite throttle.

Even IF it did mechanicaly work, th epower needed to turn the ALT is not free.
The 1 or 2 HP (?) needed to turn it (at full output) would be shown as a restriction on the exahaust.
I would guess that the motor would run worse with that setup than just running a conventional belt drive.

What you need is to get FREE power !!! (or almost free is good too)

How about , running an electric clutch on the ALT pully.
So that it only locks up and starts charging at idle or deceleration.
The clutch can be switched in or out with a simple vac pressure sensor., and the parts to do the clutch can be salvaged off a air con compressor.
CHEAP MOD

KaChing , almost free power

[DaX]

First problem - RPM's...as discussed above, but this can be overcome with gearing.

Second problem - Heat...I used to run a turbocharged Civic...the turbine housing temperatures were insane...preventing this heat from transferring into the generator is going to be very difficult.

Third problem - Torque...you'll need to determine the torque required to turn the alternator at full load through a range of RPM's (essentially dyno testing the alternator at full load). Then you'll need to see if the turbine can provide such torque at each RPM (whether you use gearing or not).

Not trying to slam the idea, just proposing some issues I see right off the bat.

[MetroMPG]

Originally Posted by theclencher

but then I thought, all that fooling around and expense to potentially save what?

On a 3-cyl Metro? About 10% FE increase @ 70 km/h (running off the battery):

Alternator v. no alternator

[Matt Timion]

Originally Posted by onegammyleg

But seriously , the whole idea of running an ALT from exhaust gasses is not a very good one.

I actually think it's a brilliant idea.

http://www.greencarcongress.com/2005..._exhaust_.html

http://66.102.7.104/search?q=cache:E...ient=firefox-a

[FormulaTwo]

please remember
not an alternator
but a "wind generator"
useded to turn wind into electricity.

I think a few of you have this confused.
In this case, the wind will be the EXHAUST flow.
On the models i have seen, they generate 8000watts, at 15mph of wind....

Now, im not sure how many RPMS it will be turning at 15mph, but it seems the turbo would spin a ton more. Which would most likely equal out to more power being generated.

[FormulaTwo]

Link to wind generator.

http://www.nrel.gov/wind/animation.html

Im wondering how many rpm, the exhaust turbine would flow at IDLE, and under 2500rpm....
This would be my operating range of engine RPM.
also,

the rpm issue could be fixed with the exhaust wheel. TO turn less rpm.

[omgwtfbyobbq]

As a concept I think it will definitely have it's day. Especially when paired with a low disp, twincharged gasoline engine that drives like a diesel since a turbo doesn't use all the energy from the exhaust all the time, and a supercharger is needed for more air/power at low rpm. But... It just seems like something that's not practically doable for the DIY'er. I think getting a few deep-cycle batteries and a solar charger is the ticket to the same savings in mpg w/o all the hassle.

[Kraig]

I think you also need to consider the rotating mass of the alternator versus the mass of the compressor side turbine of a turbocharger. I've rebuilt my turbo before and the impellers are relatively light. Not sure if the alternator would spool up worth a darn and would actually pose as an exhaust restriction (trying to accelerate the large mass of the armature) giving poor performance and efficiency. I would imagine you would build up alot of pressure in the exhaust manifold (a bad thing) causing the exhaust to actually back flow into the combustion chamber diluting the incoming air/fuel charge with less than desirable results. I think you would actually get worse FE. On a regular turbo setup it requires some power to actually run the turbo (nothing is free) but the performance gains significantly offset the slight loss. On your proposed setup you would just see the loss with no performance gain (perhaps a small efficiency gain). I doubt this small gain would overcome the effort required to get a heavy armature to spool up.

Just my 2 cents worth. I've driving turbo 4 cylinders since 1985 ....

[Kraig]

Another 2 cents worth. A turbo doesn't make boost unless there is a load on the engine (acceleration), when you're cruising along the impellers are just spinning and not creating boost. The only way you'd create enough exhaust energy to run an alternator would be under acceleration. You'd probably have to do alot of acceleration to keep your battery charged. Heck at cruising speeds you might not even have enough exhaust energy to spin the armature and all you'll have is a highly restrictive exhaust most of the time (an impeller spinning slower than the speed of the exhaust gases would be a restriction). I'm not trying to discourage some from trying this, but I don't the effort would be worth it personally.

[FormulaTwo]

Some people say it would spin too fast.
Some of you say it wouldnt spin enough to generate anything because of the friction.

I do not personally feel that restriction would cause exhaust to back up. Keep in mind these things are easily turned at 10mph. Ofcourse thats with a big enough fan blade to turn it.

But i think that with the right exhaust wheel, you could get the shaft to generate enough electricity at idle.

Here is a chart for wind generators and what they produce at each MPH.

http://www.greeleynet.com/~cmorrison/windcalc.html

[ZHangYang]

I have the similar idea, and some problems to deal with. 3 years have passed, and I wanna know whether your idea has come true.

[RoadWarrior]

Maybe he has realised that the mass of air hitting a 20ft diameter wind turbine at 15mph is hugely greater than that in the 2" cross section of exhaust pipe...

Which is the same as thinking you can pour a cup of water off the top of your apartment building to generate the same power as a large hydroelectric power station, because it's the same "head".

However, there should be a significant amount of recoverable energy, just have to start with something reasonable sized and work the efficiencies upwards.

[scho]

What if instead of connecting the shaft of the turbo directly to the input shaft of the generator, the turbo shaft was connected to a gear that drives a chain. That chain would drive a gear on the generator. This would allow the user to tune the gear ratio and it would also cause a mechanical separation to avoid heat soaking the generator. Perhaps a clever use of ducting could also aid in the cooling of the assembly. Further, the gear on the generator could have an electromagnetic clutch so that it cuts out below turbo efficiency thereby avoiding some of the ill effects of an exhaust restriction.

Of course, the exhaust restriction would still eat some efficiency out of the motor. So would pushing a turbo be better or worse than a belt driven alternator.... It's just a really fun puzzle to think about, and incredibly difficult to pull off.

[theholycow]

That chain drive transmission system sounds heavy, complex, and lossy. I think, when it's all said and done, this idea is barking up the wrong tree...specifically, the "more out than in" tree.

Using exhaust heat might be a way to recover some energy that's being wasted.

[scho]

Soak enough heat though, and the catalyst might lose some of its effectiveness.

Either way you go, you have to give something to get something. Hence, it's a really fun puzzle.

[theholycow]

Yeah, you'd have to soak the heat downstream where there's nowhere near as much of it, there's no room for equipment, and you'll still change the exhaust gas density which would produce some backpressure I guess...

[RoadWarrior]

You'd just end up with a real need for a coffee can exhaust tip, let it spread out as it slows down, such that you get the same momentum per unit length of pipe. At the hot end, you have small volume, small mass, at high speed, giving you x momentum, at the cold end you have large volume, larger mass, low speed, giving you the same x momentum..

[scho]

I don't know the answer to this, so I'm going to ask. Do you need to have your alternator running all the time? That is to say, could you go without it for short periods of time (ie. acceleration, idling, etc.)?

If you could, then you might be able to get away with adapting the electro clutch to the alternator as it is, and then only run it when you are at peak efficiency. And even then, it can cut in and out if the system is charged and happy. And then like every other system out there, when charge gets low, it just reverts to an always active state and constantly puts charge into the system (in the case of low charge or poor battery function).

How hard would it be to put an electro clutch on an alternator? Can't be that tough.

[dkjones96]

The clutch is easy, the pulley is hard. The vast majority of clutch pulleys are large diameter which isn't what you want on your alternator, especially if you are going to be only using it when you need it. It'd be MUCH easier to make your crank pulley clutched but unless you went with an electric water pump(or have one of the few cars with a timing belt/chain driven pump) that's an extremely dumb idea.

Why not wind yourself a lightweight rotor and accompanying stator and run direct drive? Make it high voltage, low current and run the 3 phase through a transformer(or 3 single phase) then rectify and regulate as usual. You'll move some of the heat generation from the windings to the transformers so heat soaking the alternator won't be as much of an issue. Making a stator that will hold together at 40-50k rpm will be the hardest part.

Use something like microwave transformers(can be had for free) and have peak alternator output be around 5kv.

[scho]

So it would effectively be slowing down the rate at which the alternator is spinning.... good call. And those pulleys are so damn small on alternators. The only other option beside clutching the crank pulley would be to make the crank pulley even larger to compensate for the gearing change. And a huge pulley would be heavy, which once again would be an extremely dumb idea.

Someone has to make a small clutched pulley somewhere in the world.

[RoadWarrior]

I'm not sure that spinning a clutch pulley would really be any less load on the motor than spinning the armature of the alternator with the field coils turned off, which the ECU will do from time to time, depending on load and state of charge... If one does a lot of highway driving, one could wire up a relay across the TC lockup solenoid, and use it to trip out the field coils such that you second guess the ECU and only charge when at light load cruise... but you'd have your battery light on all the time.. and you'd only get about an hour out of the battery in a wet day stuck in city traffic.

[thecheese429]

Originally Posted by onegammyleg

But seriously , the whole idea of running an ALT from exhaust gasses is not a very good one.
As pointed out in other posts , exhaust gas flow would be too little to turn it at idle or light throttle and it is likely that you rwould need a gear box to reduce the rpm to the ALT.
But that would again make for low output at any normal driving speed at lite throttle.

Even IF it did mechanicaly work, th epower needed to turn the ALT is not free.
The 1 or 2 HP (?) needed to turn it (at full output) would be shown as a restriction on the exahaust.
I would guess that the motor would run worse with that setup than just running a conventional belt drive.

What you need is to get FREE power !!! (or almost free is good too)

How about , running an electric clutch on the ALT pully.
So that it only locks up and starts charging at idle or deceleration.
The clutch can be switched in or out with a simple vac pressure sensor., and the parts to do the clutch can be salvaged off a air con compressor.
CHEAP MOD

KaChing , almost free power

Hmm, brilliant idea. I'll have to look into that one. I might try that with the power steering pump except with a speed lockout, not vacuum.

[theholycow]

Originally Posted by RoadWarrior

spinning the armature of the alternator with the field coils turned off, which the ECU will do from time to time, depending on load and state of charge...

Put more simply: No clutch is necessary because the alternator gets turned off when it's not needed already; it still spins when off but there's no load on it.

[scho]

That's a good point. Without a load, it's not all that bad.

Once again showing that it's hard to improve on what the automakers have sunk millions into researching.