Low cost AC drive motor / homebuilt hybrid retrofit
 

I have admired the persistance and determination to save a few bucks that has gone into project forkenswift. I think I would not be up to that kind of project but a question surfaced in my mind today. It might be there but I did not find the answer in my searches of the archives. GM is now using the alternator as a motor in some vehicles and calling it a hybrid. Just how much would it take to turn a 165 amp 12 volt alternator into a 3 phase motor and how much power might a person get from it before it got too hot. I would like a 5-10 hp AC motor and what the heck maybe a guy could make one.

My new to me 2001 Saturn has impressed me very favourably and I think the addition of a 5 hp pusher wheel might be in the cards. I have seen the picture of the Insight with the fifth wheel.

Anybody turning ordinary alternators into motors. It would certainly take the right controller and some "field current" with the original rotor.

I am looking for low cost too but maybe this is not the place to look.

Thanks, Ernie

I have thought about this a lot myself, and have come to the conclusion that the best idea would be to install a *small* AC or DC motor, and connect it using a drivebelt, to the crankshaft pulley than connects to the alternator and so forth.

One thing to consider with this option is that, it would only work when the engine is on and running, and therefore, one big advantage (prolonged engine-off coasting with electrical drive to stop/reduce speed loss) would be lost.

Another thing to consider is that, if you are driving with the car at 2000rpm, it might take 10 'units per second' of fuel to just turn the engine at 2000rpm, and then an extra 2 to give a lot of acceleration. This means that the effects of the motor may be less than expected. A more positive way to look at it is that, even if you use a fifth wheel or put the motor on or near the alternator, the fuel savings would be identical, as long as you are using the engine in gear while using the electric motor or fifth wheel.

If you keep thinking about this, one possiblity (if you have a manual gearbox) is to get the motor attached to the output shaft, before/on the diff (would need some custom machining), but this would give a brilliant way to power the car with the engine in neutral, or off, or with the engine running, and could also be used for regen if you had the correct type of motor.

Good luck with this - this is something I personally plan for my car, likely in 2008. Just waiting for word back on price from the large form factor NiMH supplier I found :)

I don't have much to offer directly, but the question of alternators as motors has come up on the EVDL. You may find some info by searching the archive here: https://autos.groups.yahoo.com/group/ev-list-archive/

If I recally, the consensus was that a conventional alterntor would make a poor motor.

I'm with you on that, landspeed.

A potentially simpler option would be to attach (via pulleys & a cogged belt) a small-ish motor to the drive shaft/half shaft. Use a freewheeling clutch on the motor, and you've created a cheap dual mode hybrid.

The car can be driven electrically with the engine off and the transmission in neutral, and when being driven by the ICE, there's minimal drag on the belt & freewheel assembly.

I've looked in & under the hood of my car - the problem is there really isn't much room for such a setup. It's too crowded in there.

To be honest, I've been thinking about how to retrofit a hybrid too. Just thinking.

If there was some way to reuse the gearbox with the motor/generator, i.e. have it coupled to the transmission input shaft with a smaller clutch, then you might have a manageable and efficient system.

1. you could lose the alternator.
2. you could lose the starter (trans in neutral, engine and motor/generator clutches engaged)
3. you could use the motor/generator as a motor at higher speeds and not make it spin faster than necessary.

Maybe a chain sprocket (and a grease shield) could fit in behind the throwout bearing in the input shaft? That wouldn't be too fancy of a machining job.

There's not much room. I've looked :)

I've thought of this many times as well so it must be a great idea :D , but alas, I must agree with the others on the alternator thing. The first problem is 165 Amp x 12V 'motor' even at 95% effiiciency would give you less than 2.5 HP. If you tried to double it, the motor would likely burn up. Second, you'd have to replace the accessory belt with a much larger cog belt or metal belt of some kind. Third, you'd need a specialized 3-phase AC motor controller. They're pretty pricey.

Now having totally rained on your parade, let me shift gears. A different motor may yet have some promise. Go DC if you need to keep costs down. If you go AC, the motor and controller can run as high as $10K. The biggest problem seems to be how to turn the wheels with the motor (and vice-versa). All front-wheel drive cars I've ever seen give you no easy way to do this. Maybe you could use a cog belt to connect the motor to the inboard end of a half shaft (doing both would mean using 2 motors). The problem with this is that the half shaft pivots up and down. Unless you get the geometry just right to move the motor(s) along with it, you'd quickly 'throw' or destroy the belt. This is not impossible, just a bit of engineering and fabrication.

Alternatively there's the idea of placing the motor into the wheel hub, or on the brake rotor somehow. If you haven't totally given up on an AC controller, and you could somehow add a second rotor, you could attach magnets to the rotor and make a three-phase motor with home-made coils. The reverse has been done elsewhere on the web where folks are making windmill alternators out of surplus brake rotors, magnets and coils. This approach has some pros and cons, but with ingenuity, could be brilliant.

Of course a much simpler approach would be to take a rear-wheel drive car and simply attach a DC motor to the center drive shaft, maybe even inline with it. This is a mostly unexplored configuration. With the kind of experimentation needed to make something like this work in the long run, something that is easier, cheaper, quicker-to-see-results in the short run may turn out to be invaluable.

Not necessarily - only if you want 2-wheel drive. And if you did, you'd have to control the motors somehow to get differential action in turns. I'd just KISS and use a single motor on one half shaft.

On my car (don't know if it applies to all FWD cars), the inboard half of inboard CV joint is pretty big. Maybe enough room there for a cog. The driveline travel/movement issues go away, but belt routing then becomes the problem to solve.

Or an AWD car. Such as pretty much any old Subaru, or a Tercel or Civic 4WD wagon.

Another idea I've been mulling over is attaching a cog to one of the rear wheels. You'd still have the issues of motor & belt placement (and suspension travel), but I'd think it'd be easier to solve with the extra space at the rear of the car than in the typical engine compartment of a compact car.

That's what I meant.

If you were using 2 motors and they were putting out the same torque (read getting the same current), there wouldn't be a problem. Diffs are needed with a single motor because of the asymetrical torque buildup on a non skid surface. Something has to give.

It will work as long as the transmission is not in neutral, otherwise the center diff will spin. [edit: but may not present a problem :confused: ] Alternatively, you could get a 2WD version (no xfer case or center diff) and put the 4WD rear diff/axles in back and then put the electric motor there. The Tercel and Civic sound good. The ScoobyDoos are pretty heavy and are harder to find 2WD versions, but it could work. I think I'd go with a Matrix/Vibe over a sube.

I found a product that clames "up to 600 amps at 48 volts to the electric motor for acceleration"

https://www.sigmaautomotive.com/elect...trocharger.php

Estimated retail is $2800.00 USD.

I did a google search for "retrofit hybrid"

Ryland -

I found this thingy awhile back and thought it was similar to the Saturn Vue "mild hybrid" setup. So far, it has been "in development" since I saw it over a year ago. Their last progress report does look promising, though :

Jan 24th, '07: From the Inventor: We have been awarded a grant from the State of Texas to develop the Heavy Truck system and the prototype will be ready by the end of August. We are also expecting another grant from the State of Texas on the Mild Hybrid kit and Austin Energy will be the first fleet customer to get our Plug-In hybrid kit. There's alot of things going on and we are getting closer to the launch date for the general public.

(Lots of other fun/whacky stuff on that site, too)

CarloSW2