[Mahonroy]

Hello, I am new here and my name is Matt. I'm still reading around and learning a few things, but figured I would make a post to see if I could get some ideas/advice from you guys.
Quick background on me, very mechanically inclined, and have a business designing and building turbocharger systems for cars (so have access to a lot of fabrication tools). I'm confident I can design and build the mechanical portion of the build, but I'm still learning about the electronic side.
So I have this spare 2003 Hyundai Elantra (2.0liter) that I want to use as the project car. I want it to be a hybrid, and have a 10-20hp electric motor assisting at all times (with the ability to regerate power under breaking as well). I'm trying to acheive my goal and keep it as simple and inexpensive as possible, but if it goes over budget its ok.
What I was going to do is machine a new crank pulley with an extension on it, mount a electric motor in a similar fassion to the motor as the alternator, power steering, ac, etc. is mounted, and connect it via a belt (possibly toothed if necessary like a timing belt) to the extension on the crank pulley. This way the electric motor would be in direct contact with the drive train of the crankshaft at all times. The only thing I really need to figure out still is a good tensioner system for the belt, but I don't forsee this being too big of a problem.
I was also wanting to base the electric motor output off the TPS sensor.
My main confusions are how the regenerative breaking system is going to work, and what type of electric motor would be best for this application. If you have have a relay turn on to flow current through the electric motor to drive, how do you have it to where you spin the motor and have it generate electricity back into the batteries, since the electrical circuit would be the same between the two right?
Any help or advice is greatly appreciated, thanks!

[Mahonroy]

Anyone got anything they can chime in on?

[Ziggythewiz]

Most hybrid plans are bad ideas because while you think you'll get the best of both worlds (questionable), you'll definitely get the worst of each as well.

Usually to do regen you either use a clutch that makes a generator pull on the shaft of the motor when you want to brake, or you use a motor and controller with built-in regen so the controller handles whether you are adding or subtracting power from the drivetrain.

[madderscience]

There are many hybrid models on the road these days. What do you expect to achieve that you cannot get for much less from one of these? If the answer is a learning experience, go for it. If you want to hybridize something that is not available from the factory that way, that is another potentially legitimate reason, though there are plenty of small and midsize hybrids out there. If it is a "better" hybrid you have your work cut out since you are competing with hundreds of millions of dollars of engineering and development work.

that said, The best approach would probably be to find an AWD vehicle and drive one end from the gas engine and the other from an EV drivetrain. Managing the two drivetrains for optimum efficiency will be the challenge, as will keeping the EV drivetrain light enough to avoid a net loss in overall economy. You will need an AC drive system (several types available, most are very expensive though the HPGC/Curtis system is very competitive) or a shunt wound (golf cart) setup. The most common DC series wound motors used in conversions are not good for Regenerative Braking.



Good luck.

[Mahonroy]

If it all works out good, then I would like to possibly produce a "kit" of some kind.

What are the flaws in my design though? Although you are telling me good ways of doing this, whats wrong with this way?