Possibility of simple-ish hybrid conversion RWD vehicles...

[cRiPpLe_rOoStEr]

There was a hybrid conversion kit available for the Smart, with drum brakes to replace the rear disc brakes, already incorporating the electric hub-motors. After all, a similar setup would sound as the most reasonable option for a cheap hybrid conversion.

[rmay635703]

Originally Posted by cRiPpLe_rOoStEr

There was a hybrid conversion kit available for the Smart, with drum brakes to replace the rear disc brakes, already incorporating the electric hub-motors. After all, a similar setup would sound as the most reasonable option for a cheap hybrid conversion.

I thought there was only one made by a university? I wonder when if ever there will be hybrid kits coming to market? AKA grab a $400 ford or GM hybrid battery and conver the cobalt to rwd or the gm to fwd EV to assist in EOC.

[a8ksh4]

Originally Posted by cRiPpLe_rOoStEr

There was a hybrid conversion kit available for the Smart, with drum brakes to replace the rear disc brakes, already incorporating the electric hub-motors. After all, a similar setup would sound as the most reasonable option for a cheap hybrid conversion.

This would make for a nice almost-bolt-on mod for a lot of cars.

Just ran across these - 72v, 38HP, $800:
http://kellycontroller.com/car-hub-m...7kw-p-711.html
Linked to from here:
15" car hub motor $799 - DIY Electric Car Forums

[mechman600]

I think those hub motors might need one BLDC motor controller per motor. If so, that could get expensive fast at $600/each. And that's for the matching Kelly which I probably wouldn't go with.
But they can do regen braking.
Where did you get 38hp from? It's listed as 7kw. Maybe 38hp is peak output.

[cRiPpLe_rOoStEr]

In an aftermarket hybrid conversion aimed to FWD cars I'd always consider more suitable to provide the electric auxiliary drive to the rear axle, since it would deliver 2 main dynamic advantages: would provide better traction for higher-speed cornering and also compensate for the different weight balance which would come due to the extra weight of the battery packs.

[justme1969]

Well I tried to formulate the electric auxillary drive but getting a straight answer of potential torque for the motor seems impossible. Torque is linear and has alot of variables,too many for my brain to cypher. But the math I did was overcompensated to cover this anyhow.
So here ya go auto ninjas
1. Remove rear shaft of a transfer case. if it is slip yoke good luck sealing it up so should be internally held style, also concern with belt driven transfer cases are they have torque transfer issues 60/40 front to rear etc you will need to do some extra homework for them.
2. Purchase motor and drive to control it.
3. Determine gear ratio required, I have done a quick one "3.55/1 rear gears", with
" 195 70 14 tire" circumference aproximatly 78" new?? driven @ shaft speed of electric motor 1800rpm. = 498420 inches per minute approximatly. divided by 12 inches fer foot and 5280 feet in a mile times 60 minutes per hour. ok ya get the idea.
then factor in sprocketts or gears or pulleys...
4. Now decide how your going to use this if it is to only get up to speed then it is going to be different than if trying to keep @ speed after accel. or is it constantly powering vehicle throughout process. Most auto ninjas will say all the above and that will require serious engineering, luck, or endless trial and error.
5. The decision about use is important because controls must be added.utilizing the on, off, increase, and decrease buttons on cruize control make for nice Hiway rolling application. Newer vehicles with electronic gas pedal are great for the get up to speed variations add yourself a conveinient push button to turn it on and off. Electronic gas pedal switch can be added to a linkage style pedals also.
6. Design in a stop and emergency stop system. brake pedal works great for stop and is already wired into cruise control stop circuit. e-stop should shut system off though and should be in reach of the driver.
7. It is a motor therefore it is also a generator with all the proper parts in place, So how about a regenerative braking application?? here is where sophisticated electronic motor drives pay off because you can control regenerative brake application. instead of all on and off.
8. At some point you must decide how to feed you system so realize a good plan here will make all the differance on how you use the system and how many batteries you have in the car. How many amps your alternator requires to recharge etc. etc.

Did I mention all of this has some cost? a 5hp dc motor as I located was over $500 and this one would have probbably been just for testing as I dont believe it would have held up for more than a few months or so. Well I gotta go machine broke Just some food for thought people. trying to make your dreams a reality or something thats close LOL!

[serialk11r]

Originally Posted by cRiPpLe_rOoStEr

In an aftermarket hybrid conversion aimed to FWD cars I'd always consider more suitable to provide the electric auxiliary drive to the rear axle, since it would deliver 2 main dynamic advantages: would provide better traction for higher-speed cornering and also compensate for the different weight balance which would come due to the extra weight of the battery packs.

(Assuming we're attaching the motor to the hub or spindle...)
Not to mention that the rear wheels typically have less brake disk mass so you can end up with less unsprung mass. Also since the wheels don't turn like the front wheels, I imagine the wiring would experience less fatigue.

Back to original topic, an easy retrofit would be a modified alternator that spits out a higher voltage, either add it to the belt or modify existing alternator and then use voltage converters to power the existing electrical systems. Operating it at higher voltage will increase the efficiency considerably (a hydraulic energy recovery system isn't going to do very well in the efficiency department anyways). To optimize it further, if you have an e-throttle, you would want the throttle open in DFCO mode so you can recover more energy.

If I were retrofitting a RWD car though, I wouldn't bother feeding the power back to the rear wheels. Put electric motors on the front, feed all the excess power to the front wheels.

[nbleak21]

Originally Posted by rmay635703

As for a RWD, there are 2 spline double ended motors around, sandwhich one in and VOILA.
Ryan

That's a big negative, but I like your train of thought. Unfortunately this won't work, or at the most be very impractical. Reason being difference in tire rotation speeds (rounding corners, etc.) if you've ever driven a vehicle with a solid or welded rear axle, you'll know exactly what I am referring to...

However... My dream vehicle does utilize a double spline motor for a very similar application: configured inline with front and rear open differentials for a nice lightweight 50/50 AWD system!

[wmjinman]

Originally Posted by nbleak21

That's a big negative, but I like your train of thought. Unfortunately this won't work, or at the most be very impractical. Reason being difference in tire rotation speeds (rounding corners, etc.) if you've ever driven a vehicle with a solid or welded rear axle, you'll know exactly what I am referring to...

I believe we were talking about putting this "in" the driveline right behind the transmission (in a RWD). - before the differential. - Not in the axle. Wouldn't that be ok (differential-wise?)

[jray3]

Originally Posted by wmjinman

I believe we were talking about putting this "in" the driveline right behind the transmission (in a RWD). - before the differential. - Not in the axle. Wouldn't that be ok (differential-wise?)

Absolutely. The first 'modern' example of this that I'm aware of was done on a Subaru Justy (awd!?!), but that guy just proved the concept and moved on to the next sparkly idea. There is a kit from NetGain Technologies for vehicles with OBDII called the EMIS that uses a TransWarp motor- made for direct-drive applications.
I'm only aware of one hobbyist who built this, and his results were not impressive. Hybrid Conversion
Doing it with an AC motor like the AC50 should double the impact or better through adding regen to the equation...