Building my own hybrid

[burn_your_money]

So it was a really slow day at work and I found myself dreaming of a diesel hybrid.

I haven't done any research yet but this is my rough plan thus far.

MK2 Golf/Jetta, probably 1.6 TD
Stock diesel engine in the front
Use a rear axle from a RWD but rotate it so that the axle comes up into the trunk (90 degree rotation)
Hook that up to an electric motor which will be used to drive the car for acceleration around town and also be used for regenerative braking.
I was thinking a couple of deep cycle batteries for the power storage but I don't know how well they will hold up/how much power they can put out.
I'd probably throw on a couple solar panels even though they aren't very efficient.

Some thoughts:
1- Will the stock Vw tranny be able to survive being pushed around by the rear motor? I understand that since the input shaft is not turning gear lube will not be pumped/splashed to all the gears
2- How much power would I need to drive a motor to get the car rolling.
3- Anyone remember the rabbit that had an electric pusher trailer?
4- Will a rear differential be able to survive being rotated 90 degrees?

I've personally found that carrying around a lot of extra weight in the trunk of a mk2 jetta 1.6 TD did not dramatically effect my mileage so I am not overly concerned about that. I do like trunk space but for a commuter I can live without it.

I don't plan on charing the batteries other then through the braking and solar panels, plus possibly plugging it in(preferably to a windmill, solar panel, hydro electric dam etc)

So what's everyone's thoughts? Am I crazy?

[Turbinepowered]

First, I think it's a neat idea, but on a shadetree/hobbyist level build it's going to be buggy as all crap and end up being more annoying than useful.

For batteries, look at electric cars. Probably want to look at how they do throttle control, with potentiometers and controller packs and the like. You'll probably need more along the lines of 10-11 batteries to get a useful charge of the appropriate voltage. Most electric motors used to move cars operate on 90+ volts, so you need a fair number of 12-volt batteries to link in series to generate that voltage. Also, if you want regenerative braking, you'll need an AC drive motor. These are pricey (3-4 grand apiece :shocked:), and you need a specialized speed controller that's meant to utilize regenerative braking.

I doubt the differential would survive long with the pinion pointed downward, would probably survive longer if you flipped it 180 or left it in its "usual" orientation.

[cyrus #1]

My biggest concern would be making a MKII chassis properly handle the weight.  All of the gear you need would probably weigh 1000 lbs (I'm guessing a bit here).  So brake and suspension upgrades are a must.

With that out of the way, I've also thought of this quite a bit.  I think I would build a series hybrid rather than the typical parallel hybrids we see today.  :twisted:

[flapjack]

Have you seen the kid that put two 16v motors in a scirocco?
I love the build story, pretty funny.  The way he mounted the motor in the back would work for your idea (sub in electric motor for 2.0 16v in the back)
http://durocco.com/main.html
I think the bigger problem is controlling the whole mess. Do you want the diesel to be in neutral when the electric is pushing? COuld you control the power of both motors so they could run at the same time without tearing the car apart?

[Vincent Waldon]

Go for it Tyler !!

I investigated making a Voltswagen many years ago and as far as I know the state of the art has not not moved much:

- the typical motor is something in the order of 20-30 hp for highway cruising speeds
- they run at 90-120V in order to not need massive currents and therefore  huge battery cables at those power levels (746 watts or 62 amps@12V to a hp assuming 100% efficiency)
- this means 8-10 large deepcycle batteries
- control is usually done using a PWM controller with drive-by-wire capability, overtemp and overcurrent protection, regen control etc... Curtis seems to be the standard manufacturer.

Obviously not all of this applies if you already have a internal combustion engine in the front end... but the math is still worth thinking about... a hp is still 62 amps minimum at 12V.  This is likely why hybrids generally are fossil fuel vehicles with battery assist rather than the other way around.

Like I said... go for it... someone's gotta break the cycle !!


Vince

[itzdshtz]

I think that it would be a cool project.

The transmission would not last if you leave it in neutral but you could  leave it in 4th gear with the clutch pedal locked down with a electrical solenoid, there is no pilot bearing in the crankshaft that could wear out and the clutch plate will spin free.
As soon as you start the diesel, the pedal will release.

The extra weight in the back will easely be carried by the solid axle and trailer tires.

You may need a small electric pump to lube the top pinion bearing.

I think the biggest problem would be to get an AC motor with controls, maybe look at some electric fork lifts.

   Cheers   Herman

[jtanguay]

http://www.mrsharkey.com/  :wink:

if you could make a system that would turn off the engine at stop lights and use the rear electric motor to bump start the engine that would help increase a few mpg's around town  :wink:  :lol:

[burn_your_money]

if you could make a system that would turn off the engine at stop lights and use the rear electric motor to bump start the engine that would help increase a few mpg's around town  :wink:  :lol:

That is sort of what I was thinking, but even leaving the diesel idling wouldn't be horrible. I didn't expect to have enough power for any sustained highway driving. Maybe I need to go pretend to buy a hybrid and have a gander at the electronics and batteries

Good call on the forklift, my brother had mentioned that to me earlier, something about a Chevette and Ottawa.... I'll have to talk to him.

The thing I don't like about the Durocco project is it takes up a lot of room and there is no back seat.(IIRC) Although being electric it wouldn't be hard to run it in reverse and then just have no trunk.

I'm very confused about the solenoid and fourth gear idea... could you explain?

What about using a 5 speed but take out the fifth gear so I could just throw it in fifth and have everything turning? I need to look at Brokes page again. Maybe an electric lubricator would be the easiest and most efficient.

Hopefully these thoughts are semi logical, I have to run to class

[idgtd]

Hey burn, I work in hybrid vehicle research and development, and your proposed configuration is def. a feasible one. It's called a parallel through the road hybrid. We used that layout on our ChallengeX competition car (look it up, we (Mississippi State) won last year) and it works great! We used a GM/Vauxhall 150hp 1.9L engine driving the front axle with a 67hp AC induction drive powering the rear. As for leaving the engine idling, that's what we do, and we still get 38mpg (in an SUV!).

[thedeezel]

I would try for a Caddy hybrid, it would give you plenty of room in the bed for your batteries, build them onto a rack behind the cab for central weight distribution, using a rear wheel rear axle, you could tilt it up at say 30 degrees (just a guess) and cut a hole in the bed and with the length of the bed you wouldnt have to have the pinion at 90 degrees, so lube in the diff wouldnt be a problem.  Find a bedcap and put the whole system in the back.
The biggest difficutly would be the switch from diesel power to electric and back upon demand.
I would think the tranny would be fine coasting under electric power, it would be no different that a car being flat towed behind a motorhome in nuetral, I have seen cars that have been towed for their entire life and have had no trouble.
I have a friend that is a forklift mechanic, I will talk to him about the charging and drive systems they use.
The project is complex,but definately do-able.

[jimfoo]

Why not keep the diff at it's normal angle and use a chain drive, although the motor would have to be mounted to the axle so the chain would retain tension.

[burn_your_money]

Thanks for all the positive feedback, much more then I was expecting

I'm going to go to the library later and try and get some books on forklifts.

Is this your car idgtd?



Just so happens I own a Caddy that needs an engine. And I have a topper for it.

Chain drive might be a better idea because I could manipulate the drive ratio even further

[TedV]

so many links to post for ya, so little time.  And me being at work without said links makes it even worse.

You can have the electric motor under the chassis to save your hatch or trunk space.  ProEV.com uses the stock rear subaru diffs both front and rear. It's an AWD electric sedan race car, I know it from my years doing track side race tire service.  Diff in front is upside down so checking fluid level is a pain.  You can use the regular VW trans with adapter plate for the electric.  if you want regen braking easiest is AC motor, but $$$$ and more complex batteries and electronics, metricmind.com has surplus AC systems.  If you want regen with a DC motor look into a seperatly excitable DC motor, sepex for short.  I've heard of some people working on regen for the brushed DC motors, like the advanced DC 8 and 9's, but be prepared to replace brushes often and possibly fry components.  

Google is your friend.  if you want to build a complete 3 wheeler, search out the XR3 by Robert Q Riley of Pop. Mechanics fame.  He is working on plans for a 3 wheeler, 3 cyl diesel thru a VW Bug trans running front wheels and a advanced DC8 powering the single rear.  If you want regen braking, it is more effective using the elctric motor on the front wheels.  Front wheels give 70%+ or so of the cars braking power, plus, have you ever yanked up on the park-brake handle trying to stop the car with the rear wheels?  if not, try it and tell me your experience spinning thru the ditch.  :lol:    

Several years ago the auto shop teacher from the Philidelphia High School was asking questions on TDIclubs forum.  he had a kit car that was to be electric front wheels (AC system) and a TDI to the rear wheels.  I lost a lot of respect for the folks at TDIclub as they ripped him a new one with his questions.  Nice to see all the positive feedback here.  As usual there is more than one way to do it.  tons of pro and cons to each system, just hope you have the time and $$ to do it.  Even if you don't get to do it, makes for some fun thinking. :wink:

I know some of the guys on the UT Knoxville ChallengeX. they never would let me drive it....  wonder why... oh yeah they know me  :twisted:  :lol:

[znate]

Heres the thread about the electric conversion i was telling you about, although its not a chevette. I was re-reading a bit today and it seems things got a bit jumbled up, maybe when they switched boards. also a lot of the pics are missing.
He made a few youtube vids, if you search for forkenswift they should come up.

I think if you used your caddy you might possibly have room to mount an electric motor under the bed without  needing to turn the diff. I've heard a 10hp electric motor is big enough. might be able to get your batteries under there too, maybe raise the floor of the bed a bit, i honestly don't remember what it looks like under there.
I'd look into a Zilla controller to drive the electric motor, ive heard theyre the best, expensive though.

[thedeezel]

I thought about the chain drive too, just figured it may be a weak link and add more compelxity, if you were to go with a chain drive, I would mount the electric motor over the diff and use a spring tensioned idler gear to keep tension on the chain.  With the motor mounted under the bed, it would leave more room for batteries, would you use deep cycle marine batteries or use large tractor-trailer or agricultural batteries (I was a John Deere combine mechanic, those bateries are LARGE and have lots of amps available).
Now my wheels are turning...great, one more thing to keep me awake trying to figure out.