DIY Open Source Plug-In Hybrid

[JethroBodine]

I third the Caddy being a bit small for this build. Swapping out the front of the 2wd truck to 4wd isn't any harder than other ideas that are being kicked around, especially with the right donor vehicle. Also, if you can get 40+ mpg out of an S-10 truck, that would definitely get some attention.

[bennelson]

Of the links that MetroMPG posted, this one Douglas Hartley's 1994 Skoda Favourit Elta Pickup seems to be closest to what I was thinking.

Any of the EMIS systems that I've seen posted all look to be rather expensive, while adding NO "electric only" range - just an electric boost at in town speeds. The two links showed the cost of adding the EMIS system as being $10,000 and $15,000 of cost added on top of the vehicle.

Also, the rear-wheel drive connection with a series-wound motor doesn't provide for regeneration. I think that for a plug-in hybrid, regen would be an important feature, not just for start and stop, but for cruise-charging as well.

Can somebody with a better understanding than me of various types of electric motors help me with something? In people that I have talked with so far, it seems to come up that a DC Series-Wound motor has enough torque to bolt it right to the rear differential of a car and drive it directly. DC motors are usually lower voltage than AC (so fewer batteries)
Apparently, AC motors don't produce as much torque, so you still need a transmission and be able to go through the gears to produce the torque to give you the required torque to accelerate.

Does that sound about right? How about a shunt-wound motor, or brushless DC?

It seems to me that a series hybrid is pretty straight forward - build an electric car (AC/DC, front-wheel/rear-wheel, doesn't really matter) and add an appropriate generator.

To do a parallel hybrid, it becomes more complicated, but also opens up more possibilities - does the electric motor go on the front or the back? Is the ICE front-wheel or rear-wheel drive? How to arrange for cruise charging?

Of vehicles that I already have access to....

I could just add a generator to the Electro-Metro. My experiments with the LP generator showed that it can work, but I didn't care for the noise, I didn't have an ideal place to mount the LP tank, and I never got that used generator to run as well as it was supposed to. The car would still be powered by a brushed DC motor. That means brush-wear over time, and no regenerative capabilities. But no regen is not a big deal when there's a generator in the trunk. It would be a BAD setup for big hills. I test drove a RAV-4 electric in skiing country in Pennsylvania. Without the regen on the AC motor in that vehicle, I would have been on the brakes the whole time going down those hills!

That wouldn't be too bad in my area, as there's not a whole lot that's super-steep, but if I wanted to drive-it across country (out to the Mother Earth News Fair at Seven Springs, PA, for example) it would be a problem.

I think a generator like THIS would work (as long as I kept my speed reasonable.) I measured, and it would fit in the Metro. I'd still have to do a fair amount of sound-proofing, routing the exhaust, etc.


I also have a Chevy S10 pickup truck. It has a 2.2L gas engine and 5-speed manual transmission, 2-wheel real-wheel drive. I have an old diesel engine, naturally aspirated 2.4l from a Mercedes 240D. The plan for too long has been to put the diesel in the S10, to gain the fuel economy, possible use of bio-fuels, and other advantages that a diesel provides.

That's not an ideal setup for a hybrid, though. I could do an "EMIS-style" hybrid on it. I would be able to find a large DC series wound-forklift motor
at an affordable price. I think a friend of mine still has a 12" diameter one about. That motor could be run at 48V on up.

Since the transmission could get put in neutral, it would be very easy to run on just electric. (The EMIS system requires that the vehicle be automatic transmission and 1996 or newer to use throttle info from the OBDII.)

At that point though, the motor would be driving the differential AND spinning shaft going up to to tranny. Perhaps some sort of freewheel clutch could be used?

I still like the idea of a front-engine, front-wheel drive vehicle and adding a motor to the back end.

At this point, it seems like only a beefy series-wound motor would be the right thing to plop onto the rear axle. That wouldn't allow for regeneration. It would allow for a certain range on electric only, and firing up the ICE once the batteries are discharged. That would basically be a parallel version of the Volt (plus the potential advantage of four-wheel drive.)
Without use of non-fossil fuels, that's not much of an advantage over something a person could just run out and buy right now.

If it was a front-wheel drive hybrid, with a diesel engine (for fuel economy and ability to run on bio-diesel or veggie oil) it could be a vehicle to use ZERO fossil-fuels! Now that's starting to get into advantages over a Volt or Plug-in Prius!

What about regeneration though? It seems a shame to not be able to capture/recapture some of the energy from the ICE system. How about an alternator that runs a charger for the battery pack (or custom, high voltage output alternator) to load the engine a bit at cruising speed? Good idea, or starting to get too complicated?

Keep your thoughts and ideas coming!

[bennelson]

Oh, another thing I keep thinking about, but forget to mention is power steering/power brakes/ and anything else that normally runs off the engine.

In an electric car with a generator added, all those things are already designed to run without the engine. (My Metro has manual everything, except for power brakes, which was easy to correct by adding a small electric vacuum pump.)

In a parallel hybrid where a person would want it to be able to run either with the engine on or not, steering and brakes would need to be manual to start with (more typical on a lighter/older/simpler car) or converted to manual (such as swapping out the steering mechanism) or converted to electric (like I did with the power brakes on the Metro)

For me, starting with the manual everything vehicle would be the easiest way to go. A modern, front-wheel-drive crossover might be the MOST difficult to convert to still have steering and brakes with the engine off. I think that's also one reason why the EMIS system is designed as a "boost" instead of having any electric-only range - it means the original steering and braking systems never have to be modified in any way.

[bennelson]

Here's another hybrid link I missed:
Brucey's Electric Assist - a belted plug-in hybrid

I read through the entire thread, as there was plenty of good general hybrid discussion, including a reference to diesel front-wheel-drive.

[roflwaffle]

I dunno about a shunt wound motor, but I think PM motors are too wide to package inline with a RWD output shaft at the power outputs needed, although they can do regen.

IMO the easiest way to do everything is to drop a small diesel into your S10, run manual accessories, put a series DC motor behind the trans, and run regen off of the driveshaft (Unfortunately the original link is gone but all the basic info is there).

You would need to fabricate mounts and an adapter for the engine, DC motor, and rewound alternator, plus all the stuff on the EV side that you're already familiar with. It would be the least amount of work, but also less efficient and slower because the DC motor will be pulling more current at lower speeds than one connected to a transmission, and the engine would need to go through the relatively inefficient RWD setup to put power to the road.

Running two separate FWD setups would be more efficient (unless you choice of transaxles is really limited), but you would need to fabricate way more stuff, and unless you could automate the shifting of the motor somehow (without an automatic transmission since that would trash any efficiency improvement) that would be a pain, although doable since the engine and motor would have significantly different shift points. For a common and suitable pair of VW transaxles (ASF for the engine and GC for the motor) the shift points for the engine would be at 10, 20, 30, 40, and 50 mph, while the transmission for the motor should shift at 25, 40, and 60 mph for best efficiency. It would be kinda weird if you were using both, but I guess e-2nd, e-3rd/m-2nd, e-4th, m-3rd, e-5th, and m-4th wouldn't be impossible. Kinda like driving a 4WD vehicle or big rig, just a bit more complex.

Oh, and spinning the output shaft of a RWD trans shouldn't induce too many losses, at least not enough to consider putting another clutch inline IMO.

[brucey]

So is the Diesel Conversion on your S10 not going to happen ? I thought that was a really cool idea. I have a friend who was looking at putting a VW TDI Into his, hooked up to a Toyota transmission.

[bennelson]

Originally Posted by brucey

So is the Diesel Conversion on your S10 not going to happen ?

No, I'm still planning on doing that. It's just been the big project on my "too many projects" list for a pretty good while.

If I did do an EMIS-style hybrid, I would do it with that truck with the Mercedes 2.4l diesel engine. With the manual transmission, I could do an "EV ONLY" mode with an electric motor on the back and power from the batteries, charged from the wall.

I'd need to do a power brakes setup similar to what I already did in my EV Metro, and I'd have to do something about the power steering in the truck.

Come to think of it. That setup would also create the "Ultimate Starter" as I could "bump-start" the transmission with the series-wound motor.

Another dumb question. I thought I heard that diesels don't create vacuum the same way that gasoline engines do, so if you swapped out a gas engine for a diesel, you'd have to account for vacuum for power brakes and the likes. If you had to do that anyways, why not convert to electric so that you could have a diesel-electric hybrid with working brakes, whether or not the engine was on? (Do I have that right at all?)

[JethroBodine]

Yes they don't(create vacuum the same as gassers). The 1.6 I have has a vacuum pump where the distributor would be. I'm thinking of adding another tank for more vacuum containment once I swap over.

[MPaulHolmes]

My understanding of regen is that it can extend your drive by at most around 10%, and that's just if you are doing stop and go traffic in the city. It has other benefits though, like almost eliminating the need for mechanical brakes. Separately excited DC motors can do regen as well as AC. You have 2 separate pwm signals. One for field A, and one for field B. I really need to learn my motor lingo. Field A can have a very puny power supply of just a few amps. If you keep field A constant, then you basically have the equivalent of a series wound DC motor. Lots of torque. I don't know how common they are though. I think that's what Damien has.

[hamsterpower]

Some AC motors have plenty of torque to direct drive. But these could be (even more) expensive.

I've been thinking about the power vs manual brake issue for my up coming EV build. It seems to me that vacuum as the power is backward for anything other than gas ICE, where it was already available. It would be great if there was a electric boost or even a pneumatic (positive air pressure) brake booster. Air pumps are cheaper and easier to find, than vacuum pumps.

I believe the ideal layout for a parallel hybrid is a small diesel in the back geared high for cruise. Maybe with a PTO generator to charge as an option. With an AC motor driving the front wheels for the best regen potential. Use electric for all acceleration. Bring the diesel online above X velocity and let the electric coast anytime the diesel is enough. Nearly all braking could be done with regen through the front wheels and you have small drums in back to supplement and for parking. There would be no need for a starter on the diesel, just bump start. Probably no need for power brakes.
And in keeping with EV mentality- all the clean EV systems are up front and the dirty ICE systems in the back (under the bed?). Also this allows for decent weight distribution- heavier in the front, lighter in the back.

Paul- doesn't Jackbauer also use SEPEX? I agree that is a good alternative to AC.