Hi folks,


So let us say I lived in a country that had no hybrid electrics or worked for a company that had suddenly noticed they needed a hybrid electric, yesterday . . . this is how I would start. Think along the lines of 'roll your own hybrid' or how to make a "Junkyard Wars" or "Mythbusters" hybrid electric:

1) start with a real-wheel drive, manual transmission vehicle
2) fit the permanent magnet, electric traction motor so it is coupled to the drive-shaft
3) lock the manual transmission into the highest gear
4) rig up the clutch to close at speeds above 45 mph
5) remove the starter and replace with a heavy-duty, permanent magnet MG
6) take all accessories off of the belt drive
7) put largest possible, heavy-duty, permanent magnet MG on belt
8) replace AC compressor with a 5,000 BTU window compressor
9) use a 1 kW inverter to drive 5,000 BTU compressor
10) remove coolant thermostat and replace with thermostat switch
11) drive water pump from motor actuated by thermostat switch
12) use high-voltage, switching inverter connecting batteries, traction motor and alternators
13) use pair of Linux computers to operate inverter, clutch and engine controls

Another approach would start with a 4-wd vehicle and use the redundant wheel drive for the electric motor assembly. However, there would be a problem of balancing the ICE and electric motor assist unit, which is not impossible but tricky.

Comments? Questions?

Bob Wilson

Operation Iraqi Oil Freedom:

Automatic, stock, project car.

My other 1500 cc car:

Automatic, stock, backup car.
Free speech, dialog and knowledge thrives without the poison of SPAM.

Bob,
Nice job!
I'm not as electrically adept, so I would do it like this.
1)Start with a pickup-nice long driveshaft to work with and a bed to mount and carry the below items..
2) Buy a 10-20 hp electric motor -used-just a cheapo motor, nothing special; . It would have to be set up to run on 120 v DC.
3)Buy about 10 100 amp(1200 watt) junkyard alternators.`
4) 10 12 V motorcycle batterys.Easier to deal with the smaller batterys.

I would mount a series of clutched pulleys to the driveshaft to drive the alternators.They would have to be "geared" so that they were producing 75% to their 100 amp max at about 35 mph or so. Not really sure how to clutcxh them; it would be easier to clutch the pulley on the alternator shaft, but then it would constantly dragging 5 belts/pulleys etc. One belt would drive 2 alternators with would be mounted in the bedstill use the bed-(this junk would be under a false floor). There would have to be a tensioner on each setup to accomodate drive shaft movement.
The electric motor would drive the driveshaft in the same way the alternators are driven.It would be nice to have a solid chain, or toothed belt drive-like a Harley-, but...
The batteries would be in the bed-false floor etc.
Instead of using a computer to do all the switching, I would do it manually. Using a ECU to do the switching/deciding is beyond my capabilities.Toyota must have spent many millions writing their Prius program.
This is how it would work.
Starting from a stop I would manually engage the electric motor as I was pushing down the gas pedal.I might be able to literally "tie" the pedal to the electric drive motor, and maybe it would be possible to match electric motor power/speed to drive shaft speed so the electric motor wasn't straining its guts out. The motor would give a 5-10 hp boost and save gas in stop and go.
Braking and regen would also be manual, but it might be automatic to a degree(but probably not).. I would have to have a manual dis-engage thumb switch for the alternators on the steering wheel. Completely manual engage/disengage thumb switches on the steering wheel might be the way to go, with no automatic switching slaved to the brake or gas pedal.
That is it.It would be heavy-maybe 400 lbs-. It would be so heavy that it might not make dollars and cents,sense- .It sure would be nice to have MG tied to the driveshaft, but then I would have to figure out how to program the switching. Maybe-maybe I could manually switch them??
Oh well,luck.Charlie

Bob;in your very comprehensive list, you forgot something crucial: what type of batteries to use.

This is no trivial matter. The least expensive would of course be the flooded lead-acid. It would be the heaviest pack by far, specially if one uses one of those deep-discharge batteries. A "standard" lead-acid would have a very short life as a traction battery.

That would leave you with either NiMh or Li-ions. Quite expensive, but most importantly, they require a sophisticated charging algorithm, temperature sensing and ensuring that the charge balance across the cells remains within certain tight limits.

The true smart man is the one who appears to be dumb in front of dumb man who appears to be smart.

I had left the batteries out because I would use a step-up inverter to convert the 48 VDC to the voltage and frequencies needed by the various MGs. By standardizing on a 48 VDC power bus, a lot of safety issues are resolved as well as off-the-shelf battery systems. The US phone system is based upon 48 VDC battery systems for power during an outage.

I have assumed the battery subsystems would be ECU controlled. Other than a "state of charge" to the vehicle controller, "about to isolate" signal and sense "regenerative recharge" signal, they would be self contained assemblies that could operate in parallel. The vehicle doesn't care what battery chemistries are used to provide motive power.

IMHO, a low performance, low cost lead-acid battery system might be in the starter car. Later it could be augmented and/or replaced by one or more advance chemistry battery assemblies.

Bob Wilson

Operation Iraqi Oil Freedom:

Automatic, stock, project car.

My other 1500 cc car:

Automatic, stock, backup car.
Free speech, dialog and knowledge thrives without the poison of SPAM.

Bob, the lead batteries sure would be the way to go on a 1st try.If they were "fouled up' during developement-for any reason-they would be a lot cheaper to replace.
You know, I'm not so sure the much more expensive batteries are waaaay lighter.
The DIY electric car builder used Lead batterys initially.He used 1300 lbs of Lead batterys-29 Optima batteries. They stored 18,000 watt-hrs, and he could drain 14,600 Watt-Hr from them(down to 20% charge).He could drive 90 miles with the 3300 lb Honda(started at about 2000 lbs I think) on one charge-he did have regen capability.
Our Prius has a 1500 Watt-Hr battery-it weighs 90 lbs- 16.6 watt-hr per lb
18000/1300=13.8 Watt-hr per lb for cheapo lead batteries.(Well,the Optima aren't cheap,but...)
Where is the weight advantage?What am I missing here? Do the Lead batteries have that short a life span? They are certainly cheaper-18000 watt hrs for $1100- vs our Battery pack 1500 watt-hrs $2500?
I must be missing something?What is it?Thanks,Charlie

What is the total weight additon here? I have a 1998 Impreza Outback that I have thought might make a great do-it yourself hybrid platform, or all electric! Beef up the suspension, and put the battery packs over the top of the axles, or just in front and back of them. The rest of the weight seems like it may be 500 or so pound just from guessing. What do you guys think?