Hybrid Discovery Unlikely - but it's coming

one issue I see, to my layperson view, with an electric motor on each wheel is the loss of torque as traction is lost on various wheels assuming 4 individual motors would be smaller(torque and power) than a single central motor through gear box and diffs.

They would be great when all four wheels have grip but what happens when only one wheel has traction? You only have one small electric motor trying to move the car, the torque of the other three motors can't be transferred to the wheel that has grip.

Sound logic or not....?

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Originally Posted by gghaggis

The concept of electrically-powered or enhanced vehicles is often linked to batteries and their attendant problems because that is what most people automatically think of as the storage solution. But hydrogen-fuel cell and more-so supercapacitor technology is almost at the point where it could make batteries redundant.

An electric or electric-hybrid using graphene supercapacitors would not have all the baggage associated with battery manufacture, weight and disposal. So as a platform for advancing road technology, you need to consider electric (hybrid) independent of the battery issue.

Cheers,

Gordon

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AFAIK Oshkosh already have electric drive (diesel-electric) offroad military vehicles using ultracapacitors...

[ame=http://www.youtube.com/watch?v=RAqxJkwKMRA]Oshkosh diesel-electric hybrid for Baja 1000 - YouTube[/ame]

By having a small (diesel) engine connected to a generator you can run it at constant load (optimal conditions) and significantly reduce emissions. If needed it could be run on a renewable fuel like vegetable oil, biogas or ethanol.

https://www.aulro.com/afvb/images/im...013/11/393.jpg

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Originally Posted by SBD4

one issue I see, to my layperson view, with an electric motor on each wheel is the loss of torque as traction is lost on various wheels assuming 4 individual motors would be smaller(torque and power) than a single central motor through gear box and diffs.

They would be great when all four wheels have grip but what happens when only one wheel has traction? You only have one small electric motor trying to move the car, the torque of the other three motors can't be transferred to the wheel that has grip.

Sound logic or not....?

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Yes, good point, sound logic. The problem could be overcome by using more powerful motors, but limiting their output except when emergency one/two/three wheel drive is required.

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Originally Posted by Silenceisgolden

Excellent question, Meken. 500,000 Diesel-electric locomotives can't be wrong! If the process was not fuel efficient, I am sure the train makers would not have gone that way.

With modern electronics, just imagine the algorithms that could be used in off-road vehicles! It would be the ultimate in efficient traction control. Much better to apply power to the wheel with best traction rather than applying a brake to the wheel with least traction.

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The popularity of diesel-electric transmission on railways is not because of its efficiency, although it is undoubtedly as efficient as any alternatives, but because it solves the problem of producing maximum torque at zero rpm (inherent in some types of electric motor), needed for starting, and at the same time solves the problem of driving six axles in two bogies without gears, shafts, or inefficient hydraulics.

I suspect that electric transmission could be no more expensive than current systems, especially for a four wheel drive, but I can see some potential problems - motors, cables and the alternator would use a lot of expensive copper and be quite heavy unless quite high voltages were used. That in turn leads to potential problems with safety and operation in a wet and dirty environment. I'm not saying this could not be solves, just that it would be expensive to solve. RFI would be a potential problem, and could cost quite a bit to solve.

John