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Is electric powered transpo the answer? 2

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Dinosaur

Dinosaur

Structural
Mar 14, 2002
538
I have read many things here where folks appear to think highly of electrical transportation. I don't think much of it because the energy needed is much higher than traditional solutions. On another thread, it was reported that only 15-20% of the input energy at an electrical power plant was used at the final destination (e.g. the fuel content at the electrical plant contained 5 to 6.7 times the energy used in the home). This is because they are unable to capture all the energy in the fuel, there are productiion losses such as friction in the generators and turbines, and there are transmission losses. I do not know what the ratio is for petroleum IC engines, but I am under the impression it is much better than this. Are there any automotive engineers here that can provide some comparisons? Thanks.
 
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With the Prius there is a technique where the accelerator is pushed only slightly, resulting in the IC engine staying off and the car running on electric only. It's also possible to install a switch to turn off the IC when desired.

Although the capacity of the Prius batteries is small, very good efficiencies are attainable by using the electric only for acceleration, and the IC for cruising (where it'll run at a constant maximally efficient RPM).

My father did a home-brew EV conversion of a 1970 Citroen a few years back (a great car). He installed a small IC generator in the engine compartment which would top up the batteries for longer trips - it added about 15% to the range.

He started with lead-acid batteries but he recently bought a pack of lithium-ion for his Scion xB conversion, which will get double the range (100 miles) at half the weight.
 
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Should have said, in the Prius and similar vehicles at the moment I believe electric only will only get you to about 25-30mph, the electric motor isn't big enough for more (without wind/down hill etc)

KENAT, probably the least qualified checker you'll ever meet...
 
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For short range cars battery technology is most easy. The only power source that I see after coal is outlawed (global warming) and natural gas runs out (nuke is already unpopular) is wind.
Prices are coming down and the only real problem is transmission. Long haul transmission can overcome local calm problems. Photovoltaic is too expensive. The available wind energy in the US far exceeds its energy needs.
Pumping energy into a car with magnetic fielsd might be easier than sliding contacts, if it comes to that. I already verified that it would be force free.

My friends are building battery powered cars and my next will be electric.
Has anyone made the riders pedal yet?
 
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The Prius does modulate its engine speed so that for a given power output it always operates at its most efficient throttle opening. At any power output above idle its efficiency is greater than 30%, on this operating curve.

It does this by being able to run at /any/ effective gear ratio, and using the battery as a buffer so that the engine can always sit on this operating curve.





Cheers

Greg Locock

SIG:please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
 
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That is the same point I raised a couple of weeks ago. Water use/waste is a really big and growing issue. I worked on a project a few years ago to try to bring Oil & Gas produced water to a power plant to reduce their use of potable water. The project looked good, but our short sighted legislators looked out their windows and saw it clouding up and killed the project.

To say that this country's energy policy is short sighted is like saying that the universe is kind of big.

David
 
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From article:
Designers envision something called a personal rapid transit (PRT) system. "Really, all it is is a car," says Scott McGuigan of CH2M Hill, the construction firm that's building Masdar City. "It's a simple vehicle [for] six passengers. It's designed like a car, but obviously it's powered by solar energy with batteries."

These solar-powered cars would run under the city like a subway system. But McGuigan says the cars wouldn't run on fixed routes. Basically, they'dl take you anywhere you wanted to go. McGuigan says PRTs represent an energy-efficient way of moving people among roughly 1,500 stations.

"Art without engineering is dreaming; Engineering without art is calculating."

Have you read faq731-376 to make the best use of Eng-Tips Forums?
 
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I hope the Masdar City project is successful. Oil wealth and energy has allowed population levels in the middle east to balloon to unprecedented levels (in one of the harshest environments on this planet), but sooner or later oil production will dwindle and they'll find it impossible to sustain their recently modernized civilization. Hopefully more middle eastern leaders will recognize the seriousness of their situation and come up with plans for a post-oil transition.
 
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Some communities have electric buses.
The UK had electric milk floats for decades which suggests that goods ought to be received in some peripheral transit area and carried into the community, to shops, factories etc by electric powered vehicles.

But the problem is the batteries. They are expensive, add weight and are themselves a major "end-of-life" problem.
The alternatives are electric trams, trolley buses etc.
Indeed, having pulled up all the tracks and overhead power lines for trams they are now being re-introduced in many cities. They are clean quite and efficient.

However, to be of real value I think some similar approach is needed for the car. Most people drive on paved roads almost all of the time.
If the major routes were provided with some form of power grid then hybrid cars could transition from petrol/diesel to electric and not have to carry batteries. If an all electric car was proposed then it would need small batteries to transition it from minor roads to major and from the driveway to the roads. Once on the gridded roads it could re-charge its batteries on the move. I would think that could significantly reduce the necessary battery size, weight and cost and perhaps avoid the need for special steels in the car construction and maybe extend battery life.

Think dodgem cars or think full scale Scalextrics (slot racers) and consider that anything that threatens to electrocute jay-walkers would have to be a good idea. Cyclists too, especially express messenger cyclists.

Bring back the C5 for pedestrian areas and city centres?

JMW
 
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Possibly a high current wire with an AC signal could be buried in the center of a lane, and a secondary winding could both power and guide the vehicle - off track, lose your power or set off a buzzer or turn off cruise control or something like that. Too many drivers would probably fall asleep though - forget the "guide" idea...
 
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Will the US electric grid support the added load of electrified transport? Recent deregulation of the power industry has left the transmission infrastructure starved for investment. Brownouts and blackouts may occur more often even without electric vehicles.


If solar becomes cheaper a personal solar charging station would become feasible.
 
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Maybe they could use the in-road power system as a transmission line too...
 
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Can't believe I forgot to repeat myself. A while back (year or two?) similar discussion came up in another thread.

One idea I had is to make exchangeable battery packs. Perhaps on the underside of the vehicle. Drive to a 'battery' station, pull over a pit (with guides/cover etc. so you don't drive into the pit!). A robot exchanges the battery pack for a fully charged one. You get charged for the electrical energy in the pack. The station recharges the packs....

KENAT, probably the least qualified checker you'll ever meet...
 
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KENAT, Got a patient on that idea?

...Seriously, awsome idea
 
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I'm very patient.;-)

Oh you mean Patent. No, maybe I should but it's in the open now and can't be patented if I recall correctly.

Maybe I could sell it to my brother in law, he works in the electric industry. Then again his company wasn't fussed by my idea of integrated off shore power plants.

KENAT, probably the least qualified checker you'll ever meet...
 
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Apparantly I'm a bit late again, darn. If only I'd had this idea back when I was a teenager!


If there was an exchangeable battery, an infrastructure of relatively ubiquitous charge spots and battery exchange stations, and a mobile operator that would own and operate the infrastructure as well as all of the batteries -- and if I could subscribe to this operator for miles, just as I now subscribe to AT&T for minutes -- under those circumstances I would love to own an electric car!
— Mike G., Tenafly, NJ
Click to expand...
from






KENAT, probably the least qualified checker you'll ever meet...
 
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If I recall GM tried the pilot wire in the road idea, or more correctly magnets embedded in the road. (Now where did that disappear to)?

As far as power distribution over the power network, I recall that there is plenty of capacity for at least 8 to 12 hours a day (more correctly at night. Which happens to be the same time most of the wind power happens here.

Solar works fine until a nice hail storm. I guess you can park your car under something (can't get much sun that way).

The elecrtic industry is capacity limited by goverment regulations, but get rid of those and the capacity will show up.

How about parking meters attached to power outlets?
 
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What does a block heater have to do with electric cars?

Unless you are talking about the block design of most batteries.

 
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