Why Electric Motors Are 3X - 4X More Efficient Than Internal Combustion

ence

claims the theoritical specific energy [for work] of Li - Air is 11kW-hr/kg -- 3X that of liquid fuel.

Bret Cahill

inefficiency.

Should one laugh or cry ?

Graham

Some gutless f****it desperately cowering behind Eeyore wrote just the pathetic excuse for a juvenile troll thats all it can ever manage.

That's not what the studies say. Daniel posted a few results in a side thread.

Rob

I agree. I think that there will be great advances (albeit slowly) in battery tech the future, but even so, I don't think that battery technology is the major limiting factor at this point. What is lacking is a automotive 'platform' that allows batteries to drive vehicles.

Currently, even if you would have the ideal battery around, there is nothing you can do with it (other than rebuilding your vehicle completely). That is because all vehicles sold today the ICE drives wheels directly (via the drive train). Hybrids (like the Prius) are 'parallel' hybrids, which add a (not so strong) electric motor/generator and add a (not so large) battery. That helps a little bit in fuel efficiency (partial regenerative braking mostly) but it also makes the overall system more expensive. If you enlarge the battery (for plug-in), you are not adding much value to the vehicle, since the electric motors are a (power) limiting factor in parallel hybrids (they are not strong enough for normal operation, including normal accelleration and freeway cruising.

I think we need 'series' hybrids before the role of batteries becomes important. In series hybrids, electric motors drive the wheels, and the ICE is reduced to a secondary role (auxiliry power unit). The ICE is much smaller there, and runs much more efficient, and also the stronger electric motor/generators can take more advantage of regenberative braking. This not only makes series hybrids up to a factor 2 better (more efficienct) than even parallel hybrids, it also creates a 'platform' for plug-in and even all-electric drive.

For example, if most cars on the road would be series hybrids, then I could imagine a very inexpensive plug-in or all-EV conversion kits (consisting essentially only of a battery), and this would immediately increase the (electric) driving range, and NOT compromise on power. This series hybrid as a platform for automotive design would allow easy 'retrofitting' of batteries on existing vehicles if liquid fuel again becomes more expensive than electricity or when batteries become better or cheaper than today.

Currently, the decision between battery or gasoline cannot be taken by the car owners, because retrofitting batteries is not an option. With series hybrids on the road, even if battery technology would not advance that much, the 'market' (not discussions in this NG :o) could decide if battery technology is advanced enough or not.

My 2 cts. Rob

All batteries have a 'theoretical' upper energy density limit, which is rather easily calculated (at least if you are an electro chemist). Currently, most batteries operate far from this theoretical upper limit (often a factor 10 off what is possible).

I actually am looking for scientific papers that explain why they are so far off their theoretical limit, and how to improve on that.

All IC engines are inherently dirty and the smaller they are the dirtier they get on a per horse power basis.

Adiabatic wants a big volume/surface area which means a big engine.

Bret Cahill

future,

And why do you think that when the lead acid cell has barely changed in around

100+ years.

Graham

to

I wonder if you even read the rest of Daniel's post (after you noticed the letters CO2 reduction in the first lines). Hint : ALL pollutants are down when we use grid electricity to drive vehicles.

isolation

That's right. CO2 is not the cause of climate change. Pirates are, as this graph proves :

Rob

future,

100+ years.

and will not for the next hundred. Just like the vacuum tube and the incandecent light bulb hardly changed over the past hundred years.

I haven't seen the studies. But pollution from coal plants is currently a serious problem. Pollution from modern cars really isn't.

CO2 is not a pollutant.

John

to

letters CO2 reduction in the first lines).

Sure. Light, aerodynamic vehicles that don't go very far will in fact reduce pollution.

John

large

from

minimum.

Do you have data to support that statement ?

That's not what the supreme court says :

from

vehicles

news

on ALL

be best to

the letters CO2 reduction in the first lines).

vehicles.

Right, but that's not what was stated in the studies.

What was stated is that vehicles driven from grid electricity pollute significantly less that similar vehicles driven from gasoline or diesel.

Unscrubbed smokestacks most certainly are a problem.

Indeed. The last 'MOT' test my Saab had showed something like 0.0000% (or whatever they measure it in) hydrocarbons output, negligible CO in the single digits IIRC ppm and lambda=1.

It is a vital constituent of life.

Graham

Then they're BARKING MAD.

Graham

When you do a 'total environmental impact' analysis I very much doubt that actually unless the electricity is all coming from nukes.

Graham

So what's causing the climate change? We see that the sunspot correlation is crapola. Is the climate changing and the north pole melting because we fart too much? Are you seeing something in coal that you do not see in auto exhausts and can you formulate a correlation?

--
"I know no safe depository of the ultimate powers
of society but the people themselves; and
if we think them not enlightened enough to
exercise their control with a wholesome
discretion, the remedy is not to take it from
them, but to inform their discretion by
education." - Thomas Jefferson
http://GreaterVoice.org/extend

Natural variation.

Yes, but the total sun output correlation aint.

Nope, there isnt any evidence for any more than natural variation.

The conditions in greenland were actually quite a bit warmer than they currently are in medieval times, before we increased the atmospheric CO2 levels.

Yes, the emissions from power stations are quite different to car exhausts.

Nope. And we dont need one, natural variation has clearly been more than we are currently seeing.