[Jim Thompson]

Also, it isn't like 10 million cars will suddenly appear overnight, they
would be added over a period of many years. During this transition,
power companies will slowly be building up the grid, esp. in areas that
have more electric vehicles...

Charlie

Just think of the litter, cars with dead batteries stalled on the
freeway, and no where to plug them in ;-)

...Jim Thompson

 

[MooseFET]

I don't ever recall saying "more-efficient-at-higher-speed".

But I guess it WOULD depend on your definition. The engine is
optimized right around 3000RPM (85MPH), but external drag is higher.

If you shift to a lower gear, 3000 RPM is at a lower speed. If there
isn't an issue that is well modeled by a fuel leak, the milage would
improve.

 

[MooseFET]

"Remove excess weight"... don't give a leftist weenie a ride ;-)

At those speeds it is drag not weight that matters. You shouldn't
wear a dress while driving.

 

[krw]

If you shift to a lower gear, 3000 RPM is at a lower speed. If there
isn't an issue that is well modeled by a fuel leak, the milage would
improve.

Ever consider that transmissions aren't equally efficient in all
gears and perhaps the over-drive locked-up may be a tad more
efficient than the lower gears? There is also work done just
spinning the engine. Me thinks you're wrong.

 

[John Larkin]

At those speeds it is drag not weight that matters. You shouldn't
wear a dress while driving.

You get the best mileage if you wear nothing at all.

John

 

[JosephKK]

MooseFET [email protected] posted to sci.electronics.design:

It also won't be much over about 50MPH. It takes about 15 HP to
push
a modest sized car at 50MPH. The windage losses per mile run as
just about the square of the speed.

Not necessarily. My first new car got about 22 mpg at 55 mph and
about 26 mpg at 70 mph. Back then i had plenty of documentation to
back it up. Kinda funny, 70 mph occurred right the rmp torque
peak. It couldn't be a coincidence could it?

 

[JosephKK]

MooseFET [email protected] posted to sci.electronics.design:

At those speeds it is drag not weight that matters. You shouldn't
wear a dress while driving.

But my favorite gal likes wearing dresses. Oh wait, that wouldn't
be drag then. I guess i will have to tell her not to wear pants.

 

[Spehro Pefhany]

You get the best mileage if you wear nothing at all.

I suspect Spandex is better than nothing. More slippery than hairy
surfaces and it could prevent the energy-sapping oscillation of fatty
and/or dangly bits.

John

Interesting that modern hybrids apparently get better gas milage in
city driving rather than highway.

Eg. Prius 60mpg city, 51mpg highway

http://www.toyota.com/prius/specs.html


Best regards,
Spehro Pefhany

 

[Eeyore]

Just think of the litter, cars with dead batteries stalled on the
freeway, and no where to plug them in ;-)

Hybrids will never be stalled anywhere unless their fuel tanks run dry.

Graham

 

[Spehro Pefhany]

Well, I suppose some people are more viscous than others.



We have a friend who bought a Toyota hybrid. But hauling all those
batteries up and down the hills here apparently isn't efficient... her
mileage is mediocre.

The battery pack is actually pretty tiny on the Prius (40kg) 6.5AH at
273VDC, which works out to 3% of the curb weight.

http://www.nrel.gov/vehiclesandfuels/energystorage/pdfs/2a_2002_01_1962.pdf

People don't buy Prius' to save gas, they buy them to be hip and
stylish. So instead of smog, we have clouds of smug.

John

Yes. _South Park_ dubbed it the "Toyota Pius". My calculations
indicate the payback to be marginal on hybrids, even with a $4K
government subsidy, so long as gas remains around $3US/US gallon, and
the Prius yields significantly better mileage than, say, the hybrid
Camry.

Best regards,
Spehro Pefhany

 

[MooseFET]

MooseFET [email protected] posted to sci.electronics.design:





Not necessarily. My first new car got about 22 mpg at 55 mph and
about 26 mpg at 70 mph. Back then i had plenty of documentation to
back it up. Kinda funny, 70 mph occurred right the rmp torque
peak. It couldn't be a coincidence could it?

It was likely a combination of coincidence and something very wrong
with the car. 22MPG at 55MPH is a horrid milage. This is very like
the leaky fuel line case.

 

[MooseFET]

I suspect Spandex is better than nothing. More slippery than hairy
surfaces and it could prevent the energy-sapping oscillation of fatty
and/or dangly bits.


Interesting that modern hybrids apparently get better gas milage in
city driving rather than highway.

Eg. Prius 60mpg city, 51mpg highway

http://www.toyota.com/prius/specs.html

This is as you would expect if they are making good use of the energy
in the fuel.

 

[AZ Nomad]

Don't give me your problems! Give me your solutions!! What's the
answer when the oil runs out?

Where do you think the electricity comes from? An electricity well?

 

[MooseFET]

Ever consider that transmissions aren't equally efficient in all
gears

Yes but he didn't report he was driving with a faulty one.

and perhaps the over-drive locked-up may be a tad more
efficient than the lower gears?

A tad but not enough to make the difference. The energy per mile
increases as the square of the speed.

There is also work done just
spinning the engine. Me thinks you're wrong.

I think not.

 

[Spehro Pefhany]

This is as you would expect if they are making good use of the energy
in the fuel.

Sure. It's interesting to see that they've actually achieved it, with
significant mileage improvment to boot, in a practical production car.

Best regards,
Spehro Pefhany

 

[René]

This is as you would expect if they are making good use of the energy
in the fuel.

Marketing figures...."Top Gear" (GB car TV show) registered a Prius
not doing better than 45 miles / gallon.

In Europe, popular diesel cars easily beat that with simple,
non-hybrid engines.

 

[Spehro Pefhany]

Marketing figures...."Top Gear" (GB car TV show) registered a Prius
not doing better than 45 miles / gallon.

I believe they are test figures done with US government (EPA) approved
test procedures, so while you may not achieve those figures in
practice they should compare fairly well.

In Europe, popular diesel cars easily beat that with simple,
non-hybrid engines.

Size-wise, the Prius is at the low end of what is practical for North
American realities. Something the size of a Smart Car is practical for
very, very few people here. Most of them that I see are either moving
advertising billboards for businesses or second cars for DINK smug
urbanites.

Best regards,
Spehro Pefhany

 

[John Larkin]

Yes. _South Park_ dubbed it the "Toyota Pius". My calculations
indicate the payback to be marginal on hybrids, even with a $4K
government subsidy, so long as gas remains around $3US/US gallon, and
the Prius yields significantly better mileage than, say, the hybrid
Camry.

Both hybrids would get far better mileage if the batteries, the
electrics, and all the fancy controls were dumped. What's left would
be a small, light, slippery, ugly car with a small engine. All you'd
give up is acceleration and the questionable advantage of regenerative
braking, a small price to pay for dumping the batteries.

John

 

[René]

Size-wise, the Prius is at the low end of what is practical for North
American realities. Something the size of a Smart Car is practical for
very, very few people here. Most of them that I see are either moving
advertising billboards for businesses or second cars for DINK smug
urbanites.

E.g. a mediocre Golf diesel will hold as much people/ luggage as a
Prius, has comparable mileage, is better made, way cheaper. It's a
mid-sized family car. There are more like those.

I guess diesel is not really happening overthere?

A Smart is a fashion accessory. Priusses (Priae?) are for movie stars
that want to act green in the public eye. (and drive V8 Mustangs for
fun usually

 

[John Larkin]

Yes but he didn't report he was driving with a faulty one.


A tad but not enough to make the difference. The energy per mile
increases as the square of the speed.

Not in this graph:

http://www.fueleconomy.gov/feg/driveHabits.shtml

I've seen a few other mpg-vs-speed curves, and they all look similar.
Looks like aerodynamic drag starts to seriously kick in above 55 MPH.

John