Prius seldom runs on batteries alone?

That would go partway to explaining why a US Prius gets better mileage
than a UK Prius. Although I can't find the exact size, Turanza have
significantly higher rolling resistance than Goodyear Integrity tires.
Also the 195 versus 185 width increases aerodynamic drag.

http://onlinepubs.trb.org/onlinepubs/sr/SR286Rolling_Resistance_Data.pdf

 

You know, these are topics that have been well talked through in
the not-so-distant past. Google would be your friend.

But: petrol engine's efficiency (Atkinson Cycle IIRC: less power
developed for same displacement as commonplace Otto Cycle engine
yet much better use of fuel) and general engineering qualities.

The notorious electrical bits allow some of the others. A Prius
doesn't break down easily into "this only does that". Parts are
idiosyncratic for more than one reason, often as not.

Day-to-day: engine properly warmed; tyres at right pressure; how
it is driven and maintained; type of fuel.

 

For the sake of the experimental data, I have just been outside
to check my 2005 UK Prius: out in the dark dank chill with just
my feeble torch for company, as winds moaned and owls hooted...

Bridgestone Turanza. Couldn't make out the associated numbers.
But the tyres fit fine.

I hope you lot appreciate that this effort was above and beyond
the call of any duty. Where do I apply for my medals?

BTW, why don't they fit Integras in this market? Mine was made
in *.jp, so they can't be any harder to find. Conflicting road
demands and/or national car type certification conditions?

 

It was an AT Tercel...

 

I was reading it off the computer...

 

Whew...I was...it was colder today!

 

Reducing the amount of time the engine runs at very low efficiency is the
big one. As the topic illustrates, the present Toyota system isn't very
aggresive at that but it still shuts the engine down and uses electrics
enough of the time to avoid wasting about half the gasoline in low speed
use.

With more powerful electrics (and especially if it becomes practical to
include battery power that will carry a car at full load over major mountain
ranges) the engine can also be downsized. Accelerator response and passing
are the rightful domain of electric power, rather than increasing engine
power and thus reducing efficiency even more in normal use; that darned
Second Law of Thermodynamics again.

Mike

 

We will award you the Parliamentary medal of freedom (all rubber).

The Turanza has better resistance to hydroplaning and longer tread life.
Here are the Consumer Reports ratings of it:

Braking - good
Cornering - poor
Emergency handling - good
With ABS - good
Hydroplaning - good
Snow traction - poor
Ice braking - poor
Steering feel - good
Impact - fair
Noise - fair
Rolling resistance - poor
Tread wear - very good

 

I recommend just using the brakes - they don't normally use friction above
12 mph or so. The brakes on my 106K mile Prius are nearly at original
thickness.

"B" mode is somewhat less efficient than using the brakes, because it
reduces regeneration. That doesn't make a huge difference, but just braking
is easier, too. "B" mode is useful on long downhills, especially if the drop
is more than 2000 ft. When the battery is fully charged the friction brakes
start getting wear.

Mike

 

Okay, so long as it doesn't bounce. (OT: OTOH, if Parliament is
involved, some kind of dodginess seems likely.)

Hmm, yes. It does rain occasionally in the UK, more than in the
sunny parts of *.ca.us at least. And snow has been short lately.

Ta. I shall luxuriate in that low wear and loss of hydroplaning,
while maintaining the proper tyre pressures.

 

Please advise us how these grossly inefficient vehicles get this kind
of mileage:

http://www.greenhybrid.com/compare/mileage/

 

Mike,

This is going to be my last on this subject. I'm not going to
convince you and you're not going to convince me.

You don't point to any hard info on increased efficiency, you just say
it is so. I have read where some of the Toyota and Honda hybrid
customers are not happy. They are not getting the mileage the sicker
says they should. They aren't missing the figure by 4 or 5%, they're
missing it by 25 to 30%. They have gotten some lawyer to file a class
action suit. No great challenge that and filing a law suit doesn't
prove anything, I grant you. But it does show that not everyone is
tickled pink with their hybrid.

I own a 2006 Corolla. It has a small IC engine and gets good mileage
while delivering reasonable performance, that's why I bought it. An
honest 35 to 37 mpg on the highway at 60 mph. Mileage around town is
less but still in the mid 20's. The reason why it gets better mileage
than my Mercury Grand Marquis is because it's small and light and
doesn't have as much engine. Two of the Toyota engines still wouldn't
make the V8 that is in my Merc.

The Merc gets around 28 to 29 mpg at 60 mph but only about 15 to 17
mpg around town. The Merc has 2 major things working against it on
mileage, weight and air resistance. It's about as stream-lined as a
book case and weighs almost as much as 2 Corolla's.

What I'm trying to point out is that I could never get the Mercury to
get the same mileage as the Corolla. If I put the engine and drive
train from my Corolla into my Mercury, it wouldn't get anywhere near
the mileage of the Corolla. But the performance would be a lot worse
than either of them furnish now. Adding an electric motor, batteries
and the control circuitry of a hybrid to the existing drive train of
the Mercury would only further decrease the mileage.

I also will never get the Corolla to be as comfortable as the Mercury.
I can drive the Grand Marquis for hours without getting tired but the
Corolla has me squirming around in less than an hour.

You mentioned that you decided while you were still in high school
that automobiles were inefficient and I agree. But adding more
inefficient elements to the mix won't make for greater efficiency.

I could be a smart a-- here and say that some folks believe in Global
Warming, that CFC's cause the Ozone hole over the South Pole, the
Easter bunny and Santa Claus....but I won't. hehehe

I think I'll go mix some aged ethanol from Tennessee with water and
ice now. I've enjoyed the discussion but I'm not going to respond to
anything else on the subject.

Thanks
Jack

 

It is my belief that you are misrepresenting what I said, taken out of
context. I will try it this way: I generate a certain amount of energy
stored in the batteries, and only use less of that than I would like.
Tomes

 

I wish it had tires of low rolling resistance. The ones on there are only
normal rolling resistance.
Tomes (otherwise generally agreeing here)

 

That's another thing. The minimum speed thing on CC. Why not let it
start at 10 MPH or so? I use it a lot when the speed limit is, say,
40MPH. It prevents me from accidentally going faster, which I can so
easily do. But I cannot use it for a speed limit of 30, which we have
around here on windy rural back roads. I would really like to set it at
33 and just let it go, but alas I cannot. I perceive this as another
flaw. (The Jeep is the same way, engages at about 35).
Tomes

 

I was just out there too putting some more air into the Prius' tires (in
response to a RayO post that spurred me on), and saw that the Integras
were "Made in Japan", stamped right on the tire sidewall. If the car came
from Japan (which I believe they all do), they made a conscious choice to
fit yours with the Bridgestones instead of the Goodyears.
Tomes

 

Now that is a website I had not found yet. I will go back to that for a
read, but now right now (bookmarked). Thanks plenty.

My point is just a little bit off from what you are saying (and thanks for
saying it). My angle is that I would like the Prius to use the electric
motor moreso than it does now. I believe that I generate enough that it
ought to do that.
Tomes

 

OK, I know I have read this, and what I have read has not always been the
same thing. In your words, what exactly does 'B' mode do and how?
Thanks.
Tomes

 

IIRC, the minimum speed to set cruise control on a Toyota is around 25 MPH,
below which, the CC will not set and the memory clears. I can set the CC on
our 3 Toyotas at 30 MPH, which I do in areas where the police often sit ;-)

 

According to the faq section at www.toyota.com:
"B" is the position for engine braking. Engine braking assists the brakes
in slowing the vehicle. It serves a similar function to downshifting on an
automatic transmission. This position is intended for going down long
declines, and utilizes the electric motor to slow the vehicle and regenerate
electricity. For more information please reference Section 2 of your
Owner's Manual.