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-   -   Prius seldom runs on batteries alone? (https://www.gtcarz.com/honda-mailing-list-327/prius-seldom-runs-batteries-alone-297476/)

Gordon McGrew 02-18-2007 12:40 PM

Re: What about the mileage!?!?!?!?!
 
On Sun, 18 Feb 2007 10:50:42 -0500, You guess
<jackj^remove^180@adelphia.net> wrote:

>On Sun, 18 Feb 2007 07:14:04 -0700, "Michael Pardee"
><michaeltnull@cybertrails.com> wrote:
>
>>"You guess" <jackj^remove^180@adelphia.net> wrote in message
>>news:37gft253roh0tm5d721o4ebdb9ikh0a81r@4ax.com. ..
>>>
>>> Stop and think about hybrids, what they are and how they work. Hybrids
>>> are nothing new, the railroads have been using them for since the
>>> 1940's. Almost all freight trains are pulled by diesel-electric
>>> locomotives. They use diesel-electric for one reason only. A pure
>>> diesel locomotive would require a clutch that you couldn't believe. It
>>> would have to slip for 10 minutes or more while the train was brought
>>> up to speed while transferring as much as 2,000 horse power to the
>>> traction wheels through a 50 speed transmission. The electrics take
>>> the place of this 40 foot diameter, electric fan cooled, multi-plate
>>> wet-clutch as well as the mechanical drive lines.
>>>

>>You are right about the way locomotives operate and why they are
>>diesel-electric (as are many truly huge machines). But you are mistaken to
>>call them hybrids - they have only one power source, the diesel engine. They
>>just have electric transmissions.

>
>Okay if you don't want to call a diesel-electric locomotive a hybrid,
>that's fine with me. But you shouldn't call hybrid cars hybrids
>either. They get all of their energy from their IC engine also. The
>only difference is that hybrid cars also have a mechanical drive train
>along with their electrical one.
>>
>>Hybrids today get their main efficiency improvement from not using the
>>engine as much to do ludicrously inefficient work. As the OP noted, the
>>engine is still used at times that don't make a lot of sense. Blame that on
>>the infancy of the technology.

>
>No, it uses the IC engine more. The IC engine powers the car at all
>times, even when it isn't running. If the IC engine isn't running,
>the car is using energy produced by the IC engine at some time in the
>past and stored in the batteries.
>>
>>> Your hybrid car is a political solution to a political problem. Your
>>> car has to haul around heavy batteries, a big generator to recharge
>>> the batteries and all the electronics needed to control the electric
>>> motor, the charge going into the batteries and monitoring the
>>> condition of the batteries. Plus it STILL has a gas IC engine and
>>> fuel tank to haul around.
>>>

>>
>>Actually, it is an engineering solution to a fundamental conceptual problem.
>>Even as a teenager learning about cars I was struck by the horrible
>>inefficiencies of using large engines to put out negligible power for nearly
>>the entire range of the car's operation. But it was the '60s and gas was
>>cheap. When I first heard about hybrid power trains (around 20 years ago) I
>>immediately recognized them as the solution to the century-old problem.
>>
>>>
>>> There is no way it can get the same over-all mileage and still have
>>> the same performance as a gasoline-only car.
>>>

>>
>>Ah - that's where you are 100% wrong. One of the central characteristics of
>>hybridization is that the acceleration performance is independent of the
>>power plant capacity, just as a conventional power train's performance is
>>independent of fuel tank size. The engine can be off or just plain dead
>>without affecting the immediate performance of a serial hybrid (none in
>>production yet, sadly). A serial hybrid is essentially an electric car with
>>a charging system on-board. Right now the technology exists to build a
>>serial hybrid that will give the hottest conventional power trains a run for
>>their money; a Tesla (http://tinyurl.com/n52mh) with a small generator
>>tucked somewhere would qualify. Honda (http://tinyurl.com/y96x8o) and Toyota
>>(http://tinyurl.com/2w379) have both demonstrated concept cars that clearly
>>fall in the high performance range and deliver fuel economy in the miser
>>range - 400 hp and an estimated 40 mpg for the parallel hybrid Honda and 400
>>hp and 32 mpg for the series-parallel hybrid Toyota. Honda engineers pointed
>>out in the Popular Mechanics article back then that using electrics for
>>torque provides off-the-line acceleration equivalent to a 600 hp
>>conventional power train. Toyota simply mentions 0-60 mph in 4 seconds.

>
>You're confusing acceleration performance with efficiency.
>>
>>Mike
>>

>Mike, you can't ignore physics. It takes energy to accelerate mass.
>Increase the mass and you have to increase the energy input to
>maintain the same performance level. That's why all economy cars are
>small and light. More mass also equals higher rolling resistance
>which requires energy to overcome.
>
>You can use a battery and electric motor to increase the acceleration
>performance of a car with a small IC engine but you will have to put
>back the energy you have used at sometime in the future. Each time
>you convert from one form of energy to another, you will have losses
>which can't be overcome. You start out with the chemical energy
>contained in a gallon of gas. Then you burn that gas to produce heat
>energy but you can't capture all of the heat. You convert that heat
>energy into mechanical energy with an IC engine which has internal
>friction losses. Both hybrids and conventional cars have these same
>losses. To this, a hybrid car adds changing that mechanical energy
>into electrical energy using an alternator, friction losses and heat
>losses. You use that electrical energy to recharge a battery
>converting electrical energy back into chemical energy with it's
>associated losses. Then, at some time in the future, you discharge
>that battery converting its chemical energy back into electrical
>energy with more losses and that electrical energy back into
>mechanical energy with even more losses.


But you are neglecting the factors which make hybrids more efficient:

The electrical system provides a means of recovering kinetic energy
during braking. The energy which would have gone into heating the
brake rotors (and wearing out the pads) is converted to energy stored
in the battery. Virtually all of the battery charge comes from this
source. Even 50% efficiency in recovery of energy which would have
been wasted is efficient.

The availability of energy stored in the battery means that the engine
doesn't have to provide all the energy under conditions of maximum
demand. This allows the engine power to be down rated and therefore
run at more efficient (higher) power levels more of the time, e.g.
cruising.

The availability of electric drive allows the engine to be shut down
at times when it is least efficient, e.g. idle and low speed
operation.

But don't try to factor all this together, just look at it as a black
box. You put gas in and go farther and/or faster than in a comparable
non-hybrid car. What more evidence do you want?

>There ain't no such thing as a free lunch. Perpitual motion is a
>thing of fiction. If you believe all of these conversion losses add
>up to an increase in efficiency then you might want to buy this
>ethanol plant I have for sale.


If it is in Scotland and they are aging it for at least 12 years, let
me know.

You act like hybrids are hydrogen fuel cells. People are driving
hybrids now and getting far better mileage than with conventional
cars. It is a proven, practical technology. Using your reasoning, a
Prius should be getting 16mpg and no one would be selling them, let
alone buying them.

>Don't get me wrong, I like ethanol. When its aged in charred oak
>barrels for 10 years or so and then mixed with a little water. But
>burn it for fuel....man, that's just plain wrong.


But they make it with corn. If they were making it with barley, you
would have a point. ;-]



mrv@kluge.net 02-18-2007 12:53 PM

Re: What about the mileage!?!?!?!?!
 
> The funny thing is, the average American Prius driver drives the damn car
> like a silver-haired Granny in the 1964 F-85 she bought brand new 43 years
> ago. So adding the EV mode would be a good idea on Toyota's part. In the
> week I drove one, I spent some time crawling from a start, and found it
> did NOTHING! I was getting better mileage with an AT Tercel. When I
> started driving it 'normal', the numbers didn't budge.


Yes, and you've already said that that was on a pre-production model
in 2000. The car has had numerous changes since then! I suggest that
you try another week test drive in a current NHW20 Prius.

(There's also far better emissions controls (notorious for lowering
fuel economy) since your AT Tercel... and I won't get into the apples
and oranges of comparing a manual to an automatic CVT...)


mrv@kluge.net 02-18-2007 01:04 PM

Re: Prius seldom runs on batteries alone?
 
On Feb 17, 2:57 pm, Bill Tuthill <ccree...@yahoo.com> wrote:
> In alt.autos.toyota Andrew Stephenson <a...@deltrak.demon.co.uk> wrote:
> What size tyres do you have mounted on that Prius, and what brand?
> And do they really still sell gasoline in the U.K. by the imperial
> gallon and not by the liter, or I suppose you would spell it litre
> or some modern French- or Continental-based measurement of volume?


2004-2007 UK tire
Bridgestone Turanza ER30
195/55R16
87V

(Note the different size than the US!)

UK and Canada uses MPG using imperial gallons. Canada and most
everywhere else use l/100km. Japan still uses km/l.


Andrew Stephenson 02-18-2007 01:05 PM

Re: What about the mileage!?!?!?!?!
 
In article <rh2ht29qdd7068bbkge1qgvb7v9r0sc28d@4ax.com>
RgEmMcOgVrEew@mindspring.com "Gordon McGrew" writes:

> [...]
>
> But you are neglecting the factors which make hybrids more
> efficient:
>
> The electrical system provides a means of recovering kinetic
> energy during braking. The energy which would have gone into
> heating the brake rotors (and wearing out the pads) is
> converted to energy stored in the battery. [...]


Most anti-hybrid kooks are narrowband thinkers. They don't like
to see the world as a web of influences. A simple straight line
is about as complex as they can handle. For example, your point
about the regeneration system sparing the vehicle's brakes ought
to suggest to them another indirect saving: less wear on brakes;
longer intervals between replacements; less use of materials and
energy in their manufacture/replacement; and lower bills. Yet I
live in hope that it'll click for them, one day.
--
Andrew Stephenson


mrv@kluge.net 02-18-2007 01:40 PM

Re: Prius seldom runs on batteries alone?
 
On Feb 16, 10:14 am, "Tomes" <a...@here.net> wrote:

> It is my unscientific belief that I regenerate more than I use, based upon
> my observation that I am in the green a lot and hardly ever go below half
> of the blue. Thus, I would like to use the electric moreso that it does
> by default.


You can view the NHW20 Prius battery charge levels at:
http://privatenrg.com/#Full_SOC

You'd know if you regenerated too much energy by your Prius trying to
get rid of extra charge. People who have just come down a long
downhill (mountain) often report that at a stop their engine will
cycle on/off repeatedly. The Prius will try to bleed off the high SOC
by having one of the electric motors repeatedly start and spin the
gasoline engine...

(Also, if the hybrid battery cannot accept any more charge, it simply
will not. You will no longer have regenerative braking, and will be
switched to a higher percentage of conventional hydrolic braking.)

If you are just driving around in the green and don't notice anything
else different, then you aren't regenerating more than you can use...


mark_digital© 02-18-2007 03:05 PM

Re: What about the mileage!?!?!?!?!
 

"Andrew Stephenson" <ames@deltrak.demon.co.uk> wrote in message
news:1171821912snz@deltrak.demon.co.uk...
> In article <rh2ht29qdd7068bbkge1qgvb7v9r0sc28d@4ax.com>
> RgEmMcOgVrEew@mindspring.com "Gordon McGrew" writes:
>
>> [...]
>>
>> But you are neglecting the factors which make hybrids more
>> efficient:
>>
>> The electrical system provides a means of recovering kinetic
>> energy during braking. The energy which would have gone into
>> heating the brake rotors (and wearing out the pads) is
>> converted to energy stored in the battery. [...]

>
> Most anti-hybrid kooks are narrowband thinkers. They don't like
> to see the world as a web of influences. A simple straight line
> is about as complex as they can handle. For example, your point
> about the regeneration system sparing the vehicle's brakes ought
> to suggest to them another indirect saving: less wear on brakes;
> longer intervals between replacements; less use of materials and
> energy in their manufacture/replacement; and lower bills. Yet I
> live in hope that it'll click for them, one day.
> --
> Andrew Stephenson
>


The engine isn't subjected to the strains of differing torque. The motor
handles that load quite nicely. Extra fuel usually needed (remember the
accelerator pump?) when lightly stepping up the speed is nicely handled by
the motor instead.

If someone wanted to get off the starting line as fast as I can they better
re-do their fuel economy calculations and stop lying through the teeth about
that one-time 36 mpg fillup. Man! You might think us hybrid owners just fell
off the alien turnip truck.
mark_



Michael Pardee 02-18-2007 04:23 PM

Re: What about the mileage!?!?!?!?!
 
"You guess" <jackj^remove^180@adelphia.net> wrote in message
news:1sogt2d22bgfhisiksaapvu88dnls9itro@4ax.com...
> On Sun, 18 Feb 2007 07:14:04 -0700, "Michael Pardee"
> <michaeltnull@cybertrails.com> wrote:
>
>>
>>Hybrids today get their main efficiency improvement from not using the
>>engine as much to do ludicrously inefficient work. As the OP noted, the
>>engine is still used at times that don't make a lot of sense. Blame that
>>on
>>the infancy of the technology.

>
> No, it uses the IC engine more. The IC engine powers the car at all
> times, even when it isn't running. If the IC engine isn't running,
> the car is using energy produced by the IC engine at some time in the
> past and stored in the batteries.
>>
>>> Your hybrid car is a political solution to a political problem. Your
>>> car has to haul around heavy batteries, a big generator to recharge
>>> the batteries and all the electronics needed to control the electric
>>> motor, the charge going into the batteries and monitoring the
>>> condition of the batteries. Plus it STILL has a gas IC engine and
>>> fuel tank to haul around.
>>>

>>
>>Actually, it is an engineering solution to a fundamental conceptual
>>problem.
>>Even as a teenager learning about cars I was struck by the horrible
>>inefficiencies of using large engines to put out negligible power for
>>nearly
>>the entire range of the car's operation. But it was the '60s and gas was
>>cheap. When I first heard about hybrid power trains (around 20 years ago)
>>I
>>immediately recognized them as the solution to the century-old problem.
>>
>>>
>>> There is no way it can get the same over-all mileage and still have
>>> the same performance as a gasoline-only car.
>>>

>>
>>Ah - that's where you are 100% wrong. One of the central characteristics
>>of
>>hybridization is that the acceleration performance is independent of the
>>power plant capacity, just as a conventional power train's performance is
>>independent of fuel tank size. The engine can be off or just plain dead
>>without affecting the immediate performance of a serial hybrid (none in
>>production yet, sadly). A serial hybrid is essentially an electric car
>>with
>>a charging system on-board. Right now the technology exists to build a
>>serial hybrid that will give the hottest conventional power trains a run
>>for
>>their money; a Tesla (http://tinyurl.com/n52mh) with a small generator
>>tucked somewhere would qualify. Honda (http://tinyurl.com/y96x8o) and
>>Toyota
>>(http://tinyurl.com/2w379) have both demonstrated concept cars that
>>clearly
>>fall in the high performance range and deliver fuel economy in the miser
>>range - 400 hp and an estimated 40 mpg for the parallel hybrid Honda and
>>400
>>hp and 32 mpg for the series-parallel hybrid Toyota. Honda engineers
>>pointed
>>out in the Popular Mechanics article back then that using electrics for
>>torque provides off-the-line acceleration equivalent to a 600 hp
>>conventional power train. Toyota simply mentions 0-60 mph in 4 seconds.

>
> You're confusing acceleration performance with efficiency.
>>


What I am pointing out is that efficiency has increased along with
performance - that is a basic characteristic of hybrid cars. Your premise
was that it couldn't be done.

>>

> Mike, you can't ignore physics. It takes energy to accelerate mass.
> Increase the mass and you have to increase the energy input to
> maintain the same performance level. That's why all economy cars are
> small and light. More mass also equals higher rolling resistance
> which requires energy to overcome.
>


If all we were doing was accelerating mass, there wouldn't be an issue. The
fallacy is that it takes some specific energy to accomplish the movement of
mass from one place to another, even if the height of the two points is the
same. That is not true at all; the efficiency of that operation is always
zero since the final potential energy is the same as the initial potential
energy. The question is how much energy is going to be wasted in the losses.

For the sake of argument we can keep the frictional losses the same, in
which case the question is in the efficiency of the motive source. That is
where conventional power trains are so dismal, running at a tiny fraction of
their full power output and suffering the staggering losses that go with it.
Hybrids make their biggest gains by using the power plant more efficiently.
Not that much more efficiently at this stage, but doubling the efficiency
from dismal to lousy is no big trick. There is something very wrong with
using a power train that is less efficient at 30 mph than at 60 mph.

The proof is in the actual performance - even hybrids such as the Prius
typically double the fuel economy of equivalent conventional cars in town.
On the highway, where the air resistance losses are dominant, the advantage
is much lower.

Mike



Bill Tuthill 02-18-2007 07:07 PM

Re: Prius seldom runs on batteries alone?
 
In alt.autos.toyota Michael Pardee <michaeltnull@cybertrails.com> wrote:
>
> There is a wide misconception that regeneration is a major source
> of the hybrid's efficiency advantage. In actuality, it is a very minor
> contributor.


What are the major contributors, then?

I'd have to assume shutting down the engine at stoplights helps a lot
for the EPA city mileage number.

Good aerodynamics and tires with low rolling resistance, certainly.

Thinking about it, regeneration might be minor, but not "very" minor.
What else could cause the jump from 30 to 50 MPG?


Bill Tuthill 02-18-2007 07:09 PM

Re: Prius seldom runs on batteries alone?
 
In alt.autos.toyota Chuck Olson <chuckolson01@removethiscomcast.net> wrote:
>
> As most have said, the battery has to be charged above a specific threshold
> for the ICE to turn off. I have found that you also need to be in cruise
> control. Normal driving with foot on the accelerator just doesn't produce
> electric-only operation except at very slow side-street speeds. I guess
> that's because the Prius computer doesn't trust human beings to drive at a
> single fixed speed. My favorite EV speed in cruise control is 34 MPH.


Interesting advice -- I'll have to try this.

> To make sure the battery is charged and ready for EV operation, you need to
> apply fairly heavy braking from freeway speed.. Just slowing down slowly
> doesn't charge up the battery very efficiently. Unfortunately this kind of
> driving is uncomfortable for passengers, so don't do it unless you're alone.
> Also, make sure you brake before you hit a curve or encounter cross traffic.


The B transmission setting is my favored way of doing this. I believe
it saves the brake pads, and it does not bother my passengers.


Bill Tuthill 02-18-2007 07:15 PM

Re: Prius seldom runs on batteries alone?
 
In alt.autos.toyota mrv@kluge.net <mrv@kluge.net> wrote:
>
> 2004-2007 UK tire
> Bridgestone Turanza ER30
> 195/55R16
> 87V


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...tance_Data.pdf


Andrew Stephenson 02-18-2007 07:18 PM

Re: Prius seldom runs on batteries alone?
 
In article <45d8ea26@news.meer.net> ccreekin@yahoo.com "Bill Tuthill" writes:

> In alt.autos.toyota Michael Pardee <michaeltnull@cybertrails.com> wrote:
> >
> > There is a wide misconception that regeneration is a major source
> > of the hybrid's efficiency advantage. In actuality, it is a very minor
> > contributor.

>
> What are the major contributors, then?
>
> [...]


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.
--
Andrew Stephenson


Andrew Stephenson 02-18-2007 07:37 PM

Re: Prius seldom runs on batteries alone?
 
In article <45d8ec13@news.meer.net> ccreekin@yahoo.com "Bill Tuthill" writes:

> In alt.autos.toyota mrv@kluge.net <mrv@kluge.net> wrote:
> >
> > 2004-2007 UK tire
> > Bridgestone Turanza ER30
> > 195/55R16
> > 87V

>
> 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. [...]


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?
--
Andrew Stephenson


Hachiroku $B%O%A%m%/(B 02-18-2007 08:08 PM

Re: What about the mileage!?!?!?!?!
 
On Sun, 18 Feb 2007 09:53:52 -0800, mrv@kluge.net wrote:

>> The funny thing is, the average American Prius driver drives the damn
>> car like a silver-haired Granny in the 1964 F-85 she bought brand new 43
>> years ago. So adding the EV mode would be a good idea on Toyota's part.
>> In the week I drove one, I spent some time crawling from a start, and
>> found it did NOTHING! I was getting better mileage with an AT Tercel.
>> When I started driving it 'normal', the numbers didn't budge.

>
> Yes, and you've already said that that was on a pre-production model in
> 2000. The car has had numerous changes since then! I suggest that you
> try another week test drive in a current NHW20 Prius.
>
> (There's also far better emissions controls (notorious for lowering fuel
> economy) since your AT Tercel... and I won't get into the apples and
> oranges of comparing a manual to an automatic CVT...)



It was an AT Tercel...

Hachiroku $B%O%A%m%/(B 02-18-2007 08:09 PM

Re: Re:What about the mileage!?!?!?!?!
 
On Sun, 18 Feb 2007 06:38:24 -0500, mark_digital© wrote:

>
> "Hachiroku ????" <Trueno@AE86.gts> wrote in message
> news:XDRBh.5880$am1.2065@trndny01...
>> On Sat, 17 Feb 2007 20:33:21 +0000, R PRINCETON wrote:
>>
>>> I have noticed that the ICV in my Prius runs way more often than I
>>> expected, and for more than just recharging the batteries. The cute
>>> animation in the LCD display clearly shows that most of the time the
>>> ICV is powering the wheels, i.e., providing more power than the
>>> electric motor
>>> by itself can provide. I am suspicious that this is done so as to
>>> improve the Prius's "drivability" in the US; i.e., greater
>>> acceleration. Us Americans are accustomed to "tearing" away from the
>>> traffic light.

>>
>>
>> This is exactly it. They use the Gas engine more in the US to provide
>> the performance Americans expect.
>>
>> The funny thing is, the average American Prius driver drives the damn
>> car like a silver-haired Granny in the 1964 F-85 she bought brand new 43
>> years ago. So adding the EV mode would be a good idea on Toyota's part.
>> In the week I drove one, I spent some time crawling from a start, and
>> found it did NOTHING! I was getting better mileage with an AT Tercel.
>> When I started driving it 'normal', the numbers didn't budge.
>>
>>

> If the traction battery has the charged potential to move the car 1000 ft
> it doesn't matter if it's at acceleration from a dead stop or dispersed
> for the next couple of miles.
> So, I agree with your experience 100%. I disagree with your one week
> assessment of mpg though, unless you filled the tank several times during
> that week.



I was reading it off the computer...

Hachiroku $B%O%A%m%/(B 02-18-2007 08:09 PM

Re: Re:What about the mileage!?!?!?!?!
 
On Sun, 18 Feb 2007 07:59:03 -0500, mark_digital© wrote:

> BTW, I'll be at Thorn's market today sometime around 1 pm. I'm easy to
> spot. I won't be wearing a winter coat ;)



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




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