Re: Prius seldom runs on batteries alone?

In alt.autos.toyota Chuck Olson <chuckolson01@removethiscomcast.net> wrote:[color=blue]
>
> 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.[/color]

Interesting advice -- I'll have to try this.
[color=blue]
> 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.[/color]

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" <ccreekin@yahoo.com> wrote in message
news:45d8eaaa@news.meer.net...[color=blue]
> In alt.autos.toyota Chuck Olson <chuckolson01@removethiscomcast.net>
> wrote:[color=green]
>>
>> 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.[/color]
>
> Interesting advice -- I'll have to try this.
>[color=green]
>> 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.[/color]
>
> 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.
>[/color]

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

"Ray O" wrote ...[color=blue]
> "Tomes" wrote ...
> <snipped>>[color=green][color=darkred]
>>> "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.
>>>[/color]
>>
>> 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[/color]
>
> According to the faq section at [url]www.toyota.com:[/url]
> "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.
>[/color]
OK, that's what I thought. It uses the electric motor in reverse to
generate electricity stored in the batteries. The IC engine remains out
of the picture. Now my next question is does it generate more or less
than in normal mode?
Tomes

"Tomes" <askme@here.net> wrote in message
news:QmnCh.3424$x74.109@newsread4.news.pas.earthlink.net...[color=blue]
> "Ray O" wrote ...[color=green]
>> "Tomes" wrote ...
>>
>> According to the faq section at [url]www.toyota.com:[/url]
>> "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.
>>[/color]
> OK, that's what I thought. It uses the electric motor in reverse to
> generate electricity stored in the batteries. The IC engine remains out
> of the picture. Now my next question is does it generate more or less
> than in normal mode?
> Tomes
>[/color]

I think that's backward - it dumps energy into turning the engine rather
than into the battery. Maybe MRV can explain it more clearly. She does that
sort of thing so well :-) People who have monitored the battery current with
the Ecrostech Miniscanner ([url]http://tinyurl.com/2yvbrx[/url]) report less
regeneration in "B." I've never actually checked myself, but if you want
numbers I can do that.

Mike

In alt.autos.toyota Michael Pardee <michaeltnull@cybertrails.com> wrote:[color=blue][color=green][color=darkred]
>>>
>>> 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.[/color][/color][/color]

Are you sure about this 12 mph or so? It sounds like I'm hearing
pad friction at higher speeds.
[color=blue][color=green][color=darkred]
>>> "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.[/color][/color][/color]

How do you know it reduces regeneration using B instead of braking?
Do you mean braking is more radical (more force) yielding more regenerated
power? Guess I'm used to manual transmission and want something to do.
But I see the battery charging quickly when the Prius is in B.
[color=blue]
> Possibly. The brakes are not especially big, and here in the States
> the rear brakes are drum type. I understand in Europe they are
> 4-wheel disks. Anyway, use "B" for long descents.[/color]

I wonder if the US Touring model also has 4-wheel disk brakes?

"Michael Pardee" <michaeltnull@cybertrails.com> wrote in message
news:_L6dnUQ8KennuUfYnZ2dnUVZ_qyjnZ2d@sedona.net...[color=blue]
> "Tomes" <askme@here.net> wrote in message
> news:QmnCh.3424$x74.109@newsread4.news.pas.earthlink.net...[color=green]
>> "Ray O" wrote ...[color=darkred]
>>> "Tomes" wrote ...
>>>
>>> According to the faq section at [url]www.toyota.com:[/url]
>>> "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.
>>>[/color]
>> OK, that's what I thought. It uses the electric motor in reverse to
>> generate electricity stored in the batteries. The IC engine remains
>> out of the picture. Now my next question is does it generate more or
>> less than in normal mode?
>> Tomes
>>[/color]
>
> I think that's backward - it dumps energy into turning the engine rather
> than into the battery. Maybe MRV can explain it more clearly. She does
> that sort of thing so well :-) People who have monitored the battery
> current with the Ecrostech Miniscanner ([url]http://tinyurl.com/2yvbrx[/url])
> report less regeneration in "B." I've never actually checked myself, but
> if you want numbers I can do that.
>
> Mike
>[/color]
Thanks, interesting reading there. So now I am re-understanding this as
follows: In B mode it spins the IC engine without starting the engine,
wasting off excess energy in that spinning. What is not explained to me
yet (his section of How B Mode Works was truncated off) is does it
generate electricity in this engine spinning (the reverse of how it starts
the engine up all the time)?

I think that I gleaned from this stuff that it makes less electricity in B
mode due to the spinning waste.
Tomes

"Tomes" <askme@here.net> wrote in message
news:yntCh.4267$tD2.2584@newsread1.news.pas.earthlink.net...[color=blue]
> "Michael Pardee" <michaeltnull@cybertrails.com> wrote in message
> news:_L6dnUQ8KennuUfYnZ2dnUVZ_qyjnZ2d@sedona.net...[color=green]
>> "Tomes" <askme@here.net> wrote in message
>> news:QmnCh.3424$x74.109@newsread4.news.pas.earthlink.net...[color=darkred]
>>> "Ray O" wrote ...
>>>> "Tomes" wrote ...
>>>>
>>>> According to the faq section at [url]www.toyota.com:[/url]
>>>> "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.
>>>>
>>> OK, that's what I thought. It uses the electric motor in reverse to
>>> generate electricity stored in the batteries. The IC engine remains
>>> out of the picture. Now my next question is does it generate more or
>>> less than in normal mode?
>>> Tomes[/color]
>>
>> I think that's backward - it dumps energy into turning the engine
>> rather than into the battery. Maybe MRV can explain it more clearly.
>> She does that sort of thing so well :-) People who have monitored the
>> battery current with the Ecrostech Miniscanner
>> ([url]http://tinyurl.com/2yvbrx[/url]) report less regeneration in "B." I've never
>> actually checked myself, but if you want numbers I can do that.
>>[/color]
> Thanks, interesting reading there. So now I am re-understanding this as
> follows: In B mode it spins the IC engine without starting the engine,
> wasting off excess energy in that spinning. What is not explained to me
> yet (his section of How B Mode Works was truncated off) is does it
> generate electricity in this engine spinning (the reverse of how it
> starts the engine up all the time)?
>
> I think that I gleaned from this stuff that it makes less electricity in
> B mode due to the spinning waste.[/color]

OK I found this other link that actually explains it pretty well, if
anyone cares :-).
[url]http://www.techno-fandom.org/~hobbit/cars/b-mode.html[/url]
Here is a bit copied out of that:
......Enter "B" mode. As in, "trucks use lower gear". By forcing the
wheels
to spin the engine and pump air, a good deal of that energy can be turned
to heating the air going through the engine instead of heating the brake
parts. Since fresh air is always coming into the engine, having it leave
as much warmer air provides a convenient place to dump excess energy.
In a conventional car the wheels push the engine around through the
transmission, but the Prius needs to help that process out a little bit
by actually having its combination of electric motors spin the engine.
In this case, the valve-timing in the Prius engine is advanced to increase
the amount of air taken in and the suction against the throttle flap --
which
uses much more energy than the coasting-in-"D" scenario above......

There is a lot more there that I have not copied here, but in addition to
capturing some of the energy, it is spinning it off in B mode.

Bottom line is to not use it in the hopes of saving more energy.
Tomes

In alt.autos.toyota Tomes <askme@here.net> wrote:[color=blue]
> Bill - read this link regarding what it does in B Mode:
> [url]http://www.techno-fandom.org/~hobbit/cars/b-mode.html[/url]
> It answered a bunch of questions for me about 5 minutes ago. Basically, B
> mode wastes off excess energy by spinning the IC engine. Read on....[/color]

Thanks Tomes! That was illuminating and contained many surprises,
e.g. "When accelerating... D and B produce the same behavior."

Do you know about "the Great Database Fire" that took out Priuschat?
A similar thing happened to one of the chat sites I visit, BoaterTalk.
That's one big downside of chat websites versus group (Usenet) news.
OTOH I suppose Google could discontinue groups so we wouldn't be able
to search back posts any longer.

On Feb 20, 5:59 pm, Bill Tuthill <ccree...@yahoo.com> wrote:[color=blue]
> I find Yahoo groups to be a giant PITA, so I completely abandoned them,
> but Yahoo has about a dozen Prius or hybrid "news" groups.[/color]

If I may ask, what did you find to be the problem? Other than the
adverstisements (which also plague most other Prius sites), what was
the issue(s)? The Yahoo!Groups are mainly email discussion lists, but
you do not have to read/receive/post messages via email but can be a
web-only subscriber. Yahoo has changed the email formatting and web
message archives lately, so if you're a fan of threaded responses
(among other things) you might be happy...

-Michelle, moderator or owner of quite a few Yahoo!Groups...

In general, I recommend (though I'm a moderator on only 2 of those
listed):
[url]http://autos.groups.yahoo.com/group/toyota-prius/[/url]
[url]http://autos.groups.yahoo.com/group/Prius-2G/[/url]
[url]http://autos.groups.yahoo.com/group/2007_Prius/[/url]
[url]http://www.priusonline.com/[/url]
[url]http://www.priuschat.com/[/url]
[url]http://www.greenhybrid.com/discuss/[/url]
[url]http://www.cleanmpg.com/forums/[/url]

or the more appropriate usenet newsgroup: alt.autos.toyota.prius