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).
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 ;-)
On Feb 18, 10:56 pm, "Ray O" <rokigawaATtristarassociatesDOTcom>
US 2004 Owner's Manual, section 2-6 "Operation of Instruments and
Controls, "POWER switch, transmission, and parking brake," "Cruise
Control," page 141:
"The cruise control allows you to cruise the vehicle at a desired
speed over 40
km/h (25 mph) even with your foot off the accelerator pedal."
Myself, I've been able to set the cruise control at 24mph, so I'd
guess that the kph is the more important trigger there...
"Ray O" <rokigawaATtristarassociatesDOTcom> wrote in message
Yeah, I just looked it up and it is supposed to be 24 MPH on the Prius.
That's better than I thought. But still, I would like to see a minimum of
'already engaged in forward motion' rather than any minimum.
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
"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.
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
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?
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 (http://tinyurl.com/2yvbrx ) report less
regeneration in "B." I've never actually checked myself, but if you want
numbers I can do that.
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.
OK I found this other link that actually explains it pretty well, if
anyone cares :-).
Here is a bit copied out of that:
.....Enter "B" mode. As in, "trucks use lower gear". By forcing the
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 --
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.
Are you sure about this 12 mph or so? It sounds like I'm hearing
pad friction at higher speeds.
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.
I wonder if the US Touring model also has 4-wheel disk brakes?
Bill - read this link regarding what it does in B Mode:
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....
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.
You are welcome, glad to be able to actually contribute something other
than opinion. It is a pretty good read, I just hope it is all correct
What is this Priuschat? Or is the question what _was_ Priuschat?
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