Re: Hybrids, not as great as we thought


"Andrew Stephenson" <ames@xxxxxxxxxxxxxxxxxxx> wrote in message
news:1144458995snz@xxxxxxxxxxxxxxxxxxxxxx
In article <DzDZf.4117$pZ3.556077@xxxxxxxxxxxxxxxxxxxxx>
nospam@xxxxxxxxxxxxxxxxxx "M.R.S." writes:

"Andrew Stephenson" <ames@xxxxxxxxxxxxxxxxxxx> wrote in message
news:1144372373snz@xxxxxxxxxxxxxxxxxxxxxx

[a discussion on what "regenerative braking" means, in the
context of the current Prius]

In a Prius, "regenerative braking" means exploiting the electric
generator's tendency to output electricity when its shaft turns
due to the vehicle moving. Power is drawn from it and this, by
basic principles of electromagnetic induction, causes a reactive
torque to be fed back to the shaft, which provides braking that
gets transmitted back to the wheels. (The power is taken away
and stored within the limits of efficiency in the main battery.)

Ummm... Isn't that what I just wrote??

In your mind alone, possibly. In words the rest of us saw, no.

"tendency to output electricity when its shaft turns due to the vehicle
moving" <- this means you've let off the accelerator... the vehicle is
coasting, GENERATING ELECTRICITY... (that is what regenerative braking
is...)

I was trying to phrase it in everyday terms, as you seem to have
a feeble grasp on the basics of electrical engineering. There's
no need to invoke accelerators and such system-specific features,
because r/b is a generic phenomenon. Try turning the shaft of a
small motor (preferably having a permanent magnet for excitation,
not one of those relying on residual fields and local rectifiers
to bootstrap things), with and without a short circuit across the
terminals. You should find that it turns more freely when open-
circuited than when s-c'd. That's the essence of r/b.

Forgive me, but your version of what r/b in the Prius is about is
so confused and nonsensical (as worded) as to suggest you really
should go and study a few textbooks. Why should the rest of us
have to know what we're talking about, while you babble freely?

There is no need to talk of taking feet off accelerators. That
merely signals to the control system to do whatever seems right
under the circumstances. Depending on how _much_ you've lifted
your foot, instead of applying r/b the car can be persuaded to
coast (freewheel), with no power sent to the motor or drawn from
the generator. (That, however, becomes more difficult when the
car needs to recharge the main battery; it's a practice thing.)

The Prius will also employ r/b when the "B" mode is selected (see
past discussions) though there the primary purpose is to recharge
the battery quickly. Braking is a side product of taking kinetic
energy out of the car and turning it into chemical energy in the
battery.

That statement you cut/pasted is from a Toyota press release...

Actually, no. It was my summation and my wording. If you think
otherwise, feel free to cite checkable sources. (OTOH, thank you
for your implied admiration of the quality of my writing.)

My information comes from my career as an electronics engineer.

A short career, I take it?
--
Andrew Stephenson




You know Andrew,

In the future, you should respond to posts with more maturity (please read
your first response to my post).

There is no sense in arguing with you since you aren't an authority on
automotive systems, unless you can qualify otherwise.

I'm sure your people skills are less refined than your obvious lack of
understanding of automotive hybrid vehicle systems, and probably other
vehicle systems.

People like yourselves make the usenet a source of misinformation. The
quote I took was cited from a SAE text on DC motor systems and hybrid
vehicle integration.

Sorry, and where/how did you form your opinion? If you can't qualify it,
don't respond.


.

Relevant Pages

  • Re: Hybrids, not as great as we thought
    ... In a Prius, "regenerative braking" means exploiting the electric ... coasting, GENERATING ELECTRICITY... ... That's the essence of r/b. ...
    (alt.autos.toyota)
  • Re: Who Killed the Electric Car? (PBS)
    ... The electric car was a worthless Idea. ... We don't produce enough electricity and have an underdeveloped system ... love it -- and I love my Prius. ... new thing called hybrid rage. ...
    (soc.retirement)
  • Re: Burlington gets regions first hydrogen station
    ... what kinda vehicle was that they used in the demo? ... Hydrogen as a replacement to fossil fuel is such a farce. ... tank with hydrogen. ... The hydrogen production plant uses electricity from the Burlington ...
    (misc.invest.stocks)
  • Re: Burlington gets regions first hydrogen station
    ... what kinda vehicle was that they used in the demo? ... Hydrogen as a replacement to fossil fuel is such a farce. ... Hydrogen is used to produce ELECTRICITY. ... The advantage of hydrogen is that it is clean energy as it is ...
    (misc.invest.stocks)
  • Re: Age of the automobile is kaput!
    ... Experts say e-bikes can run 30 miles on 5 cents' worth of electricity, a rate of energy consumption that makes them even more efficient than fully occupied buses." ... internal combustion driven vehicle manufacture, ... benefit of their domestic market but to use their domestic market to ... industry for exporting to the economies that can currently afford cars. ...
    (rec.bicycles.tech)