I don't own a hybrid, but have had a question about them on my mind:

We know that on hybrid cars like the Prius, during braking the battery is
recharged as the wheels act like generators. But I wonder about two things:

- Is there a conventional braking system pressing metal against metal as a
backup for these cars in case the generator function during braking doesn't
work properly; and
- If so, what kind of wear does this backup braking system endure, in
general (presumably far less than on conventional cars.)

Thanks in advance.

"M. Hamill" <mhamill (AT) fuse (DOT) net> wrote

There is a conventional braking system but it is brake pad material against
metal, not metal against metal (unless you don't replace the pads after they
are worn).

The service brake would have the same or less wear than on a conventional
car.
--
Ray O
correct the return address punctuation to reply

In article <4bd43$4397a00b$d8442746$32274 (AT) FUSE (DOT) NET>
mhamill (AT) fuse (DOT) net "M. Hamill" writes:

I recently enquired of Toyota UK about the details of the Prius
braking system. Some of my comments have previously been posted
but here goes again...

The Prius subsystem which handles braking is a blend of electric
regenerative and conventional hydraulic technology.

As you tread on the brake pedal the system notes how you did so:
how hard; and how suddenly. From this, it works out (very fast)
what braking force is required. As much of this as possible is
provided by regenerative braking; the rest of done by hydraulic
braking (with the usual brake pads and such).

There are several useful benefits from this.

(a) If either of the available braking methods fails, the other
continues to provide some kind of slowing force. If the electric
side fails, I infer the hydraulic provides all of what's needed.

(b) Regarding your second question, I suppose that the brake pads
experience less wear, because regenerative braking is essentially
"non-contact" and will handle most of the low-force braking (such
as gentle touches on the pedal).

You should realise that much of the Prius is conventional. What
is new is how the old is blended with the new.
--
Andrew Stephenson

As an interesting side note, the dealer I work for has ONE recorded case of
replacing brake pads on a Prius. I've seen some with well over 100k miles
and over 50% of the pad lining remaining.

"Ray O" <rokigawa (AT) tristarassociatesDOT (DOT) com> wrote

One follow up question, does it still have a conventional e-brake/ parking
brake on the Prius ?

<reportspam (AT) shaw (DOT) ca> wrote

way, passenger cars do not have an "emergency brake." They are called a
parking brake because they only apply the brakes to the rear wheels and will
not stop a vehicle as quickly as the service brake.
--
Ray O
correct the return address punctuation to reply

In article <QJ4mf.74841$Gd6.9085@pd7tw3no>
reportspam (AT) shaw (DOT) ca "<reportspam (AT) shaw (DOT) ca>" writes:

The Prius does a good job of emulating a conventional automatic
gearshift car. On the dashboard is a button which has the same
effect as shifting the lever to Park. It locks the transaxle as
usual and is strong enough for level ground. The knob to select
[R]everse/[N]eutral/[D]rive (and new [b]attery-recharge option)
is just below this button, with functions lined up in the same
sequence as on a standard gear lever: imagine the arc which your
hand moves through during operation of a standard shift; the same
arc is followed in a Prius, just higher up at dashboard level.

Above the rest for your left foot is a easy-use foot brake that
engages a very normal mechanical brake. Forget to disengage this
and it obstructs your left foot; there is also a warning light.
--
Andrew Stephenson

In article <c6d24$4398edd8$180fead6$7774 (AT) msgid (DOT) meganewsservers.com>,
"Ray O" <rokigawa (AT) tristarassociatesDOT (DOT) com> wrote:

But in case of hydraulic failure, the mechanical "parking" brake will
still function as an emergency brake, correct? I've always called it an
"emergency" brake for that reason, and I do practice stopping the car with
it (comes from my training as a naval aviator, I guess).

Merritt

"Merritt Mullen" <mmullen8014 (AT) mchsi (DOT) com> wrote

Yes, in case of total hydraulic failure, the mechanical parking brake will
still function as an "emergency" brake but stopping distances will probably
be at least triple the distance with a normally functioning brake since the
front brakes do most of the braking. Nothing like the stopping power of a
tailhook though!
--
Ray O
correct the return address punctuation to reply

Andrew Stephenson wrote:

The B position is an engine braking function. Seems to me its only
purpose is to help in long downhill runs, simulating a stick shift car
using the engine to back down a little.

Gary Eickmeier
New Owner