stuck accel peddle

classic Classic list List threaded Threaded
5 messages Options
Reply | Threaded
Open this post in threaded view
|

stuck accel peddle

Mark Hanson-2

Hi,

 

I'm curious since there are Prius owners on this list and I bought a 2010 Prius.  Are the brakes directly connected to the master cylinder after you go through the 1/2 inch of regen?  The dealer wouldn't tell me if there is a direct mechanical connection or just went through the foo-foo computer that decided if you really wanted to stop.  My Insight is direct I think.

 

Cheers,

Mark
     
_________________________________________________________________
Hotmail: Trusted email with Microsoft’s powerful SPAM protection.
http://clk.atdmt.com/GBL/go/201469226/direct/01/
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.sjsu.edu/mailman/private/ev/attachments/20100311/1176f4dc/attachment.html 
_______________________________________________
General support: http://evdl.org/help/
Unsubscribe: http://www.evdl.org/help/index.html#usub
Usage guidelines: http://evdl.org/help/index.html#conv
Archive / Forum: http://evdl.org/archive/
Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev

Reply | Threaded
Open this post in threaded view
|

Re: stuck accel [pedal]

NeilBlanchard
Hi Mark,

> I'm curious since there are Prius owners on this list and I bought a 2010 Prius.  Are the brakes directly connected to the master cylinder after you go through the 1/2 inch of regen?  The dealer wouldn't tell me if there is a direct mechanical connection or just went through the foo-foo computer that decided if you really wanted to stop.  My Insight is direct I think.


I've not heard that *any* car has "brake by wire"?  Certainly, the better ABS systems have the computer "looking" at the wheel speed and it can modulate the brake fluid pressure, but this is not quite the same as "brake by wire".

Sincerely, Neil
http://neilblanchard.vox.com/library/posts/




_______________________________________________
General support: http://evdl.org/help/
Unsubscribe: http://www.evdl.org/help/index.html#usub
Usage guidelines: http://evdl.org/help/index.html#conv
Archive / Forum: http://evdl.org/archive/
Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev

Reply | Threaded
Open this post in threaded view
|

Re: stuck accel peddle

Cor van de Water
In reply to this post by Mark Hanson-2
I used to own a Prius and never had any problem,
ABS working as it was expected (slippery manhole =
ABS instantly reducing brake power to avoid losing control
and quickly after the manhole I felt the brakes bite again)
Also acceleration was reduced when I tried to quickly take off
from a side-street with some loose gravel in the gutter, again
a good way to avoid losing control and spinning the car around
as I have done with another vehicle, but a little scary if you
see the traffic approaching quickly and you want to get out of
the way before them... Nothing wrong with that Prius though.

If I remember correctly the master cylinder connects to a set
of valves where the brake computer can modulate brake power,
like with every ABS enabled car.
I think (but I am not sure) that if you stomp hard enough on
the pedal, it will give you decent brake power even if the
ABS computer is out or decided that you are not allowed to
brake, because it can only modulate the power, not shut it
off completely. But I may be wrong, best is to ask this
question at Prius Chat. Those guys have the service manuals
(I only had one for my 2002 Classic Prius) and can give you
the accurate answer, if necessary reproduce the situation
and measure what the Prius does - I know that Bob Wilson
has fitted his 2010 Prius with acceleration sensors for the
purpose of being able to measure accurately what the Prius
is doing, instead of relying on lore or seat of the pants.

He measured the brake performance on "potholed" road before
and after the Prius brake software update. In essence,
about half a second unnecessary delay before ABS reactivated
the brakes was gone after update, exactly as I expected.

Regards,

Cor van de Water
Director HW & Systems Architecture Group
Proxim Wireless Corporation http://www.proxim.com
Email: [hidden email]    Private: http://www.cvandewater.com
Skype: cor_van_de_water     IM: [hidden email]
Tel: +1 408 383 7626        VoIP: +31 20 3987567 FWD# 25925
Tel: +91 (040)23117400 x203 XoIP: +31877841130

-----Original Message-----
From: [hidden email] [mailto:[hidden email]] On
Behalf Of Mark Hanson
Sent: Friday, March 12, 2010 1:52 AM
To: [hidden email]
Subject: [EVDL] stuck accel peddle


Hi,

 

I'm curious since there are Prius owners on this list and I bought a
2010 Prius.  Are the brakes directly connected to the master cylinder
after you go through the 1/2 inch of regen?  The dealer wouldn't tell me
if there is a direct mechanical connection or just went through the
foo-foo computer that decided if you really wanted to stop.  My Insight
is direct I think.

 

Cheers,

Mark
     
_________________________________________________________________
Hotmail: Trusted email with Microsoft's powerful SPAM protection.
http://clk.atdmt.com/GBL/go/201469226/direct/01/
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
http://lists.sjsu.edu/mailman/private/ev/attachments/20100311/1176f4dc/a
ttachment.html
_______________________________________________
General support: http://evdl.org/help/
Unsubscribe: http://www.evdl.org/help/index.html#usub
Usage guidelines: http://evdl.org/help/index.html#conv
Archive / Forum: http://evdl.org/archive/ Subscription options:
http://lists.sjsu.edu/mailman/listinfo/ev


_______________________________________________
General support: http://evdl.org/help/
Unsubscribe: http://www.evdl.org/help/index.html#usub
Usage guidelines: http://evdl.org/help/index.html#conv
Archive / Forum: http://evdl.org/archive/
Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev

Reply | Threaded
Open this post in threaded view
|

Re: stuck accel peddle

carrott
In reply to this post by Mark Hanson-2
On Fri, March 12, 2010 9:21 am, Mark Hanson wrote:

> I'm curious since there are Prius owners on this list and I bought a 2010
> Prius.  Are the brakes directly connected to the master cylinder after you
> go through the 1/2 inch of regen?  The dealer wouldn't tell me if there is
> a direct mechanical connection or just went through the foo-foo computer
> that decided if you really wanted to stop.  My Insight is direct I think.

One thing that applies to all petrol vehicles with vacuum assisted brakes
is that there is a limited supply of vacuum at full throttle. The engine
only makes vacuum with the throttle closed and the vacuum servo system has
a small storage tank.

On the vehicles I've driven, the stored vacuum is good for 3 normal gentle
stops and then the pedal goes very hard and you have no assistance. I
would expect there is enough vacuum for little more than one full throw of
the master cylinder. If your engine is dead or at full throttle and you
hit the brakes hard and then back off, you may find there isn't much
assistance left to hit them hard again.

If you do have a run-away, you should not hesitate on the brakes, as you
have one chance (or maybe two) with vacuum assistance.

Sorry for the off-topic post. I guess in an EV the brake system and the
traction system are independent, so the chances of loosing vacuum at the
same time as a run-away controller are much less than in a petrol car.
Except in my car, I have an AC system with regen and no vacuum assistance.
When the regen is working, it feels like I have vacuum assisted brakes. If
the controller runs away, I can always turn it off with the key
(hopefully).

_______________________________________________
General support: http://evdl.org/help/
Unsubscribe: http://www.evdl.org/help/index.html#usub
Usage guidelines: http://evdl.org/help/index.html#conv
Archive / Forum: http://evdl.org/archive/
Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev

Reply | Threaded
Open this post in threaded view
|

Re: stuck accel peddle

EVDL Administrator
In reply to this post by Mark Hanson-2
On 11 Mar 2010 at 15:21, Mark Hanson wrote:

> there are Prius owners on this list ...

There's lots of EV expertise on the EVDL - but the Prius isn't an EV.  ;-)

I'm sure there are many places to find experts on the Prius, but in my
experience, some of the most knowledgable hang out at the Prius Technical
Stuff Yahoo group.

http://groups.yahoo.com/group/Prius_Technical_Stuff

David Roden - Akron, Ohio, USA
EVDL Administrator

= = = = = = = = = = = = = = = = = = = = = = = = = = = = =
Note: mail sent to "evpost" or "etpost" addresses will not
reach me.  To send a private message, please obtain my
email address from the webpage http://www.evdl.org/help/ .
= = = = = = = = = = = = = = = = = = = = = = = = = = = = =


_______________________________________________
General support: http://evdl.org/help/
Unsubscribe: http://www.evdl.org/help/index.html#usub
Usage guidelines: http://evdl.org/help/index.html#conv
Archive / Forum: http://evdl.org/archive/
Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev