[urq] Toyota UA debacle

Sat Feb 27 06:39:06 PST 2010

 Gents, seems a lot of debate over the 'driver' in these scenarios, when it's just not a driver issue at stake.  As I understand the issue, this is a computer programming issue, regardless of any hardware fix.  To wit:  The accelerator can be active with an active brake application.  And I agree with Ti, this doesn't bode well for those of us that left-foot-brake.  One more advance driver technique dashed in favor of safety.

BMW and Audi have built in the safe-guard to drive by wire throttle since 1999.  If there are two 'conflicting' inputs, accelerator and brake, the ecu ignores the accelerator input, regardless of the accelerator position, electronically or mechanically.  Toyota chose not to put in this safe-guard, which means, the ecu considers both the accelerator and brake positions to be two mutually exclusive inputs.  Yes, you can put your foot to the floor on the gas, and put your foot to the floor on the brake.  I suspect as of this debacle, similar to the shift-interlock via the 5000 hubbub, left foot braking, like dropping the gearshift into drive without the brake, is now not going to be possible anymore.

I don't believe for a second that braking can 'overcome' an engine at WOT, and certainly that would require a 'speed' parameter (including the fade variable spoken to here).  And, having experienced a WOT stick in a 4.2 v8 (stuck cruise control rod) 2 years ago, blaming a driver for not being able to react is premature.  In my case, the almost WOT to 60, lifting to find none...  The next few seconds to 'react' took me to 90+ before I was able to shift to neutral and cut the power.  Processing all that, and taking the risk that the ignition cut too far might lock up the wheel, was quite high stress for me.  And one of the scariest 20 total seconds of my life.  Doing that in traffic?  I back up from the driver....

The philosophy that two conflicting inputs can be valid doesn't bother me as much as the lack of *any* redundant safeguard.  It shouldn't take a catastrophic event to shut down a runaway WOT event, whether it ends up being floor mats, accelerator pedals, TPS sensors or code farts.  And, in my mind, if I have to give up my well trained quattro left foot brake benefits, to make those not so well trained 'other' drivers safer, such is the progress of electronic safeguards.

I like the idea of the concept that brake forces should be able to overcome WOT, that philosophy towards the issue will bring us some really good brake hardware.  The reality is, that isn't going to happen, more likely it's going to be more strict programming (no fooling that LFB programming in the S4 I read about 10 years ago) to those inputs, so that if you brush the brake pedal, the ecu is going to put that engine in decel mode with extreme prejudice to task.

All that said, I don't believe any of this is driver error.  Sitting in the cockpit of a WOT rocket, trying to save the lives of your passengers as you navigate obstacles, even finding the controls to over-ride a shutdown procedure, can be catastrophic in it's own right.  And I thank my lucky stars in my v8 incident, that it was me, not my wife or daughter at the wheel when I experienced the WOT stick.  I suspect a very different outcome would have faced me and my family, all over a 2 dollar piece of plastic bushing that failed.  To read here, folks speaking to the driver error is pre-emptive and prejudicial.  Having BTDT on the circumstances, I knew it was a lot of training AND a lot of luck, that got me through that 20 seconds of hell.

I fully and completely put this back on Toyota consciously making the choice to not intersect the two input parameters as a safeguard.  The 'safeguard' and integration of these inputs, makes foor mats, TPS sensors, pedal assembly, and driver error: Irrelevant.  Plain and simple, that's one expensive way to learn that the germans basic mistrust of electronics, should be the standard.

My .02

Scott J
WOT btdt

-----Original Message-----
From: Ben Swann <benswann at verizon.net>
To: 'Quattro List' <quattro at audifans.com>; urq at audifans.com
Cc: rmwoodbury at roadrunner.com
Sent: Fri, Feb 26, 2010 5:02 pm
Subject: [urq] Toyota UA debacle

More grist for the mill on the Toyota Unintended Acceleration  debacle - the 
view
expressed here are not necessarily shared by me.

What Went Wrong at Toyota?
http://www.designnews.com/blog/Made_by_Monkeys/31184-What_Went_Wrong_at_Toyota_.php?nid=
4871&rid=2152461

Toyota's Problem Was Unforeseeable
http://www.designnews.com/article/446480-Toyota_s_Problem_Was_Unforeseeable.php?nid=2321
&rid=2152461

Is EMI a Credible Theory in the Toyota Case?
http://www.designnews.com/blog/Made_by_Monkeys/31158-Is_EMI_a_Credible_Theory_in_the_Toy
ota_Case_.php?nid=4871&rid=2152461

Poor Plastic Selection Caused Gas Pedal Failures
http://www.designnews.com/article/448825-Poor_Plastic_Selection_Caused_Gas_Pedal_Failure
s.php?nid=2328&rid=2152461
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