Edmunds and the Crowd-Sourcing Competition

Edmunds is planning to announce a competition with a prize of $1 million to detect and propose a solution to the sudden and sustained unintended acceleration of Toyota cars.   Crowd-sourcing has worked in many other contexts, so why not here?   (Those of us who posted possible theories about the cause of the acceleration problem may feel like chumps right about now 😉

It is important to keep in mind some aspects we know of the situation :

  1. The acceleration problem does not seem to happen in every car and even in cars where it does happen, it does not seem to happen always.  These facts imply that the problem is not fully deterministic.   Look for intermittent failures.   (There may be permanent failures which manifest themselves as a component/subsystem that needs replacement).
  2. If Edmunds  is looking for a solution to the sudden unintended acceleration problem  “once and for all”, it needs to be pointed out that such a silver bullet is highly unlikely to exist.   If there are a thousand models with unique electronic throttle control system designs out there, there can be (many) more than thousand unique ways for these systems to fail.
  • Engine control modules are, simply put, complex.  They take care of engine control including fuel injection, sparking, cruise control, throttle control, ignition control, traction control, etc. etc. with an array of fail-safe mechanisms.   The design (and implementation) space is correspondingly complex and very large.  These are multi-dimensional systems:- cost, reliability, functionality, maintainability, safety and initial cost of investment are but a few of the dimensions that are traded against each other.   There can be core technological limitations in the electronics but how one integrates a fail-safe design around such limitations can be as varied as the human imagination.  Things could go wrong on the mechanical, electrical, electronics, software and human interaction fronts and/or interactions among these.   So, there is no silver bullet.  These are systems designed by a multi-disciplinary cadre of engineers with different experiences and foundations.   Yes, they can also make mistakes and/or incorrect assumptions once in a while.
  • Blaming SUA on a driver “always” would be meaningless when any system has a non-zero rate of failure and must be based on assumptions about the environment in which it is working.
  • Blaming the SUA problem on the electronics “always” would be equally meaningless since humans, ahem, will always be humans and occasionally err.
  • All entrants into this competition should be aware that these are safety-critical (i.e. life-critical) systems.  Don’t tinker with the system while it is running unless you really know what you are doing.  At the end of the day, trust me, your life is worth more than a million dollars.  So, please do exercise caution.

All that having been said, it is within the realm of possibility that some out-of-the-box idea can reproduce the problem repeatably.    Finding it could be very easy (sometimes the right imagination and creativity goes a long way), or could be very complex (just watch Toyota asserting in many different ways through many different people including the CEO and grandson of the founder of Toyota that nobody has been able to show that there is a problem in the electronics).

May the best idea win.   Just be safe.


2 Responses to “Edmunds and the Crowd-Sourcing Competition”

  1. throbbo Says:

    I read with interest your paper on the lack of reverse-voltage suppressors on Toyota relays. It’s unconsionable that Toyota chooses to omit a 5 cent diode on each relay to prevent reverse EMF when the field in the relay collapses. As you know voltage across a coil = L di/dt; ie if the inductance L is substantial and dt (the time it takes for the voltage across the coil to collapse), the voltage will be very high indeed.

    Let’s not neglect the throttle motor. It, too, is inductive, and is most likely driven by a transistor in the ECU. See http://www.drmarksays.com/wp-content/uploads/2010/01/taskthrottlebody32.pdf for a description.

    If the transistor driving the motor shorts, it would very probably drive the throttle motor to full open. No “fail-safe” short of cutting power to the motor could correct this situation.

    Toyota presumably has engineers on its staff a lot smarter than me, and hopefully they have considered this situation. However, if they are willing to save 50 cents per car by not using back EMF diodes in their relays, what other electronic shortcuts have they taken?

    Anyway, thanks much for the great blog and the interesting paper!

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s

%d bloggers like this: