Recent Engineering Debacles 7

[hidalgoe]

HellO:

What have been the results of recent engineering debacles, like Boston's Big Dig concrete section that fell and killed some folks in a car or Katrina meant for PE's as far as liability and ethics are concerned?

 

[unclesyd]

Today will be interesting as it has been reported that Toyota has replicated the acceleration excursions caused by a "short circuit" in the electronic control system first reported by ABC.
The irony of this scenario was the diagnostic system gave no error codes even after several excursions.

http://www.cbsnews.com/stories/2010/02/22/cbsnews_investigates/main6232884.shtml

 

[MacGyverS2000]

syd,

That link mentions documents talking about surging. Nothing to do with short circuits.

The documents are a red herring. People are going to exclaim "See? I told you so!", but it looks like nothing more than a transmission that can't find the proper gear for a specific small range of speeds, like it keeps changing between 3rd and 4th gear, leading to surging as it downshifts. Not dangerous, just annoying as hell. You can reproduce it easily by going up a mountain at a high altitude with a lower-horsepower car... few ECUs are programmed to properly handle that, so it hunts between the top couple of gears.

I'm curious to know more about the supposed short circuit, though...

Dan - Owner

http://www.Hi-TecDesigns.com

 

[MacGyverS2000]

Got it... David W. Gilbert, PhD., Professor of Automotive Technology, Southern Illinois University Carbondale. Here's his testimony:

http://energycommerce.house.gov/Press_111/20100223/Gilbert.Testimony.pdf

Very enlightening.

Quoting from various parts of the document:

The Accelerator Pedal Position (APP) sensor was identified in the review of manufacturers’ service literature as a significantly important ETC input for all vehicles used in the study.

With the two APP sensor signals shorted together through a varying range of resistances, all four Toyota vehicles tested thus far reacted similarly and were unable to detect the purposely induced abnormality. The types of signal faults introduced into the APP circuit should have triggered the vehicles’ ECM to illuminate a warning lamp within seconds. The ECM should have then set a Diagnostic Trouble Code (DTC), entered the vehicle fail?safe mode, and reduced engine speed and/or power. When the two APP signal
circuits are shorted together, the redundancy of the APP circuit design is effectively nullified and lost.

In addition, the shorted APP signal circuits were connected momentarily to the sensor’s five?volt supply circuit with the vehicle in drive. In all test vehicles, the ECM did not set a DTC and the engine speed increased rapidly to full throttle.

Dan - Owner

http://www.Hi-TecDesigns.com

 

[IRstuff]

Aha, so Toyota can now blame the car owners for failing to adequately maintain their cars, resulting in these shorts that caused the sudden accelerations! Whew, got out of that one! And, look Ma, we saved hundreds of millions of dollars by not having to recode the safety routines!

TTFN

FAQ731-376

 

[unclesyd]

The link posted was just another report on the same subject and it was from CBS. My reference to ABC was from their news broadcast heard several times and it was they that reported that Toyota has also replicated the test first reported on the day before. The professor who devised and performed the test with an ABC reporter, Brian Wilson, on board has or will testify before Congress.
Toyota has backed off, weaseling, the statement that the problem was absolutely not electrical/electronic, this is from testimony before Congress.

It was Brian Wilson who first broke the story of the sudden acceleration excursions.

Could it be that the Toyota people were so cock sure that anything that malfunctioned in their control system would generate an error code. No codes, no problem.

 

[JLSeagull]

If multiple accelleration sensors exist, then one could suggest that additional diagnostics to detect the short described to be "design development" as opposed to a design flaw. However additional diagnostics to detect shorted Accelerator Pedal Position sensors sounds like an improvement that should be made immediately.

 

[IRstuff]

Japan has had, for so long, a solid reputative in reliability and process improvement that they've developed superiority complex about this, not that they didn't have one to start with.

I recall that Sony, back in the 80's, was doing silicon foundry work, and a customer had a yield crash that went unsolved for months, until Sony's engineers from Japan came to the US and verified that the crash was real.

Hitachi was similarly cocky about their processing. While US manufacturers routinely had 4 or 5 test chips per wafer, Hitachi felt that it was a waste of perfectly good silicon, and had no test patterns whatsoever on their older products. At that time, such confidence was indeed justified, as their parts yielded better than any of our own parts, even though we had no idea what the ideal process parameters were supposed to be for those parts. We had has Hitachi what to set the process to, and they replied, "Don't worry, just run the wafers."

That was the heyday and legacy of Deming's work in Japan. It's likely that they've lapsed on their laurels a bit too much.

TTFN

FAQ731-376

 

[JLSeagull]

An engineer with NASA tells me that the space station software applications from Japan are flawless in stark contrast to the western software.