Exponent: Gilbert's work not realistic - would make any car accelerate

True, but try crawling under the hood, closing it, and making a cell call. It doesn't work as well once you get rid of the windows.

Tom

 

There are still plenty of large gaps, and wires ('antennas') protruding outside the engine compartment, to allow plenty of outside EMI into the engine compartment. Add in some high power sources inside, and EMC is still an important issue.

 

I wonder what the probability was of a incidence unintended acceleration coming out on the same day as the Toyota's presentation. It was actually quite high IMHO.

 

..and multiply the probability of a CHP cruiser showing up and able to ride along side a "runaway" Prius and giving instructions to the driver.

Fantastic.

 

Agreed. I was only making the point that the engine compartment is much better shielded than the passenger area.

Feed through from wires and leads can bugger up even the best enclosure.

Tom

 

Correct, but try getting AM reception inside a tunnel. (There are great openings on the sides of a tunnel.) The reception will be terrible or non-existant. Good point, it depends on the wavelength of the signal, and likely the position in relation to the openings. I still think the car shell largely shields external influence.

 

Except those supplied by the driver.

Tom

 

I've now looked at the Exponent Report as well as Gilbert's Report.
As I recall from the news stories, the Exponent Report was vetted by Toyota's lawyers, as well it should have been. I know what I might advise Toyota, and I have ideas about advice that other lawyers might give Toyota. Therefore, I would suggest that we have not yet reached the point of full disclosure of what Exponent might have to say. (Which in my view is OK, unlike the views of some others.)

As a non-engineer, I am left with two big unanswered questions, before I am willing to put Gilbert to bed:

1. Exponent says there is no evidence of the wear, exposed wires, etc. that you would expect to see if there had been a short of the type that Gilbert induced. But I don't remember Exponent saying that it had access to the cars (or even to pictures taken by Toyota at the time) which experienced unintended accelleration. Am I missing something? Or is this really missing from the Exponent report? Surely this is a very important question.

2. In the other thread on the Gilbert Report, kbeck says:
"They didn't report anything about the ECU, beyond saying "nice doggie" when they talked about it.

"That's odd. Very extremely odd, since the ECU is the most likely place for something to go wrong with the reception of signals from the pedal assembly. I would have expected some analysis and/or statement saying that there was redundant silicon in there, or that no single-point fault in the ECU could cause unwanted acceleration without a DTC. Those statements, or something like them, are notable by their absence." [end kbeck quote]
Can we therefore rule out a "silicon manufacturing/degrading" fault in these accellerations?

 

lol.

I wasn't really going for that. I meant that people underestimate probabilities of certain things, and overestimate other probabilities. From this thread here are the order of probabilities as I estimate

toyota throttle and brakes operating properely > toyota pr presentation on unintended acceleration and incident of unintended acceleration happening > false report of unintended acceleration in prius > gilber scenario > death from lack of oxygen at normal temperatures and pressures of someone without related medical problems.

 

If I'm remembering my amateur radio stuff correctly, the 800 Mhz cell phone band might have a wavelength of around a foot (13 inches, give or take), but the 1900 Mhz band will be less than half of that (6.2 inches, more or less). WiFi (2400 Mhz) is 4.7 inches. You'll need some pretty damn tiny windows at that point...

 

AM radio wavelengths are about 600 to 1800 feet. Most tunnel openings are tiny compared to that, so the rebar in the structure provides significant attenuation.

FM radio wavelengths are typically about 10 feet. The original cell bands are closer to a foot, PCS bands shorter, and WiFi just a few inches. That shield impenetrable to AM becomes increasingly transparent at higher frequencies. That car shell, with its big windows, long slot antenna around the hood, open bottom engine compartment, and wire penetrations all of over place, is not a good shield to those frequencies.