My two bit’s worth on Toyota’s problems. “And forty-two”

flamin lib

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Thu Mar-04-10 03:50 PM
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My two bit’s worth on Toyota’s problems. “And forty-two”

It’s a software problem. If not that it’s EMI (ElectroMechanical Interference) or RFI (Radio Frequency Interference). Nothing mechanical that I know of can cause the symptoms of either brake or accelerator issues they are experiencing.

That said, I’m not a Software engineer, EE or ME. I made a living working closely with all three on systems very much like what we’re talking about.

First, how Drive by Wire works:

In the old days you stepped on the gas and a lever moved the throttle on the engine. Now you step on the gas and an electron position sensor tells the computer where your foot is and sends a signal to a motor that moves the throttle. There are lots of very good reasons to do things this way; it’s cheaper, it lets you isolate the passenger compartment and one system can be used on lots of vehicles. We’ve been doing this on aircraft for decades without a problem.

With cars the computer will make adjustments to the input signal (where your foot is) and the output signal to compensate for external conditions. Cold? Add a little extra throttle. Turn on the AC? Boost the idle speed a bit. In its most basic form this is an IF/THEN command and there may be dozens of them imbedded in the operating system or every function. Under very specific but unpredictable conditions the operating system may instruct the system to do something bad. Remember the HAL 1000 in 2001, A Space Odessy? Well, sorta like that. This sort of thing is usually de-bugged in the beta phase of testing and if not can be duplicated and repaired once found. If identified it can be fixed with a software update (GM could do it by On-Star and you’d never know it) or by a simple chip replacement.

Then there’s EMI/RFI. We live in a soup of magnetic waves and always have, from solar flares to cell phone signals. All this energy generates tiny electrical impulses in everything including the wiring system of Toyotas (and everything else). That’s why you can’t use a cell phone on airplanes or in ICU rooms. Sometimes the impulses mimic signals the operating system is expecting, like maybe where your foot is on the throttle. This is a harder fix because it’s a shielding issue. In aircraft everything is either enclosed in conductive material or has devices to absorb extraneous energy inputs (filters). In aircraft money is no object. In cars every last $.0001 matters. The last year Ford made the full sized Thunderbird it came in $800 over budget (on a $25000 car) and they fired the whole engineering team. In aircraft the Government says, “You WILL make it safe,” and in consumer goods we say, “You WILL make it cheap.”

So the problem isn’t with Toyota, it’s with people. We want everything for nothing. No new taxes, maintain the pricing on cars even though they’re 100x better than they were, supersize that meal even if I’m not hungry and lets all go to Walmart.