Toyota Throttle Electronics Easily Confused
in [Technical]
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From: jim beam on 27 Feb 2010 10:20 On 02/27/2010 06:23 AM, MLD wrote: > > "jim beam" <me(a)privacy.net> wrote in message > news:DM2dnWaVF4D_CBXWnZ2dnUVZ_tWdnZ2d(a)speakeasy.net... >> On 02/25/2010 08:41 AM, MLD wrote: >>> >>>> <SNIP> >>> <SNIP> >>> >>> My take on the sudden, uncontrolled acceleration is that it's root cause >>> is tucked away somewhere in the electronics. Has anyone ever got >>> involved in dealing with RFI (Radio Frequency Interference)? I've dealt >>> with two interesting cases where RFI caused a significant problem in >>> aircraft. One, complete loss of engine power. Cause was a radar signal >>> that triggered the closing of a fuel Shut-Off Valve. Happened every time >>> an aircraft (helicopter) flew past a particular radar station. >> >> this is a great post. the most important point is exactly this - "it >> happens every time [state condition and result]". >> >> this is /not/ what is observed to be happening with toyota, otherwise >> the results would be repeatable and investigatable. and occurring in >> significantly greater numbers. >> >> >> > The >>> second, also a helicopter, two engines: Every time the pilot pushed the >>> transmit button on his high frequency radio one engine rolled all the >>> way back to its Idle setting--it recovered as soon as he released the >>> button. The cause of both incidents was improper shielding of the >>> aircraft wiring harnesses. The aircraft manufacturer was sloppy in his >>> design--improved shielding fixed both problems. Cars now are more and >>> more dependent on electronics and somehow can't shake the feeling that >>> spurious signals are causing some of these unexplained incidents. >> >> good point, but if so, why are they not repeatable? people use cell >> phones, cb radio, drive under power lines with gnarly harmonics all >> the time - nothing. why would it suddenly happen to toyota just >> because they stole gm's thunder in the cash-for-clunkers fiasco? >> >> >>> As a >>> side note; military electronics are subjected to rigid testing; >>> bombarded with all kinds of RFI signals to determine if there is any >>> undesirable behavior. I doubt if the automotive industry comes anywhere >>> close to that kind of testing or evaluation. >> >> car electronics get all kinds of bombardment testing too - the "under >> hood" environment is hugely hostile because of spark ignition >> interference - the electronics have to not only survive, but survive >> well.. >> >> >>> MLD >> >> > Your comments are valid. Having said that--the problem of being > susceptible to any kind of electrical interference may not be a > fundamental design issue but rather inadequate, sloppy, careless work > procedures (you pick the word) during assembly/manufacture. That might > account for why the total fleet has not affected and why only random > individual cars end up with the problem. Purely speculation on my part. i'd buy that, but the probability fades to practically zero when you factor in driver error as a cause. > One thing that is required in Military/Commercial aircraft engine > Control System design is a fault analysis that looks at each potential > failure, which is then classified with respect to its severity and > potential impact on the behavior of the engine/aircraft. Any failure > that is classified as Class 1--severe loss of engine power, overspeed > etc must be eliminated. Redesign is required to remove the Class 1 label. > I would imagine that something along a similar vein is conducted in any > system where safety and life is an issue--how rigorous and how much does > cost play into the equation is open to question. > MLD agreed. however, as a hardware example that tegger will confirm, the number of verified honda engine computers failures is single digits. no amount of talking can get around that hard evidence that honda are taking reliability very seriously. i see no evidence that toyota are any different. -- nomina rutrum rutrum
From: MLD on 27 Feb 2010 11:02 "jim beam" <me(a)privacy.net> wrote in message news:QKydnV3cOePUpRTWnZ2dnUVZ_t-dnZ2d(a)speakeasy.net... > On 02/27/2010 06:23 AM, MLD wrote: >> >> "jim beam" <me(a)privacy.net> wrote in message >> news:DM2dnWaVF4D_CBXWnZ2dnUVZ_tWdnZ2d(a)speakeasy.net... >>> On 02/25/2010 08:41 AM, MLD wrote: >>>> >>>>> <SNIP> >>>> <SNIP> >>>> >>>> My take on the sudden, uncontrolled acceleration is that it's root >>>> cause >>>> is tucked away somewhere in the electronics. Has anyone ever got >>>> involved in dealing with RFI (Radio Frequency Interference)? I've dealt >>>> with two interesting cases where RFI caused a significant problem in >>>> aircraft. One, complete loss of engine power. Cause was a radar signal >>>> that triggered the closing of a fuel Shut-Off Valve. Happened every >>>> time >>>> an aircraft (helicopter) flew past a particular radar station. >>> >>> this is a great post. the most important point is exactly this - "it >>> happens every time [state condition and result]". >>> >>> this is /not/ what is observed to be happening with toyota, otherwise >>> the results would be repeatable and investigatable. and occurring in >>> significantly greater numbers. >>> >>> >>> > The >>>> second, also a helicopter, two engines: Every time the pilot pushed the >>>> transmit button on his high frequency radio one engine rolled all the >>>> way back to its Idle setting--it recovered as soon as he released the >>>> button. The cause of both incidents was improper shielding of the >>>> aircraft wiring harnesses. The aircraft manufacturer was sloppy in his >>>> design--improved shielding fixed both problems. Cars now are more and >>>> more dependent on electronics and somehow can't shake the feeling that >>>> spurious signals are causing some of these unexplained incidents. >>> >>> good point, but if so, why are they not repeatable? people use cell >>> phones, cb radio, drive under power lines with gnarly harmonics all >>> the time - nothing. why would it suddenly happen to toyota just >>> because they stole gm's thunder in the cash-for-clunkers fiasco? >>> >>> >>>> As a >>>> side note; military electronics are subjected to rigid testing; >>>> bombarded with all kinds of RFI signals to determine if there is any >>>> undesirable behavior. I doubt if the automotive industry comes anywhere >>>> close to that kind of testing or evaluation. >>> >>> car electronics get all kinds of bombardment testing too - the "under >>> hood" environment is hugely hostile because of spark ignition >>> interference - the electronics have to not only survive, but survive >>> well.. >>> >>> >>>> MLD >>> >>> >> Your comments are valid. Having said that--the problem of being >> susceptible to any kind of electrical interference may not be a >> fundamental design issue but rather inadequate, sloppy, careless work >> procedures (you pick the word) during assembly/manufacture. That might >> account for why the total fleet has not affected and why only random >> individual cars end up with the problem. Purely speculation on my part. > > i'd buy that, but the probability fades to practically zero when you > factor in driver error as a cause. > > >> One thing that is required in Military/Commercial aircraft engine >> Control System design is a fault analysis that looks at each potential >> failure, which is then classified with respect to its severity and >> potential impact on the behavior of the engine/aircraft. Any failure >> that is classified as Class 1--severe loss of engine power, overspeed >> etc must be eliminated. Redesign is required to remove the Class 1 label. >> I would imagine that something along a similar vein is conducted in any >> system where safety and life is an issue--how rigorous and how much does >> cost play into the equation is open to question. >> MLD > > agreed. > > however, as a hardware example that tegger will confirm, the number of > verified honda engine computers failures is single digits. no amount of > talking can get around that hard evidence that honda are taking > reliability very seriously. i see no evidence that toyota are any > different. > > > -- > nomina rutrum rutrum Again no issue with your comments--but strange things happen and if you've been around long enough sooner or later you get to see some weird ones that come out of the blue completely unpredictable. Case-in-point---Two ECUs interconnected sending signals back and forth to each other. During operation they happened to be in different temperature environments. The flux residue on some solder joints actually created a millivolt signal as a result of the difference in their ambient temperatures. The mv signal was treated as a error signal that effected the behavior of the system. I think that we both agree that something is going on that can't be explained away by pointing to a stuck accelerator pedal and I don't think that it is a mechanical issue. MLD
From: jim beam on 27 Feb 2010 11:19 On 02/27/2010 08:02 AM, MLD wrote: > > "jim beam" <me(a)privacy.net> wrote in message > news:QKydnV3cOePUpRTWnZ2dnUVZ_t-dnZ2d(a)speakeasy.net... >> On 02/27/2010 06:23 AM, MLD wrote: >>> >>> "jim beam" <me(a)privacy.net> wrote in message >>> news:DM2dnWaVF4D_CBXWnZ2dnUVZ_tWdnZ2d(a)speakeasy.net... >>>> On 02/25/2010 08:41 AM, MLD wrote: >>>>> >>>>>> <SNIP> >>>>> <SNIP> >>>>> >>>>> My take on the sudden, uncontrolled acceleration is that it's root >>>>> cause >>>>> is tucked away somewhere in the electronics. Has anyone ever got >>>>> involved in dealing with RFI (Radio Frequency Interference)? I've >>>>> dealt >>>>> with two interesting cases where RFI caused a significant problem in >>>>> aircraft. One, complete loss of engine power. Cause was a radar signal >>>>> that triggered the closing of a fuel Shut-Off Valve. Happened every >>>>> time >>>>> an aircraft (helicopter) flew past a particular radar station. >>>> >>>> this is a great post. the most important point is exactly this - "it >>>> happens every time [state condition and result]". >>>> >>>> this is /not/ what is observed to be happening with toyota, otherwise >>>> the results would be repeatable and investigatable. and occurring in >>>> significantly greater numbers. >>>> >>>> >>>> > The >>>>> second, also a helicopter, two engines: Every time the pilot pushed >>>>> the >>>>> transmit button on his high frequency radio one engine rolled all the >>>>> way back to its Idle setting--it recovered as soon as he released the >>>>> button. The cause of both incidents was improper shielding of the >>>>> aircraft wiring harnesses. The aircraft manufacturer was sloppy in his >>>>> design--improved shielding fixed both problems. Cars now are more and >>>>> more dependent on electronics and somehow can't shake the feeling that >>>>> spurious signals are causing some of these unexplained incidents. >>>> >>>> good point, but if so, why are they not repeatable? people use cell >>>> phones, cb radio, drive under power lines with gnarly harmonics all >>>> the time - nothing. why would it suddenly happen to toyota just >>>> because they stole gm's thunder in the cash-for-clunkers fiasco? >>>> >>>> >>>>> As a >>>>> side note; military electronics are subjected to rigid testing; >>>>> bombarded with all kinds of RFI signals to determine if there is any >>>>> undesirable behavior. I doubt if the automotive industry comes >>>>> anywhere >>>>> close to that kind of testing or evaluation. >>>> >>>> car electronics get all kinds of bombardment testing too - the "under >>>> hood" environment is hugely hostile because of spark ignition >>>> interference - the electronics have to not only survive, but survive >>>> well.. >>>> >>>> >>>>> MLD >>>> >>>> >>> Your comments are valid. Having said that--the problem of being >>> susceptible to any kind of electrical interference may not be a >>> fundamental design issue but rather inadequate, sloppy, careless work >>> procedures (you pick the word) during assembly/manufacture. That might >>> account for why the total fleet has not affected and why only random >>> individual cars end up with the problem. Purely speculation on my part. >> >> i'd buy that, but the probability fades to practically zero when you >> factor in driver error as a cause. >> >> >>> One thing that is required in Military/Commercial aircraft engine >>> Control System design is a fault analysis that looks at each potential >>> failure, which is then classified with respect to its severity and >>> potential impact on the behavior of the engine/aircraft. Any failure >>> that is classified as Class 1--severe loss of engine power, overspeed >>> etc must be eliminated. Redesign is required to remove the Class 1 >>> label. >>> I would imagine that something along a similar vein is conducted in any >>> system where safety and life is an issue--how rigorous and how much does >>> cost play into the equation is open to question. >>> MLD >> >> agreed. >> >> however, as a hardware example that tegger will confirm, the number of >> verified honda engine computers failures is single digits. no amount >> of talking can get around that hard evidence that honda are taking >> reliability very seriously. i see no evidence that toyota are any >> different. >> >> >> -- >> nomina rutrum rutrum > > Again no issue with your comments--but strange things happen and if > you've been around long enough sooner or later you get to see some weird > ones that come out of the blue completely unpredictable. > Case-in-point---Two ECUs interconnected sending signals back and forth > to each other. During operation they happened to be in different > temperature environments. The flux residue on some solder joints > actually created a millivolt signal as a result of the difference in > their ambient temperatures. The mv signal was treated as a error signal > that effected the behavior of the system. then they should have been signaling digitally, not using analog. millivolt differences are not digital signal thresholds. > I think that we both agree that something is going on that can't be > explained away by pointing to a stuck accelerator pedal and I don't > think that it is a mechanical issue. > MLD no, we don't agree on that because i don't accept the presumption that "something is going on". the facts we have are very clear, despite all the hyteria, bullshit and astroturf: 1. there have been only two cars involved in fatalities. and in both cases, there is nothing to suggest there was a simultaneous failure of the vehicle's brakes, ignition switch or transmission selector that would have allowed the drivers to safely bring these vehicles to a halt. 2. we have a whitehouse getting directly involved in what should be an agency's job after the debacle called "cash for clunkers" backfired. this is a political systems failure dude, not electronics systems. -- nomina rutrum rutrum
From: Bob Cooper on 27 Feb 2010 13:33 In article <dbadnQQMhN-Y2xTWnZ2dnUVZ_i2dnZ2d(a)speakeasy.net>, me(a)privacy.net says... > > On 02/27/2010 08:02 AM, MLD wrote: > > > > Case-in-point---Two ECUs interconnected sending signals back and >>> forth > > to each other. During operation they happened to be in different > > temperature environments. The flux residue on some solder joints > > actually created a millivolt signal as a result of the difference in > > their ambient temperatures. The mv signal was treated as a error signal > > that effected the behavior of the system. > > then they should have been signaling digitally, not using analog. > millivolt differences are not digital signal thresholds. > Total nonsense, said merely to say something. > > > I think that we both agree that something is going on that can't be > > explained away by pointing to a stuck accelerator pedal and I don't > > think that it is a mechanical issue. > > MLD > MLD, though you have made some valid technical points, your judgement is lacking in evaluating personalities. You're are talking to a madman, and he won't agree with you. > no, we don't agree on that because i don't accept the presumption that > "something is going on". the facts we have are very clear, despite all > the hyteria, bullshit and astroturf: > > 1. there have been only two cars involved in fatalities. and in both > cases, there is nothing to suggest there was a simultaneous failure of > the vehicle's brakes, ignition switch or transmission selector that > would have allowed the drivers to safely bring these vehicles to a halt. > There are many more than 2 Toyotas reported to have "unintentionally accelerated." > 2. we have a whitehouse getting directly involved in what should be an > agency's job after the debacle called "cash for clunkers" backfired. > This might help. Maintenance advice. http://www.ehow.com/how_2352403_clean-tin.html "Clean your tin hat with plain dish washing soap and a soft cloth. If your tin gets dirty you can clean it with a little dish soap and a soft cloth. Be sure to remove all of the soap and water with a dry cloth so your tin will not rust." > this is a political systems failure dude, not electronics systems. Dittohead.
From: Clive on 27 Feb 2010 13:50
In message <dbadnQQMhN-Y2xTWnZ2dnUVZ_i2dnZ2d(a)speakeasy.net>, jim beam <me(a)privacy.net> writes >2. we have a whitehouse getting directly involved in what should be an >agency's job after the debacle called "cash for clunkers" backfired. Why did it backfire? Our news was that things (Auto wise) were on the up in your country because of Cash for Clunkers. -- Clive |