Toyota Throttle Electronics Easily Confused
in [Technical]
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From: Tegger on 26 Feb 2010 21:20 Conscience <nobama@g�v.com> wrote in news:hm9s04$3ao$1(a)news.albasani.net: > On 2010-02-26 16:19:14 -0800, "C. E. White" > <cewhite3remove(a)mindspring.com> said: > >> >> "Tegger" <invalid(a)invalid.inv> wrote in message >> news:Xns9D2B60597CD01tegger(a)208.90.168.18... >>> >>> It is not possible to drive a 6.5'-tall SUV like you would a >>> 4.5'-tall coupe, and expect to be able to keep the shiny side up all >>> the time. >> >> Naturally. > > One exception: Jeep Grand Cherokee SRT8. Skid pad of 0.93, if memory > serves. Not quite 6.5', but close. > > Skidpad doesn't tell all, unfortunately. Skidpad is steady-state. The real- world is anything BUT steady-state. Real-world drivers abruptly yanking the wheel around--often in conjunction with panic and sudden braking--are what overturn or ditch even the most well-behaved of motor vehicles. -- Tegger
From: jim beam on 26 Feb 2010 22:45 On 02/26/2010 03:53 PM, C. E. White wrote: > > "jim beam" <me(a)privacy.net> wrote in message > news:S6KdnQr3EeRo_BrWnZ2dnUVZ_hOdnZ2d(a)speakeasy.net... > >>> You apparently are dedicated to deflecting >>> any discussion of the Toyota problems by any and all means, including >>> lying. >> >> except that i'm not and you are. where were you on the frod rollover >> fiasco ed? did we hear you baying for blood over the hundreds of >> americans killed by frod executives anxious to avoid costly redesigns >> on vehicles /proven/ faulty. > > LIAR. > > > Ed no i'm not ed. the frod evidence was subpoenaed on their own letterhead. but this is why you're just an astroturfer, not a real lobbyist - you're not smart enough to know what you can win and what you can't. -- nomina rutrum rutrum
From: jim beam on 26 Feb 2010 22:45 On 02/25/2010 08:41 AM, MLD wrote: > > "Vic Smith" <thismailautodeleted(a)comcast.net> wrote in message > news:31uco5pm34c0aupnah8d0lsh3g3ttkq4kt(a)4ax.com... >> On Thu, 25 Feb 2010 12:22:58 +0000 (UTC), Tegger <invalid(a)invalid.inv> >> wrote: >> >>> On Feb 23, 7:47 pm, john <johngd...(a)hotmail.com> wrote: >>>> The floor mats and sticking pedal accounts for only 30% of the >>>> problems. The true cause of sudden acceleration is still not known so >>>> no real solution is possible. IMO it's the electronics. >>> >>> >> --Vic >> <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 -- nomina rutrum rutrum
From: jim beam on 26 Feb 2010 22:47 On 02/26/2010 03:34 PM, C. E. White wrote: > > "Hachiroku ハチロク" <Trueno(a)e86.GTS> wrote in message > news:hm75sm$stp$5(a)news.eternal-september.org... > >> I don't get where he said that. A lot of people are pointing to the >> electronics, but since the affliction spans a lot of models, electronics >> seems out of the picture. > > I am not an expert on software, that's not all you're not an expert on ed. > but it seems to me that the basic > programing modules would be similar across the product lines. I am sure > there are variations in response parameters, but I would guess that the > basic processing strategy would be the same across the product lines. I > am sure it probably evolves over time, but I would be suprised if all of > the vehicles with electronically controlled throttles didn't share the > same basic programming. I have a couple of Toyotas repair manuals, and > the electronic throttle control sections are virtually indentical (2.4L > I4, and 3.0L V6). that's an underwhelming argument ed. sadly underwhelming. > > Ed -- nomina rutrum rutrum
From: MLD on 27 Feb 2010 09:23
"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. 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 |