Toyota stalling may be linked to on-board computers, electroniccontrol module
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From: sctvguy1 on 7 Dec 2009 17:34 On Mon, 07 Dec 2009 22:15:12 +0000, Tegger wrote: > "hls" <hls(a)nospam.nix> wrote in > news:DMGdnUC4lMmn6IDWnZ2dnUVZ_jidnZ2d(a)giganews.com: > > >> "m6onz5a" <corvair(a)comcast.net> wrote in message >> news:abb95d2a-529e-4ee4-9eac-90fed63d1117(a)z35g2000prh.googlegroups.com. >> .. On Dec 7, 11:46 am, "Jeff Strickland" <crwlrj...(a)yahoo.com> wrote: >>> The problem is that Toyota (and others) are using what is termed, fly >>> by wire. >>> >>> In fly by wire, the gas pedal is not mechanically connected to the >>> throttle >>> body. The gas pedal has a servo that tells the computer what the angle >>> is, and the computer then sets the throttle body with a stepper motor >>> to match the angle of the gas pedal. >> >> The throttle position sensor has been used for years in different >> embodiments, >> some essentially drive by wire. I know there are differences, but the >> technology >> is not totally new nor very experimental. >> >> I remember when total drive by wire came up in rec.autos.tech, a lot of >> us really didnt like where that was leading. I still dont. >> >> >> > > > You can thank emissions and CAFE regulations for throttle-by-wire. > > With all the easy gains long accomplished, it takes some serious > trickery to get the last little bit of blood out of that particular > stone. > > And, I learned today, it appears there is a liability-regulation issue > behind the "start button". > > My understanding is that the "start button" originally had a half-second > delay before it would shut off the engine. The problem was that people > were hitting it accidentally and causing unexpected shutdowns in > traffic, leading to a potential liability situation. Therefore, the > button was given a THREE SECOND delay. Apparently the drivers of at > least some of these "runaways" HAD pushed the "start button", but > panicked when the button did not shut the engine down immediately (three > seconds must seem like an eternity in such a situation). > > Source for above: Letter to the Editor in the Wall Street Journal, > Sat/Sun Dec5/6, page A20. Title of the letter: "Lawyers Shouldn't Be > Designing Cars". > The letter also mentions a previous article in the WSJ of Dec2 ("Bring > Back the 'Off' Switch"), which I missed reading. I like my 1941 Chrysler "starter button", it does exactly what is says it is supposed to do, start the damn engine. The key turns it off.
From: dr_jeff on 7 Dec 2009 18:32
Don Stauffer wrote: > dr_jeff wrote: >> john wrote: >> >> Really. The ECUs definitely have problems, but please show us a better >> way that doesn't involve electronics. Carbs worked well, but wasted >> fuel. Without electronics, are air would be dirtier, we would use more >> fuel. >> > > Why did carbs "waste" fuel? They used enrichment at high manifold > pressure, but so do FI systems. The last generation of carburetors were > quite good. What really is the difference between a carb and a throttle > body electronic injection system? One is controlled by a pneumatic > computer, the other by an electronic one. Admittedly electronic > computers can be miniaturized, and add more computation. > > Essentially the carbs of the seventies and eighties DID have computers. > The amount of measurement of their environment and the amount of > control was remarkable. There were even the deceleration controls that > got rid of richness during trailing throttle. They were marvels of > fluidic computing. They used more fuel than was needed. |