Toyota stalling may be linked to on-board computers, electronic control module
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From: Vic Smith on 7 Dec 2009 18:10 On Mon, 07 Dec 2009 22:34:11 GMT, sctvguy1 <sctvguy1(a)NOSPAM.invalid> wrote: >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. My uncle had an early '50's Buicks. First time I was in it with him he turned the key, looked at me, and started talking to me about how good the fishing was going to be where we were going. While he was talking the engine started. Surprised me, just like he intended. Floor starter. --Vic
From: dr_jeff on 7 Dec 2009 18:29 m6onz5a wrote: > 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. >> >> > > This is where I feel the problems started.. A cable has worked great > for 100 years and now they change it.. I feel they've gone too far > with the "drive by wire" systems. What's next? Driving by brain waves?? Yet, while the pedal traditionally operates the throttle, for many years, the engines have still be controlled by a computer. So, controlling one other thing is not such a big deal.
From: hls on 7 Dec 2009 20:23
"dr_jeff" <utz(a)msu.edu> wrote in message news:EPKdnV- > They used more fuel than was needed. > The question was "why". And the answer is complicated. You can do a lot with carburetors, but you cant get the instantaneous corrections on many levels that you can get with computerized fuel injection. In addition, the engine, transmission, etc all have to be working together to get the best mileage, a feat that was not normally common to simple carbureted systems. |