Fly By Wire
in [ATVs]
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From: XR650L_Dave on 4 Feb 2010 19:39 On Feb 4, 3:41 pm, JayC <j...(a)sysmatrix.net> wrote: > > It's clear to me that abs has > > the potential to cause several wrecks every time it snows. It takes > > much longer to stop... if it stops at all in some really slick low/ > > medium speed situations (especially downhill). > > Yup - been there, done that - ABS makes stopping all but impossible on > ice. I hit my brakes in an icy parking lot at a ski area two years > ago. Fully locked up would've stopped the truck in 100 feet. > Instead, my Tundra ABSed itself 1000 feet across the parking lot, > through a stop sign, across a street, down an embankment, across a > stream, and into a group of trees. I might've slowed down 5MPH the > entire time. The kids thought it was hilarious. Took a backhoe to > get me out, and I still have the crunched front end. > > JayC If you had turned the key off you'd have stopped in that 100ft. Dave
From: The Real Bev on 4 Feb 2010 22:46 On 02/04/2010 12:50 PM, dsc-ky wrote: >> Simple fix. Remove the ABS fuse and wire in a switch. > > Replace it with a blown fuse... might limit your liability if you have > an accident with the ABS disabled. :) Excellent! -- Cheers, Bev Far away in a strange land
From: N4HHE on 7 Feb 2010 12:48 On 2/3/10 1:03 PM, PlowBoy wrote: > If the dumbasses are using potentiometers, like we used to use for joysticks > on computers, there is little doubt that cheaper POTS as they are called, > soon send signal spikes not long after the first use. 1st generation Prius sent to the USA used a pair of pots in tandem. Don't have the specifics handy at the moment but was powered with something like 5V but wired such that only 1V to 3V was expected output from the wipers. Anything outside that range generated a fault. Safe from shorts and opens which eventually occurred due to wear. Current units use Hall-effect sensors which do not wear. > off throttle is probably 0 on throttle Full is probably anywhere from 25 to > 1028 (or more I'm sure) steppings, the higher the more precise the pedal > movement to throttle movement reaction would be. Don't know the resolution of the A/D converter which was used but if it was 0 - 1023 (10 bits) then Toyota only allowed inputs from 100 - 700 and anything outside that generated a fault. Don't know exactly how it handled the fault condition. Believe the engine shut down during the fault condition but would run if the input returned to legal range making the car difficult to drive. Plus a big obnoxious flashing idiot light that required a scan tool to turn off.
From: N4HHE on 7 Feb 2010 12:55 On 2/3/10 1:13 PM, IdaSpode wrote: > On Wed, 3 Feb 2010 09:16:48 -0800 (PST), JayC<jwc(a)sysmatrix.net> > wrote: > >>>> Did you hear the recently released 911 call from the father of a family >>> of 4 as their car hit the end of the freeway at 120 mph? It was chilling >>> hearing the pleas' for help and the final screams of his family as they >>> hit the barrier and went over the cliff. I heard it the other day and >>> still shake when I think of it.. >> >> The real shame is that the guy, a police officer, was too unfamiliar >> with operating a vehicle to put it into neutral when the throttle >> stuck. That technique is taught in driver's ed in high school. >> Instead, they made a cell phone call. > > Then there is that little known accessory called the ignition switch, > how hard can it be to turn the key to OFF position? Modern Toyota and Lexus don't have one of those. The key stays in your pocket. The car starts with a bit pushbutton on the dash.
From: Rowdy on 2 Mar 2010 20:49
Dean H schrieb: > I'm afraid I may be having too much fun watching this Toyota debacle > unfold. I have always thought that fly by wire systems were a sketchy > proposition. Did they sub it out to Lucas? Well, over here in Diesel country most if not all vehicles are fly by wire for years now. The '05 LandRover Discovery of my Mother has no throttle cable anymore. The arbitrarily wandering idle speed was a miracle for an electronically controlled engine, until a white haired chief mechanic smiled, whipped out some WD40 and "greased" the accelerator paddle. Problem gone. Even my 10 years old VW Bus has drive by wire. (hence one can enable the optional cruise control functionality via the OBD plug :) This among other things is rumored to be the reason why all brake light switches are twins, with both cable pairs routed independently. They not only operate the brake lights but are used as panic input to kill the engine, should the accelerator get stuck. An easy test: right foot on the accelerator, left one very gently onto the brake, as soon as the brake switch comes on the engine is instantly killed (until right above idle). The Toyota issue is similar to Mom's LandRover a mechanical one though. But the wipers of my VW Bus from time to time switch from interval mode to literally permanently on. They then ignore the wiper lever's position, happily wiping on when the lever is at "off". Cycling the ignition helps mostly, last resort: fuse out and back in. Rowdy |