electronic throttle
in [Technical]
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From: jim beam on 11 Mar 2010 22:42 On 03/11/2010 06:04 PM, Dillon Pyron wrote: > Thus spake Bill Putney<bptn(a)kinez.net> : > >> jim beam wrote: >>> if you buy all this fear-mongering idiocy that electronic throttle is a >>> problem, and that brakes, transmissions and ignition kill switches can >>> all simultaneously fail causing a driver to lose control, it might be >>> worth auto manufacturers of all stripes to adopt a slightly different >>> implementation of electronic throttle [e.t.] - if not for mechanical >>> reasons, but to shut the idiots up... >> >> The lawyers, politicians, and news media can convince the public of the >> impossible (failure even a totally fail safe system) any time they >> decide to do it depending on political or monetary motivation. IOW - >> the people and companies who do a good job of designing are going to get >> punished anyway (unless they know how to play the game in a corrupt >> system). There are people in our society whose life goal is to make >> sure that that happens. > > The people who are pushing this issue have no idea about complex > software systems. You can not test for all of the potential > combinations of events. dude, the numbers of inputs for a car is not only finite, it's actually quite small. it's also very well mapped. the "combinations of events is" therefore very testable. > > Backing off on the throtle while getting airborn at the crest of a > hill with the brakes gently applied and the A/C on? I can come up > with hundreds and hundreds more. And everyone her can probbly match > those numbers without a repeat. > > The EE who hacked a failure is an academic, not a real world person. he shorted two wires. any car would react in some way to that. > You have to apply the 20-80 rule. 20% of the problems will generte > 80% of the failures. You are more likely to grind a brake pad to > metal than to have the concotted failure he caused. Much more. -- nomina rutrum rutrum
From: jim beam on 11 Mar 2010 22:50 On 03/11/2010 07:17 PM, clare(a)snyder.on.ca wrote: > On Thu, 11 Mar 2010 19:06:20 -0600, dizzy<dizzy(a)nospam.invalid> > wrote: > >> David Skelton wrote: >> >>>>> But, ABS does not >>>>> work so well in the very wet or icy conditions. >>>> >>>> Sure it does. It can't perform miracles, however. >>> >>> No, it doesn't work so well in slippery conditions. >> >> I'd love to see you prove that statement. It's a fact beyond dispute >> that it aids stability and control... >> >>> In slippery conditions, it is much easier to lock all four wheels at once >>> with a stomp on the brake pedal. Then the ABS controller cannot detect >>> wheels turning at different speeds which is required to activate the ABS >>> system. >> >> A) Does that really work? B) Why the HELL would you want to do that? > > > When you have really sloppy conditions the "high viscosity water" > causes the (wide) tires to "hydroplane" and braking causes the tire to > skid immediately. Without ABS the "skid" gets a chance to scrape down > through the slush and actually "find" pavement - allowing the vehicle > to stop. Since this does not always happen simultaneously on both > sides of the car, or better yet on all 4 wheels at once, a skewing > skid occurs - but the vehicle does slow down. By releasing the brakes > momentarily to regain directional control and then trying again, it is > possible to actually stop the car - and if you know how to drive, also > stop it straight on the travelled portion of the roadway. > > With ABS when this happens the ABS releases the brake before it can > scrape down to the pavement, so traction is not regained. The good > news is no skewing skid results. The bad news is the car does not slow > down, and although you can easily stay on the travelled portion of the > roadway, it may well be occupied by something else made of steel and > rolling on 4 wheels. - or a pedestrian - which you will undoubtably > hit. > Straight on. > And hard. > > IF you can fool the ABS into not releasing, under those conditions, > you have a chance of getting stopped - perhaps sideways. > In my experience I've NEVER been able to trick the ABS into allowing > all 4 wheels to skid - they always release. > exactly. abs has it's place for the freds, but for people that have learned how to control a vehicle in those conditions, it can hinder more than it helps. -- nomina rutrum rutrum
From: jim beam on 11 Mar 2010 22:53 On 03/11/2010 11:21 AM, Bob Cooper wrote: > In article<OtydnXBOAPs28AXWnZ2dnUVZ_rudnZ2d(a)speakeasy.net>, > me(a)privacy.net says... >> >>> >>> Though recollections get hazy, I recall the vacuum wipers always >>> slowing down - maybe even stopping, when the throttle was opened. >>> And I remember heater doors clunking closed too. >>> Think these were cars in the 1960's, Chevy, Olds, Pontiac is what I >>> drove then. >>> >>> --Vic >> >> since when did pieces of s from the 50's and 60's, with little if any >> gas flow dynamics engineering, represent modern vehicles??? > > Pay attention. They were talking about throttle effect on vacuum > wipers. > Did you confuse that with EPS and hydraulics? no, i'm not the slightest bit confused - you just like to keep saying i am. you don't have to like what i say or the way i say it, but don't make false allegations. -- nomina rutrum rutrum
From: clare on 11 Mar 2010 23:16 On Thu, 11 Mar 2010 19:20:26 -0800, jim beam <me(a)privacy.net> wrote: >On 03/11/2010 05:03 PM, clare(a)snyder.on.ca wrote: >> On Thu, 11 Mar 2010 16:04:31 -0500, clare(a)snyder.on.ca wrote: >> >>> On Wed, 10 Mar 2010 20:28:26 -0800, jim beam<me(a)privacy.net> wrote: >>> >>>> On 03/09/2010 10:15 PM, Rodan wrote: >>>>> clare(a)snyder.on.ca wrote: >>>>> >>>>> Toyota throttle has 2 hall effect sensors. The output of one tracks the >>>>> other but is offset. In other words, one starts at say, 0 volts, and the >>>>> other at, say 1 volt - and they increase in step with each other. >>>> >>>> how can that be true??? >>>> >>>> http://en.wikipedia.org/wiki/Hall_effect >>>> >>>> hall effect sensors are used for gross position detection, not small >>>> scale linear deflections. they can be used for "wot" detection, but >>>> their ability to work over a wide positioning range is limited. that's >>>> why they're used in timing for things like crank position [rotational] >>>> sensors where you're counting pulse rates, not graduation functions. >>>> >>> >>> You are wrong. Hall effect sensors are used instead of potentiometers >>> in all kinds of "variable output" controls including the throttles on >>> virtually all the electric scooters and e-bikes you see out there. >>> >>> They are called "Ratiometric Linear Hall Effect Sensors. >>> >> More research brings MORE interesting information. >> A "hall effect switch" is an adaptation of the basic "hall effect >> sensor", where a schmitt trigger and a comparator use the hall voltage >> to produce a "digital" signal. >> >> The basis of a hall effect sensor (the hall effect) is when current >> flows through a conductor in the presence of a magnetic field a >> voltage is produced at right angles to the current flow, and it varies >> with magnetic flux in both level and polarity. > >at very close proximity. there is not a "good relationship" between >proximity and output for distance. thus, if you read you link again, >you'll see that those devices are used basically just as a pulse >counters, or on-off switch sensors, not proximity distance gauges. hall >effect potentiometers use this principle i think you'll find - they >count the number of pulses from origin, then electronically integrate, >not measure distance. > Nope - they are used direcly as rotary controls like potentiometers, with on-chip amplifiers built in..Generally they are single ended - in other words using only N or only S magnetic polarity so the voltage is only positive or only negative - not using rail to rail dual power supplies. They are LINEAR, and actually extremely simple in concepr and application. The schmitt trigger type is as you say, strictly on and off, with designed in hysteresis. The fact that there IS hysteresis supports the fact that the output of the Hall "cell" itself IS linear, or at the very least variable. >this is an example of an appropriate integrator: > >http://www.analog.com/static/imported-files/data_sheets/AD5220.pdf
From: clare on 11 Mar 2010 23:19
On Thu, 11 Mar 2010 19:32:56 -0800, jim beam <me(a)privacy.net> wrote: >On 03/11/2010 05:10 PM, clare(a)snyder.on.ca wrote: >> On Thu, 11 Mar 2010 18:35:29 -0500, Bill Putney<bptn(a)kinez.net> >> wrote: >> >>> clare(a)snyder.on.ca wrote: >>> >>>> ...Properly designed and implemented >>>> electronic controls are more reliable than properly designed and built >>>> mechanical systems. Ther is NO WEAR, and NO MOVING PARTS. Moving parts >>>> either wear or seize or break in time. >>>> If electronic devices are operated within their design voltage and >>>> temperature parameters they can last virtually forever. 10s of >>>> thousands of operating hours at the minimum. >>> >>> You forget one thing: Modern (automotive) electronics are made using >>> surface mount components, and surface mount solder bonds (as currently >>> done in the modern automotive world) are particularly bad at >>> withstanding years of thermal cycling and other environmental exposure. >>> All these electronic module failures (hard and intermittent) are >>> probably 90+% due to the failure of surface mount component-to-board >>> bonds. A chain is only as strong as its weakest link - and that is it. >>> >> >> You forget the main culprit - LEAD FREE SOLDER. > >even lead solder fatigues under thermal cycling. the mitsuba main relay >in older honda civics is a classic example. That is true - but lead-free lets a lot MORE gremlins out of the cage!!! > > >> >> >>> You might argue "Well, then they aren't properly designed and >>> implemented, are they?". That may be true, but it is a fact that you >>> can't get away from in the present state of automotive electronic >>> manufacturing. >>> >>> I claim that the admission has to be one of two things: >>> (1) Surface mount electronics as currently utilized in the present >>> automotive industry do not fit into the category of "proper design and >>> implementation", or >>> (2) Even properly designed and implemented electronics (by modern >>> standards of the automotive industry) are prone to failure. >>> >>> Perhaps you would choose (1)? Or do you not accept that electronic >>> modules in our automobiles have real failure rates over the life of the >>> vehicle? >>> >>> You might have one valid counter to this if you were to say that a >>> proper design would be fail safe (for the uninitiated, that means that >>> things may fail, but when they do, they do so in a safe manner). But >>> then, can we anticipate all failure modes and analyze their results? (I >>> have served on FMEA teams for major manufacturers, so I know what I'm >>> talking about in this area.) It probably is a circular argument, >>> because you could always claim that "...then it is not properly designed >>> and implemented, is it?", and I couldn't disagree with you. And actually, in the vast majority of situations the fail IS "safe" - with the result of a failure being non-operation - not full. >> >> Bean counters. And greenies. Lead free solder and bean counters on the >> same project can definitely cause problems. >> >> But bean counters and engineers on the same project ALWAYS cause >> problems - whether mechanical or electronic - which IS why I qualified >> both conditions - electronic and mechanical - as properly designed and >> implemented. >> >> You caught that. >>> >>> Perhaps this relates back to some of the Toyota problems, perhaps not. >>> But electronics do fail - you have to decide if that is due to (1) or >>> (2) above. >> ANd all told, Toyota has had a lot less of those problems, up 'till >> now, over the long haul, than virtually ANY American manufacturer. >> Toyota electronics over the years have been WAY above average. >> NipponDenso components in particular. |