electronic throttle
in [Technical]
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From: jim beam on 11 Mar 2010 22:20 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. this is an example of an appropriate integrator: http://www.analog.com/static/imported-files/data_sheets/AD5220.pdf -- nomina rutrum rutrum
From: clare on 11 Mar 2010 22:22 On Thu, 11 Mar 2010 19:07:19 -0600, dizzy <dizzy(a)nospam.invalid> wrote: >clare(a)snyder.on.ca wrote: > >>Oh, it detects the lockup all right - and RELEASES all 4 wheels to get >>them turning again. Result? No brakes. They come back on again as soon >>as the wheels start turning - locking all 4 again > >You guys need better tires, and stop blaming ABS if you can't stop on >glare ice - you wouldn't be able to, anyway. Not talking glare ice. Talking thick soupy slush. I personally don't have too much trouble that way because I put narrow agressive open-tread snow tires on all the family vehicles. The tires they put on most cars today are bordering on criminal. And with the Graspics I can actually stop on black ice. Not quickly - but even on the cruiser with no ABS I can stop straight.
From: clare on 11 Mar 2010 22:22 On Thu, 11 Mar 2010 19:07:57 -0600, dizzy <dizzy(a)nospam.invalid> wrote: >clare(a)snyder.on.ca wrote: > >> In wet sloppy snow with wide tires, ABS is TERRIBLE. > >Nonsense. You drive in sloppy wet snow conditions much??
From: jim beam on 11 Mar 2010 22:32 On 03/11/2010 01:15 PM, clare(a)snyder.on.ca wrote: > On Thu, 11 Mar 2010 13:22:06 -0600, Bob Cooper<bc(a)nowhere.com> wrote: > >> In article<rsmgp5t82blf3lo6kpgno8o267227cdhtg(a)4ax.com>, >> clare(a)snyder.on.ca says... >>> >>>> >>> EVERYONE is using drive by wire, or has plans to. It has MANY >>> advantages - and is no more prone, by design, to failure than a cable. >> >> Sure. That's why all those cables in past cars went haywire and opened >> up throttles. Preaching to the choir, you are. >> You recall all the incidents of million-car recalls because of that, >> right? >> >>> A very simple electrical fault can totally screw up a mechanical cable >>> connection too. A bad ground can allow fault current to flow through >>> the throttle cable, melting the plastic sheath, causing a sticking >>> throttle. It has happened. I've seen it. >>> >> Sure. Thousands of time, probably. Millions of cars were recalled for >> that, weren't they? Throttles going wide open all over the place. >> Those were terrible times. >> >>> Mechanical devices are MORE subject to failure than electronics >>> >> Right. That's why multiple transitors, resistors, lines of code, servo >> motors, and yards and yards of wiring are so much more dependable than a >> cable and a return spring attached to the driver's foot via a pedal. >> Just makes sense. > > > You can believe what you like. 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. yes indeed. some perspective for those that don't understand - a lot of good quality electronic components are often rated for 50,000 hours use. higher spec is available rated for 100,000 hours or more. a typical car driving 300,000 miles will on average only be operational for 10,000 hours. -- nomina rutrum rutrum
From: jim beam on 11 Mar 2010 22:32
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. > > >> 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. > > 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. -- nomina rutrum rutrum |