So it would be an good opportunity for someone to make the point: There comes a time when technology as applied to machinery meant for general public use becomes so complicated as to be self defeating.
No sane citizen is asking for an automobile which, avocationally, advises on investments and analyzes the theology of Niebuhr.
The issue at hand will be Toyota's gas pedal, excitable as a Celtic maiden and no more predictable by any logic yet confided to humankind.
So maybe someone could just note that by 1930 automobile engineers had perfected a fully observable, serviceable, and replaceable control loop for feeding fuel to an engine. A spring, a couple-three steel rods, and a sentient operator. Sticky accelerators could be cured with a couple of squirts from an oil can, and you hardly ever had to consult with Washington about it.
7 comments:
Maybe if the Toyota people talk very slowly, the congressoids will understand what they are trying to say. Now, how they explain using a computer to perform a task performed admirably by a mechanical link-up, is another matter. Our 2001 Camry, with the old-fashioned mechanical hook-up works just fine. It's those new-fangled computer assisted rigs that run wild. BTW, has nobody heard of turning off the ignition? JAGSC
1 - it's actually a big cost-saving measure to go with electronic throttle. You aren't just replacing the throttle pedal and linkage... you're replacing the cruise control module and solenoid, and the idle speed control device (however their particular one used to work, throttle-kicking or vacuum bleed). Cruise becomes just a matter of a little extra code in the ECM, because it's already handling instrument function and is aware of road speed. Throttle tip-in mapping also becomes a matter of however they want it to feel, rather than configuring the angle of the pedal cable arm or using cammed cable spools or any of the other tricks manufacturers have used.
2 - Toyota worked themselves into this corner regarding the other controls, with just plain bad design. Push-button ignitions won't allow you to turn the motor off with the transmission in drive, but the transmission won't allow a shift out of drive when there's throttle input... such as when the feedback loop has gone screwy. The brakes may also be interlocked in some manner... in essence, with a throttle feedback loop error the ECM blindly trusts the input it gets and interprets an accelerate command, and the other lockouts leave you completely, utterly screwwwwwwed.
3 - the 'solution' of chopping throttle with brake application shows that there's a hardwired flaw... and will piss off anyone who drives in a sporty manner, as heel-toe shifting is now impossible, and using the brakes to bias thrust under low traction situations is right out too. You're going to see a lot more toyotas stuck in winter.
There's nothing wrong with using electronics for any of the above systems. There's a middling problem with tying so many critical systems together because that introduces new unexpected issues. There's HUGE problems in implementing said systems without sanity checks such as having two sensor inputs from the throttle control, or any kind of emergency override procedure. The lack of a way to kill the engine *any time you want* is particularly inexcusable. Hell, my GMC sonoma shuts the engine off all the time *by itself* on purpose when it detects the engine's doing braking work on a downhill (yes, it's supposed to, 'cheater' jake brake just by zeroing the fuel injectors).
Just what I'd expect from a man who slaps a Buck Rogers top on his 1911. :)
I instantly yield to your superior technical knowledge of the command and control systems imposed on autos and trucks over the past generation. And I suppose they do cut manufacturing costs.
But since I sold my last share of Ford and General Motors years ago, my interest is strictly that of a vehicle user, and two of my criteria are : "Is there chance that I can (a) understand and diagnose a simple problem and (b) Is it possible I might be able to fix it under a shade tree?
By the early 90s the answer to those questions was no. Expensively no. Some $300, including a short tow, to replace an ignition module after the truck simply refused to start despite a good starter spin. A decade earlier I'd have quickly isolated it to distributor parts or the coil and fixed at curbside. Maximum cost: maybe $40. It was unlikely however, that curbside repair would have been needed. Usually, primitive electrical parts warned of impending failure through hard starting, rough runnning, loss of power -- things an aware driver will quickly notice. Digitals seem to just get pissed off and commit mayhem without a seemly advance notice -- much like Prime Minister Tojo on Dec. 7, 1941. :)
The manufacturer may save money, the user doesn't.
A case in point. I recall replacing two fuel pumps in the past fifteen or so years, one on a 70s GM in-line six, the other on a 1984 Nissan. For some reaason I recall the nearly exact cost of the Chevy pump, $28. The replacement time was well under an hour. The Nissan was easier yet, even though It had an inaccessible pump. A $20 or $30, half-hour workaround consisted of cutting a hose and splicing in an aftermarket electric pump.
I thought of that recently when I was yakking with the mechanic changing my oil. On the next hoist a minivan waited for replacement of the fuel pump located, insanely in my view, inside the tank. I asked the cost of the job. About $900.
And yes, part of the problem is my own fault. I could buy the books and diagnostic gear and simply learn how outthink the evil and undisciplined little protons and electrons. Probably won't, though.
Addendum, Strange:
I meant say it's good to hear from you and that I'm not the only guy around who would like to see a little more content over on your blog.
One more comment about cost savings. A few years ago, Ford saved a few bucks by placing the gas tank on Pintos in close proximity to the differential. And, we all know how that turned out. JAGSC
The key to understanding electronics is that they do *exactly* what they're told... 99.9% of what goes wrong with modern control systems is that what it gets told is wrong. You're expecting the ECU to hear "throttle up to level 30" when you press on the gas, but a floating ground has made the supply voltage to a resistive potentiometer rise a wee bit and it hears "throttle up to 300" and off ye go like a shot... or it's a PCM system and your cellphone's interference is *just* happening to stick a couple beats in teh signal now and then, and that filters out to about 250% more input than expected....
The good part though, and what makes it relatively easy, is that there have always been sanity checks built in... and the computer tells you what's insane with computer codes. Ex: any chrysler car from ~1988 to roughly 2000 you can hop in, insert the key, and turn it on-off 3 times leaving it in on, and just calmly count the code numbers off the flashing check engine light. "12" "55" is "here comes the message:" "all done", meaning none of the sensors went out of range within memory. If it sticks a "21" in the middle you know your car's idling like a SOB because the computer saw the oxygen sensor reading hasn't been changing. Or you can make it *work* for you... most cars with solenoid idle control, setting base idle is usually as easy as yanking a vacuum hose, which forces a high idle and makes the solenoid withdraw... then unplug the solenoid, set the idle where it should be, and plug everything back up. Viola, done.
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The pinto was no different from any other small car Ford made from 1962 till then, with one exception. Ford's practice was to drop the gas tank into the trunk from the top, making the trunk floor essentially the (reinforced) top of the gas tank. The filler usually was on one side or the other.
The Pinto had some packaging issues with a side-mounted filler hose because the wheelwells were open and took quite a bit of the fender space, so ford made the filler hose rather short and angled so as not to have it sticking out into the cargo area.
Now, here's where the trouble starts. Ford had a weight target with the Pinto. They had trouble keeping it. So, what was deemed to be "expendable" weight was removed from the rear fender reinforcements and rear bumper structure. It still met 5mph standards so it was *that* much weaker than other cars. The problem began when you got enough speed in the impact to overcome the bumper mounts and start crumpling sheetmetal.
Timewise: Bumpers hit. Rear of pinto start collapsing the bumper into it's mount. They run out of travel. The rear fenders begin to bow outwards, the rear glass shatters, and the tail panel begins caving in from the top and the rear structure caving. Soon it meets a relatively strong gas tank... but the fenders are bowing, so it draws towards the front of the car, and soon can't move past the axle. Tank's now getting squished... and the fenders are moving far enoguh in relation to RIP OFF THE FILLER HOSE. That plus squeezin' equals a rush of gas out the filler hose hole... and it being a hatchback, means a healthy spray of gasoline all over the inside of the vehicle, and I hope nobody smoked that day.
There was a retrofit frame pack that could be installed but it added ~200 pounds to the car. By the end of the run the Pinto had grown from ~2300lbs to just on the edge of breaking 3 grand. All because what had worked fine in millions of vehicles before wasn't really suitable for a car that had no trunk lid or package tray to stop fuel spray before it got to the meaty bits inside the cabin.
K-cars and derivatives have always been 5-star crash rated (for the testing of those periods). I attribute this wholly to really fugly long front overhang and offset engine mounts (hit an Aries hard in the front and it'll pound the oil pan into the pavement) and putting the gas tank where it belongs, under the back seat, with the heavy unibody floor pan between you and it.
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