Drive by wire
02-03-2010, 04:49 AM
#1
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Drive by wire
Heard on the news this morning that the throttle issue associated with the recall at Toyota may be a result of interference anomolies with their drive by wire throttle systems. True or not this is one of the reasons I chose to buy a MY05. Maybe I'm just old school but I much prefer a mechanical throttle over a DBW set up.
02-03-2010, 05:46 PM
#6
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DBW allows a bunch of engine controls that smooth throttle response, save gas, and reduce emissions. It won't be many years before you can't buy a new car without it.
Now if you want scary, consider steer by wire, which is actually one of the car-safety holy grails. No steering column to impale yourself on (collapsing columns were an improvement, not a solution).
If it makes you feel better, conside that large aircraft uses all DBW type controls. Of course they don't necessarily buy from the lowest bidder (like cars), have redundant systems, and a higher level of preventive maintenance.
Oh, and watch for brake-by-wire which is coming even sooner -- less unsprung mass at the wheel, faster build-up of braking force, less or no fluids at end-of-life.
Now if you want scary, consider steer by wire, which is actually one of the car-safety holy grails. No steering column to impale yourself on (collapsing columns were an improvement, not a solution).
If it makes you feel better, conside that large aircraft uses all DBW type controls. Of course they don't necessarily buy from the lowest bidder (like cars), have redundant systems, and a higher level of preventive maintenance.
Oh, and watch for brake-by-wire which is coming even sooner -- less unsprung mass at the wheel, faster build-up of braking force, less or no fluids at end-of-life.
02-03-2010, 06:08 PM
#7
i don't see a problem with DBW or braking by wire for that matter with a daily driver. however DBW regardless of whatever marketing bullshit we have been fed really seems to hurt throttle response. and I would imagine brake by wire will really hurt the driving experience of a proper sports car on the track. would the brake pedal feel like butter all the way to the floor?
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02-03-2010, 06:12 PM
#8
Originally Posted by Penforhire,Feb 3 2010, 06:46 PM
less or no fluids at end-of-life.
Seriously though, I think it is silly to be worried about x-by-wire. There will be some hiccups, but I would bet it is going to have an overall positive effect on safety.
Penforhire, how exactly will there be less unsprung mass in the brake by wire system?
02-03-2010, 07:08 PM
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I work with computers as a career. Funny enough, most time/money is spent on fixing problems, not sitting around like the Maytag repairman.
Anyone who thinks "X-by-wire" is a harmless wave of the future, or thinks that people who oppose the proliferation of X-by-wire technologies in daily driver cars are Luddites is naive.
What I find apalling about the throttle-by-wire systems is the way it licenses Porsche and BMW to charge extra for the option to make the throttle "more responsive." That's akin to charging thousands for a lighter throttle return spring on a mechanical linkage, only it costs even less to actually deliver.
And what I find scary is that pretty much all racing organizations have extremely strict rules requiring throttle-return springs, usually requiring two for redundancy. This is a safety issue to them. Now if we give throttle control over to a computer rather than the human brain, there is no need for a throttle-return spring because the spring doesn't have to break for the throttle to stick wide open. A spring is perhaps present, but it serves no safety purpose as the potential issue of a stuck throttle can't be prevented by a spring. A simple short can defeat all mechanical safeties.
I realize that solid-state enbedded systems are not as error-prone as a multi-purpose OS in the hands of lusers, but as a very tech-savvy individual I see the experts' encouragement of the common layperson to simply accept that computer-controlled systems are somehow safer because they don't get tired or distracted is incredibly simplistic and ignores basic common sense. Or at least the sense that is common to people who routinely deal with the hiccups of electronic components. Failure modes are not consistent or predictable. And Murphy's law is always in full effect.
It might be worth noting that Murphy was a technician, not a social scientist or an economist.
As has been mentioned, airplanes have pioneered this technology, and it is now ubiquitous in modern planes. But what is conveniently ignored in that assertion is the FAA-mandated service intervals. I don't see the US government, much less the gov'ts of the rest of the world mandating FAA-level system service intervals.
Anyone who thinks "X-by-wire" is a harmless wave of the future, or thinks that people who oppose the proliferation of X-by-wire technologies in daily driver cars are Luddites is naive.
What I find apalling about the throttle-by-wire systems is the way it licenses Porsche and BMW to charge extra for the option to make the throttle "more responsive." That's akin to charging thousands for a lighter throttle return spring on a mechanical linkage, only it costs even less to actually deliver.
And what I find scary is that pretty much all racing organizations have extremely strict rules requiring throttle-return springs, usually requiring two for redundancy. This is a safety issue to them. Now if we give throttle control over to a computer rather than the human brain, there is no need for a throttle-return spring because the spring doesn't have to break for the throttle to stick wide open. A spring is perhaps present, but it serves no safety purpose as the potential issue of a stuck throttle can't be prevented by a spring. A simple short can defeat all mechanical safeties.
I realize that solid-state enbedded systems are not as error-prone as a multi-purpose OS in the hands of lusers, but as a very tech-savvy individual I see the experts' encouragement of the common layperson to simply accept that computer-controlled systems are somehow safer because they don't get tired or distracted is incredibly simplistic and ignores basic common sense. Or at least the sense that is common to people who routinely deal with the hiccups of electronic components. Failure modes are not consistent or predictable. And Murphy's law is always in full effect.
It might be worth noting that Murphy was a technician, not a social scientist or an economist.
As has been mentioned, airplanes have pioneered this technology, and it is now ubiquitous in modern planes. But what is conveniently ignored in that assertion is the FAA-mandated service intervals. I don't see the US government, much less the gov'ts of the rest of the world mandating FAA-level system service intervals.