OT: Thoughts on Toyota Recall, Safety Circuits Design

[harryting]

ABC News just reported that the problem now looks related to electronics/software.

All I can find on ABC news is "Akio Toyoda Apologizes for Safety Problems, Then Drives Away in a Black Audi."...

Kinda funny, since Audi 5000 was the last victim of gas pedal issue.

 

[rootboy]

Not to belabor a point, but on NPR today:

"Now the committee said this in a statement, Im kind of quoting here, our government figures show nearly twice as many people died in Toyotas from sudden acceleration problems in the last decade than in cars from all other automakers combined."

http://www.npr.org/templates/story/story.php?storyId=123098947

 

[bikerdude]

So..
Anyone know how these pedals work?
Maybe a lever on a pivot that turns a pot?
0 to 10volt signal, 4 to 20mA maybe? Surely not an expensive encoder device. I could see where condensation could foul up the voltage signal from the wiper on a pot. Kind of hard to determine what it is if you can't reproduce the situation. I doubt any software problems but it shouldn't be ruled out without proof of hardware problems. Last time I worked on a throttle body the mechanical pedal linkage connected to a cable, cable then connected to lever on throttle body thereby rotating the butterfly in the throttle body. I believe there must have been a sensor in the throttle body that determined the position somehow.

BD

 

[leitmotif]

My thoughts:

Drive by wire is always a bad idea.

I worked in a plant that put drive by wire steering on some tow vehicles to make them easier to turn, thereby reducing sprains and strains. Sure they were easier to turn, and made for less work on the drivers, but more work for facilities maintenance fixing holes in block walls, and repairing the trucks...One broken coupler or wire and the truck steering would go in a random direction.

What do they gain by drive by wire throttle? Simplified cruise controls? Fewer (cheaper) parts in the throttle linkage? I bet they wish they stuck with the good old fashioned cable and spring returns on the both pedals and throttle plates now.

I dont know if drive by wire is so bad - we have had cruise control for how many decades and few problems (I think ??).
However either touching the throttle or brake turned it off. In the case of my Ford pickup turning a turn signal also turns it off - not sure what to make of that.

Properly set up AND the ONLY involvement with brake is to set engine to idle I think it would be OK. As I said in previous email maybe an E stop on fuel supply or something of that nature = I know manual shutoffs were common on older stationary diesels and were court of last resort.

Dan Bentler

 

[seaston_65]

I can't help but think of all the times I've been called to a machine because "The program is screwing up" only to find, of course, a machanical problem.
I find that because you can't "see" or touch the "program", it gets blamed a lot. Of course this is all assuming that Toyota has properly tested their software, and I really hope they did.

Personally I think this is most likly a mechanical problem, which may be totally unrelated to the actual peddles. But who really knows? Apparently the techs looking into it sure don't.

Oh and a side note, I love standard transmissions, and it would take a hell of a salesman to get me in anything but. If my accelorator ever stuck, I simply press the clutch and pull over to the side. Gotta love old school technology.

 

[caddymac]

What do they gain by drive by wire throttle? Simplified cruise controls? Fewer (cheaper) parts in the throttle linkage? I bet they wish they stuck with the good old fashioned cable and spring returns on the both pedals and throttle plates now.

I think one of the big gains for drive by wire is a reduction in NVH (Noise, Vibration, and Harmonics). Drive by wire also allows for some nice tweaking in the fuel delivery to increase gas mileage.

I know there are a lot of advantages to no longer having a key, but the fact that you have to hold down the off button for several seconds is a big safety risk in my humble opinion. In a panic situation, there aren't enough seconds to even think about the next step.

 

[rdrast]

I don't know what to think. I've had a Toyota for years, with not a single problem. I know many others in the same situation - years of ownership, hundreds of thousands of miles, no issues at all.

It does seem like a lot of hype to me, and now with "Congressional Investigations", I almost wonder if Washington is trying to distract the US citizens with yet another tangent whilst they scheme to steal more money and get re-elected.

Cars are complicated, now more so then ever, and getting even more complicated every day. I see no way to make anything 100% safe, and 100% flawless, even the lowly paper-clip can be dangerous, and is prone to failure.

The only numbers I'd even pay serious attention to, would be the actual percentage of accidents attributable to this issue as a function of the number of 'affected' vehicles on the road.

Life is risk, daily.

Accelerator return springs, throttle plates, and mechanical accelerator cables have stuck, bound, and broken for years on every model of vehicle. Parts Break. Things wear out. Things can also be poorly designed. I don't know what this issue actually is, but I'd venture that the media is pushing it to be a bigger problem then it really is.

 

[jstolaruk]

I have to disagree Rdrast. Saying that deaths (if they are actually caused by this problem) can be acceptable if they are boiled down to percentages and are less than a "limit" is, in my book, not acceptable. Thankfully, this Congress disagrees too. An inquiry won't hurt.

 

[rdrast]

Then what about deaths caused by poor roads? Poor signage? Lack of maintenance? Poor signaling? Too little road capacity? But that isn't being taken care of in any sort of coordinated fashion.

And that is still ignoring the biggest problem, which is simply bad driving, idiotic distractions, poor vehicle maintenance, personal AND commercial.

-- Edit...
I want to clarify one thing, a CONGRESSIONAL INVESTIGATION can only serve as a grandstand for sound-bites. That's it. House and Senate members are clueless about essentially everything. An NHTSA review would be more appropriate, and more likely to lead to discovering actual truths.

Second, sort of off topic, but perhaps not, point would be that way back when, a time that I played around with motorcycles, I actually attended an eight week course on bike safety (paid for), which included training in how to lay down a bike at speed, how to deal with blowouts, bad conditions, slicks, gravel, and how to deal with surprises. That was an extremely valuable experience, and well worth the time and money. It may be that there should be similar courses for automotive safety, but it seems more important here and now to pretty much just hand out licenses to any and all comers.

 

[jstolaruk]

No argument with the other causes but this issue has a relatively easy fix - redesign & deploy the fix at the mfg's expense.

A Congressional Investigation also sheds a negative light on the manufacturer, one that I'm sure they wish they could avoid.

 

[Johnster]

I'm pretty sure that all the gas pedals in the affected models are pedals attached to a position encoder.

In my brother's 1997 VW, the throttle position sensor (TPS) has 2 potentiometers attached to it (2 wipers, 2 traces, 4 voltage points) As you open the throttle, one pot goes from a high resistance to a low resistance, the other goes from low to high. The ECU has a summing function that compares the 2 resistances and throws a code/idle's the motor if they dont track. Good controls design.

So VW had this in 1997, I must assume that Toyota had this in 2009 =) This lends credence to the 'stuck accelerator pedal' issue.

I just got my latest "Car and Driver" mag yesterday, and they did some testing on how long it takes a car to stop from 60mph with the brakes applied or not(they were thinking floormats at the time of the test). IIRC their average cars took 100-something ft to stop from 60, and 200-something ft to stop from 60 with the brakes applied. They also tested a Roush Mustang (500hp?) which took 100+ft to stop from 60 and 900+ ft to stop from 60 with the brakes applied- whoops =)
Most importantly, they tested a Lexus(!) model that has software that cuts power when the brakes are applied. Not all Toyota models have this software in place- the difference in braking distances was 10 or 20 ft for the 'safer software' model- a vast improvement over the other tested cars.

Lots of manuf's have that 'cut power when braking' software interlock, which is also good controls design, I think that any manuf. who doesnt now, should be flogging its software guys to update their product ASAP.

It sucks that Toyota's reputation will take a serious hit from this, and lots of lawmakers with nothing better to do will grandstand and posture while they could be learning about issues and improving this country... But maybe the price of Toyota Sienna's (Toyota's unrecalled Minivan) will come down into my price range because of this =) I'd love a Sienna XLE AWD with power liftgate, dual boob tubes for the kids and heated leather power massage passenger chair for the wife =)

(Nevermind, its just more stuff to break =)

-John

 

[PLCRookie]

It sucks that Toyota's reputation will take a serious hit from this,
-John

Not really.... it will just give me more leverage when I go to buy my next Toyota..... Can you say "Discount"?

 

[gas]

I have to agree with rdrast on 2 counts.
I bought a Toyota BECAUSE it was recalled and have owned them for 25 years.
I had a Mercedes that was junk and sold it. I took a used Camry to the dealer for checkout. I was told there was a long list of recalls on it and to buy it and bring it back and leave it for a week. They rebuilt the motor, brakes and did some suspension work. Cost me less than $100. We put almost 200,000 trouble free miles on that car. I have had American cars that had clearly defined problems but the manufacturers would not do anything about it. Explain to me once again why we bailed out GM?
Two:
We have the finest congress that money can buy. The grandstanding is just a diversion while they move closer to the till....

 

[Kent Hostetler]

Not sure what to make of all of this, but we cannot ignore that there is the potential that a problem exists with the design.

What I find curious at this time is that several Lexus models have the most complaints, yet there are no Lexus models in the recall.

And while I don't have the whole story, and whether or not the drivers are to blame (as I'm sure there are many of these that are driver error), some finer points really bother me:

1) There have been instances of "runaway" vehicles which had the floor mats removed. The latest was the event that occurred around Christmas when a car ended up in a pond, and the mats were in the trunk.
2) There are no federal safety requirements that braking override acceleration. Seems a basic design criteria when moving to drive-by-wire.
3) My BMW has drive-by-wire, but the pedal's hinge point is at the bottom. Makes sense to me...
4) After reading the NHTSA response to one driver's petition that they investigate the issues here http://www.safetyresearch.net/Library/DP09001_Denial.pdf , I am convinced that the NHTSA was unwilling to push the issue until more people died.

Kent

 

[PLCRookie]

Looks like they have identified a fix.......

The "fix" is in..

http://money.cnn.com/2010/02/01/autos/toyota_gas_pedal_fix/index.htm?hpt=T2

According to this article, the "floor mat" issue was not related to this one.