Toyota Recall 7

[keller36]

Hello. I am new to the forum and had a rather extensive question. I am wondering what system is causing the sudden acceleration problems in Toyota vehicles as well as the specific part in that system, if any specific part is respoinsible. I was also wondering, depending on the system involved in the problem, whether the problem is electrical, mechanical, or a problem in the vehicle's software. Thank you for any responses.

 

[GregLocock]

I agree, a poorly maintained brake system might fade before stopping even a relatively low powered car. But I'd be surprised if a newish car suffered from that - fluid changes are presumably based on some sort of performance based requirement. If you choose to drive an unmaintained vehicle, that's fine, but cars have service requirements for a reason.

C&D's test seems like a good way of pointing out that in the general case of brake vs engine, brakes win, and EVERY car I have driven in the past month (X5, Fusion Hybrid, Edge,Highlander, assorted Australian cars) always allow you to select neutral, at whatever speed, at whatever throttle opening.



Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[BrianPetersen]

dicer, substantially all of the involved cars have ABS (they are all moderate-to-high-end late model vehicles) and EVERYTHING on those cars except the power steering has at least some involvement with the computer system (in the case of the ABS system, it is the ABS module itself).

And therein lies the problem; complex software-based electronic systems are extremely hard to validate.

 

[thruthefence]

Any of the exchanges selling "law firm" futures contracts?

I'm long "Toyota Lawsuits" if there are.

 

[izzmus]

YvesLLewelyn, it can't suddenly come to life any more than the engine will start up overnight in your driveway. In many/most new cars, the ignition switch is not actually switching power on or off, it just sends a signal to a controller.

 

[YvesLLewelyn]

Well it does seem that these things may suddenly "come to life" and to have a "mind of their own" - this is, after all, what this thread is about - the Prius suddenly deciding (allegedly) to speed up etc. unasked. My thought was that the electric/battery part of the system would be more likely (and more able) to do this than the petrol bit.

 

[DanEE]

I see repeated comments in this and other threads on this site about PCs occasionally locking up, with the inference that the op systems in DBW inherently have the same problem.

PC operating systems and RTOS systems used in DBW is comparing apples and oranges.

I would think that anyone who doesn't have a clue about RTOS could understand the concept of a dead man controls used on many locomotives.. You not hit button within required timeframe, train gonna stop via fully independent control system from main op control.

I first learned of same concept used in RTOS event driven code more than 30 years ago. Even your Ethernet adapter connecting your computer to a network has embedded dead man timers to kick the adapter off the network under certain circumstances.

So far as good old reliable cable and mechanical fuel control systems that many wish for.. in my driving experience.. will I've experienced the following...


Stuck throttle run away on a tri-power 389 Pontiac
(killed it with ignition switch): check

broken cable actuated clutch pedal: check

Failed cable actuated auto transmission shifter: check

Stuck wide open carburetor secondary butterfly: check

Stuck carburetor float literally causing gasoline to pour down over hot exhaust manifold: check

Failures to date with DBW: zero.

 

[mattsooty]

DanEE

Totally agree with you; however, I tired of this debate ages ago.....

MS

 

[dicer]

DanEE, yes I think your compairing apples to oranges, I think the key word is 30 years ago. And unless you are the design engineer in charge of Toyota automotive electronic control systems, then I think you may not be totally up to par on the latest and greatest, if it was as simple as a basic RTOS system, you wouldn't see the abundance of control units placed throughout the vehicle, and complex communication protocols between them, let alone all the proprietary circuitry and software, and not to forget the closer component densitys now. And again if its not the systems failing, then it is some EM based commandeering of the system. The reasons would be obvious.

 

[DanEE]

Yep, nobody can be everywhere, but one sort of gets an idea of the complexity of the design (especially if one's life has been spent in similar systems of high complexity). This is not a new problem. To put it in perspective how does the complexity of Prius System and any other DBW design compare to the design and testability required to build an Intel Core 7 processor with high yield and reliability containing 731,000,000 transistors? or NVIDIAs GPU processor with 1.4 billion transistors? or IBM Blue Gene Supercomputer with up to 16 cabinets, with each cabinet containing holding 1,024 compute nodes.

The DA systems behind these complex products would be above all things, the most interesting to see first hand, but understandable that this has alway been the most guarded of intellectual property.

Although there are a lot of specifics marked as proprietary and not disclosed in FSM Volumes 1 through 4 approximately 5000 pages for the Prius (my 19 pound collection of volumes only for the 2006 model, sorry), does remarkably disclose a tremendous amount of information on the monitor strategy, enabling conditions, malfunction thresholds, and fail safes in the system. I find the 471 page ES (Engine Control System) section in Volume 1 a particularly interesting read and also the 569 page HV section (hybrid control) in volume 2. btw I count 5 major processors on the BEAN bus and another 5 on the CAN, but I guess that depends on the defintion of major versus minor. Anybody can buy these documents for about $610.22 including tax and shipping :<)

The Oak Ridge National Lab tear down study published about 4 years is quite revealing on the electro-mechanicals but doesn't touch upon control except in the most basic aspect.

One of Toyota's patent descriptions on the power demand/energy storage/control algorithms is 92 pages long, and a good concept description. Compare to most, 4-5 concept pages seems typical.

I agree RTOS systems aren't so simple, nor are they the only technique, many favor Finite State machines implemented in program logic arrays as a simpler more verifyable design. Interesting to read a bit on Wind River Systems development of the Common Core System for the Boeings 7E7 Dreamliner and here on some of the work going on.

http://www.cotsjournalonline.com/technologies/view/RTOS

So far as the "must be EM theory", I think the level of discussion in this engineering forum could be more fruitful if it evolved more toward specifics on the standards and test practices and whether they are adequate. Anybody close to and a bit more up to date on the list of generally used automotive EMC/EMI standards and test practices than below?

CISPR 12 IEC Global X Radiated emissions and immunity 2001
CISPR 25 IEC Global X Radiated immunity 2002
ISO 7637 ISO Global X Transient immunity 2002
ISO 10605 ISO Global X X ESD 2001
ISO 11451 ISO Global X Radiated immunity 2001
ISO 11452 ISO Global X Radiated immunity 2002
SAE J551 SAE North America X Radiated emissions and immunity 1995
SAE J1113 SAE North America X Radiated emissions and immunity 1995

How would these or current standards compare for example to the applicable sections of Mil 461-E? or the standards that were used to test the Boeing 757 FBW and documented in the NASA/LLNL FBL/PBW Program Boeing 757 HIRF Test Plan?

The latter is not so out of line as cars driven in close proximity to some of the ground facilities used in testing the 757 e.g. Greenville, NC VOA station or Wallops Island Delaware or similar facilities could receive similar exposure levels..

I guess a major point of this post is a lot of what is being put in vehicles these days and seen with controversy has a very long predecessor history in related fields. And in engineering, many times the answers can be found outside one's own sandbox.

 

[Dan320]

Buddah:
Good joke.. I don't know.. How about: My Toyota is Spastic?

 

[Ultraworld]

I watched a woman recently testifying before the house on the 6 terrifying minutes her Camry went berserk, speeding away while she was helpless to stop it. She did manage a phone call to her husband to say goodbye, but she couldn't put the car in park or just turn the car off. I really feel GM (Government Motors) is just pushing this into the forefront to improve sales of American cars. And it has helped them.

 

[mattsooty]

DanEE

Basically, when you are up against people whose only rational argument is 'well I hate DBW because I want to be in control of my vehicle' you know you might as well be conversing with somebody who is straight out of Nottingham in the 1810's and a follower of King Ludd....

MS

 

[TrackRat]

Well now we have a CHP officer claiming in his seven page report that Mr. Sikes was pressing hard on the brakes and the vehicle would only slow to 85 mph... The CHP officer knows this because he saw the brake lights on and what appeared to be Mr. Sikes pulling himself up with the steering wheel as if he was using all of his body to apply the brakes.

The CHP officer observed all this while driving at 90 mph next to the Cosmic Ray, Satan, Space Alien possesed Prius. The onboard black box data recorder and independent nhtsa engineers who inspected the Prius didn't find anything to support Mr. Sikes claims.

Wasn't their a CHP officer involved in a fatal Lexus accident a few months ago?

 

[Lou Scannon]

"Basically, when you are up against people whose only rational argument is 'well I hate DBW because I want to be in control of my vehicle' you know you might as well be conversing with somebody who is straight out of Nottingham in the 1810's and a follower of King Ludd...."
Many of us have been on both sides of the DBW equation. No doubt, when you are creating a system for use by semi- or unskilled users, DBW allows many otherwise external and unpredictable parameters to be internalised and constrained within known and reasonable boundaries. From the user's perspective, however, his freedom to control the device has been limited, and in comparison to a non-DBW system, to an unreasonable degree. Having been on both sides of this, I am very sympathetic to both points of view. For a typical user, DBW is a better solution than direct mechanical control, whether they like it or not. On the other hand, a user such as Evelrod would never be well served nor satisfied with a typical constraining DBW system aimed at typical users (jetfighter FBW systems, for one counter-example, are a different story, to be sure).

 

[DanEE]

Another view of Mr. Sikes credibility...

http://jalopnik.com/5491101/did-bankrupt-runaway-prius-driver-fake-unintended-acceleration

 

[mattsooty]

'On the other hand, a user such as Evelrod would never be well served nor satisfied with a typical constraining DBW system aimed at typical users (jetfighter FBW systems, for one counter-example, are a different story, to be sure).'

I'm not sure quite how anybody would know the optimum position for the throttle in consideration of dual independant cams, valve lifts, swirl valve, intake tuning valves etc etc.....

MS

 

[evelrod]

I have no problems with a DBW system of throttle control...I DO have a problem with ALL controls handed over to the ECM leaving me with the 'hope' that all this 'video game' stuff will work the way it is supposed to (and often does NOT).

For the very same reasons, I do not like ABS on a race car. ABS simply CANNOT out brake me on a racing circuit...Indeed, ABS that I have had on a racing circuit have "given my heart a jump" on occasion....Not good for an old man, that's for sure!

I'm not anti tech. I am anti 'stupid driver', which, in my humble opinion (yeah, right), is the biggest problem with unintended acceleration in any car. Is this a uniquely American problem?

Rod

 

[ivymike]

well sure, as noted above (I think) the forners don't have any power under the hood.

 

[mattsooty]

Rod,

I hope you didnt think I was having a dig at you personally - I most certainly was not.

Just please dont start shouting: -

"I DO have a problem with ALL controls handed over to the ECM leaving me with the 'hope' that all this 'video game' stuff will work the way it is supposed to (and often does NOT"

Some of us have more 'career' in front of us rather than behind! ;-)

I guess my point is, in this consumer driven world, people want their cake, to eat it & not get fat. Which is why all these fancy engine technologies arise in the first place.

The difficulty is that all of these technologies, when brought together, simply cannot be controlled by the main input as throttle plate position. That is why DBW is now pretty much de rigeur. And technology is not standing still to let people catch up either.

Sure as night follows day a racecar with simple control systems, when properly driven, is as pure a form of driving as one can get - however, this set up is only good for one scenario, one car, one driver, one event and F all use on the street or in real life. Not only that you wouldnt be able to sell it for use on the street in most of the world.


MS

 

[TrackRat]

More proof of driver error, not a vehicle defect, that resulted in a Prius crash.

http://www.msnbc.msn.com/id/35936650/ns/business-autos/