Something Doesn't Add Up

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By now, we are all familiar with the tale of the runaway Prius in the San Diego.

All along, I have personally known that the Prius has a throttle override feature, so the story did not add up to me. Sure enough, Edmunds has a long-term clunker 2004 Prius in their fleet and their auto engineer decided to do a test.

http://blogs.insideline.com/roadtests/20...k-throttle.html

The car went into neutral just fine, the engine goes to idle if you tried to stop the car and floor the throttle at the same time, etc.

So what's the problem?
 
It's amazing how he was able to bring it to a stop once the fuzz pulled along side and yelled at him with the PA. Maybe the next time my PC is acting up I'll call 911 instead of the corporate helpdesk. Just the cop's presence made all those bugs and sticky pedals shape up.
 
He had recently filed for bankruptcy and was actually leasing his car. It was the only thing he still owned after the case. He's flat broke. He said he panicked.
 
Originally Posted By: calvin1
It's amazing how he was able to bring it to a stop once the fuzz pulled along side and yelled at him with the PA. Maybe the next time my PC is acting up I'll call 911 instead of the corporate helpdesk. Just the cop's presence made all those bugs and sticky pedals shape up.


On the news it said the officer used his car in front of the prius to help stop it.

Software, or hardware could still have a design problem. Now days with the removal of lead solder, the newer lead free solder joints are prone to growing whiskers that connect to adjacent traces. This can happen at very small connections and cause intermittent or continuous failures. This problem has already disabled multi-million dollar satellites. What is to prevent it from causing failures in automotive electronics.

The demand that all vehicles have a brake override is not enough. If the break override in done electronically a hardware, and possibly a software problem could still cause a run-away.

What is required is a mechanical throttle plate in series with the intake air flow of the engine that is connected to the brake through mechanical means, or if electrical all parts of its circuitry must be independent of the engine control, and a watch dog subroutine on the engine should monitor this function for failure, and do a safe shut-down if it fails.
 
Originally Posted By: JimPghPA


On the news it said the officer used his car in front of the prius to help stop it.



Later reports clarified that the cop didn't use his car to get the Prius stopped. He just parked his cruiser in front of it after they got it off the road, blocking it.
 
When I read the story I got the impression that the police car parked in front of the car after it stopped on its own as precaution against another bout of unintended acceleration.

There will likely be a quiet follow-up story. It may well be that Toyota was unfairly blamed in this incident. If that's the case, it could help Toyota in the long run. They could imply that most incidents were driver mistakes or deliberate fraud.
 
Originally Posted By: JimPghPA
Now days with the removal of lead solder, the newer lead free solder joints are prone to growing whiskers that connect to adjacent traces. This can happen at very small connections and cause intermittent or continuous failures. This problem has already disabled multi-million dollar satellites. What is to prevent it from causing failures in automotive electronics.



That's what I was thinking when Toyota was attempting to defend against the claims of that Professor in Illinois. They said that the short circuits he was creating would never happen in the field. Right away I thought of tin whiskers. A whisker could create a short, then heat up, vaporize and disappear, leaving no evidence later when the circuit is examined.

Just a possibility.
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Originally Posted By: JimPghPA
Software, or hardware could still have a design problem. Now days with the removal of lead solder, the newer lead free solder joints are prone to growing whiskers that connect to adjacent traces. This can happen at very small connections and cause intermittent or continuous failures. This problem has already disabled multi-million dollar satellites. What is to prevent it from causing failures in automotive electronics.

The demand that all vehicles have a brake override is not enough. If the break override in done electronically a hardware, and possibly a software problem could still cause a run-away.

What is required is a mechanical throttle plate in series with the intake air flow of the engine that is connected to the brake through mechanical means, or if electrical all parts of its circuitry must be independent of the engine control, and a watch dog subroutine on the engine should monitor this function for failure, and do a safe shut-down if it fails.


What is required is a hard wired power off circuit with a big red button in the dashboard to trip the vehicle, rather than relying on telling a computer to do your wishes.

Personally, I feel that the specifics of this case are impossible.

Vehicle has a standard hydraulic braking system, that can stop the car. When you panic stop, you drive the pedal past the regeneative section of it's travel, and on to a good old hydraulic four wheel disk arrangement.

To get runaway like this, you need multiple systems failures.

Stuck/faulty pedal (say 1:1000 chance for argument's sake, but due to the number of miles on Prius', it's obviously way lower than that)
Motor Generator 1 controller faulty (say 1:1000 again).
Motor Generator 2 controller faulty (say 1:1000 again).
Brake over-ride faulty (say 1:1000).

Chances of all 4 failing in the same car at the same time 1:1000x1000x1000x1000...1 in a trillion.

And all failing into the same state ?

Plus the brakes failing over the top of that, and the fact that after reasonably heavy full throttle acceleration up a steep hill for 2 mins or so, there is no battery assist, and the thing can't get out of it's own way, let alone 140km/hr.

If the car genuinely had the set of failures that would lead to this event, this guy needs to buy a lottery ticket.
 
Originally Posted By: LT4 Vette
Many Toyota owners are now trying to cash in with a lawsuit

Actually, many lawyers are trying to cash in on Toyota owners with lawsuits. The only surprising thing about this is the lack of cheesy late-night "Have you been the victim of a runaway Toyota vehicle? CALL NOW to speak with a runaway Toyota specialist!" I 'spose that is just a matter of time now...
 
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You can not just shut down an engine, if power steering, and or power brake are run from it. If power steering and or power brake go to no engine power situation, sooner or later someone will get in a serious crash because of it.

You must make the engine go to idle. A brake activated throttle plate that restricts the air flow to idle (or high idle, enough that the engine would not stall, but brake could over-ride) is what is required. Then you must also include a watch dog progrom in the engine control that senses that this system is working properly, and refuses to go above idle if it is not.
 
Originally Posted By: Mustang_Cougar
Originally Posted By: LT4 Vette
Many Toyota owners are now trying to cash in with a lawsuit

Actually, many lawyers are trying to cash in on Toyota owners with lawsuits. The only surprising thing about this is the lack of cheesy late-night "Have you been the victim of a runaway Toyota vehicle? CALL NOW to speak with a runaway Toyota specialist!" I 'spose that is just a matter of time now...



I actually did see an ad like that and during prime time a week or two ago. I haven't seen anothr since. It was just like the cheesy lawsuit ads for asbestos or drugs. Not that being harmed by prescription drugs or asbestos is cheesy.
 
Originally Posted By: JimPghPA
You can not just shut down an engine, if power steering, and or power brake are run from it. If power steering and or power brake go to no engine power situation, sooner or later someone will get in a serious crash because of it.


Give me one good reason that any person who is elligible to be driving couldn't have enough muscle to pull over a power assisted steering car, just once.

If it's such a critical thing, then you certainly can't trust a simple rubber V-belt to drive it.

As to power brakes, vaccum boosters have a number of stops in them with the engine off. While pushing a car around your yard, you are still power assisted for a good measure.

And once that's gone, the brakes still work, just need a shove.
 
Yes,they are power assisted steering,and power assisted brakes,the steering and braking systems are still there,ready to be used with just a little more muscle....perhaps that is what's lacking.
 
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