Vivisection of bad Prius

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Old 03-09-2010, 10:50 AM
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Default Vivisection of bad Prius

What do ya'll think they'll find?

http://www.businessweek.com/news/201...gas-pedal.html

March 9 (Bloomberg) -- Toyota Motor Corp., struggling to regain a reputation for quality after unintended acceleration forced millions of vehicle recalls, will investigate a report in California of a Prius hybrid car that sped out of control.
The Japanese carmaker learned that the California Highway Patrol was dispatched after a Prius driver in San Diego County called 911 to report a stuck accelerator pedal, Toyota said yesterday on its Web site. A patrol officer helped coach the driver to stop the car, the motorist told reporters.
“I was on the brakes pretty healthy,” James Sikes, the Prius driver, said on NBC after telling news organizations his car reached speeds of 90 mph on U.S. Interstate 8 outside San Diego. “It wasn’t stopping. It wasn’t doing anything to it. It just kept speeding up.”
Toyota, the world’s biggest automaker, has recalled about 8 million vehicles, including top-selling Camry and Corolla cars, to repair defects that may cause unintended acceleration. The carmaker held a press briefing at its U.S. headquarters in Torrance, California, yesterday to rebut a test of its electronic throttle control system cited in testimony to Congress as a possible cause for the flaw.
Sikes told cable channel CNN the accelerator was stuck and wouldn’t move even when he tried to lift it by hand. The car failed to slow down even after Sikes called 911 and followed instructions to get the car to stop.
‘Won’t Drive Car’
A California Highway Patrol officer, alerted by emergency dispatchers, caught up to Sikes and, using his public-address system, asked him to apply the emergency brake and brake pedal at the same time. That worked to slow the car to 50 mph. Then Sikes was able to turn off the ignition, he told CNN.
The responding officer was quoted on NBC saying he saw Sikes’s brake lights were on and smelled that the pads were being applied.
“I won’t drive that car again, period,” Sikes said on NBC.
The model in San Diego “appears to be a second-generation Prius” and not the 2010 model, said Brian Lyons, a spokesman for the automaker. Three Toyota technicians are prepared to inspect the vehicle once it is located, he said.
Sikes had recently serviced the Prius at a local dealer and was informed it wasn’t part of a recall, he told NBC.
Toyota in November recalled 2004 through 2009 model-year Prius hybrids to reshape accelerator pedals that the company said could be entrapped by floor mats. The 2010 model has also been recalled so its braking software could be adjusted.
Further Research
David Gilbert, the Southern Illinois University professor whose research Toyota disputed, said yesterday that he will visit the engineering firm hired by Toyota next week to discuss its methods and procedures.
“I am committed to working with industry, government and other interested parties and hope to provide more conclusive opinions and input as more research and analysis is completed,” Gilbert said in a statement.
Safety Research & Strategies Inc., which funded Gilbert’s test, said the findings show that Toyota is incorrect in asserting its electronics are infallible. Further study is needed, Sean Kane, president of the Rehoboth, Massachusetts- based group, said in an interview.
“While Toyota is out there showing the world it isn’t electronics, we’re going to continue to see incidents like the one in San Diego,” Kane said. “These problems aren’t going to go away for Toyota by saying they don’t exist.”
House Hearing
Safety Research’s clients include attorneys, engineering firms and automotive suppliers, according to its Web site.
The House Energy and Commerce Committee said today a March 11 hearing will focus on oversight of the National Highway Traffic Safety Administration, which can order automotive recalls.
Witnesses will include NHTSA Administrator David Strickland; Dave McCurdy, president and chief executive officer of the Alliance of Automobile Manufacturers; and Joan Claybrook, a former NHTSA administrator.
--Editors: Steve Geimann, Larry Liebert
 
  #2  
Old 03-09-2010, 11:17 AM
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Default Re: Vivisection of bad Prius

This is a curious case. It sounds like the brake pedal stuck a la the failure in North American-made Toyotas, but this car would have the Denso pedals. Could this case be an electronic or software failure?

Second, a few weeks ago somebody on these forums posted a notice from Toyota indicating that their hybrids had some form of brake override already (it didn't say what form). Why didn't that work in this case?

Third, the driver finally shut off his engine (he tried more than once, probably not knowing about the 3-second hold requirement when the car is moving). Wouldn't putting it in neutral be the better alternative? It may be hard to think clearly in a panicky situation like that, but this is well-publicized issue and I hope anyone would be prepared for such an event. Maybe some practice runs shifting into neutral while the car is moving would be in order for all of us.

It occurs to me that the elusiveness of these problems is the result of the long-tail phenomenon. Of how many millions of Toyotas on the road, how many dozens or hundreds have had these problems (excluding the floor mats which I think are by far the most common cause of sudden acceleration), after driving how many thousand hours? How many thousands of cars would Toyota therefore have to test, for how many thousands of hours each, to reproduce a given problem once? If there are three separate causes -- floor mats very common (it's happened to me), sticky pedals far less common, and electronic or software failures probably even less common if they do happen at all -- it's easy to see how difficult it is to peel that onion, or more significantly, to know when you've finished peeling it.
 
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Old 03-09-2010, 11:36 AM
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Default Re: Vivisection of bad Prius

I just have to wonder what it is that triggers the rapid acceleration?

I have a 2004 Prius II and haven't had any of the issues associated with this. I know that my ABS brakes have done some odd pumping on icy roads, but i honestly expect that on such a variable surface. I use the original mats, along with rubber ones molded to the car, with the cleats to hold the mats in place, so I have never had mat issues.
 
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Old 03-09-2010, 12:15 PM
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Default Re: Vivisection of bad Prius

No mention of the driver pressing the power button for 3+ seconds to stop the HSD or even trying to shift into neutral. If he didn't try either I wonder why?. It sounds like the traditional brakes couldn't stop the car but the emergency brake did? Again makes no sense. I guess I won't know what goes through one's mind until it happens to me. Hopefully it won't.
 
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Old 03-09-2010, 01:43 PM
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Default Re: Vivisection of bad Prius

Hybrid brake systems usually have a pedal force simulation to give the driver feedback like a "normal" vehicle. This way you feel like you are doing the braking but the hybrid system is.

It is possible but EXTREMELY rare to have a hard pedal and no hydraulic actuation. In this case the old school mechanical parking brake would still apply.

And produce the hot brake pad smell the officer spoke of.
 
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Old 03-09-2010, 04:28 PM
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Default Re: Vivisection of bad Prius

Originally Posted by rmoore
This is a curious case. It sounds like the brake pedal stuck a la the failure in North American-made Toyotas, but this car would have the Denso pedals. Could this case be an electronic or software failure?
D'oh, I meant "accelerator pedal" of course.
 
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Old 03-09-2010, 04:35 PM
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Default Re: Vivisection of bad Prius

Originally Posted by Hillbilly_Hybrid
This way you feel like you are doing the braking but the hybrid system is.
It is possible but EXTREMELY rare to have a hard pedal and no hydraulic actuation. In this case the old school mechanical parking brake would still apply.
My understanding is that hard pressure on the brake pedal will cause the friction brakes to engage in addition to regenerative braking. And also that at high speeds you can lose braking power because of loss of engine vacuum.

And produce the hot brake pad smell the officer spoke of.
I thought the officer smelled the brakes when he first got there, not after he told the driver to apply the emergency brake.

I'm really curious to hear what the result of the investigation will be.
 
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Old 03-09-2010, 04:46 PM
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Default Re: Vivisection of bad Prius

Originally Posted by joeumama
The carmaker held a press briefing at its U.S. headquarters in Torrance, California, yesterday to rebut a test of its electronic throttle control system cited in testimony to Congress as a possible cause for the flaw.
(snip)
David Gilbert, the Southern Illinois University professor whose research Toyota disputed, said yesterday that he will visit the engineering firm hired by Toyota next week to discuss its methods and procedures.
(snip)
Safety Research & Strategies Inc., which funded Gilbert’s test, said the findings show that Toyota is incorrect in asserting its electronics are infallible.
Does anyone know what Gilbert did to supposedly reproduce the sudden acceleration? A TV news story I saw said that Toyota's response was that other manufacturers' cars failed the same test. TV news being in the sorry state it is, the story was very unenlightening. Guess it's off to Google-land, now that I know his name.

Also, did Toyota actually claim its electronics were "infallible"? That's not the same as saying "not at fault". "Infallible" is not something a sane designer or manufacturer would claim for any product.
 
  #9  
Old 03-09-2010, 04:59 PM
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Default Re: Vivisection of bad Prius

Originally Posted by rmoore
Does anyone know what Gilbert did to supposedly reproduce the sudden acceleration? A TV news story I saw said that Toyota's response was that other manufacturers' cars failed the same test. TV news being in the sorry state it is, the story was very unenlightening. Guess it's off to Google-land, now that I know his name.
And I'm back, having found my answer:
http://www.autoblog.com/2010/03/08/t...-demonstratio/

In short (pun not intended), Gilbert created an unlikely-in-the-real-world fault condition that does not cause an error code.
 
  #10  
Old 03-10-2010, 06:52 AM
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Default Re: Vivisection of bad Prius

Originally Posted by rmoore
...And also that at high speeds you can lose braking power because of loss of engine vacuum....
Since the ICE isn't running in many conditions the hybrid brakes don't depend on engine vacuum.
 


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