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bev2001 03-02-2012 08:30 AM

Sudden Uncalled-for Acceleration Santa Fe 2011 3.5 FWD
 
Has anyone experienced a sudden uncalled-for acceleration in a Santa Fe. My incident occurred while coasting to a stop with my foot on the brake pedal, maybe 5 kph. A surge in engine power I'm standing on the brake with all my force and end up with the front wheels on top of a concrete block. Yeah, I've heard the remarks ". . you pressed the wrong peddle buddy . . " and sympathetic noises from the dealership and the customary the diagnostics don't indicate any problem. One questions oneself but generally instinctively you are aware when you've made a blunder, I know I didn't. Its impossible to press the brake and accelerator at the same time.
I like my Santa Fe, 14,000 of terrific motoring but this incident. I checked Edmonds and I see Anyone experience Sudden Unintended Acceleration in a Santa Fe? - Car Forums - Edmunds
similar incidents.

NovaResource 03-02-2012 09:13 AM

Driver error

Toyota sudden acceleration report finds no electronic flaws - Feb. 8, 2011

Toyota's acceleration problem: Thousands of bad drivers? - The Week

Crash Data Suggest Driver Error in Toyota Accidents - WSJ.com

NovaResource 03-02-2012 09:49 AM

Here's a cool article from Car and Driver were they tested cars with the throttle to the floor and then tried stopping the car. All cars tested were able to stop with the throttle stuck all the way open:

How To Deal With Unintended Acceleration - Tech Dept. - Car and Driver


http://www.caranddriver.com/images/m...s-original.jpg

Lexus and Toyota models were stung recently by claims that faulty floor mats had jammed throttle pedals and were causing wide-open acceleration. Toyota has agreed to a largest-ever recall of 4.3 million vehicles (which could cost $250 million or more) to modify the gas pedals and remove unsecured or incompatible driver’s floor mats. Not since Audi was decimated by accusations of unintended acceleration in the late 1980s has the topic of runaway cars received so much media attention.

The furor began when an off-duty California Highway Patrolman crashed a loaner Lexus ES350 at high speed, killing himself, his wife and their daughter, and his brother-in-law. It was reported that someone, either the officer or his brother-in-law, called 9-1-1 moments before the crash, saying that the “accelerator is stuck . . . there’s no brake.”

Our focus here is not to question the validity of the “floor-mat” claims (some investigators have suggested that a faulty drive-by-wire system is to blame) but to present methods for coping with this heart-stopping situation and to investigate a Toyota’s relative performance during such an event. For our tests, we rounded up a disparate bunch: a V-6 Camry (a recalled vehicle), an Infiniti G37 convertible, and a hugely powerful 540-hp Roush Stage 3 Mustang.

Our tests were conducted at highway speeds, as the incident with the Lexus ES350 happened on an expressway, and in the lowest possible gear, as that's the worst-case scenario. Here is how to deal with a runaway car:

Hit the Brakes
Certainly the most natural reaction to a stuck-throttle emergency is to stomp on the brake pedal, possibly with both feet. And despite dramatic horsepower increases since C/D’s 1987 unintended-acceleration test of an Audi 5000, brakes by and large can still overpower and rein in an engine roaring under full throttle. With the Camry’s throttle pinned while going 70 mph, the brakes easily overcame all 268 horsepower straining against them and stopped the car in 190 feet—that’s a foot shorter than the performance of a Ford Taurus without any gas-pedal problems and just 16 feet longer than with the Camry’s throttle closed. From 100 mph, the stopping-distance differential was 88 feet—noticeable to be sure, but the car still slowed enthusiastically enough to impart a feeling of confidence. We also tried one go-for-broke run at 120 mph, and, even then, the car quickly decelerated to about 10 mph before the brakes got excessively hot and the car refused to decelerate any further. So even in the most extreme case, it should be possible to get a car’s speed down to a point where a resulting accident should be a low-speed and relatively minor event.

http://www.caranddriver.com/images/m...s-original.jpg

But Toyota could do better. Since the advent of electronic throttle control, many automakers have added software to program the throttle to close—and therefore cut power—when the brakes are applied. Cars from BMW, Chrysler, Nissan/Infiniti, Porsche, and Volkswagen/Audi have this feature, and that’s precisely why the G37 aced this test. Even with the throttle floored and the vehicle accelerating briskly, stabbing the brakes causes the engine’s power to fade almost immediately, and as a result, the Infiniti stops in a hurry. From speeds of 70 or even 100 mph, the difference in braking results between having a pinned throttle or not was fewer than 10 feet, which isn’t discernible to the average driver. As a result of the unintended-acceleration investigation, Toyota is adding this feature posthaste.

We included the powerful Roush Mustang to test—in the extreme—the theory that “brakes are stronger than the engine.” From 70 mph, the Roush’s brakes were still resolutely king even though a pinned throttle added 80 feet to its stopping distance. However, from 100 mph, it wasn’t clear from behind the wheel that the Mustang was going to stop. But after 903 feet—almost three times longer than normal—the 540-hp supercharged Roush finally did succumb, chugging to a stop in a puff of brake smoke.

Shift to Neutral or Park
This is your best option in an emergency. Neither the Camry’s nor the Infiniti’s automatic transmission showed any hesitancy to shift into neutral or park when accelerating at full tilt. (Automatics have a piece of hardware called a park pawl, which prevents the transmission from actually engaging park and locking the wheels at speed—it creates a disturbing grinding sound, but the car essentially coasts freely.) The Roush had a manual, so you’d simply depress the clutch. In either case, power is effectively kept from the wheels and the car will be able to brake with its usual undiminished vigor, engine racing or not.

Turn It Off
Switching off the ignition is a sure way to silence an engine, but it’s probably the least desirable action because it will also make the car more difficult to maneuver. It causes a loss of power-steering assist, plus it will cut off vacuum boost for the brakes. The new wrinkle here: the keyless, push-button start-and-stop systems in many vehicles. Owners need to be aware that these systems require a long press of the button to shut off power when the car is moving (so that an inadvertent touch of the button by the driver doesn’t kill the engine). Here, too, the Toyota was slightly behind the curve; the Infiniti’s engine shut down after a 2.5-second press of the button versus 3.3 seconds for the Camry. In an emergency, that would probably feel like an eternity. For some perspective, if a V-6 Camry’s throttle became stuck at 60 mph, the car would accelerate to nearly 80 mph before the engine would surrender.

Furthermore, short, frantic pressing of the Toyota’s start/stop button—the probable response in an emergency—does nothing, whereas the Infiniti kills the engine after three rapid-fire presses.

Conclusion
In the end, though, we found no major deficiencies with the Camry’s ability to defuse an unintended-acceleration situation. But the No. 1 automaker could learn a few lessons from the competition here—namely a throttle cutoff and a more responsive push-button ignition.

http://media.caranddriver.com/images...s-original.jpg


Bottom line, you said "I'm standing on the brake with all my force". If that were true you would have been able to stop. So my guess is you were standing on the throttle with all your force.

bev2001 03-03-2012 04:43 PM

Interesting article and reasonably sound reasoning.

The thing is my foot was on the brake slowing to a stop after turning off the main road and slowing from 40 kph down to 5 or 6 kph ready coasting to a stop. Maybe 5 or 6 feet from the stop. The only reason I didn't crash into the store was the braking and shifting to neutral.

Software is my profession and we are talking about human reaction time compared with a software invoked events, no question who's the winner. In my situation I believe I reacted to the surge in a second or two. Software diagnostics are only as good as the programmer's failure mode analysis and in my experience failure detection is at best rudimentary and subsequent recovery to normal functionality is the most bug prone practices in real-time code. I'd guess that there is little cross-checking of sensors and heuristic reasoning involved.

I'd like to experiment with my Santa Fe using similar tests performed on the vehicles in the article but special facilities are a problem. I'll investigate to see if there is a brake override on throttle demand, I don't believe there is.

Your response, " . . Bottom line, you said "I'm standing on the brake with all my force". If that were true you would have been able to stop. So my guess is you were standing on the throttle with all your force. . ", is entirely reasonable and that is the position that manufactures take since they know there is insufficient proof. That is until someone dies and they respond to any media investigation.

NovaResource 03-04-2012 10:30 AM


Originally Posted by bev2001 (Post 42084)
Your response, " . . Bottom line, you said "I'm standing on the brake with all my force". If that were true you would have been able to stop. So my guess is you were standing on the throttle with all your force. . ", is entirely reasonable and that is the position that manufactures take since they know there is insufficient proof. That is until someone dies and they respond to any media investigation.

People have died and investigations into the computer recording devices showed the throttle was at wide open and the brake was not on even when the driver believed they were on the brakes.

Read:
Crash Data Suggest Driver Error in Toyota Accidents - WSJ.com

One case studied by U.S. regulators involves Myrna Marseille of Kohler, Wis., who reported in March that her 2009 Toyota Camry accelerated out of control and crashed into a building.

Ms. Marseille said in an interview Tuesday that she was entering a parking space near a library when she heard the engine roar. "I looked down and my foot was still on the brake, so I did not have my foot on the gas pedal," she said.

Police in Sheboygan Falls, Wis., investigated and believe driver error was to blame, Chief Steven Riffel said Tuesday. He said surveillance video showed that the brake lights didn't illuminate until after the crash. But Mr. Riffel said that determination is preliminary and that his agency has turned over the investigation to NHTSA.

Based on the black box data, NHTSA investigators found that the brake was not engaged and the throttle was wide open, according to a person familiar with the matter.

Toyota's acceleration problem: Thousands of bad drivers? - The Week

What did the NHTSA find?
The federal safety agency looked at the "black boxes" in dozens of totaled Toyotas and Lexuses whose drivers blamed their crash on unresponsive brakes and runaway acceleration, and found that in nearly all cases the accelerator was at full throttle and the brakes weren't engaged at the time of the crash, The Wall Street Journal reports. That suggests the drivers mistakenly stepped on the gas when they meant to hit the brakes.
Bottom line: driver error

/Thread

bev2001 03-05-2012 02:43 PM

I hove no reason to dispute any these press reports.

My brakes worked fine, I stopped. I'm not trying to defend any action or my bad driving, implied, the braking stopped my forward momentum. I claim/believe that a spurious event perhaps from a sensor, throttle pedal position or throttle valve position. These according to my research are simplex, i.e., if any items in the loop fails its curtains. Simplex is not safe enough for drive-by-wire.

Similar design techniques, software, are used in aircraft fly-by-wire systems and they have triplex or duplex sensors voting algorithms and control software. Bottom line is in my opinion the software design focuses on functionality of automobile behaviour and not enough on failure modes of the devices it uses The other issue I believe is true that data collected persists for a finite period of time probable less than a few key turns.

Driver and Pilot is usually the findings when the discovery analysis cannot find the root cause.

bev2001 03-05-2012 02:47 PM

By the way; a good discussion lots information provided and food for thought.


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