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Another Sudden Acceleration

Discussion in 'Model S' started by Omnomynous, Jun 25, 2019.

  1. Silicon Desert

    Silicon Desert Active Member

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    Oh I don't think I would like that. I'd have to try it to see how it feels and works.
     
  2. Silicon Desert

    Silicon Desert Active Member

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    #102 Silicon Desert, Jul 18, 2019
    Last edited: Jul 18, 2019
    As with other comments, I guess it depends on the person. That has never been an issue with me. In fact, I have better tactful feel with bare feet. Hey, I'm a hillbilly so I've done it a lot :) It used to be illegal to drive barefoot long ago where I grew up, but they changed the law.
     
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  3. immolated

    immolated Member

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    Please do follow through with the logs. It's not that we "want" it to be human error, it's just that history has proven that not a single person's log data actually showed they had the brake pressed when they swore they did. So you would be the first.

    Honestly if your logs show your car accelerated without the accelerator pressed, I think that would be great so Tesla could acknowledge and fix what would be a major critical flaw. So I'm rooting for you to be right, but expecting the reality of human error.
     
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  4. Oldschool496

    Oldschool496 Member

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    Like one has said here, if your sensors both failed and had truly leakage voltage (of the almost a million cars I think now I have lost track of the actual number). Your car may be number two if this report was found to be true.

    I did not read the whole thing just the conclusion.

    I too have long thought these things are all electrical, have faults of there own. In reality none of that may matter.

    But if you had your foot firmly planted on the brake and you could not control your car, then sir your the fault, you and only you. Sensors, motors, batteries, tires, brakes will not change that fact ever.

    Why?

    Its a legal issue really.

    Because you are in charge of the movement of that vehicle and if you plant your foot firmly on that brake, no ICE or electric motor and can overcome that "Braking Force" you are applying.

    I can tell you if not firmly planted and you hit the accelerator a little, well you have a similar result to yours, 99.9999999999999% of the time.

    No doubt in anyones mind here.

    So lets all agree to disagree with you for now till you bring it. Please bring it.
     
    • Disagree x 1
  5. TexLaw

    TexLaw Member

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    I was going to bring that up. I have the same sensation when my regen is limited due to cold or high SOC. I lift off the accelerator, and the car feels like it speeds up, but that's only because the car is not slowing down when I expect it to.

    That's not to say that something isn't awry with your regen.
     
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  6. Mark_T

    Mark_T Member

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    Even if it is regen related the same answer applies, foot firmly on the brake will halt the car.
     
  7. SucreTease

    SucreTease Teslarian

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  8. Silicon Desert

    Silicon Desert Active Member

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    #108 Silicon Desert, Jul 19, 2019
    Last edited: Jul 19, 2019
    When I read that line I was pretty sure it was wrong based on some prior experience with that. So here is another viewpoint...

    Not All Unintended Acceleration Is Driver Error

    Edit: I forgot to say, yes, I know the Tesla is different and likely will allow the brake to over-ride the accelerator, so not trying to compare apples to oranges. Fortunately the Tesla is designed differently from older ICE cars. What I am trying to point out is that on ICE cars, it is not always true that pressing the brake will over-ride the motion.
     
  9. SucreTease

    SucreTease Teslarian

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    I don't want to sidetrack the topic here, but is there someone here who can explain how lifting one's foot from the brake during a wide-open throttle causes progressive loss of braking power each time the pedal is reapplied?
     
  10. Electric700

    Electric700 Active Member

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    You can put your car into neutral if you can't get it to slow down, but I believe you should still keep your foot on the brake while doing so. If that doesn't work, try powering it off.

    Sometimes the floor mat or even something like a bottle that fell and got under the brake can cause deceleration or acceleration issues, so you have to always be cautious.
     
  11. Oldschool496

    Oldschool496 Member

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    WE are moving off topic though widely here now with ICE also thrown in and if you watch the video at the end they just say don't pump the pedal to not lose the vacuum assist the vehicle will be overcome by braking action.

    Yes, if the return spring breaks on the carb/injection system, there is a problem. The brakes though are designed to overpower any problem to the best of my knowledge. Now if your not maintaining and the brakes don't work properly or the return spring breaks on the carb, well thats something altogether different, which points right back to the user liability, insurance and whole host of guess what, its my, our fault and I own it.

    Thats where we are going here. Rarely people want to own it anymore. Its always returning the goods or no fault of mine type of issue it must always be the fault of others or its broken, I am so sure of myself, I'm never at fault.


    As to Toyota to the best of my knowledge again it was the matts that caused the problem. Lets not go there, because the matts in a Tesla Model S anyway are well shall I say ready for liability issues of there own. Not a problem though because I have the brakes to depend on.
     
  12. ktkemp

    ktkemp New Member

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    The movement of the pistons in an ICE create a vacuum in the intake manifold under most operating circumstances. There is a tube that runs from the manifold to the brake booster which uses the engine's manifold vacuum to add pressure to the brake master cylinder greater than what the driver pushing on the pedal can supply. This booster works by opening a valve to the atmosphere when the brake pedal is pressed so the pressure on either side of a diaphragm is different, and the diaphragm helps push the brakes.

    At wide open throttle, this vacuum pressure drops because the throttle is essentially a hole between the manifold and the outside atmosphere, so when it's "wide open" the pressure equalizes.

    Without this vacuum pressure, the brake booster does almost nothing and the pressure required to operate the brakes may be more than what the driver can supply by him or herself. Pumping the brakes allows the pedal to come back up, after which the driver may not be able to push it down again. It also opens and closes the booster's valve, which may hasten the equalization of pressure on the diaphragm.
     
    • Informative x 1
  13. Oldschool496

    Oldschool496 Member

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    Very well said and the best description of that act I have ever read, so loss of vacuum under hard accel results in hard or very hard braking.
     
  14. paolodapaesan

    paolodapaesan Member

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    I do tend to agree with your legal interpretation. I am not naive enough to think that somehow Tesla will admit their may have been an issue. Their liability is enormous to admit to even one case. If I hit the accelerator a little, I would have been stopped by the cement parking block and curb. It was full on ludicrous launch. Does anyone think it is likely that I was jamming the brakes while parking?
     
  15. paolodapaesan

    paolodapaesan Member

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    I have asked Tesla for Data Logs, and it has been radio silence. They were checking with legal before sending to me....
     
  16. jdw

    jdw Supporting Member

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    #116 jdw, Jul 19, 2019
    Last edited: Jul 19, 2019
    What is missing from the paper and its conclusions, as far as I can see, is firstly any information about what the brake pedal was doing while these acceleration spikes were happening. Secondly, if you press both pedals, only the brake will work or at worst, minor acceleration for a short time. But is the sensor/logic/circuit that controls "two pedals pressed" before or after the acceleration or pedal logic? I would think it would be after, so that if there was some failure as described in the paper, that the command to accelerate (wherever it came from) would ultimately be ignored or overridden by the brake pedal being depressed.

    If you could actually accelerate while holding the brake, that would be an "interesting" design choice that we likely would have heard about by now.
     
  17. paolodapaesan

    paolodapaesan Member

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    I am an electrical engineer and somewhat noted scientist. This will be investigated to the fullest!
     
  18. SO16

    SO16 Active Member

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    Please let us know your findings.
     
  19. Dithermaster

    Dithermaster Member

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    I read this PDF. While it's in the form of a fancy report, it's a lot of speculation, based on a handful of numbers read over the phone. That's not the same as having data from the car.

    Also (and this needs confirmation from someone who knows for sure) the potentiometers in the TPS sensor are wired in reverse of each other, so as one wipes from GND to VDC, the other wipes from VDC to GND. So loss of VDC would not cause a higher reading from both sensors, it would cause a higher reading from one and a lower reading from the other.

    If bad readings from the TPS are causing UA events, I'd hope Tesla would see a pattern in the detailed logs they pull, and would immediately issue a recall to fix it (no responsible automaker would sit on that).
     
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  20. SO16

    SO16 Active Member

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    A couple people here gave some interesting insight. Especially “sippiecup”. Albeit the name doesn’t really instill confidence...haha.

    Tesla’s Sudden Acceleration Log Data–What It Shows : RealTesla
     

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