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Another Sudden Acceleration

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

  1. Omnomynous

    Omnomynous Member

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    @wk057, thanks for that. Very reassuring.
     
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  2. Dithermaster

    Dithermaster Member

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    This is exactly what others have said: temporary lack of deceleration. It's a brief period when the car realizes the tires are slipping during regen, removes regen, and then applies friction brakes, but not as seamlessly as usual. I've experienced it personally in three cars: 2006 Prius which did it frequently. 2012 Volt which did it sometimes and for a shorter time. 2013 Tesla Model S P85+: does it very rarely and very short time (almost not noticeable).
     
  3. sharpgator

    sharpgator Member

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    I have 3 places where I have this happen to me routinely. They all have the following characteristics:

    1) Downhill
    2) Bumpy
    3) Near terminal braking

    I’ve been over these spots hundreds of times and it happens every time unless I plan ahead and go even slower. However, the problem went away 2 software updates ago.
     
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  4. PunchIT

    PunchIT Member

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    I had the same experience in a Ford Fusion loaner Tesla gave me. It sure was startling. It seemed like there was a lag when mechanical brakes take over from regenerative braking. For a moment there is no braking!
     
  5. immolated

    immolated Member

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    #45 immolated, Jun 27, 2019
    Last edited: Jun 27, 2019
    This is wrong, I've used creep for 3 years. Taking your foot off engages normal regen identically to no creep mode down until ~3mph. Then you stay at ~3mph. Leaving creep on is safer (especially for reversing), because you can tell what gear the car is in before committing to the accelerator and potentially panic pressing it. You can also do most reverses (like leaving your garage) without even touching the accelerator, which also eliminates the opportunity for mistakes. I've suggested multiple times that tesla should enable reverse-only creep by default. Would eliminate every single driving into the house incident.
     
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  6. Omnomynous

    Omnomynous Member

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    Yeah, thats how mine behaves. Regen starts as you ease off the accelerator so you slow down with your foot off both pedals until you get down to creep speed.
     
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  7. Tam

    Tam Well-Known Member

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    I drove ICE for over 40 years so I hate creep because each time I took off my brake, it would just creep up!

    So as soon as I got Tesla in 2012, I never used it again until today.

    You are right that creep is for low speed only and it does not affect regen at normal speed.

    My creep speed is about 6 MPH which is too high when I expect my car to stay at zero MPH.

    Without creep, my Tesla would automatically activate a brake hold when I press the brake pedal slightly harder.

    With creep, I could not activate a brake hold whether it's automatically or manually. That is very strange.

    That means, with creep, I need to constantly apply the brake which can cause brake fatigue for me so I would slightly ease it off and it accidentally moved forward because there is no automatically a brake hold.

    So, this is what I find:

    Creep is good for those who don't want to push on the accelerator because the car would automatically accelerate to 6MPH by not pressing on the accelerator but just by releasing the brake.

    Non-creep is good for those who don't want automatic acceleration to 6MPH when the accelerator is not pushed because they want to manually push the accelerator in order to get acceleration.
     
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  8. Lerxt

    Lerxt Active Member

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    Do you use separate feet for the accelerator and brake?
     
  9. rohan3au

    rohan3au Member

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    I have this exact issue, I've tried raising it with both Tesla and the community on several occasions over the past 18 months with everyone suggesting I'm crazy or doing something wrong.
     
  10. Dr. J

    Dr. J Member

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    I've used both creep & no-creep modes. I have to push much harder in creep mode to get a brake hold. You have to mash it hard.

    Your experience of 6 MPH creep speed is much closer to mine than the reported 3 MPH. Different models may behave differently, I suppose.
     
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  11. MorrisonHiker

    MorrisonHiker S 100D 2019.32.2.2

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    Just push the brake pedal in a little more. It's not that much effort. I use it at almost every traffic light.
     
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  12. 3PHASE

    3PHASE 3PHASE

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    I've experienced an acceleration feeling in a Ford Fusion Energi when applying the brakes and going over a bump in the road. Feels like the car is lurching forward. People tell me this is more of an antilock braking thing.
     
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  13. Omnomynous

    Omnomynous Member

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    @Tam @Dr. J Could be that there's a creep adjustment/alignment that varies. My creep peaks at about 2mph (will do a sanity check later), so for me its only ever active for a second or two before I am on the gas pedal. Have not noticed a difference in how the brakes behave at all, but it is very interesting that you do. So many things to test. I'd seriously pay for whatever HW upgrade would give me live access to the logs. Not even for my regen issue, just to scratch the itch. It kills me as a dev that my favorite technical obsession won't share data with me.
     
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  14. wk057

    wk057 Senior Tinkerer

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    Creep is enabling a constant torque, not speed... just like in an auto trans ICE. So, you can creep at higher speeds downhill than uphill... with a flat ground number of about 4-6 MPH on all of the S/3/X vehicles I've been in and tried creep on.

    This is especially obvious in EV conversions with lighter vehicles, as the creep torque can accelerate them significantly, although I believe creep speed is capped at 12 MPH.
     
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  15. MrABRanch

    MrABRanch Member

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    I had a event happen recently, first time, pulled over in parking lot to let family into car, car was in 'hold' mode and beeping warnings because doors were open, but it was for a few seconds so I didn't bother to put it into park, as soon as doors were closed and I put the car into drive and 'probably' removed my foot from the break, it lurched forward, a lurch, then went back down to zero, I sat with my feet off everything and in a bit of surprise, no creep mode on. I carried on my trip without incident, this only ever happened once.

    Btw I've had weird accelerations and breaking and such on autopilot, or adaptive cruise control, it regen brakes sometimes when nothing in my lane has changed but I'm passing a car/truck. And sometimes it accelerates at inopportune times, which I override with the brake, which disengages ACC, I can't recall why it did it, I think between cars changing lanes, me coming off a highway, or adjusting to a set speed, it's a surprise but not the same thing as sudden acceleration events talked about here.
     
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  16. Omnomynous

    Omnomynous Member

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    I have seen that, too. Often right after its turned on, it goes like a frat boy even when there's a car close in front. Always reminds me that until the Singularity, we are technically driving the car even on AP.
     
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  17. Joer293

    Joer293 MODEL X P100DL

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    I noticed those improvements. My pre AP 2013 p85 had the unexpected lurch forward on the second driveunit. I had the G sensor in my dashcam to show the 2-3mph lurch. Service center guessed it was sensor noise or firmware bug. Disabling creep temporarily fixed it. About the time “creep” was deleted from firmware and customers complained enough to get it back it was resolved. The first drive unit had an unexpected lurch and Klunk but only in reverse. That was eventually deemed a manufacture defect, but when I first drove the car, they thought a firmware update would resolve.

    My 2016 X with AP1.5 never had those lurch issues. But every AP1 Tesla I’ve driven has a couple reproducible unexpected acceleration scenarios, That are technically “expected”, just undesirable behavior. All during AP.
    1. False speed limit recognition. Picks HOT/hov limit, not local lane limit. Driver must pay attention.
    2. High visibility emergency vehicles, the kind completely covered with seizure inducing reflective tape and the dangling snow chains, blinding all the sensors like a solar flare would. AP1 sees noise temporarily , and can’t decide if it’s echos and to accelerate or keep its distance.
    3. MD State police following way too close with specific gear radio/radar in use. Causes AP to ping pong in the lane and have difficulty maintaining speed within 2-3mph. I tested a couple times, and the SC reported the car logs see a really noisy environment. The city, county and Fed radio gear does not cause this interference. With the pending state upgrade to FirstNet radios, and advanced radar that should be resolved.
    4. The “crap autopilot was still on” moments. Some interstate highways have illogically low AP speed restrictions set by Tesla. (10mph or 35, with > 70+mph traffic speed) driving for miles with the accelerator pressed during AP steering, leads to forgetting AP set cruise speed will return once the unknown Tesla speed restriction zone ends. This usually happens when I let off the accelerator to allow someone to cut in front, and the car races to block them. Resulting in me getting cursed at by the guy I was attempting to be nice too.

    I’m sure AP2/3 hw is better equipped to resolve all of these issues. The SC did upgrade my front radar, claimed a voltage issue, which resolved most unexpected braking issues and helped reduce the emergency vehicle scenarios.
     
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  18. Tam

    Tam Well-Known Member

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    Wow! I literally have to push it much harder so no wonder I thought there's no brake holder in creep mode. I feel like I could break the brake!

    That's quite a contrast to activate brake hold in non-creep and creep mode!

    Thanks @Dr. J & @MorrisonHiker for the tip on how to get a brake hold in creep mode.
     
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  19. Tam

    Tam Well-Known Member

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    All S / X / and 3 can go to TACC from standing still.

    But Model 3 owners might experience it more because with the S and X, the TACC stalk is on the left opposite from the gear stalk while Model 3 TACC stalk is the same gear stalk.

    From standing still or very slow speed which normally is not eligible for TACC because of being under 18MPH but if there's a car in front, TACC can be activated from the speed or zero.

    Since Model 3 owners can swipe the gear stalk quickly to drive and might repeat it again to make sure it goes to drive gear, but the second action actually activates TACC if there's a car in front.
     
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  20. MrABRanch

    MrABRanch Member

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    Thanks that makes sense, and I've put it in TACC accidentally before, maybe it saw other cars in the parking lot, thinking about it this is probably what happened, as I was in 'H' mode, which is still drive, I then without thinking set it to 'D' which would have started TACC as it was already in 'D' - TACC saw cars started accelerating then stopped.
    Tbh it's a bad design compromise combining gear stalk with autopilot stalk, it's way too easy to unintentionally go into a autopilot setting, better that they spent the extra on another stalk than save a few $$ and have even 1 incident due to accidentally setting it into the wrong mode.
     

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