TMC is an independent, primarily volunteer organization that relies on ad revenue to cover its operating costs. Please consider whitelisting TMC on your ad blocker and becoming a Supporting Member. For more info: Support TMC
Start a Discussionhttps://teslamotorsclub.com/tmc/tags/

Apply parking brake at speed - effect

Discussion in 'Model S: Driving Dynamics' started by EriCal, Nov 16, 2016.

  1. EriCal

    EriCal Member

    Joined:
    Mar 10, 2014
    Messages:
    15
    Location:
    SoCal
    My Wife and I practice a drill for the passenger to take control of the car in an emergency. We have the procedure worked out, and drilled, for the S7 but not yet for the Tesla. There are some questions:

    What is the effect/result of applying the parking brake at speed? Have you actually done it?

    Will the car allow one to shift into reverse at speed or is it blocked? It appears it would be very easy to select reverse when only neutral is wanted unless there is a block when the car is at speed.

    Tnx. Eric
     
  2. trils0n

    trils0n 2013 P85

    Joined:
    Feb 12, 2013
    Messages:
    1,411
    Location:
    SF Bay Area
    Believe you need to be less than 2mph (Forget the actual speed, but it is low) and have foot on brake to switch into reverse.
     
  3. EarlyAdopter

    EarlyAdopter Active Member

    Joined:
    Jun 24, 2012
    Messages:
    2,685
    Location:
    Redmond, WA
    I believe applying the Parking/Emergency brake at speed will bring the car down to a stop in a controlled, but expedient manner.

    This can be initiated through either the center console display button, or by holding down the parking button on the shift knob.
     
  4. brianman

    brianman Burrito Founder

    Joined:
    Nov 10, 2011
    Messages:
    16,120
    If you give proper warning, it might a be good thing to try on a test drive. #notmycar :p
     
    • Funny x 1
  5. scottm

    scottm Active Member

    Joined:
    Jun 13, 2014
    Messages:
    1,932
    Location:
    Canada
    #5 scottm, Nov 16, 2016
    Last edited: Nov 16, 2016
    Nope!

    You can be rolling at slow speed and flip between D and R without using the brake pedal and the car will take the command and respect your request. But only if your speed is low enough... (think crawling speed in a parking lot... ) I do this all the time.

    There is a certain speed threshold, that it you're traveling faster ... the D/R change will not take effect, and instead the car goes into N (rolling). The only way to get it out of N, even if the car comes to a complete rest on its own, is to press brake while making the direction selection you want. Just like you have to do getting the car out of Park.
     
    • Like x 1
  6. scottm

    scottm Active Member

    Joined:
    Jun 13, 2014
    Messages:
    1,932
    Location:
    Canada
    I'm game to try emergency braking using the park brake...

    My guess is the sucker will clamp down hard, possibly locking the rear wheels... but maybe uses ABS anti-locking type modulation...

    I will try both the center console, and the button on the stalk... see if they behave differently. It will be neat to try.

    I'll report back.
     
    • Like x 3
  7. Krugerrand

    Krugerrand Well-Known Member

    Joined:
    Jul 13, 2012
    Messages:
    5,394
    Location:
    California
    scottm is now either in the hospital getting fitted with a neck brace, or having his car towed to the local service center. :D
     
    • Funny x 2
  8. DJung

    DJung Member

    Joined:
    Feb 28, 2013
    Messages:
    375
    Location:
    Newport Beach, CA
    I did this accidentally once. I was driving home tired one day and tried to activate my windshield wiper fluid + wipers while going about 45 MPH. I pressed the button but nothing happened for about a second. Then the error chimes started ringing in the cabin and the car jerked and began to slow down rapidly. I quickly realized me error and let go of the button. I quickly hit the accelerator pedal to bring the car back up to speed and I never made the same mistake again. Thankfully nobody was behind me, but that was very embarassing :rolleyes:

    Also in 8.0, I believe they removed the E-Brake option from the controls menu on the main 17 inch display
     
  9. EriCal

    EriCal Member

    Joined:
    Mar 10, 2014
    Messages:
    15
    Location:
    SoCal
    Have learned a few things. The car will not shift into reverse at speed and, pressing the "park" button at speed will apply the brakes moderately. The braking force increased significantly when the accelerator is released.

    Our procedure, and the one we practice is: All with the left hand, passenger presses the flasher button, shifts to neutral, takes the steering wheel and prepares to press the park button with the thumb of the left hand to bring the car to a halt.

    We tend to oversteer when steering from the right seat with the left hand so that will take some practice, but, in general we think we have a procedure established.

    We have a very similar procedure for the S7 but the parking brake on it requires great caution.

    Thanks all for your input, it was very helpful.
     
    • Like x 1
    • Love x 1
  10. AudubonB

    AudubonB Mild-mannered Moderator Lord Vetinari*

    Joined:
    Mar 24, 2013
    Messages:
    5,389
    What if you just lift your weight off the seat? At what speed does that no longer activate the OhNO!
     
  11. scottm

    scottm Active Member

    Joined:
    Jun 13, 2014
    Messages:
    1,932
    Location:
    Canada
    #11 scottm, Nov 19, 2016
    Last edited: Nov 19, 2016
    I'm fine!..

    I did this at a few different speeds and surface types, couldn't lock up the tires. :( No power turns for me. Pressing and Holding the Park button will apply the rear parking brake after a second or two of continuous holding. Pressing for less time does nothing. Once it starts braking, if you let go of the button it will let go of the brake too. So you gotta continue to hold it if you really need a stop. Feels and sounds like it's applying the brake with a modulated force - so it doesn't lock up. As the car slows the force increases and hauls the car down to zero quite nicely. It feels like really strong regen.

    I didn't pay attention to what I was doing with the pedals at the same time, or what was going on with the power bar on the IC. Because I was kinda nerved out. And I'm curious about that now... so I'm going to do some more and report back some more details.

    I'm going to do this again...
    while holding the go pedal at a certain power being applied position... I want to see if the power bar stays orange or if the car knows enough to cut power and use regen at the same time the parking brake is doing its thing, as you'd expect for more 'normal like' braking.

    and do it again with my foot off the go pedal, so the car is already in regen/deceleration ... this is kinda what I think I did first time around

    I'm also going to pay attention to what 'gear' the car goes into when releasing the Park button before the car actually stops. I *think* it slips into Neutral, but may stay in Drive, but I'll confirm.

    And if I'm really remembering things, I'll have a look and see what the rear brake lights do on the car. See if they come on.

    Someone said the e-brake button is gone from the center console UI, so I'll do all my experiments on the Park button .... it always seemed goofy to me to put an emergency function the center UI.. humm dee dum .. car controls, driving, settings, ..where the hell is it ... as car launches over cliff... FOUND IT!
     
    • Like x 2
    • Funny x 1
  12. scottm

    scottm Active Member

    Joined:
    Jun 13, 2014
    Messages:
    1,932
    Location:
    Canada
    OK, more tries, more detail... maybe you'll find some of this interesting?

    I encourage everyone to try this stuff out... so you DO get familiar with it. Nothing breaks... nothing bizarre... You should understand what the car does using the "emergency" brake procedure. I do now!

    Holding the button down so parking brake engages, does NOT cut motor power. If you're also holding the go pedal down it will fight the brake (in the rear). I bet the motor would win if you got serious on the go pedal and continued to hold the P button. I'm not sure how "D" cars would behave with front and rear motors when the brake is obviously only on the rear... which motor gets more torque split in this case.. dunno.

    On classic cars like mine (RWD only) you stay in the Orange range of the power band, if you hold pedal down and do a brake action. I said it "feels" like regen using the Park brake, but there's no regen about it. It is drag-only slowing.

    There is NO other message pop up saying "you have accelerator and brake at same time - release one them". Only the "using parking brake" message stays popped up as long as you hold the P button.

    I did this on a slippery snow/ice covered road. What the hell why not.. ? In doing maybe 50km/h there was no drama.. skidding sideways or anything like that just a controlled-down speed to stops. Kind of like ABS is working back there on the e-brake... something is making a tapping sound ... like modulated pressure, maybe?

    Here's another finding: if you release the P button after holding it and slowing down for awhile (but don't stop) the car direction stays in the direction you're still rolling after letting go of the button. That sentence had some redundancy in it. In other words, if you are in Drive (forward) and try some Park brake action, and then release the Park button before coming to a stop... you'll remain in Drive (and not go into Neutral and not go into Park).

    If you actually use enough brake to come to rest using the Park brake alone... the car DOES shift itself into Park, and door handles present.

    Here's the final tid-bit.... the BRAKE lights DO come on as soon as the button is pressed, and even before the brakes actually get applied. You can tap the button and send a flash back there to anyone without actually losing any forward momentum. You can see the lights on the mini-me car on the instrument cluster.

    OK... happy driving, and stopping in an emergency... if you need to. Or just want to have some fun.
     
    • Informative x 4
    • Helpful x 1
    • Like x 1
  13. LoL Rick

    LoL Rick Like Buttah

    Joined:
    Apr 21, 2014
    Messages:
    723
    Location:
    Land O Lakes, FL
    You can press the stalk down instead of up to shift into neutral. Then there is no danger of accidentally selecting reverse, no matter the speed.
     
  14. Geoff

    Geoff Member

    Joined:
    Dec 3, 2010
    Messages:
    70
    Location:
    Seattle, WA
    Thanks ScottM for the info! I have hit the Parking button by accident but hadn't played around with it. Good info to know!
     
  15. scottm

    scottm Active Member

    Joined:
    Jun 13, 2014
    Messages:
    1,932
    Location:
    Canada
    #15 scottm, Nov 21, 2016
    Last edited: Nov 21, 2016
    Careful here! There is something speed sensitive to be aware of:

    If you are moving forward in Drive at slow speeds (think parking lot crawls) and you whack the direction selector switch all the way to Reverse... the car *does* go into Reverse but you will still be rolling forward. When you press the go pedal, your direction of travel changes abruptly and you're now going backwards. And vise versa, slow Reverse to Drive and it will go into Drive your next power application will change you to a forward direction.

    Above a certain speed, this is no longer true. For example at highway speed, you can whack the selector all the other way from Drive to Reverse (in one go) and the car does not select that direction. It picks Neutral.

    People Know your Direction Selector!

    Pop quiz: without checking the car but just your memory... How may detent positions will you find on the "gear" selector, as you move it through its whole range? And where are the Drive and Reverse positions located, up or down.

    Pick one answer:

    2 positions - the car is in Drive or Reverse at all times. Stalk stays up for Drive (normal resting position), bumps down for Reverse.
    2 positions - the car is in Drive or Reverse at all times. Stalk stays down for Drive (normal resting position), bumps up for Reverse.
    3 positions - the switch is always resting in a middle position with one bump up for Drive and one bump down for Reverse. If you bump the opposite direction you're going, you get Neutral.
    3 positions - the switch is always resting in a middle position with one bump down for Drive and one bump up for Reverse. If you bump the opposite direction you're going, you get Neutral.
    5 positions - the switch rests in a middle position (Neutral) with one bump up or down also gives Neutral (from whatever gear you happen to be in) or two bumps up for Drive, or two bumps down for Reverse.
    5 positions - the switch rests in a middle position (Neutral) with one bump up or down also gives Neutral (from whatever gear you happen to be in) or two bumps down for Drive, or two bumps up for Reverse

    So you think you know your Tesla, huh? Now go check the car!

    Surprised!? o_O Or did you get it right? :cool:
     
  16. Moonwick

    Moonwick Member

    Joined:
    Dec 4, 2014
    Messages:
    72
    Location:
    Atlanta, GA
    I can confirm from my own experience that you can go directly from reverse into drive (and vice versa) all the way up to the breathtaking speed of 5 miles per hour. This is actually a source of annoyance for me as my Volt will let you slam between modes at any ol' speed, and it handles it quite gracefully; it will apply regen according to how hard the accelerator is applied until the car has stopped, and then the new mode takes over.

    I use this to great effect nearly every time I back into my driveway upon arriving home, probably much to the befuddlement of any nearby ICE drivers that happen to be paying attention. ;)
     
    • Like x 1
  17. scottm

    scottm Active Member

    Joined:
    Jun 13, 2014
    Messages:
    1,932
    Location:
    Canada
    #17 scottm, Nov 23, 2016
    Last edited: Nov 23, 2016
    I agree that Tesla could up the threshold speed a bit to allow for (car will accept) higher speed transitions from R-to-D and D-to-R... many times I'm just over the threshold and the car slips into Neutral so now I'm coasting either backward or forward and must press the brake pedal to get the car into any direction.

    Hitting the brake halts any "glide momentum" you were mentally counting on to complete your smooth maneuver. So sometimes, I have to select the direct I was just going in to "finish a bit more" THEN brake and switch again to the direction I had originally shifted into that went into N instead. Double embarrassing herky jerky pedal work and direction toggling ... as everyone in the car wonders what you're doing. "Amateur!" This is the EV equivalent to "blowing the shift"... and having to use clutch pedal again to get a gear, without grinding. Remember clutch pedals? whoa that's a throwback

    Of course, it usually happens when you want "quick transitions" and are trying to make "quick parking maneuvers"... and get that dreaded "N" indicator lit up on the cluster ...as you're repeatedly whacking the shifter trying to get the car into Drive or whatever... Sh*T !! Now you have to then do the pedal shuffle thing and hit the brake to get the direction you want to "take" ... and then continue on your way. Was that really necessary?

    In many cases, if only the threshold were just 5 km/h higher... most of this shuffle would become unnecessary. Just a little more pretty please Tesla.

    Cool that Volt has no upper limit! It makes sense ... it's only logical, if a bit unnatural, that the "go" pedal becomes the "regen pedal" if your selected direction of travel is opposite to the direction you happen to be going. (Mentally bizarre that pressing the go pedal is slowing your direction... until you get used to it.) PLUS this gives the driver an option for variable regen .. you can apply "more" if that stop sign is coming up quicker than you'd like and are predicting the car will not regen enough on its own with with just a pedal lift... and you know there's more regen room on the dial.

    The question becomes: what should the car show on the taillights when you hit "reverse" when you're at speed moving forward? Do the reverse lights come on when you're travel at 60 mph as soon as R is selected in Volt or do they only start to show when say, you've slowed to 5 mph and it's more obvious the car is now capable of changing direction and will be going backward if you keep this up? (please tell Volt experience!)

    I guess the better way to offer variable regen per stop cycle is to not overload the meaning of an existing control, like the "direction selection" ... and just give the user an explicit control that puts more regen effort into the car. It could be a paddle on the steering stalk that let's the driver dip into any unused regen with a variable amount of "regen now". Regardless of what's going on with pedals, it cuts power input the motor and flips into regen mode.
     
    • Like x 1

Share This Page