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A question about torque sleep

Discussion in 'Tesla' started by KarenRei, Aug 1, 2017.

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  1. KarenRei

    KarenRei KarenRei KarenRei KarenRei KarenRei KarenRei

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    #1 KarenRei, Aug 1, 2017
    Last edited: Aug 1, 2017
    I remember reading about torque sleep when it first was introduced - that it was active when in range mode, but range mode also limited heating / cooling. Is it possible to enable / disable without effects on climate control?

    Also, I was wondering about its effect on traction on slippery surfaces. Not on acceleration / braking (I know the torque comes back immediately for that), but icy, wet, or gravelly roads, where you may be trying to hold a constant speed in a straight line but the vehicle starts to slip / spin. That's my main reason for wanting AWD in my Model 3, so that there's four tires all providing torque when the road gets slippery. Does ESC / traction control detection of slip automatically "wake" the sleeping motor? Is it safest to disable torque sleep on such surfaces?

    Thanks :)
     
  2. BerTX

    BerTX Active Member

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    Range mode is only to be used when absolutely necessary. It does modify how climate control works, but it also changes heating and cooling of the battery away from the optimum for battery longevity. It should not be used on a regular basis.

    I don't know about how traction control affects torque sleep.
     
  3. chillaban

    chillaban Active Member

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    Torque sleep happens seamlessly both with and without range mode, and the time it takes for a motor to come out of sleep is absolutely negligible for snow/ice handling. Heck, it's still going to be faster than the time it takes for 99% of dynamic AWD mechanical systems to transfer any torque.
     
  4. KarenRei

    KarenRei KarenRei KarenRei KarenRei KarenRei KarenRei

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    So it can't be disabled? It's always active?

    It wasn't a question about time. It was a question about whether it happens at all if you're not accelerating or braking.

    I'm not sure whether you understood what's being talked about (I see you're from the Bay Area, so I'll understand if you don't have much winter driving experience). You made it sound as though someone responds to a slip by slamming on the brakes or the accelerator. The goal is first to not slip in the first place by having torque constantly applied to all four wheels. If you do slip it's detected by a series of sensors, including wheel speed, accelerometers, steering wheel position, etc. It applies gentle differential braking to different wheels to counter the direction of skid and gently cuts overall engine power. "Gently" is key, because if you do anything too significant once you start to skid you make the skid much worse.

    In short,

    1) If it's slippery, I'd probably want to disable torque sleep altogether, so that there's always even torque on all wheels to help prevent skid in the first place. Is this possible?

    2) If it was on, I'd want it to not simply wake up the sleeping engine on accel/decel, but also on ESC. Does it?
     
  5. chillaban

    chillaban Active Member

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    Sigh, I live in the bay area now, but I grew up in Michigan, went to school in Boston, and have driven through a lot of snow and ice in my time. It's probably not iceland, but I understand how snow handling works. I was referring to systems like Audi Quattro, torsen central diffs, and similar systems. All default to a misbalanced torque application (e.g. 40/60, 20/80) which then responds mechanically to small amounts of wheelslip by rebalancing torque. Tesla torque sleep is supposed to wake up in 1-2 milliseconds, and engagement/disengagement does not require in torque pulses to the wheel, which is common in a lot of lower-end partial engagement AWD systems.

    There's many ways that TCS/ESP systems respond to severe loss of traction as seen in wheelslips, but the time that it takes to acquate brakes or cut engine power, torque sleep could've woken up or went to sleep millions of times. It takes single digit milliseconds to switch from idle to active in an electric motor. Perhaps you're more expecting torque sleep to be like a part-time-engaged mechanical center diff or a neutral-coasting transmission?
     
  6. KarenRei

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    Haha, okay, Michigan qualifies as sufficiently familiar with winter driving ;)

    Again, I'm not raising an issue of how long it takes to wake; I'm well aware of its response speed. My question is does it wake on ESC? And can you disable it so that you always have torque on all four wheels to help prevent slip in the first place?

    To reiterate, from my previous posts.

    "Does ESC / traction control detection of slip automatically "wake" the sleeping motor? Is it safest to disable torque sleep on such surfaces?"

    "It wasn't a question about time. It was a question about whether it happens at all if you're not accelerating or braking."

    "2) If it was on, I'd want it to not simply wake up the sleeping engine on accel/decel, but also on ESC. Does it?"

    At no point have I had any doubts about the speed at which the motor is woken up, so you don't need to keep mentioning that :) It's a question of whether they are woken up on ESC at all. And - as noted - whether it's possible to shut it off altogether regardless.
     
  7. DrivingRockies

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    Do you have info to back that up? I was told by the service center it absolutely does NOT have an affect on the battery temperatures.
     
  8. BerTX

    BerTX Active Member

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    Nope, I can go back and find discussions on it from the past, but it is possible they have changed how it works, so it would be pointless.

    Always believe what Service Center and other Tesla employees tell you. That is your most authoritative source. (sarcasm, in case there is any doubt).

    I would love to be wrong about this, so I'd love to know the correct answer. It is a part of Tesla lore (meaning the info is more than two years old) and could be wrong.
     
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  9. DrivingRockies

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    Yea. I find they're right about 50% of the time. About as accurate as me just guessing...
     
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  10. KarenRei

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    Looks like nobody here knows whether ESC wakes torque sleep, and whether torque sleep can be disabled :(
     
  11. sandpiper

    sandpiper Active Member

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    I wonder about that. On my car, there is a perceptible increase in the slight high pitched whine that comes from the front motor, when range mode is engaged.
     

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