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Regen and Friction Brakes to Full Stop

36

Description

When releasing the accelerator, slowly come to a complete stop (but faster than the current design).

Competitive/Pricing/Notes

Currently regen stops at about 5 mph.  At that point this feature would lightly engage the friction brakes to come to a complete stop (if Creep feature off).

Several other cars like the Leaf and Bolt use use a PM motor. Due to inefficiency of the PM motor, a side benefit is it will slow to a stop on level ground.

Status

Unknown.

(edited by moderator)



Category: Tags: entered 30-Apr-2018

6 Comments

My wife just bought a 2018 LEAF with this regen/friction feature. Nice.
I find too much regen uncomfortable.  Just my two cents.
This proposed change would only apply to people who do not use the creep function setting.  It would be interesting if Tesla would tell us the approximate percentage of how many owners use the creep function.  I suspect creep's use is higher than some would guess.
Not a regen fan as it is an abrupt action.  Like my ride smooth.  The lowest regen setting and Chill mode is just right for me and my passengers.
Preface: once you get used to one-pedal driving, you can make it real smooth even with the default strong regen braking. Trick is to change that habit of completely backing off the accelerator when slowing down, instead to slowly back off the accelerator.

So if you get used to this and also not having “creep mode”, it makes perfect sense to have the car come to a complete stop with accelerator off. I would make the option conditional on turning off creep mode, and perhaps also conditional on using strong/standard regen.

I suppose the issue is, what happens when regen braking has been automatically disabled, because of 100% charge, temperature, or some other variable?
Its straightforward to brake in a consistent manner despite differing levels of battery SOC preventing a fixed approach. One takes the input vector of standardized G force per unit of speed modified by percentage of pedal travel and tests that against the actual G force experienced. The difference is the amount the motor regen process is not tolerating all the way to a theoretical 100% (no regen capability). The friction brake is proportionately applied based on this difference. As the car slows, the calculation is done many times per second to stay in line with the hard coded maximum deceleration curve this feature supports. One comes to a complete stop regardless of regen capacity or steepness of incline the car is currently on. I don't know that this is how  Nissan has done it, but this is one approach to the problem. There are a number of video reviewers that have driven the Nissan with this feature, and the comments are the same - you get used to it and love it. There is no need to move the foot between the two pedals in what is always a less than smooth manner. Emergency stops are the exception, and of course it doesn't matter that it was jerky. It was an emergency.