Engine braking for traction - possible w/ EVs?

RatLabGuy

RatLabGuy

You look like a monkey and smell like one too
Joined
May 18, 2005
Location
Churchville, MD
More of a theory / howzit work question.

In a conventional car, particularly 2wd, sometimes you have occasions to need to slow down in a controlled manner. You can do this by manually downshifting (these days typically using the electronic manual shift buttons) a gear or two, forcing the engine tobe backdriven at a much higher RPM causes a lot of resistance to the wheels moving and slowing you down through what we often call engine braking.
This was really useful today coming through back roads covered in snow, going downhill into a turn for example - hitting brakes would only force a slide and loss of traction. Slamming up a gear slows yo udown quickly.

It got me thinking... is there n equivolent with electric motor driven vehicles? Or do you just lose this convenient option? I'm not really up on how mot are set up but even in cases with a transmission I don't see how you'd get that inherent resistance.
 
Chris_M said:
Isn't that just the regenerative braking?
Click to expand...
Do you not have to apply the brakes for that to go into effect?

And again - can you manually adjust how much drag it has? W/ ICE if you change gearing it increases the drag bc of forcing more RPMs
 
RatLabGuy said:
Do you not have to apply the brakes for that to go into effect?

And again - can you manually adjust how much drag it has? W/ ICE if you change gearing it increases the drag bc of forcing more RPMs
Click to expand...
Depends. Some have adjustable regen braking( from feels like coasting to feels like you dropped anchor), and some also have one pedal driving ( brake pedal is used for emergency braking mostly)
 
@Andy J. took me for a ride in his and the regen braking with 1 pedal driving was impressive and made me jealous.
 
orange150 said:
On the few teslas I’ve driven, if you have regen braking turned on you only drive with one pedal.
Once you get used to it it’s kinda nice. You only use the brake when you need to stop in a hurry.
Click to expand...
This. It also makes big mountain downhills a lot less stressful because you’re not worried about the heat build up and your brakes fading off.
 
braxton357 said:
Engine braking is far more likely to cause you to lose control than using your brakes will on a loose surface for the record.
Click to expand...
So I guess the hazards go on automatically when the first rain drop hits the windshield for Ohio Tesla drivers?
 
I imagine a lot of it is managing expectations and knowing how your vehicle drives. I jump freely between my 2 stroke and 4 stroke dirtbikes, and electric SXS, and they all have their own characteristics to manage. I was shocked by how much engine braking (motor braking?) Tesla's have. On my SXS, there are 3 modes to control how much regen braking you get, and I constantly switch between them when going downhill to match the desired result. I think Tesla's have something similar, but I'm not sure how easy it is to manipulate. When I'm driving my big truck, I often turn the engine brake off in the rain because it can sometimes be too aggressive and cause the rearend to lockup if there's not a load on the back.
 
braxton357 said:
Downshift on an icy road and see where you end up. Then consider that every vehicle sold in the last 30 years has ABS.
Click to expand...
Not true. TJ/LJ with 44 don't have abs 🤣.

I'd be curious how an ev in one pedal drive acts when on snow/ice. You panic and lift your foot off the throttle and it locks up?
 
braxton357 said:
Downshift on an icy road and see where you end up. Then consider that every vehicle sold in the last 30 years has ABS.
Click to expand...
Stab the brakes on an icy road and see where you end up.

Cautious and prudent driving using both the brakes and the engine braking are ideal but in real icy conditions, there is nothing you can do, short of having studded tires.

Only vehicles made after 2012 had to have ABS IIRC.
 
RatLabGuy said:
More of a theory / howzit work question.

In a conventional car, particularly 2wd, sometimes you have occasions to need to slow down in a controlled manner. You can do this by manually downshifting (these days typically using the electronic manual shift buttons) a gear or two, forcing the engine tobe backdriven at a much higher RPM causes a lot of resistance to the wheels moving and slowing you down through what we often call engine braking.
This was really useful today coming through back roads covered in snow, going downhill into a turn for example - hitting brakes would only force a slide and loss of traction. Slamming up a gear slows yo udown quickly.

It got me thinking... is there n equivolent with electric motor driven vehicles? Or do you just lose this convenient option? I'm not really up on how mot are set up but even in cases with a transmission I don't see how you'd get that inherent resistance.
Click to expand...
It's better in an EV. You have an active regeneration system that takes your motion and uses it to recharge the battery. It acts like a low level braking. You begin to decelerate as soon as you let off the accelerator. In the Tesla, you almost never apply the brakes unless the car in front of you rapidly brakes.
 
braxton357 said:
Everyone I know that owns a Tesla is a shit driver, I imagine they probably cluelessly drive along like it's a regular day.
Click to expand...
Kinda like BMW drivers. One thing I used to love seeing is all the dickhead BMW drivers on the side with the hazards or in a ditch when a big snow storm rolled through in Belgium.

For the record, a Tesla can be an amazing car to drive. 0-60 is nice. But 45-100 is amazing for passing idiots doing 50 on Plank Rd. :)
 
braxton357 said:
Downshift on an icy road and see where you end up. Then consider that every vehicle sold in the last 30 years has ABS.
Click to expand...
Yesterday I was driving home on icy roads in our 2wd Mini.
There were several times I needed to slow down quickly to prepare for an upcoming downhill turn. A couple times I used the brakes and slid, but every time I downshifted I did not. I'm not talking about a hard slam to stop the car, I mean enough that engine compression slows down faster than feathering brakes while keeping steering in place.
Thats what got me thinking about this.

ABS works, but the reason its implimented is bc people already hit the brakes to stop and it makes a bad situation less bad.

Sidebar - this car also has some kind of "feature" that prevents wheel spin by refusing to allow the RPMs to go up when it detects slippage. While I guess it does help get you going in some circumstances its infuriating when you know you just need to gun it, deal with the slip and keep or get going.
 
RatLabGuy said:
Yesterday I was driving home on icy roads in our 2wd Mini.
There were several times I needed to slow down quickly to prepare for an upcoming downhill turn. A couple times I used the brakes and slid, but every time I downshifted I did not. I'm not talking about a hard slam to stop the car, I mean enough that engine compression slows down faster than feathering brakes while keeping steering in place.
Thats what got me thinking about this.

ABS works, but the reason its implimented is bc people already hit the brakes to stop and it makes a bad situation less bad.

Sidebar - this car also has some kind of "feature" that prevents wheel spin by refusing to allow the RPMs to go up when it detects slippage. While I guess it does help get you going in some circumstances its infuriating when you know you just need to gun it, deal with the slip and keep or get going.
Click to expand...
But the gov mandated safety devices are there to save you from yourself. You shouldn’t have to spin your tires because, safety.
 
Back
Top