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Electric cars produce less brake dust pollution than combustion-engine cars

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Re: Electric cars produce less brake dust pollution than combustion-engine cars

#591

Post by janosch_123 »

D13Fd wrote: post #577
nordsieck wrote: post #567

From what I've heard there's a countervailing effect for EVs, though - they end up generating more particulate pollution from tire wear because of greater vehicle weight and greater torque. The number that I've seen bandied about is ~20% greater tire wear.

That was my first thought. Fewer brake particles is great, but I’m guessing it won’t be enough to counter the increased tire wear.

Not sure about that. If you accelerate a 2t vehicle to 60mph and then decelerate it back to 0mph then they would stress the tyres in the same way, no matter if you do EV & regen, EV no-regen or ICE, right? (I am keeping the weight constant).

Prompted by your comment I had a look at vehicle weights and two facts stood out

- ALL new cars are getting heavier EVERY YEAR because we keep adding more stuff (average car weight, and average SUV weight trend upwards from 2016 to 2023)

- The average electric car is heavier than a petrol equivalent but is lighter than an SUV

Weight certainly a problem, but the focus on EVs for weight is generally blown out of proportion.

https://www.thisismoney.co.uk/money/cars/article-13588773/Ne... https://www.sustainabilitybynumbers.com/p/weighty-issue-of-e...

Re: Electric cars produce less brake dust pollution than combustion-engine cars

#592

Post by nixass »

pinko wrote: post #516
nixass wrote: post #508

Earlier quoted context omitted.

That's the case only with CVT transmission

Are there still a lot of hybrids without CVTs?

I'd say that the market is very fragmented.

Toyota and Lexus, obviously, use eCVT in their cars.

Honda is also in eCVT camp for most of their models but for example new CR-V has weird setup. It acts as an BEV until ~80-100kmh and then shifts completely to ICE with a single gear. While in EV mode the engine is constantly charging batteries.

Then you have KIA and Hyundai with their dual clutch setup in all HEV and PHEV range.

Re: Electric cars produce less brake dust pollution than combustion-engine cars

#593

Post by slt2021 »

NewJazz wrote: post #578
slt2021 wrote: post #517

Earlier quoted context omitted.

when car decelerates, the kinetic energy has to go somewhere, large part of it goes to battery as regeneration (60%), the rest goes to tire/road friction and wear

That doesn't answer my question even a little bit.

From the physics perspective, where does kinetic energy go in E=1/2mv^2 ?

Up to 60% goes back to battery, part goes to air resistance and rolling tire resistance (can be ignored for our case as its the same regardless of regen setting), the rest goes to friction of tire/road due to slowing down tire speed

Re: Electric cars produce less brake dust pollution than combustion-engine cars

#594

Post by taeric »

RegnisGnaw wrote: post #554
taeric wrote: post #543

Earlier quoted context omitted.

I'm curious what you mean? I'm fairly confident the post you are responding to was only talking about newer transmissions. Which, I can't imagine those are going away?

The post is talking about most people drive with BEV , which is one pedal driving. My Tesla does one pedal driving my default. China has banned "one pedal driving" as a default.

I took it to be people that are far more aggressive with the gas pedal than they really need to be. That is, it was more the heavy foot than it was letting off to brake.

Regardless, your point stands. People that have gotten used to not directly using brakes to indicate you are slowing down is a dangerous thing with how reliant we are on the standard indications that you are slowing. All the more so if you need to rapidly lose a ton of speed, where even regenerative brakes often fall back to friction.

Re: Electric cars produce less brake dust pollution than combustion-engine cars

#595

Post by _jss »

SoftTalker wrote: post #589
tonymet wrote: post #580

You can get similar results with proper deceleration, engine braking and downshifting. I’ve had brake pads last 110k miles (with room for 20k+ more), even though I lived in moderate hilly area. That’s probably 1/3 the brake dust, and comparable to an EV . If you are getting lower MPG than the EPA rating, you are also burning up your brakes from heavy deceleration. Improve your MPG to 15% over EPA and your brakes will…

But in a manual transmission car, downshifting and engine braking produces clutch dust instead of brake dust (basically the same thing).

In a modern car, or if you adequately rev match, the clutch wear is extremely small. Only if you are aggressively down shifting will that be a problem. It’s also only wear at that point in time, not the entire time through engine braking.

Re: Electric cars produce less brake dust pollution than combustion-engine cars

#596

Post by kylebenzle »

SoftTalker wrote: post #589
tonymet wrote: post #580

You can get similar results with proper deceleration, engine braking and downshifting. I’ve had brake pads last 110k miles (with room for 20k+ more), even though I lived in moderate hilly area. That’s probably 1/3 the brake dust, and comparable to an EV . If you are getting lower MPG than the EPA rating, you are also burning up your brakes from heavy deceleration. Improve your MPG to 15% over EPA and your brakes will…

But in a manual transmission car, downshifting and engine braking produces clutch dust instead of brake dust (basically the same thing).

Well, that's just not true at all now is it?

Re: Electric cars produce less brake dust pollution than combustion-engine cars

#597

Post by pdabbadabba »

tonymet wrote: post #583
nordsieck wrote: post #567

From what I've heard there's a countervailing effect for EVs, though - they end up generating more particulate pollution from tire wear because of greater vehicle weight and greater torque. The number that I've seen bandied about is ~20% greater tire wear.

They address this briefly in the article (though inadequately) , that tire particles are heavier and doesn’t end up in the air like brake dust. But you do raise a good point at the holistic condition, and assessing a broader population with less than ideal configuration. They are looking at lightweight EVs at lower speeds. But Americans drive heavier EVs at highway speeds. The rotors & pads are huge.

> They are looking at lightweight EVs at lower speeds. But Americans drive heavier EVs at highway speeds. The rotors & pads are huge.

Perhaps other EV drivers can chime in but, if anything, I think I use my friction brakes less at highway speeds where, in general, you're not really supposed to do a lot of braking. I'd say, overall and regardless of speed, my friction brakes are really used only to bring the car to a complete stop or for emergency braking to avoid a potential accident.

Re: Electric cars produce less brake dust pollution than combustion-engine cars

#598

Post by bevr1337 »

SoftTalker wrote: post #589
tonymet wrote: post #580

You can get similar results with proper deceleration, engine braking and downshifting. I’ve had brake pads last 110k miles (with room for 20k+ more), even though I lived in moderate hilly area. That’s probably 1/3 the brake dust, and comparable to an EV . If you are getting lower MPG than the EPA rating, you are also burning up your brakes from heavy deceleration. Improve your MPG to 15% over EPA and your brakes will…

But in a manual transmission car, downshifting and engine braking produces clutch dust instead of brake dust (basically the same thing).

Anecdotally, every car I've been in where the driver talks about engine braking is rode hard and put up wet. Humans seem pretty bad at downshifting/engine braking outside of vehicles designed for that purpose like big rigs. Cars have much fewer gears so it's harder to align the downshift.

Of course there's little use in having this conversation since we all think ourselves above average drivers. I've had acquaintances reply "I don't even need a clutch I can shift so smooth!" (Do not attempt.)

Re: Electric cars produce less brake dust pollution than combustion-engine cars

#599

Post by jetbalsa »

whycome wrote: post #588
janosch_123 wrote: post #540

For DIY EV conversions (I built some cars) you usually hook up the "regenerate braking" to the brakelight switch. So as soon as you tap the brake pedal just a little, you start regenerating and see the amps flow back into the battery (I have a little display on my dashboard). Only when you press the pedal further, do you start engaging the friction brakes. I have no statistics on brake pad differences because we didn…

With a manual car, it was common to downshift and use the engine to decelerate. I’m wondering if electric vehicles might actually cause a return to a third pedal to re-add some of the fine tuned controls that a manual transmission allowed. Maybe the “downshift” could engage the regen brake specifically.

Some EVs have single pedal mode, where if you let off the gas it will bring you to a complete stop,

Re: Electric cars produce less brake dust pollution than combustion-engine cars

#600

Post by tonymet »

SoftTalker wrote: post #589
tonymet wrote: post #580

You can get similar results with proper deceleration, engine braking and downshifting. I’ve had brake pads last 110k miles (with room for 20k+ more), even though I lived in moderate hilly area. That’s probably 1/3 the brake dust, and comparable to an EV . If you are getting lower MPG than the EPA rating, you are also burning up your brakes from heavy deceleration. Improve your MPG to 15% over EPA and your brakes will…

But in a manual transmission car, downshifting and engine braking produces clutch dust instead of brake dust (basically the same thing).

not quite. Think of a 2 mile descent. The clutch is only engaged for a fraction of a second. rest of the 2 miles is engine braking.

When done properly , clutch wear is minimal. My clutch lasted > 150k miles and still going

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