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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

#251

Post by doikor »

teleforce wrote: post #141
stephen_g wrote: post #5

Good to have more data points and evidence, but this seems extremely well established by now? Zero tailpipe emissions, drastically removed brake dust, slightly higher tire wear (due to weight), but much better overall than ICE.

>drastically removed brake dust It will be very interesting to see the data for the same car that has many powertrain versions for example the Lexus UX with the UX 200 (ICE), UX 300h (hybrid) and UX 300e (EV) to test which one the best and the worst in term of brake dust residue. My hypotheses is that for brake dust residue the best is hybrid, 2nd will be ICE and the 3rd will be EV. This is due to the fact that the E…

EVs don’t really use the brakes during normal driving being mainly used for emergency braking.

You could achieve the same with engine braking with ICE but most don’t bother.

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

#252

Post by SV_BubbleTime »

BHSPitMonkey wrote: post #100
SV_BubbleTime wrote: post #79

Earlier quoted context omitted.

Wow. Well, I like that the people that think like this also probably live I places where you are actually driving a coal powered car. Like the clowns in Hawaii that have extra subsidies for EVs… their power comes directly from burning crude oil. I’m an automotive EE, and and the truth about EVs is in a rush to push them out the door, the media and politicians have set the tech back at least a decade by pretending it…

There are more benefits to EV conversion in a community than the use of renewable energy, noise and roadside air quality being pretty big ones. Also... how do you know there aren't Hawaiians charging their EVs using rooftop solar? I hear they're known for being in the sun sometimes.

> Also... how do you know there aren't Hawaiians charging their EVs using rooftop solar?

Because of math.

A 6 kW house, to charge a 60 kW battery… so long as everyone with an electric vehicle is charging them at their house for 10 sunny hours to charge from empty, you’re right and I’m wrong.

Some people could get by, but it leaves the solar for nothing else. If you leave the house while the sun is up you better get back because you’re losing daylight!

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

#253

Post by agurk »

MindSpunk wrote: post #186
cloverich wrote: post #153

Earlier quoted context omitted.

Surprisingly you can get nearly same effect in automatics. I put around 60k miles on my first automatic (after120k+ on my first two cars, manual transmissions) and when i got my brakes checked at 63k they noted my brakes were still "brand new". I do gamify reading traffic to try and brake as little as possible (to help pass time etc), but was still surprised how far this takes you given i do plenty of stop and go tra…

It's not "nearly". It's exactly the same effect. Compression braking. Even if you're not on the throttle the engine is still rotating as it's connected to the wheels. If the engine is rotating it is compressing air. If it's compressing air but not igniting fuel (throttle closed) then it will suck energy out of the wheels to compress the air. You can do it in an automatic, you just have to force it to select a lower g…

If it takes energy to compress the air in the cylinder - doesn't it also release most of that energy when that compressed air is expanded on the subsequent stroke?

If you release the compressed air without pushing the cylinder down you would lose that energy, but you would need a extra device to do so (by lifting a valve at the right time). This option does exist for large vehicles like trucks as a compression release engine brake [0], but this isn't something you'd have on a family car.

In a petrol engine you always want the same ratio of petrol to air in the mix that is taken into a cylinder. As you want to vary the amount of fuel, and therefore power developed, you have to be able to therefore limit the amount of air that is sucked in. Otherwise the engine would always run at full power.

There is a mechanical restrictor called a throttle plate that lives inside the throttle body that restricts how much air the cylinder can pull in (and therefore how much fuel is injected to get the same fuel/air mix). This is controlled by the throttle. When you are coasting, this plate is in its most closed position. This creates significant resistance on the intake stroke, and is where the majority of energy is lost during engine braking. This is also known as a pumping loss.

Diesels always intake the same amount of air, so they can compress it enough to autoignite the fuel. They vary the amount of fuel injected to the same volume of air. This means no throttle body or plate, so unless an extra exhaust restrictor has been added there is minimal engine braking on a diesel engine.

[0] https://en.wikipedia.org/wiki/Compression_release_engine_bra...

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

#254

Post by jve »

MindSpunk wrote: post #186
cloverich wrote: post #153

Earlier quoted context omitted.

Surprisingly you can get nearly same effect in automatics. I put around 60k miles on my first automatic (after120k+ on my first two cars, manual transmissions) and when i got my brakes checked at 63k they noted my brakes were still "brand new". I do gamify reading traffic to try and brake as little as possible (to help pass time etc), but was still surprised how far this takes you given i do plenty of stop and go tra…

It's not "nearly". It's exactly the same effect. Compression braking. Even if you're not on the throttle the engine is still rotating as it's connected to the wheels. If the engine is rotating it is compressing air. If it's compressing air but not igniting fuel (throttle closed) then it will suck energy out of the wheels to compress the air. You can do it in an automatic, you just have to force it to select a lower g…

I'v bee downshifting manually with automatic especially when riding downhill. The effect with Chrysler T&C 2009 was very noticable and effective.

Toyota Sienna 2015 - the braking effect is unfortunately minor.

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

#255

Post by [deleted] »

SV_BubbleTime wrote: post #252
BHSPitMonkey wrote: post #100

Earlier quoted context omitted.

There are more benefits to EV conversion in a community than the use of renewable energy, noise and roadside air quality being pretty big ones. Also... how do you know there aren't Hawaiians charging their EVs using rooftop solar? I hear they're known for being in the sun sometimes.

> Also... how do you know there aren't Hawaiians charging their EVs using rooftop solar? Because of math. A 6 kW house, to charge a 60 kW battery… so long as everyone with an electric vehicle is charging them at their house for 10 sunny hours to charge from empty, you’re right and I’m wrong. Some people could get by, but it leaves the solar for nothing else. If you leave the house while the sun is up you better get b…

[deleted]

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

#256

Post by wazoox »

dotancohen wrote: post #202
masklinn wrote: post #195

Earlier quoted context omitted.

No reason for it not to work, even more so if you think to downshift. It’s more common with manual as downshifting is a lot more natural but not fundamentally different. It’s just trivially easy with electric thanks to regen braking. Though with modern cars getting heavier if you have a small ICE these days you have almost no engine brake which makes some cases more difficult (unless it’s a mild hybrid with an electr…

I don't know about today's engines, but some early fuel injected engines would actually use more fuel when engine braking. In those early designs spark could not be cut off, so if this extra fuel were not added then the mixture would run very hot and risk pre-ignition and damage. I don't know about carbureted vehicles.

It only applies to mechanical injection and carburettor engines. With electronic injection, which is the norm since the 80s, this is not a problem.

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

#257

Post by angulardragon03 »

PeterStuer wrote: post #230

On my non EV car I seldom use the break unless in an emergency or I have to come to a full stop. I always use the cruise control to decelerate and accelerate. Anyone else has that habit?

… how do you think the cruise control decelerates you? Is this a troll post?

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

#258

Post by wazoox »

dotancohen wrote: post #203
MindSpunk wrote: post #154

Earlier quoted context omitted.

You don't engine brake with the clutch, you engine brake by downshifting and using the higher engine RPM in lower gears to brake the car via wasted compression.

And that downshifting involves a clutch operation, moving the engine into a higher RPM. That most certainly wears down the clutch, talking as someone who's replaced quite a few of them.

My 300k km Volvo S60 still runs on its original clutch, and I changed the brake pads only once. Engine braking is the way.

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

#259

Post by sub7 »

Has anyone modeled how much excess cement and asphalt pollution is generated by having a tiny car weigh as much as a giant truck? Or the water usage of increased lithium mining?

EVs are like an inferior product being shoved down everyone's throat when consumer cars don't even account for the most emissions globally.

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

#260

Post by esperent »

nottorp wrote: post #238
jjayj wrote: post #33

Earlier quoted context omitted.

I would love to have gone electric (bought a car in September) but I rent and don't have any way to charge at my residence. How do we solve the renters-that-cant-charge-their-cars problem?

Why renters? I own but I still wouldn't have any place to charge if i owned an EV...

If you own a house, generally you can do things like install charging points (also backup batteries, solar panels, better insulation, all kinds of fun things) that renters can't.

I'm sure there are some homeowners who can't - maybe listed buildings, or these weird HOA rules I hear about from Americans.

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