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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

#641

Post by chiffre01 »

SV_BubbleTime wrote: post #79
rayiner wrote: post #16

We should obviously ban combustion engine cars, at least starting with cities. I can’t think of a single clearer win for air quality.

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…

Automotive EE engineer? I'm sure everyone here would love your explanation of EV efficiencies vs ICE in different situations.

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

#642

Post by mattlondon »

Aachen wrote: post #374
mattlondon wrote: post #329

Earlier quoted context omitted.

> Not as much as gas chargers In the UK at least, there are more EV chargers than gas/petrol stations: https://www.vertumotors.com/news/there-are-more-charging-poi...

Also after you divide the amount of time required? So if an average charging session is 100 minutes and getting petrol is 5 minutes, you'd need 20 times more chargers to break even on availability. And I'm not sure that even works the same when considering that these events are probably bursty (most people will arrive at an energy station at a similar time of day) In case it sounds like I'm gas station lobby: I'm not…

I don't think it even includes the ones at people's homes where probably "most" charging happens. No one has a gas station at home.

FWIW a fast charge is like 10-15 mins usually while you grab a coffee or something - in modern EV cars you have 100-200kw (or more!) charging where you can get like 400 or 500 miles in an hour, so 15mins gives you 100-125 miles extra range etc. If you time it, filling up a gas tank and going in to pay and all that is not like 40 seconds but more in the 5-10 mins mark, so 15 mins top up on a longer journey is not that much longer than filling up.

It's a bit of a different mentality really - with petrol/gas I'd fill up to the brim then drive until I was almost empty, but with an EV I wake up with a full tank and just do a quick top off here and there during the day (assuming I ever need it which 99% of the time I don't) until I can get home and charge overnight where is way way cheaper.

With petrol I'd never stop to just put in a few litres at a time, but doing it with an EV is so simple and easy, and you can go do something else while it's happening. Picking up some groceries, getting a coffee, bio break etc - perfect time for a top up

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

#643

Post by erikerikson »

prova_modena wrote: post #633
Eric_WVGG wrote: post #632

Earlier quoted context omitted.

I used to do that with a vintage 70's sportscar… later learned that it was pretty bad for the long-term life of the transmission so had to train myself out of it.

It's gentle on the transmission and clutch if you rev match on the downshifts.

Or see the hill coming and downshift before it is needed

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

#644

Post by mnw21cam »

Finnucane wrote: post #634
whycome wrote: post #588

Earlier quoted context omitted.

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.

'common'? When I was a young'n, I was taught that that was basically an emergency procedure to use if the brakes failed, to force the car to slow down. I can't imagine wanting to do that routinely.

If you drive down any significant hill, you either use engine braking, or you overheat your brakes. It's a fairly basic part of driving tuition and the driving test for a good reason.

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

#645

Post by cptskippy »

toss1 wrote: post #605
whycome wrote: post #588

Earlier quoted context omitted.

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.

Cool idea. Perhaps a better idea would be to borrow from the brake balance adjustment in race cars, wherein an adjuster dial/knob allows the driver to alter the balance between the front vs rear brakes when the brakes are applied (very useful in wet vs dry conditions, high-speed vs low-speed sections, etc.). So, instead of adjusting the F-R brake balance, the dial could adjust the regen-vs-mechanical braking, up to t…

Most of the dynamics like that are abstracted away in EVs (i.e. dumbed down) or buried in menus and not readily accessible. I think this is done in part because the majority of people don't know or care about them, and if they were readily accessible would toggle them unknowingly and be confused or upset. In the Nissan Leaf it was done intentionally to make the car feel as much like a traditional ICE as possible.

In the first gen Nissan Leaf you can toggle between two levels of regeneration by toggling "B mode" which mimics automatic transmission car's behavior in "Hill mode" or when disabling "Overdrive". In the Leaf it just increases regeneration strength when you let off the accelerator. Similarly you can adjust the acceleration curve by disengaging "Eco mode".

Turning Eco mode off and Hill mode on makes the Leaf a lot of fun to drive on winding mountain roads. Unfortunately you only get like 15 minutes of drive time...

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

#646

Post by coryrc »

vladvasiliu wrote: post #409
theshrike79 wrote: post #397

Earlier quoted context omitted.

This is the thing with good hybrids. The "gas pedal" becomes a "I want to go faster/slower" pedal, its position has zero impact on the RPM. As an anecdote: A security company I know only buys Toyota Hybrids for their guards just because of that. They have a habit of driving cars like they stole them and normal ICE cars break down from that kind of abuse. Hybrids won't let you abuse them, they pick the RPM and you dea…

Do all Toyotas do that? I'm pretty sure that my dad's Corolla will rev the engine when I press the gas if the engine is already running. I'm also surprised for the first few minutes when I drive it how little "engine braking" it has (my habit is from riding a big motorbike).

They're programmed to rev in situations like that, because people are used to it. Under normal operation, RPM is decided by power needs. If you start accelerating on the freeway, for example, the engine might jump from 1100 RPM to 3000 RPM with just some pedal, while a manual transmission obviously changes very little.

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

#647

Post by atoav »

I dream of a future where societes manage to price in all externalities into the objects they produce. This of course requires us to be(come) more honest about the hidden costs to society each and every objects and its usage brings with itself.

What we do with that knowledge is another question, but right now my feeling is a lot of bad actors skew the picture to make themselves look good while regular people are left to breath the dust.

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

#648

Post by coryrc »

p0w3n3d wrote: post #263
jnpnj wrote: post #227

Earlier quoted context omitted.

I heard about that long ago but couldn't find more, so IIUC chemically it's easier and more efficient to have a "one mode" combustion engine and let the electric engine deal with the variations, to the point that the reaction produces near no toxic byproducts, is that right ? I was wondering if there was research to keep improving that part. Even though it would help sustain the fossil fuel industry..

AFAIK this is about engine efficiency. ICEs have highest momentum and efficiency sweet spot somewhere in the middle of available revs, which depends on the engine construction and was being altered by different mechanisms (like turbocharging and variable valve timing) but since the electric engine (I'm speaking of Toyota solution) is able to keep the ICE in the sweet spot with its eCVT, the engine can be simplified a…

> ICEs have highest momentum and efficiency sweet spot somewhere in the middle of available revs

Close: they have the highest efficiency at about 90% of maximum torque for most of the RPM range. So if you want double the power, you want to be able to double the RPM; and if you want half the power, you want to be able to drop the RPMs in half. To pull this off, you either need a very quick shifting gearbox or some sort of CVT.

This is also why automatic transmissions, despite being ~80% efficient versus ~95% manual transmissions, are not much worse on mileage. Because they can quickly switch between low RPM and higher RPM (first by torque converter lockup, second by switching gears).

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

#649

Post by dotancohen » 

  > The health effect is especially critical for urban disadvantaged groups, where exposure to partical matter has been shown to be related to increased asthma rates, cardiovascular disease, and other respiratory conditions.
Why would the health effect be more critical for disadvantaged groups than for other urban groups?

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

#650

Post by stavros »

apelapan wrote: post #396
stavros wrote: post #370

Earlier quoted context omitted.

Hmm, I don't really understand what you mean. If I want to reduce speed far ahead, I just ease up on the throttle pedal a little, and the car slows down a little. If I ease up a lot, it slows down a lot. I'm not sure what you mean...

I want to glide at roughly constant speed for some distance. Some mild breaking is fine. I cant glide if I let off the accelerator, then I come to a fairly firm stop. I want my right foot on the break pedal, ready to brake hard and fast in the rare case that something comes across the road. I don't want to reduce speed any further than is necessary to have a safe breaking distance at fully ready state. With any other…

Ah OK, I see what you mean. Yeah, on my car, that's a setting I can toggle.
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