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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

#701

Post by kube-system »

usrusr wrote: post #285
pkolaczk wrote: post #271

Earlier quoted context omitted.

Another part of the point is that you can pack a much smaller and more efficient ICE and then substitute the missing power and torque from electric motors when needed. Most cars are not used at max power all the time. You need max power only at short times when accelerating. With pure ICE there is the tradeoff - a bigger engine will get you more max power / max torque but is going to be less fuel efficient because of…

On paper, yes, but did that ever happen? Sorry for being sarcastic, but where I live the frugal hybrid is exceptionally rare and the "same big engine, but driving a much heavier car" hybrid is omnipresent. The kind of people who might buy the frugal one buy second or third hand while almost all buyers of factory new pick the "same big engine" option, and those are the ones who decide what's available on the second ha…

The vast majority of hybrids use simulated atkinson cycle... while their cylinders might be the same size as N/A vehicles, they leave the intake valve open past the end of the stroke, so they effectively are displacing less, even though the cylinder dimensions might be the same size. The advantage is that atkinson cycle is more efficient. But it has too poor performance characteristics for an ICE-only car.

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

#702

Post by sokoloff »

usrusr wrote: post #465
xxs wrote: post #400

Earlier quoted context omitted.

>On paper, yes, but did that ever happen? Like absolutely, unless you consider 1.4L petrol engine large for something with over 170KW (over 220hp). Such kind of offerings are quite common at the East side of the pond.

I'd consider engines with HP in the two digits range not big. Few ICE cars (hybrid or not) are ever accelerated at the rate you could achieve with a 75 HP engine revved into the high but still safe range. People buy big engines so that they can get all their acceleration needs served at half throttle. And that's for stick shifting, those on automatic pick engine size so that they can accelerate on quarter throttle or…

Our family owned a Mercedes 240D (71 peak horsepower at sea level) for many years. That car's performance was lackluster on a good day and trying to merge onto the Pennsylvania Turnpike (with very short acceleration lanes) was IMO quite unsafe. From that experience, I'm pretty sure that people are dipping into more acceleration than that car could ever muster.

I have no doubt that some people behave as you describe, but I think some of that is driven from a rational position of not wanting to buy a car that is incapable of anything more than their normal daily driving. If you need to accelerate quickly to merge safely into traffic, bringing only 75 [or 71] peak horsepower to the table isn't a comfortable position to be in.

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

#703

Post by sokoloff »

chasd00 wrote: post #684
ohdeargodno wrote: post #476

Earlier quoted context omitted.

There was, and it was shit. The Cléon-Fonte, despite all my love for its BBBBRRRRRRRRRRVVVVVVVVVVV was becoming wildly insufficient for the already ever heavier cars simply due to electronics and safety measures, and it was already a 1.2L. The smallest ever put on a Clio was a .999L, and anyone driving a Twingo knows how it behaves the moment there's... a slight incline, or two people in the care. 1.5L is an incredib…

I feel like I remember a pickup being available that was a 6L v8. So one cylinder in that engine had almost the same volume as all the cylinders in a 1.5L engine combined. That's pretty crazy to me. edit: oh it was mine heh, my first car was a 1979 ford with a 460 ( 7.5L v8 ). It was a hand me down from my grandfather, he said if i could get it running i could have it.

A 6 liter 4-cylinder would have the same volume in a single cylinder as a 1.5L engine. A V8 of that size would have half the volume in a single cylinder, not almost the same volume.

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

#704

Post by avalys »

slt2021 wrote: post #593
NewJazz wrote: post #578

Earlier quoted context omitted.

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

No one is debating that deceleration results in tire wear.

The two claims you've made are that deceleration results in more tire wear than acceleration, and that regenerative deceleration results in more tire wear than non-regenerative deceleration. These are what people are questioning you about.

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

#706

Post by xyzzyz »

mattlondon wrote: post #642
Aachen wrote: post #374

Earlier quoted context omitted.

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 g…

Only a tiny fraction of EV chargers are 100+ kW. Most are 10-20 kW. These are great for office parking garages or shopping malls, but stopping at one for 15 minutes gets you nowhere.

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

#707

Post by kube-system »

pmg101 wrote: post #349
mort96 wrote: post #278

Earlier quoted context omitted.

And, you can make much lighter and lower range electric cars without all those heavy batteries, and boost the range with diesel when needed. Very attractive in principle. Most cars are not using their full range all the time, for a lot of people a 50 mile range car would be more than enough 98% of the time, but that remaining 2% means that people end up buying 200 mile range cars instead. But then, do you end up remo…

I thought about PHEV but in the end went full EV simply because it seemed to me with two whole power trains that's 2x the components to go wrong/need maintenance.

That's a common misconception, but hybrids are almost never as complicated as an ICE powertrain plus an EV powertrain. E.g. most hybrids are able to eliminate many parts that ICE vehicles require, like, starters, drive belts, multi-ratio transmissions, alternators, etc. Because of this, many hybrids surpass ICE-only vehicles in reliability.

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

#708

Post by roelschroeven »

taeric wrote: post #542
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…

This is less a hybrid thing and more a new transmission thing. It, of course, isn't free. The efficiency of a CVT is a good 10-20 percent lower than previous transmissions. That said, currently, the win from keeping the engine at either the max power or the max efficiency speed is substantial. There are some really good videos out there going over how newer CVTs work. Looks like some people are working on ones that a…

The post you commented on was talking about Toyota hybrids though, who don't use a CVT in the sense you're talking about.

They use a series-parallel hybrid transmission which is sometimes called eCVT, but works completely different from a classic CVT. There are no pullies, belts, chains, none of that. What they do have is a couple of motor-generators and a differential to link the system up with the engine and the drive shaft. No friction losses like CTVs have.

See https://prius.ecrostech.com/original/PriusFrames.htm, or look up "Hybrid Synergy Drive" on Wikipedia or Youtube or your favorite search engine.

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

#709

Post by jhallenworld »

usrusr wrote: post #285
pkolaczk wrote: post #271

Earlier quoted context omitted.

Another part of the point is that you can pack a much smaller and more efficient ICE and then substitute the missing power and torque from electric motors when needed. Most cars are not used at max power all the time. You need max power only at short times when accelerating. With pure ICE there is the tradeoff - a bigger engine will get you more max power / max torque but is going to be less fuel efficient because of…

On paper, yes, but did that ever happen? Sorry for being sarcastic, but where I live the frugal hybrid is exceptionally rare and the "same big engine, but driving a much heavier car" hybrid is omnipresent. The kind of people who might buy the frugal one buy second or third hand while almost all buyers of factory new pick the "same big engine" option, and those are the ones who decide what's available on the second ha…

Yes, check out BYD's hybrids. The petrol engine is 46% efficient, which is pretty damn amazing. This is more efficient than most power plants (combined cycle plants are better- but most power plants are not combined-cycle).

So what is the well to wheel efficiency of this vs. pure electric? There are fuel transportation losses in one, and transmission line losses in the other. In many cities electricity is quite a bit more expensive than gas so hybrids are a better deal financially.

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

#710

Post by slt2021 »

avalys wrote: post #704
slt2021 wrote: post #593

Earlier quoted context omitted.

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

No one is debating that deceleration results in tire wear. The two claims you've made are that deceleration results in more tire wear than acceleration, and that regenerative deceleration results in more tire wear than non-regenerative deceleration. These are what people are questioning you about.

acceleration is irrelevant because you need to accelerate to move regardless.

what is relevant to prolong the tire lifetime is reducing the unnecessary tire friction against the road.

There is constant component that depends on the weight * velocity * mileage - you gonna encounter it in all scenarios

There is also a variable component that is driven by 1st derivative of speed (rate of acceleration/deceleration).

The high regeneration allows you faster acceleration/deceleration, but medium/lower will (1) change your driving behavior so that you accelerate more smoothly, and (2) change your deceleration so that you coast more and decelerate less

remember, car's kinetic energy is not a perfect energy storage, so that you could freely move energy from battery into car speed, and regenerate it back into battery.

apart from air resistance, there is 60% loss on the way back + tire wear penalty depending on accel/decel curve (1st speed derivative)

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