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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

#711

Post by roelschroeven »

dubbel wrote: post #311
mschild wrote: post #298

Earlier quoted context omitted.

> They should add some “brake cleaning” mode Also known as breaking. You could just do that once in a while.

If you don't break hard enough, it might still be the recuperation doing its work. Car producers can and do resolve this, e.g. iirc Audis don't use recuperation for the first breaking of the day. That way you don't have to remember to use the no-recuperation/break cleaning mode or break unnecessarily hard every now and then.

The manual recommends putting the car in neutral and then braking every once in a while to keep the brakes in good working order. Putting the car in neutral disables the recuperation and makes sure you really use the friction brakes.

(When I say "the manual", I mean both the manual of my previous car which was a hybrid Toyota Auris, and my current car which is a fully electric Volvo XC40.)

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

#712

Post by tkj922 »

potato3732842 wrote: post #454
MindSpunk wrote: post #350

Earlier quoted context omitted.

I've got both at the moment on my two Hondas. Both manual, one with a throttle cable and one with throttle-by-wire. There's quite a bit of difference in how they handle off throttle. The cable will just slam the throttle shut if you just jump off the pedal (obviously) and it jerks pretty hard. The throttle-by-wire car hangs the throttle a little when letting off and doesn't just immediately start decelerating. Then i…

The ECU is doing that because rapid changes in state are bad for emissions. Letting you just slam the throttle closed could result in a tiny, but measurable at OEM scale, amount of extra fuel going half burnt out the tailpipe. Slamming it open can cause too lean combustion and oxide byproducts which. The OEMs try real hard to prevent this because the amounts of emissions byproducts that aren't water or C02 they're al…

An idling I4 has about 10 injection cycles per second. And the ECU clocks injection time corrections at least at that rate, more likely at double that rate or more. So I think that the smoothing is mostly there for the owner's wellbeing, not emissions.

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

#713

Post by teamonkey »

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.

In some ways it’s more complicated. The battery management and cooling is a point of failure. It’s also heavier and so wear and tear on suspension is greater.

On the other hand, a Toyota hybrid doesn’t have a gearbox at all, not even a CVT. Instead it has something similar to a differential, it’s mechanically simple and very reliable. It uses the electric motor in place of a turbo, so that’s another common failure point removed. It doesn’t have a starter motor, and the Atkinson cycle engine should suffer less stress than an equivalent petrol.

Practically the biggest problem is finding a 3rd party garage who will inspect the hybrid parts as part of a service.

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

#714

Post by kube-system »

bryanlarsen wrote: post #514
m_fayer wrote: post #418

Earlier quoted context omitted.

That same insight applies to regular hybrids, and yet Toyota’s hybrids are legendary for their durability. There’s a reason half the cabs where I live are Prius station wagons, and it’s not their efficiency, judging by how they’re driven.

Consumer reports found that HEV's were the most reliable, and PHEV"s the least reliable. That's nonsensical, there's little difference between the two. Toyota is the biggest seller of HEV's, Stellantis of PHEV. That's the difference. EV's on paper should be the most reliable, but Tesla is the biggest seller of those. If you want reliability, choose by brand rather than engine type.

>Consumer reports found that HEV's were the most reliable, and PHEV"s the least reliable. That's nonsensical, there's little difference between the two.

Eh, it's not so much nonsensical, as it is that you're just misinterpreting the data.

This conversation here is specifically about powertrain reliability, but that isn't what consumer reports measures. They measure complaints about any feature on the vehicle, including ancillary accessories unrelated to the vehicle's ability to transport people.

But also as you point out, shitty engineering (Stellantis's specialty) is a bigger issue than any particular drivetrain type.

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

#715

Post by fragmede »

supportengineer wrote: post #679
thmsths wrote: post #571

Earlier quoted context omitted.

I've ridden in one and this was basically a case of "you get the worst of both worlds". The engine was small and running at a constant RPM, leading to an annoying noise in the cabin. The range extension was not particularly huge. Worse, when we did eventually run out of battery on one trip, the range extender was unable to recharge the battery after refueling the car, forcing us to scramble to find an available charg…

>> the range extender was unable to recharge the battery Could you expand on this? What was the actual problem? For example, did the range extender start and run? Did it put any energy into the battery at all?

The original BMW i3 had/has a lockout that prevented the range extender from charging the battery until it reached 6% in order to meet California's ZEV BEVx regulation.

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

#716

Post by klaff »

taeric wrote: post #665
klaff wrote: post #652

Earlier quoted context omitted.

If overall efficiency is what you see reflected in the EPA mileage numbers (or similar European tests), in what scenario would a lower efficiency transmission (lower Pout/Pin over some range of operating points?) lead to or even allow better overall efficiency?

I'm not sure I understand the question? You get the engine to hit its sweet spot and to hold it there. That gain outweighs the loss from the new transmission. This would be similar to hitting the optimal torque point. The idea there would be that you can get out of the acceleration phase faster, so that you can transition to a more efficient gear to maintain the speed for longer. The wikipedia looks to cover this wel…

Ah, thank you, I see the argument. I'm still a bit skeptical though when many non-CVT automatics are 6 or 8-speed models that there would be much "sweet spot" benefit left by being able to make relatively small changes in engine speed. Like many things probably depends on exactly what comparison is being made.

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

#717

Post by Dylan16807 »

CraigJPerry wrote: post #427
Dylan16807 wrote: post #229

Earlier quoted context omitted.

I'm not sure what you're arguing here. Bigger battery is more capacity sure. But their point was that even without a big battery they have enough capacity to get close to maximum effectiveness, contrary to ajross saying that a hybrid's capacity is "not really" effective and "at best" helps "some".

just mistaken about maximum effectiveness braking system = circa 1G of deceleration possible (depending on tyres, coeff of friction, temperature, ... etc etc) So max effectiveness is unreachable for any regen system on a consumer car hybrid or ev, by a factor of around 6x i believe? With recognition of the mistaken framing (near max effectiveness) we're back to the larger ev pack has a greater ability to sink current…

I think you might be using a very different definition of "effectiveness" than they are.

Their definition of effectiveness is the percentage of braking force that turns back into electricity and goes into the battery. If your regen system can only do .15G, but 90% of your braking is under .15G, then you'll have about 94% effectiveness by that definition. 94% is not max but it's near max.

It's not about what happens during peak braking, it's about what happens over entire drives.

And when they say "half or so of how fast I could stop" they're underestimating, that's a comparison to a normal but aggressive stop, not pushing the pedal into the ground.

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

#719

Post by sliken »

cperciva wrote: post #176
nine_k wrote: post #41

I suppose the same should apply to hybrid cars, which outnumber pure EVs significantly [1]. The effect comes from converting the kinetic energy back to the battery charge via generation instead of wasting it via friction, which is the whole point of hybrids. [1]: https://www.consumeraffairs.com/automotive/how-many-electric...

which is the whole point of hybrids Part of the point, not the whole point. Regenerative breaking is absolutely a win; but there can also be a significant benefit from allowing the ICE to remain in the RPM "sweet spot" rather than moving around a larger range.

There do exist serial hybrids where the engine produces electricity while maintaining the ideal RPM, and then is connected to a battery+electric motors.

However in practice the vast majority of hybrids do not use this approach and have motors that vary RPM with road speed (depending of gearing of course).

The common case of maintaining ideal RPM is the CVT, which most folks dislike, so much so that some models have a switch to pick how many fake gears you have to break up the boring drone of a constant RPM engine.

BTW, the chevy bolt was advertised as a serial hybrid, right up to the day it shipped.

I believe the most common serial hybrid today is an EV with a range extender.

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

#720

Post by taeric »

roelschroeven wrote: post #708
taeric wrote: post #542

Earlier quoted context omitted.

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 dr…

Ah, totally fair in that this particular transmission is better than the belt driven CVT stuff. I had thought they were still a bit worse than other transmissions, but it looks like if they are, it is on the order of 1% or so.

Is fascinating to watch these things work.

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