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Comment by whycome | Hacker News Reader

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.

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I did this with manual, and my EV does this with a single pedal control. Letting off of the pedal will engage regenerative breaking to the extent that you let off the pedal, it does not engage the brakes. I find that in a lot of city driving I don't need the brakes, but they do work fine when I need them. I really like this functionality. The car can also creep along at 1-2 Mph when necessary - so I don't need brakes to deal with slow traffic. (With a manual, first gear would sometimes suffice for this.)

So the premise in the title of the article does not surprise me, but I thought that the primary pollution complaint about electric vehicles was tire pollution and not brake dust.

Some EVs have that. Anecdotally, once you get used to "one pedal driving" having that sort of control (via extra input mechanisms like steering wheel pedals) is just plain annoying.

My Bolt has a hand paddle behind the steering wheel that engages regenerative brakes (and only the regenerative brakes). I make use of it extensively. When in "single pedal" (where the accelerator acts as a speed selector, i.e., the car brakes when you step off the 'gas'), it's a lot more aggressive than just lifting my foot off the pedal, and when in "simulate an automatic transmission" 2 pedal mode, I find the paddle is easier than figuring out exactly where the threshold is on my brake pedal between regen and friction brakes.

I love my bolt, but I wish it allowed you to choose a less aggressive setting when using the steering wheel paddle. My old leaf had that option.

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

The bolt EUV has a paddle on the wheel above the turn signal stalk that is used to invoke regen braking in normal drive mode, and when used in one-pedal drive mode adds an extra bit of regen without having to use the brake pedal. It also doubles to cancel cruise control. It's in the perfect location too. And it feels very well blended, precise, constant, and smooth.

Every other EV should have this. I often get EV rental Hyundais, which have 4 levels of iPedal - 3 regen levels and "max" aka one-pedal drive. They're managed by paddle shifters on the wheel. They don't default back to one pedal and any extra re-gen is still managed by the brake pedal.

I googled to find a link to share in this comment to discover how much love (or superiority complex) the chevy regen paddle has -- https://www.chevybolt.org/threads/regen-paddle-the-superior-...

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 the limit of the batteries to accept power input.

Another way of further reducing brake dust might be to have a higher regen setting that dumps excess power to a heat sink and cooling system, up to its limit before engaging the mechanical brake pads/discs.

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...

>>the dynamics like that are abstracted away in EVs (i.e. dumbed down) or buried in menus and not readily accessible.

Exactly, they already do regen first, then mechanical braking, and just hide all the details.

I would like to see those details available so I can tune them (it'd be ok if they put safety limits on where they know the capabilities of the batteries, electronics, etc. far better than I ever could). Just a nice to have...

Pretty much all hybrids already do this, but automatically. When you press the brake pedal, they will command regen first, and only the hydraulic brakes under conditions when regen is not enough.

Series hybrids also have the ability to dump excess power just like you are suggesting as well. Instead of resistor banks (like trains) they often dump energy by using the generator to spin the engine… literally engine braking.

Some vehicles repurpose shift paddles as a way to trigger regen braking. But they're pretty gimmicky and not really useful for driving. If you want to use regen in a vehicle that supports it, the brake pedal does that. And when regen is not enough, the hydraulic brakes are also used. But a "sometimes brake" pedal that only support regen sounds like a bad idea. Vehicle controls as essential as braking need to be consistant in how they respond to input behavior.

I've been driving a Chevy Bolt for over 8 years now, and I regularly use the regen paddle. I drive in "L" mode, which engages partial regen when the accelerator is released. When I need more slowing, I pull the paddle, and that increases the aggressiveness of the regen. I only press the brake for quick stops, or to hold the car once it has stopped.

I also use the built in "hilltop reserve" feature, which limits charging to 90%. This ensures that there is always regen resistance, and therefore a consistent experience.

Was it that common? Where I’m from that’s “winter driving mode” because it’s safer on slippery surfaces, but rarely anyone would do that in the summer time.

My EV is set on max regen mode though, and I sometimes drive without pressing the brakes, as there’s a paddle I can use to use regen for all my braking needs bar an emergency. It even has a name - single pedal driving.

Can't speak to if it's common, but it was how I was taught and drove in California... so there was rarely any winter conditions to speak of.

I preferred downshifting VS braking, personally

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

Also fun! Half the fun of a manual for me is double-clutching (totally not necessary unless you have no synchros but it's a fun challenge) and nailing the rev-match on a downshift.

'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.

When I visited a nearby observatory it was fun driving on the mountain and seeing the signs telling you to use engine braking on the way down and trying it for the first time.

?! - I'm clearly missing something because I'm failing to understand how people don't know about engine braking or have just tried it for the first time, and actually have a licence. It's approximately lesson number four in typical driving tuition.

My car (an old Jetta) lasted ~20 years and was still good to go when I got rid of it. Only the body itself had any issues. I suppose the use would vary based on terrain? It was useful to get to a gear with more torque for taking off again. And I guess you’re not doing it from really high revs — so it was just using the engine to slow things

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