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Comment by sprior | Hacker News Reader

Correct me I'm wrong, but I was under the impression that EV's like Tesla don't really have a transmission as in gears to change, so as much as I'm a diehard manual transmission fan I figured that was where it ends. Now a clutch pedal that simply allows the vehicle to coast with regenerative breaking disabled sounds like the best compromise to me.

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If memory serves from the test drives, the new Hyundai/Kia electric vehicles (built on a common platform) have paddle shifters that only manage regenerative braking, similar to how you would use engine braking.

One of the subtler features of my DSG vehicle is that on most downhills it will automatically downshift to maintain speed. On a really steep hill it will start to race, but feathering the brake for 5-10 seconds will convince it to downshift once more. I haven't driven it in the mountains hardly ever, but that's one area where manuals often win out - no melted brake pads, no heat-warped calipers.

In fact I put way more miles on the first set of brake shoes on this car than I would have dreamed possible, to the point I started having mechanics check their records to make sure we didn't change them while it was in for something else.

Nice thing with EVs is that with regenerative breaking you barely use the brakes at all. When I hade mine in for regular service interval the mechanic told me to do some hard brakes from time to time to keep rust off the brakes!

> Nice thing with EVs is that with regenerative breaking you barely use the brakes at all.

Some cars have enough regen braking that you don't need the brakes at all except for emergency braking, though usually it's an opt-in mode. Look for something like "one-pedal" or "single-pedal". Sometimes it's a physical button with a foot (not) pressing a pedal.

> One of the subtler features of my DSG vehicle is that on most downhills it will automatically downshift to maintain speed. On a really steep hill it will start to race, but feathering the brake for 5-10 seconds will convince it to downshift once more. I haven't driven it in the mountains hardly ever, but that's one area where manuals often win out - no melted brake pads, no heat-warped calipers.

Can't you just tell the car to downshift using paddles, or force it into low gear using a gear limiter feature?

DSGs start at 6 gears and go up from there. Paddle shifters and DSG are also not synonymous. Mine and a few other more recent designs I’ve seen have a gearshift that looks like an automatic but it goes sideways into a gear selector. Many won’t use that mode.

Yes you could do this fully manual but you get more fleet efficiency if it’s automatic.

My point was that most (if possibly not all) ATs let you limit the gearing to use engine braking when going downhill.

Sounds like it would work fine for you if you but used it. “More fleet efficiency” is not a huge concern on downhills, you just switch back to the automatic regime when you’re at the bottom.

if your only use case is to disengage the regen braking you should probably just have a regen braking disable function, a clutch is an awfully complicated way to achieve that. You could literally have a software 'clutch' pedal that did nothing other than disable the regen if that was your goal.

Although on the other hand the clutch does have a nice property, which is that it works regardless of the state of the control system of the vehicle. If my MCU decides it wants to accelerate me at 500 mph into a wall a hardware clutch would be a nice thing to have!

W.r.t gearboxes in EVs: there is definitely a reason to have a transmission in an EV, it's just that most manufacturers don't include one for simplicity .

https://i.stack.imgur.com/HRUva.gif

That's what I meant. One thing I appreciate about a manual transmission car with its clutch pedal is the ability to coast, not accelerating but not slowing down like regenerative braking would.

Agreed I want the ability to smoothly switch between coasting and different levels of regen in an EV. A clutch pedal would be a cool way to do it. I've imagined a large dial or lever where a shifter would normally be.

You're correct; Teslas (and most EVs) have a gear reduction but no ability to change any gears, since they don't really need to. Coasting comes by feathering the accelerator, similar to how you can slowly decelerate in a manual transmission.

https://www.youtube.com/watch?v=zsa-SxpiCU0 has Ken Block talking about how different driving a high performance EV is, though, since you have full wheel speed range without shifting. On one hand, you don't need to work a clutch to keep turbos spooled up; on the other, you have to be much more precise because you can't let the clutch slip for additional control.

In consumer EVs, though, the car won't really let your wheels slip.

So here's a crazy idea: Keep the third pedal, and have it adjust the sensitivity of the accelerator pedal.

While we're at it, put force feedback on gas pedal, when wheels start slipping make it gently push on the driver's feet so they can "feel" the grip.

Heh. Fortunately, there's already force feedback in how the car moves when the you start to lose grip.

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