OT: Brakes seizing on electric cars? (2024 Update)

[Xeno]

Way before that concept appeared on the scene.

[Xeno]

It has become quite clear to me that all this is going right over *your* head. Your idea that gears are approximately equal ratios is wrong. The gear ratios are selected at the design stage to suit the torque and power curves of the engine countered by the mass of the vehicle. Get this, the torque converter does not endow an auto with a magical low gear. It simply multiplies torque through a regenerative process. It does this at any time the engine is under power acceleration and in any and every gear.

Like I've said, that is but an attempt to make the trans foolproof. I have noted, however, fools are very ingenious and can wreck anything they turn their hands to.

Not at all. You would be surprised at the number of people out there who fail miserably to understand the concept of economical driving. You have indicated by your response above that you are one such person.

It ain't that simple.

If you drive in a manner that would cause you to require first whilst at a speed where you are rolling along in 4th, I'd suggest it might be time to hand in your driver's licence.

[Dave Plowman (News]

Think, with epicyclic autos, you don't have the same choice of ratios as you can have with a manual box. Unless you increase the number of epicyclic gear sets. The Rolls 4 speed - used in the 50s and 60s - had rather odd ratios. Not evenly spaced at all. Later four speed units are simply a 3 speed with effectively an overdrive added. Once 5 speed autos arrived, they seemed to provide 5 reasonably well chosen ratios.

Remember seeing a Met police spec Rover P6 3500 auto. The selector mechanism had been modified to prevent it being locked in 1st gear. Now on that BW 35 version, you couldn't select 1st above a fairly modest speed anyway. But move off from rest with it locked in 1st, and it would stay in

1st regardless.

[Commander Kinsey]

We haven't always had hazard lights? Or are you only talking about racing?

[Rod Speed]

Correct, the VW beetle didn't have them.

Or are you only talking about racing?

[Commander Kinsey]

That's what happens when automation tries to help without having enough information. It was trying to be helpful but made things worse. Imagine trying to drive with one person operating the wheel, one the pedals, one the handbrake and indicators.

The answer to all that paragraph is.... French electrics.

[Commander Kinsey]

Doesn't bother me as I never use any type of handbrake. Park in gear and turn the wheels against the kerb. Hill start using the footbrake.

[Xeno]

Each epicyclic gear train is capable of the following; low reduction, fast overdrive, moderate reduction, moderate overdrive, reverse reduction, reverse overdrive, direct drive and, finally, neutral. They are then compounded to give extra. My wife's Suzuki, for instance, has an Aisin 441 4 speed auto. It uses a Ravineax compound gearset where 4th is overdrive. Very much like the old Borg Warner 35 with added overdrive. The 9 speed 9G-Tronic from Benz only has 4 planetary gearsets to achieve

9 forward speeds plus reverse. That gives the transmission a very wide 9.15 ratio spread. That enables an engine with a relatively narrow power band to always remain in the *sweet spot* for either optimum performance or optimum economy.

An interesting point with the ZF 9 speed, as used in the Jeep, is that

5th gear is *direct* and 6 through 9 are *all overdrive ratios*, such is the state of play with *mandated* fuel economy demands. Note, both these transmissions will be used with lock up TCs giving a pseudo 10th ratio as well. How much difference the TC lockup will make depends a lot on the torque converter's capacity. It can equate to as little as 100 rpm difference in engine speed to as much as 400+ when locked up.

The ratios are chosen with regard to the engine performance and the expected use of the vehicle. If the ratios aren't ideal, the slack can be taken up by the torque converter capacity.

You have boy racer cops there too, huh?

Some autos don't even give the option of Lock 1.

[Commander Kinsey]

He didn't say that. He said he didn't use the brakes. He might press the brake pedal, but on an electric car that should engage regen before the actual brakes. Real brakes are only used if you press hard on the pedal.

You can apparently adjust what it does when you let go of the gas. But unless the designer is monumentally stupid, no matter what your setting is, braking means regen THEN brake pads. No point in using pads when you could be charging the battery.

[Commander Kinsey]

Done it and it was identical to a manual. VW Golf 1.9l TDI Mk 4, 1998.

What is an "overrun"?

[Commander Kinsey]

If you're going at speed, then the revs don't drop, it behaves just like a manual. But if you're going slowly in town, then they do, but that's because it goes up a gear, not into neutral.

[Commander Kinsey]

I'm surprised anything different is even allowed, yet you can set some cars so letting go of both pedals causes heavy regen braking. Not sure if it activates the brake lights, but it's going to cause an accident. I'd never set my car that way. What if you want to lift your foot to scratch an itch?

[Commander Kinsey]

What's In Car Entertainment to do with it? If I buy a car from a private seller and it says ICE in the ad, I expect a good stereo.

[Commander Kinsey]

Solid state batteries coming soon? 5 times the capacity, lifetime, cheapness, and recharging speed.

What were you driving, an original Mini? Only auto car I've ever seen do that. Oh and a Rover 75. Hmmm, both British shit. Every other auto changes absolutely smoothly using the torque convertor. Sometimes you can't even tell it changed gear apart from the rev counter moving and bit more noise.

See above, just didn't happen with mine.

Then you come across something unexpected and mess about wasting time with the gears. Manuals suck. Autos are great for overtaking too, you don't have to get in a lower gear ready for that tiny gap, you just press the pedal when ready.

Except then you lose the weird government subsidy where you (if they still do this) get paid for what you generate, not what you give to the grid. So: Sunny day, feed to grid, get paid. Sunny day, charge car during the day, get paid for charging the car! Sunny day, charge car overnight, get paid but then buy it back at a higher price.

[Commander Kinsey]

Ouch, last time I checked it was more like £3000, or is that a hybrid battery?

Are they? I've not found any under 6 to 8 grand. I can get a petrol car with a year's MOT for £500! So, several grand to buy it 2nd hand, several grand to buy another battery, how long before I would have used 14 grand of petrol? Not economical whatsoever.

[Commander Kinsey]

Depends how you drive, presumably it's similar to mpg on petrol cars, it's variable. My golf said it got 45mpg. I could get anything from 23 to 58. 23 was fun, 58 held up truckers.

[Commander Kinsey]

I never had to adjust any of mine.

Worst one I ever drove was my neighbour's Rover 75 (2004). It felt like a learner driver was ramming in the next gear while forgetting to use the clutch. It actually made everyone in the car jolt forwards.

[Commander Kinsey]

No such things as kickdown. The car decides what gear to go into based on how far you've pushed the pedal. It could drop a gear (or more than one) a quarter of the way down, or half, or all the way down. Depends on the speed you're going and what gear you're currently in.

[Commander Kinsey]

More nanny state bullshit. If the government want us to use electric cars, they need to invent ones that are actually usable.

[Paul]

"EPA range of 517 miles"

Sounds usable.

Paul