eli5 why ev car can’t make manual transmission. the real manual transmission that have clutch and so on.?


eli5 why ev car can’t make manual transmission. the real manual transmission that have clutch and so on.?

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They can, it’s just useless. It makes the car less efficient, less reliable, more confusing to drive, and heavier. Electric cars don’t need much of a transmission because electric motors are so much more flexible than engines.

There is no point.

A combustion engine only produces peak engine torque at a narrow range of engine speeds, so you need a transmission in order to be able to drive the car at the full range of speeds needed to drive on the roads. You literally couldn’t drive a combustion engine if it didn’t have a gearbox – a gear ratio of 1:1 is somewhere between 3rd and 4th gear on a manual, so you wouldn’t be able to start the car from a standstill.

Electric engines don’t need gears, because they produce useful torque at all engine speeds. Adding a gearbox is just adding weight and complexity and cost.

They don’t need them.

Transmissions are needed for internal combustion engine cars because ICE motors need to maintain certain RPMs to produce useful power. This is often a range of about 1000 to 7000 RPM… and worse yet the best power and best efficiency are at even smaller ranges (and those aren’t the *same* ranges).

The solution to this is to have multiple ratios of engine to wheel speed; 1st gets you moving from a dead stop and the top gear is for cruising at ~2000 RPM at highway speeds.

Electric motors don’t need this because they have a (nearly) ‘flat’ power curve; you can start from a dead stop, accelerate, and cruise at highways speeds all with the same gear ratio.

That would be totally useless. My Tesla can go from 0-155 MPH using a single simple reduction gear. Adding a clutch or transmission would add hundreds or thousands of additional parts for absolutely no benefit.

They can, they have, and there are some planned to come out in the future. The original Tesla and the Porsche Taycan had a tow gear gear box. A few conversions have also left the clutch attached to the original manual transmission and it works fine.

The fact is, they just don’t need it – and extra weight means decreased range – so out it goes.

But, why doesn’t an electric require a transmission and clutch?

Transmission: When a gas engine runs too slow, it dies. When it runs too fast, it can overheat or break. This range of RPMS (how fast its running) is surprisingly narrow. A transmission allows the ratio of wheel speed to engine speed to change to stay in this narrow range (this is why modern CVTs are so efficient, the V is for “variable” as it can set whatever the appropriate ratio is, like an infinite number of gears without the added weight.) An electric engine, however, can run at max speed or a complete crawl without too much issue. Additionally, a lot of “AWD” electrics can house two motors – one running the front, another running the back wheels, and each “geared” differently to be more efficient at higher or lower speeds, and then adjusting where the car’s power goes based on what is needed (for instance, the front wheels may be more efficient at higher speeds, while the rear gives more power at lower speeds and shuts off at highway speeds for maximum efficiency).

Clutch: The clutch is there to disconnect your driveshaft from the engine. In a gas car, this prevents the car from stalling if the speed of the wheels gets too slow for the engine to run. You then choose an appropriate gear for your speed and adjust the engine’s RPMs to the appropriate speed to drop the clutch back into gear. Remember, an electric engine doesn’t stall at slow speeds and can run REALLY fast – so this just isn’t necessary, you could just shift gears with an electric (and in fact a few race cars were setup this way).

IN the end though, the whole gear system does have a loss of energy in it. You want your engine as directly connected to the wheels as you can, and adding gears and clutches is moving in the opposite direction while not adding anything.

That said, there are rumors of a few companies planning on including a shifter in some high-end electric cars – but it would probably just be a gimmick as opposed to a mechanical advantage.

As a weird side note: EVs don’t need a reverse gear. The engine can just run in reverse. So, unlike a gas powered car, an EV (technically) can drive as fast backwards as it can forwards.