Energy
Wednesday, August 17th, 2022 6:10 am EDT
A recent interview at Top Gear came up with an unexpected nugget of EV news: Lexus is considering building an EV at some point in the future with a manual transmission. The catch? It won’t be a real manual transmission if it happens. Instead, it’ll be a simulated shift lever and a simulated clutch pedal.
In the interview, two key things stand out for CleanTech fanatics. For one, Lexus is a Toyota company, and, well, Toyota is known for not building EVs much. The company is hoping for better battery technology and better infrastructure before it goes all in on EVs, and even then expect PHEVs, hydrogen fuel cell cars, and other forms of electrification to be around from Toyota for a long time. So, the idea that it’s going to up and build an EV, especially in the form of a supercar, seems suspect.
But, if solid-state battery technology takes off (Toyota claims to be far along in cracking that technology), the weight savings would make it a good fit for an EV.
The other nugget about a simulated manual comes from this quote:
“Then he drops a little bombshell. He’s experimenting with some sort of simulation of a ‘manual’ transmission, done through software. “It’s a hobby of mine, a crazy thing. I’m looking for better engagement, even in an EV, I want another link from the car to the driver. It’s not just about efficiency. I love cars and want something different.””
Why A Real Manual Would Actually Make Sense
I know, I know. EVs have one gear, and that’s great for simplicity. Tesla proves out that you can get away with not needing additional gears, too, right? I’ve written about this before, and, not so much.
The electric motors in EVs don’t need a multi-speed transmission because they can operate over a wide range of speeds. At the lower end, they can go all the way to 0 RPM without stalling. There’s no need to idle, and when you hit the skinny pedal, full power is available. Most EV motors can go beyond 10,000 RPM at top speed without damage. With few moving parts, they don’t fly to pieces at those speeds, either.
Though, there is one problem. Electric motors do not generate the same torque from zero to maximum RPM. They all put out full power until a certain speed; then their torque begins gradually decreasing. Efficiency also varies speeds that the motor is capable of going. The sweet spot, where they are most efficient, ranges around ⅓ to ½ power at 30–40 MPH (50–65 km/h).
Even though an EV will operate from 0 RPM to the max speed of the motor, it won’t have as much power or range if its single gear is only meant for city driving.Fixing this by making the gear “taller” could theoretically help, but then the car’s performance and efficiency would drop in city conditions.
Most people are unaware that Tesla’s original plan for the Roadster was to have a 2-speed gearbox. This would provide optimized performance by having a lower gear for initial acceleration and then transitioning into a higher gear once the desired speed was reached. However, when compared to other EVs in development at the time, such as the Nissan LEAF with its 94 MPH (151 km/h) top speed or Chevrolet Volt which achieved around 101 MPH, it became clear that this idea wasn’t feasible.
The trouble was that Tesla couldn’t manage to create a multi-speed gearbox able to bear the torque of an electric motor. It was already struggling with cost delays, and had no choice but to give up on the multiple speed transmission. However, work on the “Whitestar” prototype for the Model S gave it another idea: by improving power electronics, it could stuff more electrons into it to make an even longer torque curve (i.e., more speed).
The inefficiency of that approach, however, is evident. Using more power to improve the performance tradeoff might work in theory, but it’s not feasible because current battery technology wouldn’t be able to support it for very long.
Tesla discovered that the best way to use two gears was by placing one in the back and another in the front. This created a powerful car that could maintain speed on highways while also being able alter power when necessary for city driving. Tesla’s implementation of dual motor drive units allow its cars, such as Models S, X, and 3, to have different gear ratios depending on whether it is needed for lower or higher speeds. In “range mode,” the computer directs more power toward the drive unit with the gearing that best fits the situation when cruising on the highway.
So, many Tesla vehicles do in fact have multiple gears and do get better range and performance by doing this. So, having a simulated manual instead of a real one would make less sense, because EVs can really benefit from having multiple gears.
Jeep Did This With A Prototype
EVs with manual transmissions are actually nothing new. Home-built EV conversions often go this route to avoid the problems that would accompany automatic transmissions. Plus, Jeep has done this with a modern EV, too.
The 2020 Jeep Wrangler Magneto prototype looks like any other 2020 Jeep Wrangler on the outside, except for one small detail: there are “Magneto” decals on the side of the hood. Underneath that hood is something no production 2020 Jeep has: a powerful electric motor. This custom-built axial flux electric motor operates up to 6,000rpm — which is actually low compared to most EVs (a Nissan LEAF operates above 10,000 RPM at high speeds and Teslas can go as fast as 18,000). However, in this case it doesn’t matter because Jeep coupled the motor to one of easiest-to-drive manual transmissions ever designed.
If you don’t want to shift, most manual EVs don’t require it. Many EV conversion projects employ a manual gearbox, and for those drivers, the majority of the time, it’s left in 2nd gear. When approaching a red light, you may simply allow the RPM to decrease (electric motors do not stall). When ready to take off, simply press the accelerator until it clicks into place. There’s no need to slip the clutch when climbing over things or keep the clutch pedal pressed while waiting for the green light to change.
There’s No Reason To Simulate What Would Benefit The Car
Ultimately, the ease of operating a manual EV and the efficiency and performance benefits make it a great idea. It really doesn’t make sense for a performance car to simulate a manual transmission when a real one could be put in and work great.
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