Hello, Guys today I will explain why electric cars have only one gear when compared to the internal combustion engine. That does not mean there are no gears in electric cars, according to some people misconception.
Electric cars are getting popular day by day. With Tesla taking electric cars to a different level, there are other car companies also building electric cars, like Nissan, BMW, Audi and Rimac. These are the companies in the global market. In India, Mahindra e2o is present for quite a while. Tata has begun production of Tigor EV. But surely it will take time for India to have a good electric car market.
Why do Electric cars have one Gear?
- The main reason is the high revving electric motor. Electric motors can rev around 10000 rpm in a normal daily running electric car, which is very high compared to an internal combustion engine. Formula E cars rev around 20000 RPM and have a top speed of 225 Kmph.
- The power is efficiently spread across a broad rpm range.
- High torque generation at low rpm. Low as 0 rpm.
- Because of the high rev range, having transmission on these cars means putting more weight, cost and more complexity and it will lose its efficiency.
The electric motor can be geared specifically for any given top speed. But when compared to an electric car, the gasoline engine needs multiple gears to reach the top speed. The all-electric car is set at a different top speed. The normal road electric cars are limited to 160 kmph.
Some of these cars have a couple of gears. In formula E, 3-speed electric car was used. So what is the benefit of having gears?
Benefits of having gears
In formula E the power is limited to 170 KW. Power increases gradually to the limit, but at low-speed, the power is not completely used which decreases the acceleration. To overcome the low acceleration this electric car, use gears. Because more aggressive gear will spin the wheel faster and you will have more wheel torque. You will reach peak power faster when compared to a single gear electric motor.
It also depends on the size of the electric motor and the torque it is generating. Smaller motor with low torque will have an advantage with multiple gears. Whereas big electric motors with higher torque can do better with a single gear.
Watch this video by Engineering Explained, he explains it beautifully. He has made this video in partnership with Formula E.
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Also published on Medium.