Hello Guys today I will explain why electric cars have only one gear, when compared to 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 different level, there are other car companies also building electric cars, like Nissan, BMW, Audi and Rimac. These are the companies in global market. In India Mahindra e2o is present for a 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 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 has 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 high rev range, having transmission on these cars means putting more weight, cost and more complexity and it will lose its efficiency.
Electric motor can be geared specifically for any given top speed. But when compared to electric car, gasoline engine need multiple gears to reach the top speed. All electric car is set at 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 benefit 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 cars, use gears. Because more aggressive gear will spin the wheel faster and you will have more wheel torque. You will reach the peak power faster when compared to 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 advantage with multiple gears. Whereas big electric motors with higher torque can do better with 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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