We’ve got used to gear boxes. We know how to use them and some people are not able to drive a car without one. It’s like we need them. It’s part of the driving experience. But, do we really know why they exists?
Combustion engines are very inefficient. About 80% of the energy generated is transformed into heat and the other 20% goes into the real movement of the car. And part of this energy is lost in the gear box. So every time you fill the tank you must know that just a tiny bit of the fuel is really going to move the car.
Now, why is this related with the gear boxes? The strength of combustion engines is also different depending on how deep you are pressing the gas pedal, the speed you are going and the current gear. The gearbox really affects the energy consumption of the vehicle, since it regulates engine revolutions according to the speed of the car. RPM is nothing else than “explosions per minute”. The higher the RPM is, the most explosions you have, the more gasoline you consume.
Electric motors are different. There are at minimum 90% efficient. It also has his maximum strength in every point without needing a gear box, it means that there is no need to administer different speeds of the motor with gears.
So in theory there is no need to have a gear box in an electric car. But there is one exception: If you want to drive fast you can brake the engine. The Tesla Roadster has 2 gears, one for “normal driving” and the other for “racing”. But there is a difference with normal cars; you can even start moving in the second gear, and still have a huge acceleration.
If you have any questions about electric cars, just let us know your comments.