Why do electric vehicles lack a gearbox, and how can they go as fast backward as forwards?

The popularity of electric vehicles, or EVs, is increasing, and the question “How different is the EV driving experience?” is often asked. Although there are several parallels, there are also some significant differences. We’ll show you how driving an electric vehicle differs from driving a traditional car in this collection of stories.

One of the most noticeable distinctions between most EVs and standard cars is the lack of a gear shifter, essentially because they only have one gear! The internal combustion engine of a diesel or gasoline-powered vehicle produces power and torque at varying RPMs (revolutions per minute), necessitating a gearbox with a variety of gear ratios to easily shift power to the driven wheels and maintain the engine in its “happy power band.”

However, since an electric motor does not need the combustion of fuel to produce electricity, it can provide full torque at zero RPM! These motors also have a wide RPM range, with the majority of them capable of revving up to 20,000 RPM! As a result of the constant torque transmitted over a wide RPM range, EV engineers don’t need to pair the motor with several gears, instead opting for a single-ratio, single-speed transmission that controls the electric motor and provides the optimal combination of acceleration and peak speed.

All the driver has to do after starting the motor is press a button or turn a dial to pick “D” for forward, “R” for reverse, and “P” for park. Some people may mistakenly believe that this is the same as driving a car with an automatic transmission or gearbox, but it is not. Multiple gears or speeds are chosen and changed automatically based on the friction on the accelerator or brake pedal in automatic transmissions. However, most EVs only have one gear, so there are no manual or automatic gear shifts. It’s also impossible to stall an EV because it just has one gear! It’s a huge help for inattentive drivers.

Many who like driving vehicles with manual transmissions, or even automatic transmissions, would definitely lose the sensation of the vehicle moving up and down via the gearbox. The driving environment in an EV is not entertaining, and the joy of smoothly changing gears with the clutch is also absent. It’s as simple as turning or pushing the drive selector, pressing the accelerator, and driving. And, since the electric motor is controlled by just one speed, EVs don’t even have a reverse gear!

This is because an electric motor can rotate in either a clockwise or anti-clockwise direction, and the direction in which it rotates decides whether the vehicle moves forward or backward. Reversing the motor’s rotational orientation is as simple as providing an electrical input through the drive selector switch or knob. The gear selector in a traditional car is a mechanical system that aids in gear shifting. The electric motor in an EV, on the other hand, is operated or governed by a sophisticated motor controller unit that receives inputs from the electric drive selector. This drive selector functions similarly to a smart input system in that it does not perform any mechanical functions but only electrically instructs the motor in which direction it should turn.

However, I’ve found that in some EVs, the relaying of this instruction can be delayed, resulting in a slight lag when transitioning from forward to reverse mode. So, if you click on the pedal right after pressing or rotating the smart selector, you could end up heading backwards instead of forwards, or vice versa.

Surprisingly, since there is no gear to regulate the direction, the acceleration in reverse is almost as rapid as it is forward! The electric motor will spin at the same speed in both directions, so the speed in reverse is only constrained by software. This means that once the speed limiter is disabled, an electric vehicle will travel almost as far back as it can forwards. Yes, an electric vehicle’s top speed can be reached in reverse! In reality, in 2012, stunt driver Terry Grant set a new “reverse run lap record” by driving an electric Nissan Leaf in reverse without the speed limiter at the famed Goodwood Festival of Speed Hill-Climb (1.6 km).

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