INDIA TIMES: Riding a bicycle is a very good form of exercise. You pedal, you brake, you pedal again. The calories burnt to provide the energy required to move the bicycle is what keeps you fit. But did you know that the energy that moves the bicycle is lost when you apply the brakes?
You see, in conventional brakes, most of the energy of the moving vehicle is lost in the form of heat. What if we could conserve this energy? Or at least recover a part of it and maybe use it to power the vehicle yet again. Well that is what is being done now, using a system called ‘regenerative braking’. Used in electric and hybrid cars, regenerative braking is able to conserve some of the energy released during braking and transfers it back to the car’s battery, thus increasing the range of the vehicle. Efficient, right?
Now Honda is taking it a step further. It is making it sort of a mandate in its upcoming (and first ever) electric car – Honda E. A concept car for an urban commute at first, Honda E has finally taken shape into a production car, a car that will come with a single pedal system.
As can be guessed from its name, a single pedal system bestows most of the operations associated with driving a car on a single pedal – the accelerator. To be clear, such electric cars will have a dedicated brake, only that it won’t be used much because the regular braking will be performed just by lifting your foot from the accelerator.
The working is quite simple actually. You press on the pedal to accelerate and when you have to brake, you simply lift your foot off it. In essence, a single pedal system uses regenerative braking to work. So as soon as you lift off your foot from the pedal, the regenerative braking kicks into action, thus slowing down the car for you.
To understand the workings of regenerative braking, let us recall the concepts of an electric motor and a generator. An electric car is powered by an induction motor, which rotates to move the car forward, i.e. it converts electrical energy into mechanical one. Interestingly, the same motor can also act as a generator, producing electricity from mechanical energy.
At the time of braking, the electric supply to the motor is cut and instead, the mechanical energy of the car powers the motor (now acting as a generator) to produce electricity, which is then fed back to the battery and thus helps in extending the range of the car.
The primary benefit of the single pedal system is the regenerative braking system it employs. While it does recharge the battery every time you brake, keep in mind that it also starts braking on its own every time you take your foot off the pedal.
Now take an example of a car moving at 60 kmph. In a conventional vehicle, leaving the pedal would mean that the vehicle will coast close to the speed until the friction and air drag eventually bring it to a halt. So even if you want to cruise at a steady speed, you can lift your foot off the pedal intermittently.
In a vehicle like the Honde E though, where lifting your foot from the pedal would initiate the regenerative braking, the car will come to a halt much faster than the previous instance. There is no doubt that some energy will be conserved through the braking and added back to the battery. But you will also need the same (practically more) energy to get the car moving at the same speed again i.e. if the speed drops to 40 kmph within 10 seconds of lifting your foot, you will have to accelerate yet again to reach back at the 60 kmph mark.