The Advent of Regenerative Braking

THE IDEA of a brake that could take the kinetic energy it absorbs and turn it into potential energy for later use has been around since the late 1800s. Some of the early attempts of this technology were to install spring type RBS (Regenerative Braking System) on front wheel drive bicycles or horse-drawn cabs.

Over in Russia, the BakuTbilisi-Batumi railway started applying RBS in the early 1930s. This is one example of early using of this technology in railway system.

In the 1950s, Swiss company Oerlikon developed the gyrobus, which used the flywheel as its energy storage method. The effects of gyroscopic motion on the bus soon resulted in it being discontinued.

In 1967, the American Motor Car Company (AMC) created an electrical energy regeneration brake for their concept electric car, the AMC Amitron. Toyota was the first car manufacturer to commercialise RBS technology in their Prius series hybrid cars.

Since then, RBSs have evolved to be used in almost all electric and hybrid cars, as well as some gas-powered vehicles.

Currently, the most commonly used method of regenerating power is the electromagnetic system.

In the electromagnetic system, the drive shaft of the vehicles is connected to an electric generator, which uses magnetic fields to restrict the rotation of the drive shaft, slowing the vehicle and generating electricity.

In the case of electric and hybrid vehicles, the electricity generated is sent to the batteries, giving them a recharge. In gas powered vehicles, the electricity can be used to power the cars electronics or sent to a battery where it can later used to give the vehicle an extra boost of power.

In flywheel RBS, the system collects the kinetic energy of the vehicle to spin a flywheel that is connected to the drive shaft through a transmission and gear box. The spinning flywheel can then provide torque to the drive shaft, giving the vehicle a power boost.

Electro flywheel regenerative brake is a hybrid model of electromagnetic and flywheel RBSs. It shares the basic power generation methods with the electromagnetic system; however, the energy is stored in a flywheel rather than in batteries.

The spring loaded regenerative braking system is typically used on human powered vehicles, such as bicycles or wheelchairs. In spring RBS, a coil or spring is winded around a cone during braking to store energy in the form of elastic potential. The potential can then be returned to assist the driver while going up hill or over rough terrain.

The hydraulic RBS slows the vehicle by generating electricity which is then used to compress a fluid. Nitrogen gas is often chosen as the working fluid. Hydraulic RBSs have the longest energy storage capability of any system, as compressed fluid does not dissipate energy over time. However, compressing gas with a pump is a slow process and severely limits the power of the hydraulic RBS.

Modern hybrid and electric cars both use an electric engine to power the car which makes applying regenerative braking very simple and efficient.

In most of these cars, the transmission of the car is set up such that when the driver applies the brakes, the electric motor reverses itself and applies a resistance to the wheels rather than power.

In high performance electric cars, improving the feel of the car is very important. Many customers support electric super-cars but are against purchasing them because of the lack of high performance feel. One important aspect of this feel is engine braking. In a standard internal combustion engine, once power is not being applied to the engine, the natural friction inside the engine works to slow the vehicle down.

In electric cars, this friction force does not apply; however, car companies such as Mercedes and Porsche have begun to use regenerative braking systems to give the driver the same feel of a gaspowered car while recovering energy for the batteries. 1. The best-selling electric car in the US is the___ _______. a) Tesla Model 3 b) Chevrolet Bolt c) Nissan Leaf

2. The best-selling car brand in Japan is___. a) Honda b) Toyota c) Nissan

3. The best-selling foreign car brand in Malaysia is____. a) Toyota b) Honda c) Nissan

4. Over the past decade, the cheapest production car in the world was the____. a) Maruti Suzuki 800 b) Cherry QQ c) Tata Nano