A NEW suspension system proposedby Audi, the eROT, replaceshydraulic dampers (shock absorbers)with rotary ones tha convertmechanicalmovements from speedbumps and undulations on the roadto electrical energy. The eROT comprisestwo horizontally arranged electric motors on the rear axle. These convert the vibration energy into electrical energy and feed it to a 48-volt subsystem that aids the car’s primary 12-volt system, which runs driver assists, the air conditioning and other electronic equipment.
To learn how the mechanicalelectrical energy conversionin the eROT happens, you have to understand the basic working of a suspension system. To put it simply, when you drive over a bump, the damping system (imagine it in the form of spring) gets compressed and stores
the energy. This is called the ‘compression stroke’. Once you pass that bump, the ‘spring’ uncoils and dissipates the stored energy during
the ‘rebound stroke’. These two movements are mutually dependent on each other. However, in the eROT, these two motions become
independent of each other, thanks to a software that actively controls the strokes. During the rebound, the kinetic energy—in the form of transverse movement of the wheel carrier— is used to actuate a lever arm, which transmits the energy via an intricate system of gears to an
electric generator, where it is converted to electricity. On the general ly wel l -paved highways i n Germany, the electrical output recorded by Audi was around 100- 150 watts and the car maker even claims the technology could reduce carbon dioxide emissions by around three kilos per kilometre.
—Agrima Joshua @agrimonious