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Regenerative braking systems are growing in popularity as a fuel saving technology. They use an electric motor or alternator to generate electricity as the vehicle decelerates, thereby recovering a portion of the vehicle's kinetic energy. Regenerative braking systems in hybrid vehicles generally use a large electric motor and dedicated battery. Compared to batteries, capacitors can be charged and discharged rapidly and are resistant to deterioration through prolonged use.
According to Mazda, i-ELOOP efficiently converts the vehicle's kinetic energy into electricity as it decelerates, and uses the electricity to power the climate control, audio system and numerous other electrical components. The company said it examined numerous automobile accelerating and decelerating mechanisms, and developed a highly efficient regenerative braking system that rapidly recovers a large amount of electricity every time the vehicle decelerates. Unlike hybrids, Mazda's system also avoids the need for a dedicated electric motor and battery.
Its i-ELOOP system features a new 12- to 25-volt variable voltage alternator, a low-resistance electric double-layer capacitor and a DC/DC converter. The system starts to recover kinetic energy the moment the driver lifts off the accelerator pedal and the vehicle begins to decelerate. The variable voltage alternator generates electricity at up to 25 volts for maximum efficiency before sending it to the capacitor for storage. The capacitor, which has been specially developed for use in a vehicle, reportedly can be fully charged in seconds.
The DC/DC converter steps down the electricity from 25 volts to 12 volts before it is distributed directly to the vehicle's electrical components. The system also charges the vehicle battery as necessary. I-ELOOP operates whenever the vehicle decelerates, reducing the need for the engine to burn extra fuel to generate electricity. That is how, in "stop-and-go" driving conditions, fuel economy can improve by approximately 10%. The name "i-ELOOP" is an adaptation of "Intelligent Energy Loop" and represents Mazda's intention to efficiently cycle energy in an intelligent way.