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Design of a Lightweight Braking System for Electric Cars
ISSN: 0148-7191, e-ISSN: 2688-3627
Published February 01, 1992 by SAE International in United States
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As the community is becoming more and more aware and conscious of the pollution problems caused by the internal combustion engine and its use in transportation, we are now seeing the first projects and prototypes regarding hybrid and electrically-powered vehicles.
One of the main problems witnessed by engineers has been that of the relatively low operating range provided by the storage batteries available on the market today, and so, recovering the energy that is inevitably lost during braking is of primary importance.
The concept of regenerative braking is fairly simple as it consists in making the electric motors function as generators.
In many of today's applications we find two indipendent controls for the operation of the hydraulic brake and for the activation of regenerative braking. The choice on which braking mode to use, or in which sequence the two modes are to be used is left to the driver who, at the onset of braking, is forced to make mental considerations in order to activate the two braking modes in the right sequence. Furthermore, the driver must not forget to disable the regenerative function at the end of each stop.
BREMBO has designed a braking system in which a single control, that is, the brake pedal, activates and disables in the right sequence the two different braking modes, thus allowing:
to maximize energy recovery by the electric motors each time the driver steps on the brake pedal;
the hydraulic brake to be used in addition to regenerative braking when the latter is not enough to produce the required deceleration.
The proposed braking system is lightweight and versatile. It can be adapted to the different powertrain configurations seen on various electric vehicles.