regenerative braking system and it_s uses in[1]

8/4/2019 Regenerative Braking System and It_s Uses in[1]

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By

P.VenugopalRaju

3pg07me029



Introduction Conventional Breaking System

Regenerative Breaking & Its Working

Kinetic Energy Recovery System(K.E.R.S) Discharge mode of K. E. R. S

Benefits of Regenerative Breaking System

Limitations of Regenerative Breaking System

Conclusion

Reference



What are brakes? A brake is a device that decelerates a

moving object / prevents an object

from accelerating.

Brakes use friction to convert kinetic

energy into heat

Guiding principle- kinetic energy

increases quadratic ally with velocity -

K = mv2 / 2

When the brake is pushed the calipercontaining piston pushes the pad

towards the brake disc which slows the

wheel down.



Convectional braking system Conventional braking

systems use friction to

counteract the forward

momentum of a moving

car.

As the brake pads rub

against the wheels,

excessive heat energy is

created. This heat energy

dissipates into the air,

wasting up to 30% of the

car's generated power

http://www.wisegeek.com/what-are-brake-pads.htm






Regenerative braking

Regenerative braking technology funnels the energy created by the

braking process back into the system in the form of charging the

battery for further use

In a regenerative braking system the energy normally lost in the

braking process is transferred to the generator from the rotating axel

and then transferred to the battery, thus saving energy



How does it work

The system that drives the vehicle does the majority of the braking. When the driver steps

on the brake pedal of an electric or hybrid vehicle, these types of brakes put the vehicle's

electric motor into reverse mode, causing it to run backwards, thus slowing the car's

wheels. While running backwards, the motor also acts as an electric generator, producing

electricity that's then fed into the vehicle's batteries.



Vehicles driven by electric

motors use the motor as a

generator when using

regenerative braking: it is

operated as a generator during

braking and its output is

supplied to an electrical load;

the transfer of energy to the

load provides the braking

effect.

Many modern hybrid andelectric vehicles use this

technique to extend the range

of the battery pack.



v v

Motor

IC Engine

Generator Battery

Wheel

Wheel

Motor

Transmission

IC Engine

Generator Battery

Wheel

Wheel

Motor

Transmission

IC Engine

Generator Battery

Wheel

Wheel

Scenario 1: Low speed - Power isprovided by electric motor using energy supplied by the DC battery

Scenario 2: Braking – Kinetic energy isconverted to electric energy duringregenerative braking by electric motorand supplied to battery.

Scenario 3: High speed – Power isprovided by IC engine and electric motor

via generator. Generator also chargebattery during high speed.

Over view



Kinetic energy recovery system

The device recovers the

kinetic energy that is

present in the waste heat

created by the car’s brakingprocess.

The concept of transferring

the vehicle’s kinetic energy

using Flywheel energy storage was postulated by

physicist Richard Feynman

in the 1950s



How does K. E.R. S work



When the driver brakes most of the kinetic energy is still converted to

heat energy but a portion is treated differently and is stored up in the

car.

When the driver presses his boost button that stored energy is

converted back into kinetic energy

The mechanical KERS system utilises flywheel technology to recover

and store a moving vehicle’s kinetic energy which is otherwise wasted

when the vehicle is decelerated.



Flywheel of K. E . R. S

Made of steel and carbon fibre

which rotates at over 60,000 RPM.

60 kW power transmission in

either storage or recovery

400 kJ of usable storage



Discharge mode of K. E. R. S



During this stage when the driver pushes the boost button the flywheelacts as a propulsion motor and discharges the energy to the wheels

The Flywheel rotor is decelerated during boost discharge mode and the

energy is converted back.

Flywheel acts as a generator and sending energy back to electric motor,

which works as propulsion motor.



Benefits of regenerative braking

Reduction of pollution

Increase in engine life Breaking is not total loss

Wear Reduction



Reduction in pollutionRailway vehicle – The Delhi Metro saved around 90,000 tons of carbon

dioxide (CO2) from being released into the atmosphere by regenerating

112,500 megawatt hours of electricity through the use of regenerative

braking systems

Regenerative brakes have been able to improve the performance of engines.

This has been exhibited in the Motor sport industry –The system used by F! cars

is called K. E. R. S (Kinetic Energy Recovery System)

Increase engine efficiency



Breaking is not total lossConventional brakes apply friction to convert a vehicle’s kinetic energy

into heat. In energy terms, therefore, braking is a total loss: once heat isgenerated, it is very difficult to reuse. The regenerative braking system,however, slows a vehicle down in a different way.

Wear Reduction An electric drive train also allows for regenerative breaking whichincreases Efficiency and reduces wear on the vehicle brakes.



Limitations of regenerative braking

system The regenerative braking effect drops off at lower speeds, therefore the

friction brake is still required in order to bring the vehicle to a complete

halt.

The friction brake is a necessary back-up in the event of failure of the

regenerative brake.

Most road vehicles with regenerative braking only have power on some

wheels (as in a 2WD car) and regenerative braking power only applies tosuch wheels, so in order to provide controlled braking under difficult

conditions (such as in wet roads) friction based braking is necessary on the

other wheels



Conclusion

The energy efficiency of a conventional brake is only about 20percent, with the remaining 80 percent of its energy beingconverted to heat through friction. The miraculous thingabout regenerative braking is that it may be able to capture as

much as half of that wasted energy and put it back to work.This reduces fuel consumption by 10 to 25 percent.

Hence regenerative braking plays an important role in fuelconsumption and also in the field of speed



Thank you

regenerative braking system and it_s uses in[1]

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