1 A SEMINAR ON DESIGN & ANALYSIS OF

REGENERATIVE BRAKING SYSTEM

UNDER THE GUIDANCE OF PROF. NILESH SHINDE

Presented by SHIVDATTA REDEKAR

NITIN SARGARSOHAIL SHAIKHBHARAT WAGH

2Identification of problem

Challenges across world on Climate change & Reducing Carbon Emission

Automotive industry's challenges- facing strict emission norms

The price increase of petroleum based fuel

Various research and development efforts for energy conservation & sustainable development methods

3Literature study • One third (21 to 24%) energy is

consumed during brake. • Research by Volkswagen has

shown that a hybrid drive with both ECE and ICE offers fuel saving of over 20% compared purely electric.

• A vehicle operated in the main city for such vehicles the wastage of energy by application of brake is about 60% to 65%.

Fig. shows energy utilization at wheels for heavy loaded truck and bus

4

Fig. shows energy dissipation on wheels during braking

Fig. shows the total braking force, regenerative braking force and braking force on front wheels

ENERGY DISSIPATION IN RBS

5FINDINGS IN LITERATURE STUDY

The average efficiency of energy recovery of the system was 66%. (HER)

Regarding to the energy recovering potential of the system, simulation results indicated that 32 to 66% of braking energy can be recuperated.

The variation is due to the losses of load variation. High potential of energy recovery and it is worth to apply for

commercial vehicle. (COURTESY: Journal of Science and Engineering Technology, Vol. 7, No.4, 2011)

6objectives

To study the basic design of RBS To identify obstacles occurred while implementing RBS To analyze RBS in terms of cost effectiveness, feasibility,

efficiency To carry out simulation in suitable software. To validate analyzed result on proposed model by carry out

testing To evaluate an efficient system for future study.

7Analysis of Forces acting on vehicles The amount of mechanical energy consumed by a vehicle when driving a

pre-specified driving pattern mainly depends on three effects: the aerodynamic friction losses the rolling friction losses the energy dissipated in the brakes. The elementary equation that describes the longitudinal dynamics of a road

vehicle has the following form

M(dv(t)/dt)= Ft(t) − (Fa(t) + Fr(t) + Fg(t))

The traction force Ft is the force generated by the prime mover minus the force that is used to accelerate the rotating parts inside the vehicle and minus all friction losses in the powertrain

8

Aerodynamic friction losses Usually, the aerodynamic resistance force Fa is

approximated by simplifying the vehicle to be a prismatic body with a frontal area Af . Fa(v) = ½.q.Af.Cd.v

Figure : Schematic representation of the forces acting on a vehicle in motion

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Rolling friction losses • The rolling friction is modeled as Fr = Cr.m.g.cos(a) rolling friction coefficient Cr depends vehicle speed v, tire pressure p, and road

surface conditions.

Uphill driving force The force induced by gravity when driving on a non-horizontal road is conservative and considerably influences the vehicle behavior. In this text this force will be modeled by the relationshipFg = m.g.sin(a)

10Analysis on vehicle

2001 Toyota Camry Specifications city mileage4: 0.103 Liter/km empty mass5: 1420 kg CD6: 0.29 Frontal Area: 2.42 m2

Coefficient of Rolling Resistance: 0.015

11Drivetrain Modelling in Simulink

12Fuel Consumption due to Rolling ResistanceLet's assume the car is carrying one passenger (70 kg) and a full tank of gas (40 kg).

Force of rolling resitance=(Coff of rolling resitance)(mass)(g) =(0.015)(1420+70+30)(9.81) =223N Work done against the rolling resistance=(force of rolling resistance)(distance) =223*1000 =223KJ Energy per liter= amt of joules/amt of lits Amt of lits = amt of joules/energy per lit = 892/32 = 0.028L Work done against air resitance=1/2*p*Acar *Cdv =1/2 (1.3*2.42*0.29*1000*14) =89.4KJ

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Efficiency=work output/fuel energy input Fuel energy input=Work output/Efficiency =89.4/25% =357.6KJ Energy per liter=amt of joules/amt of lits Amt of lits=amt of joules/energy per lit =357.4/32 =0.011L

Consumption due repeated acceleration= total camry fuel consumption-fuel consumed by rolling resistance –fuel consumed by air drag

=0.103-0.028-0.01 =0.064 L/KM

This tells us that repeated acceleration is responsible for about 0.064 / 0.103 = 62% of the city fuel economy.

For regenerative braking system, we could recover 70% of this energy, thereby saving (70%) (62%) = 43% of the total city fuel economy!

14

METHODOLOGYStudy of

Regenerative Braking System

Study of braking

component

CurrentScenario of

RBS

Literature review

Developing drive

schedule in Simulink

Analysing forces on vehicles

Fabrication of Prototype Testing Consult with

guideFinalize project

1 2 3 4 5

6 7 8 9 10

15Result

Development of drive cycle for vehicle in Simulink Potential of recovering 30% of energy (from calculations) Improved fuel economy by 7%

16References

1. http://auto.howstuffworks.com/auto-parts/brakes/brake-types/regenerative-braking.htm

2. http://www.hybridcars.com/components/regenerative-braking.html3. http://www.hybridcars.com/related-technologies/hydraulic-hybrids.html European Automobile manufacturing association, Economic report for

2007 (9/28/2008) Bosch Automotive Handbook – Rev. 7 – John Wiley & sons – (2007) Air Resource Board – Estimation of average vehicle average lifetime &

miles of travel - (Sept. 2004)