23291564 regenerative braking system

7/31/2019 23291564 Regenerative Braking System

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A

SEMINAR REPORT ON

REGENERATIVE BRAKING SYSTEM

SUBMITTED BY: GUIDED BY: -

ACKNOWLEDGEMENT

Thi s acknowl edgement i s a humbl e a t t emp t t o ea r nes t l y t hank a l l

t h o se w h o w e re d i re c t ly o r i n d ir e ct l y i n vo l v ed i n p r ep a ra t io n o f t h i s

seminar r epor t .

In par t i cu lar I am thankful to my guide Mr . Kalpesh D. Mania who

g u i d e m e i n m y s e m i n a r w o r k . I a m t h a n k f u l t o h i m f o r t a k i n g a c t i v e

p ar t in the p repa ra t i on o f my seminar r epor t . I t was imposs ib le to

p resen t th i s repor t wi th ou t h i s co- op era t ion and sugges t ion .


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L as t b ut n ot l ea st I w ou ld l ik e t o e xp re ss o ut d ee p s en se o f

g ra ti tu de t o a ll t he f ac ul ty m em be rs o f Me ch an ic al E ng in ee ri ng

Dep ar tmen t and a l s o my f r i ends who he l p me t o accomp l i sh wha t I have

s tar t ed for .

DEPARTMENT OF MECHANICAL ENGINEERING

THE SEMINAR REPORT ON :

REGENERATIVE BRAKING SYSTEM

PREPARED BY:

GUIDED BY:

EXAMINER H.O.D


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(1) ___________________

(2) ___________________

(3) ___________________

(4) ___________________

ABSTRACT

Regener at i ve Br ak i ng Sys t em i s t he way o f s l owing veh i c l e by us i ng t he

m o t or s a s b r a k es . I n st e ad o f t h e s u rp l u s e n er g y o f t h e v e h i cl e b e i n g

was t ed a s unwan t ed hea t , t he mot o r s ac t a s gene r a t o r s and r e t u r n s ome

of i t to the overhead wi res as e l ec t r i c i ty .

The veh i c l e i s p r i mar i l y p ower ed f r om t he e l ec t r i ca l ene r gy gene r a t ed

f r o m t he g e n e r at o r, w h i c h b u r n s g as o li n e . T h i s e n er g y i s s t o re d i n a

l a r ge ba t t e r y , and us ed by an e l ec t r i c mot o r t ha t p r ov i des mot i ve f o r ce

to the wheel s . The regenera t ive barking t aking place on the vehic le i s a

way t o ob t a i n mor e e f f i c i ency ; i n s t ead o f conver t i ng k i ne t i c ene r gy t o

t h e rm a l e n e rg y t h r ou g h f r ic t io n a l b r a ki n g, t h e v e h ic l e c a n c o n ve r t a

good f r ac t i on o f i t s k i ne t i c ene r gy back i n t o cha r ge i n t he ba t t e r y , u s i ng

the same p r inc ip le as an a l t e rna tor .


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LIST OF FIGURES

Fig . 1 Graphica l r ep resenta t ion of energy usage be tween two vehic le s.

Fig . 2 Mercury Hybr id Mar iner

Fig . 3 Regenera t ive Braking Sys tem Us ing Ni t inol Spr ing .


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CONTENTS

1. INTRODUCTION

2. NECESSITY OF THE SYSTEM

3. REGENRATIVE BRAKE

4. ELEMENTS OF THE SYSTEM

5. DESCRIPTION & OPERATION

6. RESULTS

7. CONCLUSION


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CHAPTER 1: INTRODUCTION

Brake: -

A br ake i s a mach i ne e l emen t and i t s p r i nc i p l e ob j ec t i s t o abs o r b

energy dur ing decelera t ion . In vehic le brakes are used to absorb k ine t i c

e n e r g y w h e r e a s i n h o i s t s o r e l e v a t o r s b r a k e s a r e a l s o u s e d t o a b s o r b

p oten t i a l ener gy . By conn ec t ing th e moving member to s t a t ion ary

f r am e , n o r ma l ly b r a k e c o n ve r ts k i n e t ic e n e r g y t o h e a t e n er g y . T h is

causes was tage of energy and a l so wear ing of f r i c t ional l in ing mater i a l .

Regenerat ive Braking System:-

R e ge n e ra t i ve B r ak i n g S y s t em i s t h e w a y o f s l ow i n g v e h i c le b y

us i ng t he mot or s a s b r akes . I ns t ead o f t he s u rp l us ene r gy o f t he veh i c l e

be ing was t ed as unwan ted hea t , the moto rs ac t as genera to r s an d re tu rn

some of i t t o the overhead wi res as e l ec t r i c i ty .

The veh i c l e i s p r i mar i l y p ower ed f r om t he e l ec t r i ca l ene r gy gene r a t edf r o m t he g e n e r at o r, w h i c h b u r n s g as o li n e . T h i s e n er g y i s s t o re d i n a

l a r ge ba t t e r y , and us ed by an e l ec t r i c mot o r t ha t p r ov i des mot i ve f o r ce

to the wheel s . The regenera t ive barking t aking place on the vehic le i s a

way t o ob t a i n mor e e f f i c i ency ; i n s t ead o f conver t i ng k i ne t i c ene r gy t o

t h e rm a l e n e rg y t h r ou g h f r ic t io n a l b r a ki n g, t h e v e h ic l e c a n c o n ve r t a


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good f r ac t i on o f i t s k i ne t i c ene r gy back i n t o cha r ge i n t he ba t t e r y , u s i ng

the same p r inc ip le as an a l t e rna tor .

T h e r e f o r e , i f y o u d r i v e l o n g d i s t a n c e w i t h o u t b r a k i n g , y o u l l b e

p ower ing the veh ic l e en t i r e ly f rom gaso l i ne . The regen era t ive braking

Regener at i ve Br ak i ng Sys t em comes i n t o i t s own when you r e d r i v i ng i n

the c i ty , and spending a good dea l of your t ime braking.

You wi l l s t i l l u s e mor e f ue l i n t he c i t y f o r each mi l e you d r i ve t han on

t h e h i gh w a y, t h ou g h . ( T he r mo d yn a m ic s t e ll s u s t h at a l l i n e ff i c ie n c y

c o m e s f r o m h e a t g e n e r a t i o n . F o r i n s t a n c e , w h e n y o u b r a k e , t h e b r a k e

p edal s hea t up and a quan t i ty of hea t , or energy , i s los t to the ou t s i de

wor ld . Fr i c t ion in the engine p roduces hea t in the same way.

H ea t e ne rg y, a ls o, h as h ig he r e nt ro py t ha n, s ay , e le ct ri c,

meaning that i t i s less ordered. )

Def in i t ion:

Br ak i ng me t hod i n wh i ch t he mechan i ca l ene r gy f r om t he l oad i s

conver ted in to e lec t r i c energy and regenera ted back in to the l ine i s

known as Regenera t ive Braking. The Motor opera tes as genera tor .

Regenerat ive Braking For Hybrid Vehicle:

I n m o s t e l e c t r i c a n d h y b r i d e l e c t r i c v e h i c l e s o n t h e r o a d t o d a y ,

t h i s i s a c c om p li s h ed b y o p e ra t i ng t h e t r ac t io n m o to r a s a g e n er a to r ,

p rov id i ng b raking to rque to the wheel s and rech argi ng the t rac t ion

ba t t e r i es . The ener gy p rovided by regenera t ive b rak in g can th en be used

for p ropul s ion or to power vehic le accessor ies .


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CHAPTER 2:NECESSITY OF THE SYSTEM

The r egener a t i ve b r ak i ng s ys t em de l i ve r s a number o f s i gn i f i can t

advan t ages ove r a ca r t ha t on ly has f r i c t ion b r akes . I n l ow- sp eed , s t op-

a n d -g o t r af f ic w h er e l i tt l e d e c el e ra t i on i s r e qu i r ed ; t h e r e ge n e ra t i ve

b rak in g sys tem can p rov ide the majo r i ty of the to ta l b raking force . Th i s

vas t l y i mp r oves f ue l economy wi t h a veh i c l e , and f u r t he r enhances t he

a t t r ac t i venes s o f veh i c l e s us i ng r egener a t i ve b r ak i ng f o r c i t y d r i v i ng .

At h igher speeds , too , r egenera t ive braking has been shown to cont r ibute

to improved fue l economy by a s much as 20%.

Cons i de r a heavy l oaded t r uck hav i ng ve r y f ew s t op s on t he r oad .

I t i s op e r at ed nea r max imum eng ine e f f i c i ency . The 80 % of the ene r gy

p roduced i s u t i l i zed to overcome the ro l l i ng and aerodynami c road

f o r ce s . T h e e n er g y w a st e d i n ap p ly i n g b r ak e is a bo u t 2 % . A l so i ts

b rake sp ec i f i c fue l con sumpt i on i s 5%.

Now con sider a veh ic le , wh ich i s opera ted in the main c i ty wher e

t r a f f i c i s a ma j o r p r ob lem he r e one has to ap p l y b r ake f r equen tl y . For

s u c h v e h i c l e s t h e w a s t a g e o f e n e r g y b y a p p l i c a t i o n o f b r a k e i s a b o u t

6 0% t o 6 5 %. A nd a ls o i t i s i n ef fi ci en t a s i t s b r ak e s p ec if ic f ue l

consumpt ion i s h igh .

HEAVY LOADED TRUCK CITY BUS

2.1 Graphical representation of energy usage between two vehicles.

Road 80%

Other

18%

Rake 65%

Road

26%

Brake 2% other 9%


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S ome of th e adv an tag es of r ege ne ra ti ve b raki ng o ve r

convent ional braking are as fo l lows:

Energy Conservat ion:

The f l ywhee l abs o r bs ene r gy when b r ak i ng v i a a c l u t ch s ys t em s l owi ngt he ca r down and sp eed i ng up t he whee l. To acce l er a t e , ano t he r c lu t ch

s ys t em connec ts t he f l ywheel t o t he d r i ve t r a i n , s p eed i ng up t he ca r and

s l owi ng down t he f l ywhee l . Ener gy i s t he r e fo r e cons e rved r a t he r than

w as ted a s h ea t a nd l igh t wh ic h i s wh at n orm al ly h app en s i n th e

contemporary shoe/d i sc sys tem.

A n e le c tr ic d ri v e t ra i n a ls o a ll ow s f o r r eg en e ra t iv e b r ea k in g w hi ch

increases Ef f i c iency Wear Reduction:

a n d r e d uc e s w e ar o n t h e v e h i c l e b r ak e s. I n r e g en e r at i v e r a ki n g , w h en

t h e m o t o r i s n o t r e c e i v i n g p o w e r f r o m t h e b a t t e r y p a c k , i t r e s i s t s t h e

t u rn i n g o f t h e w h e e ls , c a p t u ri n g s o m e o f t h e e n e r gy o f m o t i o n a s i f i t

w er e a g en e ra t or a n d r e tu r ni n g t h at e n er g y t o t h e b a t te ry p a ck . I n

m ec h an i ca l b r ak es ; l es s en i ng w ea r a n d e xt en d in g b ra k e l if e i s n o t

p oss ib le . Th i s reduces the use of use th e b rake .

Fuel Consumption:

T h e f u el c o n su m pt i on o f t h e c o n ve n t io n a l v e h ic l es a n d r e ge n e ra t i ve

b rak in g sys tem vehi c l es was evalua ted over a course o f var i ous f ixed

ur ban d r i v ing s chedu les . The r e su l t s a r e comp ar ed a s s hown i n fi gu r e .

Represent ing the s igni f i cant cos t saying to i t s owner , i t has been p roved

the regenera t ive braking i s very fue l -ef f i c i ent .

Braking i s not to ta l loss :

Conven t i ona l b r akes ap p l y f r i c t ion t o conver t a veh i c l e s k i ne t i c ene r gy

in to hea t . In energy t e rms , therefore , braking i s a to ta l loss : once hea t i s

genera ted , i t i s very d i f f i cu l t to r euse . The regenera t ive braking sys tem,

however , s lows a vehic le down in a d i f f erent way.


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CHAPTER 3 :REGENERATIVE BRAKING SYSTEM.

A regenerative brake is an apparatus, a device or system which allows a vehicle to recapture

and store part of the kinetic energy that would otherwise be 'lost' to heat whenbraking.

The IMA operating principle

Honda's patented IMA concept i s qui te s imple - use an ef f icient Ot to

engine supplemented by an elect r ic motor when addi t ional power i s

needed. Also refer red to as a ' hybr id ' sys tem because i t uses two power sources , the IMA concept al lows the Civic Hybr id to use a smal ler

gasol ine engine wi thout any s ignif icant loss in performance.

This sys tem is especial ly ef fect ive due to the fact that accelerat ion

requi res a s igni f i cant ly h igher power than needed for c ru i s ing on a l evelroad (where vehicles spend most of thei r t ime) . An engine more powerful

than needed has to work under low load mos t of the t ime, condi t ion where

i t s e f f i c i ency i s lower than under h igh loads , thus worsening the vehic le ' sfue l economy. .
http://en.wikipedia.org/wiki/Vehiclehttp://en.wikipedia.org/wiki/Kinetic_energyhttp://en.wikipedia.org/wiki/Heathttp://en.wikipedia.org/wiki/Brakehttp://en.wikipedia.org/wiki/Vehiclehttp://en.wikipedia.org/wiki/Kinetic_energyhttp://en.wikipedia.org/wiki/Heathttp://en.wikipedia.org/wiki/Brake


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The elect r ic motor-generator pos i t ioned between the engine and

t ransmission ass i s t s the engine when accelera t ing and recovers energy to

s tore in ba t t e r i es when braking or decelera t ing ( regenera t ive braking) ,a l lowing i t to opera te independent ly wi thout the need for a gr id power

supply.

When the Civic Hybr id i s coas t ing or i t s brakes are appl ied, i t s elect r ic

motor becomes a generator , conver t ing forward momentum (kinet icenergy) in to e lec t r i ca l energy, ins tead of was t ing i t as hea t dur ing

convent ional braking. Energy i s s tored in a ba t t e ry pack loca ted behind

the rear sea t in the t runk. I f the s t a t e of charge of the ba t t e r i es i s low,the motor -genera tor wi l l a l so r echarge them whi le the Civic Hybr id i s

cru i s ing .


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CHAPTER 4: ELEMENTS OF THE SYSTEM

T h er e a re t hr ee b a si c e le me n t r eq u ir ed w hi ch a re n e ce ss ar y f o r t he

working of r egenera t ive braking sys tem, these are :

1 .Energy Storage Uni t (ESU):

The ESU per forms two p r imary funct ions

1 .TO recover & s tore braking energy

2. TO absorb excess engine energy dur ing l ight load opera t ion

The se lec t ion cr i t e r i a for an ef fec t ive energy s torage inc ludes

1 . High speci f i c energy s torage dens i ty

2 . High energy t r ans fer r a te

3 . Smal l space requi rement

The ene r gy r ecap t u r ed by r egener a t i ve b r ak i ng mi gh t be s t o r ed i n one o f

t h r ee dev i ces : an e l ec t r ochemi ca l ba t t e r y , a f l ywhee l , i n a r egener a t i ve

fuel ce l l .

Regen and Batteries :

W i t h t h i s s ys t em, t he e l ec t r i c mot o r o f a ca r becomes a gene r a t o r when

t h e b r a k e p e d a l i s a p p l i e d . T h e k i n e t i c e n e r g y o f t h e c a r i s u s e d t o

gener a t e e l ec t r i ci t y t ha t i s t hen us ed t o r echa r ge t he ba t t e r i e s . W i t h t h i s

s ys t em, t r ad i t i ona l f r i c t i on b r akes mus t a l s o be us ed t o ens ur e t ha t t he

car s lows down as much as necessary . Thus , not a l l of the k ine t i c energy

of t he ca r can be ha r nes sed f o r t he ba t t er i e s becaus e s ome o f i t i s " l os t "

t o w as te h e at . S om e e n er gy i s a ls o l os t t o r es is ta n ce a s t he e n er gy

t ra v el s f ro m t h e w he el a n d a x le , t h ro u gh t h e d ri v et ra in a n d e le c tr i c

m o to r, a n d i n to t he b a tt er y . F or e xa mp le , t he T oy o ta P ri us c an o n lyrecap ture about 30% of the vehic les k ine t i c energy.

The Honda I ns i gh t i s ano t he r veh i c l e i n add i t i on t o t he P r i us t ha t i s on

t he mar ke t and cu r r en t ly us es r egenera t i ve b r ak i ng . I n t he I ns i gh t t he r e

a r e t wo dece l e r a t i on modes : W hen t he t h r o t t l e i s engaged , bu t t he b r ake


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p edal i s not , th e veh ic le s lows down gradua l ly , and the ba t t e ry r ece ives

a par t i a l charge .

W hen t he b r ake p eda l i s dep r es s ed , t he ba t t e r y r ece i ves a h i ghe r

charge , which s lows the vehic le down fas ter . The fur ther the brake

peda l i s dep ressed , the more th e conven t i on al f r i c t i on brakes are

employed.

In the Ins ight , the motor /genera tor p roduces AC, which i s conver ted in to

D C , w h i c h i s t h e n u s e d t o c h a r g e t h e B a t t e r y M o d u l e . T h e I n s i g h t , a s

we l l a s a l l o t he r r egener a t i ve s ys t ems , mus t have an e l ec t r i c con t r o l l e r

t ha t r egu l a t e s how much cha r ge t he ba t t e r y r ece i ves and how much t he

f r i c t ion brakes are used .

Regen and Flywheels :

In th i s sys tem, the t r ans la t ional energy of the vehic le i s t r ans fer red in to

r o ta t i on a l e n e r g y i n t h e f l y w h ee l , w h i c h s t or e s t h e e n e rg y u n t il i t i s

n ee de d t o a cc el er at e t he v eh ic le . Th e b en ef it of u sin g f ly wh eel

t echno l ogy i s t ha t mor e o f t he f o r war d i ne r t i a l ene r gy o f t he ca r can be

c a p t u r e d t h a n i n b a t t e r i e s , b e c a u s e t h e f l y w h e e l c a n b e e n g a g e d e v e n

dur i ng r e l a t i vel y s hor t i n t e r va l s o f b r ak i ng and acce l e r a ti on . I n t he cas e

of ba t t e r i e s , t hey a r e no t ab l e t o accep t cha r ge a t t hes e r ap i d i n t e r va l s ,

and t hus mor e ene r gy i s l o s t t o f r i c t i on . Ano t he r advan t age o f f l ywhee l

t echno l ogy i s t ha t t he add i t i ona l p ower s up p l i ed by t he f l ywhee l du r i ng

a c c el e ra t i on s u bs t an t i al l y s u pp l em e n ts t h e p o we r o u tp u t o f t h e s m a ll

engine tha t hybr id vehic les a re equipped wi th .


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2. Continuously Variable Transmission (CVT):

T h e e n e r g y s t o r a g e u n i t r e q u i r e s a t r a n s m i s s i o n t h a t c a n h a n d l e

t o r q u e a n d s p e e d d e m a n d s i n a s t e e p l e s m a n n e r a n d s m o o t h l y c o n t r o l

e n er gy f lo w t o a n d f r o m t he v eh i cl e w h ee ls . F o r t he f l y wh e el t h e

c on ti nu ou sl y v ar ia bl e t ra ns mi ss io n a nd v eh ic le b ec au se f ly wh ee l

ro ta t ional speed increases when vehic le speed decreases and v ice ver sa .

F ly w he el c an w o rk w el l w it h e it h er m ec h an i ca l o r h y dr os ta ti c

cont inuous ly var i able t r ansmiss ion .

3. Control System :

An ON- OFF eng i ne con tr o l s ys tem i s us ed . Tha t means t ha t t he

e n gi n e i s ON u n ti l t h e e n e rg y s to r ag e u n it h a s b e e n r ea ch e d t h e

d e si re d c h ar ge c a pa c it y a n d t h en i s d ec o up le d a n d s to pp ed u n ti l t h e

energy s torage uni t charge fa l l be low i t s minimum requi rement .


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CHAPTER5: DESCRIPTION & OPERATION

How regenerat ive braking system works?

R eg en er at iv e ( or Dy na mi c B ra ki ng ) o cc ur s w he n th e v eh ic le i s i n

m o ti on , s u c h a s c o a st in g , t r av e li n g d o wn h il l o r b ra ki n g. A nd t h e

acce l e r a to r p eda l i s no t be ing dep r ess ed . Dur i ng Regen t , t he mot o r

becomes a genera to r an d sends energy back to the ba t te r i es .

I t i s e x p l a i n e d a s f o l l o w s , b e c a u s e t h e w h e e l s o f a d e c e l e r a t i n g

veh i c l e a r e s t i l l mov i ng f o r war d , t hey can be made t o t u r n t he e l ec t r i c

mot o r , wh i ch t hen f eeds ene rgy t o t he ba t t e r ie s f o r s t o r age . The s ys t em

becomes , in ef fec t , a genera to r , wh ich p rovides brak in g force wh i le i t

c o n v er t s t h e v e h ic l e s k i n et i c e n er g y i n t o a r e us a b le f o rm - e l e ct r i ca l

energy.

W h en t h e a c c el e ra t o r p e da l i s r e le a s ed , t h e a b se n c e o f p r es s u re

t r i gge rs a r e s p onse f rom t he Ener gy S t o r age Uni t ( ESU) . Regenera t i ve

b rak in g begi ns , and the ba t t er i es a re r e-charged by the motor , wh ich i s

t u r ned by t he whee l s . I n t h i s cas e , t he f r i c t i on b r akes a r e no t engaged .

I f m or e v ig or ou s d ec el er at io n i s r eq ui re d, a nd t he b ra ke p ed al i s

d e p re s se d , t h i s e ng a g es b o t h s e ts o f b r a k e s. H o we v er , t o m a x i mi z e

ener gy e f f i c i ency, i t i s advan t ageous t o ap p l y t he r egenera t i ve b r ake a ss uch a s p os s i b l e i t t he r e f o r e t ends t o do mor e o f i t s t o t a l wor k i n t he

f i r s t par t of the braking mot ion .

There are two decelera t ion modes :

1 . F oo t of f th ro tt le b ut n ot o n b ra ke pe da l i n th is m od e, th e

cha r ge / as s i s t gauge wi l l s how p a r t i al cha r ge , and t he veh i c l e w i l l s l ow

down gradual ly .


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2 . Foo t on b r ake p eda l - I n t h i s mode , a h i ghe r amoun t o f r egener a t i on

wi l l be a ll owed , and the veh i c l e wi l l s l ow mor e r api d l y . Dur i ng li gh t

b rake peda l app l i ca t i on , on ly the IMA motor / /gen er a tor i s s lowi ng th e

c a r . W i th h e a vi e r b r a ke p e d a l a p p li c a ti o n , t h e c o n v en t i on a l f r i ct i on

b rakes a l so come in to p lay . When decel er a t ing , r egenera t ion wi l l

con t i nue u8n ti l eng i ne s p eed f a l l s t o abou t 100 0 r p m. At t h i s p o in t , t he

dr iver wi l l typ ica l ly sh i f t in to neut ra l .


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EXAMPLE

Mercury Hybrid Mariner

1 . M e rc u ry Ma r ine r H y br id

Product ion Pul l ahead: Product ion begins a year ahead

of schedule

Growing the Mercury Brand: New model s and goal s

Dis t inc t ive Des ign: Mar iner f ea tures c lean l ines , carefu lcraf t smanship

Power Play: Ful l -hybr id gasol ine and e lec t r i c power t ra in

Dynamic Chass i s : Nimble handl ing and a smooth , quie t r ide

Dis t ingui shed Safe ty : Ful l a r ray of safe ty f ea tures

Green Miss ion: Ford Motor Company ' s s t r a tegy for sus ta inabi l i tyin vehic les

The Mercury Mar iner Hybr id of fer s a uniquely sa t i s fy ing t r anspor ta t ion

choice for an ever - increas ing segment of the popula t ion concerned aboutthe envi ronment . I t ' s a s ty l i sh , upsca le spor t -u t i l i ty vehic le wi th n imble

handl ing and impress ive per formance , as wel l as ample cargo and towingcapaci ty . In addi t ion , i t ' s an envi ronmenta l ly conscious SUV wi th

remarkable fue l economy an es t imated 33 mi les per ga l lon (mpg) c i ty ,29 mpg highway and i s expected to meet the c leanes t emiss ions r a t ing

achievable by a foss i l - fue l vehic le (Cal i forn ia ' s Advanced Technology

Par t i a l Zero Emiss ions Vehic le s t andard) .
http://63.74.120.214/adclick.php?n=abc876dfhttp://www.americancarfans.com/news.cfm/newsid/2050211.012/pageview/photo/photo/1/page/1/lang/eng/mercury/1.html


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Engineer s p laced the addi t ional hybr id power t ra in component s low and

to the r ear , to lower the center of gravi ty and improve the convent ional

Mar iner ' s f ront - rear weight d i s t r ibut ion .

The rack-and-p in ion s t eer ing i s e l ec t r i ca l ly ass i s t ed , r a ther than us ing

the t r adi t ional hydraul i c s t eer ing pump for cons i s t ent s t eer ing ef for t sand cont ro l whether the gasol ine engine i s s topped or running.

Regenera t ive braking uses the t r ac t ion motor to ass i s t the four -wheeld i sc brakes in s lowing Mar iner Hybr id whi le s imul taneous ly genera t ing

elec t r i c i ty for charging the ba t t e ry .

Regenerat ive braking of Toyota Prius:

Toyot a r ea l i zed t ha t one way t o ach i eve l onger veh i c l e r ange was

t o cons e r ve and r eus e s ome o f t he ene r gy t ha t a veh i c l e no r ma l l y l os es

as hea t caus ed by b r ak i ng f ri c t i on . Th i s i dea l ed eng i nee rs t o ap p l y the

p r inc ip les of r egenera t iv e b rak in g.

I n a ll T oy ot a v eh ic le s th at f ea tu re t he r eg en er at iv e b ra ki ng

s y st em , t h e r eg en e ra ti v e b r ak e i s o n ly r es po n si b le f o r a p ar t o f t he

d e c el e r at i o n n e c es s ar y t o s t o p t h e v e h i cl e . I n a n E V , t h i s f r a ct i o n i s

d e te rm i ne d b y t he v eh i cl e s s p e ed w he n b r a ki n g i s i n i ti a te d. T he

remaining braking force i s provided by the vehic le s f ri c t ion brakes . To

maxi mi ze f ue l economy, o f cour s e , t he r egener a t i ve b r ak i ng s ys t em i s

made to do as much of the brakin g work as poss ib le .


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Component Used in Toyota Prius for Regenerat ive Braking System:

Brake Peda l :

I t i s used to app ly braking force by the dr iv er .

Hyd ra ul i c Boo s t er Uni t :

I t i s comp os ed o f t he mas t er cy l i nde r and t he r egu l a t o r , r e s p onds i n t wo

s t ep s . F i r s t i t s i gna l s e l ec t r on i cal l y t o t he b r ake ECU t ha t b r ak i ng f o r ce

has been demanded . Nex t , t he mas t e r cy l i nde r exe r t s hydr au l i c p res s u r e

on t he p eda l s t r oke s i mul a to r , and t he r egu l a t o r f eeds hydr au l i c f l u i d t o

the hydraul i c p ressure cont ro l uni t .

Brake ECU:

The b r ake ECU s ens es t he b r ak i ng demand and s ends a f r ac t i on o f t h i s

demand to the THSECU for r egenera t ive braking.

I t a ls o c al cu l at es t he f or ce n e ce ss ar y t o f u lf il l r em ai n in g b r ak in g

d e m a n d a n d i n s t r u c t t h e h y d r a u l i c p r e s s u r e c o n t r o l u n i t t o p a s s o n a

cor responding amount of hydraul i c f lu id

Pedal S t roke Si mula t or :

I t a b s o r b s a n a m o u n t o f h y d r a u l i c p r e s s u r e f r o m m a s t e r c y l i n d e r t h a t

co r r es p onds t o t he amoun t o f b r ak i ng f o r ce ap p l i ed by t he r egener a t i veb rak in g sys t em.

As hydraul i c p ressure i s f ed back to the pedal , the pedal , the pedal

s t roke s imula tor f eeds back to the mas ter cyl inder .

THS (Toyo ta Hybr id Sys tem) ECU:

I t i n du c es r eg en e ra t iv e b ra k in g, a n d r et ur n s a s i gn a l t ha t i n di c at es

b rak in g fo rce ou tput back to the brake ECU.

Hyd ra ul i c Pressure Cont ro l Uni t :

I t p a s s e s o n a c o r r e s p o n d i n g a m o u n t o f h y d r a u l i c f l u i d t o a f o u r w a y

cyl inder .


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CHAPTER 6: RESULT

Regenera t ive braking t echnology i s one more pos i t ive s t ep forward

i n Toyo t a s ques t t o r ea l i ze t he u l t i ma t e ecoca r . By wor k i ng i n conce r t

w i t h p r ev i ous l y deve l op ed e l ec t r i c mot o r t echno l ogi es , i t s ap p l ica t i on

h e lp s T oy o ta s e le c tr ic v eh i cl es a n d h y br id v eh i cl es ( i nc lu di n g t h e

r ecen t l y r e l eas ed p r i us ) t o ach i eve ex t ended r anges and t o be f r i end l i e r

t o t h e e nv ir on me nt t ha n e v er b ef or e. A t t h e s a me t im e, t hi s n e w

t e c hn o l og y r e ma i n s u n o bt r us i v el y i n t h e b a c kg r ou n d ; d r i ve r s b e n ef i t

f r o m r e g e n er a t iv e b r ak i n g w h i l e e n j oy i n g t h e s a me f i rm b r a ki n g f e el

found in convent ional ly equipped vehic les .

7.1 Regenerative braking system using Nitinol Spring

Wheel

Rotating Device.

Shafts.

Gearbox Clutch Spring

Wheel A

Rotating Device BShafts C.D.

Gearbox EClutch G

Spring - H


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A hydraulic regenerative braking system improves the fuel economyof Ford's F-350 Tonka 25-35% during stop-and-go driving. The

system provides power during initial acceleration when demand

peaks.

The HLA sys tem cons i s t s of a r ever s ib le hydraul i c p ump/motor f rom

Eaton ' s F lu id Power Group (Eden Pra i r i e , MN) coup led to the dr ive shaf t

through a c lu tch an d two accumula tor s . As the dr iver s t eps on the brak e ,the pump/motor forces hydraul i c f lu id out of a low-pressure ac cumula tor

and in to a h igh-p ressure accumula tor , increas ing the p ressure of

n i t rogen gas s tored there to 5 ,000 ps i .

Dur ing accelera t ion , the HLA sys tem swi tches f rom the pump mode tothe motor mode, the n i t rogen gas forces the hydraul i c f lu id back in to the

low-pressure accumula tor , and th e pump/motor app l i es torque to the

dr iveshaf t through the c lu tch . I f quick accelera t ion i s r equi red , the F-350 ' s d iese l engine works wi th the HLA sys tem


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The hydraul i c launch ass i s t s ys tem in the F-350 Tonka funct ions as asecondary source o f energy dur i ng peak power demand . I t cons i s t s o f a

low-pressure accumulator in b lue , and a h igh-pressure accumulator in

red . The sys tem captures energy normal ly d i s s ipated as heat dur ing breaking , s tores i t , and uses i t l a ter dur ing per iods o f peak power

demand .

Eighty percent of the in i t i a l k ine t i c energy i s r e turned to the vehic le .

"The sys tem s tores approximate ly 380 kJ of energy," says Brad

Bohlmann, a mechanica l engineer and bus iness development coordina tor in Advanced Technology a t Eaton ' s F lu id Power Group . "Wi th tha t much

energy, we can accelera te a 10 ,000- lb vehic le f rom a dead s top to

be tween 2 5 and 30 mi les per hour wi th no a ss i s t an ce f rom the vehi c le ' scombus t ion engine ."

"Ford th inks tha t both e lec t r i c and hydraul i c r egenera t ive sys tems have

a fu ture ," says John Brevick , a Ford mechanica l engineer working on the

HLA sys tem. "But for heavy vehic les l ik e our 10 ,000- lb F-350 t rucks ,hydraul i cs a re be t t e r a t cap tur ing los t energy than e lec t r i c sys tems ."

Eaton ' s Bohlmann exp la ins tha t the r ea l advantage of hydraul i cs i s in i t s

p ower dens i ty . " Hydraul i c s i s cap ab le of t r an sfer r ing energy very

quickly ," says Bohlmann. "The ra te of energy t r ans fer i s in a hybr ide lec t r i c sys tem of a s imi lar s i ze i s much lower ."

Bohlmann adds tha t the speci f i c vocat ion or dr iv ing cycle of the vehic le

determines whether a hybr id hydraul i c or hybr id e lec t r i c sys tem i s bes t


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sui t ed for the vehic le . "Think of hydraul i cs as a sp r in ter , p rovid ing fas t

bu rs t s of power , " he says . "An el ec t r i c h ybr id i s more l ike a mara thon

runner ."

"The chal l enge now i s to make use of the r egenera t ive braking sys tem

seamless to the cus tomer ," says Ford ' s Brevick . "We s t i l l have room for improvements and fee l the HLA sys tem has a lo t of potent i a l . "

As for the fu ture , Ford , Eaton, and the U.S. Envi ronmenta l Protec t ionAgency (EPA) are jo in t ly conduct ing research on hydraul i c hybr id

vehic les , inc luding in terna l combus t ion engines tha t would p roduce

hydraul i c p ressure to dr ive the vehic le . Eaton s igned both a t echnologyl i cense agreement and a coopera t ive r esearch and development

agreement wi th the EPA for the development of fu ture genera t ion

sys tems .

Inert ia , Force and MassEveryth ing has iner t i a ; i f i t h as a mass , i t has iner t i a . A hybr id r ec la ims

energy through the fundamenta l s of phys ics . Do you remember any h igh

school or col l ege phys ics?

You app ly a force to move an objec t . Th e equat ion for th i s i s :

F=maF being the force , m being the mass and

a be ing the accelera t ion

The fas ter you want an objec t to acce lera te , the more force you have toapp ly .

Let s jus t look a t the e lec t r i c motor for now. Energy f rom the ba t t e ry

(Wat t s ) i s app l i ed to the coi l windings in the motor . These win dings

then p roduce a magnet i c force on the ro tor of the motor , which p roduc estorque on the output shaf t . Thi s torque i s then app l i ed to the wheel s of

the car v ia a coup l ing of gear s and shaf t s . When the wheel turns , i t

app l i es a force to the ground, which due to f r i c t ion be tween the whe el

and the ground causes the vehic le to move a long the sur face . Thi s i s l ikei f you were in a boat a t a dock, and you grabbed the d ock and pushed

wi th your a rm. The force you are genera t ing i s moving the boat r e l a t iveto the loca t ion of the d ock. The more force you app ly , the f as t you ge tthe boat to move.

Fric t ion in Hybrids

There i s f r i c t ion everywhere in the hybr id sys tem. There i s e l ec t r i ca l

f r i c t ion be tween the a toms and e lec t rons moving in the wi res be tweenthe ba t t e ry and the motor and through the motor i t se l f . There i s


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magnet i c f r i c t ion in the meta l l aminat ions tha t make up the magnet i c

c i rcui t of the motor , as wel l as in the magn et s aga in on the a tomic l evel .

Then, there i s mechanica l f r i c t ion be tween every moving par t , such asthe bear ings , sea l s , gear s , cha ins and so on . The by-p roduct of f r i c t ion

i s hea t . Take your h ands rub them together and your pa lms get warm.

The fas ter you do i t , t he f as ter they hea t up . Also , the harder they arep ressed togeth er , the fa s ter th ey wi l l h ea t . Fr i c t ion is energy los t to

heat . When a l l of these losses a re a dded up , tha t i s what de termines the

ef f i c i ency of the vehic le .

Fric t ional Losses in Convent ional Cars

A s tandard car genera tes torque to move the wheel s to dr ive the vehic le

down the road . Dur ing th i s t ime, i t i s genera t ing f r i c t ion and losses .

When you app ly s t andard brakes , i t i s jus t another f r i c t ion device tha thas specia l ly des igned mater i a l to handle the hea t f rom f r i c t ion , which

i s app l i ed to the drums and ro tor s tha t s top the wheel f rom turnin g . The

f r i c t ion be tween the wheel and the ground s tops the vehic le . Thi ss tandard vehic le has f r i c t ional losses to move the vehic leand uses the

fundamenta l behind f r i c t ional losses to s top the vehic le . So i t s a lose-

lose s i tua t ion .

Transferring Torque Back to the Motor

This iner t i a i s the fundamenta l p roper ty of phy s ics tha t i s used to

rec la im energy f rom the vehic le . Ins tead of us ing 100% of the

foundat ion brakes of the vehic le , which are the f r i c t ion brakes , we now

let the l inkages back to the motor such as the dr ive shaf t s , cha ins , andgears t r ans fer the torque f rom the wh eel s back in to the motor shaf t . One

of the unique th ings about mos t e l ec t r i c motors i s tha t e l ec t r i ca l energycan be t r ans fer red in to mechanica l energy and a l so mechanica l energycan be t r ans fer red back in to e lec t r i ca l energy. In both cases , th i s can be

done very ef f i c i ent ly .

Thus , through the t echnology of the motor and motor cont ro l l e r , the

force a t the wheel s becomes torque on the e lec t r i c motor shaf t . Themagnet s on the shaf t of the motor ( ca l l ed the ro torthe moving par t of

the motor ) move pas t the e lec t r i c coi l s on th e s t a tor ( the s t a t ionary par t

of the motor ) pass ing the magnet i c f i e lds of th e magnet s through thecoi l s p roducing e lec t r i c i ty . Thi s e l ec t r i c i ty becomes e lec t r i ca l energy,

which i s pumped back to the ba t t e ry . Thi s , in turn , charges the hybr id

ba t t e ry p ack. Th i s i s where the commen t regen era t i on o r rec la i min genergy comes f rom.

That i s the bas ics of how regenera t ion works . How much energy you can

rec la im depends on a lo t of f ac tor s . There are d i f f erent r egenera t ion

theor ies and des igns , which fa l l in to two groups : one be ing ca l l edp ara l l el regen and the o ther ca l l ed ser i es r egen , whi ch are d i f f eren t f rom


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the para l l e l and ser i es hybr ids . These regen groups s t r i c t ly a re des ign

topologies for braking sys tems . I t a l so mat ter s h ow many wheel s you are

us ing to r ec la im energy. Mos t veh ic les to da te a re f ront wheel dr ive soyou can only rec la im energy f rom the f ront wheel s . The back wheel s

s t i l l was te energy to s t andard f r i c t ion brakes unless they are somehow

connected back to the e lec t r i c motor . The o ther f ac tor i s ba t t e ry s t a t e of charge and how hard can you dr ive tha t energy back in to the ba t t e ry .


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CHA PT ER 7: CONCLUSION

Theor e t i ca l i nves t i ga t i ons o f a r egener a t i ve b r ak i ng s ys t em s how abou t

25% saving in fue l consumpt ion .

T he l ow er o pe ra ti ng a nd e nv ir on me nt c os ts o f a v eh ic le w it h

r e ge n er a ti v e b ra ki n g s ys te m s ho u ld m ak e i t m o re a tt ra c ti v e t ha n a

conven t i ona l one . The t r ad i ti ona l cos t o f the s ys t em cou l d be r ecover ed

in the f ew year s only .

The exhaus t emi s s i on o f veh i c l e us i ng t he r egenera t i ve b r ak i ng concep t

w o u ld b e m u ch l e ss t h an e q u iv a l en t c o n ve n ti o n al v e h ic l e s a s l e ss f u el

are used for consumpt ion .

Thes e s ys t ems a r e p a r t i cu l a r l y s u i t ab l e i n deve l op i ng coun t r i e s s uch a s

I nd i a wher e bus es a r e t he p r e f e r r ed means o f t r ans p or t a t i on wi t h i n t he

c i t i es .


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BIBLIOGRAPHY

1) General Motors Website ( www.gm.com ) .

2 ) w ww .s ae .o rg

3 ) ww w. go og le .c om
http://www.gm.com/http://www.gm.com/

23291564 regenerative braking system

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