DEGREE engineering college, CHANDIPADAR ,(Berhampur) Seminar report on

Regenerative Braking System

MECHANICAL ENGINEERING

Submitted by Abhishek kumar mishra Regd.No.-0801220287 ( 8th SEM.)

BONAFIDE CERTIFICATE
This is to certify that the student ABHISHEK KUMAR MISHRA of Mechanical Engineering have undergone the live seminar on Regenerative Braking System and has prepared this seminar report by virtue of his diligence adherence and advice. He has successfully completed every aspect of this seminar with a lot of sincerity and devotion during the seminar was very much appreciating. We wish him all success for bright future.

Er.Ritanjali Panda (Seminar guide)

Dr. J.K.Sahu (HOD E&TC)

acknowledgement
I am grateful to my seminar guide ER. RITANJALI PANDA for his able guidance and constructive criticism. I also owe my gratitude to Dr. J.K.SAHU and all the faculty members of our branch for their kind cooperation during the seminar framing period. Last but not the least I am extremely thankful to my friends for their support during the preparation of seminar.

Signature of Student

CONTENTS
ABSTRACT INTRODUCTION NECCESITY OF REGEN. BRAKING HOW IT WORKS REGEN. IN RAIL VEHICLES REGEN. IN ROAD VEHICLES BENEFITS AND DOWNSIDES OF

REGEN. BRAKING
CONCLUSION

ABSTRACT
R e g e n e r a t i ve Braking Sy s t e m is the wa y of s l o wi n g ve h i c l e b y u si n g t h e m o t o r s a s b r a k e s. I n st e a d of the surplus energy of the vehicle

b e i n g wa st e d a s u n wa n t e d h e a t , t h e m o t o r s a c t as generators and return so m e of it to the

o ve r h e a d wi r e s a s e l e c t r i c i t y. The ve h i c l e is primarily powered from the

electrical energy generated from the generator, which burns gasoline. This energy is stored in a

l a r g e b a t t e r y, a n d u s e d b y a n e l e c t r i c m o t o r t h a t p r o vi d e s motive force to the w h e e l s. Th e

r e g e n e r a t i ve b a r k i n g t a k i n g p l a c e o n t h e v e h i c l e i s a wa y t o o b t a i n m o r e e f f i c i e n c y ; i n s t e a d o f c o n ve r t i n g through c o n ve r t kinetic energy braking, of to thermal energy c an

frictional a good

the its

vehicle kinetic

fraction

energy

b a c k i n t o c h a r g e i n t h e b a t t e r y , u s i n g t h e sa m e principle as an alternator.

INTRODUCTION
Brake:A brake is a is machine to element energy are in and its

principle

object In

absorb

during used to or

deceleration. absorb kinetic

vehicle

brakes

energy are By

whereas also

h o i st s to the

e l e va t o r s potential member

brakes e n e r g y. to

u se d

a b so r b moving brake This

connecting frame,

stationary

normally

c o n ve r t s k i n e t i c e n e r g y t o h e a t e n e r g y.

c a u se s w a st a g e o f e n e r g y a n d a l so w e a r i n g o f frictional lining material .

Regenerative Braking System:R e g e n e r a t i ve B r a k i n g Sy st e m i s t h e w a y o f s l o wi n g ve h i c l e b y u si n g t h e m o t o r s a s b r a k e s. I n st e a d of the surplus energy of the vehicle

b e i n g wa st e d a s u n wa n t e d h e a t , t h e m o t o r s a c t

as

generators

and

return

so m e

of

it

to

the

o ve r h e a d wi r e s a s e l e c t r i c i t y. The ve h i c l e is primarily powered from the

electrical energy generated from the generator, which burns gasoline. This energy is stored in a

l a r g e b a t t e r y, a n d u s e d b y a n e l e c t r i c m o t o r t h a t p r o vi d e s motive force to the w h e e l s. Th e

r e g e n e r a t i ve b r a k i n g t a k i n g p l a c e o n t h e v e h i c l e i s a wa y t o o b t a i n m o r e e f f i c i e n c y ; i n s t e a d o f c o n ve r t i n g through c o n ve r t kinetic energy braking, to thermal energy can

frictional a good

the its

vehicle kinetic

fraction of

energy

b a c k i n t o c h a r g e i n t h e b a t t e r y , u s i n g t h e sa m e principle as an alternator. T h e r e f o r e , i f y o u d r i ve l o n g d i s t a n c e wi t h o u t b r a k i n g , yo u l l b e p o we r i n g t h e ve h i c l e e n t i r e l y from gasoline. R e g e n e r a t i ve B r a k i n g S y st e m c o m e s i n t o i t s o wn w h e n y o u r e d r i vi n g i n t h e c i t y, a n d sp e n d i n g a good deal of your time braking. Y o u wi l l st i l l u s e m o r e fu e l i n t h e c i t y f o r e a c h mile yo u drive than on the highway, though.

( Th e r m o d y n a m i c s t e l l s u s t h a t a l l i n e f f i c i e 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 st a n c e , w h e n you brake, the brake pedals heat up and a

q u a n t i t y o f h e a t , o r e n e r g y , i s l o st t o t h e o u t si d e world. Friction in the engine produces heat in

t h e sa m e wa y . H e a t e n e r g y, a l s o , h a s h i g h e r e n t r o p y t h a n , s a y, e l e c t r i c , m e a n i n g t h a t i t i s l e ss o r d e r e d . )

Definition:
B r a k i n g m e t h o d i n wh i c h t h e m e c h a n i c a l e n e r g y f r o m t h e l o a d i s c o n ve r t e d i n t o e l e c t r i c e n e r g y a n d r e g e n e r a t e d b a c k i n t o t h e l i n e i s k n o wn a s R e g e n e r a t i ve B r a k i n g . generator. Th e Mo t o r o p e r a t e s a s

NECESSITY OF THE SYSTEM

The r e g e n e r a t i ve braking s y st e m d e l i ve r s a n u m b e r o f si g n i f i c a n t a d va n t a g e s o v e r a c a r t h a t only has friction brakes. I n l o w - sp e e d , s t o p - a n d -

g o t r a f f i c wh e r e l i t t l e d e c e l e r a t i o n i s r e q u i r e d ; the regenerative braking system can provide the

majority of the total braking force. improves fuel economy with a

T h i s va st l y ve h i c l e , and

further enhances the attractiveness of vehicles u si n g r e g e n e r a t i ve b r a k i n g f o r c i t y d r i vi n g . higher been sp e e d s, s h o wn to too, r e g e n e r a t i ve to braking At has f uel

contribute

i m p r o ve d

economy by as much as 20%. C o n si d e r a h e a v y l o a d e d t r u c k h a vi n g ve r y few st o p s on the road. It is operated 80% of near the the

maximum energy

engine

e f f i c i e n c y. is utilized

The to

produced

o ve r c o m e

r o l l i n g a n d a e r o d yn a m i c r o a d f o r c e s.

The energy Also its

w a st e d i n a p p l y i n g b r a k e i s a b o u t 2 % . b r a k e sp e c i f i c f u e l c o n su m p t i o n i s 5 % .

Now consider a vehicle, which is operated in the main city where traffic is a major problem h e r e o n e h a s t o a p p l y b r a k e f r e q u e n t l y. For such

v e h i c l e s t h e w a st 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 brake is about 60% to 65%. And also it is

i n e f f i c i e n t a s i t s b r a k e sp e c i f i c f u e l c o n su m p t i o n is high.

HOW IT WORKS
R e g e n e r a t i ve ( o r D yn a m i c B r a k i n g ) o c c u r s w h e n the vehicle is in motion, or such as coasting, And the

t r a ve l i n g

d o wn h i l l

brak ing.

a c c e l e r a t o r p e d a l i s n o t b e i n g d e p r e s se d . D u r i n g Regent, the motor becomes a generator and sends energy back to the batteries. It is explained as f o l l o w s, b e c a u se the

w h e e l s o f a d e c e l e r a t i n g v e h i c l e a r e st i l l m o v i n g f o r wa r d , t h e y c a n b e m a d e t o t u r n t h e e l e c t r i c m o t o r , wh i c h t h e n f e e d s e n e r g y t o t h e b a t t e r i e s f o r st o r a g e . T h e s y st e m b e c o m e s , i n e f f e c t , a

g e n e r a t o r , wh i c h p r o v i d e s b r a k i n g f o r c e wh i l e i t c o n ve r t s the vehicles kinetic energy into a

r e u sa b l e f o r m - e l e c t r i c a l e n e r g y . W h e n t h e a c c e l e r a t o r p e d a l i s r e l e a se d , t h e a b s e n c e o f p r e s su r e t r i g g e r s a r e sp o n s e f r o m t h e Energy St o r a g e Unit ( E S U) . R e g e n e r a t i ve

b r a k i n g b e g i n s, a n d t h e b a t t e r i e s a r e r e - c h a r g e d b y t h e m o t o r , wh i c h i s t u r n e d b y t h e w h e e l s. I n

t h i s c a se , t h e f r i c t i o n b r a k e s a r e n o t e n g a g e d . If more vigorous deceleration is required, and t h e b r a k e p e d a l i s d e p r e ss e d , t h i s e n g a g e s b o t h s e t s o f b r a k e s. e f f i c i e n c y, it is H o we ve r , t o m a x i m i z e e n e r g y a d va n t a g e o u s as such as to apply the it

r e g e n e r a t i ve

brake

possible

t h e r e f o r e t e n d s t o d o m o r e o f i t s t o t a l wo r k i n t h e f i r st p a r t o f t h e b r a k i n g m o t i o n . T h e r e a r e t wo d e c e l e r a t i o n m o d e s: 1. Foot off throttle but not on brake pedal in this mode, the c h a r g e / a ss i st gauge will sh o w

p a r t i a l c h a r g e , a n d t h e ve h i c l e wi l l sl o w d o w n gradually. 2. Foot on brake pedal - In this mode, a higher a m o u n t o f r e g e n e r a t i o n wi l l b e a l l o we d , a n d t h e v e h i c l e wi l l sl o w m o r e r a p i d l y. D u r i n g l i g h t b r a k e p e d a l a p p l i c a t i o n , o n l y t h e I MA m o t o r / / g e n e r a t o r i s sl o w i n g t h e c a r . W i t h h e a vi e r b r a k e p e d a l a p p l i c a t i o n , t h e c o n ve n t i o n a l f r i c t i o n b r a k e s a l so c o m e i n t o p l a y. W h e n d e c e l e r a t i n g , r e g e n e r a t i o n wi l l c o n t i n u e u8ntil engine speed falls to about 1000 rpm. At

t h i s p o i n t , t h e d r i v e r wi l l t yp i c a l l y sh i f t i n t o neutral.

D I A GR A M O F A R EG E N. B R A KI NG S Y S TE M

REGEN. BRAKING IN RAIL VEHICLES

 D yn a m i c B r a k i n g h a s b e e n f r e q u e n t l y u se d i n r a i l ve h i c l e s t o r e d u c e b r a k e we a r : Dynamic braking is the use of the electric traction motors of a vehicle as generators when slowing. It is termed

rheostatic if the generated electrical power is dissipated

as heat in brake grid resistors, and regenerative if the power is returned to the supply line. Dynamic braking lowers the wear of friction-based braking components, and additionally regeneration reduces energy consumption. Traction motor refers to an electric motor providing the primary rotational torque of a machine, usually for conversion into linear motion (traction). S o m e e l e c t r i c r a i l / o ve r h e a d l i n e l o c o m o t i ve s w i t h r e g e n e r a t i ve b r a k i n g c a n se n d p o w e r back through supply line: A regen. braking system used by locomotives and trains fitted with electric traction motors where the motors become generators and the current developed is fed into the overhead line or third rail for use by other trains or for return to the supplier. When the driver of a train wants to stop or
slow down a train, he applies regenerative braking. The motors of the locomotives which are normally pulling the train, change their mode of operation from motor to a generator. The mechanical energy of the train is converted to electrical energy by the generator, which then goes to the power supply grid. This feature is called regenerative braking. Thus, even braking losses are gainfully utilised in three phase locomotives.

Pointedly, over the years, the technology upgradation has taken place in electric locomotives, which has contributed in overall objective of Railways to conserve precious electric energy. With this objective in mind, 3 phase locomotives were inducted into Railways almost 15 years ago. Initially, these locomotives were imported from Switzerland on ToT basis (Transfer of Technology). As per this agreement, when complete equipment is imported, the foreign company also undertakes to transfer the entire knowhow to the indigenous company for enabling the latter to manufacture the imported equipment in the country. After 5 years, CLW (Chitranjan Locomotives Works) started the production of three phase locomotive indigenously gradually reducing the import content to 5% only.

North Central Railway runs around 250 passenger trains and 150 trains every day by electric locomotives. Out of these, about 25% of trains are run by about three phase locomotives. Since drivers running such locomotives were required to be given special training to utilise this feature, NCR has trained all its drivers to utilise regenerative braking. Due to intelligent application of this feature, NCR has saved about 15 million units of electricity costing Rs 6 crores.

REGEN. BRAKING IN ROAD VEHICLE

Hydraulic Regenerative Braking (HRB) has already been proposed for Heavy Duty Trucks [4] to recover the braking energy with a high efficiency on a regenerative loop. When the driver steps on the brake, the vehicle's kinetic energy powers a reversible pump, which sends hydraulic fluid from a low pressure reservoir inside the vehicle into a high pressure accumulator. The pressure is created by compressing nitrogen gas in the accumulator as the fluid

is pumped in to displace the nitrogen. This slows the vehicle and helps bringing it to a stop. The fluid remains under pressure in the accumulator until the driver pushes the accelerator again. Then the pump reverses and the pressurized fluid is used to accelerate the vehicle, effectively translating the kinetic energy that the truck had before braking into mechanical energy that helps to speed up the vehicle again. It is predicted that a system like this could store 80% of the momentum lost by a vehicle during deceleration and use it to get the vehicle moving again. Actual regenerative cycle efficiencies are probably smaller than that.So far, HRB systems have been used primarily as proofs of concept and in demonstration projects only. They are not ready for production models. These hydraulic brakes are noisy and prone to leaks and the accumulators take up a considerable amount of space. Once all of these issues are solved, such systems will probably be most useful in large trucks weighing 4,500 kilograms or more, where hydraulic brakes may prove to be a more optimal system than much less efficient electronically controlled regenerative brakes.

CARS WITH REGEN. BRAKING

Toyota Prius Honda Insight Ford Escape Hybrid Tesla Roadster Chevy Volt

T Y OT A PR I US

BENEFITS OF REGEN. BRAKING

Energy Conservation:
T h e f l yw h e e l a b s o r b s e n e r g y wh e n b r a k i n g v i a a c l u t c h s y st e m s l o wi n g t h e c a r d o w n a n d s p e e d i n g u p t h e wh e e l . To a c c e l e r a t e , a n o t h e r c l u t c h s y st e m c o n n e c t s t h e f l y wh e e l t o t h e d r i ve t r a i n , sp e e d i n g u p t h e c a r a n d sl o wi n g d o w n t h e f l y wh e e l . En e r g y i s t h e r e f o r e c o n se r ve d r a t h e r t h a n w a s t e d a s h e a t a n d l i g h t w h i c h i s wh a t

n o r m a l l y h a p p e n s i n t h e c o n t e m p o r a r y s h o e / d i sc system.

Wear Reduction:
I n r e g e n e r a t i ve r a k i n g , w h e n 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 si st s t h e t u r n i n g o f t h e wh e e l s, c a p t u r i n g so m e o f t h e e n e r g y o f m o t i o n a s i f i t we r e a g e n e r a t o r a n d returning that energy to the battery pack. mechanical extending brakes; brake life l e ss e n i n g is not wear In and Th i s

p o s si b l e .

r e d u c e s t h e u se o f u se t h e b r a k e .

Fuel Consumption:
The fuel consumption and of the conventional s y st e m

vehicles

regenerative

braking

v e h i c l e s wa s e va l u a t e d o v e r a c o u r s e o f va r i o u s f i x e d u r b a n d r i vi n g sc h e d u l e s. compared as shown in figure. The results are Representing the

s i g n i f i c a n t c o st sa yi n g t o i t s o wn e r , i t h a s b e e n p r o ve d the r e g e n e r a t i ve braking is very fuel -

efficient.

Braking is not total loss:

C o n ve n t i o n a l b r a k e s a p p l y f r i c t i o n t o c o n ve r t a vehicles kinetic energy into heat. In energy

t e r m s, t h e r e f o r e , b r a k i n g i s a t o t a l l o s s: o n c e h e a t i s g e n e r a t e d , i t i s v e r y d i f f i c u l t t o r e u se . The r e g e n e r a t i ve braking s y st e m , h o we ve r ,

s l o w s a ve h i c l e d o wn i n a d i f f e r e n t w a y .

DOWNSIDES
Added complexity of brake control system Only works for wheels connected to motors Friction brakes are still necessary

CONCLUSION
Theoretical i n ve st i g a t i o n s of a r e g e n e r a t i ve b r a k i n g s ys t e m sh o w a b o u t 2 5 % s a vi n g i n f u e l c o n su m p t i o n . T h e l o w e r o p e r a t i n g a n d e n vi r o n m e n t c o st s o f a vehicle with it r e g e n e r a t i ve more braking s ys t e m than a

should

make

a t t r a c t i ve

c o n ve n t i o n a l o n e .

T h e t r a d i t i o n a l c o st o f t h e

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

The

exhaust

e m i s si o n braking

of

ve h i c l e wo u l d

u si n g be

the much as

r e g e n e r a t i ve less than

concept

e q u i va l e n t

c o n ve n t i o n a l

ve h i c l e s

l e s s f u e l a r e u se d f o r c o n s u m p t i o n . T h e s e sy s t e m s a r e p a r t i c u l a r l y su i t a b l e i n d e v e l o p i n g c o u n t r i e s su c h a s I n d i a wh e r e b u se s a r e t h e p r e f e r r e d m e a n s o f t r a n s p o r t a t i o n wi t h i n t h e c i t i e s.