report ebike

8/4/2019 Report Ebike

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CERTIFICATE

This is to certify that project report entitled MOTOR POWERED CYCLE WITH

REGENERATIVE SYSTEM which is submitted by in partial fulfillment of the requirement for

the award of degree B.tech in department of Mechanical Engineering of Indraprastha University,

is a record of candidates own work carried out by them under my supervision.

DATE:

SUPERVISOR:

ACKNOWLEDGEMENT


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We would like to express our gratitude to faculty member in department of mechanical

engineering, under whom this project has come to this stage. Without his able guidance and

support, we would have not been able to complete this project report.

We would like to thank all other faculty member who helped us to get through hitches and

showed us the right way to carry out the project. Last but not the least; we would also like to

acknowledge the contribution of the staff members for their assistance and cooperation during

the work.

INDEX

CONTENTS PAGE No.

Abstract-------------------------------------------------------------------------------1

List of Abbreviations----------------------------------------------------------------2


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Introduction

Electric Bicycle----------------------------------------------------------------------3

Regenerative Braking System-----------------------------------------------------5

Problem Definition-----------------------------------------------------7

Literature review

Bicycle--------------------------------------------------------------------8

History--------------------------------------------------------------------------------9

Regenerative braking system components--------------------------------------13

Dynamo-----------------------------------------------------------------------------14

Sprocket-----------------------------------------------------------------------------19

Electric motor----------------------------------------------------------------------20

Battery-------------------------------------------------------------------------------24

Chain---------------------------------------------------------------------------------30

Regenerative braking in latest cars-----------------------------------------------33

Working of RBS in automobiles--------------------------------------------------34

Diagram showing the working of RBS in Car----------------------------------35

Background of the Invention------------------------------------------------------37

Summary of the Invention---------------------------------------------------------39

Regenerative Braking System in Locomotives---------------------------------42

Comparison of Dynamic and Regenerative Brakes----------------------------43


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Disadvantages-----------------------------------------------------------------------44

Design considerations

Dynamo------------------------------------------------------------------------------45

D.c motor----------------------------------------------------------------------------46

Sprocket-----------------------------------------------------------------------------47

Battery-------------------------------------------------------------------------------48

Switches-----------------------------------------------------------------------------49

Lamp---------------------------------------------------------------------------------49

Description of components--------------------------------------------------------51

Findings/calculations

Observations------------------------------------------------------------------------52

Calculations-------------------------------------------------------------------------53

Result-------------------------------------------------------------------- 56

Conclusion------------------------------------------------------------- 57

Cost Estimation--------------------------------------------------------

Future scope-----------------------------------------------------------58

Legal issues of electric bicycles-------------------------------------------------63

References------------------------------------------------------------- 64


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ABSTRACT

ELECTRIC BICYCLE

An electric bicycle is abicycle with an electric motor used to power the vehicle, or to assist with

pedaling. In many parts of the world, electric bicycles are classified as bicycles rather than motor
http://en.wikipedia.org/wiki/Bicyclehttp://en.wikipedia.org/wiki/Bicycle


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vehicles, so they are not subject to the same laws as motor vehicles. Electric bicycles are one

type ofmotorized bicycle.

R.B.S

When riding a vehicle, a great amount of kinetic energy is lost when braking, making cycling

fairly strenuous. The goal of our project was to develop a product that stores the energy which is

normally lost during braking, and reuses it to help propel the rider when starting. This was

accomplished with a Generator fitted with rubber wheel whose parameters were optimized based

on engineering, consumer preference, and manufacturing models. The resulting product is one

which is practical and potentially very profitable in the market place.

In this project we utilise the heat energy purposefully which is lost by applying brakes. After

applying brake on the wheel the kinetic energy of wheel is transferred to the rubber wheel

attached to the generator which is then transformed in the electrical energy. This electrical

energy is used to lightening the LED. We can also use this energy for other purpose by storing in

the battery.

LIST OF ABBREVIATIONS

E-Bike Electric Bicycle

RBS Regenerative Braking System

SLA Sealed Lead Acid Battery
http://en.wikipedia.org/wiki/Motorized_bicyclehttp://en.wikipedia.org/wiki/Motorized_bicycle


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D.C Direct Current

P.M Permanent Magnet

E.M.F Electro Motive Force

Ah Ampere Hour

V - Volts

INTRODUCTION

ELECTRIC BICYCLE


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An Electric Bike is a battery operated vehicle that is very economical with low maintenance cost

and zero pollution. Electric two wheelers use the electrical technology of rechargeable battery

that converts the electrical energy into mechanical energy. The battery of an EV can be charged

easily using a power connection.

Electric bikes, light in weight, trendy, efficient and eco-friendly, are becoming potent alternative

to the conventional two-wheelers and the Electric two-wheeler industry in India is developing at

rapid speed.

Some of the unavoidable advantages of Electric Bikes :

Licence and registration is not required for E Bikes and Scooters.

Electric two wheelers run on re-chargeable battery and uses electricity as fuel in place of

conventional Petrol/Diesel.

E Bikes and Scooters can beat the rising prices of Petrol/Diesel.

Simple design, light weight and economical Electric vehicles are very low in running and

maintenance cost.

With the ease of handling, Electric two wheelers saves the commuting time in congested

roads specially in urban areas.

Electric vehicles are more efficient in terms of generating usable energy from their

electric engine's battery in comparison to the regular fuelconversion. In this way EBikesand Scooters are innovative and efficient mode of personal transport.

Electric bikes or scooters use electricity therefore no emission of harmful gases like

Carbon dioxide (CO2) or Nitrogen dioxide (NO2).

PRACTICALITY BENEFITS FROM POWER ASSISSTANCE

Adding electric power to a bicycle can help guarantee multiple benefits of cycling and


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greatly increase usability. Electric bicycles enable a better use of time, additional energy

for longer distances at greater speed, and perhaps some extra power for additional cargo.

Greater speed and range enable an electric bicycle to address multiple needs at one

time (combining time-sensitive commuting with exercise, for example).

The additional power permits the ability to transport (or towing of) more cargo.

Good design enables a rider to work up a sweat, or to stay dry and fresh, depending on

his or her desires for each particular trip.

The thrill and handling of a good design and great performance increases motivation

to use a bicycle. Electric drive can add some real fun to the experience of a bicycle.

ECONOMIC AND ENVIRONMENTAL BENEFITS

A major reason for the explosive popularity of electric bicycles is, of course, the economy.

The increases in fuel prices increase peoples interest when battery technology and electric drive

have achieved important gains. Electric bicycles have reached a strategically important state of

the art at the best possible time.

Electric bikes or scooters use electricity therefore no emission of harmful gases like Carbon

dioxide (CO2) or Nitrogen dioxide (NO2).

REGENERATIVE BRAKING SYSTEM

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

of the kinetic energy that would otherwise be lost to heat when braking and make use of that


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power either by storing it for future use or feeding it back into a power system for other vehicles

to use.

Brakes as an Electrical Generator

Regenerative brakes are a form of dynamo generator, originally discovered in 1832 by Hippolyte

Pixii. The dynamo's rotor slows as the kinetic energy is converted to electrical energy through

electromagnetic induction. The dynamo can be used as either generator or brake by converting

motion into electricity or be reversed to convert electricity into motion.

Using a dynamo as a regenerative brake was discovered co-incident with the modern electric

motor. In 1873, Znobe Gramme attached the wires from two dynamos together. When one

dynamo rotor was turned as a regenerative brake, the other became an electric motor.

It is estimated that regenerative braking systems in vehicles currently reach 31.3% electric

generation efficiency, with most of the remaining energy being released as heat; the actual

efficiency depends on numerous factors, such as the state of charge of the battery, how many

wheels are equipped to use the regenerative braking system, and whether the topology used is

parallel or serial in nature.

Electric brakes have been used in vehicles with electric motors since the early-20th century on

record, The Warner Electric Brake Corporation was using electric brakes in 1927; but it is

possible that they were using electric brakes even earlier.

Regenerative brakes in electric railway vehicles feed the generated electricity back into the grid.

In battery electric and hybrid electric vehicles, the energy is stored in a battery or bank of

capacitors for later use.

It is usual for vehicles to include a 'back-up' system so that friction braking is applied

automatically if the connection to the power supply is lost. Also, in a DC system or in an AC

system that is not directly grid connected via simple transformers, special provision must also be

made for situations where more power is being generated by braking than is being consumed by

other vehicles on the system.


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A small number of mountain railways have used 3-phase power supplies and 3-phase induction

motors and have thus a near constant speed for all trains as the motors rotate with the supply

frequency both when giving power or braking.

PROBLEM DEFINITION


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When riding a vehicle, a great amount of kinetic energy is lost when braking, making cycling

fairly strenuous. The goal of our project was to develop a product that stores the energy which is

normally lost during braking, and reuses it to help propel the rider when starting. This was

accomplished with a Generator fitted with rubber wheel whose parameters were optimized based

on engineering, consumer preference, and manufacturing models. The resulting product is one

which is practical and potentially very profitable in the market place.

In this project we utilize the heat energy purposefully which is lost by applying brakes. After

applying brake on the wheel the kinetic energy of wheel is transferred to the rubber wheel

attached to the generator which is then transformed in the electrical energy. This electrical

energy is used for lightening purposes. We can also use this energy for other purpose by storing

in the battery.

LITERATURE REVIEW


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BICYCLE

A bicycle, also known as a bike, pushbike or cycle, is a pedal-driven, human-powered, single-

track vehicle, having two wheels attached to a frame, one behind the other. A person who rides a

bicycle is called a cyclist or a bicyclist.

Bicycles were introduced in the 19th century and now number about one billion worldwide,

twice as many as automobiles. They are the principal means of transportation in many regions.

They also provide a popular form of recreation, and have been adapted for such uses as children's

toys, adult fitness, military and police applications, courier services andbicycle racing.

HISTORY
http://en.wikipedia.org/wiki/Human-powered_transporthttp://en.wikipedia.org/wiki/Single-track_vehiclehttp://en.wikipedia.org/wiki/Single-track_vehiclehttp://en.wikipedia.org/wiki/Bicycle_wheelhttp://en.wikipedia.org/wiki/Bicycle_framehttp://en.wikipedia.org/wiki/Mode_of_transporthttp://en.wikipedia.org/wiki/Bicycle_racinghttp://en.wikipedia.org/wiki/Human-powered_transporthttp://en.wikipedia.org/wiki/Single-track_vehiclehttp://en.wikipedia.org/wiki/Single-track_vehiclehttp://en.wikipedia.org/wiki/Bicycle_wheelhttp://en.wikipedia.org/wiki/Bicycle_framehttp://en.wikipedia.org/wiki/Mode_of_transporthttp://en.wikipedia.org/wiki/Bicycle_racing


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Brake

A brake is a device for slowing or stopping the motion of a machine or vehicle, and to keep itfrom starting to move again. The kinetic energy lost by the moving part is usually translated to

heat by friction. Alternatively, in regenerative braking, much of the energy is recovered and

stored in a flywheel, capacitor or turned into alternating current by an alternator, then rectified

and stored in a battery for later use.

Brakes of some description are fitted to most wheeled vehicles, including automobiles of all

kinds, trucks, trains, motorcycles, and bicycles. Baggage carts and shopping carts may have them

for use on a moving ramp. Some airplanes are fitted with wheel brakes on the undercarriage.Some aircraft also feature air brakes designed to slow them down in flight. Notable examples

include gliders and some WWII-era fighter aircraft. These allow the aircraft to maintain a safe

speed in a steep descent. The Saab B 17 dive bomber used the deployed undercarriage as an air

brake.'

Early braking systems, used to stop vehicles with steel rimmed wheels, consisted of a curved

wooden block designed to bear against the steel tire when manipulated by a single leverage

system from the drivers seat.

This "brake shoe" was the normal way of braking either a horse drawn vehicle or steam

locomotive. Many varieties of arrangements of levers, rods and pivots were utilized to bring

them into operation.

In 1895 the Michelin Brothers had begun the move towards replacing steel rimmed wheels with

the pneumatic rubber tire forcing them to think of a new braking system as "brake shoes" were

no longer satisfactory.

A new method of braking was required and two early devices attempted to apply the force of

friction to the axle or to a drum on the axle or transmission shaft. This type of brake was actuated

by the driver depressing a pedal or operating a lever. Heavier pressure caused the bands to

contract more tightly around the drum giving greater retardation.


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One included the use of a wooden block inside a flexible contracting metal band which when

pressed together would tighten around the drum causing friction between the drum, which is

connected to the wheel, and the wooden blocks and therefore slowing down the wheel.

The other was an inner wheel or brake drum which was added with an external contracting band

meant to bear against the drum to retard the vehicle. However, continuous replacement of drum

and band combined with poor friction quality, soon led to the lining the band with a replacement

friction material. Lead, cotton and camel hair were used as lining, but they burned out too

quickly which led Herbert Frood to produce an asbestos fabric in 1908.

In 1899 Daimler had a cable wound around a drum and anchored to the chassis so that when the

cable was tightened while the car was moving forwards the rotation of the drum increased the

tightness and grip of the cable, therefore reducing the amount of force required to pull the lever

or press on the pedal in order to stop the vehicle. However, in reverse it tended to work against

the pull of the cable and loosen its grip.

The "added" braking efficiency called "servo assistance" is still an important factor in the design

of drum brakes today. Most modern cars have vacuum assisted braking.

The external band brake was vulnerable to road dirt and weathering which caused rapid wear of

lining, loss of efficiency and on occasions "automatic" brake application due to drum expansion.

To overcome these problems the internal expanding shoe brake was developed, in which the

brake shoes were inside a 'brake drum' (protected from weather and dust).

Its first appearance seems to have been with Louis Renault in 1902 and remained the basic

principle for the next fifty years.

Originally, motor car brakes were operated by mechanical means and became known as

"mechanical" brakes i.e. a mechanical system was used to transform the effort of the driver's foot

on the brake pedal into expansion of the brake shoes against the drum. (On depressing the brake

pedal, the cam is rotated by a lever connected to the pedal and forces the shoes into contact with

the brake drum. Springs attached to both shoes return the shoes to the original "off" position

when the brakes are released.)


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Rear cantilever brake assembly on a bicycle.

To this day, bicycles have mechanical brakes, operated by hand lever and cable. This closes

calipers, containing the friction pads, onto the rim of the wheel.

One solution, by Maurice Farman 1920, to the challenge of increasing the "servo action" was to

connect two shoes with a pivot and secure the other end of the "trailing" shoe, with a pivot, to the

back plate. This in effect made both shoes "leading shoes".

Early brakes were operated by a linkage system of fixed rods and levers supplement by Bowden

cables (Cables were invented in 1906 and were developed for the bicycle). The linkage system ofrods and levers were not easy to keep in good operating order. Equalizing brake pressure on the

wheels also presented a number of problems, many of which were solved by the introduction of

the hydraulic system, using fluid to transfer the force applied to the brake pedal.

Hydraulic systems make use of the fact liquids cannot be compressed to any appreciable degree

and that pressure applied at any points within a closed system is transmitted equally throughout(Pascal's law).

In a basic hydraulic braking system all the cylinders and brake lines form one closed system

filled with brake fluid. The master cylinder has a single piston, whiles each wheel cylinder has

two opposed pistons. All pistons have rubber cups to maintain pressure and prevent loss of fluid.

The pressure generated in the master cylinder is transmitted with equal and undiminished force

to the pistons of each wheel cylinder so that pressures applied to all brake shoes are identical.

Most modern cars now have disc brakes. The brake pads are mounted within the jaws of a

caliper, which grips a brake disc, providing the necessary friction. Performance cars are fitted

with larger wheels, to permit larger brake discs.


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Regenerative Braking System

Description

Our project named EBIKE with RBS has following components:

1. Bicycle

2. Dynamo

3. Sprocket

4. D.C Motor

5. Battery

6. Chain

7. Indicator

8. Horn

9. Switches

10.Lamp


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Dynamics

A bicycle stays upright while moving forward by being steered so as to keep its center of gravity

over the wheels. This steering is usually provided by the rider, but under certain conditions may

be provided by the bicycle itself.

The combined center of mass of a bicycle and its rider must lean into a turn to successfully

navigate it. This lean is induced by a method known as countersteering, which can be performed

by the rider turning the handlebars directly with the hands [8] or indirectly by leaning the bicycle.

Short-wheelbase ortall bicycles, when braking, can generate enough stopping force at the front

wheel to flip longitudinally. The act of purposefully using this force to lift the rear wheel and

balance on the front without tipping over is a trick known as a stoppie, endo or front wheelie.

DYNAMO

The Dynamo was the first electrical generator capable of delivering power for industry. The

dynamo uses electromagnetic principles to convert mechanical rotation into an alternating

electric current. A dynamo machine consists of a stationary structure which generates a strong

magnetic field, and a set of rotating windings which turn within that field. On small machines the

magnetic field may be provided by a permanent magnet; larger machines have the magnetic field

created by electromagnets.

The first dynamo based on Faraday's principles was built in 1832 by Hippolyte Pixii, a French

instrument maker. It used a permanent magnet which was rotated by a crank. The spinning

magnet was positioned so that its north and south poles passed by a piece of iron wrapped with

wire. Pixii found that the spinning magnet produced a pulse of current in the wire each time a

pole passed the coil. Furthermore, the north and south poles of the magnet induced currents in

opposite directions. By adding a commutator, Pixii was able to convert the alternating current to

direct current.

Unlike the Faraday disc, many turns of wire connected in series can be used in the moving

windings of a dynamo. This allows the terminal voltage of the machine to be higher than a disc

can produce, so that electrical energy can be delivered at a convenient voltage.
http://en.wikipedia.org/wiki/Center_of_masshttp://en.wikipedia.org/wiki/Countersteeringhttp://en.wikipedia.org/wiki/Bicycle#cite_note-Wilson-7http://en.wikipedia.org/wiki/Tall_bikehttp://en.wikipedia.org/wiki/Stoppiehttp://en.wikipedia.org/wiki/Electromagnetismhttp://en.wikipedia.org/wiki/Current_(electricity)http://en.wikipedia.org/wiki/1832http://en.wikipedia.org/wiki/Hippolyte_Pixiihttp://en.wikipedia.org/wiki/Commutator_(electric)http://en.wikipedia.org/wiki/Center_of_masshttp://en.wikipedia.org/wiki/Countersteeringhttp://en.wikipedia.org/wiki/Bicycle#cite_note-Wilson-7http://en.wikipedia.org/wiki/Tall_bikehttp://en.wikipedia.org/wiki/Stoppiehttp://en.wikipedia.org/wiki/Electromagnetismhttp://en.wikipedia.org/wiki/Current_(electricity)http://en.wikipedia.org/wiki/1832http://en.wikipedia.org/wiki/Hippolyte_Pixiihttp://en.wikipedia.org/wiki/Commutator_(electric)


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The relationship between mechanical rotation and electric current in a dynamo is reversible; the

principles of the electric motor were discovered when it was found that one dynamo could cause

a second interconnected dynamo to rotate if current was fed through it.


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Terminology

The parts of a dynamo or related equipment can be expressed in either mechanical terms or

electrical terms. Although distinctly separate, these two sets of terminology are frequently used

interchangeably or in combinations that include one mechanical term and one electrical term.

This causes great confusion when working with compound machines such as a brushless

alternator or when conversing with people who are used to working on a machine that is

configured differently than the machines that the speaker is used to.

Types of Dynamos

There are three types of dynamos available, each with different attributes.

Bottle Dynamos

Dynamos that rub against the tire rim have a few undesirable properties. They are noisy, they can

slip when wet, and they wear the sidewall of the tire. The problem of slippage was solved on the

higher end dynamos by the optional use of a material that provides more friction with the tire

(which increases the wear even more). On a tire with thick sidewalls the wear is not such a bigdeal. On a lightweight tire with thin sidewalls, the wear will require more frequent tire changes.

Bottle dynamos remain the most popular type.

Bottom Bracket or Roller Dynamos

This dynamo is mounted near the bottom bracket and contacts the tread of rear wheel. Thisdynamo does not wear the tire sidewall, but the location near the ground subjects it to dirt and

moisture. Some touring bicycles have wiring through the frame, from the bottom bracket area up

to the headset, for bottom bracket dynamos (I have an old touring bicycle with this feature).

These dynamos are no longer popular, but they are still available from Union and a light set with

this dynamo is $70 and includes a 2.4W headlight, and 0.6W tail light.


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Mechanical

Rotor: The rotating part of an alternator, generator, dynamo or motor.Stator: The stationary part of an alternator, generator, dynamo or motor.

Electrical

Armature: The power-producing component of an alternator, generator, dynamo or motor. The

armature can be on either the rotor or the stator.

Field: The magnetic field component of an alternator, generator, dynamo or motor. The field can

be on either the rotor or the stator and can be either an electromagnet or a permanent magnet.

Maximum power

The maximum power theorem applies to generators as it does to any source of electrical energy.

This theorem states that the maximum power can be obtained from the generator by making the

resistance of the load equal to that of the generator. However, under this condition the power

transfer efficiency is only 50%, which means that half the power generated is wasted as heat and

Lorentz force or back emf inside the generator. For this reason, practical generators are not

usually designed to operate at maximum power output, but at a lower power output where

efficiency is greater.

Regenerative braking is used on hybrid gas/electric automobiles to recoup some of the energy

lost during stopping. This energy is saved in a storage battery and used later to power the motor

whenever the car is in electric mode.

Understanding how regenerative braking works may require a brief look at the system it

replaces. Conventional braking systems use friction to counteract the forward momentum of a

moving car. As the brake pads rub against the wheels (or a disc connected to the axle), excessive

heat energy is also created. This heat energy dissipates into the air, wasting up to 30% of the car's

generated power. Over time, this cycle of friction and wasted heat energy reduces the car's fuel

efficiency. More energy from the engine is required to replace the energy lost by braking.
http://en.wikipedia.org/wiki/Maximum_power_theoremhttp://en.wikipedia.org/wiki/Maximum_power_theorem


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Regenerative braking does more than simply stop the car. Electric motors and electric generators

(such as a car's alternator) are essentially two sides of the same technology. Both use magnetic

fields and coiled wires, but in different configurations. Regenerative braking systems take

advantage of this duality. Whenever the electric motor of a hybrid car begins to reverse direction,

it becomes an electric generator or dynamo. This generated electricity is fed into a chemical

storage battery and used later to power the car at city speeds.

Regenerative braking takes energy normally wasted during braking and turns it into usable

energy. It is not, however, a perpetual motion machine. Energy is still lost through friction with

the road surface and other drains on the system. The energy collected during braking does not

restore allthe energy lost during driving. It does improve energy efficiency and assist the main

alternator.

As per faradays law of electromagnetic induction:

E= --/ t,

Where, is magnetic flux linked with coil

=B.A

Where, B=magnetic field

A=area of cross section


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SPROCKET

A sprocket is a profiled wheel with teeth that meshes with a chain,trackor other perforated or

indented material. It is distinguished from a gear in that sprockets are never meshed together

directly, and differs from apulley by not usually having a flange at each side.

Sprockets are used in bicycles, motorcycles, cars,tanks, and othermachinery either to transmit

rotary motion between two shafts where gears are unsuitable or to impart linear motion to a

track, tape etc.

In the case of bicycle chains, it is possible to modify the overall gear ratio of the chain drive by

varying the diameter (and therefore, the tooth count) of the sprockets on each side of the chain.

This is the basis ofDerailleur gears. A 10-speed bicycle, by providing two different-sized driving

sprockets and five different-sized driven sprockets, allows up to ten different gear ratios. The

resulting lower gear ratios make the bike easier to pedal up hills while the higher gear ratios

make the bike faster to pedal on flat roads. In a similar way, manually changing the sprockets on

a motorcycle can change the characteristics ofacceleration and top speed by modifying the final

drive gear ratio.

The dimensions of a sprocket can be calculated as follows, where P is the pitch of the chain, and

N is the number of teeth on the sprocket;

Pitch Diameter = P sin (180 N)

Outside Diameter = P (0.6 + cot ( 180 N) )

Sprocket thickness = 0.93 Roller Width - 0.006"
http://en.wikipedia.org/wiki/Wheelhttp://en.wikipedia.org/wiki/Roller_chainhttp://en.wikipedia.org/wiki/Caterpillar_trackhttp://en.wikipedia.org/wiki/Gearhttp://en.wikipedia.org/wiki/Pulleyhttp://en.wikipedia.org/wiki/Flangehttp://en.wikipedia.org/wiki/Bicyclehttp://en.wikipedia.org/wiki/Motorcyclehttp://en.wikipedia.org/wiki/Automobilehttp://en.wikipedia.org/wiki/Tankhttp://en.wikipedia.org/wiki/Machinehttp://en.wikipedia.org/wiki/Gear_ratiohttp://en.wikipedia.org/wiki/Bicycle_chainhttp://en.wikipedia.org/wiki/Derailleur_gearshttp://en.wikipedia.org/wiki/Accelerationhttp://en.wikipedia.org/wiki/Speedhttp://en.wikipedia.org/wiki/Gear_ratiohttp://en.wikipedia.org/wiki/Wheelhttp://en.wikipedia.org/wiki/Roller_chainhttp://en.wikipedia.org/wiki/Caterpillar_trackhttp://en.wikipedia.org/wiki/Gearhttp://en.wikipedia.org/wiki/Pulleyhttp://en.wikipedia.org/wiki/Flangehttp://en.wikipedia.org/wiki/Bicyclehttp://en.wikipedia.org/wiki/Motorcyclehttp://en.wikipedia.org/wiki/Automobilehttp://en.wikipedia.org/wiki/Tankhttp://en.wikipedia.org/wiki/Machinehttp://en.wikipedia.org/wiki/Gear_ratiohttp://en.wikipedia.org/wiki/Bicycle_chainhttp://en.wikipedia.org/wiki/Derailleur_gearshttp://en.wikipedia.org/wiki/Accelerationhttp://en.wikipedia.org/wiki/Speedhttp://en.wikipedia.org/wiki/Gear_ratio


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Application

Sprockets should be accurately aligned in a common vertical plane, with their axes parallel.

Chain should be kept clean and well lubricated with a thin, light-bodied oil that will penetrate the

small clearances between pins and bushings. Center distance should not be less than 1.5 times

the diameter of the larger sprocket, nor less than 30 times the chain pitch, and should not exceed

60 times the chain pitch. Center distance should be adjustable - one chain pitch is sufficient - and

failing this an idler sprocket should be used to adjust tension. A little slack is desirable,

preferably on the bottom side of the drive.

The chain should wrap at least 120 around the drive sprocket, which requires a ratio of no more

than 3.5 to 1; for greater ratios, an idler sprocket may be required to increase wrap angle.

ELECTRIC MOTOR

An electric motor converts electrical energy into mechanical energy. Electric motors are found

in household appliances such as fans, fridges, washing machines, pool pumps and fan-forced

ovens.

Most electric motors work by electromagnetism.principle. The fundamental principle upon

which electromagnetic motors are based is that there is a mechanical force on any current-

carrying wire contained within a magnetic field. The force is described by the Lorentz force law

and is perpendicular to both the wire and the magnetic field. Most magnetic motors are rotary,

but linear motors also exist. In a rotary motor, the rotating part (usually on the inside) is called

the rotor, and the stationary part is called the stator. The rotor rotates because the wires and

magnetic field are arranged so that a torque is developed about the rotor's axis. The motor

contains electromagnets that are wound on a frame. Though this frame is often called the

armature, that term is often erroneously applied. Correctly, the armature is that part of the motor

across which the input voltage is supplied. Depending upon the design of the machine, either the

rotor or the stator can serve as the armature.


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The direct current (DC) motor is one of the first machines devised to convert electrical

power into mechanical power. Permanent magnet (PM) direct current convert

electrical energy into mechanical energy through the interaction of two magnetic fields.

One field is produced by a permanent magnet assembly, the other field is produced by

an electrical current flowing in the motor windings. These two fields result in a torque

which tends to rotate the rotor. As the rotor turns, the current in the windings is

commutated to produce a continuous torque output. The stationary electromagnetic

field of the motor can also be wire-wound like the armature (called a wound-field

motor) or can be made up of permanent magnets (called a permanent magnet motor).

In either style (wound-field or permanent magnet) the commutator. acts as half of a mechanical

switch and rotates with the armature as it turns. The commutator is composed of conductive

segments (called bars), usually made of copper, which represent the termination of

individual coils of wire distributed around the armature. The second half of the mechanical

switch is completed by the brushes. These brushes typically remain stationary with the

motor's housing but ride (or brush) on the rotating commutator. As electrical energy is

passed through the brushes and consequently through the armature a torsional force is

generated as a reaction between the motor's field and the armature causing the motor's

armature to turn. As the armature turns, the brushes switch to adjacent bars on the

commutator. This switching action transfers the electrical energy to an adjacent winding on

the armature which in turn perpetuates the torsional motion of the armature.


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Permanent magnet (PM) motors are propably the most commonly usedDC motors, but there are

also some other type of DC motors(types which use coils to make the permanent magentic

field also).DC motors operate from a direct current power source. Movement of the

magnetic field is achieved by switching current between coils within the motor. This action

is called "commutation". Very many DC motors (brush-type) have built-in commutation,

meaning that as the motor rotates, mechanical brushes automatically commutate coils on the

rotor. You can use dc-brush motors in a variety of applications. A simple, permanent-magnet

dc motor is an essential element in a variety of products, such as toys, servo mechanisms,

valve actuators, robots, and automotive electronics. There are several typical advantages of a

PM motor. When compared to AC or wound field DC motors, PM motors are usually

physically smaller in overall size and lighter for a given power rating. Furthermore, since the

motor's field, created by the permanent magnet, is constant, the relationship between torque

and speed is very linear. A PM motor can provide relatively high torque at low speeds and

PM field provides some inherent self-braking when power to the motor is shutoff. There are

several disadvanges through, those being mostly being high current during a stall condition

and during instantaneous reversal. Those can damage some motors or be problematic to

control circuitry. Furthermore, some magnet materials can be damaged when subjected to

excessive heat and some loose field strength if the motor is disassembled.

High-volume everyday items, such as hand drills and kitchen appliances, use a dc servomotor

known as a universal motor. Those unisversal motors are series-wound DC motors, where

the stationary and rotating coils are wires in series. Those motors can work well on both AC

and DC power. One of the drawbacks/precautions about series-wound DC motors is that if

they are unloaded, the only thing limiting their speed is the windage and friction losses.

Some can literally tear themselves apart if run unloaded.

Sometimes the rotation direction needs to be changed. In normal permanent magnet motors, this

rotation is changedby changing the polarity of operating power (for example byswitching

from negative power supply topositive or by interchangingthe power terminals going to

power supply). This directrion chaning is typicaly implemented using relay or a circuit

called an H bridge. There are some typical characteristics on "brush-type" DC motors.


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When a DC motor is straight to a battery (with no controller), it draws a large surge current when

connected up. The surge is caused because the motor, when it is turning, acts as a generator.

The generated voltage is directly proportional to the speed of the motor. The current through

the motor is controlled by the difference between the battery voltage and the motor's

generated voltage (otherwise called back EMF). When the motor is first connected up to the

battery (with no motor speed controller) there is no back EMF. So the current is controlled

only by the battery voltage, motor resistance (and inductance) and the battery leads. Without

any back emf the motor, before it starts to turn, therefore draws the large surge current.

When a motor speed controller is used, it varies the voltage fed to the motor. Initially, at zero

speed, the controller will feed no voltage to the motor, so no current flows. As the motor

speed controller's output voltage increases, the motor will start to turn. At first the voltage

fed to the motor is small, so the current is also small, and as the motor speed controller's

voltage rises, so too does the motor's back EMF. The result is that the initial current surge is

removed, acceleration is smooth and fully under control.


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DC BIKE/SCOOTER MOTORS

MOTORS (VOLTS) - A 12 or 24 volt DC motor is easy to use. 24 Volt models are not quite as

powerful, but they require fewer heavy batteries. For a short commute (10 miles or less) on flat

ground, 24V might be the way to go. For longer commutes, especially if you need to get up a

hill, I'd suggest 36 Volts. The benefits of increasing your voltage beyond 36 quickly drop off

with the added weight of batteries, so if you're thinking of going for 48 Volts or more, don't

waste your time.

POLARITY - For a DC motor, polarity determines in which direction the motor spins, that's

which wire (plus or minus) goes on which motor terminal. Fortunately, you won't harm your

motor either way, but your bicycle might go backwards. Test your motor, if it spins the wrong

way, simply reverse the wires that go to the motor. For most motors neither way is right or

wrong.

BATTERY


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An electrical battery is a combination of one or more electrochemical cells, used to convert

stored chemical energy into electrical energy. Since the invention of the first Voltaic pile in 1800

by Alessandro Volta, the battery has become a common power source for many household and

industrial applications

Electrons collect on the negative terminal of the battery. If you connect a wire between the

negative and positive terminals, the electrons will flow from the negative to the positive terminal

as fast as they can (and wear out the battery very quickly -- this also tends to be dangerous,

especially with large batteries, so it is not something you want to be doing). Normally, you

connect some type ofload to the battery using the wire. The load might be something like a light

bulb, a motoror an electronic circuit like a radio.

Inside the battery itself, a chemical reaction produces the electrons. The speed of electron

production by this chemical reaction (the battery's internal resistance) controls how many

electrons can flow between the terminals. Electrons flow from the battery into a wire, and must

travel from the negative to the positive terminal for the chemical reaction to take place. That is

why a battery can sit on a shelf for a year and still have plenty of power -- unless electrons are

flowing from the negative to the positive terminal, the chemical reaction does not take place.

Once you connect a wire, the reaction starts. The ability to harness this sort of reaction started

with the voltaic pile.

Batteries are all over the place -- in our cars, ourPCs, laptops, portable MP3 players and cell

phones. A battery is essentially a can full of chemicals that produce electrons. Chemical

reactions that produce electrons are called electrochemical reactions.

If you look at any battery, you'll notice that it has two terminals. One terminal is marked (+), or

positive, while the other is marked (-), or negative. In an AA, C or D cell (normal flashlight

batteries), the ends of the battery are the terminals. In a large car battery, there are two heavy

lead posts that act as the terminals.
http://en.wikipedia.org/wiki/Electrochemical_cellhttp://en.wikipedia.org/wiki/Voltaic_pilehttp://en.wikipedia.org/wiki/Alessandro_Voltahttp://www.howstuffworks.com/light-bulb.htmhttp://www.howstuffworks.com/light-bulb.htmhttp://www.howstuffworks.com/motor.htmhttp://www.howstuffworks.com/radio.htmhttp://www.howstuffworks.com/category-automotive.htmhttp://www.howstuffworks.com/pc.htmhttp://www.howstuffworks.com/laptop.htmhttp://www.howstuffworks.com/mp3-player.htmhttp://www.howstuffworks.com/cell-phone.htmhttp://www.howstuffworks.com/cell-phone.htmhttp://en.wikipedia.org/wiki/Electrochemical_cellhttp://en.wikipedia.org/wiki/Voltaic_pilehttp://en.wikipedia.org/wiki/Alessandro_Voltahttp://www.howstuffworks.com/light-bulb.htmhttp://www.howstuffworks.com/light-bulb.htmhttp://www.howstuffworks.com/motor.htmhttp://www.howstuffworks.com/radio.htmhttp://www.howstuffworks.com/category-automotive.htmhttp://www.howstuffworks.com/pc.htmhttp://www.howstuffworks.com/laptop.htmhttp://www.howstuffworks.com/mp3-player.htmhttp://www.howstuffworks.com/cell-phone.htmhttp://www.howstuffworks.com/cell-phone.htm


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As long as the voltage and amps are correct, the DC electricity that comes from one battery is

the same as another. But there are other differences that matter quite a bit, especially weight,

cost, and re-charge cycle. Here's a quick overview of a few common types:

Sealed Lead Acid (SLA) - Heavy, cheap, powerful, reliable, best on a budget

Lithium Ion - Light, Expensive, powerful, reliable, best

money can buy

Nickle Cadmium - These are being phased out. Skip 'em.

Battery Reactions and Chemistry

In any battery, an electrochemical reaction occurs like the ones

described on the previous page. This reaction moves electrons

from one pole to the other. The actual metals and electrolytes

used control the voltage of the battery -- each different reaction

has a characteristic voltage. For example, here's what happens in

one cell of a car's lead-acid battery:

The cell has one plate made of lead and another plate

made of lead dioxide, with a strong sulfuric acid

electrolyte in which the plates are immersed.

Lead combines with SO4 (sulfate) to create PbSO4 (lead sulfate), plus one electron.

Lead dioxide, hydrogen ions and SO4 ions, plus electrons from the lead plate, create

PbSO4 and water on the lead dioxide plate.

As the battery discharges, both plates build up PbSO4 and water builds up in the acid.

The characteristic voltage is about 2 volts per cell, so by combining six cells you get a

12-volt battery.

A lead-acid battery has a nice feature -- the reaction is completely reversible. If you apply

current to the battery at the right voltage, lead and lead dioxide form again on the plates so you

can reuse the battery over and over. In a zinc-carbon battery, there is no easy way to reverse the

reaction because there is no easy way to get hydrogen gas back into the electrolyte.

.


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VOLTS


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CHAIN


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A bicycle chain is aroller chainthat transferspower from thepedalsto the drive-wheelof a

bicycle, thus propelling it. Most bicycle chains are made from plain carbon oralloy steel,

but some are chrome-plated orstainless steel to prevent rust, or simply for aesthetics.

Chain Dimensions

Chain types are identified by number; ie. a number 40 chain. The rightmost digit is 0 for chain of

the standard dimensions; 1 for lightweight chain; and 5 for rollerless bushing chain. The digits to

the left indicate the pitch of the chain in eighths of an inch. For example, a number 40 chain

would have a pitch of four-eighths of an inch, or 1/2", and would be of the standard dimensions

in width, roller diameter, etc.

The roller diameter is "nearest binary fraction" (32nd of an inch) to 5/8ths of the pitch; pindiameter is half of roller diameter. The width of the chain, for "standard" (0 series) chain, is the

nearest binary fraction to 5/8ths of the pitch; for narrow chains (1 series) width is 41% of the

pitch. Sprocket thickness is approximately 85-90% of the roller width.

Plate thickness is 1/8th of the pitch, except "extra-heavy" chain, which is designated by the suffix

H, and is 1/32" thicker.

ANSI Standard Chain DimensionsChain

No.Pitch

Roller

Diameter

Roller

Width

Sprocket

thickness

Working

Load

25 1/4" 0.130" 1/8" 0.110" 140 lbs

35 3/8" 0.200" 3/16" 0.168" 480 lbs

40 1/2" 5/16" 5/16" 0.284" 810 lbs

41 1/2" 0.306" 1/4" 0.227" 500 lbs

50 5/8" 0.400" 3/8" 0.343" 1400 lbs

60 3/4" 15/32" 1/2" 0.459" 1950 lbs
http://en.wikipedia.org/wiki/Roller_chainhttp://en.wikipedia.org/wiki/Roller_chainhttp://en.wikipedia.org/wiki/Roller_chainhttp://en.wikipedia.org/wiki/Power_(physics)http://en.wikipedia.org/wiki/Power_(physics)http://en.wikipedia.org/wiki/Bicycle_pedalhttp://en.wikipedia.org/wiki/Bicycle_pedalhttp://en.wikipedia.org/wiki/Bicycle_pedalhttp://en.wikipedia.org/wiki/Bicycle_wheelhttp://en.wikipedia.org/wiki/Bicycle_wheelhttp://en.wikipedia.org/wiki/Bicyclehttp://en.wikipedia.org/wiki/Steelhttp://en.wikipedia.org/wiki/Alloy_steelhttp://en.wikipedia.org/wiki/Alloy_steelhttp://en.wikipedia.org/wiki/Chrome-platedhttp://en.wikipedia.org/wiki/Stainless_steelhttp://en.wikipedia.org/wiki/Roller_chainhttp://en.wikipedia.org/wiki/Power_(physics)http://en.wikipedia.org/wiki/Bicycle_pedalhttp://en.wikipedia.org/wiki/Bicycle_wheelhttp://en.wikipedia.org/wiki/Bicyclehttp://en.wikipedia.org/wiki/Steelhttp://en.wikipedia.org/wiki/Alloy_steelhttp://en.wikipedia.org/wiki/Chrome-platedhttp://en.wikipedia.org/wiki/Stainless_steel


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80 1" 5/8" 5/8" 0.575" 3300 lbs

Bicycle and Motorcycle Chain Dimensions

Chain No. PitchRoller

Diameter

Roller

Width

Sprocket

thickness

Bicycle, with Derailleur 1/2" 5/16" 1/8" 0.110"

Bicycle, without

Derailleur1/2" 5/16" 3/32" 0.084"

420 1/2" 5/16" 1/4" 0.227"

425 1/2" 5/16" 5/16" 0.284"

428 1/2" 0.335" 5/16" 0.284"

520 5/8" 0.400" 1/4" 0.227"

525 5/8" 0.400" 5/16" 0.284"

530 5/8" 0.400" 3/8" 0.343"

630 3/4" 15/32" 3/8" 0.343"

Selecting a Chain

Two factors determine the selection of a chain; the working load and the rpm of the smallersprocket. The working load sets a lower limit on pitch, and the speed sets an upper limit.

Maximum Pitch = (900 rpm ) 2/3

The smaller the pitch, the less noise, wear, and mechanical losses will be experienced.

Sprockets

There are four types of sprocket;


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Type A: Plain Plate sprockets

Type B: Hub on one side

Type C: Hub on both sides

Type D: Detachable hub

Sprockets should be as large as possible given the application. The larger a sprocket is, the less

the working load for a given amount of transmitted power, allowing the use of a smaller-pitch

chain. However, chain speeds should be kept under 1200 feet per minute.

The dimensions of a sprocket can be calculated as follows, where P is the pitch of the chain, and

N is the number of teeth on the sprocket;

Pitch Diameter = P sin (180 N)

Outside Diameter = P (0.6 + cot ( 180 N) )

Sprocket thickness = 0.93 Roller Width - 0.006"

REGENERATIVE BRAKING IN LATEST CARS


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Regenerative braking can be extremely powerful. According to Craig Van Batenburg, who

teaches Honda and Toyota hybrid service at Automotive Career Development Center in

Worcester, MA, no more than 17 percent of its capability is used in these cars to avoid putting

people into the windshield. Even at that low level of use, in a typical mixture of highway and

around-town driving, regenerative braking can recover about 20 percent of the energy normally

wasted as brake heat. This reduces the drawdown of the battery charge, extends the overall life of

the battery pack and reduces fuel consumption.

Right now, the Honda Insight, Toyota Prius and Honda Civic hybrid, & BMW cars are the only

production cars that use regenerative braking. However, regenerative braking has been used in

trains, elevators and other industrial equipment for almost a century, and it will likely be used on

many more cars and light trucks in the next decade. The technologies for recovering kinetic

energy vary greatly, and some ideas are more promising than others. Heres a look at whats

being seriously developed for automotive use.

In the year2008 BMW is introducing what they call Brake Energy Regeneration on the 5-Series.

The new system uses a larger than normal battery, and an electronically controlled alternator.

The alternator is disengaged from the engine during normal cruise and acceleration and activates

during vehicle deceleration. This adds to the engine drag braking, and the car's kinetic energy is

effectively transformed into electrical energy which replenishes the battery, which now provides

the accessory power.

When the battery level gets too low, the system reverts to normal charging mode. Until BMW

introduces some hybrids in the next couple of years this provides a stop gap that gives an extra

efficiency boost. World Car Fans has an animated video that shows the flow of energy around

the Car In various Operational

WORKING OF REGENERATIVE BRAKING SYSTEM IN

AUTOMOBILES


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Reuse of kinetic energy by using the electric motors to regenerate electricity

Hybrid Synergy Drive can reuse kinetic energy by using its electric motors to regenerate

electricity in what is called "regenerative braking".

Normally, electric motors are turned by passing an electric current through it. However, if some

outside force is used to turn the electric motors, it functions as a generator and produces

electricity. This makes it possible to employ the rotational force of the driving axle to turn the

electric motors, thus regenerating electric energy for storage in the battery and simultaneously

slowing the car with the regenerative resistance of the electric motors.

The system coordinates regenerative braking and the braking operation of the conventional

hydraulic brakes so that kinetic energy, which is normally discarded as friction heat when

braking, can be collected for later reuse in normal driving mode.

Typically, driving in city traffic entails a cycle of acceleration followed by deceleration. The

energy recovery ratio under these driving conditions can therefore be quite high.

To take advantage of this situation, the system proactively uses regenerative braking when

running the car in the low speed range. Taking Prius as an example, the system can save the

energy equivalent of 1 of gas/petrol while running in city traffic for 100 km.

Diagram showing the working of regenerative Braking system in Car


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shown figures are extracted from www.machinenews.com

A regenerative braking system and method for a batteries fuel cell vehicle includes a fuel cell

stack, a plurality of ancillary loads, and a regenerative braking device that is coupled to at least


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one wheel of the vehicle. The regenerative braking device powers ancillary loads when the

vehicle is coasting or braking. The fuel cell powers the loads when the vehicle is accelerating or

at constant velocity. The regenerative braking device dissipates power in an air supply

compressor when the vehicle is traveling downhill to provide brake assistance. The compressor

can be run at high airflow and high pressure to create an artificially high load. A bypass valve is

modulated to adjust the artificially high load of the compressor. A back pressure valve protects

the fuel cell stack from the high airflow and pressure. A controller controls a brake torque of the

regenerative braking device as a function of vehicle speed and modulates the bypass valve.


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BACKGROUND OF THE INVENTION

Fuel cell systems are increasingly being used as a power source in a wide variety of applications.

Fuel cell systems have also been proposed for use in vehicles as a replacement for internal

combustion engines. A solid-polymer-electrolyte fuel cell includes a membrane that is

sandwiched between an anode and a cathode. To produce electricity through an electrochemical

reaction, hydrogen (H.sub.2) is supplied to the anode and oxygen (O.sub.2) is supplied to the

cathode. The source of the hydrogen is typically pure hydrogen, reformed methanol, or other

reformed hydrocarbon fuels.

In a first half-cell reaction, dissociation of the hydrogen (H.sub.2) at the anode generates

hydrogen protons (H.sup.+) and electrons (e.sup.-). The membrane is proton conductive and

dielectric. As a result, the protons are transported through the membrane while the electrons flow

through an electrical load that is connected across the membrane. The electrical load is typically

a motor that drives the wheels of the vehicle or storage batteries. In a second half-cell reaction,

oxygen (O.sub.2) at the cathode reacts with protons (H.sup.+), and electrons (e.sup.-) are taken

up to form water (H.sub.2 O). Therefore, fuel cell vehicles have little or no emissions.

Internal combustion engine vehicles and hybrid vehicles sometimes employ regenerative braking

to improve the efficiency of the vehicle. In non-regenerative braking vehicles, the torque

produced by the brakes causes friction that slows the wheels of the vehicle. The friction creates

waste heat that increases the temperature of the brakes. Regenerative braking devices convert

mechanical brake torque that occurs during vehicle deceleration into power. The energy that is

produced by the brake torque is typically used to recharge a battery pack that powers vehicle

accessory loads such as the lights, radio, pumps, air conditioner, fans, and other devices.

In U.S. a vehicle power system includes an internal combustion engine and a regenerative

braking device that charges a battery pack. The battery pack powers one or more vehicle


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accessories such as vehicle lights, power steering and brake pumps, air conditioner, radiator fan,

water pump, etc. In U.S regenerative braking is used to power a high-voltage, electrically-heated

catalyst that treats the exhaust gas of an internal combustion engine. In U.S. regenerative braking

is used to supply power to increase fuel efficiency and/or to power various electrical loads such

as vehicle accessories.

Regenerative braking is generally provided by a motor/generator that opposes the rotation of the

wheels by applying a negative or regarding torque to the wheels of the vehicle. Because the

negative torque decelerates the vehicle and is often used to assist the brakes, regenerative

braking systems generally reduce the wear on the brakes of the vehicle, which reduces

maintenance costs.

Because fuel cell vehicles are relatively new in the automotive arena, current fuel cells do not produce as much power as internal combustion engines. Fuel cell vehicles are also more

expensive than internal combustion engines. Before widespread acceptance of fuel cells will

occur, these performance and cost issues must be resolved. The performance of the fuel cell is

related to the weight of the fuel cell. Because of the increased weight and cost of battery packs

and DC/DC converters that are required in regenerative braking systems, fuel cell have not

implemented regenerative braking systems.


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SUMMARY OF THE INVENTION

A regenerative braking system and method for a batteriless fuel cell vehicle includes a fuel cell

stack, an ancillary load, and a regenerative braking device that is coupled to at least one wheel of

the vehicle. The regenerative braking device powers the ancillary load when the vehicle is

coasting or braking. The fuel cell powers the ancillary load when the vehicle is accelerating or

at constant velocity.

In other features of the invention, the regenerative braking system includes an air compressor.

The regenerative braking device dissipates power in the air compressor when the vehicle is

traveling downhill to provide brake assistance. A bypass valve has an inlet connected to the air

compressor. When the vehicle is traveling downhill, the air compressor is run at high airflow and

high pressure to create an artificial load. The bypass valve is modulated to adjust the artificial

load of the air compressor.

In still other features of the invention, the regenerative braking device is an electric traction

system. A back pressure valve is connected to a cathode of the fuel cell stack. The back pressure

valve protects the fuel cell stack from the high airflow and pressure. A controller controls a braketorque of the regenerative braking device as a function of vehicle speed and modulates the

bypass valve to vary the artificial load.

Further areas of applicability of the present invention will become apparent from the detailed

description provided hereinafter. It should be understood that the detailed description and

specific examples, while indicating the preferred embodiment of the invention, are intended for

purposes of illustration only and are not intended to limit the scope of the invention.

The regenerative braking device generates power when the vehicle coasts (causing slight

deceleration), is traveling downhill, and/or when the driver applies the brakes (to decelerate the

vehicle). A power distribution device such as a high-voltage bus distributes the power that is

generated by the regenerative braking device. The power distribution device distributes power


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directly to one or more loads and/or recharges the storage battery depending upon the

circumstances.

When the driver depresses the accelerator, an internal combustion engine generates power from

air and fuel that is supplied to the engine. When the vehicle is coasting or braking to reduce

speed, the regenerative braking device generates power that can be used to charge the storage

battery and/or to power the loads. Oftentimes, the storage battery provides power to the

accessories at lower speeds and when the vehicle is stopped to improve fuel efficiency of the

vehicle.

A regenerative braking system for a batteriless fuel cell vehicle. The regenerative braking system

includes a regenerative braking device that is coupled to at least one wheel of the fuel cell

vehicle. The regenerative braking device is preferably an electric traction system. The

regenerative braking system includes a fuel cell stack that includes an anode flowline with an

inlet and an outlet. The fuel cell also includes a cathode flowline with an inlet and outlet.

The regenerative braking system further includes an air compressor, a back pressure valve and a

bypass valve. The bypass valve is connected to an outlet of the air compressor, a cathode of the

fuel cell stack and to the environment. A power output of the regenerative braking device is

connected to a power distribution device that is connected to loads. The loads preferably include

fans, pumps, an air conditioning compressor, heaters, 12 volt battery, and other devices. The

brake torque (and energy) provided by the regenerative braking device is preferably set as a

function of vehicle speed.

The air compressor pressurizes supply air and outputs the pressurized air to the bypass valve. A

controller is connected to the back pressure valve, the bypass value, the compressor, and a

vehicle data bus. The controller modulates the bypass valve to selectively divert the air to the

inlet of the cathode flow line, to exhaust the air and/or to direct the air to another device.

During normal driving when the vehicle's speed is greater than zero and the vehicle is not

accelerating or when the vehicle is at constant velocity, the regenerative braking device produces

power and the loads dissipate the energy. During braking and coasting, air and fuel to the fuel


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cell stack are preferably shut off and no fuel consumption occurs. As a result, the output of the

fuel cell stack is 0 kW during braking and coasting.

When driving downhill (detected by monitoring vehicle acceleration and the position of the

accelerator pedal through the vehicle data bus), the regenerative braking device powers the

ancillary loads. In a highly preferred mode, the controller runs the compressor with high airflow

and high pressure to create an artificial loss. During this condition, the back pressure valve is

either closed or partially opened (if additional power is required from the fuel cell stack). The

controller controls the back pressure valve to prevent the high pressure air that is generated by

the air compressor from reaching the fuel cell stack. The controller modulates the bypass valve to

regulate a compressor load of the air compressor and to regulate the brake torque of the

regenerative braking device.


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RBS IN LOCOMOTIVES

Electric railway vehicle operation

During braking, the traction motor connections are altered to turn them into electrical generators.

The motor fields are connected across the main traction generator (MG) and the motor armatures

are connected across the load. The MG now excites the motor fields. The rolling locomotive

wheels turn the motor armatures, and the motors act as generators. Either sending the generated

current through onboard resistors (dynamic braking) or back into the supply (regenerative

braking) provides the braking load.

For a given direction of travel, current flow through the motor armatures during braking will be

opposite to that during motoring. Therefore, the motor exerts torque in a direction that is

opposite from the rolling direction.

Braking effort is proportional to the product of the magnetic strength of the field windings, times

that of the armature windings.

Regenerative braking utilizes the fact that an electric motor can also act as a generator. The

vehicle's electric traction motor is reconnected as a generator during braking and its output is

connected to an electrical load. It is this load on the motor that provides the braking effect.

An early example of this system was the Energy Regeneration Brake, developed in 1967 for the

Amitron. This was a completely battery powered urban concept car whose batteries were

recharged by regenerative braking, thus increasing the range of the automobile.


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COMPARISON OF DYNAMIC AND REGENERATIVE BRAKES

Dynamic brakes ("Rheostatic brakes" in the UK), unlike Regenerative Brakes, dissipate the

electric energy as heat by passing the current through large banks of variable resistors. Vehicles

that use dynamic brakes include forklifts, Diesel-electric lorcomotives and streetcars. If designed

appropriately, this heat can be used to warm the vehicle interior. If dissipated externally, large

radiator-like cowls are employed to house the resistor banks.

The main disadvantage of regenerative brakes when compared with dynamic brakes is the need

to closely match the generated current with the supply characteristics. With DC supplies, this

requires that the voltage be closely controlled. Only with the development of power electronics

has this been possible with AC supplies, where the supply frequency must also be matched (this

mainly applies to locomotives where an AC supply is rectified for DC motors).

A small number of mountain railways have used 3-phase power supplies and 3-phase induction

motors. This results in a near constant speed for all trains as the motors rotate with the supply

frequency both when motoring and braking.


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DISADVANTAGES

The main disadvantage of regenerative brakes when compared with dynamic brakes is the need

to closely match the electricity generated with the supply. With DC supplies this requires the

voltage to be closely controlled and it is only with the development of power electronics that it

has been possible with AC supplies where the supply frequency must also be matched (this

mainly applies to locomotives where an AC supply is rectified for DC motors).

It is usual for vehicles to include a 'back-up' system such that friction braking is applied

automatically if the connection to the power supply is lost. Also in a DC system or in an AC

system that is not directly grid connected via simple transformers, special provision must also be

made for situations where more power is being generated by braking than is being consumed by

other vehicles on the system.

A small number ofmountain railways have used 3-phasepower supplies and 3-phase induction

motors and have thus a near constant speed for all trains as the motors rotate with the supply

frequency both when giving power or braking.
http://en.wikipedia.org/wiki/Rectifierhttp://en.wikipedia.org/wiki/Mountain_railwayhttp://en.wikipedia.org/wiki/3-phasehttp://en.wikipedia.org/wiki/Induction_motorshttp://en.wikipedia.org/wiki/Induction_motorshttp://en.wikipedia.org/wiki/Rectifierhttp://en.wikipedia.org/wiki/Mountain_railwayhttp://en.wikipedia.org/wiki/3-phasehttp://en.wikipedia.org/wiki/Induction_motorshttp://en.wikipedia.org/wiki/Induction_motors


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DESIGN CONSIDERATIONS

Our project named EBIKE with RBS has following components:

1. Bicycle

2. Dynamo

3. D.C Motor

4. Sprocket

5. Battery

6. Chain

7. Indicator

8. Horn

9. Switches

10. Lamp

Dynamo The placement of the dynamo is done with the rear brake caliper such that

dynamo rubs against the tire sidewall


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D.C Motor - placement of the Propeller motor is done on the rear carrier such that it is

placed directly over and in-line with the main shaft sprocket.


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Sprocket - The Sprocket of same configuration as of the main shaft sprocket is attached to

the DC propeller motor such that a 1:1 drive is made available to the rear wheel.


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Battery - placement of the Sealed Lead-Acid Battery is done on the Frame Inclined Bar

taking special care of its non hindrance in the pedaling or Maneuvering of the bike.

Indicator On the handle bar and carrier


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Horn On the Handle bar

Switches Mounted on Handle Board

Lamp - Mounted in front of Handle

During the Designing Phase of our Project Special considerations were given to the

following points

Minimization of Total Weight of the Product

Minimization of Total cost involved in the Product

Maximization of the Aesthetic Appeal

Maximum comforts as through Ergonomics

Maximization of Performance Delivered


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Components Description

Bicycle Ranger type standard bike

Dynamo 12V, Bottle type

D.C Motor 12V, 180W

Sprocket

Battery 12V, 9Ah, Sealed Lead Acid Battery

Chain

Indicator 12V, flashing type

Horn 12V

Switches 12V

Lamp 12V


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FINDINGS AND CALCULATIONS

RECORDED OBSERVATIONS

The cycle moving at a speed of 18 Km/h (i.e. 5m/s) subjected to different Braking conditions

Braking condition Time taken (s)

Natural Retardation 60

Regenerative Braking 15-20

Friction Braking 5

Regenerative Braking + Friction Braking 3

Top Speed Attained in Assistance with Motor = 25 kmph

Range of bicycle = 10 12 kms

Battery Charging time ( near Discharged condition ) = 2 hrs


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CALCULATIONS

Diameter of Wheel =d = 22 inches = 56cm = 0.56m

Radius of wheel = r = 28 cm = 0.28m

Circumference = 2* *r

= 2*(22/7)*0.28= 1.76m

For calculations the bicycle was tested at a speed of 18 km/h or 5 m\s

Mass of Electric Bicycle = 25 kg *Mass of Rider = 75 kg *

Combined Mass = 100 kg *

*=approx


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Kinetic energy Calculations

Formulas Used

Net K.E. = 0.5* M * v2 + 0.5 * I * 2

I = m * r2

= v/r

Here

M = 100 kg

m = 1.25 kg * 2 = 2.5 kgv = 5m\s

I = m * r2 = 2.5 * (0.28)2 = 0.196 kg msq

= 5/0.28 = 17.90 / s

Hence

Net Kinetic Energy

= 0.5 100 (25) + 0.5 (0.196) (17.90)

= 1250 + 1.72 ( negligible) = 1250 J

Our Studies verify that on an average 40% of this energy is wasted as heat generated on brake

pads due to friction and is a direct loss.

Energy wasted = 1250 * 0.40 = 600 J which is a considerably large amount


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Now with Regenerative Braking

Dynamo Voltage = 12V

Efficiency = = 7 5 %

= current produced

Power dissipated = Heat / time

= 600/5 = 120 W

120 = V * A/

Thus, Possible power Reutilization = 120* = 1200.75 = 90 W


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RESULT

Retardation Rates Braking Distance

Using

friction braking = 1m/s(sq) 12.5m

Regenerative braking = 0.5m/s(sq) 50.0m

Combined Braking = 1.6m/s(sq) 7.5m

Energy

Energy wasted in friction braking= 120 W

Possible power Reutilization = 90 W

Performance

Top Speed Attained in Assistance with Motor = 25 kmph

Range of bicycle = 10 12 kms


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CONCLUSION

The overall goal was to design the Regenerative Braking System while keeping the engineering,

producer and customer models in check. The reason why this feature was used more than all of

the other features are because the other features would not have as much effect on the complete

system. By changing the size and desirable price, weight and capacity can be realized.

We used a survey to find out how the price, weight and capacity were scaled. Much was learned

on how to and not to conduct a survey. A preliminary survey should have been conducted to

determine a realistic value of variables. Also many of choices were not close enough together to

get a reasonable cut off value. Therefore the data that was produced using conjoint analysis was

most likely not as accurate as it could have been.

Future work would consist of a redesign of this model to see exactly how much data we may be

missing with the assumption that we made with low price, weight and capacity. Despite all the

assumptions, we still have realized that this product can be very marketable and that the demand

is extremely large which means this is a viable design that will yield a high return on an

investment.


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FUTURE IMPROVEMENTS, VARIATIONS AND POSSIBILITIES

It's the batteries, This bike is great fun right now but I can see a lot of room for improvement.

Ah, batteries, ever the Achilles' heel of the electric vehicle. Oh how I hate lead acid batteries but

- still stuck with them. NiMH, Lithium Ion, or Nickel Zinc batteries would improve the juice-to-

weight ratio enormously, and would probably double the range, which is the single least

satisfactory thing about this and all electric bikes. The batteries now weigh over 25 pounds and

are the heaviest single component. There are some reasons for hope. The increasing numbers of

hybrid cars are generally using NiMH batteries which should trickle down eventually and be

very suitable for electric bikes. Other battery chemistries as well have made it to market, though

success always seems elusive. The biggest promise right now is that GM and Toyota are really

pushing to put lithium batteries in the next generations of hybrid cars and plug-in hybrids. GM'sChevy Volt, due out by 2010, will only work if they succeed in mass producing lithium ions, and

getting the cost down. It's kind of a chicken and egg problem: huge mass production will bring

the cost down, but until they're cheaper, there isn't enough demand to mass produce them. The

soaring price of motor fuels and the resulting demand for more and better hybrid cars is probably

what will convince manufacturers to bite the bullet and build the factories.

The promise of lithium ion. Certainly the lithium battery has the greatest potential of all the

next-generation chemistries. It has the most energy per pound and is well proven in smaller

applications like cell phones and laptops. A practical battery with this capacity would almost

instantly put battery vehicles on a competitive footing with gasoline powered ones. Current

conventional lithium ions have a serious weakness - they die completely after about 2 to 3 years,

no matter what. But again, if GM and Toyota succeed in getting lithium batteries into hybrids, as

they say they will within the next two years, it will mean that they have largely eliminated or

minimized these drawbacks. Progress with this battery seems to be steady. They are now being

used in some cordless power tools, which use bigger cell sizes and draw heavier loads than

electronic devices. They don't use any heavy metals. There are a number of new types of lithium

cells that don't burst into flames when overheated or pierced. A123 has some of the most

successful new cells, and Toshiba has even demonstrated cells that can be recharged almost fully

in just a few minutes. Chinese cells are now on the market especially for bicycles called


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LiFePo4. These cells are available in a battery pack for small electric vehicles called the Eonyx,

as well as from other packagers. They are still something of an unknown quantity. Once these get

into more people's hands, we will be able to get a reading on their longevity and performance.

Right now they are still about ten or fifteen times as expensive as lead acid batteries.

Well, what about fuel cells? Of course the concept and demonstrations of this still-

experimental technology is very compelling, but there has been so much hype on the subject that

it is still hard to say if this is all just incredibly successful marketing spin by the FC developers. I

also think that in the early 2000's there was an element of clever subterfuge by the auto industry

to take the heat off the fact that average fuel economy in this country was decreasing due to ever

more popular and larger SUVs. It is so much easier and cheaper for an auto company like GM to

run a relatively small early research project on fuel cells, than it is to do serious engineering on

real live production-ready hybrid development. Even in 2006 there are still basically no

economically practical fuel cells in actual use and even their promoters say that any

commercially viable model is at least 5 years off and maybe 10. It is the running joke that the

day of widespread fuel cells and the hydrogen economy always seems to be 20 years off - no

matter when the question is asked. And then, where do we get all the hydrogen? Seems to me

hydrogen is and will remain way more expensive than any petro fuel and I have never seen any

realistic ideas to overcome this problem. And we store it in 10,000 psi cylinders in the trunk? Uh,

OK . . . Believe me I would love to be proved wrong and initially was excited about this

technology like everyone else, but increasingly I am thinking the emperor has no clothes. Maybe

a loincloth.

Motors can still be perfected right? Well, yes and no. is starting to look like a dinosaur, it

could stand to lose some weight. The power is actually about right for a bicycle but just look at

it, it's too big and heavy. There are tons of little scooters out there and it would be possible to get

a 500 watt or 750 watt scooter motor, which is would undoubtedly work well. Currently (July

2009) I see that a 24V Currie 600 watt motor is available for around $130. It is compact and

powerful. The MAC 600W motor might be a better choice but is $279. Try evdeals.com for an

updated motor availability. I would love to get a Lemco pancake motor, www.lemcoltd.com -


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they are light, powerful, and efficient but expensive. This company is now making even smaller

motors that would be perfect for high-powered bikes but $800 for a motor is a bit much.

And of course my whole motorization scheme, with the belt and chain, is not terribly clean or

elegant. I personally thinkthe "hub motor"is the obvious solution for electric bikes, as used on

Lee Iacocca's E-bike and the Wavecrest (which seems to have died and resurrected as the E+)

and others. Heinzmann of Germany seems to still be making a variety of hub motors, as are other

companies. Try Heinzmann's site www.estelle.de for some pretty interesting ideas - I guess they

are now selling bikes, complete kits, motors, batteries and controllers. However, at this point

they are still only about 300 watts = 1/3 HP which is about 1/3 of what they ought to be. Also,

Heinzmann motors tend to be a little noisy and expensive.A hub wheel motor replaces the

normal wheel hub and obviously needs no other transmission, chain, or belt which is a hugesimplification - although of course this can also be a slight drawback in that the gear ratio can't

be changed.

A very popular and reasonably priced hub motor made in China seems to be the Crystalyte,

though I haven't used one myself. There is a similar system sold byWilderness Energy. These

are sold in kits where the hub motor is basically spoked to a bike wheel rim of your choice and

you just replace your old wheel with the motorized one. They tend to go on the front wheel but

can also be installed at the rear. The kits include a pretty slick speed controller, throttle, and

brake-switches to cut the power. Often batteries are a separate purchase. The hubs themselves are

made in various voltages, powers, and rotational speeds to match various wheel sizes and top

speed requirements. This seems to be a decent site with links to dealers in the US and Canada -

www.evsolutions.net.

The gearing, for my use, could certainly benefit from a nice simple transmission. One speed for

the hill and the other for the flat. Electric motors have such great torque throughout the RPM

range that more than two speeds just isn't necessary unless the motor is severely underpowered.

The obvious thing to me would be a hub motor with two or three speeds built in. I have never

seen such a beast.


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I think with better batteries and motor, this bike could easily weigh 25 pounds less or have twice

the range, maybe both. The frame and wheels are no lightweights either, at 36 pounds. That's a

good 10 pounds more than my new mountain bike, and it's got a suspension fork. So in short

with modern components this type of bike could easily weigh less than 50 lbs. Performance

would improve, it would be easier to pedal and you could even carry it on a car roof rack.

How about asolar cell battery charger? They sell these to RV owners. Actually there's no

reason why you couldn't throw a solar cell on your roof and charge the batteries all day. Imagine

- this is real-world fully solar powered transportation, doable today.

As further work on the existing bike, I would love to put a suspension fork on the front and

maybe a suspension seat post. Lights would be nice. At this point this bike would be an amazing

transportation unit by any standards, not just electric vehicles. Also, this starts to become a pretty

intriguing possibility for a trail bike. I used to have dirt bikes but they are dirty and noisy and

environmentally a big problem. A dirt bike is a blast but you're not exactly communing with

nature. A completely silent electric trail bike would be much more like hiking aesthetically, and

would open up long-range trails - can't wait to get some better batteries and go up to the

mountains.

I can also see going to a higher voltage system. 36 or even 48 volts would be a lot better and keepthe current draw down. I started with a 12 V system for simplicity's sake but the power was low

and the current draw was high. I won't go into the basics of electric power except to say that

lower voltage is bad because it leads to higher current which creates more heat and requires a

much bigger motor controller. Controllers are basically sold by amperag

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