air engine report

Department of Mechanical Engineering, University of Petroleum & Energy Studies, Dehradun

Modification In a Single Cylinder 4 Stroke Engine For Using Compressed

Air As A Fuel

Submitted by:Abhisar MehraAnkita Sehgal

Bhartendu PalniKavita WaldiaOjas Chopra

Supervisor: Dr. B.R.Singh Assistant director

University Of Petroleum & Energy Studies

2011-2012

Modification In A Single Cylinder 4-Stroke Engine For Using Compressed Air As Fuel

CERTIFICATE

This is to certify that the project work on “ Modification of a single

cylinder 4 stroke engine for compressed air “ submitted to the

University of Petroleum & Energy Studies, Dehradun, by Abhisar

Mehra(R16020001) , Ankita Sehgal(R160209005) , Bhartendu

palni(R160209013) , Kavita Waldia(R160209029), Ojas

Chopra(R160209043 ), as minor project in Automotive Design

Engineering during Academic session 2011-2012 is a bonafide work

carried out by him under my supervision and guidance.

Signature of Project Guide:

Name: Mr G G Sastry

Designation: Assistant Professor

Mechanical Department

UPES


Modification In A Single Cylinder 4-Stroke Engine For Using Compressed Air As Fuelii


Declaration

Modification of a single cylinder 4 stroke engine for compressed air

The Project Dissertation is submitted in partial fulfilment of academic requirements for

B.tech-Automotive Design Engineering( V and VI sem). This minor project is a result

of our own investigation. All sections of the text and results, which has been obtained

from other sources, are fully referenced. We understand that cheating and plagiarism

constitute a breach of University regulations and will be dealt with accordingly.

Signature:Signature:

Name of the Student:Name of the Student: Abhisar Mehra.Abhisar Mehra.

Ankita Sehgal. Ankita Sehgal.

Bhartendu Palni. Bhartendu Palni.

Kavita Waldia. Kavita Waldia.

Ojas Chopra. Ojas Chopra.

Date:Date: 1515thth May 2012 May 2012

Modification In A Single Cylinder 4-Stroke Engine For Using Compressed Air As Fueliii


Acknowledgement

The project bears the imprints of the efforts extended by many people to whom we are

deeply indebted.

We would like to thank our mentor Prof. G.G.Sastry under whose valuable guidance we

gained the insights and ideas without which the project could not have seen the light of

the day. His suggestions have been valuable and his teachings during the course of our

discussions would continue to be a guiding principle in our works in the future as well.

We would also like to thank the HOD of Mechanical Department Dr. Mukesh Saxena,

Our Course co-coordinator Prof. Ajay Kumar, Activity Coordinator Prof. Deepak

Bharadwaj for their constant support and guidance.

We would also like to thank Automotive lab assistant Mr. Gupta for his support during

testing of the project.

Finally, we would like to thank the whole Mechanical Engineering Department –

COES for providing us an opportunity to make use of our technical knowledge and

materialize in the form of this project.

Modification In A Single Cylinder 4-Stroke Engine For Using Compressed Air As Fueliv


Abstract

A Compressed-Air Engine is an air engine, using compressed air, which is stored in a

tank. Instead of mixing fuel with air and burning it in the engine to drive pistons with hot

expanding gases, compressed-air engine use the expansion of compressed air to drive

their pistons. The project has been chosen in order to check the feasibility of compressed

air engine and to compare it with the conventional I.C engine.

An existing 4 stroke-cycle gasoline engine has been partially modified without

dynamically changing its mechanism for the purpose to utilize compressed air as an

alternative energy source. The principle is to mechanically control the compressed air

flow through the intake and exhaust valves every revolution of the crankshaft by

modifying the camshaft cam's lobes, which changes the engine operation from 4 strokes

to 2 strokes cycle mode.

As gasoline and other major fuels used now a days in I.C engines releases unburnt gases

in the environment and are counted in the major sources of pollution, compressed air

engine can be used for cleaner, pollution free travel. Overall, air engine does not appear to

offer any advantage over purely electrical means of storing energy .As long as there are

no substantial innovations in compressed-air technology, the real progress in this sector

may be the emphasis on light materials and small car design.

Modification In A Single Cylinder 4-Stroke Engine For Using Compressed Air As Fuelv

http://en.wikipedia.org/wiki/Free_expansion

http://en.wikipedia.org/wiki/Compressed_air

http://en.wikipedia.org/wiki/Air_engine


Table of Contents

A typical Table of Contents page looks like this

Certificate……………………………………………………………(ii)

Declaration……………………………………………………….....(iii)

Acknowledgement…………………………………………………..(iv)

Abstract …………………………………………………..…………(v)

Table of Contents………………………………………….………. (vi)

Chapter-1: Introduction…………………………………………….. 7

Chapter-2: Literature Review............................................................ 11

Chapter-3: Problem Definition.......................................................... 20

Chapter-4: Model Construction and Solution................................... 21

Chapter-5: Discussion of Results and Validation............................. 27

Chapter-6: Conclusions and Recommendations for future work...... 30

References......................................................................................... 32

Modification In A Single Cylinder 4-Stroke Engine For Using Compressed Air As Fuelvi


1 – Introduction

A four-stroke engine, also known as four-cycle, is an internal combustion engine in which

the piston completes four separate strokes—intake, compression, power, and exhaust -

during two separate revolutions of the engine's crankshaft. The cycle begins TDC, when

the piston is farthest away from the axis of the crankshaft. A cycle refers to the full travel

of the piston from TDC to BDC.

INTAKE stroke: on the intake or induction stroke of the piston, the piston descends from

the top of the cylinder to the bottom of the cylinder, reducing the pressure inside the

cylinder. A mixture of fuel and air, or just air in a diesel engine, is forced by atmospheric

(or greater) pressure into the cylinder through the intake port. The intake valve then close.

COMPRESSION stroke: with both intake and exhaust valves closed, the piston returns

to the top of the cylinder compressing the air, or fuel-air mixture into the combustion

chamber of the cylinder head.

POWER stroke: this is the start of the second revolution of the engine. While the piston

is close to Top Dead Centre, the compressed air–fuel mixture in a gasoline engine is

ignited, usually by a spark plug, or fuel is injected into the diesel engine, which ignites

due to the heat generated in the air during the compression stroke. The resulting pressure

from the combustion of the compressed fuel-air mixture forces the piston back down

toward bottom dead centre.

EXHAUST stroke: during the exhaust stroke, the piston once again returns to top dead centre while the exhaust valve is open. This action evacuates the burnt products of combustion from the cylinder by expelling the spent fuel-air mixture out through the exhaust valve(s).

Power output limitations

Modification In A Single Cylinder 4-Stroke Engine For Using Compressed Air As Fuel

http://en.wikipedia.org/wiki/Combustion_chamber

http://en.wikipedia.org/wiki/Combustion_chamber

http://en.wikipedia.org/wiki/Poppet_valve

http://en.wikipedia.org/wiki/Crankshaft

http://en.wikipedia.org/wiki/Crankshaft

http://en.wikipedia.org/wiki/Piston

http://en.wikipedia.org/wiki/Internal_combustion_engine


The maximum amount of power generated by an engine is determined by the maximum amount of air ingested. The amount of power generated by a piston engine is related to its size (cylinder volume), whether it is a two-stroke or four-stroke design, volumetric efficiency, losses, air-to-fuel ratio, the calorific value of the fuel, oxygen content of the air and speed (RPM). The speed is ultimately limited by material strength and lubrication.

Types of engine Various types of engine used depending on the number of cylinders:

Flat: The cylinder lies flat. Half of the cylinders are located on one side of the crankshaft and the other half on other side. This makes a car more stable due to lower centre of gravity.

Inline: Inline have cylinders on top of the crankshaft. They stand in line at a vertical 90 degrees. Inline engines can run smooth and provide a lot of power.

V – Type: The cylinders are located on opposite side of the crankshaft and are elevated up a varying amount of degrees depending on the manufacturer.

W – type: W –type work well for a large number of cylinders because everything become more compact and shorter. These are found in few cars.

SINGLE CYLINDER:

A single-cylinder engine is a basic piston engine configuration of an internal combustion engine. It is often seen on motorcycles, auto rickshaws, motor scooters, mopeds and has many uses in portable tools and garden machinery. It has been used in automobiles and tractors.

Single-cylinder engines are simple and compact, and will often deliver the maximum power possible within a given envelope. Single-cylinder engines are simple and economical in construction. The vibration they generate is acceptable in many applications, while less acceptable in others. The bestselling motor vehicle of the world, the Honda Super Cub, has a very fuel-efficient 49 cc single-cylinder engine and big-diameter 17-inch wheels.

POLLUTION CAUSED BY I.C ENGINE AND THEIR ENVIRONMENTAL IMPACT

All the I.C. engine when they operate pollute the environment through hot combustion gases. The automotive vehicle and industrial power unit using internal combustion engine are major contributors to this problem.

Modification In A Single Cylinder 4-Stroke Engine For Using Compressed Air As Fuel8

http://en.wikipedia.org/wiki/Honda_Super_Cub

http://en.wikipedia.org/wiki/Power_(physics)

http://en.wikipedia.org/wiki/Tractor

http://en.wikipedia.org/wiki/Automobile

http://en.wikipedia.org/wiki/Garden_tool

http://en.wikipedia.org/wiki/Motor_scooter

http://en.wikipedia.org/wiki/Auto_rickshaw

http://en.wikipedia.org/wiki/Motorcycle



http://en.wikipedia.org/wiki/Reciprocating_engine

http://en.wikipedia.org/wiki/Volumetric_efficiency

http://en.wikipedia.org/wiki/Volumetric_efficiency

http://en.wikipedia.org/wiki/Two-stroke


The following products are usually considered as pollutants.

a) Carbon monoxide: Carbon monoxide is generally formed when the mixture is rich in fuel. The amount of carbon monoxide formed increased as the mixture becomes more and richer in fuel.

b) Nitric Oxide: The rate of formation of nitric oxide is higher with rich mixture than with lean mixture. Nitric oxide does not decompose sufficient during expansion.

c) Hydrocarbons: Complex chain of hydrocarbons result in polymerization and agglomeration during combustion and some of hydrocarbon escape into exhaust due to imperfect combustion.

d) Smoke or particulate: Particulate matter (matters which cause visible smoky exhaust) generally occurs in liquid or solid form

e) Sulphur Oxide: The oxides of sulphur are formed during combustion. These oxides are harmful for the engine itself as well as general industry and life.

Transportation activities are a dominant factor behind the emission of most

pollutants and thus their impacts on the environment. These impacts, like all

environmental impacts, can fall within three categories:

Direct impacts. The immediate consequence of transport activities on the environment where the cause and effect relationship is generally clear and well understood.

Indirect impacts. The secondary (or tertiary) effects of transport activities on environmental systems. They are often of higher consequence than direct impacts, but the involved relationships are often misunderstood and difficult to establish.

Cumulative impacts. The additive, multiplicative or synergetic consequences of transport activities. They take into account of the varied effects of direct and indirect impacts on an ecosystem, which are often unpredicted.

FUELS:

Conventional fuels include: fossil fuels (petroleum (oil), coal, propane, and natural gas).


http://en.wikipedia.org/wiki/Natural_gas

http://en.wikipedia.org/wiki/Propane

http://en.wikipedia.org/wiki/Coal

http://en.wikipedia.org/wiki/Petroleum

http://en.wikipedia.org/wiki/Fossil_fuels

http://people.hofstra.edu/geotrans/eng/ch8en/conc8en/tenvitbl.html


Alternative fuels, known as non-conventional or advanced fuels, are any materials or substances that can be used as fuels, other than conventional fuels. alternative fuels include biodiesel, bioalcohol (methanol, ethanol,butanol), chemically stored electricity (batteries and fuel cells), hydrogen, non-fossil methane, non-fossil natural gas, vegetable oil, and other biomass sources.

From the last two decade lot of researches are being made to tap down air freely available in atmosphere at high compression, which can easily be stored in cylinders with little modified design. . Thus efficiency of IC engine gets improved and without all running four stroke cycle it runs two stroke cycles. Guy Nigre-a French scientist developed the engine and claims that it is zero Pollution and given demonstration in Aug.’2004.Similarly, Quasiturbine is also developed to run on radial cycle where all four strokes take place in one complete 360 degree. A compressed air quasi turbine car was demonstrated in Oct’2004. These engines are basically running with use of compressed air and gas.

.


http://en.wikipedia.org/wiki/Biomass

http://en.wikipedia.org/wiki/Vegetable_oil_used_as_fuel

http://en.wikipedia.org/wiki/Natural_gas

http://en.wikipedia.org/wiki/Methane

http://en.wikipedia.org/wiki/Hydrogen

http://en.wikipedia.org/wiki/Fuel_cell

http://en.wikipedia.org/wiki/Electricity

http://en.wikipedia.org/wiki/N-Butanol

http://en.wikipedia.org/wiki/Ethanol

http://en.wikipedia.org/wiki/Methanol

http://en.wikipedia.org/wiki/Bioalcohol

http://en.wikipedia.org/wiki/Biodiesel

http://en.wikipedia.org/wiki/Fuel


http://en.wikipedia.org/wiki/Chemical_substance

http://en.wikipedia.org/wiki/Material



2 – Literature Review

In the project, running of a single cylinder 4 stroke engine by a compressed gas, one of the basic requirement was to modify a 4 stroke engine in such a way that instead of mixing fuel with air and burning it in the engine to drive pistons with hot expanding gases; it will use the expansion of compressed air to move the piston. In it there is no combustion engine therefore no pollution in exhaust. Whereas in Internal combustion engines such as reciprocating internal combustion engines produce air pollution emissions, due to incomplete combustion of carbonaceous fuel. The main derivatives of the process are carbon dioxide , water and some soot — also called particulate matter . The effects of inhaling particulate matter have been studied in humans and animals and include asthma, lung cancer, cardiovascular issues, and premature death. There are, however, some additional products of the combustion process that include nitrogen oxides and sulphur and some uncombusted hydrocarbons, depending on the operating conditions and the fuel-air ratio. PM, carbon



monoxide, sulphur dioxide, and ozone, are regulated as criteria air pollutants under the Clean Air Act to levels at which human health and welfare are protected. Other pollutants, such as benzene and butadiene, are regulated as hazardous air pollutants whose emissions must be lowered as much as possible depending on technological and practical considerations. Significant contributions to noise pollution are made by internal combustion engines. Automobile and truck traffic operating on highways and street systems produce noise. Noise pollution is excessive, displeasing human, animal, or machine-created environmental noise that disrupts the activity or balance of human or animal life.

But this all has not stop the Automotive production down the ages and the requirements of wide range of energy-conversion systems. These include electric, steam, solar, turbine, rotary, and different types of piston-type internal combustion engines. The reciprocating-piston internal -combustion system, operating on a four-stroke cycle, has been the most successful for automobiles, while diesel engines are widely used for trucks and buses. The gasoline engine was originally selected for the automobile due to its flexibility over a wide range of speeds. Also, the power developed for a given weight engine was reasonable; it could be produced by economical mass-production methods; and it used a readily available, moderately priced fuel--gasoline. Reliability, compact size, and range of operation later became important factors.

The engine are classified based on combustion (ignition), fuel used, cooling, application and construction. Based on the combustion type: 1. External combustion engines 2. Internal combustion engines.Based on fuel used : 1. Diesel engines 2. Petrol engines 3. CNG engines and LPG engines.Based on cooling system : 1. Air cooled engines 2. Liquid cooled engines Based on applications : 1. Statinary engine 2. Rocket engine 3. Automobile engine Based on construction : 1. Inline engines 2. Opposed engines 3. Rotary engine



4. V-engines 5. W engines

At present the most used in engine in vehicles are internal combustion engine the internal combustion engine is an engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber. In an internal combustion engine, the expansion of the high-temperature and high -pressure gases produced by combustion apply direct force to some component of the engine. This force is applied typically to pistons. This force moves the piston over a distance, transforming chemical energy into useful mechanical energy. he term internal combustion engine usually refers to an engine in which combustion is intermittent, such as the more familiar four-stroke and two-stroke piston engines, along with variants, such as the six-stroke piston engine . A second class of internal combustion engines use continuous combustion: gas turbines, jet engines and most rocket engines, each of which are internal combustion engines on the same principle as previously described. The internal combustion engine is quite different from external combustion engines, such as steam or Stirling engines, in which the energy is delivered to a working fluid not consisting of, mixed with, or contaminated by combustion products. Working fluids can be air, hot water, pressurized water or even liquid sodium, heated in some kind of boiler.

As their name implies, four-stroke internal combustion engines have four basic steps that repeat with every two revolutions of the engine are as follows:

(1) Intake stroke (2) Compression stroke (3) Power stroke and (4) Exhaust stroke

1.Intake stroke: The first stroke of the internal combustion engine is also known as the suction stroke because the piston moves to the maximum volume position (downward direction in the cylinder). The inlet valve opens as a result of the cam lobe pressing down on the valve stem, and the vaporized fuel mixture enters the combustion chamber. The inlet valve closes at the end of this stroke.

2. Compression stroke: In this stroke, both valves are closed and the piston starts its movement to the minimum volume position (upward direction in the cylinder) and compresses the fuel mixture. During the compression process, pressure, temperature and the density of the fuel mixture increases.



3. A Power stroke: When the piston reaches a point just before top dead center, the spark plug ignites the fuel mixture. The point at which the fuel ignites varies by engine; typically it is about 10 degrees before top dead centre. This expansion of gases caused by ignition of the fuel produces the power that is transmitted to the crank shaft mechanism.

4. Exhaust stroke: In the end of the power stroke, the exhaust valve opens. During this stroke, the piston starts its movement in the maximum volume position. The open exhaust valve allows the exhaust gases to escape the cylinder. At the end of this stroke, the exhaust valve closes, the inlet valve opens, and the sequence repeats in the next cycle. Four-stroke engines require two revolutions.

Internal combustion engines require ignition of the mixture, either by spark ignition (gasoline)(SI) or compression ignition(diesel) (CI)

Gasoline Ignition Process

Gasoline engine ignition systems generally rely on a combination of a lead–acid battery and an induction coil to provide a high-voltage electric spark to ignite the air-fuel mix in the engine's cylinders. This battery is recharged during operation using an electricity-generating device such as an alternator or generator driven by the engine. Gasoline engines take in a mixture of air and gasoline and compress it to not more than 12.8 bar (1.28 MPa), then use a spark plug to ignite the mixture when it is compressed by the piston head in each cylinder.

Diesel Ignition Process

Diesel engines, rely solely on heat and pressure created by the engine in its compression process for ignition. The compression level that occurs is usually twice or more than a gasoline engine. Diesel engines take in air only, and shortly before peak compression,



spray a small quantity of diesel fuel into the cylinder via a fuel injector that allows the fuel to instantly ignite.

But in today’s world, there has been a growing emphasis on the pollution producing features of automotive power systems. This has created new interest in alternate power sources and internal-combustion engine refinements that were not economically feasible in prior years. Although a few limited-production battery-powered electric vehicles have appeared from time to time, they have not proved to be competitive owing to costs and operating characteristics. However, the gasoline engine, with its new emission-control devices to improve emission performance, has not yet been challenged significantly. An approach to build an engine running on compressed air is also a new technology and research on it is still on.

Air is compressed by an air compressor. An air compressor is a device that converts power (usually from an electric motor, a diesel engine or a gasoline engine) into kinetic energy by compressing and pressurizing air, which, on command, can be released in quick bursts. There are numerous methods of air compression, divided into either positive-displacement or negative-displacement types.

The three basic types of air compressors are

reciprocating rotary screw rotary centrifugal

These types are further specified by:

the number of compression stages cooling method (air, water, oil) drive method (motor, engine, steam, other) lubrication (oil, Oil-Free where Oil Free means no lubricating oil contacts the

compressed air) packaged or custom-built



Reciprocating Air Compressors

Reciprocating air compressors are positive displacement machines, meaning that they increase the pressure of the air by reducing its volume. This means they are taking in successive volumes of air which is confined within a closed space and elevating this air to a higher pressure. The reciprocating air compressor accomplishes this by a piston within a cylinder as the compressing and displacing element.

Single-stage and two-stage reciprocating compressors are commercially available.

Single-stage compressors are generally used for pressures in the range of 4 bar to 6 bar.

Two-stage compressors are generally used for higher pressures in the range of 6 bar to 17 bar.

The reciprocating air compressor is single acting when the compressing is accomplished using only one side of the piston. A compressor using both sides of the piston is considered double acting. Load reduction is achieved by unloading individual cylinders. Typically this is accomplished by throttling the suction pressure to the cylinder or bypassing air either within or outside the compressor. Capacity control is achieved by varying speed in engine-driven units through fuel flow control. Reciprocating air compressors are available either as air-cooled or water-cooled in lubricated and non-lubricated configurations and provide a wide range of pressure and capacity selections.

Rotary Screw Compressor Rotary air compressors are positive displacement compressors. The most common rotary air compressor is the single stage helical or spiral lobe oil flooded screw air compressor. These compressors consist of two rotors within a casing where the rotors compress the air internally. There are no valves. These units are basically oil cooled (with air cooled or water cooled oil coolers) where the oil seals the internal clearances. Since the cooling takes place right inside the compressor, the working parts never experience extreme operating temperatures. The rotary compressor, therefore, is a continuous duty, air cooled or water cooled compressor package. Rotary screw air compressors are easy to maintain and operate. Capacity control for these compressors is accomplished by variable speed and variable compressor displacement. For the latter control technique, a slide valve is positioned in the casing. As the compressor capacity is reduced, the slide valve opens, bypassing a portion of the compressed air back to the suction. Advantages of the rotary



screw compressor include smooth, pulse-free air output in a compact size with high output volume over a long life.The oil free rotary screw air compressor utilizes specially designed air ends to compress air without oil in the compression chamber yielding true oil free air. Oil free rotary screw air compressors are available air cooled and water cooled and provide the same flexibility as oil flooded rotaries when oil free air is required.

Centrifugal Compressors

The centrifugal air compressor is a dynamic compressor which depends on transfer of energy from a rotating impeller to the air.Centrifugal compressors produce high-pressure discharge by converting angular momentum imparted by the rotating impeller (dynamic displacement). In order to do this efficiently, centrifugal compressors rotate at higher speeds than the other types of compressors. These types of compressors are also designed for higher capacity because flow through the compressor is continuous. Adjusting the inlet guide vanes is the most common method to control capacity of a centrifugal compressor. By closing the guide vanes, volumetric flows and capacity are reduced. The centrifugal air compressor is an oil free compressor by design. The oil lubricated running gear is separated from the air by shaft seals and atmospheric vents.

Positive-displacement air compressors work by forcing air into a chamber whose volume is reduced to compress the air. Piston-type air compressors use this principle by pumping air into an air chamber through the use of the constant motion of pistons. They use unidirectional valves to guide air into a chamber, where the air is compressed. Rotary screw compressors also use positive-displacement compression by matching two helical screws that, when turned, guide air into a chamber, the volume of which is reduced as the screws turn. Vane compressors use a slotted rotor with varied blade placement to guide air into a chamber and compress the volume.

Negative-displacement air compressors include centrifugal compressors. These devices use centrifugal force generated by a spinning impeller to accelerate and then decelerate captured air, which pressurizes it.

Conventional air compressors are used in several different applications:

To supply high-pressure clean air to fill gas cylinders



To supply moderate-pressure clean air to a submerged surface supplied diver To supply moderate-pressure clean air for driving some office and school

building pneumatic HVAC control system valves To supply a large amount of moderate-pressure air to power pneumatic tools For filling tires To produce large volumes of moderate-pressure air for macroscopic industrial

processes (such as oxidation for petroleum coking or cement plant bag house purge systems).

Most air compressors either are reciprocating piston type, rotary vane or rotary screw. Centrifugal compressors are common in very large applications. There are two main types of air compressor's pumps: Oil lubed and oil-less. The oil-less system has more technical development, but they are more expensive, louder and last for less time than the oiled lube pumps. However, the air delivered has better quality.

Compressed air has a low energy density. In 300 bar containers, about 0.1 MJ/L and 0.1 MJ/kg is achievable, comparable to the values of electrochemical lead-acid batteries. While batteries can somewhat maintain their voltage throughout their discharge and chemical fuel tanks provide the same power densities from the first to the last litre, the pressure of compressed air tanks falls as air is drawn off. A

consumer-automobile of conventional size and shape typically consumes 0.3-0.5 kWh (1.1-1.8 MJ) at the drive shaft per mile of use, though unconventional sizes may perform with significantly less.

Like other non-combustion energy storage technologies, an air vehicle displaces the emission source from the vehicle's tail pipe to the central electrical generating plant. Where emissions-free sources are available, net production of pollutants can be reduced. Emission control measures at a central generating plant may be more effective and less costly than treating the emissions of widely dispersed vehicles.Since the compressed air is filtered to protect the compressor machinery, the air discharged has less suspended dust in it, though there may be carry-over of lubricants used in the engine.



Compressed-air vehicles are comparable in many ways to electric vehicles, but use compressed air to store the energy instead of batteries. Their potential advantages over other vehicles include:

Much like electrical vehicles, air powered vehicles would ultimately be powered through the electrical grid. Which makes it easier to focus on reducing pollution from one source, as opposed to the millions of vehicles on the road.

Transportation of the fuel would not be required due to drawing power off the electrical grid. This presents significant cost benefits. Pollution created during fuel transportation would be eliminated.

Compressed-air technology reduces the cost of vehicle production by about 20%, because there is no need to build a cooling system, fuel tank, Ignition Systems or silencers.

Air, on its own, is non-flammable. The engine can be massively reduced in size. The engine runs on cold or warm air, so can be made of lower strength light

weight material such as aluminium, plastic, low friction teflon or a combination.

Compressed-air tanks can be disposed of or recycled with less pollution than batteries.

Compressed-air vehicles are unconstrained by the degradation problems associated with current battery systems.

The air tank may be refilled more often and in less time than batteries can be recharged, with re-filling rates comparable to liquid fuels.

Lighter vehicles cause less damage to roads, resulting in lower maintenance cost.

The price of filling air powered vehicles is significantly cheaper than petrol, diesel or biofuel. If electricity is cheap, then compressing air will also be relatively cheap.



3 – Problem Definition

The objective of the project is the use of compressed air as a source of fuel in IC engines.

For this modifications in the engine are needed. The engine is a conventional four stroke

single cylinder IC engine of the HERO HONDA CD 100.

The increasing level of pollutants in the environment and the inflating prices of petrol and

diesel form the basis of study of various sources of alternative fuels. The investigation

and study of an unconventional source of fuel carried out to establish its advantages and

limitations over gasoline and to determine its application.

A four stroke single cylinder IC engine HERO HONDA CD 100 is identified. The

modification of four stroke engine is required to get greater power output when using

compressed air. The gear ratio between gears of camshaft and crankshaft requires change

from 2:1 to 1:1. The performance was measured using an air compressor with air being

supplied to the engine from the inlet.



4 – Model Construction and Solution

The four-stroke engine used is a Radical Aluminium Combustion Engine (R.A.C.E.). Since the engine block and the piston are made up of aluminium alloys; there is less wear and tear on the engine. Furthermore, the clearance between the piston and the cylinder liner can be kept very close, thus avoiding damage both to the piston and the cylinder liner.

The Engine that was undertaken to work upon had the following Technical Specifications:

Technical SpecificationsEngine : Four stroke, Air cooled, Single CylinderEngine Displacement : 97ccMax Power : 7.02 HP@8500 rpm Ignition : ElectronicDry Weight : 12kgsBore : 50mmStroke: 50.6mmFuel consumption: 87kmpl (Highway data)



The basic process that was followed:

DATA COLLECTION

LITREATURE REVIEW

ROUGH SCHEMATICS

DIFFICULTIES/PROBLEMS

FACED

SOLUTIONS PROPOSED

DESIGN ANALYSIS

ENGINE TESTING

The design was Layout for the Engine modification by discussion among the team

members and the assigned mentor and then certain parameters were felt to be materialised

and finally the Engine modification was done to use compressed air as a fuel.

Modifications Implemented:



Our design is very simple involving no complexities. The project would be using a 4-

stroke engine and would supply the compressed air from the input valve as in a

conventional engine.

Compressed air is less dense than the combustible mixture so we would be supplying a

minimum pressure of 1bar to the piston which will help drive the piston from TDC to

BDC and back again TDC through the flywheel inertia and thus the engine will work and

deliver power to a measurable extent.

The 4stroke engine was modified to work under 2cycles of operation instead of 4cycles in

order to deliver greater power output while using compressed air as a fuel.

Thus the following modifications were necessary to be implemented:

1. Gear of Camshaft and Crankshaft were installed of same size, so as to minimise the 4cycles operation to a 2cycle operation.



2. The Camshaft was fabricated with two cams opposite to each other, i.e. The Cam now has two Rise Period.

Formulas & Calculations:

1. For power calculations: P= 2πNT/4500

2. For mean effective pressure: M.E.P = (6x10^4 x B.P)/(L x A x N x K)

Where, B.P= Brake Power

L = Stroke length

A = Bore Diameter

N = Engine RPM

K = No. of Cylinders



3. For air displaced by compressor: Volume of air = (Engine RPM x Engine displacement)/1728

4. For power consumed by compressor: P = 202xVxln(Delivery P/Inlet P)Where, V= Vol. Displaced Delivery P = delivery pressure Inlet P = inlet pressure

Bore diameter ¿ π x 0.502 = 19.6cm2

Initial pressure taken = 1bar = 1kg/cm2

So, Force on Piston = Pressure x Area

= 1kg/cm2 x 19.6cm2



= 19.6kgf

Force component acting along Connecting rod = 19.6kgf x cos10

= 19.33kgf

Therefore, Torque on Crankshaft = Force x crank radii

= 19.33kgf x 0.025m

= 0.483kg-m

Thus By using the above calculations, pressure which was applied, i.e. up to 6bar, the

above parameters are calculated and thus the Maximum Torque obtained on crankshaft at

6bar pressure = 2.895kg-m.



5 – Validation and Discussion of Results

RESULTS OBTAINED:

After fabrication & Testing of the engine, the following Results were obtained and

respective graphs were drawn out of the tested data which was

1. Graph showing the Pressure supplied Vs. Engine RPM characteristics

0 1 2 3 4 5 6 70

100

200

300

400

500

600

700

800

900

1000

Pressure vs R.P.M.

Pressure (bar)

R.P.

M



2. Graph depicting the Pressure supplied and Torque output on the Crankshaft

relation

0 1 2 3 4 5 6 70

0.5

1

1.5

2

2.5

3

3.5

Pressure vs Torque

Pressure (bar)

Torq

ue o

n cr

anks

haft

(kg-

m)

3. The gasoline engine torque curve for the RPM under which the engine was tested can

be shown by:

100 200 300 400 500 600 700 800 900 1000 11000

0.05

0.1

0.15

0.2

0.25

RPM vs Torque for Gasoline Engine

R.P.M.

Torq

ue (k

gf m

)



The engine torque curve for the compressed air engine dominates the torque curve of

gasoline engine at low speeds, i.e. up to 1000RPM, but as the load on the Engine

increases and the RPM gets higher, the Gasoline engine provides more torque than the

engine which uses compressed air as fuel.

Thus for low speed applications, the compressed air engine is suitable and can work

efficiently.

4. The Combination of the first two in a single Graph for easy comparison:

0 1 2 3 4 5 6 70

100

200

300

400

500

600

700

800

900

1000

0

0.5

1

1.5

2

2.5

3

3.5

0.403

0.965000000000001

1.447

1.93

2.412

2.895

228

369

521

619

749

879

RPM vs Pressure vs Torque

RPMTorque

Pressure (bar)

RPM



The Objective was Verified as well as Validated during the testing of the as the Engine

ran successfully on the different Pressure supplied by the Compressor present in the ADE

lab.



6 – Conclusions and Recommendations for future work

Based on the work that has been done on this project, following conclusion has been

drawn:-

The engine used in the project is being subjected to modifications like,1. Cam-shaft modification- A new cam was fabricated with a profile such that for one cycle of piston movement inlet and outlet valve opens and closes as required.2. New set of gears for camshaft and crankshaft-This was done so that cam does not rotate once in two revolutions of crankshaft.

Besides the advantages discussed earlier the project has the following limitations: Like the modern car and most household appliances, the principal

disadvantage is the indirect use of energy. Energy is used to compress air, which - in turn - provides the energy to run the motor. Any conversion of energy between forms results in loss. For conventional combustion motor cars, the energy is lost when oil is converted to usable fuel - including drilling, refinement, labour, storage, eventually transportation to the end-user. For compressed-air cars, energy is lost when electrical energy is converted to compressed air.

Tanks get very hot when filled rapidly. SCUBA tanks are sometimes immersed in water to cool them down when they are being filled. That would not be possible with tanks in a car and thus it would either take a long time to fill the tanks, or they would have to take less than a full charge, since heat drives up the pressure

Early tests have demonstrated the limited storage capacity of the tanks; the only published test of a vehicle running on compressed air alone was limited to a range of 7.22 km.

A 2005 study demonstrated that cars running on lithium-ion batteries out-perform both compressed-air and fuel cell vehicles more than threefold at same speeds.



After working on the project for two semesters the following inferences were drawn:

As gasoline and other major fuels used presently in Internal combustion engines releases unburnt gasses in the environment and are counted in the major sources of pollution , air propelled engine can be used as cleaner , pollution free source of energy or small distance travel.

It can be used as a power source in industries where diesel or gasoline engine can be costlier issue, or to reduce pollution. On river banks to collect water, power pneumatic systems, etc.

As it is an air propelled engine, so it needs a constant supply of compressed air continuously for uninterrupted working.

Again, if used in vehicles for short distance travelling vehicles, it cannot provide much speed to the vehicle as for that a higher air-pressure would be needed which would further increase the size of compressed air cylinder and thus weight of the vehicle.



References

1. www.tramwayinfo.com/tramways/Articles/ Compair2.htm accessed 23 June 2009

2. "The Air Car". theaircar.com. http://www.the aircar.com/acf/air-cars/the air car.html. Retrieved 2008-09-12.

3. V.Ganesan , I.C. Engines(2006), New Delhi, Tata McGraw Hill publishing co.

4. Planet Mechanics - Air Propelled Sandwich Part , National Geographic channel

5. www.theaircar.com/acf/air-cars/energy-storage.html. Retrieved 2008-09-16

6. Videos on Air Propelled Engines ,www.youtube.com

7. www.carazoo.com/autonews/0109200801/Tatas-Air- Car--launch


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