TECHNICAL REPORT & SEMINAR ON IC ENGINES In partial fulfillment of the BACHLOR’S DEGREE
in R.T.M. NAGPUR UNIVERSITY, NAGPUR (M.S.) Submitted by: Akshay charde {ME13004} Under the Guidance of Dr. BHASKAR PATEL
DEPARTMENT OF MECHANICAL ENGINEERING KAVIKULGURU INSTITUTE OF TECHNOLOGY & SCIENCE RAMTEK – 441 441 106 (2014-2015) 1
CERTIFICATE This is to certify that this mast. Akshay charde is the bonafide student of third semester mechanical engineering department have successfully successfully completed the technical report & seminar work entitled.
“IC ENGINES”
During the academic year 2014-15 Dr. Bhaskar Patel
Shri. Kolhe Sir
(Project guide)
(Project Co-ordinator) Shri. P.S. PACHPOR H.O.D.
DEPARTMENT OF MECHANICAL ENGINEERING KAVIKULGURU INSTITUTE OF TECHNOLOGY & SCIENCE RAMTEK – 441 441 106 2
ACKNOWLEDGEMENT
I would like to express my gratitude and appreciation to all those who gave me the possibility to complete this report. A special thanks to our third year project guide, DR. Bhaskar Patel , whose helped me through his stimulating suggestions and encouragement, helped me to coordinate my project especially in writing this report. I express our deep sense of gratitude for our project coordinator Shri. Kolhe sir . I thank our head of mechanical engineering department Shri. P.S . Pachpor who gave us inspiration to pursue this report and providing all facilities needed. A special thanks for our beloved principal sir, Dr. Bhaskar Patel , for his encouragement and supporting our ideas in our technical report. I would like to thank our parents, our friends for their help and support. Finally we are also thankful to one and all that directly or indirectly helped us in the successful completion completion of this report.
AKSHAY CHARDE (ME3004)
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INDEX CH.NO. CONTENTS
PAGE NO.
1.
INTRODUCTION
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2.
HISTORY OF IC ENGINES
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3.
TYPES OF IC ENGINES
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4.
OPERATION OF IC ENGINES
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5.
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6.
ADVANTAGES & DISADVANTAGES OF IC ENGINES APPLICATIONS OF IC ENGINES
7.
CONCLUSION
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8.
REFERENCE
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NO. OF FIGURES NO.FIG
1 2 3 4 5 6 7 8
FIGURES IC engine 2 stroke IC engine 4 stroke IC engine 6 stroke IC engine Intake stroke Compression stroke Power stroke Exhaust stroke
Pg.no. 5 9 10 10 12 12 13 13
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CHAPTER-1 INTRODUCTION What are IC engines? IC Engine is the one in which combustion of the fuel takes place in a confined space, producing expanding gases that are used directly to provide mechanical power. po wer. Such engines are classified as reciprocating or rotary, spark ignition or compression ignition, and two-stroke or four-stroke; the most familiar combination, used from automobiles to lawn mowers, is the reciprocating, spark-ignited, four-stroke gasoline engine. Other types of internal-combustion engines include the reaction engine (see jet propulsion, rocket), and the gas turbine. Engines are rated by their maximum horsepower, which is usually reached a little below the speed at which undue mechanical stresses are developed.
Fig.(1) IC engine
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CHAPTER-2 HISTORY The Abbes Hautefeuille described in 1678, an engine for raising water, in which the motive power was obtained by burning gunpowder in a cylinder and cooling the remaining gases with water. The idea was similar to that expressed in the early forms of the steam engine, but Hautefeuille does not appear to have preformed any actual experiments. The same idea was suggested by Huygens in 1680, but experiments made by him and later by Denis Papinwere not attended by success and were abandoned, though they are interesting as representing the first actual attempts at the building of internal-combustion engines. A long period of inaction followed. The discovery of the distillation of gas from coal and the demonstration, by Murdock in 1792, of the application of coal gas for lighting purposes roused new interest in the subject. The introduction of the steam engine for commercial purposes about this time was also a powerful incentive, though for many decades the steam engine was too firmly entrenched and fitted the existing conditions too well to afford much opportunity for competition. About 1791 John Barber explained in a patent how a wheel with vanes could be driven by the released pressure of an orifice close to the vanes. In the century and a quarter that have elapsed since that day, no economical gas turbine has been constructed. Brown ’s Gas Vacuum Engine-
The first internal-combustion engine, according to our modern ideas, was that of Robert Street, patented in England in 1794. In this the bottom of a cylinder was heated by fire and a small quantity of tar or turpentine was projected into the hot part of the cylinder, forming a vapor. The rising of the piston sucked in a quantity of air to form the explosion mixture and also flame for ignition. Wright’s Internal Combustion Engine-
The next engine to attain any considerable prominence was that of Samuel Brown, who secured several patents in England about 1825. Brown’ Brown’s engine consisted of a number of large chambers, in which the hot gases produced by flame were cooled by the injection of water, thus forming a partial vacuum. Th e working pistons, in cylinders adjacent to
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the large chambers, were operated b y atmospheric pressure, all pistons being connected to the same crankshaft. Barnett’s 2-Cycle Engine-
In 1838 William Barnett patented in England an engine which was an advance upon preceding types in that country. It compressed the gas and air separately, igniting the mixture when the piston was at the end of its stroke. The third engine described by this inventor is interesting because it embodies several features of the modern two-cycle engine. The piston moves upward, compressing a mixture of gas and air. Ignition occurs when the piston has reached its highest position, and the piston driven down, expansion occurring until the piston passes the exhaust port at the middle of the cylinder. During the latter half of the stroke the pumps are forcing gas and air into space below the piston, The compression being completed by the working piston and an explosion occurring when the piston reaches its lowest position. Barsanti and Matteucci Engine-
The engine of Barsanti-Matteucci Engine, patented in 1857, illustrates a type of machine that was the first to achieve a real commercial success. Gas and air were exploded under the piston, which was driven upward, finally coming to a rest when all of the work of the explosion had been done. The piston, descending under the pressure of atmosphere, did the work. And thus it worked. Brayton Oil Engine-
To the American the most interesting part of the development of internal-combustion engines is that played by Brayton about 1872 to 1874. The Brayton engine was to some extent the precursor of the present Diesel engine. The mixture of gas and air burned at constant pressure and gave a card resembling somewhat that of the steam engine. This engine was manufactured for a while, but was not able a ble to compete with the Otto-Langen free-piston engine in economy. It was adapted for both gas and petroleum. Early Otto Engine-
The well-known Otto engine was invented by Dr. Nicholas Otto, of Germany, and was patented in this country in 1877. It follows the cycle that has been described by Beau de Rochas , 7
now known as the four-cycle, or sometimes as the Otto cycle. The engine was first known as the Otto-Silent, to distinguish it from the free-piston engine, which was rather noisy. It immediately established the internal-combustion engine on a firm footing, and the engines of the four-cycle type sold today show merely minor improvements. The sliding valve on 1876 has been replaced by poppet pop pet valves, v alves, and the flame ignition has been b een replaced by b y the electric spark. Otherwise, the Otto cycle of 1876 has persisted p ersisted and at this time thousands of them are bei ng manufactured. The development of the Diesel engine for oil began about 1894. As has been stated, this engine is similar to the Brayton. Air is compressed to about 500 pounds pressure and oil is sprayed into this highly compressed air. It burns spontaneously at nearly constant pressure, which is followed by a long expansion. The extremely high temperature of the air previous to the injection of the fuel, and the high temperature maintained during this injection, together with the long expansion, give the engine the highest efficiency of any thermal motor. The development of the Diesel engine has been so recent that it is not necessary to elaborate upon it. At this time, it is being manufactured manu factured in all of the European countries and in America, and there is a tendency on the part of many of the American manufacturers who are bringing out new engines to adopt the features of the Diesel. The gas turbine is as yet in the experimental stage. A number have been built and are of course, extremely interesting. The T he success of the steam turbine has encouraged many to believe that the gas turbine will achieve similar success. Nothing of recent development can be said to encourage this view. The difficulties in the way of successful gas turbines are very great, and while some turbines have been designed and run, none of them has shown an efficiency at all comparable to that of ordinary four-cycle engines.
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CHAPTER-3 TYPES OF IC ENGINES
Internal combustion engines can be classified b y their configuration.
1) Two-stroke engine A two-stroke, or two-cycle ,engine is a type t ype of internal combustion engine which movements. This is accomplished by the end of the combustion stroke and the beginning of the compression stroke happening simultaneously and performing the intake and exhaust functions at the same time. Two-stroke engines often provide h igh power-to-weight ratio, usually in a narrow range of rotational speeds called the “ power band” band”. They have a greatly reduced number of moving parts, are more compact and significantly lighter.
Fig.(2) Two stroke engine cycle.
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2) Four-stroke engine A four-stroke engine (also known as four-cycle) is an internal combustion engine in which the piston completes four separate strokes which comprise a single thermodynamic cycle. A stroke refers to the full travel of the piston alon g the cylinder, in either direction.
Fig.(3) four stroke engine cycle
3) Six-stroke engine The pistons in six-stroke engine go up and down three times for each injection of fuel. There are two power strokes: one with fuel, the other with steam or air. The second approach app roach , called the opposed piston design , uses a second opposed piston in each cylinder that moves at half the cyclical rate of the main piston, thus giving six piston movements per cycle. Functionally, the second piston replaces the valve mechanism of a conventional engine but also increases the compression ratio.
Fig.(4) six cycle engine cycle
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CHAPTER-4 OPERATION AND WORKING OF IC ENGINES
Principle of working of an IC Engine:
Air-fuel mixture in the combustion chamber (inside the cylinder) is ignited, either by a spark plug (in case of Spark S park Ignition Engines) or by compression (in case o f Compression Ignition engines). This ignition produces tremendous amount of h eat and pressure inside the cylinder. This induces reciprocating motion in the piston. Power of the piston is transmitted to a crankshaft which undergoes rotary motion. The rotary motion is ultimately transmitted to the wheels of the vehicle, via a transmission system, to produce propulsion in the vehicle. As the combustion takes place internally inside the c ylinder (a part of working fluid circuit), the engine is called internal combustion engine.
Four-stroke internal combustion engines have four basic steps that repeat with every two revolutions of the engine: (1) Intake/suction stroke (2) Compression stroke (3) Power/expansion stroke (4) Exhaust stroke
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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) creating a drop in pressure. The inlet v alve opens as a result of the cam lobe pressing down on the valve stem, and the vaporized fuel mixture is sucked into the combustion chamber. The inlet valve closes at the end of this stroke.
Fig.(5) Intake 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.
Fig.(6) compression stroke
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3.Powerstroke:
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 center. This expansion of gases caused by ignition of the fuel produces the power that is transmitted to the crank shaft mechanism.
Fig.(7) power stroke 4.Exhauststroke:
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.
Fig.(8) Exhaust stroke. Four-stroke engines require two revolutions. Many engines overlap these steps in time; turbine engines do all steps simultaneously at different parts of the en gines.
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CHAPTER-5 ADVANTAGES AND DISADVANTAGES OF IC ENGINES
The main advantages of an internal combustion engine are given below: Multi fuel capacity Flexibility and reliability Easy starting and control Waste heat recovery Less noise and vibrations
The disadvantages of an internal combustion engine are given below: Poor fuel economy Stability Part load efficiency High combustion rates Reduction gearing is required
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CHAPTER-6 APPLICATIONS OF IC ENGINES Internal combustion engine, a type of heat engine mostly refers to reciprocating engine. Fuel mixture and air is burnt in very small and confined space by combustion. Exothermic reaction results in increase of pressure and temperature. Internal combustion engine is capable of converting chemical fuel energy in to mechanical energy. Depending on the application type, internal combustion engine are designed. Internal combustion engine finds its own major application in mobile propulsion system. The use of engine in mobile state of affairs ensures more power to weight ratio in addition to excess fuel energy density. Internal combustion engine is now widely used in number of automobiles, aircraft vehicles, motorbikes, boats and other similar locomotives. Automobiles such as helicopters, big barges and ships and jet crafts utilize excess power which is supplied in the form of gas turbines. Gas turbines are especially used in major power plants and similar naval applications. It is also used for minor power applications. Competitive technology of electric motor invention is used in power automobiles such as low power automobiles and non automobiles. Battery operated electric vehicles have hybrid internal combustion engine technology. Batteries are made of Lithium ion and Lithium poly chemistry and are of safe, cost efficient and has increased life expectance. Compression ratio can be varied depending dependin g on the operation o peration principle like temperature, fuel type and equivalence equ ivalence ratio rat io of internal combustion engine. If one of the parameter is altered as desired, then compression ratio of interest is obtained. The mechanical friction between crankshaft and connecting rod is negligible. Use of piston dynamics improves the quality of engine oil and emissions such as NOx.
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CHAPTER-7 CONCLUSION
The internal combustion engines plays vital role in the working of an automobile. The history behind the invention of ic engine is well considered. Classification of ic engines depending upon number of strokes is also studied. studied. The 4-stroke working of an engine is fully fully explained. Benefits as well as the limitations of this technology are observed. The applications of this technology in modern vehicles are also taken into consideration. Thus the technical study on the topic has been successful.
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REFERENCES BOOKS-
-Introduction to IC Engines By Richard stone
th
Tata McGraw-hill Education 9 edition
pg.no. 365
-Internal Combustion Engine fundamentals By- john Heywood
th
Laxmi publication 11 edition
pg.no. 193
-I.C. Engines By- Ganesan
th
Published by SAE international 9 edition pg.no. 383
WEBLINKS-
http://en.wikipedia.org/wiki/Internal_combustion_engine&sa http://www.infoplease.com/encyclopedia/science/ http://www.brighthube//engineering.com/machine-design/ http://archive.org/stream/internalcombusti00carprich/
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