TITLE PAGE NO.ABSTRACT 1INTRODUCTION 2 to 3CLASSIFICATION 4 to 5APPLICATION OF IC ENGINE

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WORKING PRINCIPLE OF IC ENGINE

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FOUR –STROKE PETROL ENGINE OR FOUR STROKE SPARK ENGINE(IC ENGINE)

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BACKGROUND 12IC ENGINE TERMINOLOGY

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IC ENGINE COMPONENTS

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ENGINE DESIGN 23SUMMARY 24 to 27REFERENCES&WEB RESOURCES 28

S.N1.2.3.4.

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7.8.9.10.11.12.

Internal-combustion engine, one in which combustion of the fuel takes place in a confined space, producing expanding gases that are used directly to provide mechanical power. 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.

ABSTRACT

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INTRODUCTIONInvented in early 1680First attempt by Christian HuygensConverts heat energy produced by burning

of fuel to mechanical output.Basically consists of a piston-cylinder

arrangement.The expansion of air due to the heat

produced moves the piston inside the cylinder.

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The first two stroke engine design was a diesel engine by Dugald Clark in 1878, and used a similar cylinder heat to a four –stroke diesel engine, and a supercharger.

The gasoline two stroke engine, and the cylinder parts on which it depends were invented by Joseph Day in 1889. These cylinder parts were subsequently incorporated into diesel two-stroke engines, replacing either just inlet valves or both inlet and exhaust valves.

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1. According to thermodynamic cycle i) Otto cycle engine or Constant volume heat supplied cycle. ii) Diesel cycle engine or Constant pressure heat supplied

cycle iii) Dual-combustion cycle engine2. According to the fuel used: i) Petrol engine ii) Diesel engine iii) Gas engine3. According to the cycle of operation: i) Two stroke cycle engine ii) Four stroke cycle engine4. According to the method of ignition: i) Spark ignition (S.I) engine ii) Compression ignition (C I )

engine

CLASSIFICATION

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5. According to the number of cylinders.i) Single cylinder engine ii) Multi cylinder engine6. According to the arrangement of cylinder:I) Horizontal engine ii) Vertical engine iii) V-

enginev) In-line engine vi) Radial engine, etc.7. According to the method of cooling the

cylinder:I) Air cooled engine ii) Water cooled engine8. According to their applications:i) Stationary engine ii) Automobile engine iii)

Aero engineiv) Locomotive engine v) Marine engine, etc.

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APPLICATION OF IC ENGINE

The internal combustion engine is an engine in which the combustion of fuel-oxidizer mixture occurs in a confined space

applied in: automotive rail transportation power generation ships aviation garden appliances 6VIKASH

WORKING PRINCIPLE OF IC ENGINEIn internal combustion engine combustion of fuel takes place inside theengine cylinder. Power is generatedintermittently (only during power stroke)and flywheel is used to provide uniformoutput torque. Usually these engines arereciprocating engines. The reciprocatingengine mechanism consists of pistonwhich moves in a cylinder and forms amovable gas tight seal. By means of aconnecting rod and a crank shaftarrangement, the reciprocating motion ofpiston is converted into a rotary motion ofthe crankshaft. They are most popularbecause of their use as main prime mover in commercial vehicles.

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The four-stroke cycle petrol engines operateon Otto (constant volume) cycle shown inFigure 3.0. Since ignition in these engines isdue to a spark, they are also called sparkignition engines. The four different strokesare:i) Suction strokeii) Compression strokeiii) Working or power or expansion strokeiv) Exhaust stroke.

Four-Stroke Petrol Engine OR Four stroke Spark Ignition Engine (S.I. engine)

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Suction Stroke : During suction stroke, the piston is moved from the top dead centre to the bottom dead centre by the crank shaft. The crank shaft is revolved either by the momentum of the flywheel or by the electric starting motor. The inlet valve remains open and the exhaust valve is closed during this stroke. The proportionate air-petrol mixture is sucked into the cylinder due to the downward movement of the piston.• Compression Stroke: During compression stroke, the piston moves from bottom dead centre to the top dead centre, thus compressing air petrol mixture. Due to compression, the pressure and temperature are increased Just before the end of this stroke the spark – plug initiates a spark, which ignites the mixture and combustion takes place at constant volume.

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• Working Stroke: The expansion of hot gases exerts a pressure on the piston. Due to this pressure, the piston moves from top dead centre to bottom dead centre and thus the work is obtained in this stroke. Both the inlet and exhaust valves remain closed during this stroke.

Exhaust Stroke: During this stroke, the inlet valve remains closed and the exhaust valve opens. The greater part of the burnt gases escapes because of their own expansion. The piston moves from bottom dead centre to top dead centre and pushes the remaining gases to the atmosphere. When the piston reaches the top dead centre the exhaust

valve closes and cycle is completed. The operations are repeated over and over again in running the engine. Thus a four stroke engine completes one working cycle, during this the crank rotate by two revolutions.

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Four Stroke Engine How it Works.mp4

BACKGROUNDSince the two stroke engine fires on every

revolution of the crankshaft, a two stroke engine is usually more powerful than a four stroke engine of equivalent size. This, coupled with their lighter, simpler construction makes two stroke engines popular in chainsaws, line trimmers, outboard motors, snowmobiles, jet-skis, light motor cycles, and model airplanes.

Unfortunately most two strokes engines are inefficient and are terrible polluters due to the amount of unspent fuel that escapes through the exhaust port. 1

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ENGINE TERMINOLOGY

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IC ENGINE - TERMINOLOGY

• Top Dead Center (TDC): Position of the piston when it stops at the furthest point away from the crankshaft.

– Top because this position is at the top of the engines (not always), and dead because the piston stops as this point. Because in some engines TDC is not at the top of the

engines(e.g: horizontally opposed engines, radial engines, etc,.) Some sources call this position Head End Dead Center (HEDC).

– Some source call this point TOP Center (TC).– When the piston is at TDC, the volume in the

cylinder is a minimum called the clearance volume.

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• Bottom Dead Center (BDC): Position of the piston when it stops at the point closest to the crankshaft.– Some sources call this Crank End Dead Center

(CEDC) because it is not always at the bottom of the engine. Some source call this point Bottom Center (BC).

• Stroke : Distance traveled by the piston from one extreme position to the other : TDC to BDC or BDC to TDC.

• Bore :It is defined as cylinder diameter or piston face diameter; piston face diameter is same as cylinder diameter( minus small clearance).

• Swept volume/Displacement volume : Volume displaced by the piston as it travels through one stroke.– Swept volume is defined as stroke times bore.– Displacement can be given for one cylinder or

entire engine (one cylinder times number of cylinders).

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• Clearance volume : It is the minimum volume of the cylinder available for the charge (air or air fuel mixture) when the piston reaches at its outermost point (top dead center or outer dead center) during compression stroke of the cycle. – Minimum volume of combustion

chamber with piston at TDC.• Compression ratio : The ratio of total

volume to clearance volume of the cylinder is the compression ratio of the engine.– Typically compression ratio for SI

engines varies form 8 to 12 and for CI engines it varies from 12 to 24

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Figure2: Engine components 18VIKASH

INTERNAL COMBUSTION ENGINE COMPONENTS: I.C. Engine components shown in figure1 and figure2 are

defined as follows: • Block : Body of the engine containing cylinders, made of

cast iron or aluminium.• Cylinder : The circular cylinders in the engine block in

which the pistons reciprocate back and forth.• Head : The piece which closes the end of the cylinders,

usually containing part of the clearance volume of the combustion chamber.

• Combustion chamber: The end of the cylinder between the head and the piston face where combustion occurs.– The size of combustion chamber continuously changes from

minimum volume when the piston is at TDC to a maximum volume when the piston at BDC.

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• Crankshaft : Rotating shaft through which engine work output is supplied to external systems.

– The crankshaft is connected to the engine block with the main bearings.

– It is rotated by the reciprocating pistons through the connecting rods connected to the crankshaft, offset from the axis of rotation. This offset is sometimes called crank throw or crank radius.

• Connecting rod : Rod connecting the piston with the rotating crankshaft, usually made of steel or alloy forging in most engines but may be aluminum in some small engines.

• Piston rings: Metal rings that fit into circumferential grooves around the piston and form a sliding surface against the cylinder walls.

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• Camshaft : Rotating shaft used to push open valves at the proper time in the engine cycle, either directly or through mechanical or hydraulic linkage (push rods, rocker arms, tappets) .

• Crankcase : Part of the engine block surrounding the crankshaft.– In many engines the oil pan makes

up part of the crankcase housing.• Exhaust manifold : Piping system which

carries exhaust gases away from the engine cylinders, usually made of cast iron .

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• Intake manifold :Piping system which delivers incoming air to the cylinders, usually made of cast metal, plastic, or composite material.– In most SI engines, fuel is added to the

air in the intake manifold system either by fuel injectors or with a carburetor.

– The individual pipe to a single cylinder is called runner.

• Spark plug : Electrical device used to initiate combustion in an SI engine by creating high voltage discharge across an electrode gap.

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ENGINE DESIGN

Inline Engine

V Type Engine

Flat Engine

Radial Engine

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Each downward stroke of the piston is a power stroke

Each upward stroke of the piston is a compression stroke

The intake and exhaust cycle may be considered a part of the power and compression stroke and begins after completion of the power stroke as the exhaust valves open.

The intake and exhaust cycle ends after the piston closes off the intake ports of the cylinder liner on the compression stroke.

CONCLUSION

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Greater mechanical simplicity.Higher power output per unit weight because of absence of auxiliary units like boiler , condenser and

feed pumpLow initial costHigher brake thermal efficiency as only a small fraction of heat energy of the fuel is dissipated to cooling systemThese units are compact and requires less spaceEasy starting from cold conditions

ADVANTAGE OF IC ENGINE

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I C engines cannot use solid fuels which are cheaper. Only liquid or gaseous fuel of given specification can be efficiently used. These fuels are relatively more expensive.

I C engines have reciprocating parts and hence balancing of them is problem and they are also susceptible to mechanical vibrations.

DISADVANTAGE OF IC ENGINE

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FUTURE OF IC ENGINES-new direction

New technologies are needed to improve efficiency of gasoline and diesels.

• Engines need to be optimized to balance emissions, fuel cost, and market competitiveness.

• Development of predictive models for engine physical processes has been an additional enabling factor for advanced concepts in engine design.

• New low temperature combustion (LTC) concepts, such as: Homogeneous Charge Compression Ignition (HCCI), Premixed Charge Compression Ignition (PCCI) and Reactivity Controlled Compression Ignition (RCCI), …….

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• Crouse WH, and Anglin DL, (1985),

(Automotive Engine), Tata McGraw Hill.P.K NAG (Tata McGraw Hill)Heisler H, (1999), Vehicle and engine Technology, Arnold

REFERENCES

www.wikipedia.comwww.eng.fsu.eduwww.slideshare.comwww.mne.psu.edu/simpson/cources

WEB RESOURSES

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