ic engines - abstracted

8/12/2019 IC Engines - abstracted

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IC ENGINES


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1. Basics

2. Classification

3. Terminology

4. Components


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Basics Combustion Engines Chemical energy in fuel converted to thermal energy by

combustion or o idation !eat engine converts chemical energy into mechanical energy Thermal energy raises temperature and pressure of gases "ithin

engine# and gas e pands against mechanical mechanisms ofengine

Combustion $nternal% fuel is burned "ithin the engine properly &including e.g.

roc'et engines# (et engines) E ternal% combustion is e ternal to the engine &e.g. steam# *tirling

engine)


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Jetengine

Stirlingengine

Steamengine

Gas

Turbine


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1. Basics

2. Classification

3. Terminology

4. Components


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Classification of $C engines $gnition +umber of stro'es ,alve location

-esign osition and number of cylinders /ir inta'e 0uel input method 0uel used Cooling /pplication


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$gnition Spark ignition &*$)% high voltage electrical discharge bet"een t"o

electrodes ignites air fuel mi ture in combustion chambersurrounding spar' plug# etrol Engine Compression ignition &C$)% air fuel mi ture self ignites due to high

temperature in combustion chamber caused by high compression#-iesel engine

+o. of stro'es

0our stro'e % four piston movements over t"oengine revolutions for each engine cycle T"o stro'e % t"o piston movements over one

revolution for each engine cycle


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,alve location ,alves in head ,alves in bloc' ne valve in head and one in bloc' &less common)-esign

eciprocatingo Engine has one or more cylinders in "hich pistonsreciprocate bac' forth

o Combustion chamber in closed end of the cylindero o"er delivered to rotating output cran'shaft by mechanical

lin'age "ith pistons otary

o Engine made of bloc' built around large nonconcentric rotor cran'shaft

o

Combustion chambers are built into the non rotatingbloc'


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Reciprocating engine

Rotaryengine


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osition +o. of Cylinders *ingle cylinder &e.g. la"nmo"ers) $n line or straight% cylinders in straight line# one behind the other

in length of cran'shaft ,% t"o ban's of cylinders at an angle "ith each other along a

single cran'shaft# angle typically 56 768 0lat or opposed cylinder &, "ith 1968)% t"o ban's of cylinders

opposite each other on a single cran'shaft &small aircrafts) :% three ban's of cylinders on same cran'shaft &not common) pposed piston engine% t"o pistons in each cylinder# combustion

chamber bet"een pistons adial engine% cylinders positioned radially around cran'shaft


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Inline engineV engine

Flat/opposed cylinderengine


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W engine

pposed piston engine Radial engine


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Superc!arged

Turboc!arged


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0uel input method Carburated % air fuel mi ed at throat Fuel injection

;ultipoint ort 0uel $n(ection % one or more in(ectors ateach cylinder inta'e

Throttle Body 0uel $n(ection % in(ectors upstream ofinta'e manifold

Cooling /ir cooled


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0uel used >asoline -iesel or fuel oil >as &natural gas or methane) )% mainly propane#

propylene# butane and butylene /lcohol &ethyl# methyl) -ual fuel &e.g. methane?diesel) >asohol &e.g. 76@ gasoline# 16@ alcohol) Biodiesel % cleaner burning diesel fuel made from

natural# rene"able sources such as vegetableoils


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1. Basics

2. Classification

3. Terminology

4. Components


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Terminology TDC % top dead center# piston position farthest from

cran'shaft BDC % bottom dead center# piston position nearest to

cran'shaft Direct fuel injection % into main combustion chamber

Indirect fuel injection % into a secondary chamber Bore % diameter of cylinder or piston face Stroke % distance that piston moves Clearance volume % volume in combustion chamber at T-C Displacement volume % volume displaced by piston Ignition delay % Time bet"een start of ignition and start of

combustion


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Terminology &Contd.) Air-fuel ratio % atio of mass flo" rate of air to

that of fuel Specific fuel consumption % fuel used per unit

po"er

missions % + # C # !C# solids


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1. Basics

2. Classification

3. Terminology

4. Components


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Components of an engine


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Components Block % body of engine containing cylinders Bearing % main bearing for cran'shaft Cams!aft % rotating shaft used to push open valves at the

proper time in engine cycle Carburetor % ,enturi flo" device to dra" fuel and mi "ith

air Catalytic converter % reduces emissions by chemical

reaction Combustion c!amber % volume bet"een cylinder head

and piston face Connecting rod % connects piston "ith cran'shaft Crankcase % part of engine bloc' surrounding cran'shaft Cranks!aft % rotating shaft through "hich engine "or'

output is supplied to e ternal systems# rotated byreciprocating pistons through connecting rods


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Components &Contd.) "!aust manifold % piping "hich carries e haust gases

a"ay from engine cylinders Fan % to increase air flo" through radiator Fly#!eel % to smoothen engine rotation Fuel injector % pressuriAed noAAle to in(ect fuel into air or

cylinder Fuel pump % to move fuel from tan' to engine $lo# plug % electrical resistance inside combustion

chamber to help cold start %ead % piece "hich closes end of cylinders %ead gasket % sealant bet"een engine bloc' and head Intake manifold % piping "hich delivers incoming air to

cylinders &il pan % oil reservoir on bottom of engine bloc'# part of

the cran'case


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Components &Contd.) il pump % to distribute oil from sump il sump % reservoir for the oil system of the engine iston rings % metal rings around piston to seal gap

bet"een piston and cylinder ush rods % lin'age bet"een camshaft and valves on

!, engines adiator % li=uid to air heat e changer to cool engine od bearing % rod connecting the piston "ith the rotating

cran'shaft *par' plug % creates high voltage discharge across an

electrode gap *peed control cruise control % control system *tarter % hand starter# electric motor# or small $C engines

for large $C engines


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Components &Contd.) Superc!arger % compressor po"ered from cran'shaft to

compress incoming air T!rottle % butterfly valve at upstream end of inta'e

manifold to control air flo" rate into *$ engine Turboc!arger % turbine compressor po"ered by e haust

flo" to compress incoming air 'alves % controls flo" of air in and out of the cylinders (ater jacket % li=uid flo" passages around cylinder for

cooling (ater pump % to circulate coolant

ic engines - abstracted

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