Diesel Internal Combustion Engines-sem3 Parts

7/21/2019 Diesel Internal Combustion Engines-sem3 Parts

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Internal CombustionInternal CombustionEnginesEngines



ObjectivesObjectives

• Uses for internal combustion engines

• Components and purposes of each

• Operation of systems

• Two stroke engines

•

Four stroke engines



tructural Componentstructural Components

• Cylinder !lock• "art of engine frame

that contains

cylinders in whichpiston moves

• upports liners #

head



tructural Componentstructural Components

• Cylinder $ead%&ssembly• erves to admit' confine' and release

fuel%air

• Cover to cylinder block• upports valve train

• Crankcase• Engine frame section that houses the

crankshaft

• Oil sump• (eservoir for collecting and holding lube oil



)oving Components)oving Components

• Three *roups + according to motion

• (eciprocating only ,pistons and

valves-• (eciprocation # rotary ,connecting

rods-

• (otary only ,crankshafts andcamshafts-



)oving Components)oving Components• "iston

• &cted on by combustion gases

• .ightweight but strong%durable

• "iston (ings• Transfer heat from piston to

cylinder • eal cylinder # distribute lube oil

• "iston "in• "ivot point connecting piston to

connecting rod• Connecting (od

• Connects piston # crankshaft

• reciprocating rotating motion




• Crankshaft• Combines work done by each piston• /rives camshafts' generator' pumps' etc0

•

Flywheel• &bsorbs and releases kinetic energy ofpiston strokes ' smoothes rotation ofcrankshaft






• 1alves• Intake2 open to admit air to

cylinder E3haust2 open to

allow gases to be rejected

• Camshaft # Cams• Used to time the addition of

intake and e3haust valves

• Operates valves via

pushrods # rocker arms



OperationOperation

• Increased pressure of combustion

gases acts on piston ' converted to

rotary motion• Can be 4 or 5 stroke engines

• 46stroke2 7 power stroke per 7

crankshaft rev• 56stroke2 7 power stroke per 4

crankshaft rev



OperationOperation• Engine stroke

• & stroke is a single traverse of the cylinder by

the piston ,from T/C to !/C-

• 7 revolution of crankshaft 8 4 strokes of piston



Four6troke /iesel EngineFour6troke /iesel Engine

• Intake stroke• Intake valve open' e3haust valve shut

• "iston travels from T/C to !/C

• &ir drawn in

• Compression stroke• Intake and e3haust valves shut

• "iston travels from !/C to T/C

• Temperature and pressure of air

increase




• "ower stroke• Intake and e3haust valves shut• Fuel injected into cylinder and ignites• "iston forced from T/C to !/C

• E3haust stroke• Intake valve shut' e3haust valve open• "iston moves from !/C to T/C• Combustion gases e3pelled




• trokes

• Intake

• Compression

• "ower

• E3haust



Two6troke /iesel EngineTwo6troke /iesel Engine

• 7 power stroke every crankshaft revolution,vice every two w% 56stroke-

• Uses pressuri9ed air to simultaneously

supply new air and e3pel combustiongases

• cavenging• E3haust valve open' inlet port e3posed

• "ressuri9ed air enters' e3pels combustiongases

• "iston near !/C




• Compression• Intake and e3haust valves shut

• "iston travels from !/C to T/C

• Temperature and pressure of air increase

• "ower stroke• Intake and e3haust valves shut

•

Fuel injected into cylinder and ignites• "iston forced from T/C to !/C




• trokes

• Compression

• "ower



46T(O:E # 56T(O:E46T(O:E # 56T(O:E

• Two6stroke advantages• $igher power to weight ratio

• .ess complicated valve train

• Four6stroke advantages• )ore efficient burning process

• &s si9e increases' power6to6weight ratio

improves



upporting ystemsupporting ystems

• &ir system• upplies # removes air%gases

•

&ir supplied at constant pressure byblower%compressor

• Fuel ystem• Fuel Injection high pressure pumps

• Fuel injector2 sprays fuel in ,more

efficient)



upporting ystemsupporting ystems

• Ignition system• /iesel has compression ignition

• *asoline has spark plugs

• Cooling system• Uses fresh water and%or salt water to cool

• .ubrication system

• "rovide lubrication and cooling• /rive Train + /irect or Indirect

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Diesel Internal Combustion Engines-sem3 Parts