diesel 4s engine model (1)

8/2/2019 Diesel 4S Engine Model (1)

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Diesel Engine 4 Stroke Cycle

modelDirect Injection

Load Diesel 4S cycle.ppt as well and then run this presentation in

Slide Show mode to see the Animated sequence at the end


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4 STROKE DIESEL ENGINEGeoff. Bootle.

GTC UK 2009

DirectInjection

This is a simplified model of a single cylinder Diesel engine to show theprincipal parts, their relationships to each other and how the engine works.

Is not based on any real engine, but is generally representative of realengines. Most real engines are made up of several of this unit sharing a singleflywheel and cam shaft drive e.g. Three, four and six cylinder engines.

Many minor details and some components are left out for clarity, for example

the bearings, exhaust pipe silencer, air intake filter and the fuel injection pump.


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Moving parts

Bolts and fixingsomitted for clarity

Cam Shaft Drive. The cam-shaft drive arrangement is simplyrepresented by a box. In reality there would be a chain drive or a

gear train between the crank-shaft and the cam-shafts.

Inside the solid body ofthe Engine are a number

of fast moving parts

THE CONSTRUCTION OF THE ENGINE

Crank-shaft

Cam-shafts


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The Names of the Main Moving partsPiston

Connecting Rod

GudgeonPin

Crank-Shaft

Cam-Shafts

Valves

Fly-

Wheel

PistonRing

Valve Spring

Bolts and fixingsomitted for clarity


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Some stationary parts

Engine block

CylinderHead

FuelInjectorCylinder

Head Cover

Timing Case

Sump

(holds lubricating oil)Bolts and fixings areomitted for clarity


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The Piston Rings fit ingrooves on the

Piston. They seal thePiston to be gas tight

in the Cylinder of theBlock

Cylinder, alarge roundhole boredstraight and

parallel throughthe Block

Block, a large stronglump of metal that isthe main structural

member of the engine

Piston, a cylindrical part made tobe a close, but free running, fit in

the Cylinder of the Block.

Cylinder Head, Cylinder and Piston

The Cylinder Head sits on the top of theBlock to close off the top of the Cylinder.It also carries the Valves, Fuel Injector

and the Inlet and Exhaust passages

Bolts and fixings areomitted for clarity


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The Connecting Rod is inserted into a large recessin the bottom of the Piston

The Piston is attached to swivel on the little end of

the Connecting Rod by the Gudgeon Pin through the

side of the Piston.

The Big end of Connecting Rod fits onto the throw

of the Crank Shaft. (this end is usually split in half and boltedtogether for assembly purposes)

The Connecting Rod connects the linear up and

down motion of the Piston within the Cylinder with

the circular rotary motion of the Crank Shaft.

The Fly-Wheel is attached to the end of the Crank-Shaft and serves to store the pulses of energy fromthe Power Strokes, delivering energy to the other 3strokes, and power to whatever the engine is driving.

Piston

Gudgeon pin

Crank Shaft

Connecting Rod

Little End

Big End

Throw

PISTON, CRANK SHAFT & FLY-WHEEL

Fly-Wheel


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One set of a Cam and a Valve controls the Inlet flow of fresh air into the Cylinder.The other set controls the burnt Exhaust Gases out of the Cylinder. Both theseValves are spring loaded to shut and seal the Cylinder during the Compression and

Power strokes. They open into the Cylinder, so that they are held closed by the highpressures during the Compression and Power strokes.

Spring

InletPassage

ExhaustPassage

Inlet Cam& Valve

Exhaust Cam& Valve

VALVES

Bump, or lobe, on the Cam pushes the Valveopen during part of the rotation of the Cam


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The Fuel Injector is connected to ahigh pressure pump that is notillustrated.

It sprays a small amount of dieselfuel into the Cylinder at the end of

the Compression Stroke andbeginning of the Power Stroke.

The fuel is sprayed through severalvery small holes at very highpressure in order to form a fine mist

of droplets of fuel that will igniteeasily and burn quickly in the hot air.

Nozzle tip with severalsmall holes for fuel spray

INJECTOR


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The Diesel Engine 4 Stroke cycle consists of four distinct stages carried out whilstthe engine Crank Shaft does two complete turns (or as we say, two revolutions).

The Cams rotate once every two turns of the Crank Shaft, i.e. once per complete 4

stroke cycle.

A stroke is a movement of the Piston from one end of the Cylinder to the other end.

1st Stroke - INDUCTION. Fresh air is drawn into the Cylinder through the open InletValve by the Piston descending. The Inlet Valve closes when the Piston reachesbottom of Cylinder, trapping the fresh air in the Cylinder.

2nd Stroke - COMPRESSION. The Air is squeezed as the Piston rises, reachingabout 40 bar pressure. The air gets very hot (about 700 C) because of the workdone to it by the Piston. Diesel fuel is started to be Injected into the Cylinder asthe Piston gets near to the top.

3rd

Stroke - POWER. Fuel is injected into the Cylinder for a short while as the Pistonis near the top. The fuel spray ignites and burns in the hot air, creating evenhigher pressures and temperatures in the cylinder. The pressure of the hot gasespush the Piston down, delivering power to the crank-shaft and fly wheel.

4th Stroke - EXHAUST. The Exhaust Valve opens and the rising Piston pushes theburnt gases out of the Cylinder. When the Piston gets near the top the Exhaust

Valve closes and the Inlet Valve opens, ready to draw fresh air in again.

The 4 Stroke COMBUSTION CYCLE


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ANIMATION

Click here to run the animated Diesel engine combustionsequence.

(this link will only work if you run the presentation in Slide Show mode with Diesel 4S cycle.ppt in the same directory as this file)
http://diesel%204s%20cycle.ppt/http://diesel%204s%20cycle.ppt/


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End of Show

diesel 4s engine model (1)

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