SUBJECT – EME

TOPIC- 4-STROKE DIESEL ENGINE

THE CREATORS

• Monika Mehta B120010241• Mridul Singh Rawat B120010243• Salin manchanda B120010351• Vikas Sharma B120010434• Vivek Sharma B120010443

BRIEF INTRODUCTION

• A diesel engine is an internal combustion engine.

• It uses the heat of compression to initiate ignition to burn the fuel that has been injected into the combustion chamber.

• The engine was developed by German inventor Rudolf Diesel in 1893.

• The engine works on the principle of diesel cycle

DIESEL CYCLE

The Diesel cycle is the thermodynamic cycle which approximates the pressure and volume of the combustion chamber of the Diesel engine, invented by Rudolph Diesel in 1897. It is assumed to have constant pressure during the first part of the "combustion" phase.

RUDOLPH DIESEL

P-V AND T-S DIAGRAM FOR DIESEL CYCLE

P-V GRAPH T-S GRAPH

STROKES INVOLVED IN DIESEL ENGINE

1. INTAKE stroke: Piston descends from the TDC to BDC increasing the volume of the cylinder. Air is forced into the cylinder through the intake port.

2. COMPRESSION stroke: with both valves closed, the piston returns to TDC compressing the air into the combustion chamber of the cylinder head. Temperature gets increased to hundred degrees.

3. POWER stroke: While the piston is close to TDC, the compressed fuel injected into a diesel engine ignites due to the heat generated in the air during the compression stroke.

4. EXHAUST stroke: Here, the piston once again returns to top dead centre while the exhaust valve is open. The spent fuel-air mixture is expelled.

BASIC COMPONENTS USED

1. Crankshaft2. Cam shaft3. Cylinder head4. Piston 5. And many more…

DETAILED VIEW OF THE COMPONENTS

1. CRANKSHAFT– Singular costliest item in diesel engine.– Medium of transforming reciprocating motion to

rotary motion.– Balance weights can be either bolted up or

welded.

2. CAM SHAFT– Performs the vital role of opening & closing inlet &

exhaust valves.– Allow timely injection of fuel inside the cylinder.– Usually 3 cams for each cylinder-

2 outer cams for exhaust & inlet valves 1 central cam for fuel injection.

3. CYLINDER HEAD– CH is held on the cylinder liners by 7 hold down

studs.– Subjected to high shock stress & combustion

temperature at the lower face.– Complicated casting where cooling passages are

cored for holding water.– Space had been provided for passage of inlet air &

exhaust gases.– Space for fuel injection nozzles, valve guides &

valve seat.

4. PISTON–Compresses the air to required pressure &

temperature–Receives the thrust of expanding gases &

transmits the force through connecting rod.–With the help of piston rings, prevents

leakage of gas from combustion chamber.

5. SOME OTHER PARTS– PISTON RINGS

• Seal the combustion chamber• Prevent blow by of air & high temperature combustion

gases.– CONNECTING ROD• Connects piston & crank shaft• Medium of converting reciprocating motion to rotary

motion.– LINERS• Forms the wall of the combustion chamber.• Guides the movement of piston.

A SHORT SUMMARY

• Diesel Engine relies upon compression ignition.• Compression ratio lies b/w 16:1 and 25:1.• Temp. increases to 700C to 900C.• Piston approaches TDC, fuel is injected.• Ignition instantly occurs, causing a rapid increase in

cylinder temperature & pressure.• Piston is driven downward with great force, pushing

on the connecting rod & turning the crankshaft. • Exhaust gases are expelled then.

ADVANTAGES

• More efficient.• More reliable.• More durable.• Release less amount of harmful fumes.• Easily turbo-charged.• Produce minimal carbon monoxide.• Can easily accept synthetic fuels.

CAN ACCEPT SYNTHETIC FUELS

NO HARMFUL EMISSIONS

DISADVANTAGES

• More expensive. • Occasionally servicing can be more costly.• Parts tend to be more expensive.• The cost of diesel at the pump is higher.• Contribute to Greenhouse effect.• Generally more noisy.

EXPENSIVEA BIT NOISY