Diesel Engine By: Muhammad Yousuf Chhajro

Outlines

Diesel engine Two stroke Four stroke Differences Applications

Engine is a motor which converts chemical energy into mechanical energy

The diesel engine also known as a compression-ignition engine that uses the heat of compression of air to initiate ignition and burn the fuel

The air required for the diesel engine is drown through the air filter from the atmosphere and compressed inside the cylinder.

The fuel from the diesel engine is drawn through a filter and injected into the cylinder through fuel injectors.

Because of the high temperature and pressure of the compressed air, the fuel burns and the burnt gases expand to do work on the moving part inside the cylinder called piston.

This movement of the piston rotates a flywheel and the engine is directly coupled to electric generator

The gases after expansion inside the cylinder is exhausted into the atmosphere and passes through a silencer in order to reduce the noise.

Incoming air is compressed until its temperature reaches about 1,000°F (540°C).

Diesel engines are manufactured in two

stoke and four stroke versions

Two stroke

A two-stroke, or two-cycle, engine is a type of internal combustion engine

which completes a power cycle in only one crankshaft revolution and with two strokes, or up and down movements, of the piston

Intake: Air is drawn into the crank case(a case or covering enclosing a crankshaft) by vacuum and then into the cylinder.

Compression: Air is then compresses inside the cylinder.

Power: Fuel is injected trough fuel injector air is ignited forcing the piston down exposing the exhaust port.

Exhaust: The exhaust gases are forced out by the incoming fuel air mix

Four stroke

A four-stroke engine (also known as four-cycle) is an internal combustion engine in which the piston completes four separate strokes

A stroke refers to the full travel of the piston along the cylinder

Intake Stroke• Piston moves from TDC(top dead

center) to BDC(bottom dead center) creating vacuum in the cylinder

• Intake valve opens allowing only air to enter the cylinder and exhaust valve remains closed

Compression Stroke• Both valves stay closed

Piston moves from BDC to TDC, the air is compressed

• Compressing the air to this extent increases the temperature inside the cylinder to above 1000 degree F

Power Stroke• Both valves stay closed• When the piston is at the end of

compression stroke(TDC) the injector

• sprays a mist of diesel fuel into the cylinder.

• When hot air mixes with diesel fuel an explosion takes place in the cylinder

• Expanding gases push the piston from TDC to BDC

Exhaust Stroke• Piston moves from BDC to TDC• Exhaust valve opens and the

exhaust gases escape• Intake valve remains closed

Uses of Diesel Engine