Fig: Principle cycle of diesel engine
A diesel engine uses high compression [intake air that is compressed / squished] into a very small space inside each cylinder causing extreme heat! This is called 'Heat Of Compression' which ignites a very fine high pressure mist of diesel fuel that is injected into the cylinder at the exact time.
So you now know that a gasoline engine needs a high energy spark to run while a diesel uses 'Heat Of Compression'
THE FOUR STROKE PRINCIPLE
Every engine today runs on FOUR STROKES or FOUR CYCLES- both these terms mean the same. Here is how the four stroke diesel engine operates.
The four strokes are: INTAKE-COMPRESSION-POWER-EXHAUST. The pistons, valves and injectors work together in each cylinder in a set sequence over and over.
1} INTAKE STROKE:
Intake valves in the cylinder head open allowing pressurized air to enter each cylinder while the piston is travelling downward.{the pressurized air supply is made possible by the TURBOCHARGER which pushes air into the intake system giving the diesel engine a boost of air to keep up with instantaneous injection of fuel}
2} COMPRESSION STROKE:
When the piston starts to make it's way back upward the valves close which traps the intake air in the cylinder which allows compression to take place, the HEAT OF COMPRESSION is reached when the piston reaches the top of the cylinder, the diesel fuel is then injected into the cylinder at the precise time.
3} POWER STROKE:
After injection takes place an explosion occurs in the cylinder because of the combination of heat and atomized diesel fuel. This causes the piston to be forced downward which produces torque and the horsepower required from a typical diesel engine.
4} EXHAUST STROKE:
After the power stroke the piston moves upward once again while the exhaust valves open allowing the previously ignited gases to escape to the atmosphere out the exhaust system.
Every engine today runs on FOUR STROKES or FOUR CYCLES- both these terms mean the same. Here is how the four stroke diesel engine operates.
The four strokes are: INTAKE-COMPRESSION-POWER-EXHAUST. The pistons, valves and injectors work together in each cylinder in a set sequence over and over.
1} INTAKE STROKE:
Intake valves in the cylinder head open allowing pressurized air to enter each cylinder while the piston is travelling downward.{the pressurized air supply is made possible by the TURBOCHARGER which pushes air into the intake system giving the diesel engine a boost of air to keep up with instantaneous injection of fuel}
2} COMPRESSION STROKE:
When the piston starts to make it's way back upward the valves close which traps the intake air in the cylinder which allows compression to take place, the HEAT OF COMPRESSION is reached when the piston reaches the top of the cylinder, the diesel fuel is then injected into the cylinder at the precise time.
3} POWER STROKE:
After injection takes place an explosion occurs in the cylinder because of the combination of heat and atomized diesel fuel. This causes the piston to be forced downward which produces torque and the horsepower required from a typical diesel engine.
4} EXHAUST STROKE:
After the power stroke the piston moves upward once again while the exhaust valves open allowing the previously ignited gases to escape to the atmosphere out the exhaust system.
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