1. Intake Stroke
During the intake stroke the exhaust valve are closed and only the inlet valve is open. As the piston moves down from the top dead center (TDC), air sucked in from the inlet manifold through the inlet valve.
2. Compression Stroke
When the intake stroke ends, piston begins to move upward again from bottom dead center (BDC). The inlet valve closes and air flow stop. The air in the cylinder is compressed as the piston moves up. As the air is compressed, its temperature rises as well as its pressure. Since a diesel engine burns fuel using the compression heat of air, the air must be compressed until its temperature reaches at least the self ignition temperature of the fuel.
The ignition temperature of the fuel decreases the higher the air pressure becomes. Theoritically, the compression pressure is determined by the compression ratio, so it is not directly related to the rotational speed. in reality, the compression pressure depend depends on various condition, such as rotational speed and leakage from the clearence betwen the piston and the cylinder. The compression pressure is heavily dependent on rotational speed in the low speed range, but not in the high speed range.
3. Combustion Stroke
Near the end of the compression stroke, fuel is injected from a nozzle in the form of high pressure mist. The compression heat of the air makes the fuel self ignite and burn. As a result, the pressure in the cylinder rises suddenly and the piston is pushed down. This force becomes the power that generates a turning force (torque) on the crankshaft.
4. Exhaust Stroke
When combustion ends and piston approaches bottom dead center, the exhaust valve opens. The combustion gas, which added work to the piston during the combustion stroke, is discharged into the atmosphere from the exhaust valve by the ascent of the piston. When the piston reaches top dead center, the intake stroke begins again and the same cycle is repeated.
An engine with a cycle consisting o these 4 strokes is called a 4- cycle engine
During the intake stroke the exhaust valve are closed and only the inlet valve is open. As the piston moves down from the top dead center (TDC), air sucked in from the inlet manifold through the inlet valve.
2. Compression Stroke
When the intake stroke ends, piston begins to move upward again from bottom dead center (BDC). The inlet valve closes and air flow stop. The air in the cylinder is compressed as the piston moves up. As the air is compressed, its temperature rises as well as its pressure. Since a diesel engine burns fuel using the compression heat of air, the air must be compressed until its temperature reaches at least the self ignition temperature of the fuel.
The ignition temperature of the fuel decreases the higher the air pressure becomes. Theoritically, the compression pressure is determined by the compression ratio, so it is not directly related to the rotational speed. in reality, the compression pressure depend depends on various condition, such as rotational speed and leakage from the clearence betwen the piston and the cylinder. The compression pressure is heavily dependent on rotational speed in the low speed range, but not in the high speed range.
3. Combustion Stroke
Near the end of the compression stroke, fuel is injected from a nozzle in the form of high pressure mist. The compression heat of the air makes the fuel self ignite and burn. As a result, the pressure in the cylinder rises suddenly and the piston is pushed down. This force becomes the power that generates a turning force (torque) on the crankshaft.
4. Exhaust Stroke
When combustion ends and piston approaches bottom dead center, the exhaust valve opens. The combustion gas, which added work to the piston during the combustion stroke, is discharged into the atmosphere from the exhaust valve by the ascent of the piston. When the piston reaches top dead center, the intake stroke begins again and the same cycle is repeated.
An engine with a cycle consisting o these 4 strokes is called a 4- cycle engine
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