Diesel engines are compression ignition, and the work of diesel engines is composed of four processes of intake air to form a working cycle. A diesel engine that takes four processes to complete one working cycle is called a four-stroke diesel engine. The working principle of “intake stroke” is now explained in detail with reference to the title.
The first stroke is intake air, its task is to fill the cylinder with fresh air. When the intake stroke begins, the piston is at top dead center, and some exhaust gas remains in the combustion chamber in the cylinder.
When the crankshaft rotates, the connecting rod moves the piston from top dead center to bottom dead center, and at the same time, the intake valve is opened by using a transmission mechanism connected to the crankshaft.
With the downward movement of the piston, the volume above the piston in the cylinder gradually increases: the air pressure in the cylinder is lower than the pressure in the intake pipe, so the outside air is continuously charged into the cylinder.
When the piston continues to move down and approaches bottom dead center, the air flow rushing into the cylinder still has a very high speed and a large inertia. In order to use the inertia of the airflow to increase the inflation amount, the intake valve closes after the piston passes the bottom dead center. Although the piston is going up at this time, due to the inertia of the air flow, the gas can still be charged into the cylinder.