The principle of a diesel engine is: 1. Intake stroke: When the intake stroke begins, the piston is at the top dead center. As the crankshaft rotates, the connecting rod moves the piston from the top dead center to the bottom dead center, gradually increasing the piston volume inside the cylinder. This causes the air pressure inside the cylinder to be lower than that in the intake pipe, allowing outside air to fill the cylinder; 2. When the piston moves to a certain point, it blocks the intake port, and the cylinder becomes a closed state. The piston continues to move upward, gradually increasing the pressure inside the cylinder; 3. Expansion and exhaust stroke: When the piston reaches a certain point before the top dead center, fuel is injected into the combustion chamber through the injector in a well-atomized state, mixing with air and spontaneously igniting. After the piston passes the top dead center, the gas pressure and temperature inside the cylinder rise sharply. The piston, driven by the high-temperature and high-pressure gas, moves from the top dead center to the bottom dead center, transmitting power to the crankshaft through the connecting rod. The crankshaft outputs power in a rotational form. As the piston moves downward, the cylinder volume gradually increases, and the pressure and temperature of the gas gradually decrease until the exhaust valve opens.
