The diesel fuel injection system atomizes the fuel and distributes the components that are mixed with the air in the combustion chamber.
It consists mainly of the injector and the injector body. The mounting position and angle on the cylinder head depends on the design of the combustion chamber.
Injectors are available in both open and closed versions. The open injector has a simple structure but poor atomization and is rarely used. Closed injectors are widely used in a variety of diesel engines. The diesel engine draws in pure air during the intake stroke. When the compression stroke is nearing the end, the diesel fuel is increased to 100 MPa or more by the fuel injection pump, and is injected into the cylinder through the injector to mix with the compressed high-temperature air in a short time to form a combustible mixture. Since the compression ratio of the diesel engine is high (generally 16-22), the air pressure in the cylinder can reach 3.5-4.5MPa at the end of compression, and the temperature is as high as 750-1000K (while the gas pressure of the gasoline engine at this time will be 0.6-1.2MPa). The temperature reaches 600-700K), which greatly exceeds the auto-ignition temperature of diesel. Therefore, after being injected into the cylinder, the diesel fuel is automatically ignited and burned after being mixed with the air in a short time. The air pressure in the cylinder rises rapidly to 6-9 MPa and the temperature rises to 2000-2500K. Under the push of high pressure gas, the piston moves downward and drives the crankshaft to rotate, and the exhaust gas is also discharged into the atmosphere through the exhaust pipe.