The fuel injector is divided into open type and closed type. The structure of open injector is simple, but the atomization is poor, so it is seldom used. Closed injector is widely used in various diesel engines. Pure air is inhaled in the intake stroke of diesel engine. At the end of the compression stroke,Injector injection pulse width The oil pressure of diesel oil is increased to more than 100MPa by the fuel injection pump, and injected into the cylinder through the fuel injector, and then mixed with the compressed high-temperature air in a short time to form a combustible mixture. Due to the high compression ratio of diesel engine (usually 16-22), the air pressure in the cylinder can reach 3.5-4.5mpa at the end of compression, and the temperature can reach 750-1000k (while the mixture pressure of gasoline engine will be 0.6-1.2mpa, and the temperature can reach 600-700k), which greatly exceeds the spontaneous combustion temperature of diesel. Therefore, diesel fuel will ignite and burn automatically after mixing with air in a short period of time after it is injected into the cylinder. The air pressure in the cylinder rises rapidly to 6-9mpa and the temperature rises to 2000-2500k. Driven by high pressure gas, the piston moves downward and drives the crankshaft to rotate to work. The exhaust gas is also discharged into the atmosphere through the exhaust pipe.

1.The fuel injection timing and fuel metering are completely separated, and the injection pressure and injection process are timely controlled by ECU.

2. According to the working conditions of the engine, the injection pressure, injection starting point and duration can be adjusted to achieve the best control point.

3. It can realize high injection pressure and pre injection of diesel.

Compared with gasoline engine, diesel engine has lower fuel consumption rate (30% lower than gasoline engine on average), and diesel price is lower, so fuel economy is better; at the same time, the speed of diesel engine is generally lower than that of gasoline engine, and the torque is larger than gasoline engine, but its quality is high, noise is high, manufacturing and maintenance costs are high, and emission is also worse than gasoline engine. But with the development of modern technology, these shortcomings of diesel engine are gradually overcome.