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.

Structural principle

Type and structure of fuel injector

a. According to the structure of fuel injection port, it can be divided into pintle type and hole type.

b. According to coil resistance value: high resistance (13 ~ 16 Ω), low resistance (2 ~ 3 Ω).

c. According to the use: MPI, SPI.

d. According to fuel position: upper oil supply type, side oil supply typ

Fuel injection process

a. The injector acts as a solenoid valve.

b. When the solenoid coil is energized, the armature and needle valve are sucked up, the fuel injector is opened, and gasoline is injected into the intake port or intake pipe through the nozzle hole.

c. When the power is cut off, the electromagnetic force disappears, the armature and needle valve close the injection hole under the action of the return spring, and the fuel injector stops fuel injection.

d. The power on and off of the fuel injector is controlled by the electronic control unit with electric pulse.

e. The injection quantity is determined by the electric pulse width. Pulse width = injection duration = injection quantity.

f. Generally, the lift of needle valve is about 0.1 mm, while the injection duration is in the range of 2 ~ 10 ms.