Type and structure of fuel injector

A. According to the structure of the oil injection port, it can be divided into: pin type and hole type.  

B, according to the coil resistance value: high resistance (13 ~ 16 ω), low resistance (2 ~ 3 ω).  

C, by use: MPI, SPI.  

D, according to the fuel position: upper end oil supply type, side oil supply type. 

The injection process  

A. The fuel injector is equivalent to the solenoid valve.  

B. When energized, the electromagnetic coil generates electromagnetic force, the armature and needle valve suck up, the injector is opened, and the gasoline is sprayed into the inlet or the intake pipe through the nozzle hole.  

C. When the power is off, the electromagnetic force disappears, the armature and needle valve close the nozzle hole under the action of the return spring, and the injector stops spraying.  

D. The power-on and power-off of fuel injector are controlled by electric pulse by ECU.  

E. The amount of fuel injection is determined by the width of the electrical pulse.  Pulse width = injection duration = injection volume.  

F, the general needle valve lift is about 0.1mm, and the injection duration is in the range of 2~l0ms.