Structural principle editing

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 the value of high resistance coil (2 ～ 13 Ω), low resistance coil.

c. According to the use: MPI, SPI.

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

Structure diagram of fuel injector

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

classification

(1) Needle type electromagnetic injector

When fuel injection, the armature drives the needle valve to rise about 0.1 mm from its seat surface, and the fuel is ejected from the precise clearance. In order to make the fuel atomized sufficiently, a section of injection shaft needle was grinded out at the front end of needle valve. The suction and falling time of the injector is about 1 ~ 1.5ms.

(2) Ball valve type electromagnetic injector

Ball valve needle weight is light, spring preload is large, can obtain a wider dynamic flow range. The ball valve has the function of automatic centering and good sealing. At the same time, the ball valve simplifies the structure of the metering part, which helps to improve the accuracy of fuel injection.

(3) Disc valve type electromagnetic injector

The combination of light weight valve plate and hole seat with magnetic optimized injector assembly not only has a large dynamic flow range, but also has a strong anti clogging ability

(4) Lower fuel injector

With the bottom fuel supply mode, the fuel can flow out from the upper part through the injector cavity around the valve seat area, which has a very obvious cooling effect on the metering part of the injector, so it can effectively prevent the generation of air resistance and improve the reliability of hot start of automobile.

In addition, the bottom injection injector can save the fuel manifold and reduce the cost