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The working principle of the injector, the composition, the type of action, the installation and inspection methods


How the injector works

The fuel injector is actually a solenoid valve, its nozzle is facing the intake valve (multi-point out-of-cylinder injection), and its tail is connected to the fuel distribution pipe.

The fuel comes from the high-pressure oil circuit, flows to the fuel injector through the channel, and flows to the control chamber through the orifice. The control chamber is connected to the fuel circuit through an oil drain hole controlled by the solenoid valve. When the oil drain hole is closed, the hydraulic pressure acting on the needle valve control piston exceeds its force on the pressure bearing surface of the injector needle valve. As a result, the needle valve is forced into the valve seat and isolates and seals the high pressure passage from the combustion chamber.

When the solenoid valve of the fuel injector is activated, the oil drain hole is opened, which causes the pressure in the control chamber to drop. As a result, the hydraulic pressure on the piston also drops. Once the hydraulic pressure drops below the pressure acting on the nozzle needle valve bearing The pressure on the pressure surface, the needle valve is opened, and the fuel is injected into the combustion chamber through the nozzle hole. The fuel injection quantity is determined by the electrical pulse width; pulse width = fuel injection duration = fuel injection quantity

The injector should meet the requirements of different types of combustion chambers for the injection characteristics. Generally speaking, the injection should have a certain penetration distance and spray cone angle, as well as good atomization quality, and it should not occur at the end of the injection. Drip phenomenon.

The five components of the injector

The injector is mainly composed of electromagnet assembly, armature assembly, valve assembly, injector body and nozzle coupler.

1. Electromagnet components

It is composed of coils, cores, chambers, electrical connectors, and tight caps. It will generate electromagnetic force when it is energized, attracting the armature plate to move up, and controlling the nozzle needle valve.

2. The armature assembly

It is composed of armature core, armature disc, armature guide, buffer gasket, valve ball, support seat, etc. It moves up and down under the action of electromagnetic force, and is one of the control components that controls whether the injector is sprayed or not.

3. Valve components

It is composed of two parts, the valve seat and the ball valve, and the gap between the two is only 3 to 6 microns. The valve assembly is one of the main moving parts that control the fuel return of the injector.

4. Injector body

The injector body has high and low pressure oil passages and is the main pressure bearing component.

5. Grease fittings