Structure And Working Principle Of Common Rail Injector

Let's talk about the structure and working principle of common rail injector, which is the common fault of injector:

1. Initial state

When the injector solenoid valve is not triggered, the injector is closed, and the oil drain hole is also closed. The small spring presses the ball valve of the armature to the throttle hole, forming a common rail high pressure in the valve control chamber. Similarly, common rail high pressure is also formed in the injector. The pressure of the common rail pressure on the pressure of the control plunger section and the pressure of the nozzle spring and the opening force of the high pressure fuel on the cone surface of the needle valve are kept in balance with each other, so that the needle valve remains closed. state.

2. Fuel injection start state

When the solenoid valve is triggered, the armature opens the drain hole, the fuel flows from the valve control chamber to the cavity above, and returns to the fuel tank from the cavity through the oil return pipeline, so that the pressure in the control chamber is reduced; the pressure in the control chamber decreases, reducing At this time, the nozzle needle valve is opened and the injector starts to inject fuel.

3. Fuel injection end state

Once the solenoid valve is powered off and will not be triggered, the force of the small spring will press the solenoid valve down, and the ball valve will close the oil drain hole; after the oil drain hole is closed, the fuel enters the control room from the oil inlet hole to establish oil pressure, and this high pressure acts on the control On the plunger section, the pressure of the oil rail plus the spring force is greater than the pressure on the cone surface of the needle valve, so that the nozzle needle valve is closed.