What are the reasons for the diesel high-pressure fuel injection pump not delivering oil?
1 Answers
There are several reasons why the high-pressure fuel pump may not deliver oil: the auxiliary shutdown switch is in the connected state; the rail pressure is too low; the battery voltage is too low; the synchronization signal is incorrect. The working principle is as follows: 1. Suction stroke: During the suction process, the downward movement of the pump piston provides the power for suction, while the intake valve opens, allowing fuel to be drawn into the pump chamber. In the last third of the pump piston stroke, the fuel pressure regulator is energized, keeping the intake valve open during the initial upward movement of the pump piston to allow fuel return. 2. Return stroke: To control the actual fuel supply, the intake valve opens during the initial upward movement of the pump piston, allowing excess fuel to be pushed back to the low-pressure side by the pump piston. The pressure damper absorbs the pressure fluctuations generated during this process. 3. Pumping stroke: At the beginning of the pumping stroke, the fuel pressure regulator is de-energized, causing the intake valve to close under the combined action of the rising pressure in the pump chamber and the closing spring inside the valve. The upward movement of the pump piston creates pressure in the pump chamber, and when this pressure exceeds the pressure in the fuel rail, the outlet valve opens, allowing fuel to be pumped into the fuel rail.
