What is the working principle of the BMW 3 Series fuel pump?
1 Answers
There are three key points to the working principle of the BMW 3 Series fuel pump: suction stroke, return stroke, and pumping stroke. Suction stroke: During the suction process, the downward movement of the pump piston provides the suction force, while the intake valve opens, allowing fuel to be drawn into the pump chamber. In the final third of the pump piston stroke, the fuel pressure regulator valve is energized, keeping the intake valve open during the initial upward movement of the pump piston to allow fuel return. Return stroke: To control the actual fuel supply, the intake valve remains open 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 accumulator absorbs the pressure fluctuations generated during this process. Pumping stroke: At the beginning of the pumping stroke, the fuel pressure regulator valve 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. When this pressure exceeds the pressure in the fuel rail, the outlet valve opens, and fuel is pumped into the fuel rail.
