The figure below shows the working principle of a typical vane fuel pump. The four steel blades slide along the rotor radial direction in the chute formed on the rotor. One end of the blade is pressed against the inner wall of the pump barrel, and the other end is in contact with the floating shaft through a spring. The cavity inside the rotor is divided into four working chambers by the blades and the floating shaft. The pump barrel is fixed on the casing of the pump, and there are inlet and outlet ports on both sides. The power of the rotor can be engine driven or motor driven.
Vane fuel pump
In the picture, the rotor rotates clockwise when working. Since the pump barrel and the rotor are eccentric, the volume of each working chamber changes continuously with the rotation of the rotor. When the blade turns to the inlet side, the volume of the working chamber becomes larger, resulting in a local low pressure area To draw the fuel in the fuel tank into the working chamber. When the blade turns to the outlet side, the volume of the working cavity becomes smaller, squeezes out the fuel, and flows to the carburetor.
When the pump outlet pressure is greater than the specified value, the pressure acting on the lower surface of the pressure relief valve overcomes the spring force, and the pressure relief valve is opened upward to guide the excess fuel from the pump outlet back to the inlet, so that the fuel supply pipe between the pump outlet and the carburetor The fuel pressure in the road is always kept within the specified value. When the vane pump fails during engine operation, as long as the inlet pressure of the pump is slightly greater than the outlet pressure, the pressure acting on the surface of the bypass valve plate overcomes the thin spring force and opens the bypass valve plate downward to make the fuel full. Flow to the engine carburetor.
The head of the pump is equipped with a fuel supply pressure adjustment device, which can automatically adjust the fuel pressure at the pump outlet to be within the specified range. If the fuel pressure is abnormal when the pump is working, first check the pressure adjustment device, and correct the pressure by adjusting the screw through the test method.