The function of DK28 diesel engine parts delivery valve

The oil outlet valve of marine diesel engine parts is a one-way valve. Under the action of spring pressure, the upper conical surface of the valve closely matches with the valve seat. Its function is to isolate the high-pressure oil pipe from the upper cavity of the plunger when the supply is stopped to prevent high-pressure oil. The oil in the pipe flows back into the fuel injection pump. The structure is simple and reliable, does not change the working structure parameters, and the work is not affected. It can be repeatedly disassembled and assembled. The processing and production are simple, and it is convenient for on-site assembly.

The role of the delivery valve

(1) Prevent dripping before fuel injection and increase the injection speed: When the fuel injection pump supplies fuel, after the oil pressure is higher than the pre-tightening force of the delivery valve spring and the residual pressure in the high-pressure oil pipe, the delivery valve rises and its seal is sealed The conical surface leaves the valve seat. It is necessary to wait until the pressure relief belt on the delivery valve completely leaves the guide hole of the valve seat before the fuel in the pump oil chamber can enter the high-pressure fuel pipe.

(2) Prevent dripping after fuel injection and increase the closing speed: When the fuel supply is stopped, the passage between the high-pressure fuel pipe and the pump chamber will be cut off when the lower edge of the pressure relief belt of the delivery valve enters the duct. When the oil outlet valve is fully seated, it drops a distance h, so the volume of the high-pressure oil pipe is increased, so that the oil pressure drops rapidly by 1 MPa to 2 MPa, and the oil is cut off quickly and simply, preventing oil pressure fluctuations and “pipe shrinkage”. "And produce dripping oil after spraying.

(3) Prevent fuel backflow and maintain a certain residual pressure in the high-pressure fuel pipe.