New Injector Nozzle Dlla157p1424 0433171886 OE Me 226718 Me222914 for Fuel Injector 0445120048

1. The fit gap of the needle valve couple is generally 2~4μm. Considering the actual processing level, the fit gap is 1~10μm in the research, the length of the needle valve sealing surface is 8.4mm, the eccentricity rate of the needle valve is zero, and the inclination rate is zero. , set the inlet port pressure to 120MPa, simulate and calculate the fuel leakage rate in the gap of the needle valve coupler under different oil film thicknesses, as the thickness of the oil film increases, the leakage rate of the needle valve coupler increases, and the leakage rate gradient increases. When the film thickness is 1μm, the leakage rate is 0.025mL/s, and when the film thickness becomes 10μm, the leakage rate is 6.37mL/s, an increase of nearly 25 times. When the oil film is thin, the leakage rate changes in a curve with the film thickness, and when the oil film exceeds 6 μm, the leakage rate changes nearly linearly with the film thickness.

2. The length of the sealing surface is an important parameter of the needle valve seal. In theory, when the needle valve seal length tends to be infinite, its leakage under static conditions is zero due to the viscous friction of the wall surface. In practice, due to the design requirements of the compact structure of the injector, the sealing length of the needle valve coupling is limited. Under different needle valve sealing surface lengths, the sealing characteristics of the needle valve couple, as the needle valve sealing surface length increases, the leakage rate decreases rapidly, and the leakage rate gradient also decreases.