Injector dripping oil
Symptoms of failure: continuous fuel injection, blockage of nozzle holes, so that the fuel cannot be atomized, uneven fuel injection, poor starting performance, work knocking, exhaust smoke, increased carbon deposits, resulting in reduced engine power, increased fuel consumption, and increased wear.
Failure cause analysis: (1) The sealing cone surface of the needle valve and the needle valve body is severely worn, and groove marks appear, which widens the contact surface of the cone surface sealing ring, deforms the cone surface, and increases the roughness, resulting in oil dripping from the injector. Carbon deposits are formed near the nozzle hole, and even the nozzle hole is blocked. (2) The higher the residual pressure of the high-pressure fuel pipe (that is, the pressure of the high-pressure fuel pipe when no fuel is injected between the two fuel injection nozzles), the more serious the fuel dripping from the fuel nozzle. The main reason affecting the residual pressure is that the oil outlet valve is even pieces. The oil dripping failure of the fuel injection nozzle is not all on the fuel injection nozzle, but is closely related to the sealing of the fuel delivery valve assembly. Abnormal wear of the oil delivery valve will cause oil dripping from the injector. (3) The needle valve of the fuel injector and the guide surface of the needle valve body have poor sliding performance and work blockage, or the guide surface of the needle valve and the needle valve body is severely worn, the contact between the needle valve body and the injector body is not strict, or the needle valve and the needle The sealing tapered surface of the valve body is cushioned by mechanical impurities, and if it is not closed tightly, it will also cause the fuel injector to drip oil.
