1. The diesel oil is not clean. There are impurities in the high-pressure oil pipe, so that the needle valve coupler is not closed tightly. The high-pressure gas in the combustion chamber is reversed and the needle valve is burned out. In addition, the dirt on the parts such as the fuel pressure regulating spring and the tappet is moved to the upper part of the injector needle through the injector tappet, or the cotton rope and the lead wire on the oil path for preventing oil leakage are injected into the spray through the high pressure oil pipe. The oil burner will cause the needle valve to be stuck.
2. The machine temperature is too high, the injector is poorly cooled, and the needle valve is stuck. The oil supply time is too late, the cooling water channel is excessive or clogging, the pump impeller end face is worn, the engine is overloaded for a long time, and the engine is overheated.
3. The oil discharge valve is worn out, so that the oil drop phenomenon occurs when the injector stops spraying, so that the spray nozzle burns coke and the jam occurs.
4. When the injector is installed, the gasket or gasket is damaged, causing air leakage, causing the local temperature of the injector to be too high and being stuck.
5. The injection pressure is too low, causing high pressure gas in the combustion chamber to ruminate;
6. Reasons for parts manufacturing, such as the injector mounting hole on the cylinder head is too tightly matched with the injector, the clearance between the needle valve body and the cylinder head is too small, and the cylinder head injector mounting hole is too deep.
Second, the nozzle repair method: first put the stuck injector into the diesel or oil to warm, then take out the cloth wrapped, then clamp the needle valve with a hand pliers and slowly move the needle The valve is removed from the needle valve body. A small amount of cleaning oil is dripped in the needle valve body, so that the needle valve is repeatedly moved in the needle valve body until the needle valve can move freely in the needle valve body. If the sealing surface of the needle valve has burn marks, it should be ground with abrasive paste. Pay attention to the amount of abrasive paste and grinding time when grinding. Install the cleaned needle valve coupler on the injector and adjust the injection pressure to re-use.