4 Major Reasons the Injector Needle Valve Is Damaged

by MOU YONG HONG on December 01, 2021

The injector needle valve coupling is one of the three precision couplings of the diesel engine fuel supply system. Its technical status affects the diesel engine's power, economy, stability, power, working stability, noise, and service life. Both have obvious effects. Diesel generator injector needle valve assembly is damaged, causing the injector to drip. The performance is that when the temperature of the diesel engine is low, it is difficult to start, the exhaust pipe emits white smoke, and the diesel engine becomes black smoke when the temperature rises, and fuel consumption is high.


The reason for the damage of the injector needle valve assembly:


1. The diesel filter does not work. Diesel impurities cause accelerated wear of the needle valve and the needle valve is not closed tightly. The high-pressure combustion gas in the combustion chamber causes the needle valve fittings to ablate. The injector needle valve is a kind of precision matching parts, which are all reground in pairs during processing. The matching clearance is only 0.003~0.005mm. Because this clearance is too small, the cleanliness requirements for diesel are higher. A slight impurity in the diesel will cause it to jam.

2. Improper cleaning or incorrect installation. The gasket at the lower end of the injector is a copper gasket. The gasket is not flat or deformed and causes air leakage, which not only affects the power but also causes the needle valve to sinter and jam due to high temperature.

3. The assembly precision requirements of the mating parts are very strict. VEP Engine parts recommend that users not blindly disassemble it. Disassembly and installation will cause wear and tear. If it is coupled with improper disassembly and installation, it will worsen and lead to a decline in its technical status.

4. The injector has poor heat dissipation during long-term overload operation, or the fuel supply time is too early or too late, and the incomplete diesel combustion produces carbon deposits, which causes the injector to freeze due to poor heat dissipation.

Measures to prevent damage to the needle valve assembly of the diesel injector:

1. Choose qualified diesel oil and replace the diesel filter element regularly.

2. Choose clean diesel when cleaning, and clean the container with diesel. When cleaning, be careful and patient, and the movement should be light and not damage the needle valve.

3. Clean up the carbon deposits of the fuel injector during installation. If the sealing copper sheet has unevenness or scratches, it should be replaced. When locking the screw, both sides should be locked at the same time with the same strength; when the high-pressure oil pipe is installed, the sundries on the joint should be cleaned. Prevent metal debris from entering.

4. Diesel engines should pay attention to daily maintenance and should not be overloaded for a long time.

Diesel generator injector needle valve coupler damage can be repaired measures:

 1. The fuel injector can be disassembled, and a little chromium oxide fine grinding paste is applied to the needle valve head (be careful not to stick to the needle valve hole) to grind the cone surface.

2. Wash it with diesel oil and put it into the injector for testing.

3. If it still cannot be used, the needle valve assembly needs to be replaced.


Please note, comments must be approved before they are published