DK28 diesel engine parts injector prevention and elimination methods

The fuel injector is one of the important parts of the DK28 diesel engine accessory fuel system. It is prone to malfunction if it works under high temperature and high pressure for a long time.

1 The injector needle valve is stuck

When the needle valve is stuck, the injector will not work, and the single-cylinder diesel engine will shut down.

cause of issue:

(1) Injector marine diesel engine parts have poor heat dissipation. The fuel injector extends into the combustion chamber of the cylinder, and the fuel combustion temperature in the combustion chamber reaches about 2000°C. If the fuel injection nozzle cannot dissipate the heat well, the fuel injection nozzle will overheat, causing the needle valve assembly to jam. The main reasons for the poor heat dissipation of the fuel injector are: the copper gasket for the installation of the fuel injector does not meet the requirements. If the gasket is not clean, use asbestos rope or waste cylinder gasket to replace the copper gasket, which affects heat dissipation; the adjustment of the fuel supply time is not accurate, causing fuel The afterburning period of combustion is too long, causing the injector to overheat and jam; the sealing cone of the needle valve is damaged, and the combustible gas in the cylinder flows into the guide surface to form carbon deposits and jam.

(2) Diesel oil is not clean, water or acidic substances make the needle valve rust; the machine is parked for a long time, water or water vapor corrodes, or the needle valve is rusted when parked in the open or wet place for a long time.

(3) The needle valve is stuck due to damage caused by disassembly, improper cleaning or incorrect installation.

(4) The anti-rust oil is not removed when installing a new fuel injector, and the anti-rust oil will stick to the needle valve after being melted at high temperature.

Precaution:

(1) Use qualified fuel injectors instead of substitutes. The copper washers of the fuel injectors must meet the technical requirements to remove carbon deposits. It is forbidden to substitute asbestos ropes and waste cylinder gaskets.

(2) The fuel supply advance angle, gas distribution phase and fuel injection pressure must meet the technical requirements.

(3) When disassembling and assembling the fuel injection nozzle, do not touch the needle valve assembly and do not mix. Install the fuel injector assembly, and pay attention to the cleaning of the fuel injector mounting seat hole. Do not add too much copper gasket, otherwise it will change the spray distance of the fuel injector, causing incomplete combustion, overheating of the fuel injector, carbon deposits, and seizure; do not use asbestos rope and other materials to replace the copper gasket, otherwise it will affect the fuel injection Heat dissipation. When installing the fuel injector fixing bolts, the torque should meet the requirements and tighten them evenly in 3 to 4 times.

Carbon deposit in the fuel injector is blocked

When the carbon deposit in the nozzle hole is half blocked, the fuel injection volume of the fuel injector decreases, the fuel return volume increases, and the diesel engine is weak. When the carbon deposit in the nozzle hole is fully blocked, the diesel engine's failure phenomenon is the same as the nozzle needle valve stuck failure phenomenon, that is, the injector does not inject fuel and does not work.

cause of issue:

The main reason for the clogging of the fuel injector with carbon deposits is that diesel and engine oil are not completely burned in the cylinder, and they combine with the dust of the air intake to form carbon deposits. Carbon deposits adhere to the valves, pistons, cylinder liners, exhaust pipes and fuel injection nozzles in the combustion chamber.

Precaution:

(1) Ensure that the fresh air in the cylinder of the diesel engine is sufficient and the exhaust gas is exhausted cleanly.

(2) Keep the technical condition of the fuel injector in good condition, the fuel injection pressure should be within the specified range, the atomization should be good, and no oil drips or leaks.