To ensure proper operation and extend the service life of diesel engine fuel injectors, pay special attention to the following points during use and maintenance:
Fuel Quality and Cleanliness: Strictly adhere to seasonal changes by using clean diesel fuel of the specified grade. Fuel must undergo thorough settling and filtration before storage and refueling. Contamination by impurities, moisture, or acidic substances is strictly prohibited. Regularly maintain the diesel fuel filter and promptly drain sediment from both the filter and fuel tank to prevent minute impurities from accelerating wear on the needle valve assembly.
New Component Preparation: Newly replaced needle valve assemblies are typically coated with rust-preventative oil, which must be thoroughly removed before use. The correct procedure is to immerse the new injector assembly in 70–80°C (158–176°F) diesel fuel for 10 minutes. Then, repeatedly actuate the needle valve in clean diesel fuel to ensure complete removal of the rust-preventative oil. Cleaning without heating fails to thoroughly remove the oil, significantly increasing the risk of carbon buildup, sticking, or seizure of the needle valve during operation.
Avoid Engine Overheating: Prolonged overheating of the diesel engine causes excessive injector temperatures, leading to deformation and carbon buildup on components like the needle valve and orifice. This increases the risk of the needle valve seizing. Ensure the engine cooling system functions properly and avoid sustained full-load operation under high temperatures.
Regular Inspection and Adjustment: Regularly check injection pressure and atomization quality on an injector test bench. Excessive injection pressure causes overly fine atomization and prolonged fuel spray distance, allowing fuel to impact combustion chamber walls and result in poor combustion, knocking, and carbon buildup. Insufficient pressure leads to poor atomization, coarse fuel droplets, and reduced spray range, causing difficult starting, power loss, and black exhaust smoke. Atomization quality must achieve fine, uniform fuel mist without droplet splatter, meet required spray cone angles, ensure prompt cutoff, and produce a crisp sound.
Correct Installation and Sealing: When installing injectors, thoroughly remove carbon deposits from cylinder head mounting holes. Use specified-material (e.g., phosphor bronze) gaskets of qualified thickness; never substitute with asbestos sheets or similar materials. Tighten nuts evenly to specified torque to prevent unilateral pressure causing injector head deformation or misalignment, which may lead to air leaks or fuel leakage.
