Fuel injectors,commonly known as nozzles,are precision components of the fuel system in diesel engines.They are installed on the cylinder head and are responsible for atomizing high-pressure diesel,accurately spraying it into the combustion chamber,and determining engine start-up,power,fuel consumption,and exhaust quality.Divided into two categories:mechanical fuel injectors and common rail electronic fuel injectors,common rail injectors are the main type of electronic fuel injectors for China III and later electronic fuel injection models.

　　The mechanical fuel injector relies on the diesel pressure from the high-pressure Oil Pump to open the needle valve and complete the injection;The common rail injector is continuously supplied with high-pressure fuel by the common rail pipe.The ECU controls the solenoid valve to turn on and off,accurately controlling the timing,quantity,and frequency of fuel injection.It can achieve pre injection,main injection,and post injection,with softer combustion and reduced noise and emissions.The entire assembly includes nozzle fittings(needle valve,nozzle hole),springs,seals,and electronic fuel injection models with high-speed solenoid valves and control valve core components added.The nozzle needle valve and nozzle hole have a clearance of micrometer level,which is extremely sensitive to the cleanliness of diesel fuel.

　　High pressure diesel enters the injector,and when the opening pressure is reached,the valve is lifted.The small injection holes disperse the diesel into fine oil mist,which is fully mixed and burned with the compressed air in the cylinder;After the injection is completed,the spring pushes the needle valve to quickly close,stopping the oil supply.A small amount of diesel is used for internal lubrication and cooling,and flows back to the fuel tank through the return pipe.The nozzle head is directly exposed to the high-temperature gas in the combustion chamber and is subjected to repeated high-pressure fuel flushing,making it a vulnerable consumable.

　　Under heavy load conditions in mines,the fuel injector sprays at high temperatures and high loads for a long time,and the nozzle is prone to carbon deposition and nozzle wear;The medium load condition of earthwork is relatively stable.Oil Nozzle faults do not directly report individual fault codes.Common manifestations include idle shaking,cylinder shortage,decreased power,black smoke,and soaring fuel consumption.After the oil nozzle is damaged,poorly atomized diesel flows into the oil pan along the cylinder wall,diluting the engine oil and seriously causing cylinder pulling and shaft holding.

　　The fuel injector is a high-precision component,and the internal parts cannot be easily repaired by hand.It must be verified by a professional test bench.Familiar with the working logic of fuel injectors and emphasizing diesel filtration can reduce early damage to fuel injectors,avoid major secondary engine failures,and ensure stable construction of excavators.