Eight injectors burned

First, the leakage of gasket A S195 diesel engine bite the nozzle. The operator removed the injector and checked that the gasket between the injector and the body was missing. The relative angle between the injector and the starting nozzle was changed. The injector extended out of the combustion chamber and affected the combustion chamber. The mixture of fuel and air burned, resulting in aggravated coke, killing the injector. After replacing the gasket, the fault will be eliminated. Second, free to pad a 495-type diesel engine, in which the first cylinder of the nozzle is not used for a long time, it is scrapped due to serious carbon deposition burned. Replace the nozzle with a new nozzle and burn it out for a short time. After inspection, the above failure was caused by the collision of the injector mounting hole of the diesel engine cylinder with a large grain of cast iron. To prevent this, the operator placed three copper gaskets in front of the injector. The fuel injector is retracted into the throat of the cylinder head. Diesel fuel cannot be injected into the combustion chamber in accordance with design requirements, resulting in poor combustion and increased coke. The nozzle assembly is continuously damaged. Third, the material hardness of the pressure cap is poor. A S195 diesel engine continuously burns the fuel injector. The operator tested the injector on the test bench and found that the atomization was extremely poor. Remove the injector and check that it is difficult to remove the needle valve. After replacing the new nozzle, the pilot found that the fuel injection is like a person sneezing. It is a sudden injection, instead of a continuous “click”, and the atomization quality is not very good. Another injector is replaced, and the injection situation remains the same, so that it is possible to eliminate the problem of the injector. The operator then looked for the cause from the injector body. At this time, he remembered that when he took the old nozzle from the injector cap, the gap was full of coke and the removal was laborious. However, he was ignorant of the clean injector cap that had been cleaned and tightened after disassembly. Then look at the inner hole of the pressure cap fitted with the nozzle and notice that the inner edge near the inner hole has a bright area. It seems that the problem lies here. The original material hardness of the pressure cap is relatively poor, coupled with multiple disassembly, has caused shrinkage. In this way, the fuel nozzle, which is tightly fitted with the pressure cap, receives the high pressure of the pressure cap and the thermal expansion during operation, which causes the needle valve to become stuck and burn in a half-open state. Fourth, the serious rust in the diesel tank A 4125A diesel engine has continuously burned the nozzle. The reason is that the locomotive is parked for a long time, the rust in the diesel tank is serious, and the diesel filter is damaged, so that the rust enters the oil passage and the nozzle is damaged. After the tanker thoroughly cleans the tank and replaces the diesel filter, the nozzle is no longer burned. Fifth, the high-pressure fuel pipe is not clean After a machine operator replaces a new high-pressure fuel pipe, the diesel engine will burn continuously. The reason is that the newly replaced high-pressure fuel pipe has rust in the pipe diameter, and the rust is caused by high-pressure oil flushing into the nozzle. Therefore, when replacing the high-pressure fuel pipe, the high-pressure oil pipe and the high-pressure gas must be used to clean the high-pressure fuel pipe to ensure that the pipe can be installed after it is clean. 6. The top rod is seriously worn out. A 185-type diesel engine is continuously burned. The operator removed the nozzle to check and found that the needle valve was difficult to remove. After that, the hand forceps pull out the needle valve by forceps, and the fuel injector body and the needle valve have a circle of carbon deposit on the mating surface. Obviously, the needle valve is burned to a half-open state and the high-pressure combustion gas rushes into the agglutination. Then remove the injector adjustment screws, springs and jacks for inspection and found that the head of the jack has serious signs of wear. It can be seen that the continuous firing of the nozzle is caused by the extreme wear of the head of the ejector rod, which causes the movement of the ejector rod to deflect. As a result, the operator replaced the new ejector rod so that the ejector rod was concentric with the center hole of the housing. Since then, there has been no continuous firing of the injector nozzle. 7. The injector body failed. A diesel engine burned the fuel nozzle frequently. After inspection by the operator, it was found that the condition of the aircraft was basically the same as in the third case. However, when the new nozzle is installed, there is no phenomenon of pressing the nozzle cap. However, several new nozzles were replaced and tested on the test bench. It was found that the quality of the injection and the quality of atomization were not good. Carefully observe the joint surface between the injector body and the injector, see the two sides of the indentation of different colors, which determine the pressure is not uniform, resulting in deformation of the nozzle cover, resulting in stuck needle valve. In order to avoid misdiagnosis, the pilot also installed a new injector that had just been tried on another injector and found that the injection was very effective. Due to the inability to solve the injector body deflection, the operator had to replace the new injector body. VIII. Lower injector fuel injection pressure A S195 diesel engine has continuously burned the injector nozzle. The operator removed the injector and tested it on the test bench and found that the injection pressure was less than 9800 kPa. The reason is that if the operator finds that the pressure of the fuel injection pump cannot meet the requirements, it will use the method of reducing the injection pressure of the injector to maintain. As a result, the fuel injection pressure is lower than the cylinder pressure, causing the fuel to burn in the injector, resulting in the needle The valve stuck and burned. After the cause was found, the new injector was replaced, and the injector was calibrated to the standard injection pressure. After replacing the new plunger and outlet valve of the injection pump, the fault was completely eliminated.