Disassembly method of Fuel Injector:
1. Because the Diesel Engine Injector is in the high temperature and high pressure gas impact environment for a long time, the carbon corrosion is more serious, and the cylinder disassembly is more difficult. Some machine operators simple operation method, often cause screw bite, nut cracking, and even cause parts damage or fuel injector scrap. The correct method of disassembly is: After removing the pipeline and other joints, clean the injector and cylinder head with kerosene, or spray a small amount of bolt loosening agent, and then use the copper rod along the radial direction to knock the injector in the left and right direction, so that the injector rotates, and then use the hammer to knock while crowbar, pay attention to the crowbar head in the injector ear, if the support in the oil inlet, should be on the soft materials such as copper skin, to prevent damage to the injector thread. 2. For fuel injectors with conical pads, such as 105 series and 6120 series diesel fuel injectors, the conical pad should be removed before loosening the fuel injector cover to avoid the fuel injector needle valve. When the body is clamped by the conical pad, it tightly rotates with the fuel injector cover, resulting in the fracture of the positioning pin of the fuel injector body, and even the misalignment of the positioning hole of the fuel injector body and the fuel injector body cracking. For injectors with dowel pins on the housing, such as tin diesel 110 series diesel engines, turn off the injection pressure regulating screw before loosening the injector cover to prevent the nozzle assembly spring from pressing on the nozzle. Under the action of external movement, the dowel pins produce a lot of torque, which causes the dowel pins to break, and even the pin holes to split. The remaining part of the dowel pin is sometimes difficult to remove from the dowel hole in the injector body. In this case, it is often necessary to install only one dowel pin or no dowel pin. In general, in non-emergency situations, the body of the injection needle should not be equipped with only one dowel pin. Since only one dowel pin is installed and the injector cap is tightened, the injector needle body may rotate around the dowel pin, making the injector needle valve easily misaligned with the injector housing tappet hole. Once misaligned, the force of the nozzle tappet acting on the needle valve stem is easy to produce a certain radial component. The needle valve is easily blocked when moving up and down in the needle valve body. While debugging, you may barely survive, but the potential pitfalls should not be ignored. In severe cases, the needle valve moves up and down in the needle body. It may drip during debugging. If the needle valve body is not slotted, there may be a large dislocation between the injection needle body oil hole and the injector shell oil hole when the positioning pin is not installed. Although the diesel combustion will not be affected, the small cross-sectional area of the oil hole will have a certain impact on the amount of oil injection. 3. The surface roughness of the injection pressure adjustment screw locking nut is different on both sides. For example, in the fuel injectors of 4125 series diesel engines, a surface with less surface roughness should be installed on the fuel injectors housing. This effective contact area is large, the braking effect is good, the ability to prevent screw loosening is strong, the lock is reliable. 4. The metal rod seam filter element (such as 135 series diesel engine) and metal spring seam filter element (such as Tiandong 146 series diesel engine) in the oil injector needle body ring inlet should be thoroughly cleaned, do not clean and remove. Practice has proved that the filter element has certain effect on preventing mechanical impurities from entering the coupling, prolonging the service life of the coupling and preventing the needle valve pad. 5, for the fuel injector nozzle lift adjustment screw, such as 146 series diesel fuel injector, the lift adjustment screw should be screwed off before the installation of the fuel injector assembly, so as not to tighten the fuel injector assembly. When the bottle cap is tight, the needle valve lift adjustment screws and other parts are deformed. In addition, when the nozzle assembly is installed in the injector cap, the notch on the needle body flange of the injector must be aligned with the positioning pin on the cap, and the injector plate and valve body must not be removed. 6. For porous, slender, porous nozzle assemblies with assembly markings, the markings must line up the markings on the injector needle body with the markings on the injector housing. When the alternative is not marked, the nozzle can generally be assembled at the higher position of the nozzle, and the positive pressure injector inlet joint can be treated. It is also possible to test the signed nozzle assembly on the injector tester, note the injection position of each hole, and assemble unmarked connections. 7. The contact surface between the oil injector shell and the oil injector body should be smooth, clean, without carbon accumulation and scratches. Clean up when Coke is available. When there are scratches, the light ones should be grinding, and the heavy ones should be grinding after grinding on the surface grinder (note: the deviation between the plane perpendicularity and the center line of the thread must meet the technical requirements). 8. Check the copper cone or gasket before installing the injector assembly on the cylinder head. If the deformation is too large or there is other damage, should be replaced and clean the injector seat hole surface, remove carbon and other impurities. Make sure everything is airtight. When the injector is reinstalled in the orifice, it is important to note that the positioning slot on the fixed platen must be aligned with the positives injector positioning pin. Tighten the two fixing bolts with even force and the same tightening torque. After tightening, check the protrusion of the lower cone of the nozzle body in the copper cone (generally 0.3mm), and the size of the cylinder head of the nozzle body tip in the lower plane (generally 0.15-0.85mm) in accordance with the regulations. In order to avoid the needle valve and nozzle body temperature rise, reduce the power and economy of diesel engine. When the above protrusion does not meet the requirements, the adjustment pad above the copper cone (or gasket) should be increased or decreased, or the copper cone (or gasket) should be replaced for adjustment. The inspection and adjustment of the above protruding amount is a maintenance item after the injector and cylinder head are removed from the diesel engine at the same time. If the injector is only removed for maintenance, attention should be paid to each injector when assembling, and the copper cone (or gasket) and adjusting pad above it should not be installed incorrectly to ensure that the taper and tip elongation of the nozzle body meet the requirements. The inspection and adjustment of the above protruding amount is a maintenance item after the injector and cylinder head are removed from the diesel engine at the same time.
