First, the inspection and judgment of the state of accessories
1. Inspection and judgment of plunger's technical status
(1) Observing method: Observe the traces of the most severe parts of the wear, and use the fingernail to feel a clear feeling when it is stroked horizontally. Replace it with a new one.
(2) Empirical method: Clean the plunger with diesel oil, and fill the sleeve with diesel oil. Use a finger to block the oil inlet hole, oil return hole, and center hole of the plunger and then pull out the plunger. Relax after the length of /3. If you can return immediately, you can continue to use it; otherwise, you should replace it with a new one.
(3) Pressure gauge inspection method: Connect the pressure gauge to the pump head, place the throttle at the maximum fuel supply position, turn on the decompression and crank it so that the plunger will pump oil at a rate of 30 times per minute. The pressure must be greater than 19.6 kPa; otherwise, new ones should be replaced.
2. Checking and judging of the technical state of the oil valve
(1) Observation method: Observe the sealing ring, if it is recessed and its width exceeds 0.5 mm, or if the decompression belt has obvious wear groove marks and the original bright surface cannot be seen, replace the new one.
(2) Oil pressure test method: Remove the high-pressure fuel pipe of the cylinder to be inspected, open the injection pump inspection window, shake the cylinder plunger to the bottom dead center, pump the oil with the hand pump, first eliminate the air in the oil circuit, and then observe There is no leakage at the joint of the high-pressure tubing. If there is leakage, new parts should be replaced (this method can not check the decompression ring).
(3) Pressure gauge inspection method: This inspection should be performed simultaneously with checking the plunger pressure. When the steady value of the pressure gauge pointer is reduced from 19.6 kPa to 17.65 kPa after the oil supply is stopped, the time required is not less than 15
Seconds, indicating that the seal is good; immediately after the pressure is raised to 24.52 kPa, the oil is cut off. Pay attention to the back position of the hands. If it is 0.98-6.87 kPa, the decompression is normal. Only when the seal is good can you see the exact value of the backswing.
If there is still a fault after the above check, the oil valve should be removed and the wear observed after cleaning. If there is no obvious groove marks, the high-voltage copper mat will not wear out. Generally, after cleaning, the seal surface will be studied and tightened tightly to restore normal; otherwise, new parts shall be replaced.
3. Inspection and judgment of the injector's technical status
This inspection should be performed on the premise that the plunger pair and the outlet valve are working properly.
(1) In-vehicle test method: When the other parts of the engine are normal, the fuel injector can be mounted on the vehicle after being coarsely adjusted. When the engine is started, it can be debugged in the car by listening to sound and watching exhaust.
(2) Standard nozzle comparison method: This method uses the normal nozzle adjusted in advance to compare with the injector to be checked. Use a three-way pipe to connect them to the fuel pump in parallel, then drain the air in the oil circuit to put the throttle in the maximum position. Open the decompression cradles and observe whether the two nozzles are in the same condition. If both are injected at the same time, or if they are stopped at the same time, the atomization state is the same, indicating that the injectors being tested are qualified.
(3) Pressure gauge inspection method: Use a tee pipe to connect the pressure gauge and the injector to be checked in parallel with the fuel injection pump, and place the throttle at the maximum position. Turn on the decompression rocker pump oil so that the pressure is expressed to 9.8 kPa (combined with the adjusting pressure regulator spring). The fuel injectors are then sprayed at a rate of about 10 times per minute without driping. After the above work is completed, the needle valve is adjusted to the specified pressure, and then the atomization test is performed at about 80 times per minute. The droplets should be fine and well-distributed, the direction of the oil beam, the cone angle should meet the requirements, and the cut of the oil beam should be crisp and have a special crisp sound.
If there is still a fault after the above check, the needle valve, plunger, and spring shall be removed for cleaning inspection. If it cannot be returned to normal due to serious wear, new parts should be replaced.
Second, to extend the life of the couple
In addition to product quality problems, the root cause of coupling damage is mainly due to improper use of the machine and inaccurate or incorrect maintenance. Let's talk about some measures taken to extend the life of the couplings for reference.
1. Strictly implement the fuel precipitation filtration system. The injected diesel should be collected after 48 hours of precipitation. The diesel used should meet the standard model of the season. Refueling tools should be cleaned exclusively. The areas for refueling and storing oil should also be cleaned so that dirt does not mix with the fuel to accelerate the wear of the coupling and reduce the life of the coupling.
2. Strict technical maintenance and maintenance regulations are formulated. The fuel filter works for 100 hours and the fuel tank works for 500 hours each. If it is found that the damage effect of the filter element is replaced in time, it must not be dismantled and a direct-current fuel supply must be used. Couples shall be disassembled and inspected once 500 hours of working under normal working conditions. In the demolition inspection, ensure that the site, hands, tools and cleaning oil are clean to avoid contamination of the coupling parts. During the disassembling operation, it shall not be tapped indiscriminately. When cleaning, do not dispose of it in a random manner. Do not wash it together with other non-partial parts to avoid bruising or scratches. During assembly, it is not allowed to change the assembly position arbitrarily to achieve certain purposes that do not meet the working requirements of the machine. When installing the oil valve tight seat and the oil nozzle tight cap, tighten according to the specified torque to ensure that the assembled fuel injector and fuel injection pump are in good technical condition.
3, in addition to the above requirements, we should also improve the understanding of dual parts, understand the structural characteristics and working principle of the couple, strengthen and improve the maintenance of the dual parts, operation and use, so that when there is no fault, do not arbitrarily adjust, maintenance use Do not arbitrarily dismantle, maintenance and inspection will not be indiscriminately knocking, cleaning and maintenance does not rub indiscriminately, when the assembly adjustment does not change chaos screw, all in accordance with the specification of technical requirements, in order to achieve the purpose of extending its service life.
