Once the excavator encounters problems such as difficulty in starting, slowing down, and sudden increase in fuel consumption, many times the maintenance master will start with the inspection and cleaning of the fuel injection nozzle, which also explains the importance of the fuel injection nozzle from the side.
Today, the editor will give you a detailed introduction to the injection inspection, pressure and other related issues of the fuel injector. After mastering the inspection skills, many faults can actually be handled by themselves!
Ready to work
Because the pressure and status of the injection cannot be accurately controlled, it is recommended that you prepare protective glasses, and do not try to test the injection hole with your hands to prevent it from being sprayed on the face, eyes and other parts.
Injection pressure measurement
After cleaning the carbon deposits in the nozzle hole, make sure that there is no dust and other pollutants around, and then the spray pressure can be measured.
(1) Connect the fuel injection valve to the high-pressure pipe of the fuel injector tester.
(2) Slowly operate the operating lever of the fuel injector detector to read the instantaneous pressure when the fuel starts to be injected from the fuel injector.
(3) If the measured injection pressure is lower than the specified value, the pressure adjustment gasket must be replaced with a thick adjustment gasket.
(4) Check the spray status. After adjusting the pressure to the specified valve opening pressure, check the spray status and the oil tightness of the valve seat with a fuel injector tester.
Oil tightness inspection of valve seat
· After spraying 2 or 3 times, slowly increase the pressure and keep it at a pressure lower than the valve opening pressure by 2.0 MPa (20kgf/cm 2) for 5 seconds, and confirm that no oil drops fall from the tip of the fuel injector.
· Use the fuel injector tester to spray while checking whether there is a lot of oil leaking from the overflow joint. If there is a lot of oil leaking, it needs to be tightened again to confirm. When there is a lot of oil leakage, replace the fuel injection nozzle assembly.
Spray and spray state
· Operate the control lever of the injector tester at a speed of 1 to 2 times per second to check whether there is an abnormal injection. If the following normal spray conditions cannot be achieved, replacement is required.
· There should be no extreme tilt. (θ)
· The spray angle should be neither too large nor too small. (α)
· The whole spray should be fine mist.
Good spray stop performance (no drag and water)
Nozzle valve sliding test
Before doing the sliding experiment, clean the nozzle valve with clean fuel, place the nozzle housing vertically, and then put the nozzle valve into the nozzle housing about 1/3 of the length. It is good to observe that the nozzle valve will drop smoothly under its own weight. .
Also, after the new product injector is dipped in anti-rust oil, the film seal anti-rust agent keeps it from the air, so the film seal anti-rust agent should be removed and then immersed in clean new oil to clean the inside and outside of the injector. , It can be used after removing the anti-rust oil.
Post time: Oct-15-2021