Diesel Injector Fuel Injector Lr006496 A2c59513553 7h2q9K546CB 7h2q-9K546-CB for Land Rover 276dt Siemens Injector

1. Fault phenomenon

Poor atomization of the fuel injector (injection into thin lines or post-dripping) The external manifestation is that the temperature of the diesel engine is high and the work is weak. The upper part of the cylinder has a knocking sound. The exhaust pipe emits black smoke. sound

2 failure reasons

From the above, it can be seen that the poor atomization of the injector is mostly caused by the pressure of the fuel entering the annular oil chamber of the injector being lower than the starting injection pressure specified in the technical documents and the viscosity of the fuel being too high. The main reasons are (1) Improper installation of the fuel injector or the surface of the precision coupling is dirty or there is gas back leakage, causing the fuel injector to overheat and cause poor atomization of the fuel injector (2) The technical condition of the fuel injector. All indicators of the fuel oil meet the requirements. If the fuel atomization of the fuel injector is poor, it is mostly caused by the deterioration of the technical condition of the fuel injector. (3) The pressure regulating spring of the fuel injector is too small. It can be seen that the fuel pressure in the annular oil chamber of the injector changes with the pre-tightening force set by the pressure regulating spring. If the pre-tightening force set by the pressure regulating spring is too small, the fuel pressure in the annular oil chamber will also be small. The density of fuel molecules is relatively small and the pressure has not continued to increase. The density of fuel molecules has not yet reached the ideal density during injection. The needle valve is pushed open by the fuel and the fuel is injected because the density of fuel molecules is not high, so the expansion and diffusion energy of the fuel sprayed out of the injector body is small. That is, the atomization is poor (4) The fuel injector is not closed tightly. When the fuel injector is working, the needle valve and the valve seat will vibrate, which will cause fatigue cracks on the working surface of the needle valve and delamination deformation. In addition, there are mechanical impurities, hydraulic flow erosion and Corrosion and other influences reduce the roughness of the working surface of the needle valve and the valve seat, and the sealing performance becomes poor and oil leaks, which affects the increase of fuel pressure in the annular oil chamber and the inability to increase the density of fuel molecules, resulting in poor atomization.