Q：Injector failure

A：The injector faults are as follows:

1. The atomization of the fuel injector is poor, and the fault phenomenon is that the power of the diesel engine is reduced, the exhaust smoke is black, and the noise of the machine is abnormal. Fault analysis: when the injection pressure is too low, the nozzle is worn with carbon deposit, the spring end face is worn or the elasticity is reduced, the fuel injector will be opened in advance and closed in delay, and the phenomenon of poor atomization will be formed. In addition, because the diesel droplet with too large particle size can not fully burn, it flows into the oil pan along the cylinder wall, which increases the oil level, reduces the viscosity, and deteriorates the lubrication, and may also cause the accident of burning and pulling the cylinder;

2. The needle valve is stuck, and the fault phenomenon: the engine power drops, shakes, and even fails to start. Fault analysis: the water or acidic substances in the diesel fuel will cause the needle valve to rust and be stuck. After the sealing cone of the needle valve is damaged, the combustible gas in the cylinder will also flow into the mating surface to form carbon deposits, which will cause the needle valve to bite, and the injector will lose its injection effect, causing the cylinder to stop working;

3. The fuel injector drips oil, and the fault phenomenon: when the temperature of the diesel engine is low, it is difficult to start, and the exhaust pipe emits white smoke, and the diesel engine becomes black smoke when the temperature rises. And the fuel consumption is high. Fault analysis: when the fuel injector is working, the sealing cone of the needle valve body will be frequently and forcefully impacted by the needle valve, and the high-pressure fuel will be continuously ejected from this place, the cone will gradually appear wear or spots, which will cause the fuel injector to drip. When the temperature of the diesel engine is low, the exhaust pipe emits white smoke, and when the temperature of the diesel engine rises, it becomes black smoke. Check whether the movement of the needle valve is flexible, the conical surface should be free of wear and sealing, otherwise, it is necessary to replace a new nozzle coupling;

4. The return oil quantity is too high, and the fault phenomenon is that the fuel injection pressure is reduced, the fuel injection time is delayed, the engine power is reduced, and even the diesel engine flameout is caused. Fault analysis: When the needle valve coupling is seriously worn or the needle valve body and the injector housing are not closely matched, the fuel return volume of the injector will increase significantly. At the same time, it is also necessary to pay attention to the valve plate. Once worn, the fuel return volume of the injector will also be too large, affecting the engine performance.