Failure Analysis of High Pressure Diesel Engine Without Pumping Oil in Diesel Engine

High-pressure diesel pump is the core of diesel engine components, once the failure will inevitably affect the normal operation of the engine. In this paper, diesel engine high-pressure diesel pump without oil supply were analyzed in detail, explained the mechanism of the fault, derived the cause of the fault, and gives the method of judgment and disposal. High-pressure diesel pump does not supply oil Failure Analysis High-pressure diesel pump is the diesel engine's "heart" components, in the course of the event of failure, will affect the normal operation of the engine. Among them, high-pressure diesel pump is not a pump of oil is a common failure. This article focuses on the reasons for the failure, and gives analysis and judgment methods. High-pressure diesel pump is not oil, essentially refers to the high-pressure diesel pump can not supply fuel to the engine cylinder. From the point of view of use, high-pressure diesel pump can not supply oil to the engine in general, there are two situations: one is the main oil duct of the high-pressure diesel pump has air; the other is the high-pressure diesel pump itself mechanical failure. First, the oil inlet 1 common cause of diesel intake air parked engine long-term parking because of the high-pressure diesel pump main oil in the main passage through the plunger and plunger Jane gap leakage into the bottom of the high-pressure diesel pump to produce low pressure, or oil pump After some of the oil circuit is not closed, due to leakage caused by low pressure within the oil passage, the outside air will enter the oil by the non-closed place, and gradually brought together to the main oil pressure of high-pressure diesel pump. When there is air in the main gallery, air enters the plunger to form bubbles. When the plunger goes up, the bubble is compressed and the volume becomes smaller, so that the hydraulic pressure in the high-pressure tubing can not be raised to the pressure required for injection and can not be injected; when the plunger expands downwardly to recover the original volume, the plunger Cavity can not produce enough suction, diesel can not enter the plunger barrel, this phenomenon, commonly known as "air resistance", resulting in the engine can not start. When the engine is started, the oil in the oil circuit behind the oil pump is always higher than the atmospheric pressure due to continuous oil supply from the oil pump. Therefore, the air can not enter the oil channel, and can only leak oil from the unsealed point. When the engine stops working, it never closed into the air. In summary, the cause of the diesel pump inlet air can be summarized as follows: (1) high pressure diesel pump plunger barrel set screw loosening or gasket damage. (2) high-pressure diesel pump inlet pipe connector loose or improper installation. (3) High-pressure diesel pump to exclude air pipe joints (bolts) loose or gasket damage (4) After the oil pump pipe fittings loose, the pipeline is not closed and the air inhaled. 2 Judgment and exclusion When the high-pressure diesel pump air, should identify the air intake. And completely ruled out. When the engine is working, the oil will be leaking out from the non-confined place, so the confiscated place should be found out based on the oil trace. Long-term parked engine, the general should be excluded before starting high-pressure diesel pump air. After exhausting the engine still can not start, then the air has entered the high-pressure oil. At this point should press the start button for a longer time and suddenly increase the throttle, start the engine, so a few consecutive starts, you can rule out the high-pressure oil in the air, so that the engine start smoothly. Second, refueling gear rod stuck in the stop position for a common cause (1) gear pole embroidered. For long-term parking of vehicles (especially in open-air parking lot parked vehicles) or dehydration of the oil seal high-pressure diesel spring rusty. (2) individual plunger return spring broken. Return spring at work, to withstand regular high-frequency repetitive dynamic load. Large force, easy to produce fatigue break. Broken spring break if caught in the gap between the drum and the pump body, the gear rod stuck. (3) rack bar limit bolt loose. When the gear rod stopper bolts loose, the gear rod loses the limit point, so that the gear rod and the ring gear can not be normal engagement, which will work at the moment due to vibration and inertia suddenly reduced oil, the ring gear and gear Sudden changes in meshing backlash, top gear phenomenon may occur diesel pump. Stuck the gear rod.