1) The amount of lubricating oil in the oil pan is insufficient or the oil circuit is not smooth, the oil pump cannot supply oil normally, or the lubricating oil pressure is too low, resulting in poor lubrication.
2) The grade of lubricating oil does not meet the requirements, the lubricating oil has deteriorated and is too dirty; the waterproof rubber sealing ring of the cylinder liner fails, causing the cooling water to leak into the oil pan.
3) The gap between the journal and the bearing shell does not meet the standard. The gap affects the formation of the lubricating oil film; if the gap is too small, the lubricating oil will not easily enter the friction surface of the journal and the bearing bush, and the lubricating oil film cannot be formed; if the gap is too large, the vibration and impact between the journal and the bearing bush will increase, causing the lubricating oil film to rupture .
4) The diesel engine has just started, especially in winter, when the lubricating oil has not been fully lubricated, it should be operated at a high speed and full load, or frequently started, idling for a long time, etc.
5) Long-term overload and over-speed operation of diesel engine: the temperature of the body is high, the viscosity of the lubricating oil is reduced, and it is difficult to form a normal lubricating oil film; the alternating load and the number of cycles of action exceed the limit of the bearing material; the fluctuation of the load or the increase of the fluctuation range makes lubrication The oil bubbles burst.
6) Improper use, maintenance and assembly, flashing on the journal surface, and failure to clean during assembly.
While troubleshooting the machine itself, pay special attention to finding and analyzing the cause of the failure. For example, the failure of the bearing bush is caused by low lubricating oil pressure, lack of lubricating oil, or dirty blockage in the oil passage, poor oil flow, etc. , Only after finding the final cause of the failure and eliminating it, can the diesel engine work reliably, so as to avoid the occurrence of similar failures again after the bearing bush is replaced.
Post time: Jul-29-2021