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Why Would 4 Stroke Diesel Engine Not Supply Oil?

Views: 67     Author: Site Editor     Publish Time: 2020-06-25      Origin: Site

Why Would 4 Stroke Diesel Engine Not Supply Oil?

Why 4 Stroke Diesel Engine Does Not Supply Oil?

A data center acquired an 800KW imported water cooled new motor turbocharge diesel engine set. The engine of this unit is 12V, with 6 cylinders on each side. The oil is supplied by two high-pressure oil pumps. It was only used as a backup power source for the data center. The actual operation lacked 800h.


In the fifth year, due to the overhaul of the city power, the protection department made preparations for the start of the standby KPV780 441kw 12 cylinder diesel engine 2 days in advance. The test operation was normal, but after 1-hour use, the generator set had an abnormal screaming sound, between the left exhaust manifold and the turbocharger, it became hot and red after a heavy load, the body had a significant sensation, the exhaust pipe emitted black smoke when the load was started, and the operator stopped immediately. The power supply in the data center was extremely urgent. In addition, the city power would be cut off for two days. UPS could not satisfy such a long-term power supply. If the fault could not be eliminated in time, the entire data center would be paralyzed. If let the technicians come to repair, it would take at least two days. The person in charge of data center protection immediately arranged relevant technical personnel for consultation, and based on the fault phenomenon, analyzed the possible causes of the fault.



1. Malfunction Analysis

If the muffler is blocked or the turbocharger is defective, the exhaust will not be smooth, which may result in high temperature of the exhaust pipe. Remove the upper part of the turbocharger outlet at the same time, look at the exhaust pipe and muffler on both sides, and quietly move the blades of the turbine by hand. The turbine on the right is easy to operate, and the left turbine has some resistance compared to the right, but still can scroll freely. The generator set was started immediately. Although the temperature of the bronchus and turbocharger was relatively high after ten minutes of idle operation, it did not become red. Since it has an impact on the turbocharger, in order to eliminate the problem, the mixing station was opened to add load to the generator set, and there was a lack of 10 minutes. The exhaust pipe and turbocharger showed high temperature redness again, after unloading the generator set, the red exhaust pipe gradually became darker, which shows that the turbine and muffler were operating normally. The redness of the exhaust pipe and turbocharger was related to the load of the generator set.


Installed the muffler and exhaust pipe from the beginning, and started the generator set, carefully observed the exhaust volume of the exhaust pipe, and felt whether the exhaust volume and temperature are the same at the two exhaust ports. The results found that the exhaust temperature and exhaust pressure of the right exhaust pipe port were low, and the exhaust volume was also small, the exhaust pressure, exhaust temperature and exhaust volume of the left exhaust pipe port were high. According to the exhaust pressure, exhaust volume and exhaust temperature of the two exhaust pipes, it could be estimated, either the fault of the electronic governor or the lack of fuel supply caused by the fault of the high-pressure pump, or the individual cylinders not working or some cylinders not working.



2. Trouble Shooting

First, started the generator set, checked the electronic governor. Opened the right governor end hole, took out the top block, used needle-nose pliers to hold the rack while the 1800rpm powerful 12 cylinder diesel engine is operating, and pulled it out. The engine should be turned off or the sound changed. The results did not respond, which shows that the governor working is outstanding.


Second, checked whether there is high-pressure oil overflow at the outlet of the high-pressure oil pump, and the results surprised all the people, none of the six cylinders supplied oil. First shut down and removed the power cable of the oil supply solenoid valve, and then connected a power cable from the battery. From the sound of the solenoid valve spool, it could be judged that the solenoid valve was operating normally. Removed the oil pump inlet, because the oil supply tank was relatively high, and the oil pipe had a certain pressure of oil. From this, it could be known that either the high-pressure oil pump plunger was stuck or the oil pump was damaged. If the plunger of the high-pressure oil pump was stuck, the rack that controls the oil supply of the plunger cannot be pulled. It had been seen that the rack can be pulled, which shows that the reason why the six cylinders do not supply oil is the fault of the fuel pump.


In order to maintain the power supply continuously, the repair personnel used the tension spring on the fuel pump of the high quality 660kw 4 stroke diesel engine to temporarily replace it, and added gaskets to adjust the tension spring pressure, and started the generator set from the beginning. According to the above process, all the abnormal phenomena disappeared.


According to the analysis, the real reason for the high temperature redness of the exhaust branch pipe and turbine of the generator set was: due to the fault of the fuel pump, the 6 cylinders on the right were not working, only the 6 cylinders on the left were working, the electricity generated was only 400kW. It can basically maintain its normal operation under no load or small load, but under heavy load (the installed power of the mixing station is 560kW), it is difficult to pull the asphalt mixing station, it will output more power with the increase of the external load, the overload operation leads to the addition of fuel, displacement and high temperature of the high speed 1800rpm 6 cylinder diesel engine, which causes the temperature of the exhaust pipe and turbocharger to be too high, and then it becomes red.

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