DIESEL AUXILIARY ENGINE NO. 3 / ENGINE FUEL PUMP CONCERN
This document consists of the detection of fuel pump condition issue on unit no. 6 of a Hyundai MAN B&W 7L32/40. High, Raw, Ultra vibration and PV measurements were performed with vibration equipment, the results were analyzed.
The main engine condition is based on the real load calculated by our measuring equipment and vibration an ultrasonic measurements collected. The fuel pump condition is based on the combustion pressure readings taken during the engine operation and vibrations from the pump itself. The data obtained from the engine analysis was processed, analyzed and compiled by a qualified professional analyst, resulting in the following recommendations:
Late peak of fuel pump ultrasonic signal in respect to the combustion curve indicates a major problem with the pump condition.
Fuel pump ultrasonic Vib measurements acquired can be shown as follow:
Ultrasonic vibrations peak on the Fuel pump of unit 6 is observed, later on the remaining units. As a conclusion of this analysis, it was recommended to check the Fuel pump condition on this unit.
Fuel pump ultrasonic Vib measurements acquired with respect to the combustion curve can be shown as follows:
Ultrasonic signal with respect to the combustion curve. Peak signal is achieved significantly after TDC of this unit. This ensures the analysist in that the recommendation is correct.
Power parade shows that unit no 6 has an issue with the fuel pump condition.
The engine was stopped and cooled down, then the Fuel pump no 6 cap was disassembled, cleaned, measured and tested. The Fuel pump was in very bad condition therefore the crew installed a new one.
After the adjustment was made the engine was restarted and new vibration measurements of fuel pumps were taken. The results can be shown as follow:
It is clearly shown that after the adjustment the fuel pumps are operating at the same moment.
If no actions where performed a serious damage could put this engine out of order for a long period of time.
Main bearings no 5 and 6 Hi Freq Vib signals are much stronger than on the other main bearings. As a conclusion of this analysis, it was recommended to perform the crankshaft deflection measurement.
5. SHIP ENGINEERS CHECKS
The engine has been shut down and left to cool down. Then the crankshaft covers were dismantled to access the crankshaft. The deflection measurement was found to be over the limit. For this type of engine crankshaft measurement readings should be between 0,02[mm] and 0,10 [mm]. The crew decided that the main bearings will be changed on the next drydock due to a lack of spare main bearings on board.
6. CONCLUSIONS
It can be concluded that the diagnosis obtained from the measurements and the data analysis was correct. The crew was informed to reduce the load on the engine to 50%. New vibration measurements will be performed after the main bearings no 5 and 6 are replaced.