【故障】船舶发电机故障解决案例分析（DAIHUTSU DIESEL ENGINE 8-DK28C）
Fault analysis and treatment report of Engine Driven C.W. Pump(SYSTEM OIL FEEDED TYPE)
Engine type:DAIHUTSU DIESEL ENGINE 8-DK28C
Generator power : 4 sets x 3000kw/set
A.E. condition was belows since I joined this vessel:
No.2 A.E. Stopped for waiting the spare parts(engine driven F.W. cooling pump's casing).
The exh. Gas Temp.' difference of each Cylinder unit of the other running A.E. units。 (No.1,3,4) was found too high (70-150ºc) .
The T/C. L.O. low press. Alarm of the running engines was happened once and again.
The engine load was kept below 1500-1600kw always. If exceed, the inlet exh. Gas temp. of T/C.will overlimit(580ºc), the exh. Gas Temp. of each units was also above 480ºc.
The crew members were effort to top overhaul if they found the exh. Temp.of any unit abnormal high .
The auto-start remote control function of all A.E. was found lost.
The black out case was happened for 10 times in the last 3 months.
NO.1 A.E.
mm-dd-yy: NO.8 UNIT'S CYL.HEAD of No.1 A.E. was replaced with recond. Spare for the exh. Gas temp.abnormal higher due.The condition of the combustion space as above photo shows. I doubt it might be caused by the poor condition of the F.O. injector.The fuel v/v. injection starting pressure was found only 250 kg/cm²(normal standard:350kg/cm²)after testing.
(The pressure gauge of the fuel v/v. test stand was replaced with a calibrated gauge before.)
All recond. Spares of F.O. injectors were been tested firstly and found the opening pressure was 250-300kg/cm²,then readjusted to standard value.
All F.O. injectors of No.1 A.E.had been replaced with recond. Spares, the opening pressure of the used F.O.v/v.s were been tested and found only between 250-280kg/cm². The power balance of all units checked and readjusted by the means of the adjustment of fuel pumps. The auto-start remote control function has been resumed after that.
NO.3,4 A.E.
The actual condition of all unit's F.O. injectors was been found same as No.1 A.E.'s and replaced with Recond. Spares.
The below jobs have been done since I found the root cause:
1. All F.O. injectors of No.1,3,4 A.E. have been replaced with recond spares.
2. No.1,4,5,8 unit's fuel oil pumps of No.3 A.E. have been replaced with recond. Spares.
3. No.3 A.E's turbine & blower side has been opened up & water-washed due to T/C surging while the engine load over 1500kw.
4. The auto-start function of No.1,3,4 A.E has been resumed.
5. No.1 &2 A.E. L.O. purifier's heater has been dismantled for cleaning, the inlet temp. of lub. Oil purifier was already increased from 68ºc to 85-90ºc now.
6. No.3 A.E. all units' exh. Gas temp. gauges have been renewed and all temp. sensor have been calibriated.
7. No.4,5 cyl. heads of No.3 A.E. have been replaced with recond. Spares because I doubt that the exh. v/v.s already burnt out.
The follow jobs had been carried out in next step:
1. At least 50% gas temp. gauges of A.E. found in bad condition, its will be replaced in first.
2. the performance of all gas temp. sensor disbelieved , its will be calibriated.
3. 6 pcs of used cyl. Head and many used fuel oil pumps were kept in workshop since I joined vessel,its need to be reconditioned as soon as.
4. A few of unit's cyl. Heads in used need to be replaced due to some exh. Gas V/V. might be damaged.
5. No.1,4 A.E. T/C.'s terbine &blower side shall be opened up for inspection and cleaning。
6. As for No.2 A.E.'s resume condition, the driving gear and the other parts will be reassemblied soon,but I think that it's the most important to keep the other 3 sets of A.E in normal using condition firstly in this period.
7. The cooling fan's bearings of shaft generator should be inspected due to S/G has been stopped since the end of last year, I want to put it in running under appropriate sea speed after inspection.
8. The D/G.'s crankcase will be thoroughly cleaned while the oil refreshed.
9. The F.O. viscosity auto control devices for M/E & A.E. were been found out of serive ,the F.O. inlet Temp. of M/E & A.E. was always kept at 130 ºc & 131 ºc before, I was already readjusted its to 138-141ºc(about 12cst)by manual. The disabled control device will be repaired and resumed soon.
Below is my analysis about A.E. serious malfunction happened since the early of this year as my observation :
The engineer was unaware of the pressure gauge of the fuel v/v. test stand already failure
The fuel v/v. injection starting pressure was been wrong setted and fitted into engine as spare
A/E. all units ' fire timing wrong earlier; the engine F.O. inlet temp.& viscosity was lost control
1. 2.
1.engine performance worsen, the engineer should adjusted the fuel pump's setting for improve the unit's output power and keep the balance of each unit's exh. Gas temp.
2.the combustion residue will increase and the system lub oil been polluted.
Some exh. Gas temp. Gauges locate engine side Some exh. Gas temp. Gauges locate engine side。
The exh. Gas Temp.' difference of all units falled into confusion, the engineer have to adjust the fuel pump setting again and again!!!
engine performance was more worsen
For precaution against troubles, the follow procedures have been shaped:
1. Engineers must check the running pump's condition by 2 pcs of newly made listening gear
2. Every 1000 running hours intervals,the bottom bull plug must be dismantlied and flush the oil sump through the upper bull plug with fresh lub oil while the engine is stopping, and then pour the fresh oil (1.5 ltrs) through the upper bull plug hole.
3. A.E. lub oil purifier must keep run continuously and the lub oil temp before purifier must be kept above 85ºc.
Best Regards!
C/E Mu Xin