The main features of the new FO・LO system are as follows. (1) FO sludge is consisted of solid cores and FO around them. Density of a sludge particle consisted of the core and FO around it is nearly equal to FO density. Accordingly, it is very difficult to seperate FO sludge from FO with cenfrifugal separator. In order to break FO sludge into cores and FO, a sludge breaker is set before the FO service tank as is shown in Fig.6(b). (2) As shown in Fig.6 (a), FO is usually feeded to engines from the bottom of FO tank where there is more contaminant. In order to feed cleaner FO from the upper part of FO tank, a high suction float is equipped with as shown in Fig.6 (b). (3) A fire ring is set between the piston and the cylinder liner to prevent gas blow-by into the crank case and to keep LO from being contaminated, and (4) The kidney system is equipped with in LO system.
Fig. 6 FO service tank
The cogeneration diesel engine of the advanced FO・LO system was continuously run for one year of 8000 hour and it was overhauled for a full check on December 31, 1998. The results were as follows. (1) FO became much cleaner by using the sludge breaker, (2) There were no troubles at all during the running, (3) As shown in Fig.7 and Fig. 8, the crank case was very clean and the crank pin metals were also very clean without any damages or scratches on the metal surface. Also, the FO tank with the floating high suction, the pistons, the cylinder liners and all the other engine parts of LO system were very clean. This was because FO and LO were kept much cleaner in the engine of the advanced FO・ LO system than in the engine of the conventional system. (4) Initial high performance of the exhaust gas turbocharger was maintained during the whole running period, (5) LO consumption was reduced to about 1/10 and (6) Wear rate of the cylinder liner and the crank pin journal also decreased due to the LO cleanliness.
