The experimental results on the combustion and wear of two cracked types high viscous marine fuels; a fluid catalytic cracked bottom based oil and a visbreaker bottom based oil, in a marine low speed diesel engine are summarized as follows:
(1) Two fuels are made possible to burn with heating and treatment of impurities, and to out pour the rated output in a marine low speed diesel engine. But the specific fuel consumption increases, the mechanical efficiency and the brake thermal efficiency decrease.
(2) The angle of the pressure increasing in the combustion chamber is deduced and the burning time is long as compared with using diesel oil.
(3) The mean wear rates of the cylinder liners and piston rings are largest in the using fluid catalytic cracked bottom based oil. The rates of feeding the low alkalinity cylinder oil is larger than the high alkalinity cylinder oil, the rates of the titanium vanadium liner is little difference with it of the high phosphorous liner.
(4) The ash of the deposite on the surface of the piston crown in the combustion chamber contains 9.3% (wt) silicon particles, its size is 30-50μm, is one of the catalitic metal particles. The other hand, aluminium particles does not contains scarecely.
These experimental results suggest that, in the burning of the fluid catalytic cracked bottom based oil, the silicon particles in the combustion gas are mixed in the sliding surface between cylinder liner and piston rings, the so called, it is abrasive wear, and the wear rates become large.