Fig. 2 Distribution of distillation temperature of test fuel oil
Fig. 3 Outline of fuel injection system
In the figure, the shadowed part of BFO means the residues in the refining process of crude oil, which has the boiling point of not less than 500℃ under the atmospheric pressure. In the injection, GO was injected at the normal temperature and BFO was heated to 105℃ so that the viscosity at the inlet of the fuel injection valve is 20 cSt.
Fig. 3 shows the outline of the fuel injection system. Because BFO is not fluidized at normal temperature, the BFO in the measuring tank was heated to about 85℃ once, and circulated by the pump so that the pressure at the inlet of the engine was adjusted about 0.2 Mpa by the pressure regulating valve. In addition, the piping part was heated by the flexible heater to raise the oil temperature to 105℃. The fuel consumption was calculated by measuring the time in consuming the fuel of 300 g.
In the experiment, the load factor was set to 75% (2180 rpm) of the marine characteristic at the normal injection timing (15℃ before the top dead center), and the measurement was performed with GO. Then, the fuel change-over valve was switched to BFO. After the complete changing of the fuel was confirmed (in the operation for about 15 minutes), similar measurement was performed with BFO. Then, the fuel was again changed to GO, and the engine was stopped.
