Fuel supply control device for diesel engine

A diesel engine fuel supply control device which mixes petroleum-based fuel oil and unpurified waste oil and supplies mixed oil thus produced to a diesel engine as fuel thereof, the diesel engine fuel supply control device comprising:

• a first fuel tank for storing the waste oil;
• a second fuel tank for storing the petroleum-based fuel oil;
• fuel mixing means for mixing the waste oil and the petroleum-based fuel oil;
• waste oil quantity regulating means for regulating an amount of the waste oil supplied from the first fuel tank to the fuel mixing means;
• petroleum-based fuel oil quantity regulating means for regulating an amount of the petroleum-based fuel oil supplied from the second fuel tank to the fuel mixing means;
• fuel supply means for supplying the mixed oil mixed by the fuel mixing means to the diesel engine;
• engine speed sensing means for detecting a speed of the diesel engine;
• engine speed fluctuation calculating means for calculating the amount of fluctuation in the detected engine speed with respect to a target engine speed of the diesel engine;
• engine speed fluctuation determination means which determines that an amount of engine speed fluctuation represents first fluctuation amount determination information when the amount of engine speed fluctuation calculated by the engine speed fluctuation calculating means has a value smaller than a first set value, determines that the amount of engine speed fluctuation represents second fluctuation amount determination information when the amount of engine speed fluctuation falls within a range in which the amount of engine speed fluctuation is equal to or larger than the first set value but less than a predefined second set value which is larger than the first set value, and determines that the amount of engine speed fluctuation represents third fluctuation amount determination information when the amount of engine speed fluctuation calculated by the engine speed fluctuation calculating means matches the second set value;
• operating state determination means which determines that a state in which the diesel engine is run in accordance with the first fluctuation amount determination information is a first operating state, determines that a state in which the diesel engine is run in accordance with the second fluctuation amount determination information is a second operating state, and determines that a state in which the diesel engine is run in accordance with the third fluctuation amount determination information is a third operating state;
• mixing ratio setting means for setting a ratio of mixing the waste oil and the petroleum-based fuel oil in accordance with the first, second and third operating states on the basis of individual pieces of fluctuation amount determination information fed from the engine speed fluctuation determination means;
• and
• first control means for regulating the amount of the waste oil supplied from the first fuel tank to the fuel mixing means and the amount of the petroleum-based fuel oil supplied from the second fuel tank to the fuel mixing means by controlling the waste oil quantity regulating means and the petroleum-based fuel oil quantity regulating means on the basis of the mixing ratio set by the mixing ratio setting means.