To eliminate the rust formation and restarting failure of an engine caused by water-added fuel oil.
Engine output data serving as the functions of output torque, fuel flow, air charging pressure and engine speed is stored in a first storage means 7, and engine output data serving as the functions of fuel rack quantity and fuel injection pressure during operation with water-added fuel oil is stored in a second storage means 7. A computing means 7 receiving a stop command signal S1 stops a water adding device 13 and computes engine output referring to the data of the first storage means on the basis of output torque, fuel flow, air charging pressure and engine speed detected in subsequent operation supplied with only fuel oil. An authorization control means 7 obtains the fuel rack quantity and fuel injection pressure corresponding to engine output in water-unadded fuel oil operation equal to the engine output computed by the computing means, from the data of the second storage means, compares the obtained data value with the measured value and outputs an engine stop authorization signal S2 when any measured value decreases to reach the data value.
YAMADA TETSUTSUGU
TANABE KENJI
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