Engine control device and engine control method

An engine control device comprising:

• a variable displacement hydraulic pump driven by an engine;
• a hydraulic actuator driven by a discharge pressure oil from the hydraulic pump;
• a control valve that controls the discharge pressure oil from the hydraulic pump so that the discharge pressure oil is supplied to the hydraulic actuator;
• a detector that detects a pump displacement of the hydraulic pump and an engine torque;
• a fuel injection device that controls a fuel supplied to the engine;
• a fuel dial that selects one of variable command values and commands a target engine speed to the engine;
• a first setting unit that sets a first target engine speed according to the command value selected by the fuel dial and a second target engine speed based on the first target engine speed, the second target engine speed being lower than the first target engine speed by a predetermined speed;
• and
• a second setting unit that determines a target engine speed corresponding to the pump displacement detected by the detector and a target engine speed corresponding to the engine torque detected by the detector, and sets one of the determined target engine speeds as a target engine speed,
• wherein during drive control of the engine based on the second target engine speed, the second setting unit sets the target engine speed to be a higher one of (i) the target engine speed corresponding to the pump displacement detected by the detector, and (ii) the target engine speed corresponding to the engine torque detected by the detector, and the fuel injection device is controlled so that the engine is controllably driven at the target engine speed set by the second setting unit.