Engine speed control device

An engine speed control device for an engine, the engine speed control device at least comprising:

• an engine speed detecting means configured to detect an engine speed of the engine;
• a cooling water temperature detecting means configured to detect a temperature of a cooling water of the engine;
• a rack position detecting means configured to detect a rack position of a fuel injection pump;
• and
• a lubricating oil temperature detecting means configured to detect a lubricating oil temperature of the engine, wherein:
• the engine speed control device is configured to perform:
• a first PID gain calculation step of calculating a target engine speed to calculate a first PID gain based on an engine speed deviation between the target engine speed and an engine speed detected by the engine speed detecting means,
• a target rack position calculation step of correcting the first PID gain using a cooling water temperature correction factor based on a cooling water temperature detected by the cooling water temperature detecting means to thereby calculate a target rack position of the fuel injection pump,
• a second PID gain calculation step of calculating a second PID gain based on a rack position deviation between the target rack position and a rack position detected by the rack position detecting means, and
• a rack control signal producing step of correcting the second PID gain using a lubricating oil temperature correction factor based on a lubricating oil temperature detected by the lubricating oil temperature detecting means to thereby produce a rack control signal;
• the engine speed control device is further configured to control the engine speed by controlling the rack position based on the rack control signal;
• the cooling water temperature correction factor applied to correction of the first PID gain is prevented from being applied to correction of the second PID gain;
• and
• the lubricating oil temperature correction factor applied to correction of the second PID gain is prevented from being applied to correction of the first PID gain.