Engine control device and engine control method

An engine control device of an engine including an idle speed control (ISC) device provided for an intake bypass passage connecting an upper side and a lower side of a throttle valve installed in an intake passage so as to control an idle speed of the engine by adjusting an amount of air flowing through the intake bypass passage at a time of idling of the engine, the engine control device comprising:

• a throttle opening degree sensor disposed in the intake passage and configured to detect a degree of opening of the throttle valve;
• an intake pressure sensor disposed in the intake passage and configured to detect an intake negative pressure at the lower side of the throttle valve;
• and
• a control unit configured to control an output of the engine,
• wherein the control unit is configured to perform engine output suppression control by suppressing the output of the engine after determining that an ISC valve of the ISC device is abnormal based on the degree of opening of the throttle valve detected by the throttle opening degree sensor being within a predetermined range, the intake negative pressure detected by the intake pressure sensor being lower than a threshold value, detection of an increase in engine speed that is more than a first predetermined amount within a predetermined time during a first engine speed increase determination step, and detection of an increase in engine speed that is more than a second predetermined amount within a second predetermined time, wherein the second predetermined time is longer than the first predetermined time.