Engine controller and engine control method

An engine control method comprising:

• calculating a first intake air amount, which serves as a calculated value of an intake air amount of an engine, based on a detected value of an intake air flow rate of an air flowmeter;
• calculating a second intake air amount, which serves as a calculated value of an intake air amount of the engine, based on any one of a detected value of an intake pipe pressure and a throttle opening degree instead of the detected value of the intake air flow rate;
• determining whether intake pulsation in an intake passage of the engine is large by determining whether the pulsation is greater than or equal to a preset determination value;
• in the determining, when determining that the intake pulsation is not large, calculating a difference amount of the second intake air amount from the first intake air amount;
• setting the first intake air amount as an intake air amount calculated value of the engine when determining, in the determining, that the intake pulsation is not large, and setting a corrected second intake air amount, which is a sum of the second intake air amount and the difference amount, as the intake air amount calculated value when determining, in the determining, that the intake pulsation is large;
• performing a fuel injection control on an injector by determining a fuel injection amount based on the set intake air amount calculated value;
• and
• learning of, in the difference amount calculation process, a difference amount learning value, which is a learning value of the difference amount, for each of difference amount learning regions divided from one another in accordance with a rotation speed of the engine.

A non-transitory computer-readable storage medium that stores a program causing a processor to execute an engine control process, the engine control process comprising:

• a first intake air amount calculation process for calculating a first intake air amount, which serves as a calculated value of an intake air amount of an engine, based on a detected value of an intake air flow rate of an air flowmeter;
• a second intake air amount calculation process for calculating a second intake air amount, which serves as a calculated value of an intake air amount of the engine, based on any one of a detected value of an intake pipe pressure and a throttle opening degree instead of the detected value of the intake air flow rate;
• a determination process for determining whether intake pulsation in an intake passage of the engine is large by determining whether the pulsation is greater than or equal to a preset determination value;
• a difference amount calculation process for, when determining in the determination process that the intake pulsation is not large, calculating a difference amount of the second intake air amount from the first intake air amount;
• a calculation mode switching process for
• setting the first intake air amount as an intake air amount calculated value of the engine when determining in the determination process that the intake pulsation is not large, and
• setting a corrected second intake air amount, which is a sum of the second intake air amount and the difference amount, as the intake air amount calculated value when determining in the determination process that the intake pulsation is large;
• an injector driving process for performing a fuel injection control on an injector by determining a fuel injection amount based on the set intake air amount calculated value;
• and
• learning of, in the difference amount calculation process, a difference amount learning value, which is a learning value of the difference amount, for each of difference amount learning regions divided from one another in accordance with a rotation speed of the engine.