Fuel injection control device and fuel injection control method

A fuel injection control method for controlling a fuel injection valve of an internal combustion engine, the method comprising:

• (a) a step of counting a number of injection pulses of the fuel injection valve;
• (b) a step of estimating a deterioration state of the fuel injection valve on the basis of the number of injection pulses counted in the step (a);
• and
• (c) a step of correcting the injection amount of the fuel injection valve on the basis of the deterioration state of the fuel injection valve estimated in the step (b),
• wherein in a case where a total number of injection pulses over multiple cycles of the engine counted in step (a) exceeds a predetermined threshold value,
• determining that the fuel injection valve is deteriorated, and
• correcting an injection pulse width and a driving current waveform of the fuel injection valve in accordance with the deterioration state.

A fuel injection control device controlling a fuel injection valve of an internal combustion engine, the device comprising:

• one or more processors and one or more non-transitory computer-readable storage media, the non-transitory computer-readable storage media having stored thereon at least:
• a deterioration determination unit that determines a deterioration state of the fuel injection valve;
• an injection amount learning unit that learns an injection amount of the fuel injection valve;
• and
• a learning frequency change unit that changes a learning frequency of the injection amount learning unit in accordance with the deterioration state of the fuel injection valve,
• wherein in a first case where a first number of injection pulses over multiple cycles of the engine falls within a first predetermined range, the deterioration determination unit determines that the fuel injection valve is not deteriorated, and the learning frequency change unit decreases the learning frequency of the injection amount learning unit;
• and
• in a case where a second number of injection pulses over multiple cycles of the engine exceeds a second predetermined threshold value, the deterioration determination unit determines that the fuel injection valve is deteriorated, and the learning frequency change unit increases the learning frequency of the injection amount learning unit.