Fuel injection control apparatus

A fuel injection control apparatus for an internal combustion engine, the internal combustion engine including a piston reciprocating in a cylinder, a fuel injector arranged to inject a fuel into a combustion chamber facing the piston in the cylinder, a crank angle sensor detecting a crank angle including a first crank angle at which an intake stroke is started and a second crank angle at which a compression stroke is ended, and an intake air amount sensor detecting an amount of intake air into the cylinder, the apparatus comprising

• an electronic control unit having a microprocessor and a memory, wherein
• the microprocessor is configured to perform:
• determining an operation state of the internal combustion engine based on signals from the crank angle sensor and the intake air amount sensor;
• calculating injection target values including a target amount of injection, a target injection timing and a target injection frequency in a combustion cycle of the internal combustion engine within an injectable crank area other than a first prohibited area in which the crank angle is increased from the first crank angle by a predetermined increase angle and a second prohibited area in which the crank angle is decreased from the second crank angle by a predetermined decrease angle among an area from the first crank angle to the second crank angle, based on the operation state of the internal combustion engine;
• controlling the fuel injector so as to inject the fuel of the target amount of injection at the target injection timing in the injectable crank area;
• instructing a switching from a multiple fuel injection mode in which the fuel is injected into the combustion chamber in the injectable crank area a plurality of times to a fuel cut mode in which an injection of the fuel is stopped, and a switching from the fuel cut mode to the multiple fuel injection mode;
• determining whether it is possible to inject the fuel in accordance with the injection target values when the switching from the fuel cut mode to the multiple fuel injection mode is instructed, under a state that the target injection frequency included in the injection target values is the plurality of times;
• and
• modifying the injection target values by reducing the target injection frequency when it is determined that it is impossible to inject the fuel in accordance with the injection target values, and wherein
• the microprocessor is configured to perform
• the controlling including controlling the fuel injector, when the injection target values are modified, so as to inject the fuel in accordance with modified injection target values.