Knock control apparatus for internal combustion engine

A knock control apparatus for an internal combustion engine, comprising:

• a knock sensor that detects a vibration of the internal combustion engine;
• a knock determination portion that determines a presence or absence of an occurrence of a knock in the internal combustion engine on the basis of an output of the knock sensor;
• and
• a knock correction amount computation portion that computes, on the basis of intensity of a knock that occurs when the presence of an occurrence of a knock is determined by the knock determination portion, a knock correction amount by which a spark timing of the internal combustion engine is moved to a retard side and returns back the knock correction amount to an advance side when the absence of an occurrence of a knock is determined by the knock determination portion, wherein
• when a value of the knock correction amount on the retard side becomes equal to or exceeds a predetermined value, the knock correction amount computation portion limits and holds the knock correction amount at the predetermined value and returns back the limited knock correction amount to the advance side after a predetermined time calculated on the basis of the intensity of a knock that occurs.

A knock control apparatus for an internal combustion engine, comprising:

• a knock sensor that detects a vibration of the internal combustion engine;
• a knock determination portion that determines a presence or absence of an occurrence of a knock in the internal combustion engine on the basis of an output of the knock sensor;
• and
• a knock correction amount computation portion that computes, on the basis of intensity of a knock that occurs when the presence of an occurrence of a knock is determined by the knock determination portion, a knock correction amount by which a spark timing of the internal combustion engine is moved to a retard side and returns back the knock correction amount to an advance side when the absence of an occurrence of a knock is determined by the knock determination portion, wherein
• when a value of the knock correction amount on the retard side becomes equal to or exceeds a predetermined value, the knock correction amount computation portion limits and holds the knock correction amount at the predetermined value, and computes, as a virtual knock correction amount, a knock correction amount by which the spark timing is moved to the retard side when the knock correction amount is not limited to use one of the knock correction amount held at the predetermined value and the computed virtual knock correction amount, whichever has a smaller absolute value, as a knock correction amount by which the spark timing is moved to the retard side.