Controller for internal combustion engine

A controller for an internal combustion engine that controls the internal combustion engine which is provided with a detected unit which has a plurality of teeth at a preliminarily set unit angle interval with a chipped tooth section and rotates integrally with a crankshaft, and a crank angle sensor which detects a tooth among the plurality of teeth, the controller for the internal combustion engine, comprising at least one processor configured to:

• detect a period when the tooth passes, based on an output signal of the crank angle sensor, determine a period corresponding to the chipped tooth section, and determine a crank angle corresponding to the passed tooth;
• where virtual unit angle intervals refer to intervals between chipped teeth that are assumed to be provided in the chipped tooth section, among the plurality of teeth, and corresponds to a value greater than a number of the chipped teeth by 1;
• wherein the at least one processor is further configured to:
• calculate an average period of the virtual unit angle intervals in the chipped tooth section, by dividing the period of the chipped tooth section by a value obtained by adding 1 to the number of the chipped teeth;
• make the average period of the virtual unit angle intervals correspond to a central angle of the chipped tooth section;
• estimate a period of each of the virtual unit angle intervals in the chipped tooth section based on the period corresponding to the chipped tooth section, a period before the chipped tooth section, and a period after the chipped tooth section, by an approximate line which passes the period before the chipped tooth section, the average period of the virtual unit angle intervals at the central angle of the chipped tooth section, and the period after the chipped tooth section;
• and
• control one or both of an ignition timing and an EGR amount of the internal combustion engine based on the estimated period of each of the virtual unit angle intervals.