Control apparatus of internal combustion engine

A control apparatus of an internal combustion engine, comprising:

• a knock sensor that detects a vibration of the internal combustion engine and generates an output containing a signal corresponding to the detected vibration;
• a crank angle sensor that detects a crank angle of the internal combustion engine and outputs a signal corresponding to the detected crank angle;
• a vibration waveform calculation unit that calculates a vibration waveform of a knock-specific frequency component of the internal combustion engine over a plurality of ignition cycles of the internal combustion engine according to an output of the knock sensor and an output of the crank angle sensor;
• a vibration waveform standard deviation calculation unit that calculates a standard deviation of the calculated vibration waveform over the plurality of ignition cycles;
• a vibration position detection unit that detects, as a vibration position by combustion of the internal combustion engine, a position corresponding to the crank angle at which the calculated standard deviation of the vibration waveform exceeds a predetermined first determination level;
• an actual ignition timing calculation unit that calculates an actual ignition timing of the internal combustion engine according to the detected vibration position;
• and
• an ignition timing adjustment unit that is capable of adjusting an ignition timing of the internal combustion engine according to the calculated actual ignition timing.