Internal combustion engine control

A method of controlling an internal combustion engine for a vehicle, the method comprising:

• providing an internal combustion engine having an exhaust camshaft phaser and a flat-response knock sensor;
• starting the internal combustion engine;
• receiving a first knock sensor signal from the knock sensor;
• determining a first octane rating (OR) based on the first knock sensor signal and an algorithm;
• communicating a camshaft timing change to the exhaust camshaft phaser if the first octane rating (OR) is less than 100%;
• maintaining a current camshaft timing if the first octane rating (OR) is 100%;
• receiving a second knock sensor signal from the knock sensor;
• determining a second octane rating (OR) based on the second knock sensor signal and the algorithm;
• communicating a camshaft timing change to the exhaust camshaft phaser if the second octane rating (OR) is less than 100%, and
• maintaining a current camshaft timing if the second octane rating (OR) is 100%.