What is the ignition timing?

At the end of the compression stroke of the engine, when the piston reaches the peak of the stroke, the ignition system provides high-voltage spark to the spark plug to ignite the compressed mixture in the cylinder to do work. This time is the ignition timing. In order to maximize the ignition energy, the ignition timing is generally advanced by a certain amount, so it is ignited at the moment when the piston is about to reach the top dead center, not just when it reaches the top dead center. This advance is called the ignition advance angle.