10.4.6 Ignition timing regulators
In order for the fuel-air mixture to burn while the piston moves from the top dead center to the bottom, it must be ignited a little earlier. Ignition advance angle is the main indicator of the ignition moment. It indicates how many degrees before TDC on the compression stroke there will be a breakdown between the electrodes of the spark plug.
The change of the ignition advance angle is carried out mechanically - by turning the contacts relative to the drive shaft in one direction or another in distributors of the type described above.
2 MB