The camshaft is a shaft that uses projections (cams) to open and close the valves that let the air/fuel mixture into the engine and let the exhaust escape. As the camshaft rotates, it operates the valves at the right time and in the right order to control the charge cycle.
Camshaft adjustment varies the opening times of the valves to suit all operating conditions. This ensures ideal charge cycles within a wide range of engine speeds and loads. Fuel consumption and pollutant emissions are reduced, while torque and smoothness are increased.
During continuous camshaft adjustment, the timing of all the valves, driven by the respective camshaft, can be shifted in the same direction. This means that in engines with a double overhead camshaft, it is possible to influence the size and positioning of the valve opening overlap, thus enhancing the characteristics of full-load and part-load operation.