Let's be honest, the principle of changing over from a shallow- to a steep cam-throw with the respective valve-timing, is already well known to us. Indeed the effort was never before as low as it is here. Only one actuator in the middle, shifts a camshaft which is hollow-drilled and, for whatever reason, is made up of two parts.
We are of course, talking about the inlet-camshaft, with which one always starts when it's a matter of adapting the engine control to various working conditions while the engine is running. Have a look at the keyways in the middle and the finely worked cam-throws together with the rollers of the cam followers, you should be able to fathom the mechanism quite easily. Further explanations can be found in the video below.
The remarks from the manufacturers, concerning this process, are something quite new. One would like to know more about the differences in the four phases of the controlling:
1. Very low torque through the throttle flap and the shallow cam-throws. 2. Slightly increased torque through the shifting of the valve timing. 3. Higher demands through the increased use of the turbocharger. 4. Maximum torque through switching over to the large cam-throws.
Just give this a moment's thought: Should the driver require a bit more torque in the lower load-range, it's quite possible, that it's not the throttle-flap that is opened, but the intake camshaft that is shifted. Or in the higher load-range, when accelerating, the charging pressure is either increased or reduced with the simultaneous change-over to a steeper cam-throw.
These are all efforts, to avoid too much reduction of the air intake path. In addition, there are a certain amount of fireworks around the spark plugs through multiple ignition, and in the direct injection through more partial injecting, to ensure that during a weak transfer rate, the swirling is kept fairly constant. One can well imagine, the engine management has a lot of work to do. 05/15