How does oil control valve actuate VVT ?

I was reading from various sources about Variable Valve Timing. What I've gathered so far is that the ECU collects input from various sensors and then (as I understand, correct me if wrong) sends off a signal to the oil control valve, AKA camshaft solenoid, which actuates the VVT. My question is what is the mechanism behind how this valve actually controls the timing of valve openings and the opening "aperture", which seems to be the essence of VVT.

As a bonus question, can you explain what are all the sensors used to gather the input based on which the ECU determines whether to engage the oil control valve?

If any of my assumptions are wrong, please correct me.

 

"Mechanism"
It's a hydraulic operated variable cam gear controlled by the oil control valve, which is controlled by the ECU, which in order for it to give the "go ahead" needs to meet certain logic (yes/no) requirements.

The cam gear advances and retards the intake cam thereby adjusting the valves open and close timing, however since it's not an entirely different lobe profile like the Honda system, it cannot control lift or duration.

 

Pulled from another site, "Toyota's VVTL-i system is far less complicated and only requires water temperature, crankshaft position sensor and engine rpm before the lift mechanism is activated."

 

this is an AWESOME video !! i first thought the guy was faking an accent for fun...