How does VVTi work?
 

I've searched the internet and can't find an answer on how the VVTi in our cars work.

The most I get is a general overview such as at xxxx RPM, one or the other cam is retarded/advanced and you get more torque/power...

I'd like to know how the cam is advanced/retarded. Oil pressure? Through what orifice(s)? Opened electronically? Or mechanically with springs or weights (probably not)? Magnetically, like the a/c clutch?

It sucks that the dealer doesn't sell service manuals, which is where I would normally look for this kind of information.

TIA

Google it.

https://web.archive.org/web/20110820...hatsInside.htm

Interesting question. I found the answer in the link kindly provided by Tcoat.

(l) Variable valve timing control

(1) A rotor-based design with high efficiency and low friction while driving has been adopted.

(2) Double-tooth rotors have been adopted on both the intake and exhaust sides. When stopped, the rotor on the intake side is fixed in the intermediate locking position, and the rotor on the exhaust side is fixed in the maximum advance position, using lock pins.

(3) The variable valve timing control oil control solenoid attached to the timing chain or belt cover sub-assembly activates the spool valve, hydraulic pressure to the advance chamber and retard chamber inside the cam sprocket is regulated, and the phases of the intake and exhaust cam shafts are continuously changed, according to signals from each sensor to the ECM.

The link actually comes to you courtesy of @Ultramaroon It is his sig.