Variable valve timing, or VVT, has been around since at least the 1960s. Essentially, this is a name given to a very wide range of techniques used to provide greater power from the engine at higher speeds or when the engine is under a load.
Different automakers have different variable valve timing systems, bust almost all of them rely on a variable valve timing solenoid to control the flow of oil to the VVT system when it engages (VVT isn’t used at idle, and really only comes into play at higher speeds/load needs). When the solenoid activates, oil is sent from the system to lubricate the VVT chain and gear). However, if the solenoid is failing or blocked, the system will not work and it needs to be replaced.
[ Ссылка ]
