Variable timing system (VVT) valve opening and closing system in in-burner engines is variable and proportional to engine conditions. Variable timing system is a process of changing the time of departure and valves and more for better efficiency and efficiency.fuel savings and optimal exit of smoke. Further, this system, along with system variable amount of opening of the valve (the length or size of the valve comes out), or variable Valve Lift, the acronym VVL to be handled. There are many ways to achieve the performance of these systems, including mechanical devices-up to electro-hydraulics and systems without valves. It is also said that strict regulations have been published by the Association of mechanical engineers to require manufacturers of vehicles and motor vehicles to use the system.