Variable Valve Timing Systems

In conventional internal combustion engines intake valve advance and retard have been adjusted ideally only for one revolution of the engine, and maximum engine performance is obtained at only one revolution. In order to achieve high engine performance at different revolutions, variable valve timing systems are needed to change valve opening advance and retard depending on the engine revolution and driving conditions. These additional systems increase consumed energy in the engine as they enhance the engine performance. Therefore, additional power acquired from variable valve timing systems should be over than the power consumed by the system. In this chapter, Variable Valve Timing Systems, application of three-graded pneumatic-driven Variable Valve Lifting System on a conventional engine and its effect on the engine performance was represented.