Variable valve lift (VVL) is an automotive piston engine technology which varies the height a valve opens in order to improve performance, fuel economy or emissions. There are two main types of VVL: discrete, which employs fixed valve lift amounts, and continuous, which is able to vary the amount of lift. Continuous valve lift systems typically allow for the elimination of the throttle valve.[citation needed]
When used in conjunction with variable valve timing (VVT), variable valve lift can potentially offer infinite control over the intake and exhaust valve timing.[citation needed]