Variable Valve Timing with intelligence (VVT-i) This system selects the ideal intake and exhaust valve overlap under all engine operating conditions. VVT-i virtually eliminates the traditional compromises between low-end torque and high-rpm horsepower. It also helps enhance fuel economy and reduces emissions so effectively that it eliminates the need for the exhaust gas recirculation (EGR) emissions device.
http://www.toyota.com/help/glossary.html#v
