The ZR engine gasoline-engine-family, introduced in 2007 by Toyota Motor Corporation, uses a DOHC 16-valve cylinder head with a 4-cylinder die-cast block. Engines displace either 1.6-liters, 1.8-liters or 2.0-liters. Most engines in this family are equipped with Toyota's dual VVT-i technology that optimizes both intake and exhaust valve timing. This engine family is also the first to use Toyota's Valvematic system, first appearing on the Noah and Voxy in 2007 and then the European Avensis in 2009.