Automotive designers have been working on the idea of engines without camshafts for many years. Camshafts add complexity, weight and friction to engines. Due to it's physical profile, a cam can only control the movement of a valve within limited parameters, that won't be optimal for all operating conditions. Advancements in variable valve timing technology, in recent years have improved performance and efficiency. However, these VVT systems add still more mechanical complexity and weight.
While most consumers are now carefully looking at the fuel economy of their next car, legislators are still focusing their efforts on reducing vehicle emissions. While emission standards vary around the world, it is becoming increasingly difficult to meet the existing and future standards with incremental changes to conventional gasoline and diesel engines. Full hybrids, like the Toyota Prius and Ford Escape, offer fuel economy improvements, and as a direct result, produce lower CO2 emissions. B