Engine downsizing involves decreasing engine displacement or the number of cylinder to raise fuel economy while maintaining or enhancing performance. Reducing engine displacement by 30% and 50% raises fuel economy by 15% and 25%, respectively, but it also results in lower engine power. Making up for this loss is the turbo charger, which powers the turbine with engine exhaust to suck in, compress and inject air into the engine. Engine downsizing is realized when the turbocharger meets direct injection (DI) technology, which enhances engines air absorption efficiency. Kia Motors has a full line up gasoline direct injection (GDI) models in all vehicle classes and Cerato Koup, Optima and Sportage feature T-GDI (turbo+GDI) technology (Optima and Sportage feature a turbo charger in American models). A car powered by the force of combustion generated when fuel and air meet. This is why there has been steadfast R&D on technologies to better control fuel and air boost performance and efficiency.
While GDI controls fuel, continuous variable valve lift (CVVL) deals with other half of the automotive power equation: air. The Nu CVVL engine developed by Kia Motors in 2012 controls air inflow by adjusting the intake valve based on speed or output to raise performance and fuel economy.
The Nu CVVL engine can be found in Optima (European and American models) and we are currently developing a next generation engine that boasts even greater fuel economy and performance.