Like Mazda’s SkyActiv X, the CVVD engine could change internal combustion forever.
Unlike Mazda signaled with its SkyActiv X engine, Hyundai and Kia are no strangers to electrification, a point that’s been driven home by great electric cars like the Niro and Kona EV. Still, the two partnered Korean automakers have not ditched the internal combustion engine entirely in order to focus more attention on electrified models. Instead, they have turned their efforts towards engineering a better engine that saves fuel and more importantly, keeps their gasoline-powered cars within future regulatory limits.
And now the two automakers are ready to show us the fruits of their labor, the world’s first Continuously Variable Valve Duration, or CVVD engine. As its name implies, the CVVD engine attempts to optimize performance and fuel efficiency by regulating the duration of valve opening and closing according to driving conditions.
It may seem like a minor change, but the clever optimization trick helps the engine increase its performance by 4%, improve fuel efficiency by 5%, and decrease emissions by 12% all in one go. The difference between Hyundai and Kia’s CVVD system is that rather than vary when the valves open and close like a standard variable valve timing system does, it changes up how long the valves remain open or closed.
At low speeds, the engine mimics an Atkinson-cycle engine by holding the intake valve open from the middle to the end of the compression stroke to reduce the amount of fuel economy-killing resistance it encounters, whereas it closes the intake valve at the beginning of the compression stroke like an Otto-cycle engine under load to maximize the amount of air used for the explosion and increase torque output.
"The development of the CVVD technology is a good example of how Hyundai Motor Group is strengthening our powertrain technology,” said Albert Biermann, President and Head of Research and Development Division at Hyundai Motor Group. "We will continue our innovation efforts to bring forth paradigm shifts and ensure sustainability of our business model.”
The first engine to receive the technology will be Hyundai’s new Smartstream G1.6 T-GDi Engine, a V4 gasoline turbo motor that makes 180 horsepower and 195 lb-ft of torque and will debut on the Hyundai Sonata Turbo during the second half of 2019.