CVVD technology: what is it and how does it work?

Hyundai has developed a new technology called CVVD that will be included in the new Kia and Hyundai models. The first engine to feature it will be the Smartstream G1.6 T-GDi.

What is CVVD technology and how does it work? This new system, developed by the Hyundai Group, will be used in new Hyundai and Kia models. This innovation was presented at the Hyundai Motorstudio Goyand on July 3. Accompanying this innovation is the first engine with this system, called Smartstream G1.6 T-GDi.

CVVD technology “optimizes both engine performance and fuel efficiency, while being environmentally friendly. This valve control system regulates the duration of the valve opening and closing depending on driving conditions, achieving a 4% increase in performance and a 5% improvement in fuel efficiency. In addition, the technology reduces emissions by 12%”.

Albert Biermann, President and Head of Research and Development of the Hyundai Group, has stated that “the development of CVVD technology is a good example of how the Hyundai Group is strengthening propulsion system technologies.” “We will continue our innovation efforts to produce changes and ensure the sustainability of our business model.”

https://www.youtube.com/watch?v=5atYksEpAm8

CVVD technology: what do these initials mean?

Until now, the performance of an internal combustion engine has been governed by control systems that adjust both the valve opening and closing timing and the valve lift depth, based on the intake, compression, expansion and exhaust cycles of the engine.

These systems control the valve opening and closing timing, as is the case with CVVD, Continuously Variable Valve Timing, or CVVL, Continuously Variable Valve Lift. It is important to note that neither technology fully controlled the valve opening timing, as the timing did not depend on the various driving situations that may arise. The new system takes this technology in a new direction.

“When the vehicle maintains a constant speed and requires low engine power, CVVD opens the intake valve from the middle to the end of the compression stroke. This helps improve fuel efficiency by reducing the resistance caused by compression. On the other hand, when engine power is high, for example at high speed, the intake valve closes at the beginning of the compression stroke to maximize the amount of air used for combustion, increasing torque to improve acceleration.”

Smartstream G1.6 T-GDi engine

Together with the new CVVD technology, the new Smartstream G1.6 T-GDi engine is presented, a turbocharged petrol unit with 4 cylinders in line, 180 CV and 27.0 kgm of torque. This engine is the first to use the new CVVD technology and also features low-pressure exhaust gas recirculation (LP EGR) to further optimize fuel efficiency.

The exhaust gas recirculation system returns part of the gas burned by the engine to the combustion chamber, producing a cooling effect and reducing nitrogen oxide emissions. The G1.6 T-GDi also has a low-pressure system that redirects the burned exhaust gas to the front of the turbocharger compressor, instead of the intake system, to increase efficiency under high-load conditions.

In addition, it features an Integrated Thermal Management System that quickly heats or cools the engine to an optimal temperature, and a powerful direct injection system reaching 350 bar, surpassing the 250 bar of the previous T-GDi engine. Furthermore, engine friction is reduced by 34% through the use of low-friction moving parts.