Hyundai unveils Continuously Variable Valve Duration (CVVD) technology

- Continuously Variable Valve Duration (CVVD) technology unveiled

- Technology claims to increase performance by 4 per cent, fuel efficiency by 5 per cent and decreases emissions by 12 per cent

- New engine technology to debut in Smartstream G1.6 T-GDi engine

- Hyundai Sonata Turbo to get Smartstream G1.6 T-GDi engine  

Future Hyundai and Kia vehicles will get the Continuously Variable Valve Duration (CVVD) technology. The Hyundai Motor Group has developed the world’s-first engine technology that controls the timing of valve opening and closing as per the driving conditions. The new engine technology will debut in the Smartstream G1.6 T-GDi engine in the Hyundai Sonata Turbo, which is set for introduction in the second half of this year. 

Hyundai claims that the CVVD optimizes both engine performance and fuel efficiency while also being eco-friendly. The new technology claims that regulating the valve opening and closing as per driving conditions has helped in achieving a four per cent boost in performance and a five per cent improvement in fuel efficiency. Additionally, the technology claims to have reduced emissions by 12 per cent.

The new Smartstream G1.6 T-GDi engine, a V4 gasoline turbo unit generates 180bhp and 265Nm of torque. This new powertrain is the first to utilize the Group’s new CVVD technology and also features Low-Pressure Exhaust Gas Recirculation (LP EGR) to further optimize fuel efficiency. The exhaust gas recirculation system returns some of the gas burnt by the engine to the combustion chamber, producing a cooling effect and reducing the emission of nitrogen oxides. The G1.6 T-GDi also features a low-pressure system that redirects the burnt emission gas to the front of the turbocharger compressor, rather than the intake system, to increase efficiency under the high load condition. 

The new unit also has an Integrated Thermal Management System that quickly heats or cools the engine to an optimal temperature, and a strong direct spray system that achieves 350bar, surpassing the 250bar of the previous T-GDi engine. In addition, engine friction is reduced by 34 per cent with the application of low friction moving parts.

The existing engines are based on the variable valve control technology that adjusts the timing of valve opening and closing and depth of the valve’s opening and the engine power is produced through the fuel intake-compression-expansion-exhaustion cycle. Typical variable valve control technologies manage the timing of the valve’s opening and closing (as in Continuously Variable Valve Timing - CVVT) or control the volume of air admitted by adjusting the depth of the opening (Continuously Variable Valve Lift - CVVL). Previous variable valve control technologies could not regulate valve duration, as the valve’s closing timing was subordinate to opening timing and could not respond to diverse driving situations. The CVVD takes the technology in a new direction by adjusting how long a valve is open.

When the vehicle is at a constant speed and it requires a low engine output, the CVVD opens the intake valve from the middle to end of the compression stroke to improve fuel efficiency by reducing the resistance caused by compression. On the other hand, when engine output is high, such as when the car is driving at a high speed, the intake valve is closed at the beginning of the compression stroke to maximize the amount of air used for the explosion, enhancing torque to improve acceleration.