Hyundai unveils CVVD engine technology

Hyundai Motor Group has developed the world’s first Continuously Variable Valve Duration (CVVD) technology to feature in future Hyundai and Kia vehicles.

CVVD optimises both engine performance and fuel efficiency while also being eco-friendly. The valve control technology regulates the duration of valve opening and closing according to driving conditions, achieving a four per cent boost in performance and a five per cent improvement in fuel efficiency. Furthermore, the technology cuts emissions by 12%.

Until now, an internal combustion engine’s performance and efficiency have been governed by variable valve control technology that adjusts the timing of valve opening and closing and depth of the valve’s opening, with engine power 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. CVVD takes the technology in a new direction by adjusting how long a valve is open.

When the vehicle is maintaining a constant speed and requires low engine output, CVVD opens the intake valve from the middle to end of the compression stroke. This helps 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.

Unveiled alongside the new CVVD technology is the new Smartstream G1.6 T-GDi Engine, a V4 gasoline turbo unit with 180 horsepower and 265Nm of torque. The 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 optimise fuel efficiency.