Hyundai Motor Group, Kia Motors‘ parent company, has developed the world’s first Continuously Variable Valve Duration (CVVD) technology to feature in future Kia vehicles.
The innovation was revealed at Hyundai Motorstudio Goyang alongside the Smartstream G1.6 T-GDi, the first engine to feature the technology.
CVVD is claimed to optimise 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 4 per cent boost in performance and a 5 per cent improvement in fuel efficiency. In addition, the technology cuts emissions by 12 per cent.
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 maximise 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, an I4 gasoline turbo unit with 180 horsepower and 27.0kgm of torque.
The new powertrain is the first to utilise the Group’s new CVVD technology and also features Low-Pressure Exhaust Gas Recirculation (LP EGR) to further optimise 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 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 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.