Hyundai Motor Group unveiled the world’s first CVVD (Continuously Variable Valve Duration) technology for future Kia and Honda cars at Hyundai Motorstudio Goyang. The Smartstream G1.6 T-GDi was also unveiled at this event and it would be the first engine that would use the CVVD technology.
Previous technologies like CVVT (Continuously Variable Valve Timing) and CVVL (Continuously Variable Valve Lift) would not be able to control valve duration and would not be able to modulate the air intake to suit diverse driving scenarios effectively. CVVD bridges that gap as it can regulate how long the valve is open.
Albert Biermann, president and head of research and development division at Hyundai Motor Group said: “The development of the CVVD technology is a good example how Hyundai Motor Group is strengthening our powertrain technology.”
Hyundai claims that CVVD technology will improve engine performance and fuel efficiency by four percent and five percent respectively and that the emissions also go down by 12 percent.
Earlier, the valve’s opening timing and closing timing could be adjusted from the camshaft, but what could not be adjusted was the duration of the opening and closing. The closing timing was always a function of the opening timing. However, this new technology allows the vales to open for a shorter or longer duration during each ignition cycle.
When the car is at a constant speed and does not need high power output from the engine, CVVD keeps the intake valve open at the start of the compression stroke, only shutting it when half the stroke is completed. This reduces resistance during compression and thus, increases efficiency. However, if the car is going at higher speeds and a higher engine output is required, the CVVD closes the intake valve at the beginning of the compression stroke to maximise the amount of air used in the combustion process which in turn increases the torque and leads to better acceleration.
The Smartstream G1.6 T-GDi engine will be the first engine to use CVVD technology. The engine will be running a turbo-petrol with a V4 cylinder configuration that will put out 180bhp and 265Nm of torque. Other features of the Smartstream G1.6 T-GDi include an exhaust gas recirculation system which returns some of the gas burnt back to the combustion chamber. Doing so creates a cooling effect that reduces the emission of nitrogen oxides. It also has a low pressure system that redirects burnt emission gas to the front of the turbocharger compressor instead if the intake system, to increase efficiency under high load conditions.
The friction in the engine is reduced by 34 percent courtesy use of low friction parts. The engine comes with a thermal management system that heats or cools the engine to an ideal temperature along with a direct spray system that can achieve 350bar of pressure over the 250bar that the previous T-GDi engine could do.
The engine will be seen on the Hyundai Sonata Turbo which will make its international debut in the second half of the year. The engine configuration for Kia cars will be revealed at a later time.
Watch how the technology works:
Words by Karan Ramgopal