Hyundai Motor Group has developed the world’s first Continuously
Variable Valve Duration (CVVD) technology to feature in future Hyundai and Kia
vehicles. The innovation was revealed at Hyundai Motorstudio Goyang on
Wednesday, July 3, alongside the Smartstream G1.6 T-GDi the first engine to
feature the technology.
According to a release by Kia Pr Team , made available to OpenLife, CVVD
optimizes 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% boost in
performance and a 5% improvement in fuel efficiency. Furthermore, the
technology cuts emissions by 12%.
“The development of the CVVD technology is a good example how HMG is
strengthening our powertrain technology,” said Albert Biermann, President and
Head of Research and Development Division at Hyundai Motor Group. “We will
continue our innovation efforts to bring forth paradigm shifts and ensure
sustainability of our business model.”
Innovation: Continuously Variable Valve Duration
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.
Smartstream G1.6 T-GDi Engine
Unveiled alongside the new CVVD technology is the new Smartstream G1.6 T-GDi
Engine, a V4 gasoline turbo unit with 180 horsepower and 27.0kgm 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 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.
Additionally, 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% with the
application of low friction moving parts.
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