Hyundai announces "world's first" Continuously Variable Valve Duration engines
Set to debut in a new 1.6-liter 4-cylinder Smartstream turbo engine, Hyundai's new valve tech is able to continuously change the duration of valve openings to suit driving conditions, which Hyundai says results in a 4 percent performance boost, 5 percent better fuel economy and 12 percent lower emissions.
Hyundai calls it the "world's first continuously variable valve duration (CVVD) technology," and says it differs from garden-variety variable valve timing systems because their valve closing timing is dependent on their opening timing. Instead, this system adjusts the length of time the valve is open, staying open longer at lower RPM and lower engine loads to improve efficiency by reducing compression resistance.
At higher RPMs and engine loads, the valves close quicker, at the beginning of the compression stroke, to maximize the amount of air in the cylinder when the spark ignites it and deliver extra torque and performance as a result.
The system appears only to operate on the intake valves, and calling it the "world's first" should raise the ire of companies like Camcon Automotive and Koeniggsegg's FreeValve, which use digitally-controlled valve actuation systems to precisely control not only the opening and closing times of each valve, but how much lift it's got as well – thus giving you full control over the valve duration and a bunch of other things besides.
Instead of this level of full control, the Hyundai Motor Group's solution appears to move the camshaft slightly off center to control the length of time the valve's open for, and this appears to affect both opening and closing timing, with the maximally open point staying at the same spot in the combustion cycle.
Hyundai and Kia will begin rolling the tech out on new cars soon, and has unveiled the first engine to feature CVVD tech, the Smartstream G1.6 T-GDi engine. It's a four-cylinder 1.6-liter turbo making 180 hp and 265 Nm (195 lb-ft) of torque. In addition to the valve tech, it'll also run low-pressure exhaust gas recirculation to help cool the combustion chambers and reduce nitrogen oxide emissions, and a thermal management system designed to quickly heat or cool the engine into its optimal temperature range.
We'll first see the Smartstream engine in the upcoming Hyundai Sonata Turbo, due to appear later in 2019. Check out a video of the valve tech below, which isn't massively informative, but is certainly very stylish, even if it does seem to imply that the engine lives in one of the wheel hubs.
Source: Hyundai Group