Comments by "David Elliott" (@davidelliott5843) on "The World's First CVVD Engine - Genius!" video.

  1. How about the Fiat MultiAir which uses engine oil pressure to control the valves by hydraulic action.
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  2. The Fiat MultiAir uses a normal exhaust cam. The inlet is opened by hydraulics. The valve opening height, duration and even number of openings are fully controlled. They could do it with exhaust but presumably the benefits are less.
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  3. Fiat launched the MutiAir engine in 2009 predating this Hyundai by 10 years. Wikipedia says Multiair is a hydraulically-actuated variable valve timing and variable valve lift engine technology enabling "cylinder by cylinder, stroke by stroke" control of intake air directly via a gasoline engine's inlet valves. Developed by Fiat Powertrain Technologies Fiat could have used it on the exhaust side but found minimal benefits I
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