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Old 07-29-2019, 02:07 AM   #11 (permalink)
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Old news, that video is from 2016. They definitely haven't gotten this to work. I would imagine high power consumption is the main problem.

Multiair is the best system on the market right now. It's basically fully hydraulic valves. The problem is...no other manufacturer has dared to use this. You would think that with the complexity of a hydraulic valve lash adjuster and cylinder deactivation mechanism that someone would've thought putting full hydraulic control would be easier.

If you look at the best new engines (Toyota Dynamic Force and Mazda Skyactiv-X), you'll notice they have very primitive cam phasing VVT, and use high volume cooled EGR to cut pumping losses down. Fancier fuel injection systems allow good fuel-air mixing without the need for different cam profiles. If you want to spend more money, Honda shows us it's not very hard to tack on a second cam profile to squeeze out a little bit more.

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Old 07-29-2019, 07:56 AM   #12 (permalink)
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I would also make the assumption that high engine speed would be a challenge.
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Old 07-29-2019, 01:39 PM   #13 (permalink)
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Its probably not reliable or cost effective. I mean they have been using pneumatic valve springs since the 1980s in racing, but Koenigsegg is still using a new casting Ford small block modular engine.
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Old 08-04-2019, 06:56 PM   #14 (permalink)
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Quote:
Originally Posted by Ecky View Post
I understand a roller rocker valve system has relatively low parasitic losses, actuating the valves returns most of the energy back to the camshaft as the lob passes and the spring pushes back up. This system would use energy to actuate the valves in both directions.
But it does get valve springs for return. The hydraulic is there more for dampening, and the variable amount of oil does limit the valve lift.
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Old 03-03-2020, 08:04 PM   #15 (permalink)
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Koenigsegg finally released info about the first car to be fitted with the Freevalve setup, the Gemera.

https://www.freevalve.com/events/koe...eva-unveiling/
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Old 03-04-2020, 08:46 AM   #16 (permalink)
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2.0L 3 Cylinder. Thats wild. Did they ever start it to hear it?
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Old 03-05-2020, 07:31 PM   #17 (permalink)
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Okay I made a thread in General Efficiency Discussion after seeing the Engineering Explained video of Hyundai CVVD pop up, but I feel like there's basically no advantage to Koenigsegg Freevalve over that. If you have control over duration, you have full control over overlap, scavenging, and volumetric efficiency.

The only thing it can't do is use extremely low lift to produce charge motion, but if you care about that you can also just use lost motion EVIC variable lift like Multiair or Valvetronic, add tumble generator valves, or use multi-point/laser/microwave/jet/SPCCI ignition.

Continuously variable duration adds no reciprocating inertia, and only a small amount of sliding friction when the valve duration is changed (mostly when it's being shortened, aka high load low rpm which is not a common operating condition). You could even run motorcycle engine speeds no problem.

EDIT: Wait a minute, I just watched one of the videos...Christian said it can run as a TWO STROKE sometimes :O Okay that's actually maybe worth the expense and power consumption. Since it's turbocharged, when there's enough boost to scavenge the cylinder it would produce some pretty ridiculous torque.

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Old 03-06-2020, 02:52 PM   #18 (permalink)
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Wait a minute, I just watched one of the videos...Christian said it can run as a TWO STROKE sometimes :O Okay that's actually maybe worth the expense and power consumption. Since it's turbocharged, when there's enough boost to scavenge the cylinder it would produce some pretty ridiculous torque.
Makes me wonder how the Freevalve system could work in an engine similar to the old-school Detroit Diesel ones. Or eventually with a twincharger setup in a regular gasser like Volvo uses into its T6 and T8 models.

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