FreeValve Isn't a Big Deal. Here's why
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2023-05-07に共有
In November 2016, Chinese automobile manufacturer Qoros Auto displayed the Qoros 3 hatchback at the 2016 Guangzhou Motor Show. This car featured a camless “Qamfreee” engine using freevalve technology. The Qoros3 never left the concept stage and never became a mass production reality.
In 2020 The Koenigsegg Gemera was unveiled. It featured a 2.0 liter inline three cylinder engine with freevalve that makes 600 horsepower. Production of the Gemera was supposed to begin in 2021. The date has since been moved to 2024.
So it has been 8 years since the announcement of Freevalve but it seems that today in 2023 we are no closer to this technology being reality than we were back in 2015. Why is that? Well, that’s exactly what I will attempt to answer in this video and more importantly I will also explain why freevalve isn’t as big of a deal as it initially seems and why it’s possible that this technology will never become mainstream mass production reality.
Don’t get me wrong. Freevalve is incredibly cool and I would love to see it become reality and I would love to own a vehicle with freevalve, but unfortunately the common sense realist inside me is skeptical and to explain the reasons behind my skepticism we first have to understand why freevalve is touted as a revolutionary technology that can dramatically improve engines.
As you probably know valves let fresh air in and exhaust out of the engine. And the camshaft is the physical metal “programing” of those valves. The camshaft determines when, how much and how long the valves open. The problem with a traditional fixed valve timing is that our “programing” always stay the same. Once the camshaft is ground everything is 100% fixed throughout the entire rpm range of the engine.
So let’s imagine that we have to choose a camshaft for an engine and let’s imagine that we want to extract maximum performance from our engine. So we choose a camshaft with very high lift and very high duration. This let’s in a lot of air into the engine we then add lots of fuel and produce powerful and fast combustion and make big power. But we pay a very high price for this. At low rpm our vehicle feels sluggish and unresponsive and our idle is unstable and produces high emissions.
The reason behind this is that low rpm means low piston speeds. And low piston speeds means low air velocity. Low air velocity means poor air and fuel mixing. Poor air and fuel mixing means poor combustion. Poor combustion means reduced torque.
Now the key thing here is that air velocity and air quantity sort of work against each other. If you have a large opening or cross-section you can have high air flow quantity but the larger your cross section the lower your air velocity. So at low rpm what we actually want to do is open the valve less in order to reduce our cross-section and increase air velocity in order to improve air fuel mixing and restore some low torque rpm. But of course if we reduce lift we reduce our maximum potential performance. For now we will ignore the fact that high lift creates added strain on the valve train and can cause valve float.
So how do we fix this? It’s actually pretty easy and straightforward. Get rid of the fixed metal programming and introduce infinitely variable programming. Get rid of the camshaft and instead create an individual high-tech solenoid for each valve. No longer is the valve opening speed a slave to the piston speed and the camshaft lobe shape. The valve now opens near instantly. It remains open as much and as long as you want whenever you want. Your only real constraint now is to avoid hitting the piston. Everything else is infinitely variable and more importantly it’s variable completely independently from each other. The end result is that you can have it all. Dramatic high rpm performance as well as low emissions and high torque and responsiveness at low rpm and low throttle openings. Throttle? What am I saying, if we can infinitely vary the valve opening we can use the valves to decide how much air comes into the engine, we don’t even need a throttle anymore. By getting rid of the throttle we improve efficiency by getting rid of the pumping losses. What are pumping losses? Try breathing through a straw. That’s exactly what the engine is doing when it’s trying to ingest air through a tiny orifice provided by a throttle butterfly that is only slightly open.
So Freevalve is obviously amazing. Why then am I saying how it’s not a big deal? It’s not a big deal because what I just did is compare freevalve to a fixed valve timing engine. And this is also what freevalve has been doing themselves.
A special thank you to my patrons:
Daniel
Pepe
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Peter Della Flora
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Joe C
Zwoa Meda Beda
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#d4a #freevalve #koenigsegg
コメント (21)
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CAN WE PLEASE all take a minute to acknowledge how GENIUSLY he explained what a cam does ... both graphically, and, by explaining that it's a physical (metallic) punchcard basically. It's basically software embedded in the hardware. And I'll bet it wasn't quick for him to make those graphics that we experienced for all of 10 seconds ... and probably took him a few hours!
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In the mid-90's in college (EE degree) we built a valve control system that was operated via electrical actuation. We wrote all the code with 68HC stuff. The code was pretty trivial. Finding mechanical solutions that worked reliably and would do so under the conditions of an engine was super difficult. We never got it to idle more then a couple minutes at a time. Fun project though.
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One possible good use for Freevalve is instead of trying to make a little engine more powerful, make a big engine more efficient and versatile. For instance, you can have a 800hp V8 monster that can also cruise around town or on the highway and get really good gas mileage when all 800hp isn't needed. That's something that wasn't covered in this video.
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Great content as always. We constantly get course requests for 'FreeValve tuning' despite the fact no one owns or has access to tune such an application! The Chinese development was exciting at the time and even though this isn't quite as magical as people believe off the cuff, I was still interested to see something come from that. If nothing else at least we got that awesome MX5/Miata build to watch 😂 - Taz,
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This brother is a genius. Explains stuff so well
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another neat trick with freevalve is that you don't need a wastegate anymore, half the exhaust valves (1 per cyl) are connected to the turbo, half past it; by varying the amount each opens you can control boost
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Also whats interesting is that Tucker made essentially a freevalve back before 1948. When he first developed an engine for what would become the Tucker 48, before he chose to use a modified helicopter engine, he was developing a 500+ cu in engine that would use a special distributor to send pressurized oil to open the valves at a timing set by the distributor. This wasnt done for performance though, as it was common back then to puncture your oil pan and run your engine without oil, this destroying it. So tucker opted for this distirbutor oil valve tech so that your engine would shut off if it ever didnt have oil. This engine, which was going to drive twin fluid drive torque converters as a sort of CVT back then, never made it past prototyping, as it required mains voltage to crank, weighed a gargantuan amount, and wouldve been too expensive.
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I’m 50 years old and a hot Rodder ,when I’m watching these videos, I learn all kinds of new stuff .THANK YOU ever so much.
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Freevalve would have been absolutely groundbreaking and truly revolutionary... If it could have been made functional in 1990...
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Design yourself into a corner with a hundred million or so on the line and anyone will come up with a groundbreaking and revolutionary new idea. Even if it never makes it into a road car its gotten a lot of people talking about Koenigsegg for the past 10 years I'd consider that a success.
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I would love to see Freevalve used on a modernized radial engine. It would simplify the construction quite a bit not needing cam rings and such. If naturally aspirated it would eliminate any need for an intake system entirely, so between all of that it would make a multi-row radial very simple to build.
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Great explanations, great animations, great argoumentation. In 17 minutes you made clear the entire topic of freevalve. Absolutely brilliant.
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Excellent video. I think you are quite correct. Freevalve (or similar non-camshaft technologies) makes the most sense on hypercars or similar cars where the top priority is maximum performance, cost be damned. What Freevalve does is allow the engine to reach that maximum performance over the entire rev / speed / torque range while also providing acceptable drivability at city driving speeds and also meeting emissions and fuel economy mandates.
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Absolutely top-shelf content! Thanks for providing easily-digestible content in reasonably-sized and shareable chunks! <3
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It's the first vid I'm watching on your channel and I wanted to wait until the end of the vid but I can't. You're just too good. Simultaneously very clear and very thorough, impeccable scripting and delivery... I loved every bit of it
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The Bob Ross of engines. I Love it. Thank you for the time in. Great video!
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Another brilliant vid. I really liked the idea of Freevalve and that it came from a small and innovative company and genuinely sad to hear efficiency gains etc are not too great compared to modern engines. Also, I'm annoyed that Freevalve was compared to non VVT engines by Koenigsegg, I just can't get my head around that.
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It was positive to hear about Fiat's Multiair, because I was thinking that FreeValve patented old solenoid valve idea and was monopolizing it, which is not helping the tech developement sometimes. Reliability is still the main concern, failing of electronics cannot kill a camshaft engine normally, but a freevalve engine can be destroyed.
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Incremental innovation is hugely underrated. Great to see it getting quality playtime.
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Back when BMW introduced Valvetronic on top of Double VANOS, I thought the combination was super impressive. Those engines could optimize intake and exhaust flow at almost any RPM and run with the throttle plate full open all the time, what more could you ask for? But Multiair is incredible and FIAT sort of changed the game without anybody here in the US even noticing. It basically does everything on the intake side that Freevalve can do.
