The World's First CVVD Engine - Genius!

hello everyone and welcome in this video we are learning about the world's first C V V D engine which stands for continuously variable valve duration this technology is currently used in the 1.6 liter turbo engine of the 2020 Hyundai Sonata now this is a very cool technology but in order to understand how it works we need to understand how valves work so here we have a simple single cylinder engine and of course you have your four strokes intake compression power and exhaust so during the intake stroke you open up your intake valve to allow air to enter in the cylinder same thing for the exhaust to allow that air to escape you open up the exhaust valve so the air can travel out now on the most basic of engines everything about how that valve opens and closes is fixed because the valve opens and closes based on the path of the cam profile which does not change but on modern engines there's actually three variables as it relates to valves that we can change so valve timing we're changing when do we actually open up this valve earlier or later valve lift we're changing how much do we actually open up the valve a little bit or a lot and then finally what Hyundai is adding to the mix here is valve duration so do we open it for a very short amount of time or do we open it for a long amount of time so graphically here's what this looks like we're looking at time verses valve lift and with variable valve timing as you can see you can shift where that profile occurs that cam profile causing the valve to lift up and so you can shift that left or you can shift it right with variable valve lift you can actually shift how high does the valve actually open or how low does the valve actually open and often this will also change duration as well however not independently so independently changing variable valve duration you're changing how wide is that cam profile or how narrow is that cam profile and that reduces or increases how long the valve actually remains open now I already have a video going into great detail of how variable valve variable valve lift work if you're interested so in this video we're purely going to focus on variable valve duration up until this point no mass-produced engine has been able to continuously vary how long a valve remains open relative to engine speed and you might be wondering about Koenigsegg free though we will get into that later on in the video so how does Hyundai do it well let's start with the valve and then work our way backwards so here you can see the two valves for a single cylinder these are both intake valves and above that intake valve we have our camshaft and so you can see as that camshaft and the cam there rotates it forces this rocker arm to pivot and as this rocker arm pivots it forces the intake valve open and then as the cam profile passes past that rocker arm a spring forces that intake valve to go back up so if we had an operating four-stroke engine the cycle would look something like this first we would have our intake stroke then we would have our compression stroke then we would have our power stroke then we would have our exhaust stroke and then the cycle would repeat itself now what's very special about this setup is that the camshaft and the cam lobe are not directly attached so you can see this little line right here on the camshaft and then you can see that black dot on the cam lobe and so as it rotates you can see their position always remains the same they're both always pointing the same direction however I can change their relative positioning by rotating this knob and so as you can see now when it rotates around their relative speeds are actually different at any one given point in time alright so what I'm able to do by rotating this knob is change the position of this wheel and by changing that position of the wheel you can see I change the valve duration so here at the bottom you can see those three little dots and that's to help visualize seeing this wheel move left or right and so look at what happens with the cam lobe versus the camshaft and so with the position all the way on the left here you can see the camshaft actually moves past that dot the line moves past the dot meaning up the camshaft is rotating faster than the cam lobe but then once we get to our intake valve you'll see that dot passes by the line so the cam lobe is actually moving quicker than the camshaft meaning our valve duration is actually shorter now if I move this all the way to the other end you'll notice the opposite occurs so our camshaft is now being passed by the cam lobe meaning up top the cam lobe is moving quickly but once we get down to our intake valves that cam lobe slows down and as you can see the camshaft speed remains the same but the cam lobe has slowed down and so your valve duration actually increases now if we take our positioner and go back to the center then once again they are both rotating together the entire time and remember both the camshaft and the cam profile always have the same rpm the thing that's changing is through that one revolution their relative speeds will change so in the course of a minute they'll spin around the exact same number of times however by changing this positioner the relative speeds through that one revolution is what's actually changing okay so I'm going to do my best to show these side-by-side and you can see that on the left the amount of time the valves remain open is significantly less than the amount of time the valves remain open on the right and all of this is done simply through changing positioning okay so mechanically how do you change the relative speed of the cam lobe versus the camshaft so let's start with the big picture and then work our way down to the details so first we have an actuator and this is going to be electronic however in this case we have a little hand crank to show it working so as this actuator rotates this shaft right here you can see there's a worm gear which is causing the positioner to rotate so that's essentially doing the same thing as this positioner right here so as I rotate this it positions the cam wheel left or right as I rotate this it positions the can we left or right so now we need to figure out how does positioning this wheel left or right cause the cam lobe to have a different speed from the camshaft so the key to understanding this will require an animation that Hyundai has sent what we're looking at is a simplified version of the linkage between the camshaft in purple and the cam lobe which rotates with the blue cylinder the camshaft speed will always be the same so as we rotate the assembly every 90 degrees you'll notice that in all scenarios the purple shaft is always pointing in the same direction meaning it's always rotating at the same speed this is our camshaft the camel lobe is attached to the blue shaft so first let's analyze the simplest setup in the middle here you'll notice the blue and purple shafts are always rotating at the same speed and that's because the orange linkage center point is also the center point for the camshaft but what if you move that orange center point to the left well that gives us our left most example as you can see that causes the blue shaft to move very slowly when it is on the left side and very quickly when it is on the right side if you look at the rightmost example where the orange linkage center point is to the right of the camshaft center point you'll notice the camshaft moves very quickly on the left side and very slowly on the right side so as an example if you were to place an intake valve to the left of the leftmost camshaft it would have a very long duration if you were to place an intake valve to the left of the rightmost camshaft it would have a very short duration so that's exactly what this mechanism is doing it's using a linkage which alters its rotational Center as you position it left to right which causes the cam to have a relative speed difference versus the camshaft so what does this mechanism actually look like well here you can see a glimpse of it on the model as I rotate the knob left to right you can see that position changing but it's easier to see by taking apart the actual camshaft so here we have our camshaft and as you can see three of the cylinders cams are perfectly intact and then one of the cams for one of the cylinder has been removed from this camshaft so now let's look at how the forces pass through this so ultimately a timing chain is what's going to cause this entire camshaft to rotate and then you can see we have a hole right here and so this slider goes into that slot so now the camshaft forces this slider to rotate now that slider is attached to a wheel and so that wheel is now forced to rotate from the slider which rotates from the camshaft and then another slider is placed into this side of the wheel and so now once again power comes from the camshaft all the way to this final slider here and then finally we put our cam on and so this slides on and goes into that groove right there so now the whole system is driven by the camshaft however the rotational speed is disconnected so you can see that I can rotate the cam without rotating the camshaft so once again if I remove that cam and the wheel you can see the linkage inside which allows for that relative speed differential so the camshaft remains exactly in place and you can position the wheel left or right now you can overlay the actual parts onto the simplified animation to see how this all ends up working slide the wheel to the left or right and the linkage center point changes altering the valve duration now here's where the lovely YouTube commenters come in and let me know that this system is far too complicated and there's no way it could be reliable because after watching a quick video on the Internet you certainly know more about this technology versus the engineers who spent nine years developing it yes nine years to develop this technology nine years that went into you know creating it testing it making sure was reliable by the way it comes with a 10 year 100,000 mile warranty you also might have noticed the holes and grooves on the mechanism as I taking it apart as there are oil lubrication ports throughout the camshaft to keep everything running smoothly Hyundai also has a system in place to ensure that when these parts are manufactured their tolerances all match up for the final assembly what's also cool is this is a purely mechanical system for something to fail something must fail mechanically meaning a part has to actually break for things to go wrong with design material selection part sizing and lubrication you can minimize the chances of failure my ultimate point here being you and I cannot tell simply by looking at this how reliable the system is going to be I don't have the data to prove one way or the other so there's no reason for me to just simply say it's not going to be reliable and I'm going to assume that Hyundai did their homework and ultimately time will tell us whether or not these things actually pan out to be reliable ok so what's the actual benefit of this system well Hyundai says it allows for up to 5 percent better fuel economy up to 4 percent better performance and up to 12 percent reduced emissions so how does this system actually increase horsepower well think about your two different extremes here so if your intake valve is only open for a very short duration you don't allow for much air to actually enter the cylinder so you can't make that much power but likewise if you leave it open for far too long then the Pistons gonna start working its way back up pushing the air back out of the cylinder and thus you're not going to have as much air and thus you can't make as much power so somewhere in the middle is going to be that ideal duration for the valve to remain open and that duration changes depending on what RPM you're at so at any given load at any given rpm there is an ideal there is a peak to how much power you can make for that given RPM depending on duration and so what you want to do with that duration is optimize it for every single rpm not just one or two which is what most engines will do if they have variable valve lift then you know they've got two different durations that they can choose between so the beauty of this system is its flexibility and allowing you to optimize at any rpm and thus improving horsepower across a wide range from an efficient see standpoint allowing for really long valve durations means you can run the Atkinson cycle so as that piston is moving back up during the compression stroke you leave the intake valve open pushing out some of the air and fuel and thus your compression ratio is smaller than your expansion ratio and this is a more efficient way for the engine to operate and again that timing will be dependent on rpm so a specific valve duration will be optimal for running maximum efficiency at any given rpm and any given load now emissions are improved by altering valve timing and duration to ensure that when you have a cold start of your engine the catalytic converter heats up as quickly as possible now from the very beginning of this video you may have been wondering wait a minute what about Koenigsegg is free valve this system can completely vary valve duration and it is a very cool technology although we haven't yet seen it used in a mass-produced vehicle but it does have its advantages so I asked this question to Hyundai you know why not use a system like free valve and they gave me three reasons first of all cost that's always going to be a reason towards not adopting certain technologies if it's too expensive ultimately in the long run and will end up happening second of all efficiency so they had concerns about how much energy does it take to actually run the valve system versus how much energy benefits do you receive from that valve system and if that trade-off doesn't work out it may not be worth doing and then the final concern was around reliability so Hyundai wanted to have a purely mechanical system so that the event of a failure was caused purely by a mechanical failure that's something that's fairly easy to predict through you know EFI a through design through testing and so those are the three reasons that they gave me for why they didn't choose to use a system like free valve now this doesn't necessarily mean that this is a better or worse system overall we're just looking at the logic of why Hyundai went the route that they did and it's very cool to see this technology actually end up in a production engine so if you'd like to learn more about variable valve timing variable valve lift or Koenigsegg free valve I have additional videos on those topics thank you all so much for watching and if you have any questions or comments of course feel free to leave them hello

Channel: Engineering Explained

Views: 2,265,828

Rating: 4.9227276 out of 5

Keywords: new engine, gasoline engine, turbocharged engine, genius engine, best engine, best gasoline engine, engineering explained, cvvd engine, worlds first cvvd engine, world first, koenigsegg freevalve, variable valve duration, continuously variable valve duration, cvvd, 2020 hyundai sonata, 1.6L turbo, 2020 hyundai, hyundai, sonata, 2020, new car, buy car

Id: uhsgdwUX1-w

Length: 15min 29sec (929 seconds)

Published: Wed Mar 04 2020

Reddit Comments

[u/ChickenPotPi]

It will be interesting to see if it is as reliable as Hyundai claims as well as if the youtube commentor are going to be wrong. For me I wish this technology will work but I won't touch the first model year.

[u/gdnws]

Ingenious, it takes advantage of an effect similar to that of a universal joint at an extreme angle. And since the adjuster ring is offset, you can now say that the cam lobes on that camshaft have a cam adjuster.

[u/neilww1]

Very cool to see new technologies for the internal combustion engines. This could change efficiency on older (classic cars) engines. Come on camshaft manufacturer’s, let’s show em.

[u/gator771]

Pretty nice, but I'm still waiting for Freevalve

[u/the_house_from_up]

Dailmer: The internal combustion engine cannot be significantly refined for economy.

Hyundai: We found a way to make the internal combustion engine 12% more efficient.

[u/turbodude69]

Rover VVC did the same thing 25 years ago, they gonna get any credit for this innovation?

i mean this is cool and all, but seriously.. all that work for 4% more power and 5% more fuel efficiency? doesn't seem worth the complexity.

[u/YeahNahWot]

Pulling any amount of vacuum is a waste of power. If you can get rid of having to pull a vacuum with a throttle valve to control the speed, it would be an increase in efficiency. Using the Atkinson cycle "keeping the intake valve open to get rid of compression" until you only make enough power to turn it over at any chosen speed instead. Like only needing say 50cc of air fuel mix per cycle to turn it over at idle, (instead of pulling a vacuum to slow it down) then changing to a hot cam profile to make use of full cylinder volume and harmonics to try to supercharge at any speed. (which is what hot cams try to do) Has got to be better.

[u/ExGamer44]

Very cool tech, has some potential in the race world

[u/the_house_from_up]

2020 Sonata, tune and catback be like:

https://www.youtube.com/watch?v=eew3fsFxHIY&feature=youtu.be&t=13