Water Skiing Explains LUBRICATION - This CRAZY Engine Proves It!

What do water skis, piston rings, and motor oil have in common? I'm Lake, the motor oil geek, and there are three stages of lubrication, and these water skis can explain every one of them. Imagine when the boat's not moving, where's the water skier? Down in the water. But then as the boat begins to move away, what happens to the skier? They begin to come out, but they're not fully out of the water yet. They're kind of halfway in, halfway out in this mixed condition. But then as the boat reaches speed, the skier's fully up out of the water. In lubrication, that's full film hydrodynamic lubrication, just like your engine bearings. That mixed condition is when there's only partial oil film. There's still some peaks from both surfaces that can still contact each other. It's a mixed condition. But when that skier was still in the water and the boat wasn't moving, that is boundary condition. And there's more friction and wear in the boundary condition than in the mixed and in the hydrodynamic. And that's where the piston rings come into play, because piston rings experience all three stages of lubrication in every single cycle. If you think about that piston, when it's at mid-stroke, it's going as fast as possible. It's in that full film condition. But as the piston nears top dead center, it has to begin to slow down. That's where it transitions into that mixed film condition. But then at top dead center, at ring reversal, it transitions into that boundary condition, which is why there's more wear at the top of the cylinder than in the middle of the cylinder. And there's a thing that's called the Strybek curve that shows all of that. That as the skier comes up out of the water, if you will, you move from boundary condition into mixed into full film hydrodynamic. Since this channel is all about the science and not speculation, let's go down to Texas and show you a very special engine that can prove all of this. So here we are in Texas with Dr. Dimitri Gardelis. I'm just going to call you Dr. D. Is that okay? That sounds good enough to me. Boundary condition, mixed film, hydrodynamic, the three stages of lubrication that the Strybek curve tells us influence both friction and wear. Why don't you explain how your very unique, super cool engine actually proves these little piston rings actually experience all three stages of lubrication? So mid stroke, the piston ring is moving quickly. There is very little pressure behind it. So the piston ring rides in a nice film of oil, no friction, no wear. The cross patch finish does not get disturbed in the middle part of the cylinder. No problem. Coming to the top of the cylinder, the pressure goes up, the speed goes down. So from about minus 30 degrees before top dead center to about plus 45 degrees after top dead center in typical engine, the piston rings start touching the liner and grinding against the liner, increasing the friction coefficient by a factor of 10, perhaps more. The same thing with the piston skirt. The piston skirt is not moving close to top dead center. And yes, exactly at top dead center, the connecting rod is perfectly perpendicular, but slightly after top dead center, you have the peak cylinder pressure and the combination of the peak cylinder pressure and the angularity of the connecting rod creates a very high contact force between the piston skirt and the cylinder. Both of these combined create a very large friction loss on the engine. There's big advantages to making this liner spin. So why do we spin the liner? We knew the slivov engines from the old past that they're rotating the cylinder for completely different reasons. And they figured out that rotating the cylinder is actually eliminating the wear at the top of the cylinder and maybe there's an advantage. So the idea is we take this concept and we rotate the cylinder without the reciprocation of the slivov engine and let's see what happens. Because the slivov, it didn't fully rotate. It didn't fully rotate, but they rotated at the right time. They rotated the sliv at the right time at top dead center. At first, they didn't realize why they were doing this. They were doing this in order to make the ports match and having the maximum flow. And then they realized, well, there's an advantage to that. So based on that idea of the slivov, that kind of gave you the inspiration to see what happens if you just rotated the liner constantly. Only for the purpose of reducing friction and wear. Let's leave the valves where they belong in the head because everything has been optimized to meet emissions with the valves in the head. Let's not worry about the added emissions of the sleeves and the ports and all that. And let's design everything and optimize everything specifically to reduce the parasitic friction of the rotating liner and minimize the drag from the boundary friction of the conventional cylinder and piston. So the idea is you're rotating this liner and you're doing it in series. At constant speed, unlike the slivov engines. So this thing is focused on rotating the cylinder and it protects both top dead center and bottom dead center. So what's neat is so you can just basically drive this and it just rotates. And right now in this prototype, this rotates three to one ratio to the crankshaft. Unlike the slivov that were stuck on a specific ratio to keep the ports happy, here we can choose the ratio. So one other little neat tribological fact about this is not only are you making the liner rotate, so therefore it's moving the piston rings out of boundary condition, you also have to create a very unique thrust bearing here to seal it. It's like an axial piston ring. So it has the same elements of a piston ring, but it seals on the axial direction and the force is on the axial direction. But if the seal, if this seal does not operate in the hydrodynamic regime and it doesn't operate with low friction, then you're wasting your time. So we have designed and developed a seal here that has very low friction and pretty much no blow-by, no additional leakage. So this works just like a head gasket, allowing the cylinder to rotate. That's what's really cool is that this is, there's so many little details about this engine that are so fascinating. This is like tribology in action and I love tribology and this is so freaking cool. This is amazing. It's an engine focusing on tribology. Most engines focus, most test engines or experimental engines focus on the thermodynamic side of an engine. Here we're only focusing on the, on the, on the tribological side of the engine, leaving the thermodynamic exactly the way it is from the factory. Okay, awesome. Okay, before we move on, because we, I want to be able to show the data, right? We said in the very beginning of the video, this is science, not speculation. So we need to show you the data of, to prove this out. We showed you the mechanical workings, but we're going to show you the data in a little bit. We will. So the question is, we do remove this metal-to-metal contact friction. How much is it really? Right. What's the, what's the value of making this liner rotate by moving it out of the boundary condition and into hydrodynamic, both on the piston moving up and down and the seal, so we're not introducing extra drag. What's it actually worth? So let's go to the lab and show us how you instrumented the engine to be able to prove that. Fun fact, the company that invented that sleeve valve engine was called Napier. The same Napier that invented the hook style second piston ring. You see, you can't escape piston rings when it comes to tribology. Okay. Dr. D, where are we? We're at the basement of the engineering building where we have our baseline engine, which is right now installed on the dyno. And all the instrumentation is hooked up the way we took our measurements. And what measurements do we have? We can start with encoder, crankshaft encoder, which is sitting right here, this encoder box. And this guy measures crankshaft position 20 times for every crank angle degree. So super accurate location. So that sends a computer a signal where the crankshaft really is. And then we have a pressure transducer on the cylinder head that measures the instantaneous cylinder pressure. So the computer knows exactly what the cylinder pressure was. We go through the cycle, instantaneous pressure, instantaneous location, instantaneous volume. The volume is really what's important. And you integrate volume with pressure and you get what we call mean effective pressure, which is essentially torque of the engine right before the friction. And then we have to measure what we call brake manufacturing pressure, which is the friction that the engine really produces. And that is done on the dynamometer. The dynamometer has a moment arm. And on the moment arm, there is a load cell that creates the force times the moment that gives you the torque. And that also is fed to the data collusion system. So from this, we can get instantaneous BMP, instantaneous MMP. The difference is FMMP. Interesting with this engine is because... So FMMP is the friction. The FMMP, friction. BMP, brake mean effective pressure. Why did they call it brake? Because in the old days, brake was what the dyno, they didn't really have real dynos, they had a real brake. So that got stuck, brake. And indicated is because in the old days, they used to have a little pen that was actually writing the thing. Now we're a little bit better than that, but the name stuck. So IMMP minus BMP equals FMMP. So the engine is identical to the other engine. The conditions are identical. So the friction benefit that we get is the real benefit of this. So now we can isolate from the system what is the boundary contribution. So you ran this engine, the baseline engine with a standard liner, not rotating. And then you put the rotating liner engine on it and you ran basically the same test sweeps. So you ran a IMEP sweep. So you know how much power the engine is making in the cylinder. Then you're able to extract out the delta difference at the brake between the two. And that tells us how much friction we're saving and how much friction is really in the engine under high load. So the question is how much boundary friction does exist? Because obviously when rotating the liner, you're not in boundary anymore because you have that hydrodynamic wedge being able to be formed because the piston ring isn't moving anymore, but the liner is. So you still have that differential of relative motion creating the oil film. How much was it? 0.8 bar at 7 bar and about 0.4 bar at 0 bar. Sorry, 7 bar IMEP. We're saving 0.8 bar. Okay. That's roughly a little over 10 percent. 10 percent. That's massive. And this is of course a part load. The number in absolute number is going to go up as a higher load, but the percentage is going to drop a little bit. Right. So at idle, the engine is going to be consuming about 40 percent less fuel. At third load or half load for a commercial engine, we're going to be consuming about 10 percent less fuel. This is massive. I mean 10 percent is huge when you're talking about big fleets. And even in a tiny little engine like this operating as a generator, you can be saving $50,000 a year without too much trouble. This could be really incredible efficiency for you if you're watching this video or whoever else may be interested in this technology because it's game-changing technology in terms of reducing the friction in the engine. But also you got to learn how the Stradbeck curve works. The three stages of lubrication are real and that every engine, well not every engine experiences them. You can fake your way around it if you use some pretty clever technology. So if someone's interested in this technology, how do they reach out to you? Please send me an email. Reach out to me at rotatinglion.com. We'll leave that linked in the description box below. I can't thank you enough for letting us peek inside this amazing engine and see this cool project. Thank you for hanging out and watching this. 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