Reputable links for horsepower from windage tray/crank scraper

[ptuomov]

The elephant in the cross-plane V8 crankcase:

CrankcasePressuresPerBayPerDegree.jpg

I think that this is really the only first order issue in terms of the crankcase gas flows. There are two points in the full 360 degree crankshaft rotation cycle when the piston pumping pulses create a huge pressure differential between the front and rear bays. That's a violent event, and as far as the crankcase gas flows, pumping losses, oil being blown in wrong places by crankcase gas, it's the elephant in the room. Anything that makes that flow less violent will help and anything that forces that flow to happen thru a smaller area (and thus faster) is going to hurt. At least that's what I am thinking now, based on what I've read and figured out on my own.

[Kevin Johnson]

...

I'm having really hard time abstracting from the following two issues:

- The strongest normal to air flow force that I can imagine pushing something into the flow is created by the atmospheric pressure in the crankcase. Is the rotating crankshaft going to create a huge pressure inside the case? I fail to imagine that, somehow, especially after having taken pressure measurements from crankcases.

- In a river, the density ratio of stone (or sand) to water is about 2x. In the crankcase, the density ratio of oil to gas is about 700x. How is anything else but the centrifuge effect going to survive in a crankcase with that sort of density ratio? I am thinking that tea leaf paradoxes and riverbank erosion papers are completely irrelevant to the crankcase windage. The density ratios are so far off.

A lot simpler mental model for what's going inside a crankcase would be a heavy-ball mechanical lottery ball machine.

Tuomo, maybe this is related to where you grew up and natural phenomena that possibly were not common occurrences. I grew up in tornado alley in the United States and have no trouble whatsoever understanding how much denser objects can be suspended inside a spinning air flow. I used to walk countless miles in farm fields and would find all sorts of household objects that were carried aloft and then ejected miles away. Tornadoes came down our street and destroyed the homes of several of my classmates.

When I worked in California's Central Valley there were days when you could see dozens of very tall dust devils sucking dirt from the fields hundreds of feet into the air.

The Dust Bowl of the 1930s was in living memory of my friends (recall the Okie that I mentioned that was an auto mechanic in Turlock, CA).

I think hail is a common occurrence in The US and Northern Europe. I know when Samantha and I visited Germany there was a large hailstorm shortly after we arrived. I am showing raekiviä as the Finnish translation of hail stones on Google. Read how hail is formed and grows incrementally larger.

[ptuomov]

uomo, maybe this is related to where you grew up and natural phenomena that possibly were not common occurrences. I grew up in tornado alley in the United States and have no trouble whatsoever understanding how much denser objects can be suspended inside a spinning air flow.

When I worked in California's Central Valley there were days when you could see dozens of very tall dust devils sucking dirt from the fields hundreds of feet into the air.

The Dust Bowl of the 1930s was in living memory of my friends (recall the Okie that I mentioned that was an auto mechanic in Turlock, CA).

I think hail is a common occurrence in The US and Northern Europe. I know when Samantha and I visited Germany there was a large hailstorm shortly after we arrived. I am showing raekiviä as the Finnish translation of hail stones on Google. Read how hail is formed and grows incrementally larger.

I think I understand why a tornado can lift a car. There's a somewhat higher than atmospheric total pressure under the car that stagnates into a relatively high static pressure. At the same time, there's a low static pressure on top of the car. The car lifts up. The fact that tornado is a rotating thing just adds some stability to the whole thing so these conditions can last.

If we follow that analogy, we'd somehow have to have a high total pressure on the outer orbits of the crankcase that somehow stagnates to a high static pressure and pushes things towards the center. I don't see that happening either based on my elementary logic or the measurements that I've read about or taken myself.

Another thing that I am puzzling about is your disrupting air flow theory of crank scrapers placed close to the crankshaft. If we put a plate in that stream, two things will happen. First, the overall flow is reduced, which will reduce any effects. Second, the flow that remains will stagnate at the scraper and increase the static pressure that can push things towards the center. Why does the former effect dominate in your theory?

[digger]

...

I'm having really hard time abstracting from the following two issues:

- The strongest normal to air flow force that I can imagine pushing something into the flow is created by the atmospheric pressure in the crankcase. Is the rotating crankshaft going to create a huge pressure inside the case? I fail to imagine that, somehow, especially after having taken pressure measurements from crankcases.

- In a river, the density ratio of stone (or sand) to water is about 2x. In the crankcase, the density ratio of oil to gas is about 700x. How is anything else but the centrifuge effect going to survive in a crankcase with that sort of density ratio? I am thinking that tea leaf paradoxes and riverbank erosion papers are completely irrelevant to the crankcase windage. The density ratios are so far off.

A lot simpler mental model for what's going inside a crankcase would be a heavy-ball mechanical lottery ball machine.

Tuomo, maybe this is related to where you grew up and natural phenomena that possibly were not common occurrences. I grew up in tornado alley in the United States and have no trouble whatsoever understanding how much denser objects can be suspended inside a spinning air flow. I used to walk countless miles in farm fields and would find all sorts of household objects that were carried aloft and then ejected miles away. Tornadoes came down our street and destroyed the homes of several of my classmates.

When I worked in California's Central Valley there were days when you could see dozens of very tall dust devils sucking dirt from the fields hundreds of feet into the air.

The Dust Bowl of the 1930s was in living memory of my friends (recall the Okie that I mentioned that was an auto mechanic in Turlock, CA).

I think hail is a common occurrence in The US and Northern Europe. I know when Samantha and I visited Germany there was a large hailstorm shortly after we arrived. I am showing raekiviä as the Finnish translation of hail stones on Google. Read how hail is formed and grows incrementally larger.

acceleration = omega ^2 * R

a crank shaft has accelerations orders of magnitutde higher than a tornado

hell get a large twist drill dip it in oil and spin her up

[Kevin Johnson]

...
acceleration = omega ^2 * R

a crank shaft has accelerations orders of magnitutde higher than a tornado

hell get a large twist drill dip it in oil and spin her up

One of the effects of the orders higher acceleration is the formation of atomized oil droplets which are carried/influenced by the dynamic pressure differentials in the crankcase.

[ptuomov]

...

I'm having really hard time abstracting from the following two issues:

- The strongest normal to air flow force that I can imagine pushing something into the flow is created by the atmospheric pressure in the crankcase. Is the rotating crankshaft going to create a huge pressure inside the case? I fail to imagine that, somehow, especially after having taken pressure measurements from crankcases.

- In a river, the density ratio of stone (or sand) to water is about 2x. In the crankcase, the density ratio of oil to gas is about 700x. How is anything else but the centrifuge effect going to survive in a crankcase with that sort of density ratio? I am thinking that tea leaf paradoxes and riverbank erosion papers are completely irrelevant to the crankcase windage. The density ratios are so far off.

A lot simpler mental model for what's going inside a crankcase would be a heavy-ball mechanical lottery ball machine.

Tuomo, maybe this is related to where you grew up and natural phenomena that possibly were not common occurrences. I grew up in tornado alley in the United States and have no trouble whatsoever understanding how much denser objects can be suspended inside a spinning air flow. I used to walk countless miles in farm fields and would find all sorts of household objects that were carried aloft and then ejected miles away. Tornadoes came down our street and destroyed the homes of several of my classmates.

When I worked in California's Central Valley there were days when you could see dozens of very tall dust devils sucking dirt from the fields hundreds of feet into the air.

The Dust Bowl of the 1930s was in living memory of my friends (recall the Okie that I mentioned that was an auto mechanic in Turlock, CA).

I think hail is a common occurrence in The US and Northern Europe. I know when Samantha and I visited Germany there was a large hailstorm shortly after we arrived. I am showing raekiviä as the Finnish translation of hail stones on Google. Read how hail is formed and grows incrementally larger.

acceleration = omega ^2 * R

a crank shaft has accelerations orders of magnitutde higher than a tornado

hell get a large twist drill dip it in oil and spin her up

It's also that oil is a lot denser than a car. If you would fill the car completely with oil, I doubt it would be lifted by even a tornado. In fact, fully loaded trucks aren't usually picked up by tornados and partially filled trucks just flip. When one sees a truck with a trailer flying in a tornado, there's the association of it with being very heavy. However, a truck with an empty trailer has overall low density.

An offsetting effect is (I think) that smaller the oil drops get the greater the impact that air flow can have on them, as long as the oil drops are far from each other in terms of the size of gas molecules. (Now I am winging it, though.)

[ptuomov]

...
acceleration = omega ^2 * R

a crank shaft has accelerations orders of magnitutde higher than a tornado

hell get a large twist drill dip it in oil and spin her up

One of the effects of the orders higher acceleration is the formation of atomized oil droplets which are carried/influenced by the dynamic pressure differentials in the crankcase.

Is this some sort of Turing test that's happening here?

[Kevin Johnson]

One of the things that is happening here that is dangerous for humans is the now dominant attitude that if we cannot model something accurately then it doesn't exist.

I have real actual work to get done now.

[makin chips]

Seems like you all should just give up on this. Obviously ptuomov isn't going to change his opinion, no matter what Kevin posts. Jon is just poking and prodding with no real reasoning. It's going nowhere. Just back and forth and back and forth of Kevin presenting info and ptuomov saying he believes and thinks other things happen and not anything Kevin posts.


So why keep going? Seems like it's leading to the same place these all do...2 people trying to compare "brains" and see whose is the biggest

[ptuomov]

One of the things that is happening here that is dangerous for humans is the now dominant attitude that if we cannot model something accurately then it doesn't exist.

I don't rule anything out. However, when we have to do something, I think it's best to stick with what the measured data and best theories say. For example, we can rule some stuff out, like quantitatively important tea leaf effects happening in a cavity size of a crankcase when the density ratios between the substances are 700x. And when we can model something well, like the crankcase gas flows in that 2013 Chrysler paper, I think it makes sense to pay attention to results and revise opinions accordingly.

[ptuomov]

Seems like you all should just give up on this. Obviously ptuomov isn't going to change his opinion, no matter what Kevin posts. Jon is just poking and prodding with no real reasoning. It's going nowhere. Just back and forth and back and forth of Kevin presenting info and ptuomov saying he believes and thinks other things happen and not anything Kevin posts.

So why keep going? Seems like it's leading to the same place these all do...2 people trying to compare "brains" and see whose is the biggest

While I agree with you that we're going in circles, I think that statement is somewhat unfair. First, on my part, this is neither an attempt to sell anything nor an attempt to look smart. Believe it or not, I am actually trying to figure this thing out. Second, I can change my mind about things when someone has the data or a chain of logic that tells me I'm wrong. For example, before I read that 2013 paper, I also thought that the direct effects of the rotating crankshaft are meaningful in a large V8. However, after I read the paper, I contacted the authors, they gave me their data, and walked me thru it on the phone, I had to revise my views pretty significantly.

[SchmidtMotorWorks]

Seems like you all should just give up on this. Obviously ptuomov isn't going to change his opinion, no matter what Kevin posts. Jon is just poking and prodding with no real reasoning. It's going nowhere. Just back and forth and back and forth of Kevin presenting info and ptuomov saying he believes and thinks other things happen and not anything Kevin posts.


So why keep going? Seems like it's leading to the same place these all do...2 people trying to compare "brains" and see whose is the biggest

I am skeptical about claims of oil wrapping around a crankshaft like taffy.
So far, the best view presented of the a crankshaft viewed in a running engine debunks that claim.

I see nothing like what was claimed.

[SchmidtMotorWorks]

Jon, it's all a blur. Too fast for the human eye. You just believe you watched it and you saw what you wanted to see.

Keep working on orthogonality and reading comprehension.

Smokey claimed to have seen it through plastic plates on the side of an oil pan, nothing about a strobe.
I have seen windows with oil on them, you can't see much of anything through them.

[Kevin Johnson]

... Second, I can change my mind about things when someone has the data or a chain of logic that tells me I'm wrong. For example, before I read that 2013 paper, I also thought that the direct effects of the rotating crankshaft are meaningful in a large V8. However, after I read the paper, I contacted the authors, they gave me their data, and walked me thru it on the phone, I had to revise my views pretty significantly.

I thought that I pointed out (some of) the multiple errors in their logic.

Here's a biggie: They mistook elements of a subset of windage trays as defining the superset of all possible windage trays.

[ptuomov]

... Second, I can change my mind about things when someone has the data or a chain of logic that tells me I'm wrong. For example, before I read that 2013 paper, I also thought that the direct effects of the rotating crankshaft are meaningful in a large V8. However, after I read the paper, I contacted the authors, they gave me their data, and walked me thru it on the phone, I had to revise my views pretty significantly.

I thought that I pointed out (some of) the multiple errors in their logic.

Here's a biggie: They mistook elements of a subset of windage trays as defining the superset of all possible windage trays.

I may have made mistakes in extrapolating their findings too far, but I am not aware of any errors or impactful simplifications in the analysis.

For example, as a simplification, they don’t model the conrod big ends. This is a simplification, but given how little volume the conrod big ends displace, it can’t be impactful for the gas flow results. For oil flow results, it could have some impact.

So please elaborate on the errors in that paper.