Dimpled Pistons: 20%+ better (Diesel) fuel economy!??
 

Firstly; I don't 'see it', but there seem to be a good number of indipendant tests proving this works. (in Diesel engines)

Some links to get you started:
https://www.carexpert.com.au/car-new...diesel-engines

https://dfcdiesel.com/2023/05/02/how...iesel-engines/

Home Page:
https://www.speedofair.com/

Youtube:
https://www.youtube.com/results?sear...impled+pistons

I have yet to research this properly but for the moment:
IF they work; How and Why??
aerohead??

This seems pretty easy to DIY.

That closing in on 'extraordinary claims' territory.

But it reminds me of drilling holes in the piston top. www.onallcylinders.com: Part 2: Power-Packed Piston Tech You Can Use!

[Impatiently waiting to see whether to pull out drill]

Hey, that's a bad thing!

I don't know if I'd believe those "studies." "NOx reductions saw reductions as high as 80 percent, and the ability to extend oil change intervals jumped by 50 percent due to decreased soot and fuel dilution," and "15.5 percent increase in horsepower and a 15.2 percent increase in torque," seem kind of hard to believe to me.

From what I understand you could benefit from dimples but if only they're put in the right places. Just randomly guessing probably won't help. And there are other geometric changes in a combustion chamber that may help more than just dimples.

The way air, fuel and flame flow through a combustion chamber is quite complex. This is one reason why engines keep getting more efficient, the combustion chamber, piston and intake designs do better and putting air and fuel where they need to be and moving in the direction they need to be. That's a lot harder to do than one would think.

Note that the treatment also includes thermal barrier ceramic coatings, so how much of the extraordinary improvements are the dimples and how much is due to the coatings?

Maybe I'm reading the charts wrong, but @2100rpm there was 30%(?) increase in power with 6% improvement in BSFC, which means 23% more fuel was injected. It's not apples to apples and if you don't isolate your variables - you are not doing science!

https://ecomodder.com/forum/attachme...1&d=1714293303

Dimples are what you do before you have 5-axis CNC mills.

So, do we use these improvements from the dimples to efficiently move this thread to the Unicorn Corral?

' 20% '
 

I'm not current on Diesels, as I've lost interest in internal combustion, but the last time I looked, the most efficient diesels were in ocean-going cargo ships.
The one reported, was manufactured by HITACHI, of Japan, which ran on bunker fuel, was compound-turbocharged, and operated at a maximum, 130-rpm.
The pistons are as tall as an adult male.
The brake thermal efficiency is 42% ( 58% of the thermal energy is lost ).
The ships can stay at sea for 3-months per 'tank.'
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These engines would have already undergone intense investigation for combustion efficiency, and without exacting specificity, the claims of a 20% improvement in mpg would require third-party laboratories corroborating the same extraordinary evidence.
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My initial reaction to the claim is that it is highly dubious!

Ships also use the waste heat in exhaust ( and cooling system?) to turn steam engines/turbines, greatly increasing the efficiency per liter of fuel burned.

My Initial reaction is the same, but I still haven't researched this much at all.
The ceramic coating on top and low friction coating on the skirts further muddy the results.

I am interested in what you think might happen to the flame front etc when encountering said dimples..?

These dimples (size position etc) are most likely based on software developed by a Sal Rodriguez of Sandia National Labs.

New topic here:
https://ecomodder.com/forum/showthre...tml#post693139

(Unicorn that! :) )

Could be true. But from my limited perspective, I'd expect the dimples to be placed in certain areas, perhaps with different sizes. The pics looke like they were just evenly sprinkled around on the piston. If air comes blasting in from the intake valve and then is swirling around as it's compressed, I don't see an even, spread out set of equally sized dimples as being software developed. But who knows, I could be wrong.

The Speed of Air guys do carry on about how the dimples' size, shape and position is based on the say so of some or other aero software, saying that you can't just put any old dimple anywhere.
I too took that with a large pinch of salt as they want to sell pistons after all or they would also be carrying on about dimpled intakes and cylinder heads etc, which are slower moving, more expensive parts...

Now; I'm not so sure.