Cool piston tech

jimbote

Certified Volkswagen Nut
Joined
Jul 10, 2006
Location
spiral arm, milky way (aka central NC)
TDI
Tacoma 4x4 converted to TDI

GlowBugTDI

Veteran Member
Joined
Jul 20, 2018
Location
Cambridge, MN
TDI
2001 Beetle GLS TDI (BIODSL). 01 original Glow Bug TDI (sold)
Very interesting.
Who knew golf balling a piston could increase FE and power.

Redgreen did this years ago on the exterior of a car to improve FE. If I could find the episode I'd post it but can't seem to find it.
 

JELLOWSUBMARINE

Veteran Member
Joined
Mar 3, 2014
Location
yes
TDI
2011 Jetta Sportwagen, 6M, red/tan, navi, pano, 83 5m diesel pickup, 82 p/u trailer,.04 5.5 TDI Passat wagon (gone), 80,81,82 diesel p/u (gone), 80,82 sportruck (gone), 59 passthru bus (long gone), 79&87 westy (gone), 57 baja bug (long gone), 73 914
Hmmmm...
 

turbodieseldyke

Veteran Member
Joined
Jun 6, 2010
Location
Free Mustache Rides
TDI
98 jetta
The operating principle may not be the same as the aero drag reduction. It's probably just a simple effect of increasing the piston surface area.

Reading the article...
The fuel savings alone, documented by independent commercial users, are as much as 25 percent and more
Which is it? Is it as much as 25% or is it more?
Hoo boy, this reminds me of the "vortex air intake" and other scams that claim to save "up to 30% in your mpgs". Magnets on the fuel lines.

Hopefully this is real. It would be cheap enough for someone to try, if they've already removed their head and have some spare pistons to test it on. Unless the surface needs to be re-hardened, that would complicate things. (edit: better to test the principle out on a gas engine, rather than a TDI that's no longer being manufactured)

The ultimate validation would be for manufacturers to use it to increase their fleet averages. ... which will cause bureaucraps to increase their increased requirements even sooner.
 
Last edited:

JELLOWSUBMARINE

Veteran Member
Joined
Mar 3, 2014
Location
yes
TDI
2011 Jetta Sportwagen, 6M, red/tan, navi, pano, 83 5m diesel pickup, 82 p/u trailer,.04 5.5 TDI Passat wagon (gone), 80,81,82 diesel p/u (gone), 80,82 sportruck (gone), 59 passthru bus (long gone), 79&87 westy (gone), 57 baja bug (long gone), 73 914
I'm not sure the "myth busters" did that well on their golf balled car body. I did however miss the muffler bearing episode
 

dhangejr

Veteran Member
Joined
Mar 1, 2017
Location
PNW is my home
TDI
mk4 Jetta
The operating principle may not be the same as the aero drag reduction. It's probably just a simple effect of increasing the piston surface area.

Reading the article...

Which is it? Is it as much as 25% or is it more?
Hoo boy, this reminds me of the "vortex air intake" and other scams that claim to save "up to 30% in your mpgs". Magnets on the fuel lines.

Hopefully this is real. It would be cheap enough for someone to try, if they've already removed their head and have some spare pistons to test it on. Unless the surface needs to be re-hardened, that would complicate things. (edit: better to test the principle out on a gas engine, rather than a TDI that's no longer being manufactured)

The ultimate validation would be for manufacturers to use it to increase their fleet averages. ... which will cause bureaucraps to increase their increased requirements even sooner.
It did not say more than 25% it said as much as. Which means that’s the max. So probably

I agree it sounds too good to be true , time will tell. however anytime combusting is simplified (or made more efficient) economic factors should be increase.

I wonder how long the “anti-friction coating will last and what the effects will be when it wears off”
 

turbodieseldyke

Veteran Member
Joined
Jun 6, 2010
Location
Free Mustache Rides
TDI
98 jetta
It did not say more than 25% it said as much as. Which means that’s the max. So probably
I quoted the article, "as much as 25% and more". If their testers report 26% or 30 or whatever, why not just print the higher number?

Anyway it seems to me if it's legit, they would be selling hard to manufacturers, not niche markets. Patent royalties worldwide would be astronomical.
 

dhangejr

Veteran Member
Joined
Mar 1, 2017
Location
PNW is my home
TDI
mk4 Jetta
Yeah, I know you quoted the article..

FWIW, my interpretation of the words you Quote “as much as” does not imply any more than 25% as you suggested. Instead it implies up to 25 %
In other words they were able to see UP TO 1/4 improvement in efficacy, sometimes…

I get what you’re saying but the fact is they almost certainly seen a variable range of efficient improvements. The best they seen was 25%

what was the lowest ?
Probably 0 or perhaps even a decrease ?!

that is the crux of the problem with statistics and quoting them in general (without the rest of the data or fuller explanations from the reporters) they are cherry picked and manipulated. I’d wonder how often they seen “as much as 25%” gains. Was it once? How many tests were done. What other observations on economic performance was recorded? The data set is certainly incomplete, like most everything else in the human world.
 

jmodge

Top Post Dawg
Joined
Jun 18, 2015
Location
Greenville, MI
TDI
2001 alh Jetta, RC2 w/.205's 5speed daily summer commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/.216's winter cruiser, 1996 Tacoma ALh
Interesting

The dimpling is used in high performance head porting.

That was interesting to see the photos of piston carbon, but they didn't show the ones that came out of the CAT, gas engine instead.

A good point up there about marketing manufacturers. If it helped emissions, FE, and longevity considerably, thus possibly costs due to emissions warranties, I would think they would have been all over it by now. At least for fleet/ cargo hauling applications.

I would like to know what red green thinks of this and what his real life applications have concluded before I buy in though.
 

jmodge

Top Post Dawg
Joined
Jun 18, 2015
Location
Greenville, MI
TDI
2001 alh Jetta, RC2 w/.205's 5speed daily summer commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/.216's winter cruiser, 1996 Tacoma ALh
There was also a link to an article about a Duramax 2.8 diesel powered S-10, not for sale in the states of course.
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
Not for us, unfortunately. The new International 13L diesel is available, and that is a rebadged Scania/MAN/VAG engine since VAG bought Navistar and rolled it into their Traton truck division. So, if you want a new VAG diesel, you can kinda sorta in a proxy way get one. :D Nothing small about it, though... and I think they are all automatics (automated manuals).
 

jmodge

Top Post Dawg
Joined
Jun 18, 2015
Location
Greenville, MI
TDI
2001 alh Jetta, RC2 w/.205's 5speed daily summer commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/.216's winter cruiser, 1996 Tacoma ALh
I would love to see more small and medium size diesel trucks.
I’d definitely buy one, as long as it didn’t have lane assist, a TV, and in general think for itself.
 

jmodge

Top Post Dawg
Joined
Jun 18, 2015
Location
Greenville, MI
TDI
2001 alh Jetta, RC2 w/.205's 5speed daily summer commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/.216's winter cruiser, 1996 Tacoma ALh
I met and talked to someone at a Woden boat show in the upper Peninsula last August that had a street legal registered Roxon. It had a few updates that I don’t remember. But the fact that it had plates drew me to it, and as I stood there looking it over the owner came up. A business over in the Gaylord area did the necessary work for him. It wasn’t Whitbread, but right in his neck of the woods.
 

GlowBugTDI

Veteran Member
Joined
Jul 20, 2018
Location
Cambridge, MN
TDI
2001 Beetle GLS TDI (BIODSL). 01 original Glow Bug TDI (sold)
The operating principle may not be the same as the aero drag reduction. It's probably just a simple effect of increasing the piston surface area.
Sorry I should have implied that more. Redgreen is a bit of a comedian so I was just implying that he tried "the tech" first. It was supposed to be slightly sarcastic, comedic, and oddly true but rereading it now I clearly didn't do a good job lol.
 

turbobrick240

Top Post Dawg
Joined
Nov 18, 2014
Location
maine
TDI
2011 vw golf tdi(gone to greener pastures), 2001 ford f250 powerstroke
From this SAE paper it sounds like these pistons may increase both fuel efficiency and soot formation. Seems counterintuitive, but the increase in soot may be why manufacturers haven't jumped on board.

 
Last edited:

Windex

Top Post Dawg
Joined
Apr 1, 2006
Location
Cambridge
TDI
05 B5V 01E FRF
Nothing small about it, though... and I think they are all automatics (automated manuals).
Technicality, but I would say they are now automatics. The first Eaton autoshift transmissions were "automated manuals" as Eaton slapped an X-Y shifter in place of the manual stick, and a clunky bolt on electric clutch actuator.

They've finally transitioned to true purpose-built automatics, meaning they were designed as automatics, not some redesigned manual transmission.

Automatics in HD trucks are no more "automated manuals" than a DSG is an automated manual in a Jetta.
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
Yeah, I suppose it is really just case of semantics. The internals are more akin to a conventional manual gearbox... input shaft, gears, output shaft, and linked to the engine via a clutch/pressure plate/ flywheel, vs. what I think of when I think conventional automatic... fluid drive torque coupling, planetary gearsets, wet clutch stacks, etc. Because there are those types of automatics in big trucks, too, but usually limited to lesser loads like straight trucks running cement mixers and things. Not these big giant semi trucks. But yeah, regardless were designed for automatic shifting from the get-go.

From the standpoint of durability, though, the difference is worth noting. I doubt these big semi units will need rebuilding constantly like the conventional automatics do.
 

JELLOWSUBMARINE

Veteran Member
Joined
Mar 3, 2014
Location
yes
TDI
2011 Jetta Sportwagen, 6M, red/tan, navi, pano, 83 5m diesel pickup, 82 p/u trailer,.04 5.5 TDI Passat wagon (gone), 80,81,82 diesel p/u (gone), 80,82 sportruck (gone), 59 passthru bus (long gone), 79&87 westy (gone), 57 baja bug (long gone), 73 914
Sippet from the article sounds just like the principle behind Hydrogen addition. More complete combustion. Still seems like such a fix all miracle pill.

Some more info.
- rather than simply masking it through the use of various after-treatment systems. “The answer is to take care of it at its source, in the combustion chamber" -
 

atc98002

Veteran Member
Joined
Nov 24, 2006
Location
Auburn WA
TDI
2014 Passat TDI SEL Premium (sold back), 2009 Jetta (sold back), 80 Rabbit diesel (long gone)
From this SAE paper it sounds like these pistons may increase both fuel efficiency and soot formation.
That's interesting, since the original article is claiming a 50% reduction in soot, at least within the lubricating oil of the engine. I don't think they made any specific claims about the exhaust. The second linked article mentions measured exhaust emissions, but made no comparisons to an unmodified engine, so I don't know the meaning of the numbers in context.
 

jmodge

Top Post Dawg
Joined
Jun 18, 2015
Location
Greenville, MI
TDI
2001 alh Jetta, RC2 w/.205's 5speed daily summer commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/.216's winter cruiser, 1996 Tacoma ALh
From this SAE paper it sounds like these pistons may increase both fuel efficiency and soot formation. Seems counterintuitive, but the increase in soot may be why manufacturers haven't jumped on board.

From the first article,
.. In a previous study, a new DSL bowl was designed using non-combusting computational fluid dynamic simulations. This improved DSL bowl is predicted to promote stronger, more rotationally energetic vortices than the baseline DSL piston: it employs shallower, narrower, and steeper-curved dimples that are placed further out into the squish region. In the current experimental study, this improved bowl is tested in a medium-duty diesel engine and compared against the SL piston over an injection timing sweep at low-load and part-load operating conditions. No substantial thermal efficiency gains are achieved at the early injection timing with the improved DSL design, but soot emissions are lowered by 45% relative to the production SL piston, likely due to improved air utilization and soot oxidation.
 

turbobrick240

Top Post Dawg
Joined
Nov 18, 2014
Location
maine
TDI
2011 vw golf tdi(gone to greener pastures), 2001 ford f250 powerstroke
From the first article,
.. In a previous study, a new DSL bowl was designed using non-combusting computational fluid dynamic simulations. This improved DSL bowl is predicted to promote stronger, more rotationally energetic vortices than the baseline DSL piston: it employs shallower, narrower, and steeper-curved dimples that are placed further out into the squish region. In the current experimental study, this improved bowl is tested in a medium-duty diesel engine and compared against the SL piston over an injection timing sweep at low-load and part-load operating conditions. No substantial thermal efficiency gains are achieved at the early injection timing with the improved DSL design, but soot emissions are lowered by 45% relative to the production SL piston, likely due to improved air utilization and soot oxidation.
That's actually from the second article/study. It sounds like the results vary depending on dimple layout, injection timing, load, and squish area. And probably additional factors. Sounds more promising than fuel line magnets, but until it shows up in use by the major manufacturers, I wouldn't get my hopes up too much.
 

jmodge

Top Post Dawg
Joined
Jun 18, 2015
Location
Greenville, MI
TDI
2001 alh Jetta, RC2 w/.205's 5speed daily summer commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/.216's winter cruiser, 1996 Tacoma ALh
Yes, It was the second article published, about an upgraded design. I meant it was the first article in the order in your post.
 

turbobrick240

Top Post Dawg
Joined
Nov 18, 2014
Location
maine
TDI
2011 vw golf tdi(gone to greener pastures), 2001 ford f250 powerstroke
The first article I linked to said this:

The results suggest that the DSL (dimpled stepped lip) piston is capable of enhancing vortex formation compared to the stepped-lip piston at near-TDC injection timings. The sensitivity study led to the design of an improved DSL bowl with shallower, narrower, and steeper-curved dimples that are further out into the squish region, which enhances predicted vortex formation with 27% larger and 44% more rotationally energetic vortices compared to the baseline DSL bowl. Engine experiments with the baseline DSL piston demonstrate that it can reduce combustion duration and improve thermal efficiency by as much as 1.4% with main injection timings near TDC, due to improved rotational energy, but with 69% increased soot emissions and no penalty in NOx emissions.
 

jmodge

Top Post Dawg
Joined
Jun 18, 2015
Location
Greenville, MI
TDI
2001 alh Jetta, RC2 w/.205's 5speed daily summer commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/.216's winter cruiser, 1996 Tacoma ALh
Ok, I see now, they came out in a different order when I opened them both before reading them.
 

[486]

Top Post Dawg
Joined
Mar 1, 2014
Location
MN
TDI
02 golf ALH
"speed of air"
rofl
the company that'll build you a couple several-thousand-dollar k03 turbos from a 1.8t passat for your 8.1 liter chevy in a lifted truck on michelin XMLs "our patented geometry and coatings make it blah blah blah"

They're snake oil salesmen.
 

DuraBioPwr

Veteran Member
Joined
Jan 28, 2020
Location
Eastern Washington
TDI
2004 BEW Jetta (5spd)
If it works kind of a big deal. Combine that tech with Ducted Fuel Injection that Sandia is playing with and maybe no more DPFs/DEF??
 

turbobrick240

Top Post Dawg
Joined
Nov 18, 2014
Location
maine
TDI
2011 vw golf tdi(gone to greener pastures), 2001 ford f250 powerstroke
There's no way they'll get particulate emissions low enough to not need DPFs. That would require loosening of the regs- which, let's face it, ain't gonna happen. If these dimpled pistons have any merit the manufacturers will be all over it. So far, nothing.
 

DuraBioPwr

Veteran Member
Joined
Jan 28, 2020
Location
Eastern Washington
TDI
2004 BEW Jetta (5spd)
Well at one point gassers had smog pumps (air injection into manifolds) and EGR. Not any more.

We can hope, but yeah the regs are tight and it would be a huge stepwise in tech to be able to not have DPFs
 
Top