2 stroke thread (with occasional F1 relevance!)

All that has to do with the power train, gearbox, clutch, fuels and lubricants, etc. Generally the mechanical side of Formula One.
J.A.W.
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by J.A.W. » Thu Apr 12, 2018 12:30 am

Indeed P, effective function at that end of the 2T pulse cycle - is a matter of exhaust geometry design.

For a wide variable rpm output range an 'active' pipe shape would be desirable, but complex/expensive.

In utility machines which generally function over limited 'powerband' rpm zone, a 'green' pipe
shouldn't be too big an ask - design-wise, esp' since the 'saved' HC emissions can be utilized for doing work.

This is how the Evinrude DI outboards are predicated, with low rpm 'stratified charge' - 'eco' running,
& a closely ECU monitored 'homogenous charge' flow tune - for the high output* power zone.

*The newest marine 'HO' ETEC's feature the 'power valve' set-up as in longstanding use by smaller hi-po 2T units.
Dr Zachary Smith sez..
"Yes.. spare us your ridiculous remarks, you insensitive idiot!"

johnny comelately
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by johnny comelately » Thu Apr 12, 2018 12:36 am

J.A.W. wrote:
Wed Apr 11, 2018 12:41 pm
Pinger wrote:
Wed Apr 11, 2018 10:46 am
J.A.W. wrote:
Sat Mar 24, 2018 10:44 pm


I'd also remind you, that lubrication systems are neither 2T, or 4T in themselves, being independent
of whether every piston down-stroke is a power-stroke, or not. Many smaller 4Ts to this day, run on
a 'splash' of lube, & some even use a fuel/oil mix
J.A.W. - the last of the above, 4T running on fuel/oil mix - presumably that is the Stihl 4mix and similar you are referring to. Where? In your home country (Australia?)?

I've read about their development in American documents but no one in the UK knows anything about them. I suspect they weren't marketed in Europe (strat charge being the preference). Other than the USA, where were they sold? Why not in UK (Europe?) and why chosen rather than strat charge? Any ideas anyone?
Yeah P, its about 'good lugging power' apparently, but that's not much good for a chainsaw.. strat charge is..

https://www.stihl.com.au/4-mix-engine-l ... power.aspx
If you go back to the last century Sachs Dolmar had the best lugging power saw, when Stihl were using screaming screamers, but then sold to Makita ?? not sure what happened to them

J.A.W.
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by J.A.W. » Thu Apr 12, 2018 12:45 am

Saws & 'lugging' can be a dangerous business.. if it stalls.. so.. you've got to get 'er rippin', son!

2T's have a couple of inherent features which are valuable ( over & above power density) in this regard,
lower recip inertia = less 'kick-back' if a jam/stall does occur, plus a lower propensity to stall - than 4T's..

Even users of lawn mowers & dirt bikes - are familiar with these useful attributes.
Dr Zachary Smith sez..
"Yes.. spare us your ridiculous remarks, you insensitive idiot!"

johnny comelately
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by johnny comelately » Thu Apr 12, 2018 12:50 am

J.A.W. wrote:
Thu Apr 12, 2018 12:45 am
Saws & 'lugging' can be a dangerous business.. if it stalls.. so.. you've got to get 'er rippin', son!

2T's have a couple of inherent features which are valuable ( over & above power density) in this regard,
lower recip inertia = less 'kick-back' if a jam/stall does occur, plus a lower propensity to stall - than 4T's..

Even users of lawn mowers & dirt bikes - are familiar with these useful attributes.
I've got a six inch scar on head that says screamer 2T engines and kick back are just as bad, but I am a big supporter of 2T as you probably guessed :wink:

J.A.W.
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by J.A.W. » Thu Apr 12, 2018 1:39 am

No, Johnny, if it was a 4T, you'd likely be 6 ft under, with a cleft skull..

Those big 4T Moto GP machines have expensive ECU suites, & 'slipper' clutches to prevent highsides,
- which were routinely dealt with via the right wrist - on the far more highly tuned 500s..
Dr Zachary Smith sez..
"Yes.. spare us your ridiculous remarks, you insensitive idiot!"

J.A.W.
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by J.A.W. » Mon Apr 30, 2018 7:08 am

A recently built 'in-the-metal' & running example - of a 2-1/opposed-twin - 2T expansion chamber:

https://www.youtube.com/watch?v=-uSf-vut9KY

& see below for an early (1946) example of the sonic-flow shape, so characteristic of a tuned 2T E-C pipe..

http://www.flightglobal.com/pdfarchive/ ... 02031.html
Dr Zachary Smith sez..
"Yes.. spare us your ridiculous remarks, you insensitive idiot!"

Muniix
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by Muniix » Fri May 04, 2018 12:00 am

manolis wrote:
Wed Mar 28, 2018 3:32 pm
Hello J.A.W.

Mazda changing only the combustion achieved a 20% reduction of the fuel consumption.

https://i.blogs.es/dd64b4/mazda/1366_2000.jpg

The SkyActiv-G at left has changed to the SkyActiv-X at middle only by improving the combustion.

Is there something else that can do such a difference?


And I anticipate that the difference for the 2-strokes will be even greater.

Thanks
Manolis Pattakos
If thermal efficiency is the major goal, in identifying the TE limits of Jet Controlled CI the mid to high 50's. Controlling amount of trapped internal EGR via valve phasing, air dilution %, direct injection timing and start of combustion.

Using cylinder pressure sensors x 2, SAW sensors on the valve window gas sealing array providing a pressure reading AI Machine learning can calculate cylinder pressure when production cylinder pressure experiences Detonation artificially induced.

Using GAN AI to explore engine control and operation, especially the piston motion from offset equal to stroke. Optimising combustion phasing in defragration MiLD lambda > 1.6. Position of CA50-CA90 very important.

Seems at very low loads with a combustion chamber otherwise known not to detonate by artificially inducing it improves cylinder pressure but not the heat release. Calling it JCD Jet Controlled Detonation. Requiring features on cylinder head fire surface interacting with acoustic waves.

Operating different combustion regimes that give best TE outcomes depending on load keeps efficiency high and limiting CI to lower loads reduces engine stressed and mass. Dilution with internal EGR reduces pumping losses maintaining throttle near wide open.

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Re: 2 stroke thread (with occasional F1 relevance!)

Post by FW17 » Tue May 08, 2018 9:05 pm

Can glycerine be used as 2t oil?

J.A.W.
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by J.A.W. » Wed May 09, 2018 5:48 am

FW17 wrote:
Tue May 08, 2018 9:05 pm
Can glycerine be used as 2t oil?
Well FW17, you could buy a cheap 2T weed-trimmer, & see for yourself..

Or perhaps start by adding a sample quantity to neat fuel, to check how readily miscible - it is.

Glycerine is used as an tribological additive, & keeps rubber-type seals pliable, but it Is problematically hygroscopic..
Dr Zachary Smith sez..
"Yes.. spare us your ridiculous remarks, you insensitive idiot!"

FW17
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by FW17 » Wed May 09, 2018 4:08 pm

J.A.W. wrote:
Wed May 09, 2018 5:48 am
FW17 wrote:
Tue May 08, 2018 9:05 pm
Can glycerine be used as 2t oil?
Well FW17, you could buy a cheap 2T weed-trimmer, & see for yourself..

Or perhaps start by adding a sample quantity to neat fuel, to check how readily miscible - it is.

Glycerine is used as an tribological additive, & keeps rubber-type seals pliable, but it Is problematically hygroscopic..
Sure it wont blow up?

J.A.W.
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by J.A.W. » Sat May 12, 2018 12:32 am

FW17 wrote:
Wed May 09, 2018 4:08 pm
Sure it wont blow up?
No..

& this is why a trial - using an inexpensive/expendable machine - might be indicated..
Dr Zachary Smith sez..
"Yes.. spare us your ridiculous remarks, you insensitive idiot!"

Pinger
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by Pinger » Thu May 17, 2018 12:42 pm

FW17 wrote:
Tue May 08, 2018 9:05 pm
Can glycerine be used as 2t oil?
Why do you want to do that?

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Re: 2 stroke thread (with occasional F1 relevance!)

Post by FW17 » Thu May 17, 2018 2:14 pm

Pinger wrote:
Thu May 17, 2018 12:42 pm
FW17 wrote:
Tue May 08, 2018 9:05 pm
Can glycerine be used as 2t oil?
Why do you want to do that?
Glycerine is a good lube oil and burns clean. Wondering if it will be clean enough to get around Govt. pollution requirements

Pinger
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by Pinger » Thu May 17, 2018 4:03 pm

[/quote]

Glycerine is a good lube oil and burns clean. Wondering if it will be clean enough to get around Govt. pollution requirements
[/quote]

Depends I guess which 'Govt. pollution requirements' you have in mind but 2T oil in eg, Stihl 4-Mix engines passes the strictest tests for small hand held engines (weighted 15% idle; 85% full load). It is however, a fully synthetic oil, completely devoid of any mineral component - read hydrocarbon.
I can get confirmation (just haven't got around to it yet) from a reputable lubricant manufacturer that fully synthetic doesn't appear as UBHC during emission testing - if that is indeed the truth.

gruntguru
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by gruntguru » Fri May 18, 2018 12:23 am

"Fully Synthetic" does not necessarily mean "non hydrocarbon."

http://www.synthetic-oil-technology.info/
je suis charlie