2 stroke thread (with occasional F1 relevance!)

[manolis]

Hello all.


Qute from http://www.motorcyclenews.com/news/2016 ... lly-means/



Euro 4 affects all new models introduced in 2016, and all new bikes from 2017.

End of quote.


Quote from http://thedirtbikerider.com/ktm-enduro- ... -2-stroke/

“Also KTM had problems with euro 4 and some KTM dealers can’t anymore sell 2017 models in their country’s. But new 2018 model will come with euro 4 and it will easy pass euro 4 with elections fuel injection and lower emissions. But there is new problem for KTM, in 2020 we will have new big problem called euro5. But we all hope KTM will find solution for this and make EXC and XC models legal for street.”



End of quote



It seems that during the next two years KTM has to find a better, than the TPi, solution for the emissions of their 2-strokes.

Thanks
Manolis Pattakos

[J.A.W.]

So with direct injection how are we going to accommodate the smaller twostroke's 125 etc? Not
enough time to inject at plus 9000 rpm, or so ETech have stated. DI is only good for slower turning big capacity engines.

Actually Uniflow - AFAIR, BRP has claimed that their E-TEC system has been run successfully at 10,000 rpm,
& not many ~250cc or larger 2T cylinders in current production exceed that..
.. as for the 'tiddlers' - I guess that if there was sufficient interest, then a twin injector could be utilized..

..& BRP do have such a design under patent: https://www.google.com/patents/US6298822

[J.A.W.]

...It seems that during the next two years KTM has to find a better, than the TPi,
solution for the emissions of their 2-strokes....

Hi Manolis. I'm sure they do.. since in 'marketing' terms, the TPI is simply 'dipping a toe in the pool' 2T bike-wise..
..once the notoriously conservative & fickle motorcycle buyers are satisfied that it works, they'll be more willing..
..to 'stump up' for an even more costly/complex DI system.. ( & which KTM have had in hand, already, for years)..

& back on P. 103 of this thread ~3/4's down the page, I linked the outboard marine engine emissions figures..
..& the G2 E-TEC certainly compared well with current 4T units.. ..if 4T's cannot meet Euro 5.. then what gives..
..the 4T's.. or the emission reg's..

[manolis]

Hello J.A.W.

You write:
“.. since in 'marketing' terms, the TPI is simply 'dipping a toe in the pool' 2T bike-wise..
..once the notoriously conservative & fickle motorcycle buyers are satisfied that it works, they'll be more willing..
..to 'stump up' for an even more costly/complex DI system.. ( & which KTM have had in hand, already, for years)..”



Quote from https://transmoto.com.au/tested-ktms-2018-two-strokes/



WHAT HAPPENED TO KTM’S DIRECT-INJECTION SYSTEM?

At the launch, KTM confirmed that they had developed two main direct-injection systems for their two-strokes, but none of them managed to match the carburetted bikes’ performance – in terms of outright power, feel and sound (yep, KTM was adamant that that certain something that makes a two-stroke a two-stroke – much of which has got to do with their trademark exhaust note – was not compromised). As outlined by KTM’s Product Marketing Manager, Joachim Sauer, “We wanted to keep the rideability and engine characteristics as close as possible to our well-established carburetted engine, while eliminating the disadvantages of the carburetted engines – the need for re-jetting for different elevations, humidity, etc, for instance.

End of Quote.


The guys of KTM appear accusing their own DI systems (they have developed two different DI systems) for not being capable to “match the carbureted bikes’ performance”.

On the other hand, their(?) TPi (Transfer Port injection) cannot help keeping the exhaust port open for (say) 20 – 25 crank degrees after the closing of the transfer ports, with all the fuel already into the combustion chamber (cylinder).

The strange thing is that they achieve to comply with the euro-4 emissions regulations according which only 0.17gr of HC (Hydrocarbons) is allowed per Kilometer, which means that only about 0.7% of the fuel is lost unburnt to the exhaust (with, say, 3.5lt/100Km fuel consumption, i.e. 2.5Kg/100Km, i.e. 25gr/Km, we have 0.17gr/25gr=0.7%).



As for the E-TEC Direct Injection system of Rotax – Bombardier – Evinrude (currently the most advanced DI for 2-strokes), there are some issues at the high revs, as the additional indirect injectors (actuated above 4,500 - 5,000 rpm) prove.



The time from the closing of the exhaust port to the ignition is not adequate at higher revs (say, above 5,000rpm).

Reasonably, in the above dyno (6,700 to 8,300 rpm) the additional "indirect injectors" do "most of the work".



So, both, the TPi and the E-TEC (of Rotax, or KTM or . . .) have obvious limitations / problems / issues to address.
And not too much time to find solutions.

Better solutions are necessary.

Thanks
Manolis Pattakos

[J.A.W.]

Sorry Manolis, but I think that again - you miss the point about the 'importance' of 'marketing'..
These machines are only released ( to 'market') post significant testing for 'real world' capability..

You cannot accept at 'face value' - what the KTM spokesman 'claimed' about their current dismissal of DI - as I noted..

& again you fail to note the importance of full throttle 'charge cooling' via the 'auxiliary' TBI.. ( & just quietly)
.. may well not be included in 'official' emissions tests, just as full boost fully enriched 4T turbos - are not..

[Pinger]

The strange thing is that they achieve to comply with the euro-4 emissions regulations according which only 0.17gr of HC (Hydrocarbons) is allowed per Kilometer, which means that only about 0.7% of the fuel is lost unburnt to the exhaust (with, say, 3.5lt/100Km fuel consumption, i.e. 2.5Kg/100Km, i.e. 25gr/Km, we have 0.17gr/25gr=0.7%).

By my rough and ready calculation, the above equates to around 500ppm as an average and Euro 5 compliance would be around 300ppm (if my calculation is correct).

Euro 4 for cars mandates a maximum UBHC of 200ppm. Will KTM use a cat' (as Aprilia has previously done?)?

The Orbital based DI as used by some (DiTech?) scooters etc - any idea what Euro# compliance they have?

[uniflow]

You know, the uniflow neatly gets around these exhaust port proximity problems, in one end out the other, With this new oil less top end I have, it should make for a clean twostroke. The only problem I see is the exhaust piston temp but I've experimented with this a little and am confident I have a solution (real world, not computer simulation). The uniflow engine that we ran in our jet boat some years ago should by rights have burnt the exhaust piston but the measures I had in place protected them (not ceramic). Ultimately this was a problem as we upped the BMEP, this new solution will curb that issue. The only other issue that has been stated many times by bystanders is the gas flow into the cylinders from the transfers, this is a non event with careful transfer angle placement, no longer having the hollow cylinder center (charge wise). My uniflow even had squish area, ran on petrol and didn't require a supercharger. My 440cc ran up to 9500 rpm, no tuned exhaust (but would be used on the next generation engine).
All this on carburetors too, not necessary to fuel inject.

[manolis]

Hello Pinger.

If in the calculations we take the CO emissions, too, then, according the euro-4 emissions regulations:
2% of the fuel can be emitted to the atmosphere unburnt (HC) or incompletely burnt (CO).

Thanks
Manolis Pattakos

[manolis]

Hello J.A.W.

You write:
“You cannot accept at 'face value' - what the KTM spokesman 'claimed' about their current dismissal of DI - as I noted..”


However, when a spokesman of a company talks about their various projects, he weighs every single word he says.

And the real issues / problems of the project it replaces, is the perfect basis for supporting a new project.



You also write:
“& again you fail to note the importance of full throttle 'charge cooling' via the 'auxiliary' TBI.. ( & just quietly)
.. may well not be included in 'official' emissions tests, just as full boost fully enriched 4T turbos - are not..”


In the case of the Rotax 850 E-TEC:



which appears as the TOP high-tech 2-stroke today,
the simple / cheap 2-stroke ended up requiring, among others:
a high-tech injector per cylinder to inject fuel directly into the combustion chamber,
a conventional injector per cylinder for “charge cooling” at full throttle (which is OK because it is not included in the “official emissions tests”, yet),
sealed crankshaft bearings, etc.



And because of its high specific power, it is also OK the significant increase of the running cost (rough calculations in previous posts) due to the lots of expensive lubricant it requires / burns (and this despite the high-cost / increased-friction sealed-crankshaft-bearings it uses, a solution that, reasonably, will soon be phased out).


What I repeatedly write and explain is that the above are not OK (unless for some "niche" applications).
They are significant issues / problems waiting for solutions.

Thanks
Manolis Pattakos

[J.A.W.]

Hi Manolis..

Re: the BRP/Ski-Doo 850, did you view the video that I posted - of it - under test?
If you do, you'll see how hard they are run - they must be built robustly - to do so, reliably..

However, they will of course run economically, at lower power settings, (where a road vehicle more typically operates).
& as for its 4T rivals - they are inevitably complex/expensive/bulky/thirsty turbo-charged machines..

As for your contention that the KTM spokesman was saying that their 2T DI was a no go.. well.. ..since it was deemed to be ready to go on sale.. ~5 years ago by BMW - in their Husqvarna machines.. ( & just before KTM bought Husky)..
..I'd certainly have to take his comments as 'marketing speak' - rather than a straightforward technical appraisal..

[manolis]

Hello all.

Today the US-PTO published the USA patent granted for the PatRoVa rotary valve.

Here is the link:

http://patft.uspto.gov/netacgi/nph-Pars ... PN/9677434

Thanks
Manolis Pattakos

[J.A.W.]

Good effort Manolis.

But - I have a couple of questions.

Does this patent also cover your rotary valve design - for use in 2T engines?
I saw no mention of its use for 2T applications in the description, so how will it be relevant - to the thread topic?

Perhaps a new thread, with a list of patented ideas for improved ICE performance - might be the proper place for it.

[manolis]

Hello J.A.W.

The PatRoVa is for 4-strokes and for 2-strokes.


The PatATi is only for 2-strokes.

Today the US Patent Office (USPTO) mailed the Issue Notice for a patent granted for the PatATi engine:



More at http://www.pattakon.com/pattakonPatAT.htm and http://www.pattakon.com/pattakonPatATeco.htm

Officially the patent is to be published July 4, 2017.

Thanks
Manolis Pattakos

[J.A.W.]

Another patent Manolis.. well done.. & best wishes with getting tangible results...

In the theme of 'tangible results, I note that Suter, after their debut debacle at the Isle of Man TT last year,
did not even enter their fuel injected 2T 4 cylinder race bike for the 2017 TT..
..the 'official' word is that they'll try again next year..

(Mind you - even mighty Honda pulled out of the 2017 TT, after some unfortunate practice incidents)..

As for F1 2T topical interest, check this pic of a Ferrari experimental effort - from the `90s..
http://www.diariomotor.com/imagenes/201 ... indros.jpg

Details of that Ferrari are scant, but the data plate indicates, "turbo" & "216 CV"(HP) from ~1.35 Ltr, so its fairly tame for a 2T..

[manolis]

Hello J.A.W.

Quote from http://www.ferrarichat.com/forum/ferrar ... ngine.html

“. . . but the most interesting picture is of a 3 Cylinder 2 Stroke Engine with twin port fuel injectors per cylinder. It also has SOHC actuated exhaust valves. It also looks to have blanking plugs in the head for direct fuel injection if needed.”





2-stroke,
supercharged (230mN/lit specific torque at peak power),
2(?) exhaust poppet valves per cylinder,
one exhaust camshaft at the top of the engine (note: it cannot be used as balance shaft, too, because it turns at the wrong direction) makes the engine taller than a 4-stroke having equal piston stroke,
peak power at “only” 5,000rpm (yet, at 5,000 rpm the big exhaust poppet valves, the camshaft and the valve springs feel as operating at around 10,000rpm in a 4-stroke).

The basic design reminds the Detroit Diesel (GM) architecture, but there, there were four exhaust poppet valves per cylinder.


If it was to run at higher revs (say 10,000rpm for 400hp/lit) then only a rotary exhaust valve could do the job.


On the other hand, without any increase of the height, the F130 of Ferrari can turn to an opposed piston (full balanced, double capacity, more than double power, higher rev limit, through scavenging, etc, etc.).


I can’t see any real innovation or real advantage in the Ferrari F130 configuration.



For instance, compare the Ferrari F130 with the Cross-Radial PatATi:



Thanks
Manolis Pattakos