How does anyone know it is HCCI combustion in the Ryger engine? That is what is it about the engine that makes anyone conclusively conclude it is HCCI? The people I have read about working on HCCI seem to have lots of $$$$$$$ and instrumentation up to the ying yang so they can even play with it.
There are some bigger 2 stroke race engines that win races and once they are going for a bit the spark plug is not needed, that is shutting off the ignition at full throttle won't do anything but no one is indicating it to be HCCI.
HCCI is what makes the Ryger so different, and being able to do what it does. The puzzle is coming together.
HCCI is the only way to have power and economy . It will be tied up with the air fuel waiting out 1 cycle before it gets to the
transfer passages. I believe this is the control and gives the fuel air time to get it stuff sorted out.
Neil
I think I have seen HCCI in action. In karts, which were all once direct drive (no clutch), sometime a guy might spin, crash or whatever and the chain breaks. Even if the throttle may be shut, the engine revs to infinity (at least 30,001 rpm). Then the man gets out and pulls the spark plug cap off and it keeps running and we're up to 30,002 now. He then, after recovering from the HV Taser electric shock, covers the inlet tubes to the airbox. Then the engine will slow and stop. Certainly a light load, high rpm and lean condition which HCCI (ATAC ?) seems to like.
HCCI is what makes the Ryger so different, and being able to do what it does. The puzzle is coming together.
HCCI is the only way to have power and economy . It will be tied up with the air fuel waiting out 1 cycle before it gets to the
transfer passages. I believe this is the control and gives the fuel air time to get it stuff sorted out.
Neil
HCCI would make any engine different but how does anyone know it is HCCI happening? Air fuel waiting out 1 cycle or more happens in lots of engines and lots if not almost all engines have exhaust contamination of the air fuel, some a small amount and some a large amount and the rest somewhere in between. I would think that HCCI doesnt happen by time and chance but has to be forced to happen and then more greatly forced to be kept under control and it seems documented literature would agree.
If the Ryger engine has solved the HCCI riddle then that is a bigger achievement than a clean 2 stroke or a 70 HP 125.
Maybe Wobbly or Frits may know the answer to this. ...
Curious if any of the V4 500cc 2 strokes ever tried 2 into 1 pipes? Would have improved bottom end and midrange with very minimal peak loss. Plus the sound a 2 into 1 makes... incredible!
How does anyone know it is HCCI combustion in the Ryger engine? That is what is it about the engine that makes anyone conclusively conclude it is HCCI? The people I have read about working on HCCI seem to have lots of $$$$$$$ and instrumentation up to the ying yang so they can even play with it.
There are some bigger 2 stroke race engines that win races and once they are going for a bit the spark plug is not needed, that is shutting off the ignition at full throttle won't do anything but no one is indicating it to be HCCI.
Absolutely. Besides that, HCCI needs "quite a bit" of EGR inside the combustion chamber to work. This produces residues on the piston, combustion chamber etc. even with no oil in the mixture. But the piston which had been shown to us was clean, instead.
Some say that 4 strokes are a hassle cos they need regular oil changes and that the environment can be damaged due to the incorrect disposal of the used oil. This one's done 200k km and, as you can see, all that is a non issue. You just have to question everything these days.
[QUOTE=Haufen;1130924492]Absolutely. Besides that, HCCI needs "quite a bit" of EGR inside the combustion chamber to work. This produces residues on the piston, combustion chamber etc. even with no oil in the mixture. But the piston which had been shown to us was clean, instead.[/QUOTE
Absolutely. Besides that, HCCI needs "quite a bit" of EGR inside the combustion chamber to work. This produces residues on the piston, combustion chamber etc. even with no oil in the mixture. But the piston which had been shown to us was clean, instead.
From what I am understanding of HCCI so far is, EGR were used in early trials to raise the temp for ignition to occur. More recently others have been trialing other ways of raising the temp, so EGR does not need to be used. Maybe the high primary pressure is enough to mechanically do this, so very little or no intentional EGR is required for the Ryger. This will also keep it simple.
Neil
Absolutely. Besides that, HCCI needs "quite a bit" of EGR inside the combustion chamber to work. This produces residues on the piston, combustion chamber etc. even with no oil in the mixture. But the piston which had been shown to us was clean, instead.
Curious if any of the V4 500cc 2 strokes ever tried 2 into 1 pipes? Would have improved bottom end and midrange with very minimal peak loss. Plus the sound a 2 into 1 makes... incredible! I built one for my RZ350 back in the day.
I don't know of any 500 cc V-fours; I do know, as no doubt you do too, of the König boxer-4. The sound was, as you say, heavenly. The power was... well, it made hardly any more power than a good 250-twin of the same era: 75 hp on petrol .
I think I have seen HCCI in action. In karts, which were all once direct drive (no clutch), sometime a guy might spin, crash or whatever and the chain breaks. Even if the throttle may be shut, the engine revs to infinity (at least 30,001 rpm). Then the man gets out and pulls the spark plug cap off and it keeps running and we're up to 30,002 now. He then, after recovering from the HV Taser electric shock, covers the inlet tubes to the airbox. Then the engine will slow and stop. Certainly a light load, high rpm and lean condition which HCCI (ATAC ?) seems to like.
I've seen that too firsthand several times but its different conditions than WOT conditions. If the throttle on the runaway engine is opened up and then the spark plug wire is removed the engine will quit unless it has a hotspot like an overheated plug to keep it going.
i downloaded pdf at the bottom of page of above site, also clicked on next chapter.. no problems.
Thanks for the links. So they achieved HCCI combustion up to 16 bar BMEP on a 4-stroke engine charged to 3bar absolute pressure.
So that would be 8 bar BMEP on a two-stroke engine firing every revolution and charged to 3bar absolute pressure.
With an exhaust pipe only, maximum charging is at about 1,5 bar, so that would be 4 bar BMEP.
From there on, it would be quite a way to go to the claimed 16 bar BMEP for the Ryger at full load. And the guys from the paper had most likely more equipment and instrumentation at their disposal than Harry and his supporters (which is not always necessary, but it does make life easier if you have it, for sure). So I stand by my point. Full load HCCI on the Ryger? Highly unlikely.
(Don't get me wrong, I would love to be proven wrong and then to learn and understand new things two-stroke and then to use them myself. But until that, I am a facts kind of guy, and at the moment I do not know any facts that would lead me to a different conclusion.)
No V4 GP engines ran 2:1 but from my experience with World Champ Ski engines the 2:1 doesn't even come close to well designed
single pipes, no matter where you bring the headers together.
You can get a big boost in top end power by cutting the piston skirts short on the Ex side.
This creates havoc with the jetting, but once sorted it does work well.
I spent a huge amount of time on EngMod trying to replicate or even get close to twin single pipe performance on a hot road RZ350, but simply
couldn't achieve the mid, or top end, with a 2:1.
In twin snowmobiles and those adapted for small aircraft use, the best performance is achieved with a 2:1 when the Ex duration is up at 200*.
But this then seriously affects the powerband shape,as it looses a huge amount of mid power that then needs the pipe designed to get some of it back,badly compromising
the top end - just not worth it IMHO.
Edit - here is about as good as it gets, a very good aftermarket 2:1 Vs aftermarket singles.
Ive got a thing thats unique and new.To prove it I'll have the last laugh on you.Cause instead of one head I got two.And you know two heads are better than one.
The first big use of 2-into-1 pipes in outboarding began with alky-burning inline twin and four-cylinder Mercurys using open megaphones in the late-'50s. Makers and users of these single pipes said they had better acceleration. (EDIT--I say this not to argue the point with Wayne, but just reporting what I recall others saying at the time). Another advantage was a reduction in weight, outboards already being top-heavy, which made for a little better handling and cornering. This weight reduction became a greater factor with the advent of expansion chambers, particularly slider-pipes, in the mid-late-'60s, since the pipes and support brackets and slider mechanisms all were heavy. But by the late-'70s, many of the top racers were using one pipe per cylinder anyway. Outboards run the whole heat at WOT or nearly so, and peak horsepower may be more relatively important than it is for motorcycle roadracers who have lots of slow corners and tire traction issues.
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