2-barrels and a few more pounds (a.k.a. the new Huskies)

[Saw Man]

The loss of unburnt...and still burning fuel thru the exhaust port is referred to as "short circuiting".

The more "short circuiting" can be reduced....the more efficient combustion becomes.

Not exactly the same, but think of results like electricity. If a leak path is open, the the motor is less efficient, or can be damaged. If your holding a live wire, and a leak path goes thru the insulation thru you.....well let's just say you don't want that to happen!

Straifying, or layering a charge of clean plain air at normal atmospheric pressure seperates the incoming and out going fuel (exhaust) charges.
This seperation produces more complete combustion, cleaner...lower THC's emissions, AND saves fuel.

As Glen was describing it is done thru port timing via the piston which is really a sliding valve, or also thru reliable reed valves

Emissions can be reduced up to 70%.
Fuel savings up to 34%.
Those #'s apply to Red Max engines (since 1995), BUT the wonderful thing is any engine that is using this design like Glens, Jeff S, and Ben Walker are describing will have all those benefits.

You can literally smell the difference between a regular engine(stinky), and a Strato Charged (cleaner) engine.

I have both a VHS tape, and a laptop video disc on how it works, but I don't know how to run it on my PC, and post it.
Any help on how to do it will get it done.

 

[bwalker]

With this system, a tuned expansion chamber exhaust should be much less effective as there's so little fuel going out the exhaust port, which would normally be stuffed back into the cylinder.

Thats not really true, glens. A epxansion chmabers job is to first suck the exhaust gasses out and then ram ram air back into the chamber to raise the combustion chamber pressure above atmospheric. The motor doesnt care if the air rammed back in has un burnt fuel in it or not as long as oxygen is present. Idont see why a tuned pipe could not be made to work with one of these engines. In fact Sea Doo direct injected water craft motors have had tuned pipes for years and with their direct injection sytem there is much less HC loss than with a strato type engine.

 

[glens]

Ben,

The way I see it is the way things generally are now, raw fuel (in proper mixture with air) goes out the exhaust port and stays there as the exhaust "valve" closes.  The tuned pipe times a return pulse to push that viable mixture back into the cylinder just before the exhaust "valve" closes; thus providing more mixture than the engine of that size would unassistedly be able to trap for work.

If the material being pushed back into the cylinder at the last moment were nothing but filtered atmosphere, then more fuel could be introduced while the pipe is harmonically active than when otherwise, but that would really require a mapped fuel delivery scheme with electronics for best effect.

If the material being pushed back into the combustion chamber where inert gas, then a merely greater compression ratio (initial combustion pressure) could be achieved, but with the still lesser amount of trapped "goods" to burn.

Assuming there are just those three "black and white" possibilities; which do you think would most closely match the latest Elux scheme?

I've got an answer in mind...

Glen

 

[Saw Man]

Interesting "boom tube" dialogue.

Food for thought:

1.The E-Lux stratified (loop) design will benefit more from an expansion chamber that the Mitsubishi TLE, and the RED MAX Stratofied designs due to the long tubes that affect port timing speed, and fuel is warmer going thru the tubes.

It (loop) is less efficient, and is posing interesting engineering & manufacturing situations (aka-problems) relative to maximum speeds, and power to weight. However, it will benefit by saving emissions points allowing companies to sell more dirty engines., and keep sales volumes up.

The volume & profit is in the 22cc-50cc engine sizes. Larger engines sales volumes are substantually less, and aren't generally as profitable,

2. When I figure out how to run the video, or get some help as how to...you'll really enjoy it.
I have pictures of the fuel flow, flame wave(s) and actual tempature charts by a minature camera, and thermo couples, but it's hard to reproduce. One time I spent so much time looking at them,. my eyes crossed.

Some subject deviation for the moment, but it's on my mind. My son is getting married on Friday...and there alot top do....yet.

Emission regs are much more....alot more relaxed on larger engines...for the time being. Companies that are behind in basic R & D, and also tooling up for new regs have had four choices:

1. Four stroke develpoment-usage. Split that in two sub groups;
A. "Normal 4 stoke straight gas.
Dolmar(4 cycle chain saw), Dolmar/Makita/Fuji 25.5cc-33 cc trimmer engines) Briggs & Stratton, Honda.
Husqvarna's "new" 4 stroke is actually Honda's reskinned.

B. Hybrids 4/2. Four stroke w/ two cycle gas.
Shindiawa, and Stihl.
Shindiawa has actually go on record as stating their research has lead them to the conclusion that the future of the two cycle is basically DEAD. They're pursuing four cycles.
They actually had a joint R & D venture going with Dolmar/and Fuji but split off. They're one that's way behind.
Echo quietly did have Honda's 4 stroke for one year.

2. Buy technology, while trying to develop their own.
Stihl, Husqvarna, Jonsereds, Mitsubishi.

3. Pursue raw design development of two cycles.
Red Max (Komatsu) "Stratofied", Tanaka's "Pure Fire", Maryauma's "CE", and Echo's "Tornado" are examples of raw research.
Between them, they have so many patents, and properitarty designs....they have become the leaders.
Red Max doesn't need a catalytic muffler at all.
Echo doesn't ...yet. But it's so lean that Tornado's don't last like their older engines.
Tanaka doesn't need catalytic mufflers....yet. But will.
Maryauma doesn't need catalytic mufflers...yet. But will.

4. Get out of making some product. Lawn Boy, Tescumseh are just two.

Funny how the the 'big boys' kept saying. "It can't be done", "Technology DOESN'T exist to meet the proposed regs", and last..."It will raise prices so much....they'll go out of business".
Yet these four companies DID IT!!!
Red Max and Tanaka were Federally meeting both CARB, and EPA back as far as 1995....while the rest were crying.

We all will be better off because of the huge improvements in engines, and manufacturing.
Capitalism, and market demands are forcing better products.

 

[glens]

Originally posted by Mike Maas
Doesn't the burned gas/unburned gas mix that gets pushed back in, lack oxygen because of the burned fuel?

To the extent it does get pushed back in, it would be the "inert gas" I spoke of.  There wouldn't be much unburned fuel/air mixture going out the exhaust as a result of incomplete combustion before the port opens.  It would still burn, just like the muzzle flash on a revolver (and which action is largely responsible for the pressure wave which reflects back to re-stuff the chamber).  Unburned fuel/air mixture that goes out the exhaust port is (at least) the first stuff into the chamber via the transfer ports.  Any of that which gets pushed back in by the pressure wave reflecting off the front cone of an expansion chamber is at the proper mixture of fuel-to-air.  Some inert gas (already burned fuel/air mixture) might make it back in, too, but it wouldn't change the fuel-air mixture (ratio) any at all; it would just make the engine seem that much smaller.

In other words, the strato charged system would have fresh air pumped back in, the traditional system would be pushing burned exaust gases back in, with a small amount of raw gases.

Yes, with the "strato charged system" (such as we see in the images in this thread), the largest percentage of what would get bounced back in by the pressure wave would be filtered atmosphere, and it would cause the incoming mixture to go lean unless it had extra fuel added to account for the extra air.  Without using electronics to add that extra fuel only when "on the pipe", the mixture would become too lean unless it was too rich "off the pipe".

That's the way I envision it...

Glen

 

[bwalker]

But , what if????

What if you altered the port time #'s so the "cushion" of scavenging air is longer in duration and mass? After the chamber was emptied excess air would be present in the pipe. Then you could ram it back in via a coned pipe and viola instant power. Keep in mind the fuel mixture off course would have to be richened up and the timing figures for the pipe and ports would have to be fleshed out in sim as they would differ from what a standard engine uses.
Also keep in mind getting fuel into any spark ignition engine is not a problem its getting air in that the problem and incidently why a super charger or turbo chgarger works so good.

 

[glens]

Are you saying you think that more plain-Jane air could be worked with, with the necessary extra fuel added to compensate, than if already-proper-mix were solely used?

Using the sliding-fuel-mixture scale necessary with the air-only system would be great, but without it, when the saw went "off the pipe" it would fall on its face a ton more than it does already, don't you think?

Glen

 

[RDP]

The 455 has the same sort of two-barrel arrangement, but now has a modular engine with metal-insert-encased plastic crankcase, horizontally split.

Glen

Boy the Stihl folks should have a field day with that one at the shows.

 

[trimmmed]

Why?, does this somehow make their 290 a better saw?

 

[glens]

It already was.&nbsp; <tt>:</tt>)

But the horizontally-split case that Stihl uses is a complete metal engine bolted into the plastic chassis.&nbsp; Ultimately it isn't that big of a deal because they both work but there's something about having rotating parts fully encased in metal that seems a bit better to me.

Glen

 

[RDP]

Why?, does this somehow make their 290 a better saw?

Is there something wrong with a 290 ?

 

[sedanman]

The way Gypo has been smashing saws, maybe he should start running 029's. The saws would be no less dead than the Husky's and Dolmars he's putting to rest but it would be easier on the budget.

 

[canguy21]

So it's Last Post for the 55. It is our biggest seller and is my choice for a mid-range workhorse. Far more rugged than the 290 and can run 3/8 chain. I am sorry they are going to the horizontal split on the new 455. My 345 works well enough but does not get heavy use It is also not economical to rebuild.
Sounds like the 575xp was built by government committee.

 

[RDP]

Everyone has their own opinion on the subject, however from what I have seen there is nothing wrong with 029/290 if put in operation in its intended application. Of course some have been over worked and stressed and the same applies to the 55 series. Unless I am mistaken however you have more HP per lb with the 029/290 than with the 55's.

All things being equal, bottom line the most important is the quality and competence of your local dealer and his after sales support & service.

 

[Stumper]

One or two people had run the saw and although I'd not intended to do so myself, I couldn't stand it any longer, so donned the chaps and hearing protection (not that it's entirely necessary with this saw) and sliced a round.&nbsp; I was going to put it up when Jeff motioned for me to make another as he readied his camera.

At least my shades where Stihls.

Check out the chicks checking me out...

http://www.arboristsite.com/attachment.php?attachmentid=16594
Love those Teva chainsaw sandals!

 

[MacDaddy]

Osha

Are those work boots in the picture OSHA aproved It must be some new steel like ford made (quite steel) this must be noseeum Steel Very hard to get