Inside the MS362

[Philbert]

I emailed Husky and Stihl for an explaination on strato design. Husky was the first to get back to me with this video. Very interesting! This engine is on the Husky 455/460.

The file that bitzercreek sent me is 12MB - the A.S. size limit for .avi files is 300KB, so it is about 40X too big to post.

I posted it on YouTube (my first!):

Strato Animation 460 XTORQ
http://www.youtube.com/watch?v=IY7zQKw4qsQ
If you like it, please send rep to bitzercreek as he found it.

Philbert


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[Freehand]

Nice post Philbert,awesome animation...Props to Bitzercreek as well....opcorn:

 

[bitzer]

The file that bitzercreek sent me is 12MB - the A.S. size limit for .avi files is 300KB, so it is about 40X too big to post.

I posted it on YouTube (my first!):

Strato Animation 460 XTORQ
http://www.youtube.com/watch?v=IY7zQKw4qsQ
If you like it, please send rep to bitzercreek as he found it.

Philbert

Thanks for getting it out there Philbert! It's not the same as the 362, but I think its a good representation of how the strato works. I did not expect the strato air to go down the transfers. Thanks again!

 

[Wild Knight]

I've always heard that once the major bottleneck is removed, rule of thumb is that changes to ports and transfers henceforth should be made proportional to each other. How far you widen the exhaust should be proportional (not necessarily 1:1) to how far you open the intake, or overall flow through the 'air pump' is disrupted. Since the bottleneck of the intake port could not be alleviated, how does widening the exhaust so much affect this rule of thumb?

Do you think overall flow can be increased by forcing a greater strato charge?

 

[blsnelling]

Do you think overall flow can be increased by forcing a greater strato charge?

I'm hesitant to do that since there's no fuel with it.

 

[bitzer]

I don't really see how more flow could be induced by a greater strato charge. I would think less strato charge if anything. More fuel, faster to where it needs to be.

 

[Erick]

I've always heard that once the major bottleneck is removed, rule of thumb is that changes to ports and transfers henceforth should be made proportional to each other. How far you widen the exhaust should be proportional (not necessarily 1:1) to how far you open the intake, or overall flow through the 'air pump' is disrupted. Since the bottleneck of the intake port could not be alleviated, how does widening the exhaust so much affect this rule of thumb?

Do you think overall flow can be increased by forcing a greater strato charge?

I'm hesitant to do that since there's no fuel with it.

Brad, as you well know I'm more of a "teach a man to fish" kinda guy... so with said.... stop and think about all you have learned in this thread.

What are you trying to accomplish by porting a saw to begin with???

What is the optimal fuel to air ratio???

What happens when you disable the strato linkage???

So then why is the mixture right when the strato ports are working?

Where does the extra air come from to lean out the mixture to the optimal level???

Why should the tiny (by standard two stroke measures) intake port be a bottleneck???

Why does your saw not turn as many RPMs???

Where do the RPMS come from when you do a standard two stroke???

:dunno:


Like I said before you're getting better at this and the reason for that is you are starting to figure out why you do what you do and what effect it has when you do it...... Think about what you're doing here.


BTW nice job... took some nuts to just throw it out there like that unsure of the result.... on someone else’s saw even NUTS.

 

[gonecountry]

Wild idea proably won't work

This is just an idea and there maybe a problem with it that someone will have to point out but here it goes.

What if your were to widen the intake port some? Yes it would allow the mixture charge to go into the strato cavites and then on out through the exhaust but thats no different than a conventional two-stroke. But when the piston is at TDC and the mixture is flowing into the crank case it would have a wider port to flow through.

Is there any reason that the fuel mix going into those cavaites would actually cause any harm?

Thanks Jon

 

[bitzer]

This is just an idea and there maybe a problem with it that someone will have to point out but here it goes.

What if your were to widen the intake port some? Yes it would allow the mixture charge to go into the strato cavites and then on out through the exhaust but thats no different than a conventional two-stroke. But when the piston is at TDC and the mixture is flowing into the crank case it would have a wider port to flow through.

Is there any reason that the fuel mix going into those cavaites would actually cause any harm?

Thanks Jon

The problem I can see with that is that the intake would never close as it would never be sealed by the intake skirt.

 

[blsnelling]

Brad, as you well know I'm more of a "teach a man to fish" kinda guy... so with said.... stop and think about all you have learned in this thread.

What are you trying to accomplish by porting a saw to begin with???

What is the optimal fuel to air ratio???

What happens when you disable the strato linkage???

So then why is the mixture right when the strato ports are working?

Where does the extra air come from to lean out the mixture to the optimal level???

Why should the tiny (by standard two stroke measures) intake port be a bottleneck???

Why does your saw not turn as many RPMs???

Where do the RPMS come from when you do a standard two stroke???

:dunno:


Like I said before you're getting better at this and the reason for that is you are starting to figure out why you do what you do and what effect it has when you do it...... Think about what you're doing here.


BTW nice job... took some nuts to just throw it out there like that unsure of the result.... on someone else’s saw even NUTS.

I think what you're saying is...go ahead and let those strato ports flow. Open then up and let the extra fresh air mix with the overly rich fuel charge. Ehhh? So what do you want? 25%-30% gains?

 

[Andyshine77]

How do strato engines work?

Well the clean air/strato ports create an air buffer, they fill the cylinder with a puff of clean air.

Remember standard piston ported 2cycle engines run very inefficiently. During each cycle a small, but measurable percentage of raw air/fuel mix is expelled out of the cylinder before the piston can fully seal off the exhaust port. Because a strato engine shoots a bit of clean air into the cylinder, before the fuel enters the cylinder, the expelled material is now simply air.

 

[Andyshine77]

The file that bitzercreek sent me is 12MB - the A.S. size limit for .avi files is 300KB, so it is about 40X too big to post.

I posted it on YouTube (my first!):

Strato Animation 460 XTORQ
http://www.youtube.com/watch?v=IY7zQKw4qsQ
If you like it, please send rep to bitzercreek as he found it.

Philbert


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I guess I'm a little late.

 

[gonecountry]

The problem I can see with that is that the intake would never close as it would never be sealed by the intake skirt.

I did think of that but then I thought.. So?

Proably a reason it should be I suppose.

 

[Erick]

I think what you're saying is...go ahead and let those strato ports flow. Open then up and let the extra fresh air mix with the overly rich fuel charge. Ehhh? So what do you want? 25%-30% gains?

Balance Daniel-san.

Go SLOW, it's to hard to put it back..... grind a little, test a LOT!

 

[bitzer]

I think what you're saying is...go ahead and let those strato ports flow. Open then up and let the extra fresh air mix with the overly rich fuel charge. Ehhh? So what do you want? 25%-30% gains?

Brad I think your gains are pretty awesome on this saw as it is, but only further experimentation would tell I guess. The way I'm thinking is that the strato air creates a buffer and it fills in space or a volume of area. That is why there are no increased rpms at WOT because it still takes that long to push that extra air out even with increased mix flow. The strato air is taking up the same amount of space and with more air it might take up more space. I know that some of the strato air mixes with fuel, it would have too, but not all of it does, hence the sweep of the exhaust. I guess without trying one would never know tho.

 

[bitzer]

I did think of that but then I thought.. So?

Proably a reason it should be I suppose.

I think you would lose velocity and impulse.

 

[Andyshine77]

You can see that the pocket in the piston doesn't actually "carry" the fresh air charge. I simply creates a passage way for the fresh air to get into the the transfers, ahead of the fuel charge. That way fresh air is being used to purge the exhaust, rather than fuel mix.

Exactly what I was trying to say, I haven't read the whole thread yet.

 

[breymeyerfam]

my question: what would happen if I would install a standard style piston, and manufactured an intake adapter plate that blocks off the strato port. then installed a standard boot and carb... oh and dont forget to widen the intake to 70%!

 

[Andyshine77]

I think the easy way would be to draw fuel into the strato ports. How to do this I'm not sure.:dunno:

BTW this is a really good thread for the most part.

 

[gink595]

my question: what would happen if I would install a standard style piston, and manufactured an intake adapter plate that blocks off the strato port. then installed a standard boot and carb... oh and dont forget to widen the intake to 70%!

Thats easy... A 361