Inside the MS362

[blsnelling]

http://www.poweruplawncare.com.au/zenoah/strato_charged.html

As quoted from Zenoah's website. BTW, Redmax uses Zenoah engines.

Zenoah is the first company in the world to achieve extremely low emission two-cycle engines. They have named this engine the Strato-Charged™ engine. 2-cycle engines have a simple structure, and are light and compact. However, due to their structure, about 30% of the mixture gas is not burned (unburned mixture gas) and is discharged as emission gas. There are various barriers that hamper the attainment of reduced emission for 2-cycle engines including a weight increase, larger engines and reduced ease of maintenance.

By employing a revolutionary engine air intake and scavenging system, this engine makes it possible to greatly reduce the unburned mixture gas. At the same time, it also has the effect of reducing emission gas to give cleaner exhaust.
Fresh air, which flows into the cylinder from the innovative air inlet port, expels the burnt gas so the mixture gas isn't depleted and is used effectively for the next combustion cycle. The newly designed combustion chamber and spark plug positioning ensure highly stable combustion without miss-firing and clean exhaust at 1/3 of the previous level. This new engine is named "Strato-charged™ engine" after the Zenoah original stratified scavenging engine without a catalytic converter.

Features of Innovative Zenoah StratoCharged™ engine are:
Low emission
Low fuel consumption
Low noise
Low exhaust gas odor and
High power comparing to our current models of the same displacement.

 

[gink595]

So what did you do with the muffler, or did miss that part? are those cats on the 362's??

 

[blsnelling]

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.

 

[parrisw]

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.

Very good design I say, clever whoever thought of it. I can't see how it would hinder performance.

 

[blsnelling]

So what did you do with the muffler, or did miss that part? are those cats on the 362's??

Sorry, but I failed to get any pics of the modded muffler. The muffler is made of extremely hard stainless steel. It's much harder to drill and grind than any muffler I've seen before. There is no cat. There is no cage. The muffler is hollow, with the exception of a pipe. The pipe has holes in it, which then exits the side of the muffler. The pipe can be accessed from the mounting flange opening. I cut the pipe fully open. I also added a Husky deflector to the left side, as when holding the saw. I made the hole the full size of the deflector and used a spark arrestor screen, which reduces the area somewhat.

 

[Philbert]

OK, in simple words, which part of the 2-cycle process is the 'scavenging system'? Is this just the fresh air/fuel mixture helping to flush the exhaust out?

Thanks.

Philbert

 

[blsnelling]

Very good design I say, clever whoever thought of it. I can't see how it would hinder performance.

The only thing hindering performance is the tiny intake port. The fuel charge still comes through this port in its entirety. It can't be made any wider because of the strato cavities in the sides of the piston. And even if you could widen the port significantly, the carb and intake tract are small as well.

 

[Maldeney]

Very Interesting for sure!

 

[parrisw]

The only thing hindering performance is the tiny intake port. The fuel charge still comes through this port in its entirety. It can't be made any wider because of the strato cavities in the sides of the piston.

Yes, but I'm sure a saw could be designed with that in mind. I was talking Strato in general, not just the 362.

 

[blsnelling]

Yes, but I'm sure a saw could be designed with that in mind. I was talking Strato in general, not just the 362.

I would have to agree with you then. They would just have to position the strato ports, and corresponding piston cavities such to allow more intake.

But now I'll play devils advocate with myself. Since fresh air is being used to purge the exhaust from the cylinder, perhaps less fuel mix is needed to fill the combustion chamber with the same amount of charge.

 

[Tzed250]

I would have to agree with you then. They would just have to position the strato ports, and corresponding piston cavities such to allow more intake.

But now I'll play devils advocate with myself. Since fresh air is being used to purge the exhaust from the cylinder, perhaps less fuel mix is needed to fill the combustion chamber with the same amount of charge.

Have you calculated the area of the main intake+strat intake and compared that to a 361?

A two-stroke has to have the correct stoichiometric ratio no matter what. The 361 would need more fuel, because it looses some out the exhaust. The 362 only looses air.


.

 

[blsnelling]

No I have not. I'll leave that to our mathematician, Timberwolf,lol

 

[constantine]

Your first intent was the right one. No saw runs in a vacuum. All facts are related. The 441 and 576 will be directly compared to the 440 and 372.

Of course it matters what the gains are, but across the field comparisons are inevitable.
.

OK, so now I'm really interested. Has anyone done a porting job on a 441? Thinking of getting an aftermarket cylinder and practicing on it. Bailey's has the OEM part for $350 - which is more that I want to spend on a "practice" piece. Are there aftermarket cylinders available for the MS 441?

 

[Curlycherry1]

http://www.poweruplawncare.com.au/zenoah/strato_charged.html

you are welcome

Looks like Zenoah patented the original design:
http://www.google.com/patents/about?id=G3sHAAAAEBAJ&dq=Zenoah

Then Stihl seems to have come out with a blizzard of patents soon thereafter with the same design (they even use the same drawings) and some modifications so that manufacturing could be done efficiently. I wonder if Zenoah sold the basic design or if Stihl raided the idea? Not sure but it does look like Stihl seems to be patenting all the latest modifications. They cite the Zenoah patent a lot and a citation search of the Zenoah patent dumps right into the Stihl patents.

 

[stipes]

Bard,,gonna ask somthing stupid to ya...

The only thing hindering performance is the tiny intake port. The fuel charge still comes through this port in its entirety. It can't be made any wider because of the strato cavities in the sides of the piston. And even if you could widen the port significantly, the carb and intake tract are small as well.

There anyway a person can trow the carb on a mill or jig bore and open it up some??? Would that help ???

 

[bitzer]

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. I can't get the vid on here. It was sent to my email as an attachment. Anyone know how I could get it on here?

 

[Tzed250]

.


See the Stihl video here.


.

 

[shwinecat]

Brad could you clarify. You had 26% at the smaller wood and 18% on the larger wood. This gave me the impression it did not have as much torque when the bar was buried. If I understood you correctly you indicated this was due to the IYO to a smaller intake. Stihlboy got me confused by larger gain in larger wood. I was thinking the opposite.

Awesome thread!!!! If I have to pay for what I have learned in this thread with beer you are going to be an alcoholic. I am sure Fatguy can help with the beer part of it.

Thanks, Brad

 

[ShoerFast]

Well of course, you like Bach, because you are always trying to get your engines in tune . . .

(sorry - I'll stop with that one)

Philbert

hey genious! click on the link i posted

As quoted from Zenoah's website. BTW, Redmax uses Zenoah engines.

Zenoah is the first company in the world to achieve extremely low emission two-cycle engines. They have named this engine the Strato-Charged™ engine. 2-cycle engines have a simple structure, and are light and compact. However, due to their structure, about 30% of the mixture gas is not burned (unburned mixture gas) and is discharged as emission gas. There are various barriers that hamper the attainment of reduced emission for 2-cycle engines including a weight increase, larger engines and reduced ease of maintenance.

By employing a revolutionary engine air intake and scavenging system, this engine makes it possible to greatly reduce the unburned mixture gas. At the same time, it also has the effect of reducing emission gas to give cleaner exhaust.
Fresh air, which flows into the cylinder from the innovative air inlet port, expels the burnt gas so the mixture gas isn't depleted and is used effectively for the next combustion cycle. The newly designed combustion chamber and spark plug positioning ensure highly stable combustion without miss-firing and clean exhaust at 1/3 of the previous level. This new engine is named "Strato-charged™ engine" after the Zenoah original stratified scavenging engine without a catalytic converter.

Features of Innovative Zenoah StratoCharged™ engine are:
Low emission
Low fuel consumption
Low noise
Low exhaust gas odor and
High power comparing to our current models of the same displacement.

+1 Gotcha

+1 Gotcha

+1 Gotcha

Glad to hear that the Strato port is not there for looks, that it has a real function, but fallowing the thread, I like my 361 even more now that it has competition!

Thanks Brad

 

[blsnelling]

Brad could you clarify. You had 26% at the smaller wood and 18% on the larger wood. This gave me the impression it did not have as much torque when the bar was buried. If I understood you correctly you indicated this was due to the IYO to a smaller intake. Stihlboy got me confused by larger gain in larger wood. I was thinking the opposite.

Awesome thread!!!! If I have to pay for what I have learned in this thread with beer you are going to be an alcoholic. I am sure Fatguy can help with the beer part of it.

Thanks, Brad

You are correct. Fred had it backwards. It would appear to me that the strato design is not feeding as much fuel under max load. The 361 and 362 were neck and neck in the smaller wood. Once you bury the bars, you can lean on the 361 significantly harder. I'm still very pleased with an 18% gain with the bar buried. Remember, this the technology that everyone's been afraid of for the last how many years, saying that it wouldn't take to mods well. I say we've proven that wrong. Slingr did a 441 and got good gains as well. I did one of the little Ryobi 10532 (Redmax GZ400), which is a strato, and it flat hauls.