ESE's works engine tuner

[speedpro]

but it is good to know it can be done easily and i ...

Yeah that is real easy. I was looking at a similar problem and decided on the whole chassis, suspension, and wheels. Much much easier.

[sonic_v]

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When I was around at the team ESE workshop yesterday I had the great fortune of meeting Thomas. We got talking about small 2-Strokes and drive-ability.

He showed me a RGV250 cylinder and pointed out the black oily gunk in the transfer ports. This gunk was high up in the port where the port exits into the cylinder. It was obvious that at some point in the rev-range there was blowback happening when the transfers opened.

Thomas pointed out that if this blowback could be stopped it would greatly widen the power band of the motor. He then drew some pictures of how it might be done using Fluid Diodes and told me that a Scroll Diode would probably be more effective in the transfers on a 2-Stroke than a Vortex Diode.

He said that in steady flow conditions the Vortex Diode looks like it would work better in the inlet but in a 2-Strokes unsteady flow the Scroll Diode has proven best. And that at high RPM the Scroll Diode is more effective than a reed valve. Looking at the pictures it all made sense.

The Team graciously gave me the OK to post these ideas and said they are looking into using it themselves and Fluid Diodes have been run experimentally in 2-Strokes. Where they showed no extra power but no loss of power either and a lot of real promise for widening the existing power band.

So here's a first for Buckets, to my knowledge anyway, the idea of using Fluid Diodes in the transfers and inlet to reduce blowback and thereby broaden the power band.

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some research carried out in Israel.

http://www.sae.org/technical/papers/830092

[Skunk]

1971 paper on Scroll diodes in two stroke engines...

[bucketracer]

Some Pic's of how scroll diodes work and how they could be used in a 2-stroke.

Pic-1 shows the key dimensions. The 30 inlet angle is important as is the r=2h.

Pic-2 shows how they work and where they could be fitted to a 2-stroke engine.

Abstract: from Sonic-v link

The typical convex torque of a simple two-stroke engine having a port-controlled piston is attributed to the backflow through the scavenge ports. It is proposed here to suppress the backflow by installing scroll diodes at the scavenge ports. Experimental observations on a fired engine demonstrate the remarkable improvement achieved with the diodes installed.

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[F5 Dave]

That is interesting but anecdotaly that would have to have some effect on the flow in the same way that suzuki's old 1/2 case reed induction did on intake.

The difference between fluid & gas is that fluid is largely incompressible & gas is easily compressed. It would stand to reason that this would affect the std model as might the expected pressures designed for.

However an open mind, always experiment. know some crowd experimenting with rifled transfers. Didn't become the next big thing as far as I'm aware.

[TZ350]

Fluid Mechanics/Dynamics deals with the flow of liquids and gases.

The way a Fluidic Diode works is that in the forward direction the Fluid (gas) flows directly in a laminar manner from the inlet to the outlet but in the reverse direction Fluid enters the outlet and flows directly into a area of larger volume. A larger volume means reduced pressure and gas at a reduced pressure has more resistance to flowing back around the bend. Its no longer laminar and breaks up choking the entrance to the inlet. Like the sonic waves in the exhaust this can all happen at very high speed.

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[Skunk]

The experiments with a two stroke are in the paper I put a link to. Page two has a graph of torque curves. I could get at the paper sonic_v linked to; got to pay a fee?

[Yow Ling]

I think you will find SS90 was going to mention the fluid diodes in post 820

[TZ350]

The experiments with a two stroke are in the paper I put a link to. Page two has a graph of torque curves. I could get at the paper sonic_v linked to; got to pay a fee?

Hi Skunk I could not open you're PDF document, something about Acrobat being unable to decript??

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[Skunk]

Try this one.

[TZ350]

Try this one.

No... it dos'nt work for me either. Does it for you??? could my reader be the problem??

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[Pumba]

Worked fine for me

[TZ350]

Worked fine for me

Ok.....problem my end then....thats not unusual......just ask the missus..

[craisin]

worrks fine on Ubuntu haaad tto click on view and then zoom in twice for my old eyes to reaad it

[craisin]

hey TZ my bought new from the warehouse 6years ago Dell cant open that file of skunks.
Ubuntu on the other hand is free and dual booting with XP is not a good ideA in the long run
Intels seem easier to manage with Ubuntu onboard sound is less problems.

I am different than a lot of linux freaks as its best to have a windows machine too

Trying to rux windows programs on ubuntu is a waste of time