Author Topic: Low noise Two stroke?  (Read 14958 times)

Offline Niels Abildgaard

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Re: Low noise Two stroke?
« Reply #30 on: November 20, 2015, 07:39:31 PM »
The Crecy was not low noise and the crankcase oil stayed golden.
This means that all piston and sleevevalve lubricant took the easy way out.
Some pollution

Offline BillTodd

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Re: Low noise Two stroke?
« Reply #31 on: November 21, 2015, 12:59:04 PM »
The Crecy was not low noise and the crankcase oil stayed golden.
This means that all piston and sleevevalve lubricant took the easy way out.
Some pollution

All true Neils, but then the crecy was for military use and they just didn't care   :shrug:

Just thinking , given that you are trying to design a relatively low performance, quiet and clean two stroke (i.e. something ideal for portable generators etc.).  How about a stepped piston (twin) design, so you can separate the crankcase oil ?

Your poppet valve and cam might need some pretty good lubrication, which would be potentially smokey if in a petroil mix.

Offline Niels Abildgaard

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Re: Low noise Two stroke?
« Reply #32 on: July 24, 2022, 01:42:25 PM »
Please find the papers from a two stroke lovers get together 2020

https://drive.google.com/drive/folders/1YNYWcnGSqsfYqu_EV1XM_g0HQ9pOxbmv

Offline Niels Abildgaard

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Re: Low noise Two stroke?
« Reply #33 on: June 19, 2023, 04:24:21 PM »
Until some prior art can be found I feel very proud as spiritual father of this:

https://www.fvt.at/ka/en/references/layout-and-design-of-an-innovative-range-extender-engine.html

My first written describtion is this I seem to remember

https://www.homemodelenginemachinist.com/threads/sidevalve-single.23909/#post-258381

If You know of some prior art please let me know as roof/ceeling here in house is getting uncomfortably low.
« Last Edit: June 19, 2023, 04:31:29 PM by Niels Abildgaard »

Offline Niels Abildgaard

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Re: Low noise Two stroke?
« Reply #34 on: June 29, 2023, 07:34:14 PM »
The austrians from the above link are working to dominate future EV car range extenders.

They have claimed more than once that crankcase charging will not allow a three-way catalyst so they do it the Detroit diesel way.

Is it true?
By crankcase scavenging with air only and total loss lubrication about 1% of fuel amount it hard to imagine that catalyst cannot burn that?

https://drive.google.com/drive/folders/1YNYWcnGSqsfYqu_EV1XM_g0HQ9pOxbmv

Kirchberger Graz
« Last Edit: June 30, 2023, 08:36:46 AM by Niels Abildgaard »

Offline Admiral_dk

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Re: Low noise Two stroke?
« Reply #35 on: June 29, 2023, 09:15:20 PM »
Hi Niels

I might be reading this wrong - but beside a kind of Fuel / Range Extender - nothing much has come from all these studies, that will see us having a Two-Stroke in our next wheehicle ....

I have ambivalent relationship to Two-Strokes, as I loved to ride them in my youth, but also tired of all the extra maintenance / lower reliability, compared to Four-Strokes ....

Mvh   Per          :cheers:

Offline AlexS

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Re: Low noise Two stroke?
« Reply #36 on: July 11, 2023, 10:58:17 AM »
Interesting documents you shared.

Ah if used as range extender for fixed rpm and load it might work out. And as UNIMORE showed a separated oiling system. And ad Kirchberger showed a Uniflow exhaust valve setup.
Only maybe have to test it with trying to use hydrogen or a blend for combustion this should give a weight/power output. I know you can generate electricity form hydrogen fuel cells. But there you have to condition the PEM cells and require (as far as I know) platina or similar resources (availability?).
So as second option?

Offline Niels Abildgaard

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Re: Low noise Two stroke?
« Reply #37 on: July 11, 2023, 01:14:50 PM »
Interesting documents you shared.

Ah if used as range extender for fixed rpm and load it might work out. And as UNIMORE showed a separated oiling system. And ad Kirchberger showed a Uniflow exhaust valve setup.
Only maybe have to test it with trying to use hydrogen or a blend for combustion this should give a weight/power output. I know you can generate electricity form hydrogen fuel cells. But there you have to condition the PEM cells and require (as far as I know) platina or similar resources (availability?).
So as second option?

I think it is the real solution and my question is if the charge free crankcase is nessecary for going threeway catalysing.
The main road is to keep charge low(MEP =6bar), and uniflow.In that case a V2 with common crankcase
will be much simpler and lower mass.
Click on the picture and open in another window
It shows a comparison of a crankcase scavenged 100/150 mm bore/stroke cylinder with a blower fed doing same work



« Last Edit: August 08, 2023, 04:54:03 PM by Niels Abildgaard »

 

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