ESE's works engine tuner

[Niels Abildgaard]

The 30K straight came from the horse ass I mean mouth...

I had not seen that for hatesmokescreen

[Frits Overmars]

https://research.chalmers.se/publica...4_Fulltext.pdf

A very pleasant read . Thank you Dr Lennarth Zander.

[lohring]

Compounding two strokes has been studied for a long time and is still used today. My favorite examples are the Rolls Royce Crecy and the Napier Nomad. Modern examples are container ship diesel two strokes and snow mobile engines. The best modern change is the development of the electric motor/generator coupled with the turbocharger. This allows startup and low rpm scavenging without a mechanical blower. If you add a battery pack you can store excess power from the turbine as well as regenerative braking from a hybrid drive system. This is the Formula 1 system. I believe Garrett is exploring this application though with four stroke engines. It would be a perfect combination with the Achetes opposed two stroke.

I happen to have a motor generator. I'm not sure exactly what it is and it would need an electronic controller to work. If anyone has a use for it I would glad to give it to you for the shipping cost.



Lohring Miller

[wobbly]

Frits , you are always strangely silent when anything Ryger is mentioned , yes I know a NDA was in place , but I believe you actually drove a kart with the engine on board.
My tin foil hat is crinkling as I write this.

[husaberg]

Als je niets aardigs te zeggen hebt, zeg dan helemaal niets

[wobbly]

TZ250 - 3XV Toroid with 10mm plug - 56 Bore
TZ400 - Toroid with 14mm plug - 66 Bore
Both 50% SAR.

[Haufen]

Looks like there may be some performance to be found in our good old two-strokes after all - even if the baseline is a certain "125cm³ motorbike racing engine from Aprilia"

Basis
A 125 cm³ motorbike racing engine from Aprilia is used as the basis for the simulations...

Abstract
The use of MAN-type loop scavenging port arrangements in a 125 cc two-stroke racing engi-ne is being investigated. These make it possible to provide larger cross-sections for the trans-fer ports, but at the expense of the exhaust port cross-section. The investigation is carried out using 1D calculations with GT-Suite. It is shown that significantly higher maximum outputs are possible in this way. However, this requires large exhaust widths, as otherwise the exhaust port is too small and the advantage of the larger transfer cross-section is overcompensated. Mixed forms between the original MAN loop scavenging and Schnürle loop scavenging can represent a good compromise. One open point is the quality of the scavenging. A study found in the literature on the use of MAN loop scavenging on a small engine shows significantly worse results than is known from large engines. There is still a need for further investigation here.

Conclusions
It has been shown that port arrangements of the MAN loop scavenging type have the potential to achieve higher peak outputs than is possible with conventional configurations. A configuration with the same maximum output as the basis but a wider power band is also shown...

You can access and download the paper here:
https://mobilityrxiv.sae.org/preprin...--sae-pp-00395

[yatasaki]

Haufen, I would say that we have loop scavenging if there is transfer port beneath exhaust port on existing cylinders we use today. ..short circuiting comes on my mind immediately .
Loop was abandoned on diesels because of scavenge efficiency, especially when long strokes were introduced.
Uniflow is unbeatable.

[porttiming124]

TZ250 - 3XV Toroid with 10mm plug - 56 Bore
TZ400 - Toroid with 14mm plug - 66 Bore
Both 50% SAR.

Woobly
Can you tell me if there is an ideal thickness of the aluminum between the bowl and the exterior?

[Frits Overmars]

Looks like there may be some performance to be found in our good old two-strokes after all.... You can access and download the paper here:
https://mobilityrxiv.sae.org/preprin...--sae-pp-00395

This 'Novel Port Design' looks strangely familiar

[wobbly]

Porttiming 124 - the combustion bowl thickness depends entirely upon how much support the cover can provide.
You can regard the bowl inner face as a cantilevered beam , clamped at the bore and with a uniformly distributed load across it from the peak cylinder pressure.
In the 3XV design I ended up with 7mm thickness , as the cover , when the assembly was analyzed in FEA equalized the stress level across the bowl by its added support around the plug sealing face.
Without sufficient cover support the 6061 insert would come close to the the yield point of the material.

[porttiming124]

Porttiming 124 - the combustion bowl thickness depends entirely upon how much support the cover can provide.
You can regard the bowl inner face as a cantilevered beam , clamped at the bore and with a uniformly distributed load across it from the peak cylinder pressure.
In the 3XV design I ended up with 7mm thickness , as the cover , when the assembly was analyzed in FEA equalized the stress level across the bowl by its added support around the plug sealing face.
Without sufficient cover support the 6061 insert would come close the the yield point of the material.

Perfect thank you

[Flettner]

Haufen, I would say that we have loop scavenging if there is transfer port beneath exhaust port on existing cylinders we use today. ..short circuiting comes on my mind immediately .
Loop was abandoned on diesels because of scavenge efficiency, especially when long strokes were introduced.
Uniflow is unbeatable.

Uniflow has it's issues also...

[Haufen]

Haufen, I would say that we have loop scavenging if there is transfer port beneath exhaust port on existing cylinders we use today. ..short circuiting comes on my mind immediately .

I agree, short circuiting will be one of the 'hot' topics if there are transfer ports below the exhaust port. Speaking of hot - as will be temperature and heat transferred to the fresh charge in these ports. The former might not be that worse if the relative angle between the ports and the exhaust port is considered. For ports beneath the exhaust port, the charge would have to make a 180° U-turn to short circuit out of the exhaust. This is more than between the main transfer ports and the exhaust window in the conventional configuration - in most cases at least. The latter could be kept in check by water cooling and careful design of the coolant circuit, especially to shield the transfers from exhaust heat.

This 'Novel Port Design' looks strangely familiar

---

You mean the novel port design by Fleck et al from 2006 which is quoted in the paper in Figure 4? Other than that both designs have ports all around the bore, I don't see any resemblance? One is loop, yours is a symmetrical fountain (is there a correct wording for this?), one has one exhaust pipe, yours has two.

I would love to see the potential of such systems demonstrated on a running engine. From what I understood, getting your FOS system to work has been quite challenging so far - and there are also no results available (?) from the Fleck engine either. From a complexity and novelty (on smaller and high reving engines at least) standpoint, I would put the Fleck Design somewhere between the conventional loop and your FOS design.

[Tim Ey]

I got two questions for the Ignitec Freaks here:

1. Do you also get problems when using "Special" Settings for the bike? I think I killed 1-2 pistons with it &
I stopped using that now and returned to "Classic".

2. Ignitec claims that you need more than 14 Volts when revving over 12krpm. The control unit will be happy with 18 Volts. Battery can be build easily or even taken from a power tool (with balancer inside).
Are there any proper AC-DC regulators that are able to provide 18 Volts?
Or do I need to take a 12V & a 6V regulator and work with two batteries in serie?