2 stroke thread (with occasional F1 relevance!)

All that has to do with the power train, gearbox, clutch, fuels and lubricants, etc. Generally the mechanical side of Formula One.
Big Tea
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by Big Tea » Mon Oct 01, 2018 1:24 pm

J.A.W. wrote:
Mon Oct 01, 2018 12:00 am
See here: https://www.youtube.com/watch?v=YEaE6BHyjzg

2-piece piston designed to reduce mass & improve dimensional-control/sealing - via even thermal expansion.
Brilliant, as long as it does not unscrew :D
Can I make a 3D printer on my 3D printer?

gruntguru
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by gruntguru » Tue Oct 02, 2018 5:06 am

Pinger wrote:
Wed Sep 26, 2018 4:47 pm
. . . . Any backpressure incurred by a PRT would require a corresponding increase in scavenging pressure - a near impossibility with the crankcase as transfer pump. Equally hard to imagine a PRT could be contrived to harness the pulse energy without creating backpressure. . . .
There are many examples of crankcase scavenged 2 strokes adapted for turbocharging.
.
Equally hard to imagine a PRT could be contrived to harness the pulse energy without creating backpressure.
If you read the Wright T.C. info you can see how its done.
je suis charlie

Pinger
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by Pinger » Tue Oct 02, 2018 10:26 am

gruntguru wrote:
Tue Oct 02, 2018 5:06 am
If you read the Wright T.C. info you can see how its done.
Yep, with 2-stage supercharging (and yes, altitude performance was a factor also).

I think we can safely conclude there has never been a NA 2T engine with a PRT - and probably never will be.

gruntguru
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by gruntguru » Wed Oct 03, 2018 5:20 am

No - my point was - a PRT can be configured in a way that captures blowdown energy without creating backpressure during parts of the cycle that would be disadvantageous (with or without supercharging).
je suis charlie

tok-tokkie
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by tok-tokkie » Tue Oct 09, 2018 5:06 pm

That 2 piece piston design. Here is a guy who wants to combine that idea with another that allows a piston ring that is a complete ring. The screwed piece is the complete crown with the wrist pin bit as in the 2 part design. Just the simple cylindrical skirt screws onto the crown. The skirt traps the complete piston ring in its groove. Seems a really good idea to me. What about expansion of a complete piston ring - is that an issue?

https://www.youtube.com/watch?v=JGK-Sa8 ... e=youtu.be

Pinger
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by Pinger » Tue Oct 09, 2018 6:20 pm

gruntguru wrote:
Wed Oct 03, 2018 5:20 am
No - my point was - a PRT can be configured in a way that captures blowdown energy without creating backpressure during parts of the cycle that would be disadvantageous (with or without supercharging).
How can it be so configured - much larger than required/expected relative to the mass gas flow?

Pinger
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by Pinger » Tue Oct 09, 2018 6:23 pm

tok-tokkie wrote:
Tue Oct 09, 2018 5:06 pm
That 2 piece piston design. Here is a guy who wants to combine that idea with another that allows a piston ring that is a complete ring. The screwed piece is the complete crown with the wrist pin bit as in the 2 part design. Just the simple cylindrical skirt screws onto the crown. The skirt traps the complete piston ring in its groove. Seems a really good idea to me. What about expansion of a complete piston ring - is that an issue?

https://www.youtube.com/watch?v=JGK-Sa8 ... e=youtu.be
Struggling to see how an unsplit ring can expand under gas pressure to perform its sealing function.

Mudflap
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by Mudflap » Tue Oct 09, 2018 9:52 pm

The same way a C ring does in static sealing applications I suppose.
How much TQ does it make though?

gruntguru
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by gruntguru » Wed Oct 10, 2018 12:21 am

Pinger wrote:
Tue Oct 09, 2018 6:20 pm
gruntguru wrote:
Wed Oct 03, 2018 5:20 am
No - my point was - a PRT can be configured in a way that captures blowdown energy without creating backpressure during parts of the cycle that would be disadvantageous (with or without supercharging).
How can it be so configured - much larger than required/expected relative to the mass gas flow?
Basically - yes. Of course the exhaust runners must be grouped to avoid overlapping of exhaust events within each group and plumbed to deliver blowdown pulses all the way to the turbine nozzle (which will be the smallest cross section in the runner).
je suis charlie

Pinger
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by Pinger » Tue Oct 16, 2018 8:12 pm

gruntguru wrote:
Wed Oct 10, 2018 12:21 am
Basically - yes. Of course the exhaust runners must be grouped to avoid overlapping of exhaust events within each group and plumbed to deliver blowdown pulses all the way to the turbine nozzle (which will be the smallest cross section in the runner).
With such a configuration, would the pulse be reflected on/after entering the turbine nozzle and if so, would it reflect as a positive or negative pulse?

gruntguru
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by gruntguru » Wed Oct 17, 2018 12:29 am

Pinger wrote:
Tue Oct 16, 2018 8:12 pm
gruntguru wrote:
Wed Oct 10, 2018 12:21 am
Basically - yes. Of course the exhaust runners must be grouped to avoid overlapping of exhaust events within each group and plumbed to deliver blowdown pulses all the way to the turbine nozzle (which will be the smallest cross section in the runner).
With such a configuration, would the pulse be reflected on/after entering the turbine nozzle and if so, would it reflect as a positive or negative pulse?
https://books.google.com.au/books?id=MD ... ne&f=false

Any reflection is an indication that the turbine is not extracting all the energy from the pulse. The linked article states that reflections increase with pressure ratio and pulse turbocharging becomes less viable at high pressure ratios. The reflections are positive - having a negative effect on the exhaust stroke.
je suis charlie

Pinger
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by Pinger » Wed Oct 17, 2018 5:00 pm

Thanks GG - much appreciated.

manolis
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by manolis » Wed Oct 24, 2018 2:24 pm

Hello all.

Here are the moving parts of the OPRE TIlting 2-stroke engine:

Image

Image

Image

Image

Image

Image

The above tilting valves have "rectangle" shape for the shake of the easy / accurate manufacturing with a lathe.

And here are two youtube videos of the engine (manual cranking).





Thanks
Manolis Pattakos

tok-tokkie
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by tok-tokkie » Wed Oct 24, 2018 5:29 pm

I am really pleased to see your progress into running engine. It sounds very smooth & there is no vibration. Looking wonderful. Congratulations.

Pinger
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Re: 2 stroke thread (with occasional F1 relevance!)

Post by Pinger » Thu Oct 25, 2018 12:17 pm

As per the above post Manolis, congrats on getting it built and running. A few questions if you can indulge me please.
Looking at the designated web page, I see some of the claimed benefits (eg, combustion dwell, side thrust on cooler part of piston, etc) but what does the tilting valve bring to the table? Asymmetric timing and if so, in which direction - late? What are the transfer and exhaust timings (if you are prepared to divulge them - fine if you prefer not to)? When do you intend to run it under load and what power output are you expecting?