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.
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Big Tea
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Joined: 24 Dec 2017, 20:57

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

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J.A.W. wrote:
01 Oct 2018, 01:00
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
When arguing with a fool, be sure the other person is not doing the same thing.

gruntguru
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Joined: 21 Feb 2009, 07:43

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

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Pinger wrote:
26 Sep 2018, 17:47
. . . . 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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Joined: 13 Apr 2017, 17:28

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

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gruntguru wrote:
02 Oct 2018, 06:06
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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Joined: 21 Feb 2009, 07:43

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

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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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Joined: 08 Jun 2009, 16:21
Location: Cape Town

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

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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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Joined: 13 Apr 2017, 17:28

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

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gruntguru wrote:
03 Oct 2018, 06:20
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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Joined: 13 Apr 2017, 17:28

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

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tok-tokkie wrote:
09 Oct 2018, 18:06
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.

63l8qrrfy6
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Joined: 17 Feb 2016, 21:36

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

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The same way a C ring does in static sealing applications I suppose.

gruntguru
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Joined: 21 Feb 2009, 07:43

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

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Pinger wrote:
09 Oct 2018, 19:20
gruntguru wrote:
03 Oct 2018, 06:20
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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Joined: 13 Apr 2017, 17:28

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

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gruntguru wrote:
10 Oct 2018, 01:21
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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Joined: 21 Feb 2009, 07:43

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

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Pinger wrote:
16 Oct 2018, 21:12
gruntguru wrote:
10 Oct 2018, 01:21
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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Joined: 13 Apr 2017, 17:28

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

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Thanks GG - much appreciated.

manolis
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Joined: 18 Mar 2014, 10:00

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

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Hello all.

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

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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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Joined: 08 Jun 2009, 16:21
Location: Cape Town

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

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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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Joined: 13 Apr 2017, 17:28

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

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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?

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