Talk:Compound engine

Overlap
While some of this material is new to Wikipedia, some has been taken from other Wikipedia articles. In no case have I moved it.

Some of this material was even already duplicated at steam engine and compound steam engine, notably the excellent diagram of the triple-expansion unit. So some material which was already duplicated is now triplicated.


 * On reflection, I've removed that particular diagram and replaced it with a cross-section of a four-stage unit, which probably makes this article a little less impressive but increases the information value of Wikipedia as a whole IMO, in that many people will see the three-stage diagram in the other articles. Andrewa (talk) 17:52, 8 December 2012 (UTC)

That's not necessarily a bad thing if it makes each article a better treatment of its topic. But some of the duplicated or even triplicated material might also be better in one place or the other, to reduce article bloat.

And some material not even duplicated is probably not in the best article for it.

This and the interlinkages such as main templates will need some work after this page goes live. Andrewa (talk) 02:00, 8 December 2012 (UTC)

In particular, some material should probably be split out of steam engine, which is already fairly long, and a section created there on the topic condenser (steam engine), on which we do not seem to have a general treatment anywhere. At the very least navigation needs further improvement. Andrewa (talk) 05:06, 8 December 2012 (UTC)

Diagrams
File:Cross compound engine, end section (Heat Engines, 1913).jpg also looks good, but need more illustrations of internal combustion compound engines first for balance. Andrewa (talk) 04:59, 8 December 2012 (UTC)

File:Steam Engine 18 478 S 3-6 2009-10-11.jpg is possibly a better image of a coupound locomotive, as the four cylinders and the smaller size of the central high-pressure cylinders are all visible. Andrewa (talk) 20:29, 12 December 2012 (UTC)

Turbines
Do you want to include turbines in this article? We have Compound turbine, Compounding of steam turbines and Pressure compounding in turbines. Biscuittin (talk) 14:48, 8 December 2012 (UTC)


 * Good catch! Yes, there should be links to these articles, and I need to clarify the terminology both in my own mind and the draft article.


 * Those three articles have issues of their own. Compound turbine is a stub with no references or citations at all. Compounding of steam turbines has six scholarly and relevant looking references but no inline citations, and a merge notice posted last May which is not only undiscussed so far, there is no article talk page at all. Pressure compounding in turbines is another stub and completely unreferenced and the other half of the merge request, but as both halves use template:merge without any discuss= parameter, they point to different talk pages. (This IMO highlights a gap in the current documentation, the proposer has merely followed the instructions at template:merge, which tell you how to use the discuss= parameter but make no mention of why you should use it on at least one of the pages to be merged.) No matter, there's no discussion there either anyway. I will fix the merge request.


 * Looking at it! But a very good catch, thank you. Andrewa (talk) 17:45, 8 December 2012 (UTC)

Going live
This page was created in response to Talk:Compound steam engine, and it's IMO time to take it live. Andrewa (talk) 17:28, 23 January 2013 (UTC)

And apologies, I should probably have listed this as a technical move but made a silly mistake when seeing whether it would move without use of admin powers. And the easiest way to then clean it up was to complete the move which then did require admin powers, owing only to a bug fix which had made the insignificant edit history look significant to the software. Apologies if anyone sees that as an abuse of admin powers, and happy to go to RM if anyone wishes.

Anyway, we're live. Andrewa (talk) 17:46, 23 January 2013 (UTC)

Carnot's theorem
I was surprised to find no mention of Nicolas Carnot's theorem (thermodynamics), proved 19 years after Arthur Woolf's 1805 invention of the compound engine, in this or any other article involving compound engines. The theorem states that no heat engine can have a mechanical efficiency greater than the difference between the input and output temperatures, as a fraction of the input temperature. Practical cycles introduce additional losses besides that of the optimal Carnot cycle for any given temperature difference, but the efficiency of all cycles commonly encountered in practice is improved by increasing that difference. Vaughan Pratt (talk) 18:08, 11 October 2016 (UTC)
 * I'm against the existence of this article as being too broad, with a scope that will only rarely be understood, and think it would be better as just the separate articles on obviously recognisable topics. However, if we do have "compound engine" as an article, then Carnot is essential. Andy Dingley (talk) 20:10, 11 October 2016 (UTC)