Talk:Two-stroke diesel engine

Remove? No, merge

page should be removed as this is already covered by http://en.wikipedia.org/wiki/Diesel_engine— Preceding unsigned comment added by Takarada (talk • contribs) 23:43, 14 March 2008 (UTC)‎

Or merge to Two-stroke engine#Two-stroke diesel engine. – Wbm1058 (talk) 14:06, 16 May 2013 (UTC)

Oppose both. Andy Dingley (talk) 15:24, 16 May 2013 (UTC)

Support Wbm1058. Almost all of this stuff is covered elsewhere. This, plus sections "Uniflow" and "Two-stroke diesel" from "Two-stroke engine" would make a good section. This really should go in Diesel, but that's probably just too bloated, right?Sammy D III (talk) 17:55, 13 March 2014 (UTC)

Or in other words, merge an article on giant ship Diesels into an article on mopeds and lawnmowers, because the words in the titles are a bit similar. Andy Dingley (talk) 18:37, 13 March 2014 (UTC)

That's sort of a cheap shot at someone who has driven both Yamahas and Detroit Diesels. I don't like "Two-strokes" either, it should be in "Diesel engine", but I didn't feel the need to insult anyone.Sammy D III (talk) 19:01, 13 March 2014 (UTC)

Commer Knocker videos

These sites: [only motor] and [truck] have Commer Knocker motor running.Agre22 (talk) 01:22, 28 May 2009 (UTC)agre22

Supercharging 2-strokes not clear?

Sometimes people show up at EMD questioning supercharging, I think I've seen it somewhere else, too. Coming here, it's not all that clear, either. I wonder if people are confused by motorcycles.

"Intake begins when...scavenging." covers supercharging, but it's low key, in the middle of the paragraph. Someone (not me) may want to punch it up, maybe a separate paragraph with "forced induction"! Just a thought.Sammy D III (talk) 15:36, 8 March 2014 (UTC)

Special:Diff/1035300967

Regarding Special:Diff/1035300967:

• "The key characteristic of the diesel engine is that it relies on compression ignition. As air is compressed it heats up." → The Diesel engine is designed around the idea of being the most efficient engine physically possible. The highest efficiency is yielded with the combination of several different techniques, including, high compression, lean burn, cooling down the air during compression (which is impossible, so the next best thing, cooling the air prior to compression is used), using the exhaust gas enthalpy, proper gas flow (no throttling), small combustion chamber surface etc. – the most important of these techniques (lean burn and high compression) can be found on all Diesel engines, and Rudolf Diesel has described them in detail in his thoughts on how to convert the idea of the rational heat motor into a working engine. The result had to be a compression ignition engine, because otherwise, the principle would not work (the fuel would undergo spontaneous combustion during the compression stroke if it was mixted with the air prior to compression). So, in other words, a Diesel engine relies on a high air ratio, and a high compression, which results in compression ignition and quality torque control (="the airflow is not throttled but only the amount of fuel injected at each cycle is varied").

• "Diesel fuel is composed of heavier hydrocarbon oils (…) making it less volatile and giving it higher calorific value. It is therefore easier and safer to handle and potentially more economical." → Describing what Diesel fuel is composed of is not necessary for this article. Two-stroke diesel engines do not operate on diesel fuel (at least modern ones, I'm ignoring Detroit Diesels on purpose because they have been obsolete for a couple of decades now). Diesel fuel according to the EN 590 standard is a mixture of several different hydrocarbons, mostly alkanes. The standard asks for the mixture to have a higher density than petrol, but an ideal Diesel fuel consisting of only alkanes can be lighter than bog-standard petrol. So the density difference is mainly caused by the EN 590 standard. Diesel fuel has to be less volatile than petrol, because otherwise it wouldn't be a fuel well-suited for a diesel engine. But high density does not necessairly mean higher "calorific value" (=lower heating value). That is because carbon (which has a higher density than hydrogen) has a heating value of 33.5 MJ·kg⁻¹, whereas (very low density) hydrogen has a heating value of 125 MJ·kg⁻¹. So in reality, petrol and diesel fuel can both have the same lower heating value of about 42…43 MJ·kg⁻¹. Sure enough, diesel fuel doesn't catch on fire that easily, nonetheless, it is a flammable liquid, and it requires caution when handling. But I don't see how diesel fuel can make things more economical. Two-stroke diesel engines running on low quality <40 MJ·kg⁻¹ marine fuel are more economical than diesel engines running on high quality diesel fuel.

• "(…) petroleum fuel or gas used in spark-ignition engines" → Petroleum is not suited for spark ignition engines – it is way too viscous and would clog up every carburettor. Gases (such as CH₄) work well in spark ignition engines, but comparing gas to diesel fuel is not exactly useful.

• "The disadvantages of the diesel include a high compression ratio, requiring a strong and heavy engine, and the difficulty of obtaining good fuel dispersion for clean, efficient burning." → High compression is not a disadvantage, it is required in internal combustion engines to make them efficient. Two-stroke diesel engines can be as heavy as they need to be with low power to mass ratios because they are installed in watercraft. Additional masses of let's say 1000 kg are negligeable in such applications. Two-stroke diesel engines have to last virtually forever, and they are two-stroke – that is why they have to be strong. Nobody wants an engine that lasts only 10,000 hours. The compression ratio also doesn't have any serious noticeable effects upon the fuel injection process – the problems associated with that are caused by the diffusion flame principle. Nonetheless, diesel engines burn their fuel very efficiently, because otherwise, they'd be totally useless (nobody wants inefficient engines).

• A "complex and overlapping nature of internal processes" sounds cool, but hides its meaning so deep inside that only engineers can understand it. Günter Mau (an excellent source I have cited in this article several times) calls it "scavenging losses" which is far more accurate and way less complicated. The two-stroke principle also doesn't magically make the engine more efficient, it allows producing more torque from the same displacement. This is an increase in volumetric efficiency, but not in efficiency.

• "The two-stroke internal combustion engine is typically simpler mechanically than the four-stroke engine, as it does not need inlet or exhaust valve gear and the accompanying camshaft" → this is only true for chainsaw engines (and other engines alike). This article though is on two-stroke diesel engines. Therefore, this sentence doesn't belong here. Two-stroke Diesel engines work very differently from chainsaw engines. In fact, they are much more complicated, and they ALL have been designed with exhaust valves and camshafts for the last 40 years. Making camshafts for two-stroke diesel engines is a difficult process. And the thermal stress two-stroke diesel engines have to withstand is not negligeable. Thus, two-stroke diesel engines are among the most complicated engines to design and manufacture. There is nothing simple mechanically about them.

• Why exactly does the article have to tell the reader about two non-functioning engines that aren't diesel engines (Rolls-Royce Crecy), or don't have an article (Saurer FLB 1000 and 2000)? That is just nonsense. I reckon this see also section is completely useless in this case, but if you feel the urge to place it in this article, at least link to something that has something to do with the topic (for instance, the Junkers Jumo 205, which is a two-stroke diesel engine that does work and that has been mass-produced).

If you with to add content to this article, please support it with reliable sources. I am allergic to unreferenced false claims. Best regards, --Johannes (Talk) (Contribs) (Articles) 12:57, 25 July 2021 (UTC)

Well, dare I say it seems a bit hypocritical to supply no English-language RS yourself but to demand that others do. Also, please be aware that near-native fluency in the English language is not native fluency. For example in British English, what the Americans call gasoline is what we call petrol, which is short for petroleum spirit. The phrase "petroleum fuel" strictly refers to any fuel derived from petroleum oil stock, so neither of us was quite right there. But a simple edit for correctness or, failing that a templated tag for citation or clarity, is normal WP:ETIQUETTE; bland deletion, especially when one has fallen victim to one's own criticisms, is not acceptable behaviour. So let us stop this allergy garbage and focus on improving the article through constructive cooperation. — Cheers, Steelpillow (Talk) 15:47, 25 July 2021 (UTC)

Characteristics of the diesel

Your first bullet point, definition of a diesel engine. The main article lead states, "The diesel engine, named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to the mechanical compression; thus, the diesel engine is a so-called compression-ignition engine (CI engine)." This article should adopt the same consensus definition; if you beg to differ, then argue the point at Talk:@Diesel engine first and then bring any agreed consensus change across here. I'll restore the consensus version and remind you that you should not conflict with consensus unless you can produce adequate RS to back your claims. — Cheers, Steelpillow (Talk) 15:47, 25 July 2021 (UTC)

Hellow Steelpillow, WP:RS doesn't specify the language sources ought to have, so I reckon German language sources are acceptable. Admittedly WP:NOENG states that English-language sources are preferred over (in this case German) ones, however, it also states that English-language sources need to be available and of equal quality. Mau's book was sadly never translated into English, but it is of excellent quality (much of its content is still not obsolete almost 40 years later), and I don't know of any English-language books that are of equal quality (which doesn't mean that such sources don't exist, but I dare say that their content would not differ much from Mau's book anyway). Maybe I have been a bit too hypocritical with the petroleum fuel, but this was just the tip of the iceberg, so I'd say no big deal (and no tags required). I have provided a decent explanation of why I have removed content, so this I'd say it's far away from a "bland deletion". I am here to improve the article's quality, which is why I have Mau's book in close vincinty. Either way, I agree that constructive cooperation is what we need. I find your definition of consensus interesting, but it's pretty clever. I am not particularly happy with this edit Special:Diff/1035426082 because it confuses a causal chain slightly (lean mixture and high compression make the engine more econimical, but the lean mixture is not caused by the compression ignition, it is caused by the injection metering device metering only a small amount of fuel; lean burn is a principle not only used in compression ignition engines). But I think that the wording "Together with the high compression ratio, this makes it more economical than the petrol or gasoline Otto engine" is an improvement, so I can pretty much live with the edit. Best regards, --Johannes (Talk) (Contribs) (Articles) 17:47, 25 July 2021 (UTC)

Diesel fuels

Next bullet point. You feel that "Describing what Diesel fuel is composed of is not necessary for this article." I would beg to differ. The properties of the fuel affect the characteristics of the engine and contribute significantly to the pros and cons of the engine type. You have gone into great detail in order to make your points here, you cannot seriously sustain the argument that not even a short overview is needed in the article, to get the same basic points across. You claim that "Two-stroke diesel engines do not operate on diesel fuel." That is not consistent with other articles. The article on Diesel fuel states that "Diesel in general is any liquid fuel specifically designed for use in diesel engines". What we can say is that say marine diesel oil has a different composition from what we in the UK used to call DERV. You may be right over the calorific vale in terms of energy per kilogram. But all that needs is a simple substitution for energy density, not wholesale deletion. For aircraft especially (which is where I am coming from) the higher density, compared to petroleum based aviation fuels, allows smaller fuel tanks and a lighter airframe that requires less energy for a given performance. For long-range types, this can more than offset the extra weight of the high-compression cylinders. This was one of the reasons why the Junkers Jumo 204 and its derivatives were widely used and license-built from the 1930s. The article needs to acknowledge this. By the way, the Napier deltic was a two-stroke diesel derived from the 204/5 and quite widely used in the UK for railway and marine applications. I don't know whether the railway and marine versions used different grades of fuel. — Cheers, Steelpillow (Talk) 10:38, 26 July 2021 (UTC)

This is an article on two-stroke diesel engines. What has been associated with that term for the past 40 years are almost exclusively large two-stroke marine engines that operate on HFO (also known as Bunker C). Sure enough, these engines would run fine on diesel fuel, but that would be way to expensive. Nobody would do that. The properties of the engine affect the requirements for the fuel – the fuel properties don't affect the engine so much. (And well, energy density doesn't affect engine efficiency at all, just saying, so it's not necessary to mention here either.) Aircraft diesel engines (which are typically four-stroke engines by the way) also don't operate on diesel fuel – this is because of both fuel cost and logistics. Airports provide relatively inexpensive Jet A-1 fuel and AvGas. Aircraft diesel engines are designed to operate on the former (which, on modern diesel engines, requires modifications to the fuel system, because Jet A-1 and diesel fuel have slightly different characteristics). Again, you could go to the next petrol station, get tons of jerry cans, fuel regular diesel fuel into your diesel engined aircraft, the engine would run, but who would buy expensive diesel fuel for his airplane if Jet A-1 is so much more readily available? The Jumo engines were designed before diesel fuel was "invented". So they were also not designed for diesel fuel. The key here is that the diesel engine has never been designed to operate on a certain type of fuel. It is, by principle, a multifuel engine. By design, however, diesel engines can be made to run only on a narrow range of fuels (because of performance, size, mass, reliabilty, etc. considerations). EN 590 Diesel fuel is a compromise of several different characteristics: It is cheap, easy to produce, allows engines designed for high-quality fuel, gives decent performance, and acceptable exhaust gas behaviour. This is what is needed for cars and lorries. In the United States, things have long been different: The fuel mainly had to be cheap, so it was less prone to compression ignition, and it contained pollutants like sulphur. In engines designed for such fuel, it would run. In modern 2.0 TDI engines, however, this fuel would make the engine perform worse than what is to be expected from such an engine. And, as I have said, EN 590 is not even an "ideal diesel fuel". It is just a compromise. "Ideal diesel fuel" would possibly not work in modern diesel engines because of their fuel systems. "Modern" two-stroke diesel engines though are not designed to operate on diesel fuel, and, therefore, this article doesn't need to describe diesel fuel. Günter Mau writes (in 1984): "Over the course of the past 25 years, four different classes of fuel have been introduced to the [marine] market as regular products: Marine Gas Oil, Marine Diesel Oil, Intermediate Fuel Oils, Bunker Fuel Oil." (p. 309) "(…) Marine Gas Oil is, regarding its chemical and physical properties, equivalent to diesel fuel sold at petrol stations (…) The slightly higher density (…) results from a slightly longer destillation process." (p. 310) "The petroleum industry considers all heavy, and black fuels to be residue oils – in shipping, two such fuels are used: Bunker Fuel Oil, and Intermediate Fuels. These two fuels are the most common fuels in shipping" (p. 311). As for Napier Deltic engines, I don't know which fuel they were designed for. But I am sure that the manual doesn't recommend EN 590 diesel fuel. Best regards, --Johannes (Talk) (Contribs) (Articles) 11:54, 26 July 2021 (UTC)

This is an encyclopedia. Mainstream is one thing, but other verifiably notable aspects also need to be included and the whole article should not contradict itself. The Junkers Jumo 204 was the first of an important family of two-stroke diesel aero engines and does need to be addressed. Also, you really do need to take on board the consensus view here that "Diesel fuel" is any fuel burned in a Diesel engine. If Bunker C is the commonest fuel for marine two-stroke diesels then say exactly that, and either link to the article that says so or, better still, cite your source. But do not delete engines which burn other fuels just because you don't like them. (By the way, WP:CONSENSUS is not especially clever, it is merely a policy of the English-language Wikipedia which we are obliged to follow.) — Cheers, Steelpillow (Talk) 12:28, 26 July 2021 (UTC)

Since there are so many different grades burned in diesel engines, I have used the term in the plural, as "diesel fuels". But I still assume the definition given in the main article on the subject. I agree that there is no need to spell out all the complications. — Cheers, Steelpillow (Talk) 13:36, 26 July 2021 (UTC)

Any fuel burnt in a diesel engine is not diesel fuel. The diesel engine is a multifuel engine by principle; imagine if I fuelled petrol into my MAN 630 Diesel lorry – by that definition, the engine could convert petrol into diesel fuel. I suppose it is obvious that any such magic doesn't exist. Diesel fuel is fuel specifically designed for on-road diesel engine applications, or, in "super precise": fuel according to the Euronorm 590 standard. That is the easiest definition of diesel fuel, and whenever people talk about diesel fuel, they mean EN 590 fuel. The source that I have cited (and translated into English) defines what fuel is used in two-stroke diesel engines. It also explains how these fuels are referred to (and it also explains that there are dozens of names for these fuels which explains why finding a proper term is so difficult). But please – I understand your interest in aircraft diesel engines – modern aircraft diesel engines are not related to this topic. That is because they are modified four-stroke passenger car engines. They are not two-stroke marine engines what this article is about. Yes it is true that in recent years, aircraft diesels have seen some sort of revival (I have looked up diesel engine aircraft just two days ago, so you're not the only one interested in that matter). And it is easy to cite a source for that. But it makes no sense to write about this topic in this article. I will look up sources for the Junkers engines, I bet that they are notable for this article, and I suppose it's not difficult finding proper sources for that. But modern aero diesels do not belong here. Best regards, --Johannes (Talk) (Contribs) (Articles) 16:48, 26 July 2021 (UTC)

It's no good flatly contradicting the definition given in the main article on diesel fuel. You have to revisit the consensus established there, first. You need to open this discussion at Talk:Diesel fuel. Meanwhile, this article is not titled "Marine two-stroke diesel engines", please be realistic about this. You reverted a cited paragraph on aero engines, which are well within the scope of the article title. You may fork your marine article if you wish, but I'll bet it gets merged back here. — Cheers, Steelpillow (Talk) 17:28, 26 July 2021 (UTC)

The definition is "diesel fuel is any liquid fuel specifically designed for use in diesel engines". Specifically designed for diesel engines. Bunker fuel is not specifically designed for diesel engines, it is the lowest quality fuel that can be made from petroleum. If it was specifically designed for diesel engines, it would have different chemical and physical properties. It's just that somebody realised that the fuel for steam-powered vessels ("oil") could also be used in diesel engines. I know that this article is not titled marine two-stroke diesel engines, but the vast majority of two-stroke diesel engines belong into the marine category. In fact, all modern two-stroke diesel engines are marine engines. Non-marine two-stroke diesels have been obsolete for the past 30 years at least. Modern aero diesels are not two-stroke diesels! You can cite that diesel engines are used in aircraft, but why exactly does it belong here? I don't see why, and I bet there is absolutely no reason for that. I could also write about Wankel engines being used in drones and place an excellent citation in that paragraph. It would still be nonsense. The reason why modern aero diesels are passenger car engines is simple: Mass and price. They are only suitable for small aircraft. Two-stroke diesel engines for aircraft were rendered obsolete by the invention of the turboprop engine – it is slightly less efficient than a diesel engine, but significantly lighter, which makes it more efficient than a two-stroke diesel engine in an airplane. Therefore, two-stroke aviation diesel engines have not been made in the past 70 years or so. This is an obsolete technology that even old books don't mention. I am currently looking through old books on the subject. Best regards, --Johannes (Talk) (Contribs) (Articles) 17:48, 26 July 2021 (UTC)

Aircraft diesels

• J. Zeman: Zweitakt-Dieselmaschinen kleinerer und mittlerer Leistung, Springer, Wien 1935, ISBN 978-3-7091-5145-7. This book is a (sadly old) monograph on two-stroke diesel engines of the small and medium power output variety. It mentions the existence of Junkers aircraft diesel engines in its list of literature on page 245. However, on page III, the author writes that he has no experience with opposed piston engines, which is why he has omitted them in his book.
• Paul Henry Schweitzer: Scavenging of two-stroke cycle Diesel engines, Macmillan, New York 1949, p 8.: "Another uniflow type of two-stroke cycle is the opposed-piston engine, originally invented by the German professor Junkers. Two pistons move in the same cylinder, opposite each other, and the combustion takes place in between. Fresh air is admitted through a row of ports at one end of the cylinder, and exhaust takes place through another row of ports at the other end. One piston controls the inlet and the other piston controls the exhaust. As a result the long cylinder is effectively scavenged. In brake mean effective pressure the opposed-piston engine is at par with the exhaust poppet valve engine."; (in table 18-I the bmep is stated as 600 kPa) p. 19: "To the turboblower a mechanically driven blower is added, which is gear-driven from the crankshaft. The turboblower forms the first stage and the mechanical blower the second stage of the compression. At start or at low load the turboblower does not contribute to the compression of the charge, but the air furnished by the mechanical blower alone is sufficient to operate the engine. At heavy load the effort largely shifts to the exhaust driven blower with the result that a handsome boost in power output is obtained without the penalty of increased specific fuel consumption. This scheme was used during the war in the German Junkers aircraft diesels. Work along this line is still in progress."
• Richard van Basshuysen (ed.): Ottomotor mit Direkteinspritzung und Direkteinblasung: Ottokraftstoffe · Erdgas · Methan · Wasserstoff. 4th edition, Springer, Wiesbaden 2017, ISBN 978-3-658-12215-7. p. 6: "Direct fuel injection at Junkers originated from the 1914 idea of making an economical and fire-safe aircraft diesel engine for the developing aircraft industry. The engine design was of the flat opposed piston type with two mechanically connected crankshafts. This design proved to be successful in the series-produced Junkers Jumo 205 and 207 aircraft diesel engines. Despite the belief in the diesel principle, the first Junkers M 03 prototype four-cylinder diesel engine made in 1915, displacing 7,238 cm³, was a failure."
• Konrad Reif: Dieselmotor Management – Systeme, Komponenten, Steuerung und Regelung, 5th edition, Springer, Wiesbaden 2012, ISBN 978-3-8348-1715-0, p. 102: "Aircraft diesel engines have been developed in the 1920s and 1930s (…) the biggest problem with designing such engines was greater mechanical and thermal stress. The most successful series-production aircraft diesel engine was the six-cylinder, two-stroke, opposed-piston, heavy fuel oil Junkers Jumo 205 engine. (…) Approximately 900 units of this reliable engine have been built. (…) Due to improvements in high-performance Otto engine and fuel-injection technology, aircraft diesel engine design became unappealing."
• Klaus Mollenhauer, Helmut Tschöke (ed.): Handbook of Diesel engines, Springer, Heidelberg 2010, ISBN 978-3-540-89082-9, p. 300: "many firms throughout the world saw themselves induced in the 1930s to work on the development of aircraft diesel engines to counter the danger of altitude induced misfires and achieve higher efficiencies. Out of a total of twentyfive projects, twelve engines were air-cooled, yet only Junkers’ Jumo 205 water-cooled opposed piston engine was produced in larger quantities."
• Karl A. Zinner: Aufladung von Verbrennungsmotoren – Grundlagen · Berechnungen · Ausführungen, Springer, Berlin/Heidelberg 1985, ISBN 978-3-540-15902-5, p. 17: "The first turbocharged two-stroke aircraft engine made by Junkers was the Jumo 205, tested in 1939."

Conclusion: Two-stroke aircraft diesel engines are a 1930s technology. There has been only one successful design, the Jumo 205, with about 900 units built. It was designed to run on heavy fuel oil. This technology deserves mentioning, but that's basically it. Best regards, --Johannes (Talk) (Contribs) (Articles) 18:36, 26 July 2021 (UTC)

And you refuse to let any of this into the article, because you don't like it's not being marine. You even deleted a citation on recent renewed interest, together with a link to an article on a recent development project That is not how Wikipedia works. — Cheers, Steelpillow (Talk) 18:26, 26 July 2021 (UTC)

Just some thoughts of mine: the Thielert Centurion 1.7 aircraft diesel engine is a modified four-stroke Mercedes-Benz OM 668 engine from a 168-series Mercedes-Benz A-Class. It is a certified engine that (at one point) you could buy, like, a serious product, and not some prototype that suddenly rescues the stagnating aero industry because its revolutionary technology magically saves 2 gallons of fuel per flight hour. Modern two-stroke diesel engines for aircraft have been discussed, some prototypes have been made, but this technology has not found its way into any serious series production product. We are not here to guess why, but I'd say that the fuel consumption is too high (255 g/(kW·h) for a 1.5 litre V6 rated 100 kW). I have just read the 2014 scientific paper A new design concept for 2-Stroke aircraft Diesel engines by Giuseppe Cantorea, Enrico Mattarellia, and Carlo Alberto Rinaldinia. Sounds like such an engine exists, right? Well, this scientific paper is based on a CFD simulation. An actual engine has never been built. But, as of now, the Jumo 205 remains the only series-production two-stroke aircraft diesel engine. Best regards, --Johannes (Talk) (Contribs) (Articles) 19:01, 26 July 2021 (UTC)

Another paper from 2019, published under the CC BY-ND 4.0 licence: KARPIŃSKI, P., PIETRYKOWSKI, K., and GRABOWSKI, Ł. (2019). Turbocharging the aircraft two-stroke diesel engine. Combustion Engines, 178(3), pp.112-116. https://doi.org/10.19206: /CE-2019-319

I have decided to comment, so I wish to highlight that these comments are just my personal opinion.

• "In two-stroke opposed piston engines, an external device as a mechanical compressor or turbocharger is necessary to carry out the load exchange process." → This adds the probability of the engine suddenly failing mid-flight: In small engines, mechanical blowers are driven by belts, which can perish. Therefore, such engines need to incorporate some sort of additional backup system that provides boost (e. g. a turbocharger), which adds to their mass and complexity. However, if the turbocharger also fails, the engine stalls. Four-stroke engines are safer in this regard, because they can still operate if their supercharging system fails (albeit at reduced power and efficiency). Also, the paper outlines that the mechanical blower in the two-stroke aircraft engine is unable to provide sufficient results. It consumes too much engine power, which results in low cruising power and high fuel consumption.

• "The research object was a three-cylinder two-stroke opposed piston aircraft diesel engine at the design stage. (…) In order to perform simulation tests in the AVL BOOST software, a zero-dimensional model of the tested engine in two variants was developed" → Sounds pretty much like the engine was only simulated in software. A functioning, market-ready two-stroke diesel engines doesn't exist (in 2019).

Best regards, --Johannes (Talk) (Contribs) (Articles) 12:53, 27 July 2021 (UTC)

One minute you delete my cited additions on aeroplanes because you demand that this article be only about marine diesels. The next you post your own take on aircraft diesels. This looks very like a blatant case of WP:OWNERSHIP. Please can you explain your actions. — Cheers, Steelpillow (Talk) 14:39, 27 July 2021 (UTC)

"(…) with two-stroke examples such as the Superior Air Parts Gemini Diesel 100 under development as of 2015." → No references (not a big deal, and that's not the main problem here). More importantly, development alone doesn't mean that the "modern two-stroke aircraft engine" is notable. That is because development can range from a computer-simulated concept to an almost market-ready engine. In this case, the former is what's going on. Just to put this into comparison: One of my colleagues is currently working on an ethanol-fuelled diesel engine. It is still far away from a marketable product, and has only covered dyno runs. But unlike a modern two-stroke aircraft engine, this thing exists in a lab, and you can touch it with your hands. Still, it is not notable.

There are strong indicators that a two-stroke aircraft diesel engine is unfeasible (see my 13:53 comment), while on the other hand there is no evidence that a market-ready two-stroke aircraft engine exists (no coverage in monographs or equivalent books). Personally, I am a huge fan of uncommon technical designs – I'd argue that, for instance, a two-stroke aircraft engine is such an uncommon (maybe unreasonable) design. However, unlike, let's say the (also unreasonable) "https://d-motor.eu/ modern flathead engine]", the two-stroke diesel engine is not a thing that exists and that you can buy. Scientific papers are, in general, good sources, but I doubt that they alone create notability in the sense of WP:N for this particular article. That is because the "marine portion" of the two-stroke diesel topic is so huge. After all, only about 900 proper two-stroke aircraft engines have been made. Compared against the number of two-stroke marine engines built, this number is small. Now, however, we are comparing 0 modern two-stroke aero diesels against the number of marine engines. This renders the modern two-stroke aero diesel nonnotable.

This is the reason why I have removed the "modern two-stroke aero diesel section" – it is dubious whether this technology exists in practice (and that means existing as a real, running engine, not as a computer simulation). I have also not demanded that this article should only be about marine diesels. However, reliable sources suggest that the vast majority of two-stroke diesels are in fact marine engines. Wikipedia should follow the reliable sources' standpoints. Also, I have not posted my own take on aircraft diesels (emphasis on plural), I have described the only two-stroke aircraft diesel engine that is notable (because it is covered in so many different books; the reason why it's covered is because it is (or was) an actual thing that proved to be successful; it wasn't a computer-simulation). Reif explains why this technology is now obsolete, and Mollenhauer and Tschöke write that there has only been one notable two-stroke aircraft diesel engine (and they still claim this in the 2018 German edition of the book, which I think is recent enough). Best regards, --Johannes (Talk) (Contribs) (Articles) 15:26, 27 July 2021 (UTC)

Mate, why are you doing this Special:Diff/1035769261 to me? Please. Two-stroke diesel engines for marine use do not run on diesel fuel. The Junkers Jumo 205 (the only proper two-stroke aircraft diesel engine ever made) does not run on diesel fuel. Why exactly are you reposting the section on diesel fuel if it is clear that, maybe 0.1 per-cent of all two-stroke run on diesel fuel, whereas 99.9 per-cent do not? Especially when that section outlines that the properties of diesel fuel make it "attractive in some applications such as Aircraft diesel engines"? Two-stroke aircraft diesel engines specifically designed for diesel fuel do not exist – this means that the sentence applies to 0 per-cent of all two-stroke aircraft diesels, or, in other words, to none. All aircraft diesel engines for which your claim is true and makes sense are four-stroke passenger car engines that do not belong here. In this case, your sentences are misleading. What you write is not wrong, in fact, it is perfectly fine and I belive correct to a degree that it is acceptable on Wikipedia, but it does not belong here in this context in this article. It is exactly as useful as describing petrol and oil mixtures just because two-stroke chainsaw engines use this type of fuel. And the interest in aircraft diesel engines has only resulted in modern four-stroke engines, not in functioning two-strokes. Concepts such as the Superior Air Parts Gemini Diesel 100 have been worked on for how many years? Six? And how many engines have been made for purchase? I suppose that's impossible to express in natural numbers unless 0 is included. Best regards, --Johannes (Talk) (Contribs) (Articles) 15:54, 27 July 2021 (UTC)

The answers to your queries and concerns are in my previous comments. I feel there is little point in repeating myself. — Cheers, Steelpillow (Talk) 18:06, 27 July 2021 (UTC)

Anyway, I take your point about whether the fuel is purpose-developed for diesel use, and so I have edited my additions accordingly. I should also like to thank you for your extensive translations of quotes from your sources above here. If I can find the time, I will try to add them as notes to the article. — Cheers, Steelpillow (Talk) 03:11, 28 July 2021 (UTC)

Hello Steelpillow, I think your last-night edit Special:Diff/1035854525 is a vast improvement, thank you! I have since fixed minor wording issues (but I am good at producing such issues myself – "out of about several engines", "sea-going watercraft"…) Best regards, --Johannes (Talk) (Contribs) (Articles) 10:38, 28 July 2021 (UTC)

Technology

Two stoke diesel engine optimization 2402:4000:B194:98D2:52C:47FB:9D13:7AC3 (talk) 14:00, 5 December 2021 (UTC)

And what's with that? Best regards, --Johannes (Talk) (Contribs) (Articles) 14:11, 5 December 2021 (UTC)