Talk:Four-stroke engine

message: This article was vandalized over several edits on 11 October 2007.  My first attempt at undoing the vandalism left some junk still in the article and it took me a few tries to recover all the deleted content, sorry about the flood of edits.  The result, or at least the intent, was for the current (163698357) revision to be identical to the one six revisions back (163691542).  What I really needed was to view the differences to an old revision as part of the preview, but oh well.  -- TSylvester 00:52, 11 October 2007 (UTC)
thread_title: Vandalism

message: The animation appears backwards, is much too fast, does not label the air and fuel intakes, and it is not even clear when the fuel is ignited, nor where the exhaust goes.68.5.64.178 07:42, 4 November 2006 (UTC)
thread_title: Concerns about the animation

message: I have looked through the engine section on Wikipedia and I have some serious concerns about the terminology, which I feel is misleading or inaccurate. I should mention that I have no problems with the content of the articles. I have a degree in mechanical engineering and a strong background with engines, which alone should not give me unquestioned authority here. But rather, I'm hoping that my opinion and research will at least be considered and discussed. I have outlined below my list of problems with the terminology here:
*A four-stroke engine is NOT the same as an Otto cycle engine. There are four-stroke cycles that are NOT Otto cycles, mainly the Diesel cycle. This is, in my opinion, the most serious error.
*I submit that an Otto cycle engine does not necessarily need to be four-stroke. The generally accepted definition of the Otto cycle (which is an idealized cycle) is based on the thermodynamic cycle - isentropic compression, constant-volume heating, isentropic expansion, constant-volume heat rejection. This cycle is concerned only with the compression and power strokes. Whether or not there are intake and exhaust strokes is irrelevant. (Of course, adding boost or backpressure changes the cycle but these are not ideal for a naturally aspirated engine.) The very first paragraph in Internal Combustion Engine Fundamentals by Dr. John B. Heywood (which is considered to be one of the premier authorities on engines) reads, "The internal combustion engines which are the subject of this book are spark-ignition engines (sometimes called Otto engines, or gasoline or petrol engines, though other fuels can be used) and compression-ignition or diesel engines." This quote is being posted under fair use policy. Dr. Heywood (and I) equate the Otto cycle to an ignition by spark, and NOT to a particular number of strokes. Additionally, he equates the Diesel cycle to compression ignition. Throughout the rest of his book, he uses the terms "spark-ignition" and "compression-ignition" almost exclusively to differentiate between engine types. It is my opinion that this terminology is the most accurate and most descriptive way to categorize engines, and I suggest that it be used throughout all Wikipedia engine articles. 
Any responses to my request?
Why the hell is the Otto Cycle redirected to a four-stroke engine section? The Otto cyle is an ideal cyle for a petrol engine. The Diesel cycle is also four-stroke, but it is different to the Otto Cycle. 61.69.176.55 (talk) 00:35, 30 December 2008 (UTC)
replies: text: I also think that the ideal Otto cyle should be explained separately. As a Physics teacher I am more interested in the ideal model than in the real four-stroke engine. I think that the material contained in the MIT Open course should be an adequate starting point.--Gonfer (talk) 17:31, 15 May 2009 (UTC)
replies: text: The term 'four-stroke' is widely used as a synonym to the Otto cycle, but I agree with you when you say this is incorrect terminology. I urge you to start editing. This article as well as the Diesel-related articles all require some major reconstruction, as much of the terminology is incorrect and the loose connections between an idealized cycle and a real world engine application needs to be set straight. - Victor van Poppelen (talk • contribs)
The Otto cycle and four-stroke cycle are different things. I came to this article hoping to explain to a friend the difference between the diesel and otto cycles, and instead found a rough description of the four-stroke cycle that conflates the diesel and otto cycles as if they are the same thing. I agree with a move to reconstruct - this article would make a good base for the definition of four-stroke and the otto cycle could be described properly.
I would have to think there should be a differentiation between 4 stroke and 4 cycle.  There are six distinct cycles in a four stroke  gasoline spark ignition engine: 1. Intake, 2. Compression 3. Combustion 4. Blowdown 5. Exhaust 6. Overlap
The 'blowdown' period when the piston is on the power stroke and the exhaust valve opens until it reaches BDC.  Once the exhaust valve is open, power is no longer being produced in the cylinder and the expanding hot exhaust gasses are already moving out the exhaust system.  This is key to efficiently evacuating exhaust gases, as using the piston to push out the full volume of exhaust gas from the cylinder would result in severe losses to power. 
The overlap period is also a key cycle in the four stroke gasoline spark igniton engine.  It is the period near TDC exhaust when both the intake and exhaust valve are open at the same time.  During this cycle the exhaust gases are exiting the cylinder, and as the intake valve opens the velocity of the exhaust gases exiting the cylinder cause fresh air to purge the cylinder of any remaining burning gases for a brief instant before the exhaust valve closes.  —Preceding unsigned comment added by 216.139.21.100 (talk) 06:14, 28 March 2008 (UTC)
thread_title: Serious concerns about terminology

message: I'm removing the following paragraph since it looks unencyclopedic to me. I can't see any way to fix it and, honestly, no reason for such a mnemonic in an encyclopedia (it's not a high school clue sheet) --- cbraga 20:40, Jun 9, 2004 (UTC)
:One way to remember the four strokes and their functions is the series "suck, squeeze, pop, phooey", or alternatively "suck, squeeze, bang, blow". The four "strokes" are also present at each stage of a jet engine, where they are performed simultaneously rather than as a sequence.
And yet it is notable as a mnemonic (used for instance to answer a four year-old's question, "how do cars work"). But if it has no place in wiki, so be it. Agingjb (talk) 12:44, 17 September 2015 (UTC)
thread_title: mnemonic paragraph

message: The 4-stroke animations are broken.  They don't run in Windows Media Player 9 or Winamp, as far as I can determine.  They should be fixed or removed.  Quicksilver 19:15, 15 Jun 2005 (UTC)
thread_title:  Animation 

message: Cool animation!! I would like to point out that 99.99% of all IC engines rotate clockwise when looking at them from the front. The "funny" rotation immediatly seemed un-natural to me. However, this view could be looking at the engine from the flywheel end, or the 2nd engine in a contra rotating marine application. 
The monikers: suck, squeeze, bang, blow were taught in the U.S. military. 
69.213.205.190 18:03, 5 October 2005 (UTC)
thread_title: Animation Direction

message: According to
*Hardenberg, Horst O., The Middle Ages of the Internal combustion Engine, Society of Automotive Engineers (SAE), 1999
the 1862 Otto (O#O) engine did not have exactly the modern four stroke cycle and did not work for long.
Also it says he knew nothing about Carnot and discovered the advantages of compression by turning the flywheel backward by hand!  David R. Ingham 06:13, 6 January 2006 (UTC)
thread_title:  History 

message: I agree with Fyre4ce about the problems with this article.  The "four-stroke cycle" describes a particular operating concept for an internal combustion reciprocating piston engine; it is not a synonym for the Otto cycle (despite the fact that Otto's first engine was indeed a four-stroke).
The Otto cycle is an idealized thermodynamic model of the processes taking place in a gasoline, spark-ignited engine; the title "four-stroke cycle" should be restricted to a page describing the details of operation of a real four-stroke piston engine (e.g. valve timing, output limits, volumetric efficiency, etc.), and a page describing the Otto cycle should be far more focused on the ideal thermodynamic cycle (isentropic compression/expansion, constant volume heat addition, constant volume heat rejection, and the analyses that fall out of that simple model).  See the page on Carnot Cycle to get an idea of what I'm talking about.   It's fine to enumerate the differences between reality and theory, but in writing about a theoretical construct, the focus ought to be on the details of that construct.
I'd be happy to help rewrite an article, but I don't know anything (yet) about the shorthand used in producing things like integrals and section headings.  IOW, I'm not ready yet.  I will need to study the "how to edit a page" guide first.
Joe Frickin Friday 18:14, 27 January 2006 (UTC)
thread_title:  terminology and focus problems 

message: There is a lot of confusion here, and this does not seem the best place to discuss these things.  Rod/stroke ratio seems independent of which cycle is used.  Without supercharging, the output limit depends most on the air intake.  I suggest starting over.  David R. Ingham 07:04, 7 March 2006 (UTC)
thread_title:  "Output limit" paragraph 

message: The reverted edit [] reminds me of Coleman's abnormal psychology textbook (I think that may be Coleman, James C. (1964). Abnormal Psychology and Modern Life  (3rd ed.). Illinois: Scott, Foresman and Company.  Or the first edition, 1950.)  His example was a boy who was sexually aroused only by exaust pipes.  This edit is similar.  David R. Ingham 04:41, 8 March 2006 (UTC)
thread_title:  motor fetishism 

message: Some typical and maximum efficiency levels would be useful. Tobyw 12:29, 8 March 2006 (UTC)
thread_title:  Efficiency 

message: Some formatting needs to be fixed in this section, there's a random "Headline Text" thing and some writing that goes on forever off to the right (at least in Safari) Thetrump 23:06, 6 April 2006 (UTC)
thread_title:  valve clearance adjustment 

message: I'm certainly biased (since I made them) but I'm somewhat dismayed to see the individual illustrations of each stage in the cycle replaced by a single animated .gif (this edit). While the new animation is very nice (and more realistic-looking than my pics), I don't think it's an adequate substitute. This is especially true for those (like me) who find continuously animated graphics annoying, and have their browsers configured to play them once only. Why not include both still and animated versions? It's not like this article suffers from an overabundance of images :-) -- Wapcaplet 13:39, 28 July 2006 (UTC)
thread_title:  Removed illustrations 

message: I have a request: Someone knowledgeable about engines please write the above two articles. The animated image :Image:4-Stroke-Engine.gif is scheduled to be Wikipedia:Picture of the day on November 4, 2006 and will appear on the Main Page. However, it is against policy to have red links on the Main Page, so you have until then to get these articles written, or at least stubbed. Thanks. howcheng  {chat} 17:01, 4 October 2006 (UTC)
thread_title:  [[Compression stroke]] and [[Exhaust stroke]] 

message: shifted this content added by an anon IP
their are major differences in a two stroke and a four stroke two stroke means that the (for example) dirt bike motor receives power on every turn of the crank shaft creating shorter faster bursts of power. the four stroke receives power on every other turn of the crankshaft creating bigger longer bursts of power. The two stroke has something called a power band which is when the bike hits a certan RPM and explodes with power where a four stroke has all of its power when you need it no wait for a power band.
add it in if it seems to be useful, I couldn't figure where to put it. thanksxC | ☎  08:02, 6 July 2007 (UTC)
thread_title: shifted from article

message: This is big mistake, can not beleive someone can put these two things as one. It looks that diesel engine can not be four stroke.--Billy the lid (talk) 10:05, 16 May 2008 (UTC)
thread_title: Four stroke = Otto

message: dun know?? anybody knows??  —Preceding unsigned comment added by 60.50.78.58 (talk) 07:48, 13 July 2008 (UTC)
replies: text: car go.  NJGW (talk) 17:11, 13 July 2008 (UTC)
thread_title:  effect of usage 4 stroke 

message: Why does the animation not even follow the otto cycle? In fact, why is the Otto cycle (an oscure engineering/thermodynamic representation), a dominating feature of this article? It doesn't represent a single real engine, and is not the only thermodynamic model out there for a four stroke. And no-one except mechanical engineers would be interested, and no-one except mechanical engineers would be enraged by the inaccuracy of it all! Why not just tone down the Otto business and tone up the 4-stroke practical info, applications and what-not? 86.44.202.31 (talk) 22:52, 16 September 2008 (UTC)
replies: text: Why isn't there more information on the otto cycle that redirects to this page? The four stroke cycle redirects here too. The diesel cycle and diesel engine have separate pages. Shouldn't the four stroke engine and four stroke cycle have separate pages also? It is clear these are two separate subjects addressed to those who would expect to find different information in each. 84.44... is one person to indirectly suggest this, I second it.  —Preceding unsigned comment added by 64.56.17.154 (talk) 02:44, 18 October 2008 (UTC)
thread_title:  Bad Article 

message: Not only is this a bad article, but this talk page is full of almost two years worth of whining and complaining by people who aren't doing much of anything to fix the situation. What an awful Talk page this article has. Yeesh.
I am not an expert, but I am wading in anyway attempting to fix the major formatting and layout problems here, and trying to improve it with more general information and cross-article links. (You can blame me for the Otto engine video. I recorded and uploaded it.)
Wikipedia is a collaborative project built by non-experts, and so if people think it's a bad article, you can't do much worse to it by trying to fix it, can you? So please, FIX IT rather than complain about it.
(Please refer to the Wikipedia editing policy page Wikipedia:Be bold for more confidence in your editing skills.)
DMahalko (talk) 01:07, 23 October 2008 (UTC)
thread_title:  I'm not an expert, but I'm editing this article anyway :-) 

message: for a basic article this section is very long with mostly insignificant info .
belongs in racing article maybe
Wdl1961 (talk) 03:20, 4 January 2009 (UTC)
thread_title:   edit Rod/Stroke ratio  

message: see the 28 January 2009 article  revision
Wdl1961 (talk) 22:03, 28 January 2009 (UTC)
thread_title:  Rod/Stroke ratio 

message: I replaced the cleanup box on the page with one highlighting the articles' issues more precisely. I think DMahalko is absolutely right in his comment here. There's no use complaining and then not doing anything about the article, and it's fairly ridiculous that it has gone over 2 years without improvement. Anyway, I'm not an experienced Wikipedia editor, but this is a subject I know at least a little bit about so I'll attempt tackling it when I have the time, maybe late next week. In the mean time, if anyone else has an interest in helping out, or has suggestions, do comment. ɹəəpıɔnı 20:38, 25 February 2009 (UTC)
thread_title:  Highlighted Issues on page 

message: I suggest shifting to  racing article Ierrotpre (talk) 10:21, 22 March 2009 (UTC)
thread_title:   to shift to  racing article  

message: The source [1] given in the very last paragraph for Efficiency and CHP engines is very confusing and not very informative.
A few links i found that explained it much better are 
http://www.toolbase.org/Technology-Inventory/Electrical-Electronics/combined-heat-power
http://www.northeastchp.org/nac/CHP/basics.htm
I'm not confident in my editing abilities to make this change myself  —Preceding unsigned comment added by 75.180.8.80 (talk) 02:45, 23 March 2009 (UTC)
thread_title:  CHP engines 

message: The introductory section ends with "The largest and intermediate size diesel engines are usually two-cycle engines, requiring scavenging air pumps or blowers." Can someone please explain what a scavenging air pump or scavenging blower is please? This piqued my interest because I read the following on the British Rail Class 55 article: "The Class 55's engines were not turbocharged, although they did have scavenging blowers." It would be interesting to learn how a scavenging blower relates to a turbocharger. Thanks!--Rfsmit (talk) 21:17, 3 August 2009 (UTC)
replies: text: Okay, a visit to the Two-stroke engine article cleared that up. The mention of "scavenging" should be removed from this article, given that it only applies to two-stroke motors.--Rfsmit (talk) 21:23, 3 August 2009 (UTC)
replies: text:  No, it's worthwhile noting that because a two stroke isn't a four stroke, they require this extra equipment. There's little between them in terms of thermodynamic cycle, it's just that the four stroke does 4 things in one place over time, the two stroke splits the same things into more than one place, so can use the cylinder for a power stroke in every revolution rather than every second revolution. Nor are all scavenge blowers Roots type. Some are mechanically driven centrifugal blowers, these days most are probably turbochargers. Andy Dingley (talk) 00:32, 4 August 2009 (UTC)
replies: text: if turbocharger it needs  power at startup.  Wdl1961 (talk) 03:53, 4 August 2009 (UTC)
replies: text:  It doesn't need power at startup, it just doesn't spin and so the scavenging is ineffective until the engine starts to turn over under its own power and the turbo can start to spin up. Yes, this does tend to make startup exhaust a bit claggy, until it settles down. Andy Dingley (talk) 10:16, 4 August 2009 (UTC)

text: If you haven't seen one personally, then I'm sure they don't exist. Make sure you speedy delete the Deltic articles then. Andy Dingley (talk) 14:21, 4 August 2009 (UTC)
replies: text:  i hate to admit there are things existing i  have never seen and certainly being build  right now. just fix the article wih the best info, good luck.Wdl1961 (talk) 14:49, 4 August 2009 (UTC)
replies: text:  Why do you think the article is broken and what needs to be fixed? Andy Dingley (talk) 16:33, 4 August 2009 (UTC)
replies: text: both the four and two stroke articles should come to essential points sooner and clearer.the details should come later.Wdl1961 (talk) 18:26, 4 August 2009 (UTC)
thread_title:  Scavenging pump/blower? 

message: ""Efficiency is also intentionally reduced to improve engine reliability and service life, such as with positive crankcase ventilation, which removes moisture from the engine oil by drawing crankcase vapors into the engine intake.""
it would be nice to get a ref with a percentage loss.
Wdl1961 (talk) 04:06, 11 August 2009 (UTC)
replies: text: I agree. You asked for the ref, so you have the motivation. Get to it. ;) -- DMahalko (talk) 05:39, 11 August 2009 (UTC)
replies: text:   i think it is less than +/- 0.1 % Wdl1961 (talk) 12:12, 11 August 2009 (UTC)
thread_title:  removes moisture from the engine oil by drawing crankcase 

message: The reference at the beginning to Otto have any relationship to Beau De Rochas is FALSE.  Otto's work was based on Etienne Lenoir's 1860 Atmospheric Engine. I am removing that reference. I am inserting the factual reference.  Krontach (talk) 05:39, 22 May 2011 (UTC)
thread_title: False Reference

message: Can perhaps the differences between the four stroke motors be explained in particular in regards to power-weight ratio. For example, the Radial engine and Napier Deltic have very high power-weight ratio's
91.182.145.107 (talk) 14:17, 6 November 2011 (UTC)
thread_title: Four-stroke engines with high power-weight ratio

message: The Section numbered 3.1.1 and headed 'Otto Engines' confuses fractional distillation, a purely physical process that separates different molecules without altering them, and cracking, a chemical process that breaks molecules into smaller ones. This is definitely an error. The section also implies that low flash point is always directly connected to low octane number, which I suspect is also an error. 86.152.112.92 (talk) 23:52, 21 October 2012 (UTC)
thread_title:  Confusion 

message: I think the lead section of this article is too big. The part about the description of the stroke could easily be made into a separate section; so could some of the history, it's duplicated bellow anyway.
Aisteco (talk) 18:15, 9 August 2013 (UTC)
thread_title:  Lead section too big 

message: The gif at the top of the page is missing some illustrations. The spark plug fires twice in a 4 stroke engine. Once during power stroke, again during the exhaust stroke. The image only shows the spark igniting during the power stroke. Maybe a side note? 199.19.248.20 (talk) 01:23, 12 April 2016 (UTC)
replies: text: Nope, a 4 stroke engine only requires a single firing of the spark plug at the start of the power stroke. However, many 4 stroke engines add an extra firing during the exhaust stroke to clean-up any unburnt fuel. This helps emissions but is not a strict requirement of the 4 stroke engine. Practically all engines with a distributor (ie typically older than 1990) use single firing.  Stepho  talk  01:46, 12 April 2016 (UTC)
replies: text: Can we include your reply as a side note to the exhaust phase? 199.19.248.20 (talk) 02:16, 12 April 2016 (UTC)
replies: text: Sure. Go for it. Although maybe wait a little (a day?) for others to make suggestions. Stepho  talk  03:11, 12 April 2016 (UTC)
thread_title:  GIF 

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thread_title:  External links modified 

message: I hope,This page is very helpful...plz supporting. Shriya chaturvedi (talk) 12:09, 1 March 2021 (UTC)
thread_title:  Wikipedia 

message: Is it worth including a mention the Humphrey pump? They were in most cases four stroke ICEs, although they were distinct in that they had no pistons, force for imparted directly from the gas to the water, or vice versa. In terms of thermodynamics, they were most similar to Atkinson engines, utilising a variable stroke length. — Preceding unsigned comment added by 81.104.42.30  (talk • contribs) 
:Certainly. That was a type of ICE I had never seen before and I found it interesting.
:Don't forgot to sign your talk page comments with 4 tildes (~~~~) .  Stepho  talk  22:03, 2 May 2021 (UTC)
thread_title:  Humphrey Pumps  

message: — Assignment last updated by Marciadc (talk) 18:02, 24 April 2024 (UTC)
thread_title: Wiki Education assignment: 4A Wikipedia Assignment