Talk:Atkinson cycle

message: An illustration would make this page a lot clearer. (anon user, Aug 23 2005)
Sorry, Carlton Bale! Your edit was not in keeping with the Atkinson cycle heading. The rotary engine has been placed before the four strokes as it more closely conforms to the true Atkinson cycle (one power phase per revolution and different intake/expansion volumes). The original Atkinson engine completed its cycle in one revolution not two revolutions as in a four stroke engine. The different Intake/expansion volumes are achieved by late valve closing in the four stroke engine. This is not really comparable with the original Atkinson design which was based on geometric principles, as is the rotary engine. 
Regards, Sowilo 19:30, 2 November 2006 (UTC)
thread_title: Animation

message: The text of the "Ideal thermodynamic cycle" section and the PV diagram in figure 1 don't agree.  The diagram shows an addition of heat at constant pressure (3-4) that follows the step 2 addition of heat at constant volume (step 2a?).  Step 4, the rejection of heat at constant pressure is clearly a rejection of heat at constant volume (5-6) in the diagram.  Lastly, there's a reduction of volume at constant pressure (6-1) in the diagram that's not reflected in the text.
Unfortunately, I don't know how an Atkinson engine works (that's why I was looking here!), so I don't know whether it's the text or the diagram that's in error.
ExDonH (talk) 16:21, 18 September 2008 (UTC)
replies: text: I believe the diagram is wrong. However, it is possible that two different cycles might be called "Atkinson" or possibly the diagram is of what is called the "Atkinson-Diesel" cycle. I am looking into this but am rather on the boundary of my knowledge. Expert advice very much appreciated! Thincat (talk) 13:50, 9 January 2009 (UTC)
thread_title:  Text and diagram don't agree 

message: Clarified to model year, production year can be the same leading to confusion.  —Preceding unsigned comment added by Jappahut (talk • contribs) 18:52, 29 October 2009 (UTC)
replies: text: Since we have the standard dilemma of US vs the rest of the world and the years are not particularly important in this article, I figure it's easier to simply delete the years. All these particular models are current models anyway. Cheers.  Stepho  (talk) 22:23, 29 October 2009 (UTC)
replies: text: Hmmm... according to this CNet article, the 2019 Honda Insight hybrid will use an Atkinson engine to run its generator (to charge the Li-Ion battery pack and power the front drive motors) AND have the ability to latch up directly to the front drive axles, but the previous version[s] of the Insight did not use an Atkinson engine. I don't see how dropping the model year/s is going to continue working in that section. Darr247 (talk) 19:37, 21 June 2018 (UTC)
replies: text: You do realise you are responding to a thread 9 years old? Also, the 2019 model year Insight has not been released yet, so it cannot go in a list of production cars. When it is released we can add it and update the 'as of' date.  Stepho  talk  22:00, 21 June 2018 (UTC)
thread_title: Production year

message: Both this one and the article about the Miller cycle are filled with assumptions, spin-off examples, an half-trues.
Miller cycle/engine: It should be possible to find proper references (patent by Ralph Miller?). To my knewledge, this uses altered valve timing to achive a difference between compression and expansion ratio of a 4-stroke engine. This type/technical solution is the one several engine manufacturers use today (the listed examples) to get either reduced compression ratio (knock preventing, boosted engines), or increased expansion ratio (efficiency, naturally aspirated engines e.g. the engine used in later Toyota Prius cars ).
Atkinson (much older) used a special crank mechanism that also gave such difference. Side effect of this mechanism: 1 cycle <=> 1 crankshaft revolution <=> 4 piston strokes. To my knewledge, no mfg use this one, despite that they say that they do (Toyota?).  
Is'nt there some student, or anyone else, that have time and can gain some credit for it, to do some research and rewrite these articles?  — Preceding unsigned comment added by 193.12.111.194 (talk) 14:10, 10 October 2011 (UTC)
thread_title:  Could be better 

message: The Rotary Atkinson cycle engine is a very interesting topic in its own right. Its also complex; what is described and explained here appears to be just the tip of an iceberg. It should be expanded into its own article, Rotary Atkinson cycle engine. I've temporarily redirected that page to Atkinson cycle#Rotary Atkinson cycle engine. —James Haigh (talk) 2013-03-13T02:23:17Z  —Preceding undated comment added 02:23, 13 March 2013 (UTC)
replies: text: If you have information then please do add it. You can add it to this article for the moment. If it gets to be more than a handful of paragraphs, then we can split it into its own article. But beware not to just duplicate large bits of the Otto cycle rotary article - ie we only need the bits that are different to the Otto cycle rotary. Cheers.  Stepho  talk  08:19, 13 March 2013 (UTC)
thread_title:  Rotary Atkinson cycle engine: Expand as a main article 

message: I've put in a new section on this, and I've described its operation with a word picture, also giving a book reference. However, the section should really have a proper diagram showing the Atkinson differential engine's internal workings, but the only images I've found so far have been for the engine's external appearance, e.g. at http://www.pbase.com/captain_carl/image/86215717 and http://www.pbase.com/captain_carl/image/86215675, and I don't know their copyright status anyway. Can someone who knows how to do it work up my description, those images, and maybe material from the book reference I gave into proper graphics for this section, ideally an animated gif? Thanks in advance. PMLawrence (talk) 11:18, 30 May 2014 (UTC)
thread_title:  Atkinson differential engine - diagram request 

message: About mid away through the first paragraph in thE section on the modern Atkinson, the following sentence appears (w/ no reference provided);
.
'...when this occurs, all the available energy has been obtained from the combustion process...'
.
This statement suggests naive ignorance of the laws of thermodynamics and their strict enforcement, or a calous wanton defiance.
Either way, suggesting all the available energy has been removed mean the exhaust was no warmer than ambient, and that a pump would need to add energy back to enable flow out the tailpipe.
166.173.248.167 (talk) 10:20, 15 October 2015 (UTC)
thread_title:  Change needed in'Modern Atkinson Engine Cycle, section. 

message: I've seen some sources say that Atkinson cycle engines have comparatively poor low end torque.  There's no mention of torque in this article (odd for an engine article).  Any reason to doubt these sources?  --Juventas (talk) 01:55, 7 June 2017 (UTC)
thread_title:  Torque? 

message: This article and related articles make multiple statements along the lines of "The Atkinson cycle is designed to provide efficiency at the expense of power density." Can some comparative numbers be provided here or elsewhere? Thanks.  — Preceding unsigned comment added by 23.29.213.104 (talk) 21:20, 22 October 2019 (UTC)
replies: text: The nature of an open wiki is that if you can find those numbers then you can add them yourself. We can help you with the formatting side.  Stepho  talk  22:19, 22 October 2019 (UTC)
thread_title:  Can actual efficiency numbers be provided?