Talk:Wankel engine

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Wankel engine is a former featured article candidate. Please view the links under Article milestones below to see why the nomination failed. For older candidates, please check the archive.
February 25, 2005 Featured article candidate Not promoted

I came to this page to state that the wankel uses the Otto cycle but I see someone beat me to it. I agree completely with the comment below. The offending line should be changed to "lower than that of more common piston engines" or something. I don't know enough about their relative efficiencies to make it myself. —Preceding unsigned comment added by 68.52.34.198 (talk) 22:00, 10 November 2007 (UTC)

Hi, i would also like to point out what to me seems to be a mistake. I'm refering to the paragraph in the disadvantages section where the fuel efficiency of the wankel engine is rated as lower that that of the "otto cycle" engine.. As far as i know, despite being a different design than most otto cycle engines witch use pistons, the wankel engine is still an otto engine, as it has the same four strokes (intake, compression, ignition exhaust) as any other otto engine. therefore i sugest replacing the term otto engine with piston engine, or maybe reciprocating engine

Contents

[edit] Country of Origin

This article and the article on the inventor disagree on his country of origin. —Preceding unsigned comment added by Fountainmon (talk • contribs) 08:48, 2 September 2007 (UTC)

[edit] soviet wankel

soviets also produced rotary/wankel engines, look up Vaz 311. as its pretty bizarre, it should be mentioned :) http://cp_www.tripod.com/rotary/pg07.htm Savuporo 20:01, 11 April 2007 (UTC)

[edit] Racing

Racing section has turned into Mazda racing, and I'll get around to moving most of it there pretty soon. Gzuckier 18:44, 8 Mar 2005 (UTC)


The RX-8 has not yet been launched, it is supposed to be released May or June 2003, as a 2004 model, the article states it came out in 2002.

rotarygod.com


Never mind, it turns out that http://encyclopedia.thefreedictionary.com/Wankel%20engine was taken from wikipedia. Some of the technical stuff here was just wrong.Gzuckier 18:43, 20 Jul 2004 (UTC)

Yeah, gotta watch for the attribution in ultra-tiny print at the bottom of the page. TimothyPilgrim 01:34, Jul 21, 2004 (UTC)

[edit] Animation

I ran across a public-domain animation of the rotor (not the cycle) on the German Wikipedia, and stuck it in the commons: Image:Wankel_anim.gif. It's illustrative, but is really driving me batty.

Any thoughts on whether or not it should be included? --Milkmandan 06:17, 2005 Mar 8 (UTC)

I'm not sure it's technically correct. Apart from the intrusion of the rotor on the trochoid, the eccentric shaft rotation seems wrong... --SFoskett 13:18, Mar 8, 2005 (UTC)
Pretty, but like you said, seems just wrong. Gzuckier 18:46, 8 Mar 2005 (UTC)
I agree, it doesn't look correct to me either, I work on rotary engines.
The animation mentioned above contains a big mistake. The inner cogwheel is attached to the central shaft and does not orbit excentrically. Wikirud 03:51, 2006 Oct 20 (UTC)

[edit] Animation Owner Question

I am sure the centre shaft is rotating the wrong way on the animation, I am sure it rotates in the opposite direction to the apex. please correct me if I am wrong. Rapidlaser 15:17, 10 May 2007 (UTC)


Hi, I'm the administrator for Rotary Engine Illustrated. http://www.rotaryengineillustrated.com, I'd like to post some of my animations, that I own outright and put them on the website but not make them avaliable for anyone to download. Can I do this?

please contact me at kazisdaman2@hotmail.com, if I can share the animations with wikipedia. —Preceding unsigned comment added by 24.22.98.127 (talk • contribs)

(From WP:C) If you contribute material to Wikipedia, you thereby license it to the public under the GNU Free Documentation License. If you own the copyright to the material, you retain copyright to your materials. You can later republish and relicense them in any way you like. However, you can never retract the GFDL license for the versions you placed here: that material will remain under GFDL forever. --Van helsing 14:13, 13 October 2006 (UTC)
Ironic… you don’t want to make your animations available for download on wiki, but are happy to download them from wiki [1] without giving credit to wiki or User:Y_tambe who made it. Do you now also outright own this animation? --Van helsing 14:21, 20 October 2006 (UTC)
I believe my esteemed colleague above is saying "under the GFDL, you must attribute the source of material copied from Wikipedia. You are absolutely welcome to use Wikipedia content, but you really must mention where it came from". - CHAIRBOY (☎) 14:33, 20 October 2006 (UTC)

[edit] Monty Python reference

I'm surprised there isn't a reference to the Monty Python sketch "Are You Embarassed Easily?" I'm sure many geeks (non-gearhead geeks, that is) are familiar with this only as a reference in the sketch.

[edit] Neutral POV?

I'm not sure the "Note about emissions & fuel consumption" really meets the neutral point-of-view standard. It seems to be stuck in there without really adding information, run against conventional wisdom and is a clearly pro-rotary viewpoint. It's argumentative, not informative. 207.171.180.101 17:10, 19 April 2006 (UTC)

--Actually, it's both argumentative and informative at the same time. It needs to be cleaned up a little, but it is quite true; you cannot compare a RENESIS motor's fuel consumption with either a pistoned engine of the same displacement or a pistoned engine designed for economical operation. A 1.3 litre Wankel is best compared to a 2.6 litre performance piston engine in terms of fuel economy. Also, fuel economy is directly related to how you drive; high power 13B turbocharged motors can pull 30 mpg if driven carefully, while you can get less than 5 mpg if you beat on a RENESIS.

  • I've re-written that section; it read like RX-7 cheerleading. Though the fundamental claim was sound. I did remove the following claim, since it had no source:

    The rotary engine does not suffer with higher emissions or poor fuel consumption, in fact with fair comparisons the rotary engine in many cases can be superior to the piston engine for both emissions and fuel consumtion.

    It might be true. I'm quite sure that if you turbocharged a 1.3 piston engine and boosted the power output to 230BHP you'd be looking at GPM, not MPG (smile). But I don't know of any factory-fitted engines that fit the bill, so there's no way the claim can be verified. --Collard 11:40, 24 April 2006 (UTC)
I'm not sure the re-write is better, but I left it. I did remove the statement that the rx-8 is turbo'd, which it isn't. SchmuckyTheCat 14:25, 24 April 2006 (UTC)

Is here the File X Meeting?

image:EA871ETA.gif

This is not better nor poorer as a gasoline piston engine. Effencies for a gasoline piston engine 25~35%!

"A typical production two-rotor Wankel engine does not utilise a bearing between the two rotors, allowing a one-piece eccentric shaft to be used. This tradeoff allows for cheaper manufacture at the expense of peak engine rpm, due to eccentric shaft flex." ouh

The forces extinguish themselves, therefor need a two rotor Wankel no bearing between the rotors. No forces no bearing, a useles bearing is money wasting!

"In engines having more than two rotors, or two rotor race engines intended for high-rpm use, a multi-piece eccentric shaft must be used, allowing additional bearings between rotors. While this approach does increase the complexity of the eccentric shaft design, it has been used successfully in the Mazda's production three-rotor 20B-REW engine, as well as many low volume production race engines." that is not true. The C-111-2 4 Rotor Mercedes Benz eccentric shaft for the KE Serie 70, Typ DB M950 KE409 is made in one piece!

Historie

  • Felix Wankel invented 5 March 1954 the Turning piston engine DKM 54.

1957 converted the NSU ingenieur Hanns Dieter Paschke the DKM54 to the rotary piston engine KKM 57P. --80.226.208.196 21:35, 2 July 2006 (UTC)

  • Modern Wankels such as the Renesis found in the RX8 burn a small quantity of oil by design; it is metered into the combustion chamber in order to preserve the rotor tips. Owners must periodically add small amounts of oil, "slightly increasing running costs".*

I feel this should end after oil with a period. The "slighly incresing running costs" feels tacked on and not so neutral.

And reciprocating piston engines does not use oil? For reciprocating piston engines is a oilconsumption of 1L/1000km normally and you must change the entire quantity of oil. --90.187.119.245 22:27, 28 August 2007 (UTC)

[edit] Advantages

"This feature also led to a great deal of interest in the Soviet Union, where high octane gasoline was rare." Soviet Union doesn't exists from 1991... Probably change this to Russian Federation?

  • Perhaps the interest was in the past, given that the claim is written as past-tense? Belltower 19:21, 13 November 2006 (UTC)

One another topic, one approach to improve fuel efficiency has been to shut off the engine at idle time, or shut off part of it when lower power is needed. Another approach is to run the engine at its peak efficiency, charging a battery. Is the rotary engine particularly well- or ill-suited to any of these measures? I couldn't find any references. Belltower 19:21, 13 November 2006 (UTC)

The article contains advantages and disadvantages of the RCE design. These categories are not included in entries for 2 and 4 stroke engines. This seems to imply some sort of inherent design flaw with the Wankel. To give a more balance view and for the sake of consistency I feel this section should be rewritten. Cajun1958 23:27, 18 December 2006 (UTC)

[edit] VW seat belt pretensioner system?

Perhaps the most exotic use of the Wankel design is in the seat belt pretensioner system of the Volkswagen New Beetle. In this car, when deceleration sensors sense a potential crash, small explosive cartridges are triggered electrically and the resulting pressurized gas feeds into tiny Wankel engines which rotate to take up the slack in the seat belt systems, anchoring the driver and passengers firmly in the seat before any collision.

I question the accuracy of this statement. I think I found the patent in question -- http://www.patentstorm.us/patents/5485970-description.html -- which reads :

The motor 40 is not an internal combustion motor, although it is similar in construction to the known "Wankel" engine.

... so I'm not sure if being similar to a wankel engine is enough to call it a wankel engine. Yes, the picture certainly *looks* like one, but is that enough? (Oh, here's a link to the patent that includes a picture -- http://www.google.com/patents?vid=USPAT5485970&id=N6QhAAAAEBAJ&dq=5485970 --= which does look very much like a wankel engine.) dougmc 23:47, 24 January 2007 (UTC)

Well, it describes it as
a rotary trochoidal motor comprising a housing having a wall with an inner surface defining a chamber, a rotor rotatable in said chamber and having a fluid engagement surface, an output shaft supported for rotation relative to said housing, and means for transmitting rotational force from said rotor to said output shaft to rotate said output shaft;
If that (along with the pic) don't describe a Wankel motor.... In fact, it wouldn't hurt to use that as the definition in this article. Gzuckier 15:11, 11 April 2007 (UTC)

[edit] license today?

"Curtis-Wright takes 50% of the license income made in the USA and limited its development activity to a minimum." How could this be. Didn't the patent rights run out years ago? --Gbleem 09:35, 27 January 2007 (UTC)

  • Great Question. I agree and would love to see a subject-matter-expert provide some insight and updates. -- ViaBest 18:07, 1 February 2007 (UTC)

When a patent expire than need you no license.--90.187.41.54 12:28, 28 March 2007 (UTC)

[edit] Disadvanatages?

The page contains an advanatages section, i was just wondering if there are any disadvantages to the engine? Zephyr 12:30, 1 February 2007 (UTC)

Sure. Wankel engines have traditionally consumed a little more fuel, though that gap has been closing over the years. Errm, I think there are some slightly higher emissions because of the oil they consume at combustion for lubrication. Dunno if there's enough there to be of use in the article, and it'd need sourcing of course. - CHAIRBOY (☎) 13:37, 1 February 2007 (UTC)
Well, having an advantages section without a disadvantages section seems very bizarre, especially as the article then goes on to describe how wankels aren't used for many road cars, and how this number has been decreasing to the point where only one is available (and that's a sports car anyway) Modest Genius talk 15:54, 1 February 2007 (UTC)
Based on grounds of increased fuel consumption, I feel a Disadvantages section is warranted. I don't feel I am qualified enough in the subject to break the ground, but I think there is enough support to start a Disadvantages section even if it start with a lacking "increased fuel consumption" statement. -- ViaBest 18:11, 1 February 2007 (UTC)

Under "Pistonless rotary engine" there is a discussion of the disadvantages - primarily sealing problems, perhaps that could be incorporated here, or the pages could be merged.

What is the weakness? The only wankel engine who has problems with the apex seals is the NSU Ro80. Constructional defect, wrong material choice and unsatisfactory testing.

"Worse still, these two sets of seals must somehow join at sharp corners at the ends of the apex seals. " Yeah, therefor invented Felix Wankel the Sealing pin.

"An additional problem is that the seals at the Wankel rotor apexes meet the chamber walls at an angle that varies plus and minus ~26 deg; during the cycle, while a piston ring meets the cylinder walls at a constant angle.

That is probably the largest imbecility. First, without varies angels work no apex seal. This is a function of the k-factor and the aequidistante.

As well as making the seal design itself more difficult, this means that while multiple rings are easily fitted to a piston, a corresponding approach is impossible with the Wankel apex seals.

Completely wrong.

"Another disadvantage of the Wankel engine in particular is the large surface area of the combustion chamber which reperesents a large heat transfer and quench area, combined with an unfavorably long and rather thin stretched combustion space, which means a long flame travel. The combustion is less complete than in, for example, an RPE, which has a more compact chamber shape with smaller area per unit of chamber volume. The Quasiturbine has similar disadvantages with its concave combustion chamber, and in the AC design the sharp angles of the carriers hamper the propagation of the flame front, leading to incomplete combustion"

The geratest myth for ever: The large surface area. An Wankel with a camber volumen of 1,3ltr has a displacment of 2,6ltr. But I have only the losses as 1,3ltr engine. And completely different heat transfer and isolating oil film. Therfore need a Wankel a smaller cooler per kW engine power!!!--90.186.119.176 22:39, 29 March 2007 (UTC)--90.186.119.176 22:38, 29 March 2007 (UTC)

I don't know who wrote the latest disadvantages section, but it was utterly incomprehensible. Due to that reason (it was doing more harm than good to the article, in my opinion), I tried to clean up the grammar and structure a bit, whilst retaining the salient points. Some of the deep technical detail was lost, but if anyone wants to try and explain some of the disadvantages to that level of detail, they should really try to make sure the explanation is excellent. (Sev, 10 Apr 07)

Then should you make correct and not wrong statements. A Four stroke exaust has only 180° opening time!! For a Wankel engine 270° this is 50% more opening time! Four stroke reciprocating engine 720° (2 rotations or 4 x 180° ) for a complet Otto cycle. A Wankel engine 1080° (3 rotations or 4 x 270°) per flank for a complet Otto cycle and this at the same time for 3 flanks. The intake time is 50% longer for Wankel and not shorter. A wankel engine can suck in therefore more air! The only problem you can't pre-store the mixture! Why? No valves!!! The exaust time is 50% longer for a Wankel engine and not shorter! Then I would see this comparison natural aspirated four stroke engine with 1,3ltr displacement and 238HP! To compare combustion engines needs we the specific fuelconsumption and not MPG or hypothetical four stroke reciprocating engines!!!--90.186.252.183 08:51, 11 April 2007 (UTC)

Well, I guess that shows how much sense the previous description made :P Personally, I think talking about ° of opening time for the intake valves is well beyond the scope of this article, and beyond the interest of most. However, a third opinion would be appreciated on this. (Sev, 11 Apr 07)


Even after Sev's grammatical corrections this section is still incomprehensible. The intelligible parts send mixed messages at best; the uncited claim that the Wankel's engine is less efficient in general conflicts with Mazda's results. 206.55.189.90 (talk) 05:10, 17 March 2008 (UTC)

[edit] Materials

There is some questionable content in the Materials section: "We used water in a radial or axial cooling system, with the hot water from the hot bow we heated the cold bow. Therefore the thermal expansion remains tolerable." This is either copyvio or original research. meatmanek 23:19, 8 April 2007 (UTC)

In the 60's called we this know-how! I Recommend Richard F. Ansdale S. 127, der Wankelmotor Konstruktion und Wirkungsweise or Wolf Dieter Benzingers Rotary Engines or Kenichi Yamamoto Rotary Engine S.32. --90.187.208.16 17:57, 10 April 2007 (UTC)

Image:Ch_Ru_Exzenter.jpg

[edit] Wankel engine future

What about adding a section on future prospects like the H2RE engine? Here is a link to Mazda's Hydrogen Rotary Links Page http://www.mazda.com/mazdaspirit/rotary/hre/index.html

[edit] the inventor

There seems to be a mistake on who invented the rotary engine. The engine was actually invented in 1904 by Margaret Knight, who was also the inventor of the paper-bag making machine.

No, that's the other rotary engine. Maury 23:43, 27 August 2007 (UTC)

[edit] Diesel

Not much is mentioned about using diesel wankel engines. Does the generally low compression ratio make wankels unviable modern vehicles? Should it be mentioned if that's true? Scott Paeth 03:07, 22 August 2007 (UTC)

[edit] Specific power

"Wankel engines have several major advantages over reciprocating piston designs, in addition to having higher output for similar displacement and physical size"

I've heard, in both aviation and automotive articles, that the Wankel can be characterized as having "one third less power, but one half the weight". The statement above suggests otherwise. Can someone explain why the specific power is higher, and perhaps give a characterization like the one I had heard before?

Maury —Preceding unsigned comment added by Maury Markowitz (talk • contribs) 12:38, August 27, 2007 (UTC)

How these articles come to that conclusion is unclear. The power-per-displacement and power-per-weight ratios are incredibly high (check the List of automotive superlatives). I imagine that they must be confusing applications of the engine with properties of them? Mazda's wankel engines are all relatively small and light compared to other sports car engines that have more power at disproportionate weight and size gains, could this be the basis of those statements? Scott Paeth 22:53, 4 September 2007 (UTC)

[edit] Low Octane Hydrogen car?

From the article:

...thereby allowing the use of fuel of very low octane number or very low ignition power requirement without preignition or detonation, a particular advantage for hydrogen car.

Octane rating lists Hydrogen as a 130 Octane rating. So, one or the other is like incorrect? --Puellanivis 00:55, 23 October 2007 (UTC)

Octan rating for Hydrogen is ~50 Octane! --HDP 18:33, 14 November 2007 (UTC)

[edit] Exotic Uses / Seatbelt Pretensioner

I'm new to Wikipedia, so I won't dare edit. However, after reading that the Volkswagen New Beetle's seat belt pretensioner included a type of wankel motor, I went to a VW salvage and got a used unit from a crashed Beetle. I totally disassembled it, and there is nothing Wankel about it. It is definitely the common "ball and sprocket" type of pretensioner. I suggest the reference to the VW New Beetle be removed or references cited.Dustyattic (talk) 15:26, 30 December 2007 (UTC)

Front or rear? Audi and VW use this seat belt pretensioner only in the front.--HDP (talk) 13:02, 1 January 2008 (UTC)

It's mentioned again in the Feb 2008 Automobile magazine: A Wankel seatbelt tensioner in Volkswagens and Mercedes, powered by expanding gas and capable of three rotations. Gzuckier (talk) 18:04, 10 January 2008 (UTC)

[edit] Animation Off

The animation of the rotary engine has the firing sequence off, it doesn't fire both spark plugs at the same time.


Here is a correction of the animation on how it really fires:

[[2]http://www.rotaryengineillustrated.com/wankel-engine-animations/engine-strokes-animation-2.html]

Not really, the Marine Ro135, Mazda Racing Wankel and Rensis fires simultan both spark blubes, this lowers the fuelconsumption. Then fires L before T on a 13BT and 13b-REW only for reasons of exhaust gas emission (lower HC), with the handicap of a higher fuelconsumption. 13B fires L two times (Wastespark) at the 13BT and 13B-REW.--HDP (talk) 16:00, 16 March 2008 (UTC)