Talk:Engine balance

message: From the opening paragraph: "... as well as reducing the stress on other machinery and people near the engine." People near the engine? Is that intentional? What is that supposed to mean? BK DC (talk) 02:44, 1 January 2009 (UTC)
thread_title:  "People near the engine"? 

message: While in F1-cars, and many motor cycles the engine is a part of the frame,
in cars for road usage the engine sits within its own suspension.
Source:
Neuer Ottomotor mit
Direkteinspritzung und Doppelaufladung
von Volkswagen
Teil 1: Konstruktive Gestaltung
in
MTZ 11/2005 Jahrgang 66
contents:
Crankshaft housing weights: 29kg  (for inline-4)
Cylinder header: ?
Crankshaft: ?
Piston weight: 288
connecting rod: ?
That means: In a free floating engine with a single piston and 80 mm stroke the piston moves about 76mm and the engine block moves 4mm every stroke.
Source:
Die Entwicklung von
Massenausgleichseinrichtungen
für Pkw-Motoren
in
MTZ 5/2003 Jahrgang 64
contents:
says second order forces are 1/3 of first order forces (and moments for that matter).
In an inline-3 engine the first cylinder moves 3mm up while the last cylinder moves down 3mm.
In an inline-5 engine the first cylinder moves 1mm up while the last cylinder moves down 1mm.
Source:
Baustein
Grundlagen Motorentechnik
by
BMW
contents:
Forces on piston due to pressure in cylinder: 68.000N  !
speed of piston: up to 32m/s at 700/6 Hz  =>  23457 m/s/s  => 7000 N force on connecting rod
Porsche Boxster:
Engine (flat-6) is mounted at three points
BMW on the topic why they do not built an V12 in the oil crisis:
energy smoothness needs at least 6 cylinders
Sources needed:
* Any friction in the mount reduces engine power / costs fuel.
* V6 and V10 engine are mounted in a gimbal so that they can rotate freely.
* The VW beetle has a flying arm in his flat-4 and the cross plane V8 compensate a lot of the imbalance at every crank, but in most engines the crankshaft is much too light to balance each crank individually and instead only the whole engine-block is balanced.
Arnero (talk) 11:41, 15 March 2009 (UTC)
thread_title:  Engine mount 

message: Looking at the firing order at their web page and comparing it with the 4 possible firing orders of the cross-plane 90° V8,
it seems that the W16 is composed of two V8 (with different firing orders) rotated by 15° (with respect to each other) and shifted by half the cylinder pitch.
And some swiss guy said, it has no first order imbalance. This may mean that the two cross-plane V8 compensate their first order imbalance and
no heavy crankshaft is needed.
Thus in contrast to VR6, W8, W12 it has good balance.
The VR8 by AlfaRomeo may also have a good balance. Do we mention inline-8 ?
Arnero (talk) 12:02, 15 March 2009 (UTC)
thread_title:  Bugatti W16  (and other W and VR) 

message: I am reading this thread to get a better insight on engine balancing.
As I have a engine that I would like to get balanced. The information that I have on my four cylinder engine stress the fact its got a Balanced crank shaft as standard. It is a peugeot ew12j4 petrol engine tuned to deliver its power as a deisel would. 80% Torque from 2000 rpm 
I was looking for an answer to the question " would having the pistons and conrods lightened and balanced futher would this cause further imbalance of the engine due to the crankshaft being specially balanced?"
I not 100% sure Im allowed to asked these questios. If you dont ask you dont get.  —Preceding unsigned comment added by S.phillips1988 (talk • contribs) 02:23, 24 May 2009 (UTC)
replies: text: All first world car engines have balanced cranks as standard. Not many are balanced as running engines, as such, so so long as your pistons and conrods were still a balanced set you are unlikely to make things worse. By that I mean that all 4 pistons, should weigh the same, likewise the conrods. Normally when you balance a running engine you are correcting for the centring of the flywheel on the crank, nothing to do with the reciprocating components. Greglocock (talk) 04:15, 24 May 2009 (UTC)
thread_title:  Confusion of subject gone too far. 

message: Nothing in this article about rotary engines (e.g. jet engine, turbine, wankle engine etc.)  As article is titled 'Engine balance' I think types of engine other than just reciprocating ones should at least be mentioned.  I'm not an expert enough on engines to start a new section, but know enough that these engines have some big advantages in terms of balancing.  —Preceding unsigned comment added by 86.181.34.88 (talk) 15:31, 6 February 2010 (UTC)
thread_title:  Rotary engines 

message: The statement that only straight six and flat six engines (and V12 which is two straight 6 ??) can be balanced seems very suspect - eg I see no difference between straight 6 and straight 4 in this respect, also what about boxer and opposed piston engines - it seems that if straight 6 can be balanced then all these other can be.. That is only my opinion + my unverified calculations.
To fix the facts (whatever they are) need to be checked, and referenced by truly reliable sources (ie those which mathematically demonstrate the truth of their statements).
The article also has issues with needing cleanup, references, and possibly containing WP:OR - which may also related to the claims about balance. It also omits other engine types ( see sections above - rotary etc)Imgaril (talk) 19:08, 29 August 2011 (UTC)
thread_title: Accuracy dispute /  multiple issues

message: http://en.wikipedia.org/w/index.php?title=Engine_balance&diff=496267331&oldid=496192903
(please ignore my previous garbled edit summary  if it doesn't help.
a. I attempted to simplify the textual description of the secondary (2nd harmonic) motions. Ultimately though it is nearly pointless - it needs diagrams and a mathematical derivation, (and a source). See also :pt:Equilíbrio_de_motores_de_combustão_interna - this is part of what is needed here. This text shouldn't be in this section anyway - it should have all been explained in the earlier section Engine_balance#Primary_and_secondary_balance
b.the claim that "In general in a single cylinder engine it is not desirable to balance the weight of the piston and connecting rod 100% as large secondary vibrations are then produced.  Often a "balance factor" of about 60 to 70 percent of the reciprocating mass will be chosen"
I'd like to see a reference for this. I understand that the in-cylinder-motion-axis vibrational motions cannot be 100% balanced by crankweights. I assume that the sentence refers to some attempt to minimise vibrations taking this into account. 60% sounds low to me. Needs WP:VERIFY.Oranjblud (talk) 12:59, 6 June 2012 (UTC)
replies: text: I decided to totally remove this - reasons:
*Adding balance weights does not cause any "secondary motions" - poorly written
*Learn to walk before running. There article barely wipes it own arse. I will remove all the dubious parts. fed up of looking at poorly written unreference stuff that nobody is going to fix. Oranjblud (talk) 14:11, 6 June 2012 (UTC)
thread_title: Single cylinder

message: Looks good. I would like to see a mention of balance factor. "In general in a single cylinder engine it is not desirable to balance the weight of the piston and connecting rod 100% as large secondary vibrations are then produced.  Often a "balance factor" of about 60 to 70 percent of the reciprocating mass will be chosen" is true enough, but  all practical high speed conventional engines use the crank webs to compensate in important ways for the reciprocating masses. That 60% number is not too bad as a first stab. Greglocock (talk) 06:34, 7 June 2012 (UTC)
thread_title: Rewrite 6/6/12

message: I am loathe to merely revert this, and yet there are many faults with it, of both style, as a wiki article, and content. Someof it is frankly nonsense, and some is misleading, and doubtless some is good. That being said the previous version was by no means a paragon. So, please could interested parties comment below as to whether to use the new rewrite as a basis for much further work, or should we try and improve the old version? Greglocock (talk) 05:25, 29 October 2013 (UTC)
replies: text: Could you start by pointing out what parts are nonsense and what are misleading?  That would form a basis for this discussion and would give me a chance to improve. Yiba (talk) 05:42, 29 October 2013 (UTC)
replies: text:  I'm not going to comment in detail on the new article since I suspect that there is an even chance that the old version is what we'll go back to. The question here is what do we use as a basis, not how do we improve whichever is used as a basis. Greglocock (talk) 05:55, 29 October 2013 (UTC)
replies: text: Use the new rewrite as a basis for much further work.  Abandon the old version.  I'll go over both a few more times and add info from the old version, to this, as I see needed.  I'm also going to add expansion needed tags to this new version.  --Dana60Cummins (talk) 15:15, 29 October 2013 (UTC)
replies: text: Fine by me, I suggest we leave it for two days, say end of October, just in case somebody comes up with a preference for the old one. Greglocock (talk) 22:30, 29 October 2013 (UTC)
replies: text: Right and yes.  I'll leave it alone until November to keep things simple.  Although Yiba could edit.--Dana60Cummins (talk) 22:40, 29 October 2013 (UTC)

text: Also writing that is readable by a lay audience! This is a hard topic and not generally well understood, even after reading most textbooks. We need an article that our readers can understand and learn something from: most of the standard texts fail this and are very hard going. Andy Dingley (talk) 11:10, 31 October 2013 (UTC)
replies: text:  What sticks out to me the most is the new Primary and secondary balance bit.  As the old version really doesn't cover it like the new essay style here.  In the event of a revert that bit will get shoehorned in the old.  It is covered better than any of my books in college covered the subject.
The old version: 
Secondary harmonics can be balanced in some multi-cylinder engines by appropriate selection of the phase of motion of individual cylinders. For example, flat-eight engines with an appropriate configuration can eliminate all primary and secondary balance problems, without the use of balancing shafts
Compare to the new one and the difference is obvious.  I am alarmed that editors would blindly try to revert this.--Dana60Cummins (talk) 15:11, 31 October 2013 (UTC)
thread_title:  Massive rewrite October 2013 

message: Is the text "acceleration of change in the position" in the article accurate? This reads as a third order derivative (i.e. jerk), when perhaps a second order one was intended? Should it actually read "acceleration of position", or simply "acceleration"?
:"Acceleration of change in the position" is accurate.  A position does/can not accelerate, so "acceleration of position" is incorrect.  A simple "acceleration" does not describe what accelerates, so it is ambiguous.  Please sign your comments, PerryTachett Yiba (talk | contribs) 01:49, 8 July 2014 (UTC)
replies: text: Come to think of it, "Acceleration in speed of change of position" may be more accurate, but is bad English.  If anyone can come up with a better alternative, I will be all ears. Yiba (talk | contribs) 01:56, 8 July 2014 (UTC)
replies: text:  So far as i can tell "Acceleration in speed of change of position" is d^2/dt^2 d/dt dx, which is d^3x/dt^3 which is jerk. I have not read the relevant part of the article, i doubt the 3rd derivative has much to do with balance. Greglocock (talk) 02:52, 8 July 2014 (UTC)
replies: text: Are you PerryTachett, 178.128.192.226, or Greglocock?  I'd appreciate if you could read the entire Secondary vibration and come back to me.  Yiba (talk | contribs) 04:00, 8 July 2014 (UTC)
replies: text: i am Greglocock (talk) 05:04, 8 July 2014 (UTC)
replies: text: I am open to suggestions on how to make the section less confusing, more correct, and less lecture-sounding.  "Acceleration in speed of change in piston and smallend up/down position" can be expressed as d^2 x/dt^2 (see Piston motion equations#Acceleration 2).  However, the equation I am using on this article just describes the "change in piston up/down position" part only, in order to make it simpler and easier to understand for people who are not familiar with methematical analysis.  For those who are familiar, it might make it a bit confusing if it is taken to mean "Acceleration in speed of change in piston up/down position".  But these people are exceptions, and they can normally see the difference between the two, and the reason for using the simpler equation that takes time domain out of the equation.  I would appreciate any suggestion to improve the current article.  Yiba (talk | contribs) 06:40, 8 July 2014 (UTC)
replies: text: Thanks to Greglocock's comments, I re-examined the equation I used and realized I over-simplified it.  So I made a correction.  I considered adding the discussion on d^2 x/dt^2 (Acceleration in speed of change in smallend up/down position), however, I opted against it as it seems to add little for the understanding of this non-sinusoidal motion by people who are not used to methematical analysis.  I owe this spotting the mistake to Greglocock.  Thank you.  Yiba (talk | contribs) 02:23, 15 July 2014 (UTC)
thread_title:  Acceleration of change of position? 

message: Thank you for your attention to this article.  I reverted your three edits for the following reasons:
1. "apart from the first, only even numbered orders exist" in this case is wrong.  The article talks about vibrations with frequencies of three, four and five times in a crank rotation, and when #1 and #2 cylinders in an inline six together have similar compression or combustion imbalance, it appears once in two rotation for each, or once in a rotation of crankshaft.  If the spacing between #1 and #2 cylinders is 360 degrees, then it might result in a sinusoidal wave with the frequency of once in a rotation, but since the spacing is 120 degrees, this does not happen.  Instead, one component of the resultant vibration ends up having the frequency of three times (360/120=3) in one crank rotation.  So this is a totally different concept to the discussion of primary wave and secondary sub-waves of twice, 4 times, 8 times, 16 times, etc. frequencies.
2. I don't see why the statement "However, the piston pairs that move together tend to make secondary imbalance strong at high rpm, and the long length configuration can be a cause for crankshaft and camshaft torsional vibration, often requiring a torsional damper." is deemed inaccurate, or not necessary as you did not provide any reason.  If you believe in deleting this part, please provide reasons.
3. Two stroke V6 engines with un-split shared crank pin normally has equally spaced firing when the bank angle is 60 or 120 degrees.  I don't see any reason to support the deletion of "120 degrees" part in this.  Yiba (talk | contribs) 04:00, 8 July 2014 (UTC)
thread_title:  To 178.128.192.226 

message: "Steam locomotives commonly have balancing weights on the driving wheels to control wheel hammer caused by the up and down motion of the coupling rods and, to some degree, the connecting rods."
This sentence needs to be deleted as it contains 3 incorrect statements. The steam locomotive section would then be left with no content. It could be removed or I can add a short section
on the basics which is nearly finished in sandbox. Does anyone have a preference or recommendations for what goes in? It would need to be simple and would have cites.Pieter1963 (talk) 23:44, 26 August 2014 (UTC)
replies: text: Hi Pieter1963, thanks a lot for the comment.  It's a great help as I didn't like the part but have been unable to do anything about because I know so little, probably next to nothing, on steam locomotives.  Please replace the section as you see fit.  We can then talk about if the section deserves to be a separate article, etc. later.  Engine balance is such a complicated subject that it is extremely difficult for the article to be concise yet understandable for ordinary readers.  Please let me know if there are something I could help you on.  Yiba (talk | contribs) 01:15, 27 August 2014 (UTC)
replies: text: Hi Yiba, thank you for your encouragement and offer of help. I'm having to do a bit of reading whilst I try to confirm the content is sound.Pieter1963 (talk) 14:20, 1 September 2014 (UTC)
replies: text: Hi Yiba. I have added my contribution as a starting point for comment.Pieter1963 (talk) 21:16, 9 September 2014 (UTC)
replies: text: Looks very good.  A diagram depicting components to show what each description means would be nice.  "connected by driving wheels" may not be as accurate as "connected by driving wheel axle" or something similar.  Yiba (talk | contribs) 07:41, 10 September 2014 (UTC)
replies: text: I'll look for suitable diagrams. Wiki copyright rules look daunting. I have to correct contents numbering with last four appearing as steam locomotive. Added axles in definition as recommended.Pieter1963 (talk) 15:26, 13 September 2014 (UTC)

text: Pieter1963: Thanks for contributing to Wikipedia. I noticed that you added the whole section on steam engines but the references were terribly formatted. I just fixed most of them. It was a lot of work, which I was willing to do to make the world largest free (as in freedom) encyclopedia a bit better than it was, but we could have avoided that. Please in the future take a look at citing sources and follow the recommendations. Please check the citations that remain and fix them; I didn't fix some because I couldn't find information on year and author. Thanks. Mario Castelán Castro (talk) 00:12, 15 October 2014 (UTC)
replies: text: Mario, Wikipedia articles are a team effort because we all have different strengths/weaknesses and ambitions. It is good that you could use your strengths in this case. We all spend a lot of time trying to improve the quality.Pieter1963 (talk) 02:28, 12 January 2015 (UTC)
replies: text: Pieter1963: I agree that it's a collaborative effort (I wouldn't say a team work), my comments still apply. Collaborative efforts work better if work isn't duplicated. I suggested some points in which your editing of Wikipedia can or could (I don't know if you applied them) improve, so that no effort is duplicated with references: first when you add them, then again when another editor formats them properly. Of course, it's up to you whether to follow them, I will not insist. For reference, the references were  and I edited them to . Regards and thanks for contributing!. Mario Castelán Castro (talk) 03:08, 1 February 2015 (UTC)

text: Not what it says, although it  doesn't make much sense either. Greglocock (talk) 08:56, 4 December 2014 (UTC)
replies: text: Whether it's a typo in the book I can't say. However, "...trouble in the form of kinked rails, due to slipping at high speeds" says the wheel RPM gets up to something excessive beyond no-slip at high speed. CSR source also says 700 RPM.Pieter1963 (talk) 22:53, 11 January 2015 (UTC)
thread_title: Steam locomotives

message: I found better explanation on articles on the net written by other people. This content is almost zero. This article must be flagged as a stub.  — Preceding unsigned comment added by 86.120.17.142 (talk) 11:01, 4 June 2016 (UTC)
thread_title: Low quality content

message: Most uses of the term "inertia" in this article should be reworded to be more precise.  As the Wikipedia page on inertia describes, common use of the term "inertia" has given it a range of meanings (referring sometimes to mass, sometimes to momentum, and sometimes to a general principle), making it a poor choice in a technical discussion when a more precise term applies.  But I don't mean to suggest that it would suffice just to substitute "momentum" for "inertia" in phrases like "upward inertia"; these problems occur in sections that need thorough revision.  Tom239 (talk) 03:18, 16 January 2017 (UTC)
thread_title: Inertia

message: The mid-August edits by user:1292simon have left a considerable mess.  A major feature of the article was the referencing of the type of vibrational effect cause by different engine layouts and such.  The definitions of those reference numbers were removed from the "causes of imbalance" section by 1292simon's edits, and the references (see the bolded numbers throughout the remainder of the article) now are nonsensical.  
The references either need to be be removed, and the surrounding text updated, presumably with an expansion of the description of exactly what types of imbalances are being discussed, or we need to revert to something back around early August.  Rwessel (talk) 20:43, 22 October 2019 (UTC)
thread_title:  Edits by [[user:1292simon]] and vibrational effect reference numbers 

message: The amateurish section on torsional balance has been corrected by user:Bryllig, with the result that it no longer belongs on this page. TVs are excited by firing frequency and multiples thereof, not the fundamental balance state of the the engine. Greglocock (talk) 06:31, 30 November 2021 (UTC)
thread_title:  TVs