How Engine Balancing Works - Smooth Running Cars
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- Опубликовано: 25 авг 2024
- What is a balanced engine? Why do you want a balanced engine? An engine has uneven forces from rotational mass, reciprocating mass, and firing intervals. To balance the engine, we need to balance out these forces. Primary forces occur once per crank revolution, and are caused by reciprocating pistons. Secondary forces occur twice per crank revolution, and relate to the uneven speed of the piston as it moves throughout the cylinder.
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Another great video, man. I appreciate you going through so many of the performance modifications, as well as OEM features, and really spelling out what it is and the principles behind it. When I first became interested in working on cars and modifying OEM systems, I ran into a lot of elitist attitudes. Guys who had the knowledge, had little interest in teaching it to new comers. Most enthusiasts wanted to talk to others at or above their level of knowledge and understanding. Few people in the car scene have an accurate idea of how these systems work and fewer have the time to educate the less informed. On most make/model specific forums, the new guys are encourage to sift through years and years, of threads and posts, in order to glean a few needed nuggets of useful information that explain a particular subject. Thanks for taking the time to provide the base of understanding for aspiring gearheads.
Your very welcome! I, like you, was a bit frustrated when trying to learn about all these different systems, as you are correct in that it takes far too long to find the bits of important, useful information. So I think, why not save everyone else the time, and make a recap of what I've learned. Also, I have a poor memory, so I use my videos for reference. Glad you enjoy them, thanks for watching!
+Engineering Explained Hope good things have happened to you since putting up these breakdown vids. Good job dude.
+mg556linked I agree with you about everything you just said.
14 views, 21 likes, 0 dislikes. You are the man.
Breaking the laws of the internet!
Not anymore
Not anymore
10 years, 1 month, 22 days since posting/publishing and we're up to 431,000 views and 5,200 Likes! (I'm not sure that the bots/algorithm show Dislikes)
Please keep posting these videos! Your series on explaining how cars work has been amazing. I've spent the better part of the last few years reading random bits of information on the internet, but have always wished there was a source that explained how all these systems ultimately interact with each other. What also helps is how well spoken and easy to understand you are. Awesome work man, really appreciate it you have no idea.
Glad to hear it, thanks for watching!
This is extremely helpful. I've a loose framework for a homebuilt engine that I want to put into a homebuilt vehicle. A lot of your videos are helping me to understand things a bit easier before I start getting really technical.
Explain harmonic balancers and why they're necessary
It provides a resistance to the torsional vibrations (eleastic loading and unloading) of the crankshaft. The crank elastically deforms " twists" as the piston loads it...then it twists back when it unloads...oscillatory action. This action is resisted/dampened by the rubber between crank hub and the inertial ring on the harmonic balancer. The inertial ring will lead or lag the crank hub because of the rubber between them...the ring just cant catch up with the crank oscillations. The vibration energy leaves the rubber in the form of heat. Viscous fluid dampers have the same affect. These harmonic balancers are important to reducing fatigue on the crankshaft.
This came 9 years ago😢. Man you are a legend. I was searching for such a tutor like you for a decade. Love from India❤
I am very impressed. Keep up the good work. These videos really helped me and alot of others out too. Thank you.
You can enlighten a broad audience of varying levels of understanding on these very complicated mechanical operations with a very simple and common sense approach that can reach almost anyone paying attention during your videos. I personally have learned more just from your channel alone then when i attended different educational institutions throughout my twenties. Thank you and keep it up there is so much to know and so few who can help us in the knowing of it.
Good basic video explaining to anyone who just may be thinking about getting into engineering/motorsports design.
i don't know how many people still watching this but i started to watch logically ordered playlist. I'm interested in automobile studies just like you did (I hope). My ambition is to enter Engineering department in racing. but i don't know what to do & where to begin. if you have any tips for me please let me know.
At 6:43 "feel free to ass then blow"? You dirty dog you! :D
you are my favorite channel. point blank period. thank you for your knowledge expalining the math and physics behind why motors run how they do. @engineeringexplained
I want you to know i enjoy this channel. Im not sure why you started it. Perhaps as a passion project or as a scholastic project. Whatever the reason, I thank and congratulate you.
Great Video Sir ! I've studied engine balance before but I couldn't remember a single word of it so I was glad to see this really. I'm guessing this could last a few videos If you're going to go in depth for different engine configurations.
I will go into a few configurations, yes.
Good video. Need to watch it again.
I love this Channel!!!
Thank you very much sir, this is my 1st time dealing with engines and I am understanding perfectly!
nice video. i think it's way over-simplified but that's the point. nobody wants to go to school to learn this stuff. like the first , second and third derivatives (velocity , acceleration & jerk force) so you dummy it down for them. when people ask me about balancing an engine, i always tell them about the rule of 3. the easiest engines to balance have a multiple of 3 cylinders like 3cyl, inline 6, 60^degV6 , (NOT a 90^degV6), 120^degV6 eagle premier/dodge monaco, flat6(the choice of champions; porsche & subaru), v12.
that's because a piston spends 1/3 of its time at the top and 2/3rd's of its time down low (as we can see in your video as the red graph you have labeled "total". very nice). so 3 cylinders fill those 1/3rd's more naturally and secondary vibrations are minuscule, almost non-existent. more accurately, pistons spend from 1/3rd to 2/5th's of their time at the top (depending on rod length and stroke ratio) so 5cyl & 10cyl engines also balance well as long as they don't have relatively short rods.
so, all other engine have problems getting rid of secondary vibrations. balance shafts are for countering secondary vibrations and require significant horsepower to spin like 10-15% of total output.
another reason the rule of 3 isn't widely known is because 4-bangers & V-8's are simply too popular. nobody wants to hear about why v6's are better while FARM TRUCK is out doing wheelies on the 1/4 mile track. they choose to build a V-8 after seeing that.
seen quite a few of your videos now, trying to watch every one. Excellent teacher, some stuff I already knew but other a lot of it is really enlightening.
Hi, great video. Really explains the cause and effect of engine balancing. I was wondering if you could discuss the all of the forces that occur in an ICE in a single video. I think it would really help understand that there is more than just mass and friction at play....or maybe you already have a video and i haven't found it yet....again great channel
Great video as always. I would think that the secondary force associated with piston acceleration would be zero at the top and bottom of the piston stoke. However, your diagram shows a non-zero secondary force half way through the revolution.
Yes indeed, I'll have a video explaining further soon.
Harmonic balancers/dampers and flywheels also play a role in balancing. :)
That was an extremely good introduction to a very complex subject. I look forward to the next video, but not the mathematics that comes with it!
very clear and smart demonstration
This is really well explained .you know what you talking about. Thanks
How is balancing done on a VCR engine (like the VCR MCE-5)? Because the variable compression ratio is achieved by variable piston heights through a sort of geared coupling with the crankshaft. Therefor the balancing shafts will not function optimal since their postions are fixed to the crank. Is this assumption correct? Very interesting videos btw! keep up the good work! regards, a fan
Can you explain in a future video why and how different engine layouts sound differently, eg a v6 vs a v8 or a crossplane vs a flatplane? I guess it depends on the number of cylinders, firing order and exhaust layout but I can't exactly work it out.
Maybe exhaust pulses?
1:04 where do those moments in opposite directions on the pistons come from?
Would a boxer 8 have rocking couple?
Engineering Explained looking forward to it!
Great video, must be because it was published on my birthday!
u explain so easily. keep it up man!
Great video! Can you do one one how leaf spring suspension works?
Very nice, eagerly awaiting your video on the engine balancing for an inline 6 ;)
(hint: rb25de)
Another great video! I think you said you were going to, but I was hoping you would do a video comparison of engine layouts; boxer, inline, v... Keep up the good work!
Coming soon!
Actually this popped up when I was looking for airplane engines- excellent explanation!
Perhaps an expansion, such as why an I6 is naturally balanced while a V-6 isn't, and how the amount of V degree is established for the different cylinder arrangements. Perhaps some insight to the balancing problems of variable displacement engines such as the Cadillac V-8-6-4.
All in time!
Hey, I'd like to request a video about "performance" lightweight crankshaft pulleys vs. factory pulleys that are typically much heavier and what benefits/drawbacks they may have on your engine.
Arg! Started with your V8 video and viewed them in reverse! I'm gonna have nightmares about 3 and 5 cylinder engines! Wimper! 😥🤣😂
I love these engine physics vids
very well-explained! thanks a lot
The force on one side times the perpendicular distance from the axis of rotation must be equal on both sides, and the sum of those forces must add up to zero.
In other words, the sum of the moments of all forces must equal zero to produce a balanced system!
QUESTION:
considering the fact any Engine with just 3 Pistons are primarily unbalanced, and require a lot of counter balancing shafts and dual mass flywheel to keep em from shaking themself apart...
Does all this additional rotational Mass affect efficiency?
If we take a 1.2liter 3 Cylinder
and a 1.2 in line 4... wouldn't the 3 cylinder use more fuel than the 4 because of all that added balancing masses?
I am searching exactly this kind of vedio.Thanks
In the first column...rotational mass..why would the masses tend to rotate in left or right diresction..as shown..like which force is responsible for this?
Inline-6, v12, and crossplane v8 FTW!
Well explained! Was very helpful!
i can't believe i missed this video 7 years ago
in primary force of 1 per revolution .how come piston goes up, down and up again . does not it then rotate 1 and half revolution . could you pls clarify this
can you do a video showing why someone would double clutch and hell toe.shift and what are the advantages?
what are secondary forces in the engine , so that balance shaft is used
Difference between firing and primary forces please? They seem to be similar or at least inter-related.
Hey, sry regarding the rotational mass first example, I don't see where the moment of those masses comes from. I'm assuming the force pointing outwards is a centrifugal force, but what produces a moment pointing inwards?
how it feel of primary imbalance and/or secondary imbalance as persepctive of people/passenger, like vibrating, noise, etc?
Great channel man I dig it learn a lot can we see a video on balanceING a wankel rotary I'm a fanatic and one of the last things I don't have much grasp of mainly because of the tq of the rotor gears. Please I would love to hear your thoughts on this.
Thank you for another great video. I’m interested about the difference between a cross plane parallel twin and an 90 degree V twin. What are its pros and cons?
Can you explain the formula again? Doesn't a piston fire every 720 degrees? And what are you trying to calculate anyway?
Great explanation as always!
Thanks!
You forgot to mention that firing interval doesnt have to be even, since sometimes you even have to make it odd to balance it better like in a straight-twin for example. (Yes there are even firing ones but most inline-2 engines fire odd for engine balance (There even are inline 2 crossplanes). This just makes power delivery less smooth as a trade off. But unless its a 2 stroke engine 2 cylinder engines dont have power strokes even touching each other.)
I have one question, why not to fire more than one cylinder at the same time? wouldnt it give you more power?
how the math of counter weights is being calculated according to pistons and counter weights math ?
if we are dealing with one cylinder engine
Balancing is so important to the Rev
You really are doing gods work, but if you would sometimes add actual parts I think it would help :) like piece of crankshaft and stuff :)
GOOD job buddy!!!! loved your vid.
please explain how harmonic balancer work compare balancing engine ? thanks
Hi A good video. Do you understand why a 180 v8 crankshaft is prone to vibration? AND why the engines that do use them DONT vibrate and what are the limits of a 180 crank- is it stroke? or an recip weight? or? thanks-
love all your vids. thanks
I'm still confused about balance shafts. I know they fit in a compartment near the engine block and spin the opposite direction of the crankshaft/pistons in order to counteract the momentum of them to reduce vibrations and wear on the crank, but are they still used? And if so, what engines are they used in? I know they were patented by Mitsubishi. Thanks! Love your vids btw
I will have a few videos on the subject, soon!
Did that video happen?
If not, a balance shaft is generally applied to an inline 4 to counter the secondary forces.The secondary forces come from the conrod sweep as the big end rotates around the crank axis - think of how the big end moves from one side to the other while the top end stays in line with the bore.
The effect of this is to accelerate (neg and pos) the reciprocating masses twice during each crank spin. Accelerations -> Forces -> Vibrations if not countered.
The balance shaft is unevenly weighted just enough to cancel out the secondaries.
In saying all this, most competition Mitsi engines have their balance shafts removed for rotating mass reduction and less components to fail. I've built a comp 4G63 before and had this done.
Just means the driver has a little extra NVH to put up with, which no one cares about in racing ;)
Balance shafts were/ are (?) also used in some V6 engines, for example the Mercedes Benz M272. I guess because this was derived from the V8 (M273) and the cylinder banks were positioned in the "wrong" angle - 90 instead of 60 degrees - towards each other...
Thanks for your enlightenment,But I have a question please.
My single piston generator engine has a harmonic balancer,but I have to remove it because I couldn't get a new replacement and the engine is working smooth and noiseless.what impact will it have on the engine when on full load?
This is why the boxer engines are good, balance, and also straight six engines are known for good balance, and my 4b11t engine has good balance.
hey i would like you to explain about internal engine friction.thanks for sharing your knowledge :D
why some 4 cylinders have balance shafts and some dont like the 420a motor dont have any balance shaft.i heard that the manufacture wanted to save alot of time and money and skipped the balancing of the engine.and substituted the quick installation of balance shafts to eliminate vibration.
engine balancing tuning is for increase performance of course but for engine life or durability will be cost?
let's say for stock v6 engine
Good work but. Explain practically some things didn't understand on chart. About increase counter wait and balancing epically single and double slender motorcycle engines.
I know this is an old video but I was just thinking, if someone puts lightweight rods and pistons in with a stock crank, isn't the motor way out of balance then?
love this, if you get a chance can you explain carburetors?
Carburetors - Explained
Hi,I don't know if this would be a good topic or not but I'm curious to know more about engine mapping.
I think 180 Deg. in your formula is a constant number not because of it fires in every 180 Deg. as you said.or else i need explanation.
Why do the rotating rods want to rotate inwards?
Would you give us your thoughts on the new Triumph 900 with 90° crankpins? And....sound...
Thank you for the effort that you put into these videos. It is much appreciated!!
Just a question... what is meant by having a crankshaft balanced at (for example) "60%" or "65%".... Is that related to this???
Great video
What is the best engine configuration in your opinion?
At 3: 16 "probably one that goes up and then down and then up and then down, and that shakes a lot". But now seriously... he rocks, that's one of the reasons I am studying it. He does exactly what an excellent professor should do, make it simple, easy and interesting.
Hi, Could you advise what you mean by moments .. I could not follow it
hey jason , I would like to thank you for posting such wonderful videos , keep up the good work
I do have a question though ,, i watched all the videos you posted about inline 6 V8 and V12 engines and my question is the following ,
In descending order , can you please list which one is smoothest ?
inline 4 ?
inline 6 ?
V8 ?
V12 ?
Thanks
Silver17dragon V12 (smoothest), I6, V8, I4. This can of course change based on the design and use of counterweights, but as a general assumption could be considered true.
Engineering Explained Rotary/Wankel engines are smoother than V12s though right?
Engineering Explained What about VR12? I don't mean W12, VR12 has 2 banks of I6 like V12 does, but are they naturally balanced? What about W18? W16?
@@deldelz465 Any Wankel rotary engine is perfectly balanced. Even single-rotors.
You have something about diesel fuel supply system?
Hi, I have a doubt regarding the counterweights.
Does the counterweight added to balance the rotary mass need to have the same weight? If different there will be inertia difference right?
but does it make it less efficient - should 6 cly boxers be more efficient in some way because it does not need balancing - what about 3,5, 6, V8 and V10s ??
can you do a episode on harmonics? Sorry dunno if you have but in theory, will increasing flywheel mass bring the critical harmonics point lower in the revolutions?
Is it normal that I don't really understand at the forces explanation part?
im not sure why the piston moves faster at TDC than BDC. I can imagine this for a single cylinder engine but how can that be true for a multiple cylinder engine. ?
Love this video !
Hi, thanks for the complicated video, I'd like to request a video over car engine liters e.g 1.2, 1.6, 1,8 etc and what do they contribute?
+Simphiwe Mphiwe Basically, a bigger engine means you can make more power out of it. The displacement refers to how much water the engine would displace total if all the cylinders were full. The more space you have, the more fuel you can get into the cylinder, and the more fuel you can get in there, the more power you can get out.
Now, making an engine bigger also means that the rotating and reciprocating components are heavier, which also means the imbalances of the engine will be more pronounced.
That's why extremely small engines like motorcycle engines can rev up to 20,000 RPM, because the crankshaft and pistons are smaller and don't create as much movement on the engine.
So the reciprocating mass acts much like a 3 phase AC sine wave, pretty cool
hey there! can you do a video describing how a twin intake turbo works?? idk if you already have done a video on it. but please do one on twin intake turbos!
The layout on the left is a twin-intake twin turbo set-up. I believe this is what you're referring to? Twin Turbo - Explained
Could you explain to me how you get the direction of the "moments"?
+Vibhor Malik yes i also think he should have explained that. but i explained it this way to me: look at his 2nd example, where the pistons are not at the same position but 180° twisted. now imagine u hold only one in your hand (one arm). and then u rotate that thing between your thumb and second finger, you roll it. this is the way you get the moment ...
in other words: connect the pistons with a STRAIGHT line. the force along the line will be irrelevant, the forces 90° to the line will be the moment
A counter-rrotating crankshaft would be the smoothest, and perhaps negate the need for a harmonic balancer.
How can we balance the reciprocating mass of a single cylinder ?
more on secondary forces! haha, good vid
You got it! I will have more videos on secondary, they aren't explained too clearly on many locations of the internet.
Here's a question: If a V8 (with a 90 degree engine block) crankshaft plane is most balanced with 90 degree intervals, why do some V8s (also a 90 degree engine block) use a flat plane crankshaft, which has 180 intervals?
That's a great question, to which I can proudly claim I will post a video on. :)
Thanks!
because by using a flat plane, you can organize the firing order to make an engine much more responsive. A flat plane V8 is basically 2 inline 4 mated at the crankshaft. It is also lighter because it needs less counterweights for balance purpose. Thats why it's only used on high performance sports cars like Ferraris and on race cars.
Extreme2TheBravest Flat plane v8's have 90 degree intervals mate. When one plane is at TDC and BDC, the other plane MUST be at the midpoints. No exceptions.
Good to know.
1. Are Boxer engines easier or more difficult to balance?
2. Are Rotary engines easier or more difficult to balance?
3. Apart from vibration, what other effects does a badly unbalanced engine cause to a car's performance?
1. Easier, regarding primary and secondary forces.
2. Great question.. I believe easier, since it's all rotational and nothing reciprocates.
3. Well.. vibration causes problems, and is the direct result of not balancing. You can still create something powerful with large vibration, but you wouldn't want to unless the application didn't matter (short lifetime, heavy vibration anyways, etc.).