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)
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!
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.
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.
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.
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 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.
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.
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.
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.
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.
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.
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.
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.)
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!
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.
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.).
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
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?
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.
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?
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?
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-
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
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
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...
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.
Does the pairing of sister cylinders assist with balancing and power production as well? With 4 cylinders, 2 are firing at the same time at TDC(or right around tdc) a certain number of degrees apart from the other 2 cylinders causing more explosions per minute correct? Great videos by the way, thank you!
4-cylinder engines only have a single cylinder firing at a time. When one is firing, it's sister has just completed the exhaust stroke and is about to begin intake. Power is correlated with the amount of fuel burned - which means it goes up with more displacement, better scavenging efficiency, and more boost pressure. More cylinders generally means more displacement, but not always. The real advantage of more cylinders is that there is less of a gap between power strokes meaning a smoother delivery of power.
what are your thoughts on a lightweight cnc crank pulley. i have a 2000 s40 turbo and many people have used these from ARD tuning. i heard mixed thoughts on why people think they are great or bad for a fun daily driver. what is your opinion? thanks! i really enjoy all your videos
what if you have a 90 degree v twin and the two rods share a common journal, do you make one bob weight, or do you have to make two , one for each assembly then aim them a certain way in relation to that pistons stroke ?
+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.
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!
I take it that the firing forces equation won't work for a rotary engine. Do rotaries have a specific firing equation or is the ignition phase once every 350 degrees of the eccentric shaft since the shaft rotates 3 times for every full rotation of the rotor, which would coincide with one e-shaft rotation per rotor face and firing cycle?
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.
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?
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.
I drive a citroen SM with a Maserati V6 engine. This engine is a 90 degrees V6 odd fire engine. In fact it are two 3 cylinders in one cast.. The crancshaft is as a 3 cilinder engine but has two pistons conected. Because of the 90 degrees angle there are never two pistons at tdc at the same time!! The firing forces are very different from normal engines. I think there is a Buick engine with the same configuration. I want to use lighter pistons. How do I get this balanced.
+renardautomobiles My experiences with the Australian version of the Buick 3.8Ltr V6 (which has a balance shaft counter rotating at 2X crank speed running in the valley under the intake manifold to cancel the rotating couple) is you take your crankshaft, rods, pistons, front balancer/pulley and the flywheel/ flex plate to the balance shop give them lots of money and hope they know what they are doing. Changing the mass of anything in an odd fire engine is tricky. Later 3.8 Buicks had offset crank pins, at first glance the big end journal looks normal then you notice each half of the same journal is 30 Degrees offset making them even firing engines.
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?
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. I'm a little rusty myself. So would you call an engine balanced if the sum of your mass times acceleration vectors cancel each other out along the time domain (or crank angle depending on how you look at it)? Hopefully someone can give a quick response. Or is it possible to use impulse using crank angle instead of the time domain? Again, very rusty and just curious!
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!
More on secondary forces, I still don't understand it. Is it because one down stroke is in combustion and another might be in compression? Is my assumption that a V8 fires 2 cylinders every 90 degrees. And do you use imperial or metric units at your job.
It's really quite confusing, so you're not alone. Took me ages to get my head around, ended up writing a 30 odd page summary. Soooo... The simplest piston layout is called the scotch yoke or scotch crank. It moves in pure sinusoidal motion. The acceleration of this piston is purely sinusoidal as well, and since force is only mass * acceleration, the force is sinusoidal in step with the piston acceleration. This sinusoidal force experienced by the piston is the primary force. Now, in cars, a scotch crank is not very workable and so pistons have connecting rods that connect to the crankpin and pivot around it. Without going into detail, this change creates a second acceleration of the piston, in conjunction with the first. This is the secondary force. The two forces interact with each other, sometimes adding sometimes subtracting. The end result is what looks like a slightly wonky sinusoidal wave. The magnitude of the secondary force is approximately a quarter of the primary force, so not a lot. Not enough for manufacturers to bother balancing I4 engines, which last pretty much forever anyway.
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.
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.
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?
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?
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?
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
The pistons moving up and down do NOT counteract each other. There are weights on the opposite end of the rods that counteract this. Have you ever opened an engine?
With a can opener, yes. It depends on the layout. In an inline six the pistons perfectly balance out eachothers forces, so the use of counterweight is minimal (there are other things creating imbalances besides the pistons). Engines such as V8's and V6's use counterweights because they are not inherently balanced. But I'm sure you already knew..
Engineering Explained This is correct. CW are rarely used to balance the reciprocating masses - usually in out of balance arrangements like 3-cyl. The CW you see on the crankshaft are there to balance the rotating mass of the crank pin and lower portion of the con-rod - mainly to reduce bearing loads on the main bearings. Pistons do counteract each other.
+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
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.
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???
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)
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.
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.
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.
I am very impressed. Keep up the good work. These videos really helped me and alot of others out too. Thank you.
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❤
Good basic video explaining to anyone who just may be thinking about getting into engineering/motorsports design.
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 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.
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.
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.
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.
I love this Channel!!!
Thank you very much sir, this is my 1st time dealing with engines and I am understanding perfectly!
Good video. Need to watch it again.
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!
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.
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.
At 6:43 "feel free to ass then blow"? You dirty dog you! :D
Harmonic balancers/dampers and flywheels also play a role in balancing. :)
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!
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.)
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!
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.
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.).
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
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?
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?
This is really well explained .you know what you talking about. Thanks
Engineering Explained looking forward to it!
Great video, must be because it was published on my birthday!
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?
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?
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-
Very nice, eagerly awaiting your video on the engine balancing for an inline 6 ;)
(hint: rb25de)
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
Actually this popped up when I was looking for airplane engines- excellent explanation!
u explain so easily. keep it up man!
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...
Would a boxer 8 have rocking couple?
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.
Does the pairing of sister cylinders assist with balancing and power production as well? With 4 cylinders, 2 are firing at the same time at TDC(or right around tdc) a certain number of degrees apart from the other 2 cylinders causing more explosions per minute correct? Great videos by the way, thank you!
4-cylinder engines only have a single cylinder firing at a time. When one is firing, it's sister has just completed the exhaust stroke and is about to begin intake. Power is correlated with the amount of fuel burned - which means it goes up with more displacement, better scavenging efficiency, and more boost pressure. More cylinders generally means more displacement, but not always. The real advantage of more cylinders is that there is less of a gap between power strokes meaning a smoother delivery of power.
love this, if you get a chance can you explain carburetors?
Carburetors - Explained
1:04 where do those moments in opposite directions on the pistons come from?
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 :)
what are your thoughts on a lightweight cnc crank pulley. i have a 2000 s40 turbo and many people have used these from ARD tuning. i heard mixed thoughts on why people think they are great or bad for a fun daily driver. what is your opinion? thanks! i really enjoy all your videos
I love these engine physics vids
what if you have a 90 degree v twin and the two rods share a common journal, do you make one bob weight, or do you have to make two , one for each assembly then aim them a certain way in relation to that pistons stroke ?
Great video! Can you do one one how leaf spring suspension works?
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.
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
Would you give us your thoughts on the new Triumph 900 with 90° crankpins? And....sound...
I take it that the firing forces equation won't work for a rotary engine. Do rotaries have a specific firing equation or is the ignition phase once every 350 degrees of the eccentric shaft since the shaft rotates 3 times for every full rotation of the rotor, which would coincide with one e-shaft rotation per rotor face and firing cycle?
Good question Nate
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.
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.
I drive a citroen SM with a Maserati V6 engine.
This engine is a 90 degrees V6 odd fire engine. In fact it are two 3 cylinders in one cast..
The crancshaft is as a 3 cilinder engine but has two pistons conected.
Because of the 90 degrees angle there are never two pistons at tdc at the same time!!
The firing forces are very different from normal engines. I think there is a Buick engine with the same configuration.
I want to use lighter pistons. How do I get this balanced.
+renardautomobiles My experiences with the Australian version of the Buick 3.8Ltr V6 (which has a balance shaft counter rotating at 2X crank speed running in the valley under the intake manifold to cancel the rotating couple) is you take your crankshaft, rods, pistons, front balancer/pulley and the flywheel/ flex plate to the balance shop give them lots of money and hope they know what they are doing. Changing the mass of anything in an odd fire engine is tricky. Later 3.8 Buicks had offset crank pins, at first glance the big end journal looks normal then you notice each half of the same journal is 30 Degrees offset making them even firing engines.
renardautomobiles
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?
Balancing is so important to the Rev
Arg! Started with your V8 video and viewed them in reverse! I'm gonna have nightmares about 3 and 5 cylinder engines! Wimper! 😥🤣😂
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. I'm a little rusty myself. So would you call an engine balanced if the sum of your mass times acceleration vectors cancel each other out along the time domain (or crank angle depending on how you look at it)? Hopefully someone can give a quick response.
Or is it possible to use impulse using crank angle instead of the time domain? Again, very rusty and just curious!
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!
More on secondary forces, I still don't understand it. Is it because one down stroke is in combustion and another might be in compression? Is my assumption that a V8 fires 2 cylinders every 90 degrees. And do you use imperial or metric units at your job.
It's really quite confusing, so you're not alone. Took me ages to get my head around, ended up writing a 30 odd page summary.
Soooo... The simplest piston layout is called the scotch yoke or scotch crank. It moves in pure sinusoidal motion. The acceleration of this piston is purely sinusoidal as well, and since force is only mass * acceleration, the force is sinusoidal in step with the piston acceleration. This sinusoidal force experienced by the piston is the primary force. Now, in cars, a scotch crank is not very workable and so pistons have connecting rods that connect to the crankpin and pivot around it. Without going into detail, this change creates a second acceleration of the piston, in conjunction with the first. This is the secondary force. The two forces interact with each other, sometimes adding sometimes subtracting. The end result is what looks like a slightly wonky sinusoidal wave. The magnitude of the secondary force is approximately a quarter of the primary force, so not a lot. Not enough for manufacturers to bother balancing I4 engines, which last pretty much forever anyway.
I will have an additional video on it. Cheers
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.
i can't believe i missed this video 7 years ago
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.
Did you use any textbook/web resources in order to produce this video? If so could you provide a struggling student with a link or 2
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?
great video but I don't really get it. In terms of the engine what is the rotational mass is it he pistons?
SupremeGamingDude The pistons are reciprocating. The camshafts, crank, pulleys, etc rotate.
Engineering Explained ok thanks alot now I understand
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.
Great explanation as always!
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?
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?
can you do a video showing why someone would double clutch and hell toe.shift and what are the advantages?
very clear and smart demonstration
hey i would like you to explain about internal engine friction.thanks for sharing your knowledge :D
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 job buddy!!!! loved your vid.
Can you explain the formula again? Doesn't a piston fire every 720 degrees? And what are you trying to calculate anyway?
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
Difference between firing and primary forces please? They seem to be similar or at least inter-related.
very well-explained! thanks a lot
I am searching exactly this kind of vedio.Thanks
Hi,I don't know if this would be a good topic or not but I'm curious to know more about engine mapping.
The pistons moving up and down do NOT counteract each other. There are weights on the opposite end of the rods that counteract this. Have you ever opened an engine?
With a can opener, yes. It depends on the layout. In an inline six the pistons perfectly balance out eachothers forces, so the use of counterweight is minimal (there are other things creating imbalances besides the pistons). Engines such as V8's and V6's use counterweights because they are not inherently balanced. But I'm sure you already knew..
Engineering Explained This is correct. CW are rarely used to balance the reciprocating masses - usually in out of balance arrangements like 3-cyl. The CW you see on the crankshaft are there to balance the rotating mass of the crank pin and lower portion of the con-rod - mainly to reduce bearing loads on the main bearings. Pistons do counteract each other.
how it feel of primary imbalance and/or secondary imbalance as persepctive of people/passenger, like vibrating, noise, etc?
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.
love all your vids. thanks
Well explained! Was very helpful!
Hi i have been told that they use bob weight to balance v block but not for in line engine, do you know why?
Yes, I should have some videos on it soon. :)
I have one question, why not to fire more than one cylinder at the same time? wouldnt it give you more power?
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.
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???
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.
please explain how harmonic balancer work compare balancing engine ? thanks
Love this video !
how the math of counter weights is being calculated according to pistons and counter weights math ?
if we are dealing with one cylinder engine
Hi, Could you advise what you mean by moments .. I could not follow it
what are secondary forces in the engine , so that balance shaft is used