Dual Mass Flywheel - Explained
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- เผยแพร่เมื่อ 30 มิ.ย. 2024
- How do dual mass flywheels work? What is a dual mass flywheel? DMFs have two masses (really!). The first mass is matched with the engine crank, and it transfers engine torque through springs to another mass, which is connected with the transmission (and clutch housing). The goal is to reduce torsional vibration through the drivetrain, which is particularly useful for diesel engines, low idle speeds, and low cylinder counts.
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In my own experience, the dual mass flywheel is designed to fail prematurely and then suck all your money out of the bank.
+davidrobert2007 Planned Obsolescence. Although some cars have after-market SMF options to replace the DMF.
If the crankshaft and all the components are designed to use a DMF that absorbs peak, i would say that a SMF would be cheaper and give a better response but it will also wear out faster the other components because its not damping the impact of strokes...
A single mass flywheel does not wear out. It's a solid piece of metal.
"i would say that a smf would be cheaper and give a better response but it will also wear out faster "THE OTHER COMPONENTS" because its not damping the impact of strokes..."
azagedon your transmission will wear out prematurely, something has to give. I have heard from Luk that doing “modifications” like these will cause other damages to other components as DMF was designed to cause less stress to the drive train. And obviously if it is a solid flywheel then you have to use a traditional clutch disc with torsional springs and that will increase rotating mass of the transmission input shaft and cause harsher shifting and more wear on the synchro than before.
Great video, as expected. I looked for explanation and you had a clear and concise one, thank you!.
Dear Inventor of the Dual Mass Flywheel
Having now had to replace the DMF on my UK Ford Focus 1.8 tdci THREE TIMES, I would like to make a suggestion:
If this wonderful creation of yours is also used on large diesel trucks and the like, why not find the largest one on the market and then push it sideways up your bottom. It would make me feel better knowing that you feel equally as shafted as I do each time I'm forced to pay the garage for replacing your piece of junk invention.
Thank you very much and goodnight.
happydavid13 replace it with a lightweight single mass duh
If you had to replace it that much the issue is obviously not flywheel but the driver. I have a car with dmf and no issues what so ever. Almost 100k miles on it.
Alex2900 you are making an erroneous assumption as I am in fact a very gentle driver. I’m still driving the same car and it has now covered 290,000. I fitted the last dmf myself 3 years ago and it is still working well. The previous one lasted a matter of weeks before developing a fault as I was reversing into my drive. There was a clunk and from that moment onwards it was out of balance and the car was almost shaking itself to bits. Since the flywheel I fitted myself has now lasted over 3 years, I must revise my opinion a bit and say that whilst ever they are working, they do work well and fulfill their role of reducing shocks to the drivetrain. But they can develop internal faults and lock themselves in an out of balance position even when used by the gentlest of drivers. I apologise that you were triggered by the harshness of my original comment.
@@happydavid13 maybe because it's a Ford Focus? Not known for their amazing engineering lol.
I've had an E39 525d with perhaps original clutch and dmf, drove that car for over 4 years before I sold and got a 530d. It ran without a problem tbh.
Maybe not the DMF is the fault here but Ford is? Everything can work good if it's engineered and designed well.
@@omfgwtfbbq90 you have a valid point! But I have come to the conclusion with the dual mass flywheel’s that it’s often the luck of the draw. Even if you drive them carefully they can still pack in relatively low mileage.
A very good informative video and no annoying repeat facts, well scripted & presented, thank you.
I though that the springs in the clutch are used for diminishing the impacts in transmission system when clutch release. For me the function that you mentioned (absorbing energy of the explosion and gradually restoring for the system) are done by the flywheel. Its a interesting approach!
I'll put my two cents about engine vibrations, if you wouldn't mind :-)
On the opposite side of a crankshaft there is a "torque vibration damper" (I dont't know how is that thing called exactly in english). Usually it looks like an elastomeric spacer between two parts of a band wheel. It's looks very small, so that most of people do not even know that it actually exists, but it works. Usually it's not a separate from the band wheel part, and can't be disassemblied. So the band wheel is also a sort of dual mass flywheel in modern engines. The vibration(oscillation) can break crankshaft at some definite (resonance) RPM range. The damper's purpose is to move that resonance range to higher RPM's, so high that normal engine can't reach it (maybe 10000-20000).
I love your channel I learn so much keep up the good work
Where is the squeak generator?
What I got from this video is that it's very difficult to shake your hands and different speeds.
Should do a video on how different types of oil affect the engine and why each engine has its own unique one.
Wouldn't there be a slight phase lag of the secondary mass torsional peaks with respect to the first mass peaks?
stoppsi Sure, drawn to understand the concept.
I love you man
How often do you predict you with be attending events and uploading videos or Press automotive car comparative vents? I found the short evaluations very interesting, also love all the engineering videos
Thanks! Glad you enjoy the videos. I wish it was something predictable, but most of the time it's not. I can see as far as about a month into my future. That said, I do have two events on the calendar, one for electrics and hybrids, and one for sports cars. Both of these are a good ways out, and I'll have to do some rethinking as far as how to release the videos. 27 in a week was too much for most people haha (understandably). Working on a few aero explanations for the time being.
You need to replace a Dual Mass Flywheel with the clutch because of the mechanical wear. Depending on the design you can either get play between the two parts that causes the clutch to drag or they can break apart entirely due to centrifugal force and smash up the bell housing etc.
I just bought an e46 with a dual mass flywheel and this makes so much more sense now.
Can u do a video on how to change your indicator fluid?
The 1993 Ford probe I had for my first car had a solid flywheel. I never noticed any vibration.
Hi great video as normal isit possible for the two parts too seperate?? as mine is noisy 😭 would it be worth a solid flywheel conversion??
Cheers for reading
Would the extra vibrations from a single mass fly wheel hurt anything or is it mainly for the people driving?
hey man, will you need to change the type/viscosity of gearbox oil if you go from a dual mass flywheel to a single mass flywheel?
good video
Can't wait to replace the dual mass flywheel in my Fiesta ST with a lightweight, single mass flywheel.
Make sure you get a sprung clutch disc. Or the rattling will drive you crazy
+krjcook TH-cam 370z flywheel rattle... Im looking to replace the clutch on my G37 (same as 370z) and im kinda bummed if i go to a lightweight flywheel its gonna sounds like a rock crusher...
+Ryan Fonseca just find a manufacturer who makes a sprung clutch.
@@ryanfonseca3270 how it all went?
Will you please explain why some people say a lightweight or single mass flywheel takes away torque? I don't understand that..
Nice video
Can I change from dual mass to a single mass flywheel on my car?
93' Acura Legend with a Type ll Motor meshed up with a 6 speed. They come stock with a DMF. Makes it buttery smooth especially for the year make. Too bad they're over 1k for a new flywheel if you can even find it. Plus DMF springs can get worn as well as the surface. (maintence)
I replaced my DMF for a SMF. Less rotational mass, also can be easily resurfaced for further use. Cheaper clutches to boot. Won't have as smooth and luxurious power delivery.
By using this dual mass flywheel ,the springs that is present in clutch is replaced ??? Or both must be present ??
Hi I know this may seem a little of tangent to the video, but I was wondering the real world effects of tire width (surface area) and friction. I ask this because in my physics class I learned that surface area does not effect friction (may or may not be accurate to certain points?). However from other sources (Lots of them) I have been told that wider tires increase "grip". The only rational point I can think of is that the bigger surface area and mass could absorb more thermal energy without temperature change, thus keeping the material characteristics the same. I am not sure I completely understand these concepts. Is it that the term "grip" has nothing to do with friction? I am not sure. I would be very grateful if you could provide any insight on my comment. Thanks!
one question, how to optimaly drive to prolong its life time?
Don't drive it.
That is one intelligent answer from one intelligent kid. Thank You for Your constructive and very useful comment.
happy to help!
For a diesel, drive it for long trips (don't drive it too much in town, traffic... Etc), keep the rpm above 2000rpm, don't let the engine heat by letting it idling for half an hour, 1min for oil to get to all the engine and start moving slowly without passing 2000rpm.
Hi I have a BMW 330d been increasing power now want to upgrade clutch to handle more it is a dual mass flywheel car would I need just clutch plate to take more or a upgraded dmf also don't won't to go smf they don't seem to do better dmf so would a new standard one be enough many thanks
I loved the video, Jason! I have a MK4 2004 VW Jetta GLI 2.8L 24v VR6 6 speed Manual 02M. Planning to buy a South Bend Daily Stage 3. Do I need to buy a new Dual Mass Flywheel, or should I keep the one that came with my car as OEM? I think mine is DMF LuK 240mm. Should I buy a brand new DMF from LuK that matches mine? Mine is almost 20 years old or should I switch to a Single Mass Flywheel? I hate to install a brand-new aftermarket Clutch of this caliber and keep the old DMF. If you recommend replacing the DUAL MASS FLYWHEEL, with a SMF brand model, will it go well on the MK4 platform for this car? Sorry for these type of rookie questions, I am pretty sure you get asked these all the time, my apologies.
Great video. Do flux capacitor next!
o3tomas
Is that the reason (or at least partially) why newer diesels are much quieter. If not so what are the reasons for the lack of "rattling"?
P.S: I don't believe latest common rails make all the difference cuz I've heard them being pointed as the factor.
Awesome video man! Is there much energy loss in the springs due to their resorting force not being the same as the amount needed for compression?
Ray O'Mahony I wouldn't say so, springs are more of energy storage devices rather than energy dissipation (through heat).
Cool, I know it would be a hard to measure but just was wondering your take on it!
Engineering Explained but surely during heavy acceleration the springs will always be under some tension while the clutch is engaged, and only expand back out when the pedal is depressed? So they ARE storing the energy, but they aren't releasing it into the transmission, so it's basically useless in that particular situation?
I realize it's more geared towards comfort than acceleration, but couldn't an up rated tv damper on the crank pulley do the same job?
+lolz larkin This is a good question I wish to have answered also. To my understanding, whilst driving with the clutch out (in gear) and under power, the springs would be always compressed, albeit to varying degrees depending on the power output. The springs will then expand again when your foot lifts off the accelerator. Does this place the springs under constant load and therefore reduce the spring's life?
It will depend on how stiff are the springs inside the DMF and i assumed they're tuned to the vehicle. Under acceleration the torque will decrease while the rpm is getting higher, so in fact you will have the stored energy coming back to the transmission due the engine natural loss of torque at higher rpms, of course this happens gradually. In a SMF there's no energy stored in that matter, so the power delivery its immediate, yet the energy will be induced to all the components before and after of the flywheel, which would wear them out faster.
That part about cost... YUUUP! Literally an order of magnitude more expensive to get a DMF clutch vs a non-DMF
Would they not be substantially heavier than a regular flywheel? I would think these would only be used in extreme cases of vibration like with diesel engines as the added rotational mass to the drivetrain would hurt fuel and power, no?
You can make the masses as heavy or light as you want. The whole assembly usually weighs the same as the single mass equivalent.
The explanation was great but it would get better if you have done it practically. I mean if you use a real dual mass flywheel to explain it would be much easier to understand than using a white board. So my request is to make another video on the this topic but practically.
All the best
Are dual mass flywheels used on generators aswell?
i could be wrong but the area under curve should be the same for both mass.
Wouldn't it be possible to integrate a similar system on the clutch pack itself for similar results? As you said, there are also springs, but it's a simpler design.
Also, this system has an effect on the clutch pack degradation? It seems that smoothing the torque delivery would make the clutch pack last more.
Thiago Silveira Yes, you can do it on the clutch itself (which is what single mass flywheels do), however this reduces the vibration before it reaches the transmission (which is connected with the clutch).
Is it bad to replace a dmf on my Lexus is250 that’s in there already to a single with a spring loaded clutch ?
Can someone explain how the springs dampen the vibration?
here most of us replacing it with a solid.flywheel kit as it gives too much trouble and too expensive to replace. By experience I can add that when a dual mass starts to wear out you can say goodby to the starter too, so you need to get a new starter as the one on your vehicle will be beyond repair, and I mean it. so the best solution is to get rid of it. price wise here in Malta I would have paid some 1,400 euros 4 years ago for a dual mass kit original for a ford transit minibus 2004 2.4ltr 125ps model excluding the starter. Its simply insane.
Doesn't a four stroke engine only have one power stroke per 720 degrees? or by power stroke do you mean returning to TDC, I'm a little confused @EngineeringExplained
so basically you get dampening by the FW and you have a solid clutch plate while with a SMFW the dampening is done by the clutch disc, basically both do the same thing except the clutch discs seem to have stronger and more reliable. The DMFW has the core that is heavier than the middle of a clutch disc but that only protects the spline of the shaft better otherwise the shaft mass has enough mass to act as the center of the DMFW.
No mention of all the down sides of a dual mass? More rotating mass on the motor = more time for the engine to change speed between shifts.
3e the opposite thing happens because with duel mass and trans input sprung hubs with marcel springs you have more slack / time and some slipping before you apply full power but at that point its mostly if not all the way engaged ready to go vs big shock loading = lots of clutch slip or something giving way = a bad day
Jason what do you think about an idea of eliminating the flywheel and replacing it with Flywheel KERS element to reduce weight and many other benefits it would bring, would it be a good idea?
Mikee CZ If your goal was to reduce weight, better to switch back to a SMF. Adding KERS will add weight and plenty of complexity.
ye but i mean for cats that already use flywheel kers
Mikee CZ A KERS unit has significant weight, I doubt there would be any weight savings over a conventional flywheel.
patw52pb1 as i said, i meant it for cars that already have kers...
Help please.when i let my clutch out in first gear at around 1200rpm my car starts to kangaroo i then dip the clutch and start of again smoothly could this be a dmf fault thanks
My BMW E39 525d has a Dual mass flywheel as well. But it has a smooth 6 cylinder. Does it even need a DMF?
What will be the main differences felt if I will swap to a single mass flywheel? It already has one of those rubber driveshaft dampers. Will it have rougher gear shifts or what?
4 years passed by. Have you learned the answer? I want to know for my 3.0 Z4 E85.
@@DaVinci-uh4tr a diesel 6 inline is always a little rougher running than petrol, so the DMF dampens the shocks towards the gearbox and makes a smoother ride.
@@omfgwtfbbq90 yet it's an I6. Have you stayed with DMF?
@@DaVinci-uh4tr I haven't changed anything, I sold the car last year. Now I have E39 530d M-Touring :)
It has had the clutch changed, and I think the DMF too.
Slightly off topic, but you mentioned the lower cylinder counts in an effort to save fuel and it got me thinking. Why do automakers revert to trading in their 6.0L V12 for 4.5L V8? Would it not save the same amount of fuel, yet keep the silky smoothness of a V12 to just create a 4.5L V12? Or does cylinder count matter more than displacement for fuel consumption?
Trey Perry More cylinders = more moving parts, and typically more frictional losses as you have more contact points. More moving parts also means more energy lost.
@@EngineeringExplained Why don't they make single cylinder cars then?
so, the reason my transmission sounds like a blender with marbles in it is the fact that the stock clutch was replaced with an aftermarket one and most probably the stock dual mass flywheel also was replaced with a straightforward single mass flywheel... right?
it's a single turbo supra with aftermarket clutch and the V160in it makes all the noises when in neutral, or when cruising/decelerating. it's quiet when the clutch is depressed (although the clutch also makes noises, albeit different ones :D ) or a continuous power is fed to it.
nihontoman kinda sounds like you've got an aftermarket twin plate dude. Get under there and check it out
Yeah, I'm gonna do just that, but still gathering up some info before I do that... the car is still very new and all the noises it makes made me nervous but turns out everything should be noisy, except for the worn out rear hatch rubber stops :D
It sounds like you have a single mass flywheel.
I just changed the clutch in my 2012 Ford focus with 70,000 miles. The reason for changing the clutch was the throw out bearing was sticking. I had never heard of a dual mass flywheel before. Looking up the price it is only $65. I did not change because there was nothing wrong with it.
IGo ProEVERYTHING
Had any problem since then?
You might have missed a zero in $650
@@JeanV1986 nope
A lot of people in the first gen CTS V community will tell you that the dual mass flywheel is less than desirable. It's common for them to swap with a lightweight single. I'm pretty sure mine is crapping out on me. I like that they allow you to creep at low speed without stalling but they seem like a burden to this car. Maybe it's not so much the technology as it is the implementation though.
It's almost like a fast Fourier transform for your engine.
But why do we care? Does it matter if these vibrations reach the transmission? Is it just for noise reduction, or does the vibration have an impact on wear in the transmission and components further downstream?
Most people ride the clutch at lights/junctions etc rather than putting the gearbox in neutral. This imposes greater wear on the clutch mechanism. The consequent and inevitable (and arguably needless) replacement of the worn clutch becomes a whole financial dimension above the cost of a standard clutch if the car's fitted with one of these DMFs. So be aware of that very likely cost if you're buying a secondhand vehicle above say 70k miles.
Keyboard Dancers unless you do it on purpose to tell your wife its broken, then you can upgrade to performance shit and she wont know the difference. I got it all worked out.
+Keyboard Dancers Holding the clutch all the way down only puts minimal wear onto the throwout bearing, the clutch material will not wear or "heat up" because it simply is not in contact with the flywheel or anything else.
Thanks
Won't a *cross plane crank iron out most of these issues as well? I would assume making the power delivery smoother as well and making tire management a lot better. At least that's the difference I've noticed on motorcycles. Vtwin's and the R1 with its flat plane crank don't kill tires as much as a tradition inline 4 does.
*edit: wrote flat plane initially.
The r1 has a x plane crank.....
vidurc I believe most I4's are flat plane. The term is more commonly used with V8s as they're very distinct differences. Also, flat planes aren't exactly smooth, they have a considerable secondary imbalance: th-cam.com/video/_TssXF8yQek/w-d-xo.html
Engineering Explained I'm sorry I meant to say cross plane. Yes you're right what the CBR's Suzuki's and other brands use is a flat plane setup versus what the R1 uses which is a cross plane setup.
***** Sorry. Yes that's what I was trying to refer to. Got flat plane stuck in my head!
So if a cross plane setup was used, would the imbalances be ironed out a bit more?
Hey Engineering Explained! I was keen to know more about how Gull-wing doors work.
So does does a v6 Also fire every 180degrees or is that just 4 cylinder engines
6 cylinder should fire every 120 and 8 cyl every 90 assuming they are 4 stroke
what are some dual mass flywheel types
Engineering Explained "If you have a 4 stroke engine your'e getting one power stroke for every 180 degrees of rotation." Something seems off. Would you not be getting one power stroke every 720 degrees per cylinder?
I think you're right if it's based on one cylinder, I'm assuming he's saying any one of the cylinders will be firing every 180 degrees.
Andrew Wittwer Whoops, I was referring to a 4 cylinder engine and perhaps didn't clarify.
Engineering Explained so if I have a bad flywheel it's gonna start making noises like rattle flywheel ??
Engineering Explained so now which one you choose between them DMF or SMF ? need answer next Saturday 3/6/2017 I should decide :( !!
When you stall a engine with a DMF you will hear a large bang; what makes the sound?
Wow - that's a great way to test to see if your car has a DMF or not. My Subaru used to do that when I stalled it accidentally... BANG!... There was also a lot of buzzing noise coming from the shifter. Finally the clutch started slipping badly so I had to replace it. Much to my horror I found a burned up DMF inside. Not expecting to have to shell out the money to replace it, I opted for an SMF. It definitely feels different now. If I stall it there's no "BANG!" If I hit the gas too hard while launching and turning the inside rear wheel will chirp. There's also less buzzing coming through the shifter. That seems counterintuitive but I can only imagine that the DMF was smashed on the inside.
That’s the secondary flywheels snapping back suddenly or bottoming out the spring.
DO A VIDEO ABOUT THE AE86 AND WHY IT IS AWESOME :D
It's expensive but it's smoooth
So can you therefore use a clutch plate without springs?
nagonzo I believe this is done, yes.
BMW SAE (Self Adjusting Clutches) with a Dual Mass Flywheel have no springs in the clutch plate if you would like to know.
How viable is this design in performance applications?
It's not, for frequent gear changes a single mass flywheel is preferred as it's lighter and less prone to failure
Generally single mass handles performance driving better. Simpler design that can optimize holding force and hard shifts. But it’s more harsh.
generally mechanical low pass filter..
Very good analogy!
Low pass filter filters out high frequencies , flywheel reduces amplitude, frequency of vibration stays the same. So not so good analogy.
@@barciu11 yea, its more of a dampener
@@barciu11 Low pass filters "reduce the amplitude" of higher frequency
More like a compressor as far as visualization of amplitude 😊
So you can see what the room looks like through the reflection from that TH-cam award thing hanged on the wall.
Sebastian Rosenberg Such a win
Riding the clutch also damages the flywheel
Conclusion:
A Dual Mass Flywheel is a type of flywheel designed to fail permanently and then suck all your money out of the bank. There is one way to prolong its life time. Just don't drive.
My dual mass flywheel just cost me a lot of money
GG
What's wrong with a slightly heavier single disc? Too simple and reliable? Too little parasitic loss?
Long story short, go for the V8.
straight 6's and v12 sound like a much better idea to me. i don't want to pay £800 for a fly wheel. i would rather spend it on maintaining more important parts and killing polar bears :P
Lawrence Timme Yeah, or a Wankel Rotary and a Boxer 4-6-8-10-12 etc.
a V-4 would be another cool solution.
Hazardous-Nebula v4's have no flywheel?
So many 'SOs' in this video.
Load of Bull. The crank is not vibrating. The weight of a solid flywheel and crank webs create a smooth revolution of the Crank.
Dual Mass Flywheel is there for people who can't drive smoothly and lack mechanical sympathy. Ask a driving instructor.
I don't quite get it
If your car has a dual mass flywheel it usually means you’ve got a car with a crap engine.
M54B30 inline 6 is a mighty engine which has DMF.
It is not diesel, it is not for trucks and it is opposite of low cylinder count. - 2:42
so in a nutshell they invented the dmf because they couldnt or wouldnt design the engine to run smooth enough?
Engineering Explained i posted something i thoght of myself on CT and i'd like to hear you opinion on it as an engineer
you know, engineering is all about being innovative ;)
www.carthrottle.com/post/EdMvPu/
bucketslash11 I guess I'm simply unsure of what I'm looking at. What is the idea?
Engineering Explained I think I've figured it out... it seems that he's using a magnet pushing against a magnetic rim on the wheel to work as suspension... there are a lot of practical problems with this that I can think of... the rim staying in the magnetic field for one...
Engineering Explained the rim is sitting on in'wheel electric engine whcih is sitting on a stalk down from the body work (think how the caster angle is formed)
the stalk has a mag-lev at the top of it and a bearing which makes it able to raotate the wheel, it will need this as the steering rack and front wing is removed for reduced drag (will need sensors so ehat each wheel is pointing the same way)
the suspension is moved back to the connection with he body of the car and it should also ave some big guiding pins so that the energy goes into the shock absorber
Engineered to fail and destroy your clutch