Ducati Desmo Valve System
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- เผยแพร่เมื่อ 4 ต.ค. 2024
- The Ducati Desmo Valve System was designed by Fabio Taglioni and is in part responsible for Ducati Motorcycle's spectacular performance. This animation illustrates how the Desmo Valve System works. Solid modelling and animation was done by Bluming Inc, and more information can be found at www.ducatidesmo.com
It is important to say that this system still uses the spring, which is responsible to finally close the valve, but the spring is much smaller and lighter than in the conventional system. As someone already mentioned this system was used in a days when technology wasn't good enough to produce quality springs.
In MotoGP and F1 they use pneumatic springs.
The description should be "The Ducati Desmo Valve System was designed by Fabio Taglioni and is in part responsible for Ducati Motorcycle's preposterous reliability and hefty maintenance costs".
Ducati monster 1200s desmo system is pretty solid. Still very costly
Mercedes had desmodromic valve gear on their formula 1 car before world war II
Thank you for posting this. I've owned Desmos since 1971. Nothing rides like a Duc!!!!
I had two desmo Ducatis in my life. The first one was a single 450cc Scrambler and the second one was a 900cc SS replica.
The valve clearances were fine when checked @20.000 miles in both bikes, but I do know that they need some specialized tools to set them at the right adjustment.
Very clever!This way the engine doesn't get the parasitic effect of having to compress the valve springs.Plus due to the free rocker movement there is less friction!Amazed...
I believe it's more to prevent valve float at high rpm
Just bought an 1100 Monster today. I barely know the bike, but it's damned fun to ride already. Torquey, powerful enough for a sane person on the street, quick handling, light weight. The motor sounds and feels great. I liked the Japanese 4cyl I just sold...it was a great bike. The Duc is in a different category (not better, just different). Doesn't make sense to compare too much.
My old bike had 20 valves to adjust on 4 cylinders. The Duc has 2 adjustments on each of 4 valves - a total of 8.
I love my ducati. wanted one since I was 15 and my dad bought my ninjas 250. I've never owned a car and ride everyday regardless of weather. My new hypermotard has eaten up everything this winter has thrown at it. Maintenance costs are expensive. Which is why most people who own and actually ride their ducatis on a daily basis do their own maintenance. Buy a ducati and once you realize it has a soul that whispers in your ear when your full throttle or a million miles away, then and only then will you understand. 6000 miles since December and counting. :)
I like that! "A soul that whispers in your ear". There is definitely something about Ducati. The clutch chatter is intoxicating music to my ears!
Brandon Goodheart I love my ducatis, traded in my 91 900ss at 196.000 miles, got a 2001 St 2 and turned 195.000 on the old girl today 😄
I have a 2000 model Monster as a daily I ride about 100km round trip to work 5 days a week, and I haven't found the maintenence really any more expensive than any other bike. 50'000km on the clock and it's only needed one belt change, valves have only been shimmed once. Still on the first clutch too, though I may replace it and the springs soon.
Well said! I recently sold my Ninja 300 and bought a Diavel Cromo. Such a lovely brand/bike!
Bought my first Ducati supersport S sometime ago as my first motorcycle, i absolutely love to it to bits. Yes its expensive and might not be that great of a motorcycle but its just pure emotion. Nothing compares to the sound and soul of a Ducati starting up on a cold sunday morning....
Somewhere in the area of London Ontario, in an old barn or basement probably, is a FirePower engine rebuilt to this system. At 12000 RPM, they took it off the bench. No valve float, insane RPM and power. The old fellow who built it was an aircraft mechanic in the RCAF. Don't have much more information, but it was spotted around 1968 by my Father. Dad had some oddball hot rod builds, like the Offenheimer '55 Bell Aire (Idled like a POS) and hung around a bunch of engine nerds and weirdos.
Wow, most of you who made the lovely comments regarding my Ducati Desmo Animation seem to know about Desmo valve system much better than people at the Ducati factory! Why don’t you guys contact the Ducati design team and let them know what to do? Ducati won only 17 Manufacturer’s Titles in the FIM Superbike World Championship in 24 years of the existence. Not to mention Ducati has more wins in the WSBK competition than all competitors combined! (Honda, Yamaha, Suzuki, Kawasaki, BMW, Aprilia)
THANK YOU SO MUCH MIROSLAV !!!!! GREAT JOB !!!
I'm not sure winning on the track relates directly to unreliable expensive to own road bikes.
Nobody's saying its not a great alternative to springs but the facts are there...
Thanks, I've always wanted to see a desmo valve operation closeup.
DUCATI overpower valves , like super charger ❤🔥
Lets all remember one thing. The motors that are used by our GP & Road Racing hero's are not the same as the motors in the production bikes. Yes, some classes use the engines we can all afford, but the higher up you go, the more custom things get. One other thing too, the majority of us are not capable of riding powerful bikes anywhere near their potential without years of experience and even then, many experienced riders come off & worse every year. I have never cared for one brand over the other & as a kid in the 70's, I remember the onslaught of Japanese motorbikes on the streets & the race track. American & European bikes of the day were known for there reliability issues and the Japanese offered a solution. These days, in my opinion, not a great deal has changed apart from the US & Euro bikes improving their game, but one look at the 2nd hand market & the numbers don't lie.
感恩了解，謝謝分享！
Not a fan of Ducati but the more I learn the more I like
verry very best to increase efficiency slightly but effort is 100% work
Hypnotic...
Any form of reciprocation has huge inherent loadings as the motion reverses be it in the valve mechanism or in the combustion process. Rotary systems of course cannot remove the losses brought about by changes in speed but they never even start to approach the inefficiencies of reciprocation. I wonder how good a sleeve valve system might be given current materials and precision?
Oh and I have an 1100 evo on order. GO Ducati
Did u get ur 1100 Evo?
I love my 1100 Evo
OK - SO a cam lifts the piston rather than a spring.
I remember hearing it was solution to valve lash at higher rpms.
This makes sense.
What a cool idea.
I guess some extra head friction robs power but if the timing is more accurate it more than makes up for it.
Very Cool.
Luv and Peace.
Yes but I see kind of inequality in the deterioration of the 2 cams, and not in the good way…
Therefore it seem the solution is to still use a spring but with much less force then the one that would be required without the additional cam
Thanks for the excellent video!
Is it mean there are NO SPRING at all ?
Reduce engine power loss to push the spring valve.
no valve float on high RPM.
These type of valve trains were originally designed because we didn't have the technology to make a durable valve spring and valve springs had to be replaced frequently which was a pain in the ass. Today valve springs can outlast the engine and the problem is non existent.
In order to keep valve lash within spec, because they lack a spring that makes up for wear, they require frequent precision adjustments which are expensive, more so than spring valves, otherwise you start dumping your compression which is your power.
+TrueBlogge777 I believe the Desmo engine closes the valves to within around 2 thou and then compression finishes the valve closure, is this correct.
+Gabriel S.
Perhaps they could have a hybrid design, which does have a spring, but by design, much less energy is lost in the spring. The spring would just compensate for wear ... over the life of the engine, the spring wouldn't move that far really ...
Over 10k rpm no spring system is good enough to move the valves at required rate. And that is the range where race engines mostly operate
@505197 In 1910, the Desmo was realized (however not mass produced) by Arnott, so the system (as a basic 1 cam) is not owned by Ducati; the system that they use on their bikes now (overhead 3 cam) has been patented many times over and is therefore exclusive to Ducati. The first mass production of the system was in 1968 with Ducati Mark 3 250/350. As for the RPM levels, it has nothing to do with the desmo system, hence the reason you didnt notice a difference between the motors with and without.
No valve springs is a new way to do this act. More valve seat life and reduced valve train weight is a plus too.
Man I don't know what marek0086s problem is. its like a desmo system slapped him in the face with a glove or something Valve float IS a problem in high performance engines. And Desmo has proven to be a grate solution to the problem. Ducati has used it since 1956 with great results In my opinion a great and elegant solution to a real problem.
Ducati desmo engines have valve springs as well as a closing rocker - hairpin type, which assists the valve closure. Often overlooked in these diagrams and explanations.
Lots of comments about complexity and valve clearance adjustment etc. In practice the engine is very reliable and you only carry out valve clearance adjustment very rarely. On a 70's single it's easiest to whip the engine out (20mins) and do it on a bench. Re-shimming a cold engine is not difficult.
Since there is no spring can this save a bit of horsepower?
It probably does save some horsepower, but primarely it is very useful for high RPM applications, where it becomes hard for springs to close the valves quickly enough
FUÉ UN SISTEMA MUY AVANZADO PARA LA ÉPOCA, PERO NO SÉ POR QUE COÑO DIO TANTOS PROBLEMAS, Y ERA REVOLUCIONARIO, LOS MOTORISTAS DE ESTAS MAQUINAS, SIEMPRE ESTABAN EN EL TALLER, ERAN MAQUINAS INCREIBLES.
Thats ginious, always thought that the valve where one of the mean problems why engine cant rev super high. But the sky is the limit whit this system!
This was a problem back in the day since the springs couldn't hold up and would start floating. With newer material technologies though, the valve float has been solved. Ducati has stuck to the desmo system though which still has some upsides but now in the modern-day there isn't a huge difference and the desmo system requires more frequent maintenance
As a mechanical, if you see that thing, you think it’s impossible to adjust
He's not entirely incorrect. The internal pressure inside of the combustion chamber is orders of magnitude higher than atmospheric, so that action also helps with valve seating as well. After all, the desmo valvetrain isn't running with absolute zero tolerance at TDCC.
@Spyderd20 Desmo is older then internal combustion is, it was employed on steam locomotives. Ducati didn't invent it nor do they have any claim to any right to produce it. They do not have a stratospheric rpm operating level, so I don't really see any great need fo the complicated system. I've ridden ducks with springs and desmo and they both hit the limiter about 9 grand. You can take some spring engines to way more then that. Bikes typically run higher rpm then the desmo system on Ducs.
What advantage offers this mechanism , why its not simple as a car ??
Dude, read my previous comments. I've owned 3 Ducatis, one of which was a 1098. I love the looks and sound of them, but the maintenance costs make me feel like I'm being robbed. And I don't particularly enjoy that. Plus, I was always unsure when the time came for a bigger trip. So Triumph it is.
Brits aren’t that famous for reliability 😅
triumph is not any better
It would be all too easy to get the impression Taglioni/Ducati invented the desmodromic valve system. From Wikipedia: Desmodromic valve systems are first mentioned in patents in 1896 by Gustav Mees.[citation needed] Austin's marine engine of 1910 produced 300 bhp and was installed in a speedboat called "Irene I"; its all-aluminium, twin-overhead-valve engine had twin magnetos, twin carburetors and desmodromic valves.[3] The 1914 Grand Prix Delage and Nagant (see Pomeroy "Grand Prix Car") used a desmodromic valve system (quite unlike the present day Ducati system).[4]
Marek0086, I have done 100ks with Desmo set-ups and at the most they have cost me $30 to keep sweet. They have never ever dropped a valve, broken terminally, fluttered nor bounced. I have bought 2 shims, run 10 motors and have totally enjoyed the satisfaction of reducing that tiny, minimally power sapping spring to redundancy. The poppet valve is an abomination but this is it's best incarnation in my humble opinion.
Actually, the poppet valve is the very best way of controlling gas flow into and out of a combustion chamber that must operate at very high temperatures and pressures. That's why it predominates in vehicle engines worldwide, and has for many decades.
There are alternatives--rotary valves, which require lubrication on surfaces exposed to combustion gas and are more difficult to seal.
2-stroke engines with no valves, but require direct fuel injection to prevent large amounts of unburned fuel from being blown out the exhaust ports--and there isn't enough time for the fuel to mix with the air before ignition, so the suffer from execessive fuel consumption and higher emissions.
Wankel engines, which also have no valves, but have a far less than ideal combustion chamber shape, so the thermal efficiency is low--high emissions and fuel consumption.
There's a reason why the 4-stroke mill with cam-actuated poppet valves has been the predominant power source for cars, small aircraft and numerous other applications for so long, it's the best way to do it at reasonable cost and with minimum maintenance while retaining highest practical efficiency.
According to an article on Page 18 of the September 2012 issue of Motorcyclist Magazine, Mr. Taglioni did not design this system. It was originally patented by British engineer F. H. Arnott in 1910. The article goes on to say that Mr. Taglioni brought the technology to Ducati when he joined the company in 1955. The system has been used by other motorcycle builders such as Mondial, MV Agusta, BMW and Honda along with auto manufacturers Mercedes Benz, Ferrari, Peugeot, Audi, Toyota and Honda.
@3000gtvr45Lebtt I agree with what you say, and it just reinforces my contention that you don't need a desmo valve train on a low rpm engine, it's just needless complication. I've ridden a Bimota and Multistrada, each seems about the same to me and one has springs. Neither was a high winder compared to other bikes. I believe if you do the calculations of piston speed, near 90* BTD/BDC, rod angularity plays a role, the piston mph will be a lot lower then one might think.
it would seem like any gains in precision (over a valve spring) would be offset by both the need for eventual adjustment (due to valve and seat wear) and the fact that you are adding rotating mass.
Does the spring not put almost all of its energy back into the system pushing the valve back up?
good question - yes it would, but I suspect the engine would be much better off without the resistance of the valve springs.
The design was intended to reduce valve float issues, not resistance in the powertrain. I like the system mostly because the head has a ginormous, expensive pair of bevel gears mounted on it.
due tempi!!!!!!!!!!!!!!!!!!!!!!!!!!!!1 forza
Valve intervals are a lot shorter, but there aren't a great deal of reliability issues due to a result of the Desmo valve system. Italian electronics and other bits are what's a pain in the ass.
Yes, a friend of mine bought the Panigale and the screws that tighten the motor would always loosen, the garage could never solved the issue…finally he bought a BMW R 1200 GS 😅
Do they use this in there go bikes ? And is that why they can rev so hard
the actual advantage is that u can rev higher without a spring which can get to its resonating frequence.
increased valvetrain weight, more lubrication required, no vtec like option possible because there would not be enough room to do it meaning your valve profile stays steady... still it's a good idea if you ride at high rpms a lot.
G Clarke Incorrect, Ducati already has the Testastretta DVT engine. VVT is already here.
got my 1098 Streetfighter S serviced recently and the cost wasn't as bad as people make it out to be. my old 2 stroke 250 Suzuki cost me more to service.
the rpm limitation is made by 1- valve floatation 2- the limited rigidity of the engine structure,those are the main issues, since the desmo valves doesnt suffer from floatation, they can rev more, that means the desmo valves DO incide on the max amount of rpm! the spoon engines are built to be mutch more stable on the crankshaft, and they rev up to 10 000 rpm thats the secret,not the pistons mass ecc...
desmo wow
“If I was in another brand probably I don't use the desmodromic system because this is a system that has a lot of potential, in my opinion, but it is quite complicated,” Dall'Igna admitted. “So if you do not have the knowhow to do this it is quite difficult. But we are Ducati. Ducati has a lot of experience with this kind of system and in the end I think this is an advantage in comparison with the other solutions.”
Ducati's rivals - Honda, Yamaha, Suzuki and Aprilia - all use pneumatic-valve technology rather than the trademark, mechanical system at Ducati.
“In my opinion we have exactly the same advantages as the pneumatic system, but at low rpm the friction is a little less. The overall performance of the engine I think is better [with the desmodromic],” Dall'Igna declared.
I'm with you on the visual and accoustic appeal. That's one of the main reasons I've had not one, not two, but three Ducatis. I started with a '00 Monster 750, than I had a '05 S4RS and finally a '08 1098. I spent ridiculous amounts of money on maintence. Let's face it: Duc's valve system is prehistoric, and Ducati keeps it only because of its high maint€nanc€. I've been riding a Speed Triple since April '11 and it's been an amazing experience. Let's see if Audi infuses some common sense...
Prehistoric ?? Are you serious ? How can you say this ?
@@Sanchodecuba69 Cause it was designed in the 50's to deal with high RPM valve float due to the spring technology of the time. The springs have vastly improved since and everyone else has moved on Except Ducati. Oh wait... they're using valve springs in their multistrada V4 now too...
RPM No limit😎
I hadnt adjusted te vlve on my duc for good 15 k..when I finally did this year the mechanic said I coyld have done without valve check. ..so dunno what you people are bitching about...own a duc first!
Krasimir Dragomirov I guess as long as the valves don't seat differently than new it is an almost perfect design. Does Ducati recommend the amount of kilometers you should check the valves? Do they provide you with any information about different services you have to do compared to stock?
Im curious, its a really cool design.
+Shikamoo P.K. Every 15,000 miles they recommend getting valves checked
And 7.5k miles for belt change!
I believe so too. The desmodromic valve system isn't an innovation by Ducati or it's assigned designers or engineers such as Taglioni. The valve system in my belief above came from someone else such as stated above. It was just a matter of someone (i.e. Ducati) developed it and making good use of it today.
Just like the Wankel aka Rotary Engine, originally conceptualized designed by Felix Wankel, but has been developed and now put to good use by the Japanese car manufacturer Mazda.
It exists since 1920!!!!!!........
Why not use a torsion bar as for the spring like effect on a valve?
Because torsion bars only have a single zone (where bending occurs) where the maximum stress is generated during compression, whereas in a spring, the stress gets distributed across all the areas due to the coil like geometry. Hence, torsion bars are more prone to strain and lose elasticity quicker than a spring.
a spring is technically a torsion bar, just curled up
The Honda 450 had torsion bars, but the difference between them and coil springs was negligible.
So..no valve springs at all? That's brilliant. I wonder why they don't use that system in F1 etc? Anyone?
Google desmodromic valeactuation - Not a Ducati idea but a good one.
marek seems to forget who won how many SBK titles with this system that DOES not use springs other than one to keep the rocker where it should be. Watch a video on how to adjust these systems - one spring and it does not control the valves at all.
Thats not true. The valve is kept closed by the lower rocker arm and the 'closer' cam.
because with f1s they have fancy springs that work better than the desmo system
so theres no need for the desmo system and not to mention its a pain to fix things on the desmo system
@joknrok Mainly because Ducati owns the rights, I presume. Cool trinket, though. Expensive and time consuming as hell to maintain, but a world class bike "right out of the box" given the closeness of the stock to racing models... I want one. Not gonna lie. Ducs pwn.
Apakah itu tidak menggunakan pegas?
Why people keep on comparing this valve design vs motogp winning stats? Motogp had never been about making the highest horsepower figures. You need a perfect balance between engine power, chassis and electronics to give you the fastest time set around the corner and straight line. Anyone would agree that Ducati got the highest horsepower figure due to it's freaking Desmodromic valvetrain, correct overall engine design and metallurgy choice. Ignorance will disagree with me. Second, why would you compare a 2 cyclinder engine with 4 cyclinder of a same displacement. Their CFM value are so dif. And offcourse desmodromic system aren't as good as a current of conventional valvespring system in terms of reliability and low rpm application (it just a ducati's marketing gimmick) but you can't simply ignore the fact that it surpassed any valve spring system once (of course depends on size of an engine as bigger engine carry more reciprocating mass) engine pass 14k rpm. Not all racing technologies are applicable to a normal street bikes (if this statement is a BS, then everyone will go with a pneumatic valve) but under certain real extreme condition you will gain a significant adv. compared to a conventional street use application.
Desmodromic is second to pneumatic valvetrain that everyone else uses
Perché non fare la fasatura variabile così diventa un desmo-vtech?
2023 and still not using bearing ?
Does these valves require shims if you actually need to adjust the clearances?
+alimacdee Yes they have shims.
Hmmm.... that would certainly help eliminate valve float at high RPM... now to incorporate this idea into an American V8 roller cam...
THis design will quickly wear out since rocker arm has direct friction contact on the valve tip. Also the animation doesn't show weather upper and lover valve neck are connected, but if they are this will add great stress to the closing and opening cam. I think this desing will not last long.
this is few decades old test and true design
it eliminates a valve floating on higher RPM.
b novak It's been around in Ducati's since 1975, it's more than proven itself.
eliminating the spring, how much does this translate in power and fuel economy?
Bu valf sistemi yüksek rpm çevirmek için geliştirilmişti
Why not just use a crank on the valve?
maybe lubrication issues...
qwertz33 All it would need is a small jet of oil like many other valve systems.
Due to sealing issues with the valve as using a crank and rod setup would mean that the valve would need to be mounted slightly off-center relative to the rod to prevent seizing.
the problem is that you would not only have an up and down motion alone but rather a linear motion superposed with the slight back and forth rotation of the valve.
A crank doesn't have a delay anywhere in it, the valves would always be opening and closing, not staying closed during the compression stroke like the cam system does. A crank style system you would need some sort of secondary action where halfway up or so the valve stops and the crank still spins, there are many ways to do it but i'm not sure they're any less complex or long-lived than this setup.
this is for a drag engine, your average turn key driver aint going to want to lash the valves every day. valve springs are compresed as a pre payment of the energy used to close the vave that is being opened.
Works in theory, but in reality it just makes the maintenance costs ridiculously high and reliability not that great...
Okay... You and the presentation I have to make inspired me to look this up. Turns out they DID use it on cars... First, and a long time ago.
wikipedia(dot)org(slash)wiki(slash)Desmodromic(underscore)valve
teamyikes(dot)com(slash)desmo
all fine and dandy until maintenance time comes........whoops, there went my pocket book............and if you sikip it, well you better have two pocket books.
twcaldwell1951 When the last time you had a dealer do your Desmo valve adjustments?
rotary engins are great norton showed this
Hey where'd my apex seals go? Oh well time for another rebuild.
I don't know about the advantages or disadvantages of this system. But I do know that if I was to get back in to motorcycles then it would have to be a Ducati. Maybe Japanese are technically superior, but they are not beautiful or soulful like a Ducati.
Ｓｐｌｅｎｄｉｄ．
Don't act like you animated more than one rotation.
The excellent, small, superb power-weight ratio Wankel is used in helicopters. Mazda are to use it as a range extender in hybrids, which will outdo piston engines. That is where the market to moving.
Not motorcycles matket. Wankel motors are simply ugly creatures.
the other can imitate this
elimination of hi rpm valve float is the only reasone you would put up with wrenching on the motor every day of the week .and fact is no matter how its done the engine must use energy to make the valves move up and down . even the deflection caused by rpms would put this system out of adjustment.
Ducati desmotronic
That's what's missing
Ducati appears to go against a very basic engineering principle
KISS.
@NH3R717 i guess it's called "a joke."
but that's ok.
Скажите как клапана прежымаются к седлунапример когда износ того вала или клапан от времени его сильнее нужно прижымать как это реализовано
i hate this complexity, so that always choose a 2 stroke engine.. yeah i win
nurfaikham haiqal until you get a 2 stroke detroit diesel engine. then you you have 4 exhaust valves!
+Normalguy35
LMAO, you read my mind! ... XD
why idiotic?
two cam lobes for every valve, fuck that. and how do you adjust when it wears?
The top of valve stem mates up with a hydraulic tappet, I imagine... or shims.
shims and hydraulics. of course.
Looks like a v-tek cam..
This shitty system is the responsible of your constant valve check/clearance every 15000 miles or less and very low performance compared to the rest of Japanese sisters.
Source: 17years experience Ducati technician
Forgot to mention Source: born and raised in Italy racing with Ducati motorcycles
Definitely. There are only 2 Ducati that can compete against Japanese 1`Panigale 2` Superleggera but hey would you spend $65000 to have "standard" specs but made in Italy?
:)
Cazzoz Duroz desmosedici rr
Kawasaki H2R, ninja zx10r 04,zx-14r ...gsxr1000...Ducati is a disposable toy compared to these mechanic monsters
Cazzoz Duroz
agree...the desmo system is by itself actually a good idea...but it solves that famous problem that..we...never had?! i mean, as an engineer myself, i absolutely hate when someone try to re-invent the wheel...we never had problems with valve springs, so just leave it alone..