Valvesprings, A Thing Of The Past?

[Nightmist66]

Here are some videos I saw a couple years ago where a new system is being tested without using valvesprings.

https://youtu.be/GXIdOTkJhEY

https://youtu.be/inrBHHVVfng

https://youtu.be/LJFj6FuKRwc

I believe there was experimentation of pneumatic valves in the 70s or 80s.

[cjshaker]

It might be closer than you think. I've watched Koenigsegg from the beginning and they've been working on this concept pretty hard. They have a running example in an off brand car so he's obviously serious about trying to incorporate it into their high performance cars. If they make it work then it will change the game for most manufacturers in the future. This video shows the concept and the real thing. https://youtu.be/Bch5B23_pu0?t=50s

Edit to add that Koenigseggs cars are "supercars" that use high turbo boost pressures. I would think that turbos and varying boost pressures might play havoc with an air valve system. But at the rate computer controlling is advancing, who knows.

[jayb]

Desmodromic valvetrain systems have actually been around for a long time, and in fact were mentioned in a patent in the late 1800s, according to Wikipedia.  Its an old idea but a good one.  However, I'm not sure anyone has ever made a system that can rival a good valvespring system; I wonder if they're used on any professional race engines, like F1 for example?

Pro Stock Paul advertised "air cup" spring systems back in the 1980s; not sure if they worked, and I don't know anyone who has used that setup.

[Barry_R]

Desmo stuff is used in a couple hard core motorcycles (Ducati comes to mind) as a production item.

F1 used to run a nitrogen filled cylinder instead of a valvespring, with a "make-up" supply carried on board in a small tank.  Not sure if that is the case anymore.

When it comes to making maximum horsepower in a professional racing environment RPM is the King, and valve springs are the Devil...

[ScotiaFE]

When F1 had basically unlimited RPM and 20K plus crank speed they all used a pneumatic valve system.
Today with the limited crank speed for the new "Power Plant" I would say they are still using the pneumatic
system, but no doubt it has some Flux Capacitor components in there.
And us mere garage monkeys are not getting a good look under the covers.  

[machoneman]

Yes, all the F-1 engines for some years have used pneumatic springs. Race bikes too and some other applications. I don't think any of the supercars use them however and that likely has to do with longevity and/or the need for regular maintenance. I do remember one F-1 engine supplier (Renault?) testing a desmo system in the 70's or 80's but it never panned out.

https://en.wikipedia.org/wiki/Pneumatic_valve_springs

[Katz427]

A few years ago I got to see a system developed by an oem supplier ( I believe it was Mahle) that used solenoids to actuate the valves. I thought this would be the "hot" setup at the time. At an SAE meeting the oem's were working with a committee to develope a standard for 42 volt systems. The valve train and computers performed better with this voltage. At the supplier I worked for, we were planning for a switch to the higher voltage. Then nothing. What happened? Later I heard the valve system could not meet noise requirements acoustic and it also required a fair amount of shielding for electrical noise as well. I guess little coil springs, cost a lot less and no emf.

[WConley]

The air springs have a very short life, so they've never made it beyond race engines.  Until the the high rpm electromagnetic valve actuators come along, we'll have to live with the valve spring devil!

FYI some of the big MAN diesel truck and marine engines have gone to electromagnetic valve actuation.  They turn slowly enough though that it works with today's technology.  Koenigsegg is the guy investigating this technology for high-revving supercar engines.

[shady]

Ducati has been using them for years on 2 & 4 valve heads. Pretty much bullet proof. I had a Monster for a while, twin "L"  2 valve & was good to 10K. only drawback was Duc wanted you to check lash every 5k miles. Kinda complicated, was done with buttons, & expensive if a dealer did it. never checked mine, just pounded it & eventually sold it. It was hands down the best sounding bike out there.

[WConley]

Ducati has been using them for years on 2 & 4 valve heads. Pretty much bullet proof. I had a Monster for a while, twin "L"  2 valve & was good to 10K. only drawback was Duc wanted you to check lash every 5k miles. Kinda complicated, was done with buttons, & expensive if a dealer did it. never checked mine, just pounded it & eventually sold it. It was hands down the best sounding bike out there.

I'm pretty sure Shady means a desmo valvetrain.  I have a set of Ducati heads on my bench and I have ridden some of those sweet machines.  Yes they are a bit of work to get set up properly, and the MotoGP / World Superbike racing series have shown that there's no real advantage over good quality modern design valve springs.  Still those heads are works of art!

[BruceS]

Bill,
Doesn't the Ducati desmo system use springs as an assist to the main desmo mechanism?

Bruce

[Nightmist66]

Pro Stock Paul advertised "air cup" spring systems back in the 1980s; not sure if they worked, and I don't know anyone who has used that setup.

I have a copy of his catalog that shows them. Don't know how well they worked either.

I did also know that F1 has been using the air cups.

[FE Jonny]

Cadillac played with electric solinoid operated valves recently, the technology is right around the corner for variable lift, timing and controll completely by computer controll. The end result will be optimum timing and valve controll at any rpm or load. Just as engines went distributorles engine will go camless soon.

[WConley]

Bill,
Doesn't the Ducati desmo system use springs as an assist to the main desmo mechanism?

Bruce

Bruce -

There are light "helper" springs on the Ducati valves.  (The ones on my heads are "rat-trap" torsion springs.)  This is because the Desmo system needs to have a small clearance in each direction, preventing the valves from being held firmly against the seats.  The valves wouldn't seal against the seats at idle, and the engine couldn't be started.

At higher rpm the springs really don't do anything.  The momentum of the valves throws them hard against the seats, with the springs tagging along for the ride.  What a sound those bikes make!

- Bill