valvetrain belt driven?

[ACRO]

hi!

is the valve train of a modern f1 engine (lets say over the 10 years) normally belt driven oder do they use other techniques do manage it? (i quess no chaindrive since the revs are too high)

thanks very much for any information

[zac510]

Gears!
Can't find a very good pic at the moment but if you look closely at this illustration you will see it:
http://www.forix.com/8w/engines/dfv-draw.jpg

[ACRO]

thank you very much for the quick info and the pic. this seems to be an older v8 but it make sense that they keep it until today to prevent a belt failure.

best regards!

[zac510]

Yes it's a much older v8. I understand that the gears where a lot due to vibrations and what not but they're replaced regularly as F1 engines have a much shorter service life than road vehicles.

[Belatti]

I understand that some F1 valvetrains are or were electro-pneumatically driven (with that you dont loss HP while moving valves)

http://scarbsf1.com/valves.html

Others are gear driven (you can see the gear in this BMW V10)



Or this Ferrari engine drawing at the top of the collage and the Asiatech engine pics at the bottom:

[Project Four]

Hi, I do believe that the valve train is gear driven by a series of gears from crankshaft.

Pneumatic valves only replace the valve springs.

[manchild]

Renault RS01 V10 from 1989 also had belt driven valve train

[ACRO]

gentlemen, thank you very much for the further informations and pictures. geardrive seems to be the common way in nowadays, the beltdrive at the 89 yamaha is very interesting too.

very interesting also the cutaway of the ferrari as well the picture of the bmw engine. i guess its the 2000 bmw engine, right?

best regards!

[Belatti]

Hi, I do believe that the valve train is gear driven by a series of gears from crankshaft.

Pneumatic valves only replace the valve springs.

You are right, my mistake

Pneumatic systems use conventional cams operating the valve (4) via a shim\bucket or finger follower, the valve spring pocket is replaced with a chamber (28) pressurised with nitrogen (held within a cylinder in the sidepods) that runs at a constant pressure to return the valve when the cam timing retards.

Maybe I was thinking about this:

What Renault have is an Electro-hydraulic system, where two pressurised circuits operate the valve (16). Valve return is still handled by the pneumatic system (52, 20), but the opening of the valves discards cams for a hydraulic circuit (50) controlled by a electronic valve (58). As this system can use high pressure hydraulics already on the car to operate the valve at the required RPM ceiling, the system seems almost too simple..! Infinitely variable valve timing plus the loss of the reciprocating weight of the cams and drive gears makes this an enticing solution. This solution has yet to race or to my knowledge even be tested in a car, Renault have admitted that as a broader automotive organisation, that this systems has been tried.

And messed my head up!

[riff_raff]

Spur gears are more accurate, efficient, compact, and durable for the conditions an F1 engine runs at, but they are sensitive to torsional vibration. Most high-end production engines use roller chains, because they are strong, durable, quiet, relatively efficient, and provide some measure of vibration dampening. Low cost OHC engines typically employ toothed belts, because they are quiet, have good dampening characteristics, require no lubrication, and are cheap. But unfortunately they are also less efficient than gears or chains, take up more space, and have significantly shorter life spans.

All three drive systems (gears, belts, and chains) have been employed on F1 engines, at one time or another. Current engines though, universally, employ gear drives.

[kensukei]

F1.07
BMW P86/7 engine
Type: normally aspirated V8
Bank angle: 90 degrees
Displacement: 2,400 cc
Valves: four per cylinder
Valve train: pneumatic
Engine block: aluminium
Crankshaft: steel
Oil system: dry sump lubrication
Engine management: BMW
Spark plugs: NGK
Pistons: aluminium
Connecting rods: titanium

F2007
Type: 056
Number of cylinders: 8
Cylinder block in cast aluminium: V 90°
Number of valves: 32
Pneumatic distributionTotal displacement: 2398 cm3
Piston bore: 98 mm
Weight: More than 95 kg
Ignition: Magneti Marelli digital electronic injection
Magneti Marelli: static electronic ignition
Fuel: Shell V-Power ULG 62
Lubricant: Shell SL-0977

Designation: Honda RA807E
Displacement: 2.4 litres
Configuration: V8, naturally aspirated
Vee angle: 90 degrees
Maximum power: More than 700 hp
Maximum revs: 19,000 rpm (as limited by regulations)
Valve train: 4 valves per cylinder; pneumatic valve system
Injection system: Honda PGM-FI
Throttle system: Electronic hydraulically-operated system
Ignition system: Honda PGM-IG

check the database here in the all cars ever section

this pneumatic system is much more efficient than any other, because of low wear and high precision

[manchild]

Welcome to forum. Those are just pneumatic valve "springs" not pneumatic driven camshafts. Such system is in use over 20 years.

[millerjam]

Just out of interest is the info mentioned on Scarb's pages regarding the electrohydraulic renault system from a patent application or was such a system in development by Renault?

[riff_raff]

kensukei,

"this pneumatic system is much more efficient than any other, because of low wear and high precision"

Actually, a pneumatic spring will be far less mechanically efficient than a metal coil spring for most engines. This is due to the gas compression/expansion cycle losses in the pneumatic cylinder, and friction losses in the sealing mechanism.

The reason a pneumatic spring is advantageous in a high-speed engine valve train is that it has less inertia (it's lighter weight), it is inherently self-dampening (undamped linear vibration modes in metal valve springs can significantly increase stresses), the pneumatic spring rate can be actively varied with regards to engine speed (providing a significant reduction in friction loss of the valve train), and a pneumatic valve spring is impervious to fatigue (unlike a highly stressed metal valve spring). In fact, the typical helical coil, compression valve spring is the most highly stressed component in any piston engine.

Unfortunately, pneumatic valve spring systems are somewhat unreliable and expensive to manufacture, so they are not used on production engines.

[manchild]

Here's RS01