F1technical.net

Why there are not cvt gearboxes in F1???
They are more efficient than normal gearboxes that they use today!

Cause they're illegal!

mhm..tnx

ARTICLE 9 : TRANSMISSION SYSTEM
9.1 Transmission types :
No transmission system may permit more than two wheels to be driven.
9.2 Clutch control :
All cars must be fitted with a means of disengaging the clutch for a minimum of fifteen minutes in the event
of the car coming to rest with the engine stopped. This system must be in working order throughout the
Event even if the main hydraulic, pneumatic or electrical systems on the car have failed.
In order that the driver or a marshal may activate the system in less than five seconds, the switch or button
which operates it must :
- face upwards and be positioned on the survival cell no more than 150mm from the car centre line ;
- be designed in order that a marshal is unable to accidentally re-engage the clutch ;
- be less than 150mm from the front of the cockpit opening ;
- be marked with a letter "N" in red inside a white circle of at least 50mm diameter with a red edge.
9.3 Gear ratios :
9.3.1 The minimum number of forward gear ratios is 4 and the maximum is 7.
9.3.2 Continuously variable transmission systems are not permitted.
9.4 Reverse gear :
All cars must have a reverse gear operable any time during the Event by the driver when the engine is
running.
9.5 Torque transfer systems :
Any system or device the design of which is capable of transferring or diverting torque from a slower to a
faster rotating wheel is not permitted.

Isn't one of the stated goals of Formula 1 to pioneer technology? I understand why we ban, restrict and regulate technology, i.e. to reduce speeds and costs, but the development of CVT could be incredibly important to the passenger car manufactures.

I assume development cost was the reason for the ban.

Insight, anyone?

Great site, by the way.

From my experience, CVT technology works for lower powered applications, like snowmobiles. At the power they run at (usually under 100 HP) frictional and heat issues are not great, and can be either ignored or easily worked around.
But when you're suddenly asked to work with a CVT that has cones and belts, heat and frictional losses get high.
In snowmobiles, the engine pulls the belt, and the receiving component on the transmission deals with tension. Also, the belt is basically a rubber fabric with cords. But maybe this just won't work on high power applications. I read once that for higher powers, one company tried metallic belts, and that instead of using tension to transmit power from the engine to transmission, it applied compression. To me, CVT's need a lot more engineering and hard work and time to mature. And in F1, you aren't allowed ten years to develop something, you have to win, or do well now.

The company that tried the metallic belt is LuK. But for some reason (cost?) they never used it. What could fit well for f1 is the toroidal cvt, instead of belt. Thou I don't know how developped this technology is.

Isn't one of the stated goals of Formula 1 to pioneer technology? I understand why we ban, restrict and regulate technology, i.e. to reduce speeds and costs, but the development of CVT could be incredibly important to the passenger car manufactures.

I assume development cost was the reason for the ban.

Insight, anyone?

CVT was banned, i think because it took too much of the driver element away from the driving. Fully automatic gearboxes even though they take the driver out of the gear shifting equation, still create the jerk in the car (the slowing down and speeding up...it changes the weight balance of the car by shifting the weight of the car from front to back). With CVT the driver no longer has to worry about the car's balance when accelerating out of bends and especially when downshifting and braking for corners.

That said i may be wrong...the FIA have been known to ban things for no good reason before (Lotus 88).

How they can afirm it is a CVT or not? Is there a minimum RPM drop between gear changes? Is there a minimum time interval between gear changes?

There are FIA stewards dealing with technical regulations. If suspected any part of the car can be dismantled after the race and finding CVT would mean instant disqualification from whole season if not for next several seasons. In brief, no one would risk all investments in building something that is not a loophole but highly prohibited device for so many years.

Williams tested a CVT car at Silverston in the early 90's I think Damon Hill was driving and he commented that the constant red line RPM was annoying

Williams-Renault F1 CVT expérience

David Coulthard was testing this car equiped with Williams-Van Doorne CVT in 1993 and had very good results.
FIA banned CVT from F-1 in 1994.

Oops!!!! You're right it was David Coultard

Nice pic of williams' active suspention!!!!

I just read a magazine article which gave a broad description of a CVT that Toyota is working on. Although CVT's are banned, this is a neat solution in getting rid of the slipping cones and belt.
Between the engine and rear differential, a planetary gear is installed.
http://auto.howstuffworks.com/gear-ratio4.htm
Just one gearset, and the interesting twist is that the planet carrier is attached to an electric motor, instead of being fixed. By varying the speed of the electric motor (and thus planet carrier), the final gear ratio is altered.