Edit: i just realized i posted into the wrong forum >_<

For anyone who doesn't know what these are:

Its basically technology first developed by Renault in the 1984 for use in their F1 engines. They're basically little air canisters that replace the valve springs because the PVSs are capable of closing the valves faster than physical springs can. The advantage of this is that it allowed engines to acheive higher revolutions without the risk of valve to piston contact. Eventually, PVSs became standard issue for all F1 engines.

The only downside to this system that i've found is that even in modern F1 engines, PVS still have leakage problems. If the PVS loses all its air pressure then...just imagine someone removing your valve springs while you're driving, its bad news bears :( . So what they have to do is mount an external Nitrogen (which is what they use in the PVS since it doesn't expand/contract as much as oxygen does to changes temperature) which is tapped into the PVSs to insure that they maintain their pressure. So i would imagine that in order to keep this system in good working order, you'd have to constantly refill you NO2 bottle. Which, impo, is a very small price to pay.

This system is actually not that high tech, seeing as it was developed in the 1980's and now F1's actually already testing out hydrolicly controlled valves...which i take as them saying that PVSs are dated.

My question now is, how come we haven't seen this technology in any production vehicle? I mean, Ferrari damn near puts their F1 gearbox and drivetrain/traction control derived from their F1 cars, how come they haven't even tested PVSs? I'm pretty sure the ppl who pay a quarter mil for their car couldn't care less if they had to go refill a gas bottle every now and then in order to have a car that puts out over 300hp per liter. And who would care about such a small burden once they hear a car scream past at over 15,000 rpm or 16,000 rpm or maybe even 19,000(i know this is highly unlikely but bare with me as i dream :D )? Its not like they can't make that streetable with engine technology advancements with variable valve lift and timing control (this would allow them to have a cam profile that allows the car to idle and start on its own and then another to actually make power in the top end. Having a system like BMW's Double VANOS or A-VTEC would allow the engine to adjust its cam profiles to take advantage of the higher revs without sacrificing (much) streetability.


wouldn't that be a riot of a car?

 

Nice thought, but I'm sure that a lot of Ferrari drivers barely know how to put fuel in their cars, let alone having to fill up the N2 bottle from time to time. Many people buy them simply for the image, so reliability IS a factor...

That being said, Toyota showed a few years back valvetrains with magnetic actuation, both opening and closing, so you would have infinitely adjustable valve lift and timing... Much as I hate to acknowledge that Toyota did something really really right, that's promising technology for the street!!!

 

I've never heard of Toyota's magnetically actuated valvetrain b4, but i can imagine that it must've been pretty amazing. But I don't think they're going to be persuing that very much further considering the F1 cars are going to adopt a hydrolically actuated valvetrain with the same infinitely varying valve lift and timing :D

I don't think ppl buy Ferrari's and expect a huge amount of reliability...seeing how they're track cars and will probably blow up after 30-40k mi XDDD. ppl who own ferrari's can hire ppl to fill up their N2 bottles...if they can't afford that, then they shouldn't have bought a ferrari :P