I think we are speaking at cross purposes. This is my understanding - if someone knows better, please correct me. The FIAT "MultiAir" (and "Twin Air") system has been sold only from 2011, and is totally different from the system used on various FIAT and Alfa-Romeo models from 1985 onwards. The MultiAir system is the one which interposes a sealed chamber of oil between the cam and the valve. Some of the oil pressure can be allowed to escape, under fine electronic control, thus reducing the valve lift by variable amounts at various points in the timing cycle so that timing, lift and duration can all be varied within limits. The old system is the one which only varies the phasing of the (inlet) camshaft rotation, more like the VW/Ducati system. MultiAir is much more sophisticated, but I cannot see how it could be adapted to desmodromic valves, even leaving aside the question of the FIAT patents.
Ah ok, i made an assumption right back at the beginning that it at variable valve lift also which it doesn't. shame they couldn't incorporate that also. but your right how can they with desmodromic valves. Hmm, they would need to incorporate some kind of hydrolic ram on the valves, which would save a fortune on service operations also. dont think it will be doable with the desmodromic system.
The FIAT MultiAir system has the incidental benefit that there can be no question of the valve clearances wearing out or requiring adjustment, nor of there being any rattling or lashing of valve clearances, because hydraulic tappets are inherent in the system. The new Ducati DVT system however must still require valve clearances to be shimmed just as accurately and frequently as before.
The thing is though all the latest bikes don't seem to need shimming now even when scheduled to be,not like the old days
Not necessarily. There is the possibility of camless engines, with valves opened and closed positively by electrical, pneumatic or hydraulic means instead of by cams. Variable Valve Timing would be a by-product. Many firms have been working on this for decades, but nothing has reached production yet. FYI this link is to a Swedish thesis which is mainly about experiments carried out using pneumatic valves in a Scania diesel engine, but the writer incidentally gives a lot of background about various types of valve mechanisms. http://lup.lub.lu.se/luur/download?func=downloadFile&recordOId=1218737&fileOId=1218738
cool will give it a wee read later,i believe they are well on with electrically operated valves also which might be more appropriate with high revving engines . cheers.
wow, that was just like being back with fiat, seems like i was always having to study something. just goes to show there is very little new out there, just materials and application. some good reference points in there also.
One of the Italian mags has a spy shot from testing yesterday. They claim not only the engine will be different, but the styling cues will be more aggressive (?) over the current model.
They use a camshaft to open the valve, but the closing spring is in the form of a pressurised pneumatic capsule instead of a metal spring. So no, not really.
