Yes I'll bet: first you need a pump, which of course has to be driven, so a drive arrangement. There is the necessary plumbing and of course the "springs" themselves and their associated fittings.
I should like to know the likely life of these components - in road car applications.
I recall that Renault designer Dudot when asked what happens if the system fails, replied: "Simple, the pistons will close the valves!"
The only system I have seen close-up is from the Ferrari 049 engine, so 2000 technology. For road car use you might need a pump, but as far as I know F1 systems use a bottle to maintain pressure as there is some loss, but I don't know how much. The 049 cylinder head is full of airways cast in situ, and drillings. There are three small, complex (expensive) valves for each combustion chamber - that just might be three inbetween pairs of chambers - and a sealed spring unit for each valve. The precision involved in making these parts is way beyond what you need for steel coil springs I would suggest, and the whole shooting match is just not necessary for a road engine. The last versions of the Honda CART engine was, I think, run up to 16,000 RPM on steel valve springs - why bother with anything else?
Illustrations to follow if I can find them!
Basic pneumatic valve spring system.
Cutaway showing one pneumatic valve spring and the positions of three valves, indicated by red lines. The two on the left are from one group of three, the one on the right is one of the next group of three - they are situated on each cylinder centre line, the two on the left being accessed/ inserted via the spark-plug bore.
The valves, floating in mid-air, but in their correct relative positions.
Edited by Tony Matthews, 05 May 2010 - 16:51.