I'm new to engines. I first got really really interested in them about a year ago when I bumped into this very thread. At that point I realised how little I knew (I knew nothing back them and I know pretty much nothing today). So I decided to learn about them. Fast forward I've been trying to learn about the topic (engines in general) for the last 6 month. I have keen interest in pneumatic valve spring because they are the main enablers of the high engine speeds we saw back in the day. I came across this video and thought about this topic.
A couple of things caught my attention.
1-Variable pressure base on rpm mapping (low pressure at low rpm (9.000 - 10.000 rpm) and higher pressure as the rpm rise by increasing the pneumatic pressure...bleeding pressure off as the rpm reduces). By the way, not entirely relevant but, what would be the idling speed of the v8 and v10 (ballpark numbers)!?
2-They had an on board compressor (on board compressor-reservoir bottle-fill injector-return injector)
3-Not sure if my assumption is correct, but are they using air in the system!? It they are, I wonder how easy it was to keep the target pressure in the system.
Cosworth system used nitrogen, right!?
With regards to the pressure, I have heard about 200bar in the reservoir bottle and 10-20bar in the cylinder/system. Does anyone have more reliable numbers!?
Can someone explain me how the cosworth system works, architecture, etc!? It would be very interesting to see how the pneumatic cylinders are integrated in the system and how they go about things like filling the cylinders with nitrogen, how are these connected to the reservoir bottle, etc.
Also Brian.G do you have perhaps an air drilling/passage map that you could share with us!? To be honest I don't completely understand the system. I have read your post and the honda papers (Honda R & D 2009 technical review) a couple of times (there you have all the schematics, configuration, section views, etc) and yet I don't fell like I fully understand the system.
By the way, this document (Honda papers) also provide very interesting information on the topic. In 2008 they used a 570 cm3 carbon bottle. The system incorporated an air bottle filled with high pressure air and two regulators to supply pressure and discharge pressure. They don't mention nitrogen at any point.
I think Honda papers also mentioned the use of PTFE seal. Last but not least, the paper also talk about the control of the system.
Moving on, another thing that I have heard is that for every 1.000 rpm you get a power increase of 5-8%. Are these numbers correct!?
Sorry for such a lengthy comment and also if any of my questions sound dumb. I would rather ask a question and look fool for a minute than not asking at all and being a fool for life!
Are pneumatic valve springs still used on F1 hybrid engines which run at lower RPM?
Pneumatic springs allow higher lift and higher valve acceleration so there is an advantage for engines of any speed. For an engine with 266 cc/cylinder @ 15,000 rpm, there is a big advantage in pneumatic valve springs.
