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Hi, for my mechanical engineering senior design project, we are looking into pneumatic valve springs. I have been searching all over to compare pricing, options, and whatnot, but haven't been able to find anything. Does anyone know of any companies, websites, etc. that sell these? Any and all help is very much appreciated. THANKS!

meproject wrote:Hi, for my mechanical engineering senior design project, we are looking into pneumatic valve springs. I have been searching all over to compare pricing, options, and whatnot, but haven't been able to find anything. Does anyone know of any companies, websites, etc. that sell these? Any and all help is very much appreciated. THANKS!

I don't think there are really any "off-the-shelf" pneumatic valve return systems available. F1 cars use bespoke pneumatic systems. You could try http://www.numatics.com

The way I understand the pneumatic valve-systems, there is a central "spring" in the shape of a preloaded accumulator, while the individual "springs" are in reality pneumatic cylinders. This way there's no individual compression in said cylinders, which would quickly overheat due to hysteresis at 150 Hz, the pressure is virtually constant due to the common source?

Del West, but I doubt you will learn anything from them. Now if you want to spring the money for a specific application design it might be different.

Brian

hardingfv32 wrote:Del West, but I doubt you will learn anything from them. Now if you want to spring the money for a specific application design it might be different.

Brian

This is bascially what I was trying to say. Specialist engineering companies will build you a bespoke system for big money, but there are no systems available to slap onto whatever engine you want.

that holds true for a " conservtive technology "vlave spring as well.You will have to rely on the spring makers expertise big time...They who ever saw high speed video capture of Valvetrains at high revs tend to get very modest when it comes to taking things for granted in an engine....

Pierce89 wrote:

hardingfv32 wrote:Del West, but I doubt you will learn anything from them. Now if you want to spring the money for a specific application design it might be different.

Brian

This is bascially what I was trying to say. Specialist engineering companies will build you a bespoke system for big money, but there are no systems available to slap onto whatever engine you want.

ahh so that's why I was having so much trouble! Ya ideally, I was hoping for a made system that I could just swap in. But, thank both very much! I will look into your referrals.

meproject wrote:ahh so that's why I was having so much trouble! Ya ideally, I was hoping for a made system that I could just swap in. But, thank both very much! I will look into your referrals.

What kind of prospective mechanical engineer are you? A real mechanical engineer would rather design and build their own system. Mostly because real mechanical engineers typically have such a high opinion of their own talents that they naturally assume they can do a better job of design than the next guy.

You will have make up a set of molds and cast them (the seals) from 'viton' plastic, a good rigid lathe is need to machine titanium for the moving parts in the valvetrain, small chinese lathe will struggle.

On this picture of a Cosworth F1 engine you can see part of the PVRS cylinders at the top:
http://gurneyflap.com/Resources/P7110091.jpg

Cosworth appears to use PVRS cylinders which are separate from the cylinder head with the seals in the piston. It's difficult to tell from the picture but the seals look similar to regular pneumatic cylinder seals. From the pictures in the Ferrari 2000 book Ferrari seem to use a design with cylinders integrated into the head, with stationary seals in the heads instead.

The PVRS system consist of individual pneumatic cylinders for each valve. They are each equipped with two regulation valves and one way valves, one which fills the cylinder with gas if the pressure falls too low (from a pressurized nitrogen bottle) and one which release gas from the cylinders if the pressure gets too high.

I suspect the difficult part with a PVRS system is the seals, they can't be allowed to leak too much - nor can they be allowed to cause too much friction. For F1 a small bottle is used to supply nitrogen at high pressure, but if the system is to be used in other applications I think a small pump will be required.