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Pneumatic Valve Technology

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Was thinking today; surely a pneumatic valves system on an F1 engine removes the need for a mechanically driven camshaft, therefore liberating more power. I know that this is not the only reason it is used; valve springs are notoriously unreliable when having to accept the demands of 18,000rpm.

What are the drawbacks to this technology being used in road car engines? Would a compressor really present too large a packaging issue? Wouldn't the savings in fuel economy off-set this?

Please tell me what I'm missing. Does anyone understand? Hello?

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The current engines still use cams. The pneumatic part of the system just returns the valve to the closed position. Renault did have plans for an electro hydraulic set up without cams, using the onboard hydraulic system but couldn't make it reliable. It does give infinitely variable valve timing though, which is quite exciting. If you could guarantee reliability then I suppose it would be applicable to road cars, but I think for now a spring is more trustworthy than a pressurised system.

valvesystem1.jpg

Pneumatic system

renault_electro-hydraulic_valve_1.jpg

Electro hydraulic system

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Splendid info, thanks Russ.

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Gentlemen,

Please remember that this is a Formula One forum so stop spamming us with your penis enlargement systems and such.

If you do not have anything useful to contribute then you may join any other forum.

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In a nut shell, pneumatics is too bulky, due to the pressure of the system having to be reasonably low (say 110psi or so), but needing to do the same work as a spring able to produce much higher pressure, or a hydraulic system that can easily handle 3000psi. For a 110psi system do the same work as a 3000psi hydraulic system, then the surface area that the pneumatic system must work on has to be three times as large (3x 110psi = 3300psi), hence things get bigger.

Plus pneumatic systems are notoriously bad for sealing. Hydraulics can leak, yet still work as most systems are designed to work at only 90%, or even as low as 80% of maximum...a small leak might only drop oil pressures by 5%. Pneumatics seems, in my experience with them on trucks, trailers, and rail infrastructure equipment I design and work on day in day out, not to have the same work arounds in this regard - think a pin prick in a balloon and trying to keep it inflated.

The best pneumatic system ever used by man thus far would be a triple expansion steam engine. The system is still pneumatic in nature (using steam gas)...but to get the horsepower, those engines were massive in size.

Pneumatics have their place for quick actuation of levers and what not, but in all instances the size needed for pneumatics is greater than that for hydraulics, hence no good for race cars, and probably not viable on a road car.

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Gentlemen,

Please remember that this is a Formula One forum so stop spamming us with your penis enlargement systems and such.

If you do not have anything useful to contribute then you may join any other forum.

You're not interested in abigger penis then? Could off-set the hair loss thing quite nicely....

In a nut shell, pneumatics is too bulky, due to the pressure of the system having to be reasonably low (say 110psi or so), but needing to do the same work as a spring able to produce much higher pressure, or a hydraulic system that can easily handle 3000psi. For a 110psi system do the same work as a 3000psi hydraulic system, then the surface area that the pneumatic system must work on has to be three times as large (3x 110psi = 3300psi), hence things get bigger.

Plus pneumatic systems are notoriously bad for sealing. Hydraulics can leak, yet still work as most systems are designed to work at only 90%, or even as low as 80% of maximum...a small leak might only drop oil pressures by 5%. Pneumatics seems, in my experience with them on trucks, trailers, and rail infrastructure equipment I design and work on day in day out, not to have the same work arounds in this regard - think a pin prick in a balloon and trying to keep it inflated.

The best pneumatic system ever used by man thus far would be a triple expansion steam engine. The system is still pneumatic in nature (using steam gas)...but to get the horsepower, those engines were massive in size.

Pneumatics have their place for quick actuation of levers and what not, but in all instances the size needed for pneumatics is greater than that for hydraulics, hence no good for race cars, and probably not viable on a road car.

More splendid info. Thanks, sheep fiddler Craig.

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does this penis enlargement systems really works? where do you put the stuff ? can you show it on a cucumber

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Pneumatic valve springs gave Renault an advantage with its turbocharged engines, often said to be the most powerful. However, reliability and poor handling of their chassis kept the cars from success until 1989 when Renault provided Williams with its V10 engine to begin a winning streak.

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Well Fiat is using electro-hydraulic variable valve actuation technology on the intake side in their Multiair engines.

And Koenigsegg is one of the few high performance (atm) car manufacturer working on Pneumatic Valve tech for their future cars. Many forum cowboys are already saying it will be impossible for them with the resources they have, but they have proved their critics wrong in the past.

http://performancedrive.com.au/koenigsegg-developing-camless-engine-with-pneumatic-valvetrain-report/

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Simple reason would be cost and reliability.

Cost : If the engines are not designed to rev >11k rpm, A pneumatic system would not really add much performance gain compared to boring old springs. To extract the advantage of a pneumatic systems the engine should be designed to rev higher, which would entail a stiffer block, exotic reciprocating parts, extensive water and oil cooling and significant concessions where emissions are concerned (burning 3 kg of RON 100 per 4-5 km). In short, from a cost standpoint I doubt a consumer would be prepared to shell out much for such an expensive system that requires careful monitoring during its operation. It would be much easier and more practical to just turbocharge the engine (improving efficiency by charging and cooling the air) and getting similar torque figures at lower rpms.

Reliability: I doubt people would want to subject their cars to a shorter servicing cycle due to the extreme pressures put upon the components of the engine. If anything, the public today would rather prefer longer periods in between services. We compare a pneumatic system that contains a pressure vessel, lines, compressor, sensors, electronic control unit, actuators to the alternative - springs. Less things to go wrong there.

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