variable cam profile/timing (was: Twin injector system?)

[Chris Howard]

Hi Adrian,

The main reason they run pneumatic valve springs is the higher natural
frequency of the pneumatic spring compared to a coil spring. This allows
astronomical revs without valve bounce.

regards,

Chris Howard
ch at student.unsw.edu.au

-----Original Message-----
From: owner-diy_efi at efi332.eng.ohio-state.edu
[mailto:owner-diy_efi at efi332.eng.ohio-state.edu]On Behalf Of Adrian Teo
Sent: Tuesday, 30 June 1998 9:33
To: diy_efi at efi332.eng.ohio-state.edu;
diy_efi at coulomb.eng.ohio-state.edu
Subject: Re: variable cam profile/timing (was: Twin injector system?)


At 18:27 6/29/98 -0400, Frederic Breitwieser wrote:
>Adrian, this is something I've always thought would be a good idea...
>coil-operated valves.  Or pneumatic, as someone pointed out on some of the
>IRL cars (am I lost again?).  This gives a decent, wide powerband.  But,
>its not affordable to little folk like me.

Well, the electric/electronic valve technology has nothing to do with
pneumatic valve technology.

The pneumatic valve technology is currently being use on a lot of Formula 1
engines. The nature of this technology is not using air to replace the
camshaft but instead pneumatic (yes, air) springs are utilized instead of
conventional coil springs. The advanteges of such setups is less hysterisis
loss, practically no component fatigue and a significant weight reduction
in the valvtrain components, resulting in an engine that can rev to
unearthly RPM's (typical operatiing range is 12k-18k RPM).

Well, affordable or not, the technology will eventually make it's way down
to conventional vehicles...

-AT
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Adrian Teo
System Administrator, Instruction Support, ASU
Arizona State University, Computer Science & Engineering
http://www.singnet.com.sg/~adriant      adrian.teo at asu.edu
http://falcon.asu.edu/hybrid            falconer at falcon.asu.edu
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