OT: Cool revolutionary head design - no more valves

[jdbubb at ix.netcom.com (Dan Bubb)]

Rotary valves have been around for a long time. I saw this design heralded
in Racecar Engineering mag over 5 years ago as the next best thing to sliced
bread, but here we are with not one racing engine in the world using it!
Indy cars use standard "old" 4 poppet valves/cylinder with coil springs,
conceptually just like what we have in our Sciroccos, especially this year
now that it's a spec engine formula with all engines made by Cosworth.
Formula 1 engines use a pneumatic valvetrain, but all it is (simplified, of
course) is a standard poppet valve that has a pneumatic chamber to close the
valve instead of a spring. It uses nitrogen under ~80 bar pressure.
Pneumatic valve closure has been used in Formula 1 since the early 90's and
was one of the major advances that allow the 19000 RPM used by some F1
engines today. It's still a poppet valve!
Solenoid control of poppet valves has been tried by a number of
manufacturers, but the assessment of the design by Mario Theissen (BMW
motorsports chief) from a reecent Racetech or Racecar Engineering mag is
that it's a lot of weight, it's weight that is high up on the engine
adversly affecting CG, and the power requirement to drive the solenoids is
huge. Unlikely to see it in formula 1 anytime soon. Roadcar use....unclear.

BMW's current hotshit valvetrain that allows infinitely variable lift and
duration is purely a mechanical design.
Quoted from an Autospeed article; "In addition to direct fuel injection, the
V12 also runs the BMW Valvetronic system. Valvetronic uses fully variable
intake valve opening times, controlling both the duration and degree of
valve motion. This is achieved by the use of an interim lever fitted between
the camshaft and the two intake valves on each cylinder. The position of
this interim lever relative to the camshaft can be adjusted infinitely by an
additional eccentric shaft operated by an electric motor. Depending on the
position of the eccentric shaft, the lever converts valve lift into a larger
or smaller movement of the valves."
http://autospeed.com/A_1785/cms/article.html for those of you that have an
Autospeed subscription.
Still uses the good old camshaft and valve springs!
There is some cool technology out there, but, as always, it needs to be good
enough to overcome the existing knowledge and manufacturing base before it
becomes widely used.
As an aside the Coates website has its fair share of marketing technospeak
i.e. Bullshit! Just as one example, poppet valves running at 2500F!  Right
below melting temp and way over the temp of the exhaust gas? Don't think so.
Dan


----- Original Message -----
From: Ryan H <rhock99@epix.net>
To: Mark <maardak@yahoo.ca>
Cc: <scirocco-l@scirocco.org>
Sent: Saturday, June 14, 2003 12:09 AM
Subject: Re: OT: Cool revolutionary head design - no more valves


> Yeah, that's definitely cool stuff.  They've been using it in Indy (?)
cars for a while now, I think they call it "pneumatic" valvetrain.  Works
kinda like a rotary carb.  Probably makes for an astronomical redline.  BMW
also developed a valvetrain which uses solenoids to open and close the
valves, making the valve timing/lift infinitely variable, meaning who needs
to change cams when you don't have them?  Want more lift or duration?  Chip
it.  And no throttle body either!  Look for this technology to filter to
other companies soon too.
> >
> > From: Mark <maardak@yahoo.ca>
> > Date: 2003/06/13 Fri PM 10:53:23 EDT
> > To: scirocco-l@scirocco.org
> > Subject: OT: Cool revolutionary head design - no more valves
> >
> > I gleaned this from the forum about the rear mounted turbo...  Blew me
away...  One of
> > the many things that frequently keeps me up all night has been trying to
figure out a way
> > to eliminate poppet valves of a conventional head, but I guess this guy
beat me to it!
> > ;-)  Damn...  Oh well, my mind never shuts off, so hopefully I'll
eventually think of
> > something original that'll make me millions...  :-)
> >
> > <http://www.coatesengine.com>
> >
> >
> > Mark.
> > 80 S
> > 81 S
> >
> >
> >
> > ______________________________________________________________________
> > Post your free ad now! http://personals.yahoo.ca
> >
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