On Apr 16, 7:15*am, Ed Huntress wrote:
On Tue, 16 Apr 2013 12:28:39 +0100, David Billington
wrote:
On 16/04/13 01:58, Ed Huntress wrote:
On Mon, 15 Apr 2013 17:36:34 -0700 (PDT), BottleBob
wrote:
All:
* * * * Thought I'd mention these for those automotive techies that may not have heard of them.
* *Adios pushrods, camshafts, valve springs, rocker arms, poppet valves, etc. etc. *Run more compression for more efficiency, higher RPM, cooler running engine, less maintenance. * Too good to be true you say?? *Check this vid out.
http://www.youtube.com/watch?v=pDsRa4eT7co
http://www.coatesengine.com/csrv-advantages.html
http://www.coatesengine.com/csrv-system.html
* *Ed's going to miss hot lashing the valves on a Saturday afternoon. * JK *LOL
Very nice! Axial-shaft rotary valves. They've been around for at least
60 or 70 years. g I think they were tried in aircraft engines even
earlier than that.
They always fail, mostly due to sealing problems. When I have more
time I'll see what I can find on the old attempts.
New materials may make them practical, but I wouldn't put my money on
it. If Mazda couldn't make their rotary-valve, pre-Wankel Cosmo last
in service, back in the '60s, I'm skeptical about this one.
But there's always hope....
Some rotary valve engines are over 100 years old now see
http://www.douglas-self.com/MUSEUM/P...otaryValveIC/R...
Oh, that's interesting. That looks like the complete history of the
type.
It's funny that I haven't seen a reference to the Mazda engine for
over 40 years. It was a disk-type -- actually, the valves were
hemispheric -- and the valves were made of ceramic. It was quite
advanced, I thought, but it must have died without leaving any
progeny.
--
Ed Huntress- Hide quoted text -
- Show quoted text -
The school library had a book on I.C. engines with unusual valve gear,
covered all sorts of rotary and sleeve valves. Some made it into
production like the Crossley gas engines and Knight sleeve-valve
engines, others were a bust. Most had lubrication problems, either
they sucked oil like demons or bound up due to problems with
distributing same. Sleeve valves hung in there the longest, Brits
used them in a whole series of aircraft engines, I have no idea of
MTBO on them, though. The attraction there was that designers weren't
stuck with a round hole for entrance and exit and valve timing could
be changed with the shape of the holes in sleeve and cylinder. No
obstruction for gas passage from a poppet valve head, either. But
they also had lube problems along with heat flow problems when they
started superchargning them. Lube problems persist with any rotary
valve engines I've seen in the last 40 years. Big announcement
followed by a quiet liquidation of the development company a little
later. Good for prying Ferrari funds out of a V.C. outfit, though.
Stan