Electronic valve control

[Gary Derian]

Its always fun to be creative but these
ideas for rotary valves, etc have all
been thought up more than 80 years ago.
The Darwinian evolution of the internal
combustion engine has let to what we
have today.  Spring return poppet valves
are the best mechanical answer.  Rotary,
desmodromic, etc have all been tried and
abandoned.  New technology in
electronics may lead to a better answer
but not yet.  Hybrid powertrains are
reducing the speed and load range an
engine is required to operate in so
variable valve timing is less important
now than before.

IMO, the best engines of the 80 years
ago era used sleeve valves.  They had a
moving steel sleeve between the cylinder
and piston.  The sleeve had ports cut
into it for intake and exhaust like a
two stroke but they ran as 4 strokes.  A
point on the sleeve moved in a circular
manner. The holes in the sleeve would
line up with ports in the cylinder wall
to create the intake, compression,
expansion, exhaust.  The sleeve extended
into the head.  This gave a
hemispherical combustion chamber with a
central spark plug.  Another advantage
was that at no point did the piston stop
relative to the sleeve.  This improved
lubrication and these engines lasted a
very long time.  Even so, the cost and
complexity of driving the sleeves
obsoleted these engines.

Gary Derian <gderian at cybergate.net>

Fred Breitwieser wrote:
> So, the next brainy off the cuff idea
would be to have two holes at the top
> of the chamber, and the cylinder mates
with either hole during the
> intake/exhaust strokes, and in between
the chamber is sealed as the holes
> don't line up.
>
> Would have to radius all the edges to
prevent detonation, and the material
> thickness of the top of the head where
the cylinder rests would have to be
> awfly thin, otherwise as you said, it
would add to the clearance volume.
>