I'm afraid I'm not able even to soften a bolt, but I'm somehow
imaginative, close to fantasious.  Very early research published in
SAE papers and other places, has shown that a peripheral port with
an square shape, corners more or less rounded, is better than the
usual circular intake port in peripheral intake ported engines, the
Norton motorcycle engines had a rectangular peripheral intake port,
 or perhaps closer to oval; if the intersection between intake duct
or manifold and stator or epitrochoid surface is streamlined,
 results are also improved, the more efficient shape for this is a
parabole, an square angle gives an efficiency of around 75%, if you just
add a slope, it can improve to 80% or more, and the parabole would give
nearly 99% efficiency, there are always losses because of drag and things
like.  An intersection in right angle does produce turbulent flow, with
losses in volumetric efficiency.  The improved results with a
rectangular or square shaped peripheral port seems having been more
noticeable in high speed, no big rpm fluctuations engines, that is
the kind of use an aircraft engine would have.

Theoretically, tilting the angle of the main intake duct line in a different
angle than perpendicular or parallel to the rotor long part of its
surface, considered for this also as a rectangle, may allow
generating inside the combustion chamber any desired degree of
turbulence or swirl, that can be adjusted to improve combustion.
 Harry Ricardo attributed to this swirl some of the advantages of
his line of single sleeve-valve engines, that were among the top in
power, reliability and fuel economy of all reciprocating aircraft
engines of WWII.

However, it seems that turbulence inside the combustion chamber is a
double edged sword, too much may be close to detonation, may be, and
the determination of the right degree of turbulence within the combustion
process for every possible combination of rpm, throttle opening and other
settings in an engine intended for aircraft use may be expensive
both in terms of money and in time, and probably there are so many variables
involved, that evaluating all posible combinations is only at the
reach of big companies.

I beg your pardon, these comments are at a high school level, or
even for younger people, not for men seriously involved an
experienced in the field of aircraft RCEs, but it's the level of my
comments in aaroncake.net and in some articles in Wikipedia, so if
you have the time and the envy for this, I'll appreciate any
feedback on these concepts.

Have a nice weekend, best regards, salut +

Jose Gros-Aymerich
Madrid, Spain

Jose,

Search;

Mazda Skyactiv.

Somender Singh.  Groove technology on recip engines.

Dale Davies


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