Paul,
Do you know anyone who could act as a consultant to a company
that is developing a new type of rotary engine? They need help
with seals. Mazda seals won't work.
Thanks.
jd
No I don't. If they would consult with me I would
tell them to forget it. Rotary engines have been around
since the 1500's. Felix Wankel studied the heck out of them.
I have his very comprehensive and detailed paper on the subject.
Like Kenichi says; a new rotary has a snow balls chance
in hell of working given the billions Mazda has already invested
in the Wankel. What Mazda has achieved is quite remarkable.
Paul Lamar
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By Kenichi Yamamoto from his book "Rotary Engine" 1981
1.3 REQUIREMENTS FOR A PRACTICAL ROTARY ENGINE
Although various types of rotary engines have been
developed to date, there are few that do not qualify as internal
combustion engines or do not qualify as a practical engine even
if they satisfy the qualifications of an internal combustion
engine.
The requirements for a rotary engine to be qualified
as a practical internal combustion engine can be summed up in
the following five items. The practicality of various ideas on
rotary engines can be judged by evaluating them by these
criteria:
(1) Every moving part, including the timing mechanism, should
make a rotating motion. A mechanism having a reciprocating
inertia will increase mechanical noise and vibration, and will
work against high speed and high revolution. [In addition
mechanisms that reciprocate generate reversing loads. Reversing
loads lead to reversing stresses. Reversing stresses lead to
metal fatigue and limited life. The Wankel rotary engine has no
reversing stresses therefor the life of the major parts such as the
eccentric shaft and rotor are unlimited unlike, crankshafts, connecting
rods, pistons and poppet valves. Paul Lamar] Accordingly, structures
that require intake and exhaust valves and mechanisms using the rotors
oscillatory motion are not desirable.
(2) Gas seals or the working chamber should be three
dimension-ally reliable. The gas seal mechanism of a rotary
engine should be constituted by connecting the individual seals
three dimension-ally. Among the many ideas we come across are
those that don't show such three dimensional thoughts.
(3) Appropriate gas exchange of intake and exhaust should
take place. Together with having a mechanism that can correctly
open and close the ports, sufficient time for intake and exhaust
should be provided especially for high speed and high
revolution. Among the ideas on rotary engines, there are some
that ignore this point.
(4) Every component part should have the strength to endure
high speed and high pressure. As the component parts are
exposed to high pressure, high sliding velocity and high heat
load, every part should have sufficient allowance in size and in
shape.
(5) Sufficient cooling and lubrication should be provided.
In order to qualify as an internal combustion engine, although
this is related to above (4), durability against high heat load,
high sliding velocity, etc. are required. Therefore, the
structure should be simple, and the ideas on rotor cooling,
lubrication of seal parts, and oil seal structure should be
those that are given adequate thought.
Also, it is desirable for a practical rotary engine to
have a simple and compact structure. When we evaluate the
various type's of rotary engines devised to date in view of the
above mentioned requirements, the NSU Wankel type rotary engine
is the engine that best satisfies the above mentioned
requirements.
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History of the invention of the rotary engine by Julian Marsh
1588 Ramelli, an Italian engineer invented a water pump which
continues to be used in oil pumps and compressors.
1636 Pappenheim, a German engineer invented the gear pump which
is still used to lubricate engines. This gear pump made it
possible to dispense with the reciprocating slide valves used by
Ramelli. [Fig 3]
Pappenheim drove his machine by an overshot water wheel set in
motion by a stream and was used to feedwater fountains. The
emperor Ferdinand II granted him a privilege - the equivalent
of a patent in respect of this invention.
Even in the 17th century, engineers were trying to solve the
problem of leak-proofing between moving parts and this problem
continues to be the Achilles heel of the rotary piston engine
although Mazda would seem to have reduced this problem to
manageable proportions.
1650 Otto von Guericke built a vacuum pump which employed
leather washers to prevent leakage between cylinder and piston.
1782 James Watt who invented the steam engine?s connecting rod
crank mechanism which made it possible to convert the piston?s
reciprocating motion into rotary motion designed an oscillating
piston machine in which a wing-shaped rotary blade performed an
almost complete revolution uncovering inlet ports in a chamber
separated off by a curved radial wall. [Fig 4]
1799 One of Watt?s co-workers, Murdock, adapted Pappenheim?s
gear pump to create a rotary piston steam engine. [Fig 5]
1846 Elijah Galloway built the first rotary piston engine with
inner epicycloid and enveloping outer line. [Fig 6]
1859 Jones, modified Pappenheim?s gear pump and produced a
double rotor with only two teeth per gear. Rootes compressors
and pumps employ this principle. [Fig 7]
1900 Alotham and Franchot designed a vane compressor comprising
a bust rotating inside a cycloidal housing. [Fig 8]
1901 The American, Cooley, lodged a patent for a rotary piston
engine with an internal epicycloid and enveloping outer chamber.
[Fig 9]
1908 The Englishman, Umpleby, transformed Cooley?s steam engine
into an internal combustion engine but experienced problems with
gas tightness. [Fig 10]
1923 A Swedish patent was granted to Wallinder and Skoog in
respect of a true rotary piston thermal engine with toothed
meshing, enveloping interior hypocycloid and internal five
pointed rotor with a 5:6 rotation ratio which could be used as
either a two or four stroke internal combustion engine.
[Fig 11]
1938 Sensaud and Lavaud, (the French engineers responsible for
the Traction Avant automatic gearbox which was a failure)
applied for a patent for a rotary piston engine with internally
meshing gears in a hypocycloid housing and a 5:6 reduction
ratio. Both Renault and Citroën, at the instigation of the
French Air Ministry provided backing for this project and a
number of engines were built at Batignolles. Unfortunately the
engine failed to live up to expectations and the project was
abandoned. [Fig 12]
1943 The Swiss manufacturer Bernard Maillard built an air
compressor based on a British patent for a rotary piston machine
with a 2:3 ratio and internal hypocycloid surfaced chambers.
Leakage under pressure made it impossible to use this design as
a thermal engine. [Fig 13]
