Why have NITTO MFG. WORKS been manufacturing WANKEL ROTARY ENGINE?
The engines, mounted on the cars moving
around the world at present, are mainly, almost@ all, run by "Reciprocation System (4-cycle, 2-cycle and diesel) Engine"
with the mechanism of revolving the output shaft, converting the reciprocating
motion of the piston to the rotary action by the crank mechanism.While
on the other hand, "rotary engine" collectively means that the
engine,@ with the rotorequivalent to the piston, makes the rotary action from the
very beginning, and can directly convey the rotary action to the output
shaft."Rotary engine" with various kinds of mechanism has been
designed so far, but the rotaryengine,@ which mechanism has been invented by German Dr. Wankel is called as "WANKEL
ROTARYENGINE" (hereinafter referred to "ROTARY ENGINE").
"ROTARY ENGINE" do not make the reciprocating motion, any unbalance
is never created and therefore "ROTARY ENGINE" have the advantage
to give extremely smooth movement.Let us compare "ROTARY ENGINE"
with "Reciprocation System (4-cycle and 2-cyle) Engine.
1) 2-cycle engine : The mechanism is simple as one rotary action of output
shaft per burst, which generates high-power. That's why the engines were
employed for many applications before.But, the actions of air intake and
exhaust process cannot be fully exercised due tothe output shaft is forced
to turn right round 360 degrees.Because of that, it causes about 20-30%
inferior in the generating power and the fuel efficiency than "ROTARY
2) 4-cycle engine : Using the valves for air intake and exhausting, the
output shaftturns 2 times (720 degrees),spending long time. 4 process actions
of "air-intake, compression, burst with expansion and exhausting"
areseparately exercised, comparing with 2-cycle engine, therefore the structures
arecomplicated by the mechanisms of making intake valve and exhausting
valve move.Because of those valves, they cause trouble on high speed rotation,
the output poweris poor than 2-cycle engine due to one burst per 2 times
rotation.On the other hand, "ROTARY ENGINE" burst once per the
output shaft one time rotation, sameas 2-cycle engine. And also, 4 process
actions of "air-intake, compression, burst withexpansion and exhausting"
are exercised without the need for the valves to intake andexhaust, similar
to 4-cycle engine.From the above 2 points, that is why "ROTARY ENGINE"
do, in a theoretical sense, generate 2 times of power than 4-cycle engine
by the same output shaft rotation.Although NITTO MFG.WORKS have explained
that in the case of "ROTARY ENGINE", one rotary action of output
shaft per burst is exercised same as 2-cycle engine, the main or biggest
difference is there in the numbers of rotation of the output shaft per
cycle on the execution of the 4 process actions of "air-intake, compression,
burst with expansion and exhausting", comparing with the reciprocation
system.As explained earlier, "ROTARY ENGINE" do exercise 4 process
actions taking even three rotations 1,080 degrees. It is 1.5 times longer
than 4-cycle engine, while 2-cycle engine makes one rotary action 360 degrees
per burst, 4-cycle engine does one series of action in two rotations 720
degrees.NITTO MFG. WORKS do hope our customers can share the advantages
of "ROTARY ENGINE", whichbring together the respective merit
of 2-cycle engine and 4-cycle engine, judging fromthe above.The reciprocation
system create vibration by any means because the piston are always making
the back-and-forth motion. On the other hand, "ROTARY ENGINE"
can, in theory,make vibration null or zero, as all the internal actions
are rotary motions. NITTO MFG. WORKS do hope our customers can understand
that the "ROTARY ENGINE" have the incomparable features like
apples and oranges, against the reciprocation system and how "ROTARY
ENGINE" do always good jobs.On 1961. Japanese MAZDA (formerly TOYO
KOGYO) started to work toward practical use ofthe dream "ROTARY ENGINE"
and succeeded for the first time in the world, and then on 1967,"COSMO
SPORT" was launched to the market by mounting the production model
"ROTARY ENGINE".In the model industry, Japanese OGAWA SEIKI COMPANY,
requested by German GRAUPNER COMPANY,succeeded on 1970 to develop just
after the launching of "COSMO SPORT" by MAZDA , and started their
marketing of the production model "ROTARY ENGINE" with 5 c.c.
GLOW Fuelspecification. This achievement was the very big news in the model
industry.NITTO MFG. WORKS think we had better tell about how Dr. Wankel
worked out for thedevelopment of "ROTARY ENGINE".Dr. Wankel had
spent the most many hours for the basic study on the air tight (sealing)of
the combustion chamber, since he started to develop. The data reported
that Dr. Wankelhad continued his study about this basic subject for 10
years long.As a result, Dr. Wankel had come up with the sealing formation,
consisting with APEX Seal (partition type), Side Seal and Corner Seal,
this is the characteristic for "ROTARY ENGINE".The "ROTARY
ENGINE" designed and manufactured by MAZDA have been embodying full-fledged
application of Dr. Wankel's theory and characteristic sealing formation
as faithful as possible from the very beginning of their development.However,
when reviewing the small size "ROTARY ENGINE" including OGAWA
SEIKI COMPANY made,NITTO MFG. WORKS have never been able to find out any
of the full-fledged and real use of production model "ROTARY ENGINE" employing all the sealing formation, consisting
with APEX Seal (partition type), Side Seal and Corner Seal, which were
coming up after theconvulsive effort and study for long time by Dr. Wankel.