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 ENGINE".
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.