Working of the Wankel Engine - Term Paper Example

Running Header: Wankel Engine Student’s Name: Instructor’s Name: Course Code: Date of Submission: Table of Contents Table of Contents 2 Introduction 3 Working of the Wankel Engine 3 History of Wankel Engine 5 Evolvement of the Wankel engine 6 The future of the Walken Engine 7 Conclusion 9 Works Cited 10 Introduction Wankel engine is an internal combustion type of engine that utilizes a rotary design towards the conversion of a rotating motion other than use of reciprocating pistons. It usually has four stroke cycle that occurs within a space between the epitrochoid shaped housing that is oval in shape. The rotor is in a similar shape to a Reuleaux triangle although the sides are somehow flat (Erik 143). The design is made in such a way that it gives out a smooth high-rpm power from the packed together size. The engine is also referred to as rotary engine. A German engineer known as Felix Wankel invented the engine that came to be named after him. In 1929, Felix received the first patent of the engine. He started its development in the early 1950s at NSU Motorenwerke AG (NSU) (Berger 56). In 1957, Felix completed a working prototype. The concept was licensed by NSU to companies within the globe; these have continued to improve the engine’s design. The engine has developed with time after various companies were given licences that has lead to its development. Wankel engine has a compact design that enables it to be installed in various vehicles and other devices including chain saws, go-karts, auxiliary, automobiles including racing cars, aircrafts among others. This report will analyse the way engine was 20 years ago. It will also analyse how it has developed during the 20years and how it might be in future. Working of the Wankel Engine Wankel engine usually has four strokes of a typical Otto cycle. This takes place between a symmetric rotor that is three sided within an inside of a housing. In a basic single-rotor Wankel engine, a rotor is surrounded by the oval-like epitrochoid-shaped housing. It is usually triangular and has bow-shaped flanks (Erik 150). It has a three pointed curve that has a constant width and usually bulged in the centre part. At the apex of each face is a metal blade that forms a seal to the outside of the combustion chamber. There are also metal rings on each side of the rotor that seal to the sides of the combustion chamber. In a theoretical perspective, the shape of the rotor between the three fixed apexes is for reducing geometric combustion chamber volume as well as maximizing the ratio of compression. Therefore, the symmetric curve that connects two rotor apexes is increased in the inner housing’s shape direction whereby constraint does not touch the housing at any rotation angle (Erik 152). The eccentric shaft or E-shaft or central drive shaft pass through the rotor’s center whereby it is supported using fixed bearings. The rotors usually ride on eccentrics that are essential with the eccentric shafts. Rotors usually rotate around the eccentrics whereby they make revolutions that are orbital within the eccentric shaft. The corner seals the rotor against the housing peripheral dividing it into 3 rotating combustion chambers (Ian 67). A pair of synchronizing gears controls the rotation of every rotor within its own axis. In every side of rotor housing, there is a mounted fixed gear. This engages a ring gear that is attached to the rotor which makes sure that the rotor goes for a one third turn of every turn of the eccentric shaft. Diagram 1 wankel cycle (A-rotor B-Eccentric shaft) History of Wankel Engine Wankel started a Technical Institute of Engineering Study (TES) after the war. It is at this institute that he continued with research and development of the rotary engine as well as rotary compressor for commercial uses. NSU, a motorcycle manufacturer had interest in the research work of Wankel. NSU and Wankel formed a partnership in the development of the engine. Initially, NSU and Wankel focused on developing an engine that had a trochoid housing. However, NSU completed its rotary compressor development which it combined with Wankel-type supercharger. A prototype of DKM rotary engine was completed by Wankel and NSU in 1957 (Berger 56). This had combined a cocoon-shaped rotor housing that had a triangular rotor. However, the structure was somehow complicated due to rotation of the trochoid rotor housing rotation hence making it impossible to use the engine. The redesign of the engine was done and completed in 1958 despite having a complicated cooling system comprising of water-cooled housing having an oil-cooled rotor. This engine became to be the predecessor of the current Wankel rotary engine. Evolvement of the Wankel engine NSU started the production of Wankel engine luxury car referred to as R0 80 in 1967. Nevertheless, it had some problems with apex seal wear. This resulted to various engine failures leading to large warranty costs for NSU. This interfered greatly the development of Wankel engine. In eliminating the problems of apex seal wear, cross-hollow seal was developed through drilling small holes within the metallic apex seal. Mazda said to have solved the problems due to apex seal; it was capable of running test engines at a very high speed of 300hours without experiencing any failure. Nevertheless, the technique was not used in the mass-production of rotary engines (Lance and Ian 90). Initially during the development of rotary engine, it had some oil leaking problems. Engine oil leaked into the combustion chamber that led to excessive consumption of oil. The problem of the oil leak was identified to be oil seal that lead to development of an innovative Mazda-Unique oil seal. Mazda further developed the engine for years whereby its first car was Cosmo 110S of 1967. Several other cars with Wankel engines or rotary engines were made by Mazda which were said to be smooth in terms of its operations. Mazda considered developing the engine in such a way that it could satisfy hydrocarbon emission standards. In 1974 and 1976, ferric alloy apex seals as well as NSU rotor were used on Suzuki motorcycle. This is in an effort to increase its operating time or life (Lance and Ian 94). After oil crises period that faced the world around 1970s, various manufacturers of the automotive started developing cars that were fuel efficient. This made Mazda drastically reduce the fuel consumption of the rotary engine. This is after initiating the Phoenix project that had a target of 20 percent rise of fuel economy. After several challenging development in terms of engineering development, various parts of engine including thermal reactor systems as well as carburettors were improved (Hege 110). Furthermore, other developments including enhanced efficiencies in terms of reaction were also put in place. This was through the incorporation of a heat exchanger within the exhaust system; this led to 40percent rise (Berger 56). A first catalytic converter system was developed successfully for the rotary engine. Other engine developments that came after included reaction-type exhaust manifold, the high-energy ignition system, the split secondary control of air as well as two-stage pellet catalyst system that were successively developed. In 1980, a Russian company was creating special engines that were designated as VAZ-311 whereby it started producing Wankel-powered VAZ-2106s or VAZ-411 engine that had 2 rotors. The engine were further developed to engines that had electronic injection for helicopters and aircraft (Hege 112). In 2003, mazda relocated the exhaust as well as intake ports from the rotary housing periphery to the sides. This allowed even for large overall ports. It also led to better and improved airflow as well as more gains in terms of power. In an effort to solve some of the problems on the Wankel engine due to seals, the engine was designed in such a way that it used a keystone scrapper side seal. This has a better economy in terms of fuel; it is friendly to environment as well as being reliable (Lance and Ian 90). The future of the Walken Engine There are likely to be more improvements of the engine in an effort to deal with the rising oil challenges globally. This is as oil prices continues to rise sharply hence the need for fuel efficient engines. The need for more less polluting cars is also increasing the need and importance of cars that are less pollutant in the atmosphere. Therefore, the engine is likely to be developed in such a way that it can release less amounts of carbon. The seals are likely to be replaced with ones that are more efficient. The efficiency of the engine is greatly reduced by its less effective seal. This is due to sandwiching of aluminium pieces and cast iron. In case they are exposed to cooling and heating cycles, this results to high loss of seals between the housing and rotor. This is likely to lead to more development of the engine especially in that section which has been a great problem even from the past. The redesign and redevelopment of this section is likely to have a great impact in the future of the engine. Therefore, the future developments are likely to occur within the seals confining its success mainly to applications like sports and racing vehicles. In future, the engine may be designed in such a way that pumping losses may be reduced significantly when the fuel injection rates are significantly improved. The engine burns a small quality of fuel due to its design. This is likely to lead to improved designs in future that will provide more room for large amounts of fuel into the combustion area. The design and size of the engine is likely to be improved in future by being made smaller and simple in terms of design leading to saving more in terms of costs of construction. This is likely to greatly increase its usability among the vehicles and aeroplanes. The high volume to surface area ratio that leads to less efficiency of the engine is likely to improve and be redesigned in future in an effort to increase its efficiency and performance. Engineers as well as designers will have to redesign the engine for it to become acceptable and efficient in the ever increasing market of technology. The engine is likely to increase its usability and popularity in future due to some of its significant features including its quick reaction to throttle changes as well as its capability to deliver a surge of power quickly with increase in demand. It is also likely to be used more in aircrafts in future due to its smaller frontal area as compared to piston engines of equivalent powers. This allows more aerodynamic nose to be designed within it. Conclusion In 1970s, several companies developed the Wankel engine including Mazda, Peugeot, Daimler Benz, and General Motors. However, Mazda is one of the most extensive automotive manufacturers who have extensively used Wankel engine since its invention. Currently, there are few engines that are using Wankel engine, those include Mazda RX-8, and these are motors that are commonly related to Mazda RX-7 as well as RX-8 (Manfred 72). The Wankel engine development has been advantageous in that they are simple and have fewer moving parts. They do not have valves with its rotors being geared directly to the output shaft hence no need of connecting rods like in case of piston engines. The engine does not have balance weights and crackshaft among others hence making it lighter. This saves the time and cost as well as energy needed in its process of construction. The changes in factors like oil crisis or scarcity as well as need for greener energy production and standards demanding for greener energy have led to evolvement of the engine design with time. However, despite the simplicity of the engine as well as being small in size. It is not greatly used in the current manufacture of vehicles. The problems with rotor seals as well as high surface to volume ratio in the combustion chamber of the engine that led to thermodynamically less efficient engine resulted to high and fierce resistance among many producers of the engine. Works Cited Berger, Michael. The automobile in American history and culture: a reference guide. New Jersey: Greewood Publishing Group, 2001. Erik, Eckermann. World history of the automobile. New York: SAE, 2001. Hege, John. The Wankel Rotary Engine: A history. North Carolina: McFarland & Company, Inc., Publishers, 2001. Ian, McNeil. An encyclopedia of the History of Technology. London: Routledge, 2002. Lance, Day and Ian, McNeil. Biographical Dictionary of the History of Technology. London: Routledge, 2003. Manfred, Weissenbacher. Sources of Power: How Energy forges human history. New York: ABC-CLIO, 2009. Read More