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SPLIT ENGINE 1. Abstract. 2. Introduction. 3. Scuderi split cycle engine. 4. How it works? 5. How does the air get from one cylinder to the other? 6. When and where is the fuel injected? 7. P-V curves. Abstract : The first four-stroke piston was developed in 1876. This four-stroke piston arrangement is still the primary design of engines built today. Todays engines operate at only 33% efficiency.this means that only 1/3 of the energy in each gallon of fuel is used-the rest is lost through friction and heat. With over a billion engines currently in worldwide,even small gains in efficiency will have impacts on the economy,dependency on foreign oil,and the environment. Introduction : Split engines appeared as early as 1914. Split cycle engines separate the four strokes of intake, compression power, and exhaust into two separate but paired cylinders. The first cylinder is used for the intake and compression. The compressed air is transferred through a connecting passage or tube from the compression cylinder into the second cylinder where combustion and exhaust occur. Many different split cycle configuration have since been developed ;however, none have matched the efficiency or performance of conventional engines. Problems with previous split cycle engines : Poor breathing or volumetric efficiency. Low thermal efficiency. Scuderi split cycle engine 1. This engine is proposed by late Carmelo scuderi (1925 -2002) who spent over 40 years inventing, developing and commercializing new technology. 2. The Scuderi split cycle engine technology changes the heart of the I.C engine. 3. By using fluid and thermodynamic techniques, the scuderi technology improves how an engine converts chemical energy to mechanical energy. In a conventional otto cycle engine, each cylinder performs four strokes per cycle: intake, compression, power, and exhaust. This means that two revolutions of the crankshaft are required for each power stroke. The Scuderi Engine divides these four strokes between two paired cylinders: one for intake/compression and another for power/exhaust. How it works : The base Scuderi Engine is a split-cycle design that divides the four strokes of a conventional combustion cycle over two paired cylinders. one intake/compression cylinder and one power/exhaust cylinder. By firing after top-dead center, it produces highly efficient, cleaner combustion with one cylinder and compressed air in the other. Besides the improvements in efficiency and emissions, studies show that the Scuderi Engine is capable of producing more torque than conventional gasoline and diesel engines. How does the air get from one cylinder to the other : There is a short passageway connecting the cylinders. A conventional cam-actuated valve admits air to the combustion chamber, but a pressure activated disk type valve admits air into the passageway from the compression chamber and prevents it from leaking back onto the intake cylinder. When and where is the fuel injected: Fuel is injected directly into the cylinder just as the valve opens. The highly compressed air whooshes in so quickly and atomizes the injected fuel so thoroughly that the spark is fired to ignite it 11 to 15 degrees after TDC, even when running lean mixtures for increased efficiency. P-V curves : In an internal combustion engine, the two high-pressure strokes of compression and power consume and produce energy. The compression stroke is negative work, or energy that the engine expends to do work on the gas. The power stroke is positive work, or energy that the expanding gases of combustion perform on the engine to create mechanical work. The net energy produced by the engine (its efficiency) is the energy generated during the power stroke less the amount of energy consumed by the compression stroke. Second phase: Why it is so exceptional? Solving the thermal efficiency problem by firing ATDC. High pressure and massive turbulence Advantages of Scuderi split cycle design. Disadvantages . Conclusion . Why it is so exceptional? The scuderi split-cycle engine solves both the breathing and thermal efficiency problems. Solving the thermal efficiency problem by firing after top dead center (ATDC). o Although considered bad practice in conventional engine design , firing ATDC in a split cycle arrangement eliminates the losses created by recompressing the gas. o The big issue was not how to solve the thermal efficiency problems of the split cycle engine, but rather how to fire ATDC. High pressure and massive turbulence In the Scuderi Engine, firing after top dead center is accomplished by using a combination of high pressure air in the transfer passage and high turbulence in the power cylinder. This high pressure air entering the power cylinder creates massive turbulence. The turbulence is further enhanced by keeping the valves open as long as possible during combustion . The result is very rapid atomization of the fuel/air mixture creating a fast flame speed or combustion rate faster than any previously obtained Advantages of scuderi split cycle engine. One of the biggest advantages of the Scuderi Split-Cycle Technology is design flexibility. Many features that require additional equipment or are just too difficult to implement in a conventional engine design are easily accomplished with a Scuderi Split- Cycle configuration. For example, supercharging can be added simply by increasing the diameter of the compression cylinder. Piston friction can be reduced by offsetting the compression and power cylinders. A Miller cycle can be achieved simply by increasing the length of the power cylinder. Disadvantages : Cool air never enters the power cylinder so heat would quickly build up causing lubrication oils to break down and components to fail. Water cooled cylinder walls would be required to resolve this. The crossover valve would experience high accelerations so valve train durability could be an issue. This very well might limit the rpm of the engine. Auto-ignition and /or flame propagation could occur in the crossover passage. Conclusion: The scuderi split cycle engine is having thermal efficiency about 42.6%,which is far more better then conventional engine. It greatly reduces the wastage of fuel, which is most important thing to countries like India ,which is dependent on foreign countries for petroleum fuels. It reduces the burden on the imports customs. By using ATDC technique we can greatly reduce the losses created by re-compressing the gas. So , by using this scuderi split cycle engine, we can change the world of IC engines.
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