Internal Combustion Engines

1475 WordsOct 24, 19996 Pages
Internal Combustion Engines An internal-combustion engine is a heat engine that burns fuel and air inside a combustion chamber located within the engine proper. Simply stated, a heat engine is an engine that converts heat energy to mechanical energy. The internal- combustion engine should be distinguished from the external- combustion engine, for example, the steam engine and the Stirling engine, which burns fuel outside the prime mover, that is, the device that actually produces mechanical motion. Both basic types produce hot, expanding gases, which may then be employed to move pistons, turn turbine rotors, or cause locomotion through the reaction principle as they escape through the nozzle. Most people are familiar with the…show more content…
Most ignition systems require an external electrical energy source in the form of a battery or a magneto. Spark-ignition engines require a means for mixing fuel and air. This may be either a carburetor or fuel injection. A carburetor atomizes the fuel into the engine's incoming air supply. The mixture is then vaporized in the intake manifold on its way to the combustion chamber. fuel injection sprays a controlled mist of fuel into the airstream, either in the intake manifold or just before the intake valve or valves of each cylinder. Both carburetors and fuel injectors maintain the correct fuel- to-air ratio, about one part fuel to fifteen parts air, over a wide range of air temperatures, engine speeds, and loads. Fuel injection can compensate for changes in altitude as well. Internal-combustion engines require some type of starting system. Small engines are generally started by pulling a starting rope or kicking a lever. Larger engines may use compressed air or an electric starting system. The latter includes a starter--a high-torque electric motor--to turn the crankshaft until the engine starts. Starting motors are extremely powerful for their size and are designed to utilize high currents (200 to 300 amperes). The large starting currents can cause a battery to drain rapidly; for this reason a heavy- duty battery is usually used. Interrupting this connection is an electrical switch called a solenoid, which
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