Sunday, October 15, 2017

Diesel Engine

A diesel engine is a type of internal combustion engine that is similar to the gasoline engine, but required no electrical ignition system or carburetor. It was invented by Rudolf Diesel, a German engineer, who obtained a patent for the design in 1892. Diesels employ high compression ratios to elevate the compressed air temperature sufficiently to ignite a low-grade fuel that is injected into the cylinder. Component of diesel are usually heavier than those of gasoline engines because of the additional compression ratio and power output.

Diesel engine employ a system of fuel injection to spray the fuel into the cylinder after the air has been compressed by the piston. This mixture burns; the expanding gasses push the piston down and thus supply power. The timing of this fuel injection is just as critical as is the spark that ignites the fuel in the gasoline engine. Therefore, the injection mechanisms are mechanically linked to the crankshaft. Since each cylinder takes in and compresses a fixed amount of air, the power of the engine is varied by the amount of fuel injection. The timing as well as the duration and pressure of fuel injection, is design so that the maximum useful energy is obtained from the fuel for a particular range of speed, power, acceleration, or other working condition.

Diesel Engines, like other internal combustion engines, require an exhaust system, a cooling system, and a starting system. Because of the unusually high compression ratio, diesel engines need a powerful starting system. Some diesel engine use an electric motor or an auxiliary gasoline engine, whereas others use compressed air or spark ignition to start the engine. Diesel engines have always been popular power plants for large vehicles such as buses, trucks, locomotives, and ships. Small diesels have been used in automobiles, although the noise, soot, and pollutant they produce have discouraged that use in the United States.

Today continuing effort are being made to apply diesel power to additional stationary uses, such as in central generating station, industrial power plants, oil pipelines, and irrigating pumps. The diesel has been successful because of its operating advantages, such as low maintenance costs, greater efficiency, high power output, and fuel economy under all loads.

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