Diesel Engines Has Travelled A Long Way Since Its Invention In 1893
The first diesel engine was developed in the year in 1893 by Rudolf Diesel and it was named after him. It is simply an internal combustion engine. It became hugely popular with its invention as it is very different and in sharp contrast with petrol or gas engine. These are generally manufactured in two strokes and four strokes version. In the earlier ages of its invention, it was widely used as replacement for the stationery steam engines. Since 1910, these engines were only used in submarines and ships.
From 1930 onwards the use of this type engine widened and it found its use in locomotive, large trucks and electric generating plants. Later on it has also been used in automobiles. From 1970, its use increased to a great extent in larger on and off-road vehicles. In this type only air is initially introduced into the combustion chamber. Then the air is compressed with a compression ratio between 15:1 and 22:1. At about the top of the compression stroke then fuel is injected directly into the chamber using diesel pump and injectors . The heat of the compressed air vaporizes fuel from the droplets. In early systems, the injected fuel with the assistance of compressed air atomized the fuel forcing into the engine through a nozzle. This process was called an air-blast injection. Today the diesel engine service it is raised to extreme pressures by mechanical pumps. It is delivered to the combustion chamber by pressure-activated injectors with the compressed air. With this direct injection method, the injectors spray fuel through 4 to 12 small orifices in the nozzle.
However, the early air injection diesels had a superior combustion. Due to the low combustion rate of the new engines, research is now being performed and patents are taken out for using some form of air injection. This is mainly for reducing the nitrogen oxides and pollution, reverting to original implementation with its superior combustion. The early engines were operated quietly also. In major aspects the modern ones holds the original design of Rudolf Diesel that is of igniting fuel by compression at an extremely high pressure within the cylinder. However, the present day systems use the so-called solid injection process with much high pressure and high technology injectors. The indirect engines that are used widely could also be considered the latest development of low speed hot bulb ignition engines. The diesel fuel injection repairs systems have been popularized due to the complex process of operation.
A vital component of all engines is the mechanical or electronic governor for regulating the idling speed and maximum speed of the engine. It controls the rate of fuel delivery. To start injection results in higher in-cylinder pressure and temperature. Though higher efficiency is achieved here but it also results in elevated engine noise. Moreover, an increased amount of oxides of nitrogen (NOx) emissions also occurs due to higher combustion temperatures. If the start of the injection is delayed, incomplete combustion takes place and the fuel efficiency also gets reduced. Along with it an increased amount of exhaust smoke containing unburned hydrocarbons also emits.