“Diesel Engine” is an engine that uses compression ignition method. It is also known be an engine that uses heavy diesel oil. The main point is Diesel Engine does not use spark ignition for combustion. Original cycle of Diesel Engine proposed by Rudolf Diesel in 1892, which was a constant temperature cycle that was based on the Carnot theory. The main idea of Diesel was to tightly compress the air to exceed the temperature of the air of combustion. Diesel describes the compression required for his cycle in his 1892 US patent #542846:
“according to curve 1 2, pure atmospheric air is compressed to such a degree that before ignition or combustion takes place, the pick pressure & the highest temperature of the diagram are obtained that is to say as the temperature at which temperature the subsequent combustion has to take place but not the burning point. Let’s assumed that the subsequent combustion will take place at 700° temperature. The initial pressure must be sixty-four atmospheres in that case and for 800° centigrade temperature the pressure must be ninety atmospheres or that ratio. Thus, compressed into the air is gradually introduced from the exterior and then finely divided fuel that ignites on introduction. From the time air is at a temperature far above the igniting point of fuel. Characteristic features of the cycle are therefore, increase of temperature & pressure up to the maximum level, prior to combustion by mechanical compression of air not by combustionand the subsequent performance of work without increase of temperature &pressure by gradual combustion while a prescribed part of the stroke that is determined by cut-oil.
Diesel realized that his original cycle would not work & soon he adopted the constant pressure cycle in later years. In Diesel’s1895 patent application he describes the cycle. There is no longer a mention of compression temperatures exceeding temperature of combustion was Noticed. The compression must be high enough for ignition is mentioned in all of them.
“1. The combination of a cylinder & piston arranged to compress air to a degree producing temperature above igniting point of fuel in an internal combustion engine. A supply for compressed air, a distributing-valve for fuel, a fuel-supply, an inlet to the cylinder in communication with the air-supply and with the fuel-valve, , a passage from the air supply to the cylinder in communication with the fuel-distributing valve & a cut-oil substantially as described.” You can check US patent # 608845, filed 1895 that granted in 1898.
History tells that was not only one man’s idea rather it was of many other’s different ideas that developed over time.
In 1806 Nicephore Niepce & Claude brothers developed internal combustion engine that known to be first one & the first fuel injection system as well.
George Brayton in 1874 developed a 2-stroke oil fueled constant pressure engine that is Known as “Ready Motor”. That ready motor engine used a metered pump that supply fuel to an injection device, the oil was vaporized by air & burned as it entered the cylinder in which. Brayton’s Ready Motor engines were installed in 2 submarines, several boats, a bus and a rail car. Diesel engines of early days also use a similar cycle.
On 1894 at February 17, the redesigned engine ran 88 revolutions in one minute, Augsburg’s stock rose by 30%, demands for a more efficient engine. Diesel rushed to have a prototype running engine in 1896. The 1st engine that was ready for testing, built on December 31, 1896 which is much different engine than the one they had started with previously. In 1897 they succeed, the engine runs 16.93 kW and efficiency of 16.6% and he is granted the patent of engine. Diesel had become a millionaire by 1898.