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In piston engines, static compression ratio is determined using the cylinder volume when the piston is at the top and bottom of its travel. The compression ratio is the ratio between the maximum and minimum volume during the compression stage of the power cycle in a piston or Wankel engine.
1952 Shell Oil film showing the development of the diesel engine from 1877. The diesel engine, named after the German engineer Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the diesel engine is called a compression-ignition engine (CI engine).
However, a real diesel engine will be more efficient overall since it will have the ability to operate at higher compression ratios. If a petrol engine were to have the same compression ratio, then knocking (self-ignition) would occur and this would severely reduce the efficiency, whereas in a diesel engine, the self ignition is the desired ...
In Europe, diesel cetane numbers were set at a minimum of 38 in 1994 and 40 in 2000. The standard for diesel sold in European Union, Iceland, Norway and Switzerland is defined by standard EN 590. Since 1 January 2001 EN 590 demands a minimum cetane index of 46 and a minimum cetane number of 51. Premium diesel fuel can have a cetane number as ...
Engines using the Diesel cycle are usually more efficient, although the Diesel cycle itself is less efficient at equal compression ratios. Since diesel engines use much higher compression ratios (the heat of compression is used to ignite the slow-burning diesel fuel), that higher ratio more than compensates for air pumping losses within the engine.
The Wärtsilä RT-flex96C is a two-stroke turbocharged low-speed diesel engine designed by the Finnish manufacturer Wärtsilä. It is designed for large container ships that run on heavy fuel oil . Its largest 14-cylinder version is 13.5 meters high, 26.59 meters long, weighs over 2,300 tonnes , and produces 80.08 megawatts .
Modern engines have compression ratios in the range 8 to 11, resulting in ideal cycle efficiencies of 56% to 61%. Diesel cycle: trucks and trains In the Diesel cycle used in diesel truck and train engines, the fuel is ignited by compression in the cylinder.
Piston moves from crank end (BDC, bottom dead centre and maximum volume) to cylinder head end (TDC, top dead centre and minimum volume) as the working gas with initial state 1 is compressed isentropically to state point 2, through compression ratio (V 1 /V 2). Mechanically this is the isentropic compression of the air/fuel mixture in the ...