Home > News > Content

The Cycle Principle Of Diesel Engine

Oct 20, 2017

The working process of diesel engine is the same as that of petrol engine, and each work cycle also undergoes four trips, such as air intake, compression, reactive power and exhaust gas. But because diesel fuel is diesel, its viscosity is bigger than gasoline, it is not easy to evaporate, and its spontaneous combustion temperature is lower than gasoline, so the formation of combustible mixture and ignition mode are different from gasoline engine.Diesel Engine

The diesel engine is inhaling pure air during the intake stroke. At the end of the compression stroke, diesel fuel oil injection pump will increase the oil pressure to more than 10MPa, through the injector injected into the cylinder, in a very short time with the compressed high temperature air mixture, forming a combustible mixture gas. Because the compression ratio of diesel engine is high (generally 16-22), the air pressure in cylinder can reach 3 at the end of compression. 5-4.5MPa, at the same time temperature up to 750- 1000K (and the gasoline engine at this time of the mixed gas pressure will be 0. $number. 2MPa, temperature up to 600-700k), significantly more than diesel ignition temperature.Diesel Engine

As a result, diesel fuel burns spontaneously after it has been injected into the cylinder and mixed with air in a very short period of time. The air pressure in the cylinder rises rapidly to the 6-9mpa, and the temperature rises to the 2000-2500k. Driven by high-pressure gas, the piston moves downward and drives the crankshaft to rotate, and the exhaust gas is discharged into the atmosphere by the exhaust pipe.Diesel Engine The general diesel engine is driven by the engine camshaft, which is transported to the fuel tank of each cylinder by means of a high-pressure oil pump. This kind of oil supply method should change with the engine speed change, does not have the optimum oil supply quantity under each rotational speed. The common rail injection system of electronically controlled diesel engine, which is now becoming more and more popular, can solve this problem well.Diesel Engine

Compared with gasoline engine, diesel engine has low fuel consumption rate (average 30% lower than gasoline engine), moreover, the diesel oil price is low, therefore the fuel economy is good, the engine speed is generally lower than the petrol engine, the torque is bigger than the petrol engine, but its quality is big, the noise is big at work, the cost of manufacturing and maintenance is high, and the emission is worse than the petrol engine. But with the development of modern technology, these shortcomings of the diesel engine are gradually overcome, now not the high-end cars have started to use diesel engines.Diesel Engine