The degree of difficulty in vaporizing a liquid substan […]
The degree of difficulty in vaporizing a liquid substance is called the evaporation of the substance.
The process of burning gasoline in the combustion chamber of a gasoline engine is carried out in a vapor state, that is, the vaporization process of gasoline precedes the combustion process. Therefore, before entering the gasoline engine cylinder, the gasoline must first be vaporized by the chemical oil and mixed with the air.
The speed of modern gasoline engines for automobiles is very high, and the time for gasoline to evaporate and form a mixture in the engine is very short. In order to form a uniform combustible mixture in such a short period of time, in addition to the technical conditions of the gasoline engine, the ambient temperature and pressure, and the technical level of the driving operator, it is mainly determined by the evaporability of the gasoline itself.
The more evaporating the gasoline, the easier it is to vaporize and the more uniform it is with the air. Because of good vaporization, the uniformly mixed combustible mixture has a fast burning speed and complete combustion, so that not only the engine is easy to start, accelerates, and the conversion is sensitive and soft under various working conditions, but also reduces mechanical wear and reduces gasoline consumption. Therefore, gasoline engines require that gasoline must have good evaporation, but not too strong. Because the evaporative gasoline is used in hot summers and in plateaus and high mountains where atmospheric pressure is low, it is easy to cause "gas resistance" in the fuel supply system of gasoline engines, and even oil supply interruption. In addition, evaporation loss will increase during storage and transportation.
Gasoline with very low evaporability can not form a good mixture, which will not only make the gasoline engine difficult to start, but also accelerate slowly, and the unvaporized suspended oil particles will also make the engine work unstable and the fuel consumption rate rise. If the unburned oil particles adhere to the cylinder wall, it will also damage the lubricating oil film and even break into the crankcase to dilute the lubricating oil, thereby causing damage to the engine lubrication and causing an increase in mechanical wear.