It must be the big lorries, engineering trucks and coaches that drive down the road with their backsides billowing black smoke and rumbling, doing heavy, dirty work.



In the domestic car market, although some passenger cars will use diesel power, but it is only limited to some hard SUV models, such as the ordinary family cars we drive daily rarely use diesel power, why is this?



Since all the cars around us are using gasoline as fuel, some friends have to ask whether that means gasoline is more than diesel. Speaking of which, let's first give you a popular science about the production of diesel and gasoline.



For example, according to the 2018 crude oil processing data released by Sinopec, gasoline output was 61.16 million tons, an increase of 7.24% year on year. Diesel output reached 64.72 million tons, down 3.06 percent year on year.



From the published data we can see that the processing capacity of diesel is more than 3 million tons more than gasoline, which is deviated from our inherent cognition. China's diesel production is not a lot of good, so what are the diesel used to do?



First of all, transportation, storage and postal services account for a proportion in the diesel consumption structure. For example, the "three direct routes and one terminal" running on the road every day, and the express trucks of SF Express and Jingdong are the big users of diesel consumption.



Secondly, industry, agriculture, forestry, animal husbandry, fishery, construction and living consumption are inseparable from the figure of diesel oil. Because it is more suitable for heavy machinery, it is in high demand, and there is no spare diesel fuel for passenger cars to use.



And in some special time nodes, when the supply of diesel fuel is tight, there will be oil panic. At this point, I also have a feeling that my uncle's family has a diesel version of H3. Every time I go to the gas station during the New Year, the side of adding diesel not only needs to wait in a long queue but also sometimes will be limited.



When it comes to this, we have to mention the difference between diesel and gasoline. First of all, diesel and gasoline are made from crude oil that looks "black".



During the process, the hydrocarbon chains of crude oil are broken down and sorted. Diesel differs from gasoline in the length of this "chain".



Short chains form gasoline, while long chains form diesel. Shorter chains are more likely to burn, so diesel is less likely to ignite quickly than gasoline.



In addition, the ignition of diesel and gasoline engines is very different. We all know that traditional cars have four strokes -- intake, compression, combustion, and exhaust.



The operation process of a gasoline engine is to mix and compress the air with gasoline and then burn it through the ignition piston, while the operation process of a diesel engine is to mix the pure air with the diesel fuel injected directly into the cylinder and then burn it for work.



Because diesel engines rely on compression combustion without ignition system, and its auxiliary electrical appliances are less, low speed, so the aging of parts, wear speed is less than gasoline engines. In the failure rate and service life has a more significant congenital advantage.



Diesel engine was invented by Rudolf Diesel in 1892. In memory of this inventor, Diesel is referred to by his family name Diesel. Diesel engine is also called Diesel engine.



Gasoline engine in the compression process of its air and gasoline mixture ratio is 7:1, the pressure in the cylinder between 8-18bar, the temperature is -600 degrees Celsius. Diesel engine air and diesel mixture ratio is 18:1, the cylinder pressure can reach 30-50bar, the temperature can reach 700-900 degrees Celsius.



The compression ratio of the engine is different, resulting in different thermal efficiency. We all learned in junior high physics that the higher the compression ratio, the higher the thermal efficiency. Therefore, compared with gasoline engine, diesel engine has a higher thermal efficiency, which means that it is more fuel efficient.



In addition, the diesel engine has the characteristics of low rotation and high torsion, and it will perform better when dealing with some complex road conditions, climbing and high load conditions. High torque is like saying that a person has strength, and if you look at all the construction machinery that runs on diesel fuel, which one does not rely on strength.



Diesel engines are also safer than gasoline engines, and the danger of a liquid can be determined by its flash point. What is the flash point? The temperature at which a liquid can vaporize and ignite.



The higher the flash point, the higher the safety. The flash point of general gasoline is -50 ~ -20℃, and the flash point of diesel oil is above 55℃, so the safety of diesel oil is higher than that of gasoline, and compared with gasoline, diesel oil is not volatile, whether it is easier to store or transport.



Having said all that, there is a downside. Diesel engines do not perform as well at acceleration and high speeds as gasoline engines, which are used in supercars such as Ferrari and Lamborghini.



Diesel engines also produce more carbon dioxide emissions, with seven litres of diesel producing as much carbon dioxide as 10 litres of petrol.



As we mentioned above, diesel engines have a higher compression ratio, which is limited by the pressure in the cylinder, so they are heavier and more expensive than gasoline engines.



In addition to the emission is not environmental protection, high manufacturing cost, noise and other problems, in the winter temperature is lower in the environment is also easy to play the fire, buy diesel vehicles to send quilts, may be a good way of marketing. Diesel generator



Since the diesel engine has more outstanding advantages than the gasoline engine, then why we do not mainly push the diesel car in China? There are a lot of factors behind it. Let me tell you.



One of the main reasons is that the sulfur content of domestic diesel was particularly high. As long as it can be divided into two aspects, one is because the imported crude oil itself belongs to the crude oil of high sulfur and high acid value. Second, early China's refining technology is relatively backward and immature.



In the process of refining, because the corrosion of sulfur for refining equipment is very serious, in order to improve the quality of refined oil, reduce the amount of vulcanization, it is necessary to increase the difficulty of the process, the difficulty is up, the cost of refining is up, the price of diesel generator and final diesel oil will also be adjusted. Want quality but want to save money? It doesn't exist.