Friends who drive for a long time and pay attention to fuel consumption basically have a feeling: adding 95 gasoline seems to be more resistant to burning than adding 92 gasoline; some people also think that the degree of gasoline resistance of CNPC, Sinopec, and CNOOC is also different. In addition, many people think that the current No. 92 gasoline is becoming more and more unbearable. There is still some controversy in the first two points, but the last point has become a consensus among most people.
▲What is gasoline?
To figure out the above problems, we must first know what gasoline is. Gasoline and diesel are both petrochemical products and are mixtures composed of a variety of hydrocarbons . If distinguished from the components, it means the difference in carbon content per unit molecule. Gasoline has the characteristics of low carbon value , low density and volatile. Diesel has the higher carbon content, which has relatively high calorific value, relatively large density and is not easy to volatile. Of course, petrochemicals have many other products, which are also divided according to the molecular carbon content. The products are all good things and are well-deserved industrial treasures.
Speaking of this, we should all understand: neither gasoline nor diesel is pure, but a mixture, and its carbon content is only a range, not a fixed value. This leads to, although they are both called gasoline, their compositions often vary greatly. This difference naturally leads to the characteristics of gasoline.
▲What kind of gasoline is more resistant to burning?
Gasoline is a mixture of smaller molecules in petroleum products. The molecules of the hydrocarbon-based compound contain about 5-10 carbon atoms (12-22 diesel), that is, the molecules with all 5 carbon atoms are gasoline, all 10 carbon atoms are molecules, and they are also gasoline.
Some basic chemical knowledge knows that the more carbon atoms in a single molecule, the greater the heat generated after full combustion (the kind that will emit thick smoke means that there is not enough oxygen in the air and the carbon is burned out). In other words, gasoline with 10 carbon atoms will be more resistant to burning than gasoline with 5 carbon atoms (this pure gasoline certainly does not exist), and has a stronger power.
The "calorie elasticity" among them is the core reason why many people think that different gasolines have different burn resistance. This thing is not easy to test. People know what the average carbon content of the unit molecules of the gasoline they add. The three oil tycoons won’t let you test it. They are all so transparent. How can they “get out”?
▲Does the gasoline label affect the degree of burn resistance?
In principle, the gasoline label only represents the octane number of gasoline. It evaluates the anti-detonation ability of gasoline. No. 95 gasoline has better anti-detonation ability than No. 92 gasoline. It can be used stably on an engine with higher compression than and more advanced combustion technology, and has no effect on whether it is burn-resistant. Most media and engineers explain this, that's all.
Does the gasoline label really affect the degree of burn resistance of gasoline? Personally, they have different opinions. First of all, we know that the thermal efficiency of of automotive internal combustion engine is basically below 40%, and the few can exceed 40%. The remaining 60% are heat loss and mechanical loss... cannot be effectively used (heating is still a little bit useful in winter). Of course, part of the mechanical loss is also taken away by the engine vibration and noise, and the share is quite large. Then the problem is that if you add No. 92 gasoline, although it can be turned on, it will not affect the engine life, but after all, it will be weaker in the anti-detonation, which will lead to greater mechanical losses (vibration, noise), which indirectly affects the engine's thermal efficiency to a certain extent. If less energy can be used effectively, the degree of burn resistance will naturally be weakened.
In addition to this, theoretically, there are differences between No. 92 gasoline and No. 95 gasoline only in the value of octane , but the author is also skeptical whether this is true. In fact, as a gasoline additive, the calorific value of octane is higher than the calorific value of gasoline, which will affect the average calorific value of gasoline to a certain extent.
In addition, the quality of petroleum/diesel produced by different origins also varies greatly, including sulfur content, molecular type and distribution, which will not only affect the degree of burn resistance, but also affect power output and exhaust emissions.The quality of oil produced in China's oil fields is not as good as that of , Middle East, , Europe and the United States, which involves the ratio of olefins, aromatics, and benzene. As for process optimization and equipment upgrade, the three tycoons of China Petroleum, haha, I really can't complain.
▲Why is gasoline becoming more and more intractable?
Gasoline is becoming more and more unburned, which has become the consensus of most domestic car owners. The answer is very simple. In order to save energy and reduce emissions, domestic gasoline has gradually moved closer to "small molecule". In the past, the average carbon content of unit molecules in gasoline was 5-10. I dare say that now it is basically hovering around 5-7. If such gasoline is resistant to burning, it will be a ghost.
Haha...
Even, some regions have begun to fully use ethanol gasoline, which means adding alcohol to gasoline. The unit molecule contains only two carbon atoms, and the other one is an oxygen atom. Can the calorific value of this thing be compared with hydrocarbons (large molecules with only carbon and hydrogen)?
Finally, let’s talk about oil-to-gas cars. Most taxis are like this, and they burn natural gas, which saves money. The main component of natural gas is methane, an organic substance with the simplest structure. It has only one carbon atom and four hydrogen atoms per unit molecule. It has a natural low calorific value, so any oil-to-gas car will have a significant power attenuation and will not be resistant to burning. Of course, there are also benefits. Natural gas does not require atomization, does not require any advanced injection system or high compression ratio to fully burn, and the utilization rate of fuel is higher than that of gasoline (liquid).
