Abstract
Oil has diesel and gasoline. The same engine is also divided into diesel engines and gasoline engines. Each car is refueled; diesel vehicles can not add gasoline, and gasoline vehicles can not add diesel. But some people think, "After all, gasoline and diesel are both oil and can burn, so why can't they be interchangeable?" This is a fascinating question, and today, we will discuss this topic; understanding the principle can give us a deeper understanding of diesel engines.
First of all, it is concluded that the reason why the two fuels are not interchangeable is the characteristics of the two fuels and the engine combustion principle; diesel is adapted to the combustion principle of the diesel engine, and gasoline is also adapted to the combustion principle of the gasoline engine, if the engine is interchangeable, the engine can not burn usually.
Characteristics of gasoline and diesel
Gasoline is volatile, but the ignition temperature of gas is relatively high, over 400 degrees Celsius.
Diesel oil does not evaporate but will ignite when the temperature exceeds 200 degrees Celsius.
Isn't it amazing what you see here? Because diesel ignites at such a low temperature, it's harder to catch fire than gasoline. I remember seeing a video of these two beakers using the same petrol and diesel. Match it up and put it in two cups. As a result, the gasoline caught fire, but the flame was only on the surface of the gasoline liquid, not on the surface of the gasoline liquid, and all the gas burned simultaneously, and the diesel did not catch fire at all.
What are the facts? The principle is simple: neither gasoline nor diesel burns in a liquid state, but in a gas state. For example, in the video of burning gasoline in a burning cup, the match ignites gasoline because it is volatile. The beaker looks like liquid gasoline but already has much gasoline vapor. This part of the gasoline vapor comes into contact with the oxygen in the air and immediately catches fire when the match reaches a high temperature. The liquid gasoline in the beaker continues to evaporate at high temperatures, keeping the flame burning.
Diesel oil is non-volatile, so the liquid diesel oil in the beaker is almost non-volatile, and even a burning match can hardly ignite it.
Gasoline engine ignition mode
Spark plugs ignite gasoline engines because the temperature of the arc center of the spark plug can reach thousands of degrees Celsius, and it is easy to ignite gasoline and diesel. But the spark plug arc is tiny, the core of the hot part is also minimal, and the duration is concise. Which fuel is more likely to ignite with a spark plug? Of course, gas! Because gasoline is volatile, it is easier to form a uniform mixture of oil and gas when gasoline enters the cylinder. These mixtures surround the spark plug electrode, and as long as the spark plug ignition arc can ignite the mixture near it in an instant, and then this part of the fire continues to ignite other combinations, the combustion of the engine is complete. The combustion rate is speedy, so the speed of gasoline engines can be very high.
Diesel is not volatile; when the engine works, the diesel in the cylinder cannot form a sufficient concentration of mixed gas with the air, and the spark plug is difficult to ignite.
Diesel engine ignition mode
When the diesel engine is working, the piston compresses the air to produce high temperatures, and the injector then injects diesel fuel into the cylinder at very high pressure. Diesel oil is atomized into a tiny fog particle. The diesel droplets in the outermost layer first evaporate, mix with the air, and then burn at high temperatures. The high combustion temperature promotes further evaporation, mixing, and combustion of other diesel oil.
As can be seen, diesel burns much more slowly in the cylinder than gasoline. The nozzle burns as it sprays. Therefore, the piston of a diesel engine cannot run too fast, or there will not be enough time left to burn. Thus, the speed of diesel engines is generally reasonable.
Therefore, whether a diesel engine uses diesel or gasoline is determined according to the diesel engine's working mode and fuel characteristics.
Can gasoline and diesel engines be refueled?
Suppose the gasoline engine uses pure diesel. It can not be started in the cold car state because the diesel viscosity is significant, not volatile. The gasoline engine injection pressure is low, so the diesel injected into the cylinder can not be atomized and evaporated well. In that case, the spark plug point can not be used, and the natural operation cannot be performed.
However, if a small amount of diesel is added to the gasoline because there is enough gasoline, it can also form a mixture that is ignited through a spark plug, and the combustion can be sustained, so the engine can still work at this time. However, if the diesel content is too large, the diesel will quickly evaporate at the high temperature of the cylinder. At the same time, due to the low ignition point of diesel, it is easy to burn and ignite gasoline at the same time, without waiting for the spark plug to ignite at the same time, that is, knock, causing engine damage.
Adding a small amount of gasoline does not affect the work of the diesel engine, at this time the cylinder is still diesel compression ignition, and the gasoline is burned together. But if you have too much gas, you get in trouble. Because when the diesel engine works, the diesel injected in the cylinder gradually burns, and the pressure in the cylinder is uniform. When there is too much gasoline, diesel combustion will cause gasoline to burn in an instant, and the pressure in the cylinder will suddenly rise, which is easy to damage the engine.
Conclusion
Both diesel engines and gasoline engines require precision, efficiency, and higher fuel requirements, so we know this principle and do not quickly try to swap fuels.
If you still need clarification about diesel engines, you can contact me, and I will provide you with professional answers and high-quality diesel engine Spare parts.
Related Reading:How to check whether the diesel engine coolant is sufficient?