The main difference between a diesel engine and a gasoline engine is that the ignition mode caused by the physical properties of the fuel is different, and the thermal effect and economy are different. When a gasoline engine is started, the gasoline spray mixes with air into the cylinder and is then ignited by the spark plug when it is compressed to near end. Therefore, the compression ratio of the gasoline engine cannot be very high, so the working pressure of the gasoline engine is relatively small, and the operation is stable and the noise is small. But its economy and thermal efficiency are smaller than diesel engines.
When a diesel engine starts, it first compresses the air in the cylinder, causing its temperature to rise sharply. When the air temperature exceeds the self-ignition point of the diesel, the diesel is injected, and the main diesel and the air-mixed diesel are spontaneously ignited at the same time, so the diesel engine does not need a spark plug ignition system. Since diesel has a relatively high auto-ignition point and is not restricted by deflagration, the compression ratio of diesel engines is very high. It operates under very high pressure. Diesel engines are not as stable as gasoline engines and are noisy. But its thermal efficiency and economy are better than gasoline engine. Gasoline engines are generally made of lightweight materials due to their low working pressure. It has the characteristics of small size, light weight, easy to start, stable operation and fast speed. The diesel engine has a large compression ratio and the cylinder operates under a large working pressure, so the manufacturing is relatively firm and bulky, but its power is large and the economy is relatively high.
Combining the above characteristics, it can be seen that the stability and noise caused by the high working pressure of the diesel engine are not as good as that of the gasoline engine, and the economy is more economical than that of the gasoline engine. There must be many people who are obsessed with diesel engines. But there are still people who will choose a gasoline engine roller, so further in-depth analysis is being made. The diesel fuel mixture is carried out in the combustion chamber, and the diesel fuel injected at high pressure enters the combustion chamber, and after compression and self-ignition, it works in the way of fuel injection and combustion. This method inevitably causes uneven fuel gas mixture, and local oxygen deficiency occurs during the combustion process. The fuel is carbonized under high temperature and anoxic state, resulting in insufficient fuel combustion. We often see the black smoke coming out of the diesel engine is formed in this way. The molecules of gasoline are small and easy to mix with air and have the characteristics of unfavorable separation in the mixed state. The gasoline and the mixture are relatively uniform, and there is basically no overcooked and liquid oil droplets.
