In addition, they have a good fuel economy and the fuel is cheap, making them economical and a popular choice for passenger cars as well.
In order to look at the characteristics of these diesel engines in detail, let's first compare gasoline engines and diesel engines.
The basic structure of both gasoline and diesel engines are almost the same, the combustion cycles are the same. So what are the differences between gasoline and diesel engines ?
Let's look at each in detail.
- Differences in the combustion method
In gasoline and diesel engines, the method with which fire is applied to burn the fuel is quite different.
In gasoline engines, a spark ignites the fire.
In diesel engines, the fuel burns through self-ignition.
Self ignition is the same as pouring cooking oil into a pan, setting a fire under it, and leaving it.
As the temperature of the oil rises, it self ignites and begins to burn. This is the biggest feature of diesel engines. - Differences in the fuel used
Diesel engines used for automobiles use diesel fuel, while gasoline engines use gasoline. Diesel fuel has a higher flash point than gasoline, as well as a lower ignition point.
In other word, gasoline will catch fire with a fire applied to it even at low temperatures, while diesel fuel will not at normal temperatures under the same conditions. The diesel fuel will be the first to ignite on its own when raising the temperature of the fuel itself.
For this reason, ignition occurs in gasoline engines using spark plugs, while in diesel engines heat is applied to the diesel fuel directly for self-ignition.
In diesel engines, heat is generated by compressing air. In self ignited diesel engines, it is necessary for the fuel to ignite easily, and so diesel fuel with good ignitability is convenient.