The essence of diesel and gasoline vehicles is the process of converting the chemical energy contained in diesel and gasoline into heat and mechanical energy through the internal combustion engine. Due to the different performance of diesel and gasoline, the principle and structure of the fuel engine are also slightly different, but the principle of engine operation is still the same, which is composed of four strokes: suction, compression, combustion and exhaust.
Due to the difference in the characteristics of diesel and gasoline, diesel engine and gasoline engine have the following differences:
1. Ignition method.
Because the ignition point of diesel is relatively low, the diesel engine adopts the compression-ignition ignition method. Generally, after the end of the compression stroke, the ignition point of the air exceeds the ignition point of the diesel fuel, and the fuel is injected into the combustion chamber to achieve compression ignition ignition; And because the volatility of gasoline is relatively strong, the spark plug ignition form is adopted, and the saturated oil and gas mixture is discharged into the cylinder at the end of the compression stroke and ignited with a spark plug, and the gasoline engine needs a complex ignition system, so the structure is more complex.
2. The compression ratio is different.
We know that if an engine has a higher compression ratio, then its thermal efficiency will be higher, fuel consumption will be lower, and the compression ratio of the gasoline engine is lower than that of the diesel engine, so the thermal efficiency of the diesel engine is higher. Generally, gasoline engines need to choose gasoline of appropriate grades to prevent knocking, for example, gasoline engines with higher compression ratios often need to fill gasoline with higher grades.
3. The speed and power are different.
We know that the speed of the diesel engine is slower than that of the gasoline engine, but the power is much greater than that of the gasoline engine. Generally, the speed of diesel engine is 1500 to 2500 rpm, while the speed of gasoline engine is much higher than that of diesel engine, which can generally reach about 6000 rpm. This also leads to the fact that diesel cars generally have more gears, such as some heavy vehicles can go up to 16 gears.
4. The scope of application is different.
Diesel engines are generally used in large vehicles such as trucks, construction machinery, etc., and the current common heavy trucks, large off-road vehicles and even common tractors are diesel engines, while gasoline engines are mainly used in small vehicles such as common cars and motorcycles.
Whether it is a diesel engine or a gasoline engine, its working principle is similar, and the essence is the same, which is to convert the chemical energy of fuel into mechanical energy through internal combustion work. Every engine plant is trying to improve thermal efficiency and reduce emissions, but after decades of hard work, engine development is approaching its limit, unless there are new breakthroughs in materials. Of course, the development of pure electric vehicles has pointed to another way out for cars, whether it is the world of fuel vehicles or the world of pure electric vehicles in the future, we are willing to wait and see.