The Main Factors Affecting The Combustion Process of Diesel Engines

There are many factors that affect the combustion process. Here, we analyze the fuel injection time, diesel engine temperature and compression ratio, diesel engine load, speed, and fuel supply law. These requirements for the combustion process are interrelated and contradictory. Generator manufacturer Top Power believes that it is necessary to understand the main factors that affect the combustion process of diesel engines in order to correctly use and maintain them.

The main factors affecting the combustion process of diesel engines are as follows:

1. Fuel quality, such as cetane number, viscosity, calorific value, and distillation range. The small and uniform oil particles sprayed from diesel engines can increase the total area in contact with air, which is conducive to complete combustion.

2. The hot state of the cylinder and the temperature and pressure inside the compression endpoint cylinder have a significant impact on the combustion process.

The higher compression ratio adopted by diesel engines is also to increase the temperature and pressure of the gas at the end of compression, in order to shorten the delay period and make the diesel engine work more smoothly. The oxygen density in the air is high, and fuel combustion is relatively fast and safe. When diesel generator manufacturers repair diesel engines, they cannot arbitrarily change the compression ratio.

To ensure reliable ignition and combustion of diesel, the temperature during compression of the diesel engine should exceed the natural temperature of the diesel at that time. Therefore, a sufficiently high compression ratio should be used. As the compression ratio increases, the temperature and pressure at the end of the compression process rise, which accelerates the physical and chemical reactions of diesel. As a result, the compression ratio shortens and the rate of pressure increase decreases in the later stages of ignition, ensuring smooth operation of the diesel engine.

As the compression ratio increases, the combustion pressure and temperature also rise, which will improve the combustion efficiency. At this time, increasing the compression ratio can also improve the low-temperature starting performance of the diesel engine. However, when the compression ratio is too high, it will cause an excessive increase in the maximum combustion pressure and put too much load on the load-bearing components.

3. Fuel injection pattern

The relationship between the capacity in the cylinder and the crankshaft angle becomes the fuel injection law. The fuel injection pattern mainly depends on the cam profile of the fuel injection pump, and is also related to factors such as the structural form of the fuel injector and the size of the high-pressure fuel pipe. For most diesel engines. A reasonable fuel injection pattern should be: at the beginning of fuel injection, the injection speed should be slower to reduce the amount of fuel in the later stage of ignition and ensure smooth operation of the diesel engine; The injection speed should be increased in the middle and later stages of fuel injection, and the injection amount should increase sharply to ensure that most diesel completes combustion in a timely and rapid manner before and after the top dead center, reducing post combustion.

4. The structural forms of combustion chamber, injection channel, fuel injection pump and injector

The influence of the form of the inlet nozzle on the airflow movement and the influence of the structure of the fuel injection equipment on the spray quality will seriously affect the combustion process. The shape of the combustion chamber also has a significant impact on the stroke and combustion of the mixture.

5. Fuel injection advance angle, a reasonable fuel injection advance angle makes the combustion process reasonable, and improves fuel efficiency and power performance.

6. The speed and load of a diesel engine.

As the speed of the diesel engine gradually increases, the compression process takes less time, resulting in reduced air leakage and heat dissipation losses. At the end of compression, the temperature and pressure increase, and the vortex motion of the gas increases, shortening the ignition delay period. The combustion is relatively rapid and complete. However, when the speed is too high, the resistance of the airflow is proportional to the square of the airflow velocity, which has adverse effects on the completeness and timeliness of combustion. Diesel engines should not operate for long periods of time at low and high speeds.

Although the above are the main factors affecting the combustion process of diesel engines, Guangxi generator manufacturer Dingbo Electric believes that these factors are not isolated, but interrelated and cannot be viewed separately.

Dingbo Power was founded in 1974 and is one of the earliest manufacturers of generators and diesel generator sets in China. If you want get more information, please feel free to send email to [email protected] we will pay highly attention on your question.