The function of fuel injector

The fuel injector is one of the precision parts of the diesel engine. The faults it is prone to include: wear of the cone surface of the needle valve and the needle valve body, wear of the needle valve and the guide surface of the needle valve hole, expansion of the nozzle hole, stuck needle valve, and injector injector. The hole is blocked, the injection pressure is too high or too low, etc.

The fuel injector is one of the precision parts of the diesel engine. The fitting gap between the needle valve and the needle valve body is only 0.002~0.003?mm. The shape of the fuel injector is a very important parameter in the fuel system. It has a great impact on the spray quality, injection form, and fuel and air mixing state. These factors directly affect the emission indicators of the diesel engine. In recent years, in order to meet the increasingly stringent diesel engine emission requirements and obtain better economic performance and emission performance, the following development trends of fuel injectors have emerged:

(1) Increase injection pressure, especially at low speeds;

(2) Increase the number of nozzle holes and reduce the diameter of the nozzle holes;

(3) Variable fuel injection rate, such as pilot injection, etc.

The function of the fuel injector is to atomize diesel fuel under a certain pressure into fine and uniform oil particles, so that the diesel fuel can be well mixed with the air in the combustion chamber. The structural parameters of the fuel injector include the number of holes, hole diameter, cone angle, etc. of the nozzle. It is located at the top of the combustion chamber and is directly exposed to the high-temperature and high-pressure combustible mixed gas. The working temperature is high and the working conditions are poor. Thermal load and mechanical load often cause poor sealing of the needle valve coupling, gas backflow, and even stop working. In addition, the working condition of the injector directly affects the economy, power, emissions, reliability, etc. of the diesel engine. Therefore, it is very necessary to analyze and eliminate common faults of fuel injectors.