High Quality Diesel Fuel Injector Nozzle Dlla160pn135

In the actual working process of the injector, the flow coefficient of the nozzle is not only affected by the movement of the needle valve, but also by the structure of the flow field inside the nozzle. For a diesel engine, the fuel injector directly extends into the cylinder, and the high heat load and the drastic change of the ambient pressure change the movement of the needle valve and the cavitation at the outlet of the nozzle. And because the working environment of the fuel injector is extremely harsh, it is directly exposed to the combustion chamber, and the carbon deposits generated by the oxidation and polymerization of the oil film at the nozzle hole accumulate in the nozzle hole, resulting in a change in the flow coefficient and affecting the health of the fuel injector. Therefore, realizing the instantaneous on-line monitoring of the nozzle flow coefficient of the injector during the needle valve movement can effectively carry out real-time health assessment and fault diagnosis of the injector, and provide a basis for advanced fuel injection quantity control strategies.

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In different stages of needle valve movement, there are significant differences in the flow coefficient of the nozzle. When the needle valve is continuously at the maximum lift position, the effective flow area of the nozzle is continuously at the state of maximum flow area, and the fuel injection volume hardly changes, while the flow coefficient of the nozzle changes the most when the needle valve is opened and seated. Usually, the single injection time is about 1ms, and the needle valve is mostly in a moving state rather than at the maximum limit.