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Abstract
The quality of the fuel injection system mainly depends on the fuel injection characteristics and atomization characteristics of the system. The structural parameters of the fuel injector play an important role in the flow condition of fuel injection, thus affecting the atomization characteristics of fuel injection. The atomization characteristics of the fuel injection system are seriously affected by the nozzle structure. In this paper, the influence of the nozzle diameter and the chamfering at the nozzle entrance on the atomization characteristics of the system is analyzed. The results show that the diameter of the jet hole increases, the area of the negative pressure increases, the cavitation intensity decreases, the flow coefficient of the nozzle relatively decreases, and the fuel injection speed decreases, but the range of the oil beam and the spray cone angle increase. With the increase of the chamfer angle at the entrance of the nozzle, the area of the negative pressure decreases, the cavitation intensity relatively decreases, but the uniformity of fuel injection speed increases, the flow coefficient of the nozzle increases, the average fuel injection speed increases, and the fuel oil range and the spray cone angle increase. The back pressure has no obvious effect on the internal flow and overall atomization of the nozzle. The response surface method (RSM) is used to obtain the response surface function of the mass flow and the chamber pressure. The analysis shows that in order to increase the mass flow rate, it is necessary to increase the spray hole diameter as much as possible. In order to increase the chamber pressure and reduce the cavitation, it is necessary to reduce the diameter of the spray hole, the top radius of the valve core and the diameter of the pressure chamber ball as much as possible. It provides theoretical and practical guidance for the structural optimization design of fuel injection system.