디젤기관용 분사밸브 형상에 따른 분사특성

Abstract

Injection technology is one of the important technologies in a diesel engine. Many studies have done on the injection system. In this study, the fuel chamber geometry, the orifice ratio and the needle lift of the injection valve of a diesel engine for generating electricity are varied, tested and simulated. In the test, the injection pressure, duration and spray shapes are obtained with pressure transducer, needle lift sensor and high speed camera. The result shows that the nozzle hole size has influence on the rail pressure and injection duration sensuously. In the simulation using average 55,000 grids, static and dynamic pressure on outlet surface and velocity vector are obtained. Decrease of the static pressure at the place O(between needles) and increase of the dynamic pressure on the outlet surface are occurred owing to the rise of the nozzle hole diameter, high increase rate of the dynamic pressure with changing nozzle diameter exposed at needle lift 0.4mm. In the consequence, the data of the experimental test and simulation were identical and the highest dynamic pressure of the outlet was occurred at needle lift 0.4mm and nozzle hole diameter 0.328mm.