특성 방법을 이용한 Fuel Rail 압력맥동 특성 해석 프로그램 개발

In the return less fuel rail system of MPI engine, pulsation damper is commonly mounted for the purpose of diminution of pressure pulsations and jarring noise. But, pulsation damper is too expensive for all the advantage. Therefore, the studies are on the increase to develop fuel rail to diminish pulsations with integrated damping effect. This paper deals with numerical approach using method of characteristics to design fuel rail to reduce pulsations with self-damping effect. Primarily, the pressure pulsation characteristics is investigated with aspect ratio of cross section, wall thickness, and materials of fuel rail. Secondarily, sweep test simulation of fuel rail for in-line engine is performed as engine speed increases to find out certain engine speed where pressure pulsation peak is observed. A high aspect ratio or thin wall is found to absorb the pressure pulsations effectively. The fuel rail made of aluminum is effective for reduction of pressure pulsation than that of low-carbon steel. Pressure pulsation peak is observed at the vicinity of certain engine speed where single-injector oil hammer simulation predicts that resonance would occur.