Numerical examination of high-pressure fuel injection in common rail injector based on hydro-mechanical model

Abstract

The design of a high-pressure common rail injector is critical to the efficient operation of a high-power internal combustion engine. In this study, we develop a one-dimensional model of a hydro-mechanical system to examine the dynamic behavior of the injector. We use the validated model to investigate the effects of the operating conditions and internal structural parameters on the rate of injection, and analyze its dynamic response under single- and multi-injection conditions. The results show that the rail pressure and energizing time have different effects on the delays in opening and closing, and a sufficiently long energizing time is needed to lift the needle to a fully open position. A smaller semi-angle of the seat of ball valve might initiate faster injection. The diameter of the hole, half-angle of the seat, and half-angle of the cone of the needle valve all have positive effects on the rate of injection. The critical dwell time increased with the rail pressure under an energizing time of 0.5 ms, while the opposite result is obtained under energizing times of 1.0, 1.5, and 2.0 ms.