Cycle Simulation for the Performance Prediction of a High Pressure Unit Injection System of a Diesel Engine

디젤엔진용 고압분사 유닛인젝터의 성능예측을 위한 사이클 시뮬레이션

In this study, a cycle simulation program of a Unit-Injection(UI) system was developed to estimate the injection performance of newly designed injection system. A fundamental theory of the simulation program is based on the conservation law of mass. Loss of fuel mass in the system due to leakage, compressibility effect of the liquid fuel and friction loss in the control volume was considered in the algorithm f the program. For the evaluation of the simulation program developed, the experimental result which was offered by the Technical Research Center of Doowon Precision Industry Co. was incorporated. Two main parameters; the maximum pressure in the plunger chamber and total fuel mass(kg) injected into the engine cylinder per cycle, were measured and compared with the simulation results. It was found that the maximum error rate of the simulation result to the experimental output was less than 3% in the rated rotational speed (rpm) range of the plunger cam.