흡배기압과 실린더압의 동시 측정을 통한 다기통 CAI 엔진의 흡배기 유량 및 실린더 내 잔류가스 Online 예측 모델의 개발

CAI (Controlled Auto Ignition) engine has properties of higher efficiency and lower emission than conventional gasoline engine. However, CAI combustion control is difficult, because the combustion is mainly controlled by in-cylinder residual gas fraction (RGF) which cannot be controlled directly. In-cylinder RGF is usually controlled using variable valve actuating System (VVA), by adapting low lift cam, short valve duration and negative valve overlap. So, it is very important to predict RGF accurately and quickly in developing CAI engine. In this study, an online model for predicting RGF using measured intake, exhaust, and cylinder pressure has been developed. By measured three points of dynamic pressures as pressure boundaries of pipe inlets and outlets using labview DAQ system. This model could calculate directly RGF in 10 seconds without solving complex and computationally expansive energy equations during engine experiment. Calculations of mass flowrate and RGF in various CAI combustion conditions were done, and the results were compared with GT-Power results.