일차원 전산 해석을 통한 가변 밸브 시스템의 효과 연구 및 가변 밸브 전기 점화 엔진의 최적화 연구

Realization of variable valve actuation technology brought great improvements on the fuel economy and emissions of modern spark ignition engines. Many kinds of VVA systems were introduced, but still quantitative researches about those systems are insufficient. And employment of these techniques also yields additional control parameters and exponential increase of research cases, which can't be easily resolved by experimental research. Given this, employment of additional methodologies like simulation or design of experiment is essential to make an effective approach comparing the efficiency of various VVA systems quantitatively and the optimization of the CVVT-VVL (Continuous Variable Valve Timing. Variable Valve Lift) spark ignition engines. One dimensional simulation model is a powerful tool which is applicable to the entire region of interest of engine operation and it provides reliable insight to the behavior of the CVVT-VVL engines under varying valve timing and valve Jift. Detailed investigation covering numerous operating points can be conducted in a relatively short time compared to the experimental research and it opens new possibilities to the optimization procedure of these new engines.