Simulation Study on Performance Prediction of Spark-ignition Engine in Stroke-to-bore Ratio Variation

Abstract

The Paris Agreement was signed in 2015 and will be in effect from 2021. Most of the United Nations Framework Convention on Climate Change (UNFCCC) members joined this agreement and the amount of the Greenhouse Gas (GHG) emissions reductions that they have to pay is increasing. As a part of efforts to reducing GHG emissions and the drop in international oil prices, the demand for high efficiency gasoline engines is increasing. Therefore, many automotive companies are developing gasoline engines and are interested in researching the engine configuration at the early stage of development. However, fundamental research on various engine configurations, especially stroke-to-bore (S/B) ratio has not been conducted sufficiently. In this study, spark-ignition (SI) engine model was developed using zero-dimensional model and the parameters affecting the engine significantly, depending on the change in S/B ratio, were analyzed through valve, engine model. Especially, flame propagation was simulated through the turbulence model and the turbulent flame speed model, and the effect of the flame varying according to the engine configuration and the parameters were analyzed. The friction model was also applied to compare the brake thermal efficiency, which is one of the important engine operating parameters, in combination with the valve and engine model.