Validation of a zero-dimensional model for prediction of NO_x and engine performance for electronically controlled marine two-stroke diesel engines

摘要

The aim of this paper is to derive a methodology suitable for energy system analysis for predicting the performance and NO_x emissions of marine low speed diesel engines. The paper describes a zero-dimensional model, evaluating the engine performance by means of an energy balance and a two zone combustion model using ideal gas law equations over a complete crank cycle. The combustion process is divided into intervals, and the product composition and flame temperature are calculated in each interval. The NO_x emissions are predicted using the extended Zeldovich mechanism. The model is validated using experimental data from two MAN B&W engines; one case being data subject to engine parameter changes corresponding to simulating an electronically controlled engine; the second case providing data covering almost all model input and output parameters. The first case of validation suggests that the model can predict specific fuel oil consumption and NO_x emissions within the 95% confidence intervals given by the experimental measurements. The second validation confirms the capability of the model to match measured engine output parameters based on measured engine input parameters with a maximum 5% deviation.