船用柴油机实时缸压的混合建模研究

Real-time cylinder pressure data is an important parameter to realize cycle control of diesel engine, and it is too expensive to measure it directly by pressure sensor. Model estimation method and indirect measurement method are two common ways to obtain cylinder pressure data, but these two methods guarantee their accuracy at the expense of real-time. In order to obtain real-time and accurate in-cylinder pressure, a hybrid modeling method of Marine diesel engine based on data-driven model and dynamic model is proposed. Firstly, Wiebe combustion parameters are calibrated by historical operating cylinder pressure data, and a diesel data-driven model based on the nonlinear relationship between the operating parameters and Wiebe combustion parameters is constructed. Then, by analyzing the dynamic characteristics of the crankshaft connecting rod system, a diesel engine dynamic model based on instantaneous speed reconstruction of cylinder pressure is constructed. Finally, the weighted average method is used to build a hybrid model of data-driven model and dynamic model. The results show that the hybrid modeling method can obtain more accurate cylinder pressure data without loss of real-time performance.