Prediction of the transient emission characteristics from diesel engine using temporal convolutional networks

Abstract

In order to predict the transient emission characteristics from diesel engine accurately and quickly, a novel prediction model, based on temporal convolutional networks (TCN) that incorporates the dilated convolutions and residual connections, was presented in the paper. Firstly, 1800 samples from the World Harmonized Transient Cycle (WHTC) were employed to train and validate the model. A Random Forest algorithm was used to select six top important variables as inputs to reduce the data dimensionality. Then the effect of model hyperparameters on the prediction performance was discussed and the optimal hyperparameter combination was obtained by a particle swarm optimization (PSO) algorithm. The optimized TCN model showed a coefficient of determination value (R2) above 0.972 for training dataset and 0.941 for validation dataset, respectively. The root mean squared error (RMSE) and the mean absolute error (MAE) were relatively low. Finally, the measured data from World Harmonized Steady Cycle (WHSC) was used to test model, and the average R2 value of 0.936 demonstrated that TCN model has excellent robustness and generalization. Moreover, a comparative investigation between TCN model and other advanced algorithms, including BP, GBRT, XGBoost, RNN, LSTM and Transformer, was also conducted. The result showed that TCN model has not only higher accuracy, but also has less computing time. This demonstrates that it is a promising method to predict the emission characteristics of diesel engine.