With the advantages of ultra-low emissions of oxides of nitrogen (NOX) and high thermal efficiency, the homogeneous charge compression ignition (HCCI) mode applied to marine diesel engine is expected to be one of the technical solutions to meet the International Maritime Organization (IMO) MARPOL73/78 Convention-Annex VI Amendment Tier III requirement. According to the NOX chemical reaction mechanism, taking a marine diesel engine as the application object, the numerical study on the NOX formation characteristics of n-heptane for HCCI combustion process is performed. The results indicate that NO is usually the main component in the generation and emissions of NOX with the n-heptane HCCI mode. The combustor temperature plays more important role in the proportion of NO generation and emission. Compared with the experimental data of conventional marine diesel engine, the emission reduction rate of NOX can achieve an average of more than 95% in using HCCI technology.

Currently, single-frequency Global Navigation Satellite System (GNSS) receivers dominate maritime navigation units due to their simple structure and low cost but usually cannot meet the positioning requirements of Maritime Autonomous Surface Ship (MASS). Herein, a novel adaptive Doppler-smoothed-code Bilateral Kernel Regression (DBKR) method is proposed, which improves pseudorange accuracy in the range domain and then reconstructs observations in the position domain. In the range domain, the Doppler observable is utilised to smooth the pseudorange with an optimal window smoothing width for the BeiDou Navigation Satellite System (BDS) receiver to alleviate ionosphere delay. In the position domain, we elaborate a bilateral kernel regression model to further reduce the positioning drift. The on-line regression process starts with mapping the observation space to Euclidean space and subsequently fusing all observations of the same epoch using the Gaussian Radial Basis Function (RBF). Finally, the experiments under static and dynamic scenarios are carried out, which verify the validity and efficiency of the proposed DBKR method.