High-power Marine Diesel Engine No_x Emission Test Calculation And Prediction Methods

Due to the relatively high thermal efficiency and operation reliability, Diesel Engines will still be the main engine in the near future. Considering the deteriorating environmental problem caused by the emissions from ships, people pay more and more attention to the pollution problems of Marine Diesel Engines. Under this situation, IMO Issued the ANNEX VI of MARPOL Convention, which has been carried out since January 1, 2000.Research points out that the three key factors, which determine the NOX emissions, are maximum peak temperature, rich oxygen concentration and the duration in which combustion products stay at high temperature zone. Thereby this paper puts forward four ways to reduce NO, emissions: reduction of the highest combustion temperature, fuel emulsification, Exhaust Gas Recirculation and Selective Catalytic Reduction.According to the MARPOL Convention, NO, emissions are defined as per engine power of NOX mass flow rate. The only method to get NOX mass flow rate is to know NOX concentration in the exhaust and the exhaust mass flow rate. This paper discusses the computational method to get exhaust mass flow rate by carbon/oxygen balance method.Besides the traditional computational method, this paper also demonstrates the possibility of applying BP Neural Network to predict NO, emissions from Marine Diesel Engines. Verified by experimental data, BP Neural Network has proved to be a satisfactory method in the field of NOX emissions prediction.By pointing out that ambient pressure should take the place of scavenging air temperature in the formula of NOX correction factor KHDIES, a new and more reasonable KHDIES has been brought forward.At the end of this thesis, the fundamental equipments' principle as well as measurement process of NO, emissions from Marine Diesel Engines are briefly introduced.