A Study Of Calculation And Measurement Of NOx-Emission From Marine Diesel Engines

In this paper, the emission control on marine diesel engines that is more and more severe is discussed in the context of the addition of annex VI to MAPOL 73/78. The inevitability of emission test on-board is brought forward.One new calculational method that is different from IMO' methods is deduced by analyzing the foundation mechanism of various deleterious gases and their chemical reaction equations. By application of the method, the nitrogen oxides (NOx) emission per effective power (g/kWh) can be accurately calculated without solving non-linear equations and taking the risk of falling across not convergent equations. The error analysis of the method is carried out. The error coefficients of atmosphere, exhaust gas, fuel oil and engine's various parameter are deduced. By comparing error coefficient each other, the degree of which parameters' measure precision impacts on the eventual result is easily made out. So improving measure methods can be of pertinence: ameliorating mainly the measure precision the parameters that impact on the final result more greatly; other parameters may be tested cursorily or just reckoned. Afterwards, the example validating of the method is carried out. The data from WARTSILA NSD W6L20C marine diesel engine's bed test are calculated and analyzed; the result indicates that the method is as accurately as the IMO's methods. The tiny difference between the method and WARTSILA NSD Ltd. 's methods is also analyzed. The method presented in this paper is believed to be more accurately. The result calculated by this method can reflect the actual emission level more truly. Lastly, the special condition of nitrogen oxides (NOx) measure in on-board test is discussed. The mainly deference between on-board test and bed test is pointed out. Several available measure methods of exhaust gas, engine and fuel oil's parameter are also brought forward.