Calculation Of Dual-fuel Engine Exhaust Emissions And The Analysis Of Error Factors

With a surge of global ship ownership,the contradiction between oil supply and demand and the environmental pollution problems caused by the exhaust emissions has received the widespread attention of the shipping industry. Diesel/natural gas dual-fuel engine has a promising prospect in the industry due to the change of low cost, flexible use of fuel,low carbon smoke emissions and some other advantages. Before the dual-fuel engine’s emission calculating standard formally introduced, there’s large margin of error exists in the algorithm which converts the fuel to disel.In order to more accurately evaluate the emission level of dual-fuel engine,accurate test of the pollutants in exhaust calculation is particularly important.This paper mainly focuses on the derivation of dual-fuel engine’s emission algorithm and analyzing the influence of parameter measurement error on emission levels.First of all, some errors exist in the simple carbon balance method of GB/T 8190.1-1999 has been modified,and then take it as the main line derives dual-fuel engine emission algorithm.Secondly,converting the dual-fuel to diesel and nature gas, calculating exhaust gas flow value,and analyzing the reasons for the error generated.Thirdly,discussed the influence of the parameters measurement error on the specific emission level, the conclusion is that:The measurement error of fuel composition has little effect on specific value, in the case of low calculation accuracy,it even can be negligible;If the measured value of gas mass flow is smaller,the specific value is smaller too;If the measured value of power is smaller,the specific value is larger;If concentration measured value of some exhaust gas component is smaller,it will lead to its own smaller specific value,the other components’ larger values;Compared with other parameters, the power measurement error has the maximum impact on specific value.Finally,using MATLAB software made a calculation program,which can reflect the emission level of engine.Using it we can calculate the specific emissions value of pollutants,and also compare it with the experimental resultsThe calculation program in this paper can accurately reflect dual-fuel engine emission level,it transformes the emission limit standards into practical tools, all of this have vital significance on the emission test as well as the research work.