Research On Heavy Oil Emission Used For Medium Speed Diesel Engine

Since industrialization, trade communication between countries increase frequently, Theshipping industry has been rapid growth, making the problem of the ship emissions is more andmore serious. At the same time our country with less light fuel store capacity, but heavy oil resourceis rich, the development of heavy oil not only can create directly economic benefits, but alsoenhance national energy security.In recent years, However, the atmospheric quality worse and worse, haze is more and moreserious, environmental problems are being more and more people’s concern and attention.Governments and organizations have formulated the strict emission regulations, to curb emissionsof environmental impact. In this background the research to reduce emissions of heavy fuel oil intothe urgent moment.DN8340is the research object in this paper to reduce the NOx emissions and soot. zerodimensional combustion model is set up by AVL-BOOST, and engine data can be compared toensure the results. So it can provide data for the establishment of three-dimensional combustionmodel.By AVL-Fire ESE diesel module build engine combustion chamber and the division of grid,because the AVL-Fire combustion model need to set the boundary conditions, but some data isdifficult to obtain by the experimental method or measurement error is large, but through theAVL-BOOST you can get the initial data. Marine diesel engine in order to save fuel, most drivingnear the maximum torque, while DN8340the maximum torque point near the75%load, in order toclose to the actual situation, This thesis result is in engine rated speed650r/min, under75%loadsimulation. By the simulation of different EGR and fuel injection advance Angle influence on dieselengine emissions.The research show that when the beginning of heavy oil spray, NOx almost no generation,when the temperature is reached1800k, have less NOx generation, but more than2200k, a lot ofNOx generation. By studying the different EGR, when reduced the EGR, The reaction rate isaccelerated, NOx finally constant in a value, the mass fraction of it would not decrease along withthe expansion of the combustion chamber work stage.But at the time of the heavy oil is sprayed intothe cylinder, soot began to a large number of generated, and the rate at which generated quicklyreached maximum, then reduced the reaction rate, the reasons for this are fuel injection cylinder,began in a non-uniform combustion of oxygen, resulting in the generation of large amount of carbon smoke, but diesel engine is an oxygen-enriched combustion process, so as the reactionprogresses, soot and oxygen combustion reaction, were reduced carbon emissions of smoke.Research different injection advance Angle, reduced the injection advance Angle, the heavy oilis sprayed into the combustion chamber, ignition temperature is close to ignition point, so lead to oiland gas is not very uniform mixing, It will affect the fuel economy and power performance. And Itwill make heavy oil ignition starting point backwards, so it could reduce the pressure and thetemperature in the cylinder and reduce NOx emissions.Burning diesel oil and heavy oil were compared, found that heavy oil combustion NOxemission is higher than diesel, and the temperature in the cylinder is lower than diesel.Above all you can appropriate increase EGR and reduce the injection advance Angle to reduceNOx emissions of engine. Finally adjust EGR is0.3, fuel injection advance Angle is8°CA, otherparameters constant. comparing the original engine and optimized the performance of the engine,the NOx emissions compared to the original engine greatly reduced after optimization, NOxemissions reduced from9.68g/kWh to0.88g/kW, conform to the IMO Tier Ⅲ emissionsrequirements.