DETERMINATION OF THE OPTIMAL MODES OF THE EXHAUST GASES MANAGEMENT PROCESSES OF MARINE DIESELS

Abstract

Determination of optimal modes of exhaust gas management processes of marine diesel engines The exhaust gas recirculation system of a marine diesel engine, the use of which ensures a decrease in the concentration of nitrogen oxides in the exhaust gases, is considered. Features of high- and low- pressure exhaust gas recirculation systems, as well as the exhaust gas bypass system, are highlighted. The purpose of the research was to determine the optimal modes of operation of ship exhaust gas management systems. At the same time, the combination of two factors was taken as optimality criteria - the maximum reduction of nitrogen oxide emissions (as one of the main sources of environmental pollution) and the minimum increase in specific fuel consumption (as the main economic indicator of the operation of marine diesel engines). Experimental studies carried out on the Wartsila-Sulzer marine diesel engine 16V32, the recirculation system of which made it possible to vary the degree of exhaust gas recirculation in the range of 0...21 %, determined that: increasing the degree of exhaust gas recirculation contributes to increasing the environmental friendliness of marine diesel engines, which is expressed in reduction of emissions of nitrogen oxides up to 28.25...29.83 % compared to the operation of a diesel engine without the use of a gas recirculation system; with an increase in the degree of exhaust gas recirculation, the efficiency of the operation of marine diesel engines deteriorates, which is expressed in an increase in specific fuel consumption, while in some operating modes and a certain degree of bypass, the increase in specific fuel consumption reaches 11.00...12.30 % compared to the operation of a diesel engine without using gas recirculation systems. As the optimal proposed modes of operation of the exhaust gas recirculation system corresponding to 12...15 % degree of exhaust gas recirculation, which ensure a reduction in nitrogen oxide emissions in the range of 16.6...26.6 %, while the increase in specific fuel consumption is in the range of 2.17...4 .81 %.