船用中速柴油机燃油系统升级改造仿真分析

针对大量采用机械式喷油系统的船用中速柴油机经济性和排放水平比较落后，特别是在低速低负荷工况下，不满足排放法规和船东要求的问题，以某型船用中速柴油机为对象，在燃烧室结构参数不变基础上，将原有的燃油喷射系统改造为高压共轨燃油喷射系统，分析喷油器结构参数和控制参数对柴油机缸内喷雾、混合气形成和燃烧过程的影响规律.仿真计算结果表明，优化后的高压共轨式柴油机能满足Tier II排放法规，低负荷下发动机的经济性提高近8%，全工况范围内NOx排放降低近30%.
Marine medium-speed diesel engines equipped with mechanical injection systems have the problem of economy and emission performance, especially the deficiency to meet the emission regulations and ship-owners' demands at low speed and low load conditions. To solve this problem, a typical marine medium-speed diesel engine was taken as study object, the original mechanical fuel injection system was retrofitted to high pressure common-rail fuel injection system with same combustion chamber structural parameters. The effect of injector structural parameters and control parameters on oil spray, mixture formation and combustion process were analyzed. Simulation result shows that the retrofitted engine complies with IMO Tier II emission regulation, and has more than 8% economy performance enhancement at low load and near 30% NOx emission reduction at the whole operation range.