米勒循环与EGR耦合对增压柴油机性能的影响

Influence of Miller cycle and EGR coupling on performance of turbocharged diesel engine

以某6缸四冲程两级增压船用柴油机为研究对象,建立两级增压柴油机米勒循环与废气再循环(Exhaust Gas Recirculation,EGR)耦合仿真模型,研究米勒循环和EGR耦合对两级增压柴油机燃油消耗率和NOx排放的影响.结果表明,当米勒度为-40°CA时,燃油消耗率相对原机降低3.5%,NOx排放相对原机降低25.5%;EGR率为30%时,燃油消耗率相对原机增加5.0%,NOx排放降低98.7%;当米勒度为-30°CA与EGR率为20%时,燃油消耗率相对原机仅增加0.1%,NOx排放降低92.7%.

Taking a 6-cylinder,four-stroke,two-stage turbocharged marine diesel engine as the research object,the coupled simulation model of Miller cycle and exhaust gas recirculation(EGR)of two-stage turbocharged diesel engine was established,and the influences of Miller cycle and EGR coupling on the fuel consumption rate and NOemissions of the two-stage turbocharged diesel engine were studied.The results show that when the Miller timing is-40°CA,compared with the original engine,the fuel consumption rate is reduced by 3.5%,and the NOemissions are reduced by 25.5%.When the EGR rate is 30%,the fuel consumption rate is increased by 5.0%and NOemissions are reduced by 98.7%.When the Miller timing is-30°CA and EGR rate is 20%,compared with the original engine,the fuel consumption rate is only increased by 0.1%and NOemissions are reduced by 92.7%.