某船用柴油机低速性能优化

Performance optimization of low-speed operation for a marine diesel engine

为解决某船用柴油机怠速合排以及急加速工况时冒黑烟问题,分析涡轮增压器对柴油机低速性能的影响,仿真分析柴油机低速工况进气不足原因;优化配气相位,并对优化后的柴油机进行台架测试和实船验证。结果表明:柴油机低速工况进气不足的原因为废气倒流;优化配气相位后,柴油机低速工况时的充气效率提高,进气量增加,缸内燃烧得到改善,低速合排以及急加速工况增压器的响应速度提升,怠速合排以及急加速瞬间烟色显著改善,怠速合排转速恢复时间缩短至5 s以内,满足拖轮用户使用需求。

In order to solve the problem that the diesel engine emits black smoke seriously in case of sudden speed-up and when it is attached to the propeller quickly during idling,the influence of turbocharger on low-speed performance of diesel engine is analyzed,and the reason for insufficient intake of diesel engine at low speed is analyzed through simulation method.The valve phase is optimized,and verified by testing bench and ship.The results show that after valve phase is optimized,the volumetric efficiency is improved during low-speed operation,and the intake air is increased,so the in-cylinder combustion is enhanced effectively,then the response speed of turbocharger is improved in case of sudden speed-up and when diesel engine is attached to the propeller quickly during idling,the smoke of idling and sudden speed-up is optimized significantly,and the recovery time of idle speed is shortened to less than 5 s,which finally meets the demand of tug customer.