基于压缩空气起动的柴油机瞬态特性仿真研究

Simulation research on transient characteristics of diesel engine based on compressed air starting

利用一维仿真软件GT-Power建立大功率船用柴油机稳态模型,在此基础上对系统进行改进,增加高压气瓶、管路、空气分配器、起动空气阀模块,构建基于压缩空气分配器起动的柴油机起动过程瞬态模型,并试验验证2种模型的准确性。系统分析了环境压力、滑油温度和起动系统参数等对柴油机起动过程性能的影响,结果表明,该压缩空气系统驱动柴油机起动时间为2.6 s,能够实现连续6次起动,满足柴油机起动性能要求;选取压缩空气压力为30 bar、气瓶容积为350 L、空气管路直径为36 mm、供气起始角为-5° CA能够有效提高柴油机起动性能;从100%负载突加突卸计算结果来看,该柴油机瞬态调速率达到4.67%,不超过5%的指标要求,转速恢复到额定转速±2%的恢复时间增加至0.57 s,满足指标要求。

A steady-state model of a high-power marine diesel engine was established based on the one-dimensional simulation software GT-Power.On this basis,the system was improved by adding modules for high-pressure gas cylinders,pipelines,air distributors,and starting air valves.A transient model of the diesel engine starting process based on com-pressed air distributor starting was constructed,and the accuracy of the two models was verified through experiments.A sys-tematic analysis was conducted on the effects of environmental pressure,lubricating oil temperature,and starting system parameters on the starting process performance of diesel engines.The results showed that the compressed air system can drive the diesel engine to start for 2.6 s and can achieve six consecutive starts,meeting the starting performance require-ments of diesel engines;The increase in environmental pressure increases the starting exhaust resistance,significantly in-creases the starting time,and reduces the number of consecutive starts.Choosing a compressed air pressure of 30 bar,a cylin-der volume of 350 L,an air pipeline diameter of 36 mm,and a supply starting angle of-5°CA can effectively improve the starting performance of diesel engines.From the simulation results of sudden loading and unloading at 100%load,it can be seen that the transient speed regulation rate of the diesel engine reaches 4.67%,which does not exceed the indicator require-ment of 5%.The recovery time for the speed to recover to±2%of the rated speed is increased to 0.57 s,meeting the indicat-or requirements.