船用中速天然气发动机起动过程的控制策略

摘要

船用天然气发动机起动过程预燃室过量空气系数受转速影响大.针对ACD320型船用中速天然气发动机台架试验出现的起动困难问题,通过计算分析获得发动机起动过程预燃室过量空气系数随主燃气喷射量、转速的变化规律.采用AVL Fire软件模拟发动机主燃室和预燃室在不同过量空气系数下的缸内燃烧和动力特性,并据此制定起动过程的控制策略,经发动机台架试验验证,证实了起动控制策略的有效性,从而为解决船用中速天然气发动机起动困难的技术问题提供参考.%The excess air coefficient in the per-chamber,which is related to ignition,is influenced by the cranking speed in natural gas marine engines during its starting process.In order to solve the starting issue of ACD320 medium speed natural gas marine engine on a test bench,the variation of the excess air coefficient in the pre-chamber changes with the gas injection quantity and the engine speed was investigated by simulation.Firstly,the combustion process and engine performances were analyzed by AVL Fire software in different excess air coefficient conditions in the main and per-chambers.Based on these simulation results,a control strategy of the starting process was established for the medium speed natural gas marine engine.Then,the starting control strategy was verified on the engine test bench.The results indicate that the proposed control strategy can give reference to the starting problem of the ACD320 natural gas marine engine.