重型甲醇发动机排气门烧蚀分析及改进

Analysis and Improvement of the Exhaust Valve Ablation for the Heavy Duty Methanol Engine

主要针对重型甲醇发动机在台架可靠性试验过程中出现排气门烧蚀的故障,采用材料检测、微观检测、宏观检测、排气门和座圈匹配情况、排气门温度场分析等手段,并结合整机试验和整机拆解分析,包括排气门烧蚀出现的试验工况、对应缸盖底平面局部杂质多等现象。提出了从排气门本身、整机EGR率提升燃烧控制、甲醇蒸发改善燃烧杂质、增加刮碳环缸套控制杂质分布等措施。经试验验证,改进效果良好。

Aiming at the failure of exhaust valve ablation in the process of bench reliability test of heavy methanol engine,the means of material detection,micro detection,macro detection,exhaust valve and seat ring matching and exhaust valve temperature field analysis are used.Combined with the whole machine test and whole machine disassembly analysis,including the test conditions of exhaust valve ablation,exhaust valve and seat ring matching,exhaust valve temperature field analysis,and there are many impurities in the bottom plane of the corresponding cylinder head,some optimization measures are put forward,such as improving the combustion control from the exhaust valve itself,the EGR rate of the whole machine,improving the combustion impurities by methanol evaporation,increasing the carbon scraping ring cylinder liner to control the impurity distribution,etc.The test results show that the improvement effect is good.