【摘要】 针对液化天然气(LNG)-柴油双燃料增压发动机采用AVL-Boost发动机性能仿真计算,分析气门重叠期间LNG燃料通过排气门的泄漏及其影响因素。研究结果表明:气门重叠角是排气门LNG燃料泄漏最重要影响因素,LNG泄漏随着气门重叠角的增大而急剧增加,进气提前角和排气延迟角对LNG泄漏的影响基本相同;LNG泄漏量随着增压比的增加而增加,较高增压比时继续提高增压比会导致LNG泄漏量继续增加,但是LNG百分比泄漏量基本不变;对于增压比为1.8~3.0的LNG-柴油双燃料增压发动机(标定转速为1000r/min,进气提前角为50°CA),排气门LNG燃料泄漏量可以达到全部LNG燃料的1%~5%;适当减小排气门直径是减少LNG泄漏的有效措施。更多还原

【Abstract】 For turbocharged engine fueled with LNG-diesel duel fuel,LNG leak from exhaust valve during valve overlap and its effect on engine performance were analyzed with the AVL-Boost(engine performance simulation software).The research result shows that the most important factor of LNG leak from exhaust valve is valve overlap.LNG leak increases sharply when valve overlap increases;intake advance angle and exhaust delay angle have almost the same effect on LNG leak.LNG leak increases with the increase of boost ratio,but the percentage of LNG leak is basically unchanged.LNG leak from exhaust valves is about 1% to 5% of total LNG fuel burned by turbocharged engines with boost ratio of 1.8to 3.0,rated speed of 1000r/min and intake advance angle of 50°CA.A slowdown in LNG leak probably happens by means of smaller diameter of exhaust valve.更多还原