摘要
为提高航空煤油在点然式发动机中的燃烧热效率,改善发动机爆震及拓宽发动机负荷范围,以3号航空煤油(RP-3)为基础燃料,基于一台单缸水冷、压缩比可调、4冲程点燃式发动机结合高压共轨缸内直喷技术,开展了单双点火、不同负荷、压缩比、喷射压力、喷射时刻和两次喷射策略下航空煤油燃烧特性的试验研究。结果表明,在原机压缩比为10的条件下,将直喷汽油改为直喷航空煤油后,由于航空煤油的抗爆性差、雾化困难、燃烧速率慢等理化特性,发动机的动力性损失约50.0%,油耗增加约60.0%,循环波动也大幅增加;相比于单点火,双点火可使缸内平均有效压力提高,燃烧相位提前,循环波动降低;为了抑制高压缩比下的爆震倾向,可通过降低压缩比来拓宽负荷范围,恢复原机功率。随着压缩比的降低,有效平均压力(BMEP)持续增大,当压缩比为6时,最大转矩可达39.5 N·m,功率恢复至原机的88.0%。同时耦合高压及两次喷射策略,随着喷射压力的增大,有效燃油消耗率(BSFC)减小约30.0%,经济性有所提高。相比于单次喷射,采用两次喷射策略可降低油耗,提升缸内有效平均压力,提升燃烧效率,最终可实现发动机燃用航空煤油的性能接近原机水平,最大负荷达原机的90.0%且油耗增加量不超过15.0%。
In order to improve the combustion thermal efficiency of aviation kerosene in spark ignition engine,suppress knock and broaden engine load range,a single-cylinder water-cooled,four-stroke gasoline engine of adjustable compression ratio was used together with high pressure common rail direct injection technology to study the effects of single and twin sparks,different loads,different compression ratios,different injection pressures,different injection timings,and split injection on the combustion performance of aviation kerosene.The results show that,when the compression ratio of 10 of the base engine is kept and the direct injection of gasoline is replaced by the direct injection of RP-3,the engine power loss is by about 50%,the fuel consumption rises by about 60%,and the cycle fluctuation increases greatly due to the low octane number,poor atomization and slow combustion rate of the aviation kerosene.Compared with the single-spark,the twin-spark can enhance the mean effective pressure in cylinder and combustion phase.In order to avoid the knock tendency at high compression ratios and widen the load range,the compression ratio is reduced,raising the engine power close to the base engine level.With the decrease of the compression ratio,the brake mean effective pressure continues to increase.When the compression ratio is reduced to 6,the optimal torque can reach 39.5 N·m,restoring 88% of the base engine power.Meanwhile,the effective fuel consumption can be reduced by about 30% by coupling high pressure and split injection strategy,improving fuel economy.Compared with the single-injection,the split injection strategy can reduce the fuel consumption,increase the mean effective pressure in cylinder,and promote the combustion efficiency,which enables the engine using aviation kerosene to achieve the performance close to the base engine level.
作者
刘昌文
李杰
刘丰年
华剑雄
周磊
卫海桥
LIU Changwen;LI Jie;LIU Fengnian;HUA Jianxiong;ZHOU Lei;WEI Haiqiao(State Key Laboratory of Engines,Tianjin University,Tianjin 300072,China)
出处
《内燃机工程》
EI
CAS
CSCD
北大核心
2019年第5期8-15,共8页
Chinese Internal Combustion Engine Engineering
基金
装备预研基金重点项目(6140311040101)~~
关键词
航空煤油
高压共轨
双点火
压缩比
爆震
aviation kerosene
common rail system
twin-spark
compression ratio
knock
