喷射控制策略对增压直喷汽油机燃烧和性能的影响

来源期刊:中南大学学报(自然科学版)2020年第3期

论文作者:段雄波 李洋洋 刘敬平 谭永浩 解云坤 罗宝军

文章页码:805 - 816

关键词:喷射时刻;喷射压力;二次喷射;分配系数;增压直喷汽油机

Key words:injection timing; injection pressure; two-stagnation injection; distribution coefficient; turbocharged gasoline direct injection engine

摘    要:对1台车用增压直喷乙醇汽油机进行试验,研究不同喷射策略包括喷射次数、喷射时刻、喷射压力及分配系数对发动机性能的影响。研究结果表明:对于单次喷射模式,喷油时刻为上止点前300°时性能最佳,此时,有效热效率最高达35.17%,指示热效率最高达37.51%;随着喷射时刻推迟,50%燃烧位置 曲轴转角 往上止点推移,燃烧持续期缩短;喷油压力扫描试验结果表明该工况的最佳喷射压力为12 MPa,此时,有效热效率最高达34.35%,指示热效率最高达37.01%;在二次喷射模式下,随着第一次分配系数下降, 逐渐远离上止点且燃烧持续期逐渐延长,有效热效率随着分配系数减小而降低,而指示有效压力的循环变动率和有效燃油消耗率随之升高;燃油消耗率最大偏差达62.48 g/(kW·h),燃油消耗率最高降低20.19%,因此,合理控制和优化喷油控制策略能提高增压直喷汽油机的燃烧质量并提高其性能。

Abstract: The effect of different injection controlling strategies,including injection number, injection timing,injection pressure and injection fuel mass repartition on performance characteristics of turbocharged gasoline direct injection engine fueled with gasoline and ethanol blend, were experimentally investigated. The results show that in terms of the single injection mode, 300° before top dead center is the optimal injection timing,besides,the brake thermal efficiency and indicated thermal efficiency reaches 35.17% and 37.51%,respectively. The 50% combustion location shifts to the top dead center and the combustion duration shortens with the retarding of the injection timing. Furthermore, 12 MPa is the optimal injection pressure for the single injection mode. The brake thermal efficiency and indicated thermal efficiency are 34.35% and 37.01%,respectively.In terms of second injection mode,50% combustion location stays away from the top dead center and the combustion duration prolongs with the increase of the second fuel mass repartition.Besides,with the increase of the second fuel mass repartition, the brake thermal efficiency decreases while the cycle of variation of indicated mean effective pressure and the brake specific fuel consumption increase.The maximum deviation value of the brake specific fuel consumption is 62.48 g/(kW·h) and the fuel economy decreases by 20.19%. Therefore, optimizing the fuel injection strategy can improve the combustion and performance of the turbocharged gasoline direct injection engine.

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