【摘要】 HCC I燃烧不能大量应用到商业产品的核心障碍是其着火时刻和燃烧速率的控制问题.为此,研究了甲醇对柴油类燃料(正庚烷)均质压缩自燃特性的抑制效果及其对燃烧持续期和排放特性的影响.在正庚烷中加入1000/~4000/的甲醇(体积分数),通过气口喷射进入单缸发动机实现HCC I燃烧.考察了几种燃料在1 800 r/m in各种当量比下的燃烧特性和排放特性.研究表明,在正庚烷中加入2000/~3000/的甲醇后,低温反应时刻推迟,低温放热率降低,导致整个着火时刻推迟到上止点附近,燃烧持续时间适当延长,发动机当量比范围拓宽,但是过高比例的甲醇会引起低负荷范围的显著缩小.在排放特性方面,甲醇比例低于2000/时,CO和HC排放与正庚烷相当,但是3000/~4000/甲醇正庚烷燃料的HC就有明显升高.更多还原

【Abstract】 The effects of methanol additive on auto ignition and combustion rate of HCCI combustion was investigated using diesel type fuels（n-heptane）.N-heptane and 10⁰/₀—40⁰/₀（volume percentage） methanol/n-heptane blend fuels were injected into the intake port.The combustion characteristics and emissions of HCCI combustion for different methanol/n-heptane blend fuels at（1 800 r/min） were recorded and analyzed.The results show that,with the introduction of methanol in n-heptane,both the maximum and minimum accepted operating equivalence ratioes increase,but the maximum engine load could not be further expanded for 40⁰/₀ and above methanol/n-heptane fuel.The ignition timing of low and high temperature reaction delay and the maximum heat release at the low temperature decreases with the increase of the methanol addition in n-heptane.For（20⁰/₀） and 30⁰/₀ methanol/n-heptane blend fuels,the combustion timing of the high-temperature reaction occurs between（-5° CA） ATDC and 5° CA ATDC,and the combustion events accomplished during the expanding stroke.With regards to the emissions,10⁰/₀ and 20⁰/₀ methanol addition shows little effect on CO and HC emissions,but substantially increases for 30⁰/₀ and 40⁰/₀ methanol/n-heptane blend fuels.NO_x emissions are very low for all fuels at all operating conditions.更多还原