中文摘要：

定义了放热率曲线的'时序系数',以表征燃烧过程的时序特征.试验表明:引燃柴油量相同时,随着当量比增加,热效率先升高后降低;总碳氢(THC)排放降低;滞燃期延长;燃烧重心先接近上止点后远离上止点;第一放热率峰值先出现在燃烧始点附近,然后接近燃烧重心;第二放热率峰值逐渐与第一放热率峰值'合二为一',且两者均先升高后降低;'时序系数'增加,时序特征愈加不明显.当量比相同时,随着引燃柴油量增加,热效率升高;燃烧相位前移;放热速率加快.另外,随着引燃柴油量增加,在较低当量比时THC明显降低,但在较高当量比时却没有明显变化.

英文摘要：

Time-sequenced coefficient of heat release rate curve was defined to quantize the time-sequenced characteristic. Results show that, for the same pilot diesel amount, with the increase of equivalence ratio, engine thermal efficiency increases first and then decreases, total hydrocarbons (THC) is decreased, ignition delay is increased, the crank angle of heat release curve center moves to the top dead center (TDC), and then leaves the TDC. First peak of heat release rate occurs near the start of combustion, and then it moves to the crank angle of heat release curve center. Second peak of heat release rate joins first peak of heat release rate gradually. Both values of the first and second peaks of heat release rate increase first and then decrease. Time-sequenced coefficient increases and time-sequenced characteristic becomes unobvious. At same equivalence ratio, with the increase of pilot diesel amount, engine thermal efficiency is increased. Combustion phase moves to the TDC and heat release rate is increased. In addition, at relatively low equivalence ratio, THC emissions decrease significantly with the increase of pilot diesel amount, while it has little change at relatively low equivalence ratio. ? 2015, Chinese Society for Internal Combustion Engines. All right reserved.