秦 静 ^{1, 2}，张启锐 ^{1, 2}，裴毅强²，李 翔²，彭 忠²，彭志军²
AuthorsHTML:秦 静 ^{1, 2}，张启锐 ^{1, 2}，裴毅强²，李 翔²，彭 忠²，彭志军²
AuthorsListE:Qin Jing ^{1, 2}，Zhang Qirui ^{1, 2}，Pei Yiqiang²，Li Xiang²，Peng Zhong²，Peng Zhijun²
AuthorsHTMLE:Qin Jing ^{1, 2}，Zhang Qirui ^{1, 2}，Pei Yiqiang²，Li Xiang²，Peng Zhong²，Peng Zhijun²
Unit:1. 天津大学内燃机研究所，天津 300072；
2. 天津大学内燃机燃烧学国家重点实验室，天津 300072
Unit_EngLish:1. Internal Combustion Engine Research Institute，Tianjin University，Tianjin 300072，China；
2. State Key Laboratory of Engines，Tianjin University，Tianjin 300072，China
Abstract_Chinese:基于一台涡轮增压4缸汽油机，全面系统地探究了进气道喷水量对发动机燃烧特性、燃油经济性以及排放特性的影响规律．试验选取发动机3个常用转速(2000r/min、2800r/min和3200r/min)以及具有代表性的中等负荷(50%)，水油质量比μ的选取范围为0～40%．结果表明：随着μ的增加，水的大比热容和高温分解带来的吸热作用的增强，使得缸内平均压力曲线上升趋势变平缓，缸内最高压力和t_α显著降低；滞燃期先基本不变而后延长，CA 50和θ_T先基本不变而后推迟，燃烧持续期逐步缩短．与μ＝0相比，μ＝40%时，在2000r/min、2800r/min、3200r/min下，缸内最高压力分别下降约0.72MPa、0.64MPa、0.94MPa，t_α分别降低30℃、68℃、47℃，CA 50分别滞后3.3°CA、3.1°CA、4.4°CA．燃油消耗率(BSFC)呈现先略有减少而后较明显增加的趋势，μ＝10%是转折点，可降低BSFC约1g/(kW·h)，而μ＝40%时将增加BSFC约3g/(kW·h)．进气道喷水后减少了局部高温和局部过浓区域，有助于明显降低GDI汽油机的NO_x和烟度排放．与μ＝0相比，μ＝40%时，NO_x和烟度的最大降幅高达30%左右．而喷水对CO和HC排放的影响相对较弱，随着μ的增加，CO和HC排放分别呈现缓慢降低和缓慢上升的趋势．GDI汽油机在当量比下采取喷水策略具有节能减排的潜力，工程应用前景广阔．
Abstract_English:Based on a turbocharged four-cylinder gasoline direct injection(GDI)engine，the influence of intake manifold water injection mass on combustion，fuel economy，and emissions was systematically investigated．Three usual engine speeds(2000r/min，2800r/min，and 3200r/min)and a typical medium load(50%)were selected for the test．The range of water-fuel mass ratio was selected as 0—40%．The results showed that with the increase of μ，due to the high specific heat capacity of water and the enhancement of heat absorption from pyrolysis ，the upward trend of the average pressure curve in cylinder became flat，and the maximum cylinder pressure and t_α reduced sig-nificantly．The combustion delay period first remained largely steady and then extended．The crank angle CA50and θ_T first remained largely steady and then delayed，and the combustion duration gradually shortened ．Compared with the conditions of μ＝0，when μ＝40%，at 2000r/min，2800r/min，and 3200r/min，the maximum pressure in the cylinder decreased by about 0.72MPa，0.64MPa，and 0.94MPa，respectively．The t_α was reduced by 30℃，68℃，and 47℃，respectively．The CA50 lagged by 3.3°CA，3.1°CA，and 4.4°CA，respectively．The fuel consumption ratio(BSFC)first reduced slightly and then significantly increased．With μ＝10%as the turning point，the BSFC reduced by about 1g/(kW·h)，while with μ＝40%，the BSFC increased by about 3g/(kW·h)．The intake manifold water injection reduced the local high-temperature and local overconcentration areas，which is conducive to significantly reducing the NO_xand smoke emissions of the GDI engine．Compared with the conditions of μ＝0，the maximum reduction of NO_xand smoke could reachabout 30%when μ＝40%．However，the effect of water injection on CO and HC emissions was relatively weak．With the increase of μ，CO and HC emissions showed a trend of slow decrease and slow increase，respectively．The GDI engine has the potential of energy saving and emission reduction by using the water injection strategy under aratio of equivalence and it has broadengineering application prospects．
Keyword_Chinese:GDI汽油机；进气道喷水量；燃烧特性；排放特性
Keywords_English:GDI engine；intake manifold water injection mass；combustion characteristic；emission characteristic

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