增程式电动汽车用LPG直喷发动机燃烧过程的数值解析
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摘要
提出一种以LPG为燃料的适用于增程式电动汽车发电机组的二冲程缸内直喷发动机喷雾-壁面复合引导式燃烧系统。在采用纹影实验法对计算方法的可行性进行验证的基础上,分别对不同喷油时刻、不同曲轴转角的缸内混合气形成及燃烧情况进行了数值解析。结果表明:在起动-过渡运转工况(2 000 r/min、20%负荷)下,喷油开始时刻为45°CA ABDC、曲轴转到20°CA BTDC时,缸内能形成较为稳定的均质混合气。在20°CA BTDC时点火,放热率峰值最高,且峰值一般出现在上止点附近,燃烧特性最好。
In this paper,a spray-wall combination guided combustion system of two-stroke direct injection engine for LPG generator with LPG fuel is proposed. On the basis of verifying the feasibility of the calculation method by using the shadow test method,the formation and combustion of the mixture in the cylinder at different injection timing and crank angles were analyzed numerically. The results show that when the crankshaft rotates to 20°CA BTDC,the fuel injection start at 45° CA under the condition of start-over operation( 2 000 r/min,20% load),will have comparatively stable homogeneous mixture formation. When ignited at 20°CA BTDC,the peak value of heat release rate is the highest,and the peak value appears near top dead center,with the best combustion characteristics.
In this paper,a spray-wall combination guided combustion system of two-stroke direct injection engine for LPG generator with LPG fuel is proposed. On the basis of verifying the feasibility of the calculation method by using the shadow test method,the formation and combustion of the mixture in the cylinder at different injection timing and crank angles were analyzed numerically. The results show that when the crankshaft rotates to 20°CA BTDC,the fuel injection start at 45° CA under the condition of start-over operation( 2 000 r/min,20% load),will have comparatively stable homogeneous mixture formation. When ignited at 20°CA BTDC,the peak value of heat release rate is the highest,and the peak value appears near top dead center,with the best combustion characteristics.
引文
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[13]张博彦,雷艳,周大森.LPG/汽油双燃料发动机排放性能研究[J].农业机械学报.2005.36(3):34-36.
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[2]周世斌.用液化石油气做汽车燃料[J].应用能源技术,1997(03):25-27.
[3]孙建成.液化石油气汽车的应用[J].汽车研究与开发,1997(6):32-36.
[4]许伯彦,耿德强,齐运亮,等.液态LPG燃料喷射过程的数值解析及可视化试验[J].内燃机学报,2009,27(2):146-152.
[5]周重光,严兆大,王希珍.空燃比对LPG发动机排放特性影响的研究[J].内燃机工程,2002.23(5):23-26.
[6]ZHANG X and ROMZEK M.Computational Fluid Dynamics(CFD)Applications in Vehicle Exhaust Systemp[C].SAE Paper2008-01-0612.
[7]刘牮,吴煌全,刘凌.LPG发动机性能优化试验研究[J].农机化研究,2008.(9):147-149.
[8]顾维东,杨延相,蔡晓林,等.FAI二冲程直喷汽油机缸内流场的多维数值模拟研究[J].内燃机学报,2007,25(2):150-156.
[9]水嶋教文ほか.LPGおよびガソリンの層流予混合燃焼機構の相違がSIエンジンの燃焼速度に及ぼす影響[C].日本自動車技術会学術講演会前刷集,67-09:11-16,JSAE 20095156.
[10]屈碧波.LPG缸内直接喷射发动机三维模型仿真[D].上海:上海交通大学.2007.01.01
[11]李西秦,徐兆坤,邵千钧,等.LPG喷射形式对发动机性能的影响[J].内燃机工程,2004,25(2):43-45
[12]Lee S W,Tanaka D and Kusaka J et al.Two-dimensional laser induced fluorescence measurement of spray and OH radicals of LPG in constant volume chamber[J].JSAE Review,2002,23(2):195-203.
[13]张博彦,雷艳,周大森.LPG/汽油双燃料发动机排放性能研究[J].农业机械学报.2005.36(3):34-36.
[14]周重光.LPG发动机三维燃烧模拟计算与试验研究[D].杭州:浙江大学,2003.
[15]蔡晓林.FAI二冲程缸内直喷汽油机的研究[D].天津:天津大学,2005.
[16]BAKER P,WATSON H.MPI Air/Fuel Mixing for Gaseous and Liquid LPG[C].SAE Paper 2005-01-0246.