滚流比对缸内直喷汽油机混合气形成及燃烧的影响  

Effect of Tumble Ratio on Mixture Formation and Combustion of GDI Engine

作　　者：韩文艳[1,2] 许思传[1] 周岳康[3] 张弘[3] 任健康[3] 

机构地区：[1]同济大学汽车学院,上海201804 [2]中北大学机电工程学院,山西太原030051 [3]上海汽车集团股份有限公司技术中心发动机部,上海201804

出　　处：《内燃机学报》2012年第6期499-505,共7页Transactions of Csice

摘　　要：用FEV评价方法对两种进气道稳态流动特性进行了对比,适当减小气道与气门座夹角,可使滚流比提高约20.3%,而流量系数降低了11.8%.用FIRE软件对使用两种滚流比气道发动机的缸内流动进行了仿真,分析了滚流比对气流运动、混合气形成及燃烧的影响,并对其进行了试验验证.结果表明,在低速和高速工况下,高滚流比可以提高燃烧速率,改善燃烧稳定性,使燃油消耗率降低约10%.同时,高滚流比发动机由于具有较强的气流运动及缸内湍动能,混合气分布更加均匀且燃烧更充分,因此HC和CO排放也相应降低,而较高的缸内温度使得NOx排放在低速时增加比较明显.The steady flow performances of two intake ports with different tumble ratio were compared by FEV evaluation methodology. Appropriately reducing the angle between intake port and valve seat in- creases the tumble ratio by 20.3% but decreases the coefficient efficiency by 11.8%. Using FIRE software, the airflow of engines with two intake ports was simulated and the effects of tumble ratio on charge movement, mixture formation and combustion were studied. Test verification was also carried out. Results show that under the low and high speed conditions, high tumble ratio can enhance burning rate and improve combustion stability, decreasing fuel consumption by 10%. Due to strong airflow movement and turbulent kinetic energy under high tumble ratio condition, mixture forms more uniformly and bums more completely, which decreases HC and CO emissions. But NOx emissions increase obviously at low speed due to relatively higher cylinder temperature.

关 键 词：缸内直喷汽油机 滚流比 混合 燃烧 燃油经济性 

分 类 号：TK412[动力工程及工程热物理—动力机械及工程]