某重型车用V8柴油机燃烧系统优化设计

针对某重型车用V8柴油机的燃烧室廓形和喷油器凸出高度进行了设计.优化设计方案由5个燃烧室廓形和5个喷油器凸出高度组成,选择了ESC稳态排放循环中的A100,C100,A25工况以及最大功率工况作为优化设计的工况点,利用AVL-Fire软件在这4个典型工况点上对各设计方案的缸内燃烧过程进行了模拟计算,采用了一个综合目标评价函数来评判不同方案对循环功、NOx和Soot的综合影响,从100个算例的计算结果中筛选出最优的燃烧室廓形和喷油器凸出高度.和原机相比,优化的燃烧系统在高负荷工况可使油耗下降1.4%,Soot排放降低14%~30%.

Optimization Design of the Combustion System for a V8 Heavy Duty Diesel Engine

The combustion chamber profile and nozzle protrusion for a V8 heavy duty diesel engine were optimized .5 kinds of combustion chamber profiles and nozzle protrusions were designed and the verification conditions were the rated power point and the A100 ,C100 and A25 points of ESC .Based on the 4 typical conditions ,the in-cylinder combustion process for each scheme was simulated and calculated with AVL-Fire software ,a comprehensive object evaluation function for evaluating cycle power ,NOx and soot emission was built ,and the optimal combustion chamber profile and nozzle protrusion were selected ac-cording to the results of 100 cases .Compared with the original combustion system ,the newly optimized system realized 1 .4%decrease in fuel consumption and 14%-30% reduction in soot emission at high load .