[工学]在喷雾引导直喷汽油缸内流混合气的形成和燃烧过程的分析.docVIP

Analysis of the In-Cylinder Flow, Mixture Formation and Combustion Processes in a Spray-Guided GDI Engine Sung-Jun Kim, Young-Nam Kim and Je-Hyung Lee Hyundai Motor Company Copyright . 2008 SAE International 在喷雾引导直喷汽油缸内流混合气的形成和燃烧过程的分析 ABSTRACT The purpose of this paper is to investigate the air/fuel mixture formation and combustion characteristics in a spray-guided GDI engine using a commercial code,STAR-CD. This engine adopted the outwardly opening injector located in the center of cylinder head, which forms a hollow cone spray. The spray injection was modeled arranging multiple points using random function along the ring-shaped nozzle exit. To predict the breakup of spray, Reitz-Diwakar’s breakup model was used, and the model constants were calibrated against published experimental data in a constant volume chamber. The validated spray models were applied to the analysis of spray behavior and mixture formation process inside the engine combustion chamber under operating condition of ultra-lean mixture (λ≈4). To predict the combustion process, the modified eddy breakup combustion model was applied. The present approach reasonably predicted the spray behavior, the mixture distribution near the spark plug, and flame propagation inside the combustion chamber. The calculated combustion pressure had a good agreement with the engine test results. Furthermore, the variations of the geometries of intake port and combustion chamber, the split injection parameters, and compression ratio were evaluated. The result shows that the enhanced tumble flow can deteriorate the mixture distribution of the hollow cone spray, and therefore decreases the burning rate. Also, the influence of injection timing and compression ratio on the quality of the stratified mixture at the spark was well predicted. 摘要 本文的目的是研究空气/燃料混合气的形成和在喷雾引导GDI发动机使用的是商业代码，STAR-CD的燃烧特性。这台发动机采用向外开放的喷油器位于缸盖的中心，形成一个空心锥形喷雾。为蓝本安排使用随机函数沿环形喷嘴出口的多点喷射注射。赖茨，Diwakar预测喷雾解体，解体模型，模型校准常数，对在一个恒定体积室发表的实验数据。喷雾模型验证，适用于喷射发动机燃烧室超稀混合（λ≈4