19_燃料喷射期和滚流对液态LPG喷射发动机形成混合气分层构造的影响_山东建工耿德强等.pdf

燃料喷射期和滚流对液态燃料喷射期和滚流对液态 LPG 喷射发动机形成混合喷射发动机形成混合 燃料喷射期和滚流对液态燃料喷射期和滚流对液态 喷射发动机形成混合喷射发动机形成混合 气分层构造的影响气分层构造的影响 气分层构造的影响气分层构造的影响 耿德强，许伯彦 （山东建筑大学机电工程学院，山东 济南 250101 ） 摘要摘要：：本文通过与实验结果对比的方式验证了所提出的计算方法的可行 ，研究了两种不同 摘要摘要：： 进气阀升程曲线下缸内滚流强度和不同燃料喷射时刻对分层混合气形成过程的影响。研究表 明，滚流在压缩行程初期形成，活塞上行到压缩上止点附近时，虽然燃烧室中心区域依然残 存部分滚流，但其它区域滚流已经畸变、破碎成众多小尺度涡流。最大气阀升程较小的进气 过程形成的滚流强度较大，此时配合在吸气行程中后期喷射更容易形成分层混合气构造。 关键词关键词：：稀薄分层燃烧；CFD ；滚流；数值模拟；LPG 关键词关键词：： The Effects of the Fuel Injection Timing and Tumble on the Formation of Stratified Mixture Structure in a Liquid Phase LPG Injection Engine 1 1 GENG De-qiang ，，XU Bo-yan ，， (School of Electromechanical Engineering, Shandong Jianzhu University, Jinan 250101, China) Abstract: The effects of the tumble under two different intake valve lift curves and the different injection timing on the formation of stratified mixture were investigated based on having validated the computational method by comparing the computational result of an existing case with the corresponding experiment. The results showed that the tumble was formed at the initial stage of the compression stroke. At the end of compression, although a part of residual tumble vortex still existed in the central part of the combustion chamber, the tumble in other parts of the combustion chamber had broken into small vortices and eddies. The stronger tumble could be formed under a smaller intake valve lift in the intake process, and thus the stratified mixture could be more easily formed using with injecting at the intermediate and later stage of intake stroke. Key words: Lean-Burn; CFD; Tumble; Numerical simulation; LPG 1. 前言 近年来，利用进气滚流形