在一台1.8 L汽油机上,研究了部分负荷工况下引入均质废气稀释与提高滚流比对发动机燃油经济性及燃烧特性的影响.其中高滚流比通过进气歧管上的可控翻板实现,并在气道稳流试验台上进行了流动特性试验.结果表明,通过引入废气稀释可以有效改善燃油经济性,燃油消耗率最高可降低18.2％.但过多的废气会使燃烧恶化,带来循环变动升高、总燃烧期延长和燃烧效率下降等问题.将高滚流比与废气稀释相结合,有效弥补废气对燃烧造成的不良影响.滚流比提高后,最大爆发压力与压升率均有明显提升,最高提升幅度分别为24.5％和116.7％,同时循环变动降低.%Investigation on the effect of exhaust gas dilution and tumble ratio on combustion characteristics of a 1.8 L gasoline engine at partial load was made. High tumble ratio was achieved through controlling the plate in the intake manifold. Experiment on flow characteristics were made on a steady flow test rig. Results show that exhaust gas dilution can improve the fuel economy. Fuel consumption is reduced up to 18.2%. However, too much exhaust gas will deteriorate the combustion, increasing cycle-by-cycle variations and combustion duration, and decreasing combustion efficiency. High tumble ratio combined with exhaust gas dilution will compensate the adverse impact from exhaust gas dilution. Maximum cylinder pressure and maximum rate of pressure rise increase while cycle-by-cycle variations decrease with the increase of tumble ratio.
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