增压柴油机废气再循环（EGR）系统的优化设计

废气再循环技术（EGR）是解决柴油机NOx排放的有效措施之一．以增压柴油机为研究对象，对比分析了不同废气再循环方式的优劣；解决了部分工况下进排压逆差问题；通过建立带有EGR系统的柴油机模型和实验验证，优化满足要求的EGR系统．研究表明，采用带有合适的进、喉口比例尺寸的文丘里管解决了进排压逆差问题，不同工况下采用合适的EGR率保障了柴油机的工作性能，并有效降低了NOx的排放．

Design and Optimization of Exhaust Gas Recirculation System for Turbo-Charged Diesel Engine

Appling exhaust gas recirculation system（EGR）to diesel is one of the most effective measures to reduce the emission of NOx. Based on a turbo - charged diesel engine, the virtues and defects of different EGR modes are compared and analyzed. The problem of reverse pressure difference between intake air and exhaust gas is solved. The EGR system is designed and optimized through establishing and examining a diesel engine model with EGR. It is shown though the result that the problem of reverse pressure difference is solved by adopting the Venturi tube with appropriate proportion between intake and throat. Adopting appropriate EGR ratio at different conditions can not only guarantee diesel engine＇ s performance but also decrease the amount of NOx.