车用柴油机进气道优化设计及性能研究

Optimization Design and Performance Study of Diesel Engine Intake Port

针对某高强化2.0 L增压柴油机开发过程中出现的部分工况油耗偏高、烟度较大的问题,采用数值模拟与台架试验相结合的方式,研究了不同涡流比及流量系数进气道方案对整机燃油经济性、排放特性的影响。结果表明,原进气道方案存在气流对冲、涡流比及湍动能不足等问题,是导致燃烧效率偏低的关键原因。基于此提出了进气道优化方案,优化后涡流比提升了14.2%,流量系数提升了26.2%,经台架试验验证,优化方案的平均比油耗降低约5%,同时烟度值明显降低。

For the problems of high strength 2.0 L turbocharged diesel engine,i.e.high fuel consumption and high smoke value in development process,numerical simulation and bench test are performed to study the effects of different swirl ratio and flow coefficient of intake port on the emission and the fuel economy.The results show that the original intake port has the problems of airflow colliding and low swirl ratio and turbulent kinetic energy,which are the key reasons leading to low combustion efficiency.An improved intake port is proposed based on the original scheme,the new swirl ratio is increased by 14.2%and the flow coefficient is increased by 26.2%.Experiment results shows that the fuel consumption of the improved scheme is reduced by about 5%,and the smoke value is reduced obviously.