【摘要】 在直喷式柴油机气道稳流试验中,采用变压差试验方法代替传统的定压差方法。在气门升程最大时,将气道压差定到足以使流经气道内的空气为充分发展的湍流,采用涡流动量计,进行了直喷柴油机6108缸盖的气道稳流变压差试验。结果表明:变压差气道稳流试验中的Ricardo和FEV方法的流量系数、涡流强度、平均流量系数及涡流比等参数与定压差稳流试验的结果基本相同,最大差别不到1.5%,变压差方法可以替代定压差的气道稳流试验方法。试验结果还表明变压差试验所获得的数据具有良好的重复性和精度。采用变压差试验的方法可以减少气道稳流试验中的调整气道压差为恒值的操作程序,大幅度提高工作效率,利于实现气道试验台的自动化,从而适用于缸盖的在线检测。更多还原

【Abstract】 A method for steady flow test of inlet port with variable pressure drop instead of constant pressure drop was used in the study.With this method,the pressure drop across the port was set large enough at the maximum valve lift,which could make air to be fully developed into the turbulent flow.With lowering of valve lift,the in-cylinder pressure drop will rise and the parameters like flow rate and swirl intensity are measured automatically without any manual adjustment.An impulse swirl meter was used to measure the flow characteristics of the inlet port in a steady flow rig.The results showed that the non-dimensional parameters such as flow coefficient,non-dimensional rig swirl,mean flow coefficient and swirl ratio with variable pressure drop were approximately the same as those with constant in-cylinder pressure drop,and the maximum deviation was less than 1.5%.It was concluded that the method of variable pressure drop could be used to replace the constant pressure drop method.Meanwhile,the new method can meet the requirements of measuring accuracy with easy operation and short measuring period,making it easily to realize full automation for steady flow test and suitable for on-line cylinder head production inspection.更多还原