Compensation of the exhaust gas transport dynamics for accurate instantaneous emission measurements
Compensation of the exhaust gas transport dynamics for accurate instantaneous emission measurements
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DOI：
10.1021/es0353513
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发表时间：
2004-10-01
影响因子：
11.4
通讯作者：
Weilenmann, M
中科院分区：
文献类型：
--
作者：
Ajtay, D;Weilenmann, M
车辆瞬时排放模型将污染物排放量描述为汽车行驶状态的函数。具有高时间分辨率的底盘测功机测试的排放测量对于开发此类模型是必要的。然而，汽车排气系统和测量线中气体传输的动态持续时间明显长于 1 秒。在简化的方法中，传输动力学可以分为两个部分：完美的时间延迟，对应于废气的活塞式传输，以及动态部分，对应于沿途湍流的气体混合。这决定了分析仪上出现的发射峰的时间比车辆中实际形成位置的发射峰的时间更长且高度更低。这里显示了如何使用信号理论方法从分析仪记录的平坦发射信号中重建其形成位置处的尖锐发射信号。还给出了使用原始或稀释分析系统时重建质量之间的比较。
Instantaneous emission models of vehicles describe the amount of emitted pollutants as a function of the driving state of the car. Emission measurements of chassis dynamometer tests with high time resolution are necessary for the development of such models. However, the dynamics of gas transport in both the exhaust system of the car and the measurement line last significantly longer than 1 s. In a simplified approach, the transport dynamics can be divided into two parts: a perfect time delay, corresponding to a piston-like transport of the exhaust gas, and a dynamic part, corresponding to the mixing of gases by turbulence along the way. This determines the occurrence of emission peaks that are longer in time and lower in height at the analyzer than they actually are in the vehicle at their location of formation. It is shown here how the sharp emission signals at their location of formation can be reconstructed from the flattened emission signals recorded at the analyzer by using signal theory approaches. A comparison between the reconstructions quality when using the raw or the dilution analyzer system is also given.