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Determining distribution of nitrate and sulfate in nitrogen oxide storage catalyst involves employing finite element model describing local nitrogen oxide and sulfur oxide exchange in terms of storage efficiency factors
Determining distribution of nitrate and sulfate in nitrogen oxide storage catalyst involves employing finite element model describing local nitrogen oxide and sulfur oxide exchange in terms of storage efficiency factors
For each cell x, y of an X . Y matrix in the NOx storage catalyst, loading and unloading with NOx and SOx is calculated iteratively as function of the following: NOx and SOx emissions ahead of the catalyst, temperature of the catalyst discs x or the exhaust gas temperature ahead of the catalyst, exhaust gas mass flowrate and the lambda value ahead of the catalyst. X is the number of catalyst discs in the direction of flow; x and y are the numbers of successive wash coats in their thickness direction y. Calculation of loading and unloading is effected successively for each catalyst disc x, where x lies between unity and a maximum value X in the flow direction x. It is effected inside each catalyst disc successively from the outermost (x, 1) to the innermost wash coat cell (x, Y). Preferred Features: Calculated NOx and SOx emission from the xth catalyst disc is used as an input magnitude for the (x + 1)th catalyst disc. Starting from an NOx storage of 100%, for each cell, the storage is corrected by four factors (N1-N4), each of which can represent a group of effects. N1 represents the reaction dynamics of the NOx storage catalyst in the X direction, as a function of temperature and spatial velocity. N2 represents decrease in NOx storage capability as a result of thermal aging. N3 represents decrease of NOx storage capability as a result of sulfur storage, N4 represents reduction of NOx storage capability by saturation of the storage cells with nitrates. The factors are further analyzed, for example, N2 is a collective function of N2.1, N2.2 and N2.3, representative of damage to the storage components, damage to the noble metal components and separation of the storage and the noble metal components. The method is further detailed and developed, applying a closely-similar treatment, to represent the storage capability for SOx.
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机译：对于每个像元，X的y。 NOx存储催化剂中的Y矩阵，NOx和SOx的装载和卸载根据以下函数进行迭代计算：催化剂之前的NOx和SOx排放，催化剂盘x的温度或催化剂之前的排气温度，排气气体质量流量和催化剂之前的λ值。 X是在流动方向上的催化剂盘的数量; x和y是在其厚度方向y上连续的涂层的数量。对于每个催化剂盘x，相继进行装载和卸载的计算，其中，x在流动方向x上位于1和最大值X之间。从最外侧（x，1）到最内侧洗涂室（x，Y）依次在每个催化剂盘内部进行。优选特征：从第x个催化剂盘算出的NOx和SOx排放用作第（x + 1）个催化剂盘的输入量。对于每个单元，从100％的NOx存储开始，通过四个因子（N1-N4）校正存储，每个因子可以代表一组效应。 N1代表NOx存储催化剂在X方向上的反应动力学，其是温度和空间速度的函数。 N 2表示由于热老化而导致的NO x储存能力的降低。 N 3表示由于硫的储存而导致NO x储存能力的降低，N 4表示通过使储存单元充满硝酸盐而导致NO x储存能力的降低。进一步分析这些因素，例如，N2是N2.1，N2.2和N2.3的集合函数，代表对存储组件的损坏，对贵金属组件的损坏以及存储和贵金属的分离组件。对该方法进行了进一步的详细说明和开发，并应用了相似的处理方法来表示SOx的存储能力。
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