Automobile engine management method, useful in lean burn operation, uses catalyst storage capacity value determined from point of inflection in NOx flow rate curve

摘要

A predefined NOx storage capacity is determined by the point of inflection (W) in the NOx vs. time graph, from a signal representing the mass flow rate of NOx downstream of the storage catalyst (21). The mass flow rate of NOx is determined as a function of this storage capacity. The storage catalyst is regenerated as a function of the NOx mass flow rate. The relative rate of increase at the point of inflection (W) is predefined, and the mass flow rate is determined as a function of it. In a variant method, the storage capacity and/or the relative rate of growth is measured previously for a reference storage catalyst, and this information is recorded. The capacity or relative rate of growth is measured as a function of the temperature and/or mass flow rate of exhaust gas and/or NOx mass flow rate. The mass flow rate of NOx downstream of the catalyst, may be determined in accordance with equations provided. Independent claims are included for; (1) A computer program product; (2) A corresponding control equipment; and (3) An engine including the above components.