Method and apparatus for monitoring the light-off temperature of a diesel oxidation catalyst

摘要

A method is provided for monitoring the light-off temperature of a diesel oxidation catalyst of a combustion engine. The method includes, but is not limited to measuring the temperature of the exhaust gas upstream and downstream of the diesel oxidation catalyst during a post injection phase or after injection phase of the combustion engine, determining whether a catalyst light-off occurred by using the temperature data of the exhaust gas, calculating the surface temperature of the diesel oxidation catalyst by using the measured temperature data of the exhaust gas, and defining the calculated temperature as light-off temperature of the diesel oxidation catalyst in the case that a catalyst light-off is determined. By means of the method, it is possible to determine the actual light-off temperature of the diesel oxidation catalyst for instance after each engine start by means of calculating the surface temperature of the diesel oxidation catalyst. Since the light-off temperature is not considered as a constant but as a changing variable, the aging of the diesel oxidation catalyst is sufficiently considered. Thus, it is provided a means for monitoring the light-off temperature of a diesel oxidation catalyst considering an aging of the diesel oxidation catalyst.

主权项

1. A method for monitoring a light-off temperature of a diesel oxidation catalyst of a combustion engine, comprising the steps of:
measuring a temperature of an exhaust gas upstream and downstream of the diesel oxidation catalyst during a post injection phase or after injection phase of the combustion engine; determining whether a catalyst light-off occurred by using the temperature of the exhaust gas; calculating a surface temperature of the diesel oxidation catalyst by using the temperature of the exhaust gas; and defining the calculated surface temperature as the light-off temperature of the diesel oxidation catalyst if the catalyst light-off is determined; storing the light-off temperature in an engine control unit such that the engine control unit may utilize the light-off temperature in operating the combustion engine; comparing the surface temperature with the previously stored light-off temperature; replacing the previously stored light-off temperature with the surface temperature if greater than a negligible difference between the surface temperature and the stored light-off temperature is determined; defining the previously stored light-off temperature as the tight-off temperature if at least one of no light-off is determined and only a negligible difference between the calculated surface temperature and the previously stored light-off temperature is determined; and utilizing the light-off temperature to control post-injection of fuel into the cylinders of the combustion engine.