Method for reducing the amount of NOx in the exhaust gases of a motor vehicle

摘要

The invention relates to a method for controlling a system for reducing the amount of NOx in the exhaust gases of a motor vehicle. The system comprises a storage chamber (8) which contains a pollutant-removing agent and which is arranged such that the temperature thereof is controlled by a heating device (9). The system further comprises a supply module (6) arranged so as to inject the pollutant-removing agent into the exhaust gases, the supply module (6) comprising a device for measuring the pressure (6a) or the temperature inside the storage chamber (8), as well as a device (6b) for proportioning the pollutant-removing agent. The control method involves, for example: defining a predetermined moving criterion, in particular on the basis of the engine torque during a first period; filtering the moving criterion with a filtering period (T1) corresponding to the first period; comparing the filtered moving criterion with various thresholds in order to determine a type of moving; determining the elapsed time for each type of moving during a second period (T2) in order to associate a trend representing moving conditions throughout said second period; calculating a set pressure or set temperature according to the type and the trend representing past moving conditions; comparing the set pressure or set temperature with the pressure or temperature measured by the pressure- or temperature-measuring device (6a); and heating the storage chamber (8) if the pressure or temperature inside the latter is lower than the set pressure or set temperature.

主权项

1. A method for controlling a system intended to reduce an amount of NOx in exhaust gases of a motor vehicle, the system comprising on-board the motor vehicle:
a storage chamber (8) containing a pollutant-removing agent; a heating device (9) arranged to control a temperature of the storage chamber (8); a feed module (6) arranged to inject the pollutant-removing agent into the exhaust gases, and comprising:
a device (6a) for measuring pressure or temperature inside the storage chamber (8); anda device (6b) for proportioning the pollutant-removing agent; the method comprising the following steps: a) calculating, when the motor vehicle is in operation and for a predetermined driving period, a set pressure or temperature inside the storage chamber (8) according to one or more parameters of the motor vehicle which are a function of a type of driving of said motor vehicle during said predetermined driving period; b) comparing the set pressure or temperature with the pressure or temperature measured by the pressure or temperature measuring device (6a) during operation of the motor vehicle, after said predetermined driving period; and c) heating the storage chamber (8) if the pressure or temperature therein is lower than the set pressure or temperature.