Abstract: In a process for adapting an amount of reducing agent for a removal of nitrogen oxides from the gases in an exhaust line, a first alignment of the amounts of nitrogen oxides measured by upstream and downstream sensors is performed without injection of agent and with a catalyst of the system emptied of ammonia. A second alignment of the estimated reduction of nitrogen oxides with the measured reduction is performed by a difference between amounts of nitrogen oxides upstream and downstream during a substoichiometric injection of reducing agent without creating a store of ammonia in a catalyst of the system with a first correction of the amount of agent. A third alignment of an estimated efficiency of retaining nitrogen oxides with a efficiency measured by the sensors is performed, this third alignment taking place via a second correction of the amount of reducing agent injected as an adaptive correction.

Abstract: A process for optimizing a depollution of nitrogen oxides from the gases in an engine exhaust line carried out according to a selective catalytic reduction by injection of a quantity of reducing agent into the line makes it possible to monitor a setpoint of the amount of nitrogen oxides per second at the outlet of the line. A readjustment of the setpoint is made at each completion of successive running distance intervals determined by integration of the speed over a time interval that ends as soon as a predetermined target cumulative amount of carbon dioxide released is reached, an amount of nitrogen oxides at the outlet per kilometer traveled being calculated for each interval from a cumulative amount of nitrogen oxides measured at the outlet and compared with a target amount of nitrogen oxides per kilometer for the calculation of a deviation used for the readjustment of the setpoint.

Abstract: A method for monitoring an oxidation catalysis device or DOC arranged in an exhaust line of an internal combustion engine of a vehicle, in a predetermined range of inlet (2) and outlet (3) temperatures of the DOC, includes injecting predetermined successive quantities of fuel in stages (5, 6) into the inlet of the DOC, recording the outlet (3) temperature of the DOC after each injected quantity of fuel, recording the total quantity injected for a given stage, for which the outlet temperature (3) of the DOC begins to decrease, determining a characterization of the DOC monitored, then comparing this characterization with a test characterization of a similar DOC which has been established beforehand in order to determine a threshold degradation of the DOC monitored that is not to be exceeded.

Abstract: A method for controlling an injector (1) placed in a motor vehicle exhaust line (2) for the metered injection of a liquid, such as notably a reducing agent, includes commanding openings of the injector for lengths of time that are suited to ensure that the flow of liquid delivered upon each of the openings consists in a drop of liquid by commanding constant injector-opening times, and adjusting the metered dose of liquid injected by varying the frequency of such openings.

Abstract: Method for determining a true amount of active product entering a catalytic device of a vehicle exhaust line includes: introducing, into the exhaust gas stream upstream of the device, an active flow rate of active product so that the contaminant and active product are absent at the measurement probe at the outlet of the device, increasing the active flow rate until the second probe measures a given escape content of the product, stabilizing the escape of product, via the measurement provided by the probe, at the given escape content, introducing a theoretical additional test flow rate of product into the exhaust gas stream upstream of the device, waiting until the total content of product measured in response at the second probe has stabilized, and measuring this stabilized total content, and determining the stabilized true additional test flow rate of active product entering the device.