Method for treating particle filter used to purify exhaust gases from internal combustion engine involves injecting ozone into exhaust gases

The ozone is injected into the exhaust gases when their temperature is less than or equal to 250[deg]C. The amount of ozone injected is greater than the amount of NOx present in the exhaust gases. The ozone is injected when the amount of NOx present in the exhaust gases is less than or equal to 100ppm. The ozone is injected in the opposite direction of flow to that of the exhaust gases, upstream of the particle filter (3) or in it. The ozone is injected when two conditions are met: the temperature of the exhaust gases is less than or equal to 250[deg]C and the mass of soot present in the particle filter is greater than a preset value, preferably between 0 and 5g. In addition there is a stage of treating the residual ozone and/or the oxidation products from the soot particles, using an oxidation catalyst placed downstream of the particle filter. An independent claim is made for a device for treating a particle filter comprising an exhaust pipe (2) from an internal combustion engine (1), in which a particle filter (3) is placed. An ozone injection device (4) is connected to the exhaust pipe by a pipe (7) and fed with oxygen by an air pump (5) and an air trap (6) catching air outside the vehicle. The air pump and the air trap are each supplied with a valve (8, 9) and a control device (10) connected to the engine, the ozone injection device, the air pump and the valves. The ozone injection pipe is curved and points upstream into the exhaust gases. The ozone is injected into the particle filter and a platinum- based or copper and/or manganese-based oxidation catalyst is placed downstream of the particle filter. L'invention concerne un procédé de traitement d'un filtre à particule 3 pour l'épuration de gaz d'échappement d'un moteur à combustion 1, par injection d'ozone dans les gaz d'échappement, caractérisé en ce que l'ozone est injecté lorsque la température des gaz d'échappement est inférieure ou égale à 250°C, la quantité d'ozone injectée étant supérieure à la quantité de NOx présente dans les gaz d'échappement.