Injection and mixing device for exhaust line

An injection and mixing device for an exhaust line, the injection and mixing device comprising:

• a casing having an exhaust inlet and an exhaust outlet, the casing internally defining a passage for exhaust gases from the exhaust inlet to the exhaust outlet, the exhaust inlet opening into an inlet region of the passage;
• an injector of a liquid comprising a nitrogen oxide reducing agent or a precursor of the nitrogen oxide reducing agent, the injector being mounted on a wall of the casing directed towards the exhaust outlet, and the injector injecting liquid in a direction of injection towards the exhaust outlet;
• a deflector housed within the casing and defining in the passage a first passage connecting the inlet region to the exhaust outlet, in which the exhaust gases flow at a first average velocity, and a second passage connecting the inlet region to the exhaust outlet, in which the exhaust gases flow at a second average velocity lower than the first average velocity, the injector injecting liquid into the second passage, and wherein the deflector comprises an impactor plate that is interposed between the injector and the exhaust outlet, and wherein the impactor plate is planar and has a less than 25° angle normal to the direction of injection;
• and
• wherein the deflector includes a perforated plate that is upstream from the impactor plate, and including a gap between a downstream edge of the perforated plate and an upstream edge of the impactor plate.