Patent ID: 8443595

Claim:
An additive-agent diffusion device, comprising: an exhaust passage for an engine; an additive agent injection nozzle disposed in the exhaust passage upstream of an exhaust gas purification device in an exhaust-gas flow direction in which the exhaust gas flow; and an additive-agent diffusion plate disposed in the exhaust passage directly downstream of the injection nozzle, and upstream of the exhaust gas purification device, wherein the diffusion plate includes: a plurality of imperforate collision portions with which an additive agent injected into the exhaust passage collide; and a plurality of apertures between each of the plurality of collision portions that allow exhaust gas flowing in the exhaust passage to flow from an area upstream of the additive-agent diffusion plate in an exhaust-gas flow direction, to an area downstream of the additive-agent diffusion plate in the exhaust-gas flow direction; wherein: each of the imperforate collision portions protrudes toward an upstream side in the exhaust-gas flow direction, and a cross section of each of the collision portions increases from the upstream side toward a downstream side in the exhaust-gas flow direction.