Patent attributes
An exhaust gas purification device includes a selective catalytic reduction (SCR) device arranged in a downstream exhaust flow path, and a mixer arranged upstream of the selective catalytic reduction device and including a helical flow path that helically guides the flow of exhaust gas from an internal combustion engine. In the exhaust gas purification device, the mixer includes a casing, an injector, and a partition plate. The casing has an upstream opening and a downstream opening and is provided with the helical flow path therein. The injector is arranged in the helical flow path to add a reducing agent to the helical flow path. The partition plate is continuous from the upstream opening to the downstream opening. The partition plate is arranged to divide the inner space of the casing into an upstream side and a downstream side, and defines the helical flow path.