Abstract: An exhaust gas purifier including a casing, SCR catalysts (comprising a first SCR catalyst and a second SCR catalyst), a first backflow prevention plate, and a second backflow prevention plate. In the casing, at least a part of the catalyst passage and at least a part of the bypass passage are formed. The SCR catalysts are disposed in the catalyst passage and selectively reduce NOx included in an exhaust gas flowing in the catalyst passage. The first backflow prevention plate prevents or reduces a backflow of an exhaust gas from a second exhaust passage to the catalyst passage.

Abstract: An exhaust gas purifier including a casing, SCR catalysts (comprising a first SCR catalyst and a second SCR catalyst), a first backflow prevention plate, and a second backflow prevention plate. In the casing, at least a part of the catalyst passage and at least a part of the bypass passage are formed. The SCR catalysts are disposed in the catalyst passage and selectively reduce NOx included in an exhaust gas flowing in the catalyst passage. The first backflow prevention plate prevents or reduces a backflow of an exhaust gas from a second exhaust passage to the catalyst passage.

Abstract: An exhaust gas purification device including: a spray nozzle provided in an exhaust pipe of an engine; a mixer provided downstream of the spray nozzle in a flow direction of exhaust gas; and a catalyst reactor provided downstream of the mixer. The exhaust gas purification device is configured to spray a reducing agent from the urea water spray nozzle to the exhaust gas from the engine, to mix the reducing agent with the exhaust gas in the mixer, and to reduce nitrogen oxides in the exhaust gas using the catalyst reactor. The mixer includes a cylindrical body and a plurality of fins arranged in the cylindrical body radially outward with respect to the axis of the cylindrical body. The upstream portion of each fin is shaped to provide a cutoff portion.

Abstract: An exhaust gas purification device (1) including: a spray nozzle (2) provided in an exhaust pipe of an engine (18); a mixer (11) provided downstream of the spray nozzle in a flow direction of exhaust gas; and a catalyst reactor (12) provided downstream of the mixer. The exhaust gas purification device is configured to spray a reducing agent from the urea water spray nozzle to the exhaust gas from the engine, to mix the reducing agent with the exhaust gas in the mixer, and to reduce nitrogen oxides in the exhaust gas using the catalyst reactor. The mixer includes a cylindrical body (21) and a plurality of fins (22) arranged in the cylindrical body radially outward with respect to the axis of the cylindrical body. The upstream portion of each fin is shaped to provide a cutoff portion (221).

Abstract: An object is to provide an engine in which the exhaust manifolds capable of switching a dynamic pressure supercharging method and a static pressure supercharging method can be easily changed to the exhaust manifolds only of the dynamic pressure supercharging method or only of the static pressure supercharging method without replacing exhaust manifolds themselves. In an engine in which a plurality of independent exhaust manifolds is respectively connected to a supercharger, end parts of the exhaust manifolds are coupled to each other by one or more coupling pipes, an on/off valve that brings the exhaust manifolds into an independent state is provided each of in the coupling pipes, and the coupling pipe is configured such that a part including the on/off valve or the on/off valve is detachable from the exhaust manifolds.

Abstract: An object is to provide an engine in which the exhaust manifolds capable of switching a dynamic pressure supercharging method and a static pressure supercharging method can be easily changed to the exhaust manifolds only of the dynamic pressure supercharging method or only of the static pressure supercharging method without replacing exhaust manifolds themselves. In an engine in which a plurality of independent exhaust manifolds is respectively connected to a supercharger, end parts of the exhaust manifolds are coupled to each other by one or more coupling pipes, an on/off valve that brings the exhaust manifolds into an independent state is provided each of in the coupling pipes, and the coupling pipe is configured such that a part including the on/off valve or the on/off valve is detachable from the exhaust manifolds.