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: A combustion system for direct injection diesel engines, having a fuel injection nozzle provided with upper and lower rows of nozzle holes and disposed so as to be opposed to a deep dish combustion chamber of a small opening ratio. The directions of the upper nozzle holes (1) in the upper row and those of the lower nozzle holes (2) in the lower row are set so that fuel injected from the upper nozzle holes (1) reaches a side wall of the combustion chamber and fuel injected from the lower nozzle holes (2) impinges upon a bottom surface (4) of the combustion chamber. A ratio of a fuel spray travel from the upper nozzle holes (1) to a diameter of each of the upper nozzle holes is set to 150-250. The number of said upper nozzle holes (1) is set twice as large as that of said lower nozzle holes (2).