| abstract |
An inlet chamber 40 and outlet chamber 50 for exhaust gas are integrated as an inflow/outflow section 80 , and a first post treatment device 10 equipped with a DPF 13 at its central portion and second post-treatment device 20 equipped with a urea DeNOx catalyst 23 on its outer periphery side are integrated as a catalyst installation section 70 . The catalyst installation section 70 , the inflow/outflow section 80 , and a communication chamber forming section 30 are provided separately and detachably from one another, and the catalyst installation section 70 is made installable in a reversible manner. As a result, by reversing the catalyst installation section 70 , it is possible to easily reverse the DPF 13 without having to extract it from the central part. Further, since the urea DeNOx catalyst 23 is reversed simultaneously, it is possible to change the direction in which the exhaust gas flows therein, thereby enabling to prevent unbalanced deterioration of the urea DeNOx catalyst 23. |