Patent ID: 7051521

Claim:
An exhaust aftertreatment system, comprising a particulate filter arranged in an exhaust pipe through which flows exhaust gas from a diesel engine; a NO x -absorption reduction catalyst arranged in the exhaust pipe and downstream of said particulate filter; a bypass line for diverting the exhaust gas having passed through said particulate filter from the reduction catalyst to downstream; a selector valve adapted to be switched over to guide the exhaust gas having passed through said particulate filter either to the reduction catalyst or to the bypass line; an outer cylinder into which the exhaust gas having passed through the particulate filter is guided; an inner cylinder coaxially arranged in said outer cylinder and to which the NO x -absorption reduction catalyst is charged; a space between said inner and outer cylinders utilized as the bypass line, said selector valve arranged at an inlet in said outer cylinder; and a valvate cylinder is arranged in the inlet in said outer cylinder such that an axis of said valvate cylinder extends perpendicular to an axis of the outer cylinder, said valvate cylinder being formed with an exhaust gas guide port through which the exhaust gas having passed through the particulate filter is guided, a first port in communication with an inside of the inner cylinder and a second port in communication with the bypass line, a valve body being arranged in the valvate cylinder such that the valve body may be switched over between a position where the exhaust gas guide port is communicated with the first port and the second port is blocked off and a position where the exhaust gas guide port is communicated with the second port and the first port is blocked off, thereby providing the selector valve.