CATALYTIC CONVERTER AND METHOD FOR DESIGNING THE CATALYTIC CONVERTER

摘要

A catalytic converter capable of uniformizing an exhaust gas flow velocity to realize uniform temperature distribution and improved purification performance, and a method for designing the catalytic converter. A catalytic converter includes a catalyst base composed of an inner base material part having inner cell holes and an outer base material part having outer cell holes, and an exhaust pipe composed of an upstream-side pipe, a catalyst housing pipe and a downstream-side pipe. In the catalytic converter, a flow path cross-sectional area of the upstream-side pipe defined as S1, a cross-sectional area of the inner base material part defined as S2, a cross-sectional area of the catalyst base defined as S3, a hydraulic diameter of the inner cell holes defined as d1 and a hydraulic diameter of the outer cell holes defined as d2, satisfy the relationship, S1≦S2≦S3(−0.2242 (d12/d22)2+0.1141 (d12/d22)+0.617).

主权项

1. A method for designing a catalytic converter (1), the catalytic converter (1) comprising:
a catalyst base (2) comprising an inner base material part (21) and an outer base material part (23), the inner base material part (21) comprising inner cell holes (211) that allow an exhaust gas to flow therethrough, and the outer base material part (23) being formed outside the inner base material part (21) and comprising outer cell holes (231) each with a hydraulic diameter larger than that of the inner cell holes (211); and an exhaust pipe (3) comprising an upstream-side pipe (31), a catalyst housing pipe (32) and a downstream-side pipe (33), the upstream-side pipe (31) allowing an exhaust gas generated in an internal combustion engine to flow therethrough, the catalyst housing pipe (32) communicating with the upstream-side pipe (31), having a diameter larger than that of the upstream-side pipe (31) and housing the catalyst base (2), and the downstream-side pipe (33) being disposed downstream of the catalyst housing pipe (32) and allowing the exhaust gas purified by the catalyst base (2) to flow therethrough, the method comprising the step of determining dimensions of a flow path cross-sectional area of the upstream-side pipe (31) defined as S1, a cross-sectional area of the inner base material part (21) defined as S2, a cross-sectional area of the catalyst base (2) defined as S3, a hydraulic diameter of the each inner cell hole (211) defined as d1 and a hydraulic diameter of the each outer cell hole (231) defined as d2 so as to satisfy relationships of S1≦S2≦S3(−0.2242(d12/d22)2+0.1141(d12/d22)+0.617) and 0.24≦(d12/d22)2≦0.82.