Patent ID: 8484959

Claim:
A catalyst apparatus for an internal combustion engine that is provided in an exhaust passage of the internal combustion engine and to which reducing agent is supplied from upstream when the temperature of exhaust gas is to be raised, comprising: a first catalyst having an oxidizing ability that is configured in such a way that the exhaust gas flows through a gap between its outer circumferential surface and an inner circumferential surface of said exhaust passage; and a second catalyst having an oxidizing ability that is disposed downstream of the first catalyst with a space having a specific width between it and the first catalyst and configured in such a way that the exhaust gas flows through a gap between its outer circumferential surface and the inner circumferential surface of said exhaust passage, wherein a cross sectional area of said second catalyst in the direction perpendicular to an axial direction is larger than a cross sectional area of said first catalyst in a direction perpendicular to the axial direction.