Patent ID: 8168125

Claim:
A diesel oxidation catalyst mounted on an exhaust pipe that exhausts an exhaust gas generated in an engine to the exterior, comprising: a first portion having a hydrocarbon trap (HC trap) coated thereon, the HC trap absorbing or releasing a hydrocarbon (HC); and a second portion having an oxidation catalyst coated thereon, the oxidation catalyst oxidizing the hydrocarbon (HC) and a carbon monoxide (CO) in the exhaust gas; wherein the second portion performs oxidation reaction with the HC released from the first portion and releases sulphur absorbed at the oxidation catalyst by using oxidation heat generated in the oxidation reaction thereof; wherein the HC trap is a beta zeolite; wherein the HC trap absorbs the HC when the temperature of the exhaust gas is lower than a predetermined temperature and releases the HC when the temperature of the exhaust gas is higher than a predetermined temperature; wherein the beta zeolite has a structure of twelve rings and ratio of silica SiO 2 to aluminum oxide Al 7 O 3 is 24-38; and wherein the HC trap is between approximately 30% and approximately 50% of entire washcoat in the first portion.