Catalyst oxygen purge control apparatus and method

A catalyst oxygen purge control apparatus, comprising:

• an exhaust system which exhausts an exhaust gas generated in an engine;
• a three way catalytic converter (TWC) which supplies a catalyst to the exhaust system;
• an oxygen sensor which detects an oxygen storage capacity (OSC) of the three way catalytic converter;
• and
• an electric control unit which is configured to quantitatively determine a degradation level of the catalyst using the oxygen storage capacity to determine a change control condition which changes an oxygen purge time of the three way catalyst, and controls the catalytic converter according to the change control condition to control the oxygen purge time,
• wherein the oxygen purge time is determined by the oxygen storage capacity of the three way catalyst, and as the oxygen storage capacity is reduced, the oxygen purge time is configured to be increased, and
• wherein the oxygen storage capacity is determined in accordance with a degradation level of the three way catalyst, and as the degradation level of the three way catalyst is increased, the oxygen storage capacity is configured to be reduced.