Patent ID: 8434297

Claim:
An exhaust purification system of an internal combustion engine comprising: a NOx catalyst device for storing NOx; an exhaust passage located upstream of the NOx catalyst device; an electronic control unit including instructions for causing the electronic control unit, when an amount of NOx held by the NOx catalyst device of the exhaust purification system reaches a predetermined threshold, to perform the steps of: commencing a regeneration treatment by causing an amount of fuel supplied to a combustion process of the internal combustion engine to increase so as to change an air-fuel ratio of exhaust gas of the internal combustion engine from a first lean air-fuel ratio to a set rich air-fuel ratio; and supplying uncombusted fuel with a higher boiling point than that of combusted fuel to the exhaust gas in the exhaust passage, so that the uncombusted fuel is combined with the combusted fuel present in the exhaust gas and the combination is supplied to the NOx catalyst device, during at least one of: a first period in which an air-fuel ratio of the exhaust gas within the NOx catalyst device gradually changes from the first lean air-fuel ratio to the set rich air-fuel ratio when the regeneration treatment is started, and a second period set after an air-fuel ratio of the exhaust gas within the NOx catalyst device becomes a stoichiometric air-fuel ratio indicative of the regeneration treatment being completed.