EXHAUST GAS PURIFICATION SYSTEM FOR INTERNAL COMBUSTION ENGINE

The exhaust gas purification system includes a catalyst having an NOx storage and reduction function, an EGR passage, and a controller configured to control combustion of the internal combustion engine. The controller is configured to switch the operation mode from the lean burn operation to the rich burn operation, when a request for execution of the rich burn operation is issued during the lean burn operation. The controller is configured to perform, when the request the execution of the rich burn operation is issued, an NOx-increasing process in which the combustion of the internal combustion engine is controlled so that an in-cylinder NOx amount is equal to or larger than a required in-cylinder NOx amount prior to switching to the rich burn operation.