| abstract |
This exhaust gas purification system for an internal combustion engine is provided with an exhaust gas purifying catalyst that purifies NO X , and an aftertreatment device. The exhaust gas purifying catalyst has the property of reducing NO X when the concentration of hydrocarbons is made to oscillate at an amplitude within a predetermined range and a cycle within a predetermined range, and further, has a function for oxidizing hydrocarbons. The exhaust gas purification system supplies hydrocarbons to the exhaust gas purifying catalyst, and performs temperature increase control, whereby the temperature of the aftertreatment device is increased. The exhaust gas purifying catalyst has a high purification rate range that becomes higher than a predetermined NO X purification rate. The temperature increase control involves setting the total supply volume of hydrocarbons, and setting the supply cycle of hydrocarbons within a region at the edge of the high purification rate range, on the side where the supply cycle of hydrocarbons is short. |