EXHAUST PURIFICATION DEVICE FOR INTERNAL COMBUSTION ENGINE

摘要

In the present invention, an exhaust purification device for an internal combustion engine is provided with a hydrocarbon supply valve disposed in an engine exhaust path, and an exhaust purification catalyst that causes NOx contained in the exhaust gas to react with reformed hydrocarbons. The device is formed so as to carry out a first operational control process during which hydrocarbons are supplied from the hydrocarbon supply valve at an amplitude within a predetermined range and over a cycle within a predetermined range, and a second operational control process, during which the amount of hydrocarbons supplied from the hydrocarbon supply valve during a predetermined period of time is greater than during the first operational control process. During the second operational control process, hydrocarbons are supplied from the hydrocarbon supply valve at an injection pressure less than the hydrocarbon injection pressure during the first operational control process.