| 摘要 |
An internal combustion engine provided with an exhaust purification catalyst (13) arranged in an exhaust passage, a hydrocarbon feed valve (15) arranged upstream of the exhaust catalyst (13), and a hydrocarbon feed device (60) for feeding hydrocarbons to the hydrocarbon feed valve (15). The hydrocarbon feed device (60) has the function of making an injection pressure PX of the hydrocarbon feed valve (15) increase, but does not have the function of making it decrease. The injection pressure PX of the hydrocarbon feed valve (15) includes a limit injection pressure PZ which causes slip through of hydrocarbons at the exhaust purification catalyst (13). When the injection pressure PX of the hydrocarbon feed valve (15) exceeds an allowable injection pressure PZO which is lower than the limit injection pressure PZ by exactly a predetermined pressure, the hydrocarbon feed valve (15) injects hydrocarbons to thereby make the injection pressure PX of the hydrocarbon feed valve (15) fall. |
