Patent ID: 8051646

Claim:
A particulate filter regenerating system comprising: a fuel injection device adapted to inject fuel into a combustion chamber of an engine; and an exhaust gas temperature-adjusting device adapted, when a PM deposit amount which is an amount of particulate matter deposited in a particulate filter having a plurality of cell walls with pores and outer surfaces and provided in an exhaust passage of the engine reaches a predetermined value, to cause the fuel injection device to perform a post-injection for injecting fuel into the combustion chamber during an expansion stroke of the engine, so as to execute a filter regeneration process of raising a temperature of exhaust gas flowing into the particulate filter to burn the deposited PM, and a temperature sensor adapted to detect a temperature of exhaust gas flowing on a downstream side of the particulate filter, wherein the exhaust gas temperature-adjusting device is operable to identify a timing at which the reduction rate of the PM deposit amount becomes less than the predetermined value, based on a temporal change in exhaust gas temperature detected by the temperature sensor, wherein the exhaust gas temperature-adjusting device is operable to perform a normal filter regeneration process which includes: a first stage which causes the fuel injection device to perform the post-injection to primarily burn and remove the PM within the cell-wall pores in the particulate filter until the reduction rate of the PM deposit amount becomes less than the first threshold value; and a second stage which causes the fuel injection device to perform the post-injection to simultaneously burn and remove a remaining PM within the cell-wall pores and a part of the PM deposited on the cell-wall outer surface of the particulate filter until the reduction rate of the PM deposit amount becomes less than the second threshold value, wherein the exhaust gas temperature-adjusting device is operable, after repeating said normal filter regeneration process a predetermined number of times, to perform a complete filter regeneration process which causes the fuel injection device to continuously perform the post-injection until the PM burning amount becomes approximately equal to the initial PM deposit amount.