Patent ID: 7337608

Claim:
An exhaust gas purifying system comprising a filter provided in an exhaust passage of an internal combustion engine for accumulating particulate matters, an oxidation catalyst provided on the upstream side of said filter, an exhaust throttle valve provided on the upstream side of said oxidation catalyst or on the downstream side of said filter, a first exhaust temperature sensor provided at the inlet of said oxidation catalyst, a second exhaust temperature sensor provided between said oxidation catalyst and said filter, and a control device for regeneration of said filter, characterized in that said control device, upon the execution of control for regeneration of said filter, raises the temperature of the exhaust gas, by performing delay multi-step injection control in a state of closing said exhaust throttle valve, when the exhaust temperature detected by said first exhaust temperature sensor is a given first determining temperature or less; and controls to open said exhaust throttle valve in a stepwise or continuous manner after the exhaust temperature detected by said first exhaust temperature sensor has risen to a given second determining temperature or higher, in such a way that the exhaust temperature detected by said second exhaust temperature sensor rises to a given third determining temperature or higher.