Patent ID: 7331170

Claim:
An exhaust emission control device with a post-processing device for allowing exhaust gas to pass therethrough for gas purification incorporated in an exhaust pipe of an internal combustion engine, comprising a plasma generator arranged upstream of the post-processing device for discharging electricity into the exhaust gas to generate plasma, flow-through type oxidation catalyst arranged upstream of the plasma generator, fuel adding means arranged upstream of the oxidation catalyst configured for adding fuel in the exhaust gas and temperature increasing means configured for increasing exhaust temperature to a level enough for oxidation reaction on the oxidation catalyst of the fuel added by the fuel adding means; and a temperature sensor arranged between the oxidation catalyst and the plasma generator for detecting exhaust temperature, fuel being added properly by the fuel adding means only on a condition that a detected value of the temperature sensor exceeds a predetermined threshold, the temperature of the exhaust gas being increased by the temperature increasing means before the fuel addition by the fuel adding means on a condition that the detected vale of the temperature sensor is below the predetermined threshold.