Exhaust gas processing device for engine

An exhaust gas processing device for an engine comprising:

• a combustible gas producer, a combustion catalyst, an exhaust processing unit, and a control unit, the exhaust gas processing device being configured such that a combustion catalyst burning gas is produced by the combustible gas producer under the control of the control unit, the resultant combustion catalyst burning gas is mixed with an exhaust gas passing an engine exhaust gas channel and catalytically burned with the combustion catalyst, and then, the exhaust gas whose temperature is increased by catalyst combustion is supplied to the exhaust processing unit,
• wherein the control unit allows the combustible gas producer to produce a combustion catalyst warming gas before the combustion catalyst burning gas is produced, the resultant combustion catalyst warming gas is mixed with the exhaust gas passing the engine exhaust gas channel and ignited by an igniter disposed upstream of the combustion catalyst that is thus warmed with the exhaust gas whose temperature is increased by flame combustion;
• the combustion catalyst burning gas is produced in the case where a warming end condition for the combustion catalyst is established;
• and
• the establishment of the warming end condition for the combustion catalyst signifies the establishment of either one of a first condition or a second condition:
• the first condition in which an inlet temperature of the combustion catalyst is equal to or higher than an activation requirement temperature of the combustion catalyst, and further, an outlet temperature of the combustion catalyst is equal to or higher than an activation confirmation temperature of the combustion catalyst in excess of the inlet temperature of the combustion catalyst;
• and the second condition in which the outlet temperature of the combustion catalyst exceeds a warming confirmation temperature of the combustion catalyst that is set to be higher as an engine speed is lower, for a predetermined period of time.