EXHAUST HEATING METHOD

摘要

This method, in which fuel is added to an exhaust channel (23a) from a fuel addition valve (27a) provided to an exhaust pipe (23) further upstream from an exhaust cleaning device (26), and the fuel added to the exhaust channel (23a) is heated and ignited, whereby the exhaust gas guided from the internal combustion engine to the exhaust cleaning device (26) is heated, is provided with: a step for determining if there is a need for adding fuel to the exhaust channel (23a); a step for setting, when determined in the previous step that there is a need to add fuel to the exhaust channel (23a), the amount of fuel from the fuel addition valve (27a) that should be added to the exhaust channel (23a); a step for establishing the operation state of the internal combustion engine; and a step for controlling the air-fuel ratio of the exhaust discharged from the combustion chamber of the internal combustion engine to the exhaust channel (23a) so that the amounts of generated HC and soot in the exhaust gas flowing through the exhaust channel (23a) are within a low range in the operation state of the internal combustion engine established in the previous step.