Patent ID: 7607292

Claim:
A fuel addition apparatus for adding fuel into an exhaust passage of an internal combustion engine, the fuel addition apparatus comprising: a fuel adding valve for adding fuel into the exhaust passage of the internal combustion engine having a nozzle and nozzle hole exposed to the interior of the exhaust passage; a crank position sensor for determining whether the fuel adding valve itself has entered a high temperature region on the basis of number of rotations of the engine and the amount of fuel injected into the engine; an addition amount calculating section which calculates a fuel addition amount on the basis of the elapsed time after the point in time when the temperature of said fuel adding valve itself enters the high temperature region and based on the number of rotations of the engine; and an addition controlling section which controls addition of fuel on the basis of said calculated fuel addition amount and said elapsed time to prevent wasteful fuel addition, wherein clogging of the nozzle hole due to calking of substances such as soot and SOF deposited thereon, or adhered thereto, is limited or prevented.