| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an internal combustion engine reducer adding valve diagnostic device preventing a situation that open fixed condition of an adding valve is determined as normal by executing accurate normal determination of the adding valve irrespective of existence of fuel adding process. <P>SOLUTION: If it is determined that possibility of adhesion of reducer on an exhaust system is high, a normal determination requirement A is not satisfied (no in S102) and normal determination (S110) is not given. Normal determination (S110) of the adding valve based on actual measured air fuel ratio A/F is prohibited under such a condition where possibility of adhesion of reducer on the exhaust system is high. Consequently, normal determination is not given although the adding valve is under the open fixed condition. A condition where it is determined that possibility of adhesion of reducer is low is set as an essential requirement for normal determination of the adding valve determined based on the actual measured air fuel ratio A/F. Consequently, reliability of normal determination becomes very high and normal determination of the adding valve is accurately executed. <P>COPYRIGHT: (C)2008,JPO&INPIT |
