| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a catalyst thermal degradation determining device and a catalyst thermal degradation restraining device capable of accurately computing a heat received by a catalytic converter even in a fuel cut-off time and positively restraining thermal degradation. <P>SOLUTION: In normal operation, a heating value index a corresponding to exhaust flow and exhaust temperature is computed (S3). In the fuel cut-off time, a heating value index b corrected according to a fuel cut-off elapsed time Tf is computed (S8). These heating value indexes a, b are integrated to obtain a total heating value index c (S10). Whether the total heating value index c is larger than an upper limit total heating value index cmax set according to a travel distance is discriminated to determine thermal degradation (S13). When thermal degradation is determined, slot opening limit control (S15) and fuel cut-off time reduction control (S16) are performed. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
