| 摘要 |
<p>PURPOSE: To estimate a catalyst temperature with high accuracy at the time of hot restart by memorizing the catalyst temperature which is estimated just before engine stop till engine restart, and estimating the catalyst temperature at the time of restart from a memorized catalyst temperature and a temperature fall range which is estimated on the basis of an engine stop time. CONSTITUTION: First and second oxygen sensors 16, 17 are arranged upstream and downstream from a catalytic converter rhodium 10, air-fuel ratio feed back control is carried out on the basis of output of the catalyst 16, and slide of a control point at this time is corrected on the basis of the output of the sensor 17. In such a control method, a catalyst temperature is estimated so as to improve reliability of control since the catalytic converter rhodium 10 influences output of the sensor 17. At this time, the catalyst temperature estimated by an estimating means just before engine stop is memorized at the time of engine stop. The fall era of the catalyst temperature is estimated on the basis of the engine stop time, and the catalyst temperature at the time of engine restart is estimated on the basis of the memorized catalyst temperature and the fall era, at the time of restart.</p> |
