| 摘要 |
<p>PROBLEM TO BE SOLVED: To grasp a middle bed temperature of a catalyst converter correctly by deciding a moment temperature of exhaust gas in a first point of an exhaust pipe on the basis of a misfire ratio to be estimated, and also deciding a moment temperature at a middle bed point on the basis of its decided moment temperature. SOLUTION: A mass air flow rate sensor 18 is arranged in an intake manifold 14, and its detected air low rate signal is supplied to an ECU 22 together with information such as angular velocity of a crank shaft a position of a throttle, and a temperature of cooling water. Oxygen sensors 38, 40 are arranged upstream and downstream from a catalyst converter 30 in an exhaust system 16, and an oxygen including rate in exhaust gas in front and rear sides of the catalyst at converter 30 is detected. In the case where a middle bed temperature of the catalyst converter 30 is estimated, a speed single of an internal combustion engine is found out, and also a speed signal of a ratio of misfire caused in the internal combustion engine is found out. A moment temperature of exhaust gas at a prescribed point is decided on the basis of its misfire ratio, and a moment temperature at the middle bed point is decided on the basis of its moment temperature.</p> |
