Importance

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Abstract

Apparatus and method for estimating the temperature of a catalytic converter for automotive engine can be estimated simply and accurately. Specifically, the cooling water temperature Tws at start-up is presumed to correspond to the ambient temperature, and a lost heat amount Tm is estimated based on the cooling water temperature Tws at start-up, and on the vehicle speed VSP. Then, a time integral value STm of the lost heat amount Tm is computed. On the other hand, the engine intake air quantity Q is presumed to correspond to an exhaust quantity, and a received heat amount Tp, which the catalytic converter absorbs from the exhaust, is estimated based on the intake air quantity Q. Then, a time integral value STp of the absorbed heat amount Tp is computed. The time integral value STm is then subtracted from the time integral value STp to obtain a heat amount X retained in the catalytic converter. The heat amount X is then compared with a predetermined value to estimate if the catalytic converter has reached an activation temperature.

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First Claim