| 摘要 |
PURPOSE:To control an air-fuel ratio to a rich side even at the time of a low temp. so that NOX can be decreased by varying a feedback control constant according to the temp. in the sensor part of an oxygen sensor. CONSTITUTION:The oxygen sensor 9 which detects the oxygen concn. in the exhaust gas in an exhaust passage 8 of an engine 1 and a ternary catalyst 10 which executes oxidation of CO and HC and reduction of NOX in the exhaust gas are provided. The oxygen sensor 9 is mounted with a temp. sensing element 12 as a means for detecting the temp. in the sensor part to detect the temp. in the sensor part on the inside of a ceramic pipe 21. The signal of the temp. in the sensor part from the sensor 12 is inputted together with the respective signals from an air flow meter 3, a water temp. sensor 7 and a crank angle sensor 11 to a control unit 6. A fuel injection rate is computed in accordance with the various signals and the fuel injection is controlled by adjusting a fuel injection valve 5, by which the air-fuel ratio is controlled. |
