AIR-FUEL RATIO CONTROL APPARATUS AND METHOD FOR MOTOR VEHICLE BY DUAL OXYGEN SENSOR

摘要

The present invention relates to an air-fuel ratio control apparatus and method using dual oxygen sensors. The apparatus includes an exhaust manifold collecting an exhaust gas of a vehicular engine; a turbo charger transmitting the exhaust gas received from the exhaust manifold to the engine and a muffler; a first exhaust pipe connecting the exhaust manifold and the turbo charger; a muffler connected to a rear end portion of the turbo charger and having a catalyst layer; a second exhaust pipe connecting the turbo charger and the muffler; a first oxygen sensor connected to the first exhaust pipe to measure the oxygen quantity in the exhaust gas thereby to control the air-fuel ratio; and a second oxygen gas connected to the second exhaust pipe to measure the oxygen quantity in the exhaust gas thereby to control the air-fuel ratio. Therefore, it is possible to move up the air-fuel ratio control timing, and reduce the exhaust gas generated in large quantities in the initial stage of the start. Also, it is possible to ensure the combustion stability by combusting the fuel in line with the air-fuel ratio.