| 摘要 |
PROBLEM TO BE SOLVED: To improve the precision of air-fuel ratio control by correcting and setting a target voltage value according to a target air-fuel ratio to a correction target voltage value according to the rotating speed and load of an speed, and feedback controlling the fuel feed so that the detected voltage value from an oxygen sensor becomes the correction target voltage value. SOLUTION: An oxygen sensor 73 is housed within a sensor case mounted on the outer wall of the 2-cycle engine 2 of an outboard engine 1 to output the detected voltage value according to the oxygen concentration in the burned gas within a cylinder to a control unit 32. The fuel feed to a fuel injection valve 47 is feedback controlled so that the detected voltage value becomes a target voltage value (target air-fuel ratio). At this time, since the detected voltage value to the oxygen concentration in the burned gas in the theoretical air-fuel ratio of the oxygen sensor 73 is differed according to engine operating area, the target voltage value to the theoretical air-fuel ratio is correct and set according to the operating area. The fuel injection quantity is controlled so that the detected voltage value of the oxygen sensor 73 becomes the correction target voltage value. |
