| 摘要 |
PURPOSE:To improve an air-fuel ratio and characteristics of an exhaust gas, by arranging such that a correction factor of an air-fuel ratio is maintained at a value as applied immediately before shifting into a speed changing zone at the time of speed changing, and at its mean value while an air-fuel mixture being in a zone tending to lean. CONSTITUTION:The feedback control of air-fuel mixture is carried out in response to a signal emitted by an exhaust gas sensor. At the time of speed change, an air-fuel ratio correction factor K02 for use in the feedback control is calculated (step 4) with an air intake tube having the changing time tD of its internal pressure set as zero (step 3). The factor K02 is set as its mean value KREF in the zone of air-fuel mixture tending to lean (step 8). In this manner, it is possible to most suitably correct the air-fuel ratio, and thereby preventing the deterioration of exhaust gas characteristics under any operation condition. |
