| 摘要 |
PURPOSE:To prevent the deterioration of operability in the transient operation of an internal-combustion engine by making an air-fuel ratio lean in accordance with the values of operational parameters. CONSTITUTION:Information, such as a vehicle speed, an engine speed, and the like, is supplied to a CPU 29 in a control circuit 20. When the CPU 29 judges that a vehicle speed changing rate is below a given value and therefore an internal-combustion engine 5 is in a normal operational condition, the valve opening duty ratio of an electromagnetically operated valve 9 is calculated. The higher the shift position of a transmission is and the higher the vehicle speed is, the larger the valve opening duty ratio is. When the duty ratio is calculated, a valve opening specifying command is fed to a drive circuit 28 and the electromagnetically operated valve 9 is opened for a time in proportion to the duty ratio, supplying secondary air to the engine 5. Thus, an air-fuel ratio is made lean in a rate in accordance with the values of a plurality of operational parameters and the ratio is not made lean in a transient operational condition, preventing the fall of an engine power.
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