| 摘要 |
PURPOSE:To obtain a stable idling regardless of change in ambient pressure and the fit condition of engine, by interrupting control by an oxygen concentration sensor and blocking the conduit when the engine speed is below the preset value. CONSTITUTION:When a number-of-revolutions sensor 13 senses a number of revolutions below a certain specified value, the feedback control on the basis of oxygen concentration sensor 8 is interrupted through the action of a logical circuit 14. At this time, a proportional control valve 6 shuts the flow of air passing through a by-pass 5. Therefore a mixture gas is supplied during idling at a richer air-fuel ratio necessary to stabilize revolutions. Accordingly the engine is free from influence of the pressure change or a change on standing to give a stable idling. Even when a neg. pressure switch 7 generates a signal to indicate high load, a high output is obtained at the time of high load owing to a logical circuit 14. |
