| 摘要 |
PURPOSE:To allow smooth start-up of engine by making such arrangement in bleed air control of air fuel ratio that an air bleed control valve may be controlled in accordance with judgement on whether coolant temperature at the time of engine start-up is at an extremely high level or not. CONSTITUTION:An air bleed control valve 25 is installed to control bleed air volume that is supplied from an air inlet 30 through air channels 31, 32 to main system- and slow system-fuel passages 33, 34 based on forward and backward motion of a needle valve 29 driven by a stepper motor 26. Air fuel ratio of mixed air is controlled with the valve 25, which is in turn controlled with ECU59. Namely, when coolant temperature is at extremely high levels, for instance, more than 100 deg.C at the time of engine start detection, the control valve 25 is fully opened, and when the engine has completed explosion feedback control of the air fuel ratio fixed by coolant temperature is effected. In the case of start-up at the temperature other than extremely high one, the control valve 25 is completely closed, and after complete explosion of the engine similar feedback control is enforced.
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