| 摘要 |
PURPOSE: To keep the target idle speed by eliminating the insufficient auxiliary air volume due to the reduction in the air density when the engine is hot while keeping the function to suppress the engine speed in the idling condition to a prescribed value or below. CONSTITUTION: First and second branched passages 5, 6 which are branched at the downstream position of an auxiliary air volume control valve 4 and then merged are provided on an auxiliary air passage 3, and first and second auxiliary air volume regulating valves 7, 8 of the temperature sensing type to regulate the auxiliary air volume to the prescribed flow rate based on the cooling water temperature are respectively interposed to the branched passages 5, 6. The total air volume fed to the downstream side of a throttle valve 1 is gradually reduced as the cooling water temperature rises by the characteristic of the auxiliary air volume regulating valves 7, 8, and kept at a certain value in the prescribed temperature range after the cooling water temperature rises to the prescribed value, and gradually increased as the cooling water temperature exceeds the prescribed temperature range and further rises. |
