| 摘要 |
PROBLEM TO BE SOLVED: To provide a negative pressure control device for an on-vehicle internal combustion engine capable of ensuring brake performance and suppressing a deterioration of fuel consumption. SOLUTION: Negative pressure generated in an intake air system of an engine 11 is accumulated in a brake booster 50 as booster internal pressure, and the booster 50 is actuated on the basis of brake negative pressure which is differential pressure between atmospheric pressure and the booster internal pressure. When the brake negative pressure does not achieve a necessary value for actuating the brake booster 50, a throttle valve 23 is controlled to a closing side to ensure necessary negative pressure. The throttle valve 23 is opening- controlled according to a margin of the brake negative pressure PBK with reference to the necessary value for actuating the brake booster 50. Namely, if the margin is small, the throttle opening is made to take a closing side value, thereby promptly ensuring the brake negative pressure when an shortage of the brake negative pressure occurs. If the margin is large, the throttle opening is made to take an opening side value, thereby reducing a pumping loss. |
