| 摘要 |
<P>PROBLEM TO BE SOLVED: To restrain brake feeling of a driver from getting worse in booster efficacy characteristic control. <P>SOLUTION: A booster is determined to reach an assisting limit, when a decrease amount of booster negative pressure from that in a stationary state comes to a set decrease value or more, when a decrease gradient of master cylinder hydraulic pressure gets to the first set value or less, and when an increase gradient of the master cylinder hydraulic pressure gets to the second set value or less. An actual relation between the booster negative pressure before a brake operation and the hydraulic pressure in the assisting limit is obtained based on a plurality of sets of the master cylinder hydraulic pressure when the booster reaches the assisting limit and the booster negative pressure in the stationary state. The booster is detected to have reached the assisting limit, using the actually acquired relation, to execute the booster efficacy characteristic control. The booster efficacy characteristic control is started from proper timing, as a result thereof, and the brake feeling of the driver is restrained from getting worse. <P>COPYRIGHT: (C)2010,JPO&INPIT |
