| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a device and a method accurately estimating vacuum of a booster. <P>SOLUTION: An estimating method estimates a current booster vacuum P<SB>B</SB>to be the value of the engine vacuum P<SB>E</SB>at the time when it was most recently supposed that a booster vacuum and an engine vacuum were equal to each other (S7, 16), and keeps estimating the current booster vacuum to be the value of the engine vacuum as long as the brake is not operated (S17). When the booster vacuum estimated by the method above is lower than the engine vacuum, an estimating method estimates an increment β of the booster vacuum based on a speed V<SB>B</SB>, by which the booster vacuum is supposed to keep increasing in accordance with the sucking of air from a vacuum chamber, and a time ΔT<SB>0</SB>elapsed from the start of increasing the booster vacuum (S13), and estimates the current booster vacuum to be the value made by adding the estimated increment to the value of the booster vacuum estimated at the start point of increasing the booster vacuum (S14). Either method is selectively carried out. <P>COPYRIGHT: (C)2011,JPO&INPIT |
