| 摘要 |
PROBLEM TO BE SOLVED: To assist brake fluid pressure even when a series of failure occur by supplying/assisting the brake fluid pressure higher than brake fluid pressure of a master cylinder to a wheel cylinder in the failure of a booster, and setting a prescribed value to target deceleration in the failure of a fluid pressure sensor. SOLUTION: Negative pressure of a booster 12 detected by a negative pressure sensor 32 is read to discriminate a failure of a vacuum type booster. Brake fluid pressure of a master cylinder 10 detected by a fluid pressure sensor 34 is read to arithmetically operate target deceleration in the failure of the booster. When the fluid pressure sensor 34 fails, the booster failure time target deceleration of a specific value is set. An ECU 30 drives a pump by actuating a pump driving motor. When deceleration determined from detecting signals of wheel speed sensors 24 to 27 reaches the target deceleration, processing is finished. Thus, even when a failure of the booster and a failure of a master cylinder fluid pressure sensor occur in a series, brake fluid pressure of a wheel cylinder can be assisted.
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